Dual-transformer series alternating inverter circuit and inverter device

Abstract

The present application relates to the technical field of circuits, and discloses a dual-transformer series alternating inverter circuit and an inverter device. The inverter circuit comprises an H-bridge circuit, a main oscillating circuit, a sampling control circuit, and a load circuit; the main oscillating circuit comprises a first transformer and a second transformer; a first output end of the H-bridge circuit is connected to a first end of the first transformer, a second end of the first transformer is connected to a first end of the second transformer, and a second end of the second transformer is connected to a second output end of the H-bridge circuit; a third end of the first transformer is connected to a first end of the load circuit, a fourth end of the first transformer is connected to a fourth end of the second transformer, a third end of the second transformer is connected to a second end of the load circuit, and the fourth end of the second transformer is connected to a third end of the load circuit; and the sampling control circuit is separately connected to the H-bridge circuit and the load circuit and is used for driving the H-bridge circuit and the load circuit, so that a direct current input between a positive electrode and a negative electrode is inverted into an alternating current and then output from the load circuit.

Description

A dual-transformer series alternating inverter circuit and device

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on December 21, 2023, with application number 202311781753.6 and invention name “A dual-transformer series alternating inverter circuit and device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of circuit technology, and in particular to a dual-transformer series alternating inverter circuit and device. Background Art

[0003] Among the various existing power sources, such as batteries, dry cells, and solar cells, all are DC power sources. When these power sources are needed to power an AC load, an inverter circuit is required. The inverter circuit, under the action of a control circuit and an H-bridge circuit, converts the DC power output from the DC power source into an AC output with adjustable frequency and voltage, thereby meeting the power supply requirements of the AC load. In related technologies, H-bridge circuits generally use an LLC quasi-resonant circuit to drive a single high-frequency transformer to achieve the inverter function. However, due to the additional inductor, the inductor has energy loss, which in turn affects the power transfer efficiency and transmission power. Summary of the Invention

[0004] The present application discloses a dual-transformer series alternating inverter circuit, which is used to solve the problems of low power transmission efficiency and low transmission power in existing inverter circuits.

[0005] In a first aspect, an embodiment of the present application provides a dual-transformer series alternating inverter circuit, comprising an H-bridge circuit, a main oscillation circuit, a sampling control circuit, and a load circuit, wherein the main oscillation circuit comprises a first transformer and a second transformer; wherein the power supply end of the H-bridge circuit is connected to the positive pole of a DC power supply, and the ground end of the H-bridge circuit is connected to the negative pole of the DC power supply; the first output end of the H-bridge circuit is connected to the first end of the first transformer, the second end of the first transformer is connected to the first end of the second transformer, and the second end of the second transformer is connected to the second output end of the H-bridge circuit; the third end of the first transformer is connected to the first end of the load circuit, the fourth end of the first transformer is connected to the fourth end of the second transformer, the third end of the second transformer is connected to the second end of the load circuit, and the fourth end of the second transformer is connected to the third end of the load circuit; the sampling control circuit is respectively connected to the H-bridge circuit and the load circuit, and is used to drive the H-bridge circuit and the load circuit, so that the first transformer and the second transformer are alternately in a forward state and a flyback state, respectively, so that the first output electrode and the second output electrode of the load circuit output alternating current.

[0006] In a possible embodiment, the main oscillation circuit also includes a resonant capacitor connected in series with the first transformer and the second transformer, the resonant capacitor being composed of x target capacitors connected in parallel, where x is an integer greater than or equal to 1, and the capacity of the target capacitor is equal to a preset threshold; wherein the first end of the resonant capacitor is connected to the second end of the first transformer, and the second end of the resonant capacitor is connected to the first end of the second transformer.

[0007] In a possible embodiment, an H-bridge circuit includes a first switching tube, a second switching tube, a third switching tube, and a fourth switching tube; wherein the source of the first switching tube is connected to the drain of the third switching tube, and a first output end is provided on the connection line formed; the source of the second switching tube is connected to the drain of the fourth switching tube, and a second output end is provided on the connection line formed; the drain of the first switching tube is connected to the drain of the second switching tube, and a positive connection point is provided on the connection line formed; the source of the third switching tube is connected to the source of the fourth switching tube, and a negative connection point is provided on the connection line formed; and the gate electrodes of the first switching tube, the second switching tube, the third switching tube, and the fourth switching tube are respectively connected to a sampling controller.

[0008] In a possible embodiment, the load circuit includes a fifth switching tube, a sixth switching tube, a seventh switching tube, an eighth switching tube, a first capacitor, and a second capacitor; wherein the source of the fifth switching tube is connected to the source of the sixth switching tube; the source of the seventh switching tube is connected to the source of the eighth switching tube; the drain of the sixth switching tube is connected to the first end of the first capacitor, and a first output electrode is provided on the connection line formed; the second end of the first capacitor is connected to the first end of the second capacitor; the drain of the eighth switching tube is connected to the second end of the second capacitor, and a second output electrode is provided on the connection line formed; the gate electrodes of the fifth, sixth, seventh, and eighth switching tubes are connected to the first end of the second capacitor; , respectively connected to the sampling control circuit; the drain of the fifth switching tube is connected to the third end of the first transformer, the drain of the seventh switching tube is connected to the third end of the second transformer, the fourth end of the first transformer is connected to the fourth end of the second transformer, and the connection point formed is connected to the load circuit to the connection line between the second end of the first capacitor and the first end of the second capacitor; or, the drain of the fifth switching tube is connected to the fourth end of the first transformer, the drain of the seventh switching tube is connected to the fourth end of the second transformer, the third end of the first transformer is connected to the third end of the second transformer, and the connection point formed is connected to the load circuit to the connection line between the second end of the first capacitor and the first end of the second capacitor.

[0009] In a possible embodiment, a first current sensor is provided at the second output end of the H-bridge circuit; when the third end of the first transformer is connected to the third end of the second transformer, or the fourth end of the first transformer is connected to the fourth end of the second transformer, a second current sensor is provided on the connection line between the formed connection point and the load circuit; a third current sensor is provided at the ground end of the H-bridge circuit; the first current sensor, the second current sensor, and the third current sensor are respectively connected to the sampling control circuit; wherein the first current sensor is used to sample the oscillating current amplitude signal, the second current sensor is used to sample the current amplitude signal of each of the fifth switching tube, the sixth switching tube, the seventh switching tube, and the eighth switching tube, and the third current sensor is used to sample the total current amplitude signal when the first switching tube, the second switching tube, the third switching tube, and the fourth switching tube are in operation.

[0010] In a possible embodiment, the preset points sampled by the sampling control circuit include: a first current sensor, a second current sensor, a third current sensor, the third end and the fourth end of the first transformer, the third end of the second transformer, the first end of the first capacitor, the first end and the second end of the second capacitor; the sampling control circuit outputs a pulse width signal modulated according to a waveform function based on the current or voltage signal of the preset points and the power output requirements of the first output electrode and the second output electrode to control the operation of the first switch tube, the second switch tube, the third switch tube and the fourth switch tube, and the power pulse width output by the forward transformer is used as a synchronization signal to control the operation of the fifth switch tube, the sixth switch tube, the seventh switch tube and the eighth switch tube.

[0011] In one possible embodiment, the sampling control circuit is configured to: generate a pulse signal by changing the sinusoidal modulation pulse width, modulation period, and phase shift timing based on respective current amplitude signals of the first, second, third, fourth, fifth, sixth, seventh, and eighth switching transistors, the current amplitude signal of the main oscillator circuit, the sampled voltage amplitude signals at various points in the load circuit, and the transmission power requirement for generating a specified waveform function; and output the pulse signal to the gates of the first, second, third, and fourth switching transistors, respectively, to cause the H-bridge circuit to cyclically operate according to a preset operating mode; and synchronously control the gates of the fifth, sixth, seventh, and eighth switching transistors based on the pulse power timing output to the first and second transformers, so that when the dual-transformer series alternating inverter circuit cyclically operates, the first and second transformers alternately operate in forward and flyback operating modes, ensuring that the first, second, third, fourth, fifth, sixth, seventh, and eighth switching transistors all enter a conducting state when their respective body diodes are forward conducting.

[0012] In a possible embodiment, the preset operating modes include operating mode 1, operating mode 2, operating mode 3, operating mode 4, operating mode 5, operating mode 6, operating mode 7, and operating mode 8. Operating mode 1 is: the first switch tube and the fourth switch tube are in the on state, and the second switch tube and the third switch tube are in the off state. In operating mode 1, if the fifth switch tube and the sixth switch tube are in the off state, the first transformer is in the flyback state, and the seventh switch tube and the eighth switch tube are in the on state, the second transformer is in the forward state, and power is output to the load circuit through the second transformer. If the fifth switch tube and the sixth switch tube are in the on state, the first transformer is in the forward state, and power is output to the load circuit through the first transformer, and the seventh switch tube and the eighth switch tube are in the off state, and the second transformer is in the flyback state. When the fifth switch tube and the sixth switch tube are in the on state, the first output electrode has a positive voltage; when the seventh switch tube and the eighth switch tube are in the on state, the second output electrode has a positive voltage.

[0013] In a possible embodiment, operating mode 2 is as follows: the first switch tube changes from the on state to the off state, the fourth switch tube remains in the on state, and the second and third switch tubes remain in the off state; in operating mode 2, the primary inductance freewheeling characteristics of the transformer in the first transformer and the second transformer that is in the flyback state in operating mode 1 cause current to flow through the body diode of the third switch tube and turn it on. The third switch tube turns on when the voltage drop between the drain and the source is equal to the forward voltage drop of the body diode of the third switch tube. At this time, the third switch tube changes from the off state to the on state, reducing the freewheeling loss of the body diode of the third switch tube, and entering operating mode 3.

[0014] In a possible embodiment, operating mode three is: the third switch tube and the fourth switch tube are in the on state, and the first switch tube and the second switch tube remain in the off state; in operating mode three, the resonant current of the main oscillation circuit forms a closed loop through the third switch tube and the fourth switch tube.

[0015] In a possible embodiment, operating mode four is as follows: the fourth switch tube changes from the on state to the off state, the third switch tube remains in the on state, and the first switch tube and the second switch tube remain in the off state; in operating mode four, the freewheeling characteristics of the primary inductances of the first transformer and the second transformer cause the body diode of the second switch tube to conduct freewheeling current, and the second switch tube conducts when the voltage drop between the drain and source of the second switch tube is equal to the forward voltage drop of the body diode of the second switch tube. At this time, the second switch tube changes from the off state to the on state, reducing the freewheeling loss of the body diode of the second switch tube, and entering operating mode five.

[0016] In a possible embodiment, operating mode five is as follows: the second switch tube and the third switch tube are in the on state, and the first switch tube and the fourth switch tube remain in the off state; in operating mode five, if the fifth switch tube and the sixth switch tube are in the off state, the first transformer is in the flyback state, and the seventh switch tube and the eighth switch tube are in the on state, the second transformer is in the forward state, and power is output to the load circuit through the second transformer; if the fifth switch tube and the sixth switch tube are in the on state, the first transformer is in the forward state, power is output to the load circuit through the first transformer, and the seventh switch tube and the eighth switch tube are in the off state, and the second transformer is in the flyback state; wherein, when the fifth switch tube and the sixth switch tube are in the on state, the first output electrode has a negative voltage, and when the seventh switch tube and the eighth switch tube are in the on state, the second output electrode has a negative voltage.

[0017] In a possible embodiment, operating mode six is ​​as follows: the third switch tube changes from the on state to the off state, the second switch tube remains in the off state, and the first switch tube and the fourth switch tube remain in the off state; in operating mode six, the freewheeling characteristics of the primary inductance of the transformer in the first transformer and the second transformer that is in the flyback state in the previous operating mode cause the body diode of the first switch tube to conduct and freewheel, and the first switch tube is turned on when the voltage between the drain and the source is equal to the forward voltage of the body diode of the first switch tube, thereby reducing the freewheeling loss of the body diode of the first switch tube, and entering the operating mode seven.

[0018] In a possible embodiment, working mode seven is: the first switch tube and the second switch tube are in the on state, and the third switch tube and the fourth switch tube remain in the off state; in working mode seven, the resonant current of the main oscillation circuit forms a closed loop through the first switch tube and the second switch tube.

[0019] In a possible embodiment, operating mode eight is as follows: the second switch tube changes from the on state to the off state, the first switch tube remains in the on state, and the third and fourth switch tubes remain in the off state; in operating mode eight, the freewheeling characteristics of the primary inductances in the first transformer and the second transformer cause the body diode of the fourth switch tube to conduct freewheeling, wherein when the drain and source of the fourth switch tube are in a zero voltage state, the body diode of the fourth switch tube is forward-conducted, thereby reducing the freewheeling loss of the body diode of the fourth switch tube, and entering operating mode one.

[0020] In a possible embodiment, the sampling control circuit is further used to: adjust the conduction timing of the fifth switching tube, the sixth switching tube, the seventh switching tube, and the eighth switching tube, so that the first transformer and the second transformer operate alternately in the flyback and forward states, and cooperate with the first switching tube, the second switching tube, the third switching tube, and the fourth switching tube so that the main oscillation circuit is in a fully resonant state when operating; wherein, when the first transformer is in the forward state, the second transformer is in the flyback state; when the first transformer is in the flyback state, the second transformer is in the forward state; the fully resonant state is achieved by the primary inductance and resonant capacitance of the transformer in the flyback state of the first transformer or the second transformer, and the transformer in the forward state of the first transformer or the second transformer is used to transfer power.

[0021] In a second aspect, an embodiment of the present application provides an inverter device, comprising any of the above-mentioned dual-transformer series alternating inverter circuits.

[0022] The beneficial technical effects of the present application are as follows: An embodiment of the present application provides a dual-transformer series alternating inverter circuit and device, the circuit including an H-bridge circuit, a main oscillator circuit, a sampling control circuit, and a load circuit, wherein the main oscillator circuit includes transformer 1 and transformer 2. The H-bridge circuit and the load circuit are driven by a sampling controller, so that the first transformer and the second transformer are alternately in a forward state and a flyback state, respectively, so that the first output electrode and the second output electrode of the load circuit output AC power, thereby achieving inversion of the DC power supply. In addition, since the first transformer and the second transformer are alternately in a forward state and a flyback state, respectively, the power output by the first output electrode and the second output electrode is the sum of the powers of the two transformers, and there is no inductive energy loss, thereby improving power transfer efficiency and transmission power.

[0023] Figures in the specification

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] FIG1 is a schematic diagram of a dual-transformer series alternating inverter circuit provided in an embodiment of the present application.

[0026] FIG2 is a schematic diagram of another dual-transformer series alternating inverter circuit provided in an embodiment of the present application.

[0027] FIG3 is a schematic diagram of another dual-transformer series alternating inverter circuit provided in an embodiment of the present application.

[0028] FIG4A is a schematic diagram of another dual-transformer series alternating inverter circuit provided in an embodiment of the present application.

[0029] FIG4B is a schematic diagram of another dual-transformer series alternating inverter circuit provided in an embodiment of the present application.

[0030] FIG5A is a schematic diagram of another dual-transformer series alternating inverter circuit provided in an embodiment of the present application.

[0031] FIG5B is a schematic diagram of another dual-transformer series alternating inverter circuit provided in an embodiment of the present application.

[0032] FIG6A is an example diagram of a dual-transformer series alternating inverter circuit provided in an embodiment of the present application.

[0033] FIG6B is an example diagram of another dual-transformer series alternating inverter circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail with reference to the accompanying drawings. The specific circuits in the circuit embodiments can also be applied to the device embodiments. It should be noted that in the description of the present application, "multiple" is understood as "at least two". "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist at the same time, and B exists alone. A is connected to B, which can represent the following two situations: A is directly connected to B and A is connected to B through C. In addition, in the description of the present application, words such as "first" and "second" are only used to distinguish the purpose of description, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order.

[0035] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0036] It should be noted that the ends 1, 2, 3, and 4 of the components in the following figures are used to represent the first end, the second end, the third end, and the fourth end of the component, respectively, and will not be repeated in the following content.

[0037] As shown in FIG1 , a dual-transformer series alternating inverter circuit provided in an embodiment of the present application includes an H-bridge circuit 101 , a main oscillator circuit 102 , a sampling control circuit 103 , and a load circuit 104 . The main oscillator circuit 102 includes a first transformer 102A and a second transformer 102B.

[0038] In FIG1 , the power supply terminal of the H-bridge circuit 101 is connected to the positive electrode of the DC power supply, and the ground terminal of the H-bridge circuit 101 is connected to the negative electrode of the DC power supply; the first output terminal L of the H-bridge circuit 101 is connected to the first terminal of the first transformer 102A, the second terminal of the first transformer 102A is connected to the first terminal of the second transformer 102B, and the second terminal of the second transformer 102B is connected to the second output terminal R of the H-bridge circuit 101; the third terminal of the first transformer 102A is connected to the first terminal of the load circuit 104, the fourth terminal of the first transformer 102A is connected to the fourth terminal of the second transformer 102B, and the second terminal of the second transformer 102B is connected to the second output terminal R of the H-bridge circuit 101; The third end of the transformer 102B is connected to the second end of the load circuit 104, and the fourth end of the second transformer 102B is connected to the third end of the load circuit 104. The sampling control circuit 103 is connected to the H-bridge circuit 101 and the load circuit 104, respectively, and is used to drive the H-bridge circuit 101 and the load circuit 104 so that the first transformer 102A and the second transformer 102B are alternately in the forward state and the flyback state, respectively, so that the direct current between the positive and negative poles of the direct current power supply is inverted into alternating current and output from the first output electrode PVa and the second output electrode PVb of the load circuit 104.

[0039] The first transformer 102A and the second transformer 102B alternate between forward and flyback states, respectively. This means that when the first transformer 102A is in the forward state, the second transformer 102B is in the flyback state; and when the first transformer 102A is in the flyback state, the second transformer 102B is in the forward state. Furthermore, as the first transformer alternates between the forward and flyback states, the second transformer 102B also alternates between the flyback and forward states. Consequently, the power output by the first and second output electrodes of the load circuit 104 is between the power outputs of the two transformers, improving power transmission efficiency.

[0040] In a possible embodiment, as shown in FIG2 , the main oscillation circuit 102 further includes a resonant capacitor 201 connected in series with the first transformer 102A and the second transformer 102B. The resonant capacitor 201 is composed of x target capacitors connected in parallel, where x is an integer greater than or equal to 1, and the capacity of the target capacitor is equal to a preset threshold value; wherein the first end of the resonant capacitor 201 is connected to the second end of the first transformer 102A, and the second end of the resonant capacitor is connected to the first end of the second transformer. In this circuit, the first transformer and the second transformer are arranged on both sides of the resonant capacitor, which is a symmetrical balanced design. The resonant capacitor is composed of x small-capacity capacitors connected in parallel, which effectively reduces the internal resistance of the capacitor, increases the current passing through the main oscillation circuit, and reduces the loss and temperature rise caused by the capacitor, thereby improving the current carrying capacity of the series circuit, and thus improving the transmission efficiency of the main oscillation circuit. In the circuit diagram shown in FIG1 , the resonant capacitor can also be eliminated to meet the needs of high-power applications.

[0041] Optionally, as shown in FIG3 , the H-bridge circuit 101 includes a first switch tube 301, a second switch tube 302, a third switch tube 303, and a fourth switch tube 304; wherein the source S pin of the first switch tube 301 is connected to the drain D pin of the third switch tube 303, and the connection line formed is provided with a first output terminal L; the source S pin of the second switch tube 302 is connected to the drain D pin of the fourth switch tube 304, and the connection line formed is provided with a second output terminal R; the drain D pin of the first switch tube 301 is connected to the drain D pin of the second switch tube 302, and the connection line formed is provided with a second output terminal R; A positive connection point is provided on the connection line formed, wherein the positive connection point is connected to the positive electrode of the DC power supply; the source S pin of the third switching tube 303 is connected to the source S pin of the fourth switching tube 304, and a negative connection point is provided on the connection line formed, wherein the negative connection point is connected to the negative electrode of the DC power supply; and the gate G pin of the first switching tube 301, the gate G pin of the second switching tube 302, the gate G pin of the third switching tube 303, and the gate G pin of the fourth switching tube 304 are respectively connected to the sampling controller 103 (the specific connection lines are not shown in FIG3).

[0042] Optionally, as shown in FIG4A and FIG4B, the load circuit 104 includes a fifth switch tube 401, a sixth switch tube 402, a seventh switch tube 403, an eighth switch tube 404, a first capacitor 405, and a second capacitor 406; wherein the source S pin of the fifth switch tube 401 is connected to the source S pin of the sixth switch tube 402; the source S pin of the seventh switch tube 403 is connected to the source S pin of the eighth switch tube 404; the drain D pin of the sixth switch tube 402 is connected to the first end of the first capacitor 405, and the connection line formed is provided with The first output electrode PVA is connected; the second end of the first capacitor 405 is connected to the first end of the second capacitor 406; the drain pin D of the eighth switching tube 404 is connected to the second end of the second capacitor 406, and the second output electrode PVb is provided on the connecting line formed; the gate pin G of the fifth switching tube 401, the gate pin G of the sixth switching tube 402, the gate pin G of the seventh switching tube 403, and the gate pin G of the eighth switching tube 404 are respectively connected to the sampling control circuit 103 (the specific connecting lines are not shown in Figures 4A and 4B).

[0043] 4A , the drain D pin of the fifth switch 401 is connected to the third terminal of the first transformer 102A, the drain D pin of the seventh switch 403 is connected to the third terminal of the second transformer 102B, and the fourth terminal of the first transformer 102A is connected to the fourth terminal of the second transformer 102B. The connection point formed by the connection point and the load circuit 104 is connected to the connection line between the second terminal of the first capacitor 405 and the first terminal of the second capacitor 406. Alternatively, referring to FIG. 4B , the drain D pin of the fifth switch 401 is connected to the fourth terminal of the first transformer 102A, the drain D pin of the seventh switch 403 is connected to the fourth terminal of the second transformer 102B, and the third terminal of the first transformer 102A is connected to the third terminal of the second transformer 102B. The connection point formed by the connection point and the load circuit 104 is connected to the connection line between the second terminal of the first capacitor 405 and the first terminal of the second capacitor 406.

[0044] Optionally, as shown in FIG5A and FIG5B , the second output terminal R of the H-bridge circuit 101 is provided with a first current sensor 501; when the third terminal of the first transformer 102A is connected to the third terminal of the second transformer 102B, or the fourth terminal of the first transformer 102A is connected to the fourth terminal of the second transformer 102B, a second current sensor 502 is provided on the connection line between the formed connection point and the load circuit 104; a third current sensor 503 is provided on the ground terminal of the H-bridge circuit 101; the first current sensor 501 and the second current sensor 502 are connected to each other. The first current sensor 501 is used to sample the oscillation current amplitude signal in the main oscillation circuit; the second current sensor 502 is used to sample the current amplitude signals of the fifth switching tube 401, the sixth switching tube 402, the seventh switching tube 403, and the eighth switching tube 404; and the third current sensor 503 is used to sample the total current amplitude signal when the first switching tube 301, the second switching tube 302, the third switching tube 303, and the fourth switching tube 304 are in operation.

[0045] Optionally, the preset points sampled by the sampling control circuit 103 include: the first current sensor 501, the second current sensor 502, the third current sensor 503, the third and fourth terminals of the first transformer 102A, the third terminal of the second transformer 102B, the first terminal of the first capacitor 405, and the first and second terminals of the second capacitor 406. Based on the current or voltage signals at the preset points and the power output requirements of the first output electrode PVa and the second output electrode PVb, the sampling control circuit 103 outputs a pulse width signal modulated by a waveform function to control the operation of the first switching transistor 301, the second switching transistor 302, the third switching transistor 303, and the fourth switching transistor 304. Furthermore, the power pulse width output by the transformer in the forward state serves as a synchronization signal to control the operation of the fifth switching transistor 401, the sixth switching transistor 402, the seventh switching transistor 403, and the eighth switching transistor 404. It is easy to understand that the preset points sampled by the control circuit 103 are all connected to the sampling controller (specific connection lines are not shown in Figures 5A and 5B).

[0046] In the above circuit, the sampling control circuit 103 is used to generate a pulse signal by changing the sinusoidal modulation pulse width, modulation period, and phase shift timing according to the current amplitude signals of the first switching transistor 301, the second switching transistor 302, the third switching transistor 303, the fourth switching transistor 304, the fifth switching transistor 401, the sixth switching transistor 402, the seventh switching transistor 403, and the eighth switching transistor 404, the current amplitude signal of the main oscillator circuit 102, the sampled voltage amplitude signals at each point in the load circuit 104, and the transmission power requirement for generating a specified waveform, and output the pulse signal to the gate G pins corresponding to the first switching transistor 301, the second switching transistor 302, the third switching transistor 303, and the fourth switching transistor 304, respectively, so as to enable the H-bridge circuit 101 to generate a pulse signal. The circuit operates cyclically according to a preset operating mode; and according to the pulse power timing output to the first transformer 102A and the second transformer 102B, the gate G pins corresponding to the fifth switch 401, the sixth switch 402, the seventh switch 403, and the eighth switch 404 are synchronously controlled. When the dual-transformer series alternating inverter circuit operates cyclically, the first transformer 102A and the second transformer 102B operate alternately in forward and flyback conditions, ensuring that the first switch 301, the second switch 302, the third switch 303, the fourth switch 304, the fifth switch 401, the sixth switch 402, the seventh switch 403, and the eighth switch 404 all operate in a conductive state when their respective body diodes are in forward conduction.

[0047] In the above process, the preset working modes include working mode 1, working mode 2, working mode 3, working mode 4, working mode 5, working mode 6, working mode 7, and working mode 8.

[0048] Optionally, the first working mode is: the first switch tube 301 and the fourth switch tube 304 are in the on state, and the second switch tube 302 and the third switch tube 303 are in the off state;

[0049] In the embodiment of the present application, the fifth and sixth switches 401 and 402 function as one switch group, and the seventh and eighth switches 403 and 404 function as another switch group. These two switch groups cannot be turned on or off simultaneously. Specifically, when the fifth and sixth switches 401 and 402 are turned on, the seventh and eighth switches 403 and 404 are turned off. When the fifth and sixth switches 401 and 402 are turned off, the seventh and eighth switches 403 and 404 are turned on.

[0050] Based on this, in operating mode 1, the DC power supply charges the main oscillator circuit 102 via the first switch 301 and the fourth switch 304. The current flows sequentially from the first end of the first transformer 102A, to the second end of the first transformer 102A, to the first end of the resonant capacitor 201, to the second end of the resonant capacitor 201, to the first end of the second transformer 102B, and finally to the second end of the second transformer 102B. At this time, if the fifth switch 401 and the sixth switch 402 are off, the first transformer 102A is in a flyback state. Since the fifth and sixth switches 401 and 402, and the seventh and eighth switches 403 and 404 cannot be turned on or off simultaneously, the seventh and eighth switches 403 and 404 are turned on, and the second transformer 102B is in a forward state. Power is then output to the load circuit 104 via the second transformer 102B. Similarly, if the fifth and sixth switching transistors 401 and 402 are in the on-state, the first transformer 102A is in the forward state, and power is output to the load circuit through the first transformer. At this time, since the fifth and sixth switching transistors 401 and 402, and the seventh and eighth switching transistors 403 and 404 cannot be turned on or off at the same time, the seventh and eighth switching transistors 403 and 404 are in the off-state, and the second transformer 102B is in the flyback state. When the fifth and sixth switching transistors 401 and 402 are in the on-state, the first output electrode PVa has a positive voltage; when the seventh and eighth switching transistors 403 and 404 are in the on-state, the second output electrode PVb has a positive voltage.

[0051] Optionally, working mode two is: the first switch tube 301 changes from the on state to the off state, the fourth switch tube 304 remains in the on state, and the second switch tube 302 and the third switch tube 303 remain in the off state; in working mode two, the primary inductance freewheeling characteristics of the transformer in the first transformer 102A and the second transformer 102B that is in the flyback state in working mode one causes the body diode of the third switch tube 303 to pass current and be turned on, and the third switch tube 303 is turned on when the voltage drop between the drain pin D and the source pin S is equal to the forward voltage drop of the body diode of the third switch tube 303. At this time, the third switch tube 303 changes from the off state to the on state, reducing the freewheeling loss of the body diode of the third switch tube 303, and entering working mode three.

[0052] Optionally, working mode three is: the third switch tube 303 and the fourth switch tube 304 are in the on state, and the first switch tube 301 and the second switch tube 302 remain in the off state; in working mode three, the resonant current of the main oscillation circuit 102 forms a closed loop through the third switch tube 303 and the fourth switch tube 304.

[0053] Optionally, working mode four is: the fourth switch tube 304 changes from the on state to the off state, the third switch tube 303 remains in the on state, and the first switch tube 301 and the second switch tube 302 remain in the off state; in working mode four, the freewheeling characteristics of the primary inductance of the first transformer 102A and the second transformer 102B cause the body diode of the second switch tube 302 to conduct and freewheel, and the second switch tube 302 is conducted when the voltage drop between the drain pin D and the source pin S is equal to the forward voltage drop of the body diode of the second switch tube 302. At this time, the second switch tube 302 changes from the off state to the on state, reducing the freewheeling loss of the body diode of the second switch tube 302, and entering working mode five.

[0054] Optionally, working mode five is: the second switch tube 302 and the third switch tube 303 are in the on state, and the first switch tube 301 and the fourth switch tube 304 remain in the off state; in working mode five, the DC power supply charges the main oscillation circuit 102 through the second switch tube 302 and the third switch tube 303, and the current flows to: the second end of the second transformer 102B, the first end of the second transformer 102B, the second end of the resonant capacitor 201, the first end of the resonant capacitor 201, the second end of the first transformer 102A, and the first end of the second transformer 102A. At this time, if the fifth switch tube 401 and the sixth switch tube 402 are in the off state, the first transformer 102A is in the flyback state, and because the fifth switch tube 401 and the sixth switch tube 402 and the seventh switch tube 403 and the eighth switch tube 404 cannot be turned on or off at the same time, the seventh switch tube 403 and the eighth switch tube 404 are in the on state, the second transformer 102B is in the forward state, and power is output to the load circuit 104 through the second transformer 102B. Similarly, if the fifth and sixth switches 401 and 402 are in the on-state, the first transformer 102A is in the forward state, and power is output to the load circuit through the first transformer 102A. Since the fifth and sixth switches 401 and 402, and the seventh and eighth switches 403 and 404 cannot be turned on or off at the same time, the seventh and eighth switches 403 and 404 are in the off-state, and the second transformer 102B is in the flyback state. When the fifth and sixth switches 401 and 402 are in the on-state, the first output electrode PVa has a negative voltage; when the seventh and eighth switches 403 and 404 are in the on-state, the second output electrode PVb has a negative voltage.

[0055] Optionally, working mode six is: the third switch tube 303 changes from the on state to the off state, the second switch tube 302 remains in the off state, and the first switch tube 301 and the fourth switch tube 304 remain in the off state; in working mode six, the freewheeling characteristics of the primary inductance of the transformer in the first transformer 102A and the second transformer 102B that is in the flyback state in the previous working mode cause the body diode of the first switch tube 301 to conduct and freewheel, and the first switch tube 301 is turned on when the voltage between the drain pin D and the source pin S is equal to the forward voltage of the body diode of the first switch tube 301, thereby reducing the freewheeling loss of the body diode of the first switch tube 301, and entering the said working mode seven.

[0056] Optionally, working mode seven is: the first switch tube 301 and the second switch tube 302 are in the on state, and the third switch tube 303 and the fourth switch tube 304 remain in the off state; in working mode seven, the resonant current of the main oscillation circuit 102 forms a closed loop through the first switch tube 301 and the second switch tube 302.

[0057] Optionally, working mode eight is: the second switch tube 302 changes from the on state to the off state, the first switch tube 301 remains in the on state, and the third switch tube 303 and the fourth switch tube 304 remain in the off state; in working mode eight, the freewheeling characteristics of the primary inductance in the first transformer 102A and the second transformer 102B cause the body diode of the fourth switch tube 304 to conduct and freewheel, wherein, when the voltage between the drain pin D and the source pin S of the fourth switch tube 304 is in a zero voltage state, the body diode of the fourth switch tube 304 is forward-conducted, reducing the freewheeling loss of the body diode of the fourth switch tube 304, and entering working mode one.

[0058] The aforementioned operating modes 1, 2, 3, 4, 5, 6, 7, and 8 are cycled sequentially, with each cycle forming a power transmission cycle. This inverts DC power into AC power and ensures efficient power transmission. During this process, each switch operates in a state where the voltage Vds between the drain and source is zero, effectively reducing switching losses.

[0059] During this process, any of the first, second, third, fourth, and eighth switches 301, 302, 303, 304, 401, 402, 403, and 404 switches always operate in the zero-crossing conduction state, ensuring the lowest-loss turn-on condition and minimizing the current ringing amplitude at the moment of turn-on, significantly reducing radiated interference. Furthermore, by adjusting the dead time, the switch that is about to be turned on in the oscillation loop is controlled to enter the zero-crossing switching state.

[0060] In the above circuit, the sampling control circuit 103 is further configured to adjust the conduction timing of the fifth switching transistor 401, the sixth switching transistor 402, the seventh switching transistor 403, and the eighth switching transistor 404, so that the first transformer 102A and the second transformer 102B operate alternately in flyback and forward modes. Specifically, when the first transformer 102A is in the flyback mode, the second transformer 102B is in the forward mode; and when the first transformer 102A is in the flyback mode, the second transformer 102B is in the forward mode. The first transformer 102A and the second transformer 102B both alternate between the flyback and forward modes. During this process, the first switching tube 301, the second switching tube 302, the third switching tube 303, and the fourth switching tube 304 cooperate to ensure that the main oscillation circuit 102 is in a fully resonant state when operating. Specifically, when the first transformer 102A is in a forward state, the second transformer 102B is in a flyback state; when the first transformer 102A is in a flyback state, the second transformer 102B is in a forward state. The fully resonant state is achieved by the primary inductance and resonant capacitance of the first transformer 102A or the second transformer 102B in the flyback state, and the transformer in the forward state of the first transformer 102A or the second transformer 102B is used to transfer power.

[0061] Optionally, the sampling control circuit 103 is further configured to control the on and off states of the fifth switching tube 401, the sixth switching tube 402, the seventh switching tube 403, and the eighth switching tube 404, so that the first transformer 102A and the second transformer 102B alternately operate in a forward state and a flyback state; wherein, when the fifth switching tube 401 and the sixth switching tube 402 are on, and the seventh switching tube 403 and the eighth switching tube 404 are off, the first transformer 102A is in a forward state to provide power, and the second transformer 102B is in a flyback state, the magnetic core is energized, and participates in resonance; when the fifth switching tube 401 and the sixth switching tube 402 are off, and the seventh switching tube 403 and the eighth switching tube 404 are on, the second transformer 102B is in a forward state to provide power, and the first transformer 102A is in a flyback state, the magnetic core is energized, and participates in oscillation; when either the first transformer 102A or the second transformer 102B is in the flyback state, resonance occurs between the primary inductance and the resonant capacitor of the transformer.

[0062] In a possible embodiment, when the primary inductance of the transformer in the flyback state in the first transformer 102A and the second transformer 102B oscillates with the resonant capacitor, the sampling control circuit 103 controls the on-pulse width, PWM period, dead time, and phase timing of the gate G pins of the first switching transistor 301, the second switching transistor 302, the third switching transistor 303, and the fourth switching transistor 304, respectively, so that the first switching transistor 301, the second switching transistor 302, the third switching transistor 303, and the fourth switching transistor 304 are all in the on-state when their body diodes are conducting, and the main oscillation circuit is in a fully resonant state.

[0063] In a possible embodiment, when the fifth switch tube 401 and the sixth switch tube 402 are in the on state and the seventh switch tube 403 and the eighth switch tube 404 are in the off state, the first transformer 102A is in the forward state, and the output power current charges the first capacitor 405 through the fifth switch tube 401 and the sixth switch tube 402; when the fifth switch tube 401 and the sixth switch tube 402 are in the off state and the seventh switch tube 403 and the eighth switch tube 404 are in the on state, the second transformer 102B is in the forward state, and the output power current charges the second capacitor 406 through the seventh switch tube 403 and the eighth switch tube 404.

[0064] In normal operating conditions, the switching timing of the fifth, sixth, seventh, and eighth switches 401, 402, 403, and 404 is consistent with the output pulse of the forward transformer. When the conduction period of the fifth and sixth switches 401, 402 is consistent with the conduction period of the first and fourth switches 301, 304, the voltage of the first output electrode PVA is greater than the voltage of the second output electrode PVb, so that the output voltage and current waveforms of the load circuit 104 are in the positive half-cycle of the AC power. When the conduction period of the fifth and sixth switches 401, 402 is consistent with the conduction period of the second and third switches 402, 403, the voltage of the second output electrode PVb is greater than the voltage of the first output electrode PVA, so that the output voltage and current waveforms of the load circuit 104 are in the negative half-cycle of the AC power.

[0065] In one possible embodiment, when each of the fifth switch tube 401, the sixth switch tube 402, the seventh switch tube 403, and the eighth switch tube 404 is turned on, the tube voltage drop of the turned-on switch tube is clamped by the body diode of the switch tube, so that the switch tube is in the body diode forward conduction state each time it is turned on. As a result, the switch tube is turned on with a minimum surge current value under the control of the sampling control circuit, which greatly reduces the current ringing phenomenon when the switch tube is turned on and reduces the loss when the switch tube is turned on.

[0066] In one possible embodiment, oscillation energy is stored in the transformer in the flyback state of the first transformer 102A and the second transformer 102B, and the oscillation energy is transferred to the load circuit 104 in the next alternating cycle. That is, when the flyback state is switched to the forward state, the oscillation energy is transferred to the load circuit 104, thereby minimizing the oscillation loss of the first transformer 102A and the second transformer 102B. All power devices operate in an optimal ultra-low loss operating condition, so that the dual-transformer series alternating inverter circuit can achieve extremely high transmission efficiency and a transmission power that is more than 1.5 times that of a single transformer in the forward state.

[0067] In one possible embodiment, the first transformer 102A or the second transformer 102B operates in a forward state or a flyback state, and when the voltage of the first output electrode PVA is greater than the voltage of the second output electrode PVb, the sine wave output by the load circuit 104 is in a positive half-cycle, or when the voltage of the first output electrode is less than the voltage of the second output electrode, the sine wave output by the load circuit is in a negative half-cycle. Both of these are achieved by the fifth switch 401, the sixth switch 402, the seventh switch 403, and the eighth switch 404 coordinating with the timing of the first switch 301, the second switch 302, the third switch 303, and the fourth switch 304. The fifth switch 401 and the sixth switch 402, and the seventh switch 403 and the eighth switch 404 are sequentially turned on to achieve bidirectional synchronous rectification output characteristics, so that the output power of the first output electrode PVa and the second output electrode PVb exhibits fluctuation characteristics of at least one of a sine function waveform, an exponential function waveform, a square wave waveform, and a trigonometric function waveform according to the characteristics of pulse width modulation.

[0068] In a possible embodiment, when the potential of the first output electrode PVA is higher than the potential of the second output electrode PVA and the output AC voltage is in the positive half cycle, the conduction timing of the fifth switch tube 401 and the sixth switch tube 402 is as follows: the fifth switch tube 401 is turned on first, and after the body diode of the sixth switch tube 402 is turned on, the sixth switch tube 402 is changed from the off state to the on state, so that the sixth switch tube operates in a state where the body diode between the drain and the source is forward-conducted and then turned on, and the first capacitor 405 does not have current backflow, and the fifth switch tube 401 that is turned on first operates at zero voltage zero The current state is turned on; when the potential of the first output electrode PVa is lower than the potential of the second output electrode PVb and the output AC voltage is in the negative half cycle, the conduction timing of the fifth switch tube 401 and the sixth switch tube 402 when they are turned on is: the sixth switch tube 402 is turned on first, and after the body diode of the fifth switch tube is turned on, the fifth switch tube 401 is changed from the off state to the on state, so that the fifth switch tube 401 works in the state of conduction when the drain and the source are in the forward direction, and the first capacitor 405 does not have current backflow, and the sixth switch tube 405 that is turned on first is turned on in the zero voltage and zero current state.

[0069] In a possible embodiment, when the seventh switch tube 403 and the eighth switch tube 404 are turned on, when the potential of the first output electrode Pva is higher than the potential of the second output electrode PVb and the output AC voltage is in the positive half cycle, the turn-on timing of the seventh switch tube 403 and the eighth switch tube 404 is as follows: the eighth switch tube 404 is turned on first, and after the body diode of the seventh switch tube 403 is turned on, the seventh switch tube 403 is changed from the off state to the on state, so that the seventh switch tube 403 enters the on state when the body diode forward voltage is reached between the drain and the source, and the second capacitor 406 does not have current backflow, and the eighth switch tube 404 that is turned on first is turned on first. 4 operates in a zero voltage and zero current state and is turned on; when the potential of the first output electrode Pva is lower than the potential of the second output electrode PVb and the output AC voltage is in a negative half cycle, the turn-on timing of the seventh switch tube 403 and the eighth switch tube 404 is as follows: the seventh switch tube 403 is turned on first, and after the body diode of the eighth switch tube 404 is turned on, the eighth switch tube 404 is changed from the off state to the on state, so that the eighth switch tube 404 operates in a conduction state when the voltage between the drain and the source is the forward voltage of the body diode, and the second capacitor 406 is prevented from having a current backflow, and the seventh switch tube 403 that is turned on first is turned on in the zero voltage and zero current state.

[0070] In a possible embodiment, the first switch tube 301, the second switch tube 302, the third switch tube 303, the fourth switch tube 304, the fifth switch tube 401, the sixth switch tube 402, the seventh switch tube 403, and the eighth switch tube 404 are all MOS switch tubes with body diodes; when the MOS switch tubes are replaced with IGBT switch tubes with body diodes, the collector C of the IGBT switch tube corresponds to the drain D of the MOS switch tube, and the emitter E of the IGBT switch tube corresponds to the source S of the MOS switch tube.

[0071] To further illustrate the technical solution of the present application, as shown in FIG6A or FIG6B, an example diagram of a dual-transformer series alternating inverter circuit provided in an embodiment of the present application is applicable to DC / AC power inverters and inverter-type electronic equipment, and is applied in the field of power electronics. The circuit includes an H-bridge circuit, a main oscillator circuit, a sampling control circuit, and a load circuit. The H-bridge circuit includes switch tubes S1, S2, S3, and S4; the main oscillator circuit includes transformer 1 T1, transformer 2 T2, and a resonant capacitor 201, which is composed of multiple small capacitors connected in parallel; the load circuit includes switch tubes S5, S6, S7, and S8, capacitors C1, and C2; the sampling control circuit collects the current and voltage signals of the dual-transformer series alternating inverter circuit through current sensors L1, L2, and L3.

[0072] In this circuit, the power supply VCC and common ground GND of the H-bridge circuit are connected to a DC power supply, and transformers T1 and T2 are arranged on both sides of the resonant capacitor, forming a symmetrical balanced design. The sampling control circuit collects current and voltage from current sensors L1, L2, L3, terminals 3 and 4 of transformer T1, terminal 3 of transformer T2, terminal 1 of capacitor C1, and terminals 1 and 2 of capacitor C2 to ensure that each switch operates within a safe current and voltage range. Specifically, according to the above-mentioned operating modes 1, 2, 3, 4, 5, 6, 7, and 8, the first and second switching modes are cycled in sequence, so that transformers 1 and 2 alternate between forward and flyback states, thereby outputting AC power between electrodes Pva and PVb. Each cycle is a power transmission cycle, which converts DC power into AC power and effectively transmits power. During this process, each switch operates in a state where the voltage Vds between the drain and source is zero, effectively reducing switching losses.

[0073] In this circuit, the resonant capacitor, consisting of x small-capacity capacitors connected in parallel, effectively reduces the internal resistance of the capacitor, increases the current-carrying capacity of the series circuit, and thus improves the transmission efficiency of the main oscillator circuit. Furthermore, the resonant capacitor can be eliminated to meet the needs of high-power applications. Furthermore, since transformers 1 and 2 alternate between forward and flyback states, respectively, the power output of electrodes Pva and PVb is the sum of the powers of the two transformers, with no inductive energy loss, thereby improving power transfer efficiency and transmission power.

[0074] The present application also provides an inverter device, including any of the above-mentioned dual-transformer series alternating circuits, and realizing its functions. Its principles and technical effects can refer to any of the above-mentioned dual-transformer series alternating circuits, and will not be described in detail here.

[0075] It should be noted that the accompanying drawings are merely examples and are not limitations on the structure of the circuit diagrams. The various circuit diagrams may be in a parallel relationship or a progressive relationship, may be combined with each other, or the circuits in the various circuit diagrams may be combined with reference to each other. The specific combination method is not limited in the embodiments of the present application.

[0076] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0077] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

[0078] This document uses specific examples to illustrate the principles and implementation methods of this application. The description of the above examples is only intended to help understand the method and core concept of this application. At the same time, for those skilled in the art, based on the concept of this application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A dual transformer series alternating inverter circuit, characterized in that: It includes an H-bridge circuit, a main oscillation circuit, a sampling control circuit and a load circuit, wherein the main oscillation circuit includes a first transformer and a second transformer; Wherein, the power supply end of the H-bridge circuit is connected to the positive electrode of the DC power supply, and the ground end of the H-bridge circuit is connected to the negative electrode of the DC power supply; the first output end of the H-bridge circuit is connected to the first end of the first transformer, the second end of the first transformer is connected to the first end of the second transformer, and the second end of the second transformer is connected to the second output end of the H-bridge circuit; the third end of the first transformer is connected to the first end of the load circuit, the fourth end of the first transformer is connected to the fourth end of the second transformer, the third end of the second transformer is connected to the second end of the load circuit, and the fourth end of the second transformer is connected to the third end of the load circuit; The sampling control circuit is connected to the H-bridge circuit and the load circuit respectively, and is used to drive the H-bridge circuit and the load circuit so that the first transformer and the second transformer are alternately in a forward state and a flyback state respectively, so that the first output electrode and the second output electrode of the load circuit output alternating current.

2. The dual transformer series alternating inverter circuit as claimed in claim 1, characterized in that: The main oscillation circuit further includes a resonant capacitor connected in series with the first transformer and the second transformer, the resonant capacitor is composed of x target capacitors connected in parallel, x is an integer greater than or equal to 1, and the capacity of the target capacitor is equal to a preset threshold; The first end of the resonant capacitor is connected to the second end of the first transformer, and the second end of the resonant capacitor is connected to the first end of the second transformer.

3. The dual transformer series alternating inverter circuit as claimed in claim 2, characterized in that: The H-bridge circuit includes a first switch tube, a second switch tube, a third switch tube, and a fourth switch tube; The source of the first switch tube is connected to the drain of the third switch tube, and the first output end is provided on the formed connection line; the source of the second switch tube is connected to the drain of the fourth switch tube, and the second output end is provided on the formed connection line; The drain of the first switch tube is connected to the drain of the second switch tube, and the positive electrode connection point is provided on the formed connection line; the source of the third switch tube is connected to the source of the fourth switch tube, and the negative electrode connection point is provided on the formed connection line; and The gate electrodes corresponding to the first switch tube, the second switch tube, the third switch tube and the fourth switch tube are respectively connected to the sampling controller.

4. The dual transformer series alternating inverter circuit as claimed in claim 3, characterized in that: The load circuit includes a fifth switch tube, a sixth switch tube, a seventh switch tube, an eighth switch tube, a first capacitor and a second capacitor; The source of the fifth switch tube is connected to the source of the sixth switch tube; the source of the seventh switch tube is connected to the source of the eighth switch tube; the drain of the sixth switch tube is connected to the first end of the first capacitor, and the first output electrode is provided on the formed connection line; the second end of the first capacitor is connected to the first end of the second capacitor; the drain of the eighth switch tube is connected to the second end of the second capacitor, and the second output electrode is provided on the formed connection line; the gate electrodes corresponding to the fifth switch tube, the sixth switch tube, the seventh switch tube and the eighth switch tube are respectively connected to the sampling control circuit; The drain of the fifth switching tube is connected to the third end of the first transformer, the drain of the seventh switching tube is connected to the third end of the second transformer, the fourth end of the first transformer is connected to the fourth end of the second transformer, and the connection point formed is connected to the connection line between the second end of the first capacitor and the first end of the second capacitor by the load circuit; or, the drain of the fifth switching tube is connected to the fourth end of the first transformer, the drain of the seventh switching tube is connected to the fourth end of the second transformer, the third end of the first transformer is connected to the third end of the second transformer, and the connection point formed is connected to the connection line between the second end of the first capacitor and the first end of the second capacitor by the load circuit.

5. The dual transformer series alternating inverter circuit as claimed in claim 4, characterized in that: The second output end of the H-bridge circuit is provided with a first current sensor; when the third end of the first transformer is connected to the third end of the second transformer, or the fourth end of the first transformer is connected to the fourth end of the second transformer, a second current sensor is provided on the connection point formed and the connection line of the load circuit; the ground end of the H-bridge circuit is provided with a third current sensor; the first current sensor, the second current sensor, and the third current sensor are respectively connected to the sampling control circuit; Among them, the first current sensor is used to sample the oscillation current amplitude signal, the second current sensor is used to sample the current amplitude signals of the fifth switch tube, the sixth switch tube, the seventh switch tube and the eighth switch tube respectively, and the third current sensor is used to sample the total current amplitude signal when the first switch tube, the second switch tube, the third switch tube and the fourth switch tube are working.

6. The dual transformer series alternating inverter circuit as claimed in claim 5, characterized in that: The preset points sampled by the sampling control circuit include: the first current sensor, the second current sensor, the third current sensor, the third end and the fourth end of the first transformer, the third end of the second transformer, the first end of the first capacitor, and the first end and the second end of the second capacitor; The sampling control circuit outputs a pulse width signal modulated by a waveform function to control the operation of the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube according to the current or voltage signal at the preset point and the power output requirements of the first output electrode and the second output electrode, and the power pulse width output by the forward transformer is used as a synchronization signal to control the operation of the fifth switch tube, the sixth switch tube, the seventh switch tube, and the eighth switch tube.

7. The dual transformer series alternating inverter circuit according to any one of claims 4 to 6, characterized in that: The sampling control circuit is used for: According to the current amplitude signals of the first switch tube, the second switch tube, the third switch tube, the fourth switch tube, the fifth switch tube, the sixth switch tube, the seventh switch tube and the eighth switch tube, the current amplitude signal of the main oscillation circuit, the voltage amplitude signals sampled at each point in the load circuit, and the transmission power requirement for generating a specified waveform function, a pulse signal is generated by changing the modulation pulse width, the modulation period and the phase shift timing, and the pulse signal is output to the gates of the first switch tube, the second switch tube, the third switch tube and the fourth switch tube respectively, so that the H-bridge circuit is configured to generate a predetermined waveform function according to the predetermined waveform function. Assume that the working mode works in a cycle; and according to the pulse power timing output to the first transformer and the second transformer, the gates of the fifth switch tube, the sixth switch tube, the seventh switch tube and the eighth switch tube are synchronously controlled to make the dual transformer series alternating inverter circuit work in a cycle, and the first transformer and the second transformer work alternately in forward and flyback conditions, to ensure that the first switch tube, the second switch tube, the third switch tube, the fourth switch tube, the fifth switch tube, the sixth switch tube, the seventh switch tube and the eighth switch tube all enter the conduction state when their respective body diodes are forward-conducted.

8. The dual transformer series alternating inverter circuit as claimed in claim 7, characterized in that: The preset working modes include working mode 1, working mode 2, working mode 3, working mode 4, working mode 5, working mode 6, working mode 7 and working mode 8; The first working mode is: the first switch tube and the fourth switch tube are in the on state, and the second switch tube and the third switch tube are in the off state; In the working mode 1, if the fifth switch tube and the sixth switch tube are in the off state, the first transformer is in the flyback state, and the seventh switch tube and the eighth switch tube are in the on state, then the second transformer is in the forward state, and power is output to the load circuit through the second transformer; if the fifth switch tube and the sixth switch tube are in the on state, the first transformer is in the forward state, power is output to the load circuit through the first transformer, and the seventh switch tube and the eighth switch tube are in the off state, and the second transformer is in the flyback state; Wherein, when the fifth switch tube and the sixth switch tube are in the on state, the first output electrode is a positive voltage; when the seventh switch tube and the eighth switch tube are in the on state, the second output electrode is a positive voltage.

9. The dual transformer series alternating inverter circuit as claimed in claim 8, characterized in that: The second working mode is: the first switch tube changes from the on state to the off state, the fourth switch tube remains in the on state, and the second switch tube and the third switch tube remain in the off state; In the second working mode, the primary inductance freewheeling characteristics of the transformer in the first transformer and the second transformer that is in the flyback state in the first working mode cause the body diode of the third switch tube to pass current and be turned on. The third switch tube is turned on when the voltage drop between the drain and the source is equal to the forward voltage drop of the body diode of the third switch tube. At this time, the third switch tube changes from the off state to the on state, reducing the freewheeling loss of the body diode of the third switch tube, and entering the third working mode.

10. The dual transformer series alternating inverter circuit as claimed in claim 8, characterized in that: The working mode three is: the third switch tube and the fourth switch tube are in the on state, and the first switch tube and the second switch tube remain in the off state; In the working mode three, the resonant current of the main oscillation circuit forms a closed loop through the third switch tube and the fourth switch tube.

11. The dual transformer series alternating inverter circuit according to claim 8, characterized in that: The fourth working mode is: the fourth switch tube changes from the on state to the off state, the third switch tube remains in the on state, and the first switch tube and the second switch tube remain in the off state; In the working mode four, the freewheeling characteristics of the primary inductances of the first transformer and the second transformer cause the body diode of the second switch tube to conduct and conduct freewheeling. The second switch tube is conducted when the voltage drop between the drain and the source is equal to the forward voltage drop of the body diode of the second switch tube. At this time, the second switch tube changes from a closed state to a conducting state, reducing the freewheeling loss of the body diode of the second switch tube, and enters the working mode five.

12. The dual transformer series alternating inverter circuit as claimed in claim 8, characterized in that: The working mode five is: the second switch tube and the third switch tube are in the on state, and the first switch tube and the fourth switch tube remain in the off state; In the working mode 5, if the fifth switch tube and the sixth switch tube are in the off state, the first transformer is in the flyback state, and the seventh switch tube and the eighth switch tube are in the on state, the second transformer is in the forward state, and power is output to the load circuit through the second transformer; if the fifth switch tube and the sixth switch tube are in the on state, the first transformer is in the forward state, power is output to the load circuit through the first transformer, and the seventh switch tube and the eighth switch tube are in the off state, and the second transformer is in the flyback state; Wherein, when the fifth switch tube and the sixth switch tube are in the on state, the first output electrode is a negative voltage, and when the seventh switch tube and the eighth switch tube are in the on state, the second output electrode is a negative voltage.

13. The dual transformer series alternating inverter circuit as claimed in claim 8, characterized in that: The sixth working mode is: the third switch tube changes from the on state to the off state, the second switch tube remains in the off state, and the first switch tube and the fourth switch tube remain in the off state; In the working mode six, the freewheeling characteristics of the primary inductance of the transformer in the first transformer and the second transformer that is in the flyback state in the previous working mode causes the body diode of the first switch tube to conduct and conduct, and the first switch tube is conducted when the voltage between the drain and the source is equal to the forward voltage of the body diode of the first switch tube, thereby reducing the freewheeling loss of the body diode of the first switch tube and entering the working mode seven.

14. The dual transformer series alternating inverter circuit as claimed in claim 8, characterized in that: The seventh working mode is: the first switch tube and the second switch tube are in the on state, and the third switch tube and the fourth switch tube remain in the off state; In the seventh working mode, the resonant current of the main oscillation circuit forms a closed loop through the first switch tube and the second switch tube.

15. The dual transformer series alternating inverter circuit as claimed in claim 8, characterized in that: The working mode eight is: the second switch tube changes from the on state to the off state, the first switch tube remains in the on state, and the third switch tube and the fourth switch tube remain in the off state; In the working mode eight, the freewheeling characteristics of the primary inductance in the first transformer and the second transformer cause the body diode of the fourth switch tube to conduct and freewheel, wherein when the drain and the source of the fourth switch tube are in a zero voltage state, the body diode of the fourth switch tube is forwardly conducted, reducing the freewheeling loss of the body diode of the fourth switch tube, and entering the working mode one.

16. The dual transformer series alternating inverter circuit as claimed in claim 4, characterized in that: The sampling control circuit is further used to: adjust the conduction timing of the fifth switch tube, the sixth switch tube, the seventh switch tube and the eighth switch tube, so that the first transformer and the second transformer are in the flyback and forward states and operate alternately, and cooperate with the first switch tube, the second switch tube, the third switch tube and the fourth switch tube to make the main oscillation circuit in a full resonance state when working; Among them, when the first transformer is in a forward state, the second transformer is in a flyback state; when the first transformer is in a flyback state, the second transformer is in a forward state; the full resonance state is realized by the primary inductance of the transformer in the flyback state of the first transformer or the second transformer and the resonant capacitor, and the transformer in the forward state of the first transformer or the second transformer is used to transfer power.

17. The dual transformer series alternating inverter circuit as claimed in claim 4, characterized in that: The sampling control circuit is also used to: control the on and off of the fifth switch tube, the sixth switch tube, the seventh switch tube and the eighth switch tube, so that the first transformer and the second transformer work alternately in the forward state and the flyback state; Wherein, when the fifth switch tube and the sixth switch tube are turned on, and the seventh switch tube and the eighth switch tube are turned off, the first transformer is in the forward state to provide power, and the second transformer is in the flyback state, the magnetic core is energized and participates in resonance; when the fifth switch tube and the sixth switch tube are turned off, and the seventh switch tube and the eighth switch tube are turned on, the second transformer is in the forward state to provide power, and the first transformer is in the flyback state, the magnetic core is energized and participates in oscillation; When any one of the first transformer and the second transformer is in a flyback state, resonance occurs between the primary inductance of the transformer and the resonant capacitor.

18. The dual transformer series alternating inverter circuit according to any one of claims 4 to 6 and 8 to 17, characterized in that: When the primary inductance of the transformer in the flyback state in the first transformer and the second transformer oscillates with the resonant capacitor, the sampling control circuit controls the conduction pulse width, PWM cycle, dead time and phase timing of the gates of the first switch tube, the second switch tube, the third switch tube and the fourth switch tube, so that the first switch tube, the second switch tube, the third switch tube and the fourth switch tube are all in the conduction state when their respective body diodes are turned on, and the main oscillation circuit is in a fully resonant state.

19. The dual transformer series alternating inverter circuit according to claim 17, characterized in that: When the fifth switch tube and the sixth switch tube are in the on state, and the seventh switch tube and the eighth switch tube are in the off state, the first transformer is in the forward state, and the output power current charges the first capacitor through the fifth switch tube and the sixth switch tube; when the fifth switch tube and the sixth switch tube are in the off state, and the seventh switch tube and the eighth switch tube are in the on state, the second transformer is in the forward state, and the output power current charges the second capacitor through the seventh switch tube and the eighth switch tube; Among them, the switching timing of the fifth switch tube, the sixth switch tube, the seventh switch tube and the eighth switch tube is consistent with the output pulse of the forward transformer; when the conduction period of the fifth switch tube and the sixth switch tube is consistent with the conduction period of the first switch tube and the fourth switch tube, the voltage of the first output electrode is greater than the voltage of the second output electrode, so that the output voltage and current waveform of the load circuit are in the positive half cycle of the alternating current; when the conduction period of the fifth switch tube and the sixth switch tube is consistent with the conduction period of the second switch tube and the third switch tube, the voltage of the second output electrode is greater than the voltage of the first output electrode, so that the output voltage and current waveform of the load circuit are in the negative half cycle of the alternating current.

20. The dual transformer series alternating inverter circuit as claimed in claim 19, characterized in that: When each of the fifth switch tube, the sixth switch tube, the seventh switch tube and the eighth switch tube is turned on, the tube voltage drop of the switch tube is clamped by the body diode of the switch tube, so that the body diode of the switch tube is in a forward conduction state each time the switch tube is turned on, thereby making the switch tube turned on with a minimum surge current value under the control of the sampling control circuit.

21. The dual transformer series alternating inverter circuit according to claim 7, characterized in that: Oscillation energy is stored in the transformer in the flyback state of the first transformer and the second transformer, and the oscillation energy is transmitted to the load circuit in the next alternating cycle, thereby minimizing the oscillation loss of the first transformer and the second transformer, and all power devices operate in the optimal ultra-low loss working condition, so that the dual-transformer series alternating inverter circuit can achieve extremely high transmission efficiency and a transmission power that is more than 1.5 times that of a single transformer forward state.

22. The dual transformer series alternating inverter circuit according to claim 7, characterized in that: The first transformer or the second transformer operates in a forward state or a flyback state, and when the voltage of the first output electrode is greater than the voltage of the second output electrode, the sine wave output by the load circuit is in a positive half cycle, or when the voltage of the first output electrode is less than the voltage of the second output electrode, the sine wave output by the load circuit is in a negative half cycle, all of which are completed by the fifth switch tube, the sixth switch tube, the seventh switch tube and the eighth switch tube in coordination with the timing of the first switch tube, the second switch tube, the third switch tube and the fourth switch tube; Among them, the fifth switch tube and the sixth switch tube are turned on in stages with the seventh switch tube and the eighth switch tube to realize bidirectional synchronous rectification output characteristics, so that the output power of the first output electrode and the second output electrode presents the fluctuation characteristics of at least one function waveform among a sine function waveform, an exponential function waveform, a square wave function waveform, and a trigonometric function waveform according to the characteristics of pulse width modulation.

23. The dual transformer series alternating inverter circuit according to claim 4, characterized in that: When the potential of the first output electrode is higher than the potential of the second output electrode and the output AC voltage is in the positive half cycle, the conduction timing of the fifth switch tube and the sixth switch tube when they are turned on is: the fifth switch tube is turned on first, and after the body diode of the sixth switch tube is turned on, the sixth switch tube is changed from the off state to the on state, so that the sixth switch tube works in a state where the body diode between the drain and the source is forwardly conducted and then turned on, and the first capacitor does not have current backflow, and the fifth switch tube that is turned on first works in a zero voltage and zero current state to conduct When the potential of the first output electrode is lower than that of the second output electrode and the output AC voltage is in the negative half cycle, the conduction timing of the fifth switch tube and the sixth switch tube when they are turned on is: the sixth switch tube is turned on first, and after the body diode of the fifth switch tube is turned on, the fifth switch tube is changed from the off state to the on state, so that the fifth switch tube works in a state of conduction when the body diode positive voltage is between the drain and the source, and the first capacitor will not have current backflow, and the sixth switch tube that is turned on first is turned on in the zero voltage and zero current state.

24. The dual transformer series alternating inverter circuit according to claim 4, characterized in that: When the seventh switch tube and the eighth switch tube are turned on, when the first output electrode potential is higher than the second output electrode potential and the output AC voltage is in the positive half cycle, the turn-on timing of the seventh switch tube and the eighth switch tube is: the eighth switch tube is turned on first, and after the body diode of the seventh switch tube is turned on, the seventh switch tube is changed from the off state to the on state, so that the seventh switch tube enters the on state when the body diode forward voltage is between the drain and the source, and the second capacitor does not have current backflow, and the eighth switch tube that is turned on first operates at zero voltage. When the first output electrode potential is lower than the second output electrode potential and the output AC voltage is in the negative half cycle, the conduction timing of the seventh switch tube and the eighth switch tube is as follows: the seventh switch tube is turned on first, and after the body diode of the eighth switch tube is turned on, the eighth switch tube is changed from the off state to the on state, so that the eighth switch tube enters the on state when the body diode forward voltage is between the drain and the source, and the second capacitor will not have current backflow, and the seventh switch tube that is turned on first enters the on state in the zero voltage and zero current state.

25. The dual transformer series alternating inverter circuit according to claim 4, characterized in that: The first switch tube, the second switch tube, the third switch tube, the fourth switch tube, the fifth switch tube, the sixth switch tube, the seventh switch tube and the eighth switch tube are all MOS switch tubes with body diodes; when the MOS switch tube is replaced with an IGBT switch tube with a body diode, the collector of the IGBT switch tube corresponds to the drain of the MOS switch tube, and the emitter of the IGBT switch tube corresponds to the source of the MOS switch tube.

26. An inverter device, characterized in that: It includes the dual-transformer series alternating inverter circuit as described in any one of claims 1-25.

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