CN1717857A - Switching power supply circuit - Google Patents

Switching power supply circuit Download PDF

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Publication number
CN1717857A
CN1717857A CN 200380104394 CN200380104394A CN1717857A CN 1717857 A CN1717857 A CN 1717857A CN 200380104394 CN200380104394 CN 200380104394 CN 200380104394 A CN200380104394 A CN 200380104394A CN 1717857 A CN1717857 A CN 1717857A
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China
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circuit
voltage
rectification
power factor
power
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Chinese (zh)
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安村昌之
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Sony Corp
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Sony Corp
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Publication of CN1717857A publication Critical patent/CN1717857A/en
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Abstract

The invention provides a light switching power supply circuit which has power factor improvement function, can improve the power conversion efficiency of a circuit and miniaturize the circuit. A resonance voltage circuit is at least partially combined with a current resonance converter to manufacture a complex resonance convertor by using semibridge coupling on a primary side. The switched output voltage of the complex resonance convertor is fed back to a rectified current channel by using a power factor improvement transformer (loose coupling transformer VFT) so that a commutation diode generates rectified current intermittently, thus increasing the conduction angle of AC input current and improving power factors. In this way, for instance, the power supply circuit with the power factor improvement circuit does not need to insert a choke into an AC commercial power circuit.

Description

Switching power circuit
Technical field
The present invention relates to have the switching power circuit of the circuit that is used to improve power factor.
Background technology
Recently, can stand the high current of high frequency and the switching device of voltage, so be used for civil power is carried out rectification and most of power circuits of the direct voltage that to require become switch mode power supply circuit because developed.
Switching power circuit has by improving switching frequency realizes transformer and other device of miniaturization, and Switching Power Supply is used as the power supply such as the various electronic devices of high power DC-DC converter.
Usually, when civil power was carried out rectification, the electric current that flows into smoothing circuit formed distorted waveform, had therefore produced the problem that power factor reduces, and power factor is represented the utilization ratio of power supply.
In addition, also need to be used to suppress the measure of the harmonic wave that distorted current waveform produces.
Therefore, the various switching power circuits that append on it, are used to improve the configuration of power factor that have have been advised.As one of this switching power circuit, the switching power circuit of the so-called chokes input system of known employing, in this switching power circuit, the power choke is connected with the electric main circuit, thereby improve the angle of flow that exchanges input current, and therefore improve power factor (please refer to Hei7-263262 number Japanese pending application application (Figure 19)).
Figure 27 illustrates and is configured to the example that utilizes above-mentioned choke input system to improve the switching power circuit of power factor.In this power circuit shown in this figure, the configuration secondary power factor of the former complex resonance converter of advising of the applicant is improved the choke input system of configuration.
Carry one in passing, the power circuit shown in this figure satisfy condition [bearing power Po=150w or higher, and AC-input voltage VAC=100V standard].
Power circuit shown in this figure has common-mode noise filter, and this common-mode noise filter is by being connected to electric main AC formation with common mode choke CMC and two cross capacitors (across capacitor) CL.For example, common-mode noise filter suppresses to be sent to from the switch converters side noise of electric main AC.
Setting comprises rectification and the smoothing circuit of bridge rectifier Di and smmothing capacitor Ci to electric main AC circuit, and is as shown in the drawing.Electric main AC is to the power supply of this rectification and smoothing circuit, and then, this rectification carries out level and smooth with smoothing circuit and rectification is operated, and is equivalent to AC-input voltage VAC and takes advantage of 1 rectification and smooth voltage Ei thereby obtain its level at smmothing capacitor Ci two ends.The switch converters that is positioned at following stages is delivered in this rectification and smooth voltage Ei as DC input voitage.
As the configuration that is used to improve power factor, insertion power choke PCH connects with the circuit of electric main AC.In this case, power choke PCH is inserted on the negative pole circuit of electric main AC.
Therefore, as everyone knows, in the time of on the circuit that power choke PCH is inserted in electric main AC, the inductance L pch of power choke PCH plays the interchange input current harmonics of inhibition from electric main AC inflow rectifier diode, and this rectifier diode constitutes bridge rectifier Di.That is, improve the angle of flow that exchanges input current IAC, thereby improve power factor.
Power circuit shown in this figure has multiple (complex) controlled resonant converter as switch converters, above-mentioned rectification and smooth voltage Ei is delivered to this complex resonance converter operate.In this case, the complex resonance converter refers to switch converters, except being the resonant circuit of resonant mode operation setting for operational transformation with switch converters, this switch converters has the resonant circuit that appends to its primary side or primary side, therefore, in a switch converters, a plurality of resonant circuits are worked with the compound formula.
Controlled resonant converter as the setting of complex resonance converter in power circuit shown in Figure 27 is a current-resonance type.In this case, the current resonance converter has two switching device Q1 and Q2, and this switching device Q1 and Q2 are made of MOS-FET, is connected to each other together by the coupling of the semibridge system shown in this figure.Between the drain electrode and source electrode of switching device Q1 and Q2, damper diode DD1 and DD2 are in parallel with switching device Q1 and Q2 respectively with the direction shown in this figure.
Between the drain electrode and source electrode of switching device Q2, partial resonance capacitor Cp is in parallel with switching device Q2.The electric capacity of partial resonance capacitor Cp and the leakage inductance L1 of elementary winding N1 form antiresonant circuit (part voltage resonant circuit).Therefore, obtained part voltage resonance operation, in service at the part voltage resonance, only when switching device Q1 and Q2 are disconnected, produce voltage resonance.
This power circuit is provided with control IC 2, with switch drive (switching drive) switching device Q1 and Q2.Control IC 2 comprises the oscillating circuit that utilizes external drive system drive current resonance converter, control circuit, protective circuit etc.Control IC 2 is the general-purpose simulation IC (integrated circuit) that have bipolar transistor in it.
Control IC 2 is by being input to the direct voltage work of power input Vcc.By starting resistance, rectification and smooth voltage Ei are input to power input Vcc as starting voltage.When startup power supply, be input to the starting voltage starting control IC 2 of power input Vcc.
As the terminal that is used for initiating signal (grid voltage) is outputed to switching device, control IC 2 has two drive signal output VGH and VGL.
Drive signal output VGH output is used for the initiating signal of switch drive upper switches device.Drive signal output VGL output is used for the initiating signal of switch drive lower device.
In this case, drive signal output VGH is connected to the grid of upper switches device Q1.Drive signal output VGL is connected to the grid of lower device Q2.
Therefore, the grid of switching device Q1 is applied the top drive signal of drive signal output VGH output.The grid of switching device Q2 is applied the bottom drive signal of drive signal output VGL output.
Although this is not shown, boostrap circuit can be connected to control IC 2 as external circuit.This boostrap circuit makes the level of the top drive signal of drive signal output VGH output become the correctly level of driving switch device Q1.
Utilize internal oscillator circuit, control IC 2 produces the oscillator signal that requires frequency.Then, the oscillator signal that utilizes oscillating circuit to produce, control IC 2 produces top drive signal and bottom drive signal.Between mutually, have 180 ° of relations that differ, produce top drive signal and bottom drive signal.Then, control IC 2 is exported the top drive signal from drive signal output VGH, and from drive signal output VGL output bottom drive signal.
Respectively switching device Q1 and Q2 are applied top drive signal and bottom drive signal.Be in the H level period in drive signal, the grid voltage of switching device Q1 and Q2 is higher than gate threshold, and therefore, switching device Q1 and Q2 are in conducting state.Be in the L level period in drive signal, the grid voltage of switching device Q1 and Q2 is lower than gate threshold, and therefore, switching device Q1 and Q2 are in off-state.Therefore, in the time of switching device Q1 and Q2 alternate conduction/disconnection, with frequency switching driving switch device Q1 and the Q2 that requires.
Isolated variable transformer PIT is set, so that the output of the switch of switching device Q1 and Q2 is sent to primary side from primary side.
In this case, by primary side series resonance capacitor C1, the end of the elementary winding N1 of isolated variable transformer PIT is connected to being connected between switching device Q1 and the switching device Q2 (switch output point).The other end of elementary winding N1 is connected to the ground of primary side.
The leakage inductance of the electric capacity of series resonance capacitor C1 and elementary winding N1 (L1) forms the primary side series resonant circuit.This primary side series resonant circuit has been applied in the switch output of switching device Q1 and Q2, therefore, can carry out resonant operation.Therefore, the primary side series resonant circuit will comprise that the operational transformation of the switching circuit of switching device Q1 and Q2 is the operation of current resonance formula.
Therefore, utilize primary side series resonant circuit (L1-C1), the primary side switch converter in the circuit shown in Figure 27 is realized the operation of current resonance formula, and utilizes above-mentioned part voltage resonant circuit, realizes part voltage resonance operation (Cp//L1).
That is, the power circuit shown in this figure adopts the form of complex resonance converter, in this complex resonance converter, is used to the resonant circuit and the combination of another resonant circuit that make the primary side switch converter become controlled resonant converter.
Secondary winding N2 is wrapped on the primary side of isolated variable transformer PIT.
In this case, N2 is provided with centre cap to secondary winding, and this centre cap is connected to primary side ground.The full-wave rectifying circuit that comprises rectifier diode D01 and D02 and smmothing capacitor C0 is connected to secondary winding N2.Therefore, utilize the voltage at smmothing capacitor C0 two ends to obtain primary side VD E0.Primary side VD E0 is applied to the unshowned load-side of this figure, and its branch also is input to control circuit 1 as detecting voltage.
As control output, the control input end Vc that electric current that the level that control circuit 1 is input to the primary side VD E0 of control circuit 1 with its level basis changes or voltage are applied to control IC 2.For example, according to the control output that is input to control input end Vc, control IC 2 changes the frequency of oscillator signals, will be from the frequency of the drive signal of drive signal output VGH and VGL output thereby change.Therefore, can variable control switch device Q1 and the switching frequency of Q2.By such change switching frequency, the level of primary side VD E01 is controlled to be constant.That is it is stable, to utilize the switching frequency control system to realize.
Figure 28 utilizes solid line to illustrate for power circuit shown in Figure 27, when AC-input voltage VAC=100V, in the load variations scope of bearing power Po=150W to 0W, the characteristic curve of the level of power factor PF, power conversion efficiency η AC → DC and rectification and smooth voltage Ei (DC input voitage).
In order to compare, utilize to be shown in dotted line power circuit shown in Figure 27 and not have power factor to improve characteristic curve under the configuring condition.That is, utilize the characteristic curve be shown in dotted line when the circuit from electric main AC omits the parts of inductance L pch of power choke PCH.
Figure 29 illustrates for power circuit shown in Figure 27, when bearing power Po=150W, in the voltage level change scope of AC-input voltage VAC=80V to 120V, the characteristic curve of power factor PF, rectification and smooth voltage Ei and power conversion efficiency η AC → DC.
In order to obtain Figure 28 and experimental result shown in Figure 29, the each several part of following selection power circuit shown in Figure 27.
Power choke PCH Lpch=10mH
Isolated variable transformer PIT:EER 35 ferrite cores, the gap length of 1mm
Elementary winding N1=25T
Secondary winding N2:23T+23T, its centre cap is as the dividing potential drop position
Primary side series resonance capacitor C1=0.082 μ F
Partial resonance capacitor Cp=680pF
Following change presents the each several part of the characteristic power circuit that is shown in dotted line shown in Figure 28, forms this power circuit by omit power choke PCH (inductance L pch) from circuit shown in Figure 27.
Isolated variable transformer PIT:EER 35 ferrite cores, the gap length of 1mm
Elementary winding N1=31T
Secondary winding N2:23T+23T, its centre cap is as the dividing potential drop position
Primary side series resonance capacitor C1=0.068 μ F
Partial resonance capacitor Cp=680pF
As shown in figure 28, utilize solid line and the power conversion efficiency η AC → DC that is shown in dotted line all to trend towards raising with the rising of bearing power.When bearing power Po=150W, characteristic curve of the power conversion efficiency of the circuit shown in Figure 27 of insertion inductance L pch reaches maximum η AC → DC=87.5% in it, utilizes solid line that this characteristic curve is shown.
Along with the increase of load, the rectification and the smooth voltage Ei that utilize solid line and dotted line to represent all slowly reduce.For the variation of bearing power Po=0W → 150W, the characteristic curve of rectification and smooth voltage Ei shows the variation of Ei=134V → 115V when inserting inductance L pch, utilizes solid line that this characteristic curve is shown.
Along with the rising of bearing power, power factor PF also raises, and at bearing power Po=75W or when higher, power factor PF is smooth basically.When bearing power Po=150W, power factor PF=0.75.
In addition, according to Figure 29, for the variation of AC-input voltage VAC, power factor PF is about 0.75 constant.Along with the rising of AC-input voltage VAC, power conversion efficiency η AC → DC trends towards slow rising.Rectification and the smooth voltage Ei rising that is directly proportional with AC-input voltage VAC basically.
Figure 30 illustrates in order to utilize the choke input system to improve another example of the complex resonance converter of power factor configuration.Power circuit shown in this figure can satisfy condition [bearing power Po=250W or higher, and AC-input voltage VAC=100V standard].Carry one in passing, in the figure, utilize same Ref. No. represent with Figure 27 in identical part, therefore, omit explanation they.
Power circuit shown in this figure satisfies the heavy condition of load of duty ratio power circuit shown in Figure 27.Therefore, voltage doubling rectifing circuit is set as the rectification and the smoothing circuit that are used to produce rectification and smooth voltage Ei.In this case, be connected to electric main AC, form voltage doubling rectifing circuit by two rectifier diode Dia that will connect mutually and Dib and two smmothing capacitor Ci1 and Ci2, as shown in the drawing.
AC-input voltage VAC is applied to this voltage doubling rectifing circuit, and this voltage doubling rectifing circuit carries out rectification and smooth operation, thereby produces the rectification and the smooth voltage Ei of the twice of the level that is equivalent to AC-input voltage VAC at the series circuit two ends of smmothing capacitor Ci1-Ci2.
Rectification of Chan Shenging and smooth voltage Ei are applied to primary side switch converter on the following stages as DC input voitage like this, and then, this primary side switch converter carries out switching manipulation.
Figure 31 utilizes solid line to illustrate for power circuit shown in Figure 30, in the load variations scope of bearing power Po=300W to 0W, the characteristic curve of the level of power factor PF, power conversion efficiency η AC → DC and rectification and smooth voltage Ei (DC input voitage).
In order to compare, also utilize in the figure to be shown in dotted line the characteristic curve that power circuit shown in Figure 30 does not have (not having under power choke PCH (inductance L pch) situation) under the power factor improvement configuring condition.
When Figure 32 is illustrated in bearing power Po=300W, in the excursion of AC-input voltage VAC=80V to 120V, the characteristic curve of power factor PF, rectification and smooth voltage Ei and power conversion efficiency η AC → DC.
In order to obtain Figure 31 and experimental result shown in Figure 32, the each several part of following selection power circuit shown in Figure 30.
Power choke PCH Lpch=5mH
Isolated variable transformer PIT:EER 35 ferrite cores, the gap length of 1mm
Elementary winding N1=28T
Secondary winding N2:25T+25T, its centre cap is as the dividing potential drop position
Primary side series resonance capacitor C1=0.039 μ F
Partial resonance capacitor Cp=680pF
Following change is by omitting the power circuit that power choke PCH (inductance L pch) forms from circuit shown in Figure 30.The power circuit of Xing Chenging presents the characteristic curve that is shown in dotted line shown in Figure 31 like this.
Isolated variable transformer PIT:EER42 ferrite core, the gap length of 1mm
Elementary winding N1=32T
Secondary winding N2:25T
Primary side series resonance capacitor C1=0.033 μ F
Partial resonance capacitor Cp=680pF
As shown in figure 31, utilizing solid line and the power conversion efficiency η AC → DC that is shown in dotted line all is the constants that are positioned at bearing power Po=100W or higher scope basically.When bearing power Po=300W, the power conversion efficiency characteristic curve that inserts the circuit shown in Figure 30 of inductance L pch in it illustrates η AC → DC=91.1%, utilizes solid line that this characteristic curve is shown.
Along with the increase of load, utilize solid line and the rectification that is shown in dotted line and smooth voltage Ei all slowly to reduce.For the variation of bearing power Po=0W → 300W, the characteristic curve of rectification and smooth voltage Ei shows the variation of Ei=264V → 244V when inserting inductance L pch, utilizes solid line that this characteristic curve is shown.
Along with the rising of bearing power, power factor PF also trends towards raising.When bearing power Po=300W, power factor PF=0.75.
In addition,, when power factor PF slowly reduces along with the rising of AC-input voltage, we can say that for the variation of AC-input voltage VAC, for the gradient of this degree, power factor PF is about 0.75 constant according to Figure 32.Along with the rising of AC-input voltage VAC, power conversion efficiency η AC → DC trends towards slow rising.Rectification and the smooth voltage Ei rising that is directly proportional with AC-input voltage VAC basically.
Therefore, as mentioned above, utilize the choke input system, Figure 27 and power circuit shown in Figure 30 improve power factor.Therefore, for example can obtain to satisfy the value of power factor PF of the supply harmonic distortion adjusted value of color TV set at sufficiently high level.
Yet there is following problem in the power circuit with Figure 27 and configuration shown in Figure 30.
Utilize for example silicon steel plate core and copper cash winding to form to be arranged on the power choke PCH in Figure 27 and the power circuit shown in Figure 30 in order to improve power factor.Therefore, there is iron loss in iron core, and has the copper loss of the resistance generation of copper cash, therefore, has correspondingly increased the power loss of power choke PCH part.
In addition, the inductive component of choke and resistive component cause AC-input voltage VAC to produce pressure drop.Therefore, also reduced the DC input voitage (rectification and smooth voltage Ei) that obtains by rectification AC-input voltage VAC.
Therefore, reduced the power conversion efficiency of utilization, but also increased ac input power the complex resonance converter of the DC input voitage work of its input.
For power circuit shown in Figure 27, for example, make power factor PF bring up to from 0.55 at 0.75 o'clock by inserting power choke PCH, gross power conversion efficiency η AC → DC is reduced to 87.5% from 90.6%, reduces by 3.1 percentage points.Ac input power Pin is elevated to 171.4W from 165.5W, rising 5.9W.Carry one in passing, rectification and smooth voltage Ei are reduced to 115V from 134V, reduce 19V.
For power circuit shown in Figure 30, by inserting power choke PCH, power factor PF brings up to 0.75 from 0.60.Yet power conversion efficiency η AC → DC is reduced to 91.1% from 92.8%, reduces by 1.7 percentage points.Ac input power Pin is elevated to 326.0W from 320W, rising 6.0W.Rectification and smooth voltage Ei are reduced to 244V from 264V, reduce 20V.
In addition, in the each several part that constitutes power circuit, the big and Heavy Weight of the size of power choke PCH.Therefore, power choke PCH occupies very large area on the circuit board, therefore, has increased the weight of circuit board.
In the time will reducing the leakage flux of power choke PCH as much as possible, iron core is shaped to trapezoidal shape (E-E shape or E-I shape).For example, in power circuit shown in Figure 27, weight and circuit board area occupied with power choke PCH of this trapezoidal shape iron core are respectively 153g and 11cm 2, and in power circuit shown in Figure 30, they are respectively 240g and 19cm 2
In addition, as mentioned above, power choke PCH produces more leakage flux.According to such as the layout of each several part, the situations such as quantity of leakage flux, the leakage flux of power choke PCH may have influence on load-side.In this case, additional part such as magnetic screen etc., therefore the measure as the leakage flux that is used to suppress power choke PCH radiation, has increased the size and the weight of circuit board.
Therefore, for the problem of utilizing the choke input system to improve the power circuit of power factor configuration is because insert that the power choke causes that power conversion efficiency reduces, the size of power circuit and weight increases and cost to increase be inevitable.
Summary of the invention
Therefore, in view of the above problems, following structure is according to switching power circuit of the present invention.
Switching power circuit comprises: rectification and smoothing apparatus, be used to produce rectification and smooth voltage, and this rectification and smoothing apparatus comprise the rectifying device that is used for the rectification AC-input voltage and are used for the smmothing capacitor of the voltage of level and smooth rectifying device rectification; Switching device is provided rectification and smooth voltage that rectification and smoothing apparatus produce, and is used to carry out switching manipulation, utilizes two switching devices by semibridge system coupling coupling to constitute this switching device; And driving mechanism for switch, be used for these two switching devices of switch drive, so that these two switching devices replace on/off.
This switching power circuit also comprises: isolated variable transformer, form this isolated variable transformer by twining elementary winding and secondary winding, described elementary winding is provided the switch output of the switching manipulation acquisition of described switching device, when obtaining switch output, elementary winding responds to alternating voltage on the described secondary winding, and this isolated variable transformer forms the gap of predetermined length, with the loose coupling state of the coupling coefficient that obtains to have requirement; And primary side series resonant circuit, be provided the switch output of switching device output, and be the operation of current resonance formula with the operational transformation of switching device, utilize the leakage inductance component of elementary winding at least and form this primary side series resonant circuit with the electric capacity of the primary side series resonance capacitor of this elementary windings in series.
This switching power circuit also comprises: the VD generating apparatus, be configured, and with by being received in the alternating voltage that this secondary winding obtains and carrying out the rectification operation, produce the primary side VD; And the constant voltage control device, be configured, with by level, control the switching frequency that this driving mechanism for switch changes this switching device according to this primary side VD, described primary side VD is carried out constant voltage control.
Gou Zao switching power circuit also comprises like this: power factor is improved transformer, and by twining: power factor is improved elementary winding, the insertion of connecting with the primary side series resonant circuit; And power factor improvement secondary winding, insert the rectification and level and smooth path that form rectification and smoothing apparatus, form this power factor improvement transformer.Improve elementary winding according to power factor and improve the alternating voltage of responding on the secondary winding in power factor, the rectifying device of rectification and smoothing apparatus is carried out switching manipulation.
In addition, the another kind of switching power circuit of following structure.
This switching power circuit comprises: rectification and smoothing apparatus comprise: a plurality of low frequency rectifying devices are used for respectively the positive period/negative period in AC-input voltage, the rectification AC-input voltage; And smmothing capacitor, be used for the voltage of level and smooth low frequency rectifying device rectification; Switching device is provided rectification and smooth voltage that rectification and smoothing apparatus produce, and is used to carry out switching manipulation, utilizes two switching devices by semibridge system coupling coupling to constitute switching device; Driving mechanism for switch is used for these two switching devices of switch drive, so that these two switching devices replace on/off.
This switching power circuit also comprises: isolated variable transformer, form this isolated variable transformer by twining elementary winding and secondary winding, described elementary winding is provided the switch output of the switching manipulation acquisition of described switching device, when obtaining switch output, elementary winding responds to alternating voltage on the described secondary winding, and this isolated variable transformer forms the gap of predetermined length, with the loose coupling state of the coupling coefficient that obtains to have requirement.
This switching power circuit also comprises: the primary side series resonant circuit, be provided the switch output of switching device output, and be the operation of current resonance formula with the operational transformation of switching device, utilize the leakage inductance component of elementary winding at least and form this primary side series resonant circuit with the electric capacity of the primary side series resonance capacitor of this elementary windings in series;
This switching power circuit also comprises: the VD generating apparatus, be configured, and with by being received in the alternating voltage that this secondary winding obtains and carrying out the rectification operation, produce the primary side VD; And the constant voltage control device, be configured, with by level, control the switching frequency that this driving mechanism for switch changes this switching device according to this primary side VD, the primary side VD is carried out constant voltage control.
Gou Zao switching power circuit also comprises like this: power factor is improved transformer, and by twining: power factor is improved elementary winding, the insertion of connecting with the primary side series resonant circuit; And power factor improvement secondary winding, in parallel with the formation rectification with the predetermined rectified current path of smoothing apparatus, form this power factor and improve transformer; And a plurality of high-frequency rectification devices, improving secondary winding with power factor connects, be used to utilize power factor to improve elementary winding, improve the positive period/negative period of the alternating voltage of secondary winding induction respectively in power factor, carry out switching manipulation, compare with the frequency of AC-input voltage, described alternating voltage has high frequency.
In addition, the another kind of switching power circuit of following structure.
Switching power circuit comprises:
Rectification and smoothing apparatus comprise: a plurality of rectifying devices are used for respectively the positive period/negative period in AC-input voltage, the rectification AC-input voltage; And smmothing capacitor, be used for the voltage of level and smooth rectifying device rectification; Switching device is provided rectification and smooth voltage that rectification and smoothing apparatus produce, and is used to carry out switching manipulation, utilizes two switching devices by semibridge system coupling coupling to constitute this switching device; And driving mechanism for switch, be used for these two switching devices of switch drive, so that these two switching devices replace on/off;
This switching power circuit also comprises: isolated variable transformer, form this isolated variable transformer by twining elementary winding and secondary winding, described elementary winding is provided the switch output of the switching manipulation acquisition of described switching device, when obtaining switch output, elementary winding responds to alternating voltage on the described secondary winding, and this isolated variable transformer forms the gap of predetermined length, with the loose coupling state of the coupling coefficient that obtains to have requirement;
This switching power circuit also comprises: the primary side series resonant circuit, be provided the switch output of switching device output, and be the operation of current resonance formula with the operational transformation of switching device, utilize the leakage inductance component of elementary winding at least and form this primary side series resonant circuit with the electric capacity of the primary side series resonance capacitor of this elementary windings in series.
This switching power circuit also comprises: the VD generating apparatus, be configured to by being received in the alternating voltage that this secondary winding obtains and carrying out the rectification operation, and produce the primary side VD; And the constant voltage control device, be configured, with by level, control the switching frequency that this driving mechanism for switch changes this switching device according to this primary side VD, the primary side VD is carried out constant voltage control.
Gou Zao switching power circuit also comprises like this: power factor is improved transformer, and by twining: power factor is improved elementary winding, the insertion of connecting with this primary side series resonant circuit; And power factor improvement secondary winding, in parallel with the formation rectification with the predetermined rectified current path of smoothing apparatus, form this power factor and improve transformer.Improve elementary winding according to power factor and improve the alternating voltage of responding on the secondary winding in power factor, the rectifying device of this rectification and smoothing apparatus is carried out switching manipulation.
The switching power circuit that has above-mentioned composition according to the present invention respectively has the current resonance converter of semibridge system coupled system in primary side, as the complex resonance converter.In order to improve power factor, utilize power factor to improve transformer, the switched voltage output of complex resonance converter is fed back to rectification and level and smooth path, and utilize rectifier diode to interrupt rectified current, thereby increase the angle of flow that exchanges input current, to improve power factor.
Therefore, have according to the present invention switching power circuit that power factor improves function not needs adopt the so-called choke input system of the power choke being inserted the electric main circuit.Therefore, compare with utilizing choke input system improvement power factor, switching power circuit according to the present invention has the effect of remarkable improvement power factor.
Description of drawings
Fig. 1 is the circuit diagram according to the configuration example of the power circuit of first embodiment of the invention;
Fig. 2 is the cutaway view of the configuration example of loosely coupled transformer;
Fig. 3 A, 3B, 3C, 3D, 3E and 3F illustrated based on the electric main cycle, according to the oscillogram of the work of each major part of the power circuit of first embodiment;
Fig. 4 is on the power circuit that is illustrated in according to first embodiment, and power factor, power conversion efficiency and rectification and smooth voltage level are for the characteristic curve of load variations;
Fig. 5 is on the power circuit that is illustrated in according to first embodiment, and power factor, power conversion efficiency and rectification and smooth voltage level are for the characteristic curve of the variation of AC-input voltage;
Fig. 6 is the circuit diagram that illustrates according to the configuration example of the power circuit of second embodiment;
Fig. 7 is the circuit diagram that illustrates according to the configuration example of the power circuit of the 3rd embodiment;
Fig. 8 A, 8B, 8C, 8D and 8E illustrated based on the electric main cycle, according to the oscillogram of the work of each major part of the power circuit of the 3rd embodiment;
Fig. 9 is on the power circuit that is illustrated in according to the 3rd embodiment, and power factor, power conversion efficiency and rectification and smooth voltage level are for the characteristic curve of load variations;
Figure 10 is on the power circuit that is illustrated in according to the 3rd embodiment, and power factor, power conversion efficiency and rectification and smooth voltage level are for the characteristic curve of the variation of AC-input voltage;
Figure 11 is the circuit diagram that illustrates according to the configuration example of the power circuit of the 4th embodiment;
Figure 12 is the circuit diagram that illustrates according to the configuration example of the power circuit of the 5th embodiment;
Figure 13 is the cutaway view according to the configuration example of the isolated variable transformer of this embodiment;
Figure 14 be circuit shown in Figure 12 equivalent circuit diagram (for coupling coefficient be 0.8 or lower isolated variable transformer);
Figure 15 be circuit shown in Figure 12 equivalent circuit diagram (for coupling coefficient be 0.9 or higher isolated variable transformer);
Figure 16 is on the power circuit that is illustrated in according to the 5th embodiment, and power factor, power conversion efficiency and rectification and smooth voltage level are for the characteristic curve of load variations;
Figure 17 is the circuit diagram that illustrates according to the configuration example of the power circuit of the 6th embodiment;
Figure 18 is the circuit diagram that illustrates according to the modification of the power circuit of the 6th embodiment;
Figure 19 is the circuit diagram that illustrates according to the modification of the power circuit of the 6th embodiment;
Figure 20 be circuit shown in Figure 17 equivalent circuit diagram (for coupling coefficient be 0.8 or lower isolated variable transformer);
Figure 21 be circuit shown in Figure 17 equivalent circuit diagram (for coupling coefficient be 0.9 or higher isolated variable transformer);
Figure 22 is on the power circuit that is illustrated in according to the 6th embodiment, and power factor, power conversion efficiency and rectification and smooth voltage level are for the characteristic curve of load variations;
Figure 23 is the circuit diagram that illustrates according to the configuration example of the power circuit of the 7th embodiment;
Figure 24 is the circuit diagram that illustrates according to the modification of the power circuit of the 7th embodiment;
Figure 25 is on the power circuit that is illustrated in according to the 7th embodiment, and power factor, power conversion efficiency and rectification and smooth voltage level are for the characteristic curve (VAC=100V) of load variations;
Figure 26 is on the power circuit that is illustrated in according to the 7th embodiment, and power factor, power conversion efficiency and rectification and smooth voltage level are for the characteristic curve (VAC=230V) of load variations;
Figure 27 is the circuit diagram that the configuration example of correlation technique power circuit is shown;
Figure 28 is illustrated on the power circuit shown in Figure 27, and power factor, power conversion efficiency and rectification and smooth voltage level are for the characteristic curve of load variations;
Figure 29 is illustrated on the power circuit shown in Figure 27, the characteristic curve that power factor, power conversion efficiency and rectification and smooth voltage level change for AC-input voltage;
Figure 30 is the circuit diagram that another configuration example of correlation technique power circuit is shown;
Figure 31 is illustrated on the power circuit shown in Figure 30, and power factor, power conversion efficiency and rectification and smooth voltage level are for the characteristic curve of load variations;
Figure 32 is illustrated on the power circuit shown in Figure 27, the characteristic curve that power factor, power conversion efficiency and rectification and smooth voltage level change for AC-input voltage.
Embodiment
Fig. 1 is the circuit diagram according to the configuration example of the switching power circuit of first embodiment of the invention.Power circuit shown in this figure satisfies so-called single scope (range) AC-input voltage VAC=100V standard (system) and bearing power Po=150W or higher condition.That is, power circuit shown in this figure and above-mentioned power circuit shown in Figure 27 satisfy same loading condition.
At first, the power circuit shown in this figure has common-mode noise filter, and this common-mode noise filter is by being connected to electric main AC formation with common mode choke CMC and a cross capacitor CL.For example, common-mode noise filter suppresses to be sent to from the switch converters side noise of electric main AC.
Then, adopt the power factor of the rectification circuit system formation that wherein utilization is comprised within it to improve the configuration that circuit 3 is connected to electric main AC according to power circuit of the present invention.As shown in the drawing, power factor is improved circuit 3 and is comprised bridge rectifier Di, smmothing capacitor Ci, filtering capacitor CN and loosely coupled transformer VFT (power factor improvement transformer).
By the secondary winding N12 of the loosely coupled transformer VFT that connects with the electrode input end of bridge rectifier Di, the electrode input end of bridge rectifier Di is connected to the anodal circuit of electric main AC.The negative input of bridge rectifier Di is connected to the negative pole circuit of electric main AC.
The cathode output end of bridge rectifier Di is connected to the positive terminal of smmothing capacitor Ci.The negative pole end of smmothing capacitor Ci is connected to primary side ground.The cathode output end of bridge rectifier Di is connected to primary side ground.
Improve the operation of the rectification circuit system on the circuit 3 as the power factor of such formation, carry out so-called full-wave rectification operation, wherein the AC-input voltage VAC that provides at electric main AC be just/each negative cycle, the rectification output of bridge rectifier Di rectification is charged to smmothing capacitor Ci.That is, the basic configuration of rectification circuit system is the full-wave rectifying circuit that comprises one group of bridge rectifier and one group of smmothing capacitor.At smmothing capacitor Ci two ends, the rectification of full-wave rectifying circuit operation produces rectification and smooth voltage Ei, and the level of this rectification and smooth voltage Ei equals AC-input voltage VGA and multiply by 1 level.
In addition, select fast quick-recovery type diode to improve each rectifier diode (rectifier cell) Da to Dd of the bridge rectifier Di in the circuit 3 as forming power factor respectively.Rectifier diode Da to Dd is set like this, with operation as the improvement power factor, switch (switch) rectified current, as described below.
In addition, power circuit according to the present invention adopts the wherein circuit arrangement of the anodal circuit of the secondary winding N12 insertion electric main AC of loosely coupled transformer VFT.This means that system connects with rectification circuit, insert the secondary winding N12 of loosely coupled transformer VFT.As a result, the operation that acquisition increases the angle of flow of the rectified current that flows through the rectification circuit system improves power factor like this.Carry one in passing, will illustrate that below the power factor of power factor improvement circuit 3 is improved operation.
Fig. 2 illustrates the configuration example of loosely coupled transformer VFT.
As shown in the drawing, loosely coupled transformer VFT has E-E shape iron core, and this E-E shape iron core is by in the magnetic post (magnetic leg) of the CR1 unshakable in one's determination mode facing to the magnetic post of CR2 unshakable in one's determination, makes the E shape CR1 unshakable in one's determination of Ferrite Material and CR2 combine formation.
Bobbin B is set, and this bobbin B utilizes resin forming for wherein primary side winding part and primary side winding part are disconnected from each other so that independently shape formation mutually.Elementary winding N11 is wrapped on the winding part of bobbin B.Secondary winding N12 is wrapped on another winding part of bobbin B.Therefore, the bobbin B that has twined elementary winding and secondary winding is installed on the above-mentioned E-E shape iron core (CR1 and CR2).On variant winding zone, primary side winding and primary side winding are wrapped on the center magnetic post of E-E shape iron core.Therefore, obtained the overall structure of loosely coupled transformer VFT.
In addition, form the clearance G that requires gap length in the bonding part of center magnetic post.Thereby obtain to require the loose coupling state of coupling coefficient.In this first embodiment, and among second, third and the 4th embodiment that will be described later, for example, gap length is about 1.5mm, and coupling coefficient is 0.75 or littler.
The switch converters of working when receiving rectification and smooth voltage Ei as DC input voitage among Fig. 1 adopts the structure of complex resonance converter, in this complex resonance converter, in this case, in primary side, the basic configuration to the current resonance converter is provided with a part voltage resonant circuit at least.
In this case, as shown in the drawing, utilize semibridge system to connect, will be connected to each other together by two switching device Q1 (top) and the Q2 (bottom) that MOS-FET constitutes.Between drain electrode-source electrode of switching device Q1 and Q2, damper diode DD1 and DD2 are in parallel with switching device Q1 and Q2 respectively with the direction shown in this figure.
Between drain electrode-source electrode of switching device Q2, partial resonance capacitor Cp is in parallel with switching device Q2.The electric capacity of partial resonance capacitor Cp and the leakage inductance L1 of elementary winding N1 form antiresonant circuit (part voltage resonant circuit).Then, obtain the operation of part voltage resonance, in this part voltage resonance operation, only when switching device Q1 and Q2 are disconnected, voltage resonance takes place.Carry one in passing, in this case, in fact the part voltage resonant circuit comprises the inductive component L11 of the elementary winding N11 of the loosely coupled transformer VFT that its winding is connected with the elementary winding N1 of isolated variable transformer PIT.
Control IC 2 comprises oscillating circuit, and this oscillating circuit utilizes drive current controlled resonant converters such as external drive system, control circuit, protective circuit.Control IC 2 is the general-purpose simulation IC (integrated circuit) that have bipolar transistor in it.
Direct voltage (18V) work of control IC 2 by being input to power input Vcc.By starting resistance RS, power input Vcc also links to each other with the circuit of rectification with smooth voltage Ei.When startup power supply, by starting resistance RS, the rectification of input and smooth voltage Ei starting control IC 2.By earth terminal E, control IC 2 is connected to primary side ground.
Control IC 2 has two drive signal output VGH and VGL, as the terminal that is used for drive signal (grid voltage) is outputed to switching device.
Drive signal output VGH output is used for the drive signal of switch drive upper switches device.Drive signal output VGL output is used for the drive signal of switch drive lower device.
The top drive signal of drive signal output VGH output is applied to the grid of switching device Q1.The bottom drive signal of drive signal output VGL output is applied to the grid of switching device Q2.
Carry one in passing, although this is not shown, in fact the boostrap circuit that is formed by peripheral exterior section is connected to control IC 2.This boostrap circuit makes the level of the drive signal that upper switches device Q1 is applied become the correctly level of driving switch device Q1.
In addition, switching device Q1 and Q2 in fact also link to each other with subelement such as resistance, gate-to-source resistance etc., but this is not shown.
Utilize internal oscillator circuit, control IC 2 produces the oscillator signal that requires frequency.As described below, according to the level of the control output that is input to terminal Vc from control circuit 1, oscillating circuit changes the frequency of oscillator signal.
Then, the oscillator signal that utilizes oscillating circuit to produce, control IC 2 produces top drive signal and bottom drive signal.Then, control IC 2 is exported the top drive signal from drive signal output VGH, and from drive signal output VGL output bottom drive signal.
In a switch periods, the waveform of top drive signal and bottom drive signal comprises the connection cycle (on period) of generation positive polarity rectangular pulse and the break period (offperiod) of 0V.Top drive signal and bottom drive signal all have above-mentioned waveform, and have 180 ° of outputs that differ mutually regularly.
This waveform is applied to switching device Q1 and Q2, thereby makes switching device Q1 and Q2 carry out switching manipulation, to replace on/off.
Carry one in passing, in the switching manipulation of reality, in the period of connecting switching device Q2 and in the period from cut-off switch device Q2 to connection switching device Q1, forming the short dead time (dead time) that switching device Q1 and Q2 all disconnect from cut-off switch device Q1.
This dead time is the period that two switching device Q1 and Q2 all disconnect.For in the operating process of part voltage resonance, when on/off switch device Q1 and Q2, guarantee charging and the discharge operation of partial resonance capacitor Cp at short notice, form this dead time.The duration in this dead time for example, can be set at control IC 2 ends.Control IC 2 changes will be from the pulse duty cycle of the drive signal of drive signal output VGH and VGL output, to form the period td of set duration.
Isolated variable transformer PIT is sent to primary side with the switch output of switching device Q1 and Q2.In this case, on isolated variable transformer PIT, twine elementary winding N1 and secondary winding N2.
In this case, by elementary winding N11 and the series resonance capacitor C1 of series connection loosely coupled transformer VFT, the end of the elementary winding N1 of isolating transformer PIT is connected to the tie point (switch output point) between the drain electrode of the source electrode of switching device Q1 and switching device Q2.The other end of elementary winding N1 is connected to primary side ground.
According to above-mentioned connection, the series circuit of the elementary winding N1 of the elementary winding N11-isolated variable transformer PIT of series resonance capacitor C1-loosely coupled transformer VFT is connected to the switch output point of switching device Q1 and Q2.
Therefore, in this case, the inductive component L11 of the elementary winding N11 of the electric capacity of series resonance capacitor C1, the leakage inductance L1 of isolated variable transformer PIT that comprises elementary winding N1 and loosely coupled transformer VFT forms the primary side series resonant circuit.This primary side series resonant circuit is connected to the switch output point, as mentioned above, thereby the switch output of switching device Q1 and Q2 is sent to this primary side series resonant circuit.According to the switch output that transmits, the primary side series resonant circuit is carried out resonant operation, thereby the operational transformation of primary side switch converter is the operation of current resonance formula.
Therefore, the primary side switch converter shown in this figure utilizes primary side series resonant circuit (C1-L11-L1) to realize the operation of current resonance formula, and (Cp//L1 (L11)) realizes the operation of part voltage resonance and utilize above-mentioned part voltage resonant circuit.
That is, the power circuit shown in this figure adopts the form that the resonant circuit wherein be used to make the primary side switch converter become controlled resonant converter and another resonant circuit make up.That is, the power circuit shown in this figure adopts the form of complex resonance converter.
Although do not describe with reference to the accompanying drawings, the structure of isolated variable transformer PIT has E-E shape iron core, and this E-E shape iron core is to form by being combined mutually by the E shape iron core that for example Ferrite Material constitutes.Isolated variable transformer PIT has primary side winding part and primary side winding part disconnected from each other.Elementary winding N1 that then will describe and secondary winding N2 are wrapped on the center magnetic post of E-E shape iron core.
In first embodiment and second, third and the 4th embodiment that will be described later, on the magnetic post of the center of E-E shape iron core, form the gap of about 1.0mm to 1.5mm.Therefore, obtain its coupling coefficient and be about 0.7 to 0.8 loose coupling state.
Secondary winding N2 is wrapped on the primary side of isolated variable transformer PIT.Secondary winding N2 induction is corresponding to the alternating voltage of the switch output that is sent to elementary winding N1.
N2 is provided with centre cap to secondary winding, and this centre cap is connected to primary side ground.The full-wave rectifying circuit that comprises rectifier diode D01 and D02 and smmothing capacitor C0 is connected to this secondary winding.Therefore, utilize the voltage at smmothing capacitor C0 two ends, obtain primary side VD E0.This primary side VD E0 is applied to the unshowned load-side of this figure, but also as detecting voltage, is input to control circuit 1 from its breakout, and explanation is done in the back.
As control output, control circuit 1 obtains electric current or the voltage of its level according to the level variation of primary side VD E0.This control outputs to the control end Vc of control IC 2.
Level according to the control output that is input to control end Vc, control IC 2 operations, with when alternately keeping the on/off drive signal, changing respectively under synchronous regime will be from drive signal output VGH and the top drive signal of VGL output and the frequency of bottom drive signal.
Therefore, can be according to the level (that is, the level of primary side VD) of the control output that is input to control end Vc, the switching frequency of variable control switch device Q1 and Q2.
When changing switching frequency, change the resonance impedance of primary side series resonant circuit.When like this changing resonance impedance, change the magnitude of current that the elementary winding N1 to the primary side series resonant circuit applies, but also change the power that is sent to primary side.Therefore, change the level of primary side VD E0.Therefore, realize constant voltage control.
Then, will the operation of the power factor improvement circuit 3 with above-mentioned configuration be described with reference to the oscillogram shown in figure 3A, 3B, 3C, 3D, 3E and the 3F.
For example, suppose the AC-input voltage VAC that has obtained to have the cycle shown in Fig. 3 A, the interchange input current IAC that flows into the rectified current path from electric main AC flows, so that be respectively positive polarity/negative polarity in positive period/negative period of AC-input voltage VAC, shown in Fig. 3 B.
The current potential V1 of utilization between the tie point between the end of the secondary winding N12 of filtering capacitor CN on the circuit of primary side ground and electric main AC and loosely coupled transformer VFT obtains the waveform shown in Fig. 3 C.
Utilize the electrode input end of bridge rectifier Di and the current potential V2 between the primary side ground, obtain the waveform shown in Fig. 3 E.
The switch output of primary side switch converter is sent to the elementary winding N11 of loosely coupled transformer VFT.On the secondary winding N12 of loosely coupled transformer VFT, correspondingly respond to alternating voltage.Since as top illustrated like that, the secondary winding N12 of loosely coupled transformer VFT insertion rectified current path, loosely coupled transformer have realized making the switched voltage output of primary side switch converter to feed back to the operation of rectified current path.
Fig. 3 C has at the period of the non-conduction period that exchanges input current IAC stack alternation waveform component thereon with current potential V1 shown in the 3E and V2, and is as shown in the drawing.This is because the Voltage Feedback of the switch of primary side switch converter output causes, as mentioned above.
Therefore, the electric current I 2 of secondary winding N12 that flows into loosely coupled transformer VFT from the circuit of electric main AC is mobile stablize the alternation waveform, shown in Fig. 3 F.Utilization has the fixed amplitude of 0 level at the center, and for corresponding to the conducting period that exchanges input current IAC, has the waveform of stack positive polarity rectified current I1 component thereon, obtains this electric current I 2.
At AC-input voltage VAC is respectively each period of positive polarity/negative polarity, in the maximum of current potential V1 shown in Fig. 3 C and near the time the minimum value, exist the level of current potential V1 to be higher than the period of rectification and smooth voltage Ei, in this period, the rectified current I1 shown in Fig. 3 D flows into smmothing capacitor Ci from bridge rectifier Di.
When rectified current flow through the fast quick-recovery type rectifier diode Da to Dd of each that constitute bridge rectifier Di, according to the alternating voltage of the secondary winding N12 induction of loosely coupled transformer VFT, these rectifier diodes were carried out switching manipulations.Therefore, the rectified current that flows through rectifier diode is interrupted, and makes rectified current I1 have the alternation waveform shown in Fig. 3 D.
In the positive period of AC-input voltage VAC, rectified current I1 is from the rectified current path of filtering capacitor CN by the negative pole circuit of rectifier diode Da → smmothing capacitor Ci → primary side ground → rectifier diode Dd → electric main of anodal circuit inflow secondary winding N12 → bridge rectifier Di of electric main AC.
In the negative period of AC-input voltage VAC, rectified current I1 flows into the rectified current path of rectifier diode Dc → smmothing capacitor Ci → primary side ground → rectifier diode Db → secondary winding N12 by the negative pole circuit of electric main AC from filtering capacitor CN.
Therefore, rectified current is interrupted, so that utilize fast quick-recovery type rectifier diode (Da to Dd) switch (swtich) rectified current, thereby even be lower than period of the level of rectification and smooth voltage Ei at the rectifier output voltage level, charging current still flows into smmothing capacitor Ci.
Therefore, exchange the waveform of the average waveform of input current, therefore, shown in Fig. 3 B, increase the angle of flow that exchanges input current IAC near AC-input voltage.By increasing the angle of flow that exchanges input current IAC, improve power factor.
Fig. 4 illustrates as the characteristic curve with power circuit of configuration shown in Figure 1, when AC-input voltage VAC=100V, for the variation of bearing power Po=0 to 150W, the variation of power conversion efficiency (η AC/DC), power factor PF and rectification and smooth voltage Ei.
Fig. 5 illustrates as the characteristic curve with power circuit of configuration shown in Figure 1, when bearing power Po=150W, for the variation of AC-input voltage VAC=85V to 120V, the variation of power conversion efficiency (η AC/DC), power factor PF and rectification and smooth voltage Ei.
Explanation is for reference for the constant that obtains the each several part of circuit shown in Fig. 4 and experimental result Fig. 1 shown in Figure 5.
Filtering capacitor CN=1 μ F
The elementary winding N1=32T of isolated variable transformer PIT
The secondary winding N2:23T+23T (circle) of isolated variable transformer PIT, its centre cap is as the dividing potential drop position
Primary side series resonance capacitor C1=0.068 μ F
Primary side partial resonance capacitor Cp=680pF
Loosely coupled transformer VFT:EE-28 ferrite core, gap length=1.5mm
The inductance L 11=75 μ H of elementary winding N11
The inductance L 12=50 μ H of elementary winding N12
Below will be according to Fig. 4 and Fig. 5, when bearing power Po=150W, the power circuit of power circuit shown in Figure 1 and correlation technique shown in Figure 27 is compared.Carry one in passing, although as description of Related Art Figure 27 and two kinds of power circuits shown in Figure 30, the satisfied identical circuit shown in Figure 27 of condition of the condition that will satisfy with its configuration and power circuit shown in Figure 1 is done contrast below.
At first, about power factor, the power factor PF=0.78 of circuit shown in Figure 1, this explanation is compared with the power factor PF=0.75 of power circuit shown in Figure 27, is improved.
About the power conversion efficiency (η AC/DC) of circuit shown in Figure 1, η AC/DC=90.6%, and for circuit shown in Figure 27, η AC/DC=87.5%.This explanation has improved 3.1 percentage points.Therefore, the ac input power Pin of circuit shown in Figure 27 is 171.4W, and the ac input power Pin of circuit shown in Figure 1 is 165.5W.This explanation has reduced 5.9W.This power conversion efficiency equals not insert the power conversion efficiency of the circuit arrangement shown in Figure 27 of power choke PCH (not improving power factor).
About the rectification of circuit shown in Figure 1 and the level of smooth voltage Ei, Ei=143V.For the circuit arrangement of the circuit shown in Figure 27 that does not insert power choke PCH (not improving power factor), Ei=134V.Therefore, present embodiment obtains high rectification of its level ratio 134V and smooth voltage Ei.By the Voltage Feedback amount of stack, increase rectification and smooth voltage Ei like this as the switch output of rectification and smooth voltage Ei.
In addition, in circuit shown in Figure 1, omit power choke PCH, and insert loosely coupled transformer VFT.
The weight of power choke PCH in the circuit shown in Figure 27 is 153g, and the circuit board area occupied is 11cm 2On the contrary, also have only 48g heavy even loosely coupled transformer VFT among Fig. 1 and filtering capacitor CN combine, this explanation reduce to circuit shown in Figure 27 power choke PCH weight 31%.In addition, the circuit board area occupied is 9cm 2, this explanation reduces to about 82%.
Therefore, compare with power circuit shown in Figure 27, improve function and can handle bearing power Po=150W or higher power circuit as having power factor, power circuit shown in Figure 1 has less size and lighter weight.
In addition, because omitted power choke PCH, so needn't consider of the influence of the leakage flux of power choke PCH generation to load-side.For example, so just do not need power choke PCH is provided with the magnetic screen sheet, therefore, also help to reduce the size and the weight of this circuit.
Fig. 6 illustrates the configuration example according to the switching power circuit of second embodiment of the invention.Power circuit shown in this figure also satisfies single scope AC-input voltage VAC=100V standard and bearing power Po=150W or higher condition.Carry one in passing, in the figure, utilize same Ref. No. to represent and the identical part of part among Fig. 1, therefore, omit explanation they.
At first, on the power circuit shown in this figure, parallel resonance capacitor C2 is in parallel with the secondary winding N2 of isolated variable transformer PIT.
The electric capacity of this parallel resonance capacitor C2 and the leakage inductance L2 of secondary winding N2 form the secondary lateral parallel resonant circuit.The electric capacity of selected parallel resonance capacitor C2 is between between the 1000pF to 3300pF.Capacitance according to actual selection, this secondary lateral parallel resonant circuit forms and is used for the operational transformation of the primary side rectification circuit voltage resonant circuit for the operation of voltage resonance formula perhaps is formed for obtaining the part voltage resonant circuit of part voltage resonance operation.
That is, also has resonant circuit as the complex resonance converter in primary side according to the power circuit of second embodiment.Therefore,, can realize more stable switching manipulation, and satisfy the more condition of heavy load by resonant circuit being set in primary side.
Improve circuit 3 with power factor shown in Figure 1 and compare, the power factor of power circuit shown in Figure 6 is improved circuit 3 and is had as additional fast quick-recovery type rectifier diode (high-frequency rectification element) D1, D2 and the D3 thereon of part.That is, in this case, the switch of the rectifier diode of bridge rectifier Di does not interrupt rectified current.As the diode that is used for the rectified current on the switching and rectifying current path, rectifier diode D1, D2 and D3 are set.In this case, the rectifier diode Da to Dd of bridge rectifier Di is (the low frequency rectifier cell) that recovers type at a slow speed, because rectifier diode Da to Dd switching and rectifying electric current not.
In this case, the electrode input end of bridge rectifier Di is directly connected to electric main AC.In addition, the electrode input end of bridge rectifier Di is from the secondary winding N12 of loosely coupled transformer VFT, be connected to the positive terminal of smmothing capacitor Ci by anode → negative electrode of rectifier diode D1, the electrode input end of this secondary winding N12 and bridge rectifier Di is connected in series.The negative electrode of rectifier diode D2 is connected to the anode of rectifier diode D1, and its anode is connected to primary side ground.
The cathode output end of bridge rectifier Di is connected to the positive terminal of smmothing capacitor Ci by anode → negative electrode of rectifier diode D3.
In this case, filtering capacitor CN is inserted between the positive terminal of the electrode input end of bridge rectifier Di and smmothing capacitor Ci (tie point between the anode of rectifier diode D1 and D3).Filtering capacitor CN forms the current path by the high fdrequency component of the mobile acquisition of switching and rectifying electric current, does explanation below.
The following describes above-mentioned power factor and improve the operation of circuit 3.
The interchange input current IAC that power factor is improved on the circuit 3 is branched to: the first rectified current I1 flows into the diode Da that constitutes bridge rectifier Di from the anodal circuit of electric main AC; And the second rectified current I2, flow into the secondary winding N12 of loosely coupled transformer VFT from the anodal circuit of electric main AC.
In the positive period of AC-input voltage VAC, the first rectified current I1 flows in the path of the negative pole circuit of anodal circuit → rectifier diode Da of electric main AC (bridge rectifier Di) → rectifier diode D3 → smmothing capacitor Ci → rectifier diode Dd (bridge rectifier Di) → electric main AC.
Flow the path of secondary winding N12 (loosely coupled transformer VFT) → rectifier diode D1 from the second rectified current I2 of electric main AC branch, then, flow into smmothing capacitor Ci.
In the negative period of AC-input voltage VAC, the first rectified current I1 flows in the path of the anodal circuit of negative pole circuit → rectifier diode Dc of electric main AC (bridge rectifier Di) → rectifier diode D3 → smmothing capacitor Ci → rectifier diode Db (bridge rectifier Di) → electric main AC.
The second rectified current I2 flows in the path of negative pole circuit → rectifier diode Dc of electric main AC (bridge rectifier Di) → rectifier diode D1 → smmothing capacitor Ci, then, its branch flows in the path of the anodal circuit of rectifier diode D2 → secondary winding N12 (loosely coupled transformer VFT) → electric main AC.
Improve on the circuit 3 in power factor, utilize the alternating voltage of the secondary winding N12 induction of loosely coupled transformer VFT, carry out the Voltage Feedback of switch output.Therefore, in the flow process of rectified current as mentioned above, the quick-recovery type rectifier diode D3 switch first rectified current I1 soon, and utilize fast quick-recovery type rectifier diode D1 and D2 (and D3) the switch second rectified current I2.Therefore, this rectified current forms the alternation waveform.
Carry one in passing, absorb the high-frequency current component that switch periods obtains as the alternation waveform, filtering capacitor CN being charged and discharge, thus the inhibition normal mode noise.
Thereby utilize fast quick-recovery type rectifier diode D1, D2 and this rectified current of D3 switch by such interruption rectified current, can increase the angle of flow that exchanges input current IAC, thereby improve power factor.
The same with power circuit shown in Figure 1, to compare with power circuit shown in Figure 27, the power circuit shown in Figure 6 with above-mentioned configuration can also improve power conversion efficiency, and reduces the size and the weight of circuit board.
For example, be inserted in the rectifier diode D3 work between the positive pole of the cathode output end of bridge rectifier Di and smmothing capacitor Ci,, and the rectified current near the peak level of AC-input voltage VAC passed through with the switching and rectifying electric current.Be controlled at the peak level of the rectified current of rectifier diode D1 and D2 side flow like this,, this peak level occur according to the peak value of AC-input voltage VAC.Therefore, can reduce switching loss and the association heat of rectifier diode D1 and D2.
Fig. 7 illustrates the circuit diagram according to the configuration example of the power circuit of the 3rd embodiment.Although the power circuit according to Fig. 1 and first and second embodiment shown in Figure 6 satisfies single scope AC-input voltage VAC=100V standard and bearing power Po=150W or higher condition, satisfy condition and the bearing power Po=250W or the higher different condition of identical single scope AC-input voltage VAC=100V standard according to the power circuit of the 3rd embodiment.Therefore, satisfiable loading condition is identical with the loading condition of power circuit shown in Figure 30.
Carry one in passing, in the figure, utilize same Ref. No. represent with Fig. 1 and Fig. 6 in the identical part of part, therefore, omit the similar part of explanation.
Improve the basic configuration of the rectification circuit system in the circuit 3 as being arranged on power factor, the power circuit shown in this figure has voltage doubling rectifing circuit.
Specifically, two smmothing capacitor Ci1-Ci2 of series connection mutually are set, and the series circuit parallel connection of smmothing capacitor Ci1 and Ci2 is inserted between the cathode output end and primary side ground of bridge rectifier Di.
The negative pole circuit of electric main AC is connected to the tie point between smmothing capacitor Ci1-Ci2.On the contrary, the negative input of bridge rectifier Di is connected to the electrode input end of same bridge rectifier Di, and therefore, on the rectified current path, the rectifier diode Da and the Dc that constitute bridge rectifier Di are in parallel mutually.
In this case, the rectifier diode Da to Dd of bridge rectifier Di is fast quick-recovery type, is used for the switching and rectifying electric current.
The rectification operation that utilization describes below, the voltage doubling rectifing circuit that forms produces the rectification and the smooth voltage Ei (DC input voitage) of the twice of the level that is equivalent to AC-input voltage VAC like this.Voltage doubling rectifing circuit raises the level of rectification and smooth voltage Ei, thereby for example satisfies the condition higher than the load of Fig. 1 and circuit shown in Figure 6.
To illustrate that the power factor of above-mentioned power factor improvement circuit 3 is improved operation with reference to the oscillogram shown in figure 8A, 8B, 8C, 8D and the 8E.Also will improve the operation explanation below and be included in the rectification operation that power factor is improved the voltage doubling rectifing circuit in the circuit 3 with the power factor that power factor is improved circuit 3.
Suppose that input has the AC-input voltage VAC in cycle shown in Fig. 8 A, current potential V1 forms sine wave shown in Fig. 8 C, this sine wave has maximum in the positive period of AC-input voltage VAC, and has the minimum value of 0V in the negative period of this AC-input voltage VAC, and is as shown in the drawing.This current potential V1 is the current potential between the tie point between the secondary winding N12 of the loosely coupled transformer VFT on the anodal circuit of primary side ground and filtering capacitor CN and electric main AC, the path that connection between the secondary winding N12 of loosely coupled transformer VFT on the anodal circuit of filtering capacitor CN and electric main AC is flow through as the second rectified current I2, as shown in the drawing.
The absolute value of AC-input voltage VAC be higher than current potential V1 shown in Fig. 8 C absolute value each just/the negative period in, according to exchanging input current IAC, the second rectified current I2 flows.Shown in Fig. 8 E, the second rectified current I2 flows with the alternation waveform shown in this figure, wherein in the period, has positive polarity/negative polarity in each positive polarity of AC-input voltage VAC period/negative polarity respectively.
At first, in the positive polarity period of AC-input voltage VAC, anodal circuit by electric main AC, the second rectified current I2 flows through the secondary winding N12 of loosely coupled transformer VFT from filtering capacitor CN, then, further flow through the parallel circuits of the rectifier diode Da//Dc of bridge rectifier Di.Then, behind the parallel circuits by rectifier diode Da//Dc, this electric current flows into positive terminal → negative pole end of smmothing capacitor Ci1, and as the first rectified current I1, then, further the negative pole circuit from electric main AC flows into filtering capacitor CN.
In the negative period of AC-input voltage VAC, second rectified current flows into positive terminal → negative pole end of smmothing capacitor Ci2 by the negative pole circuit of electric main AC from filtering capacitor CN, then, by primary side ground, further flow through the rectifier diode Db of bridge rectifier Di.Then, behind this rectifier diode Db, the second rectified current I2 passes through the secondary winding N12 inflow filtering capacitor CN of loosely coupled transformer VFT from the anodal circuit of electric main AC.
According to flowing of above-mentioned rectified current, as the rectification operation, in the positive polarity period of AC-input voltage VAC, smmothing capacitor Ci1 charging, therefore, obtain the level that its level equals AC-input voltage VAC at smmothing capacitor Ci1 and multiply by 1 rectification and smooth voltage.Equally, in the negative polarity period of AC-input voltage VAC, therefore smmothing capacitor Ci2 charging, obtains the level that its level equals AC-input voltage VAC at smmothing capacitor Ci2 and multiply by 1 rectification and smooth voltage.
Therefore, utilize the voltage at the series circuit two ends of smmothing capacitor Ci1-Ci2 to obtain to be equivalent to the rectification and the smooth voltage Ei of twice of the level of AC-input voltage VAC.That is, realize the voltage multiplying rectifier operation.
Carry one in passing, though only in the positive polarity period of AC-input voltage VAC, the second rectified current I2 is by the parallel circuits of rectifier diode (Da//Dc).This is because power circuit shown in Figure 7 is handled its duty ratio situation heavy according to the load of Fig. 1 and power circuit embodiment illustrated in fig. 6.That is, although along with the increase of load, the rectified current flow increases, and when the rectifier diode of rectified current by parallel connection, the magnitude of current that flows through rectifier diode reduces.Therefore, the corresponding load that reduces on the rectifier diode.
In addition, improve on the circuit 3 in power factor with sort circuit configuration, the secondary winding N12 of loosely coupled transformer VFT induction alternating voltage, therefore, the alternating voltage component of the switch periods that on the rectified current path, superposeed.That is, realized that switch outputs to the Voltage Feedback of rectified current path.The alternating voltage component of switch periods owing to superposeed is so the rectifier diode of bridge rectifier Di is realized the operation of switch (switching) rectified current.
That is, from above-mentioned rectified current path as can be seen, in the positive polarity period of AC-input voltage VAC, rectifier diode Da and Dc realize switch and the operation of interrupting rectified current.Therefore, shown in Fig. 8 D and Fig. 8 E, the first rectified current I1 and the second rectified current I2 flow through the rectified current path with the alternation waveform of switch periods.
In the negative polarity period of AC-input voltage VAC, realize switch and the operation of interrupting rectified current at rectifier diode Db.Therefore, shown in Fig. 8 E, this rectified current forms the alternation waveform that flows with the negative polarity direction.
As mentioned above, utilize the rectifier diode switching and rectifying electric current of bridge rectifier Di to increase the angle of flow that exchanges input current IAC like this, shown in Fig. 8 B, therefore, improved power factor.
Fig. 9 illustrates as the characteristic curve with power circuit of configuration shown in Figure 7, when AC-input voltage VAC=100V, for the variation of bearing power Po=0 to 300W, the variation of power conversion efficiency (η AC/DC), power factor PF and rectification and smooth voltage Ei.
Figure 10 illustrates as the characteristic curve with power circuit of configuration shown in Figure 7, when bearing power Po=300W, for the variation of AC-input voltage VAC=85V to 120V, the variation of power conversion efficiency (η AC/DC), power factor PF and rectification and smooth voltage Ei.
Explanation is for reference for the constant that obtains the each several part of circuit shown in Fig. 9 and experimental result Fig. 7 shown in Figure 10.
Filtering capacitor CN=1 μ F
The elementary winding N1=35T of isolated variable transformer PIT
The secondary winding N2:25T+25T (circle) of isolated variable transformer PIT, its centre cap is as the dividing potential drop position
Primary side series resonance capacitor C1=0.039 μ F
Primary side partial resonance capacitor Cp=680pF
Loosely coupled transformer VFT:EE-28 ferrite core, gap length=1.5mm
The inductance L 11=130 μ H of elementary winding N11
The inductance L 12=100 μ H of elementary winding N12
Below will be according to Fig. 9 and experimental result shown in Figure 10, under the loading condition of bearing power Po=300W, the circuit of power circuit shown in Figure 7 and correlation technique shown in Figure 30 is compared.
At first, about power factor, the power factor PF=0.80 of circuit shown in Figure 7, this explanation is compared with the power factor PF=0.75 of power circuit shown in Figure 30, is improved.
About the power conversion efficiency of circuit shown in Figure 7 (η AC → DC), η AC → DC=93.5%, and, η AC → DC=91.1% for circuit shown in Figure 30.This explanation has improved 2.4 percentage points.Therefore, the ac input power Pin of circuit shown in Figure 30 is 326.0W, and the ac input power Pin of circuit shown in Figure 7 is 317.5W.This explanation has reduced 8.5W.Compare with the circuit arrangement shown in Figure 30 of not inserting power choke PCH (not improving power factor), this power conversion efficiency further is improved.
About the rectification of circuit shown in Figure 7 and the level of smooth voltage Ei, Ei=269V.For the circuit arrangement of the circuit shown in Figure 30 that does not insert power choke PCH (not improving power factor), Ei=264V.Therefore, present embodiment obtains high rectification of its level ratio 264V and smooth voltage Ei.
In addition, in circuit shown in Figure 7,, compare, omitted power choke PCH, and be provided with loosely coupled transformer VFT with circuit shown in Figure 30 from the viewpoint of mounting portion.
In order to satisfy the condition of heavy load, the weight of the power choke PCH in the circuit shown in Figure 30 is 240g, and the circuit board area occupied is 19cm 2On the contrary, loosely coupled transformer VFT among Fig. 7 and the total weight of filtering capacitor CN are 48g, and the circuit board area occupied of loosely coupled transformer VFT is 9cm 2Therefore, this description weight reduces to about 31%.And the circuit board area occupied reduces to about 47%.
Therefore, compare with power circuit shown in Figure 30, improve function and can handle bearing power Po=250W or higher power circuit as having power factor, power circuit shown in Figure 7 also significantly reduces size and weight.
In addition, power circuit shown in Figure 7 does not also need to consider the influence to load-side of leakage flux that power choke PCH produces, and the measure of magnetic screen sheet etc. is set.
Figure 11 illustrates the configuration example according to the power circuit of fourth embodiment of the invention.With identical, also satisfy single scope AC-input voltage VAC=100V standard and bearing power Po=250W or higher condition according to the power circuit of fourth embodiment of the invention according to the power circuit of the 3rd embodiment shown in Figure 7.Carry one in passing, utilize same Ref. No. represent with Fig. 1, Fig. 6 and Fig. 7 in the identical part of part, therefore, omit explanation they.
At first, still on the power circuit shown in this figure, utilize the rectification circuit system that is arranged on the power factor improvement circuit 3 to form voltage doubling rectifing circuit, to handle bearing power Po=250W or higher situation.Rectification that obtains at the smmothing capacitor Ci1-Ci2 two ends of series connection mutually and the level of smooth voltage Ei are equivalent to the twice of AC-input voltage VAC.
Yet, select the rectifier diode of recovery type at a slow speed as the rectifier diode Da to Dd that constitutes bridge rectifier Di shown in Figure 11.That is, in this case, the rectifier diode of bridge rectifier Di is not by the switch interrupts rectified current.As the diode that is used for the rectified current on the switching and rectifying current path, provide rectifier diode D1 of recovery type at a slow speed and D2.
In this case, the electrode input end of bridge rectifier Di is connected to the anodal circuit of electric main AC and the tie point between the filtering capacitor CN.The electrode input end of bridge rectifier Di also is connected to the positive terminal of smmothing capacitor Ci1 by the secondary winding N12-rectifier diode D1 (anode → negative electrode) of loosely coupled transformer VFT.The anode of rectifier diode D2 is connected to primary side ground, and its negative electrode is connected to the negative electrode of rectifier diode D2.
In this case, the negative input of bridge rectifier Di is also connected to the electrode input end of same bridge rectifier Di, thereby forms the parallel circuits of rectifier diode Da//Dc on formed rectified current path, and explanation is done in the back.
Improve on the circuit 3 in the power factor that forms as mentioned above, rectified current in the positive polarity period of AC-input voltage VAC branches into: the first rectified current I1 component, from the path of the negative pole circuit of link tester over commutation diode Da → smmothing capacitor Ci1 → electric main AC of electric main AC; And the second rectified current I2 component, flow through the path of negative pole circuit → filtering capacitor CN of secondary winding N12 → rectifier diode D1 → smmothing capacitor Ci1 → electric main AC of loosely coupled transformer VFT.
In this case, although because rectifier diode Da does not carry out switch, the first rectified current I1 does not form the alternation waveform, but alternation waveform according to the secondary winding N12 of loosely coupled transformer VFT induction, rectifier diode D1 carries out switch, and therefore, the second rectified current I2 forms the alternation waveform.
On the contrary, in the negative polarity period of AC-input voltage VAC, this rectified current at first flows into smmothing capacitor Ci2 from the negative line terminal of electric main AC.After this, this rectified current branches into the path of anodal circuit → filtering capacitor CN of secondary winding N12 → electric main AC of the path of anodal circuit of rectifier diode Db → electric main AC and rectifier diode D2 → loosely coupled transformer VFT.In this case, the rectified current of inflow latter path is the second rectified current I2.
In addition, in this case, the rectified current that flows into the former path does not form the alternation waveform, because rectifier diode Db does not carry out switch.On the contrary, according to the alternation waveform of the secondary winding N12 of loosely coupled transformer VFT induction, rectifier diode D2 carries out switch, and therefore, the second rectified current I2 that flows into latter's path forms the alternation waveform.
Therefore, in each positive polarity period/negative polarity period that power factor shown in Figure 11 is improved AC-input voltage VAC on the circuit, form rectified current and be branched the parallel passage portion that flows thereby rectified current flows through the path of rectifier diode of requirement of bridge rectifier Di and path that rectified current flows through rectifier diode D1 of recovery type at a slow speed or D2.
Rectifier diode D1 or D2 switch flow into the rectified current of the path that is positioned at rectifier diode D1 of recovery type at a slow speed or D2 one side.Therefore, as mentioned above, the angle of flow that exchanges input current IAC increases, thereby improves power factor.
According to aforesaid rectified current, as the rectification operation, still in power circuit shown in Figure 1, in the positive polarity period of AC-input voltage VAC, smmothing capacitor Ci1 charging, and in the negative polarity period of AC-input voltage VAC, smmothing capacitor Ci2 charging.Therefore, obviously, still in this case, the rectification operation is the voltage multiplying rectifier operation, the operation of this voltage multiplying rectifier produces the rectification and the smooth voltage Ei of the twice of the level that is equivalent to AC-input voltage VAC, as the voltage at the series circuit two ends of smmothing capacitor Ci1-Ci2.
Identical with the situation of second embodiment shown in Figure 6, power circuit shown in Figure 11 has the parallel resonance capacitor C2 in parallel with the secondary winding N2 of isolated variable transformer PIT.
In addition, in this case, the electric capacity of parallel resonance capacitor C2 and the leakage inductance L2 of secondary winding N2 are formed for the operational transformation of the primary side rectification circuit voltage resonant circuit for the operation of voltage resonance formula perhaps is formed for obtaining the part voltage resonant circuit of part voltage resonance operation.
Carry one in passing, can on power circuit, this secondary-side voltage resonant circuit be set according to Fig. 1 and the first and the 3rd embodiment shown in Figure 7.In addition, for example, the primary side series resonant circuit (current resonance circuit) by making resonant capacitor connect with secondary winding N2 and form can be set.
Figure 12 illustrates the configuration according to the power circuit of fifth embodiment of the invention.
Power circuit according to fifth embodiment of the invention satisfies single scope electric main AC=200V standard and bearing power Po=250W or higher condition.Carry one in passing, utilize same Ref. No. represent with Fig. 1, Fig. 6, Fig. 7 and Figure 11 in the identical part of part, therefore, omit explanation they.
At first, the power circuit shown in this figure has Drive and Control Circuit 4.For example, be integrated into a circuit part, form this circuit by control circuit 1 and the control IC 2 that is provided with in will circuit diagram according to the power circuit of above-mentioned each embodiment.
Improve on the circuit 3 in the power factor shown in this figure, form the full-wave rectifying circuit that comprises a bridge rectifier Di and a smmothing capacitor Ci.To the additional circuit arrangement that comprises quick recovery type rectifier diode D1 and D2 and loosely coupled transformer VFT, is used to improve power factor of this full-wave rectifying circuit.
In this case, select the rectifier diode of recovery type at a slow speed respectively as the rectifier diode Da to Dd that constitutes bridge rectifier Di.In this case, the electrode input end of bridge rectifier Di (Da-Db tie point) is connected at tie point anodal circuit one side of electric main AC, between common mode choke CMC and the filtering capacitor CN.
The series connection of the secondary winding N12-rectifier diode D1 (anode-cathode) of loosely coupled transformer VFT by being used to improve power factor, the electrode input end of bridge rectifier Di is also connected to the positive terminal (the anodal circuit of rectification and smooth voltage Ei) of smmothing capacitor Ci.Can think that this series connection of secondary winding N12-rectifier diode D1 of loosely coupled transformer VFT is in parallel with the rectifier diode Da of bridge rectifier Di.
The cathode output end of bridge rectifier Di (Da-Dc tie point) is connected to the positive terminal of smmothing capacitor Ci.
The negative input of bridge rectifier Di (Dc-Dd tie point) is connected to tie point negative pole circuit one side, between common mode choke CMC and the filtering capacitor CN of electric main AC.The cathode output end of bridge rectifier Di is connected to primary side ground.
The secondary winding N12 of loosely coupled transformer VFT links to each other with the negative electrode of rectifier diode D2 with tie point between the anode of rectifier diode D1.The anode of rectifier diode D2 is connected to primary side ground.
Improve on the circuit 3 in the power factor that forms as mentioned above, rectified current in the positive polarity period of AC-input voltage VAC branches into: the first rectified current I1 component, flow through the rectified current path of negative pole circuit of anodal circuit → rectifier diode Da → smmothing capacitor Ci → rectifier diode Dd → electric main AC of electric main AC; And the second rectified current I2 component, flow through the rectified current path of negative pole circuit → filtering capacitor CN of secondary winding N12 → rectifier diode D1 → smmothing capacitor Ci → rectifier diode Dd → electric main AC of anodal circuit → loosely coupled transformer VFT of electric main AC.
In this case, flow through the rectifier diode Da and the Dd that carry out rectification on the rectified current path of first rectified current thereon and recover type at a slow speed, and do not carry out switching manipulation with its switch periods.Therefore, first rectified current does not form the alternation waveform.
On the contrary, on the path that flows through second rectified current, according to the alternating voltage of the secondary winding N12 of loosely coupled transformer VFT induction, rectifier diode D1 switching and rectifying electric current.Therefore, second rectified current forms the alternation waveform, therefore, flows into smmothing capacitor Ci.
In the negative polarity period of AC-input voltage VAC, rectified current branches into: first rectified current, flow through the rectified current path of anodal circuit of negative pole circuit → rectifier diode Dc → smmothing capacitor Ci → rectifier diode Db → electric main AC of electric main AC; And second rectified current, flow through the path of negative pole circuit → filtering capacitor CN of secondary winding N12 → electric main AC of negative pole circuit → rectifier diode Dc → smmothing capacitor Ci → rectifier diode D2 → loosely coupled transformer VFT of electric main AC.
In this case, in the period rectifier diode Dc and Db that first rectified current carries out rectification are recovered type at a slow speed in the negative polarity of AC-input voltage VAC, and do not carry out switching manipulation.Therefore, first rectified current does not form the alternation waveform.
On the contrary, fast quick-recovery type rectifier diode D2 switch second rectified current, it carries out switching manipulation according to the alternating voltage of the secondary winding N12 induction of loosely coupled transformer VFT.Therefore, second rectified current forms the alternation waveform.
Therefore, improve each positive polarity period/negative polarity period of AC-input voltage VAC on the circuit 3 in the power factor of power circuit shown in Figure 12, according to the switch output of the feedback voltage of loosely coupled transformer VFT feedback, the switching and rectifying electric current, thus form the alternation waveform.Therefore, as mentioned above, the angle of flow that exchanges input current IAC increases, thereby improves power factor.
In this case, the loosely coupled transformer VFT that is provided with on the power circuit according to the 5th embodiment shown in Figure 12 is as long as adopt structure shown in Figure 2 just enough.Yet for power circuit shown in Figure 12, the gap length that forms at the center of the E-E of loosely coupled transformer VFT shape iron core magnetic post is set to about 1mm, and the coupling coefficient between elementary winding N11 and the secondary winding N12 is set to about 0.8.In above-mentioned first to fourth embodiment, for example, coupling coefficient is set to 0.75 or lower respectively, and gap length is set to about 1.5mm respectively.
The coupling coefficient that changes loosely coupled transformer VFT in the present embodiment like this is relevant with the coupling coefficient that isolated variable transformer PIT is provided with.To do explanation to this point below.
Figure 14 illustrates with identical in above-mentioned each embodiment, when couple state being set with about coupling coefficient of 0.7 to 0.8, the equivalent circuit diagram of power circuit shown in Figure 12, this coupling coefficient are the elementary winding N1 of isolated variable transformer PIT and the coupling coefficient between the secondary winding N2 side.
For circuit shown in Figure 12, the inductance (LN11) of the elementary winding N11 of loosely coupled transformer VFT can be expressed as the magnetizing inductance Le11 of elementary winding N11 and being connected in series of leakage inductance Lk11.
In addition, the inductance (LN1) of the elementary winding N1 of isolated variable transformer PIT can also be expressed as the magnetizing inductance Le1 of elementary winding N1 and being connected in series of leakage inductance Lk1.
As can be seen from Figure 12, on the primary side series resonant circuit, the elementary winding N1 of isolated variable transformer PIT connects mutually with the elementary winding N11 of loosely coupled transformer VFT.
Therefore, according to equivalent electric circuit shown in Figure 14, will the inductance meter when primary side is seen isolated variable transformer PIT be shown being connected in series of leakage inductance Lk11 of the leakage inductance Lk11 of the magnetizing inductance Le11 of elementary winding N11, elementary winding N11 and elementary winding N1.Therefore, as shown in figure 15, the equivalent leakage inductance when primary side is seen isolated variable transformer PIT is expressed as:
Lk11+Lk1
This means, because the elementary winding N11 of loosely coupled transformer VFT connect with the elementary winding N1 of isolated variable transformer PIT, so in fact only in the primary side appearance of isolated variable transformer PIT the big leakage inductance of leakage inductance than isolated variable transformer PIT generation.
Therefore, knownly power circuit is being regarded as one when whole, the coupling coefficient between primary side and the primary side is 0.8 or lower.
The coupling coefficient of power circuit be 0.8 or lower state under, for example, when bearing power along with the increase of load during marked change, DC input voitage increases, and therefore, produces big change in voltage characteristic.
Therefore, in order to ensure from the AC-input voltage rated voltage ± 20% constant voltage control range to disconnecting consumers, for example, need to select to have the withstand voltage product of corresponding height as the smmothing capacitor (Ci) that is used to produce rectification and smooth voltage Ei (AC-input voltage), switching device (Q1 and Q2), primary side series resonance capacitor C1 etc.For example, cause the size of circuit board and weight to increase like this, this increase causes the size of subelement to increase simultaneously and cost raises.
In addition, when DC input voitage raise along with the increase of load, switching loss also increased, because along with the increase of load, also increased as the resistance of the switching device of MOS-FET.Therefore, reduced the AC/DC power conversion efficiency.
In addition, increase the excursion that means DC input voitage along with the increase of load big for DC input voitage.Therefore, expanded the switching frequency control range that is used to realize constant voltage, and dwindled control range.Meanwhile, the primary side rectifier output voltage that is controlled as constant voltage reduces according to the transient response characteristic between maximum load and the underload.
Therefore, the configuration present embodiment only makes isolated variable transformer PIT have 0.90 or higher coupling coefficient.
For example, as shown in figure 13, the structure of isolated variable transformer has E-E shape iron core, and this E-E shape iron core is to combine by E shape CR11 unshakable in one's determination and the CR12 that makes Ferrite Material, makes the magnetic post of CR11 unshakable in one's determination form facing to the magnetic post of CR12 unshakable in one's determination.
Isolated variable transformer PIT also has bobbin B, and this bobbin B for example utilizes resin to form, and this bobbin B has such shape, makes primary side winding part partly separate with the primary side winding, thus independence mutually.Elementary winding N1 is wrapped on the winding part of bobbin B.Secondary winding N2 is wrapped on another winding part of bobbin B.Therefore, the bobbin B that has twined elementary winding and secondary winding is installed on the E-E shape iron core (CR11 and CR12).Therefore, on variant winding zone, primary side winding and primary side winding are wrapped on the center magnetic post of E-E shape iron core.Therefore, obtained the overall structure of loosely coupled transformer VFT.
In this case, the gap length of the clearance G that forms by the bonding part that is arranged on center magnetic post obtains 0.90 or higher coupling coefficient.For coupling coefficient is set to 0.90 or higher, for example, it is just enough that gap length (situation that comprises gap length=0mm) only suitably is set at about 0.5mm or more among a small circle.
Figure 15 is illustrated in like this coupling coefficient of isolated variable transformer PIT and is set to 0.90 or when higher, the equivalent circuit diagram of circuit shown in Figure 12.
As shown in the drawing, the part series circuit of the elementary winding N11 of the elementary winding N1 of isolated variable transformer PIT and loosely coupled transformer VFT can be regarded as the leakage inductance component (Lk11+Lk1) of between the magnetizing inductance Le11 of the elementary winding N11 of the magnetizing inductance Le1 of the elementary winding N1 of isolated variable transformer PIT and loosely coupled transformer VFT, having connected.
Suppose and utilize equivalent electric circuit shown in Figure 15 to represent power circuit shown in Figure 12, the coupling coefficient that obtains on isolated variable transformer PIT is 0.93, and this isolated variable transformer has:
The EER-40 iron core
Gap length=0.4mm
Elementary winding N1=22T
Secondary winding N2:14T+14T, its centre cap is as the dividing potential drop position
Therefore, obtain following inductance value.
The inductance L N1=391 μ H of the elementary winding N1 of isolated variable transformer PIT
The leakage inductance LK1=49 μ F of the elementary winding N1 of isolated variable transformer PIT
The inductance L N2=111 μ H of the secondary winding N2 of isolated variable transformer PIT
The leakage inductance LK2=17 μ H of the elementary winding N1 of isolated variable transformer PIT
As mentioned above, the coupling coefficient of loosely coupled transformer VFT is about 0.8.Be set to 1mm and coupling coefficient is at 0.79 o'clock in the actual EE-28 of the having ferrite core of loosely coupled transformer VFT, gap length, the inductance value below obtaining.
The inductance L N11=70 μ H of the elementary winding N11 of loosely coupled transformer VFT
The inductance L N12=17 μ H of the secondary winding N12 of loosely coupled transformer VFT
Therefore, the coupling coefficient with whole power circuit of configuration shown in Figure 12 is 0.84, utilizes equivalent electric circuit shown in Figure 15 to represent this power circuit.Therefore, obtained the coupling coefficient higher than 0.80.
Figure 16 illustrates the experimental result as its coupling coefficient as mentioned above is 0.84, Figure 15 illustrates the power circuit shown in Figure 12 of its equivalent electric circuit, when AC-input voltage VAC=230V, for the variation of bearing power Po=0 to 250W, the variation of AC/DC power conversion efficiency (η AC/DC), power factor PF and rectification and smooth voltage Ei.Carry one in passing,, select the primary side series resonance capacitor C1 of 0.039 μ F in order to obtain the experimental result shown in this figure.
According to Figure 16, for the variation of bearing power Po=0 to 250W, the level of rectification and smooth voltage Ei is 336V to 327V, and therefore, it changes in the scope of 9V.Fully reduced this excursion.That is, the phenomenon that rectification and smooth voltage Ei (DC input voitage) enlarge markedly along with the increase of load does not appear, because make the coupling coefficient of entire circuit keep value or higher (for example, 0.8 or higher) that requires.
The AC/DC power conversion efficiency trends towards along with load improves from bearing power Po=0W to heavy duty variation.Although load variations scope difference, but for example compare explanation with the characteristic Fig. 4 that illustrates according to the power circuit of above-mentioned first embodiment, curve in load variations scope when load is light (for example, bearing power P0 is about 100W or the scope when lower among Figure 16) is milder.That is, suppressed the reduction of power conversion efficiency under light-load conditions.
About power factor, in the scope of bearing power Po=100W to 250W, keep PF＞0.75, therefore, satisfied supply harmonic distortion adjustment.
Because shown in the experimental result as shown in Figure 16, the level excursion of rectification and smooth voltage Ei reduces, so, for example, not need in order to ensure from the rated voltage of AC-input voltage ± 20% constant voltage control range to disconnecting consumers, and it is high withstand voltage that smmothing capacitor Ci on the power circuit shown in Figure 12, switching device (Q1 and Q2), primary side series resonance capacitor C1 etc. are had.Can reduce the size and the weight of circuit board like this, and can reduce cost.
In addition, as shown in figure 16, suppressed power conversion efficiency and under light-load conditions, reduced.In addition, owing to reduced the excursion of DC input voitage under light-load conditions, so constant voltage control level scope narrows down with respect to the switching frequency control range.That is, expanded the switching frequency control range relatively, thus the expansion adjusting range, and therefore improve adjusting range.In addition, as the spinoff of this situation, maximum load in the primary side VD stabilization process and the transient response characteristic between the underload are improved.
In addition, as mentioned above, elementary winding N1=22T explanation is set in the actual disposition of isolated variable transformer PIT, for example, with coupling coefficient wherein be 0.8 or lower situation compare, reduced the number of turn, because improved coupling coefficient by reducing gap length.
For example, be set to 0.8 or when lower, need the number of turn of elementary winding N1 to be about 33T at coupling coefficient.
Owing to reduced the number of turn like this, so reduced the wire rod cost of the winding of an isolated variable transformer PIT.As wire rod, for example, can select the litz wire of 60-μ φ/150 dishes (bundle).In addition, owing to reduced the number of turn,, improved production efficiency like this so shortened the winding processing time.
The following describes the modification of making according to the power circuit of the 5th embodiment shown in Figure 12.
As first example, the same with first embodiment shown in Figure 6, as shown in figure 12 on the primary side of circuit be shown in dotted line like that, have the parallel resonance capacitor C2 in parallel according to the power circuit of the 5th embodiment with the secondary winding N2 of isolated variable transformer PIT.
In addition, in this case, the electric capacity of parallel resonance capacitor C2 and the leakage inductance L2 of secondary winding N2 form the secondary lateral parallel resonant circuit.Capacitance according to the parallel resonance capacitor C2 of actual selection, the secondary lateral parallel resonant circuit is formed for the operational transformation of the primary side rectification circuit voltage resonant circuit for the operation of voltage resonance formula perhaps is formed for obtaining the part voltage resonant circuit of part voltage resonance operation.
As second modification example, replace configuration shown in Figure 12, circuit arrangement shown in Figure 1 is improved circuit 3 as power factor.In this case,, as mentioned above, the coupling coefficient of isolated variable transformer PIT and loosely coupled transformer VFT is set, thereby obtains power circuit according to the 5th embodiment although this circuit arrangement is identical with circuit arrangement shown in Figure 1.
In the 5th embodiment, no matter adopt which example, isolated variable transformer and power factor all are set improve the coupling coefficient of transformer, with the coupling coefficient that obtains entire circuit is required, and particularly isolated variable transformer have within it be provided with, do not represent the coupling coefficient of the requirement of loose coupling, thereby reduce the excursion of DC input voitage (rectification and smooth voltage) according to load variations.So just do not need to select high pressure-resistive products, therefore, can correspondingly reduce cost, and reduce the size and the weight of circuit board as the smmothing capacitor that is used to produce DC input voitage, switching device etc.So also suppress the power conversion efficiency reduction, perhaps improved power conversion efficiency easily, and further expanded the constant voltage control range.
Then, with the power circuit of explanation according to the 6th embodiment.According to the power circuit of the 6th embodiment based on configuration according to the power circuit of above-mentioned the 5th embodiment.
Yet, although the power circuit according to the 5th embodiment satisfies single scope electric main AC=200V standard and bearing power Po=250W or higher condition, satisfy single scope electric main AC=100V standard and bearing power Po=250W or higher condition according to the power circuit of the 6th embodiment.
In order to handle the input of electric main AC=100V standard, change the configuration that improves circuit 3 according to the power factor that comprises the rectification circuit system on the power circuit of the 6th embodiment.
Figure 17 illustrates the configuration example according to the power circuit of the 6th embodiment.Carry one in passing, in the figure, utilize same Ref. No. to represent and illustrate according to identical part in the accompanying drawing (Fig. 1, Fig. 6, Fig. 7, Figure 11 and Figure 12) of the power circuit of first to the 5th embodiment configuration, therefore omit explanation they.
In order to handle the electric main AC of 100V standard, the power factor of the power circuit shown in this figure is improved circuit 3 and is provided with voltage doubling rectifing circuit.
Bridge rectifier Di comprises rectifier diode Da of recovery type at a slow speed and Db.The anode of rectifier diode Da is connected at tie point negative pole circuit one side of electric main AC, between common mode choke CMC and the filtering capacitor CN, and its negative electrode is connected to the positive terminal (the anodal circuit of rectification and smooth voltage Ei) of smmothing capacitor Ci1.
The anode flow primary side ground of rectifier diode Db, and its negative electrode is connected to the anode of rectifier diode Da.
As smmothing capacitor, two smmothing capacitor Ci1-Ci2 of series connection mutually are set.The positive terminal of smmothing capacitor Ci1 is connected to the negative electrode of rectifier diode Da, as mentioned above.The negative pole end of smmothing capacitor Ci2 is connected to primary side ground.Tie point between the positive terminal of the negative pole end of smmothing capacitor Ci1 and smmothing capacitor Ci2 is connected at tie point negative pole circuit one side of electric main AC, between common mode choke CMC and the filtering capacitor CN.
On power factor was improved circuit 3, the series circuit of the secondary winding N12 of loosely coupled transformer VFT and the rectifier diode of recovery type at a slow speed D1 was connected the positive terminal (the anodal circuit of rectification and smooth voltage Ei) of smmothing capacitor Ci1 and between tie point anodal circuit one side of electric main AC, between common mode choke CMC and the filtering capacitor CN.In this case, the anode of rectifier diode D1 is connected to secondary winding N12, and its negative electrode is connected to the positive terminal of smmothing capacitor Ci1.
Tie point between the secondary winding N12 of the anode of rectifier diode D1 and loosely coupled transformer VFT links to each other with the negative electrode of fast quick-recovery type rectifier diode D2.The anode of rectifier diode D2 is connected to primary side ground.
As the rectified current during the negative polarity period of the AC-input voltage VAC on the power factor improvement circuit 3 of such formation, the first rectified current I1 flows through the path of the negative pole circuit of rectifier diode Da → smmothing capacitor Ci1 → electric main AC from the anodal circuit of electric main AC.In addition, the second rectified current I2 flows through the path of negative pole circuit → filtering capacitor CN of secondary winding N12 → rectifier diode D1 → smmothing capacitor Ci1 → electric main AC of loosely coupled transformer VFT from the anodal circuit of electric main AC.
In addition, in this case, first rectified current does not form the alternation waveform, because the rectifier diode of recovery type at a slow speed Da does not carry out switching manipulation.On the contrary, fast quick-recovery type rectifier diode D1 interrupts second rectified current, and according to the alternating voltage that the secondary winding N12 of loosely coupled transformer VFT obtains, this fast quick-recovery type rectifier diode D1 carries out switching manipulation.Therefore, second rectified current forms the alternation waveform, and flows into smmothing capacitor Ci1.
In the negative polarity period of AC-input voltage VAC, rectified current branches into: first rectified current, flow through the path of the anodal circuit of smmothing capacitor Ci2 → rectifier diode Db → electric main AC from the negative pole circuit of electric main AC; And second rectified current, flow through the path of anodal circuit → filtering capacitor CN of secondary winding N12 → electric main AC of smmothing capacitor Ci2 → rectifier diode D2 → loosely coupled transformer VFT from the negative pole circuit of electric main AC.
In addition, in this case, first rectified current does not form the alternation waveform, because the rectifier diode of recovery type at a slow speed Db does not carry out switching manipulation.On the contrary, rectifier diode D2 interrupts second rectified current, and according to the alternating voltage that secondary winding N12 that it is applied, loosely coupled transformer VFT obtains, this rectifier diode D2 carries out switching manipulation.Therefore, second rectified current forms the alternation waveform, and flows into smmothing capacitor Ci2.
Therefore, still in this case, in each positive polarity of AC-input voltage VAC period/negative polarity period, form rectified current and be branched the parallel passage portion that flows thereby rectified current flows through the path of rectifier diode of requirement of bridge rectifier Di and path that rectified current flows through fast quick-recovery type rectifier diode D1 or D2.
The rectified current that rectifier diode D1 or D2 switch flow on the path that is positioned at quick recovery type rectifier diode D1 or D2 one side.Therefore, as mentioned above, increased the angle of flow of interchange input current IAC, thereby improved power factor.
According to above-mentioned rectified current path, as the rectification operation, in the positive polarity period of AC-input voltage VAC, smmothing capacitor Ci1 charging, and in the negative polarity period of AC-input voltage VAC, smmothing capacitor Ci2 charging.Therefore, still in this case, realize the voltage multiplying rectifier operation, as the voltage at the series circuit two ends of smmothing capacitor Ci1-Ci2, the twice that rectification that this voltage multiplying rectifier operation produces and smooth voltage Ei are equivalent to the level of AC-input voltage VAC.
When Figure 20 was illustrated in and with about coupling coefficient of 0.7 to 0.8 couple state is set, the equivalent circuit diagram of power circuit shown in Figure 17, this coupling coefficient were the elementary winding N1 of isolated variable transformer PIT and the coupling coefficient between the secondary winding N2 side.
In addition, for circuit shown in Figure 20, the inductance (LN11) of the elementary winding N11 of loosely coupled transformer VFT can be expressed as the magnetizing inductance Le11 of elementary winding N11 and being connected in series of leakage inductance Lk11.
In addition, the inductance (LN1) of the elementary winding N1 of isolated variable transformer PIT can also be expressed as the magnetizing inductance Le1 of elementary winding N1 and being connected in series of leakage inductance Lk1.
In addition, in this case, as shown in figure 17, on the primary side series resonant circuit, the elementary winding N1 of isolated variable transformer PIT connects mutually with the elementary winding N11 of loosely coupled transformer VFT.
Therefore, shown in the equivalent electric circuit as shown in Figure 21, the leakage inductance of elementary winding N1 that will be when isolated variable transformer PIT side is watched is expressed as being connected in series of leakage inductance Lk1 of the leakage inductance Lk11 of elementary winding N11 and elementary winding N1.That is, as shown in figure 15, in this case, the actual leakage inductance of the elementary winding N1 of isolated variable transformer VFT is expressed as:
Lk11+Lk1
Therefore, power circuit is being regarded as one when whole, the coupling coefficient between primary side and the primary side is 0.8 or lower.
Therefore, configuration makes that according to the power circuit of the 6th embodiment the coupling coefficient of isolated variable transformer PIT only is 0.90 or higher.For example, Figure 13 illustrates the isolated variable transformer PIT that is used for this purpose, therefore, omits they are described.
Figure 21 is illustrated in like this coupling coefficient of isolated variable transformer PIT and is set to 0.90 or when higher, the equivalent circuit diagram of power circuit shown in Figure 17.
As shown in the drawing, the part series circuit of the elementary winding N11 of the elementary winding N1 of isolated variable transformer PIT and loosely coupled transformer VFT can be regarded as the leakage inductance component (Lk11+Lk1) of between the magnetizing inductance Le11 of the elementary winding N11 of the magnetizing inductance Le1 of the elementary winding N1 of isolated variable transformer PIT and loosely coupled transformer VFT, having connected.
Suppose and utilize equivalent electric circuit shown in Figure 21 to represent power circuit shown in Figure 17, the coupling coefficient that obtains on actual isolated variable transformer PIT is 0.93, and for example, this isolated variable transformer has:
The EER-40 iron core
Gap length=0.4mm
Elementary winding N1=22T
Secondary winding N2:14T+14T, its centre cap is as the dividing potential drop position
Therefore, obtain following inductance value.
The inductance L N1=319 μ H of the elementary winding N1 of isolated variable transformer PIT
The leakage inductance LK1=49 μ H of the elementary winding N1 of isolated variable transformer PIT
The inductance L N2=111 μ H of the secondary winding N2 of isolated variable transformer PIT
The leakage inductance LK2=17 μ F of the secondary winding N2 of isolated variable transformer PIT
Be set to approximately at 0.8 o'clock at coupling coefficient with loosely coupled transformer VFT, the actual gap length of loosely coupled transformer VFT with EE-28 ferrite core and 1.5mm, therefore and have 0.79 coupling coefficient.Therefore, obtain following inductance value.
The inductance L N11=95 μ H of the elementary winding N11 of loosely coupled transformer VFT
The inductance L N12=43 μ H of the secondary winding N12 of loosely coupled transformer VFT
Therefore, the coupling coefficient with whole power circuit of configuration shown in Figure 17 is 0.84, utilizes equivalent electric circuit shown in Figure 21 to represent this circuit.Therefore, obtained the coupling coefficient higher than 0.80.
Figure 22 illustrates the experimental result as its coupling coefficient as mentioned above is 0.84, Figure 21 illustrates the power circuit shown in Figure 17 of its equivalent electric circuit, when AC-input voltage VAC=100V, for the variation of bearing power Po=0 to 250W, the variation of AC/DC power conversion efficiency (η AC/DC), power factor PF and rectification and smooth voltage Ei.Carry one in passing,, select the primary side series resonance capacitor C1 of 0.022 μ F in order to obtain the experimental result shown in this figure.
According to Figure 22, still in this case, for the variation of bearing power Po=0 to 250W, the level of rectification and smooth voltage Ei is 270V to 312V, and therefore, it changes in the scope of 42V.This experimental result explanation having voltage doubling rectifing circuit, being used to handle electric main AC=100V and bearing power Po=250W or higher complex resonance converter, has fully reduced the excursion of DC input voitage level.
The explanation of the characteristic curve of AC/DC power conversion efficiency shown in this figure, the curve in the load variations scope when load is light is mild, therefore, has suppressed the reduction of power conversion efficiency under light-load conditions.
About power factor, in the scope of bearing power Po=15W to 250W, keep PF＞0.75, therefore, satisfied supply harmonic distortion adjustment.
From this characteristic curve as can be seen, do not need to have according to the smmothing capacitor Ci on the power circuit of the 6th embodiment, switching device (Q1 and Q2), primary side series resonance capacitor C1 etc. high withstand voltage.Can reduce the size and the weight of circuit board like this, and can reduce cost.
In addition, also having suppressed power conversion efficiency reduces under light-load conditions.In addition, because having suppressed DC input voitage raises under light-load conditions, so expanded by carrying out the constant voltage control range that switching frequency control realizes, therefore, maximum load in the primary side VD stable control process and the transient response characteristic between the underload are improved.
Modification as according to the power circuit of the 6th embodiment the following describes two examples.
Figure 18 illustrates the configuration as the modification of first example.
In this configuration as first example, parallel resonance capacitor C2 is in parallel with the secondary winding N2 of isolated variable transformer PIT, thereby form the secondary lateral parallel resonant circuit, as the voltage resonant circuit that is used for the operational transformation of primary side rectification circuit is operated for the voltage resonance formula, perhaps as the part voltage resonant circuit that is used to obtain the operation of part voltage resonance.
Improve on the circuit 3 in power factor, omitted the rectification circuit Di that utilization recovery type at a slow speed rectifier diode Da shown in Figure 17 and Db constitute.In the sort circuit configuration, utilize fast quick-recovery type rectifier diode D1, all rectified current components during the positive period of switch AC input voltage VAC, to form the alternation waveform, and utilize fast quick-recovery type rectifier diode D2, all rectified current components during the negative period of switch AC input voltage VAC are to form the alternation waveform.
Figure 19 illustrates the configuration as the modification of second example.
Although with identical in Figure 18, power factor shown in this figure is improved circuit 3 and is had two fast quick-recovery type rectifier diode D1 and D2 and two smmothing capacitor Ci1 and Ci2, but these two fast quick-recovery type rectifier diode D1 are different with the connected mode of two smmothing capacitor Ci1 of D2 and this and Ci2.
In this case, the negative pole end of smmothing capacitor Ci2 is connected to tie point on anodal circuit one side that is positioned at electric main AC, common mode choke CMC and filtering capacitor CN.By the secondary winding N12 of loosely coupled transformer VFT, the positive terminal of smmothing capacitor Ci2 is connected to the tie point between the negative electrode of the anode of rectifier diode D1 and rectifier diode D2, and this secondary winding N12 connects with the positive terminal of smmothing capacitor Ci2.
The negative electrode of rectifier diode D1 is connected to the positive terminal of smmothing capacitor Ci1.The anode of rectifier diode D2 is connected at tie point on negative pole circuit one side of electric main, between common mode choke CMC and the filtering capacitor CN.
In this case, be connected to primary side ground at tie point on negative pole circuit one side of electric main AC, between common mode choke CMC and the filtering capacitor CN, thereby be in earth potential.The negative pole end of smmothing capacitor Ci2 is connected to primary side ground.
The series circuit that is positioned at switching device Q1 on the following stages and Q2 is in parallel with smmothing capacitor Ci1.That is, in this case, utilize the voltage at smmothing capacitor Ci1 two ends, obtain DC input voitage (rectification and smooth voltage Ei).
The following describes power factor and improve the operation of circuit 3 with this configuration.
At first, in the negative polarity period of AC-input voltage VAC, rectified current flows through the path of negative pole circuit of secondary winding N12 → smmothing capacitor Ci2 → electric main ACD of rectifier diode D2 → loosely coupled transformer VFT from the negative pole circuit of electric main AC.
By making rectified current flow through above-mentioned rectified current path, smmothing capacitor Ci2 is recharged, and is equivalent to the current potential that AC-input voltage VAC multiply by 1 level thereby obtain its level at smmothing capacitor Ci2 two ends.
At this moment, the alternating voltage of responding on the secondary winding of loosely coupled transformer VFT is applied to rectifier diode D2.Therefore, rectifier diode D2 switch and interrupt this rectified current, therefore, this rectified current forms the alternation waveform with switch periods.Carry one in passing, the high fdrequency component of switch periods is absorbed, thereby flows through the filtering capacitor CN of above-mentioned rectified current path.
In the next negative polarity period of AC-input voltage VAC, rectified current flows through the path of the negative pole circuit (primary side ground) of secondary winding N12 → rectifier diode D1 → smmothing capacitor Ci1 → electric main AC of smmothing capacitor Ci2 → loosely coupled transformer VFT from the anodal circuit of electric main AC.
By making rectified current flow through above-mentioned rectified current path, smmothing capacitor Ci1 is recharged, and makes the current potential that obtains at the two ends of smmothing capacitor Ci2 be superimposed upon on the level of AC-input voltage VAC.Therefore, obtain rectification and the smooth voltage Ei that its level is equivalent to the twice of AC-input voltage VAC at the two ends of smmothing capacitor Ci1.That is, realize the voltage multiplying rectifier operation.
In above-mentioned rectified current path, the alternating voltage of responding on the secondary winding N12 of loosely coupled transformer VFT is applied to rectifier diode D1.Therefore, this rectified current of rectifier diode D1 switch.
Therefore, still in this case, according at each positive polarity of AC-input voltage VAC period/negative polarity period, the switch output of the feedback voltage feedback of loosely coupled transformer VFT, switching and rectifying electric current.That is, realize power factor improvement operation.
Carry one in passing, for example, adopt Figure 17 or power factor shown in Figure 19 to improve to be provided with on the power circuit of configuration of circuit 3 shown in Figure 180 according to the 6th embodiment as the secondary lateral parallel resonant circuit of revising.That is, can add the secondary lateral parallel resonant circuit, and not be subjected to power factor to improve the restriction of the configuration of circuit 3.
Then, with the power circuit of explanation according to the 7th embodiment.Power circuit according to the 7th embodiment is so-called wide region power circuit, and it can handle electric main AC=100V standard and AC=200V standard.Be that according to the power circuit of the 7th embodiment and something in common power circuit is handled bearing power Po=250W or higher according to the power circuit of the 5th and the 6th embodiment.
Figure 23 illustrates the configuration example according to the power circuit of the 7th embodiment.Carry one in passing, in the figure, utilize same Ref. No. to represent and illustrate according to the identical part of part in the accompanying drawing of the configuration of the power circuit of first to the 5th embodiment, therefore, omit explanation they.
Improve on the circuit 3 in the power factor shown in this figure, improving the identical connected mode of connected mode in the circuit 3, a filtering capacitor CN, the bridge rectifier Di that comprises the rectifier diode of recovery type at a slow speed Da to Dd and two fast quick-recovery type rectifier diode D1 and D2 are linked together with the power factor of the power circuit according to the 5th embodiment shown in Figure 12.
In this case, two smmothing capacitor Ci1 and Ci2 are set, as the smmothing capacitor that is used to produce rectification and smooth voltage Ei (DC input voitage).As shown in the drawing, smmothing capacitor Ci1 and Ci2 connect mutually.The positive terminal of smmothing capacitor Ci1 is connected to the cathode output end of bridge rectifier Di of rectification and smooth voltage Ei and the tie point between the fast quick-recovery type rectifier diode.The negative pole end of smmothing capacitor Ci2 is connected to primary side ground.
By switch S, mutually the tie point between the positive terminal of the negative pole end of the smmothing capacitor Ci1 of series connection and smmothing capacitor Ci2 is connected at tie point negative pole circuit one side of electric main AC, between common mode choke CMC and the filtering capacitor CN.
Switch S is carried out switch, so that for answering the input of AC 100V standard to equal, be switched on during less than the AC-input voltage VAC of 150V, and is being disconnected when answering the input of AC 200V standard to equal 150V or higher AC-input voltage VAC.Although the not shown circuit part that is used for the switch control of switch S among Figure 23,, for example, relay switch is used as switch S.Therefore, be provided with one and be arranged to the level that detects AC-input voltage VAC and just enough by the circuit part that drives electromagnetic relay switch switch S according to testing result.
The power factor that the following describes the rectification circuit system with such configuration is improved the operation of circuit 3.
At first, when the input of corresponding electric main AC=100V standard is lower than the AC-input voltage VAC of 150V, and when therefore connecting switch S, following formation voltage doubling rectifing circuit.
When AC-input voltage VAC is in positive polarity, first rectified current flows on the path of the negative pole circuit of anodal circuit → rectifier diode Da → smmothing capacitor Ci1 → switch S → electric main AC of electric main AC, and second rectified current flows on the path of negative pole circuit → filtering capacitor CN of secondary winding N12 → rectifier diode D1 → smmothing capacitor Ci1 → switch S → electric main AC of anodal circuit → loosely coupled transformer VFT of electric main AC.
This first rectified current and second rectified current charge to smmothing capacitor Ci1.Therefore, utilize the voltage at smmothing capacitor Ci1 two ends, obtain its level and be equivalent to AC-input voltage VAC and multiply by 1 direct voltage.
Flow thereon on the rectified current path of second rectified current, according to the alternating voltage of on the secondary winding N12 of loosely coupled transformer VFT, responding to, fast quick-recovery type rectifier diode D1 switch second rectified current.That is, second rectified current forms the alternation waveform.
When AC-input voltage VAC is in negative polarity, first rectified current flows on the path of the anodal circuit of negative pole circuit → switch S → smmothing capacitor Ci2 → rectifier diode Db → electric main AC of electric main AC, and second rectified current flows into the path of anodal circuit → filtering capacitor CN of secondary winding N12 → electric main AC of smmothing capacitor Ci2 → rectifier diode D2 → loosely coupled transformer VFT by switch S from the negative pole circuit of electric main AC.
This first rectified current and second rectified current charge to smmothing capacitor Ci2.Therefore, utilize the voltage at smmothing capacitor Ci2 two ends, obtain its level and be equivalent to AC-input voltage VAC and multiply by 1 direct voltage.
Therefore, utilize the voltage at the series circuit two ends of smmothing capacitor Ci1-Ci2, obtain the direct voltage that its level is equivalent to the twice of AC-input voltage VAC.That is, realize the voltage multiplying rectifier operation.
In addition, in the negative polarity period of AC-input voltage VAC, flow thereon on the rectified current path of second rectified current, according to the alternating voltage of on the secondary winding N12 of loosely coupled transformer VFT, responding to, fast quick-recovery type rectifier diode D2 switch second rectified current.Therefore, second rectified current forms the alternation waveform.
Therefore, respectively in positive period/negative period of AC-input voltage VAC, fast quick-recovery type rectifier diode D1 or D2 switch second rectified current, thus flow with the alternation waveform.As mentioned above, because the rectified current component forms the alternation waveform like this, increase so exchange the angle of flow of input current IAC, thereby improve power factor.
When corresponding electric main AC=200V standard input 150V or higher AC-input voltage VAC, switch S disconnects.The circuit arrangement that switch S is in power factor improvement circuit 3 when disconnecting is identical with the circuit arrangement according to the improvement of the power factor on the power circuit of the 5th embodiment circuit shown in Figure 12.Specifically, in this case, utilize of the series circuit charging of the electric current of full-wave rectification operation rectification to smmothing capacitor Ci1-Ci2.Utilize the voltage at smmothing capacitor Ci1-Ci2 series circuit two ends, obtain its level and be equivalent to AC-input voltage VAC and multiply by 1 rectification and smooth voltage Ei (direct voltage).
In addition, in this case, Figure 12 is described as reference, realizes respectively the positive period/negative period at AC-input voltage VAC, utilizes the operation of fast quick-recovery type rectifier diode D1 or D2 switch second rectified current.
Figure 20 illustrates when as the elementary winding N1 of isolated variable transformer PIT and the coupling coefficient between the secondary winding couple state being set with about coupling coefficient of 0.7 to 0.8, and the equivalent electric circuit of the power circuit according to the 7th embodiment shown in Figure 23 is done explanation below.Therefore, in this case, the actual leakage inductance of the elementary winding N1 of isolated variable transformer PIT also is represented as:
Lk11+LKk1
Therefore, power circuit is being regarded as one when whole, the coupling coefficient between primary side and the primary side is 0.8 or lower.
Therefore, also like this configuration is according to the power circuit of the 7th embodiment, makes isolated variable transformer PIT only obtain 0.90 or higher coupling coefficient, and is for example, described with reference to Figure 13.
The coupling coefficient that Figure 21 is illustrated in isolated variable transformer PIT is set to 0.90 or when higher, the equivalent electric circuit of power circuit shown in Figure 23.
Therefore, still on power circuit shown in Figure 23, the part series circuit of the elementary winding N11 of the elementary winding N1 of isolated variable transformer PIT and loosely coupled transformer VFT can be regarded as the leakage inductance component (Lk11+Lk1) of between the magnetizing inductance Le11 of the elementary winding N11 of the magnetizing inductance Le1 of the elementary winding N1 of isolated variable transformer PIT and loosely coupled transformer VFT, having connected.
Suppose and utilize equivalent electric circuit shown in Figure 21 to represent power circuit shown in Figure 23, with the identical mode of above-mentioned the 6th embodiment, form according to the actual isolated variable transformer on the power circuit of the 7th embodiment, thereby obtain 0.93 coupling coefficient.Therefore, for the inductance L N1 of the elementary winding N1 of isolated variable transformer PIT and inductance L N2 and the leakage inductance LK2 of leakage inductance LK1 and secondary winding N2, obtain the value identical with the value of in the 6th embodiment, describing.
In fact, also dispose loosely coupled transformer VFT in the mode identical with mode among the 6th embodiment, therefore, it has 0.75 coupling coefficient.In addition, for the inductance L N1 of the elementary winding N11 of loosely coupled transformer VFT and the inductance L N12 of secondary winding N12, obtain the value identical with the value of in the 6th embodiment, describing.
Therefore, the coupling coefficient with whole power circuit of configuration shown in Figure 23 is 0.84, utilizes equivalent electric circuit shown in Figure 21 to represent this circuit.Therefore, obtained the coupling coefficient higher than 0.80.
Figure 25 and Figure 26 illustrate the experimental result as its coupling coefficient is 0.84, Figure 21 illustrates the power circuit shown in Figure 17 of its equivalent electric circuit, for the variation of bearing power Po=0 to 250W, the variation of AC/DC power conversion efficiency (η AC/DC), power factor PF and rectification and smooth voltage Ei.The characteristic curve of (when being AC 100V standard) when Figure 25 is illustrated in AC-input voltage VAC=100V.The characteristic curve of (when being AC 200V standard) when Figure 26 is illustrated in AC-input voltage VAC=230V.In order to obtain the experimental result shown in this figure, select the primary side series resonance capacitor C1 of 0.022 μ F.
According to Figure 25 and Figure 26, for the variation of bearing power Po=0 to 250W, the level of rectification and smooth voltage Ei changes in the scope at 46V when AC-input voltage VAC=100V, and changes in the scope at 19V when AC-input voltage VAC=230V.This experimental result also illustrates, when AC 100V standard and AC 200V standard, being used to handle bearing power Po=250W or higher complex resonance converter, has fully reduced the excursion of DC input voitage level.
AC/DC power conversion efficiency characteristic curve shown in these two figure illustrates that also the curve in the load variations scope when load is light is mild, therefore, has suppressed the reduction of power conversion efficiency under light-load conditions, perhaps improves power conversion efficiency.
About power factor, when AC-input voltage VAC=100V, in the scope of bearing power Po=15W to 250W, keep PF＞0.80, and when AC-input voltage VAC=230V, in the scope of bearing power Po=100W to 250W, keep PF＞0.75.Therefore, under two kinds of initial conditions of AC-input voltage VAC, satisfied supply harmonic distortion adjustment.
Owing to obtained this characteristic curve, so have same effect according to power circuit and the above-mentioned the 5th and the 6th embodiment of the 7th embodiment.
Figure 24 illustrates the modification according to the power circuit of the 7th embodiment.Carry one in passing, in the figure, utilize same Ref. No. to represent and the identical each several part of part among Figure 23, therefore omit explanation they.
Power factor at circuit shown in this figure is improved on the circuit 3, has omitted fast quick-recovery type rectifier diode D1 and D2 shown in Figure 23.On the contrary, in this case, select fast quick-recovery type rectifier diode as the rectifier diode Da to Dd that constitutes bridge rectifier Di.
In this case, the tie point between the smmothing capacitor Ci1-Ci2 is connected to the terminal t2 of relay switch S1.
Relay switch S1 is so-called on-off switch.The such switch of relay switch S1 makes and utilizes the electromagnetic relay RL that the following describes, and makes terminal t1 alternately be connected to terminal t2 or t3.
In this case, the end of the secondary winding N12 of loosely coupled transformer VFT is connected to the anodal circuit of rectification and smooth voltage Ei (DC input voitage).The other end of the secondary winding N12 of loosely coupled transformer VFT is connected to the anodal circuit of electric main AC and the electrode input end of bridge rectifier Di.
In this case, form the elementary winding N11 of loosely coupled transformer VFT,, it is divided into winding part N11A and N11B so that utilize tap.By series resonance capacitor C1, the end of winding part N11A is connected to the switch output point.Tie point between winding part N11A and the N11B is connected to the terminal t2 of relay switch S2.The end of winding part N11B is connected to the terminal t3 of relay switch S2.
Relay switch S2 also is an on-off switch.The switch relay switch S 2 like this, make to utilize electromagnetic relay RL, make terminal t1 alternately be connected to terminal t2 or t3.
In the figure, rectification circuit switch module 5 is set, as the circuit part that is used to drive relay R L.In this case, will comprise that the direct voltage of the half-wave rectifying circuit acquisition of diode D10 and capacitor C10 is input to the terminal T14 of rectification circuit switch module 5 as detection voltage.Because to half-wave rectifying circuit (D10 and C10) supply electric main AC, and its execution rectification operation, so rectification circuit switch module 5 detects the level of AC-input voltage VAC.
Electromagnetic relay is connected between the terminal T12 and T13 of rectification circuit switch module 5.By the electric current that flows between terminal T12 and T13 is carried out on, rectification circuit switch module 5 drives electromagnetic relay RL, thereby makes relay switch S1 and S2 switch.
When the detection level of AC-input voltage VAC is lower than 150V (when AC 100V standard), rectification circuit switch module 5 drives electromagnetic relay RL, makes the terminal t1-t2 of relay switch S1 and S2 be connected to each other and is in the same place.
At first, on relay switch S1, terminal t1-t2 is connected to each other together, improves on the circuit 3 forming voltage doubling rectifing circuit in power factor.
Specifically, in the positive polarity period of AC-input voltage VAC, rectified current flows through the path of negative pole circuit (filtering capacitor CN) of anodal circuit → rectifier diode Da → smmothing capacitor Ci1 → (relay switch S1) → electric main AC of electric main AC.At this moment, electric current also flows through the path of negative pole circuit (filtering capacitor CN) of secondary winding N12 → smmothing capacitor Ci1 → (relay switch S1) → electric main AC of anodal circuit → loosely coupled transformer VFT of electric main AC.
Therefore, rectified current utilizes the voltage at smmothing capacitor Ci1 two ends to smmothing capacitor Ci1 charging, has obtained its level and has equaled the direct voltage that AC-input voltage multiply by 1 level.
As mentioned above, owing to inserted the secondary winding N12 of loosely coupled transformer VFT, thus the alternating voltage of the switch periods that on the rectified current path, superposeed, and fast quick-recovery type rectifier diode Da switch first rectified current, thereby form the alternation waveform.
In the negative pole period of AC-input voltage VAC, rectified current flows through the path of anodal circuit (filtering capacitor CN) of negative pole circuit → (relay switch S1) → smmothing capacitor Ci2 → rectifier diode Dc → electric main AC of electric main AC.
At this moment, rectified current is to smmothing capacitor Ci2 charging, thereby utilizes the voltage at smmothing capacitor Ci2 two ends, obtains its level and equals the direct voltage that AC-input voltage VAC multiply by 1 level.Therefore, utilize the voltage at the smmothing capacitor Ci1-Ci2 two ends of series connection mutually, obtain rectification and smooth voltage Ei, this rectification and smooth voltage E are the direct voltages that its level is equivalent to the twice of AC-input voltage VAC.That is, realize the voltage multiplying rectifier operation.
The secondary winding N12 of loosely coupled transformer VFT is connected to the cathode terminal of rectifier diode Dc.Therefore, utilize fast quick-recovery type rectifier diode Dc switch to flow through the rectified current of above-mentioned path, thereby form the alternation waveform.
When the terminal t1-t2 of relay switch S2 side was connected to each other together, only winding part N11A effectively was used as the elementary winding N11 of loosely coupled transformer VFT.
Then, be 150V or when higher (in AC 200V standard time), rectification circuit switch module 5 drives electromagnetic relay RL at the detection level of AC-input voltage VAC, make the terminal t1-t3 of relay switch S1 and S2 be connected to each other and be in the same place.
When on relay switch S1, when terminal t1-t2 was connected to each other together, terminal t2 disconnected, and therefore, the tie point between the smmothing capacitor Ci1-Ci2 is free of attachment to the negative pole circuit of electric main AC.Therefore, full-wave rectifying circuit forms rectified current.
Specifically, in the positive polarity period of AC-input voltage VAC, rectified current flow through the anodal circuit of electric main AC → → path of the negative pole circuit (filtering capacitor CN) of smmothing capacitor Ci1-Ci2 → rectifier diode Dd → electric main AC.At this moment, charging current branch, the secondary winding N12 that passes through loosely coupled transformer VFT with the anodal circuit from electric main AC flows into smmothing capacitor Ci1-Ci2.
In the negative pole period of AC-input voltage VAC, rectified current flows through the path of anodal circuit (filtering capacitor CN) of negative pole circuit → rectifier diode Db → smmothing capacitor Ci1-Ci2 → rectifier diode Dc → electric main AC of electric main AC.
Therefore, respectively in anodal period/negative pole period of AC-input voltage VAC, rectified current is to the smmothing capacitor Ci1-Ci2 charging of mutual series connection, thereby utilize the voltage at smmothing capacitor Ci1-Ci2 two ends, obtain its level and be equivalent to AC-input voltage VAC and multiply by 1 rectification and smooth voltage Ei (DC input voitage).That is, realize the full-wave rectification operation.
When the terminal t1-t3 on relay switch S2 was connected to each other together, winding part N11A and N11B effectively were used as the elementary winding N11 of loosely coupled transformer VFT.
From the top description of doing as can be seen, identical with power circuit shown in Figure 23, switch was used to produce the configuration of the rectification circuit system of rectification and smooth voltage Ei between full-wave rectification when adopting voltage multiplying rectifier operation when the AC 100V standard with AC 200V standard was operated, and power circuit shown in Figure 24 can be a wide region.
In the time of AC 100V standard and AC 200V standard, respectively in positive period/negative period of AC-input voltage VAC, constitute rectifier diode Da to the Dd switching and rectifying electric current of bridge rectifier Di, therefore, realized that also power factor improves operation.
In addition, change the elementary winding N11 of the loosely coupled transformer VFT on the circuit shown in Figure 24, make when AC-input voltage VAC is lower than 150V (during AC 100V standard), only winding part N11A is effective, and be 150V or when higher (in AC 200V standard time), the series connection of winding part N11A-N11B is effective at AC-input voltage VAC.That is, change like this, make and compare when the AC 100V standard, the number of turn of the elementary winding N11 of loosely coupled transformer VFT is big when AC 200V standard.
When the number of turn of the elementary winding N11 of loosely coupled transformer VFT is changed, the turn ratio of elementary winding N11 and secondary winding N12 also changes, and secondary winding N12 level upward induction and that be fed back to the alternating voltage of rectified current path also changes.
Therefore, for example, be about at bearing power P0 under the condition of 250W, when AC 100V standard, the power factor of present embodiment is about 0.75, therefore, has improved power conversion efficiency.
Known and identical on power circuit according to the foregoing description, for example, feeding back to the rectified current path by the feedback voltage that utilizes loosely coupled transformer VFT that switch is exported, thereby improve in the configuration of power factor, the ripple voltage of high fdrequency component is superimposed upon on DC input voitage (rectification and the smooth voltage) Ei.
Therefore, on circuit shown in Figure 24, although the end of elementary winding N1 is connected to the switch output point by primary side series resonance capacitor C1 from the elementary winding N11 of loosely coupled transformer VFT, the other end of elementary winding N1 is connected to the positive terminal of smmothing capacitor Ci1.That is, an end of primary side series resonant circuit is connected to the anodal circuit of rectification and smooth voltage Ei, and is free of attachment to primary side ground.
In this case, for example, the rectified current that can flow through the secondary winding N12 that flows through loosely coupled transformer VFT of the primary side resonance current of elementary winding N11 of loosely coupled transformer VFT and alternation waveform is set to anti-phase mutually.
Therefore, be connected to the positive terminal of smmothing capacitor Ci1 at the end of elementary winding N1, and primary side resonance current and power factor to improve the electric current that flows on the circuit 3 mutual when anti-phase, utilize power factor to improve the phase-veversal switch output component of the Voltage Feedback feedback on the circuit 3, eliminate high fdrequency component as the primary side resonance current of switch output.
Therefore, the ripple voltage component that has suppressed rectification and smooth voltage Ei.
Carry one in passing, as mentioned above, for example, utilize the winding direction of the winding (N11 and N12) of loosely coupled transformer VFT respectively, can the primary side resonance current and power factor improve the electric current that flows on the circuit 3 and be set to anti-phase mutually.
In addition, for example, utilize the relation between the winding direction of winding (N1 and N2) of the winding direction of winding (N11 and N12) of loosely coupled transformer VFT and isolated variable transformer PIT, realize this setting.
In addition, on power circuit shown in Figure 24, parallel resonance capacitor C2 is in parallel with the secondary winding N2 of isolated variable transformer PIT, thereby form the secondary lateral parallel resonant circuit, as the voltage resonant circuit that is used for the operational transformation of primary side rectification circuit is operated for the voltage resonance formula, perhaps as the part voltage resonant circuit that is used to obtain the operation of part voltage resonance.
Carry one in passing, still in this embodiment, for example, can be to the additional secondary lateral parallel resonant circuit of circuit arrangement shown in Figure 23.
The present invention is not limited to above-mentioned power circuit configuration.
As switching device, for example,, can use non-MOS-FET device such as IGBT (insulated gate bipolar transistor) as long as this device can be used for outside excitation system.In addition, can be according to actual conditions etc., change the constant of each part mentioned above and element etc.
In addition, utilize the auto-excitation type current resonance converter that adopts the semibridge system coupled system, can form according to power circuit of the present invention.In this case, for example, can select bipolar transistor as switching device.
In addition, in the time of suitably, can Change Example as being used for producing the circuit arrangement of primary side VD in the primary side of isolated variable transformer PIT.
In addition, the circuit arrangement that power factor is improved circuit 3 is not limited to the configuration of the foregoing description explanation, and can select available configuration from each circuit arrangement of the various Voltage Feedback system that adopts that the inventor so far advises.

Claims (9)

1, a kind of switching power circuit comprises:
Rectification and smoothing apparatus are used to produce rectification and smooth voltage, and described rectification and smoothing apparatus comprise the rectifying device that is used for the rectification AC-input voltage and be used for the smmothing capacitor of the voltage of level and smooth rectifying device rectification;
Switching device is provided rectification and smooth voltage that described rectification and smoothing apparatus produce, and is used to carry out switching manipulation, utilizes two switching devices by semibridge system coupling coupling to constitute described switching device;
Driving mechanism for switch is used for described two switching devices of switch drive, so that described two switching devices replace on/off;
Isolated variable transformer, form this isolated variable transformer by twining elementary winding and secondary winding, described elementary winding is provided the switch output of the switching manipulation acquisition of described switching device, when obtaining switch output, elementary winding responds to alternating voltage on the described secondary winding, and this isolated variable transformer forms the gap of predetermined length, with the loose coupling state of the coupling coefficient that obtains to have requirement;
The primary side series resonant circuit, be provided the switch output of described switching device, and be the operation of current resonance formula with the operational transformation of described switching device, utilize the leakage inductance component of described elementary winding at least and form described primary side series resonant circuit with the electric capacity of the primary side series resonance capacitor of described elementary windings in series;
The VD generating apparatus is configured to by being received in the alternating voltage that described secondary winding obtains and carrying out the rectification operation, produces the primary side VD;
The constant voltage control device is configured to by the level according to described primary side VD, controls the switching frequency that described driving mechanism for switch changes described switching device, and described primary side VD is carried out constant voltage control; And
Power factor is improved transformer, power factor is improved elementary winding and power factor is improved secondary winding by twining, form this power factor and improve transformer, described power factor is improved the insertion of connecting with described primary side series resonant circuit of elementary winding, and described power factor is improved secondary winding and inserted the rectification that forms described rectification and smoothing apparatus and level and smooth path;
Wherein improve elementary winding according to described power factor and improve the alternating voltage of responding on the secondary winding in described power factor, the rectifying device of described rectification and smoothing apparatus is carried out switching manipulation.
2, switching power circuit according to claim 1, wherein,
Described rectification and smoothing apparatus are voltage multiplying rectifier and smoothing apparatus,
Comprise two smmothing capacitors, promptly, be used for the positive period in described AC-input voltage, smoothly by utilizing the smmothing capacitor of the voltage that the described AC-input voltage of rectifying device rectification obtains, and be used for negative period in described AC-input voltage, smoothly by utilizing the smmothing capacitor of the voltage that the described AC-input voltage of rectifying device rectification obtains; And
Form like this, the feasible voltage that obtains by the voltage at described two the smmothing capacitor two ends of adding up is described rectification and smooth voltage.
3, a kind of switching power circuit comprises:
Rectification and smoothing apparatus comprise: a plurality of low frequency rectifying devices are used for respectively the positive period/negative period in AC-input voltage, the rectification AC-input voltage; And smmothing capacitor, be used for the voltage of level and smooth low frequency rectifying device rectification;
Switching device is provided rectification and smooth voltage that described rectification and smoothing apparatus produce, and is used to carry out switching manipulation, utilizes two switching devices by semibridge system coupling coupling to constitute described switching device;
Driving mechanism for switch is used for described two switching devices of switch drive, so that described two switching devices replace on/off;
Isolated variable transformer, form this isolated variable transformer by twining elementary winding and secondary winding, described elementary winding is provided the switch output of the switching manipulation acquisition of described switching device, when obtaining switch output, elementary winding responds to alternating voltage on the described secondary winding, and this isolated variable transformer forms the gap of predetermined length, with the loose coupling state of the coupling coefficient that obtains to have requirement;
The primary side series resonant circuit, be provided the switch output of described switching device, and be the operation of current resonance formula with the operational transformation of described switching device, utilize the leakage inductance component of described elementary winding at least and form described primary side series resonant circuit with the electric capacity of the primary side series resonance capacitor of described elementary windings in series;
The VD generating apparatus is configured to by being received in the alternating voltage that described secondary winding obtains and carrying out the rectification operation, produces the primary side VD;
The constant voltage control device is configured to by the level according to described primary side VD, controls the switching frequency that described driving mechanism for switch changes described switching device, and described primary side VD is carried out constant voltage control;
Power factor is improved transformer, power factor is improved elementary winding and power factor is improved secondary winding by twining, form this power factor and improve transformer, described power factor is improved the insertion of connecting with described primary side series resonant circuit of elementary winding, and described power factor is improved secondary winding and is connected in parallel with the predetermined rectified current path that forms described rectification and smoothing apparatus; And
A plurality of high-frequency rectification devices, improving secondary winding with described power factor connects, be used to utilize described power factor to improve elementary winding, improve the positive period/negative period of the alternating voltage of secondary winding induction respectively in power factor, carry out switching manipulation, compare with the frequency of described AC-input voltage, described alternating voltage has high frequency.
4, switching power circuit according to claim 3, wherein,
Described rectification and smoothing apparatus are voltage multiplying rectifier and smoothing apparatus,
Comprise two smmothing capacitors, promptly, be used for the positive period in described AC-input voltage, smoothly by utilizing the smmothing capacitor of the voltage that the described AC-input voltage of rectifying device rectification obtains, and be used for negative period in described AC-input voltage, smoothly by utilizing the smmothing capacitor of the voltage that the described AC-input voltage of rectifying device rectification obtains; And
Form like this, the feasible voltage that obtains by the voltage at described two the smmothing capacitor two ends of adding up is described rectification and smooth voltage.
5, a kind of switching power circuit comprises:
Rectification and smoothing apparatus comprise: a plurality of rectifying devices are used for respectively the positive period/negative period in AC-input voltage, the rectification AC-input voltage; And smmothing capacitor, be used for the voltage of level and smooth rectifying device rectification;
Switching device is provided rectification and smooth voltage that described rectification and smoothing apparatus produce, and is used to carry out switching manipulation, utilizes two switching devices by semibridge system coupling coupling to constitute described switching device;
Driving mechanism for switch is used for described two switching devices of switch drive, so that described two switching devices replace on/off;
Isolated variable transformer, form this isolated variable transformer by twining elementary winding and secondary winding, described elementary winding is provided the switch output of the switching manipulation acquisition of described switching device, when obtaining switch output, elementary winding responds to alternating voltage on the described secondary winding, and this isolated variable transformer forms the gap of predetermined length, with the loose coupling state of the coupling coefficient that obtains to have requirement;
The primary side series resonant circuit, be provided the switch output of described switching device, and be the operation of current resonance formula with the operational transformation of described switching device, utilize the leakage inductance component of described elementary winding at least and form described primary side series resonant circuit with the electric capacity of the primary side series resonance capacitor of described elementary windings in series;
The VD generating apparatus is configured to by being received in the alternating voltage that described secondary winding obtains and carrying out the rectification operation, produces the primary side VD;
The constant voltage control device is configured to by the level according to described primary side VD, controls the switching frequency that described driving mechanism for switch changes described switching device, and described primary side VD is carried out constant voltage control; And
Power factor is improved transformer, power factor is improved elementary winding and power factor is improved secondary winding by twining, form this power factor and improve transformer, described power factor is improved the insertion of connecting with described primary side series resonant circuit of elementary winding, and described power factor is improved secondary winding and is connected in parallel with the predetermined rectified current path that forms described rectification and smoothing apparatus;
Wherein improve elementary winding according to described power factor and improve the alternating voltage of responding on the secondary winding in described power factor, the rectifying device of described rectification and smoothing apparatus is carried out switching manipulation.
6, according to claim 1, one of 3 and 5 described switching power circuits, wherein,
Improve between elementary winding and the described power factor improvement secondary winding in described power factor, obtain the loose coupling state of the coupling coefficient of requirement; And
In order to obtain the coupling coefficient of required value or higher value at described isolated variable transformer, with corresponding with the coupling coefficient of the requirement that obtains as the coupling coefficient of whole described power circuit, the gap of described isolated variable transformer is set to the length in the predetermined range.
7, according to claim 1, one of 3 and 5 described switching power circuits, further comprise the primary side part voltage resonant circuit that forms with the leakage inductance component of the electric capacity of described two switching devices part voltage resonance capacitor one of at least in parallel and described elementary winding by comprising at least, only according to the time that makes each described switching device switch, described primary side part voltage resonant circuit is carried out the voltage resonance operation.
8, switching power circuit according to claim 5, wherein,
Described rectification comprises rectifying device and two circuit that the smmothing capacitor of connecting mutually constitutes that utilize bridge-type to connect by four with smoothing apparatus, the feasible rectified current that utilizes full-wave rectification to obtain, described four rectifying devices that utilize described bridge-type to connect charge to described two smmothing capacitors of connecting; And
Described switching power circuit further comprises:
Switching device is inserted into ON/OFF between described two smmothing capacitors and alternating current transmission line, and
Switch controlling device is used to control, and is fiducial value or when higher with the level at described alternating current, disconnects described switching device, and when the level of described alternating current is lower than fiducial value, connects described switching device.
9, switching power circuit according to claim 5, wherein,
Utilize tap, described power factor is improved elementary winding be divided into two parts, the end that described power factor is improved a partitioning portion of elementary winding is connected to described primary side series resonance capacitor; And
Described switching power circuit further comprises:
Switching device is used to carry out switch, improves the end of another partitioning portion of elementary winding and the terminal of described tap to select described power factor, as the part of the end of the elementary winding that will be connected to isolated variable transformer, and
Switch controlling device, be used for carrying out control, with the level at described alternating current is fiducial value or when higher, make described switching device select described power factor to improve the end of another partitioning portion of elementary winding, and when the level of described alternating current is lower than fiducial value, make described switching device select the terminal of described tap.
CN 200380104394 2002-11-29 2003-11-28 Switching power supply circuit Pending CN1717857A (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP348139/2002 2002-11-29
JP2002348139 2002-11-29
JP008689/2003 2003-01-16
JP359754/2003 2003-10-20

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CN1717857A true CN1717857A (en) 2006-01-04

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101079575B (en) * 2006-05-24 2012-08-29 英特赛尔美国股份有限公司 DC-DC converters having improved current sensing and related methods
CN107924783A (en) * 2015-09-02 2018-04-17 西门子公司 DC switch equipment

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101079575B (en) * 2006-05-24 2012-08-29 英特赛尔美国股份有限公司 DC-DC converters having improved current sensing and related methods
CN107924783A (en) * 2015-09-02 2018-04-17 西门子公司 DC switch equipment
US10490365B2 (en) 2015-09-02 2019-11-26 Siemens Aktiengesellschaft Direct-current switching device

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