Control method of micro inverter and related equipment

Abstract

The invention relates to a micro inverter control method and related equipment, and relates to the technical field of micro inverters. A specific embodiment of the method comprises the steps of obtaining an output voltage value corresponding to an output end of a voltage doubling rectifying circuit, and determining a target adjustment strategy according to the output voltage value; according to the target adjustment strategy, adjusting a plurality of switch tubes in the micro inverter to control the output gain of the micro inverter; wherein the micro inverter is used for transmitting sine wave alternating current to an alternating current power grid based on a circuit topology of primary power conversion, the circuit topology of the micro inverter comprises a resonance circuit, a winding transformer and a voltage doubling rectifying circuit, the resonance circuit is connected with a primary winding of the winding transformer, and the voltage doubling rectifying circuit is connected with a secondary winding of the winding transformer. According to the implementation mode, the output gain control of the micro inverter based on the primary power conversion topology is realized, the efficiency and the power of the micro inverter are improved, and the cost of the micro inverter is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of micro inverters, and in particular to a control method of a micro inverter and related equipment. Background Art

[0002] Micro inverters generally refer to inverters with a power of less than or equal to 1000 watts and component-level MPPT (Maximum Power Point Tracking) in photovoltaic power generation systems. The full name is micro photovoltaic grid-connected inverters. "Micro inverters" are relative to traditional centralized inverters. The traditional photovoltaic inverter method is to connect all the DC power generated by photovoltaic cells under sunlight in series and parallel, and then use an inverter to invert the DC power into AC power and connect it to the grid; micro inverters invert each component. Its advantage is that each component can be independently controlled by MPPT, which can greatly improve the overall efficiency.

[0003] Micro inverters help reduce damage to the panels of photovoltaic modules and reduce the impact of inverter failures on photovoltaic grid-connected power generation systems. Compared with centralized inverters, they have high reliability and low power generation costs, and have better application scenarios. However, the current circuit topology of micro inverters is mainly based on flyback circuit topology, which is limited by the volume of transformer core and switching frequency, and has low power and efficiency. In order to meet the needs of high-power photovoltaic modules, the relevant technology mainly adopts a two-stage power conversion topology to improve the power and efficiency of micro inverters, and adjusts the output gain based on the two-stage power conversion topology. At present, there is no one-stage power conversion micro inverter that meets the needs of high-power photovoltaic modules, and there is no solution for how to control the output gain of a one-stage power conversion micro inverter. Summary of the invention

[0004] A control method and related equipment for a micro inverter provided by an embodiment of the present invention at least solve the problem in the related art that there is no micro inverter based on primary power conversion for output gain control.

[0005] In order to solve the above problems, one aspect of an embodiment of the present invention provides a control method for a micro inverter, wherein the micro inverter is used to transmit sinusoidal AC power to an AC power grid based on a circuit topology of primary power conversion, and the circuit topology of the micro inverter includes: a resonant circuit, a winding transformer, and a voltage doubler rectifier circuit, wherein the resonant circuit is connected to a primary winding of the winding transformer, and the voltage doubler rectifier circuit is connected to a secondary winding of the winding transformer; the method includes:

[0006] Obtaining an output voltage value corresponding to an output terminal of the voltage doubler rectifier circuit, and determining a target regulation strategy according to the output voltage value;

[0007] According to the target regulation strategy, multiple switch tubes in the micro inverter are regulated to control the output gain of the micro inverter.

[0008] In some of the embodiments, the step of obtaining an output voltage value corresponding to an output terminal of the voltage doubler rectifier circuit and determining a target regulation strategy according to the output voltage value includes:

[0009] Obtaining an output voltage value of an output terminal of the voltage doubler rectifier circuit, and determining whether the output voltage value is greater than or equal to a preset voltage value;

[0010] If the output voltage value is greater than or equal to the preset voltage value, the target adjustment strategy is determined to be to adjust the switching frequency corresponding to the multiple switching tubes in the micro-inverter; if the output voltage value is less than the preset voltage value, the target adjustment strategy is determined to be to adjust the phase shift angle corresponding to the multiple switching tubes in the micro-inverter.

[0011] In some embodiments, if the target adjustment strategy is to adjust the switching frequencies corresponding to the multiple switch tubes in the micro inverter, the step of adjusting the multiple switch tubes in the micro inverter to control the output gain of the micro inverter according to the target adjustment strategy includes:

[0012] Obtain the maximum power value of the photovoltaic module and the grid voltage value in the AC power grid, and determine the output current given value corresponding to the output end of the voltage doubler rectifier circuit according to the maximum power value and the grid voltage value;

[0013] The induced current value in the voltage doubler rectifier circuit is obtained, the difference between the absolute value of the output current given value and the absolute value of the induced current value is compared, and the switching frequencies of multiple switching tubes are determined according to the difference to achieve the output gain control of the micro inverter.

[0014] In some embodiments, if the target adjustment strategy is the phase shift angle corresponding to multiple switch tubes in the micro inverter, then according to the target adjustment strategy, the step of adjusting the multiple switch tubes in the micro inverter to control the output gain of the micro inverter includes:

[0015] Determine the sine wave period corresponding to the output current at the output end of the voltage doubler rectifier circuit, and obtain the switching frequency of multiple switch tubes in the micro inverter within the sine wave period;

[0016] Obtain the mapping relationship between the output voltage gain and the phase shift angle, and adjust the phase shift angle between the switch tube in the first bridge arm and the switch tube in the second bridge arm in the resonant circuit according to the mapping relationship, the sine wave period and the switching frequency, so as to adjust the duty cycle of multiple switch tubes in the voltage doubler rectifier circuit and realize the control of the output gain of the micro inverter.

[0017] In some of the embodiments, during the process of adjusting the phase shift angle between the switch tube in the first bridge arm and the switch tube in the second bridge arm in the resonant circuit, the method further includes: maintaining a constant switching frequency of the plurality of switch tubes in the micro inverter.

[0018] In some of the embodiments, the method further comprises the step of determining a sinusoidal wave period corresponding to an output current at an output end of the voltage doubler rectifier circuit:

[0019] Obtaining a grid voltage value in the AC grid, and determining a current value of an output current according to the grid voltage value and a maximum power value of a photovoltaic module;

[0020] If the current value is greater than 0, it is determined that the sine wave corresponding to the output current is in the positive half cycle of the sine wave; if the current value is less than 0, it is determined that the sine wave corresponding to the output current is in the negative half cycle of the sine wave; wherein the sine wave frequency of the output current is consistent with the sine wave frequency of the alternating current in the alternating current power grid.

[0021] In some of these embodiments, the method further comprises:

[0022] The output current phase corresponding to the output end of the voltage doubler rectifier circuit is adjusted so that the phase difference between the output current phase and the grid AC phase is greater than 0, so as to achieve reactive power regulation of the micro inverter.

[0023] In some of the embodiments, the working state of the multiple switch tubes is a soft switching state.

[0024] In order to solve the above problems, one aspect of an embodiment of the present invention provides a micro inverter, including: a processor, and a memory for storing a program, characterized in that the program includes instructions, and when the instructions are executed by the processor, the processor executes a control method according to any of the above micro inverters.

[0025] In order to solve the above problems, one aspect of an embodiment of the present invention provides a non-transitory machine-readable medium storing computer instructions, wherein the computer instructions are used to enable a computer to execute any of the above-mentioned micro-inverter control methods.

[0026] Beneficial effects of the embodiments of the present invention: A micro-inverter that transmits sinusoidal AC power to an AC power grid based on a circuit topology of a first-stage power conversion, obtains an output voltage value corresponding to the output end of a voltage-doubling rectifier circuit, and determines a target adjustment strategy based on the output voltage value; according to the target adjustment strategy, multiple switch tubes in the micro-inverter are adjusted to control the output gain of the micro-inverter; wherein the circuit topology of the micro-inverter includes: a resonant circuit, a winding transformer and a voltage-doubling rectifier circuit, the resonant circuit is connected to the primary winding of the winding transformer, and the voltage-doubling rectifier circuit is connected to the secondary winding of the winding transformer. The problem of low efficiency and power, complex control process and high cost of the micro-inverter caused by the use of a circuit topology of two-stage power conversion and the corresponding output gain control in the related art is overcome; the output gain control of the micro-inverter based on the first-stage power conversion topology is realized, the efficiency and power of the micro-inverter are improved, the control process of the micro-inverter is simplified, and the cost of the micro-inverter is reduced.

[0027] The details of one or more embodiments of the invention are set forth in the following drawings and description so that other features, objects, and advantages of the invention are more readily apparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other embodiments can be obtained based on these drawings without creative work.

[0029] Figure 1 It is a flowchart of a control method of a micro inverter according to an embodiment of the present invention.

[0030] Figure 2 It is a flowchart of a control method of a micro inverter according to another embodiment of the present invention.

[0031] Figure 3 It is a schematic diagram of the electrical topology of a micro inverter of a primary power conversion topology according to an embodiment of the present invention.

[0032] Figure 4 Schematic diagram of the structure of the electronic device of this embodiment. DETAILED DESCRIPTION

[0033] Embodiments of the present embodiment will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present embodiment are shown in the accompanying drawings, it should be understood that the present embodiment can be implemented in various forms and should not be construed as being limited to the embodiments set forth herein, which are instead provided for a more thorough and complete understanding of the present embodiment. It should be understood that the drawings and embodiments of the present embodiment are only for exemplary purposes and are not intended to limit the scope of protection of the present embodiment.

[0034] The current circuit topology of micro inverters is mainly based on the flyback circuit topology. The secondary side of the transformer converts the output current into AC through a folding circuit. This circuit topology is limited by the volume of the transformer core and the switching frequency. It is difficult to increase the power, and the efficiency of the inverter is low. As the power of photovoltaic modules increases, the power and efficiency of micro inverters are required to increase. Most micro inverters in related technologies use two-stage power conversion technology, but the total efficiency of the micro inverter during two-stage power conversion is equal to the product of the two conversion efficiencies, which makes it difficult for the efficiency of the micro inverter to exceed 96%. That is, although the power and efficiency of the micro inverter are improved by adopting a two-stage power conversion topology in related technologies, and the output gain is adjusted based on the two-stage power conversion topology, it is still difficult to meet the needs of high-power photovoltaic modules, and the control process of the micro inverter is complex and the cost is high.

[0035] In order to solve the above problems, an embodiment of the present invention provides a control method for a micro inverter, and the control method for the micro inverter is applied to a micro inverter based on a primary power conversion topology, such as Figure 1 As shown, the control method of the micro inverter includes:

[0036] Step S101, obtaining an output voltage value corresponding to an output terminal of a voltage doubler rectifier circuit, and determining a target regulation strategy according to the output voltage value.

[0037] Among them, the micro-inverter provided by the embodiment of the present invention is used to transmit sinusoidal AC power to the AC power grid based on the circuit topology of the primary power conversion. The circuit topology of the micro-inverter includes: a resonant circuit, a winding transformer and a voltage doubler rectifier circuit. The resonant circuit is connected to the primary winding of the winding transformer, and the voltage doubler rectifier circuit is connected to the secondary winding of the winding transformer. Through the above settings, the embodiment of the present invention obtains the output voltage value corresponding to the output end of the voltage doubler rectifier circuit, and adjusts the output gain of the micro-inverter according to the target adjustment strategy based on the output voltage value, thereby improving the output gain adjustment effect and helping to improve the power and efficiency of the micro-inverter with the primary power conversion topology.

[0038] In some of the embodiments, the target adjustment strategy includes two strategies: a switching frequency adjustment strategy and a phase shift angle adjustment strategy. The switching frequency adjustment strategy is: output gain control is performed by adjusting the switching frequencies corresponding to the multiple switch tubes in the micro-inverter; the phase shift angle adjustment strategy is: output gain control is performed by adjusting the phase shift angles corresponding to the multiple switch tubes in the micro-inverter. The above-mentioned steps of obtaining the output voltage value corresponding to the output end of the voltage doubler rectifier circuit and determining the target adjustment strategy according to the output voltage value include: obtaining the output voltage value of the output end of the voltage doubler rectifier circuit, and determining whether the output voltage value is greater than or equal to the preset voltage value; if the output voltage value is greater than or equal to the preset voltage value, then determining that the target adjustment strategy is the switching frequency adjustment strategy; if the output voltage value is less than the preset voltage value, then determining that the target adjustment strategy is the phase shift angle adjustment strategy.

[0039] Among them, since the output current is a sinusoidal alternating current, the output voltage value also fluctuates around the voltage zero point. Therefore, in the step of determining whether the output voltage value is greater than or equal to the preset voltage value, the embodiment of the present invention compares the obtained absolute value of the output voltage value with the preset voltage value, and the value of the preset voltage value is a positive number.

[0040] Step S102: According to the target adjustment strategy, multiple switch tubes in the micro inverter are adjusted to control the output gain of the micro inverter.

[0041] Based on the above target adjustment strategy, multiple switch tubes in the micro inverter are adjusted to achieve output gain control, which reduces the complexity of the output gain control process and helps to reduce the cost of the micro inverter.

[0042] The above steps specifically disclose the specific steps of determining the target adjustment strategy according to the output voltage value. When the output voltage value is large, that is, the output voltage value is greater than or equal to the preset voltage value, the switching frequency of the switch tube is negatively correlated with the output gain. Increasing the switching frequency can reduce the output gain. Therefore, the target adjustment strategy is determined to be the switching frequency adjustment strategy, that is, the output gain control is performed by adjusting the switching frequencies corresponding to multiple switch tubes in the micro-inverter. When the output voltage value is small, that is, the output voltage value is less than the preset voltage value, since the switching frequency has been adjusted to the maximum, the output gain can no longer be reduced by increasing the switching frequency. At this time, the target adjustment strategy can be determined to be the phase shift angle adjustment strategy, that is, the output gain control is performed by adjusting the phase shift angles corresponding to multiple switch tubes in the micro-inverter. The embodiment of the present invention thus realizes output gain control over a wide voltage range for a micro-inverter with a primary power conversion topology, and expands the applicable scenarios of micro-inverters with a primary power conversion topology.

[0043] In some of the embodiments, if the target adjustment strategy is a switching frequency adjustment strategy; then the step of adjusting the switching frequencies corresponding to multiple switching tubes in the micro-inverter according to the target adjustment strategy to control the output gain of the micro-inverter includes: obtaining the maximum power value of the photovoltaic component and the grid voltage value in the AC power grid, and determining the output current set value corresponding to the output end of the voltage doubler rectifier circuit according to the maximum power value and the grid voltage value; obtaining the induced current value in the voltage doubler rectifier circuit, comparing the difference between the absolute value of the output current set value and the absolute value of the induced current value, and determining the switching frequencies of the multiple switching tubes according to the difference to achieve control of the output gain of the micro-inverter.

[0044] The above steps provide a specific operation implementation method for adjusting the output gain of the micro-inverter by adjusting the switching frequencies corresponding to the multiple switch tubes in the micro-inverter. The embodiment of the present invention is based on the output gain control of the micro-inverter of the primary power conversion topology, and the output end of the micro-inverter provides sinusoidal AC power to the AC power grid. According to an embodiment of the present invention, an MTTP (Maximum Power Point Tracking) controller can be used to detect the maximum power value of a photovoltaic module, and then when the photovoltaic module meets the maximum power value, the current input by the photovoltaic module is received, and then the output current given value is determined in combination with the grid voltage value in the AC grid, and the output current given value is processed by taking the absolute value as the target given signal of the drive controller, and the induced current value in the secondary winding of the voltage doubler rectifier circuit is obtained, and the absolute value and filtering are also performed as the feedback signal of the output current sampling, and the feedback signal of the output current sampling is compared with the target given signal of the drive controller to determine the signal difference, and the signal difference is PI-regulated by a PI (proportional integral controller) regulator to form a current loop control signal, and then the current loop control signal is processed by a voltage-frequency converter to output a frequency-adjustable drive signal to adjust the switching frequency of multiple switch tubes in the micro inverter, so as to control the output gain of the micro inverter and improve the power and efficiency of the micro inverter. Wherein, after the above difference is adjusted by the PI regulator, the switching frequency corresponding to the switch tube is finally output. When the target given signal corresponding to the output current given value is greater than the feedback signal corresponding to the induced current value, that is, the signal difference is positive, the output switching frequency decreases; when the target given signal corresponding to the output current given value is less than the feedback signal corresponding to the induced current value, that is, the signal difference is negative, the output switching frequency increases.

[0045] In some of the embodiments, if the target adjustment strategy is a phase shift angle adjustment strategy; then the step of adjusting the phase shift angles corresponding to multiple switch tubes in the micro-inverter according to the target adjustment strategy to control the output gain of the micro-inverter includes: determining the sinusoidal wave period corresponding to the output current at the output end of the voltage doubler rectifier circuit, and obtaining the switching frequency of the multiple switch tubes in the micro-inverter within the sinusoidal wave period; obtaining the mapping relationship between the output voltage gain and the phase shift angle, and adjusting the phase shift angle between the switch tube in the first bridge arm and the switch tube in the second bridge arm in the resonant circuit according to the mapping relationship, the sinusoidal wave period and the switching frequency, so as to adjust the duty cycle of the multiple switch tubes in the voltage doubler rectifier circuit and realize the control of the output gain of the micro-inverter.

[0046] The above steps provide a specific operation implementation method for adjusting the output gain of the micro-inverter by adjusting the phase shift angle corresponding to multiple switch tubes in the micro-inverter. In combination with the sine wave period of the output current, the constant switching frequency, and the mapping relationship between the output voltage gain and the phase shift angle, the phase shift angle between the switch tubes in the first bridge arm and the second bridge arm in the resonant circuit corresponding to the primary side of the micro-inverter is adjusted, which effectively reduces the equivalent duty cycle of the switch tube in the voltage doubler rectifier circuit corresponding to the secondary side of the micro-inverter, and reduces the output gain. Among them, the mapping relationship between the output voltage gain and the phase shift angle provided by the embodiment of the present invention can be determined by a pre-set mapping relationship table. It is also possible to obtain the expected output gain and the actual output gain and determine the output gain difference between the two, and then sample the PI controller to output the gain difference for PI regulation. After the output gain difference is adjusted by the PI regulator, the corresponding phase shift angle value is output; wherein, when the expected output gain is greater than the actual output gain, that is, the output gain difference is positive, the output phase shift angle value decreases; when the expected output gain is less than the actual output gain, that is, the output gain difference is negative, the output phase shift angle value increases.

[0047] In some of the embodiments, in the process of adjusting the phase shift angle between the switch tube in the first bridge arm and the switch tube in the second bridge arm in the resonant circuit, the method further includes: keeping the switching frequency of multiple switch tubes in the micro inverter constant.

[0048] When the output voltage value is greater than or equal to the preset voltage value, the output gain can be reduced by increasing the switching frequency. However, when the output voltage value is less than the preset voltage value, the switching frequency is increased to the maximum range and the output gain can no longer be further controlled. Therefore, it is necessary to adjust the phase shift angle between the switch tube in the first bridge arm and the switch tube in the second bridge arm in the resonant circuit to further reduce the output gain. In this process, keeping the switching frequency of multiple switch tubes in the micro-inverter constant, that is, maintaining the switching frequency at the maximum switching frequency value, helps to cooperate with the phase shift angle to improve the output gain control effect, and can also simplify the complexity of the control process.

[0049] In some of the embodiments, the method further includes the step of determining the sinusoidal wave period corresponding to the output current at the output end of the voltage doubler rectifier circuit: obtaining the grid voltage value in the AC power grid, and determining the current value of the output current according to the grid voltage value and the maximum power value of the photovoltaic component; if the current value is greater than 0, determining that the sinusoidal wave corresponding to the output current is in the positive half-cycle of the sinusoidal wave; if the current value is less than 0, determining that the sinusoidal wave corresponding to the output current is in the negative half-cycle of the sinusoidal wave; wherein the phase and frequency of the sinusoidal wave of the output current are consistent with the frequency of the sinusoidal wave of the AC power in the AC power grid.

[0050] Through the above settings, combined with the current demand of the AC power grid and the maximum power value of the photovoltaic module, the sine wave period corresponding to the output current of the micro-inverter is determined, which is helpful for controlling the conduction and shutdown of multiple switching tubes in the micro-inverter based on the sine wave period. That is, by controlling the switching frequency of the switching tube, the current circuit flipping within the sine wave period is realized to output sinusoidal AC power that meets the needs of the AC power grid.

[0051] In some of the embodiments, the method further includes: adjusting the output current phase corresponding to the output end of the voltage doubler rectifier circuit so that the phase difference between the output current phase and the grid AC phase is greater than 0, so as to achieve reactive power regulation of the micro inverter.

[0052] When the phase difference between the output current and the grid AC is 0, all active power is output at this time. When the phase difference between the output current and the grid AC is 180°, all reactive power is output at this time. Therefore, through the above settings, the phase of the output current corresponding to the output end of the voltage doubler rectifier circuit can be adjusted so that the phase difference between the output current and the grid AC is greater than 0, thereby realizing the reactive power regulation function. At the same time, the output reactive power can be adjusted by adjusting the size of the phase difference to meet the different scene requirements of the micro inverter.

[0053] In some of the embodiments, the working state of the above-mentioned multiple switch tubes is a soft switching state.

[0054] In the micro-inverter with a one-stage power conversion topology provided in the embodiment of the present invention, multiple switch tubes can operate in a soft switching state, thereby reducing switching losses and thereby improving the power generation of the micro-inverter.

[0055] The control method of the micro-inverter provided in the embodiment of the present invention is a micro-inverter that transmits sinusoidal AC power to the AC power grid based on the circuit topology of the first-stage power conversion, by obtaining the output voltage value corresponding to the output end of the voltage doubler rectifier circuit, and determining the target adjustment strategy according to the output voltage value; according to the target adjustment strategy, multiple switch tubes in the micro-inverter are adjusted to control the output gain of the micro-inverter; wherein, the circuit topology of the micro-inverter includes: a resonant circuit, a winding transformer and a voltage doubler rectifier circuit, the resonant circuit is connected to the primary winding of the winding transformer, and the voltage doubler rectifier circuit is connected to the secondary winding of the winding transformer. The technical means overcomes the problems of low efficiency and power, complex control process and high cost of the micro-inverter caused by the circuit topology of two-stage power conversion and the corresponding output gain control in the related art; the output gain control of the micro-inverter based on the first-stage power conversion topology is realized, the efficiency and power of the micro-inverter are improved, the control process of the micro-inverter is simplified, and the cost of the micro-inverter is reduced.

[0056] In order to solve the above problem, another embodiment of the present invention provides a control method of a micro inverter, and the control method of the micro inverter is applied to a micro inverter based on a primary power conversion topology, such as Figure 2 As shown, the control method of the micro inverter includes:

[0057] Step S201, obtaining an output voltage value and a preset voltage value corresponding to an output end of a voltage doubler rectifier circuit.

[0058] The micro inverter provided in the embodiment of the present invention is used to transmit sinusoidal AC power to the AC power grid based on a circuit topology of primary power conversion. Figure 3 A schematic diagram of a circuit topology of a micro inverter in an embodiment of the present invention is shown. Figure 3 As shown, the circuit topology of the above-mentioned micro inverter includes: a resonant circuit, a winding transformer and a voltage doubler rectifier circuit, the resonant circuit is connected to the primary winding of the winding transformer, and the voltage doubler rectifier circuit is connected to the secondary winding of the winding transformer.

[0059] Specifically, the resonant circuit is connected to the primary winding of the winding transformer, and the input end of the resonant circuit is connected to the photovoltaic module for receiving the current input by the photovoltaic module; the voltage doubler rectifier circuit includes a switch bridge arm and a capacitor bridge arm connected in parallel, and the voltage doubler rectifier circuit is connected to the secondary winding of the winding transformer, and is used to generate an induced current through the secondary winding, and the induced current flows through the capacitor in the capacitor bridge arm to form an induced current loop and realize multiple voltage boost; wherein, the output end of the voltage doubler rectifier circuit is used to transmit a sinusoidal output current to the AC power grid.

[0060] In some of the embodiments, Figure 3As shown, when the resonant circuit is a full-bridge resonant circuit, it includes: a first bridge arm, a second bridge arm and an LLC circuit; wherein the first bridge arm and the second bridge arm are connected in parallel, the first bridge arm includes a first switch tube Q1 and a second switch tube Q2 connected in series, and the second bridge arm includes a third switch tube Q3 and a fourth switch tube Q4 connected in series; the LLC circuit includes a leakage inductance Lr, an excitation inductance Lm and a resonant capacitor Cr connected in series, wherein the excitation inductance Lm is also the primary winding of the winding transformer. One end of the LLC circuit is connected to the midpoint of the first bridge arm, and the other end of the LLC circuit is connected to the midpoint of the second bridge arm.

[0061] In some of the embodiments, Figure 3 As shown, the switch bridge arm in the voltage doubler rectifier circuit includes an upper switch bridge arm and a lower switch bridge arm, wherein the upper switch bridge arm includes a fifth switch tube Q5 and a sixth switch tube Q6 connected in series and arranged in a mirror image, and the lower switch bridge arm includes a seventh switch tube Q7 and an eighth switch tube Q8 connected in series and arranged in a mirror image. The capacitor bridge arm in the voltage doubler rectifier circuit includes a second capacitor C2 and a third capacitor C3 connected in series; wherein one end of the secondary winding is connected to the midpoint of the switch bridge arm, and the other end of the secondary winding is connected to the midpoint of the capacitor bridge arm. A filter inductor Lg is provided at the output end of the voltage doubler rectifier circuit. The filter inductor Lg can be provided on one side of the output end of the voltage doubler rectifier circuit, or on both sides of the output end of the voltage doubler rectifier circuit. At the same time, the filter inductor can also be provided at the output end of the voltage doubler rectifier circuit in the form of a common mode inductor. The embodiment of the present invention forms an LC high-frequency filter circuit by using the capacitor in the capacitor bridge arm provided in the voltage doubler rectifier circuit and the filter inductor provided at the output end of the voltage doubler rectifier circuit, thereby achieving a filtering processing effect on the output current.

[0062] The micro-inverter applied based on the embodiment of the present invention realizes that a circuit topology based on primary power conversion can transmit sinusoidal AC power to the AC power grid, thereby effectively improving the efficiency and power of the micro-inverter.

[0063] Step S202, determine whether the output voltage value is greater than or equal to the preset voltage value. If yes, that is, the output voltage value is greater than or equal to the preset voltage value, execute step S203; if no, that is, the output voltage value is less than the preset voltage value, go to step S204.

[0064] Among them, since the output current is a sinusoidal alternating current, the output voltage value also fluctuates around the voltage zero point. Therefore, when comparing the magnitude relationship between the output voltage value and the preset voltage value, the embodiment of the present invention compares the absolute value of the obtained output voltage value with the preset voltage value, and the numerical value of the preset voltage value is a positive number.

[0065] Through the above-mentioned settings, the embodiment of the present invention obtains the output voltage value corresponding to the output end of the voltage doubler rectifier circuit, so as to determine different output gain adjustment strategies as target adjustment strategies according to the size relationship between the output voltage value and the preset voltage value, which helps to improve the power and efficiency of the micro inverter with a first-stage power conversion topology and improves the output gain adjustment effect.

[0066] Step S203, determine that the target regulation strategy is a switching frequency regulation strategy; obtain the maximum power value of the photovoltaic component and the grid voltage value in the AC power grid, and determine the output current set value corresponding to the output end of the voltage doubler rectifier circuit according to the maximum power value and the grid voltage value; obtain the induced current value in the voltage doubler rectifier circuit, compare the difference between the absolute value of the output current set value and the absolute value of the induced current value, and determine the switching frequency of multiple switching tubes according to the difference to achieve control of the output gain of the micro inverter.

[0067] Among them, the switching frequency adjustment strategy provided by the embodiment of the present invention is: output gain control is performed by adjusting the switching frequencies corresponding to multiple switch tubes in the micro inverter. When the output voltage value is large, that is, the output voltage value is greater than or equal to the preset voltage value, the switching frequency of the switch tube is negatively correlated with the output gain. Increasing the switching frequency can reduce the output gain. Therefore, at this time, the target adjustment strategy is determined to be the switching frequency adjustment strategy, that is, by adjusting the switching frequencies corresponding to multiple switch tubes in the micro inverter.

[0068] The above steps provide a specific operation implementation method for adjusting the output gain of the micro-inverter by adjusting the switching frequencies corresponding to the multiple switch tubes in the micro-inverter. The embodiment of the present invention is based on the output gain control of the micro-inverter of the primary power conversion topology, and the output end of the micro-inverter provides sinusoidal AC power to the AC power grid. According to an embodiment of the present invention, an MTTP controller can be used to detect the maximum power value of a photovoltaic module, and then when the photovoltaic module meets the maximum power value, the current input by the photovoltaic module is received, and then the output current given value is determined in combination with the grid voltage value in the AC power grid, and the output current given value is processed by taking the absolute value as the target given signal of the drive controller, and at the same time, the induced current value in the secondary winding of the voltage doubler rectifier circuit is obtained, and the absolute value and filtering processing are also performed as the feedback signal of the output current sampling, and the feedback signal of the output current sampling is compared with the target given signal of the drive controller to determine the signal difference, and the signal difference is PI-regulated by a PI regulator to form a current loop control signal, and then the current loop control signal is processed by a voltage-frequency converter to output a frequency-adjustable drive signal to adjust the switching frequency of multiple switch tubes in the micro inverter, so as to control the output gain of the micro inverter and improve the power and efficiency of the micro inverter. Among them, after the above-mentioned difference is adjusted by the PI regulator, the switching frequency corresponding to the switching tube is finally output. Among them, when the target given signal corresponding to the output current given value is greater than the feedback signal corresponding to the induced current value, that is, the signal difference is positive, the output switching frequency decreases; when the target given signal corresponding to the output current given value is less than the feedback signal corresponding to the induced current value, that is, the signal difference is negative, the output switching frequency increases.

[0069] In some of the embodiments, if the sinusoidal wave period of the output current is the positive half period of the sinusoidal wave, then in the process of adjusting the switching frequency to control the output gain: when the first switch tube and the fourth switch tube in the resonant circuit are turned on, the current input by the photovoltaic component forms a first conduction current loop in the resonant circuit, and generates an induced current in the voltage doubler rectifier circuit, controls the fifth switch tube and the sixth switch tube to be turned on, and the induced current flows through the second capacitor in the capacitor bridge arm to form a first induced current loop; wherein, the current input by the photovoltaic component in the first conduction current loop passes through the MOS tube of the first switch tube, the LLC circuit, the MOS tube of the fourth switch tube, and the first capacitor in sequence; the induced current in the first induced current loop passes through the MOS tube of the sixth switch tube, the parasitic diode of the fifth switch tube, and the second capacitor in sequence. When the first switch tube and the fourth switch tube in the resonant circuit are turned off, and the third switch tube and the second switch tube are controlled to be turned on, the resonant cavity current in the resonant circuit feeds the first capacitor on the DC side bus to form a second conduction current loop, and forms an induced current in the voltage doubler rectifier circuit, and the seventh switch tube and the eighth switch tube are controlled to be turned on, and the induced current flows through the third capacitor in the capacitor bridge arm to form a second induced current loop; wherein, the resonant cavity current in the second conduction current loop passes through the parasitic diode of the third switch tube, the first capacitor, the parasitic diode of the second switch tube, and the LLC circuit in sequence; and the induced current in the second induced current loop passes through the third capacitor, the MOS tube of the eighth switch tube, and the parasitic diode of the seventh switch tube in sequence.

[0070] In some of the embodiments, when the resonant cavity current is zero, the photovoltaic component inputs current to the resonant circuit through the first capacitor on the DC side bus to form a third conduction current loop, and generates an induced current in the voltage doubler rectifier circuit, and the induced current flows through the third capacitor in the capacitor bridge arm to form a third induced current loop; wherein, the current input by the photovoltaic component in the third conduction current loop passes through the MOS tube of the third switch tube, the LLC circuit, the MOS tube of the second switch tube, and the first capacitor in sequence, and the induced current in the third induced current loop passes through the third capacitor, the MOS tube of the eighth switch tube, and the parasitic diode of the seventh switch tube in sequence. When the third switch tube and the second switch tube in the resonant circuit are turned off, the first switch tube and the fourth switch tube are controlled to be turned on, and the resonant cavity current in the resonant circuit feeds the first capacitor on the DC side bus to form a fourth conduction current loop, and generates an induced current in the voltage doubler rectifier circuit, and the fifth switch tube and the sixth switch tube are controlled to be turned on, and the induced current flows through the second capacitor in the capacitor bridge arm to form a fourth induced current loop; wherein, the current in the fourth conduction current loop passes through the parasitic diode of the fourth switch tube, the LLC circuit, the parasitic diode of the first switch tube, and the first capacitor in sequence, and the induced current in the fourth induced current loop passes through the MOS tube of the sixth switch tube, the parasitic diode of the fifth switch tube, and the second capacitor in sequence.

[0071] In some of the embodiments, if the sinusoidal wave period of the output current is the negative half period of the sinusoidal wave, then in the process of adjusting the switching frequency to control the output gain: when the first switch tube and the fourth switch tube in the resonant circuit are turned on, the current input by the photovoltaic component forms a fifth conduction current loop in the resonant circuit, and generates an induced current in the voltage doubler rectifier circuit, and controls the seventh switch tube and the eighth switch tube to be turned on, and the induced current flows through the third capacitor in the capacitor bridge arm to form a fifth induced current loop; wherein, the current input by the photovoltaic component in the fifth conduction current loop passes through the MOS tube of the first switch tube, the LLC circuit, the MOS tube of the fourth switch tube, and the first capacitor in sequence; the induced current in the fifth induced current loop passes through the MOS tube of the seventh switch tube, the parasitic diode of the eighth switch tube, and the third capacitor in sequence. When the first switch tube and the fourth switch tube in the resonant circuit are turned off, and the third switch tube and the second switch tube are turned on, the resonant cavity current in the resonant circuit feeds the first capacitor on the DC side bus to form a sixth conduction current loop, and forms an induced current in the voltage doubler rectifier circuit, controls the fifth switch tube and the sixth switch tube to be turned on, and the induced current flows through the second capacitor in the capacitor bridge arm to form a sixth induced current loop; wherein, the resonant cavity current in the sixth conduction current loop passes through the parasitic diode of the second switch tube, the LLC circuit, the parasitic diode of the third switch tube, and the first capacitor in sequence; and the induced current in the sixth induced current loop passes through the second capacitor, the MOS tube of the fifth switch tube, and the parasitic diode of the sixth switch tube in sequence.

[0072] In some of the embodiments, when the resonant cavity current is zero, the current input by the photovoltaic component forms a seventh conduction current loop in the resonant circuit and generates an induced current in the voltage doubler rectifier circuit, and the induced current flows through the second capacitor of the capacitor bridge arm to form a seventh induced current loop; wherein, the current input by the photovoltaic component in the seventh conduction current loop passes through the MOS tube of the third switch tube, the LLC circuit, the MOS tube of the second switch tube and the first capacitor in sequence, and the induced current in the seventh induced current loop passes through the second capacitor, the MOS tube of the fifth switch tube, and the parasitic diode of the sixth switch tube in sequence. When the third switch tube and the second switch tube in the resonant circuit are turned off, the first switch tube and the fourth switch tube are controlled to be turned on, and the resonant cavity current in the resonant circuit feeds the first capacitor on the DC side bus to form an eighth conduction current loop, and generates an induced current in the voltage doubler rectifier circuit, and the seventh switch tube and the eighth switch tube are controlled to be turned on, and the induced current flows through the third capacitor of the capacitor bridge arm to form an eighth induced current loop; wherein, the current in the eighth conduction current loop passes through the parasitic diode of the fourth switch tube, the LLC circuit, the parasitic diode of the first switch tube, and the first capacitor in sequence, and the induced current in the eighth induced current loop passes through the MOS tube of the seventh switch tube, the parasitic diode of the eighth switch tube, and the third capacitor in sequence.

[0073] Step S204, determine that the target adjustment strategy is a phase shift angle adjustment strategy; obtain the maximum power value of the photovoltaic component and the grid voltage value in the AC power grid, and determine the output current set value corresponding to the output end of the voltage doubler rectifier circuit according to the maximum power value and the grid voltage value; determine the sine wave period corresponding to the output current of the output end of the voltage doubler rectifier circuit, and obtain the switching frequency of multiple switch tubes in the micro inverter within the sine wave period; obtain the mapping relationship between the output voltage gain and the phase shift angle, and adjust the phase shift angle between the switch tube of the first bridge arm and the switch tube of the second bridge arm in the resonant circuit according to the mapping relationship, the sine wave period and the switching frequency, so as to adjust the duty cycle of the multiple switch tubes in the voltage doubler rectifier circuit and realize the control of the output gain of the micro inverter.

[0074] The phase shift angle adjustment strategy provided by the embodiment of the present invention is: output gain control is performed by adjusting the phase shift angles corresponding to multiple switch tubes in the micro inverter.

[0075] When the output voltage value is small, that is, the output voltage value is less than the preset voltage value, since the switching frequency has been adjusted to the maximum, the output gain can no longer be reduced by increasing the switching frequency. At this time, the target adjustment strategy can be determined to adjust the phase shift angles corresponding to multiple switch tubes in the micro-inverter to further reduce the output gain. Based on this, the output gain control of the micro-inverter with a one-stage power conversion topology over a wide voltage range is realized, expanding the applicable scenarios of the micro-inverter with a one-stage power conversion topology.

[0076] In some of the embodiments, in the process of controlling the output gain of the micro inverter using the phase shift angle adjustment strategy as the target adjustment strategy in the above step S204, it also includes: keeping the switching frequency of multiple switch tubes in the micro inverter constant.

[0077] When the output voltage value is greater than or equal to the preset voltage value, the output gain can be reduced by increasing the switching frequency. However, when the output voltage value is less than the preset voltage value, the switching frequency is increased to the maximum range and the output gain can no longer be further controlled. Therefore, it is necessary to adjust the phase shift angle between the switch tube in the first bridge arm and the switch tube in the second bridge arm in the resonant circuit to further reduce the output gain. In this process, keeping the switching frequency of multiple switch tubes in the micro-inverter constant, that is, maintaining the switching frequency at the maximum switching frequency value, helps to cooperate with the phase shift angle to improve the output gain control effect, and can also simplify the complexity of the control process.

[0078] In some of the embodiments, the above-mentioned step S204 also includes the step of determining the sinusoidal wave period corresponding to the output current at the output end of the voltage doubling rectifier circuit: obtaining the grid voltage value in the AC power grid, and determining the current value of the output current according to the grid voltage value and the maximum power value of the photovoltaic component; if the current value is greater than 0, then determining that the sinusoidal wave corresponding to the output current is in the positive half-cycle of the sinusoidal wave; if the current value is less than 0, then determining that the sinusoidal wave corresponding to the output current is in the negative half-cycle of the sinusoidal wave; wherein the sinusoidal wave frequency of the output current is consistent with the sinusoidal wave frequency of the AC power in the AC power grid.

[0079] Through the above settings, combined with the current demand of the AC power grid and the maximum power value of the photovoltaic module, the sine wave period corresponding to the output current of the micro-inverter is determined, which is helpful for controlling the conduction and shutdown of multiple switching tubes in the micro-inverter based on the sine wave period. That is, by controlling the switching frequency of the switching tube, the current circuit flipping within the sine wave period is realized to output sinusoidal AC power that meets the needs of the AC power grid.

[0080] In some of the embodiments, the control method further includes: adjusting the output current phase corresponding to the output end of the voltage doubler rectifier circuit so that the phase difference between the output current phase and the grid AC phase is greater than 0, so as to achieve reactive power regulation of the micro inverter.

[0081] When the phase difference between the output current and the grid AC is 0, all active power is output at this time. When the phase difference between the output current and the grid AC is 180°, all reactive power is output at this time. Therefore, through the above settings, the phase of the output current corresponding to the output end of the voltage doubler rectifier circuit can be adjusted so that the phase difference between the output current and the grid AC is greater than 0, thereby realizing the reactive power regulation function. At the same time, the output reactive power can be adjusted by adjusting the size of the phase difference to meet the different scene requirements of the micro inverter.

[0082] In some of the embodiments, the working state of the above-mentioned multiple switch tubes is a soft switching state.

[0083] In the micro-inverter with a one-stage power conversion topology provided in the embodiment of the present invention, multiple switch tubes can operate in a soft switching state, thereby reducing switching losses and thereby improving the power generation of the micro-inverter.

[0084] The control method of the above-mentioned micro-inverter provided in the embodiment of the present invention is a micro-inverter that transmits sinusoidal AC power to the AC power grid based on a circuit topology of a first-level power conversion, by obtaining the output voltage value and the preset voltage value corresponding to the output end of the voltage doubler rectifier circuit; judging whether the output voltage value is greater than or equal to the preset voltage value; if the output voltage value is greater than or equal to the preset voltage value, determining the target adjustment strategy as the switching frequency adjustment strategy: that is, by obtaining the maximum power value of the photovoltaic component and the grid voltage value in the AC power grid, determining the output current given value corresponding to the output end of the voltage doubler rectifier circuit according to the maximum power value and the grid voltage value; obtaining the induced current value in the voltage doubler rectifier circuit, comparing the difference between the absolute value of the output current given value and the absolute value of the induced current value, and determining the switching frequencies of multiple switching tubes according to the difference to achieve control of the output gain of the micro-inverter. If the output voltage value is less than the preset voltage value, the target regulation strategy is determined to be the phase shift angle regulation strategy: that is, by obtaining the maximum power value of the photovoltaic module and the grid voltage value in the AC power grid, the output current given value corresponding to the output end of the voltage doubler rectifier circuit is determined according to the maximum power value and the grid voltage value; the sine wave period corresponding to the output current at the output end of the voltage doubler rectifier circuit is determined, and the switching frequencies of multiple switching tubes in the micro-inverter within the sine wave period are obtained; the mapping relationship between the output voltage gain and the phase shift angle is obtained, and the first bridge in the resonant circuit is adjusted according to the mapping relationship, the sine wave period and the switching frequency. The invention discloses a technical means to adjust the duty cycle of multiple switch tubes in the voltage doubling rectifier circuit by adjusting the phase shift angle between the switch tube of the first bridge arm and the switch tube of the second bridge arm, and realize the output gain control of the micro inverter; it overcomes the problems of low efficiency and power, complex control process and high cost of the micro inverter caused by adopting a two-stage power conversion circuit topology and performing corresponding output gain control in the related technology; it realizes the output gain control of the micro inverter based on the one-stage power conversion topology, improves the efficiency and power of the micro inverter, simplifies the control process of the micro inverter, and reduces the cost of the micro inverter.

[0085] The embodiment of the present invention further provides a micro inverter, comprising: at least one processor; and a memory connected to the at least one processor in communication. The memory stores a computer program executable by the at least one processor, and the computer program is used to enable an electronic device to perform the method of the embodiment of the present invention when executed by the at least one processor.

[0086] An embodiment of the present invention further provides a non-transitory machine-readable medium storing a computer program, wherein the computer program, when executed by a processor of a computer, is used to cause the computer to execute the method of the embodiment of the present invention.

[0087] An embodiment of the present invention further provides a computer program product, including a computer program, wherein the computer program, when executed by a processor of a computer, is used to enable the computer to execute the method of the embodiment of the present invention.

[0088] refer to Figure 4 , a block diagram of an electronic device that can be used as a server or client of an embodiment of the present invention will now be described, which is an example of a hardware device that can be applied to various aspects of the present invention. Electronic devices are intended to represent various forms of digital electronic computer devices, such as laptop computers, desktop computers, workbenches, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. Electronic devices can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0089] like Figure 4 As shown, the electronic device includes a computing unit 401, which can perform various appropriate actions and processes according to a computer program stored in a read-only memory (ROM) 402 or a computer program loaded from a storage unit 408 into a random access memory (RAM) 403. In RAM 403, various programs and data required for the operation of the electronic device can also be stored. The computing unit 401, ROM 402, and RAM 403 are connected to each other via a bus 404. An input / output (I / O) interface 405 is also connected to the bus 404.

[0090] Multiple components in the electronic device are connected to the I / O interface 405, including: an input unit 406, an output unit 407, a storage unit 408, and a communication unit 409. The input unit 406 can be any type of device that can input information to the electronic device, and the input unit 406 can receive input digital or character information, and generate key signal input related to user settings and / or function control of the electronic device. The output unit 407 can be any type of device that can present information, and can include but is not limited to a display, a speaker, a video / audio output terminal, a vibrator, and / or a printer. The storage unit 408 can include but is not limited to a disk, an optical disk. The communication unit 409 allows the electronic device to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks, and can include but is not limited to a modem, a network card, an infrared communication device, a wireless communication transceiver, and / or a chipset, such as a Bluetooth device, a WiFi device, a WiMax device, a cellular communication device, and / or the like.

[0091] The computing unit 401 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the computing unit 401 include, but are not limited to, a CPU, a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, digital signal processors (DSPs), and any appropriate processors, controllers, microcontrollers, etc. The computing unit 401 performs the various methods and processes described above. For example, in some embodiments, the method embodiments of the present invention may be implemented as a computer program, which is tangibly contained in a machine-readable medium, such as a storage unit 408. In some embodiments, part or all of the computer program may be loaded and / or installed on an electronic device via ROM 402 and / or communication unit 409. In some embodiments, the computing unit 401 may be configured to perform the above-described method in any other appropriate manner (e.g., by means of firmware).

[0092] The computer programs for implementing the methods of the embodiments of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when the computer programs are executed by the processor or controller, the functions / operations specified in the flow chart and / or block diagram are implemented. The computer programs may be executed entirely on the machine, partially on the machine, partially on the machine as a stand-alone software package and partially on a remote machine, or entirely on a remote machine or server.

[0093] In the context of an embodiment of the present invention, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or equipment. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable signal medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or equipment, or any suitable combination of the foregoing. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0094] It should be noted that the term "including" and its variations used in the embodiments of the present invention are open inclusions, that is, "including but not limited to". The term "based on" means "based at least in part on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments". The modifications of "one" and "multiple" mentioned in the embodiments of the present invention are illustrative rather than restrictive. Those skilled in the art should understand that unless the context clearly indicates otherwise, it should be understood as "one or more".

[0095] The various steps described in the method implementation methods provided in the embodiments of the present invention may be performed in different orders and / or in parallel. In addition, the method implementation methods may include additional steps and / or omit the steps shown. The scope of protection of the present invention is not limited in this respect.

[0096] The term "embodiment" in this specification refers to specific features, structures or characteristics described in conjunction with the embodiment that can be included in at least one embodiment of the present invention. The appearance of this phrase in various places in the specification does not necessarily mean the same embodiment, nor does it mean that it is mutually exclusive with other embodiments and is independent or optional. The various embodiments in this specification are described in a related manner, and the same or similar parts between the various embodiments refer to each other. In particular, for the device, equipment, and system embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts refer to the partial description of the method embodiment.

[0097] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of patent protection. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the attached claims.

Claims

1. A control method for a micro inverter, characterized in that: The micro inverter is used to transmit sinusoidal AC power to an AC power grid based on a circuit topology of primary power conversion. The circuit topology of the micro inverter includes: a resonant circuit, a winding transformer and a voltage doubler rectifier circuit. The resonant circuit is connected to a primary winding of the winding transformer, and the voltage doubler rectifier circuit is connected to a secondary winding of the winding transformer. The method includes: Obtaining an output voltage value corresponding to an output end of the voltage doubler rectifier circuit, and determining a target regulation strategy according to the output voltage value; According to the target adjustment strategy, multiple switch tubes in the microinverter are adjusted to control the output gain of the microinverter; the target adjustment strategy includes a switching frequency adjustment strategy and a phase shift angle adjustment strategy, wherein the switching frequency adjustment strategy is to adjust the switching frequencies corresponding to the multiple switch tubes in the microinverter, and the phase shift angle adjustment strategy is to adjust the phase shift angles corresponding to the multiple switch tubes in the microinverter.

2. The method according to claim 1, characterized in that The step of obtaining an output voltage value corresponding to the output end of the voltage doubler rectifier circuit and determining a target regulation strategy according to the output voltage value includes: Obtaining an output voltage value of an output terminal of the voltage doubler rectifier circuit, and determining whether the output voltage value is greater than or equal to a preset voltage value; If the output voltage value is greater than or equal to the preset voltage value, the target adjustment strategy is determined to be a switching frequency adjustment strategy; if the output voltage value is less than the preset voltage value, the target adjustment strategy is determined to be a phase shift angle adjustment strategy.

3. The method according to claim 2, characterized in that If the target adjustment strategy is a switching frequency adjustment strategy, the step of adjusting the plurality of switch tubes in the micro inverter to control the output gain of the micro inverter according to the target adjustment strategy includes: Acquire the maximum power value of the photovoltaic module and the grid voltage value in the AC power grid, and determine the output current given value corresponding to the output end of the voltage doubling rectifier circuit according to the maximum power value and the grid voltage value; The induced current value in the voltage doubler rectifier circuit is obtained, the difference between the absolute value of the output current given value and the absolute value of the induced current value is compared, and the switching frequencies of multiple switching tubes are determined according to the difference to achieve control of the output gain of the micro inverter.

4. The method according to claim 2, characterized in that: If the target adjustment strategy is a phase shift angle adjustment strategy, the step of adjusting a plurality of switch tubes in the micro inverter to control the output gain of the micro inverter according to the target adjustment strategy includes: Determine the sine wave period corresponding to the output current of the output end of the voltage doubler rectifier circuit, and obtain the switching frequency of multiple switch tubes in the micro inverter within the sine wave period; Obtain a mapping relationship between the output voltage gain and the phase shift angle, and adjust the phase shift angle between the switch tube in the first bridge arm and the switch tube in the second bridge arm in the resonant circuit according to the mapping relationship, the sinusoidal wave period and the switching frequency, so as to adjust the duty cycle of multiple switch tubes in the voltage doubler rectifier circuit and realize the control of the output gain of the micro inverter.

5. The method according to claim 4, characterized in that In the process of adjusting the phase shift angle between the switch tube in the first bridge arm and the switch tube in the second bridge arm in the resonant circuit, the method further includes: keeping the switching frequency of the multiple switch tubes in the micro inverter constant.

6. The method according to claim 4, characterized in that The method further comprises the step of determining a sinusoidal wave period corresponding to an output current at an output end of the voltage doubler rectifier circuit: Acquire a grid voltage value in the AC grid, and determine a current value of the output current according to the grid voltage value and a maximum power value of the photovoltaic module; If the current value is greater than 0, it is determined that the sine wave corresponding to the output current is in the positive half-cycle of the sine wave; if the current value is less than 0, it is determined that the sine wave corresponding to the output current is in the negative half-cycle of the sine wave; wherein the sine wave frequency of the output current is consistent with the sine wave frequency of the alternating current in the alternating current power grid.

7. The method according to claim 1, characterized in that The method further comprises: The output current phase corresponding to the output end of the voltage doubler rectifier circuit is adjusted so that the phase difference between the output current phase and the grid AC phase is greater than 0, so as to achieve reactive power regulation of the micro inverter.

8. The method according to claim 1, characterized in that The working state of the plurality of switch tubes is a soft switching state.

9. A micro inverter, comprising: A processor, and a memory storing a program, wherein the program comprises instructions, which, when executed by the processor, cause the processor to perform the method according to any one of claims 1 to 8.

10. A non-transitory machine-readable medium storing computer instructions, characterized in that: The computer instructions are used to cause the computer to execute the method according to any one of claims 1-8.

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