Boost and buck bidirectional inverter circuit

Abstract

A boost and buck bidirectional inverter circuit can realize wide-range conversion from direct current to alternating current, can complete bidirectional maximum power input and stable output during bidirectional conversion of alternating current and direct current, and comprises a first power supply, a bidirectional voltage stabilization module, a resonant conversion module, a bidirectional inverter module and a second power supply, the first power supply is connected with a first end of the bidirectional voltage stabilization module, a second end of the bidirectional voltage stabilization module is connected with a first end of the resonant conversion module, a second end of the resonant conversion module is connected with a first end of the bidirectional inversion module, and a second end of the bidirectional inversion module is connected with the second power supply; the control module comprises an acquisition unit and a driving unit, and the acquisition unit is used for acquiring voltage signals of the bidirectional voltage stabilization module, the resonant conversion module and the bidirectional inversion module; the driving unit is used for providing control signals for the voltage stabilizing module, the resonant conversion module and the bidirectional inversion module according to the collected voltage signals.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic circuits, and particularly relates to a boost - buck bidirectional inverter circuit. Background Art

[0002] A bidirectional inverter is a power conversion device that can convert direct current (DC) electrical energy into alternating current (AC) electrical energy, and at the same time can also convert AC electrical energy into DC electrical energy, playing an important role in many applications, such as energy storage systems, electric vehicle charging and discharging, solar panel systems, etc.

[0003] The bidirectional inverter mainly includes an inverter for converting DC to AC and a converter for converting AC to DC, which is realized by controlling switches (IGBT, silicon - based MOSFET or SiC switching devices); however, the applicant has found in actual production that the current bidirectional inverter circuit has defects that limit its applicability and performance, mainly in the following aspects:

[0004] 1. Due to the characteristics of its own circuit structure, it can usually only perform boost and inversion operations on DC input within a narrow voltage range. This results in that in a wide voltage range, such as when the input voltage is too low or too high, the inverter cannot work properly. Especially after the input voltage is stepped - down by a fixed transformer ratio, the voltage of the high - voltage bus may not meet the requirements of the inverter, thus affecting the normal operation of the inverter;

[0005] 2. It can only output a relatively narrow range of DC voltage through mains rectification, which limits its applicability to a wide range of DC voltage - type loads. In practical applications, in many cases, it is necessary to cope with loads of various DC voltage types. Limited by the current technology, the existing bidirectional inverters are difficult to perform this task; Summary of the Utility Model

[0006] I. Technical Problems to be Solved

[0007] Aiming at the deficiencies of the prior art, the utility model provides a boost - buck bidirectional inverter circuit, which can achieve wide - range DC - to - AC conversion, and can complete bidirectional maximum - power input and stable output when performing bidirectional conversion between AC and DC.

[0008] II. Specific Technical Solutions

[0009] A boost - buck bidirectional inverter circuit includes an electrically - connected first power source, a bidirectional voltage - stabilizing module, a resonant conversion module, a bidirectional inverter module, and a second power source; the first power source is connected to the first end of the bidirectional voltage - stabilizing module, the second end of the bidirectional voltage - stabilizing module is connected to the first end of the resonant conversion module, the second end of the resonant conversion module is connected to the first end of the bidirectional inverter module, and the second end of the bidirectional inverter module is connected to the second power source;

[0010] The bidirectional voltage stabilizing module is used to receive the DC input at the first end of the first power supply or the resonance conversion module, and output a set DC output; the resonance conversion module is used to receive the DC input at the second end of the bidirectional voltage stabilizing module or the first end of the bidirectional inverter module, and step up or step down the DC input; the bidirectional inverter module is used to receive the DC input at the second end of the resonance conversion module or the AC input of the second power supply, and convert the DC input into an AC output or convert the AC input into a DC output;

[0011] It further includes a control module and an auxiliary power supply module. The control module includes an acquisition unit and a driving unit which are electrically connected. The acquisition unit and the driving unit are respectively connected to the bidirectional voltage stabilizing module, the resonance conversion module and the bidirectional inverter module through wires. The driving unit is used to control the voltage stabilizing module, the resonance conversion module and the bidirectional inverter module according to the electrical signals provided by the acquisition unit; the output end of the auxiliary power supply module is respectively connected to the bidirectional voltage stabilizing module, the resonance conversion module and the bidirectional inverter module through wires;

[0012] An anti-reverse connection module is also arranged between the first power supply and the bidirectional voltage stabilizing module. The anti-reverse connection module includes a resistor R1. One end of the resistor R1 has a first branch connected to the positive pole J1 of the first power supply, and a second branch connected to the bidirectional voltage stabilizing module; the other end of the resistor R1 has a first branch connected to the G pole of the MOS transistor Q17, and a second branch connected to the negative pole of the voltage stabilizing diode D1; the D pole of the MOS transistor Q17 is connected to the negative pole J4 of the first power supply, and the first branch of the S pole of the MOS transistor Q17 is connected to the positive pole of the voltage stabilizing diode D1; the negative pole of the voltage stabilizing diode is grounded through a resistor R4 with the G pole of the MOS transistor Q17.

[0013] Implementation principle, working principle:

[0014] For the inverter circuit of this solution, the functions achieved are different according to different input types;

[0015] When the first power supply is a DC input and the second power supply is an AC output, the inverter function is achieved. The implementation principle is that the acquisition unit of the control module first real-time collects the voltage value of the DC input, and then the driving unit of the control module drives the bidirectional voltage stabilizing module to raise or lower the DC input to a set voltage for stable output; in this step, through the voltage regulation of the voltage stabilizing module for the DC input, a wider range of DC inputs can be adapted; among them, the anti-reverse connection module arranged at the first power supply can well avoid the damage of the first power supply caused by current backflow, which is safer; a MOS transistor is selected as the core component of the anti-reverse connection module. When the input power supply is reversely connected, the MOS transistor is not conducting, the current has no loop and will not burn out. At the same time, the resistance of the MOS transistor is very small, the power consumption is small, and the heat generation is also small;

[0016] When the stable DC input enters the resonant conversion module, under the action of the resonant conversion module, the voltage and current of the DC input oscillate periodically, directly increasing the voltage of the DC input. At this time, the drive unit can adjust the drive signal according to the parameters of the DC input collected in real time, ensuring that the DC input is stably increased according to the installation settings, with stronger adaptability and greater stability;

[0017] The bidirectional inverter module converts the increased DC input into the second power supply terminal with high-voltage AC output. During the AC conversion, the drive unit controls each component according to the voltage and current signals collected by the acquisition unit in the bidirectional inverter module, can be applied to a wider range of DC inputs, and can ensure the power stability of the DC input and AC output.

[0018] When the second power supply is AC voltage input, the bidirectional inverter module converts the input high-voltage alternating current into high-voltage direct current, and the resonant conversion module then performs resonant step-down on the high-voltage direct current and converts it into low-voltage direct current. Finally, the bidirectional voltage regulator module converts the converted low-voltage direct current into stable low-voltage DC output to achieve inversion; during the process of inverting alternating current into direct current, the drive unit adjusts the drive signal in real time according to the voltage signal collected by the acquisition unit, and then adjusts the operation of each module, can be adapted to a wider range of AC input voltages, and can maintain the input power.

[0019] Preferably, the auxiliary power supply module includes auxiliary power supplies U1 and U19. The auxiliary power supply U1 includes an input terminal, a first output terminal, a second output terminal, a third output terminal, and a fourth output terminal; the positive pole J1 of the first power supply is connected to the positive pole of the input terminal of the auxiliary power supply U1 through a diode D2, and the first branch of the negative pole of the diode D2 is connected to the positive pole of the input terminal of the auxiliary power supply U1; the negative pole of the input terminal of the auxiliary power supply U1 is connected to the first branch of the negative pole J4 of the first power supply; the positive pole of the input terminal of the auxiliary power supply U19 is connected to the second branch of the negative pole of the diode D2, and the negative pole of the input terminal of the auxiliary power supply U19 is connected to the second branch of the negative pole J1 of the first power supply terminal.

[0020] Preferably, the bidirectional voltage regulator module includes a polarized capacitor C6 and a non-polarized capacitor C9. The polarized capacitor C6 and the non-polarized capacitor C9 are connected across the positive and negative poles of the first power supply, and the positive pole of the polarized capacitor C6 is connected to the positive pole J1 of the first power supply;

[0021] The bidirectional voltage stabilizing module further includes half-bridge drivers U2 and U3. The power input ends of the half-bridge drivers U2 and U3 are connected in parallel and then connected to the first output end of the auxiliary power supply. The signal input ends of the half-bridge drivers U2 and U3 are respectively connected to the driving unit. The first output end of the half-bridge driver U2 is connected to the G pole of the MOS transistor Q1, and the second output end of the half-bridge driver U2 is connected to the G pole of Q9. The first output end of the half-bridge driver U3 is connected to the G pole of the MOS transistor Q2, and the second output end of the half-bridge driver U3 is connected to the G pole of the MOS transistor Q10.

[0022] The D pole of the MOS transistor Q1 is connected to the second branch on the first power supply side through the resistor R1. The first branch of the S pole of the MOS transistor Q1 is connected to the D pole of the MOS transistor Q9. The first branch of the S pole of the MOS transistor Q9 is connected to the second branch of the S pole of the MOS transistor Q17 through the resistor R5. The second branch of the S pole of the MOS transistor Q9 is connected to the first branch of the S pole of the MOS transistor Q10. The first branch of the D pole of the MOS transistor Q10 is connected to the S pole of the MOS transistor Q2, and the second branch of the D pole of the MOS transistor Q10 is connected to the second branch of the S pole of the MOS transistor Q1 through the inductor L2.

[0023] The bidirectional voltage stabilizing module further includes a polarized capacitor C7 and a non-polarized capacitor C8. The polarized capacitor C7 and the non-polarized capacitor C8 are connected across the D pole of the MOS transistor Q2 and the second branch of the S pole of the MOS transistor Q10. The D pole of the MOS transistor Q2 and the second branch of the S pole of the MOS transistor Q10 are also used to be connected to the first end of the resonant conversion module.

[0024] The acquisition unit includes an acquisition sub-unit U11, an acquisition sub-unit U12, and an acquisition sub-unit U15. The acquisition sub-unit U11 is used to acquire the voltage across the capacitor C9, the acquisition sub-unit U12 is used to acquire the voltage across the capacitor C8, and the acquisition sub-unit U15 is used to acquire the voltage across the resistor R5.

[0025] Preferably, the resonant conversion module includes half-bridge drivers U4, U5, U6, and U7 whose signal input ends are connected to the driving unit. Among them, the power input ends of the half-bridge drivers U4 and U5 are connected to the second output end of the auxiliary power supply U1. The power input ends of the half-bridge drivers U6 and U7 are connected to the third output end of the auxiliary power supply U1.

[0026] The first output terminal of the half-bridge driver U4 is connected to the G pole of the MOS transistor Q3, and the second output terminal of the half-bridge driver U4 is connected to the G pole of Q11; the first output terminal of the half-bridge driver U5 is connected to the G pole of the MOS transistor Q4, and the second output terminal of the half-bridge driver U5 is connected to the G pole of Q12; the first output terminal of the half-bridge driver U6 is connected to the G pole of the MOS transistor Q5, and the second output terminal of the half-bridge driver U6 is connected to the G pole of Q13; the first output terminal of the half-bridge driver U7 is connected to the G pole of the MOS transistor Q6, and the second output terminal of the half-bridge driver U7 is connected to the G pole of Q14;

[0027] The first branch of the D pole of the MOS transistor Q3 is connected to the D pole of the MOS transistor Q2, and the second branch of the D pole of the MOS transistor Q3 is connected to the D pole of the MOS transistor Q4; the first branch of the S pole of the MOS transistor Q3 is connected to the D pole of the MOS transistor Q11; the first branch of the S pole of the MOS transistor 11 is connected to the second branch of the MOS transistor Q10 through the resistor R6; the second branch of the S pole of the MOS transistor 11 is connected to the S pole of the MOS transistor Q12 and then grounded; the first branch of the D pole of the MOS transistor Q12 is connected to the S pole of the MOS transistor Q4, and the second branch of the D pole of the MOS transistor Q12 is connected to one end of the low-voltage side of the transformer T1, and the other end of the low-voltage side of the transformer T1 is connected to the second branch of the S pole of the MOS transistor Q3 to ground;

[0028] One end of the high-voltage side of the transformer T1 is connected to the first branch of the S pole of the MOS transistor Q5 through the series-connected capacitor C1 and inductor L1; the second branch of the S pole of the MOS transistor Q5 is connected to the D pole of the MOS transistor Q13, and the first branch of the S pole of the MOS transistor Q13 is connected to the S pole of the MOS transistor Q14; the first branch of the D pole of the MOS transistor Q14 is connected to the other end of the high-voltage side of the transformer T1, and the second branch of the D pole of the MOS transistor Q14 is connected to the S pole of the MOS transistor Q6; the first branch of the D pole of the MOS transistor Q6 is connected to the D pole of the MOS transistor Q5, and the second branch of the D pole of the MOS transistor Q6 is used to connect to the bidirectional inverter module, and a non-polar capacitor C4 and a polarized capacitor C2 are also connected in parallel between the second branch of the D pole of the MOS transistor Q6 and the second branch of the S pole of the MOS transistor Q14, and the positive pole of the polarized capacitor C2 is connected to the second branch of the D pole of the MOS transistor Q6;

[0029] The acquisition unit further includes an acquisition sub-unit U13, an acquisition sub-unit U16 and an acquisition sub-unit U20; the acquisition sub-unit U13 is used to acquire the voltage across the resistor R6; the acquisition sub-unit U16 is used to acquire the voltage across the capacitor C4, and the acquisition sub-unit U20 is used to acquire the current on the high-voltage side of the transformer T1.

[0030] The positive and negative poles of the output terminal of the auxiliary power supply U19 are respectively connected to the D pole of the MOS transistor Q6 and the S pole of the MOS transistor Q14.

[0031] Preferably, the bidirectional inverter module includes a half-bridge driver U8 and a half-bridge driver U9; the power input terminals of the half-bridge driver U8 and the half-bridge driver U9 are connected to the fourth output terminal of the first auxiliary power supply U1; the signal input terminals of the half-bridge driver U8 and the half-bridge driver U9 are connected to the driving unit, the first output terminal of the half-bridge driver U8 is connected to the G pole of the MOS transistor Q7, and the second output terminal of the half-bridge driver U8 is connected to the G pole of the MOS transistor Q15; the first output terminal of the half-bridge driver U9 is connected to the G pole of the MOS transistor Q8, and the first output terminal of the half-bridge driver U9 is connected to the G pole of the MOS transistor Q16;

[0032] The first branch of the D pole of the MOS transistor Q7 is connected to the second branch of the D pole of the MOS transistor Q6, the second branch of the D pole of the MOS transistor Q7 is connected to the D pole of the MOS transistor Q8, the first branch of the S pole of the MOS transistor Q8 is connected to the D pole of the MOS transistor Q16, the first branch of the S pole of the MOS transistor Q16 is connected to the S pole of Q15, and the second branch of the S pole of the MOS transistor Q16 is connected to the second branch of the S pole of the MOS transistor Q14; the first branch of the D pole of the MOS transistor Q15 is connected to the S pole of the MOS transistor Q7;

[0033] The second branch of the D pole of the MOS transistor Q15 is connected to one end of the first winding of the common-mode inductor T2. A resistor R2 and a resistor R3 are connected in series at the other end of the first winding, and then connected to one end of the first winding of the common-mode inductor T3; one end of the second winding of the common-mode inductor T3 is connected to one end of the second winding of the common-mode inductor T2, and the other end of the second winding of the common-mode inductor T2 is connected to the second branch of the S pole of the MOS transistor Q8; A capacitor C5 is connected across between the resistors R2 and R3 and between the second winding of the common-mode inductor T2 and the second winding of the common-mode inductor T3; the other end of the first winding of the common-mode inductor T3 is connected to the first terminal J2 of the second power supply, and the other end of the second winding of the common-mode inductor T3 is connected to the second terminal J3 of the second power supply; A capacitor C3 is connected across between the first terminal J2 and the second terminal J3;

[0034] The acquisition unit further includes an acquisition sub-unit U14, an acquisition sub-unit U17, an acquisition sub-unit U18, and an acquisition sub-unit U23. The acquisition sub-unit U14 is used to acquire the voltage input or output by the common-mode inductor T3; the acquisition sub-unit U17 is used to acquire the voltage across the resistor R2; the acquisition sub-unit U18 is used to acquire the voltage across the resistor R3.

[0035] The beneficial effect of this solution is:

[0036] 1. This solution is configured with a DC terminal, a bidirectional voltage stabilization module, a resonant conversion module, a bidirectional inverter module, and an AC terminal, as well as an auxiliary power supply and a control module. It can achieve step-up and step-down bidirectional inversion of DC to AC and AC to DC. The control module drives them based on the voltage values of the bidirectional voltage stabilization module, the resonant conversion module, and the bidirectional inverter module, and can achieve bidirectional maximum power input during inversion. Through the setting of the reverse connection prevention module, it can effectively avoid circuit damage caused by reverse connection at the DC terminal.

[0037] 2. In this solution, for the bidirectional voltage stabilization module, a parallel group of polarized capacitors and non-polarized capacitors is set at both the first end and the second end of the bidirectional voltage stabilization module. Through this setting, the reactive power loss input to the bidirectional voltage stabilization module is reduced, the voltage fluctuation between them can also be reduced, and the stability is improved.

[0038] In the bidirectional voltage stabilization module, MOS transistor Q1 and MOS transistor Q9 form an independent complementary PWM-driven left bridge arm, and MOS transistor Q2 and MOS transistor Q10 form a complementary PWM-driven right bridge arm. The switching frequencies of the left and right bridge arms are the same, the phases are the same, and the duty cycles are different. The control module judges by comparing the input voltage with the set voltage. According to the different comparison values, it controls the bidirectional voltage stabilization module to output PWM to drive the left and right bridge arms for input step-up or input step-down, and can better control the maximum input power.

[0039] 3. In the resonant conversion module, through the connection and combination of components such as capacitors and inductors, the DC input can be DC-resonated, that is, the voltage and current of the DC input are periodically changed. Then, the DC input is directly stepped up through transformer T1, and at the same time, it can be adjusted in real time according to the parameters of the DC input, making the DC input and DC output inside more stable. Description of the Drawings

[0040] Figure 1 It is a schematic connection structure diagram of the step-up and step-down bidirectional inverter circuit of the present invention.

[0041] Figure 2 It is a circuit diagram of the step-up and step-down bidirectional inverter circuit of the present invention. Detailed Embodiment

[0042] The following elaborates on the preferred embodiments of the present invention in detail with reference to the drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making the protection scope of the present invention more clearly defined. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0043] Embodiment:

[0044] As Figure 1 shown:

[0045] A step-up and step-down bidirectional inverter circuit includes a first power supply, a bidirectional voltage stabilizing module, a resonant conversion module, a bidirectional inverter module, and a second power supply; the first power supply is connected to the first end of the bidirectional voltage stabilizing module, the second end of the bidirectional voltage stabilizing module is connected to the first end of the resonant conversion module, the second end of the resonant conversion module is connected to the first end of the bidirectional inverter module, and the second end of the bidirectional inverter module is connected to the second power supply;

[0046] Wherein the bidirectional voltage stabilizing module is used to receive the DC input from the first power supply or the first end of the resonant conversion module and output a DC output with a set value; the resonant conversion module is used to receive the DC input from the second end of the bidirectional voltage stabilizing module or the first end of the bidirectional inverter module and step up or step down the DC input; the bidirectional inverter module is used to receive the DC input from the second end of the resonant conversion module or the AC input of the second power supply and convert the DC input into an AC output or convert the AC input into a DC output;

[0047] It further includes a control module and an auxiliary power supply module. The control module includes an acquisition unit and a driving unit. The acquisition unit is used to acquire the voltage or current signals of the bidirectional voltage stabilizing module, the resonant conversion module, and the bidirectional inverter module. The driving unit is used to provide control signals for the voltage stabilizing module, the resonant conversion module, and the bidirectional inverter module according to the acquired voltage and current signals to achieve dynamic regulation; the auxiliary power supply module is used to provide driving energy for driving the bidirectional voltage stabilizing module, the resonant conversion module, and the bidirectional inverter module.

[0048] The working mode of the inverter circuit according to this solution:

[0049] When the inverter circuit is in the inverter mode: the first power supply is used to output low-voltage DC; the low-voltage DC is input to the first end of the bidirectional voltage stabilizing module and then output from the second end of the bidirectional voltage stabilizing module. The bidirectional voltage stabilizing module converts the low-voltage DC input into a stable voltage and outputs it to the second end according to the set value;

[0050] During the voltage stabilization process, the acquisition unit will collect the input voltage of the first power supply in real time, and the driving unit will drive the bidirectional voltage stabilizing module according to the real-time acquired input voltage, so that the bidirectional voltage stabilizing module dynamically adjusts the DC input, that is, raises or lowers the DC input to the set voltage and outputs it.

[0051] The DC input after voltage stabilization enters the resonant conversion module from the first end of the resonant conversion module. The resonant conversion module converts the input low-voltage DC into high-voltage DC and outputs the high-voltage DC from the second end of the resonant conversion module;

[0052] When the voltage is increased, the acquisition unit collects the DC input of the resonant conversion module in real time. The driving unit adjusts and drives the resonant conversion module in real time according to the input voltage value collected in real time, performs resonant conversion on the DC input, so that the voltage and current of the DC input are periodically changed to facilitate voltage increase. Finally, the input voltage is processed to a set value to obtain a stable high-voltage DC;

[0053] The high-voltage DC is input from the first end of the bidirectional inverter module. The bidirectional inverter module converts the high-voltage DC into high-voltage AC, and the high-voltage AC is output from the second end of the bidirectional inverter module to the second power supply end to complete the inversion from DC to AC;

[0054] When performing inversion, in order to ensure the stability of the output voltage of the bidirectional inverter module, the acquisition unit will collect the input voltage at the first end of the bidirectional inverter module at any time, and the driving unit will control and adjust the bidirectional inverter module according to the input voltage to make the output high-voltage AC stable.

[0055] When the inverter circuit is in the rectification mode:

[0056] The second power supply is used for high-voltage AC input, where the high-voltage AC is input from the second end of the bidirectional inverter module; the bidirectional inverter module converts the input high-voltage AC into high-voltage DC and outputs it from the first end of the bidirectional inverter module to the second end of the resonant conversion module. The resonant conversion module converts the input high-voltage DC into low-voltage DC and converts the low-voltage DC to the second end of the bidirectional voltage regulator module. The bidirectional voltage regulator module converts the input low-voltage DC into stable low-voltage DC and outputs it from the first end of the bidirectional voltage regulator module to the DC end to achieve rectification;

[0057] In this mode, the acquisition unit still collects the voltage of the above modules in real time, and the driving unit adjusts the operation of the above modules in real time according to the collected voltage value, and the output low-voltage DC is stable and all maintain the maximum power input.

[0058] Such as Figure 2 , specifically, in order to prevent the first power supply from being damaged by reverse current, an anti-reverse connection module is provided at its connection with the bidirectional voltage regulator module. The connection relationship of each component of the anti-reverse connection module is as follows: including a resistor R1. One first branch of one end of the resistor R1 is connected to the positive electrode J1 of the first power supply, and the second branch is connected to the bidirectional voltage regulator module; one first branch of the other end of the resistor R1 is connected to the G pole of the MOS transistor Q17, and the second branch is connected to the negative electrode of the zener diode D1; the D pole of the MOS transistor Q17 is connected to the negative electrode J4 of the first power supply, and one first branch of the S pole of the MOS transistor Q17 is connected to the positive electrode of the zener diode D1; the negative electrode of the zener diode is grounded through a resistor R4 with the G pole of the MOS transistor Q17 (it should be noted that in this solution, the MOS transistor is an NMOS transistor, the G pole is the gate, the S pole is the source, and the D pole is the drain);

[0059] In this anti-reverse connection module, an MOS transistor is selected as the core component for anti-reverse connection. When the input power supply is reversely connected, the MOS transistor Q17 is not conducting, there is no current loop, and it will not burn out. At the same time, the resistance of the MOS transistor is very small and the power consumption is low, thus reducing the heat generation.

[0060] In this solution, the auxiliary power supply module includes auxiliary power supply U1 and auxiliary power supply U19. Both the auxiliary power supply U1 and auxiliary power supply U19 in this solution are multi-channel flyback auxiliary power supplies. Both U1 and the auxiliary power supply U19 have a UCC3843 chip. Such power supplies have few external components, low cost, can achieve high-efficiency PWM control, and have good stability.

[0061] Among them, the auxiliary power supply U1 has at least one input terminal and five output terminals. All five output terminals are used to supply power to the bidirectional voltage stabilization module, the resonance conversion module, and the bidirectional inverter module. During implementation, the negative electrodes of the auxiliary power supplies U1 and U19 are directly connected to the negative electrode J4 of the first power supply, and their positive electrode J1 is connected to the negative electrode of the diode D2. The positive electrode of the diode D2 is connected to the positive electrode J1 of the first power supply. In this way, the first power supply J4 can replenish electrical energy to the auxiliary power supplies U1 and U19, and the setting of the diode D2 can prevent reverse flow from damaging the first power supply.

[0062] During implementation, the bidirectional voltage stabilization module includes a polarized capacitor C6 and a non-polarized capacitor C9. The polarized capacitor C6 and the non-polarized capacitor C9 are connected across the positive and negative electrodes of the first power supply. The positive electrode of the polarized capacitor C6 is connected to the positive electrode J1 of the first power supply.

[0063] The bidirectional voltage stabilization module also includes a half-bridge driver U2 and a half-bridge driver U3. The power input terminals of the half-bridge drivers U2 and U3 are connected in parallel and then connected to the first output terminal of the auxiliary power supply. The signal input terminals of the half-bridge drivers U2 and U3 are respectively connected to the driving unit. The first output terminal of the half-bridge driver U2 is connected to the G pole of the MOS transistor Q1, and the second output terminal of the half-bridge driver U2 is connected to the G pole of Q9. The first output terminal of the half-bridge driver U3 is connected to the G pole of the MOS transistor Q2, and the second output terminal of the half-bridge driver is connected to the G pole of the MOS transistor Q10.

[0064] The D pole of the MOS transistor Q1 is connected to the second branch on the first power supply side through the resistor R1. The first branch of the S pole of the MOS transistor Q1 is connected to the D pole of the MOS transistor Q9. The first branch of the S pole of the MOS transistor Q9 is connected to the second branch of the S pole of the MOS transistor Q17 through the resistor R5. The second branch of the S pole of the MOS transistor Q9 is connected to the first branch of the S pole of the MOS transistor Q10. The first branch of the D pole of the MOS transistor Q10 is connected to the S pole of the MOS transistor Q2. The second branch of the D pole of the MOS transistor Q10 is connected to the second branch of the S pole of the MOS transistor Q1 through the inductor L2.

[0065] The two-way voltage stabilizing module further includes a polarized capacitor C7 and a non-polarized capacitor C8, and the polarized capacitor C7 and the non-polarized capacitor C8 are connected in a cross manner between the D pole of the MOS transistor Q2 and the second branch of the S pole of the MOS transistor Q10; the D pole of the MOS transistor Q2 and the second branch of the S pole of the MOS transistor Q10 are also used for connecting to the first end of the resonant conversion module;

[0066] The acquisition unit includes an acquisition subunit U11, an acquisition subunit U12, and an acquisition subunit U15. The acquisition subunit U11 is used for acquiring the voltage across the capacitor C9, the acquisition subunit U12 is used for acquiring the voltage across the capacitor C8, and the acquisition subunit U15 is used for acquiring the voltage across the resistor R5.

[0067] The resonant conversion module includes a half-bridge driver U4, a half-bridge driver U5, a half-bridge driver U6, and a half-bridge driver U7 whose signal input ends are connected to the drive unit; among them, the power input ends of the half-bridge driver U4 and the half-bridge driver U5 are connected to the second output end of the auxiliary power supply U1; the power input ends of the half-bridge driver U6 and the half-bridge driver U7 are connected to the third output end of the auxiliary power supply U1;

[0068] The first output end of the half-bridge driver U4 is connected to the G pole of the MOS transistor Q3, and the second output end of the half-bridge driver U4 is connected to the G pole of Q11; the first output end of the half-bridge driver U5 is connected to the G pole of the MOS transistor Q4, and the second output end of the half-bridge driver U5 is connected to the G pole of Q12; the first output end of the half-bridge driver U6 is connected to the G pole of the MOS transistor Q5, and the second output end of the half-bridge driver U6 is connected to the G pole of Q13; the first output end of the half-bridge driver U7 is connected to the G pole of the MOS transistor Q6, and the second output end of the half-bridge driver U7 is connected to the G pole of Q14;

[0069] The first branch of the D pole of the MOS transistor Q3 is connected to the D pole of the MOS transistor Q2, and the second branch of the D pole of the MOS transistor Q3 is connected to the D pole of the MOS transistor Q4; the first branch of the S pole of the MOS transistor Q3 is connected to the D pole of the MOS transistor Q11; the first branch of the S pole of the MOS transistor 11 is connected to the second branch of the MOS transistor Q10 through the resistor R6; the second branch of the S pole of the MOS transistor 11 is connected to the G pole of the MOS transistor Q12 and then grounded; the first branch of the D pole of the MOS transistor Q12 is connected to the S pole of the MOS transistor Q4, the second branch of the D pole of the MOS transistor Q12 is connected to one end of the low-voltage side of the transformer T1, and the other end of the low-voltage side of the transformer T1 is connected to the second branch of the S pole of the MOS transistor Q3 to ground;

[0070] One end of the high-voltage side of transformer T1 is connected to the first branch of the S pole of MOS transistor Q5 through a series-connected capacitor C1 and inductor L1; the second branch of the S pole of MOS transistor Q5 is connected to the D pole of MOS transistor Q13, and the first branch of the S pole of MOS transistor Q13 is connected to the S pole of MOS transistor Q14; the first branch of the D pole of MOS transistor Q14 is connected to the other end of the high-voltage side of transformer T1, and the second branch of the D pole of MOS transistor Q14 is connected to the S pole of MOS transistor Q6; the first branch of the D pole of MOS transistor Q6 is connected to the D pole of MOS transistor Q5, and the second branch of the D pole of MOS transistor Q6 and the second branch of the S pole of MOS transistor Q14 are used to connect to the bidirectional inverter module. An electrolytic capacitor C2 and a non-polar capacitor C4 are also connected in parallel between the second branch of the D pole of MOS transistor Q6 and the second branch of the S pole of MOS transistor Q14, and the positive pole of electrolytic capacitor C2 is connected to the second branch of the D pole of MOS transistor Q6;

[0071] The acquisition unit further includes an acquisition sub-unit U13, an acquisition sub-unit U16, and an acquisition sub-unit U20; the acquisition sub-unit U13 is used to acquire the voltage across resistor R6; the acquisition sub-unit U16 is used to acquire the voltage across capacitor C4, and the acquisition sub-unit U20 is used to acquire the current on the high-voltage side of transformer T1.

[0072] The positive and negative poles of the output terminal of auxiliary power supply U19 are respectively connected to the D pole of MOS transistor Q6 and the S pole of MOS transistor Q14.

[0073] The bidirectional inverter module includes a half-bridge driver U8 and a half-bridge driver U9; the power input terminals of the half-bridge driver U8 and the half-bridge driver U9 are connected to the fourth output terminal of the first auxiliary power supply U1; the signal input terminals of the half-bridge driver U8 and the half-bridge driver U9 are connected to the drive unit. The first output terminal of the half-bridge driver U8 is connected to the G pole of MOS transistor Q7, and the second output terminal of the half-bridge driver U8 is connected to the G pole of MOS transistor Q15; the first output terminal of the half-bridge driver U9 is connected to the G pole of MOS transistor Q8, and the first output terminal of the half-bridge driver U9 is connected to the G pole of MOS transistor Q16;

[0074] The first branch of the D pole of MOS transistor Q7 is connected to the second branch of the D pole of MOS transistor Q6, the second branch of the D pole of MOS transistor Q7 is connected to the D pole of MOS transistor Q8, the first branch of the S pole of MOS transistor Q8 is connected to the D pole of MOS transistor Q16, the first branch of the S pole of MOS transistor Q16 is connected to the S pole of Q15, and the second branch of the S pole of MOS transistor Q16 is connected to the second branch of the S pole of MOS transistor Q14; the first branch of the D pole of MOS transistor Q15 is connected to the S pole of MOS transistor Q7;

[0075] The second branch of the D pole of MOS transistor Q15 is connected to one end of the first winding of common-mode inductor T2. The other end of the first winding is connected in series with resistor R2 and resistor R3, and then connected to one end of the first winding of common-mode inductor T3. One end of the second winding of common-mode inductor T3 is connected to one end of the second winding of common-mode inductor T2. The other end of the second winding of common-mode inductor T2 is connected to the second branch of the S pole of MOS transistor Q8. A capacitor C5 is connected across between resistor R2 and R3 and between the second winding of common-mode inductor T2 and the second winding of common-mode inductor T3. The other end of the first winding of common-mode inductor T3 is connected to the first terminal J2 of the second power supply. The other end of the second winding of common-mode inductor T3 is connected to the second terminal J3 of the second power supply. A capacitor C3 is connected across between the first terminal J2 and the second terminal J3.

[0076] The acquisition unit further includes acquisition sub-unit U14, acquisition sub-unit U17, acquisition sub-unit U18 and acquisition sub-unit U23. Acquisition sub-unit U14 is used to acquire the voltage input or output by common-mode inductor T3. Acquisition sub-unit U17 is used to acquire the voltage across resistor R2. Acquisition sub-unit U18 is used to acquire the voltage across resistor R3.

[0077] The implementation principle of this embodiment is:

[0078] Inverter mode:

[0079] Implementation principle of inverter mode: The power supply is input from the first power supply, and the voltage is stabilized at a fixed DC voltage value through the bidirectional voltage stabilizing module. Then, the voltage is boosted to a high-voltage DC voltage through the resonant conversion module. Finally, it is inverted into the output industrial-frequency alternating current through the bidirectional inverter module.

[0080] Rectification mode:

[0081] The industrial-frequency alternating current is input from the second power supply terminal, rectified by the bidirectional inverter module and the PFC value is adjusted to output a high-voltage DC voltage. Then, the voltage is stepped down through the resonant conversion module, and then a low-voltage DC is output through the bidirectional voltage stabilizing module.

[0082] Specifically in the inverter mode: First, U1 converts the input DC into multiple isolated DC voltages to supply power to each half-bridge driver U2~U9 respectively. One of the power transmissions through U2~U9 steps down the voltage to supply power to the acquisition units U10~U18.

[0083] The low-voltage DC passes through the filtering of polar capacitor C6 and non-polar capacitor C9. The input voltage forms a stable turn-on voltage between pins 1 and 3 of Q17 through R1, D1, and R4, turning on MOS transistor Q17. MOS transistor Q17 can prevent the circuit from being burned out due to the reverse connection of the positive and negative poles at the DC end.

[0084] In the bidirectional voltage stabilizing module, MOS transistor Q1 and MOS transistor Q9 form an independent complementary PWM-driven left bridge arm, and MOS transistor Q2 and MOS transistor Q10 form a complementary PWM-driven right bridge arm. The left and right bridge arms have the same switching frequency, the same phase, and different duty cycles.

[0085] When the bidirectional voltage stabilizing module is operating, a voltage range is set according to requirements. When the input voltage is less than the set range, boost processing is performed. When it is greater than the set voltage range, buck processing is performed, so that the input voltage is converted into a voltage within the set range and stably output.

[0086] When performing input boost, the duty cycle of MOS transistor Q1 is 100%, and the duty cycle of MOS transistor Q9 is 0%. The driving unit outputs PWM to drive U2.

[0087] The right bridge arm and inductor L2 form a BOOST circuit. The driving unit collects the input voltage through acquisition units U11 and U12, and the built-in algorithm of the driving unit calculates the PWM duty cycle required for stable voltage output, and then outputs PWM to U3 to control the on and off of MOS transistor Q2 and MOS transistor Q10 to make L2 boost and output. Due to the existence of C7 and C8, the boost voltage is clamped to achieve stability.

[0088] By acquiring the magnitude and direction of the current flowing through R5 in real time through acquisition unit U15, and combining with the input voltage value, the maximum input power of the first power supply terminal can be controlled through the internal MPPT algorithm. The input buck and direct connection of the bidirectional voltage stabilizing module are similar to the above boost, and will not be described in detail here.

[0089] For the resonant conversion module, MOS transistor Q3 and MOS transistor Q11 form the left bridge arm of the low-voltage side in the inverter mode.

[0090] MOS transistor Q4 and MOS transistor Q12 form the right bridge arm of the low-voltage side in the inverter mode. The switching frequency and duty cycle of the two bridge arms are the same as those of the left bridge arm, and the phase difference is 180°. The fixed turns ratio transformer T1, resonant capacitor C1 and L1 resonant inductor form a resonant cavity.

[0091] MOS transistor Q5 and MOS transistor Q13 form the left bridge arm of the boost side in the inverter mode, and the driving waveform is the same as that of the right bridge arm of the LLC low-voltage side; MOS transistor Q6 and MOS transistor Q14 form the right bridge arm of the high-voltage side in the inverter mode, and the driving waveform is the same as that of the left bridge arm of the low-voltage side; The auxiliary power supply U19 outputs a signal to the driving unit as a current sampling circuit.

[0092] The acquisition unit collects the input voltage, output voltage and internal voltage of the resonant conversion module through U12, U13, and U16 respectively. The internal algorithm of the drive unit calculates the frequency required for boosting, adjusts the PWM, and then outputs the PWM to the half-bridge drivers U4 and U5 respectively to drive the left and right bridge arms on the low-voltage side to establish a magnetic field on the transformer T1 to transfer energy to the high-voltage side. At the same time, the drive unit outputs PWM to the half-bridge drivers U6 and U7 to drive the left and right bridge arms on the high-voltage side to synchronize the drive waveforms on the low-voltage side to complete the rectification of the high-voltage side power signal. The rectified waveform enters C4 and C2 for filtering to reduce the ripple, completing the conversion from low-voltage DC to high-voltage DC.

[0093] For the bidirectional inverter module, MOS transistor Q7 and MOS transistor Q15 form the left bridge arm of the inverter module; MOS transistor Q8 and MOS transistor Q16 form the right bridge arm of the full-bridge inverter module; the current transformer T2 and the capacitor C5 form a low-pass filter; the resistors R2 and R3 are respectively used as the sampling resistors for the induced current and the output current; the current transformer T3 and the capacitor C3 are used as the secondary low-pass filter.

[0094] The internal algorithm of the drive unit outputs PWM to the half-bridge drivers U8 and U9 respectively to drive the left and right bridge arms of the MOS transistors to generate a high-frequency carrier containing sinusoidal modulation on both sides of the LCL filter composed of T2 and C5. After the waveform is filtered by the LCL filter of T2 and C5, a power-frequency sinusoidal voltage is generated. The acquisition unit U14, U17, and U18 respectively collect the output voltage, output current, and inductor current to perform feedback control on the output power, and then limit the output current. Then, the power-frequency alternating current passes through the filter composed of the current transformer T2 and the capacitor C3 to output a sinusoidal wave with low harmonics, outputting high-voltage alternating current.

[0095] The rectification mode is specifically as follows:

[0096] The power-frequency alternating current passes through the capacitor C3 and the common-mode inductor T3 for filtering and then enters through the resistor R3, and then a low-harmonic power-frequency sinusoidal wave is generated at both ends of the capacitor C5. Among them, MOS transistor Q7, MOS transistor Q8, MOS transistor Q15, MOS transistor Q16, common-mode inductor T2, capacitor C4, and capacitor C2 form a bridge-less CCM totem-pole PFC (power factor correction) circuit.

[0097] When the alternating current is in the positive half-cycle, the drive unit locks the phase of the input alternating voltage through the detection subunit U14, detects that J2 is positive and J3 is negative. In the positive half-cycle state, the drive unit outputs a set of power-frequency PWM complementary waveforms with the same phase and frequency as the input alternating current through the half-bridge driver U8 to make the duty cycle of MOS transistor Q15 100% and the duty cycle of MOS transistor Q7 0%. The drive unit outputs a set of high-frequency PWM complementary waveforms to the half-bridge driver U9 to drive MOS transistor Q8 and MOS transistor Q16.

[0098] When it is within the effective level time, MOS transistor Q16 is turned on, MOS transistor Q8 is turned off, and MOS transistors Q16, capacitor C5, and MOS transistor Q15 complete the energy storage of T2; during the idle level time within the high-frequency switching cycle, Q16 is turned off, Q8 is turned on, C5, Q15, and T2 release energy to form a BOOST circuit to charge C2, and the current waveform flowing through the inductor is collected by the acquisition subunit U17, and the PWM duty cycle is adjusted through the internal algorithm of the drive unit to complete the PFC adjustment of the inductor current during the positive half cycle.

[0099] When the alternating current is in the negative half cycle, the drive unit collects the phase of the input alternating voltage through the acquisition subunit U14, detects that the second terminal J3 of the second power supply is positive and the first terminal J2 of the second power supply is negative. In the negative half cycle state, the drive unit outputs a set of industrial frequency PWM complementary waveforms with the same phase and frequency as the input alternating current; through the half-bridge drive U8, the duty cycle of MOS transistor Q7 is 100%, and the duty cycle of MOS transistor Q15 is 0%. The drive unit outputs a set of high-frequency PWM complementary waveforms to the half-bridge drive U9 to drive MOS transistors Q8 and Q16.

[0100] When it is within the effective level time, MOS transistor Q8 is turned on, MOS transistor Q16 is turned off, and MOS transistors Q8, capacitor C5, and MOS transistor Q7 complete the energy storage of the common-mode inductor T2; when it is within the idle level time, MOS transistor Q8 is turned off, MOS transistor Q16 is turned on, capacitor C5, MOS transistor Q7, and common-mode inductor T2 release energy to charge capacitor C2, and the inductor current waveform is collected by the acquisition subunit U17, and the PWM duty cycle is adjusted through the internal algorithm of the drive unit to complete the PFC adjustment of the inductor current during the positive half cycle.

[0101] Specifically, MOS transistors Q3 and Q11 form the left bridge arm of the low-voltage side synchronous rectifier bridge of the full-bridge LLC buck circuit in the rectification mode.

[0102] MOS transistors Q4 and Q12 form the right bridge arm of the low-voltage side synchronous rectifier bridge of the full-bridge LLC buck circuit in the rectification mode. Its switching frequency and duty cycle are the same as those of the left bridge arm, and the phase differs from the left bridge arm by 180°.

[0103] T1 is a fixed turns ratio transformer, and the C1 resonant capacitor and the L1 resonant inductor form an LLC resonant cavity.

[0104] MOS transistors Q5 and Q13 form the left bridge arm of the high-voltage side of the full-bridge LLC buck circuit in the rectification mode, and the drive waveform is the same as that of the right bridge arm of the low-voltage side of the LLC buck circuit.

[0105] MOS transistors Q6 and Q14 form the right bridge arm of the high-voltage side of the full-bridge LLC buck circuit in the rectification mode, and the drive waveform is the same as that of the left bridge arm of the low-voltage side of the LLC buck circuit.

[0106] The auxiliary power supply U19 provides a signal output to the drive unit as an LLC circuit.

[0107] The acquisition sub-units U12, U13, and U16 respectively acquire corresponding signals. The drive unit calculates the required frequency for LLC step-down through its internal algorithm, adjusts the PWM, and then outputs the PWM to the half-bridge drive U6 respectively. The half-bridge U6 drives the left and right bridge arms on the high voltage side to establish a magnetic field on the transformer T1 to transfer energy to the low voltage side. At the same time, the drive unit outputs PWM to the half-bridge drives U4 and U5 to drive the left and right bridge arms on the low voltage side to synchronize the drive waveforms on the high voltage side to complete the rectification of the power signal on the low voltage side. The rectified waveform enters the capacitors C7 and C8 for filtering to reduce the ripple and stabilize the voltage.

[0108] The MOS transistors Q1, Q2, Q9, Q10, the inductor L2, and the resistor R5 form a bidirectional voltage stabilization module. The MOS transistors Q1 and Q9 form an independent complementary PWM-driven left bridge arm, and the MOS transistors Q2 and Q10 form a complementary PWM-driven right bridge arm. The switching frequencies of the left and right bridge arms are the same, the phases are the same, and the duty cycles are different.

[0109] A fixed voltage value and a maximum current value are set according to requirements. When the voltage value output by the resonant conversion module is greater than the set voltage value, the bidirectional voltage stabilization module operates in the boost mode; otherwise, it is in the buck mode. When the voltage difference is within a small range (for example, ±0.5V), the bidirectional voltage stabilization module operates in the through mode. By collecting the current of R5 to limit the output current, the maximum output power can be controlled.

[0110] This embodiment also provides another different implementation manner. In this implementation manner, there is also a third power supply and a power factor correction module. The third power supply is connected to the input end of the power factor correction module, and the output end of the power factor correction module is connected to the first end of the bidirectional inverter module. Specifically, the power factor correction module includes the half-bridge drive U22, the full-bridge rectification unit D4, the inductor L3, the MOS transistor Q18, the capacitors C10, C11, the diode D3, the current transformer T4, and the capacitor C12.

[0111] The first auxiliary power supply further includes a fifth output terminal. The fifth output terminal of the first auxiliary power supply is connected to U22. The output terminal of U22 is connected to the G pole of MOS transistor Q18. The D pole of MOS transistor Q18 is respectively connected to the positive pole of diode D3 and one end of inductor L3. The negative pole of diode D3 is connected to the D pole of MOS transistor Q7. The S pole of MOS transistor Q18 is connected to the S pole of MOS transistor Q15. One set of relative connection points of the full-bridge rectification unit D4 is respectively connected to the other end of inductor L3 and the S pole of MOS transistor Q18. The other set of relative pins of the full-bridge rectification unit D4 is connected to one end of transformer T4. The other end of transformer T4 is connected to the first input terminal J5 and the second input terminal J6 of the third power supply. Capacitors C11 and C12 are respectively arranged at both ends of transformer T4. Both ends of capacitor C10 are respectively connected to the S pole of MOS transistor Q18 and the connection point of inductor L3 and the full-bridge rectification sub-unit D4. The acquisition unit further includes acquisition sub-units U21 and U23. The acquisition sub-unit U21 is arranged between diode D3 and inductor L3 for current acquisition. The acquisition sub-unit U23 is arranged between the first input terminal and the second input terminal of the third power supply for voltage acquisition.

[0112] In this embodiment, the second output terminal inputs industrial frequency alternating current with a frequency of 50HZ or 60HZ and an alternating voltage range of 85V to 280V. After passing through the filter composed of capacitor C12, transformer T4, and capacitor C11, it enters the PFC circuit. The PFC circuit is composed of MOS transistors Q7, Q8, Q15, Q16, transformer T2, capacitor C, and capacitor C2. D4 converts the input industrial frequency alternating current into half-wave direct current. Then, based on the sampling signal of the sampling unit U23, the driving unit outputs a PWM waveform to U22 to drive MOS transistor Q18. MOS transistor Q18, diode D3, and inductor L3 boost and stabilize the input half-wave direct current, and then through the bidirectional inverter module, the required industrial frequency alternating current is inverted and output to complete frequency conversion and improve power quality.

[0113] Frequency modulation mode: The third power supply inputs the voltage to be frequency modulated. After passing through the power factor correction module, the voltage is stabilized at the bidirectional inverter module, and finally, through the bidirectional inverter module, industrial frequency alternating current is output to the second power supply terminal to complete frequency modulation.

[0114] It should be noted that in this solution, the driving unit of the control module is the TMS320 series. The half-bridge drivers U2 - U9 and the half-bridge driver U22 all adopt the NSI6602 series. The acquisition sub-units U11 - U18 adopt a conventional differential operational amplifier circuit + isolation transmission. Specifically, the differential operational amplifier circuit adopts LM358 or MCP6002, and the isolation transmission is the NSI1311 series. The acquisition sub-units U20 and U21 are of the CA-IS23050W series.

[0115] Although the embodiments of the present utility model have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present utility model. The scope of the present utility model is defined by the appended claims.

Claims

1. A boost - buck bidirectional inverter circuit, characterized in that: It includes a first power supply, a bidirectional voltage - stabilizing module, a resonant conversion module, a bidirectional inverter module and a second power supply; the first power supply is connected to the first end of the bidirectional voltage - stabilizing module, the second end of the bidirectional voltage - stabilizing module is connected to the first end of the resonant conversion module, the second end of the resonant conversion module is connected to the first end of the bidirectional inverter module, and the second end of the bidirectional inverter module is connected to the second power supply; The bidirectional voltage - stabilizing module is used to receive the DC input from the first power supply or the first end of the resonant conversion module and output a set DC output; the resonant conversion module is used to receive the DC input from the second end of the bidirectional voltage - stabilizing module or the first end of the bidirectional inverter module and step up or step down the DC input; the bidirectional inverter module is used to receive the DC input from the second end of the resonant conversion module or the AC input from the second power supply and convert the DC input into an AC output or convert the AC input into a DC output; It also includes a control module and an auxiliary power supply module. The control module includes an acquisition unit and a driving unit which are electrically connected. The acquisition unit and the driving unit are respectively connected to the bidirectional voltage - stabilizing module, the resonant conversion module and the bidirectional inverter module through wires. The driving unit is used to control the voltage - stabilizing module, the resonant conversion module and the bidirectional inverter module according to the electrical signals provided by the acquisition unit; the output end of the auxiliary power supply module is respectively connected to the bidirectional voltage - stabilizing module, the resonant conversion module and the bidirectional inverter module through wires; An anti - reverse connection module is also arranged between the first power supply and the bidirectional voltage - stabilizing module. The anti - reverse connection module includes a resistor R1. One end of the resistor R1 has a first branch connected to the positive pole J1 of the first power supply, and a second branch connected to the bidirectional voltage - stabilizing module; the other end of the resistor R1 has a first branch connected to the G - pole of the MOS transistor Q17, and a second branch connected to the negative pole of the zener diode D1; the D - pole of the MOS transistor Q17 is connected to the negative pole J4 of the first power supply, and the first branch of the S - pole of the MOS transistor Q17 is connected to the positive pole of the zener diode D1; the negative pole of the zener diode is grounded through a resistor R4 connected to the G - pole of the MOS transistor Q17.

2. The buck-boost bidirectional inverter circuit according to claim 1, wherein: The auxiliary power supply module includes auxiliary power supplies U1 and U19. The auxiliary power supply U1 includes an input end, a first output end, a second output end, a third output end and a fourth output end; the positive pole J1 of the first power supply is connected to the positive pole of the input end of the auxiliary power supply U1 through a diode D2. The first branch of the negative pole of the diode D2 is connected to the positive pole of the input end of the auxiliary power supply U1; the negative pole of the input end of the auxiliary power supply U1 is connected to the first branch of the negative pole of the first power supply; the positive pole of the input end of the auxiliary power supply U19 is connected to the second branch of the negative pole of the diode D2, and the negative pole of the input end of the auxiliary power supply U19 is connected to the second branch of the negative pole of the first power supply end.

3. The buck-boost bidirectional inverter circuit according to claim 2, wherein: The bidirectional voltage - stabilizing module includes a polarized capacitor C6 and a non - polarized capacitor C9. The polarized capacitor C6 and the non - polarized capacitor C9 are connected across the positive and negative poles of the first power supply, and the positive pole of the polarized capacitor C6 is connected to the positive pole J1 of the first power supply; The bidirectional voltage stabilizing module further includes half-bridge drivers U2 and U3. The power input ends of half-bridge drivers U2 and U3 are connected in parallel and then connected to the first output end of the auxiliary power supply. The signal input ends of half-bridge drivers U2 and U3 are respectively connected to the driving unit. The first output end of half-bridge driver U2 is connected to the G pole of MOS transistor Q1, and the second output end of half-bridge driver U2 is connected to the G pole of Q9. The first output end of half-bridge driver U3 is connected to the G pole of MOS transistor Q2, and the second output end of half-bridge driver U3 is connected to the G pole of MOS transistor Q10. The D pole of MOS transistor Q1 is connected to the second branch of the first power supply side through resistor R1, and the first branch of the S pole of MOS transistor Q1 is connected to the D pole of MOS transistor Q9. The first branch of the S pole of MOS transistor Q9 is connected to the second branch of the S pole of MOS transistor Q17 through resistor R5. The second branch of the S pole of MOS transistor Q9 is connected to the first branch of the S pole of MOS transistor Q10. The first branch of the D pole of MOS transistor Q10 is connected to the S pole of MOS transistor Q2, and the second branch of the D pole of MOS transistor Q10 is connected to the second branch of the S pole of MOS transistor Q1 through inductor L2. The bidirectional voltage stabilizing module further includes a polarized capacitor C7 and a non-polarized capacitor C8. The polarized capacitor C7 and the non-polarized capacitor C8 are connected across the D pole of MOS transistor Q2 and the second branch of the S pole of MOS transistor Q10. The D pole of MOS transistor Q2 and the second branch of the S pole of MOS transistor Q10 are also used to be connected to the first end of the resonant conversion module. The acquisition unit includes acquisition sub-unit U11, acquisition sub-unit U12, and acquisition sub-unit U15. The acquisition sub-unit U11 is used to acquire the voltage across capacitor C9, the acquisition sub-unit U12 is used to acquire the voltage across capacitor C8, and the acquisition sub-unit U15 is used to acquire the voltage across resistor R5.

4. The step-up and step-down bidirectional inverter circuit according to claim 3, wherein: The resonant conversion module includes half-bridge drivers U4, U5, U6, and U7 whose signal input ends are connected to the driving unit. Among them, the power input ends of half-bridge drivers U4 and U5 are connected to the second output end of auxiliary power supply U1. The power input ends of half-bridge drivers U6 and U7 are connected to the third output end of auxiliary power supply U1. The first output end of half-bridge driver U4 is connected to the G pole of MOS transistor Q3, and the second output end of half-bridge driver U4 is connected to the G pole of Q11. The first output end of half-bridge driver U5 is connected to the G pole of MOS transistor Q4, and the second output end of half-bridge driver U5 is connected to the G pole of MOS transistor Q12. The first output end of half-bridge driver U6 is connected to the G pole of MOS transistor Q5, and the second output end of half-bridge driver U6 is connected to the G pole of Q13. The first output end of half-bridge driver U7 is connected to the G pole of MOS transistor Q6, and the second output end of half-bridge driver U7 is connected to the G pole of Q14. The first branch of the D pole of MOS transistor Q3 is connected to the D pole of MOS transistor Q2, and the second branch of the D pole of MOS transistor Q3 is connected to the D pole of MOS transistor Q4; the first branch of the S pole of MOS transistor Q3 is connected to the D pole of MOS transistor Q11; the first branch of the S pole of MOS transistor Q11 is connected to the second branch of MOS transistor Q10 through resistor R6; the second branch of the S pole of MOS transistor Q11 is connected to the S pole of MOS transistor Q12 and then grounded; the first branch of the D pole of MOS transistor Q12 is connected to the S pole of MOS transistor Q4, and the second branch of the D pole of MOS transistor Q12 is connected to one end of the low-voltage side of transformer T1, and the other end of the low-voltage side of transformer T1 is connected to the second branch of the S pole of MOS transistor Q3; One end of the high-voltage side of transformer T1 is connected to the first branch of the S pole of MOS transistor Q5 through the series-connected capacitor C1 and inductor L1; the second branch of the S pole of MOS transistor Q5 is connected to the D pole of MOS transistor Q13, and the first branch of the S pole of MOS transistor Q13 is connected to the S pole of MOS transistor Q14; the first branch of the D pole of MOS transistor Q14 is connected to the other end of the high-voltage side of transformer T1, and the second branch of the D pole of MOS transistor Q14 is connected to the S pole of MOS transistor Q6; the first branch of the D pole of MOS transistor Q6 is connected to the D pole of MOS transistor Q5, and the second branch of the D pole of MOS transistor Q6 and the second branch of the S pole of MOS transistor Q14 are used to connect to the bidirectional inverter module, and a non-polar capacitor C4 and a polar capacitor C2 are also connected in parallel between the second branch of the D pole of MOS transistor Q6 and the second branch of the S pole of MOS transistor Q14, and the positive pole of the polar capacitor C2 is connected to the second branch of the D pole of MOS transistor Q6; The acquisition unit further includes an acquisition sub-unit U13, an acquisition sub-unit U16 and an acquisition sub-unit U20; the acquisition sub-unit U13 is used to acquire the voltage across resistor R6; The acquisition sub-unit U16 is used to acquire the voltage across capacitor C4, and the acquisition sub-unit U20 is used to acquire the current on the high-voltage side of transformer T1; The positive and negative poles of the output end of the auxiliary power supply U19 are respectively connected to the D pole of MOS transistor Q6 and the S pole of MOS transistor Q14.

5. The step-up and step-down bidirectional inverter circuit according to claim 4, wherein: The bidirectional inverter module includes a half-bridge driver U8 and a half-bridge driver U9; the power input ends of the half-bridge driver U8 and the half-bridge driver U9 are connected to the fourth output end of the first auxiliary power supply U1; the signal input ends of the half-bridge driver U8 and the half-bridge driver U9 are connected to the drive unit, the first output end of the half-bridge driver U8 is connected to the G pole of MOS transistor Q7, and the second output end of the half-bridge driver U8 is connected to the G pole of MOS transistor Q15; the first output end of the half-bridge driver U9 is connected to the G pole of MOS transistor Q8, and the first output end of the half-bridge driver U9 is connected to the G pole of MOS transistor Q16; The first branch of the D pole of MOS transistor Q7 is connected to the second branch of the D pole of MOS transistor Q6. The second branch of the D pole of MOS transistor Q7 is connected to the D pole of MOS transistor Q8. The first branch of the S pole of MOS transistor Q8 is connected to the D pole of MOS transistor Q16. The first branch of the S pole of MOS transistor Q16 is connected to the S pole of Q15. The second branch of the S pole of MOS transistor Q16 is connected to the second branch of the S pole of MOS transistor Q14. The first branch of the D pole of MOS transistor Q15 is connected to the S pole of MOS transistor Q7. The second branch of the D pole of MOS transistor Q15 is connected to one end of the first winding of common mode inductor T2. A resistor R2 and a resistor R3 are connected in series at the other end of the first winding, and then connected to one end of the first winding of common mode inductor T3. One end of the second winding of common mode inductor T3 is connected to one end of the second winding of common mode inductor T2. The other end of the second winding of common mode inductor T2 is connected to the second branch of the S pole of MOS transistor Q8. A capacitor C5 is connected across between resistor R2 and R3 and between the second winding of common mode inductor T2 and the second winding of common mode inductor T3. The other end of the first winding of common mode inductor T3 is connected to the first terminal J2 of the second power supply. The other end of the second winding of common mode inductor T3 is connected to the second terminal J3 of the second power supply. A capacitor C3 is connected across between the first terminal J2 and the second terminal J3. The acquisition unit further includes acquisition sub-unit U14, acquisition sub-unit U17, acquisition sub-unit U18 and acquisition sub-unit U23. The acquisition sub-unit U14 is used to acquire the voltage input or output by the common mode inductor T3. The acquisition sub-unit U17 is used to acquire the voltage across resistor R2. The acquisition sub-unit U18 is used to acquire the voltage across resistor R3.

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