CN202406029U - Holding time prolongation circuit for resonant converter - Google Patents

Abstract

The utility model provides a holding time prolongation circuit for a resonant converter. The circuit comprises the components as following: coils (La2, La3, La4, La5), which are coupled to the magnetizing inductor at the primary side of the transformer in the resonant converter; impedance elements (Lb2, Rb3, Rb4, Lb5), which are connected to the coils (La2, La3, La4, La5); and switch circuits (211, 311, 411, 511), which are connected between the impedance elements (Lb2, Rb3, Rb4, Lb5) and the coils (La2, La3, La4, La5). When the input voltage of the resonant converter is reduced to a predetermined threshold, the switch circuits (211, 311, 411, 511) are conducted, the output voltage of the resonant converter is induced to the coils (La2, La3, La4, La5) through the magnetizing inductor (Lm), an induced current is generated in the coils, and the flow direction of the induced current is consistent with the flow direction of the current in the primary coil of the transformer when the resonant converter works normally.

Description

The retention time that is used for resonance converter prolongs circuit

Technical field

The disclosure relates to the circuit of the retention time that is used to prolong resonance converter.

Background technology

Increasingly high to the efficient requirement of Power Conversion in the market, for example, 80plus platinum standard-required is issued to the efficient greater than 94% in the half load situation.Resonance converter (Resonant converter) is owing to have efficient, high frequency and characteristics such as high power density and just obtaining increasingly extensive application.

Figure 1A shows a kind of schematic circuit of semibridge system resonance converter.Shown in Figure 1A, VDC representes power supply, 103 expression loads.This semibridge system resonance converter comprises two switch element Q1 and Q2 (among the figure these two elements being depicted as field-effect transistor), controller 101 and transformer T1.Switch element Q1 and Q2 are connected to the primary coil of transformer T1.In when work, controller 101 control these two switch element Q1 and Q2 alternate conduction are charged and are discharged with the primary coil to transformer T1.In addition, this semibridge system resonance converter also comprises resonant circuit 102.This resonant circuit 102 comprises resonant capacitance Cr, resonant inductance Lr and magnetizing inductance Lm.Here, the magnetizing inductance of the primary side of Lm indication transformer T1.In addition, this resonance converter also comprises the rectification circuit that diode D1, D2 and output capacitance Cout constitute, and is not described further here.

Figure 1B shows a kind of schematic circuit of full-bridge type resonance converter.Shown in Figure 1B, the circuit structure of this full-bridge type resonance converter is similar with the semibridge system resonance converter shown in Figure 1A, and difference is that this full-bridge type resonance converter comprises 4 switch element Q1, Q2, Q5 and Q6.These 4 switch element Q1, Q2, Q5 and Q6 are connected to the primary coil of transformer T1, and wherein, Q1 and Q6 partner and conducting simultaneously and shutoff, and Q2 and Q5 form another to and while conducting and shutoff.These two pairs of switch element alternate conduction of controller 101 control are charged and are discharged with the primary coil to transformer T1.

The utility model content

Inventor of the present disclosure finds; Between the conversion efficiency of resonance converter and retention time (retention time described here (hold up time) is meant the time quantum of the output voltage that keeps being provided to load when input voltage undesired (reducing suddenly like input voltage)) performance, need usually compromisely to consider; For example; Can be through increasing the switching loss that magnetizing inductance Lm improves conversion efficiency and reduces the switch element (field-effect transistor Q1 and Q2 shown in Figure 1A) in the resonance converter; But, on the other hand, increase magnetizing inductance Lm and also can cause the retention time of resonance converter to be reduced greatly.Embodiment of the present disclosure provides a kind of retention time that is used for resonance converter to prolong circuit, utilizes this circuit, can under the situation of the conversion efficiency that does not reduce resonance converter, prolong the retention time of resonance converter greatly.

Provide hereinafter about brief overview of the present disclosure, so that the basic comprehension about some aspect of the present disclosure is provided.Should be appreciated that this general introduction is not to exhaustive general introduction of the present disclosure.It is not that intention is confirmed key of the present disclosure or pith, neither be intended to limit the scope of the present disclosure.Its purpose only is to provide some notion with the form of simplifying, with this as the preorder in greater detail of argumentation after a while.

According to an aspect of the present disclosure, a kind of circuit that is used for resonance converter is provided, this circuit can comprise: coil, this coil is coupled to the magnetizing inductance of the primary side of the transformer in the said resonance converter; Impedance component, this impedance component is connected with said coil; And switching circuit; This switching circuit is connected between said impedance component and the said coil; Wherein, when the input voltage of resonance converter is reduced to predetermined threshold, said switching circuit conducting; Make the output voltage (primary side of transformer) of said resonance converter sense said coil and in said coil, produce induced current through said magnetizing inductance, the direction of current flow in the primary coil of this faradic flow direction transformer during with the resonance converter operate as normal is consistent.

Description of drawings

The disclosure can wherein use same or analogous Reference numeral to represent identical or similar parts in institute's drawings attached through with reference to hereinafter combining the given description of accompanying drawing to be better understood.Said accompanying drawing comprises in this manual and forms the part of this specification together with following detailed description, and is used for further illustrating preferred embodiment of the present disclosure and explains principle and advantage of the present disclosure.In the accompanying drawings:

Figure 1A shows the schematic circuit according to the semibridge system resonance converter of correlation technique;

Figure 1B shows the schematic circuit according to the full-bridge type resonance converter of correlation technique;

Fig. 2 A shows and has used the schematic circuit that prolongs the resonance converter of circuit according to retention time of the disclosure one embodiment;

Fig. 2 B shows the schematic circuit of another resonance converter of the retention time prolongation circuit of having used shown in Fig. 2 A;

Fig. 2 C shows the schematic circuit of another resonance converter of the retention time prolongation circuit of having used shown in Fig. 2 A;

Fig. 3 A shows the schematic circuit of having used according to the resonance converter of the circuit of another embodiment of the disclosure;

Fig. 3 B shows the schematic circuit of another resonance converter of the retention time prolongation circuit of having used shown in Fig. 3 A;

Fig. 3 C shows the schematic circuit of another resonance converter of the retention time prolongation circuit of having used shown in Fig. 3 A;

Fig. 4 A shows the schematic circuit of having used according to the resonance converter of the circuit of another embodiment of the disclosure;

Fig. 4 B shows the schematic circuit of another resonance converter of the retention time prolongation circuit of having used shown in Fig. 4 A;

Fig. 4 C shows the schematic circuit of another resonance converter of the retention time prolongation circuit of having used shown in Fig. 4 A;

Fig. 5 A shows the schematic circuit of having used according to the resonance converter of the circuit of another embodiment of the disclosure;

Fig. 5 B shows the schematic circuit of another resonance converter of the retention time prolongation circuit of having used shown in Fig. 5 A; And

Fig. 6 is the indicative flowchart that illustrates according to the method for retention time of the prolongation resonance converter of an embodiment of the present disclosure.

It will be appreciated by those skilled in the art that in the accompanying drawing each parts only for simple and clear for the purpose of and illustrate, rather than draw in proportion.For example, the size of some parts possibly or dwindled with respect to the miscellaneous part amplification in the accompanying drawing, and this is in order to help to improve the understanding to disclosure embodiment.

Embodiment

To combine accompanying drawing that example embodiment of the present disclosure is described hereinafter.In order to know and for simplicity, in specification, not describe all characteristics of actual execution mode.Yet; Should understand; In the process of any this practical embodiments of exploitation, must make a lot of decisions, so that realize developer's objectives, for example specific to execution mode; Meet and system and professional those relevant restrictive conditions, and these restrictive conditions may change along with the difference of execution mode to some extent.At this; What also need explain a bit is; For fear of having blured the disclosure because of unnecessary details, only show in the accompanying drawings with according to closely-related apparatus structure of scheme of the present disclosure and/or parts, and omitted other details little with disclosure relation.

Embodiment of the present disclosure provides circuit and the method for the retention time that can prolong resonance converter.

Inventor of the present disclosure finds that the retention time parameter of resonance converter depends on the voltage amplitude on the resonant capacitor.Keep the stage at output voltage, the voltage amplitude on the resonant capacitor is high more, and then the retention time is long more.Can reduce the voltage amplitude on the resonant capacitor through reducing magnetizing inductance Lm; Thereby prolong the retention time; But, reduce magnetizing inductance Lm and can increase switch element (MOSFET Q1 shown in Figure 1A and Q2 etc.) in the resonance converter in the switching loss of normal work period.Prolong the magnetizing inductance of primary side that circuit can be connected to the transformer of resonance converter according to retention time of embodiment of the present disclosure.When the input voltage of resonance converter undesired (as being reduced to a predetermined threshold); This circuit is started working; Flow through the magnetizing current of the resonant capacitor of resonance converter with increase, thereby increase the voltage amplitude on the resonant capacitor, prolong the retention time of resonance converter.Because prolong circuit only in when undesired (the be input voltage) work of maintenance stage according to retention time of embodiment of the present disclosure, therefore, it can not have influence on the conversion efficiency of resonance converter normal work period.

Fig. 2 A illustrates to have used the schematic circuit that prolongs the resonance converter of circuit according to retention time of the disclosure one embodiment.Shown in Fig. 2 A, prolong circuit 210 according to retention time of the disclosure one embodiment and can be applied in a kind of semibridge system resonance converter circuit.

This retention time prolongs circuit 210 and comprises ancillary coil La2, impedance component Lb2 and have switch element Q32 and the switching circuit 211 of switch element Q42.Coil La2 is coupled to the magnetizing inductance Lm (this magnetizing inductance Lm both can be arranged in this primary coil, also can be used as resolution element and was arranged at outside the primary coil, was not described further) of primary side of the transformer T1 of resonance converter here.Impedance component Lb2 be connected in coil La2 and comprise switch element Q32 and the switching circuit of switch element Q42 between.In this embodiment, impedance component Lb2 is shown as inductance element (as other embodiment, this inductance element can also replace with resistive element), and switch element Q32 in the switching circuit and Q42 all are shown as field-effect transistor (MOSFET).Particularly, the end of inductance component L b2 (first end that is called inductance component L b2) is connected to the end (first end that is called coil La2) of coil La2, and the other end (second end that is called inductance component L b2) is connected to switching circuit.In the embodiment shown in Fig. 2 A, second end of inductance component L b2 is connected to the drain electrode of switch element Q32.The source electrode of the source electrode of switch element Q32 and switch element Q34 is connected to each other and ground connection.The grid of switch element Q32 and Q34 is connected respectively to the controller 101 of resonance converter.Other parts of resonance converter shown in Fig. 2 A are similar with the circuit shown in Figure 1A, do not do repetition here.

101 couples of switch element Q32 of controller and Q34 control.When the resonance converter operate as normal, comprise that the switching circuit of switch element Q32 and Q34 turn-offs, promptly retention time prolongation circuit 210 is not worked.And (be reduced to a predetermined threshold like VDC when the input voltage of resonance converter is undesired; This predetermined threshold can be set according to practical application; Here do not limit) time, 101 couples of switch element Q32 of controller and Q34 control (for example, when input voltage is reduced to predetermined threshold; Controller can send the trigger voltage that makes switch element Q32 and Q34 conducting), make its conducting.In this case, the output voltage V o of resonance converter (primary side of transformer) meeting is sensed ancillary coil La2 side through the magnetizing inductance of the primary side of transformer, thereby on inductance component L b2, produces voltage Vb.The available following formula of relation between this voltage Vb and the output voltage V o is represented

$\mathrm{Vb}=\mathrm{Vo}\·n\·\frac{N2}{N1}---\left(1\right)$

In following formula, the primary coil of n indication transformer T1 and the turn ratio between the secondary coil, N2 representes the number of turn of coil La2, N1 representes the number of turn of magnetizing inductance Lm.

Like this, can produce the electric current that flows through impedance component Lb2, this electric current reflects through coil La2 gets back to magnetizing inductance Lm, makes the electric current that flows through magnetizing inductance Lm increase, and the corresponding feasible electric current that flows through the primary coil of transformer increases.Like this, flow through the corresponding increase of electric current meeting of resonant capacitance Cr, thus the energy storage that improves resonant capacitance Cr, the retention time of prolongation resonance converter.

At impedance component Lb2 is under the situation of inductance element, and the induced current Ib that flows through impedance component Lb2 that is produced can represent with following formula:

$\mathrm{Ib}=\frac{\mathrm{Vo}\·n\·{\left(\frac{N2}{N1}\right)}^3}{\mathrm{Lb}}\·t---\left(2\right)$

In following formula, Lb representes the inductance value of inductance component L b2, and t representes switch element Q1 or the ON time (being the inverse of the switching frequency in the resonance converter) of Q2 in the resonance converter.

As another example, be under the situation of resistive element at impedance component Lb2, the induced current Ib that flows through impedance component Lb2 that is produced can represent with following formula:

$\mathrm{Ib}=\frac{\mathrm{Vo}\·n\·{\left(\frac{N2}{N1}\right)}^2}{R}---\left(3\right)$

In following formula, R representes that impedance component Lb2 is the resistance value of this resistive element under the situation of resistive element.

Root mean square (RMS) the electric current I cs_RMS that flows through resonant capacitor Cr can calculate with following formula:

$\mathrm{Ics}\_\mathrm{RMS}=\sqrt{\frac{1}{8}}(\frac{{\mathrm{Io}}^2\·{\mathrm{\π}}^2}{n^2}+\frac{{\mathrm{Vin}}^2}{16\·{\mathrm{Lm}}^2\·{\mathrm{fsw}}^2})---\left(4\right)$

RMS voltage Vcs_RMS on the resonant capacitor Cr can calculate with following formula:

$\mathrm{Vcs}\_\mathrm{RMS}=\frac{\mathrm{Ics}\_\mathrm{RMS}}{2\mathrm{\π}\·\mathrm{Cr}\·\mathrm{fr}}---\left(5\right)$

In with following formula (4) and (5); Io representes the output current of resonance converter, and n representes primary coil and the turn ratio between the secondary coil of the transformer of resonance converter, and Vin representes the input voltage of resonance converter; The magnetizing inductance of the primary side of Lm indication transformer, fsw representes switching frequency.Cr representes the capacitance of resonant capacitor.Fr representes resonance frequency; And

wherein, Lr representes the inductance value of the resonant inductor of the resonant circuit in the resonance converter.

Can find out that from following formula flow through the RMS electric current of resonant capacitor Cr through increase, it is big that the voltage on the resonant capacitor Cr can become.

Through the above-mentioned retention time is prolonged circuit application to resonance converter; When input voltage is undesired; This retention time prolongs the switching circuit conducting in the circuit; Make the output voltage of resonance converter sense coil La2 and in coil La2, produce induced current through magnetizing inductance Lm, the direction of current flow in the primary coil of this faradic flow direction transformer during with the resonance converter operate as normal is consistent.The induced current that is produced is got back to the magnetizing inductance side from coil La2 reflection, makes the electric current that flows through the resonant capacitance Cr in the resonance converter increase, thereby improves the voltage on the resonant capacitance Cr.Like this, the output voltage of resonance converter can remain in certain level and not descend, thereby prolongs the retention time of resonance converter.In addition, because the above-mentioned retention time prolongs circuit in not conducting of resonance converter normal work period (promptly not working), therefore, it can not reduce the conversion efficiency of resonance converter, can not increase the switching loss in the switching device.

As a concrete applying examples, each element shown in Fig. 2 A can adopt following model and parameter:

Q1，Q2：IRFP460

Lr：20uH

Cr：66n

Lm：150uH

Lb2:20uH, wherein, N1=12, N2=2

Q3，Q4：IPP085N06

D1，D2：MBR6045WT

Cout：1500uF

Vo：12V

Load: 35A

n＝16

Should be understood that above-mentioned parameter and model only are concrete examples.In practical application, the element shown in each embodiment in the disclosure can come according to the actual requirements to confirm, and should not be limited to above-mentioned numerical value and model.

Fig. 2 B shows the retention time shown in Fig. 2 A is prolonged the schematic circuit that circuit 210 is applied to another kind of resonance converter.The difference of the resonance converter shown in the resonance converter shown in Fig. 2 B and Fig. 2 A is that it comprises two resonant capacitance Cr1 and Cr2.It is identical with the circuit 210 shown in Fig. 2 A that retention time shown in Fig. 2 B prolongs circuit 210, no longer is repeated in this description here.

Fig. 2 C shows the retention time shown in Fig. 2 A is prolonged the schematic circuit that circuit 210 is applied to the full-bridge type resonance converter.The difference of the resonance converter shown in the resonance converter shown in Fig. 2 C and Fig. 2 A is that it comprises 4 switch element Q1, Q2, Q5 and Q6, and these four switch elements constitute full-bridge circuit.It is identical with the circuit 210 shown in Fig. 2 A that retention time shown in Fig. 2 C prolongs circuit 210, also no longer is repeated in this description here.

Prolong in the circuit 210 in the retention time shown in Fig. 2 A-2C; Using switch element Q42 is in order only to allow electric current to flow in one direction; Direction of current flow when guaranteeing that faradic flow direction among the impedance component Lb2 is with the resonance converter operate as normal in the primary coil of transformer is consistent, and can be mobile along opposite direction.In some other embodiment, this switch element Q42 can also substitute with other switching circuits.Fig. 3 A-3C and Fig. 4 A-4C show the embodiment that utilizes other forms of switching circuit to come alternative switch element Q42 respectively.

Fig. 3 A illustrates to have used the schematic circuit that prolongs the resonance converter of circuit according to retention time of another embodiment of the disclosure.Shown in Fig. 3 A, prolong circuit 310 according to retention time of another embodiment of the disclosure and can be applied in a kind of semibridge system resonance converter circuit.

Retention time prolongs circuit 310 and comprises that (in this embodiment, this impedance component is shown as resistive element for ancillary coil La3, impedance component Rb3.As other embodiment, this resistive element can also replace with inductance element) and switching circuit 311.This switching circuit 311 comprises the diode full-bridge circuit that switch element Q33 and diode D3, D4, D5 and D6 constitute.Coil La3 is coupled to the magnetizing inductance Lm of primary side of the transformer T1 of resonance converter.The end of impedance component Rb3 is connected to coil La3 through the diode full-bridge, and the other end links to each other with the end of switch element Q33.The other end of switch element Q33 is connected to diode bridge circuit, and this diode bridge circuit is also connected to the two ends of coil La3.In addition, switch element Q33 also with said resonance converter in controller 101 link to each other.When unusual (as being reduced to predetermined threshold) appearred in the input voltage of said resonance converter, this controller made switch element Q33 conducting.In Fig. 3 A, Q33 is shown as MOSFET.The drain electrode of switch element Q33 is connected to the end of impedance component Rb3, and grid is connected to controller 101, and source ground.The anode of diode D3 is connected to the end of coil La3, and negative electrode is connected to the end of impedance component Rb3.The anode of diode D4 is connected to the other end of coil La3, and negative electrode is connected to the negative electrode of diode D3.The anode of diode D5 is connected to anode and the ground connection of diode D6, and negative electrode is connected to the anode of diode D3.The negative electrode of diode D6 is connected to the anode of diode D4.

Compare with the circuit 210 shown in Fig. 2 A, the retention time prolong circuit 310 with shown in the diode full-bridge circuit come alternative switch element Q42.Here; The diode full-bridge circuit that diode D3, D4, D5 and D6 constitute is identical with the function of switch element Q42; Only allow electric current to flow in one direction; Be that direction of current flow in the primary coil of transformer when guaranteeing that faradic flow direction among the impedance component Rb3 is with the resonance converter operate as normal is consistent, and can be along flowing in the other direction.In addition, this diode full-bridge circuit need not be connected to the controller 101 of resonance converter.101 couples of switch element Q33 of controller control.When the resonance converter operate as normal, switch element Q33 turn-offs, and promptly retention time prolongation circuit 310 is not worked.And when the input voltage of resonance converter undesired (when being reduced to a predetermined threshold) like VDC; 101 couples of switch element Q33 of controller (for example control; When input voltage is reduced to predetermined threshold; Controller can send the trigger voltage that makes switch element Q33 conducting), make its conducting, promptly the retention time prolongs circuit 310 work.Except switching circuit, the function that the retention time prolongs other elements La3 and Rb3 in the circuit 310 be connected with circuit 210 in La2 similar with Lb2, no longer repetition here.

Fig. 3 B shows the retention time shown in Fig. 3 A is prolonged the schematic circuit that circuit 310 is applied to another kind of resonance converter.The difference of the resonance converter shown in the resonance converter shown in Fig. 3 B and Fig. 3 A is that it comprises two resonant capacitance Cr1 and Cr2.It is identical with the circuit 310 shown in Fig. 3 A that retention time shown in Fig. 3 B prolongs circuit 310, no longer is repeated in this description here.

Fig. 3 C shows the retention time shown in Fig. 3 A is prolonged the schematic circuit that circuit 310 is applied to the full-bridge type resonance converter.The difference of the resonance converter shown in the resonance converter shown in Fig. 3 C and Fig. 3 A is that it comprises 4 switch element Q1, Q2, Q5 and Q6, and these four switch elements constitute full-bridge circuit.It is identical with the circuit 310 shown in Fig. 3 A that retention time shown in Fig. 3 C prolongs circuit 310, also no longer is repeated in this description here.

Fig. 4 A illustrates to have used the schematic circuit that prolongs the resonance converter of circuit according to retention time of another embodiment of the disclosure.Shown in Fig. 4 A, prolong circuit 410 according to retention time of this another embodiment of the disclosure and can be applied in a kind of semibridge system resonance converter circuit.

Retention time prolongs circuit 410 and comprises that (in this embodiment, this impedance component is shown as resistive element for ancillary coil La4, impedance component Rb4.As other embodiment, this resistive element can also replace with inductance element) and switching circuit 411.Switching circuit 411 comprises the diode half-bridge circuit that switch element Q34 and diode D34, D44 constitute.The end of switch element Q34 is connected to the end of impedance component Rb4, and the other end is connected to diode bridge circuit, and links to each other with controller 101 in the resonance converter at the other end.Diode bridge circuit is also connected to the two ends of the other end and the coil La4 of impedance component Rb4.Particularly, in Fig. 4 A, switch element Q34 is shown as MOSFET.The drain electrode of this MOSFET is connected to the end of impedance component Rb4, and grid is connected to controller 101, and source ground and link to each other with coil La4.The anode of diode D44 is connected to an end of coil, and negative electrode is connected to the impedor other end.The anode of diode D34 is connected to the other end of coil, and negative electrode is connected to the negative electrode of diode D44.

In addition, shown in Fig. 4 A, be provided with the tap of ground connection among the ancillary coil La4.The position of this tap is in the centre of coil La4.This tapped coil La4 can be used as full-wave rectifier (similar with the diode full-bridge circuit (D3, D4, D5 and D6) among Fig. 3 A-3C, as only to allow electric current to flow in one direction) with diode D34 and D44.In this tapped configuration, the amplitude of electric current is identical in two of alternating current different half periods.One skilled in the art should appreciate that this tapped configuration, be not described further here.(D3, D4, D5 and D6) compares with the diode full-bridge shown in Fig. 3 A-3C, and the switching circuit shown in Fig. 4 B-4C that Fig. 4 A and back are described has lacked two diodes, so structure is simpler.Compare with the circuit 210 shown in Fig. 2 A, the retention time prolong circuit 410 with shown in diode half-bridge circuit and tapped La4 come alternative switch element Q42.Here; Diode D3 is identical with the function of switch element Q42 with D34 and tapped La4; Be that direction of current flow in the primary coil of transformer when guaranteeing that faradic flow direction among the impedance component Rb4 is with the resonance converter operate as normal is consistent, and can be along flowing in the other direction.In addition, D34 and D44 need not be connected to the controller 101 of resonance converter.Controller 101 is only controlled switch element Q34.When the resonance converter operate as normal, switch element Q34 turn-offs, and promptly retention time prolongation circuit 410 is not worked.And when the input voltage of resonance converter undesired (when being reduced to a predetermined threshold) like VDC; 101 couples of switch element Q34 of controller (for example control; When input voltage is reduced to predetermined threshold; Controller can send the trigger voltage that makes switch element Q34 conducting), make its conducting, promptly the retention time prolongs circuit 410 work.Except switching circuit, the function that the retention time prolongs other elements La4 and Rb4 in the circuit 410 be connected with circuit 210 in La2 similar with Lb2, no longer repetition here.

Fig. 4 B shows the retention time shown in Fig. 4 A is prolonged the schematic circuit that circuit 410 is applied to another kind of resonance converter.The difference of the resonance converter shown in the resonance converter shown in Fig. 4 B and Fig. 4 A is that it comprises two resonant capacitance Cr1 and Cr2.It is identical with the circuit 410 shown in Fig. 4 A that retention time shown in Fig. 4 B prolongs circuit 410, no longer is repeated in this description here.

Fig. 4 C shows the retention time shown in Fig. 4 A is prolonged the schematic circuit that circuit 410 is applied to the full-bridge type resonance converter.The difference of the resonance converter shown in the resonance converter shown in Fig. 4 C and Fig. 4 A is that it comprises 4 switch element Q1, Q2, Q5 and Q6, and these four switch elements constitute full-bridge circuit.It is identical with the circuit 410 shown in Fig. 4 A that retention time shown in Fig. 4 C prolongs circuit 410, also no longer is repeated in this description here.

In the embodiment shown in Fig. 2 A-2C, 3A-3C and the 4A-4C; The switching circuit that retention time prolongs circuit 210,310 and 410 all needs the controller 101 in the resonance converter to control; So that these switching circuits were connected in input voltage unusual when being reduced to predetermined threshold (as) time; (it will be appreciated by those skilled in the art that and turn-off in other cases; When the retention time shown in Fig. 2 A-2C, 3A-3C and the 4A-4C is prolonged circuit application in resonance converter, can be configured wherein controller 101 with any appropriate method, so that this controller sends triggering signals (as sending trigger voltage to these switching circuits when input voltage unusual when being reduced to predetermined threshold (as); Here be not described further); Thereby make these switch connections, make then that in other cases these switches keep turn-offing, be not described further here).In some other embodiment; Retention time prolongs the switching circuit of circuit and can when input voltage unusual (being reduced to a predetermined threshold like input voltage), connect automatically; And keep in other cases turn-offing, need not control by the controller in the resonance converter 101.Fig. 5 A and 5B show such embodiment.

Fig. 5 A illustrates to have used the schematic circuit that prolongs the resonance converter of circuit according to retention time of another embodiment of the disclosure.Shown in Fig. 5 A, prolong circuit 510 according to retention time of this another embodiment of the disclosure and can be applied in a kind of full-bridge type resonance converter circuit.

Retention time prolongs circuit 510 and comprises that (in this embodiment, this impedance component is shown as inductance element for ancillary coil La5, impedance component Lb5.As other embodiment, this inductance element can also replace with resistive element) and switching circuit 511.Switching circuit 511 comprises the diode full-bridge circuit that diode D35, D45, D55 and D65 constitute.This diode full-bridge circuit is connected between the end of coil La5 and impedance component Lb5, and the other end of impedance component Lb5 is connected to the input power supply of resonance converter.Particularly, shown in Fig. 5 A, the anode of diode D35 is connected to the end of coil La5, and negative electrode is connected to the end of impedance component Lb5.The anode of diode D45 is connected to the other end of coil La5, and negative electrode is connected to the negative electrode of diode D35.The anode of diode D55 is connected to anode and the ground connection of diode D65, and negative electrode is connected to the anode of diode D35.The negative electrode of diode D65 is connected to the anode of diode D45.Compare with 410 with circuit shown in Fig. 2 A-2C, 3A-3C and the 4A-4C 210,310, the retention time prolongs circuit 510 and does not comprise switch element Q32, Q33 or Q34, and its switching circuit need not the control of the controller of resonance converter.When the resonance converter operate as normal, the retention time prolongs circuit 510 and does not work.And when the input voltage (like VDC) of resonance converter undesired (when being reduced to a predetermined threshold) like VDC, this change in voltage can be in impedance component Lb5 inducing current.This electric current can reflect through coil La5 gets back to magnetizing inductance Lm.That is, the diode full-bridge circuit conducting that D35, D45, D55 and D65 constitute, the retention time prolongs circuit 510 work.Except switching circuit, the function that the retention time prolongs other elements La5 and Lb5 in the circuit 510 be connected with circuit 210 in La2 similar with Lb2, no longer repetition here.Capacitor C 5 shown in Fig. 5 A is for being used for stored energy and the body capacitance (bulk capacitor) of reliable dc voltage being provided to resonance converter.This capacitor C 5 is selectable units.When not comprising this electric capacity in the resonance converter shown in Fig. 5 A, but its also operate as normal.

Fig. 5 B shows the retention time shown in Fig. 5 A is prolonged the schematic circuit that circuit 510 is applied to another kind of resonance converter.Be that with the difference of the resonance converter shown in Fig. 5 A the resonance converter shown in Fig. 5 B is the semibridge system resonance converter that comprises two resonant capacitance Cr1 and Cr2.It is identical with the circuit 510 shown in Fig. 5 A that retention time shown in Fig. 5 B prolongs circuit 510, no longer is repeated in this description here.

Retention time shown in Fig. 5 A and the 5B prolongs circuit 510 can start working when undesired at the input voltage of resonance converter (when being reduced to a predetermined threshold like VDC) automatically, and the controller that need not resonance converter is controlled.Compare with reference to the embodiment that figure 2A-2C, 3A-3C and 4A-4C describe with preceding text, the structure that the retention time prolongs circuit 510 is simpler.

In addition; In above accompanying drawing; The circuit symbol of field-effect transistor (like Q1, Q2, Q5, Q6, Q32, Q42 etc.) is shown as and comprises the diode that is connected in parallel between its drain electrode and the source electrode; This is the direction of current flow when these MOSFET conductings are shown, and does not represent extra diode is parallel to these switch elements.

According to embodiment more of the present disclosure a kind of method that prolongs the retention time of resonance converter is provided also.Fig. 6 shows the flow chart according to the method for the retention time of the prolongation resonance converter of an embodiment.

As shown in Figure 6, in step 601, whether the input voltage that detects resonance converter has taken place unusually.If unusual (being reduced to a predetermined threshold like input voltage) taken place; Then in step 603; Make the output voltage of institute's resonance converter respond to the primary side of getting back to transformer through the transformer of resonance converter; In the magnetizing inductance of primary side, to produce induced current, wherein, the direction of current flow in the time of should making this faradic flow direction with the resonance converter operate as normal in the primary coil of transformer is consistent.

As specific embodiment, can implement said method through above-mentioned retention time prolongation circuit 211,311,411 or 511 is connected to resonance converter.Particularly, can the coil that the retention time prolongs circuit be coupled to the magnetizing inductance of primary side of the transformer of resonance converter.When (being reduced to a predetermined threshold like input voltage) taken place unusually in the input voltage of resonance converter; Making the retention time prolong circuit 211,311,411 or 511 starts working; So that the output voltage of institute's resonance converter is responded to the primary side of getting back to transformer through the transformer of resonance converter; Producing induced voltage on the impedance component that prolongs circuit in the retention time, thereby in magnetizing inductance, produce induced current.

Through above-mentioned retention time prolongation method is applied to resonance converter; When input voltage is undesired; The output voltage of resonance converter is sensed primary side; Thereby in magnetizing inductance, produce induced current, the direction of current flow in the primary coil of this faradic flow direction transformer during with the resonance converter operate as normal is consistent.The induced current that is produced makes the electric current that flows through the resonant capacitance Cr in the resonance converter increase, thereby improves the voltage on the resonant capacitance Cr.Like this, the output voltage of resonance converter can remain in certain level and not descend, thereby prolongs the retention time of resonance converter.

In the embodiment shown in Fig. 3 A-3C, 4A-4C and the 5A-5B, all can adopt following formula (1)-(3) to calculate impedor electric current and voltage in the retention time prolongation circuit, no longer repeat here.In addition, in the embodiment shown in Fig. 2 A-2C, 3A-3C, 4A-4C, the 5A-3B, switch element (like Q32, Q34, Q42 etc.) is shown as MOSFET.In other embodiments, these switch elements can also be the switch elements of other types, for example insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT) or the transistor of other types etc.Here be not described further.

Retention time prolongation circuit structure according to embodiment of the present disclosure is simple and reliable, can effectively prolong the retention time of resonance converter, does not reduce the efficient of resonance converter simultaneously.In addition, in other embodiments, can also reduce the switching loss of switch element through the inductance value that improves magnetizing inductance Lm, thereby promote conversion efficiency.

Prolong the transducer that circuit and method can be additional to any kind of (like full-bridge type resonance converter described in the preceding text and semibridge system transducer etc.) according to retention time of embodiment of the present disclosure, need only this transducer and have resonant circuit and both can.

In addition; Retention time prolongation circuit and method according to embodiment of the present disclosure can be applied to the DC-DC power supply; Also can be applied to the AC-DC power supply and (particularly utilize voltage lifting PFC (Power Factor Correction; Power factor correction)) preconditioner is the situation of DC/DC transducer power supply), do not limit here.

More than combine specific embodiment and/or example to describe basic principle of the present disclosure, still, should be understood that the disclosure is not limited to these concrete embodiment and/or examples.In addition; It is pointed out that those of ordinary skill in the art, can understand whole or any parts of device of the present disclosure; And on these disclosed bases, according to concrete the application these parts are modified, substitute and conversion, and still be covered by within the scope of the present disclosure.

In addition; The application's term " comprises ", " comprising " or its any other variant are intended to contain comprising of nonexcludability; Thereby make the process, method, article or the device that comprise a series of key elements not only comprise those key elements; But also comprise other key elements of clearly not listing, or also be included as this process, method, article or device intrinsic key element.Under the situation that do not having much more more restrictions, the key element that limits by statement " comprising ... ", and be not precluded within process, method, article or the device that comprises said key element and also have other identical element.

Claims (11)

1. a retention time that is used for resonance converter prolongs circuit (210,310,410,510), it is characterized in that this retention time prolongs circuit and comprises:

Coil (La2, La3, La4, La5), this coil is coupled to the magnetizing inductance (Lm) of the primary side of the transformer in the said resonance converter;

Impedance component (Lb2, Rb3, Rb4, Lb5), (La4 La5) connects for La2, La3 for this impedance component and said coil; And

Switching circuit (211,311,411,511), this switching circuit is connected in said impedance component (Lb2; Rb3, Rb4 is Lb5) with said coil (La2, La3, La4; La5) between, wherein, when the input voltage of resonance converter is reduced to predetermined threshold, said switching circuit (211; 311,411,511) conducting makes the output voltage of said resonance converter sense said coil (La2 through said magnetizing inductance (Lm); La3, La4 La5) and in said coil produces induced current, and the direction of current flow in the primary coil of this faradic flow direction transformer during with the resonance converter operate as normal is consistent.

2. the retention time according to claim 1 prolongs circuit,

Wherein, Said switching circuit (211) comprise first and second switch elements (Q32, Q42), an end of said impedance component (Lb2) is connected to an end of said coil (La2); And the other end is connected to an end of said first switch element (Q32); The other end of said first switch element (Q32) is connected to an end of said second switch element (Q42), and the other end of said second switch element (Q42) is connected to the other end of said coil (La2), and

Wherein, Said first switch element (Q32) and said second switch element (Q42) also respectively with said resonance converter in controller (101) link to each other; When the input voltage of said resonance converter is reduced to predetermined threshold; Said controller makes said first and second switch elements (Q32, Q42) conducting.

3. the retention time according to claim 2 prolongs circuit; Wherein, (Q32 Q42) is field-effect transistor to said first and second switch elements, and the drain electrode of said first switch element (Q32) is connected to said impedance component; The source electrode of said first switch element (Q32) is connected to the source electrode and the ground connection of said second switch element (Q42); The drain electrode of said second switch element (Q42) is connected to the other end of said coil, and said first and second switch elements (Q32, grid Q42) all is connected to said controller.

4. the retention time according to claim 1 prolongs circuit, and wherein, said switching circuit (311,411) comprises the first switch element (Q33; Q34) and diode bridge circuit, and said first switch element (Q33, end Q34) is connected to said impedance component (Rb3; Rb4) a end, the other end is connected to said diode bridge circuit, and said diode bridge circuit is also connected to said impedance component (Rb3; The other end Rb4) and said coil (La3, two ends La4), and

Said first switch element (Q33, Q34) also with said resonance converter in controller (101) link to each other, wherein, when the input voltage of said resonance converter was reduced to predetermined threshold, said controller made said first switch element (Q33, Q34) conducting.

5. the retention time according to claim 4 prolongs circuit; Wherein, said first switch element (Q34) is a field-effect transistor, and said diode bridge circuit comprises first diode (D44) and second diode (D34); The centre of said coil (La4) is provided with the tap of ground connection, and

Wherein, the drain electrode of said first switch element (Q34) is connected to an end of said impedance component (Rb4), and grid is connected to said controller (101), and source ground and link to each other with said coil (La4), and

Wherein, the anode of said first diode (D44) is connected to an end of said coil, and negative electrode is connected to the said impedor other end, and

Wherein, the anode of said second diode (D34) is connected to the other end of said coil, and negative electrode is connected to the negative electrode of said first diode.

6. retention time according to claim 4 prolongs circuit, and wherein, said first switch element (Q33) is a field-effect transistor, said diode bridge circuit comprise first to fourth diode (D3, D4, D5, D6), and

Wherein, the anode of first diode (D3) is connected to an end of said coil (La3), and negative electrode is connected to an end of said impedance component (Rb3); The anode of second diode (D4) is connected to the other end of said coil (La3), and negative electrode is connected to the negative electrode of first diode (D3); The anode of the 3rd diode (D5) is connected to the anode and the ground connection of the 4th diode (D6), and negative electrode is connected to the anode of first diode (D3); The negative electrode of the 4th diode (D6) is connected to the anode of second diode, and

Wherein, the drain electrode of said first switch element (Q33) is connected to the other end of said impedance component (Rb3), and grid is connected to said controller (101), and source ground.

7. the retention time according to claim 1 prolongs circuit; Wherein, said switching circuit (511) comprises diode full-bridge circuit (D35, D45; D55; D65), said diode full-bridge circuit is connected between the end of said coil (La5) and said impedance component (Lb5), and the other end of said impedance component (Lb5) is connected to the input power supply of said resonance converter.

8. the retention time according to claim 7 prolongs circuit, and wherein, said diode full-bridge circuit comprises first to fourth diode (D35; D45, D55, D65); The anode of first diode (D35) is connected to an end of said coil, and negative electrode is connected to an end of said impedance component (Lb5); The anode of second diode (D45) is connected to the other end of said coil (La5), and negative electrode is connected to the negative electrode of first diode (D35); The anode of the 3rd diode (D55) is connected to the anode and the ground connection of the 4th diode (D65), and negative electrode is connected to the anode of first diode (D35); The negative electrode of the 4th diode (D65) is connected to the anode of second diode (D45).

9. prolong circuit according to each described retention time among the claim 1-8, wherein, (Rb4 Lb5) is inductance element or resistive element to said impedance component for Lb2, Rb3.

10. a resonance converter is characterized in that, this resonance converter comprises according to each described retention time prolongation circuit among the claim 1-9.

11. according to the resonance converter described in the claim 10, wherein, said resonance converter is full-bridge type resonance converter or semibridge system resonance converter.

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