A resonant converter

Abstract

This application proposes a resonant converter. The resonant converter includes a primary-side switching circuit, a resonant circuit, a transformer circuit, and a secondary-side switching circuit. A plurality of resonant slots in the resonant circuit are star-connected to a plurality of output nodes of the primary-side switching circuit. Each of the plurality of transformers in the transformer circuit includes a primary-side winding and a secondary-side winding. These primary-side windings are delta-connected to the plurality of resonant slots. A plurality of input nodes in the secondary-side switching circuit are star-connected to the secondary-side windings of the transformer circuit. This application reduces magnetic flux density through the configuration of the plurality of resonant slots, thereby reducing core losses and achieving good current balance.

Description

Technical Field

[0001] This application relates to the technical field of power converters, and more particularly to a resonant converter. Prior Technology

[0002] In low-voltage, high-current applications such as charging piles, energy storage systems, and AI servers, power supply circuits often use a three-phase interleaved topology to distribute current stress. When there are characteristic errors between circuit components, the current in each phase will become unbalanced, thus requiring a current sharing system to balance the current in each phase. However, the additional current sharing system not only increases the overall size of the power supply circuit but also increases its production cost.

[0003] Therefore, how to balance the current of each phase without increasing the product size and production cost of the power supply circuit is one of the problems that needs to be solved in this field. Summary of the Invention

[0004] To address the aforementioned technical problems, this application proposes a resonant converter that can achieve good current balance without the need for an additional current sharing system and reduce core losses.

[0005] To achieve one of the above objectives, this application proposes a resonant converter comprising an input circuit, a primary-side switching circuit, a resonant circuit, a transformer circuit, a secondary-side switching circuit, and an output circuit. The input circuit provides an input voltage. The primary-side switching circuit is coupled to the input circuit and includes a first output node, a second output node, and a third output node. The resonant circuit includes a plurality of resonant slots. Each of the plurality of resonant slots includes a resonant capacitor and a resonant inductor connected in series. The plurality of resonant slots are star-connected to the first output node, the second output node, and the third output node. The transformer circuit has a plurality of transformers. Each of the plurality of transformers includes a primary-side winding and a secondary-side winding. The primary-side windings are delta-connected to the plurality of resonant slots. The secondary-side switching circuit is coupled to the transformer circuit and includes a first input node, a second input node, and a third input node. The first input node, the second input node, and the third input node are connected in a star configuration to the secondary windings of the transformer circuit. The output circuit is coupled to the secondary switching circuit and generates an output voltage.

[0006] Based on the above, the resonant converter of this application can reduce the magnetic flux density by configuring a plurality of such resonant slots, thereby reducing the magnetic core loss, and can have a good current balance effect when there are characteristic errors in the circuit elements. Simple Explanation of the Diagram

[0007] Figure 1 is a schematic diagram of a power supply circuit according to an embodiment of this application; Figure 2 is a schematic diagram of an embodiment of the resonant converter according to an embodiment of this application; Figure 3 is a schematic diagram of a second embodiment of the resonant converter according to an embodiment of this application; Figure 4 is a schematic diagram of Embodiment 3 of the resonant converter according to the present application; Figure 5 is a schematic diagram of Embodiment 4 of the resonant converter according to the present application; Figure 6 is a schematic diagram of a control signal embodiment according to an embodiment of this application; Figure 7 is a schematic diagram of an embodiment of the dead time according to an embodiment of this application; Figure 8 is a schematic diagram of a second embodiment of the control signal according to an embodiment of this application; Figure 9 is a comparison diagram of the three-phase current errors of the resonant converter and the full-bridge-full-bridge resonant converter according to the embodiments of this application; Figure 10A is a perspective view of an integrated magnetic core module according to an embodiment of this application; Figure 10B is another perspective view of an integrated magnetic core module according to an embodiment of this application; Figure 10C is a schematic cross-sectional view of an integrated magnetic core module according to an embodiment of this application; Figure 10D is a schematic cross-sectional view of an integrated magnetic core module according to an embodiment of this application; Figure 11 is another perspective view of an integrated magnetic core module according to an embodiment of this application; Figure 12 is another cross-sectional view of an integrated magnetic core module according to an embodiment of this application. Implementation

[0008] Please refer to Figures 1 and 2. Figure 1 is a schematic diagram of a power supply circuit according to an embodiment of this application, and Figure 2 is a schematic diagram of an embodiment of a resonant converter according to an embodiment of this application. The power supply circuit 1 may include at least a resonant converter 10 and a control circuit 20. The resonant converter 10 is electrically connected to the control circuit 20. The resonant converter 10 is a DC-to-DC converter used to output DC voltage to an electrically connected load or circuit. For example, it outputs DC voltage to a voltage regulator (VR) circuit. The control circuit 20 is used to provide control signals required for the operation of the resonant converter 10. For example, control signals S1 to S12. The control circuit 20 is, for example, a microcontroller, and this application is not limited thereto.

[0009] The resonant converter 10 includes an input circuit 100, a primary-side switching circuit 200, a resonant circuit 300, a transformer circuit 400, a secondary-side switching circuit 500, and an output circuit 600. The secondary-side switching circuit 500 includes a first input node D, a second input node E, and a third input node F.

[0010] The input circuit 100 includes a voltage source Vs and an input capacitor Cin. The voltage source Vs provides the input voltage. The two ends of the input capacitor Cin are coupled to the voltage source Vs, that is, the input capacitor Cin and the voltage source Vs are connected in parallel and coupled.

[0011] The primary-side switching circuit 200 is coupled to the input circuit 100. The primary-side switching circuit 200 includes a first bridge arm 210, a second bridge arm 220, and a third bridge arm 230. The first bridge arm 210, the second bridge arm 220, and the third bridge arm 230 are connected in parallel. The first bridge arm 210 includes a first switching unit SW1 and a second switching unit SW2 connected in series, with a first output node A located between the first switching unit SW1 and the second switching unit SW2. The first terminal of the first switching unit SW1 is coupled to the first terminal of the input capacitor Cin, and the second terminal of the first switching unit SW1 is coupled to the first output node A. The control terminal of the first switching unit SW1 receives the control signal S1. The first terminal of the second switching unit SW2 is coupled to the first output node A, and the second terminal of the second switching unit SW2 is coupled to the second terminal of the input capacitor Cin. The control terminal of the second switching unit SW2 receives the control signal S2. The second bridge arm 220 includes a third switch unit SW3 and a fourth switch unit SW4 connected in series, with the second output node B located between the third switch unit SW3 and the fourth switch unit SW4. The first terminal of the third switch unit SW3 is coupled to the first terminal of the input capacitor Cin, and the second terminal of the third switch unit SW3 is coupled to the second output node B. The control terminal of the third switch unit SW3 receives the control signal S3. The first terminal of the fourth switch unit SW4 is coupled to the second output node B, and the second terminal of the fourth switch unit SW4 is coupled to the second terminal of the input capacitor Cin. The control terminal of the fourth switch unit SW4 receives the control signal S4. The third bridge arm 230 includes a fifth switch unit SW5 and a sixth switch unit SW6 connected in series, with the third output node C located between the fifth switch unit SW5 and the sixth switch unit SW6. The first terminal of the fifth switch unit SW5 is coupled to the first terminal of the input capacitor Cin, and the second terminal of the fifth switch unit SW5 is coupled to the third output node C. The control terminal of the fifth switch unit SW5 receives the control signal S5. The first terminal of the sixth switching unit SW6 is coupled to the third output node C, the second terminal of the sixth switching unit SW6 is coupled to the second terminal of the input capacitor Cin, and the control terminal of the sixth switching unit SW6 receives the control signal S6.

[0012] The resonant circuit 300 includes a plurality of resonant slots. Each of the plurality of resonant slots includes a resonant capacitor and a resonant inductor connected in series. The plurality of resonant slots are coupled to the primary-side switching circuit 200 in a wye connection. Further, the resonant circuit 300 includes a first resonant slot 310, a second resonant slot 320, and a third resonant slot 330. The first resonant slot 310 includes a first resonant inductor Lr1 and a first resonant capacitor Cr1. A first terminal of the first resonant inductor Lr1 is coupled to the first output node A, and a second terminal of the first resonant inductor Lr1 is coupled to the first terminal of the first resonant capacitor Cr1. The second terminal of the first resonant capacitor Cr1 is coupled to the primary side of the transformer circuit 400. The second resonant slot 320 includes a second resonant inductor Lr2 and a second resonant capacitor Cr2. A first terminal of the second resonant inductor Lr2 is coupled to the second output node B, and a second terminal of the second resonant inductor Lr2 is coupled to the first terminal of the second resonant capacitor Cr2. The second terminal of the second resonant capacitor Cr2 is coupled to the primary side of the transformer circuit 400. The third resonant slot 330 includes a third resonant inductor Lr3 and a third resonant capacitor Cr3. The first terminal of the third resonant inductor Lr3 is coupled to the third output node C, and the second terminal of the third resonant inductor Lr3 is coupled to the first terminal of the third resonant capacitor Cr3. The second terminal of the third resonant capacitor Cr3 is coupled to the primary side of the transformer circuit 400. In this embodiment, the first resonant inductor Lr1, the second resonant inductor Lr2, and the third resonant inductor Lr3 are coupled to the first output node A, the second output node B, and the third output node C in a star connection. The first resonant capacitor Cr1, the second resonant capacitor Cr2, and the third resonant capacitor Cr3 are coupled to the primary side of the transformer circuit 400 in a star connection.

[0013] The transformer circuit 400 includes a first transformer T1, a second transformer T2, and a third transformer T3. Node G1 is located between the first resonant capacitor Cr1 and the primary side of the first transformer T1. Node G2 is located between the second resonant capacitor Cr2 and the primary side of the second transformer T2. Node G3 is located between the third resonant capacitor Cr3 and the primary side of the third transformer T3. The first transformer T1 has a primary winding Np1, a secondary winding Ns1, and a magnetizing inductor Lm1. The first end of the primary winding Np1 is coupled to node G1, and the second end of the primary winding Np1 is coupled to node G2. The magnetizing inductor Lm1 is coupled between the first and second ends of the primary winding Np1. The first end of the secondary winding Ns1 is coupled to the first input node D, and the second end of the secondary winding Ns1 is coupled to the second transformer T2. The second transformer T2 has a primary winding Np2, a secondary winding Ns2, and a magnetizing inductor Lm2. The first end of the primary winding Np2 is coupled to node G2, and the second end of the primary winding Np2 is coupled to node G3. The magnetizing inductor Lm2 is coupled between the first and second ends of the primary winding Np2. The first end of the secondary winding Ns2 is coupled to the second input node E, and the second end of the secondary winding Ns1 is coupled to the third transformer T3. The third transformer T3 has a primary winding Np3, a secondary winding Ns3, and a magnetizing inductor Lm3. The first end of the primary winding Np3 is coupled to node G3, and the second end of the primary winding Np3 is coupled to node G1. The magnetizing inductor Lm3 is coupled between the first and second ends of the primary winding Np3. The first end of the secondary winding Ns3 is coupled to the third input node F, and the second end of the secondary winding Ns1 is coupled to the second end of the secondary winding Ns1 of the first transformer T1 and the second end of the secondary winding Ns2 of the second transformer T2. In this embodiment, the primary winding Np1 of the first transformer T1, the primary winding Np2 of the second transformer T2, and the primary winding Np3 of the third transformer T3 are coupled to each other in a delta connection. The secondary winding Ns1 of the first transformer T1, the secondary winding Ns2 of the second transformer T2, and the secondary winding Ns3 of the third transformer T3 are coupled to the secondary switching circuit 500 in a star connection.

[0014] The secondary-side switching circuit 500 includes a first rectifier unit 510, a second rectifier unit 520, and a third rectifier unit 530. The first rectifier unit 510, the second rectifier unit 520, and the third rectifier unit 530 are connected in parallel and coupled to each other. The first rectifier unit 510 includes a seventh switch unit SW7 and an eighth switch unit SW8 connected in series. The first input node D is located between the seventh switch unit SW7 and the eighth switch unit SW8. The first terminal of the seventh switch unit SW7 is coupled to the output circuit 600, and the second terminal of the seventh switch unit SW7 is coupled to the first input node D. The control terminal of the seventh switch unit SW7 receives a control signal S7. The first terminal of the eighth switch unit SW8 is coupled to the first input node D, and the second terminal of the eighth switch unit SW8 is coupled to the output circuit 600. The control terminal of the eighth switch unit SW8 receives a control signal S8. The second rectifier unit 520 includes a ninth switch unit SW9 and a tenth switch unit SW10 connected in series. The second input node E is located between the ninth switch unit SW9 and the tenth switch unit SW10. The first terminal of the ninth switch unit SW9 is coupled to the output circuit 600, and the second terminal of the ninth switch unit SW9 is coupled to the second input node E. The control terminal of the ninth switch unit SW9 receives the control signal S9. The first terminal of the tenth switch unit SW10 is coupled to the second input node E, and the second terminal of the tenth switch unit SW10 is coupled to the output circuit 600. The control terminal of the tenth switch unit SW10 receives the control signal S10. The third rectifier unit 530 includes an eleventh switch unit SW11 and a twelfth switch unit SW12 connected in series. The third input node F is located between the eleventh switch unit SW11 and the twelfth switch unit SW12. The first terminal of the eleventh switch unit SW11 is coupled to the output circuit 600, and the second terminal of the eleventh switch unit SW11 is coupled to the third input node F. The control terminal of the eleventh switch unit SW11 receives the control signal S11. The first terminal of the twelfth switching unit SW12 is coupled to the third input node F, and the second terminal of the twelfth switching unit SW12 is coupled to the output circuit 600. The control terminal of the twelfth switching unit SW12 receives the control signal S12. In this embodiment, the first input node D, the second input node E, and the third input node F are coupled to the secondary side of the transformer circuit 400 in a star connection.

[0015] In one embodiment, the first switching unit SW1 to the twelfth switching unit SW12 may be a metal-oxide-semiconductor field-effect transistor (MOSFET), a trench MOSFET, or an insulated gate bipolar transistor (IGBT), and this application is not limited thereto.

[0016] The output circuit 600 is coupled to the secondary-side switching circuit 500 and includes an output capacitor Co and an output resistor Ro connected in parallel. The first terminals of the output capacitor Co and the output resistor Ro are coupled to the first terminals of the seventh switching unit SW7, the ninth switching unit SW9, and the eleventh switching unit SW11. The second terminals of the output capacitor Co and the output resistor Ro are coupled to the second terminals of the eighth switching unit SW8, the tenth switching unit SW10, and the twelfth switching unit SW12. The output circuit 600 is used to generate an output voltage to the coupled load.

[0017] Please refer to Figure 3, which is a schematic diagram of a second embodiment of the resonant converter according to an embodiment of this application. In Figures 2 and 3, components with the same component symbols have the same function, and therefore will not be described again here. The difference between Figure 3 and Figure 2 is that the resonant converter 11 includes the input circuit 100, the primary-side switching circuit 200, the resonant circuit 301, the transformer circuit 400, the secondary-side switching circuit 500, and the output circuit 600. In this embodiment, a node H is included between the second end of the first resonant inductor Lr1 and the first end of the first resonant capacitor Cr1, and the second end of the primary winding Np3 of the third transformer T3 is coupled to the node H. Therefore, in this embodiment, the primary winding Np1, the primary winding Np2, the primary winding Np3, the first resonant capacitor Cr1, the second resonant capacitor Cr2, and the third resonant capacitor Cr3 are coupled to each other in a delta connection. The first resonant inductor Lr1, the second resonant inductor Lr2, and the third resonant inductor Lr3 are coupled to the primary-side switching circuit 200 in a star configuration.

[0018] Please refer to Figure 4, which is a schematic diagram of a third embodiment of the resonant converter according to an embodiment of this application. In Figures 2 and 4, components with the same component symbols have the same function, and therefore will not be described again here. The difference between Figure 4 and Figure 2 is that the resonant converter 12 includes the input circuit 100, the primary-side switching circuit 200, the resonant circuit 300, the transformer circuit 400, the secondary-side switching circuit 500, and the output circuit 600. In this embodiment, the second end of the primary winding Np3 of the third transformer T3 is coupled to the first output node A. Therefore, in this embodiment, the primary winding Np1 of the first transformer T1, the primary winding Np2 of the second transformer T2, the primary winding Np3 of the third transformer T3, the first resonant capacitor Cr1, the second resonant capacitor Cr2, the third resonant capacitor Cr3, the first resonant inductor Lr1, the second resonant inductor Lr2, and the third resonant inductor Lr3 are mutually coupled in a delta connection.

[0019] Please refer to Figure 5, which is a schematic diagram of a fourth embodiment of the resonant converter according to an embodiment of this application. In Figures 2 and 5, components with the same component symbols have the same function, and therefore will not be described again here. The difference between Figure 5 and Figure 2 is that the resonant converter 13 includes the input circuit 100, the primary-side switching circuit 200, the resonant circuit 303, the transformer circuit 400, the secondary-side switching circuit 500, and the output circuit 600.

[0020] The resonant circuit 303 includes a first resonant slot 340, a second resonant slot 350, and a third resonant slot 360. The first resonant slot 340 includes a first resonant inductor Lr1 and a first resonant capacitor Cr1. Node K is located between the first resonant capacitor Cr1 and the first resonant inductor Lr1. The first terminal of the first resonant capacitor Cr1 is coupled to the first output node A, and the second terminal of the first resonant capacitor Cr1 is coupled to node K. The first terminal of the first resonant inductor Lr1 is coupled to node K, and the second terminal of the first resonant inductor Lr1 is coupled to the first terminal of the primary winding Np1 of the transformer circuit 400. The second resonant slot 350 includes a second resonant inductor Lr2 and a second resonant capacitor Cr2. The first terminal of the second resonant capacitor Cr2 is coupled to the second output node B, and the second terminal of the second resonant capacitor Cr2 is coupled to the second resonant inductor Lr2. The first end of the second resonant inductor Lr2 is coupled to the second end of the second resonant capacitor Cr2, and the second end of the second resonant inductor Lr2 is coupled to the first end of the primary winding Np2 of the transformer circuit 400. The third resonant slot 360 includes a third resonant inductor Lr3 and a third resonant capacitor Cr3. The first end of the third resonant capacitor Cr3 is coupled to the third output node C, and the second end of the third resonant capacitor Cr3 is coupled to the third resonant inductor Lr3. The first end of the third resonant inductor Lr3 is coupled to the second end of the third resonant capacitor Cr3, and the second end of the third resonant inductor Lr3 is coupled to the first end of the primary winding Np3 of the transformer circuit 400. In this embodiment, the first resonant capacitor Cr1, the second resonant capacitor Cr2, and the third resonant capacitor Cr3 are coupled to the primary switching circuit 200 in a star connection.

[0021] In this embodiment, node J1 is located between the first resonant inductor Lr1 and the primary side of the first transformer T1; node J2 is located between the second resonant inductor Lr2 and the primary side of the second transformer T2; and node J3 is located between the third resonant inductor Lr3 and the primary side of the third transformer T3. The first end of the primary winding Np1 of the first transformer T1 is coupled to node J1, and the second end of the primary winding Np1 of the first transformer T1 is coupled to node J2. The first end of the primary winding Np2 of the second transformer T2 is coupled to node J2, and the second end of the primary winding Np2 of the second transformer T2 is coupled to node J3. The first end of the primary winding Np3 of the third transformer T3 is coupled to node J3, and the second end of the primary winding Np3 of the third transformer T3 is coupled to node J3. Therefore, in this embodiment, the primary winding Np1 of the first transformer T1, the primary winding Np2 of the second transformer T2, the primary winding Np3 of the third transformer T3, the first resonant inductor Lr1, the second resonant inductor Lr2, and the third resonant inductor Lr3 are coupled in a delta configuration.

[0022] Please refer to Figure 6, which is a schematic diagram of a control signal embodiment according to an embodiment of this application. In Figure 6, the horizontal axis represents time, and the vertical axis represents voltage level. Figure 6 includes control signals S1 to S6. Each control signal includes a high voltage level and a low voltage level. The phase difference between control signal S1 and control signal S2 is 180 degrees, and control signals S1 and S2 are complementary. The phase difference between control signal S3 and control signal S4 is 180 degrees, and control signals S3 and S4 are complementary. The phase difference between control signal S5 and control signal S6 is 180 degrees, and control signals S5 and S6 are complementary. The phase difference between control signal S1 and control signal S3 is 120 degrees. The phase difference between control signal S3 and control signal S5 is 120 degrees. The phase difference between control signal S2 and control signal S4 is 120 degrees. The phase difference between control signal S4 and control signal S6 is 120 degrees.

[0023] In one embodiment, a first dead time td1 exists between control signals S1 and S2, between control signals S3 and S4, and between control signals S5 and S6. Taking FIG7 as an example, the first dead time td1 exists between the falling edge of control signal S1 and the rising edge of control signal S2. This prevents switches on the same bridge arm (e.g., the first switching unit SW1 and the second switching unit SW2) from being simultaneously turned on. In one embodiment, the length of the first dead time td1 can be determined by the parasitic capacitance of a plurality of switching units in the primary-side switching circuit 200 and the secondary-side switching circuit 500, and the magnetizing inductance of a plurality of transformers. For example, when the magnetizing inductance is small, the switching unit can discharge quickly, therefore the length of the first dead time td1 can be relatively small. When the magnetizing inductance is large, the switching unit requires a longer discharge time. Therefore, the length of the first dead time td1 can be relatively large to ensure that the switching unit operates at zero voltage switching.

[0024] Please refer to Figure 8, which is a schematic diagram of a second embodiment of the control signals according to an embodiment of this application. In Figure 8, the horizontal axis represents time, and the vertical axis represents voltage level. Figure 8 includes control signals S7 to S12. Each control signal includes a high voltage level and a low voltage level. Control signal S7 and control signal S8 are complementary to each other. Control signal S9 and control signal S10 are complementary to each other. Control signal S11 and control signal S12 are complementary to each other. In this way, the simultaneous conduction of switches in the same rectifier unit (e.g., the seventh switch unit SW7 and the eighth switch unit SW8) can be avoided.

[0025] The operation of the resonant converter of this application will then be described with reference to Figures 2, 6, and 8. From time t0 to t1, the first switching unit SW1 is on, the second switching unit SW2 is off, the third switching unit SW3 is on, the fourth switching unit SW4 is off, the fifth switching unit SW5 is off, and the sixth switching unit SW6 is on. The first switching unit SW1 generates and transmits an input current I1 to the first resonant tank 310 based on the input voltage, and the first resonant tank 310 generates a resonant current based on the input current I1. The second switching unit SW2 generates and transmits an input current I2 to the second resonant tank 320 based on the input voltage, and the second resonant tank 320 generates a resonant current based on the input current I2. The primary side of the first transformer T1 generates a first input voltage and a first input current based on the resonant current of the first resonant tank 310, and the secondary side of the first transformer T1 generates a second output voltage and a second output current based on the first input voltage and the first input current. The operation of the second transformer T2 is similar to that of the first transformer T1, and therefore will not be described again here. Correspondingly, the seventh switch unit SW7 is closed, the eighth switch unit SW8 is open, the ninth switch unit SW9 is open, the tenth switch unit SW10 is closed, the eleventh switch unit SW11 is closed, and the twelfth switch unit SW12 is open. The ninth switch unit SW9 generates an output current based on the second output voltage on the secondary side of the second transformer T2. This output current is input to the output capacitor Co and the output resistor Ro to generate an output voltage.

[0026] From time point t1 to t2, the first switching unit SW1 is on, the second switching unit SW2 is off, the third switching unit SW3 is on, the fourth switching unit SW4 is off, the fifth switching unit SW5 is off, and the sixth switching unit SW6 is on. Correspondingly, the seventh switching unit SW7 is off, the eighth switching unit SW8 is off, the ninth switching unit SW9 is on, the tenth switching unit SW10 is off, the eleventh switching unit SW11 is off, and the twelfth switching unit SW12 is on. The ninth switching unit SW9 generates an output current based on the second output voltage on the secondary side of the second transformer T2. The output current is input to the output capacitor Co and the output resistor Ro to generate an output voltage.

[0027] From time point t2 to t3, the first switching unit SW1 is on, the second switching unit SW2 is off, the third switching unit SW3 is off, the fourth switching unit SW4 is on, the fifth switching unit SW5 is off, and the sixth switching unit SW6 is on. The first switching unit SW1 generates and transmits an input current I1 to the first resonant tank 310 based on the input voltage. Correspondingly, the seventh switching unit SW7 is on, the eighth switching unit SW8 is off, the ninth switching unit SW9 is on, the tenth switching unit SW10 is off, the eleventh switching unit SW11 is off, and the twelfth switching unit SW12 is on. The seventh switching unit SW7 generates an output current based on the second output voltage on the secondary side of the first transformer T1. The output current is input to the output capacitor Co and the output resistor Ro to generate an output voltage.

[0028] From time point t3 to t4, the first switching unit SW1 is on, the second switching unit SW2 is off, the third switching unit SW3 is off, the fourth switching unit SW4 is on, the fifth switching unit SW5 is off, and the sixth switching unit SW6 is on. Correspondingly, the seventh switching unit SW7 is on, the eighth switching unit SW8 is off, the ninth switching unit SW9 is off, the tenth switching unit SW10 is off, the eleventh switching unit SW11 is off, and the twelfth switching unit SW12 is on. The seventh switching unit SW7 generates an output current based on the second output voltage on the secondary side of the first transformer T1. The output current is input to the output capacitor Co and the output resistor Ro to generate an output voltage.

[0029] From time t4 to t5, the first switching unit SW1 is on, the second switching unit SW2 is off, the third switching unit SW3 is off, the fourth switching unit SW4 is on, the fifth switching unit SW5 is on, and the sixth switching unit SW6 is off. The first switching unit SW1 generates and transmits the input current I1 to the first resonant tank 310. The fifth switching unit SW5 generates and transmits the input current I3 to the third resonant tank 330 based on the input voltage. The primary side of the first transformer T1 generates a first input voltage and a first input current based on the resonant current of the first resonant tank 310, and the secondary side of the first transformer T1 generates a second output voltage and a second output current based on the first input voltage and the first input current. The operation of the third transformer T3 is similar to that of the first transformer T1, and therefore will not be described further here. Accordingly, the seventh switch unit SW7 is on, the eighth switch unit SW8 is off, the ninth switch unit SW9 is off, the tenth switch unit SW10 is on, the eleventh switch unit SW11 is off, and the twelfth switch unit SW12 is on. The seventh switch unit SW7 generates an output current based on the second output voltage on the secondary side of the first transformer T1. The output current is input to the output capacitor Co and the output resistor Ro to generate an output voltage.

[0030] From time point t5 to t6, the first switching unit SW1 is on, the second switching unit SW2 is off, the third switching unit SW3 is off, the fourth switching unit SW4 is on, the fifth switching unit SW5 is on, and the sixth switching unit SW6 is off. Correspondingly, the seventh switching unit SW7 is on, the eighth switching unit SW8 is off, the ninth switching unit SW9 is off, the tenth switching unit SW10 is on, the eleventh switching unit SW11 is off, and the twelfth switching unit SW12 is off. The seventh switching unit SW7 generates an output current based on the second output voltage on the secondary side of the first transformer T1. The output current is input to the output capacitor Co and the output resistor Ro to generate an output voltage.

[0031] From time t6 to t7, the first switching unit SW1 is closed, the second switching unit SW2 is open, the third switching unit SW3 is closed, the fourth switching unit SW4 is open, the fifth switching unit SW5 is open, and the sixth switching unit SW6 is closed. The fifth switching unit SW5 generates and transmits the input current I3 to the third resonant tank 330, and the third resonant tank 330 generates a resonant current based on the input current I3. The primary side of the third transformer T3 generates a first input voltage and a first input current based on the resonant current of the third resonant tank 330, and the secondary side of the third transformer T3 generates a second output voltage and a second output current based on the first input voltage and the first input current. Correspondingly, the seventh switching unit SW7 is open, the eighth switching unit SW8 is closed, the ninth switching unit SW9 is closed, the tenth switching unit SW10 is open, the eleventh switching unit SW11 is open, and the twelfth switching unit SW12 is closed. The eleventh switching unit SW11 generates an output current based on the second output voltage on the secondary side of the third transformer T3. The output current is input to the output capacitor Co and the output resistor Ro to generate an output voltage.

[0032] From time point t7 to t8, the first switching unit SW1 is closed, the second switching unit SW2 is open, the third switching unit SW3 is closed, the fourth switching unit SW4 is open, the fifth switching unit SW5 is open, and the sixth switching unit SW6 is closed. Correspondingly, the seventh switching unit SW7 is closed, the eighth switching unit SW8 is closed, the ninth switching unit SW9 is closed, the tenth switching unit SW10 is open, the eleventh switching unit SW11 is open, and the twelfth switching unit SW12 is closed. The eleventh switching unit SW11 generates an output current based on the second output voltage on the secondary side of the third transformer T3. The output current is input to the output capacitor Co and the output resistor Ro to generate an output voltage.

[0033] From time t8 to t9, the first switching unit SW1 is closed, the second switching unit SW2 is open, the third switching unit SW3 is open, the fourth switching unit SW4 is closed, the fifth switching unit SW5 is open, and the sixth switching unit SW6 is closed. The third switching unit SW3 generates and transmits an input current I2 to the second resonant tank 320, and the second resonant tank 320 generates a resonant current based on the input current I2. The fifth switching unit SW5 generates and transmits an input current I3 to the third resonant tank 330, and the third resonant tank 330 generates a resonant current based on the input current I3. The primary side of the second transformer T2 generates a first input voltage and a first input current based on the resonant current of the second resonant tank 320, and the secondary side of the second transformer T2 generates a second output voltage and a second output current based on the first input voltage and the first input current. The operation of the third transformer T3 is similar to that of the second transformer T2, and therefore will not be described further here. Accordingly, the seventh switch unit SW7 is closed, the eighth switch unit SW8 is open, the ninth switch unit SW9 is closed, the tenth switch unit SW10 is open, the eleventh switch unit SW11 is open, and the twelfth switch unit SW12 is closed. The eleventh switch unit SW11 generates an output current based on the second output voltage on the secondary side of the third transformer T3. The output current is input to the output capacitor Co and the output resistor Ro to generate an output voltage.

[0034] From time t9 to t10, the first switching unit SW1 is closed, the second switching unit SW2 is open, the third switching unit SW3 is open, the fourth switching unit SW4 is closed, the fifth switching unit SW5 is open, and the sixth switching unit SW6 is closed. Correspondingly, the seventh switching unit SW7 is closed, the eighth switching unit SW8 is open, the ninth switching unit SW9 is closed, the tenth switching unit SW10 is closed, the eleventh switching unit SW11 is open, and the twelfth switching unit SW12 is closed. The eleventh switching unit SW11 generates an output current based on the second voltage on the secondary side of the third transformer T3. The output current is input to the output capacitor Co and the output resistor Ro to generate an output voltage.

[0035] From time t10 to t11, the first switching unit SW1 is closed, the second switching unit SW2 is open, the third switching unit SW3 is open, the fourth switching unit SW4 is closed, the fifth switching unit SW5 is closed, and the sixth switching unit SW6 is open. The third switching unit SW3 generates and transmits the input current I2 to the second resonant tank 320. The primary side of the second transformer T2 generates a first input voltage and a first input current, and the secondary side of the second transformer T2 generates a second output voltage and a second output current based on the first input voltage and the first input current. Correspondingly, the seventh switching unit SW7 is closed, the eighth switching unit SW8 is open, the ninth switching unit SW9 is open, the tenth switching unit SW10 is closed, the eleventh switching unit SW11 is open, and the twelfth switching unit SW12 is closed. The ninth switching unit SW9 generates an output current based on the second output voltage of the secondary side of the second transformer T2, and the output current is input to the output capacitor Co and the output resistor Ro to generate the output voltage.

[0036] From time point t11 ​​to t12, the first switching unit SW1 is closed, the second switching unit SW2 is open, the third switching unit SW3 is open, the fourth switching unit SW4 is closed, the fifth switching unit SW5 is closed, and the sixth switching unit SW6 is open. Correspondingly, the seventh switching unit SW7 is closed, the eighth switching unit SW8 is open, the ninth switching unit SW9 is open, the tenth switching unit SW10 is closed, the eleventh switching unit SW11 is closed, and the twelfth switching unit SW12 is closed. The ninth switching unit SW9 generates an output current based on the second output voltage on the secondary side of the second transformer T2. The output current is input to the output capacitor Co and the output resistor Ro to generate an output voltage.

[0037] In one embodiment, under the same ZVS current conditions, the specifications of the full-bridge-full-bridge resonant converter and the specifications of the resonant converter of this application can be set as shown in Tables 1 and 2. Electrical specifications Full-bridge to full-bridge resonant converter The resonant converter of this application Input voltage 400V 400V Output voltage 49.58 V 49.47V Output Wattage 10 kW 10 kW Switching frequency 100 kHz 100 kHz Operating point (full load) At the resonant point At the resonant point capacitor of primary side switch 105 pF 105 pF Dead Time 50 ns 50 ns Circle ratio 16:2 14:1 Magnetizing inductor 157.34 µH 245.09 µH Resonant capacitor 0.38 µF 129.3 nF Resonant inductor 6 µH 6 µH Leakage 0.65 µH 0.41 µH Table 1

[0038] It should be noted that the turns ratio of the first transformer T1, the turns ratio of the second transformer T2, and the turns ratio of the third transformer T3 are all set to the turns ratios shown in Table 1. The first dead time td1 is set to the dead time shown in Table 1. The magnetizing inductors Lm1, Lm2, and Lm3 are all set to the magnetizing inductors shown in Table 1. The first resonant capacitor Cr1, the second resonant capacitor Cr2, and the third resonant capacitor Cr3 are all set to the resonant capacitors shown in Table 1. The first resonant inductor Lr1, the second resonant inductor Lr2, and the third resonant inductor Lr3 are all set to the resonant inductors shown in Table 1. Therefore, the embodiments of this application can reduce the number of primary winding coils compared to a full-bridge resonant converter. Core Specifications Full-bridge to full-bridge resonant converter The resonant converter of this application Cross-sectional area (Ae) of the center post of the magnetic core 174.04 mm2 174.04 mm2 Material KF9 KF9 Maximum magnetic flux density (hypothetical) 0.25T 0.25T Primary coil 0.1 * 500 shares 0.1 * 500 shares Secondary coil 0.6mm copper sheet 0.6mm copper sheet Circle ratio 16:2 14:1 air gap 0.38 mm 0.12 mm Table 2

[0039] It should be noted that the primary winding Np1 of the first transformer T1, the primary winding Np2 of the second transformer T2, and the primary winding Np3 of the third transformer T3 are all set as the primary windings shown in Table 2, and the secondary windings Ns1 of the first transformer T1, the secondary winding Ns2 of the second transformer T2, and the secondary winding Ns3 of the third transformer T3 are all set as the secondary windings shown in Table 2.

[0040] The performance of the full-bridge-full-bridge resonant converter and the resonant converter of this application are shown in Table 3. Performance parameters Full bridge - Full bridge Resonant converter This application Resonant converter Peak primary-side switching current (A) 14.13 16.6 Effective value of primary side switching current (A) 7.13 7.36 Effective value of primary transformer current (A) 10.09 12.02 Number of primary side switches 12 12 Peak secondary-side switching current (A) 105.71 107.41 RMS value of secondary-side switching current (A) 52.54 56.15 RMS value of secondary transformer current (A) 74.2 79.43 (parallel) Number of secondary side switches 12 12 Table 3

[0041] It should be noted that, in the embodiments in Table 3, the first switching unit SW1 to the sixth switching unit S6 of the resonant converter of this application are each connected in parallel with a switching unit. Therefore, the number of primary-side switches of the resonant converter of this application is the same as that of the full-bridge-full-bridge resonant converter, which is 12. The seventh switching unit SW7 to the twelfth switching unit S12 of the resonant converter of this application are each connected in parallel with a switching unit. Therefore, the number of secondary-side switches of the resonant converter of this application is the same as that of the full-bridge-full-bridge resonant converter, which is 12. As can be seen from Table 3, under the same number of primary-side switches and secondary-side switches, the current stress of the resonant converter of this application is similar to that of the full-bridge-full-bridge resonant converter, and therefore the copper loss is also similar. That is, this application has lower core loss.

[0042] The performance of the full-bridge-full-bridge resonant converter and the resonant converter of this application are shown in Table 4. Performance parameters Full bridge - Full bridge Resonant converter This application Resonant converter One-way connection method The whole bridge Examples of this application Secondary side connection method The whole bridge Star Output voltage Vo Vo Circle ratio Np Np*1.75 Operating frequency At the resonant point At the resonant point Maximum magnetic flux density Peak current (for calculating ZVS conditions) Magnetizing inductor Table 4

[0043] As can be seen from Table 4, the resonant converter of this application embodiment has a lower magnetic flux density than the full-bridge-full-bridge resonant converter. Therefore, under the same magnetic core, the magnetic core loss of the resonant converter of this application embodiment will be smaller.

[0044] Please refer to Figures 2 and 9. Figure 9 is a comparison diagram of the error of the three-phase current of the resonant converter and the full-bridge-full-bridge resonant converter according to the embodiment of this application, wherein the first current I1, the second current I2 and the third current I3 are the three-phase currents flowing into the resonant circuit (e.g., the resonant circuit 300 of this application).

[0045] The upper half of Figure 9 shows the current variations of the first current Ip1, the second current Ip2, and the third current Ip3 of the full-bridge-full-bridge resonant converter. The lower half of Figure 9 shows the current variations of the input currents I1, I2, and I3 of the resonant converter according to an embodiment of this application. The first current Ip1 is in phase with the input current I1. The second current Ip2 is in phase with the input current I2. The third current Ip3 is in phase with the input current I3. The left side of Figure 9 shows the current variations when the value of the second resonant inductor Lr2 is 1.1 times the value of the first resonant inductor Lr1 and the value of the third resonant inductor Lr3 is 0.9 times the value of the first resonant inductor Lr1. The middle part of Figure 9 shows the current variations when the value of the second resonant capacitor Cr2 is 1.1 times the value of the first resonant capacitor Cr1 and the value of the third resonant capacitor Cr3 is 0.9 times the value of the first resonant capacitor Cr1. The right side of Figure 9 shows the current changes when the value of the second resonant inductor Lr2 is 1.1 times the value of the first resonant inductor Lr1, the value of the third resonant inductor Lr3 is 0.9 times the value of the first resonant inductor Lr1, and the value of the second resonant capacitor Cr2 is 1.1 times the value of the first resonant capacitor Cr1, and the value of the third resonant capacitor Cr3 is 0.9 times the value of the first resonant capacitor Cr1. As can be seen from the figure, the peak differences of the input currents I1, I2, and I3 under different component errors in this embodiment are less than the peak differences of the first current Ip1, second current Ip2, and third current Ip3 of the full-bridge-full-bridge resonant converter under different component errors. That is, the current difference caused by component errors in the resonant converter of this embodiment is less than the current difference caused by component errors in the full-bridge-full-bridge resonant converter. Therefore, the resonant converter of this application has a higher tolerance for current errors caused by component errors.

[0046] The performance of the full-bridge-full-bridge resonant converter and the resonant converter of this application are shown in Table 5. Resonant inductor current Full bridge - Full bridge Resonant converter This application Resonant converter Components without error ILr1 14.12 A 20.81 A ILr2 14.12 A 20.81 A ILr3 14.12 A 20.81 A Resonant inductor error ILr1 14.74 A (+4.39%) 20.90 A (+0.43%) ILr2 12.61 A (-10.69%) 21.58 A (+3.7%) ILr3 15.03 A (+6.45%) 20.02 A (-3.79%) Resonant capacitor error ILr1 15.01 A (+6.3%) 20.86 A (+0.24%) ILr2 11.98 A (-15.15%) 21.53 A (+3.46%) ILr3 15.45 A (+9.41%) 20.19 A (-2.97%) Resonant inductor and resonant capacitor errors ILr1 15.72 A (+11.33%) 20.91 A (+0.48%) ILr2 10.54 A (-25.35%) 22.35 A (+7.4%) ILr3 16.46 A (+16.57%) 19.42 A (-6.67%) Table 5

[0047] In Table 5, ILr1, ILr2, and ILr3 represent the currents of the first resonant inductor Lr1, the second resonant inductor Lr2, and the third resonant inductor Lr3, respectively. As can be seen from Table 5, the change in current of the resonant inductor in the resonant converter of this embodiment is significantly smaller than the change in current of the resonant inductor in the full-bridge-full-bridge resonant converter when component errors exist. The current difference caused by component errors in the resonant converter of this embodiment is smaller than the current difference caused by component errors in the full-bridge-full-bridge resonant converter.

[0048] In the embodiments of this application, the resonant inductors and transformers of the resonant converter can be individually implemented with discrete magnetic cores or by a single integrated magnetic core module.

[0049] Please refer to Figures 10A to 10C. Figure 10A is a perspective view of an integrated magnetic core module according to an embodiment of this application. Figure 10B is another perspective view of an integrated magnetic core module according to an embodiment of this application. Figure 10C is a cross-sectional view of an integrated magnetic core module according to an embodiment of this application. The integrated magnetic core module 700 includes a top cover 710, an integrated transformer 730, and an integrated resonant inductor unit 720. The integrated resonant inductor unit 720 is disposed between the top cover 710 and the integrated transformer 730.

[0050] The integrated transformer 730 includes a lower cover 731, a plurality of transformer core columns 732, and a common transformer column 733. The plurality of transformer core columns 732 and the common transformer column 733 are disposed on the lower cover 731. The plurality of transformer core columns 732 are arranged around the common transformer column 733. The distance between the plurality of transformer core columns 732 and the common transformer column 733 is the same. By ensuring that the distance between the plurality of transformer core columns 732 and the common transformer column 733 is the same, magnetic flux balance between phases can be effectively maintained. In one embodiment, the common transformer column 733 is disposed at the center of the lower cover 731.

[0051] Each transformer core column 732 includes two core column units 7321. The two core column units 7321 are stacked on top of each other. An air gap 7322 is formed between the two core column units 7321. The air gap 7322 of each transformer core column 732 is the same size.

[0052] The cross-sectional area of ​​the plurality of transformer core columns 732 is the same as the cross-sectional area of ​​the common transformer column 733. Since the magnetic flux flowing through the plurality of transformer core columns 732 is the same as the magnetic flux flowing through the common transformer column 733, the cross-sectional area of ​​the common transformer column 733 must be at least the same as the cross-sectional area of ​​the plurality of transformer core columns 732 to avoid magnetic flux saturation of the plurality of transformer core columns 732.

[0053] Referring to Figure 10D, each transformer core 732 of the integrated magnetic core module 700 is provided with a primary winding 7341 and a secondary winding 7342. The primary winding 7341 is, for example, the aforementioned primary winding Np1, primary winding Np2, or primary winding Np3. The secondary winding 7342 is, for example, the aforementioned secondary winding Ns1, secondary winding Ns2, or secondary winding Ns1. The winding direction of the primary winding 7341 and the secondary winding 7342 is clockwise or counterclockwise. Therefore, the aforementioned plurality of transformers (first transformer T1, second transformer T2, and third transformer T3) can be individually implemented by a set of transformer cores 732, primary windings 7341, and secondary windings 7342. The positions of the plurality of transformers in the integrated transformer 730 can be adjusted as needed. Taking Figure 10A as an example, with the transformer core 732 as the reference, the transformers can be arranged in the following order: first transformer T1, second transformer T2 and third transformer T3 in a clockwise direction, or in the following order: first transformer T1, second transformer T2 and third transformer T3 in a counterclockwise direction.

[0054] In one embodiment, the primary winding 7341 is, for example, wound with stranded wire. Since the air gap 7322 is located at the center of the transformer core 732, the use of stranded wire effectively reduces AC losses caused by the air gap 7322. In another embodiment, the secondary winding 7342 is, for example, wound with copper sheet. Because the current in the secondary winding 7342 is relatively large, copper sheet capable of carrying a large current is selected.

[0055] The integrated resonant inductor unit 720 includes an intermediate cover plate 721, a plurality of inductor cores 722, and a common inductor post 723. The intermediate cover plate 721 is located on the plurality of transformer cores 732 and the common transformer post 733 and is located away from the lower cover 731. The plurality of inductor cores 722 and the common inductor post 723 are disposed on the intermediate cover plate 721. The plurality of inductor cores 722 are arranged around the common inductor post 723. The distance between the plurality of inductor cores 722 and the common inductor post 723 is the same. By making the distance between the plurality of inductor cores 722 and the common inductor post 723 the same, the magnetic flux balance between each phase can be effectively maintained. In one embodiment, the common inductor post 723 is disposed at the center of the intermediate cover plate 721. In one embodiment, the vertical projection of the inductor common post 723 onto the intermediate cover plate 721 and the vertical projection of the transformer common post 733 onto the intermediate cover plate 721 may at least partially overlap or not overlap.

[0056] Each inductor core 722 includes two core units 7221. The two core units 7221 are stacked on top of each other. An air gap 7222 is formed between the two core units 7221. The air gap 7222 of each inductor core 722 is the same size. In one embodiment, the air gap 7222 of the inductor core 722 is larger than the air gap 7322 of the transformer core 7322. The size of the air gap 7222 is, for example, at least three times the size of the air gap 7322.

[0057] The cross-sectional area of ​​the plurality of inductor cores 722 is the same as the cross-sectional area of ​​the common inductor core 723. Since the magnetic flux flowing through the plurality of inductor cores 722 is the same as the magnetic flux flowing through the common inductor core 723, the cross-sectional area of ​​the common inductor core 723 must be at least the same as the cross-sectional area of ​​the plurality of inductor cores 722 to avoid magnetic flux saturation of the plurality of inductor cores 722. In one embodiment, the cross-sectional area of ​​the transformer core 732 is larger than the cross-sectional area of ​​the inductor core 722. For example, the cross-sectional area of ​​the transformer core 732 is at least twice the cross-sectional area of ​​the inductor core 722.

[0058] As shown in Figure 10D, each inductor core 722 is provided with an inductor coil 724. The winding direction of the inductor coil 724 is either clockwise or counterclockwise. Therefore, the aforementioned plurality of resonant inductors (first resonant inductor Lr1, second resonant inductor Lr2, and third resonant inductor Lr3) can be individually implemented by a set of inductor cores 722 and inductor coils 724. The positions of the plurality of resonant inductors in the integrated resonant inductor unit 720 can be adjusted as needed. Taking Figure 10A as an example, based on the plurality of inductor cores 722, the order can be first resonant inductor Lr1, second resonant inductor Lr2, and third resonant inductor Lr3 in a clockwise direction or in a counterclockwise direction. Furthermore, the positions of the plurality of resonant inductors in the integrated resonant inductor unit 720 are not limited by the positions of the plurality of transformers in the integrated transformer 730. For example, the first resonant inductor Lr1 can be positioned above the second transformer T2, rather than above the first transformer T1.

[0059] In one embodiment, the inductor coil 724 is, for example, made of stranded wire. Since the air gap 7222 is located at the center of the inductor core 722, the AC loss caused by the air gap 7222 can be effectively reduced by using stranded wire.

[0060] In one embodiment, the shapes of the upper cover 710, the middle cover 721, and the lower cover 731 may correspond to each other. The shapes of the upper cover 710, the middle cover 721, and the lower cover 731 may be circular, square, or triangular, and this application is not limited thereto.

[0061] Please refer to Figures 11 and 12. Figure 11 is a perspective view of an integrated magnetic core module according to an embodiment of this application. Figure 12 is a cross-sectional view of an integrated magnetic core module according to an embodiment of this application. The integrated magnetic core module 800 includes an upper cover 810, a lower cover 820, a plurality of core posts 830, and a common post 840. The plurality of core posts 830 and the common post 840 are disposed between the upper cover 810 and the lower cover 820. Please also refer to Figure 10. The plurality of core posts 830 can be implemented by a plurality of transformer core posts 732, and the common post 840 can be implemented by a transformer common post 733, therefore, it will not be described in detail here.

[0062] Each core post 830 has a primary-side coil 851 and a secondary-side coil 852. The winding direction of the primary-side coil 851 and the secondary-side coil 852 is clockwise or counterclockwise. There is a distance between the primary-side coil 851 and the secondary-side coil 852. Therefore, the aforementioned plurality of transformers (first transformer T1, second transformer T2, and third transformer T3) can be individually implemented by a set of core posts 830, primary-side coils 851, and secondary-side coils 852. In this embodiment, the plurality of resonant inductors are implemented by the leakage inductance of the plurality of transformers. The magnitude of the leakage inductance is proportional to the distance between the primary-side coils 851 and the secondary-side coils 852. For example, the first resonant inductor Lr1 is implemented by the leakage inductance of the first transformer T1. In this embodiment, by implementing the resonant inductance with the leakage inductance of the transformer, the volume required for the resonant converter can be significantly reduced. In this embodiment, the primary-side coil 851 must be wound in a concentrated manner. In other words, the primary coil 851 is not implemented using a plurality of discrete coils.

[0063] In this embodiment, the secondary coil 852 can be implemented as a single coil or a plurality of discrete coils. In one embodiment, the secondary coil 852 includes a first secondary coil unit 8521 and a second secondary coil unit 8522, with the primary coil 851 located between the first secondary coil unit 8521 and the second secondary coil unit 8522, and the primary coil 851 having the distance between it and the first secondary coil unit 8521 and the second secondary coil unit 8522.

[0064] In one embodiment, the primary coil 851 is, for example, made of stranded wire. In another embodiment, the secondary coil 852 is, for example, made of copper sheet.

[0065] In summary, since the resonant converter of this application can reduce the magnetic flux density through the configuration of multiple resonant slots, thereby reducing the magnetic core loss, and has a good current balancing effect when there are characteristic errors in the components, it can achieve the effect of balancing the current of each phase without increasing the product size and production cost of the power supply circuit.

[0066] 1: Power supply circuit 10, 11, 12, 13: Resonant converters 20: Control Circuit 100: Input Circuit 200: Primary side switching circuit 210: First bridge arm 220: Second bridge arm 230: Third bridge arm 300, 301, 303: Resonant circuits 310, 340: First resonant slot 320, 350: Second resonant slot 330°, 360°: Third resonant slot 400: Transformer Circuit 500: Secondary side switching circuit 510: First Rectifier Unit 520: Second rectifier unit 530: Third Rectifier Unit 600: Output Circuit 700: Integrated magnetic core module 710: Top Cover 720: Integrated resonant inductor unit 721: Intermediate cover plate 722: Inductor Core 7221: Core Column Unit 7222: Air gap 723: Common inductor post 724: Inductor coil 730: Integrated Transformer 731: Bottom Cover 732: Transformer Core 7321: Core Column Unit 7322: Air gap 733: Common column for transformers 7341: Primary coil 7342: Secondary coil 800: Integrated magnetic core module 810: Top Cover 820: Bottom Cover 830: Core Pillar 840: Shared Column 851: Primary coil 852: Secondary coil 8521: First and Secondary Side Coil Unit 8522: Secondary side coil unit A: First output node B: Second output node C: Third output node Cin: Input capacitance Cr1: First resonant capacitor Cr2: Second resonant capacitor Cr3: Third resonant capacitor Co: Output capacitor D: First input node E: Second input node F: Third input node G1, G2, G3, H, J1, J2, J3, K: Nodes I1, I2, I3: Input current Ip1: First current Ip2: Second current Ip3: Third Current Lr1: First resonant inductor Lr2: Second resonant inductor Lr3: Third resonant inductor Lm1, Lm2, Lm3: Magnetizing inductors Np1, Np2, Np3: Primary winding Ns1, Ns2, Ns3: Secondary windings Ro: Output resistance S1~S12: Control signals SW1: First Switching Unit SW2: Second Switching Unit SW3: Third Switching Unit SW4: Fourth Switching Unit SW5: Fifth Switching Unit SW6: Sixth Switching Unit SW7: Seventh Switching Unit SW8: Eighth Switching Unit SW9: Ninth Switching Unit SW10: Tenth Switching Unit SW11: Eleventh Switching Unit SW12: Twelfth Switch Unit T1: First Transformer T2: Second Transformer T3: Third Transformer t0~t12: Time points td1: First Dead Zone Time Vs: Voltage source

Claims

1. A resonant converter, comprising: An input circuit provides an input voltage; A primary-side switching circuit coupled to the input circuit includes a first output node, a second output node, and a third output node; a resonant circuit including a plurality of resonant slots, each of the plurality of resonant slots including a resonant capacitor and a resonant inductor connected in series, the plurality of resonant slots being star-connected to the first output node, the second output node, and the third output node; a transformer circuit having a plurality of transformers, each of the plurality of transformers including a primary-side winding and a secondary-side winding, the primary-side windings being delta-connected to the plurality of resonant slots, the transformer circuit including a first transformer, a second transformer, and a third transformer; a secondary-side switching circuit coupled to the transformer circuit includes a first input node, a second input node, and a third input node, the first input node, the second input node, and the third input node being star-connected to the secondary-side windings of the transformer circuit; The circuit includes an output circuit coupled to the secondary-side switching circuit and generating an output voltage. The resonant circuit comprises: a first resonant slot, including a first resonant inductor and a first resonant capacitor, the first resonant inductor being coupled to the first output node and the first resonant capacitor, and the first resonant capacitor being coupled to the first end of the primary winding of the first transformer; a second resonant slot, including a second resonant inductor and a second resonant capacitor, the second resonant inductor being coupled to the second output node and the second resonant capacitor, and the second resonant capacitor being coupled to the second end of the primary winding of the first transformer and the first end of the primary winding of the second transformer; and a third resonant slot, including a third resonant inductor and a third resonant capacitor, the third resonant inductor being coupled to the third output node and the third resonant capacitor, and the third resonant capacitor being coupled to the second end of the primary winding of the second transformer and the first end of the primary winding of the third transformer. The first end of the secondary winding is coupled; wherein the resonant inductors and transformers are integrated into an integrated magnetic core module, the integrated magnetic core module including a top cover, an integrated transformer and an integrated resonant inductor unit, the integrated resonant inductor unit being disposed between the top cover and the integrated transformer; wherein the integrated transformer includes a bottom cover, a plurality of transformer core columns and a transformer common column, the plurality of transformer core columns and the transformer common column being disposed on the bottom cover, the transformer common column being used to provide a magnetic field path corresponding to the plurality of transformers; wherein the integrated resonant inductor unit includes an intermediate cover plate, a plurality of inductor core columns and a common inductor column, the plurality of inductor core columns and the common inductor column being disposed on the intermediate cover plate, the common inductor column being used to provide a magnetic field path corresponding to the plurality of resonant inductors; wherein the air gap of the plurality of inductor core columns is larger than the air gap of the plurality of transformer core columns.

2. The resonant converter as claimed in claim 1, wherein, The primary-side switching circuit includes: a first bridge arm comprising a first switching unit and a second switching unit connected in series, wherein the first output node is located between the first switching unit and the second switching unit; a second bridge arm comprising a third switching unit and a fourth switching unit connected in series, wherein the second output node is located between the third switching unit and the fourth switching unit; and a third bridge arm comprising a fifth switching unit and a sixth switching unit connected in series, wherein the third output node is located between the fifth switching unit and the sixth switching unit.

3. The resonant converter as described in claim 2, wherein, The control signals of the first and second switching units are complementary to each other, the control signals of the third and fourth switching units are complementary to each other, and the control signals of the fifth and sixth switching units are complementary to each other.

4. The resonant converter as described in claim 3, wherein, There is a first dead time between the control signal of the first switch unit and the control signal of the second switch unit, between the control signal of the third switch unit and the control signal of the fourth switch unit, and between the control signal of the fifth switch unit and the control signal of the sixth switch unit.

5. The resonant converter as described in claim 2, wherein, The control signal of the first switching unit is 120 degrees out of phase with the control signal of the third switching unit, and the control signal of the third switching unit is 120 degrees out of phase with the control signal of the fifth switching unit.

6. The resonant converter as claimed in claim 1, wherein the secondary winding of the first transformer is coupled to the first input node of the secondary switching circuit; the secondary winding of the second transformer is coupled to the second input node of the secondary switching circuit; and the secondary winding of the third transformer is coupled to the third input node of the secondary switching circuit.

7. The resonant converter as claimed in claim 1, wherein, The first resonant capacitor is coupled between the first resonant inductor and the second terminal of the primary winding of the third transformer.

8. The resonant converter as claimed in claim 1, wherein, The first resonant inductor is coupled between the first output node and the second terminal of the primary winding of the third transformer.

9. The resonant converter as claimed in claim 1, wherein, The first resonant inductor is coupled between the first output node, the second end of the primary winding of the third transformer, and the first resonant capacitor.

10. The resonant converter as claimed in claim 1, wherein, The secondary-side switching circuit includes: a first rectifier unit comprising a seventh switch unit and an eighth switch unit connected in series, with the first input node located between the seventh switch unit and the eighth switch unit; a second rectifier unit comprising a ninth switch unit and a tenth switch unit connected in series, with the second input node located between the ninth switch unit and the tenth switch unit; and a third rectifier unit comprising an eleventh switch unit and a twelfth switch unit connected in series, with the third input node located between the eleventh switch unit and the twelfth switch unit.

11. The resonant converter as claimed in claim 1, wherein, A plurality of transformer core columns are arranged around a common transformer column, the cross-sectional area of ​​the plurality of transformer core columns is the same as that of the common transformer column, and the distance between the plurality of transformer core columns and the common transformer column is the same.

12. The resonant converter as claimed in claim 11, wherein, A plurality of inductor cores are arranged around a common inductor post, the cross-sectional area of ​​the plurality of inductor cores is the same as that of the common inductor post, and the distance between the plurality of inductor cores and the common inductor post is the same.

13. The resonant converter as claimed in claim 12, wherein, The cross-sectional area of ​​a plurality of the transformer cores is greater than the cross-sectional area of ​​a plurality of the inductor cores.

14. The resonant converter as claimed in claim 1, wherein, The resonant inductor near the air gap of the inductor core is made of a stranded wire, and the transformer near the air gap of the transformer core is made of the same stranded wire.

15. The resonant converter as claimed in claim 1, wherein, The primary winding of the transformer is made of a stranded wire, and the secondary winding is made of a copper sheet.

16. A resonant converter, comprising: An input circuit provides an input voltage; A primary-side switching circuit coupled to the input circuit includes a first output node, a second output node, and a third output node; a resonant circuit including a plurality of resonant slots, each of the plurality of resonant slots including a resonant capacitor and a resonant inductor connected in series, the plurality of resonant slots being star-connected to the first output node, the second output node, and the third output node; a transformer circuit having a plurality of transformers, each of the plurality of transformers including a primary-side winding and a secondary-side winding, the primary-side windings being delta-connected to the plurality of resonant slots, the transformer circuit including a first transformer, a second transformer, and a third transformer; a secondary-side switching circuit coupled to the transformer circuit includes a first input node, a second input node, and a third input node, the first input node, the second input node, and the third input node being star-connected to the secondary-side windings of the transformer circuit; The circuit includes an output circuit coupled to the secondary-side switching circuit and generating an output voltage. The resonant circuit comprises: a first resonant slot, including a first resonant inductor and a first resonant capacitor, one end of the first resonant capacitor being coupled to the first output node, and the other end of the first resonant capacitor being coupled to one end of the first resonant inductor and the second end of the primary winding of the third transformer; a second resonant slot, including a second resonant inductor and a second resonant capacitor, the second resonant capacitor being coupled to the second output node and one end of the second resonant inductor, and the other end of the second resonant inductor being coupled to the second end of the primary winding of the first transformer and the first end of the primary winding of the second transformer; and a third resonant slot, including a third resonant inductor and a third resonant capacitor, the third resonant capacitor being coupled to the third output node and one end of the third resonant inductor, and the other end of the third resonant inductor being coupled to the second output node and one end of the third resonant inductor. The second end of the primary winding of the second transformer is coupled to the first end of the primary winding of the third transformer; wherein, the resonant inductors and the transformers are integrated into an integrated magnetic core module, the integrated magnetic core module including a top cover, an integrated transformer, and an integrated resonant inductor unit, the integrated resonant inductor unit being disposed between the top cover and the integrated transformer; wherein, the integrated transformer includes a bottom cover, a plurality of transformer core columns, and a transformer common column, the plurality of which... The transformer core column and the common column of the transformer are disposed on the lower cover. The common column of the transformer is used to provide magnetic field paths corresponding to the plurality of transformers. The integrated resonant inductor unit includes an intermediate cover plate, a plurality of inductor core columns and a common column of the inductor. The plurality of inductor core columns and the common column of the inductor are disposed on the intermediate cover plate. The common column of the inductor is used to provide magnetic field paths corresponding to the plurality of resonant inductors. The air gap of the plurality of inductor core columns is larger than the air gap of the plurality of transformer core columns.

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