Method for controlling microinverter and related device

Abstract

The present application relates to the technical field of microinverters, and relates to a method for controlling a microinverter and a related device. A specific embodiment of the method comprises: acquiring an output voltage value corresponding to an output end of a voltage doubling rectifier circuit, and on the basis of the output voltage value, determining a target adjustment policy; on the basis of the target adjustment policy, adjusting multiple switching tubes in a microinverter so as to control an output gain of the microinverter, the microinverter being used to convey sine wave alternating current power to an alternating current power grid on the basis of a first-stage power conversion circuit topology, and the circuit topology of the microinverter comprising: a resonant circuit, a winding transformer and a voltage doubling rectifier circuit, the resonant circuit being connected to a primary winding of the winding transformer, and the voltage doubling rectifier circuit being connected to a secondary winding of the winding transformer. The present embodiment implements control of the output gain of a microinverter on the basis of a first-stage power conversion topology, improves the efficiency and power of the microinverter, and reduces the cost of the microinverter.

Description

Micro inverter control method and related equipment

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on August 30, 2023, with application number 202311116861.1, entitled “Control Method and Related Equipment for Micro Inverter”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention relates to the technical field of micro-inverters, and in particular to a control method for a micro-inverter and related equipment. Background Art

[0003] A microinverter generally refers to an inverter with a power of 1000 watts or less and module-level MPPT (Maximum Power Point Tracking) in a photovoltaic power generation system. Its full name is micro photovoltaic grid-connected inverter. "Microinverter" is used in contrast to traditional centralized inverters. Traditional photovoltaic inverters connect the direct current (DC) generated by all photovoltaic cells under sunlight in series and parallel, then use an inverter to convert the DC into AC for grid connection. Microinverters perform inversion for each module. Their advantage is independent MPPT control for each module, significantly improving overall efficiency.

[0004] Microinverters help minimize damage to photovoltaic panel panels and reduce the impact of inverter failures on photovoltaic grid-connected power generation systems. Compared with centralized inverters, they offer high reliability and lower power generation costs, making them suitable for a wide range of applications. However, current microinverter circuit topologies are primarily based on flyback circuits, which are limited by the size of the transformer core and switching frequency, resulting in low power and efficiency. To meet the demands of high-power photovoltaic modules, related technologies primarily utilize a two-stage power conversion topology to improve the power and efficiency of microinverters, and perform output gain adjustment based on this two-stage power conversion topology. Currently, there are no microinverters with a single-stage power conversion that meet the demands of high-power photovoltaic modules, nor are there any solutions for output gain control for microinverters with a single-stage power conversion.

[0005] Summary of the Invention

[0006] The embodiments of the present invention provide a micro-inverter control method and related devices, which at least solve the problem in the related art that there is no micro-inverter based on one-stage power conversion for output gain control.

[0007] To address the above-mentioned issues, one aspect of an embodiment of the present invention provides a control method for a micro-inverter. The micro-inverter is configured to transmit sinusoidal AC power to an AC grid based on a circuit topology of a primary power conversion. 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 a primary winding of the winding transformer, and the voltage-doubling rectifier circuit is connected to a secondary winding of the winding transformer. The method includes:

[0008] Obtaining an output voltage value corresponding to the output end of the voltage doubler rectifier circuit, and determining a target regulation strategy based on the output voltage value;

[0009] According to the target regulation strategy, multiple switch tubes in the micro inverter are regulated to control the output gain of the micro inverter.

[0010] In some 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:

[0011] 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;

[0012] 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.

[0013] In some embodiments, if the target adjustment strategy is to adjust the switching frequencies corresponding to multiple switching tubes in the microinverter, the step of adjusting the multiple switching tubes in the microinverter to control the output gain of the microinverter according to the target adjustment strategy includes:

[0014] Obtaining the maximum power value of the photovoltaic module and the grid voltage value in the AC 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;

[0015] The induced current value in the voltage doubler rectifier circuit is obtained, the difference between the absolute value of the output current set value and the absolute value of the induced current value is compared, and the switching frequency of multiple switching tubes is determined according to the difference to achieve the output gain control of the micro inverter.

[0016] In some embodiments, if the target adjustment strategy is a phase shift angle corresponding to a plurality of switching tubes in a microinverter, the step of adjusting the plurality of switching tubes in the microinverter to control the output gain of the microinverter according to the target adjustment strategy includes:

[0017] Determine the sine wave period corresponding to the output current at the output end of the voltage doubler rectifier circuit, and obtain the switching frequencies of multiple switching tubes in the micro inverter within the sine wave period;

[0018] The mapping relationship between the output voltage gain and the phase shift angle is obtained. According to the mapping relationship, the sine wave period and the switching frequency, 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 is adjusted 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.

[0019] In some embodiments, during the process of adjusting the phase shift angle between the switch in the first bridge arm and the switch in the second bridge arm in the resonant circuit, the method further includes: maintaining a constant switching frequency of the multiple switch tubes in the micro-inverter.

[0020] In some embodiments, the method further includes the step of determining a sinusoidal wave period corresponding to an output current at an output end of the voltage doubler rectifier circuit:

[0021] Obtaining a grid voltage value in the AC grid, and determining an output current value based on the grid voltage value and a maximum power value of the photovoltaic module;

[0022] 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 AC power in the AC power grid.

[0023] In some embodiments, the method further comprises:

[0024] 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, thereby achieving reactive power regulation of the micro inverter.

[0025] In some embodiments, the operating state of the multiple switch tubes is a soft switching state.

[0026] 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, which, when executed by the processor, enable the processor to execute any of the above-mentioned micro inverter control methods.

[0027] In order to solve the above problem, 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.

[0028] The beneficial effects of the embodiments of the present invention are as follows: 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 regulation strategy based on the output voltage value; according to the target regulation strategy, multiple switches in the micro-inverter are regulated 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. This overcomes the problems of low efficiency and power, complex control process, and high cost of micro-inverters caused by the use of a two-stage power conversion circuit topology and the corresponding output gain control in the related art; output gain control of a micro-inverter based on a first-stage power conversion topology is realized, thereby improving the efficiency and power of the micro-inverter, simplifying the control process of the micro-inverter, and reducing the cost of the micro-inverter.

[0029] The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below so that other features, objects, and advantages of the invention are more readily apparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] 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 description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] FIG1 is a flow chart of a method for controlling a micro-inverter according to an embodiment of the present invention.

[0032] FIG2 is a flow chart of a control method for a micro-inverter according to another embodiment of the present invention.

[0033] FIG3 is a schematic diagram of the electrical topology of a micro-inverter with a one-stage power conversion topology according to an embodiment of the present invention.

[0034] FIG4 is a schematic structural diagram of the electronic device of this embodiment. DETAILED DESCRIPTION

[0035] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0036] The terms "first," "second," and the like in the specification, claims, and accompanying drawings of this application are used to distinguish between different objects, not to describe a particular order. Furthermore, the terms "including," "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements, but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0037] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0038] The current microinverter circuit topology is primarily based on a flyback circuit. The secondary side of the transformer converts the output current into AC through a folded circuit. This circuit topology is limited by the transformer core volume and switching frequency, making it difficult to increase the power output and resulting in low inverter efficiency. As the power of photovoltaic modules increases, microinverters are required to increase their power and efficiency. Most microinverters in related technologies use two-stage power conversion technology. However, the total efficiency of the microinverter in two-stage power conversion is equal to the product of the two conversion efficiencies, making it difficult for microinverters to exceed 96% efficiency. That is, although related technologies improve the power and efficiency of microinverters by using a two-stage power conversion topology and perform output gain adjustment based on the two-stage power conversion topology, it still cannot meet the needs of high-power photovoltaic modules. Furthermore, the control process of microinverters is complex and the cost is high.

[0039] To solve the above problems, an embodiment of the present invention provides a micro-inverter control method. The micro-inverter control method is applied to a micro-inverter based on a one-stage power conversion topology. As shown in FIG1 , the micro-inverter control method includes:

[0040] Step S101 : obtaining an output voltage value corresponding to an output terminal of a voltage-doubling rectifier circuit, and determining a target regulation strategy according to the output voltage value.

[0041] The micro-inverter provided in an embodiment of the present invention is used to transmit sinusoidal AC power to an AC power grid based on a circuit topology with a first-stage power conversion. 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. Through the above arrangement, the embodiment of the present invention adjusts the output gain of the micro-inverter according to a target adjustment strategy based on the output voltage value by obtaining the output voltage value corresponding to the output terminal of the voltage-doubling rectifier circuit. This improves the output gain adjustment effect and helps to increase the power and efficiency of the micro-inverter with a first-stage power conversion topology.

[0042] In some embodiments, the target adjustment strategy includes a switching frequency adjustment strategy and a phase shift angle adjustment strategy. The switching frequency adjustment strategy is to control the output gain by adjusting the switching frequencies corresponding to multiple switching tubes in the microinverter; the phase shift angle adjustment strategy is to control the output gain by adjusting the phase shift angles corresponding to multiple switching tubes in the microinverter. The steps of obtaining the output voltage value corresponding to the output terminal of the voltage doubler rectifier circuit and determining the target adjustment strategy based on the output voltage value include: obtaining the output voltage value of the output terminal of the voltage doubler rectifier circuit, 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, determining that the target adjustment strategy is the switching frequency adjustment strategy; if the output voltage value is less than the preset voltage value, determining that the target adjustment strategy is the phase shift angle adjustment strategy.

[0043] 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.

[0044] 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.

[0045] Based on the above target adjustment strategy, multiple switching tubes in the micro inverter are adjusted to achieve output gain control, which reduces the complexity of the output gain control process and helps reduce the cost of the micro inverter.

[0046] The above steps specifically disclose the specific steps of determining the target regulation strategy based on 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 regulation strategy is determined to be the switching frequency regulation strategy, that is, the output gain is controlled by adjusting the switching frequencies corresponding to the 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 regulation strategy can be determined to be the phase shift angle regulation strategy, that is, the output gain is controlled by adjusting the phase shift angles corresponding to the 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 one-stage power conversion topology, expanding the applicable scenarios of micro-inverters with a one-stage power conversion topology.

[0047] In some embodiments, if the target adjustment strategy is a switching frequency adjustment strategy, the step of adjusting the switching frequencies corresponding to the 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.

[0048] The above steps provide specific operational implementations for adjusting the output gain of a microinverter by adjusting the switching frequencies corresponding to multiple switches in the microinverter. This embodiment of the present invention controls the output gain of a microinverter based on a single-stage power conversion topology, where the output of the microinverter provides sinusoidal AC power to an AC 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. When the photovoltaic module meets the maximum power value, the current input by the photovoltaic module is received, and then the output current set value is determined in combination with the grid voltage value in the AC grid. The output current set value is processed by taking the absolute value and used as the target set signal of the drive controller. At the same time, the induced current value in the secondary winding of the voltage-doubling rectifier circuit is obtained and processed by taking the absolute value and filtering to use as the feedback signal of the output current sampling. The feedback signal of the output current sampling is compared with the target set signal of the drive controller to determine the signal difference. The signal difference is PI-regulated by a proportional integral controller (PI) to form a current loop control signal. The current loop control signal is then processed by a voltage-frequency converter to output a frequency-adjustable drive signal to adjust the switching frequency of multiple switching tubes in the micro-inverter, thereby controlling the output gain of the micro-inverter and improving the power and efficiency of the micro-inverter. The above difference is adjusted by the PI regulator, and the switching frequency corresponding to the switching 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.

[0049] In some embodiments, if the target adjustment strategy is a phase shift angle adjustment strategy, the step of adjusting the phase shift angles 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: 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 switching tubes in the micro-inverter within the sinusoidal wave period; obtaining a mapping relationship between the output voltage gain and the phase shift angle, and adjusting the phase shift angle between the switching tube in the first bridge arm and the switching tube in the second bridge arm in the resonant circuit according to the mapping relationship, the sinusoidal wave period and the switching frequency to adjust the duty cycle of the multiple switching tubes in the voltage doubler rectifier circuit and control the output gain of the micro-inverter.

[0050] The above steps provide a specific operational implementation for adjusting the output gain of a microinverter by adjusting the phase shift angles corresponding to multiple switches in the microinverter. By combining the output current's sinusoidal wave period, the constant switching frequency, and the mapping relationship between the output voltage gain and the phase shift angle, the phase shift angle between the switches in the first and second bridge arms of the resonant circuit corresponding to the microinverter's primary side is adjusted, effectively reducing the equivalent duty cycle of the switches in the voltage-doubling rectifier circuit corresponding to the microinverter's secondary side, thereby reducing the output gain. The mapping relationship between the output voltage gain and the phase shift angle provided in this embodiment of the present invention can be determined using a pre-set mapping relationship table. Alternatively, a desired output gain and an actual output gain can be obtained, and the output gain difference between the two can be determined. A PI controller can then be sampled to output the gain difference for PI regulation. After the output gain difference is regulated by the PI regulator, the corresponding phase shift angle value is output. When the desired output gain is greater than the actual output gain, i.e., the output gain difference is positive, the output phase shift angle value decreases; when the desired output gain is less than the actual output gain, i.e., the output gain difference is negative, the output phase shift angle value increases.

[0051] In some embodiments, during the process of adjusting the phase shift angle between the switch in the first bridge arm and the switch in the second bridge arm in the resonant circuit, the method further includes: maintaining a constant switching frequency of the multiple switch tubes in the micro-inverter.

[0052] 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 work together with the phase shift angle to improve the output gain control effect, and can also simplify the complexity of the control process.

[0053] In some embodiments, the above method also includes a 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 based on 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 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.

[0054] 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 microinverter is determined. This helps to control the conduction and shutdown of multiple switching tubes in the microinverter based on the sine wave period. That is, by controlling the switching frequency of the switching tube, the current circuit within the sine wave period is flipped to output sinusoidal AC power that meets the requirements of the AC power grid.

[0055] In some 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.

[0056] When the phase difference between the output current and the grid AC power is 0, all active power is output. When the phase difference between the output current and the grid AC power is 180°, all reactive power is output. Therefore, through the above settings, the reactive power regulation function can be achieved by adjusting the phase of the output current corresponding to the output end of the voltage doubler rectifier circuit so that the phase difference between the output current and the grid AC power is greater than 0. At the same time, the output reactive power can also be adjusted by adjusting the size of the phase difference to meet the different scenarios of the micro inverter.

[0057] In some embodiments, the operating state of the plurality of switch tubes is a soft switching state.

[0058] In the micro-inverter with a one-stage power conversion topology provided by the embodiment of the present invention, multiple switching tubes can operate in a soft switching state, thereby reducing switching losses and thereby increasing the power generation capacity of the micro-inverter.

[0059] The control method for the micro-inverter provided in an embodiment of the present invention is a micro-inverter that transmits sinusoidal AC power to an AC grid based on a circuit topology of a first-stage power conversion. The method obtains the output voltage value corresponding to the output terminal of a voltage-doubling rectifier circuit and determines a target regulation strategy based on the output voltage value; according to the target regulation strategy, multiple switches in the micro-inverter are regulated to control the output gain of the micro-inverter. The circuit topology of the micro-inverter includes a resonant circuit, a winding transformer, and a voltage-doubling rectifier circuit, wherein 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. This method overcomes the problems of low efficiency and power, complex control process, and high cost of micro-inverters caused by the use of a two-stage power conversion circuit topology and the corresponding output gain control in related technologies. The method implements output gain control of a micro-inverter based on a first-stage power conversion topology, thereby improving the efficiency and power of the micro-inverter, simplifying the control process of the micro-inverter, and reducing the cost of the micro-inverter.

[0060] To solve the above problem, another embodiment of the present invention provides a control method for a micro-inverter. The control method for the micro-inverter is applied to a micro-inverter based on a one-stage power conversion topology. As shown in FIG2 , the control method for the micro-inverter includes:

[0061] Step S201 , obtaining an output voltage value and a preset voltage value corresponding to an output terminal of a voltage doubler rectifier circuit.

[0062] 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 one-stage power conversion. Figure 3 shows a circuit topology schematic diagram of the micro-inverter in the embodiment of the present invention. As shown in Figure 3, 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.

[0063] 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. 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. The induced current flows through the capacitor in the capacitor bridge arm to form an induced current loop and achieve a 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.

[0064] In some embodiments, as shown in FIG3 , 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 transistor Q1 and a second switch transistor Q2 connected in series, and the second bridge arm includes a third switch transistor Q3 and a fourth switch transistor Q4 connected in series; the LLC circuit includes a leakage inductor Lr, an excitation inductor Lm, and a resonant capacitor Cr connected in series, wherein the excitation inductor Lm also represents 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.

[0065] In some embodiments, as shown in FIG3 , the switch arm in the voltage-doubling rectifier circuit includes an upper switch arm and a lower switch arm, wherein the upper switch arm includes a fifth switch transistor Q5 and a sixth switch transistor Q6 connected in series and arranged in a mirrored manner, and the lower switch arm includes a seventh switch transistor Q7 and an eighth switch transistor Q8 connected in series and arranged in a mirrored manner. The capacitor arm in the voltage-doubling 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 arm, and the other end of the secondary winding is connected to the midpoint of the capacitor arm. A filter inductor Lg is provided at the output end of the voltage-doubling rectifier circuit. The filter inductor Lg can be provided on one side of the output end of the voltage-doubling rectifier circuit, or on both sides of the output end of the voltage-doubling rectifier circuit. Furthermore, the filter inductor can be provided at the output end of the voltage-doubling rectifier circuit in the form of a common-mode inductor. In the embodiment of the present invention, 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 form an LC high-frequency filter circuit, thereby achieving a filtering processing effect on the output current.

[0066] The micro-inverter applied based on the embodiment of the present invention realizes a circuit topology based on primary power conversion to transmit sinusoidal AC power to the AC grid, thereby effectively improving the efficiency and power of the micro-inverter.

[0067] Step S202: Determine whether the output voltage is greater than or equal to a preset voltage. If so, that is, the output voltage is greater than or equal to the preset voltage, proceed to step S203; if not, that is, the output voltage is less than the preset voltage, proceed to step S204.

[0068] 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 value of the preset voltage value is a positive number.

[0069] Through the above-mentioned setting, 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 magnitude 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 one-stage power conversion topology and improves the output gain adjustment effect.

[0070] Step S203, determining that the target regulation strategy is a switching frequency regulation strategy; obtaining the maximum power value of the photovoltaic module 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 based on 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 frequency of multiple switching tubes based on the difference to achieve control of the output gain of the micro inverter.

[0071] The switching frequency adjustment strategy provided by the embodiments of the present invention is to control output gain by adjusting the switching frequencies corresponding to multiple switches in the microinverter. When the output voltage is high, that is, the output voltage is greater than or equal to a preset voltage value, the switching frequency of the switch 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, which adjusts the switching frequencies corresponding to multiple switches in the microinverter.

[0072] The above steps provide specific operational implementations for adjusting the output gain of a microinverter by adjusting the switching frequencies corresponding to multiple switches in the microinverter. This embodiment of the present invention controls the output gain of a microinverter based on a single-stage power conversion topology, where the output of the microinverter provides sinusoidal AC power to an AC 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. When the photovoltaic module meets the maximum power value, the current input by the photovoltaic module is received. Then, an output current set value is determined in combination with the grid voltage value in the AC grid. The output current set value is processed by taking the absolute value and used as the target set signal of the drive controller. At the same time, the induced current value in the secondary winding of the voltage-doubling rectifier circuit is obtained and also processed by taking the absolute value and filtering to use it as the feedback signal of the output current sampling. The feedback signal of the output current sampling is compared with the target set signal of the drive controller to determine the signal difference. The signal difference is PI-regulated by a PI regulator to form a current loop control signal. The current loop control signal is then processed by a voltage-frequency converter to output a frequency-adjustable drive signal to adjust the switching frequency of multiple switching tubes in the micro-inverter, thereby controlling the output gain of the micro-inverter and improving 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.

[0073] In some 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, controlling 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 and fourth switching tubes in the resonant circuit are turned off, and the third and second switching tubes are controlled to be turned on, the resonant cavity current in the resonant circuit feeds the first capacitor on the DC bus to form a second conduction current loop, and forms an induced current in the voltage doubler rectifier circuit. The seventh and eighth switching tubes 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. The resonant cavity current in the second conduction current loop passes through the parasitic diode of the third switching tube, the first capacitor, the parasitic diode of the second switching tube, and the LLC circuit in sequence. The induced current in the second induced current loop passes through the third capacitor, the MOS tube of the eighth switching tube, and the parasitic diode of the seventh switching tube in sequence.

[0074] In some 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. 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 and second switching tubes in the resonant circuit are turned off, the first and fourth switching tubes are controlled to be turned on, and the resonant cavity current in the resonant circuit is fed to the first capacitor on the DC side bus to form a fourth conduction current loop, and an induced current is generated in the voltage doubler rectifier circuit. The fifth and sixth switching tubes 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 switching tube, the LLC circuit, the parasitic diode of the first switching 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 switching tube, the parasitic diode of the fifth switching tube, and the second capacitor in sequence.

[0075] In some embodiments, if the sinusoidal wave period of the output current is the negative half-cycle 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, controlling 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; and 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 and fourth switching tubes in the resonant circuit are turned off and the third and second switching tubes are turned on, the resonant cavity current in the resonant circuit feeds the first capacitor on the DC bus to form a sixth conduction current loop, and forms an induced current in the voltage doubler rectifier circuit, which controls the fifth and sixth switching tubes to be turned on. 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 switching tube, the LLC circuit, the parasitic diode of the third switching 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 switching tube, and the parasitic diode of the sixth switching tube in sequence.

[0076] In some 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 and second switching tubes in the resonant circuit are turned off, the first and fourth switching tubes are controlled to be turned on, and the resonant cavity current in the resonant circuit is fed to the first capacitor on the DC bus to form an eighth conduction current loop, and an induced current is generated in the voltage doubler rectifier circuit. The seventh and eighth switching tubes 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 switching tube, the LLC circuit, the parasitic diode of the first switching 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 switching tube, the parasitic diode of the eighth switching tube, and the third capacitor in sequence.

[0077] Step S204, determining that the target regulation strategy is a phase shift angle regulation strategy; 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; determining the sine wave period corresponding to the output current of the output end of the voltage doubler rectifier circuit, and obtaining the switching frequency of multiple switching tubes in the micro-inverter within the sine wave period; obtaining a mapping relationship between the output voltage gain and the phase shift angle, and adjusting the phase shift angle between the switching tube of the first bridge arm and the switching 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 switching tubes in the voltage doubler rectifier circuit and realize the control of the output gain of the micro-inverter.

[0078] The phase shift angle adjustment strategy provided by the embodiment of the present invention is to control the output gain by adjusting the phase shift angles corresponding to the multiple switching tubes in the micro-inverter.

[0079] When the output voltage is low—that is, below the preset voltage—the switching frequency has already been adjusted to its maximum, making it impossible to further reduce the output gain by increasing it. In this case, the target regulation strategy is to adjust the phase shift angles corresponding to the multiple switches in the microinverter to further reduce the output gain. This enables output gain control over a wide voltage range for microinverters with a one-stage power conversion topology, expanding the application scenarios of microinverters with this topology.

[0080] In some 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 step S204, the process further includes: maintaining a constant switching frequency of multiple switching tubes in the micro-inverter.

[0081] 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 work together with the phase shift angle to improve the output gain control effect, and can also simplify the complexity of the control process.

[0082] In some 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 doubler rectifier circuit: obtaining the grid voltage value in the AC power grid, and determining the current value of the output current based on 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.

[0083] 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 microinverter is determined. This helps to control the conduction and shutdown of multiple switching tubes in the microinverter based on the sine wave period. That is, by controlling the switching frequency of the switching tube, the current circuit within the sine wave period is flipped to output sinusoidal AC power that meets the requirements of the AC power grid.

[0084] In some 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.

[0085] When the phase difference between the output current and the grid AC power is 0, all active power is output. When the phase difference between the output current and the grid AC power is 180°, all reactive power is output. Therefore, through the above settings, the reactive power regulation function can be achieved by adjusting the phase of the output current corresponding to the output end of the voltage doubler rectifier circuit so that the phase difference between the output current and the grid AC power is greater than 0. At the same time, the output reactive power can also be adjusted by adjusting the size of the phase difference to meet the different scenarios of the micro inverter.

[0086] In some embodiments, the operating state of the plurality of switch tubes is a soft switching state.

[0087] In the micro-inverter with a one-stage power conversion topology provided by the embodiment of the present invention, multiple switching tubes can operate in a soft switching state, thereby reducing switching losses and thereby increasing the power generation capacity of the micro-inverter.

[0088] The control method for the above-mentioned micro-inverter provided in an embodiment of the present invention is a micro-inverter that transmits sinusoidal AC power to an AC power grid based on a circuit topology of a first-stage power conversion. The method obtains the output voltage value and a preset voltage value corresponding to the output end of a voltage-doubling rectifier circuit; determines 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, determines that the target regulation strategy is a switching frequency 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 set value corresponding to the output end of the voltage-doubling rectifier circuit is determined according to the maximum power value and the grid voltage value; obtains the induced current value in the voltage-doubling rectifier circuit, compares the difference between the absolute value of the output current set value and the absolute value of the induced current value, and determines the switching frequency 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 of the output end of the voltage doubler rectifier circuit is determined, and the switching frequency of multiple switching tubes in the micro inverter within the sine wave period is 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 for adjusting the duty cycle of multiple switching tubes in the voltage doubling rectifier circuit by adjusting the phase shift angle between the switching tube of the first bridge arm and the switching tube of the second bridge arm, thereby overcoming the problems of low efficiency and power, complex control process and high cost of the micro-inverter caused by the use of a two-stage power conversion circuit topology and corresponding output gain control in the related art; and realizes output gain control of the micro-inverter based on the one-stage power conversion topology, thereby improving the efficiency and power of the micro-inverter, simplifying the control process of the micro-inverter and reducing the cost of the micro-inverter.

[0089] An embodiment of the present invention further provides a micro-inverter, comprising: at least one processor; and a memory communicatively connected to the at least one processor. The memory stores a computer program executable by the at least one processor, wherein the computer program, when executed by the at least one processor, causes an electronic device to perform the method of an embodiment of the present invention.

[0090] 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 perform the method of the embodiment of the present invention.

[0091] An embodiment of the present invention further provides a computer program product, including a computer program, wherein when the computer program is executed by a processor of a computer, it is used to enable the computer to perform the method of the embodiment of the present invention.

[0092] With reference 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. The electronic device is intended to represent various forms of digital electronic computer equipment, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device 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.

[0093] As shown in Figure 4, 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.

[0094] Multiple components within 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 capable of inputting information into the electronic device. The input unit 406 can receive input numeric or character information and generate key signal inputs related to user settings and / or function control of the electronic device. The output unit 407 can be any type of device capable of presenting 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 magnetic disk or an optical disk. The communication unit 409 allows the electronic device to exchange information / data with other devices via 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.

[0095] 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 that run 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).

[0096] 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 flowcharts and / or block diagrams are implemented. The computer programs may be executed entirely on the machine, partially on the machine, as a stand-alone software package, partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0097] In the context of an embodiment of the present invention, a machine-readable medium can be a tangible medium that can contain or store a program for use by an instruction execution system, device or equipment or used in combination with an instruction execution system, device or equipment. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. A machine-readable signal medium can 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 can 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.

[0098] It should be noted that the term "including" and its variations used in the embodiments of the present invention are open-ended, i.e., "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"; and the term "some embodiments" means "at least some embodiments." The modifications of "one" and "a plurality of" mentioned in the embodiments of the present invention are illustrative and non-restrictive. Those skilled in the art should understand that, unless the context clearly indicates otherwise, they should be understood as "one or more."

[0099] The various steps described in the method implementation scheme provided in the embodiments of the present invention may be performed in different orders and / or in parallel. In addition, the method implementation scheme may include additional steps and / or omit the steps shown. The scope of protection of the present invention is not limited in this respect.

[0100] 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 are referenced to each other. In particular, for the embodiments of the device, equipment, and system, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts are referred to the partial description of the method embodiment.

[0101] The specific embodiments described above further illustrate the objectives, technical solutions, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

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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