Photovoltaic inverter control method and device, and photovoltaic inverter

Abstract

The invention discloses a control method and device of a photovoltaic inverter and the photovoltaic inverter. The method comprises the following steps: determining a voltage period of operation of the photovoltaic inverter, the voltage period comprising a positive half period and a negative half period; under the condition that the photovoltaic inverter works in a positive half cycle, the photovoltaic inverter is controlled to operate a first conversion circuit in the plurality of conversion circuits, and the photovoltaic inverter is controlled to work in a first type of mode corresponding to the positive half cycle, and under the condition that the photovoltaic inverter works in a negative half cycle, the photovoltaic inverter is controlled to operate in a second type of mode corresponding to the negative half cycle. And controlling the photovoltaic inverter to operate a second conversion circuit in the plurality of conversion circuits, and controlling the photovoltaic inverter to work in a second type of mode corresponding to a negative half cycle, and when the photovoltaic inverter works in different modes, semiconductor devices in the photovoltaic inverter, which are in conduction states, are different. According to the invention, the technical problem that a photovoltaic inverter which can be directly applied to a low-voltage input scene is lacked in the prior art is solved.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a control method and device for a photovoltaic inverter, and a photovoltaic inverter. Background Art

[0002] Solar energy, hydropower, wind energy, etc. as new energy sources have received extensive attention in the current energy development with the goal of energy conservation and emission reduction. Among them, inverter technology is one of the key technologies in the field of new energy power generation. According to the different power generation objects, inverters are divided into photovoltaic inverters, wind power inverters, power equipment inverters, etc. At present, the mainstream inverters used in photovoltaic systems are step-down pulse width modulation inverters (Buck type PWM inverters). When this type of inverter is working, its input DC voltage must be greater than the peak value of the AC side voltage. Therefore, Buck type PWM inverters cannot be directly applied to low-voltage input scenarios; in addition, Buck type PWM inverters contain a large number of diode power tubes. The more power tubes and diodes there are, the higher the temperature rise caused by the loss of power tubes and diodes, resulting in excessive overall temperature rise of the photovoltaic inverter, reducing the efficiency and service life of the photovoltaic inverter.

[0003] To address the above-mentioned problems, no effective solution has been proposed yet. Summary of the invention

[0004] The embodiments of the present application provide a control method and device for a photovoltaic inverter, and a photovoltaic inverter, so as to at least solve the technical problem in the related art that there is a lack of a photovoltaic inverter that can be directly applied in a low-voltage input scenario.

[0005] According to one aspect of an embodiment of the present application, a control method for a photovoltaic inverter is provided, the method being applied to a photovoltaic inverter, the photovoltaic inverter comprising: a power supply, a plurality of conversion circuits for converting an input voltage, wherein the input voltage is a voltage output by the power supply, and the plurality of conversion circuits share the following elements: a power supply, a first inductor connected to the power supply, a first power tube and a second power tube connected in parallel with the first inductor; the control method for the photovoltaic inverter comprising: determining a voltage cycle in which the photovoltaic inverter operates, wherein the voltage cycle comprises: a positive half cycle and a negative half cycle; when the photovoltaic inverter operates in a positive half cycle, controlling the photovoltaic inverter to operate a first conversion circuit among the plurality of conversion circuits, and controlling the photovoltaic inverter to operate in a first type of mode corresponding to the positive half cycle; when the photovoltaic inverter operates in a negative half cycle, controlling the photovoltaic inverter to operate a second conversion circuit among the plurality of conversion circuits, and controlling the photovoltaic inverter to operate in a second type of mode corresponding to the negative half cycle, wherein when the photovoltaic inverter operates in different modes, different semiconductor devices in the photovoltaic inverter are in a conductive state.

[0006] Optionally, the photovoltaic inverter further includes: a filter circuit, wherein the filter circuit is connected to the first conversion circuit through a third power tube in the photovoltaic inverter, and the filter circuit is connected to the second conversion circuit through a fourth power tube in the photovoltaic inverter.

[0007] Optionally, the first conversion circuit includes: a power supply, a first inductor, multiple semiconductor devices, and a filter circuit, wherein the multiple semiconductor devices include: a first diode, multiple power tubes, and the multiple power tubes include: a first power tube, a second power tube, a third power tube, and a fifth power tube, wherein the first power tube is connected to the first inductor and the third power tube, the second power tube is connected to the collector of the first inductor and the fifth power tube, the fifth power tube is connected to the second power tube and the negative electrode of the power supply, and the two ends of the first diode are respectively connected to the second power tube and the filter circuit.

[0008] Optionally, the first type of mode includes: a first mode and a second mode, wherein, when the photovoltaic inverter operates in the first mode and the second mode, the number of current loops is different; controlling the photovoltaic inverter to operate in the first type of mode corresponding to the positive half cycle includes: determining a first instantaneous value of a carrier signal and a second instantaneous value of a modulation signal, wherein the carrier signal is used to control the output of the photovoltaic inverter, and the modulation signal is used to modulate the first power tube and the second power tube; when the first instantaneous value is greater than the second instantaneous value, controlling the photovoltaic inverter to operate in the first mode; when the first instantaneous value is less than the second instantaneous value, controlling the photovoltaic inverter to operate in the second mode.

[0009] Optionally, controlling the photovoltaic inverter to operate in a first mode includes: controlling the states of all power tubes in the first conversion circuit to be on, and controlling the states of other power tubes of the first type to be off, wherein the other power tubes of the first type are power tubes that do not belong to the first conversion circuit among all power tubes contained in the photovoltaic inverter; controlling the photovoltaic inverter to operate in a second mode includes: controlling the state of the second power tube to be off, controlling the state of other power tubes of the second type to be on, and controlling the state of other power tubes of the first type to be off, wherein the other power tubes of the second type are power tubes in the first conversion circuit other than the second power tube.

[0010] Optionally, the second conversion circuit includes: a power supply, a first inductor, multiple semiconductor devices, and a filter circuit, wherein the multiple semiconductor devices include: a second diode, multiple power tubes, wherein the multiple power tubes include: a first power tube, a second power tube, a fourth power tube and a sixth power tube, wherein the first power tube and the second power tube are connected in parallel with the first inductor, the fourth power tube is connected to the second power tube and the filter circuit, the sixth power tube is connected to the first power tube and the negative pole of the power supply, and the two ends of the second diode are respectively connected to the first power tube and the filter circuit.

[0011] Optionally, the second mode includes: a third mode and a fourth mode, wherein the number of current loops is different when the photovoltaic inverter operates in the third mode and the fourth mode; controlling the photovoltaic inverter to operate in the second mode corresponding to the negative half-cycle includes: determining a first instantaneous value of a carrier signal and a second instantaneous value of a modulation signal, wherein the carrier signal is used to control the output of the photovoltaic inverter, and the modulation signal is used to modulate the first power tube and the second power tube; when the first instantaneous value is greater than the second instantaneous value, controlling the photovoltaic inverter to operate in the third mode; when the first instantaneous value is less than the second instantaneous value, controlling the photovoltaic inverter to operate in the fourth mode.

[0012] Optionally, controlling the photovoltaic inverter to operate in a third mode includes: controlling the state of all power tubes in the second conversion circuit to be on, and controlling the state of other power tubes of the third category to be off, wherein the other power tubes of the third category are power tubes that do not belong to the second conversion circuit among all power tubes contained in the photovoltaic inverter; controlling the photovoltaic inverter to operate in a fourth mode includes: controlling the state of the first power tube to be off, controlling the state of other power tubes of the fourth category to be on, and controlling the state of other power tubes of the third category to be off, wherein the other power tubes of the fourth category are power tubes other than the first power tube in the second conversion circuit.

[0013] Optionally, determining the voltage cycle of the photovoltaic inverter includes: determining the phase of a modulation signal, wherein the modulation signal is used to modulate the first power tube and the second power tube; when the phase is greater than 0, determining that the voltage cycle of the photovoltaic inverter is a positive half-cycle; when the phase is less than 0, determining that the voltage cycle of the photovoltaic inverter is a negative half-cycle.

[0014] According to another aspect of an embodiment of the present application, a photovoltaic inverter is also provided, which includes: a power supply, multiple conversion circuits for converting an input voltage, and a filter circuit, wherein the input voltage is the voltage output by the power supply; the multiple conversion circuits share the following elements: a power supply, a first inductor connected to the power supply, a first power tube and a second power tube connected in parallel with the first inductor, wherein the first inductor remains in a conductive state during the operation of the photovoltaic inverter; the filter circuit is connected to the multiple conversion circuits through the third power tube and the fourth power tube in the photovoltaic inverter respectively.

[0015] According to another aspect of an embodiment of the present application, a control device for a photovoltaic inverter is also provided, which is applied to a photovoltaic inverter, wherein the photovoltaic inverter includes: a power supply, a plurality of conversion circuits for converting an input voltage, wherein the input voltage is a voltage output by the power supply, and the plurality of conversion circuits share the following elements: a power supply, a first inductor connected to the power supply, a first power tube and a second power tube connected in parallel with the first inductor; the control device for the photovoltaic inverter includes: a determination module, which is used to determine a voltage cycle of operation of the photovoltaic inverter, wherein the voltage cycle includes: a positive half cycle and a negative half cycle; a control module, which is used to control the photovoltaic inverter to operate a first conversion circuit among the plurality of conversion circuits when the photovoltaic inverter operates in a positive half cycle, and to control the photovoltaic inverter to operate in a first type of mode corresponding to the positive half cycle, and to control the photovoltaic inverter to operate in a second type of mode corresponding to the negative half cycle when the photovoltaic inverter operates in a negative half cycle, wherein when the photovoltaic inverter operates in different modes, the semiconductor devices in the photovoltaic inverter that are in a conductive state are different.

[0016] According to another aspect of an embodiment of the present application, a non-volatile storage medium is further provided, in which a computer program is stored, wherein the above-mentioned photovoltaic inverter control method is executed by running the computer program on a device where the non-volatile storage medium is located.

[0017] According to another aspect of an embodiment of the present application, there is also provided an electronic device, including a memory and a processor, wherein a computer program is stored in the memory, and the processor is configured to execute the above-mentioned photovoltaic inverter control method through the computer program.

[0018] According to another aspect of the embodiments of the present application, a computer program product is further provided, including computer instructions, which implement the steps of the above-mentioned photovoltaic inverter control method when executed by a processor.

[0019] In an embodiment of the present application, a control method for a photovoltaic inverter is provided, wherein the photovoltaic inverter includes: a power supply, a plurality of conversion circuits for converting an input voltage, wherein the input voltage is a voltage output by the power supply, and the plurality of conversion circuits share the following elements: a power supply, a first inductor connected to the power supply, a first power tube and a second power tube connected in parallel with the first inductor; when controlling the above-mentioned photovoltaic inverter, a voltage cycle for determining the operation of the photovoltaic inverter is adopted, wherein the voltage cycle includes: a positive half cycle and a negative half cycle; when the photovoltaic inverter operates in a positive half cycle, the photovoltaic inverter is controlled to operate a first conversion circuit among the plurality of conversion circuits, and the photovoltaic inverter is controlled to operate in a first type of mode corresponding to the positive half cycle; when the photovoltaic inverter operates in a negative half cycle, the photovoltaic inverter is controlled to operate a second conversion circuit among the plurality of conversion circuits, and the photovoltaic inverter is controlled to operate in a second type of mode corresponding to the negative half cycle, wherein when the photovoltaic inverter operates in different modes, the states in the photovoltaic inverter are changed. In a different way of conducting semiconductor devices, fewer components are used to construct a photovoltaic inverter including a circuit capable of realizing a boost function (i.e., a first conversion circuit and a second conversion circuit). The number of components in the photovoltaic inverter is reduced by sharing components, the hardware cost and volume of the photovoltaic inverter are reduced, the temperature rise of the photovoltaic inverter during application is reduced, and the integration and reliability of the system are improved. When the photovoltaic inverter provided by the embodiment of the present application is applied, the working mode of the circuit under different voltage cycles is adjusted to ensure that the circuit can realize the boost function. Therefore, the photovoltaic inverter provided by the embodiment of the present application can be applied in low-voltage input scenarios, thereby achieving the technical effect of providing a photovoltaic inverter that can be directly applied in low-voltage input scenarios. At the same time, since only the working mode of the circuit under different voltage cycles needs to be adjusted, the technical effect of optimizing the power conversion efficiency of the inverter is also achieved, thereby solving the technical problem of the lack of photovoltaic inverters that can be directly applied in low-voltage input scenarios in the related art. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0021] Figure 1 is an internal circuit diagram of a photovoltaic inverter according to an embodiment of the present application;

[0022] Figure 2 is a flowchart of a method for controlling a photovoltaic inverter according to an embodiment of the present application;

[0023] Figure 3 is a circuit diagram of a photovoltaic inverter operating in a first mode according to an embodiment of the present application;

[0024] Figure 4 is a circuit diagram of a photovoltaic inverter operating in a second mode according to an embodiment of the present application;

[0025] Figure 5 is a circuit diagram of a photovoltaic inverter operating in a third mode according to an embodiment of the present application;

[0026] Figure 6 is a circuit diagram of a photovoltaic inverter operating in a fourth mode according to an embodiment of the present application;

[0027] Figure 7 is a schematic diagram of an internal circuit of a photovoltaic inverter according to an embodiment of the present application;

[0028] Figure 8 is a structural diagram of a control device for a photovoltaic inverter according to an embodiment of the present application;

[0029] Fig. 9 is a waveform diagram of multiple signals involved in the operation of a photovoltaic inverter according to an embodiment of the present application;

[0030] Fig.10 It is a hardware structure block diagram of a computer terminal for implementing a control method for a photovoltaic inverter according to an embodiment of the present application. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0032] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0033] In order to better understand the embodiments of the present application, the technical terms involved in the embodiments of the present application are explained as follows:

[0034] Phase: Used to describe the instantaneous angular position of a periodic signal.

[0035] In the related art, in order to enable the Buck type PWM inverter to be used in low voltage input scenarios, the Buck type PWM inverter is adjusted in the following ways: ① adding a Boost type DC conversion circuit in front of the inverter circuit in the Buck type PWM inverter to form a two-stage inverter circuit; ② connecting an industrial frequency transformer for boosting; ③ using a high frequency transformer to achieve electrical isolation and boost output; among them, method ① has the problem of limited reference scope due to small output capacity; method ② has the problem of increasing the volume, weight and cost of the circuit; method ③ has the problem of increasing the complexity, loss and cost of the circuit. In order to solve this problem, the relevant solution is provided in the embodiment of the present application, which is described in detail below.

[0036] According to an embodiment of the present application, a method embodiment of a control method for a photovoltaic inverter is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0037] Figure 1 is an internal circuit diagram of a photovoltaic inverter. The present application embodiment provides a control method for a photovoltaic inverter. The method is applied to a photovoltaic inverter having Figure 1 The photovoltaic inverter of the circuit structure shown in FIG. Figure 1 As shown, the photovoltaic inverter includes: a power supply E, a plurality of conversion circuits for converting input voltage, wherein the input voltage is the voltage output by the power supply E, and the plurality of conversion circuits share the following elements: the power supply E, a first inductor L1 connected to the power supply, a first power tube Q5 connected in parallel with the first inductor L1, and a second power tube Q6. The plurality of conversion circuits are used to convert the direct current output by the power supply E into alternating current, and then output it through the photovoltaic inverter; in addition, the plurality of conversion circuits can also supply energy to the energy storage element in the circuit, and the energy storage element includes: a capacitor cf and an inductor (L1, Lf) in the photovoltaic inverter; in addition, during the operation of the photovoltaic inverter, the inductor L1 (i.e., the first inductor) shared by the plurality of conversion circuits always remains in a conducting state.

[0038] Figure 2 is a flowchart of the steps of the photovoltaic inverter control method provided in the embodiment of the present application, such as Figure 2 As shown, the method comprises the following steps:

[0039] Step S202, determining a voltage cycle of the photovoltaic inverter operation, wherein the voltage cycle includes: a positive half cycle and a negative half cycle.

[0040] The method provided in the embodiment of the present application adjusts the AC voltage output by the photovoltaic inverter to the corresponding working mode by determining the voltage cycle of the AC voltage output by the photovoltaic inverter. Therefore, in step S202, before controlling the photovoltaic inverter to operate in a certain working mode, it is first determined in which voltage cycle the photovoltaic inverter is currently operating; since the voltage output by the photovoltaic inverter is a sinusoidal AC voltage, in the embodiment of the present application, the voltage cycle of the photovoltaic inverter operation includes: a positive half-cycle and a negative half-cycle.

[0041] Optionally, determining the voltage cycle of the photovoltaic inverter includes: determining the phase of a modulation signal, wherein the modulation signal is used to modulate the first power tube and the second power tube; when the phase is greater than 0, determining that the voltage cycle of the photovoltaic inverter is a positive half-cycle; when the phase is less than 0, determining that the voltage cycle of the photovoltaic inverter is a negative half-cycle.

[0042] In the embodiment of the present application, the photovoltaic inverter is used to convert the DC voltage output by the power source E into a sinusoidal AC voltage and then output it; in order to ensure the smooth output of the sinusoidal AC voltage, the embodiment of the present application adopts a sinusoidal pulse width modulation (SPWM) strategy to modulate the photovoltaic inverter; under the SPWM strategy, a carrier signal (u c ) and the modulation signal (u r ), where the modulation signal (u r ) is a sine wave reference signal with the same frequency and phase as the desired output AC signal. Voltage conversion is achieved by controlling the on and off elements of the conversion circuit (i.e., the first power tube Q5 and the second power tube Q6 in the embodiment of the present application). By controlling the high-speed on and off of Q5 and Q6, the charge and discharge cycle of the inductor L1 and the capacitor Cf can be controlled, and thus the output voltage of the photovoltaic inverter can be controlled. Therefore, the modulation signal (u r ) continuously modulates the first power tube Q5 and the second power tube Q6, so that the photovoltaic inverter can output a sinusoidal AC voltage; due to the modulation signal (u r ) is a sine wave reference signal with the same frequency and phase as the desired output AC signal (i.e., sinusoidal AC voltage). The waveforms of the two are similar. Therefore, the modulation signal (u r ) determines which voltage cycle the photovoltaic inverter is currently operating in. Specifically, the modulation signal (u r) is a sine wave with a complete cycle. When the phase is used to represent the cycle, a complete cycle can be expressed as 0 to 360 degrees in the angle system, or as 0 radians to 2π radians in the radian system. When the phase angle is between 0 and 180 degrees (or 0 radians to π radians), the signal value is positive. In a sine wave, this means that the signal rises from its zero point to its peak value and then drops to zero. At this time, the instantaneous value of the signal is greater than 0. When the phase angle of an AC signal is between 180 and 360 degrees (or from π radians to To 2π radians), the signal value is negative. In a sine wave, this means that the signal starts to drop from zero to its negative peak value and then rises to zero. At this time, the instantaneous value of the signal is less than 0. In one cycle, 0 degrees (or 0 radians) and 180 degrees (or π radians) are the positions of the signal zero crossing points, where the signal changes from positive to negative or from negative to positive. Therefore, by comparing the phase of the signal with 0 degrees (or the modulus of 2π), it can be determined which half of the cycle the signal is in. In this embodiment, the modulation signal (u r ) and 0 degrees, when the modulation signal (u r ) is greater than 0 degrees, it is determined that the photovoltaic inverter is operating in the positive half cycle. r ) is less than 0 degrees, it is determined that the photovoltaic inverter is operating in the negative half cycle; if the obtained modulation signal (u r ) is expressed in radians, and we want to convert it to the corresponding angle and compare it with 0 degrees. r ) is equal to 0 when the sine wave changes from positive to negative or from negative to positive. r ) will not be continuously equal to 0, and will not affect the voltage cycle of the photovoltaic inverter. Therefore, there is no need to consider the modulation signal (u r ) is equal to 0. In addition, since the waveform of the sine wave is distributed up and down around the axis representing the zero level, the period represented by the waveform above the axis (the axis representing the zero level) is the positive half period, and the period represented by the waveform below the axis (the axis representing the zero level) is the negative half period, in the embodiment of the present application, it is also possible to determine the modulation signal (u r )’s waveform relative to the axis representing the zero level to determine the voltage cycle of the PV inverter operation.

[0043] According to some optional embodiments of the present application, the photovoltaic inverter also includes: a filter circuit, wherein the filter circuit is connected to the first conversion circuit through a third power tube in the photovoltaic inverter, and the filter circuit is connected to the second conversion circuit through a fourth power tube in the photovoltaic inverter.

[0044] like Figure 1As shown, the photovoltaic inverter provided in the embodiment of the present application also includes a filter circuit composed of a capacitor Cf, a resistor RL and an inductor Lf (i.e., a second inductor), and the filter circuit is used to filter out the high-frequency switching noise and ripple generated during the inversion process, thereby outputting a stable AC power supply. The filter circuit composed of a capacitor Cf, a resistor RL and an inductor Lf (i.e., a second inductor) is connected to the conversion circuit of the photovoltaic inverter through power tubes included in different conversion circuits, specifically, as Figure 1 As shown, the filter circuit is connected to different conversion circuits of the photovoltaic inverter through power tube Q3 (i.e., the third power tube) and power tube Q4 (i.e., the fourth power tube), respectively. In this embodiment, power tube Q3 (i.e., the third power tube) works in the positive half cycle and belongs to the conversion circuit (i.e., the first conversion circuit) that operates in the positive half cycle. Therefore, the filter circuit is connected to the positive half cycle conversion circuit (i.e., the first conversion circuit) through power tube Q3; power tube Q4 (i.e., the fourth power tube) works in the negative half cycle and belongs to the conversion circuit (i.e., the second conversion circuit) that operates in the negative half cycle. Therefore, the filter circuit is connected to the negative half cycle conversion circuit (i.e., the second conversion circuit) through power tube Q4. In addition, as Figure 1 As shown, when the above three components form a filter circuit, they are connected in series to form a closed filter circuit using the following method: one end of the capacitor Cf is connected to one end of the inductor Lf, the other end of the capacitor Cf is connected to one end of the load (i.e., the resistor RL), and one end of the inductor Lf is connected to the other end of the load (i.e., the resistor RL). Among them, the capacitor Cf can be an AC ceramic capacitor, or a film capacitor, aluminum electrolytic capacitor, or other types of capacitors that meet the loss requirements, capacity requirements, and frequency response requirements.

[0045] Step S204, when the photovoltaic inverter operates in the positive half cycle, the photovoltaic inverter is controlled to operate a first conversion circuit among multiple conversion circuits, and the photovoltaic inverter is controlled to operate in a first type of mode corresponding to the positive half cycle; when the photovoltaic inverter operates in the negative half cycle, the photovoltaic inverter is controlled to operate a second conversion circuit among multiple conversion circuits, and the photovoltaic inverter is controlled to operate in a second type of mode corresponding to the negative half cycle, wherein when the photovoltaic inverter operates in different modes, the semiconductor devices in the photovoltaic inverter that are in a conductive state are different.

[0046] After determining the voltage cycle of the photovoltaic inverter in step S202, the corresponding mode is set for it in step S204. In the embodiment of the present application, if the voltage cycle is a positive half-cycle, the photovoltaic inverter turns on one of the multiple conversion circuits it contains (i.e., the first conversion circuit), and controls the elements in the first conversion circuit to be in an on state or an off state so that the photovoltaic inverter operates in a working mode corresponding to the positive half-cycle (i.e., the first type of mode); if the voltage cycle is a negative half-cycle, the photovoltaic inverter turns on another conversion circuit (i.e., the second conversion circuit) that is different from the circuit (i.e., the first conversion circuit) that is turned on in the positive half-cycle, and controls the elements in the second conversion circuit to be in an on state or an off state so that the photovoltaic inverter operates in a working mode corresponding to the negative half-cycle (i.e., the second type of mode). In the embodiments of the present application, the working mode in which the photovoltaic inverter works in the positive half-cycle and the working mode in which the photovoltaic inverter works in the negative half-cycle can be pre-defined in the control algorithm. Therefore, in other optional embodiments, it can also be pre-defined that the photovoltaic inverter turns on the second conversion circuit in the positive half-cycle and works in the second type of working mode. At this time, the photovoltaic inverter turns on the first conversion circuit in the negative half-cycle and works in the first type of working mode; it is sufficient to ensure that the photovoltaic inverter turns on different boost circuits (i.e., conversion circuits) in different voltage cycles. From the above, it can be seen that the conversion circuit (i.e., the first conversion circuit) that is turned on when the photovoltaic inverter is running in the positive half-cycle is different from the conversion circuit (i.e., the second conversion circuit) that is turned on when the photovoltaic inverter is running in the negative half-cycle. In the embodiment of the present application, the circuit is switched by controlling the operating state (on or off) of the power tube. In addition, the direction of current flow will affect the operating state (on or off) of the diode in the photovoltaic inverter. Therefore, when these two circuits (i.e., the first conversion circuit and the second conversion circuit) are each in the on state, the state of the on semiconductor devices (including the power tube and the diode) is not exactly the same.

[0047] Optionally, the first conversion circuit includes: a power supply, a first inductor, multiple semiconductor devices, and a filter circuit, wherein the multiple semiconductor devices include: a first diode, multiple power tubes, and the multiple power tubes include: a first power tube, a second power tube, a third power tube, and a fifth power tube, wherein the first power tube is connected to the first inductor and the third power tube, the second power tube is connected to the collector of the first inductor and the fifth power tube, the fifth power tube is connected to the second power tube and the negative electrode of the power supply, and the two ends of the first diode are respectively connected to the second power tube and the filter circuit.

[0048] In the embodiment of the present application, when the photovoltaic inverter operates in the positive half cycle, the positive half cycle conversion circuit (i.e., the first conversion circuit) is controlled to be in the on state; in the present embodiment, the positive half cycle conversion circuit is a closed circuit composed of a power source E and a first inductor L1 shared with the negative half cycle conversion circuit, a plurality of semiconductor devices included in the photovoltaic inverter, and a plurality of components included in the filter circuit in the previous embodiment; specifically, Figure 1 In the photovoltaic inverter shown in FIG. 1 , a photovoltaic power source E, an inductor L1, a power tube Q2 (i.e., a fifth power tube), a power tube Q3 (i.e., a third power tube), a power tube Q5 (i.e., a first power tube), a power tube Q6 (i.e., a second power tube), a capacitor Cf, and a diode D4 (i.e., a first diode) are used to form a Boost circuit that works in a positive half-cycle. Next, in combination with Figure 1 Describe the connection relationship of each component included in the positive half-cycle conversion circuit (i.e., the first conversion circuit), such as Figure 1 As shown, the positive electrode of the power supply E is connected to one end of the inductor L1, and the other end of the inductor L1 is respectively connected to the collector of the power tube Q5 (i.e., the first power tube) and the collector of the power tube Q6 (i.e., the second power tube), the emitter of the power tube Q5 (i.e., the first power tube) is connected to the collector of the power tube Q3 (i.e., the third power tube), the emitter of the power tube Q3 (i.e., the third power tube) is connected to one end of the filter circuit, the emitter of the power tube Q6 (i.e., the second power tube) is respectively connected to the collector of the power tube Q2 (i.e., the fifth power tube) and the cathode of the diode D4 (i.e., the first diode), and the emitter of the power tube Q2 (i.e., the fifth power tube) is connected to the negative electrode of the power supply E. Through the above connection method, a closed loop is formed.

[0049] According to some optional embodiments of the present application, the first type of mode includes: a first mode and a second mode, wherein, when the photovoltaic inverter operates in the first mode and the second mode, the number of current loops is different; controlling the photovoltaic inverter to operate in the first type of mode corresponding to the positive half-cycle includes: determining a first instantaneous value of a carrier signal and a second instantaneous value of a modulation signal, wherein the carrier signal is used to control the output of the photovoltaic inverter, and the modulation signal is used to modulate the first power tube and the second power tube; when the first instantaneous value is greater than the second instantaneous value, controlling the photovoltaic inverter to operate in the first mode; when the first instantaneous value is less than the second instantaneous value, controlling the photovoltaic inverter to operate in the second mode.

[0050] In this embodiment, when the photovoltaic inverter realizes voltage conversion through the positive half-cycle conversion circuit (i.e., the first conversion circuit), the positive half-cycle conversion circuit is controlled to operate in a preset positive half-cycle working mode (i.e., the first type of working mode), wherein the first type of working mode is divided into two different working modes (i.e., the first mode and the second mode) according to the different conduction elements, and when the first conversion circuit is turned on and operated in different modes, the number of current loops it contains is different. In this embodiment, according to the carrier signal (u c ) and the modulation signal (u r ) is compared with the instantaneous value of the first conversion circuit to determine the working mode of the first conversion circuit in the positive half cycle. Specifically, when the carrier signal (u c ) is greater than the modulation signal (u r ) (i.e., the second instantaneous value), the first conversion circuit is controlled to conduct in the positive half-cycle multi-current loop mode (i.e., the first mode). When the carrier signal (u c ) is smaller than the instantaneous value of the modulation signal (u r ) (i.e., the second instantaneous value), the first conversion circuit is controlled to conduct in the mode of the positive half-cycle less current loop (i.e., the second mode). c ) is the signal used to control the output of the photovoltaic inverter when the photovoltaic inverter is modulated using the SPWM strategy. The modulation signal (u r ) is a signal used to modulate the elements (in the embodiment of the present application, the first power tube Q5 and the second power tube Q6) that control the on and off of the conversion circuit.

[0051] Optionally, controlling the photovoltaic inverter to operate in a first mode includes: controlling the states of all power tubes in the first conversion circuit to be on, and controlling the states of other power tubes of the first type to be off, wherein the other power tubes of the first type are power tubes that do not belong to the first conversion circuit among all power tubes contained in the photovoltaic inverter; controlling the photovoltaic inverter to operate in a second mode includes: controlling the state of the second power tube to be off, controlling the state of other power tubes of the second type to be on, and controlling the state of other power tubes of the first type to be off, wherein the other power tubes of the second type are power tubes in the first conversion circuit other than the second power tube.

[0052] As mentioned in the above embodiments, the positive half-cycle working mode (i.e., the first type of working mode) corresponding to the positive half-cycle conversion circuit (i.e., the first conversion circuit) is two different working modes. In the embodiments of the present application, the working mode of the first conversion circuit is adjusted by controlling the operating state (on and off) of multiple components in the photovoltaic inverter. For example, in the present embodiment, if the first conversion circuit is to be controlled to be turned on and operated in the mode of the positive half-cycle multi-current loop (i.e., the first mode), all power tubes constituting the first conversion circuit are controlled to remain in the on state, and the power tubes that do not belong to the first conversion circuit (i.e., the first type of other power tubes) are controlled to remain in the off state. At this time, the photovoltaic inverter operates in the first mode. Figure 3 This is the circuit diagram of the photovoltaic inverter when it operates in the first mode. Figure 3 The middle dotted line indicates that the current cannot be conducted. Figure 3 As shown, when the photovoltaic inverter works in the first mode mentioned above, the photovoltaic power source E, inductor L1, power tube Q6, and power tube Q2 are in the on state, forming a power loop I; the photovoltaic power source E, inductor L1, power tube Q5, power tube Q3, capacitor Cf, inductor Lf, diode D4, power tube Q2, and load RL are in the on state, forming a current loop II. In loop I, the photovoltaic power source E charges the inductor L1, and the current of the inductor L1 increases linearly; in loop II, the photovoltaic power source E supplies power to the capacitor Cf and the load RL. At the end of the power supply, the power tube Q3 is subjected to the reverse voltage and is turned off, and the capacitor Cf continues to discharge the load RL. At this time, the voltage U across the capacitor Cf is Cf =U E -U L1 , where U E is the voltage across the power source E, U L1 is the voltage across the inductor L1. To control the first conversion circuit to operate in the mode of the positive half-cycle less current loop (i.e., the second mode), the power tube Q6 (i.e., the second power tube) constituting the first conversion circuit is controlled to be disconnected, the remaining power tubes (i.e., the second type of other power tubes) in the first conversion circuit are turned on, and the power tubes that do not belong to the first conversion circuit (i.e., the first type of other power tubes) are controlled to remain disconnected. At this time, the photovoltaic inverter operates in the second mode; Figure 4 This is the circuit diagram of the photovoltaic inverter when it operates in the second mode. Figure 4 The middle dotted line indicates that the current cannot be conducted. Figure 4 As shown, when the photovoltaic inverter works in the second mode, the power tubes Q2, Q3 and Q5 are turned on, and the power tubes Q1, Q4 and Q6 are turned off (disconnected); the photovoltaic power source E, the inductor L1, the power tube Q5, the power tube Q3, the capacitor Cf, the diode D4 and the power tube Q2 form a loop I. In the loop I, the photovoltaic power source E and the inductor L1 jointly supply power to the capacitor Cf and the load RL, and the current of the inductor L1 decreases linearly. At this time, the voltage U across the capacitor Cf isCf =U E +U L1 .

[0053] According to some other optional embodiments of the present application, the second conversion circuit includes: a power supply, a first inductor, multiple semiconductor devices, and a filter circuit, wherein the multiple semiconductor devices include: a second diode, multiple power tubes, wherein the multiple power tubes include: a first power tube, a second power tube, a fourth power tube and a sixth power tube, wherein the first power tube and the second power tube are connected in parallel with the first inductor, the fourth power tube is connected to the second power tube and the filter circuit, the sixth power tube is connected to the first power tube and the negative electrode of the power supply, and the two ends of the second diode are respectively connected to the first power tube and the filter circuit.

[0054] In the embodiment of the present application, when the photovoltaic inverter operates in the negative half cycle, the negative half cycle conversion circuit (i.e., the second conversion circuit) is controlled to be in the on state; in the present embodiment, the negative half cycle conversion circuit is a closed circuit composed of a power source E and a first inductor L1 shared with the positive half cycle conversion circuit, a plurality of semiconductor devices included in the photovoltaic inverter, and a plurality of components included in the filter circuit mentioned in the above embodiment; specifically, Figure 1 In the photovoltaic inverter shown in FIG. 1 , a photovoltaic power source E, an inductor L1, a power tube Q1 (i.e., the sixth power tube), a power tube Q4 (i.e., the fourth power tube), a power tube Q5 (i.e., the first power tube), a power tube Q6 (i.e., the second power tube), a capacitor Cf, and a diode D3 (i.e., the second diode) form a Boost circuit that works in a negative half-cycle. Next, in combination with Figure 1 Describe the connection relationship of each component included in the negative half-cycle conversion circuit (i.e., the second conversion circuit), such as Figure 1 As shown, the positive electrode of the power supply E is connected to one end of the inductor L1, and the other end of the inductor L1 is respectively connected to the collector of the power tube Q5 (i.e., the first power tube) and the collector of the power tube Q6 (i.e., the second power tube), the emitter of the power tube Q5 (i.e., the first power tube) is connected to the collector of the power tube Q1 (i.e., the sixth power tube), the emitter of the power tube Q1 (i.e., the sixth power tube) is connected to the negative electrode of the power supply E, the emitter of the power tube Q6 (i.e., the second power tube) is connected to the collector of the power tube Q4 (i.e., the fourth power tube), and the emitter of the power tube Q4 (i.e., the fourth power tube) is connected to the filter circuit. Through the above connection method, a closed loop is formed.

[0055] Optionally, the second mode includes: a third mode and a fourth mode, wherein the number of current loops is different when the photovoltaic inverter operates in the third mode and the fourth mode; controlling the photovoltaic inverter to operate in the second mode corresponding to the negative half-cycle includes: determining a first instantaneous value of a carrier signal and a second instantaneous value of a modulation signal, wherein the carrier signal is used to control the output of the photovoltaic inverter, and the modulation signal is used to modulate the first power tube and the second power tube; when the first instantaneous value is greater than the second instantaneous value, controlling the photovoltaic inverter to operate in the third mode; when the first instantaneous value is less than the second instantaneous value, controlling the photovoltaic inverter to operate in the fourth mode.

[0056] In this embodiment, when the photovoltaic inverter realizes voltage conversion through the negative half-cycle conversion circuit (i.e., the second conversion circuit), the negative half-cycle conversion circuit is controlled to operate in a preset negative half-cycle working mode (i.e., the second type of working mode), wherein the second type of working mode is divided into two different working modes (i.e., the third mode and the fourth mode) according to the different conduction elements, and when the second conversion circuit is turned on and operated in different modes, the number of current loops it contains is different. In this embodiment, since the SPWM strategy is adopted to modulate the photovoltaic inverter, the carrier signal (u c ) and the modulation signal (u r ) is the signal used to control the photovoltaic inverter under the SPWM strategy, where the carrier signal (u c ) is used to control the output of the photovoltaic inverter, the modulation signal (u r ) is used to modulate the on and off components of the control conversion circuit; therefore, the same method can be used to determine the working mode of the photovoltaic inverter in the negative half cycle; for example, referring to the above method for determining the working mode of the positive half cycle, according to the carrier signal (u c ) and the modulation signal (u r ) is compared with the instantaneous value of the second conversion circuit to determine the working mode of the second conversion circuit in the negative half cycle. Specifically, when the carrier signal (u c ) is greater than the modulation signal (u r ) (i.e., the second instantaneous value), the second conversion circuit is controlled to conduct in the mode of the negative half-cycle multi-current loop (i.e., the third mode). When the carrier signal (u c ) is smaller than the instantaneous value of the modulation signal (u r ), the second conversion circuit is controlled to conduct and operate in a mode with a negative half-cycle less current loop (ie, the fourth mode).

[0057] According to some other optional embodiments of the present application, controlling the photovoltaic inverter to operate in a third mode includes: controlling the state of all power tubes in the second conversion circuit to be on, and controlling the state of other power tubes of the third category to be off, wherein the other power tubes of the third category are power tubes that do not belong to the second conversion circuit among all power tubes included in the photovoltaic inverter; controlling the photovoltaic inverter to operate in a fourth mode includes: controlling the state of the first power tube to be off, controlling the state of other power tubes of the fourth category to be on, and controlling the state of other power tubes of the third category to be off, wherein the other power tubes of the fourth category are power tubes in the second conversion circuit other than the first power tube.

[0058] As mentioned in the above embodiment, the negative half-cycle working mode (i.e., the second type of working mode) corresponding to the negative half-cycle conversion circuit (i.e., the second conversion circuit) is two different working modes. In the embodiment of the present application, the working mode of the second conversion circuit is still adjusted by controlling the operating state (on and off) of multiple components in the photovoltaic inverter; for example, in the present embodiment, if the second conversion circuit is to be controlled to be turned on and operated in the mode of the negative half-cycle multi-current loop (i.e., the third mode), all power tubes constituting the second conversion circuit are controlled to remain in the on state, and the power tubes that do not belong to the second conversion circuit (i.e., the other power tubes of the third type) are controlled to remain in the off state. At this time, the photovoltaic inverter operates in the third mode. Figure 5 This is the circuit diagram of the photovoltaic inverter when it operates in the third mode. Figure 5 The middle dotted line indicates that the current cannot be conducted. Figure 5 As shown, when the photovoltaic inverter works in the third mode mentioned above, the power tubes Q1, Q4, Q5 and Q6 are turned on, and the power tubes Q2 and Q3 are turned off; the photovoltaic power source E, the inductor L1, the power tube Q5 and Q1 form loop I; the photovoltaic power source E, the inductor L1, the power tube Q6, the power tube Q4, the capacitor Cf, the inductor Lf, the diode D3, the power tube Q1 and the load RL form loop II. In loop I, the photovoltaic power source E charges the inductor L1, and the current of the inductor L1 increases linearly; in loop II, the photovoltaic power source E supplies power to the capacitor Cf and the load RL. At the end of the power supply, the power tube Q3 is subjected to the reverse voltage and is turned off, and the capacitor Cf continues to discharge the load RL. At this time, the voltage U across the capacitor Cf is Cf =U E -U L1 Among them, U E is the voltage across the power source E, U L1is the voltage across the inductor L1. To control the second conversion circuit to operate in the mode of the negative half-cycle less current loop (i.e., the fourth mode), the power tube Q5 (i.e., the first power tube) constituting the second conversion circuit is controlled to be disconnected, the remaining power tubes (i.e., the fourth type of other power tubes) in the second conversion circuit are turned on, and the power tubes that do not belong to the second conversion circuit (i.e., the third type of other power tubes) are controlled to remain disconnected. At this time, the photovoltaic inverter operates in the fourth mode; Figure 6 This is the circuit diagram of the photovoltaic inverter when it operates in the fourth mode. Figure 6 The middle dotted line indicates that the current cannot be conducted. Figure 6 As shown, when the photovoltaic inverter works in the fourth mode mentioned above, the power tubes Q1, Q4 and Q6 are turned on, and the power tubes Q2, Q3 and Q5 are turned off (disconnected); the photovoltaic power source E, the inductor L1, the power tube Q6, the power tube Q4, the capacitor Cf, the diode D3 and the power tube Q1 form a loop I. In the loop I, the photovoltaic power source E and the inductor L1 jointly supply power to the capacitor Cf and the load RL, and the current of the inductor L1 decreases linearly. At this time, the voltage U across the capacitor Cf Cf =U E +U L1 .

[0059] Through the above steps, the output of positive and negative half-cycle AC power is achieved by using a shared Boost circuit energy storage inductor, so that the photovoltaic inverter can be directly used in low-voltage input scenarios. Compared with the same type of inverters, the number of diodes is reduced, and the temperature rise during the application of the photovoltaic inverter is reduced; by adjusting the working mode under different voltage cycles, the power conversion efficiency of the inverter can be improved and the technical effect of reducing energy loss can be achieved.

[0060] Figure 7 is a schematic diagram of the internal circuit of a photovoltaic inverter provided according to an embodiment of the present application, such as Figure 7 As shown, the photovoltaic inverter includes: a power supply E, a plurality of conversion circuits for converting an input voltage, and a filter circuit, wherein the input voltage is the voltage output by the power supply E; the plurality of conversion circuits share the following elements: a power supply E, a first inductor L1 connected to the power supply, a first power tube Q5 and a second power tube Q6 connected in parallel with the first inductor, wherein the first inductor L1 remains in a conducting state during the operation of the photovoltaic inverter; and the filter circuit is connected to the plurality of conversion circuits through the third power tube Q3 and the fourth power tube Q4 in the photovoltaic inverter, respectively.

[0061] like Figure 7As shown, the filter circuit is composed of a capacitor Cf, a resistor RL and an inductor Lf (i.e., the second inductor), wherein one end of the capacitor Cf is connected to one end of the inductor Lf, the other end of the capacitor Cf is connected to one end of the load (i.e., the resistor RL), and one end of the inductor Lf is connected to the other end of the load (i.e., the resistor RL). In this embodiment, the filter circuit is connected to different conversion circuits of the photovoltaic inverter through the power tube Q3 (i.e., the third power tube) and the power tube Q4 (i.e., the fourth power tube). Since in this embodiment, the power tube Q3 (i.e., the third power tube) works in the positive half cycle and belongs to the conversion circuit (i.e., the first conversion circuit) that operates in the positive half cycle, the filter circuit is connected to the positive half cycle conversion circuit (i.e., the first conversion circuit) through the power tube Q3; the power tube Q4 (i.e., the fourth power tube) works in the negative half cycle and belongs to the conversion circuit (i.e., the second conversion circuit) that operates in the negative half cycle, therefore, the filter circuit is connected to the negative half cycle conversion circuit (i.e., the second conversion circuit) through the power tube Q4. The first conversion circuit is a circuit that is turned on and operated in the positive half cycle of the photovoltaic inverter, such as Figure 7 As shown, the first conversion circuit is composed of a photovoltaic power source E, an inductor L1, a power tube Q2 (i.e., the fifth power tube), a power tube Q3 (i.e., the third power tube), a power tube Q5 (i.e., the first power tube), a power tube Q6 (i.e., the second power tube), a capacitor Cf, and a diode D4 (i.e., the first diode). The second conversion circuit is a circuit that is turned on and operated in the negative half cycle of the photovoltaic inverter, such as Figure 7 As shown, the second conversion circuit is composed of a photovoltaic power source E, an inductor L1, a power tube Q1 (i.e., the sixth power tube), a power tube Q4 (i.e., the fourth power tube), a power tube Q5 (i.e., the first power tube), a power tube Q6 (i.e., the second power tube), a capacitor Cf, and a diode D3 (i.e., the second diode).

[0062] Figure 8 is a structural diagram of a photovoltaic inverter control device provided according to an embodiment of the present application, the device is applied to a photovoltaic inverter (for example, it can be applied to Figure 7The photovoltaic inverter shown in the figure) comprises: a power supply, a plurality of conversion circuits for converting an input voltage, wherein the input voltage is a voltage output by the power supply, and the plurality of conversion circuits share the following elements: a power supply, a first inductor connected to the power supply, a first power tube and a second power tube connected in parallel with the first inductor; the control device of the photovoltaic inverter comprises: a determination module 80, for determining a voltage cycle of the photovoltaic inverter operation, wherein the voltage cycle comprises: a positive half cycle and a negative half cycle; a control module 82, for controlling the photovoltaic inverter to operate a first conversion circuit among the plurality of conversion circuits when the photovoltaic inverter operates in a positive half cycle, and to control the photovoltaic inverter to operate in a first type of mode corresponding to the positive half cycle, and for controlling the photovoltaic inverter to operate a second conversion circuit among the plurality of conversion circuits when the photovoltaic inverter operates in a negative half cycle, and to control the photovoltaic inverter to operate in a second type of mode corresponding to the negative half cycle, wherein when the photovoltaic inverter operates in different modes, the semiconductor devices in the photovoltaic inverter that are in a conductive state are different.

[0063] It should be noted that Figure 8 The preferred implementation of the illustrated embodiment can be found in Figure 2 The relevant description of the illustrated embodiment will not be repeated here.

[0064] The control device of photovoltaic inverter is applied in Figure 7 When the photovoltaic inverter device shown in the figure is used, the determination module 80 is first used to determine whether the photovoltaic inverter is currently operating in the positive half cycle of the output voltage or in the negative half cycle of the output voltage. Further, the control module 82 is used to control the photovoltaic inverter to operate in a mode corresponding to the voltage cycle. In this embodiment, the control device of the photovoltaic inverter modulates the photovoltaic inverter through the SPWM modulation strategy. Under the SPWM modulation strategy, the power tube conduction duty cycle is set to d(t), and the voltage u across the load RL is set to o (t) = U m sin(ωt), where sin represents the sine function, ω represents the angular frequency of the AC voltage, and U m represents the peak value of the voltage output by the photovoltaic inverter. Since the photovoltaic inverter provided in the embodiment of the present application is composed of two identical Boost circuits (i.e., conversion circuits), the output voltage of the inverter is Therefore, the power tube conduction duty cycle is d(t) and can also be expressed as Fig. 9 It is a waveform diagram of multiple signals involved in the operation of the photovoltaic inverter, such as Fig. 9 As shown, when the control module 82 adopts the SPWM modulation strategy to modulate the photovoltaic inverter, the carrier signal (u c ) is a triangular wave signal, which is used to modulate the power tubes Q5 and Q6. r) and the expected output AC voltage (u o ) have the same waveform, both are sine wave signals; by modulating the signal (u r ) controls the operating status (on and off) of power tubes Q5 and Q6 in the positive and negative half cycles, and controls the operating status (on and off) of other power tubes (Q1, Q2, Q3 and Q4) in the positive and negative half cycles through other signals. The photovoltaic inverter adopts different working modes in the positive and negative half cycles to realize voltage conversion.

[0065] The method embodiments provided in the embodiments of the present application may be executed in a mobile terminal, a computer terminal or a similar computing device; for example, the method may be output in a mobile terminal, a computer terminal or a similar computing device. Fig. 9 Signals with different waveforms are shown. Fig.10 FIG. 1 shows a hardware structure block diagram of a computer terminal for implementing a control method for a photovoltaic inverter. Fig.10 As shown, the computer terminal 10 may include one or more (102a, 102b, ..., 102n are used to illustrate) processors 102 (the processor 102 may include but is not limited to a processing device such as a microprocessor MCU or a programmable logic device FPGA), a memory 104 for storing data, and a transmission device 106 for communication functions. In addition, it may also include: a display, an input / output interface (I / O interface), a universal serial bus (USB) port (which may be included as one of the ports of the BUS bus), a network interface, a power supply and / or a camera. It can be understood by those skilled in the art that Fig.10 The structure shown is only for illustration and does not limit the structure of the above electronic device. Fig.10 More or fewer components as shown, or with Fig.10 Different configurations shown.

[0066] It should be noted that the one or more processors 102 and / or other data processing circuits described above may generally be referred to herein as "data processing circuits". The data processing circuits may be embodied in whole or in part as software, hardware, firmware, or any other combination thereof. In addition, the data processing circuit may be a single independent processing module, or may be incorporated in whole or in part into any of the other components in the computer terminal 10. As described in the embodiments of the present application, the data processing circuit acts as a processor control (e.g., selection of a variable resistor terminal path connected to an interface).

[0067] The memory 104 can be used to store software programs and modules of application software, such as the program instructions / data storage device corresponding to the control method of the photovoltaic inverter in the embodiment of the present application. The processor 102 executes various functional applications and data processing by running the software programs and modules stored in the memory 104, that is, the control method of the photovoltaic inverter described above is realized. The memory 104 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 104 may further include a memory remotely arranged relative to the processor 102, and these remote memories may be connected to the computer terminal 10 via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0068] The transmission device 106 is used to receive or send data via a network. The specific example of the above network may include a wireless network provided by a communication provider of the computer terminal 10. In one example, the transmission device 106 includes a network adapter (Network Interface Controller, NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 106 can be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0069] The display may be, for example, a touch screen liquid crystal display (LCD) that enables a user to interact with a user interface of the computer terminal 10 .

[0070] An embodiment of the present application further provides a non-volatile storage medium, in which a computer program is stored, wherein the above photovoltaic inverter control method is executed by running the computer program on a device where the non-volatile storage medium is located.

[0071] The above-mentioned non-volatile storage medium is used to store a program that performs the following functions: determining a voltage cycle of the operation of the photovoltaic inverter, wherein the voltage cycle includes: a positive half-cycle and a negative half-cycle; when the photovoltaic inverter operates in the positive half-cycle, controlling the photovoltaic inverter to operate a first conversion circuit among multiple conversion circuits, and controlling the photovoltaic inverter to operate in a first type of mode corresponding to the positive half-cycle; when the photovoltaic inverter operates in the negative half-cycle, controlling the photovoltaic inverter to operate a second conversion circuit among multiple conversion circuits, and controlling the photovoltaic inverter to operate in a second type of mode corresponding to the negative half-cycle, wherein when the photovoltaic inverter operates in different modes, the semiconductor devices in the photovoltaic inverter that are in a conductive state are different.

[0072] An embodiment of the present application further provides an electronic device, including a memory and a processor, wherein a computer program is stored in the memory, and the processor is configured to execute the above photovoltaic inverter control method through the computer program.

[0073] The processor in the above-mentioned electronic device is used to run a program that performs the following functions: determine the voltage cycle of the photovoltaic inverter, wherein the voltage cycle includes: a positive half-cycle and a negative half-cycle; when the photovoltaic inverter operates in the positive half-cycle, control the photovoltaic inverter to operate a first conversion circuit among multiple conversion circuits, and control the photovoltaic inverter to operate in a first type of mode corresponding to the positive half-cycle; when the photovoltaic inverter operates in the negative half-cycle, control the photovoltaic inverter to operate a second conversion circuit among multiple conversion circuits, and control the photovoltaic inverter to operate in a second type of mode corresponding to the negative half-cycle, wherein when the photovoltaic inverter operates in different modes, the semiconductor devices in the photovoltaic inverter that are in a conductive state are different.

[0074] The embodiment of the present application further provides a computer program product, including computer instructions, which implement the steps of the above photovoltaic inverter control method when executed by a processor.

[0075] It should be noted that the various modules in the control device of the above-mentioned photovoltaic inverter can be program modules (for example, a set of program instructions for implementing a certain specific function) or hardware modules. For the latter, it can be expressed in the following forms, but is not limited to this: the expression form of each of the above-mentioned modules is a processor, or the functions of each of the above-mentioned modules are implemented by a processor.

[0076] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0077] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0078] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0079] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0080] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0081] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the relevant technology or all or part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, disk or optical disk, etc. Various media that can store program codes.

[0082] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A control method for a photovoltaic inverter, characterized in that: Applied to a photovoltaic inverter, wherein the photovoltaic inverter comprises: a power supply, a plurality of conversion circuits for converting an input voltage, wherein the input voltage is a voltage output by the power supply, and the plurality of conversion circuits share the following elements: the power supply, a first inductor connected to the power supply, a first power tube and a second power tube connected in parallel to the first inductor; The method comprises: Determine a voltage cycle of the photovoltaic inverter operation, wherein the voltage cycle includes: a positive half cycle and a negative half cycle; When the photovoltaic inverter operates in the positive half cycle, the photovoltaic inverter is controlled to operate the first conversion circuit among the multiple conversion circuits, and the photovoltaic inverter is controlled to operate in the first type of mode corresponding to the positive half cycle. When the photovoltaic inverter operates in the negative half cycle, the photovoltaic inverter is controlled to operate the second conversion circuit among the multiple conversion circuits, and the photovoltaic inverter is controlled to operate in the second type of mode corresponding to the negative half cycle, wherein when the photovoltaic inverter operates in different modes, the semiconductor devices in the photovoltaic inverter that are in a conductive state are different.

2. The method according to claim 1, characterized in that The photovoltaic inverter further includes: a filter circuit, wherein the filter circuit is connected to the first conversion circuit via a third power tube in the photovoltaic inverter, and the filter circuit is connected to the second conversion circuit via a fourth power tube in the photovoltaic inverter.

3. The method according to claim 2, characterized in that The first conversion circuit includes: the power supply, the first inductor, a plurality of semiconductor devices, the filter circuit, wherein: The multiple semiconductor devices include: a first diode, and multiple power tubes, and the multiple power tubes include: the first power tube, the second power tube, the third power tube and the fifth power tube, wherein the first power tube is connected to the first inductor and the third power tube, the second power tube is connected to the first inductor and the collector of the fifth power tube, the fifth power tube is connected to the second power tube and the negative electrode of the power supply, and the two ends of the first diode are respectively connected to the second power tube and the filter circuit.

4. The method according to claim 3, characterized in that The first mode includes: a first mode and a second mode, wherein when the photovoltaic inverter operates in the first mode and the second mode, the number of current loops is different; controlling the photovoltaic inverter to operate in the first mode corresponding to the positive half cycle includes: Determine a first instantaneous value of a carrier signal and a second instantaneous value of a modulation signal, wherein the carrier signal is used to control the output of the photovoltaic inverter, and the modulation signal is used to modulate the first power tube and the second power tube; When the first instantaneous value is greater than the second instantaneous value, controlling the photovoltaic inverter to operate in the first mode; When the first instantaneous value is less than the second instantaneous value, the photovoltaic inverter is controlled to operate in the second mode.

5. The method according to claim 4, characterized in that Controlling the photovoltaic inverter to operate in the first mode includes: controlling the states of all power tubes in the first conversion circuit to be turned on, and controlling the states of other power tubes of the first type to be turned off, wherein the other power tubes of the first type are power tubes that do not belong to the first conversion circuit among all power tubes included in the photovoltaic inverter; Controlling the photovoltaic inverter to operate in the second mode includes: controlling the state of the second power tube to be disconnected, controlling the state of other power tubes of the second type to be turned on, and controlling the state of other power tubes of the first type to be disconnected, wherein the other power tubes of the second type are power tubes in the first conversion circuit other than the second power tube.

6. The method according to claim 2, characterized in that The second conversion circuit includes: the power supply, the first inductor, a plurality of semiconductor devices, the filter circuit, wherein: The multiple semiconductor devices include: a second diode, and multiple power tubes, wherein the multiple power tubes include: the first power tube, the second power tube, the fourth power tube and the sixth power tube, wherein the first power tube and the second power tube are connected in parallel with the first inductor, the fourth power tube is connected with the second power tube and the filter circuit, the sixth power tube is connected with the first power tube and the negative electrode of the power supply, and the two ends of the second diode are respectively connected with the first power tube and the filter circuit.

7. The method according to claim 6, characterized in that The second mode includes: a third mode and a fourth mode, wherein when the photovoltaic inverter operates in the third mode and the fourth mode, the number of current loops is different; controlling the photovoltaic inverter to operate in the second mode corresponding to the negative half cycle includes: Determine a first instantaneous value of a carrier signal and a second instantaneous value of a modulation signal, wherein the carrier signal is used to control the output of the photovoltaic inverter, and the modulation signal is used to modulate the first power tube and the second power tube; When the first instantaneous value is greater than the second instantaneous value, controlling the photovoltaic inverter to operate in the third mode; When the first instantaneous value is less than the second instantaneous value, the photovoltaic inverter is controlled to operate in the fourth mode.

8. The method according to claim 7, characterized in that Controlling the photovoltaic inverter to operate in the third mode includes: controlling the states of all power tubes in the second conversion circuit to be turned on, and controlling the states of other power tubes of the third type to be turned off, wherein the other power tubes of the third type are power tubes that do not belong to the second conversion circuit among all power tubes included in the photovoltaic inverter; Controlling the photovoltaic inverter to operate in the fourth mode includes: controlling the state of the first power tube to be disconnected, controlling the state of the fourth type of other power tubes to be turned on, and controlling the state of the third type of other power tubes to be disconnected, wherein the fourth type of other power tubes are power tubes other than the first power tube in the second conversion circuit.

9. The method according to claim 1, characterized in that: Determining a voltage cycle of the photovoltaic inverter operation, including: Determining a phase of a modulation signal, wherein the modulation signal is used to modulate the first power tube and the second power tube; When the phase is greater than 0, determining that the voltage cycle of the photovoltaic inverter is the positive half cycle; When the phase is less than 0, it is determined that the voltage cycle of the photovoltaic inverter is the negative half cycle.

10. A photovoltaic inverter, characterized in that: Photovoltaic inverters include: A power supply, a plurality of conversion circuits for converting an input voltage, and a filter circuit, wherein the input voltage is a voltage output by the power supply; The multiple conversion circuits share the following elements: the power supply, a first inductor connected to the power supply, a first power tube and a second power tube connected in parallel to the first inductor, wherein the first inductor remains in a conducting state during the operation of the photovoltaic inverter; The filter circuit is connected to the multiple conversion circuits through the third power tube and the fourth power tube in the photovoltaic inverter respectively.

11. A control device for a photovoltaic inverter, characterized in that: Applied to a photovoltaic inverter, wherein the photovoltaic inverter comprises: a power supply, a plurality of conversion circuits for converting an input voltage, wherein the input voltage is a voltage output by the power supply, and the plurality of conversion circuits share the following elements: the power supply, a first inductor connected to the power supply, a first power tube and a second power tube connected in parallel to the first inductor; The control device of the photovoltaic inverter includes: A determination module, used to determine a voltage cycle of the photovoltaic inverter, wherein the voltage cycle includes: a positive half cycle and a negative half cycle; A control module is used to control the photovoltaic inverter to operate a first conversion circuit among the multiple conversion circuits when the photovoltaic inverter operates in the positive half-cycle, and control the photovoltaic inverter to operate in a first type of mode corresponding to the positive half-cycle; when the photovoltaic inverter operates in the negative half-cycle, control the photovoltaic inverter to operate a second conversion circuit among the multiple conversion circuits, and control the photovoltaic inverter to operate in a second type of mode corresponding to the negative half-cycle, wherein when the photovoltaic inverter operates in different modes, different semiconductor devices in the photovoltaic inverter are in a conductive state.

12. A non-volatile storage medium, characterized in that: The non-volatile storage medium stores a computer program, wherein the control method of the photovoltaic inverter according to any one of claims 1 to 9 is executed by running the computer program in the device where the non-volatile storage medium is located.

13. An electronic device comprising a memory and a processor, characterized in that: A computer program is stored in the memory, and the processor is configured to execute the photovoltaic inverter control method according to any one of claims 1 to 9 through the computer program.

14. A computer program product comprising computer instructions, characterized in that When the computer instructions are executed by a processor, the steps of the photovoltaic inverter control method described in any one of claims 1 to 9 are implemented.

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