CN117833636A

CN117833636A - Control method of power conversion circuit, power conversion equipment and energy storage equipment

Info

Publication number: CN117833636A
Application number: CN202410028318.4A
Authority: CN
Inventors: 韩冰; 赵密; 陈熙; 王雷
Original assignee: Ecoflow Technology Ltd
Current assignee: Ecoflow Technology Ltd
Priority date: 2024-01-05
Filing date: 2024-01-05
Publication date: 2024-04-05

Abstract

The application provides a control method of a power conversion circuit, power conversion equipment and energy storage equipment. The control method comprises the following steps: acquiring the actual input current of the MPPT module; determining a reference power derating coefficient according to the actual input current and a preset current threshold, wherein the reference power derating coefficient is larger than or equal to 0 and smaller than or equal to 1; determining a first power derating coefficient of the AC/DC conversion module and a second power derating coefficient of the DC/DC conversion module according to the working mode of the power conversion circuit and the reference power derating coefficient; the output power limit of the alternating current end of the AC/DC conversion module is determined according to the first power derating coefficient, and/or the charging power limit of the second end of the DC/DC conversion module is determined according to the second power derating coefficient. The control method of the power conversion circuit can improve the safety and reliability of the power conversion circuit.

Description

Control method of power conversion circuit, power conversion equipment and energy storage equipment

Technical Field

The application relates to the technical field of photovoltaic energy storage, in particular to a control method of a power conversion circuit, power conversion equipment and energy storage equipment.

Background

Photovoltaic power generation technology is a technology that converts solar energy into electrical energy to power a load. In the related art, in order to fully utilize solar energy resources, a power conversion device is utilized to convert direct current generated by a photovoltaic module into alternating current for a load. Meanwhile, redundant energy of the photovoltaic module is stored into the energy storage device through the power conversion device, so that the energy storage device is controlled to provide energy for a load through the power conversion device when the solar energy resource is insufficient.

However, when the operating parameter of the photovoltaic module exceeds the standard relative to the power conversion device, for example, the rated conversion power of the photovoltaic module is greater than the rated input power of the photovoltaic module set by the power conversion device, the power conversion device is enabled to track the rated voltage upper limit set by the conventional standard, and the maximum power point of the photovoltaic module is not tracked. The current of the maximum power tracking (Maximum power point tracking, MPPT) module inside the power conversion device is caused to flow excessively, and even fire or electric leakage can be caused when the current flowing seriously, so that a great safety risk is caused.

Disclosure of Invention

In view of this, the present application provides a control method of a power conversion circuit, a power conversion device and an energy storage device, which can reduce the occurrence probability of an overcurrent of an MPPT module in the power conversion circuit, and improve the safety and reliability of the power conversion circuit.

The first aspect of the present application provides a control method of a power conversion circuit, where the power conversion circuit includes an MPPT module, an AC/DC conversion module, a DC/DC conversion module, and a DC bus. The first end of MPPT module is connected direct current busbar, and the second end of MPPT module is used for connecting photovoltaic module. The direct current end of the AC/DC conversion module is connected with a direct current bus, and the alternating current end of the AC/DC conversion module is used for connecting a power grid and a load through the alternating current bus. The first end of the DC/DC conversion module is connected with the direct current bus, and the second end of the DC/DC conversion module is used for being connected with the energy storage module. The control method comprises the following steps: acquiring the actual input current of the MPPT module; determining a reference power derating coefficient according to the actual input current and a preset current threshold, wherein the reference power derating coefficient is larger than or equal to 0 and smaller than or equal to 1; determining a first power derating coefficient of the AC/DC conversion module and a second power derating coefficient of the DC/DC conversion module according to the working mode of the power conversion circuit and the reference power derating coefficient; and determining an output power limit value of the alternating-current end of the AC/DC conversion module according to the first power derating coefficient and/or determining a charging power limit value of the second end of the DC/DC conversion module according to the second power derating coefficient so as to control the output power of the alternating-current end of the AC/DC conversion module to be smaller than or equal to the output power limit value, and the charging power of the second end of the DC/DC conversion module to be smaller than or equal to the charging power limit value.

In one embodiment, determining a first power derating coefficient of an AC/DC conversion module and a second power derating coefficient of the DC/DC conversion module based on an operating mode of the power conversion circuit and the power derating coefficient includes: when the power conversion circuit is in a self-power-on mode or a power-off mode, configuring a first power derating coefficient as 1 and configuring a second power derating coefficient as a reference power derating coefficient; when the power conversion circuit is in the grid-connected standby mode, the first power derating coefficient is configured as a reference power derating coefficient, and the second power derating coefficient is configured as 1.

In one embodiment, determining an output power limit of an AC side of the AC/DC conversion module from the first power derating coefficient and/or determining a charging power limit of a second side of the DC/DC conversion module from the second power derating coefficient comprises: acquiring rated output power of the AC/DC conversion module and rated charging power of the DC/DC conversion module; determining an output power limit according to the first power derating coefficient and the rated output power; and/or determining a charging power limit based on the second power derating coefficient and the rated charging power.

In one embodiment, determining the reference power derating factor based on the actual input current and the preset current threshold includes: acquiring a current deviation value according to an actual input current and a preset current threshold; and carrying out deviation adjustment on the current deviation value to obtain a deviation adjustment value, and determining a reference power derating coefficient according to the deviation adjustment value.

In one embodiment, determining the reference power derating factor based on the bias adjustment value includes: and performing amplitude limiting processing on the deviation regulating value, and taking the amplitude-limited deviation regulating value as a reference power derating coefficient.

In one embodiment, the MPPT module includes at least two MPPT units, each MPPT unit is configured to be connected to a photovoltaic module, determine a power derating coefficient according to an actual input current and a preset current threshold, and include: determining an initial power derating coefficient of each MPPT unit according to the actual input current of each MPPT unit and a corresponding preset current threshold value; the reference power derating coefficient is determined based on all of the initial power derating coefficients.

In one embodiment, determining the reference power derating coefficient from all of the initial power derating coefficients includes: the minimum value of all the initial power derating coefficients is determined as the reference power derating coefficient.

A second aspect of the present application provides a power conversion apparatus including a power conversion circuit and a controller. The power conversion circuit comprises an MPPT module, an AC/DC conversion module, a DC/DC conversion module and a direct current bus, wherein a first end of the MPPT module is connected with the direct current bus, and a second end of the MPPT module is used for being connected with the photovoltaic module; the direct current end of the AC/DC conversion module is connected with a direct current bus, and the alternating current end of the AC/DC conversion module is used for connecting a power grid and a load through the alternating current bus; the first end of the DC/DC conversion module is connected with the direct current bus, and the second end of the DC/DC conversion module is used for being connected with the energy storage module. The controller is configured to perform the control method of the power conversion circuit according to any one of the above.

In one embodiment, the MPPT module includes a first MPPT unit and a second MPPT unit, the photovoltaic module includes a first photovoltaic module and a second photovoltaic module, first ends of the first MPPT unit and the second MPPT unit are both connected to the dc bus, a second end of the first MPPT unit is used for connecting the first photovoltaic module, and a second end of the second MPPT unit is used for connecting the second photovoltaic module.

The third aspect of the application provides an energy storage device, the energy storage device comprises a power conversion circuit, an energy storage module and a controller, the power conversion circuit comprises an MPPT module, an AC/DC conversion module, a DC/DC conversion module and a direct current bus, a first end of the MPPT module is connected with the direct current bus, and a second end of the MPPT module is used for being connected with a photovoltaic module; the direct current end of the AC/DC conversion module is connected with a direct current bus, and the alternating current end of the AC/DC conversion module is used for connecting a power grid and a load through the alternating current bus; the first end of the DC/DC conversion module is connected with the direct current bus, and the second end of the DC/DC conversion module is connected with the energy storage module. The controller is configured to perform the control method of the power conversion circuit according to any one of the above.

According to the control method of the power conversion circuit, firstly, the power derating coefficient is determined according to the actual input current of the MPPT module and the preset current threshold, wherein the power derating coefficient is larger than or equal to 0, and the power derating coefficient is smaller than or equal to 1. And determining a first power derating coefficient of the AC/DC conversion module and a second power derating coefficient of the DC/DC conversion module according to the current working mode and the power derating coefficient of the power conversion circuit, so as to determine the output power limit value of the AC/DC conversion module according to the first power derating coefficient and/or determine the charging power limit value of the DC/DC conversion module according to the second power derating coefficient. The output power of the alternating-current end of the AC/DC conversion module is smaller than or equal to the output power limit value, and the charging power of the second end of the DC/DC conversion module is smaller than or equal to the charging power limit value. Because the first end of the MPPT module, the direct current end of the AC/DC conversion module and the first end of the DC/DC conversion module are connected to the direct current bus, on one hand, the input current of the MPPT module can be reduced by limiting the charging power of the DC/DC conversion module and/or the output power of the AC/DC conversion module, so that the occurrence probability of overcurrent of the MPPT module is reduced, and the safety and the reliability of the power conversion circuit are improved; on the other hand, the control method of the power conversion circuit can be flexibly applicable to various working conditions by combining the working modes of the power conversion circuit and selecting to limit the output power provided to a load and/or a power grid or limit the charging power provided to an energy storage module.

Drawings

In order to more clearly illustrate the technical solutions of the present application, the drawings that are required for the embodiments will be briefly described, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope of protection of the present application. Like elements are numbered alike in the various figures.

Fig. 1 is a circuit block diagram of a power conversion circuit according to an embodiment of the present application.

Fig. 2 is a flowchart illustrating a control method of a power conversion circuit according to an embodiment of the present application.

Fig. 3 is a schematic flow chart of the substeps of step S203 according to an embodiment of the present application.

Fig. 4 is a flowchart illustrating a control method of the power conversion circuit before executing step S203 according to an embodiment of the present application.

Fig. 5 is a schematic structural diagram of a switch module according to an embodiment of the present application.

Fig. 6 is a schematic flow chart of the substeps of step S204 according to an embodiment of the present application.

Fig. 7 is a schematic flow chart of the substeps of step S202 according to an embodiment of the present application.

Fig. 8 is a circuit block diagram of a power conversion circuit according to another embodiment of the present application.

Fig. 9 is a schematic flow chart of the substeps of step S202 according to another embodiment of the present application.

Fig. 10 is a circuit block diagram of a power conversion device according to an embodiment of the present application.

Fig. 11 is a circuit block diagram of an energy storage device according to an embodiment of the present application.

Fig. 12 is a block diagram of a control device according to an embodiment of the present application.

Detailed Description

The following description of the technical solutions in the embodiments of the present application will be made with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, but not all embodiments.

It is noted that when one component is considered to be "connected" to another component, it may be directly connected to the other component or intervening components may also be present. When an element is referred to as being "disposed" on another element, it can be directly on the other element or intervening elements may also be present. The terms "top," "bottom," "upper," "lower," "left," "right," "front," "rear," and the like are used herein for illustrative purposes only.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

Some embodiments will be described below with reference to the accompanying drawings. The following embodiments and features of the embodiments may be combined with each other without conflict.

For example, referring to fig. 1, fig. 1 is a circuit block diagram of a power conversion circuit 10 to which the technical scheme of the present application is applied. The power conversion circuit 10 may be applied to various power conversion devices or energy storage devices. The power conversion circuit 10 is at least connectable to the photovoltaic module 20, the grid 30, the load 40 and the energy storage module 50. In this way, the power conversion circuit 10 can store the direct current generated by the photovoltaic module 20 to the energy storage module 50. The power conversion circuit 10 may also convert the dc power generated by the photovoltaic module 20 into ac power for outputting to the power grid 30 and/or the load 40. The power conversion circuit 10 may also convert ac power input from the power grid 30 into dc power to charge the energy storage module 50.

The power conversion circuit 10 includes a maximum power point tracking (Maximum power point tracking, MPPT) module 110, an AC/DC conversion module (AC/DC conversion module) 120, a DC/DC conversion module (DC/DC conversion module) 130, and a DC BUS (including a positive DC BUS bus+ and a negative DC BUS-). A first end of MPPT module 110 is connected to the dc bus. A second end of MPPT module 110 is used to connect photovoltaic module 20. The DC end of the AC/DC conversion module 120 is connected to a DC bus. The AC side of the AC/DC conversion module 120 is used to connect the grid 30 and the load 40 via an AC bus (including neutral N and line L). A first end of the DC/DC conversion module 130 is connected to the DC bus. A second terminal of the DC/DC conversion module 130 is connected to the energy storage module 50. A capacitor module, for example a capacitor C1, is also connected between the positive dc BUS bus+ and the negative dc BUS-.

The MPPT module 110 is configured to regulate the voltage output by the photovoltaic module 20 to achieve maximum power tracking. MPPT module 110 may be, for example, a boost circuit. The maximum power tracking algorithm employed by MPPT module 110 is not limited in this application.

The AC/DC conversion module 120 is used to convert direct current received by the direct current terminal into alternating current in the inversion mode, or to convert alternating current received by the alternating current terminal into direct current in the rectification mode. The AC/DC conversion module 120 may be a bidirectional AC/DC conversion circuit, i.e., the same circuit may be used to implement both the inverting and rectifying functions.

Understandably, the AC/DC conversion module 120 may include a rectifying circuit and an inverter circuit. The switching logic and the duty ratio of the rectifying circuit and the inverting circuit are controlled, so that the mode switching between the rectifying mode and the inverting mode of the AC/DC conversion module 120 and the control of the output voltage are realized. It is understood that the AC/DC conversion module 120 may be an existing AC/DC conversion circuit, which is not limited herein.

The DC/DC conversion module 130 is configured to perform power conversion on the direct current received at the first end and output the direct current through the second end in the charging mode to charge the energy storage module 50, or configured to perform power conversion on the direct current received at the second end and output the direct current through the first end in the discharging mode to output the electric energy of the energy storage module 50 onto the DC bus. The DC/DC conversion module 130 may be a unidirectional DC/DC conversion module or a bidirectional DC/DC conversion module, which is not limited in this application.

Understandably, the DC/DC conversion module 130 may be implemented using existing LLC circuitry. Or the DC/DC conversion module 130 may be composed of a BUCK circuit, a BOOST circuit, and a driving circuit. Thus, the driving circuit controls the switching logic and the duty ratio of the BUCK circuit and the BOOST circuit, so as to control the DC/DC conversion module 130 to operate in the charging mode or the discharging mode and control the conversion voltage of the DC/DC conversion module 130.

The photovoltaic module 20 includes a number of photovoltaic panels. The photovoltaic panel outputs direct current to the power conversion circuit 10 by converting light energy into electric energy. The present application is not limited to the manner of connection of the photovoltaic panels in the photovoltaic module 20. For example, in some embodiments, the photovoltaic panels in the photovoltaic module 20 may be connected in series, in parallel, or connected in series followed by parallel, etc.

The power grid 30 may be, for example, a utility power grid. The application is not limited to the type of ac power of the power grid 30, and in other embodiments, the power grid 30 may be single-phase ac power, three-phase ac power, or other multi-phase ac power, etc.

The load 40 may be various types of electrical loads.

One or more series and/or parallel cells are disposed within the energy storage module 50. The energy storage module 50 is used to store or release energy. In some embodiments, the energy storage module 50 may be an energy storage device; in other embodiments, the energy storage module 50 may be any electronic device provided with a rechargeable battery, and the specific device type of the energy storage module 50 is not limited in this application.

However, in some scenarios, when the operating parameters of the photovoltaic module 20 are over-rated with respect to the power conversion circuit 10, for example, the rated conversion power of the photovoltaic module 20 is greater than the rated input power of the photovoltaic module set by the power conversion circuit 10, such that the upper voltage limit of the rated voltage set by the conventional standard is tracked by the power conversion circuit 10 and the maximum power point of the photovoltaic module 20 is not tracked. Resulting in current flow through MPPT module 110 within power conversion circuit 10. Even fire or electric leakage can be caused when overcurrent is serious, and the safety risk is high.

Based on the above, the control method of the power conversion circuit can reduce the occurrence probability of overcurrent of the MPPT module in the power conversion circuit and improve the safety and reliability of the power conversion circuit.

Referring to fig. 2, fig. 2 is a control method of a power conversion circuit according to an embodiment of the present application. It will be appreciated that the control method of the power conversion circuit may be performed by a controller (not shown in fig. 1) of the power conversion circuit 10. The control method comprises the following steps:

step S201: and acquiring the actual input current of the MPPT module.

Understandably, the actual input current of MPPT module 110 is the current output by photovoltaic module 20 to MPPT module 110. In some embodiments, a current sensor (e.g., a hall sensor), or other circuit or electronic device that may implement current sampling, may be provided at the second end of MPPT module 110 to obtain the actual input current at the second end of MPPT module 110. In other embodiments, a current sensor or other circuit or electronic device that can perform current sampling may be provided at the output of the photovoltaic module 20 to obtain the actual input current at the output of the photovoltaic module 20.

Step S202: and determining a reference power derating coefficient according to the actual input current and a preset current threshold, wherein the reference power derating coefficient is larger than or equal to 0 and smaller than or equal to 1.

Wherein the preset current threshold is used to characterize the maximum input current of MPPT module 110. For example, in some embodiments, the preset current threshold may be a rated current. In other embodiments, the preset current threshold may also be less than or equal to the current value that triggers the over-current protection of MPPT module 110.

The reference power derating coefficient is used to characterize the ratio of the current maximum output power of the MPPT module 110 to the rated output power. When the reference power derating coefficient is equal to 1, it indicates that the MPPT module 110 may output full power, for example, the output power is the rated output power, corresponding to the current actual input current; when the reference power derating coefficient is equal to 0, it is indicated that the output power of the MPPT module 110 should be 0 corresponding to the current actual input current.

In step S202, with the preset current threshold as the adjustment target, the actual input current is used as the feedback calculated value, and then the reference power derating coefficient is obtained by calculating through a deviation controller, such as a P controller (proportional controller ), a PI controller (proportional integral controller, proportional integral controller), a PID controller (Proportion Integration Differentiation, proportional-integral-derivative controller), and the like.

Step S203: and determining a first power derating coefficient of the AC/DC conversion module and a second power derating coefficient of the DC/DC conversion module according to the working mode of the power conversion circuit and the reference power derating coefficient.

Wherein the first power derating coefficient is used to characterize a ratio of an ideal output power of the AC side of the AC/DC conversion module 120 to a rated power of the AC side thereof. The second power derating coefficient is used to characterize the ratio between the desired charge power and the nominal charge power output by the second terminal of the DC/DC conversion module 130. It is understood that the first power derating factor is greater than or equal to 0 and the first derating factor is less than or equal to 1. The second power derating factor is greater than or equal to 0 and the second derating factor is less than or equal to 1.

In the power conversion circuit 10, since the first end of the MPPT module 110, the DC end of the AC/DC conversion module 120, and the first end of the DC/DC conversion module 130 are all connected to the DC bus. In this way, the output power of the MPPT module 110 can be used to supply to the AC/DC conversion module 120 and the DC/DC conversion module 130, and thus, by reducing the output power of the AC/DC conversion module 120 and the DC/DC conversion module 130, the output power of the MPPT module 110 can also be reduced. Thereby reducing the input power of the MPPT module 110, further reducing the input current of the MPPT module 110, reducing the probability of occurrence of overcurrent of the MPPT module 110, and improving the reliability and safety of the operation of the power conversion circuit 10.

In the embodiment of the present application, the power conversion circuit 10 has several operation modes according to different combinations of the connection states of the power conversion circuit 10 and the power grid 30, the load 40, and the charge-discharge modes of the DC/DC conversion module 130. In each operation mode, after the energy generated by the photovoltaic module 20 is input to the power conversion circuit, the specific energy paths are different, and the priorities of the energy demands of the modules involved in the energy paths are also different. Therefore, in step S203, the first power derating coefficient of the AC/DC conversion module 120 and the second power derating coefficient of the DC/DC conversion module 130 are determined according to the operation mode of the power conversion circuit 10 and the reference power derating coefficient, so that the energy demand priority of each module of the power conversion circuit 10 in the corresponding operation mode can be better satisfied while the input current of the MPPT module 110 is reduced.

Step S204: and determining an output power limit value of the alternating-current end of the AC/DC conversion module according to the first power derating coefficient and/or determining a charging power limit value of the second end of the DC/DC conversion module according to the second power derating coefficient so as to control the output power of the alternating-current end of the AC/DC conversion module to be smaller than or equal to the output power limit value, and the charging power of the second end of the DC/DC conversion module to be smaller than or equal to the charging power limit value.

As can be appreciated, the output power of the AC side of the AC/DC conversion module 120 is used to provide to the grid 30 and/or the load 40. The charging power of the second terminal of the DC/DC conversion module 130 is used to charge the energy storage module 50. In step S204, by limiting the output power of the AC end of the AC/DC conversion module 120 and the charging power of the second end of the DC/DC conversion module 130, the output power of the MPPT module 110 can be limited to limit the input current of the MPPT module 110, thereby reducing the occurrence probability of the overcurrent of the MPPT module 110.

In summary, in the control method of the power conversion circuit provided in the present application, a power derating coefficient is first determined according to an actual input current of the MPPT module 110 and a preset current threshold, where the power derating coefficient is greater than or equal to 0 and the power derating coefficient is less than or equal to 1. The first power derating coefficient of the AC/DC conversion module 120 and the second power derating coefficient of the DC/DC conversion module 130 are determined according to the current operation mode and the power derating coefficient of the power conversion circuit 10, so as to determine the output power limit of the AC/DC conversion module 120 according to the first power derating coefficient and/or determine the charging power limit of the DC/DC conversion module 130 according to the second power derating coefficient. Wherein the output power of the AC end of the AC/DC conversion module 120 is less than or equal to the output power limit value, and the charging power of the second end of the DC/DC conversion module 130 is less than or equal to the charging power limit value. Since the first end of the MPPT module 110, the DC end of the AC/DC conversion module 120 and the first end of the DC/DC conversion module 130 are all connected to the DC bus, the input current of the MPPT module 110 can be reduced by limiting the charging power of the DC/DC conversion module 130 and the output power of the AC/DC conversion module 120, so that the occurrence probability of the overcurrent of the MPPT module 110 is reduced, and the safety and reliability of the power conversion circuit 10 are improved; on the other hand, in combination with the operation mode of the power conversion circuit 10, the output power provided to the load 40 and/or the power grid 30 is limited or the charging power provided to the energy storage module 50 is limited, so that the control method of the power conversion circuit can be flexibly applied to various working conditions.

Referring to fig. 3, in some embodiments, in the case that the rated output power of the MPPT module 110, the rated output power of the AC end of the AC/DC conversion module 120, and the rated charging power of the DC/DC conversion module 130 are equal, step S203 includes the following sub-steps:

step S301: when the power conversion circuit is in the self-power-on mode or the off-grid standby mode, the first power derating coefficient is configured to be 1, and the second power derating coefficient is configured to be the reference power derating coefficient.

The self-power-use mode refers to a mode in which the power generated by the photovoltaic module 20 in the power conversion circuit 10 is used for the load 40 and is not fed into the power grid 30, and the surplus power supplied by the photovoltaic module 20 to the load 40 can be stored in the energy storage module 50, and the energy stored in the energy storage module 50 can be supplied to the load 40 when the illumination is insufficient (e.g. at night). The off-grid standby mode refers to that when the power conversion circuit 10 is disconnected from the power grid 30, the generated power of the photovoltaic module 20 is stored in the energy storage module 50, and the photovoltaic module 20 supplies power to the load 40.

It should be appreciated that, in the self-power-on mode and the off-grid standby mode, since the power grid 30 is not used to supply power to the load 40, the output power of the AC terminal of the AC/DC conversion module 120 should be kept at the full power output as much as possible in order to ensure the power supply to the load 40. In this way, in step S301, when the power conversion circuit 10 is in the self-power-on mode or the off-grid standby mode, the power supply of the load 40 is ensured while reducing the charging power of the DC/DC conversion module 130 to reduce the input current of the MPPT module 110 by configuring the first power derating coefficient to be 1 and configuring the second power derating coefficient to be the reference power derating coefficient.

Step S302: when the power conversion circuit is in the grid-connected standby mode, the first power derating coefficient is configured as a reference power derating coefficient, and the second power derating coefficient is configured as 1.

The grid-connected standby mode refers to that when the power conversion circuit 10 is connected to the power grid 30, the power generated by the photovoltaic module 20 is stored in the energy storage module 50, and the AC/DC conversion module 120 takes power from the power grid 30 to charge the energy storage module 50. In grid-tied standby mode, load 40 may be powered by grid 30. Therefore, in the grid-connected standby mode, charging of the energy storage module 50 should be preferentially ensured, and power supply of the load 40 may be provided by the power grid 30. In this way, the first power derating coefficient may be configured as the reference power derating coefficient and the second power derating coefficient may be configured as 1 in the grid-connected standby mode, so as to reduce the output power of the AC end of the AC/DC conversion module 120 to reduce the input current of the MPPT module 110, and ensure that the energy storage module 50 charges with the maximum charging power.

It is understood that in other embodiments, when the power conversion circuit 10 is in the self-power mode or the off-grid standby mode, the first power derating coefficient is configured to be 1, and the second power derating coefficient may be configured to be other values. The second power derating coefficient is only required to make the value of the reduced charging power of the DC/DC conversion module 130 greater than or equal to the value of the reduced output power of the MPPT module 110 calculated according to the reference power derating coefficient.

Similarly, in other embodiments, when the power conversion circuit 10 is in the grid-connected standby mode and the second power derating coefficient is configured to be 1, the value of the first power derating coefficient may be configured to be other values. The first power derating coefficient is only required to enable the value of the output power of the AC end of the AC/DC conversion module 120 to be reduced to be greater than or equal to the value of the output power of the MPPT module 110 calculated according to the reference power derating coefficient.

In summary, by executing steps S301 to S302, the input current of the MPPT module 110 can be reduced in cooperation with various operation modes of the power conversion circuit 10, so as to reduce the occurrence probability of the overcurrent of the MPPT module 110.

Referring to fig. 4, in some embodiments, before performing step S203, the control method further includes:

step S401: the method comprises the steps of obtaining a first connection state of an AC/DC conversion module and a power grid and a second connection state of the AC/DC conversion module and a load.

It will be appreciated that as shown in fig. 5, a switch module is disposed between the AC/DC conversion module 120 and the power grid 30, other switch modules are also disposed between the AC/DC conversion module 120 and the load 40, and related switch modules are also disposed between the power grid 30 and the load 40. In this manner, by detecting the state (e.g., on state or off state) of the switching module between the AC/DC conversion module 120 and the grid 30, a first connection state may be obtained; the second connection state may be obtained by detecting the state of the switching module between the AC/DC conversion module 120 and the load 40.

It will be appreciated that the switch module includes, but is not limited to, a transistor, a mechanical switch, a knife, or the like, and the specific type of switch module is not limited by the present application. In the embodiment of the application, the switch module realizes the related switch function through the relay.

It will be appreciated that in other embodiments, the first connection state may also be obtained by obtaining the current or voltage of the interface of the AC/DC conversion module 120 connected to the power grid 30. For example, when the current of the interface of the AC/DC conversion module 120 connected to the power grid 30 exceeds a preset current threshold (or the voltage exceeds a preset voltage threshold), the first connection state may be determined to be the conductive state; when the current of the interface of the AC/DC conversion module 120 connected to the power grid 30 is less than the preset current threshold (or the voltage is less than the preset voltage threshold), it may be determined that the first connection state is the disconnection state. Similarly, the second connection state may also be obtained by obtaining the current or the voltage of the interface of the AC/DC conversion module 120 connected to the load 40, which is not described herein.

Step S402: and acquiring the working mode of the DC/DC conversion module.

The operation modes of the DC/DC conversion module 130 include a charge mode and a discharge mode.

In some embodiments, when the DC/DC conversion module 130 is composed of a BUCK circuit, a BOOST circuit and a driving circuit, and the switching logic and the duty ratio of the BUCK circuit and the BOOST circuit are controlled by the driving circuit, the DC/DC conversion module 130 is controlled to operate in the charging mode or the discharging mode, the driving signal of the driving circuit can be obtained to determine the operating mode of the DC/DC conversion module 130.

In other embodiments, the operation mode of the DC/DC conversion module 130 may also be determined by obtaining the current direction of the first end of the DC/DC conversion module 130. For example, when the direction of the current at the first end of the DC/DC conversion module 130 is from the first end of the DC/DC conversion module 130 to the DC bus, the operation mode of the DC/DC conversion module 130 may be determined to be the discharge mode; when the direction of the current flowing from the direct current bus to the first end of the DC/DC conversion module 130 is the first end of the DC/DC conversion module 130, the operation mode of the DC/DC conversion module 130 may be determined to be the charging mode.

Step S403: when the first connection state is in an off state, the second connection state is in an on state, and the working mode is in a charging mode, the power conversion circuit is determined to be in a spontaneous self-use mode.

Specifically, referring to fig. 5, a grid-connected relay (K11/K12/K31/K32) is provided between the AC/DC conversion module 120 and the power grid 30, an off-grid relay (K21/K22) is provided between the AC/DC conversion module 120 and the load 40, and a bypass relay (K41/K42/K51/K52) is also provided between the power grid 30 and the load 40. When the power conversion circuit 10 is in the self-service mode, the off-grid relay is in a closed state, and the bypass relay and the on-grid relay are both in an open state. Referring to fig. 1 and 5, in the self-service mode, if the load 40 has a power demand, the power conversion circuit 10 uses the electric energy provided by the photovoltaic module 20 to power the load 40 and charges the energy storage module 50. At this time, the power conversion circuit 10 does not transmit power to the power grid 30, and does not draw power from the power grid 30.

Step S404: and when the first connection state is in a conducting state, the second connection state is in a disconnecting state and the working mode is in a charging mode, determining that the power conversion circuit is in a grid-connected standby mode.

Specifically, when the power conversion circuit 10 is in the grid-connected standby mode, the off-grid relay is in an open state, and the grid-connected relay is in a closed state. Referring to fig. 1 and 5, in the grid-connected standby mode, the power conversion circuit 10 charges the energy storage module 50 with the electric energy of the power grid 30 to ensure that the electric quantity of the energy storage module 50 is within a preset electric quantity range. If the load 40 has a power demand, the power conversion circuit 10 will close the bypass relay to power the load 40 with the grid 30.

Step S405: and when the first connection state is in the disconnection state, the second connection state is in the disconnection state and the working mode is in the charging mode, determining that the power conversion circuit is in the off-grid standby mode.

Specifically, when the power conversion circuit 10 is in the off-grid standby mode, both the off-grid relay and the on-grid relay are in an off state. Referring to fig. 1 and fig. 5, in the off-grid standby mode, the power conversion circuit 10 charges the energy storage module 50 with the electric energy photoelectrically converted by the photovoltaic module 20 to ensure that the electric quantity of the energy storage module 50 is within the preset electric quantity range. If the load 40 has a power demand, the power conversion circuit 10 will close the bypass relay to power the load 40 with the grid 30.

In this way, after the first connection state, the second connection state, and the operation mode of the DC/DC conversion module 130 are acquired, the operation mode of the power conversion circuit 10 can be determined through steps S403 to S405.

In other embodiments, other operation modes of the power conversion circuit 10 may be set according to practical situations, and are not limited herein.

Referring to fig. 6, in some embodiments, step S204 includes:

step S601: and acquiring the rated output power of the AC/DC conversion module and the rated charging power of the DC/DC conversion module.

It will be appreciated that in some embodiments, the AC side of the AC/DC conversion module 120 is provided with a rated output power. A second terminal of the DC/DC conversion module 130 is provided with a rated charging power. And the rated output power is the maximum output power of the AC end of the AC/DC conversion module 120. The rated charging power is the maximum charging power of the DC/DC conversion module 130.

Step S602: determining an output power limit according to the first power derating coefficient and the rated output power; and/or

And determining a charging power limit value according to the second power derating coefficient and the rated charging power.

In some embodiments, the product of the first power derating coefficient and the rated output power may be taken as the output power limit. And taking the product of the second power derating coefficient and the rated charging power as the charging power limit value.

It will be appreciated that the present application is not limited to a specific calculation formula for determining the output power limit according to the first power derating coefficient and the rated output power, nor is it limited to a specific calculation formula for determining the charge power limit according to the second power derating coefficient and the rated charge power. In other embodiments, other calculation parameters may be added based on factors such as power loss in the power conversion circuit 10 to determine the output power limit according to the first power derating coefficient and the rated output power. In other embodiments, the charging power limit may be determined from the second power derating coefficient and the rated charging power.

In summary, by executing steps S601 to S602, an output power limit and a charging power limit can be calculated according to the first power derating coefficient and the second power derating coefficient, respectively, so as to limit the output power of the AC end of the AC/DC conversion module 120; and/or the charging power of the second terminal of the DC/DC conversion module 130.

Referring to fig. 7, in some embodiments, step S202 includes:

step S701: and obtaining a current deviation value according to the actual input current and a preset current threshold.

The current deviation value is used for representing the difference between the preset current threshold value and the actual input current.

In some embodiments, the difference obtained by subtracting the actual input current from the preset current threshold may be used as the current deviation value.

Step S702: and carrying out deviation adjustment on the current deviation value to obtain a deviation adjustment value, and determining a reference power derating coefficient according to the deviation adjustment value.

It is understood that the deviation adjustment of the current deviation value may be performed by proportional integral adjustment or proportional adjustment. For example, the deviation adjustment value can be calculated by inputting the current deviation value into a proportional integral regulator or a proportional regulator. Specifically, steps S701 and S702 may be implemented by a current loop with a proportional integral regulator or a proportional regulator.

It is appreciated that in some embodiments, when the calculated bias adjustment value is greater than or equal to 0 and the bias adjustment value is less than or equal to 1, the bias adjustment value may be directly taken as the reference power derating coefficient.

In other embodiments, determining the reference power derating factor based on the bias adjustment value includes:

and performing amplitude limiting processing on the deviation regulating value, and taking the amplitude-limited deviation regulating value as a reference power derating coefficient.

The clipping processing of the deviation adjustment value means that the minimum value of the deviation adjustment value is limited to 0 and the maximum value of the deviation adjustment value is limited to 1.

It is understood that when the actual input current is too large, the calculated deviation adjustment value may be smaller than 0, and thus, the deviation adjustment value is limited to 0 by performing a clipping process on the deviation adjustment value smaller than 0. At this time, the deviation adjustment value of 0 obtained after clipping is used as the reference power derating coefficient, and the output power of the AC end of the AC/DC conversion module 120 and the charging power of the second end of the DC/DC conversion module 130 can be controlled to be 0, so as to control the MPPT module 110 to stop outputting power, thereby rapidly reducing the input current of the MPPT module 110. When the actual input current is excessively small, the calculated deviation adjustment value may be greater than 1, and thus, the deviation adjustment value is limited to 1 by performing a clipping process on the deviation adjustment value greater than 1. At this time, the deviation adjustment value of 1 obtained after clipping is taken as a reference power derating coefficient, so that the MPPT module 110 can be controlled to output according to the rated output power.

In summary, by executing the above steps, the reference power derating coefficient can be calculated according to the actual input current and the preset current threshold based on the deviation adjustment.

In some embodiments, MPPT module 110 also includes at least two MPPT units. Each MPPT unit is used for being connected with the photovoltaic module. For example, referring to fig. 8, in some embodiments, MPPT module 110 includes a first MPPT unit 111 and a second MPPT unit 112. The photovoltaic module 20 includes a first photovoltaic module 21 and a second photovoltaic module 22. The first ends of the first MPPT unit 111 and the second MPPT unit 112 are both connected to the dc bus. A second end of first MPPT unit 111 is used to connect first photovoltaic module 21. A second end of second MPPT unit 112 is used to connect to second photovoltaic module 22.

In such a power conversion circuit 10 shown in fig. 8, the power conversion circuit 10 is connected to at least two groups of photovoltaic modules. In this case, a scenario in which the operating parameters of the photovoltaic module may be out of standard with respect to the power conversion circuit may be: the first photovoltaic module 21 corresponds to the rated power of the photovoltaic module set by the power conversion circuit 10, but the second photovoltaic module 22 does not correspond to the rated power of the photovoltaic module set by the power conversion circuit 10, for example, the rated power of the second photovoltaic module 22 is greater than the rated power of the photovoltaic module set by the power conversion circuit 10. In this scenario, if the second photovoltaic module 22 is replaced, the cost of the user is definitely increased, but if the second photovoltaic module 22 is not replaced, in an extreme case, when the first photovoltaic module 21 has no energy output due to light shielding, the second photovoltaic module 22 is fully illuminated, but because the second photovoltaic module 22 is out of standard, the second MPPT unit 112 tracks the normal standard set rated voltage upper limit and does not track the maximum power point, at this time, the energy storage module 50 is charged through the DC/DC conversion module 130 and the AC/DC conversion module 120 supplies power to the load 40, and the second MPPT unit 112 of the power conversion circuit 10 bears all the power charged and inverted to be carried and exceeds the designed rated power. In this case, even if the second MPPT unit 112 is controlled to stop operating, the generated power of the second photovoltaic module 22 may still flow to the bus capacitor (e.g., the capacitor C1 in fig. 8). That is, even if the second MPPT unit 112 is controlled to stop working, the second photovoltaic module 22 may cause the input current of the MPPT module 110 to flow, thereby causing the power conversion circuit 10 to stop frequently, and affecting the use experience. Therefore, in the power conversion circuit 10 shown in fig. 8, the scheme of limiting the input current of the MPPT module 110 by controlling the output power of the rear end of the MPPT module 110 (for example, the output power of the AC end of the AC/DC conversion module 120 and the charging power of the second end of the DC/DC conversion module 130) is also applicable.

In this way, when the MPPT module 110 includes at least two MPPT units, the control method of the power conversion circuit provided in any of the embodiments above may be executed to reduce the occurrence probability of the overcurrent of the MPPT module 110, which is different when executing the step S202.

Specifically, referring to fig. 9, when MPPT module 110 includes at least two MPPT units, step S202 includes the following sub-steps:

step S901: and determining an initial power derating coefficient of each MPPT unit according to the actual input current of each MPPT unit and a corresponding preset current threshold value.

The specific calculation process of determining the initial power derating coefficient of each MPPT unit in step S901 is basically the same as the process of performing clipping processing after calculating the deviation adjustment value in steps S701 to S702, and will not be described herein.

Step S902: the reference power derating coefficient is determined based on all of the initial power derating coefficients.

Understandably, since the first ends of all MPPT units are connected to the dc bus. Accordingly, to ensure that all MPPT units in MPPT module 110 are not over-current, the reference power derating coefficient should be determined based on all initial power derating coefficients.

Specifically, in some embodiments, step S902 further comprises:

The minimum value of all the initial power derating coefficients is determined as the reference power derating coefficient.

Thus, the safety and reliability of the power conversion circuit 10 can be improved.

Referring to fig. 10, the present application further provides a power conversion apparatus 100, including a power conversion circuit 10 and a controller 140. The power conversion circuit 10 includes an MPPT module 110, an AC/DC conversion module 120, a DC/DC conversion module 130, and DC buses (positive DC BUS BUS+ and negative DC BUS BUS-). The first end of the MPPT module 110 is connected to the dc bus, and the second end of the MPPT module 110 is connected to the photovoltaic module 20. The DC end of the AC/DC conversion module 120 is connected to a DC bus, and the AC end of the AC/DC conversion module 120 is connected to the grid 30 and the load 40 via the AC bus. A first end of the DC/DC conversion module 130 is connected to the DC bus. A second terminal of the DC/DC conversion module 130 is connected to the energy storage module 50. The controller 140 is configured to execute the control method of the power conversion circuit according to any of the above embodiments. In some embodiments, the power conversion circuit further comprises a switching module, through which the AC end of the AC/DC conversion module 120 is further connected to the load 40, the grid 30. By controlling the switching module, connection between the AC end of the AC/DC conversion module 120 and the power grid 30, between the AC end of the AC/DC conversion module 120 and the load 40, and between the power grid 30 and the load 40 can be achieved.

In some embodiments, MPPT module 110 includes a first MPPT unit 111 and a second MPPT unit 112. The photovoltaic module 20 includes a first photovoltaic module 21 and a second photovoltaic module 22. The first ends of the first MPPT unit 111 and the second MPPT unit 112 are both connected to the dc bus. A second end of the first MPPT unit 111 is used to connect to the first photovoltaic module 21, and a second end of the second MPPT unit 112 is used to connect to the second photovoltaic module 22.

Referring to fig. 11, the present application further provides an energy storage device 200. The energy storage device 200 includes a power conversion circuit 10, an energy storage module 50, and a controller 140. The power conversion circuit 10 includes an MPPT module 110, an AC/DC conversion module 120, a DC/DC conversion module 130, and a DC bus. The first end of the MPPT module 110 is connected to the dc bus, and the second end of the MPPT module 110 is connected to the photovoltaic module 20. The DC end of the AC/DC conversion module 120 is connected to a DC bus. The AC side of the AC/DC conversion module 120 is used to connect the grid 30 and the load 40 via an AC bus. A first end of the DC/DC conversion module 130 is connected to the DC bus. A second terminal of the DC/DC conversion module 130 is connected to the energy storage module 50. The controller 140 is configured to execute the control method of the power conversion circuit according to any of the above embodiments.

It is understood that the energy storage device 200 may be various electronic devices provided with the energy storage module 50, such as a mobile energy storage device, a home energy storage device, a mobile air conditioner, a mobile refrigerator, etc., and the present application is not limited to the specific functions of the energy storage device 200.

It is understood that the controller 140 may be a processor independent of the energy storage module 50 and the power conversion circuit 10, and the controller 140 may be a processor disposed in the power conversion device 100 or the energy storage device 200. The specific form of the controller 140 is not limited in this application.

An embodiment of the present application further provides a control device applied to the power conversion circuit 10 or the electronic device integrated with the power conversion circuit 10. Fig. 12 schematically shows a block diagram of a control device 300 according to an embodiment of the present application. As shown in fig. 12, the control device 300 includes:

the obtaining module 310 is configured to obtain an actual input current of the MPPT module 110.

The first determining module 320 is configured to determine a reference power derating coefficient according to the actual input current and the preset current threshold, where the reference power derating coefficient is greater than or equal to 0 and the reference power derating coefficient is less than or equal to 1.

The second determining module 330 is configured to determine a first power derating coefficient of the AC/DC converting module 120 and a second power derating coefficient of the DC/DC converting module 130 according to the operation mode of the power converting circuit 10 and the reference power derating coefficient.

The control module 340 is configured to determine an output power limit of the AC end of the AC/DC conversion module 120 according to the first power derating coefficient, and/or determine a charging power limit of the second end of the DC/DC conversion module 130 according to the second power derating coefficient, so as to control the output power of the AC end of the AC/DC conversion module 120 to be less than or equal to the output power limit, and the charging power of the second end of the DC/DC conversion module 130 to be less than or equal to the charging power limit.

Specific details of the control method for implementing the power conversion circuit by the control device 300 provided in the embodiments of the present application have been described in detail in the embodiments of the control method for corresponding power conversion circuit, and are not described herein again.

The present application also provides a computer-readable medium having stored thereon a computer program which, when executed by a processor, implements a control method of a power conversion circuit as in the above technical solutions. The computer readable medium may take the form of a portable compact disc read only memory (CD-ROM) and include program code that can be run on a terminal device, such as a personal computer. However, the program product of the present invention is not limited thereto, and in this document, a readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

The program product described above may take the form of any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. The readable storage medium can be, for example, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or a combination of any of the foregoing. More specific examples (a non-exhaustive list) of the readable storage medium would include the following: an electrical connection having one or more wires, a portable disk, a hard disk, random Access Memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

The computer readable signal medium may include a data signal propagated in baseband or as part of a carrier wave with readable program code embodied therein. Such a propagated data signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination of the foregoing. A readable signal medium may also be any readable medium that is not a readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.

Program code embodied on a readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

Program code for carrying out operations of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computing device, partly on the user's device, as a stand-alone software package, partly on the user's computing device, partly on a remote computing device, or entirely on the remote computing device or server. In the case of remote computing devices, the remote computing device may be connected to the user computing device through any kind of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or may be connected to an external computing device (e.g., connected via the Internet using an Internet service provider).

Furthermore, the above-described drawings are only schematic illustrations of processes included in the method according to the exemplary embodiment of the present invention, and are not intended to be limiting. It will be readily appreciated that the processes shown in the above figures do not indicate or limit the temporal order of these processes. In addition, it is also readily understood that these processes may be performed synchronously or asynchronously, for example, among a plurality of modules.

The foregoing is merely a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any equivalent modifications or substitutions will be apparent to those skilled in the art within the scope of the present application, and these modifications or substitutions should be covered in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. The control method of the power conversion circuit is characterized in that the power conversion circuit comprises an MPPT module, an AC/DC conversion module, a DC/DC conversion module and a direct current bus, wherein a first end of the MPPT module is connected with the direct current bus, and a second end of the MPPT module is used for being connected with a photovoltaic module; the direct current end of the AC/DC conversion module is connected with the direct current bus, and the alternating current end of the AC/DC conversion module is used for connecting a power grid and a load through the alternating current bus; the first end of the DC/DC conversion module is connected with the direct current bus, the second end of the DC/DC conversion module is used for being connected with the energy storage module, and the control method comprises the following steps:

acquiring the actual input current of the MPPT module;

determining a reference power derating coefficient according to the actual input current and a preset current threshold, wherein the reference power derating coefficient is greater than or equal to 0 and is less than or equal to 1;

Determining a first power derating coefficient of the AC/DC conversion module and a second power derating coefficient of the DC/DC conversion module according to the working mode of the power conversion circuit and the reference power derating coefficient;

and determining an output power limit value of an alternating-current end of the AC/DC conversion module according to the first power derating coefficient and/or determining a charging power limit value of a second end of the DC/DC conversion module according to the second power derating coefficient so as to control the output power of the alternating-current end of the AC/DC conversion module to be smaller than or equal to the output power limit value, wherein the charging power of the second end of the DC/DC conversion module is smaller than or equal to the charging power limit value.

2. The method of claim 1, wherein determining the first power derating coefficient of the AC/DC conversion module and the second power derating coefficient of the DC/DC conversion module based on the operating mode of the power conversion circuit and the power derating coefficient comprises:

when the power conversion circuit is in a self-power-on mode or an off-grid standby mode, configuring the first power derating coefficient to be 1, and configuring the second power derating coefficient to be the reference power derating coefficient;

When the power conversion circuit is in a grid-connected standby mode, the first power derating coefficient is configured to be the reference power derating coefficient, and the second power derating coefficient is configured to be 1.

3. The method according to claim 1, wherein said determining an output power limit of an AC side of the AC/DC conversion module from the first power derating coefficient and/or determining a charging power limit of a second side of the DC/DC conversion module from the second power derating coefficient comprises:

acquiring rated output power of the AC/DC conversion module and rated charging power of the DC/DC conversion module;

determining the output power limit according to the first power derating coefficient and the rated output power; and/or

And determining the charging power limit value according to the second power derating coefficient and the rated charging power.

4. The method of claim 1, wherein said determining a reference power derating factor based on the actual input current and a preset current threshold comprises:

acquiring a current deviation value according to the actual input current and the preset current threshold;

and carrying out deviation adjustment on the current deviation value to obtain a deviation adjustment value, and determining the reference power derating coefficient according to the deviation adjustment value.

5. The method of claim 4, wherein said determining said reference power derating factor from said bias adjustment value comprises:

and carrying out amplitude limiting processing on the deviation regulating value, and taking the amplitude-limited deviation regulating value as the reference power derating coefficient.

6. The method of claim 1, wherein the MPPT module includes at least two MPPT units, each of the MPPT units being configured to be connected to a photovoltaic module, the determining a power derating coefficient based on the actual input current and a preset current threshold value comprising:

determining an initial power derating coefficient of each MPPT unit according to the actual input current of each MPPT unit and a corresponding preset current threshold;

and determining the reference power derating coefficient according to all the initial power derating coefficients.

7. The method of claim 6, wherein said determining said reference power derating factor from all of said initial power derating factors comprises:

and determining the minimum value of all the initial power derating coefficients as the reference power derating coefficient.

8. The power conversion equipment is characterized by comprising a power conversion circuit and a controller, wherein the power conversion circuit comprises an MPPT module, an AC/DC conversion module, a DC/DC conversion module and a direct current bus, a first end of the MPPT module is connected with the direct current bus, and a second end of the MPPT module is used for being connected with a photovoltaic module; the direct current end of the AC/DC conversion module is connected with the direct current bus, and the alternating current end of the AC/DC conversion module is used for connecting a power grid and a load through the alternating current bus; a first end of the DC/DC conversion module is connected to the direct current bus, a second end of the DC/DC conversion module is connected to the energy storage module, and the controller is configured to perform the control method of the power conversion circuit according to any one of claims 1 to 7.

9. The power conversion apparatus of claim 8, wherein: the MPPT module comprises a first MPPT unit and a second MPPT unit, the photovoltaic module comprises a first photovoltaic module and a second photovoltaic module, the first MPPT unit and the first end of the second MPPT unit are both connected with the direct current bus, the second end of the first MPPT unit is used for being connected with the first photovoltaic module, and the second end of the second MPPT unit is used for being connected with the second photovoltaic module.

10. The energy storage device is characterized by comprising a power conversion circuit, an energy storage module and a controller, wherein the power conversion circuit comprises an MPPT module, an AC/DC conversion module, a DC/DC conversion module and a direct current bus, a first end of the MPPT module is connected with the direct current bus, and a second end of the MPPT module is used for being connected with a photovoltaic module; the direct current end of the AC/DC conversion module is connected with the direct current bus, and the alternating current end of the AC/DC conversion module is used for connecting a power grid and a load through the alternating current bus; a first end of the DC/DC conversion module is connected to the DC bus, a second end of the DC/DC conversion module is connected to the energy storage module, and the controller is configured to perform the control method of the power conversion circuit according to any one of claims 1 to 7.