A resonant converter circuit and a resonant converter

Abstract

The embodiment of the present application discloses a resonant converter circuit and a resonant converter, the resonant converter circuit comprises a first resonant conversion circuit, a second resonant conversion circuit, a first coupling inductor and a control unit, the first resonant conversion circuit comprises a first switch module and a first resonant cavity module, the first switch module is connected with the first resonant cavity module, the second resonant conversion circuit comprises a second switch module and a second resonant cavity module, the second switch module is connected with the second resonant cavity module, the control unit is connected with the first switch module and the second switch module respectively, the control unit is used for outputting a control signal to control the switching state of the first switch module and the second switch module, the first coupling inductor is connected with the first resonant cavity module and the second resonant cavity module respectively, and the first coupling inductor is used for adjusting the current in the first resonant cavity module and the second resonant cavity module. Through the above mode, the current sharing control can be realized through a relatively simple hardware structure, and the cost is relatively low.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power electronics, in particular to a resonant converter circuit and a resonant converter. BACKGROUND

[0002] The phase-shifted full-bridge resonant converter has the advantages of wide input and output voltage range, large current output, etc., and is therefore used in the fields of vehicle-mounted power supply, server power supply, communication power supply, etc.

[0003] In high-power application scenarios, output parallel technology is often used. Due to slight differences in manufacturing process and mode of components, inconsistency between components is caused, and meanwhile, due to complex parasitic parameters of transformers and inductors, dispersion between magnetic components is caused. Therefore, parameters in the phase-shifted full-bridge parallel circuit must be different. This will cause different current stresses borne by circuits in the resonant cavity in the full-bridge parallel circuit. In severe cases, it can even cause damage to power devices and the circuit cannot work normally.

[0004] The existing processing scheme is to change the control signals of each switch tube in the phase-shifted full-bridge resonant converter to realize balanced control of the current in the resonant cavity. However, this method needs to be controlled by software, and the control is relatively complex, the implementation is difficult, and the cost is high. SUMMARY

[0005] The technical problem solved by the embodiments of the present application is to provide a resonant converter circuit and a resonant converter, which can realize current sharing control through a relatively simple hardware structure and have a low cost.

[0006] To achieve the above object, in a first aspect, the present application provides a resonant converter circuit, comprising:

[0007] a first resonant conversion circuit, a second resonant conversion circuit, a first coupled inductor, and a control unit;

[0008] The first resonant conversion circuit comprises a first switch module and a first resonant cavity module, and the first switch module is connected with the first resonant cavity module.

[0009] The second resonant conversion circuit comprises a second switch module and a second resonant cavity module, and the second switch module is connected with the second resonant cavity module.

[0010] The control unit is connected with the first switch module and the second switch module respectively, and is used to output a control signal to control the switching state of the first switch module and the second switch module.

[0011] The first coupling inductor is connected with the first resonant cavity module and the second resonant cavity module respectively, and is used for adjusting current in the first resonant cavity module and the second resonant cavity module.

[0012] In an optional mode, the first coupling inductor comprises a first winding and a second winding, the first winding is connected with the first resonant cavity module, and the second winding is connected with the second resonant cavity.

[0013] In an optional mode, the first switch module comprises a first bridge arm unit and a second bridge arm unit, the first bridge arm unit and the second bridge arm unit are connected in parallel;

[0014] The first resonant cavity module comprises a first resonant inductor and a first transformer;

[0015] A same-named end of the first resonant inductor is connected with the first bridge arm unit, a same-named end of the first resonant inductor is connected with a same-named end of the first winding, a same-named end of a primary winding of the first transformer is connected with an opposite-named end of the first winding, and an opposite-named end of the primary winding of the first transformer is connected with the second bridge arm unit.

[0016] In an optional mode, the first bridge arm unit comprises a first switch tube and a second switch tube connected in series in the same direction, and the second bridge arm unit comprises a third switch tube and a fourth switch tube;

[0017] A second end of the first switch tube is connected with a second end of the third switch tube, and a first end of the second switch tube is connected with a first end of the fourth switch tube;

[0018] A connection point between a first end of the first switch tube and a second end of the second switch tube is connected with a first end of the first resonant inductor, and a connection point between a first end of the third switch tube and a second end of the fourth switch tube is connected with an opposite-named end of the primary winding of the first transformer;

[0019] Control ends of the first switch tube, the second switch tube, the third switch tube and the fourth switch tube are connected with the control unit.

[0020] In an optional mode, the second switch module comprises a third bridge arm unit and a fourth bridge arm unit, the third bridge arm unit and the fourth bridge arm unit are connected in parallel;

[0021] The second resonant cavity module comprises a second resonant inductor and a second transformer;

[0022] The first end of the second resonant inductor is connected with the third bridge arm unit, the second end of the first resonant inductor is connected with the opposite-phase end of the first winding, the same-phase end of the primary winding of the second transformer is connected with the same-phase end of the first winding, and the opposite-phase end of the primary winding of the second transformer is connected with the fourth bridge arm unit.

[0023] In an optional mode, the third bridge arm unit comprises a fifth switch tube and a sixth switch tube connected in series in the same direction, and the second bridge arm unit comprises a seventh switch tube and an eighth switch tube;

[0024] The second end of the fifth switch tube is connected with the second end of the seventh switch tube, and the first end of the sixth switch tube is connected with the first end of the fourth switch tube;

[0025] The connection point between the first end of the fifth switch tube and the second end of the sixth switch tube is connected with the first end of the second resonant inductor, and the connection point between the first end of the seventh switch tube and the second end of the eighth switch tube is connected with the opposite-phase end of the primary winding of the second transformer;

[0026] The control end of the fifth switch tube, the control end of the sixth switch tube, the control end of the seventh switch tube, and the control end of the eighth switch tube are all connected with the control unit.

[0027] In an optional mode, the first switch module further comprises a first filter capacitor, and the second switch module further comprises a second filter capacitor;

[0028] The first filter capacitor is connected in parallel with the first bridge arm unit, and the second filter capacitor is connected in parallel with the second bridge arm unit.

[0029] In an optional mode, the resonant converter circuit further comprises a third resonant conversion circuit and a second coupling inductor;

[0030] The third resonant conversion circuit comprises:

[0031] A third switch module comprising a fifth bridge arm unit and a sixth bridge arm unit, the fifth bridge arm unit and the sixth bridge arm unit are connected in parallel;

[0032] A third resonant cavity module connected with the fifth bridge arm unit and the sixth bridge arm unit respectively;

[0033] The second coupling inductor is connected with the second resonant cavity module and the third resonant cavity module respectively.

[0034] In an optional mode, the second coupling inductor comprises a third winding and a fourth winding;

[0035] The same name end of the third winding is connected with the first coupling inductor, and the opposite name end of the third winding is connected with the second resonant cavity module.

[0036] The same name end and the opposite name end of the fourth winding are both connected with the third resonant cavity module.

[0037] In a second aspect, the embodiment of the present application further provides a resonant converter, which comprises a rectifying module and a resonant converter circuit as described above, and the resonant converter circuit is connected with the rectifying module.

[0038] The resonant converter circuit is used for voltage conversion on an input power supply.

[0039] The rectifying module is used for rectifying the input power supply after voltage conversion, so as to provide a power supply voltage for a load.

[0040] The embodiment of the present application has the following beneficial effects: the resonant converter circuit provided by the present application comprises a first resonant conversion circuit, a second resonant conversion circuit, a first coupling inductor and a control unit, the first resonant conversion circuit comprises a first switch module and a first resonant cavity module, the second resonant conversion circuit comprises a second switch module and a second resonant cavity module, wherein the first switch module is connected with the first resonant cavity module, the second switch module is connected with the second resonant cavity module, the control unit is connected with the first switch module and the second switch module respectively, and the first coupling inductor is connected with the first resonant cavity module and the second resonant cavity module respectively. Therefore, since the first coupling inductor is arranged between the first resonant cavity module and the second resonant cavity module, when the current difference of the first resonant cavity module or the second resonant cavity module changes, the first coupling inductor can generate an induced electromotive force to inhibit the change, so that the current balancing effect is achieved, that is, the current balancing control is realized by adding the first coupling inductor, which is a relatively simple hardware structure, and the required cost is low. BRIEF DESCRIPTION OF DRAWINGS

[0041] One or more embodiments are illustrated by way of example in the figures that are part of this disclosure and which are illustrative, but not restrictive, of the embodiments, wherein elements having the same reference numbers designate corresponding elements and wherein the notation “some” or “one or more” or “one or more of the” preceding a reference numeral or numerical designation is used herein to indicate an optional component or implementation that is not required, but which embodiment can use in one or more embodiments.

[0042] Figure 1 A structural schematic diagram of a resonant converter provided by the embodiment of the present application;

[0043] Figure 2 A structural schematic diagram of a resonant converter provided by the embodiment of the present application;

[0044] Figure 3 A circuit structural schematic diagram of a resonant converter circuit provided by the embodiment of the present application;

[0045] Figure 4 A waveform diagram of the PWM signal output by the control unit provided in an embodiment of the present invention;

[0046] Figure 5 A schematic diagram of the circuit structure of a resonant converter circuit provided in another embodiment of the present invention;

[0047] Figure 6 A schematic diagram of the circuit structure of a resonant converter circuit provided in another embodiment of the present invention;

[0048] Figure 7 This is a schematic diagram of the resonant converter circuit provided in another embodiment of the present invention;

[0049] Figure 8 A schematic diagram of the circuit structure of a resonant converter circuit provided in another embodiment of the present invention. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] Please refer to Figure 1 , Figure 1 A schematic diagram of the resonant converter provided in an embodiment of the present invention is shown below. Figure 1 As shown, the resonant converter 1000 includes a resonant converter circuit 100 and a rectifier circuit 200. The input terminal of the resonant converter circuit 100 is connected to an external power supply 300, the output terminal of the resonant converter circuit 100 is connected to the input terminal of the rectifier circuit 200, and the output terminal of the rectifier circuit 200 is connected to a load 400.

[0052] Specifically, when an external power supply 300 is input to the resonant converter 1000, the resonant converter circuit 100 in the resonant converter 1000 can adjust the external power supply 300 according to the switching state of each switch in the circuit, that is, perform voltage conversion, and input the external power supply 300 after voltage conversion to the rectifier circuit 200. The rectifier circuit 200 can be a full-bridge rectifier circuit or a half-bridge rectifier circuit, etc. The rectified external power supply 300 can then be used to provide power supply voltage for the actual external load. Therefore, the resonant converter 1000 can be applied to fields such as vehicle power supply, server power supply or communication power supply.

[0053] like Figure 2As shown, the resonant converter circuit 100 comprises a first resonant conversion circuit 10, a second resonant conversion circuit 20, a first coupling inductor 30 and a control unit 40, the first resonant conversion circuit 10 comprises a first switch module 11 and a first resonant cavity module 12, and the second resonant conversion circuit 20 comprises a second switch module 21 and a second resonant cavity module 22.

[0054] The first switch module 11 is connected with the first resonant cavity module 12, the second switch module 21 is connected with the second resonant cavity module 22, the control unit 40 is connected with the first switch module 11 and the second switch module 21 respectively, and the first coupling inductor 30 is connected with the first resonant cavity module 12 and the second resonant cavity module 22 respectively.

[0055] Specifically, the control unit 40 can output a first control signal to control the switching state of each switch tube in the first switch module 11, and the control unit 40 can output a second control signal to control the switching state of each switch tube in the second switch module 21, so as to realize the adjustment of the input power connected with the resonant converter circuit 100, wherein the first control signal and the second control signal can be the same signal or different signals, for example, the duty cycles of the first control signal and the second control signal are the same, but the amplitudes corresponding to the high level in the signals are different, so as to realize the driving of different switch tubes.

[0056] The first coupling inductor 30 is used to adjust the current in the first resonant cavity module 12 or the current in the second resonant cavity module 22. When all parameters of the first resonant conversion circuit 10 and the second resonant conversion circuit 20 are consistent, the currents flowing through the first resonant cavity module 12 and the second resonant cavity module 22 are also consistent, so that the voltage across the winding of the first coupling inductor 30 does not change, and the first coupling inductor 30 at this time only corresponds to a wire, and has no other additional effects on the circuit. When all parameters of the first resonant cavity module 12 and the second resonant cavity module 22 are inconsistent or the control signals input to the first resonant cavity module 12 and the second resonant cavity module 22 are inconsistent, the currents flowing through the first resonant cavity module 12 and the second resonant cavity module 22 are also different, so that the difference between the currents in the first resonant cavity module 12 and the second resonant cavity module 22 changes, and the first coupling inductor 30 generates an induced electromotive force to suppress this change, thereby achieving the effect of balancing the currents in the first resonant cavity module 12 and the second resonant cavity module 22, i.e. enabling each switch tube of the first switch module 11 and each switch tube of the second switch module 21 to work at the same current level.

[0057] For example, the resonant converter circuit 100 is taken as an example for description. Figure 3 As shown in the circuit structure of the resonant converter circuit.

[0058] In an embodiment, as shown in the circuit structure of the resonant converter circuit. Figure 3As shown, the first switch module 11 includes a first bridge arm unit 111 and a second bridge arm unit 112, the first bridge arm unit 111 and the second bridge arm unit 112 are connected in parallel, and the first bridge arm unit 111 and the second bridge arm unit 112 are the resonance cavity of the first resonant conversion circuit 10. The first resonant cavity module 12 and the second resonant cavity module 22 are both arranged in the resonance cavity. The first bridge arm unit 111 includes a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, and a fourth switch tube Q4. The second bridge arm unit 112 includes a fifth switch tube Q5, a sixth switch tube Q6, a seventh switch tube Q7, and an eighth switch tube Q8.

[0059] Specifically, the first switch tube Q1 and the second switch tube Q2 are connected in series in the same direction, the second end of the first switch tube Q1 and the second end of the third switch tube Q3 are connected, and the first end of the first switch tube Q1 and the second end of the second switch tube Q2 are connected. The third switch tube Q3 and the fourth switch tube Q4 are connected in series in the same direction, the first end of the third switch tube Q3 and the second end of the fourth switch tube Q4 are connected, and the first end of the second switch tube Q2 and the first end of the fourth switch tube Q4 are connected.

[0060] The fifth switch tube Q5 and the sixth switch tube Q6 are connected in series in the same direction, the second end of the fifth switch tube Q5 and the second end of the seventh switch tube Q7 are connected, and the first end of the fifth switch tube Q5 and the second end of the sixth switch tube Q6 are connected. The seventh switch tube Q7 and the eighth switch tube Q8 are connected in series in the same direction, the first end of the seventh switch tube Q7 and the first end of the eighth switch tube Q8 are connected, and the first end of the sixth switch tube Q6 and the first end of the eighth switch tube Q8 are connected.

[0061] At the same time, the control end of the first switch tube Q1, the control end of the second switch tube Q2, the control end of the third switch tube Q3, the control end of the fourth switch tube Q4, the control end of the fifth switch tube Q5, the control end of the sixth switch tube Q6, the control end of the seventh switch tube Q7, and the control end of the eighth switch tube Q8 are all connected to the control unit 40. The control unit 40 outputs a control signal to control the switching state of each switch tube. The switching state of each switch tube refers to the on state or off state of each switch tube.

[0062] It should be understood that the first switch tube Q1, the second switch tube Q2, the third switch tube Q3, the fourth switch tube Q4, the fifth switch tube Q5, the sixth switch tube Q6, the seventh switch tube Q7 and the eighth switch tube Q8 can be selected from one of a triode, a MOS tube or an IGBT switch tube, and the first switch tube Q1, the second switch tube Q2, the third switch tube Q3, the fourth switch tube Q4, the fifth switch tube Q5, the sixth switch tube Q6, the seventh switch tube Q7 and the eighth switch tube Q8 can be all the same or different, for example, the first switch tube Q1, the second switch tube Q2, the third switch tube Q3, the fourth switch tube Q4, the fifth switch tube Q5, the sixth switch tube Q6, the seventh switch tube Q7 and the eighth switch tube Q8 are all selected from a MOS tube.

[0063] In the following embodiments, the first switch tube Q1, the second switch tube Q2, the third switch tube Q3, the fourth switch tube Q4, the fifth switch tube Q5, the sixth switch tube Q6, the seventh switch tube Q7 and the eighth switch tube Q8 are all selected from a MOS tube as an example for description.

[0064] That is, the gate of the first MOS tube Q1 is the control end of the first switch tube Q1, the source of the first MOS tube Q1 is the first end of the first switch tube Q1, and the drain of the first MOS tube Q1 is the second end of the first switch tube Q1. As for the second switch tube Q2, the third switch tube Q3, the fourth switch tube Q4, the fifth switch tube Q5, the sixth switch tube Q6, the seventh switch tube Q7 and the eighth switch tube Q8, the pin correspondence relationship when the above switch tubes are selected from a MOS tube is similar to that of the first switch tube Q1, which is easily understood by those skilled in the art, and will not be described here.

[0065] In an embodiment, the first coupling inductor L1 includes a first winding N1 and a second winding N2, the first winding N1 is connected with the first resonant cavity module 12, and the second winding N2 is connected with the second resonant cavity module 22.

[0066] Further, the first resonant cavity module 12 includes a first resonant inductor L2 and a first transformer T1, and the connection point between the source of the first switch tube Q1 and the drain of the second switch tube Q2 is connected with the first end of the first resonant inductor L2, the second end of the first resonant inductor L2 is connected with the same-named end of the first winding N1, that is, the second end of the first winding N1 is connected with the second end of the first winding N1, and the different-named end of the first winding N1, that is, the first end of the first winding N1 is connected with the same-named end of the primary winding T11 of the first transformer T1.

[0067] Optionally, the second resonant cavity module 22 comprises a second resonant inductor L3 and a second transformer T2, and the connection point between the source of the fifth switch tube Q5 and the drain of the sixth switch tube Q6 is connected with the first end of the second resonant inductor L3, the second end of the second resonant inductor L3 is connected with the homonymous end of the second winding N2, that is, the second end of the second resonant inductor L3 is connected with the fourth end in the second winding N2, and the heteronymous end of the second winding N2, that is, the third end of the second winding N2 is connected with the homonymous end of the primary winding T21 of the second transformer T2.

[0068] It can be understood that Figure 3 The end of the first coupling inductor L1, the transformer T1 or the transformer T2 in which the small black dot is located is the homonymous end, for example, the second end of the first winding N1 is the homonymous end, and vice versa, for example, the first end of the first winding N1 is the heteronymous end. Among them, the homonymous end is the basis for judging the phase of current or electromotive force between mutual inductors, and the homonymous end specifically refers to: when two mutual inductors are connected with current, the current inflow end of the two coils is called the homonymous end (also called the same polarity end) when the generated magnetic flux directions are the same, and vice versa.

[0069] Optionally, the first switch module 11 further comprises a first filter capacitor C1, and the second switch module further comprises a second filter capacitor C2, wherein the first filter capacitor C1 is connected in parallel with the first bridge arm unit 111, and the second filter capacitor C2 is connected in parallel with the second bridge arm unit 112, that is, one end of the first filter capacitor C1 is connected with the drain of the first MOS tube Q1, the other end of the first filter capacitor C1 is connected with the source of the second MOS tube Q2, one end of the second filter capacitor C2 is connected with the drain of the fifth MOS tube, and the other end of the second filter capacitor C2 is connected with the source of the sixth MOS tube Q6.

[0070] In actual application, the input signals of the first MOS tube Q1 and the fifth MOS tube Q5 are the same PWM signal, which is denoted as PWMA, the input signals of the second MOS tube Q2 and the sixth MOS tube Q6 are the same PWM signal, which is denoted as PWMB, the input signals of the third MOS tube Q3 and the seventh MOS tube Q7 are the same PWM signal, which is denoted as PWMC, and the input signals of the fourth MOS tube Q4 and the eighth MOS tube Q8 are the same PWM signal, which is denoted as PWMD, and PWMA and PWMB are complementary PWM waves with dead zones, and PWMC and PWMD are complementary PWM waves with dead zones. Among them, as Figure 4The waveforms PWM1b and PWM2b shown are PWM waves with dead zone complement. Assuming that the waveform of PWMA is PWM1b, and the waveform of PWMB is PWM2b, during the time period T1, although the second switch Q2 or the sixth MOS Q6 is turned off due to the low level of PWM2b, the first switch Q1 or the fifth MOS Q5 will not be immediately turned on, but will be turned on after the time period T1. Similarly, during the time period T2, although the first switch Q1 is turned off due to the low level of PWM1b, the second switch Q2 will not be immediately turned on, but will be turned on after the time period T2. In this way, the second switch Q2 or the sixth MOS Q6 will not be turned on until the first switch Q1 or the fifth MOS Q5 is completely turned off, preventing various abnormal conditions such as the simultaneous conduction of the first switch Q1 and the second switch Q2. It should be understood that the time period T1 or the time period T2 can be set according to actual needs, which is not limited here.

[0071] The input power supply 300 is connected to the input end of the resonant converter circuit through the V+ pin and the V- pin, and then the control unit 40 outputs the PWMA signal, the PWMB signal, the PWMC signal and the PWMD to control each switch, thereby realizing the regulation process of the input power supply 300. At this time, the current in the first resonant cavity module 12 is IL2, and the current direction is from the first resonant inductor L2 to the first winding N1; the current in the second resonant cavity module 22 is IL3, and the current direction is from the second resonant inductor L3 to the second winding N2.

[0072] Therefore, if the first coupling inductor L1 is selected to have a winding ratio of 1:1, and the first winding N1 and the second winding N2 are wound on the same magnetic core. Then, when the current IL2 changes, the magnetic flux generated by the current also changes. Since there is a magnetic relationship between the first winding N1 and the second winding N2, the current IL2 flowing through the first winding N1 will induce an electromotive force on the second winding N2. Similarly, the current IL3 flowing through the second winding N2 will induce an electromotive force on the first winding N1.

[0073] And since the inductance L N1 of the first winding N1 N2 is equal to the inductance L N1 of the second winding N2, the coupling coefficient is 1, then the voltage V N2 between the two ends (the first end and the second end) of the first winding N1 N2 satisfies the following relationship:

[0074]

[0075] From the above equation, it can be seen that if all corresponding parameters of the first resonant transformer circuit 10 and the second resonant transformer circuit 20 are the same, then the current IL2 = the current IL3, and V can be obtained. N1 =V N2 =0. At this time, the voltage across the first winding N1 and the second winding N2 is 0. Therefore, the first coupling inductor L1 is equivalent to a wire and has no effect on the circuit.

[0076] If some or all of the parameters in the first resonant converter circuit 10 and the second resonant converter circuit 20 are different, then current IL2 ≠ current IL3. That is, the difference between the current in the resonant cavity of the first resonant converter circuit 10 and the current in the resonant cavity of the second resonant converter circuit 20 will change. At this time, due to V N1 With V N2 If neither is zero, then the first winding N1 and the second winding N2 will generate an induced electromotive force to suppress the above changes, thereby achieving the effect of balancing the current in the resonant cavity of the first resonant converter circuit 10 and the current in the resonant cavity of the second resonant converter circuit 20, so that each switch and rectifier circuit 200 in the resonant converter circuit 100 will work at the same current level. For example, assuming the voltage across the first filter capacitor C1 is 450V, the voltage across the second filter capacitor C2 is 400V, and the output voltage of the resonant converter circuit 100 is 27.5V, the output current is 275A, and the total power is 7.5KW, then for this circuit, if the first coupling inductor L1 is connected, the deviation between the current in the resonant cavity of the first resonant converter circuit 10 and the current in the resonant cavity of the second resonant converter circuit 20 is less than 1%, that is, the current in the resonant cavity of the first resonant converter circuit 10 and the current in the resonant cavity of the second resonant converter circuit 20 are basically the same; however, if the first coupling inductor L1 is not connected, the deviation between the current in the resonant cavity of the first resonant converter circuit 10 and the current in the resonant cavity of the second resonant converter circuit 20 exceeds 60%, which may damage the power devices, thus preventing the resonant converter circuit 100 from working properly.

[0077] In another embodiment, different input power supplies can be used for the first resonant converter circuit 10 and the second resonant converter circuit 20, such as... Figure 5 As shown, the first input power supply is connected to the first resonant converter circuit 10 through V1+ and V1-, and the second input power supply is connected to the first resonant converter circuit 20 through V2+ and V2-.

[0078] In another embodiment, the first resonant converter circuit 10 and the second resonant converter circuit 20 can also be powered by the same bus, such as... Figure 6 As shown, the input power supply is connected to the first resonant converter circuit 10 and the first resonant converter circuit 20 via V+ and V-.

[0079] It can be understood that the control scheme adopted by the circuit as shown in Figure 5 or Figure 6 is the same as that of the circuit as shown in Figure 3 which is within the scope of easy understanding of those skilled in the art and will not be described here.

[0080] Optionally, as shown in Figure 7 , the resonant converter circuit 100 further comprises a third resonant conversion circuit 50 and a second coupling inductor 60, or can further comprise a fourth resonant conversion circuit and a third coupling inductor, that is, the resonant converter circuit 100 can further comprise an Nth resonant conversion circuit and a Kth coupling inductor, wherein the Nth resonant conversion circuit comprises an Nth switch module and an Nth resonant cavity module, and N and K are both positive integers. It can be understood that when N is 2 and K is 1, it is the technical scheme as shown in Figure 3 or Figure 5 or Figure 6 .

[0081] Taking the case that the resonant converter circuit 100 further comprises a third resonant conversion circuit 50 and a second coupling inductor 60 as an example for description.

[0082] Please refer to Figure 8 , the third resonant conversion circuit 50 comprises a third switch module 51 and a third resonant cavity module 52, wherein the third switch module 51 comprises a fifth bridge arm unit and a sixth bridge arm unit, the fifth bridge arm unit and the sixth bridge arm unit are connected in parallel, the third resonant cavity module 52 comprises a third resonant inductor L4 and a third transformer T3, the third resonant cavity module 52 is connected with the fifth bridge arm unit and the sixth bridge arm unit respectively, and the second coupling inductor is connected with the second resonant cavity module and the third resonant cavity module respectively.

[0083] Specifically, the first bridge arm unit comprises a ninth switch tube Q9 and a tenth switch tube Q10, the second bridge arm unit comprises an eleventh switch tube Q11 and a twelfth switch tube Q12, and the second coupling inductor L5 comprises a third winding N3 and a fourth winding N4. The connection point between the source of the ninth switch tube Q9 and the drain of the tenth switch tube Q10 is connected with the first end of the third resonant inductor L4, the second end of the third resonant inductor L4 is connected with the non-name end of the fourth winding N4 (the 8th end of the fourth winding N4), the same name end of the fourth winding N4 (the 7th end of the fourth winding N4) is connected with the same name end of the primary winding of the third transformer T3, the same name end of the third winding N3 (the 6th end of the third winding N3) is connected with the 3rd end of the second winding N2, and the non-name end of the third winding N3 (the 5th end of the third winding N3) is connected with the same name end of the primary winding of the second transformer T2.

[0084] Based on the above analysis, it can be seen that the first input power supply is connected to the first resonant converter circuit 10 through the V1+ port and the V1- port, the second input power supply is connected to the second resonant converter circuit 20 through the V2+ port and the V2- port, and the first input power supply is connected to the third resonant converter circuit 50 through the V3+ port and the V3- port. If all the parameters of the first resonant converter circuit 10, the second resonant converter circuit 20, and the third resonant converter circuit 50 are the same, then the first coupling inductor L1 and the second coupling inductor L5 can be regarded as wires and have no effect on the circuit.

[0085] If the parameters of the first resonant converter circuit 10 and the second resonant converter circuit 20 are partially or completely inconsistent, or if the duty cycle of the input control signal of the switching transistor of the first resonant converter circuit 10 is inconsistent with that of the input control signal of the switching transistor of the second resonant converter circuit 20, then the currents of the first resonant converter circuit 10 and the second resonant converter circuit 20 will also be different. In this case, the first coupling inductor L1 will generate a back electromotive force to achieve current sharing between the first resonant converter circuit 10 and the second resonant converter circuit 20. Similarly, if the parameters of the second resonant converter circuit 20 and the third resonant converter circuit 50 are partially or completely inconsistent, or if the duty cycle of the input control signal of the switching transistor of the third resonant converter circuit 50 is inconsistent with that of the input control signal of the switching transistor of the second resonant converter circuit 20, then the currents of the third resonant converter circuit 50 and the second resonant converter circuit 20 will also be different. In this case, the second coupling inductor L5 will generate a back electromotive force to achieve current sharing between the third resonant converter circuit 50 and the second resonant converter circuit 20.

[0086] It should be noted that, for Figure 8 The circuit shown is composed of Figure 5 The circuit shown can be further enhanced by adding a third resonant converter circuit and a second coupling inductor. Therefore, for Figure 3 or Figure 6 The circuit shown can also have the same characteristics as... Figure 8 Similar variations, which are readily understood by those skilled in the art, will not be elaborated upon here.

[0087] The resonant converter circuit 100 provided by the application comprises at least a first resonant conversion circuit 10, a second resonant conversion circuit 20, a first coupling inductor 30 and a control unit 40, the first resonant conversion circuit 10 comprises a first switch module 11 and a first resonant cavity module 12, the second resonant conversion circuit 20 comprises a second switch module 21 and a second resonant cavity module 22, the first switch module 11 is connected with the first resonant cavity module 12, the second switch module 21 is connected with the second resonant cavity module 22, the control unit 40 is connected with the first switch module 11 and the second switch module 21 respectively, and the first coupling inductor 30 is connected with the first resonant cavity module 12 and the second resonant cavity module 22 respectively, therefore, since the first coupling inductor 30 is arranged between the first resonant cavity module 12 and the second resonant cavity module 22, when the current difference of the first resonant cavity module 12 or the second resonant cavity module 22 changes, the first coupling inductor 30 can generate an induced electromotive force to inhibit the change, so that the current balancing effect is realized, that is, the current balancing control is realized by adding the first coupling inductor 30 which is a relatively simple hardware structure, and the required cost is low.

[0088] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the application, and not to limit them; under the idea of the application, the technical features in the above examples or different examples can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of the application as described above, which are not provided in details for simplicity; although the application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: the technical solutions recorded in the foregoing examples can still be modified, or some technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. A resonant converter circuit, characterized in that, include: First resonant converter circuit, second resonant converter circuit, first coupling inductor and control unit; The first resonant converter circuit includes a first switching module and a first resonant cavity module, wherein the first switching module is connected to the first resonant cavity module; The second resonant converter circuit includes a second switching module and a second resonant cavity module, and the second switching module is connected to the second resonant cavity module; The control unit is connected to the first switch module and the second switch module respectively, and the control unit is used to output control signals to control the switching state of the first switch module and the second switch module; The first coupling inductor is connected to the first resonant cavity module and the second resonant cavity module respectively, and the first coupling inductor is used to adjust the current in the first resonant cavity module and the second resonant cavity module. The resonant converter circuit also includes a third resonant converter circuit and a second coupling inductor; The third resonant converter circuit includes: The third switch module includes a fifth bridge arm unit and a sixth bridge arm unit, which are connected in parallel. The third resonant cavity module is connected to the fifth bridge arm unit and the sixth bridge arm unit respectively; The second coupling inductor is connected to both the second resonant cavity module and the third resonant cavity module. The second coupled inductor includes a third winding and a fourth winding; The same-name end of the third winding is connected to the first coupling inductor, and the opposite-name end of the third winding is connected to the second resonant cavity module; Both the same-named and different-named ends of the fourth winding are connected to the third resonant cavity module.

2. The resonant converter circuit according to claim 1, characterized in that, The first coupled inductor includes a first winding and a second winding, the first winding being connected to the first resonant cavity module and the second winding being connected to the second resonant cavity module.

3. The resonant converter circuit according to claim 2, characterized in that, The first switch module includes a first bridge arm unit and a second bridge arm unit, which are connected in parallel. The first resonant cavity module includes a first resonant inductor and a first transformer; The first end of the first resonant inductor is connected to the first bridge arm unit, the second end of the first resonant inductor is connected to the same-name end of the first winding, the same-name end of the primary winding of the first transformer is connected to the opposite-name end of the first winding, and the opposite-name end of the primary winding of the first transformer is connected to the second bridge arm unit.

4. The resonant converter circuit according to claim 3, characterized in that, The first bridge arm unit includes a first switch and a second switch connected in series in the same direction, and the second bridge arm unit includes a third switch and a fourth switch. The second end of the first switching transistor is connected to the second end of the third switching transistor, and the first end of the second switching transistor is connected to the first end of the fourth switching transistor. The connection point between the first end of the first switching transistor and the second end of the second switching transistor is connected to the first end of the first resonant inductor, and the connection point between the first end of the third switching transistor and the second end of the fourth switching transistor is connected to the opposite end of the primary winding of the first transformer. The control terminals of the first switch, the second switch, the third switch, and the fourth switch are all connected to the control unit.

5. The resonant converter circuit according to claim 2, characterized in that, The second switch module includes a third bridge arm unit and a fourth bridge arm unit, which are connected in parallel. The second resonant cavity module includes a second resonant inductor and a second transformer; The first end of the second resonant inductor is connected to the third bridge arm unit, the second end of the second resonant inductor is connected to the opposite end of the second winding, the same end of the primary winding of the second transformer is connected to the opposite end of the third winding, and the opposite end of the primary winding of the second transformer is connected to the fourth bridge arm unit.

6. The resonant converter circuit according to claim 5, characterized in that, The third bridge arm unit includes a fifth switch and a sixth switch connected in series in the same direction, and the fourth bridge arm unit includes a seventh switch and an eighth switch. The second end of the fifth switch is connected to the second end of the seventh switch, and the first end of the sixth switch is connected to the first end of the eighth switch. The connection point between the first end of the fifth switch and the second end of the sixth switch is connected to the first end of the second resonant inductor, and the connection point between the first end of the seventh switch and the second end of the eighth switch is connected to the opposite end of the primary winding of the second transformer. The control terminals of the fifth, sixth, seventh, and eighth switching transistors are all connected to the control unit.

7. The resonant converter circuit according to claim 3 or 4, characterized in that, The first switching module further includes a first filter capacitor, and the second switching module further includes a second filter capacitor; The first filter capacitor is connected in parallel with the first bridge arm unit, and the second filter capacitor is connected in parallel with the second bridge arm unit.

8. A resonant converter, characterized in that, The resonant converter includes a rectifier module and a resonant converter circuit as described in any one of claims 1-7, wherein the resonant converter circuit is connected to the rectifier module; The resonant converter circuit is used for voltage conversion of the input power supply; The rectifier module is used to rectify the input power after voltage conversion in order to provide power supply voltage for the load.

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