Control device and method for soft switching of full-bridge inverter circuit

Abstract

The invention discloses a control device and method for a soft switch of a full-bridge inverter circuit, and relates to the technical field of phase-shift full bridges, and the device comprises the full-bridge inverter circuit which converts a direct current inputted by a direct current input end into an alternating current based on the control of a controller, and outputs the alternating current to a transformer; the transformer is used for boosting the alternating current output by the full-bridge inverter circuit and then outputting the alternating current to the rectifier module; the rectifier module converts the alternating current boosted by the transformer into direct current and outputs the direct current to a direct current load; and the soft switching control module is used for generating a conduction signal of the lagging bridge arm based on the power input by the direct-current power supply and the transformation multiple of the transformer. When the controller controls the controllable switch of the full-bridge inverter circuit, a conduction signal of a lagging bridge arm is determined through a soft switching control module connected with the secondary side of the transformer. The leading bridge arm is controlled based on the normal full-bridge inverter circuit conduction period, and then the lagging bridge arm is controlled based on the signal generated by the soft switching control module, so that the control strategy is adjusted according to the input voltage, and the stability of the full-bridge inverter circuit is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of phase-shifted full-bridge technology, and in particular to a control device and method for a soft switch of a full-bridge inverter circuit. Background Art

[0002] The input end of the full-bridge inverter circuit is connected to direct current, and two controllable switches are arranged on the upper bridge arm and the lower bridge arm of the full-bridge inverter circuit. The full-bridge inverter circuit composed of four controllable switches can convert direct current into alternating current. Specifically, the full-bridge inverter circuit includes a leading bridge arm and a lagging bridge arm, and two controllable switches are arranged on the leading bridge arm and the lagging bridge arm. The two controllable switches on the leading bridge arm are not turned on at the same time, and the two controllable switches on the lagging bridge arm are not turned on at the same time. In practical applications, the controllable switch of the upper bridge arm of the leading bridge arm and the controllable switch of the lower bridge arm of the lagging bridge arm are turned on at the same time, and the controllable switch of the lower bridge arm of the leading bridge arm and the controllable switch of the upper bridge arm of the lagging bridge arm are turned on at the same time. In order to realize soft switching, that is, the controllable switch of the lower bridge arm of the lagging bridge arm is turned on later than the controllable switch of the upper bridge arm of the leading bridge arm, and the controllable switch of the upper bridge arm of the lagging bridge arm is turned on later than the controllable switch of the lower bridge arm of the leading bridge arm, it is necessary to set the control parameters of the controllable switch to realize soft switching. However, the control parameters set by the soft switch need to change with the input voltage, and a fixed parameter satisfies a smaller voltage range, which increases the complexity of control and also affects the stability of the full-bridge inverter circuit. Summary of the invention

[0003] The purpose of the present invention is to provide a control device and method for a soft switch of a full-bridge inverter circuit, which realizes adjusting the control strategy according to the input voltage and improves the stability of the full-bridge inverter circuit.

[0004] In order to solve the above technical problems, the present invention provides a control device for a full-bridge inverter circuit soft switch, comprising:

[0005] A full-bridge inverter circuit, the full-bridge inverter circuit comprising a leading bridge arm and a lagging bridge arm, the control ends of the two controllable switches on the leading bridge arm and the control ends of the two controllable switches on the lagging bridge arm are both connected to the output end of the controller, the DC input end of the full-bridge inverter circuit is connected to a DC power supply, and the AC output end is connected to the primary side of the transformer, and is used for converting the DC power input from the DC input end into AC power and outputting it to the transformer based on the control of the controller;

[0006] The transformer, the secondary side of which is connected to the input end of the rectifier module and the input end of the controller respectively, is used to boost the AC power output by the full-bridge inverter circuit and then output it to the rectifier module;

[0007] The rectifier module, whose output end is connected to a DC load, is used to convert the AC power boosted by the transformer into DC power and output it to the DC load;

[0008] A soft switch control module, wherein a first end of the soft switch control module is connected to the secondary side of the transformer, and a second end of the soft switch control module is connected to the input end of the controller, and is used to generate a conduction signal of the lagging bridge arm based on the power input by the DC power supply and the transformation multiple of the transformer;

[0009] The controller is used to control the on and off of the two controllable switches of the leading bridge arm according to the conduction period of the full-bridge inverter circuit, and controls the on and off of the two controllable switches of the lagging bridge arm based on the conduction signal of the lagging bridge arm, wherein the controllable switch of the lower bridge arm of the lagging bridge arm is turned on later than the controllable switch of the upper bridge arm of the leading bridge arm, and the controllable switch of the upper bridge arm of the lagging bridge arm is turned on later than the controllable switch of the lower bridge arm of the leading bridge arm.

[0010] On the other hand, the full-bridge inverter circuit includes a first controllable switch, a second controllable switch, a third controllable switch and a fourth controllable switch;

[0011] The first controllable switch is arranged on the lower bridge arm of the leading bridge arm, the second controllable switch is arranged on the upper bridge arm of the leading bridge arm, the third controllable switch is arranged on the lower bridge arm of the lagging bridge arm, and the fourth controllable switch is arranged on the upper bridge arm of the lagging bridge arm;

[0012] The output positive electrode of the DC power supply is respectively connected to the first end of the second controllable switch and the first end of the fourth controllable switch; the common end to which the second end of the second controllable switch is connected to the first end of the first controllable switch is connected as the first output end of the full-bridge inverter circuit and the first end of the primary coil of the transformer; the second end of the fourth controllable switch is connected to the first end of the third controllable switch and the common end connected is connected to the second end of the primary coil of the transformer as the second output end of the full-bridge inverter circuit; the second end of the first controllable switch and the second end of the third controllable switch are both connected to the output negative electrode of the DC power supply; and the control ends of the first controllable switch, the second controllable switch, the third controllable switch and the fourth controllable switch are all connected to the controller for being turned on or off based on the control of the controller.

[0013] On the other hand, the first controllable switch includes a first transistor, a first diode and a first parasitic capacitor, the second controllable switch includes a second transistor, a second diode and a second parasitic capacitor, the third controllable switch includes a third transistor, a third diode and a third parasitic capacitor, and the fourth controllable switch includes a fourth transistor, a fourth diode and a fourth parasitic capacitor;

[0014] A cathode of the first diode is connected to a first end of the first transistor and a first end of the first parasitic capacitor, an anode of the first diode is connected to a second end of the first transistor and a second end of the first parasitic capacitor, a cathode of the second diode is connected to a first end of the second transistor and a first end of the second parasitic capacitor, an anode of the second diode is connected to a second end of the second transistor and a second end of the second parasitic capacitor, a cathode of the third diode is connected to a first end of the third transistor and a first end of the third parasitic capacitor, an anode of the third diode is connected to a second end of the third transistor and a second end of the third parasitic capacitor, a cathode of the fourth diode is connected to a first end of the fourth transistor and a first end of the fourth parasitic capacitor, and an anode of the fourth diode is connected to a second end of the fourth transistor and a second end of the fourth parasitic capacitor.

[0015] On the other hand, the rectifier module includes a resonant inductor, a rectifier diode circuit and a resonant capacitor circuit, the rectifier diode circuit includes a fifth diode and a sixth diode, and the resonant capacitor circuit includes a first capacitor and a second capacitor;

[0016] The first end of the resonant inductor is connected to the first end of the secondary coil of the transformer, and the common end of the connection is connected to the positive power supply electrode of the load, the second end of the resonant inductor is connected to the anode of the fifth diode and the cathode of the sixth diode, the cathode of the fifth diode is connected to the first end of the first capacitor, the second end of the first capacitor is connected to the first end of the second capacitor, and the common end of the connection is connected to the second end of the secondary coil, the anode of the sixth diode is connected to the second end of the second capacitor, and the common end of the connection is connected to the negative power supply electrode of the load;

[0017] The resonant inductor and the rectifier diode circuit are used to convert alternating current into direct current, and the resonant inductor and the resonant capacitor circuit are used to form a resonant body.

[0018] On the other hand, the soft switch control module includes a mutual inductor, a seventh diode, a first integration module, a first reset switch, a first comparator, a second comparator, an inverter and a first AND gate;

[0019] The first end of the primary coil of the mutual inductor is connected to the second end of the secondary coil of the transformer, the second end of the primary coil of the mutual inductor is connected to the rectifier module, the first end of the first secondary coil of the mutual inductor is connected to the anode of the seventh diode, the cathode of the seventh diode is connected to the input end of the first integration module, the output end of the first integration module is connected to the first end of the first reset switch and the inverting input end of the first comparator, the positive input end of the first comparator is connected to the first reference voltage, the output end of the first comparator is connected to the first input end of the first AND gate, the second end of the first reset switch is connected to the second end of the first secondary coil and the common end of the connections is grounded, the positive input end and the inverting input end of the second comparator are both connected to the second reference voltage, the first end of the second secondary coil of the mutual inductor is also connected to the inverting input end of the second comparator, the output end of the second comparator is respectively connected to the reset end of the first reset switch and the input end of the inverter, the output end of the inverter is connected to the second input end of the first AND gate, and the output signal of the first AND gate is used as the conduction signal of the upper bridge arm of the lagging bridge arm;

[0020] The controller is specifically used to control the on-cycle of the full-bridge inverter circuit to turn on and off the two controllable switches of the leading bridge arm, control the controllable switch of the upper bridge arm of the lagging bridge arm based on the on-signal of the upper bridge arm of the lagging bridge arm, and control the controllable switch of the lower bridge arm of the lagging bridge arm based on the reverse signal of the on-signal of the upper bridge arm of the lagging bridge arm;

[0021] The seventh diode is used for reverse protection, the first integration module is used for integrating the current to obtain the voltage, the first reset switch is used for turning on when the voltage of the second secondary coil is lower than the second reference voltage, the first comparator is used for comparing the voltage of the first secondary coil with the first reference voltage, and the second comparator is used for comparing the voltage of the second secondary coil with the second reference voltage.

[0022] On the other hand, the soft switch control module further includes an eighth diode, a second integration module, a second reset switch, a third comparator and a second AND gate;

[0023] The anode of the eighth diode is connected to the first end of the third secondary coil of the mutual inductor, the second end of the third secondary coil of the mutual inductor is grounded, the cathode of the eighth diode is connected to the input end of the second integration module, the output end of the second integration module is connected to the first end of the second reset switch and the inverting input end of the third comparator, the second end of the second reset switch is grounded, the non-inverting input end of the third comparator is connected to the first reference voltage, the output end of the third comparator is connected to the first input end of the second AND gate, the output end of the second comparator is connected to the second input end of the second AND gate, and the output signal of the second AND gate is used as the turn-on signal of the lower bridge arm of the lagging bridge arm;

[0024] The eighth diode is used for reverse protection, the second integration module is used for integrating the current to obtain the voltage, the second reset switch is used for turning on when the voltage of the second secondary coil is higher than the second reference voltage, and the third comparator is used for comparing the voltage on the second secondary coil with the first reference voltage.

[0025] The controller is specifically used to control the conduction and disconnection of the two controllable switches of the leading bridge arm according to the conduction period of the full-bridge inverter circuit, control the controllable switch of the upper bridge arm of the lagging bridge arm based on the conduction signal of the upper bridge arm of the lagging bridge arm, and control the controllable switch of the lower bridge arm of the lagging bridge arm based on the conduction signal of the lower bridge arm of the lagging bridge arm.

[0026] In order to solve the above technical problems, the present invention also provides a control method for a full-bridge inverter circuit soft switch, and a controller used in a control device for a full-bridge inverter circuit soft switch, comprising:

[0027] Acquiring the power of the direct current of the full-bridge inverter circuit input into the control device of the full-bridge inverter circuit soft switch;

[0028] Determine a phase shift value between an advanced bridge arm and a lagging bridge arm of the full-bridge inverter circuit according to the power;

[0029] Determine the dead time of the controllable switch of the upper bridge arm and the controllable switch of the lower bridge arm of the lagging bridge arm being turned on according to the phase shift value;

[0030] A soft switch control module in a control device for a soft switch of a full-bridge inverter circuit determines a first reference voltage and a second reference voltage according to the dead time and outputs the voltages to the soft switch;

[0031] The two controllable switches of the leading bridge arm are turned on and off according to the phase shift value, and the two controllable switches of the lagging bridge arm are controlled to be turned on and off based on the turn-on signal of the lagging bridge arm output by the soft switch control module.

[0032] On the other hand, determining the phase shift value between the leading bridge arm and the lagging bridge arm of the full-bridge inverter circuit according to the power includes:

[0033] The phase shift value between the leading bridge arm and the lagging bridge arm of the full-bridge inverter circuit is determined according to the power determination relationship and the power, and the power determination relationship is T ps =f1×f4(f2×f3);

[0034] Wherein, f1 is the first function, and the function value is related to the inductance value L of the resonant inductance of the secondary side of the transformer. r And the capacitance value C of the resonant capacitor circuit of the filter module r is positively correlated, f2 is the second function, and the function value is positively correlated with V o / (n2×V i ) and (n2×V o ×V i ) are negatively correlated with the DC power p o and the conduction period T of the full-bridge inverter circuit s Both are positively correlated, V o is the output voltage to the load, V i is the input DC voltage, n2 is the turns ratio of the primary coil to the secondary coil of the transformer, f3 is the third function, and the function value is related to L r and C r Both were negatively correlated with T s There is a positive correlation, and f4 is the fourth function.

[0035] On the other hand, determining the dead time of the controllable switch of the upper bridge arm and the controllable switch of the lower bridge arm of the lagging bridge arm according to the phase shift value includes:

[0036] The dead time of the controllable switch of the upper bridge arm and the controllable switch of the lower bridge arm of the lagging bridge arm is determined according to the phase shift value and the phase shift value relationship, and the phase shift value relationship is t DT =f5×f6[(f 18 +f7×f 11 +f8) / f 13 ]+f9×f 10 [(f 18 + f 16 ) / f 13 ]-f 12 ;

[0037] Among them, f5 is the fifth function, and the function value is related to L r and C r There is a positive correlation, f6 is the sixth function, f7 is the seventh function, and the function value is related to C r 、n2、V i and V oThere is a positive correlation, f8 is the eighth function, and the function value is related to C r 、n2、V i and V o Negatively correlated, f9 is the ninth function, and the function value is related to L r and C r Negatively correlated, f 10 is the tenth function, f 11 is the eleventh function, , f 12 is the twelfth function, and T s Negatively correlated, f 13 is the thirteenth function, , f 14 is the fourteenth function, and its value is related to p o and T s Negatively correlated, f 15 is the fifteenth function, , f 16 is the sixteenth function, and its value is related to C ds 、n2、V i and V o Positively correlated with C r and C cs Negatively correlated, C cs is the capacitance value of the integral capacitor in the soft switch control module, f 17 is the seventeenth function, and its value is related to C r 、V o Positively correlated, f 18 is the eighteenth function, f 18 =f 17 +f 14 .

[0038] On the other hand, a soft switch control module in a control device for a soft switch of a full-bridge inverter circuit that determines a first reference voltage and a second reference voltage according to the dead time and outputs the voltage to the soft switch includes:

[0039] The first reference voltage is determined according to the dead time and a first reference voltage relationship, wherein the first reference voltage relationship is V ref =f 19 ×(f 21 +f 22 -f 20 )(f 24 -1)+f 19 ×f 20 ×(f 25 -1);

[0040] Among them, V ref is the first reference voltage, f 19 is the nineteenth function, and its value is related to C rand n1 are positively correlated with C cs Negatively correlated, f 20 is the twentieth function, f 20 =n2V i , f 21 is the twenty-first function, and its value is related to V o Positively correlated, f 22 is the twenty-second function, and its value is related to p o and T s Positively correlated with C r and V o Negatively correlated, f 23 is the twenty-third function, and its value is related to L r and C r Negatively correlated, f 24 is the twenty-fourth function, f 24 =cos{f 23 ×[(1-2D1)T s +t DT ]},f 25 is the twenty-fifth function, f 25 =cos{f 23 ×[(1-2D1)T s ]}, D1 is the duty cycle, D1=T ps / T s , T s is the conduction period of the full-bridge inverter circuit;

[0041] The second reference voltage is determined according to its own power supply voltage, and the expression of the second reference voltage is VDD / 2, wherein VDD is its own power supply voltage.

[0042] The present application provides a control device and method for a soft switch of a full-bridge inverter circuit, which relates to the field of phase-shifted full-bridge technology, including: a full-bridge inverter circuit, which converts the direct current input from the DC input end into alternating current based on the control of a controller and outputs it to a transformer; a transformer, which boosts the alternating current output from the full-bridge inverter circuit and outputs it to a rectifier module; a rectifier module, which converts the alternating current boosted by the transformer into direct current and outputs it to a DC load; a soft switch control module, which generates a conduction signal of a lagging bridge arm based on the power input of the DC power supply and the transformer transformation multiple. When the controller controls the controllable switch of the full-bridge inverter circuit, the conduction signal of the lagging bridge arm is determined by the soft switch control module connected to the secondary side of the transformer. The leading bridge arm is controlled based on the normal conduction period of the full-bridge inverter circuit, and the lagging bridge arm is controlled based on the signal generated by the soft switch control module, so that the control strategy is adjusted according to the input voltage, and the stability of the full-bridge inverter circuit is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the prior art and the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0044] Figure 1 A structural schematic diagram of a control device for a full-bridge inverter circuit soft switch provided by the present invention;

[0045] Figure 2 A structural schematic diagram of a soft switch control module provided by the present invention;

[0046] Figure 3 A numerical schematic diagram of device voltage in a control device for a full-bridge inverter circuit soft switch provided by the present invention;

[0047] Figure 4 A numerical schematic diagram of device voltages in another full-bridge inverter circuit soft switch control device provided by the present invention;

[0048] Figure 5 The present invention provides a flow chart of a method for controlling a soft switch of a full-bridge inverter circuit. DETAILED DESCRIPTION

[0049] The core of the present invention is to provide a control device and method for a soft switch of a full-bridge inverter circuit, which realizes adjusting the control strategy according to the input voltage and improves the stability of the full-bridge inverter circuit.

[0050] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] Figure 1 The present invention provides a structural schematic diagram of a full-bridge inverter circuit soft switch control device, the full-bridge inverter circuit 1 soft switch control device comprises:

[0052] A full-bridge inverter circuit 1, the full-bridge inverter circuit 1 includes a leading bridge arm and a lagging bridge arm, the control ends of the two controllable switches on the leading bridge arm and the control ends of the two controllable switches on the lagging bridge arm are both connected to the output end of the controller 4, the DC input end of the full-bridge inverter circuit 1 is connected to a DC power supply, and the AC output end is connected to the primary side of the transformer TR1, and is used for converting the DC power input from the DC input end into AC power based on the control of the controller 4 and outputting it to the transformer TR1;

[0053] The transformer TR1, whose secondary side is respectively connected to the input end of the rectifier module 2 and the input end of the controller 4, is used to boost the AC power output by the full-bridge inverter circuit 1 and output it to the rectifier module 2;

[0054] The rectifier module 2, whose output end is connected to the DC load, is used to convert the AC power boosted by the transformer TR1 into DC power and output it to the DC load;

[0055] A soft switch control module 3, wherein a first end of the soft switch control module 3 is connected to the secondary side of the transformer TR1, and a second end of the soft switch control module 3 is connected to the input end of the controller 4, and is used to generate a conduction signal of the lagging bridge arm based on the power input of the DC power supply and the transformation multiple of the transformer TR1;

[0056] The controller 4 is used for controlling the on-cycle of the full-bridge inverter circuit 1 to turn on and off the two controllable switches of the leading bridge arm, and controlling the on and off of the two controllable switches of the lagging bridge arm based on the on-signal of the lagging bridge arm, wherein the controllable switch of the lower bridge arm of the lagging bridge arm is turned on later than the controllable switch of the upper bridge arm of the leading bridge arm, and the controllable switch of the upper bridge arm of the lagging bridge arm is turned on later than the controllable switch of the lower bridge arm of the leading bridge arm.

[0057] The entire circuit includes a DC input power supply Vi, a full-bridge inverter circuit 1, a transformer TR1, a mutual inductor TR2, a rectifier module 2, and an output load R. The DC power supply can be different types such as photovoltaic components, wind energy, and batteries. In the full-bridge inverter circuit 1, controllable switches are provided on the upper and lower bridge arms of the leading bridge arm and the upper and lower bridge arms of the lagging bridge arm, and there are four controllable switches in total. In theory, the two controllable switches of the leading bridge arm are symmetrical, that is, one is turned on and the other is turned off. The controllable switches on the diagonal are a group. During soft start, the controllable switch on the lagging bridge arm needs to be turned on later than the controllable switch on the leading bridge arm. In order to achieve soft start, it is necessary to determine the delay time. The related art often implements the four controllable switches of the full-bridge inverter circuit 1 to work in a soft switching state by giving a fixed parameter, but the soft switching range that can be guaranteed by one parameter is limited. Therefore, when the input voltage range is very wide, it is impossible to achieve that the four controllable switches of the full-bridge inverter circuit 1 work in a soft switching state within the full input voltage range.

[0058] Therefore, a soft switch control module 3 is provided, which is connected to the secondary side of the transformer TR1, and can collect the secondary side voltage of the transformer TR1, and generate a control signal for the lagging bridge arm based on the power of the input voltage and the transformation multiple of the transformer TR1. When controlling the leading bridge arm, the controller 4 can determine the delay time of the lagging bridge arm compared with the leading bridge arm according to the conduction signal of the lagging bridge arm according to the original control cycle, thereby realizing soft start.

[0059] The present application provides a control device and method for the soft switch of a full-bridge inverter circuit 1, which relates to the field of phase-shifted full-bridge technology, including: a full-bridge inverter circuit 1, which converts the direct current input from the direct current input end into alternating current based on the control of a controller 4 and outputs it to a transformer TR1; a transformer TR1, which boosts the alternating current output from the full-bridge inverter circuit 1 and outputs it to a rectifier module 2; a rectifier module 2, which converts the alternating current boosted by the transformer TR1 into direct current and outputs it to a direct current load; a soft switch control module 3, which generates a conduction signal of a lagging bridge arm based on the power input of the direct current power supply and the transformation multiple of the transformer TR1. When the controller 4 controls the controllable switch of the full-bridge inverter circuit 1, the conduction signal of the lagging bridge arm is determined by the soft switch control module 3 connected to the secondary side of the transformer TR1. The leading bridge arm is controlled based on the normal conduction period of the full-bridge inverter circuit 1, and the lagging bridge arm is controlled based on the signal generated by the soft switch control module 3, so that the control strategy is adjusted according to the input voltage, and the stability of the full-bridge inverter circuit 1 is improved.

[0060] Based on the above embodiments:

[0061] Figure 2 A structural schematic diagram of a soft switch control module provided by the present invention;

[0062] In some embodiments, the full-bridge inverter circuit 1 includes a first controllable switch, a second controllable switch, a third controllable switch, and a fourth controllable switch;

[0063] The first controllable switch is arranged on the lower bridge arm of the leading bridge arm, the second controllable switch is arranged on the upper bridge arm of the leading bridge arm, the third controllable switch is arranged on the lower bridge arm of the lagging bridge arm, and the fourth controllable switch is arranged on the upper bridge arm of the lagging bridge arm;

[0064] The output positive electrode of the DC power supply is respectively connected to the first end of the second controllable switch and the first end of the fourth controllable switch, the common end connected to the second end of the second controllable switch and the first end of the first controllable switch is connected to the first end of the primary coil of the transformer TR1 as the first output end of the full-bridge inverter circuit 1, the second end of the fourth controllable switch is connected to the first end of the third controllable switch and the connected common end is connected to the second end of the primary coil of the transformer TR1 as the second output end of the full-bridge inverter circuit 1, the second end of the first controllable switch and the second end of the third controllable switch are both connected to the output negative electrode of the DC power supply, and the control ends of the first controllable switch, the second controllable switch, the third controllable switch and the fourth controllable switch are all connected to the controller 4 for turning on or off based on the control of the controller 4.

[0065] In some embodiments, the first controllable switch includes a first transistor Q1, a first diode D1D1 and a first parasitic capacitor Cds1, the second controllable switch includes a second transistor Q2, a second diode D2D2 and a second parasitic capacitor Cds2, the third controllable switch includes a third transistor Q3, a third diode D3D3 and a third parasitic capacitor Cds3, and the fourth controllable switch includes a fourth transistor Q4, a fourth diode D4D4 and a fourth parasitic capacitor Cds4;

[0066] A cathode of the first diode D1 is connected to a first end of the first transistor Q1 and a first end of the first parasitic capacitor Cds1, an anode of the first diode D1 is connected to a second end of the first transistor Q1 and a second end of the first parasitic capacitor Cds1, a cathode of the second diode D2 is connected to a first end of the second transistor Q2 and a first end of the second parasitic capacitor Cds2, an anode of the second diode D2 is connected to a second end of the second transistor Q2 and a second end of the second parasitic capacitor Cds2, a cathode of the third diode D3 is connected to a first end of the third transistor Q3 and a first end of the third parasitic capacitor Cds3, an anode of the third diode D3 is connected to a second end of the third transistor Q3 and a second end of the third parasitic capacitor Cds3, a cathode of the fourth diode D4 is connected to a first end of the fourth transistor Q4 and a first end of the fourth parasitic capacitor Cds4, and an anode of the fourth diode D4 is connected to a second end of the fourth transistor Q4 and a second end of the fourth parasitic capacitor Cds4.

[0067] Q1 / Q2 / Q3 / Q4 can be a power semiconductor device such as a metal oxide semiconductor field effect transistor MOSFET, a gallium nitride field effect transistor GaN FET, an insulated gate bipolar transistor IGBT, etc. Q1 / Q2 / Q3 / Q4 has its own body diode D1 / D2 / D3 / D4, and has its own parasitic capacitance Cds1 / Cds2 / Cds3 / Cds4 between the D end (drain) and the S end (source) of Q1 / Q2 / Q3 / Q4. When the DS capacitance needs to be increased, an additional parallel capacitor can be connected between the D end (drain) and the S end (source) of Q1 / Q2 / Q3 / Q4.

[0068] In some embodiments, the rectifier module 2 includes a resonant inductor Lr, a rectifier diode circuit and a resonant capacitor circuit, the rectifier diode circuit includes a fifth diode D5 and a sixth diode D6, and the resonant capacitor circuit includes a first capacitor C1 and a second capacitor C2;

[0069] The first end of the resonant inductor Lr is connected to the first end of the secondary coil of the transformer TR1, and the common end of the connection is connected to the positive power supply electrode of the load, the second end of the resonant inductor Lr is connected to the anode of the fifth diode D5 and the cathode of the sixth diode D6, the cathode of the fifth diode D5 is connected to the first end of the first capacitor C1, the second end of the first capacitor C1 is connected to the first end of the second capacitor C2, and the common end of the connection is connected to the second end of the secondary coil, the anode of the sixth diode D6 is connected to the second end of the second capacitor C2, and the common end of the connection is connected to the negative power supply electrode of the load;

[0070] The resonant inductor Lr and the rectifier diode circuit are used to convert alternating current into direct current, and the resonant inductor Lr and the resonant capacitor circuit are used to form a resonant body.

[0071] The resonant inductor Lr can be an independent inductor or integrated into the transformer TR1. The transformer TR2 can detect the secondary current isec(t) of the transformer TR1. The turns ratio of TR2 is N1 / N5=n1, N1 / N7=n3, and the relationship between isec(t) and the transformer current ics(t) is ics(t)=n1×isec(t). The turns ratio of TR1 is N3 / N4=n2, and the primary current of the transformer TR1 is ipri(t). Assuming that the excitation inductance Lm of TR1 is infinite, the relationship between ipri(t) and ics(t) is: ics(t)=n2×n1×isec(t).

[0072] In some embodiments, the soft switch control module 3 includes a transformer TR2, a seventh diode D7, a first integration module, a first reset switch Qreset, a first comparator CMP1, a second comparator CMP2, an inverter NOT1 and a first AND gate AND1;

[0073] The first end of the primary coil of the mutual inductor TR2 is connected to the second end of the secondary coil of the transformer TR1, the second end of the primary coil of the mutual inductor TR2 is connected to the rectifier module 2, the first end of the first secondary coil of the mutual inductor TR2 is connected to the anode of the seventh diode D7, the cathode of the seventh diode D7 is connected to the input end of the first integration module, the output end of the first integration module is connected to the first end of the first reset switch Qreset and the inverting input end of the first comparator CMP1, the non-inverting input end of the first comparator CMP1 is connected to the first reference voltage, and the output end of the first comparator CMP1 is connected to the first input end of the first AND gate AND1 , the second end of the first reset switch Qreset is connected to the second end of the first secondary coil and the common end of the connections is grounded, the non-inverting input end and the inverting input end of the second comparator CMP2 are both connected to the second reference voltage, the first end of the second secondary coil of the mutual inductor TR2 is also connected to the inverting input end of the second comparator CMP2, the output end of the second comparator CMP2 is respectively connected to the reset end of the first reset switch Qreset and the input end of the inverter NOT1, the output end of the inverter NOT1 is connected to the second input end of the first AND gate AND1, and the output signal of the first AND gate AND1 is used as the turn-on signal of the upper bridge arm of the lagging bridge arm;

[0074] The controller 4 is specifically used for controlling the conduction and shutoff of the two controllable switches of the leading bridge arm in the conduction period of the full-bridge inverter circuit 1, controlling the controllable switch of the upper bridge arm of the lagging bridge arm based on the conduction signal of the upper bridge arm of the lagging bridge arm, and controlling the controllable switch of the lower bridge arm of the lagging bridge arm based on the reverse signal of the conduction signal of the upper bridge arm of the lagging bridge arm;

[0075] The seventh diode D7 is used for reverse protection, the first integration module is used to integrate the current to obtain the voltage, the first reset switch Qreset is used to be turned on when the voltage of the second secondary coil is lower than the second reference voltage, the first comparator CMP1 is used to compare the voltage of the first secondary coil with the first reference voltage, and the second comparator CMP2 is used to compare the voltage of the second secondary coil with the second reference voltage.

[0076] Taking the positive half cycle as an example, the transformer TR2 has a turn ratio of N1 / N5=N1 / N6=n1, N1 / N7=n3, and the capacitance of the integrating capacitor cs is equal to that of cs1, which is Ccs. According to the loop theorem, ics(t)=n1isec(t), and the integrating capacitor cs integrates ics(t) in real time, and the integration result is vcs(t): .

[0077] When the integrated voltage Vcs(t) is not greater than the first reference voltage Vref, the first comparator CMP1 outputs a high level. When the voltage Vz(t) is greater than the second reference voltage, the second comparator CMP2 outputs a low level, which is output to the first AND gate AND1 through the inverter NOT1. At this time, the first AND gate AND1 outputs a high level, and the low level output by the second comparator CMP2 cannot control the first reset switch Qreset to turn on.

[0078] When the integrated voltage Vcs(t) is greater than the first reference voltage Vref, the first comparator CMP1 outputs a low level. When the voltage Vz(t) is less than the second reference voltage, the second comparator CMP2 outputs a high level, which is output to the first AND gate AND1 through the inverter NOT1. At this time, the first AND gate AND1 outputs a low level, and the high level output by the second comparator CMP2 controls the first reset switch Qreset to turn on.

[0079] When the integrated voltage Vcs(t) is greater than the first reference voltage Vref, the first comparator CMP1 outputs a low level, and at this time, the first AND gate AND1 outputs a low level.

[0080] After the control signal of Q4 is determined, Q3 is controlled to be turned on or off according to the principle of complementarity. At this time, the conduction or shutoff of Q3 is controlled by software logic.

[0081] The first integration module is composed of Rs and Cs. PWM_Qreset is a control signal of the first reset switch.

[0082] In some embodiments, the soft switch control module 3 further includes an eighth diode D8, a second integration module, a second reset switch Qreset1, a third comparator CMP3 and a second AND gate AND2;

[0083] An anode of the eighth diode D8 is connected to a first end of the third secondary coil of the mutual inductor TR2, a second end of the third secondary coil of the mutual inductor TR2 is grounded, a cathode of the eighth diode D8 is connected to an input end of the second integration module, an output end of the second integration module is connected to a first end of the second reset switch Qreset1 and an inverting input end of the third comparator CMP3, a second end of the second reset switch Qreset1 is grounded, a non-inverting input end of the third comparator CMP3 is connected to a first reference voltage, an output end of the third comparator CMP3 is connected to a first input end of the second AND gate AND2, an output end of the second comparator CMP2 is connected to a second input end of the second AND gate AND2, and an output signal of the second AND gate AND2 is used as a turn-on signal of the lower bridge arm of the lagging bridge arm;

[0084] The eighth diode D8 is used for reverse protection, the second integration module is used for integrating the current to obtain the voltage, the second reset switch Qreset1 is used for being turned on when the voltage of the second secondary coil is higher than the second reference voltage, and the third comparator CMP3 is used for comparing the voltage on the second secondary coil with the first reference voltage.

[0085] The controller 4 is specifically used to control the conduction and shutdown of the two controllable switches of the leading bridge arm according to the conduction period of the full-bridge inverter circuit 1, to control the controllable switch of the upper bridge arm of the lagging bridge arm based on the conduction signal of the upper bridge arm of the lagging bridge arm, and to control the controllable switch of the lower bridge arm of the lagging bridge arm based on the conduction signal of the lower bridge arm of the lagging bridge arm.

[0086] The second integration module is composed of Rs1 and Cs1. PWM_Qreset1 is the control signal of the second reset switch.

[0087] Furthermore, in order to realize hardware control, in the negative half cycle, when the integrated voltage Vcs1(t) is not greater than the first reference voltage Vref, the third comparator CMP3 outputs a high level, and when the voltage Vz(t) is not greater than the second reference voltage, the second comparator CMP2 outputs a high level, and at this time the second AND gate AND2 outputs a high level.

[0088] When the integrated voltage Vcs1(t) is not greater than the first reference voltage Vref, the third comparator CMP3 outputs a high level. When the voltage Vz(t) is less than the second reference voltage, the second comparator CMP2 outputs a high level. At this time, the second AND gate AND2 outputs a high level, and the inverter NOT1 outputs a low level, which cannot control the second reset switch Qreset1 to turn on.

[0089] When the integrated voltage Vcs1 (t) is greater than the first reference voltage Vref, the third comparator CMP3 outputs a low level, and at this time, the second AND gate AND2 outputs a low level.

[0090] It should be noted that both the first reset switch Qreset and the second reset switch Qreset1 are high-level conduction switches, which pull Vcs1(t) to the ground when they are turned on.

[0091] Figure 3 A numerical schematic diagram of device voltage in a control device for a full-bridge inverter circuit soft switch provided by the present invention; Figure 4 A numerical schematic diagram of device voltages in another full-bridge inverter circuit soft switch control device provided by the present invention;

[0092] Among them, ics(t): the output current of diode D7 during the positive half switching cycle; VDD / 2: half of the power supply voltage of the system main control chip; vz(t): the "-" input signal of comparator CMP2; CMP2_OUT:: the output of comparator CMP2; PWM_Qreset: the control signal of Qreset; Vref: the target value of Vcs(t) and Vcs1(t) at time tx, used to realize the soft switching control of Q3 and Q4; Vcs(t): the terminal voltage of the positive half cycle of the integral capacitor cs; Vcs1(t): the terminal voltage of the negative half cycle of the integral capacitor cs1; CMP1_OUT:: the output of comparator CMP1; PWM_Q4: the output of AND gate AND1, the control signal of Q4; PWM_Q1: the control signal of Q1; PWM_Q2: the control signal of Q2; t DT : Dead time of the upper and lower switches of the lagging bridge arm; Tps: Phase shift value of the leading bridge arm and the lagging bridge arm; Ts: Switching period; D1: The proportion of Tps to the switching period Ts; ics1(t): Output current of diode D8; iz(t): Current of the secondary winding N7 of the transformer TR2.

[0093] Figure 5 A flowchart of a full-bridge inverter circuit soft switch control method provided by the present invention, the full-bridge inverter circuit soft switch control method is applied to a controller in a full-bridge inverter circuit soft switch control device, comprising:

[0094] S11: obtaining the power of the direct current of the full-bridge inverter circuit input to the control device of the full-bridge inverter circuit soft switch;

[0095] S12: determining a phase shift value between a leading bridge arm and a lagging bridge arm of a full-bridge inverter circuit according to the power;

[0096] S13: Determine the dead time of conduction of the controllable switch of the upper bridge arm and the controllable switch of the lower bridge arm of the lagging bridge arm according to the phase shift value;

[0097] S14: determining a first reference voltage and a second reference voltage according to the dead time and outputting the voltages to a soft switch control module in a control device for a soft switch of a full-bridge inverter circuit;

[0098] S15: Determine whether the two controllable switches of the leading bridge arm are turned on and off according to the phase shift value, and control the two controllable switches of the lagging bridge arm to be turned on and off based on the on signal of the lagging bridge arm output by the soft switch control module.

[0099] The main control strategies of the controller are as follows:

[0100] Dynamic control obtains the period Ts;

[0101] Sampling Vo and Io to calculate po, or calculating input power by detecting Vi and Ii, and then calculating the transmission efficiency Convert to get po.

[0102] Press T ps =f1×f4(f2×f3) calculate Tps;

[0103] According to D1=T ps / T s Formula to calculate D1;

[0104] Press t DT =f5×f6[(f 18 +f7×f 11 +f8) / f 13 ]+f9×f 10 [(f 18 + f 16 ) / f 13 ]-f 12 ; Calculate t DT ;

[0105] Press V ref =f 19 ×(f 21 +f 22 -f 20 )(f 24 -1)+f 19 ×f 20 ×(f 25 -1) to calculate Vref;

[0106] Use the "PWM_Q4" signal to control Q4, and the "PWM_Q3" signal to control Q3;

[0107] Will be used to generate PWM_Q1 and PWM_Q2 signals to control Q1 and Q2 of the leading bridge arm.

[0108] In some embodiments, determining the phase shift value between the leading bridge arm and the lagging bridge arm of the full-bridge inverter circuit according to the power includes:

[0109] According to the power determination relationship and the power determination full-bridge inverter circuit leading bridge arm and lagging bridge arm phase shift value, the power determination relationship is T ps =f1×f4(f2×f3);

[0110] Among them, f1 is the first function, and the function value is related to the inductance value L of the resonant inductance of the secondary side of the transformer. r And the capacitance value C of the resonant capacitor circuit of the filter module r is positively correlated, f2 is the second function, and the function value is positively correlated with V o / (n2×Vi ) and (n2×V o ×V i ) are negatively correlated with the DC power p o And the conduction period T of the full-bridge inverter circuit s Both are positively correlated, V o is the output voltage to the load, V i is the input DC voltage, n2 is the turns ratio of the primary coil to the secondary coil of the transformer, f3 is the third function, and the function value is related to L r and C r Both were negatively correlated with T s There is a positive correlation, and f4 is the fourth function.

[0111] In some embodiments, determining the dead time of the controllable switch of the upper bridge arm and the controllable switch of the lower bridge arm of the lagging bridge arm according to the phase shift value includes:

[0112] The dead time of the controllable switch of the upper bridge arm and the controllable switch of the lower bridge arm of the lagging bridge arm is determined according to the phase shift value and the phase shift value relationship. The phase shift value relationship is t DT =f5×f6[(f 18 +f7×f 11 +f8) / f 13 ]+f9×f 10 [(f 18 +f 16 ) / f 13 ]-f 12 ;

[0113] Among them, f5 is the fifth function, and the function value is related to L r and C r There is a positive correlation, f6 is the sixth function, f7 is the seventh function, and the function value is related to C r 、n2、V i and V o There is a positive correlation, f8 is the eighth function, and the function value is related to C r 、n2、V i and V o Negatively correlated, f9 is the ninth function, and the function value is related to L r and C r Negatively correlated, f 10 is the tenth function, f 11 is the eleventh function, , f 12 is the twelfth function, and T s Negatively correlated, f 13 is the thirteenth function, , f 14 is the fourteenth function, and its value is related to p o and T sNegatively correlated, f 15 is the fifteenth function, , f 16 is the sixteenth function, and its value is related to C ds 、n2、V i and V o Positively correlated with C r and C cs Negatively correlated, C cs is the capacitance value of the integral capacitor in the soft switch control module, f 17 is the seventeenth function, and its value is related to C r 、V o Positively correlated, f 18 is the eighteenth function, f 18 =f 17 +f 14 .

[0114] Assume that Q4 is turned off at time tx, and define the dead time as t DT =t1-tx. During the time from tx to t1, ipri(t) gradually decreases from ipri(tx) to 0. Before ipri(t1)=0, turning off Q4 and turning on Q3 is the zero voltage switching of Q3 and Q4.

[0115] In some embodiments, a soft switch control module in a control device for a soft switch of a full-bridge inverter circuit that determines a first reference voltage and a second reference voltage according to a dead time and outputs the voltage to the soft switch includes:

[0116] The first reference voltage is determined according to the dead time and the first reference voltage relationship, where the first reference voltage relationship is V ref =f 19 ×(f 21 +f 22 -f 20 )(f 24 -1)+f 19 ×f 20 ×(f 25 -1);

[0117] Among them, V ref is the first reference voltage, f 19 is the nineteenth function, and its value is related to C r and n1 are positively correlated with C cs Negatively correlated, f 20 is the twentieth function, f 20 =n2V i , f 21 is the twenty-first function, and its value is related to V o Positively correlated, f 22 is the twenty-second function, and its value is related to po and T s Positively correlated with C r and V o Negatively correlated, f 23 is the twenty-third function, and its value is related to L r and C r Negatively correlated, f 24 is the twenty-fourth function, f 24 =cos{f 23 ×[(1-2D1)T s +t DT ]},f 25 is the twenty-fifth function, f 25 =cos{f 23 ×[(1-2D1)T s ]}, D1 is the duty cycle, D1=T ps / T s , T s is the conduction period of the full-bridge inverter circuit;

[0118] The second reference voltage is determined according to its own power supply voltage, and the expression of the second reference voltage is VDD / 2, wherein VDD is its own power supply voltage.

[0119] It should also be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0120] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0121] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control device for a full-bridge inverter circuit soft switch, characterized in that: include: A full-bridge inverter circuit, the full-bridge inverter circuit comprising a leading bridge arm and a lagging bridge arm, the control ends of the two controllable switches on the leading bridge arm and the control ends of the two controllable switches on the lagging bridge arm are both connected to the output end of the controller, the DC input end of the full-bridge inverter circuit is connected to a DC power supply, and the AC output end is connected to the primary side of the transformer, and is used for converting the DC power input from the DC input end into AC power and outputting it to the transformer based on the control of the controller; The transformer, the secondary side of which is connected to the input end of the rectifier module and the input end of the controller respectively, is used to boost the AC power output by the full-bridge inverter circuit and then output it to the rectifier module; The rectifier module, whose output end is connected to a DC load, is used to convert the AC power boosted by the transformer into DC power and output it to the DC load; A soft switch control module, wherein a first end of the soft switch control module is connected to the secondary side of the transformer, and a second end of the soft switch control module is connected to the input end of the controller, and is used to generate a conduction signal of the lagging bridge arm based on the power input by the DC power supply and the transformation multiple of the transformer; The controller is used to control the on and off of the two controllable switches of the leading bridge arm according to the conduction period of the full-bridge inverter circuit, and controls the on and off of the two controllable switches of the lagging bridge arm based on the conduction signal of the lagging bridge arm, wherein the controllable switch of the lower bridge arm of the lagging bridge arm is turned on later than the controllable switch of the upper bridge arm of the leading bridge arm, and the controllable switch of the upper bridge arm of the lagging bridge arm is turned on later than the controllable switch of the lower bridge arm of the leading bridge arm.

2. The control device for soft switching of a full-bridge inverter circuit according to claim 1, characterized in that: The full-bridge inverter circuit includes a first controllable switch, a second controllable switch, a third controllable switch and a fourth controllable switch; The first controllable switch is arranged on the lower bridge arm of the leading bridge arm, the second controllable switch is arranged on the upper bridge arm of the leading bridge arm, the third controllable switch is arranged on the lower bridge arm of the lagging bridge arm, and the fourth controllable switch is arranged on the upper bridge arm of the lagging bridge arm; The output positive electrode of the DC power supply is respectively connected to the first end of the second controllable switch and the first end of the fourth controllable switch; the common end to which the second end of the second controllable switch is connected to the first end of the first controllable switch is connected as the first output end of the full-bridge inverter circuit and the first end of the primary coil of the transformer; the second end of the fourth controllable switch is connected to the first end of the third controllable switch and the common end connected is connected to the second end of the primary coil of the transformer as the second output end of the full-bridge inverter circuit; the second end of the first controllable switch and the second end of the third controllable switch are both connected to the output negative electrode of the DC power supply; and the control ends of the first controllable switch, the second controllable switch, the third controllable switch and the fourth controllable switch are all connected to the controller for being turned on or off based on the control of the controller.

3. The control device for soft switching of a full-bridge inverter circuit according to claim 1, characterized in that: The first controllable switch includes a first transistor, a first diode and a first parasitic capacitor, the second controllable switch includes a second transistor, a second diode and a second parasitic capacitor, the third controllable switch includes a third transistor, a third diode and a third parasitic capacitor, and the fourth controllable switch includes a fourth transistor, a fourth diode and a fourth parasitic capacitor; A cathode of the first diode is connected to a first end of the first transistor and a first end of the first parasitic capacitor, an anode of the first diode is connected to a second end of the first transistor and a second end of the first parasitic capacitor, a cathode of the second diode is connected to a first end of the second transistor and a first end of the second parasitic capacitor, an anode of the second diode is connected to a second end of the second transistor and a second end of the second parasitic capacitor, a cathode of the third diode is connected to a first end of the third transistor and a first end of the third parasitic capacitor, an anode of the third diode is connected to a second end of the third transistor and a second end of the third parasitic capacitor, a cathode of the fourth diode is connected to a first end of the fourth transistor and a first end of the fourth parasitic capacitor, and an anode of the fourth diode is connected to a second end of the fourth transistor and a second end of the fourth parasitic capacitor.

4. The control device for soft switching of a full-bridge inverter circuit according to claim 1, characterized in that: The rectifier module includes a resonant inductor, a rectifier diode circuit and a resonant capacitor circuit, the rectifier diode circuit includes a fifth diode and a sixth diode, and the resonant capacitor circuit includes a first capacitor and a second capacitor; The first end of the resonant inductor is connected to the first end of the secondary coil of the transformer, and the common end of the connection is connected to the positive power supply electrode of the load, the second end of the resonant inductor is connected to the anode of the fifth diode and the cathode of the sixth diode, the cathode of the fifth diode is connected to the first end of the first capacitor, the second end of the first capacitor is connected to the first end of the second capacitor, and the common end of the connection is connected to the second end of the secondary coil, the anode of the sixth diode is connected to the second end of the second capacitor, and the common end of the connection is connected to the negative power supply electrode of the load; The resonant inductor and the rectifier diode circuit are used to convert alternating current into direct current, and the resonant inductor and the resonant capacitor circuit are used to form a resonant body.

5. The control device for soft switching of a full-bridge inverter circuit according to any one of claims 1 to 4, characterized in that: The soft switch control module includes a mutual inductor, a seventh diode, a first integration module, a first reset switch, a first comparator, a second comparator, an inverter and a first AND gate; The first end of the primary coil of the mutual inductor is connected to the second end of the secondary coil of the transformer, the second end of the primary coil of the mutual inductor is connected to the rectifier module, the first end of the first secondary coil of the mutual inductor is connected to the anode of the seventh diode, the cathode of the seventh diode is connected to the input end of the first integration module, the output end of the first integration module is connected to the first end of the first reset switch and the inverting input end of the first comparator, the positive input end of the first comparator is connected to the first reference voltage, the output end of the first comparator is connected to the first input end of the first AND gate, the second end of the first reset switch is connected to the second end of the first secondary coil and the common end of the connections is grounded, the positive input end and the inverting input end of the second comparator are both connected to the second reference voltage, the first end of the second secondary coil of the mutual inductor is also connected to the inverting input end of the second comparator, the output end of the second comparator is respectively connected to the reset end of the first reset switch and the input end of the inverter, the output end of the inverter is connected to the second input end of the first AND gate, and the output signal of the first AND gate is used as the conduction signal of the upper bridge arm of the lagging bridge arm; The controller is specifically used to control the on-cycle of the full-bridge inverter circuit to turn on and off the two controllable switches of the leading bridge arm, control the controllable switch of the upper bridge arm of the lagging bridge arm based on the on-signal of the upper bridge arm of the lagging bridge arm, and control the controllable switch of the lower bridge arm of the lagging bridge arm based on the reverse signal of the on-signal of the upper bridge arm of the lagging bridge arm; The seventh diode is used for reverse protection, the first integration module is used for integrating the current to obtain the voltage, the first reset switch is used for turning on when the voltage of the second secondary coil is lower than the second reference voltage, the first comparator is used for comparing the voltage of the first secondary coil with the first reference voltage, and the second comparator is used for comparing the voltage of the second secondary coil with the second reference voltage.

6. The control device for soft switching of a full-bridge inverter circuit according to claim 5, characterized in that: The soft switch control module also includes an eighth diode, a second integration module, a second reset switch, a third comparator and a second AND gate; The anode of the eighth diode is connected to the first end of the third secondary coil of the mutual inductor, the second end of the third secondary coil of the mutual inductor is grounded, the cathode of the eighth diode is connected to the input end of the second integration module, the output end of the second integration module is connected to the first end of the second reset switch and the inverting input end of the third comparator, the second end of the second reset switch is grounded, the non-inverting input end of the third comparator is connected to the first reference voltage, the output end of the third comparator is connected to the first input end of the second AND gate, the output end of the second comparator is connected to the second input end of the second AND gate, and the output signal of the second AND gate is used as the turn-on signal of the lower bridge arm of the lagging bridge arm; The eighth diode is used for reverse protection, the second integration module is used for integrating the current to obtain the voltage, the second reset switch is used for turning on when the voltage of the second secondary coil is higher than the second reference voltage, and the third comparator is used for comparing the voltage on the second secondary coil with the first reference voltage. The controller is specifically used to control the conduction and disconnection of the two controllable switches of the leading bridge arm according to the conduction period of the full-bridge inverter circuit, control the controllable switch of the upper bridge arm of the lagging bridge arm based on the conduction signal of the upper bridge arm of the lagging bridge arm, and control the controllable switch of the lower bridge arm of the lagging bridge arm based on the conduction signal of the lower bridge arm of the lagging bridge arm.

7. A method for controlling a soft switch of a full-bridge inverter circuit, characterized in that: The controller used in the control device of the full-bridge inverter circuit soft switch includes: Acquiring the power of the direct current of the full-bridge inverter circuit input into the control device of the full-bridge inverter circuit soft switch; Determine a phase shift value between an advanced bridge arm and a lagging bridge arm of the full-bridge inverter circuit according to the power; Determine the dead time of the controllable switch of the upper bridge arm and the controllable switch of the lower bridge arm of the lagging bridge arm being turned on according to the phase shift value; A soft switch control module in a control device for a soft switch of a full-bridge inverter circuit determines a first reference voltage and a second reference voltage according to the dead time and outputs the voltages to the soft switch; The two controllable switches of the leading bridge arm are turned on and off according to the phase shift value, and the two controllable switches of the lagging bridge arm are controlled to be turned on and off based on the turn-on signal of the lagging bridge arm output by the soft switch control module.

8. The method for controlling a soft switch of a full-bridge inverter circuit according to claim 7, characterized in that: Determining a phase shift value between a leading bridge arm and a lagging bridge arm of the full-bridge inverter circuit according to the power includes: The phase shift value between the leading bridge arm and the lagging bridge arm of the full-bridge inverter circuit is determined according to the power determination relationship and the power, and the power determination relationship is T ps =f1×f4(f2×f3); Among them, f1 is the first function, and the function value is related to the inductance value L of the resonant inductance of the secondary side of the transformer. r And the capacitance value C of the resonant capacitor circuit of the filter module r is positively correlated, f2 is the second function, and the function value is positively correlated with V o / (n2×V i ) and (n2×V o ×V i ) are negatively correlated with the DC power p o and the conduction period T of the full-bridge inverter circuit s Both are positively correlated, V o is the output voltage to the load, V i is the input DC voltage, n2 is the turns ratio of the primary coil to the secondary coil of the transformer, f3 is the third function, and the function value is related to L r and C r Both were negatively correlated with T s There is a positive correlation, and f4 is the fourth function.

9. The method for controlling a soft switch of a full-bridge inverter circuit according to claim 8, characterized in that: Determining the dead time of the controllable switch of the upper bridge arm and the controllable switch of the lower bridge arm of the lagging bridge arm according to the phase shift value includes: The dead time of the controllable switch of the upper bridge arm and the controllable switch of the lower bridge arm of the lagging bridge arm is determined according to the phase shift value and the phase shift value relationship, and the phase shift value relationship is t DT =f5×f6[(f 18 +f7×f 11 +f8) / f 13 ]+f9×f 10 [(f 18 + f 16 ) / f 13 ]-f 12 ; Among them, f5 is the fifth function, and the function value is related to L r and C r There is a positive correlation, f6 is the sixth function, f7 is the seventh function, and the function value is related to C r 、n2、V i and V o There is a positive correlation, f8 is the eighth function, and the function value is related to C r 、n2、V i and V o Negatively correlated, f9 is the ninth function, and the function value is related to L r and C r Negatively correlated, f 10 is the tenth function, f 11 is the eleventh function, , f 12 is the twelfth function, and T s Negatively correlated, f 13 is the thirteenth function, , f 14 is the fourteenth function, and its value is related to p o and T s Negatively correlated, f 15 is the fifteenth function, , f 16 is the sixteenth function, and its value is related to C ds 、n2、V i and V o Positively correlated with C r and C cs Negatively correlated, C cs is the capacitance value of the integral capacitor in the soft switch control module, f 17 is the seventeenth function, and its value is related to C r 、V o Positively correlated, f 18 is the eighteenth function, f 18 =f 17 +f 14 .

10. The method for controlling a soft switch of a full-bridge inverter circuit according to claim 7, characterized in that: The soft switch control module in the control device for the soft switch of the full-bridge inverter circuit determines the first reference voltage and the second reference voltage according to the dead time and outputs them to the control device comprises: The first reference voltage is determined according to the dead time and a first reference voltage relationship, wherein the first reference voltage relationship is V ref =f 19 ×(f 21 +f 22 -f 20 )(f 24 -1)+f 19 ×f 20 ×(f 25 -1); Among them, V ref is the first reference voltage, f 19 is the nineteenth function, and its value is related to C r and n1 are positively correlated with C cs Negatively correlated, f 20 is the twentieth function, f 20 =n2V i , f 21 is the twenty-first function, and its value is related to V o Positively correlated, f 22 is the twenty-second function, and its value is related to p o and T s Positively correlated with C r and V o Negatively correlated, f 23 is the twenty-third function, and its value is related to L r and C r Negatively correlated, f 24 is the twenty-fourth function, f 24 =cos{f 23 ×[(1-2D1)T s +t DT ]},f 25 is the twenty-fifth function, f 25 =cos{f 23 ×[(1-2D1)T s ]}, D1 is the duty cycle, D1=T ps / T s , T s is the conduction period of the full-bridge inverter circuit; The second reference voltage is determined according to its own power supply voltage, and the expression of the second reference voltage is VDD / 2, wherein VDD is its own power supply voltage.

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