Power conversion circuit and operation method thereof

Abstract

A power conversion circuit includes a first resonant converter, a second resonant converter and a control device. The control device provides first and second switching signals to the first and second resonant converters. The control device includes first, second and third control modules. The first control module determines a switching frequency corresponding to the first and second switching signals according to an output voltage, a total output current, a predetermined voltage and a predetermined current. The second control module determines a phase shift angle corresponding to the first and second switching signals according to first and second currents of the first and second resonant converters. The third control module generates the first and second switching signals according to the switching frequency and the phase shift angle, and controls an interleaved phase angle between the first and second switching signals according to the switching frequency and a resonant frequency.

Description

[Technical Field]

[0001] This invention relates to a power conversion circuit, and more particularly to a power conversion circuit and its operation method. [Previous Technology]

[0002] Generally, the LLC architecture can meet the requirements for high-power, high-efficiency applications. However, in high-current applications, when the secondary side operates in discontinuous current mode (DCM), it can lead to a large current ripple and require a sufficiently large capacitor in parallel. Therefore, a new design is needed to improve the aforementioned problems. [Summary of the Invention]

[0003] The present invention provides a power conversion circuit and its operation method, thereby balancing the current of the power conversion circuit, reducing the current ripple of the power conversion circuit, and thus reducing the number of input and output capacitors.

[0004] This invention provides a power conversion circuit, including a first resonant converter, a second resonant converter, and a control device. The first resonant converter includes a first transformer, a first resonant inductor, a first resonant capacitor, a first bridge switching circuit, and a first rectifier circuit. The first transformer has a first primary winding and a second primary winding. The first resonant inductor and the first resonant capacitor are connected in series and connected to the first primary winding. The first bridge switching circuit is connected to the first resonant inductor, the first resonant capacitor, and the first primary winding. The first primary winding is connected to the first rectifier circuit. The second resonant converter includes a second transformer, a second resonant inductor, a second resonant capacitor, a second bridge switching circuit, and a second rectifier circuit. The second transformer has a second primary winding and a second secondary winding. The second resonant inductor and the second resonant capacitor are connected in series and connected to the second primary winding. The second bridge switching circuit is connected to the second resonant inductor, the second resonant capacitor, and the second primary winding. The second secondary winding is connected to the second rectifier circuit. The first bridge switching circuit and the second bridge switching circuit receive input voltage. The output terminals of the first rectifier circuit and the second rectifier circuit are connected in parallel. The first and second rectifier circuits output output voltages. The control device provides multiple first switching signals to the first bridge switching circuit and multiple second switching signals to the second bridge switching circuit. The control device includes a first control module, a second control module, and a third control module. The first control module determines the switching frequency of the corresponding first and second switching signals based on the output voltage, total output current, preset voltage, and preset current. The second control module determines the phase shift angle of the corresponding first and second switching signals based on the first current flowing through the first resonant inductor and the second current flowing through the second resonant inductor. The third control module generates the first and second switching signals based on the switching frequency and phase shift angle, and controls the interleaving phase angle between the corresponding first and second switching signals based on the switching frequency and resonant frequency.

[0005] This invention provides an operation method for a power conversion circuit, wherein the power conversion circuit includes a first resonant converter and a second resonant converter. The first resonant converter includes a first transformer, a first resonant inductor, a first resonant capacitor, a first bridge switching circuit, and a first rectifier circuit. The first transformer has a first primary winding and a first secondary winding. The first resonant inductor and the first resonant capacitor are connected in series and connected to the first primary winding. The first bridge switching circuit is connected to the first resonant inductor, the first resonant capacitor, and the first primary winding. The first secondary winding is connected to the first rectifier circuit. The second resonant converter includes a second transformer, a second resonant inductor, a second resonant capacitor, a second bridge switching circuit, and a second rectifier circuit. The second transformer has a second primary winding and a second secondary winding. The second resonant inductor and the second resonant capacitor are connected in series and connected to the second primary winding. The second bridge switching circuit is connected to the second resonant inductor, the second resonant capacitor, and the second primary winding. The second secondary winding is connected to the second rectifier circuit. The first bridge switching circuit and the second bridge switching circuit receive input voltage. The output terminals of the first rectifier circuit and the second rectifier circuit are connected in parallel. The first and second rectifier circuits output an output voltage. The above operation method includes the following steps: A first control module receives the output voltage and total output current, and determines the switching frequency of the corresponding power conversion circuit based on the output voltage, total output current, preset voltage, and preset current. A second control module receives a first current flowing through the first resonant inductor and a second current flowing through the second resonant inductor, and determines the phase shift angle of the corresponding power conversion circuit based on the first and second currents. A third control module generates multiple first switching signals and multiple second switching signals based on the switching frequency and phase shift angle. The third control module controls the interleaving phase angle between the corresponding first and second switching signals based on the switching frequency and resonant frequency.

[0006] The power conversion circuit and its operation method disclosed in this invention receive the output voltage and total output current through a first control module, and determine the switching frequency of the corresponding power conversion circuit based on the output voltage, total output current, preset voltage, and preset current. A second control module determines the phase shift angle of the corresponding power conversion circuit based on the first current flowing through the first resonant inductor and the second current flowing through the second resonant inductor. A third control module generates multiple first switching signals and multiple second switching signals based on the switching frequency and phase shift angle, and controls the interleaving phase angle between the corresponding first switching signals and second switching signals based on the switching frequency and resonant frequency. In this way, the current in the power conversion circuit can be effectively balanced, current ripple reduced, and the number of input and output capacitors reduced.

Implementation Method

[0007] In the various embodiments listed below, the same or similar elements or components will be represented by the same reference numerals.

[0008] Figure 1 is a schematic diagram of a power conversion circuit according to one embodiment of the present invention. Figure 2 is a detailed schematic diagram of a power conversion circuit according to one embodiment of the present invention. Figure 3 is a schematic diagram of a control device according to one embodiment of the present invention. Referring to Figures 1, 2 and 3, the power conversion circuit 100 may include a first resonant converter 110, a second resonant converter 120 and a control device 300.

[0009] The first resonant converter 110 can receive an input voltage Vi and output an output voltage Vo. Further, the first resonant converter 110 may have an input terminal IT1 and an output terminal OT1. The positive terminal of the input terminal IT1 of the first resonant converter 110 is coupled to the positive terminal of the input voltage Vi. The negative terminal of the input terminal IT1 of the first resonant converter 110 is coupled to the negative terminal of the input voltage Vi. The positive terminal of the output terminal OT1 of the first resonant converter 110 is coupled to the positive terminal of the output voltage Vo. The negative terminal of the output terminal OT1 of the first resonant converter 110 is coupled to the negative terminal of the output voltage Vo. Additionally, the first resonant converter 110 includes a first bridge switching circuit 111, a first resonant capacitor Cr1, a first resonant inductor Lr1, a first transformer T1, and a first rectifier circuit 112. The first bridge switching circuit 111 has a first terminal, a second terminal, a third terminal, and a fourth terminal. The first terminal of the first bridge switching circuit 111 is coupled to the positive terminal of the input terminal IT1 of the first resonant converter 110. The second terminal of the first bridge switching circuit 111 is coupled to the negative terminal of the input terminal IT1 of the first resonant converter 110.

[0010] In some embodiments, the first bridge switching circuit 111 may be a full-bridge switching circuit. More specifically, the first bridge switching circuit 111 may include switches QA_P1, QB_P1, QC_P1, and QD_P1. Switch QA_P1 has a first terminal, a second terminal, and a control terminal. The first terminal of switch QA_P1 is coupled to the first terminal of the first bridge switching circuit 111. The second terminal of switch QA_P1 is coupled to the third terminal of the first bridge switching circuit 111. The control terminal of switch QA_P1 receives a switching signal CS1_P1. Switch QB_P1 has a first terminal, a second terminal, and a control terminal. The first terminal of switch QB_P1 is coupled to the first terminal of QA_P1. The second terminal of switch QB_P1 is coupled to the fourth terminal of the first bridge switching circuit 111. The control terminal of switch QB_P1 receives a switching signal CS2_P1.

[0011] Switch QC_P1 has a first terminal, a second terminal, and a control terminal. The first terminal of switch QC_P1 is coupled to the second terminal of switch QA_P1. The second terminal of switch QC_P1 is coupled to the second terminal of the first bridge switch circuit 111. The control terminal of switch QC_P1 receives the switching signal CS3_P1. Switch QD_P1 has a first terminal, a second terminal, and a control terminal. The first terminal of switch QD_P1 is coupled to the second terminal of QB_P1. The second terminal of switch QD_P1 is coupled to the second terminal of switch QC_P1. The control terminal of switch QD_P1 receives the switching signal CS4_P1.

[0012] The first resonant capacitor Cr1 has a first terminal and a second terminal. The first terminal of the first resonant capacitor Cr1 is coupled to the third terminal of the first bridge switching circuit 111 (e.g., the second terminal of switch QA_P1). The second terminal of the first resonant capacitor Cr1 generates a first current I1. The first resonant inductor Lr1 has a first terminal and a second terminal. The first terminal of the first resonant inductor Lr1 is coupled to the second terminal of the first resonant capacitor Cr1. That is, the first resonant inductor Lr1 and the first resonant capacitor Cr1 are connected in series. In some embodiments, the first resonant converter 110 may further include a magnetizing inductor Lm1, as shown in Figure 2. The magnetizing inductor Lm1 has a first terminal and a second terminal. The first terminal of the magnetizing inductor Lm1 is coupled to the second terminal of the first resonant inductor Lr1. The second terminal of the magnetizing inductor Lm1 is coupled to the fourth terminal of the first bridge switching circuit 111 (e.g., the second terminal of switch QB_P1).

[0013] The first transformer T1 has a first terminal, a second terminal, a third terminal, and a fourth terminal. The first terminal of the first transformer T1 is coupled to the second terminal of the first resonant inductor Lr1. The second terminal of the first transformer T1 is coupled to the fourth terminal of the first bridge switching circuit 111 (e.g., the second terminal of switch QB_P1). Further, the first transformer T1 may include a first primary winding NP1 and a first primary winding NS1. The first primary winding NP1 has a first terminal and a second terminal. The first terminal of the first primary winding NP1 is coupled to the first terminal of the first transformer T1. The second terminal of the first primary winding NP1 is coupled to the second terminal of the first transformer T1. The first primary winding NS1 has a first terminal and a second terminal. The first terminal of the first primary winding NS1 is coupled to the third terminal of the first transformer T1. The second terminal of the first primary winding NS1 is coupled to the fourth terminal of the first transformer T1.

[0014] The first rectifier circuit 112 has a first terminal, a second terminal, a third terminal, and a fourth terminal. The first terminal of the first rectifier circuit 112 is coupled to the third terminal of the first transformer T1. The second terminal of the first rectifier circuit 112 is coupled to the fourth terminal of the first transformer T1. The third terminal of the first rectifier circuit 112 is coupled to the positive terminal of the output terminal OT1 of the first resonant converter 110 and outputs a current I_P1. The fourth terminal of the first rectifier circuit 112 is coupled to the negative terminal of the output terminal OT1 of the first resonant converter 110.

[0015] In some embodiments, the first rectifier circuit 112 may be a full-bridge switching circuit. More specifically, the first rectifier circuit 112 includes diodes D1, D2, D3, and D4. Diode D1 has an anode and a cathode. The anode of diode D1 is coupled to a first terminal of the first rectifier circuit 112. The cathode of diode D1 is coupled to a third terminal of the first rectifier circuit 112. Diode D2 has an anode and a cathode. The anode of diode D2 is coupled to a second terminal of the first rectifier circuit 112. The cathode of diode D2 is coupled to the cathode of diode D1. Diode D3 has an anode and a cathode. The anode of diode D3 is coupled to ground. The cathode of diode D3 is coupled to the anode of diode D1. Diode D4 has an anode and a cathode. The anode of diode D4 is coupled to the anode of diode D3. The cathode of diode D4 is coupled to the anode of diode D2. The first rectifier circuit 112 generates and outputs current I_P1.

[0016] The second resonant converter 120 has an input terminal IT2 and an output terminal OT2. The positive terminal of the input terminal IT2 of the second resonant converter 120 is coupled to the positive terminal of the input terminal IT1 of the first resonant converter 110. The negative terminal of the input terminal IT2 of the second resonant converter 120 is coupled to the negative terminal of the input terminal IT1 of the first resonant converter 110. The positive terminal of the output terminal OT2 of the second resonant converter 120 is coupled to the positive terminal of the output terminal OT1 of the first resonant converter 110. The negative terminal of the output terminal OT2 of the second resonant converter 120 is coupled to the negative terminal of the output terminal OT1 of the first resonant converter 110. That is, the first resonant converter 110 and the second resonant converter 120 are connected in parallel.

[0017] Additionally, the second resonant converter 120 includes a second bridge switching circuit 121, a second resonant capacitor Cr2, a second resonant inductor Lr2, a second transformer T2, and a second rectifier circuit 122. The second bridge switching circuit 121 has a first terminal, a second terminal, a third terminal, and a fourth terminal. The first terminal of the second bridge switching circuit 121 is coupled to the positive terminal of the input terminal IT2 of the second resonant converter 120. The second terminal of the second bridge switching circuit 121 is coupled to the negative terminal of the input terminal IT2 of the second resonant converter 120.

[0018] In some embodiments, the second bridge switching circuit 121 may be a full-bridge switching circuit. More specifically, the second bridge switching circuit 121 may include switches QA_P2, QB_P2, QC_P2, and QD_P2. Switch QA_P2 has a first terminal, a second terminal, and a control terminal. The first terminal of switch QA_P2 is coupled to the first terminal of the second bridge switching circuit 121. The second terminal of switch QA_P2 is coupled to the third terminal of the second bridge switching circuit 121. The control terminal of switch QA_P2 receives a switching signal CS1_P2. Switch QB_P2 has a first terminal, a second terminal, and a control terminal. The first terminal of switch QB_P2 is coupled to the first terminal of QA_P2. The second terminal of switch QB_P2 is coupled to the fourth terminal of the second bridge switching circuit 121. The control terminal of switch QB_P2 receives a switching signal CS2_P2.

[0019] Switch QC_P2 has a first terminal, a second terminal, and a control terminal. The first terminal of switch QC_P2 is coupled to the second terminal of switch QA_P2. The first terminal of switch QC_P2 is coupled to the second terminal of the second bridge switch circuit 121. The control terminal of switch QC_P2 receives the switching signal CS3_P2. Switch QD_P2 has a first terminal, a second terminal, and a control terminal. The first terminal of switch QD_P2 is coupled to the second terminal of QB_P2. The second terminal of switch QD_P2 is coupled to the second terminal of switch QC_P2. The control terminal of switch QD_P2 receives the switching signal CS4_P2.

[0020] The second resonant capacitor Cr2 has a first terminal and a second terminal. The first terminal of the second resonant capacitor Cr2 is coupled to the third terminal of the second bridge switching circuit 121 (e.g., the second terminal of switch QA_P2). The second terminal of the second resonant capacitor Cr2 generates a second current I2. The second resonant inductor Lr2 has a first terminal and a second terminal. The first terminal of the second resonant inductor Lr2 is coupled to the second terminal of the second resonant capacitor Cr2. That is, the second resonant inductor Lr2 and the second resonant capacitor Cr2 are connected in series. In some embodiments, the second resonant converter 120 may further include a magnetizing inductor Lm2, as shown in Figure 2. The magnetizing inductor Lm2 has a first terminal and a second terminal. The first terminal of the magnetizing inductor Lm2 is coupled to the second terminal of the second resonant inductor Lr2. The second terminal of the magnetizing inductor Lm2 is coupled to the fourth terminal of the second bridge switching circuit 121 (e.g., the second terminal of switch Q_P2).

[0021] The second transformer T2 has a first terminal, a second terminal, a third terminal, and a fourth terminal. The first terminal of the second transformer T2 is coupled to the second terminal of the first resonant inductor Lr1. The second terminal of the second transformer T2 is coupled to the fourth terminal of the second bridge switching circuit 121 (e.g., the second terminal of switch QB_P2). Further, the second transformer T2 may include a second primary winding NP2 and a second secondary winding NS2. The second primary winding NP2 has a first terminal and a second terminal. The first terminal of the second primary winding NP2 is coupled to the first terminal of the second transformer T2. The second terminal of the second primary winding NP2 is coupled to the second terminal of the second transformer T2. The second secondary winding NS2 has a first terminal and a second terminal. The first terminal of the second secondary winding NS2 is coupled to the third terminal of the second transformer T2. The second terminal of the second secondary winding NS2 is coupled to the fourth terminal of the second transformer T2.

[0022] The second rectifier circuit 122 has a first terminal, a second terminal, a third terminal, and a fourth terminal. The first terminal of the second rectifier circuit 122 is coupled to the third terminal of the second transformer T2. The second terminal of the second rectifier circuit 122 is coupled to the fourth terminal of the second transformer T2. The third terminal of the second rectifier circuit 122 is coupled to the positive terminal of the output terminal OT2 of the second resonant converter 120 and outputs a current I_P2. The fourth terminal of the second rectifier circuit 122 is coupled to the negative terminal of the output terminal OT2 of the second resonant converter 120. That is, the output terminals of the first rectifier circuit 112 and the second rectifier circuit 122 are connected in parallel, and the first rectifier circuit 112 and the second rectifier circuit 122 output an output voltage Vo.

[0023] In some embodiments, the second bridge switching circuit 121 can be a full-bridge switching circuit. Further, the second rectifier circuit 122 includes diodes D5, D6, D7, and D8. Diode D5 has an anode and a cathode. The anode of diode D5 is coupled to a first terminal of the second rectifier circuit 122. The cathode of diode D5 is coupled to a third terminal of the second rectifier circuit 122. Diode D6 has an anode and a cathode. The anode of diode D6 is coupled to a second terminal of the second rectifier circuit 122. The cathode of diode D6 is coupled to the cathode of diode D5. Diode D7 has an anode and a cathode. The anode of diode D7 is coupled to ground. The cathode of diode D7 is coupled to the anode of diode D5. Diode D8 has an anode and a cathode. The anode of diode D8 is coupled to the anode of diode D7. The cathode of diode D8 is coupled to the anode of diode D6. The second rectifier circuit 122 generates and outputs current I_P2.

[0024] In some embodiments, the power conversion circuit 100 may further include a capacitor Cin, a capacitor Cout, and a load Lo. The capacitor Cin has a first terminal and a second terminal. The first terminal of the capacitor Cin is coupled to the positive terminal of the input voltage Vi. The second terminal of the capacitor Cin is coupled to the negative terminal of the input voltage Vi. The capacitor Cout has a first terminal and a second terminal. The first terminal of the capacitor Cout is coupled to the positive terminal of the output terminal OT1 of the first resonant converter 110, the positive terminal of the output terminal OT2 of the second resonant converter 120, and the positive terminal of the output voltage Vo. The second terminal of the capacitor Cout is coupled to the negative terminal of the output terminal OT1 of the first resonant converter 110, the negative terminal of the output terminal OT2 of the second resonant converter 120, and the negative terminal of the output voltage Vo. The load Lo has a first terminal and a second terminal. The first terminal of the load Lo is coupled to the positive terminal of the output terminal OT1 of the first resonant converter 110 and the positive terminal of the output terminal OT2 of the second resonant converter 120. The first terminal of the load Lo is coupled to the negative terminal of the output terminal OT1 of the first resonant converter 110 and the negative terminal of the output terminal OT2 of the second resonant converter 120. The first resonant converter 110 outputs current I_P1, the second resonant converter 120 outputs current I_P2, and the capacitor Cout can output current ICout. The total output current Io includes currents I_P1, I_P2, and the current ICout flowing through capacitor Cout, i.e., Io = I_P1 + I_P2 + ICout.

[0025] Furthermore, in some embodiments, when switching signals CS1_P1 and CS4_P1 are at high voltage levels, switching signals CS2_P1 and CS3_P1 are at low voltage levels. When switching signals CS1_P1 and CS4_P1 are at low voltage levels, switching signals CS2_P1 and CS3_P1 are at high voltage levels. That is, switches QA_P1 and QD_P1 can be turned on or off together, while switches QB_P1 and QC_P1 can be turned on or off together.

[0026] In addition, in some embodiments, when switching signals CS1_P2 and CS4_P2 are at high voltage levels, switching signals CS2_P2 and CS3_P2 are at low voltage levels. When switching signals CS1_P2 and CS4_P2 are at low voltage levels, switching signals CS2_P2 and CS3_P2 are at high voltage levels. That is, switches QA_P2 and QD_P2 can be turned on or off together, while switches QB_P2 and QC_P2 can be turned on or off together.

[0027] In some embodiments, each of switches QA_P1, QB_P1, QC_P1, QD_P1, QA_P2, QB_P2, QC_P2, and QD_P2 may be a transistor. In other embodiments, each of switches QA_P1, QB_P1, QC_P1, QD_P1, QA_P2, QB_P2, QC_P2, and QD_P2 may include a transistor, a diode, and a capacitor, and the coupling method of the transistor, diode, and capacitor is shown in Figure 2, so it will not be described again here.

[0028] The control device 300 is adapted to connect and control the first resonant converter 110 and the second resonant converter 120 of the power conversion circuit 100 in Figures 1 and 2. As shown in Figure 3, the control device 300 can provide switching signals CS1_P1~CS4_P1 to the first bridge switching circuit 111, and provide switching signals CS1_P2~CS4_P2 to the second bridge switching circuit 121. The control device 300 may include a first control module 310, a second control module 320, and a third control module 330.

[0029] The first control module 310 can be coupled to the capacitor Cout of the power conversion circuit 100. The power conversion circuit 100 may include one or more sensors that sense the total output current Io, the first current I1 flowing through the first resonant inductor Lr1, and the second current I2 flowing through the second resonant inductor Lr2. The first control module 310 can receive the output voltage Vo and the total output current Io of the power conversion circuit 100. Then, the first control module 310 can determine the switching frequency fs of the corresponding switching signals CS1_P1~CS4_P1 and switching signals CS1_P2~CS4_P2 based on the output voltage Vo, the total output current Io, the preset voltage Vcmd, and the preset current Icmd. In some embodiments, the preset voltage Vcmd and the preset current Icmd can be adjusted by the user according to their needs.

[0030] In some embodiments, the first control module 310 can perform a subtraction calculation (i.e., Vcmd-Vo) based on a preset voltage Vcmd and an output voltage Vo to obtain a first value. Next, the first control module 310 can perform a subtraction calculation (i.e., Icmd-Io) based on a preset current Icmd and a total output current Io to obtain a second value. Afterwards, the first control module 310 can determine the aforementioned switching frequency fs based on the first and second values.

[0031] Furthermore, the first control module 310 can compare the first value with the second value to confirm whether the first value is less than the second value. When it is confirmed that the first value is less than the second value, the first control module 310 can determine the switching frequency fs based on the first value. When the first value is not less than the second value (i.e., the second value is less than the first value), the first control module 310 can determine the switching frequency fs based on the second value. In this way, by determining the switching frequency fs through the first control module 310, the switching frequencies of the first resonant converter 110 and the second resonant converter 120 of the power conversion circuit 100 can be the same.

[0032] In this embodiment, the first control module 310 may include a first low-pass filter 311, a second low-pass filter 312, a first subtractor 313, a second subtractor 314, a first proportional integral (PI) controller 315, a second proportional integral controller 316, a first limiter 317, a second limiter 318, and a decision unit 319.

[0033] The first low-pass filter 311 has an input terminal and an output terminal. The input terminal of the first low-pass filter 311 can receive the output voltage Vo. The output terminal of the first low-pass filter 311 can generate the low-pass filtered output voltage Vo. The second low-pass filter 312 has an input terminal and an output terminal. The input terminal of the second low-pass filter 312 can receive the total output current Io. The output terminal of the second low-pass filter 312 can generate the low-pass filtered total output current Io.

[0034] The first subtractor 313 has a first input terminal (e.g., a positive input terminal), a second input terminal (e.g., a negative input terminal), and an output terminal. The first input terminal of the first subtractor 313 receives a preset voltage Vcmd. The second input terminal of the first subtractor 313 is coupled to the output terminal of the first low-pass filter 311.

[0035] The second subtractor 314 has a first input terminal (e.g., a positive input terminal), a second input terminal (e.g., a negative input terminal), and an output terminal. The first input terminal of the second subtractor 314 receives a preset current Icmd. The second input terminal of the second subtractor 314 is coupled to the output terminal of the second low-pass filter 312.

[0036] A first proportional-integral controller 315 has an input terminal and an output terminal. The input terminal of the first proportional-integral controller 315 is coupled to the output terminal of the first subtractor 313. A second proportional-integral controller 316 has an input terminal and an output terminal. The input terminal of the second proportional-integral controller 316 is coupled to the output terminal of the second subtractor 314. A first limiter 317 has an input terminal and an output terminal. The input terminal of the first limiter 317 is coupled to the output terminal of the first proportional-integral controller 315. A second limiter 318 has an input terminal and an output terminal. The input terminal of the second limiter 318 is coupled to the output terminal of the second proportional-integral controller 316. A decision unit 319 has a first input terminal, a second input terminal, and an output terminal. The first input terminal of the decision unit 319 is coupled to the output terminal of the first limiter 317. The second input terminal of the decision unit 319 is coupled to the output terminal of the second limiter 318. The decision unit 319 outputs a switching frequency fs.

[0037] The second control module 320 can receive a first current I1 flowing through the first resonant inductor Lr1 (as shown in Figures 1 and 2) and a second current I2 flowing through the second resonant inductor Lr2 (as shown in Figures 1 and 2). For example, one or more sensors sense the first current I1 and the second current I2. Then, the second control module 320 can determine the phase shift angle PH of the corresponding switching signals CS1_P1~CS4_P1 and switching signals CS1_P2~CS4_P2 based on the first current I1 flowing through the first resonant inductor Lr1 and the second current I2 flowing through the second resonant inductor Lr2.

[0038] In some embodiments, the second control module 320 can determine the corresponding phase shift angle PH by subtracting the first current I1 from the second current I2 (i.e., I1-I2). For example, when the first current I1 is greater than the second current I2, the phase shift angle PH is negative. When the first current I1 is less than the second current I2, the phase shift angle PH is positive.

[0039] In some embodiments, the second control module 320 may include a first low-pass filter 321, a second low-pass filter 322, a subtractor 323, a proportional-integral controller 324, and a limiter 325.

[0040] A first low-pass filter 321 has an input terminal and an output terminal. The input terminal of the first low-pass filter 321 can receive a first current I1. A second low-pass filter 322 has an input terminal and an output terminal. The input terminal of the second low-pass filter 322 can receive a second current I2. A subtractor 323 has a first input terminal (e.g., a positive input terminal), a second input terminal (e.g., a negative input terminal), and an output terminal. The first input terminal of the subtractor 323 is coupled to the output terminal of the first low-pass filter 321. The second input terminal of the subtractor 323 is coupled to the output terminal of the second low-pass filter 322. A proportional-integral controller 324 has an input terminal and an output terminal. The input terminal of the proportional-integral controller 324 is coupled to the output terminal of the subtractor 323. A limiter 325 has an input terminal and an output terminal. The input terminal of the limiter 325 is coupled to the output terminal of the proportional-integral controller 324. The output terminal of the limiter 325 outputs a phase shift angle PH.

[0041] The third control module 330 can be coupled to the first control module 310, the second control module 320, the first bridge switching circuit 111, and the second bridge switching circuit 121. For example, the third control module 330 can be coupled to switches QA_1 to QD_P2 of the first bridge switching circuit 111 and the second bridge switching circuit 121. The third control module 330 can generate switching signals CS1_P1 to CS4_P1 and switching signals CS1_P2 to CS4_P2 according to the switching frequency fs and the phase shift angle PH. In some embodiments, the phase shift angle PH can correspond to the first equivalent responsibility period Deff1 or the second equivalent responsibility period Deff2. For example, when the phase shift angle PH is zero, the first equivalent responsibility period Deff1 or the second equivalent responsibility period Deff2 is 50%. When the phase shift angle PH increases, the first equivalent responsibility period Deff1 or the second equivalent responsibility period Deff2 decreases.

[0042] In some embodiments, when the first current I1 is greater than the second current I2, the phase shift angle PH output by the second control module 320 is negative. Then, the third control module 330 generates corresponding switching signals CS1_P1~CS4_P1 and CS1_P2~CS4_P2 based on the switching frequency fs and the negative phase shift angle PH. For example, the third control module 330 can reduce the first equivalent duty period Deff1 of the switching signals CS1_P1~CS4_P1 of the corresponding power conversion circuit 100 switches QA_P1~QD_P1 (i.e., the first equivalent duty period Deff1 is less than 50%), and the third control module 330 can maintain the second equivalent duty period Deff2 between the switching signals CS1_P2…CS4_P2 of the corresponding power conversion circuit 100 switches QA_P2~QD_P2.

[0043] In some embodiments, when the first current I1 is less than the second current I2, the phase shift angle PH output by the second control module 320 is positive. Then, the third control module 330 generates corresponding switching signals CS1_P1~CS4_P1 and CS1_P2~CS4_P2 based on the switching frequency fs and the positive phase shift angle PH. For example, the third control module 330 can reduce the second equivalent duty period Deff2 of the switching signals CS1_P2~CS4_P2 of the corresponding power conversion circuit 100 switches QA_P2~QD_P2 (i.e., the second equivalent duty period Deff2 is less than 50%), and the third control module 330 can maintain the equivalent duty period Deff2 of the switching signals CS1_P1~CS4_P1 of the corresponding power conversion circuit 100 switches QA_P1~QD_P1 at 50%.

[0044] Furthermore, the third control module 330 can control the interleaved phase angle between the corresponding switching signals CS1_P1~CS4_P1 and switching signals CS1_P2~CS4_P2 based on the switching frequency fs and the resonant frequency. In this embodiment, the aforementioned resonant frequency can be calculated, for example, from the first resonant capacitor Cr1 and the first resonant inductor Lr1 or the second resonant capacitor Cr2 and the second resonant inductor Lr2 of the power conversion circuit 100. For example, the resonant frequency can be 1 / 2 or 1 / 2. In some embodiments, the inductance value of the first resonant inductor Lr1 is the same as the inductance value of the second resonant inductor Lr2. Therefore, the resonant frequency can be 1 / 2.

[0045] Furthermore, the third control module 330 can confirm whether the switching frequency fs is greater than or equal to the resonant frequency. When it is confirmed that the switching frequency fs is greater than or equal to the resonant frequency, the third control module 330 controls the aforementioned interleaved phase angle to be the equivalent switch-off interleaved phase angle between the switching signals CS1_P1…CS4_P1 and the switching signals CS1_P2…CS4_P2. Additionally, the aforementioned equivalent switch-off interleaved phase angle can be 90 degrees. For example, the third control module 330 can at least interleave the switching signals CS4_P1 and CS4_P2 of the corresponding power conversion circuit 100 switches QD_P1 and QD_P2 from a high voltage level to a low voltage level by 90 degrees. In this way, it can be ensured that the currents I_P1 and I_P2 of the power conversion circuit 100 are out of phase by 90 degrees, minimizing the current overlap area and reducing the ripple of the current ICout.

[0046] When it is confirmed that the switching frequency fs is not greater than or equal to (i.e. less than) the resonant frequency, the third control module 330 controls the aforementioned interleaved phase angle to be the equivalent switch conduction interleaved phase angle between the switching signals CS1_P1…CS4_P1 and the switching signals CS1_P2…CS4_P2. Furthermore, the aforementioned equivalent switch conduction interleaved phase angle can be 90 degrees. For example, the third control module 330 can at least interleave the timing of the switching signals CS1_P1 and CS1_P2 of the corresponding power conversion circuit 100 switches QA_P1 and QA_P2 from a low voltage level to a high voltage level by 90 degrees. In this way, it can be ensured that the currents I_P1 and I_P2 of the power conversion circuit 100 are out of phase by 90 degrees, minimizing the current overlap area and reducing the ripple of the current ICout.

[0047] In some embodiments, the third control module 330 may include an adder 331, a subtractor 332, a first limiter 333, a second limiter 334 and a switching signal generation circuit 335.

[0048] Adder 331 has a first input terminal (e.g., a positive input terminal), a second input terminal (e.g., a positive input terminal), and an output terminal. The first input terminal of adder 331 receives a phase shift angle PH. The second input terminal of adder 331 receives a preset phase shift angle. Subtractor 332 has a first input terminal (e.g., a positive input terminal), a second input terminal (e.g., a negative input terminal), and an output terminal. The first input terminal of subtractor 332 receives a preset phase shift angle. The second input terminal of subtractor 332 receives a phase shift angle PH.

[0049] The first limiter 333 has an input terminal and an output terminal. The input terminal of the first limiter 333 is coupled to the output terminal of the adder 331. The output terminal of the first limiter 333 outputs a first equivalent duty period Deff1. The second limiter 334 has an input terminal and an output terminal. The input terminal of the second limiter 334 is coupled to the output terminal of the subtractor 332. The output terminal of the second limiter 334 outputs a second equivalent duty period Deff2. The switching signal generation circuit 335 is coupled to the first control module 310, the output terminal of the first limiter 333, and the output terminal of the second limiter 334. The switching signal generation circuit 335 receives the switching frequency fs, the first equivalent duty period Deff1, and the second equivalent duty period Deff2. The switching signal generation circuit 335 can generate switching signals CS1_P1~CS4_P1 according to the switching frequency fs and the first equivalent duty period Deff1, and the switching signal generation circuit 335 can generate switching signals CS1_P2~CS4_P2 according to the switching frequency fs and the second equivalent duty period Deff2, and control the interleaved phase angle.

[0050] Figure 4 is a waveform diagram of current ICout, current I_P1, current I_P2, switching signal CS1_P1, switching signal CS4_P1, switching signal CS1_P2, and switching signal CS4_P2 when the switching frequency is greater than or equal to the resonant frequency, according to one embodiment of the present invention. In Figure 4, the label "Ts" represents the switching period, and the switching period Ts is 1 / switching frequency fs (i.e., Ts = 1 / fs). As can be seen in Figure 4, there is a phase shift angle PH between switching signal CS1_P2 and switching signal CS4_P2. Therefore, in the example in Figure 4, the second equivalent duty period Deff2 is less than 50%. Furthermore, as can be seen in Figure 4, the interleaved phase angle is the equivalent switch-off interleaved phase angle between the switching signals CS4_P1 and CS1_P2, and the equivalent switch-off interleaved phase angle is 90 degrees. This ensures that the currents I_P1 and I_P2 are out of phase by 90 degrees, resulting in a smaller current ICout ripple, i.e., the current ICout is approximately 9.7 Arms.

[0051] Figure 5 is a waveform diagram of current ICout, current I_P1, current I_P2, switching signal CS1_P1, switching signal CS4_P1, switching signal CS1_P2, and switching signal CS4_P2 when the switching frequency is less than the resonant frequency, according to one embodiment of the present invention. In Figure 5, the label "Ts" represents the switching period, and the switching period Ts is 1 / switching frequency fs (i.e., Ts = 1 / fs). As can be seen in Figure 5, there is a phase shift angle PH between switching signal CS1_P2 and switching signal CS4_P2. Therefore, in the example in Figure 5, the second equivalent duty period Deff2 is less than 50%. Furthermore, as can be seen in Figure 5, the staggered phase angle is the equivalent switch conduction staggered phase angle of the switching signals CS1_P1 and CS1_P2, and the equivalent switch conduction staggered phase angle is 90 degrees. This ensures that the currents I_P1 and I_P2 are out of phase by 90 degrees, resulting in a smaller current ICout ripple, i.e., the current ICout is approximately 2 Arms.

[0052] Figure 6 is a flowchart of the operation method of a power conversion circuit according to one embodiment of the present invention. The operation method of the power conversion circuit of this embodiment is applicable to the power conversion circuit 100 shown in Figures 1 and 2 and the control device 300 shown in Figure 3. In step S602, the output voltage and total output current are received through the first control module, and the switching frequency of the corresponding power conversion circuit is determined based on the output voltage, total output current, preset voltage and preset current.

[0053] In step S604, the second control module receives the first current flowing through the first resonant inductor and the second current flowing through the second resonant inductor, and determines the phase shift angle of the corresponding power conversion circuit based on the first current and the second current. Further, step S604 may include the second control module performing a subtraction calculation on the first current and the second current to determine the phase shift angle of the corresponding power conversion circuit.

[0054] In step S606, a plurality of first switching signals and a plurality of second switching signals are generated by the third control module according to the switching frequency and phase shift angle. In step S608, the interleaving phase angle between the first switching signals and the second switching signals is controlled by the third control module according to the switching frequency and the resonant frequency. In some embodiments, when the switching frequency is greater than or equal to the resonant frequency, the interleaving phase angle is the equivalent switch-off interleaving phase angle of the first switching signal and the second switching signal. Furthermore, the aforementioned equivalent switch-off interleaving phase angle is 90 degrees. In some embodiments, when the switching frequency is less than the resonant frequency, the interleaving phase angle is the equivalent switch-on interleaving phase angle of the first switching signal and the second switching signal. Furthermore, the aforementioned equivalent switch-on interleaving phase angle is 90 degrees.

[0055] Figure 7 is a detailed flowchart of step S602 in Figure 6. In step S702, the first control module subtracts the output voltage from the preset voltage to obtain a first value. In step S704, the first control module subtracts the total output current from the preset current to obtain a second value. In step S706, the first control module determines the switching frequency based on the first and second values. Further, step S706 may include steps S708, S710, and S712.

[0056] In step S708, the first control module confirms whether the first value is less than the second value. When it is confirmed that the first value is less than the second value, the process proceeds to step S710, where the first control module determines the switching frequency based on the first value. When it is confirmed that the first value is not less than the second value, the process proceeds to step S712, where the first control module determines the switching frequency based on the second value.

[0057] Figure 8 is a detailed flowchart of step S608 in Figure 6. In step S802, the third control module confirms whether the switching frequency is greater than or equal to the resonant frequency. When the switching frequency is confirmed to be greater than or equal to the resonant frequency, the process proceeds to step S804, where the third control module controls the interleaved phase angle to be the equivalent switch-off interleaved phase angle between the first switching signal and the second switching signal. The aforementioned equivalent switch-off interleaved phase angle can be 90 degrees. When the switching frequency is confirmed to be not greater than or equal to (i.e., less than) the resonant frequency, the process proceeds to step S806, where the third control module controls the interleaved phase angle to be the equivalent switch-on interleaved phase angle between the first switching signal and the second switching signal. The aforementioned equivalent switch-off interleaved phase angle can be 90 degrees.

[0058] In some embodiments, the power conversion circuit 100 may further include a third resonant converter, the circuit architecture of which is the same as that of the first resonant converter 110 and the second resonant converter 120 and is connected in parallel with the first resonant converter 110 and the second resonant converter 120. In this embodiment, the equivalent switch-off or-on interleaved phase angle may be 60 degrees. In some embodiments, the power conversion circuit 100 may include N resonant converters and the N resonant converters are connected in parallel, the equivalent switch-off or-on interleaved phase angle may be (180 / N) degrees.

[0059] It is worth noting that the order of the steps in Figures 6, 7, and 8 is for illustrative purposes only and is not intended to limit the order of steps in the embodiments of the present invention. Furthermore, the order of the steps can be changed by the user according to their needs. Additionally, without departing from the spirit and scope of the present invention, additional steps may be added or fewer steps may be used.

[0060] In summary, the power conversion circuit and its operation method disclosed in this invention receive the output voltage and total output current through a first control module, and determine the switching frequency of the corresponding power conversion circuit based on the output voltage, total output current, preset voltage, and preset current. A second control module determines the phase shift angle of the corresponding power conversion circuit based on the first current flowing through the first resonant inductor and the second current flowing through the second resonant inductor. A third control module generates multiple first switching signals and multiple second switching signals based on the switching frequency and phase shift angle, and controls the interleaving phase angle between the corresponding first switching signals and second switching signals based on the switching frequency and resonant frequency. In this way, the current of the resonant converter can be effectively balanced, reducing the current distortion of the resonant converter, thereby reducing the number of input and output capacitors.

[0061] Although the present invention has been disclosed above by way of embodiments, it is not intended to limit the scope of the present invention. Anyone with ordinary knowledge in the art can make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims. [Simplified Explanation of the Diagram]

[0062] Figure 1 is a schematic diagram of a power conversion circuit according to an embodiment of the present invention. Figure 2 is a detailed schematic diagram of a power conversion circuit according to an embodiment of the present invention. Figure 3 is a schematic diagram of a control device according to an embodiment of the present invention. Figure 4 is a waveform diagram of current ICout, current I_P1, current I_P2, switching signal CS1_P1, switching signal CS4_P1, switching signal CS1_P2 and switching signal CS4_P2 when the switching frequency is greater than or equal to the resonant frequency according to an embodiment of the present invention. Figure 5 is a waveform diagram of current ICout, current I_P1, current I_P2, switching signal CS1_P1, switching signal CS4_P1, switching signal CS1_P2 and switching signal CS4_P2 when the switching frequency is less than the resonant frequency according to an embodiment of the present invention. Figure 6 is a flowchart of an operation method of the control device according to an embodiment of the present invention. Figure 7 is a detailed flowchart of step S602 in Figure 6. Figure 8 is a detailed flowchart of step S608 in Figure 6.

Claims

1. A power conversion circuit, comprising: A first resonant converter includes a first transformer, a first resonant inductor, a first resonant capacitor, a first bridge switching circuit, and a first rectifier circuit. The first transformer has a first primary winding and a first secondary winding. The first resonant inductor and the first resonant capacitor are connected in series and connected to the first primary winding. The first bridge switching circuit is connected to the first resonant inductor, the first resonant capacitor, and the first primary winding. The first secondary winding is connected to the first rectifier circuit. A second resonant converter includes a second transformer, a second resonant inductor, a second resonant capacitor, a second bridge switching circuit, and a second rectifier circuit. The second transformer has a second primary winding and a second secondary winding. The second resonant inductor and the second resonant capacitor are connected in series and connected to the second primary winding. The second bridge switching circuit is connected to the second resonant inductor, the second resonant capacitor, and the second primary winding. The second secondary winding is connected to the second rectifier circuit. The first bridge switching circuit and the second bridge switching circuit receive an input voltage. The output terminals of the first rectifier circuit and the second rectifier circuit are connected in parallel. The first rectifier circuit and the second rectifier circuit output an output voltage. The device includes a control unit that provides multiple first switching signals to the first bridge switching circuit and multiple second switching signals to the second bridge switching circuit, comprising: a first control module that determines a switching frequency corresponding to the first switching signals and the second switching signals based on the output voltage, a total output current, a preset voltage, and a preset current; a second control module that determines a phase shift angle corresponding to the first switching signals and the second switching signals based on a first current flowing through the first resonant inductor and a second current flowing through the second resonant inductor; and a third control module that generates the first switching signals and the second switching signals based on the switching frequency and the phase shift angle, and controls an interleaved phase angle between the first switching signals and the second switching signals based on the switching frequency and a resonant frequency.

2. The power conversion circuit as claimed in claim 1, wherein when the switching frequency is greater than or equal to the resonant frequency, the interleaved phase angle is the equivalent switching off interleaved phase angle of the first switching signals and the second switching signals.

3. The power conversion circuit as described in claim 2, wherein the equivalent switch cutoff staggered phase angle is 90 degrees.

4. The power conversion circuit as claimed in claim 1, wherein when the switching frequency is less than the resonant frequency, the interleaved phase angle is the equivalent switching interleaved phase angle of the first switching signals and the second switching signals.

5. The power conversion circuit as described in claim 4, wherein the equivalent switch conduction phase angle is 90 degrees.

6. The power conversion circuit as claimed in claim 1, wherein the first bridge switching circuit and the first rectifier circuit are full-bridge switching circuits.

7. The power conversion circuit as described in claim 6, wherein the third control module comprises: An adder has a first input, a second input, and an output. The first input of the adder receives the phase shift angle, and the second input of the adder receives a preset phase shift angle. A subtractor has a first input, a second input, and an output. The first input of the subtractor receives the preset phase shift angle, and the second input of the subtractor receives the phase shift angle. A first limiter has an input and an output. The input of the first limiter is coupled to the output of the adder, and the output of the first limiter outputs a first equivalent duty cycle. A second limiter has an input terminal and an output terminal, the input terminal of the second limiter is coupled to the output terminal of the subtractor, and the output terminal of the second limiter outputs a second equivalent duty cycle; A switching signal generation circuit is coupled to the first control module, the output terminal of the first limiter and the output terminal of the second limiter, and receives the switching frequency, the first equivalent duty period and the second equivalent duty period. The switching signal generation circuit generates the first switching signals according to the switching frequency and the first equivalent duty period, and generates the second switching signals according to the switching frequency and the second equivalent duty period and controls the interleaved phase angle.

8. The power conversion circuit as claimed in claim 1, wherein the first control module performs a subtraction calculation on the output voltage and the preset voltage to obtain a first value, the first control module performs the subtraction calculation on the total output current and the preset current to obtain a second value, and the first control module determines the switching frequency based on the first value and the second value.

9. The power conversion circuit as described in claim 8, wherein the first control module confirms whether the first value is less than the second value; when the first value is confirmed to be less than the second value, the first control module determines the switching frequency based on the first value; when the first value is confirmed to be not less than the second value, the first control module determines the switching frequency based on the second value.

10. The power conversion circuit as claimed in claim 1, wherein the first control module comprises: A first low-pass filter has an input terminal and an output terminal, wherein the input terminal of the first low-pass filter receives the output voltage; A second low-pass filter has an input terminal and an output terminal, the input terminal of the second low-pass filter receiving the total output current; a first subtractor has a first input terminal, a second input terminal and an output terminal, the first input terminal of the first subtractor being coupled to the output terminal of the first low-pass filter, the second input terminal of the first subtractor receiving the preset voltage; a second subtractor has a first input terminal, a second input terminal and an output terminal, the first input terminal of the second subtractor being coupled to the output terminal of the second low-pass filter, the second input terminal of the second subtractor receiving the preset current; A first proportional-integral controller has an input terminal and an output terminal, wherein the input terminal of the first proportional-integral controller is coupled to the output terminal of the first subtractor; A second proportional-integral controller having an input terminal and an output terminal, the input terminal of the second proportional-integral controller being coupled to the output terminal of the second subtractor; a first limiter having an input terminal and an output terminal, the input terminal of the first limiter being coupled to the output terminal of the first proportional-integral controller; a second limiter having an input terminal and an output terminal, the input terminal of the second limiter being coupled to the output terminal of the second proportional-integral controller; And a decision unit having a first input terminal, a second input terminal and an output terminal, the first input terminal of the decision unit being coupled to the output terminal of the first limiter, the second input terminal of the decision unit being coupled to the output terminal of the second limiter, and the decision unit outputting the switching frequency.

11. The power conversion circuit as claimed in claim 1, wherein the second control module performs a subtraction calculation on the first current and the second current to determine the corresponding phase shift angle.

12. The power conversion circuit as claimed in claim 1, wherein the second control module comprises: A first low-pass filter has an input terminal and an output terminal, wherein the input terminal of the first low-pass filter receives the first current; A second low-pass filter having an input terminal and an output terminal, the input terminal of the second low-pass filter receiving the second current; a subtractor having a first input terminal, a second input terminal and an output terminal, the first input terminal of the subtractor being coupled to the output terminal of the second low-pass filter, and the second input terminal of the subtractor being coupled to the output terminal of the first low-pass filter; A proportional-integral controller has an input terminal and an output terminal, the input terminal of the proportional-integral controller being coupled to the output terminal of the subtractor; a limiter has an input terminal and an output terminal, the input terminal of the limiter being coupled to the output terminal of the proportional-integral controller, and the output terminal of the limiter outputting the phase shift angle.

13. A method of operating a power conversion circuit, wherein the power conversion circuit includes a first resonant converter and a second resonant converter, the first resonant converter including a first transformer, a first resonant inductor, a first resonant capacitor, a first bridge switching circuit and a first rectifier circuit, the first transformer having a first primary winding and a first secondary winding, the first resonant inductor and the first resonant capacitor being connected in series and connected to the first primary winding, the first bridge switching circuit being connected to the first resonant inductor, the first resonant capacitor and the first primary winding, the first secondary winding being connected to the first rectifier circuit, and the second resonant converter including a second transformer and a first resonant converter. The system comprises two resonant inductors, a second resonant capacitor, a second bridge switching circuit, and a second rectifier circuit. The second transformer has a second primary winding and a second secondary winding. The second resonant inductor and the second resonant capacitor are connected in series and to the second primary winding. The second bridge switching circuit is connected to the second resonant inductor, the second resonant capacitor, and the second primary winding. The second secondary winding is connected to the second rectifier circuit. The first and second bridge switching circuits receive an input voltage. The output terminals of the first and second rectifier circuits are connected in parallel. The first and second rectifier circuits output an output voltage. The operation method includes: A first control module receives the output voltage and a total output current, and determines the switching frequency corresponding to the power conversion circuit based on the output voltage, the total output current, a preset voltage, and a preset current. A second control module receives a first current flowing through the first resonant inductor and a second current flowing through the second resonant inductor, and determines a phase shift angle corresponding to the power conversion circuit based on the first current and the second current. A third control module generates a plurality of first switching signals and a plurality of second switching signals based on the switching frequency and the phase shift angle. The third control module also controls an interleaved phase angle between the first switching signals and the second switching signals based on the switching frequency and a resonant frequency.

14. The method of operating the power conversion circuit as claimed in claim 13, wherein when the switching frequency is greater than or equal to the resonant frequency, the interleaved phase angle is the equivalent switching off interleaved phase angle of the first switching signals and the second switching signals.

15. The method of operating the power conversion circuit as described in claim 14, wherein the equivalent switch cut-off staggered phase angle is 90 degrees.

16. The method of operating the power conversion circuit as claimed in claim 13, wherein when the switching frequency is less than the resonant frequency, the interleaved phase angle is the equivalent switching-on interleaved phase angle of the first switching signals and the second switching signals.

17. The method of operating the power conversion circuit as described in claim 16, wherein the equivalent switch conduction phase angle is 90 degrees.

18. The method of operating the power conversion circuit as described in claim 13, wherein the step of determining the switching frequency corresponding to the power conversion circuit based on the output voltage, the total output current, the preset voltage, and the preset current includes: The first control module performs a subtraction calculation between the output voltage and the preset voltage to obtain a first value; The first control module performs the subtraction calculation between the total output current and the preset current to obtain a second value; and the first control module determines the switching frequency based on the first value and the second value.

19. The method of operating the power conversion circuit as described in claim 18, wherein the step of the first control module determining the switching frequency based on the first value and the second value includes: The first control module confirms whether the first value is less than the second value; when it is confirmed that the first value is less than the second value, the first control module determines the switching frequency based on the first value; and when it is confirmed that the first value is not less than the second value, the first control module determines the switching frequency based on the second value.

20. A method of operating the power conversion circuit as described in claim 13, wherein the step of determining the phase shift angle corresponding to the power conversion circuit based on the first current and the second current includes: The second control module performs a subtraction calculation between the first current and the second current to determine the phase shift angle.

Images