TW201021383A - Efficient insulated DC power conversion device - Google Patents

Abstract

An efficient insulated DC power conversion device comprises a transformer, a first switch, a clamp circuit, an output diode, an output capacitor, and a boost circuit. The output capacitor has a first end and a second end electrically connected to the cathode of the output diode and can be charged by the second winding via the output diode. The boost circuit is electrically connected with two ends of the second winding and the second end of the output capacitor and can be charged by the second winding; in addition, the boost circuit can also charge the output capacitor via the output diode to further boost the voltage drop of the output capacitor. The voltage clamp technique is used to decrease the two terminal voltages of all switches and the diodes, thereby reducing the switch loss; furthermore, with the continuous flow of the inductance, the switches can be switched with zero voltage to reduce switch loss, thereby achieving high output power.

Description

201021383 IX. Description of the Invention: [Technical Field] The present invention relates to a power conversion device, and more particularly to a high performance isolated DC power conversion device. [Prior Art] As shown in FIG. 1 , a boost converter is disclosed in the prior art US Pat. No. 7,161,331 B2, which comprises: a coupling circuit 1 〇, a switch 13 鲁, a first diode 121 a second diode 122, an output diode 123, a first capacitor 141, a second capacitor 142, and an output capacitor 143. The light combining circuit 10 includes a first winding 11, and a second Winding 12. And each of the windings 11, 12 has a polarity point end and a non-polar point end. The polarity point of the first winding 11 is electrically connected to the external power source. The first diode 121 includes an anode electrically connected to a non-polar point end of the first winding u, and a cathode. The second diode 122 includes an anode electrically connected to the cathode of the first diode m, and a cathode electrically connected to the non-polar point end of the second winding 12. The output diode 123 includes an anode electrically connected to a non-polar point end of the second winding 12, and a cathode. The first capacitor 141 is electrically connected between the cathode of the first diode 121 and the ground. The second capacitor 142 is electrically connected between the non-polar point end of the first winding u and the polarity end of the second winding 12. 5 201021383 The output valley 143 is electrically connected between the cathode of the output diode 123 and the ground. The switch 13 is electrically connected between one end of the non-polar point end of the first winding turns and the ground, and is switchable between a conductive state and a non-conductive state. For details of the operation of this circuit, refer to the content of this document, which will not be repeated here. The disadvantage of this boost converter is that there is no electrical isolation function. Therefore, for the power supply equipment using this boost converter and located outdoors, the lightning strike will cause the boost converter to be damaged, and the connected power supply equipment will not be normal. Operation 'is therefore quite inconvenient to use. SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a high-efficiency isolated DC power conversion apparatus which provides high conversion efficiency and has voltage clamping performance and can avoid the above-mentioned conventional drawbacks. The high-efficiency isolated DC power conversion device comprises: a transformer comprising a first winding and a second winding, and each winding has a -first end and a second end, and the first winding of the first winding receives the __ terminal The first switch is electrically connected between the second end of the first winding and the ground and is switchable between a conducting state and a non-conducting state; a clamping circuit comprising a second switch and a series connected in series Clamping the capacitor, and the second switch in series and the clamp capacitor are connected in parallel with the first winding, the second switch can switch between a conducting state and a non-conducting state; a round out diode, including a cathode and an electrical connection An anode of the first end of the second winding 201021383; an output capacitor 'having a first end and a second end electrically connected to the cathode of the output diode and the voltage across the two ends is the output voltage And the output diode is charged by the second winding; and a booster circuit is electrically connected to both ends of the second winding and the second end of the output capacitor, and can be charged by the second winding. And the boost circuit can also pass

The output capacitor is charged by the output diode to further increase the voltage across the output capacitor. The effect of the invention is to use a transformer with isolation function to reduce the degree of lightning damage, and the voltage clamping technology reduces the voltage across all switches and diodes, thereby reducing the conduction and switching losses, and by the inductive freewheeling characteristic, These switches use zero voltage switching to reduce switching losses and achieve high output power. The above and other technical contents, features, and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments. The preferred embodiment of the high-efficiency isolated DC power conversion device of the present invention is suitable for boosting the DC input voltage factory/jV of the external power supply into a DC-to-DC output, and includes: a changer 2 The first switch A, a clamp circuit 3, a ±Α, an output diode, a boost circuit 4, and an output capacitor. b. The transformer 2 includes two windings wound around a core (not shown), dividing the windings and the second winding, wherein the resistance ratio is 201021383 1··. And each winding Z/J, the core has a polarity point end and a non-polar point end, and the polarity point end of the first winding receives the input power. The first switch S7 is connected in series with the first winding LP and is switchable between an on state and a non-conduction state. a factory, where is the second switch & and a clamp capacitor G, and the second switch & and the clamp capacitor G are connected in parallel with the first winding ο, the second The switch & can be switched between a conducting state and a non-conducting state. The output diode A includes an anode electrically connected to a polarity end of the second winding & and a cathode. The first: nc° has a cathode two:: terminal electrically connected to the output diode & and the voltage across the two ends is the output voltage & through the output diode 仏 is the second winding S charging. The boosting circuit 4, 盥 妞 妞 妞 ar ar C0 坌 _ 0 ° —, · both ends of the circuit and the output terminal 电 the first end of the electrical connection, can be awkward, the first winding ^ charging, And the isoindole® can also pass through the output diode

^ , 奋For the output capacitor Cn, IV further increases the cross-voltage of the output capacitor Q. . Charging with the boosting circuit 4; - point and the input (four) capacity c / (four) two winding ^ non-polar body & and - second diode Z) y. The first diode of the child has a cathode and an anode at the end of the sex point. Connected to the second training group [S non-polar, the second capacitor q is electrically connected between the polarity end of a second winding. The anode of the pole body and the anode of the 201021383 have a cathode electrically connected to the anode of the first diode and an anode electrically connected to the second end of the output capacitor C? . Passing one of the first diodes or the second diodes to form a series path 'the first diode and the second capacitor CV' or the second diode Pr, respectively The series path of the second capacitor Cy, the second winding core, and the first capacitor Cr causes the booster circuit 4 to have a bidirectional current path.

When the output diode and the first diode zv are simultaneously turned on, the second diode £)r is non-conductive, and the second winding and the first capacitor perform output capacitance through the output diode. Charging, and the second winding also charges the second capacitor c# via the first diode. When the second diode /) y is turned on, the first diode is not turned on. The second winding L and the second capacitor Cw charge the first capacitor Cy via the second diode. Referring to Fig. 3, according to the switching of the two switches &&, the high-efficiency isolated DC power conversion device operates in seven modes, and each mode will be described below. The Vcsi and %s2 parameters in Fig. 3 represent the voltage of the control terminal of the first switch & and the voltage of the control terminal of the second switch & The parameter represents the excitation current of the transformer 2, and k, L, and discrimination represent the current flowing through the first winding Zp, the current flowing through the second winding b, and the current flowing through the inductor U. The Μ, VS1 parameters respectively represent the flow. The current of the first switch & the voltage of the first switch & the % parameter represents the current flowing through the second switch & the voltage across the second switch & The current through the first diode, the voltage across the first diode 9 201021383 ^, the heart, the ~ parameter represent the voltage flowing across the second diode ~ turbulent, the second diode The parameters respectively pass through the current of the output diode dz and the voltage across the output diode & Mode One (Time: Wl): 参阅 Referring to Figure 4, in this mode, the first switch & has been turned on for a while and the second switch & And in Figure 4, the direction of the current path is indicated in this mode. The parameters in Figure 4 represent [the leakage inductance and the magnetizing inductance of the winding k, and the following is a convenient body for convenience of explanation. In this mode, the output diode A and the first diode are called black, and Non-conducting switch (in this mode: the second switch sentence is indicated by a dashed line and ignores the turn-on voltage of the diode. In this mode, the main action is the output capacitor. The second capacitor ^^ is charged. Output The capacitor C0 is charged: an external power source (the voltage is supplied with current to cause the first winding to be excited, and an induced voltage is generated, and the voltage is induced to the second winding core according to the turns ratio, so the induced voltage on the second winding L For ', and all winding turns, the voltage of the core is positive at the polarity point. Wherein, the second winding induced voltage is equal to #FW) The first capacitor Cy is connected in series to charge the output capacitor C0 via the output diode. The first capacitor cv is charged: at the same time, the second winding core charges the second capacitor via the first diode to clamp the voltage of the second diode, and the second voltage VCF is expressed as vCfr = (1 ) 10 201021383 here In the formula, the current & component of the first winding includes the exciting current ^ and the induction motor 'amplifies the induced current of the second winding ^ according to the ratio, and the induced current value of the first winding 等于 is equal to ^ because The excitation current of the first winding “ “positive slope, and the induced current slope of the first winding & is negative, this complementary characteristic makes the electric U of the first winding 近 close to the square wave, when the excitation inductance and the leakage inductance are properly adjusted. When the value is, the closer the current flowing through the first switch & is, the closer the conduction loss is. Mode 2 (time: id: as shown in Fig. 5) In mode 2, the first switch & The second switch & continues to be non-conducting. In Figure 5, the standard is in this mode, the current path is going, and in mode two, the output diode DZ and the di-polar body Z) w are continuously turned on. The leakage inductance energy is continuously released to the transformer 2, so the second winding core maintains the previous mode operation, and the current of the first winding (4) begins to decrease and charges the parasitic capacitance at both ends of the -_ & The crossover of the switch & starts to rise 'and the second switch & The parasitic capacitance is discharged. Therefore, the two ends of the second opening are also synchronously dropped. The two switches / 2 span and vsl + Vs2 are equal to the voltage and vC / + Fw of the electric dust and the external power supply of the clamped electric power. Second (time: ί23): As shown in FIG. 6, in this mode three, the base diode of the second switch & is turned on and the first call is not turned on, and the current path is marked in this mode in FIG. The other diodes are not conducting. When the parasitic capacitance of the second switch & discharge causes the voltage across the two ends to zero, 11 201021383 The second switch & base diode is turned on, so that the first winding Z The current of /> and the current of the inductor are all introduced into the clamp capacitor Q, so that the voltage VS1 of the first switch && stops rising and clamps here, and the duty cycle of the first switch is defined as d, and The voltage_second theorem calculates the voltage of the clamp capacitor Cx as vcx = V1Nd/(ld) (2) and the highest voltage at both ends of the first switch is vS) = Vm + Vcx _Vs2 = Vjnj / (1 _d) ( 3) Since the energy of the leakage inductance of the first winding is released, the current L of the second winding L is at time point 6 Zero, as the magnetizing current of the first winding core induced release of energy to the second winding, all windings, core voltage is positive 'when the current in the second winding of the heart in a non-polar end point. Start reverse, and because the current on the side of the voltage is much smaller than the low voltage side, and the leakage inductance of the second winding L is limited, the current L of the second winding core increases slowly, and the current path causes the parasitic of the second diode. The capacitor discharges, and charges the parasitic capacitance of the first diode ZV and the output one body Z)z, so that the voltage of the first one body, the voltage of the second diode, and the voltage of the second diode are obtained. The voltage Vcy of the first capacitor CV is VD<V+VDr=Vcy. (4) According to the above formula, the voltages of the first diode and the second diode Dy are clamped together to be 'not affected by leakage inductance energy, and The highest voltage across them is equal to the voltage of the first capacitor core Vc〆 mode four (time: W4): as shown in Figure 7, in this mode 'the first switch & not conducting and the 12th 201021383 two switch & Start to turn on. And in Figure 7, the standard ψ 二 2, T 琛 does not show the direction of the current path in this mode, and in mode 4, only the second diode is turned on. Since the input voltage ^ belongs to low lightning damage, the immersion potential has a 咼 current characteristic, when the base diode of the second switch & is turned on, if the pressure is reduced at both ends of the right pole Too high will result in a large conduction loss. At this time, the 诵坌 町 守 守 第 — 开关 开关 开关 开关 开关 开关 开关 开关 开关 开关 开关 开关 开关 开关 开关 开关 开关 开关 开关 开关 开关 开关 开关 开关 开关 开关 开关 开关Since the current l of the first winding turns to zero at the time point, and starts to

The current is partially received from the inductor Z, resulting in the first winding. The current b increases in the reverse direction.

In the middle of mode four, the electric current U of the first winding 4 is subjected to the total current G of the inductance Z. At this time, the clamping capacitor G starts to discharge, and the second switch A passes through the forward conduction path, clamps the capacitor C, and the current G, the inductance ^ The current ^ and the amount of the excitation current U, the reverse flow to the _ winding is induced to the second winding & the induced voltage of the second winding & the voltage equal to the voltage of the clamped capacitor C, and the second The winding L is connected in series with the second capacitor~ to charge the nth via the second diode & the voltage of the first capacitor Cy can be obtained by combining equations (1) and (2) to vcr = νω + vcw = VmN / (1 - d) (5), therefore, transformer 2 has a bidirectional magnetic circuit characteristic. The current in this mode can compensate for the problem that the switching inductance structure is too small in the duty cycle, resulting in insufficient excitation and the current in the clamp capacitor flows backward. Before the second switch & first, the second open 1 is turned "on", so that the second switch & has zero voltage switching performance. Mode 5 (time: ί4~〇: as shown in Figure 8, in this mode, second Switch & not conducting and the first 13 201021383 switch & not conducting. And marked in Figure 8 In this mode, the direction of the current path, and in mode 5, only the second diode is turned on. Since the leakage current of the first winding turns, the current comes from the clamp capacitor & and the inductor k, when the second When the first non-conduction is performed, the leakage current flowing through the leakage inductance 4 of the first winding 4 is partially obtained by the current of the clamp capacitor ^, and the leakage inductance A of the first winding core is respectively subjected to the parasitic capacitance of the second switch 4. Charging and discharging the parasitic capacitance of the first switch $ to maintain a continuous flow, wherein the voltage relationship between the two switches 5W2 is the same as the mode two principle. " The second winding maintains the pre-mode operation, but the second winding. The flow begins to decrease gradually. Mode 6 (Time: 4: 2: Show 'in this mode six' first switch... body diode-switch & non-conducting. And Figure 9 shows the current flowing in this mode The direction of the path 'and in mode 6' is only the second diode of the second diode: when the parasitic capacitance of happy is discharged to zero volts, the first switch & V, stop rising and clamp the "door"! A switch & Therefore, it can be known that the withstand voltage specification of the first switch & is the same as that of the first switch & mode seven (time ^~,.): as shown in Fig. 10, the switch is turned on in this mode. Turning on & and second in the first-switch ... body diode conduction state off & conduction, forming a zero electricity _ change (four) brother open and limited first - winding ο leakage inductance 14 201021383 4 influence, the first winding 4 The current l starts from the negative direction and turns forward. When the current center amplitude of the first winding Ip is equal to the excitation current, the first winding ^ receives energy again, and the current G of the second winding core is induced to rise. Since the high-voltage side current is much smaller than the low-voltage side and is limited by the leakage inductance, the current L of the second winding core is slowly increased, and the current path causes the parasitic capacitance of the first diode to the output diode to be discharged. And charging the parasitic capacitance of the second diode.

When the parasitic capacitance of the output diode ~ is discharged to zero, the turn-off diode starts to conduct. At this time, the second winding w voltage string (4) capacitance Cy (voltage vcy) is output to the output capacitor & via the output diode Charging, using equation (5), can obtain output voltage 4 equal to vo=vls+ vcr = VinN{2- d)/(1 -d) (6) Define the boost ratio of this circuit architecture to %, the relationship can be Table Gy == N{2-d)f\-d (7) When the first-diode is turned on, the electric current of the first winding is ~ the magnetic current k and the current induced to the second winding core, when the first The winding magnetizing current w gradually rises south, and the induced current gradually decreases from the high point, returning to the mode one. Starting from the following equation, the voltage relationship of the first switch A of equation (3) can be obtained by substituting (6) to obtain vSi = V〇l{2~d)N (8) Experimental results: As shown in Fig. 11-18, The output power for the circuit is _ 叮 each 7L piece 15 201021383 waveform measured results. As shown in FIG. 11 and FIG. 12, the voltage and current waveforms of the two switches &, & respectively, the voltages of the two switches A, & are clamped at about 55v, and the two switches 5; Zero voltage switching effect, and the second switch $ has synchronous rectification characteristics. 2 As shown in Fig. 13, it is the current waveform of the inductor, which can effectively share the excitation current of the first winding ,, and can provide the reverse induced current of the transformer 2 when the second switch & As shown in FIG. 14, the waveform of the current g of the first winding and the current k of the second winding , is compared with the amplitude of the two waveforms, the current of the first winding has a low voltage and a large current, and the current L of the second winding is High voltage and low current characteristics. As shown in Figs. 15 and 16, the voltage % of the first diode and the voltage V yy and current of the first electrode are shown, respectively. The voltages of each other are rated at 300V and lower than the output voltage. Since the current must flow through the leakage inductance of the second winding, the reverse recovery current is sufficiently suppressed. As shown in Fig. 17, in order to output the voltage and current waveforms of the diode, since the on-period is long, there is no Inrush Current phenomenon, so the ripple of the output voltage is reduced. As shown in FIG. 18, three waveforms of the current core of the second winding, the current W of the second capacitor, and the current h of the output diode Dz are illustrated, thereby indicating that the output diode is directly output during the first switching center conduction period. The current of z ίβζ is sent to the output terminal to charge the wheel-out capacitor C0, which can effectively reduce the circulating component of the whole circuit' to further reduce the conduction loss of the first switch & 16 201021383 As shown in Figure 19, the loading and unloading test of the present invention, the loading and unloading test of the load from 50W to 450W, observe the continuous wave variation of the output voltage ^, and the output electric grind does not have a sag with the load drastically changing. The phenomenon, verifying that the voltage regulation capability is stable. As shown in Figure 20, the voltage is 17V, and the conversion efficiency is shown in Figure 4. From the figure, the highest conversion efficiency is about 95. /. And at 500W output, there is still 91°/. The above conversion efficiency. In summary, the preferred embodiment of the present invention has the following advantages: (1) The voltage clamping technique can be used to reduce the breakdown voltage per-off and all the one-pole Dz, ZV, and no reverse high recovery current problems. (2) All switches and diodes have flexible switching characteristics' and the maximum conversion efficiency is approximately 95%. (3) Since the current generated by the two windings includes the induced current and the exciting current, and the slopes of the waveforms of the two windings are opposite, the transformer 2 can accept a lower magnetizing inductance, so the volume of the core and the number of winding turns can be reduced. The press 2 is easy to be wound to reduce weight and cost, and the steel loss and the iron core loss caused by the high current on the low voltage side are also simultaneously reduced. (4) The present invention has an isolation function to reduce the degree of lightning damage compared to conventional architectures. (5) According to theoretical analysis and implementation verification, the maximum voltage that each switch & is subjected to, in the case of a duty cycle of 丨, by equation (8)~=4/(2_^#, can be derived only from the output voltage In relation to the turns ratio, this feature is more suitable for applications in which the DC input voltage varies widely. However, the above description is only a preferred embodiment of the present invention, and when 17 201021383 can limit the scope of implementation of the present invention, That is, the simple equivalent changes and modifications made by the present invention in the scope of the invention and the description of the invention are still within the scope of the present invention. [Fig. 1 is a circuit diagram of a conventional boosting device] 2 is a circuit diagram of a preferred embodiment of the high-performance isolated DC power conversion device of the present invention; FIG. 3 is a timing diagram of the preferred embodiment; FIG. 4 is a circuit diagram of the preferred embodiment, illustrating a mode Figure 5 is a circuit diagram of the preferred embodiment illustrating operation in mode two; 'Figure 6 is a circuit diagram of the preferred embodiment illustrating operation in mode three; ', Figure 7 is the preferred Electric power of the embodiment FIG. 8 is a circuit diagram of the preferred embodiment, illustrating operation in mode 5; FIG. 9 is a circuit diagram of the preferred embodiment, illustrating mode 6 Figure 10 is a circuit diagram of the preferred embodiment, illustrating the operation of the mode from Figure VIII. Figure 11 is an experimental measurement of the preferred embodiment, illustrating the first-on voltage and current waveforms 18 201021383 12 is an experimental measurement diagram of the preferred embodiment, illustrating voltage and current waveforms of the second switch; FIG. 13 is an experimental measurement diagram of the preferred embodiment, illustrating current waveforms and first switches of the inductor FIG. 14 is an experimental measurement diagram of the preferred embodiment, illustrating currents of the first winding and the second winding and voltage waveforms of the first switch; FIG. 15 is an experimental amount of the preferred embodiment The figure shows the voltage and current waveform of the first diode. FIG. 16 is an experimental measurement diagram of the preferred embodiment illustrating the voltage and current waveforms of the second diode. FIG. 17 is a preferred embodiment. Experimental measurement chart of the embodiment, illustrating the output. FIG. 18 is an experimental measurement diagram of the preferred embodiment, illustrating current waveforms of the second winding, the second capacitor, and the wheel-out diode; FIG. 19 is an experimental amount of the preferred embodiment. The map ' illustrates the output voltage and current conditions under different loads; and FIG. 20 is an experimental measurement diagram of the preferred embodiment, illustrating the conversion efficiency. 19 201021383 [Major component symbol description] 2 ....... ...transformer 3 ........- · system circuit 4 ........ boost circuit C〇·... output capacitor

Cy*......••first capacitor

Cw........second capacitor

Cx.........clamping capacitor

Dz .......output diode CV...... 'The first two poles D wide ·...... second diode S]........ 'first switch 5V...·...· Second switch LP.........first winding L s ·...—* second winding

Lx.........inductor factory/7V.........input voltage V〇.........output voltage

20

Claims (1)

201021383 X. Application for Patent Park: Applicable to an external 'and includes: an input voltage of a power-isolated DC power conversion power supply is boosted into an output voltage-winding, and the first end of each winding is connected to the transformer, The first winding and the first winding have a first end and a second end, and the first input receives the input voltage; Φ a first switch, and the first winding is switched between the series and the non-conducting state; a conducting state-clamping circuit comprising a second switch in series and a capacitor and a second switch in series and the clamp capacitor are connected in parallel with the first winding. The second switch can be between a conducting state and a non-conducting state Switching; an output diode comprising: a _± 匕祜g pole and an anode electrically connected to the first end of the second winding, <=!; an output capacitor 'having - electrically connected to the anode Pulling the first end and the second end of the cathode of the diode, and the voltage across the two ends is the output voltage, and can be charged by the second winding through the output diode; and -liter Voltage circuit 'with this The two ends of the two windings are electrically connected to the second end of the output capacitor, and can be charged by the second winding, and the boosting circuit can also charge the output capacitor via the output diode to further boost the output capacitor. 2. The high-voltage isolated DC power conversion device according to the scope of the invention, wherein the boosting circuit includes - electrically connected to the second end of the second winding and the output capacitor The first capacitor between the second end, when the second winding charges the output capacitor via the output diode, the 21st 201021383 electric valley also charges the output capacitor via the round-out diode. The high-efficiency isolated DC power conversion device described in the second aspect of the patent scope: 'where the boost circuit further includes a first diode and a second capacitor, the 黛-_ one body and the first The two capacitors are connected in series between the two ends of the second winding, and the ## two windings are charged, and the second capacitor is permeable to the second diode by the fourth patent according to the scope of the patent application. Isolated DC power supply, set, among them, The boosting circuit further includes a second diode connected between the second capacitor and the electrical connection of the first diode and the second terminal of the output capacitor, and the second capacitor is permeable The first diode is charged to the first capacitor. The conversion device: the high-efficiency isolated DC power supply according to the third item of the patent scope=2, wherein the output diode and the first-diode are simultaneously charged. The output capacitor is charged by the second winding via the output diode: the second capacitor is also non-conducting via the first diode through the high-performance isolated DC power supply® of the second winding range item 4. , f' When the second diode is passed, the first-second pole 7. According to the patent application conversion device, wherein the high-efficiency isolated DC power source is described. The switch and the second switch are not turned on at the same time. 8. According to the patent application range, the clamped performance isolation type DC power supply, the i circuit further includes an inductor connected to the first winding and 22 201021383. . 9_ According to the patent application scope conversion device, wherein the high-efficiency isolated DC power supply of the first winding has a first end of the first winding, a first end of which is a polarity point end, and a coin end is a non-polar point end, The second end of the second winding is a polarity point end 'and the second end of the second winding is a non-polar point end ❿ 23