WO2020186562A1

WO2020186562A1 - Converter and control method therefor

Info

Publication number: WO2020186562A1
Application number: PCT/CN2019/081447
Authority: WO
Inventors: 张为民; 周一晨
Original assignee: 合肥为民电源有限公司
Priority date: 2019-03-18
Filing date: 2019-04-04
Publication date: 2020-09-24
Also published as: CN109787298A

Abstract

Provided is a converter applied to a power system, with the power system comprising a first power supply apparatus, an energy storage apparatus, a second power supply apparatus and a load. The converter comprises a first power supply control module, a bidirectional inversion control module, a main control module, a direct-current busbar and an alternating-current busbar. The direct-current busbar is connected to the energy storage apparatus, is connected to the first power supply apparatus by means of the first power supply control module, and is connected to the alternating-current busbar by means of the bidirectional inversion control module; the alternating-current busbar is connected to the load and the second power supply apparatus; the main control module is connected to the first power supply control module, and is used for converting electric energy output by the first power supply apparatus into a direct current power with parameters matching power source parameters of the energy storage apparatus; and the main control module is connected to the bidirectional inversion control module, and is used for controlling the bidirectional inversion control module to perform mutual conversion between an alternating current power on the alternating-current busbar and a direct current power on the direct-current busbar. By using the present application, the circuit structure of the converter is simplified, and the energy storage apparatus can be reversely charged.

Description

Converter and its control method

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office on March 18, 2019 with the application number 201910203670.6 and the invention title is "a converter and its control method", the entire content of which is incorporated into this application by reference in.

Technical field

This application relates to the field of power technology, in particular to a converter and its control method.

Background technique

With the rapid growth of power demand and the increasing attention of countries around the world to environmental protection and the development and utilization of renewable energy, power systems composed of wind, solar, and diesel power generation devices combined with energy storage devices and power grids have gradually become an important research direction. Among them, the power system requires a converter to connect wind, solar, and diesel power generation devices, energy storage devices, power grids, and loads to coordinate power supply to the load.

Referring to Figure 1, in the prior art, a converter includes a unidirectional DC (Direct Current, direct current)/DC conversion circuit, an AC (Alternating current, alternating current)/DC rectifier circuit, a bidirectional DC/DC conversion circuit, and a unidirectional DC/DC conversion circuit. AC inverter circuit and main control module. Among them, photovoltaic power generation components are connected to the DC bus through a unidirectional DC/DC conversion circuit; the wind generator is connected to the DC bus through an AC/DC rectifier circuit; a bidirectional DC/DC conversion circuit is connected between the DC bus and the battery; the DC bus passes through The unidirectional DC/AC inverter circuit is connected to the AC bus; the AC bus is connected to the load; the AC bus is connected to the diesel generator or the power grid. The main control module controls the unidirectional DC/AC inverter circuit to convert the DC power on the DC bus into AC power and transmit it to the AC bus to supply power to the load. When the power on the DC bus is insufficient to supply the load, diesel power generation The machine or the grid can supply power to the load.

In the prior art, the converter at least includes a unidirectional DC/DC conversion circuit, a bidirectional DC/DC conversion circuit, an AC/DC rectifier circuit, and a unidirectional DC/AC inverter circuit. The circuit structure is relatively complicated and The DC bus and the AC bus are connected by a one-way DC/AC inverter circuit. The one-way DC/AC inverter circuit can only convert the DC power on the DC bus into AC power, which is transmitted to the AC bus and the power supply on the AC side (Diesel generator or grid) When supplying power to the load, the power supply on the AC side cannot reversely charge the energy storage device through the unidirectional DC/AC inverter circuit.

Summary of the invention

The purpose of the embodiments of the present application is to provide a converter and a control method thereof, which can simplify the circuit structure of the converter and enable the AC side power supply to charge the energy storage device in reverse. The specific technical plan is as follows:

In a first aspect, a converter is provided, which is applied to a power system. The power system includes a first power supply device, an energy storage device, a second power supply device, and a load, and the converter includes: a first power supply control module , Two-way inverter control module, main control module, DC bus and AC bus; wherein: the input end of the first power supply control module is connected to the output end of the first power supply device, and the output of the first power supply control module Terminal is connected to the DC bus; the energy storage device is connected to the DC bus; the DC side of the bidirectional inverter control module is connected to the DC bus, and the AC side of the bidirectional control module is connected to the AC bus Connection; the AC bus is connected to the load and the second power supply device; the main control module is connected to the first power supply control module for converting the electrical energy output by the first power supply device into The direct current that matches the power supply parameters of the energy storage device, and the converted direct current is delivered to the direct current bus; the main control module is connected to the bidirectional inverter control module for controlling the bidirectional inverter control The module converts the AC power on the AC bus into DC power, and transmits the converted DC power to the DC bus, or controls the bidirectional inverter control module to convert the DC power on the DC bus into AC power, and The converted AC power is delivered to the AC bus.

Optionally, the first power supply device includes a wind power generator and a photovoltaic power generation component; the first power supply control module includes a wind power generation control module and a photovoltaic power generation control module; the input end of the wind power generation control module is connected to the wind power generation control module. The output end of the generator is connected, the output end of the wind power generation control module is connected to the DC bus; the input end of the photovoltaic power generation control module is connected to the output end of the photovoltaic power generation component, and the The output terminal is connected to the DC bus; the main control module is connected to the wind power generation control module, and is used to convert the AC power output by the wind generator into a DC power matching the power parameters of the energy storage device, and The converted DC power is transmitted to the DC bus; the main control module is connected to the photovoltaic power generation control module, and is used to convert the DC power output by the photovoltaic power generation component into a power source parameter matching the energy storage device And deliver the converted DC power to the DC bus.

Optionally, the second power supply device is a diesel generator and a power grid.

Optionally, the wind power generation control module includes a wind turbine unloading circuit; the main control module is used to control the wind turbine unloading circuit when the output voltage of the wind generator is higher than a preset unloading voltage Unloading the wind power generator.

Optionally, the photovoltaic power generation control module includes a photovoltaic unloading circuit; the main control module is used to control the photovoltaic unloading circuit to control the photovoltaic unloading circuit when the voltage of the energy storage device reaches a preset float voltage The energy storage device performs floating charge.

Optionally, the bidirectional inverter control module includes a bidirectional inverter circuit, a three-phase isolation transformer, and an AC filter circuit, the AC filter circuit includes a first filter inductor and a filter capacitor, and the output terminal of the bidirectional inverter circuit is connected One end of the first filter inductor, the other end of the first filter inductor is connected to the input end of the three-phase isolation transformer, the output end of the three-phase isolation transformer is connected to the filter capacitor, and the filter capacitor is connected to the AC bus connection.

Optionally, the AC filter circuit further includes a second filter inductor, and the second filter inductor is connected between the three-phase isolation transformer and the filter capacitor.

Optionally, the AC filter circuit further includes a third filter inductor, and the third filter inductor is connected between the filter capacitor and the AC bus.

Optionally, the converter further includes a lightning protection module, which is respectively connected to the output terminal of the first power supply device and the output terminal of the second power supply device.

Optionally, the energy storage device is a battery pack, and the battery pack is connected in parallel to the DC bus.

Optionally, the energy storage device is connected to the DC bus through a soft start circuit.

In a second aspect, a method for controlling a converter is provided, the method is applied to the converter in the power system as described in the first aspect, the power system further includes a power grid, and the method includes:

After determining that the power system is successfully started, control the power system to operate in off-grid inverter mode; obtain the power parameters of the power grid; determine whether the power parameters of the power grid meet the grid connection conditions; if the power of the power grid When the parameters meet the grid-connected condition, the power system is controlled to operate in the grid-connected inverter mode.

Optionally, the power system further includes an energy storage device connected to the DC bus, and when the power system is operating in a grid-connected inverter mode, the method further includes: obtaining the storage device The voltage of the energy device; when the voltage of the energy storage device is lower than the preset initial charging voltage of the grid, the two-way inverter control module is controlled to convert the AC power on the AC bus into the DC power on the DC bus , So that the power system operates in grid charging mode.

Optionally, the power system further includes a diesel generator, a first power supply device, and a load, the diesel generator is connected to the AC bus, and the first power supply device is connected to the first power supply control module through the first power supply control module. The load is connected to the DC bus, and the method further includes: if the power parameter of the grid does not meet the grid connection condition, obtaining the output power of the first power supply device and the demand of the load Power; determine whether the output power of the first power supply device is less than the required power of the load; if the output power of the first power supply device is less than the required power of the load, start the diesel generator to generate electricity.

Optionally, after the diesel generator is started to generate electricity, the method further includes: when it is detected that the output power of the diesel generator is greater than the required power of the load, controlling the two-way inverter control module to control the AC The AC power on the bus is converted into the DC power on the DC bus, so that the power system operates in a diesel generator charging mode.

Optionally, when the power system is operating in grid-connected inverter mode or operating in off-grid inverter mode or operating in grid charging mode or operating in diesel generator charging mode, the method further includes: according to a preset The maximum power tracking algorithm controls the output power of the first power supply device through the first power supply control module to achieve maximum power point tracking control.

Optionally, the controlling the power system to operate in an off-grid inverter mode includes: controlling the two-way inverter control module to supply the AC bus at a preset voltage and frequency according to a preset frequency-voltage control algorithm AC output on the

Optionally, the controlling the power system to operate in a grid-connected inverter mode includes: according to a preset power control algorithm, controlling the two-way inverter control module to communicate to the AC according to preset active power and reactive power AC output on the bus.

Optionally, the power system further includes an energy storage device connected to the DC bus, and when the power system is operating in a grid-connected inverter mode, the method further includes: obtaining the storage device The voltage of the energy device; when the voltage of the energy storage device is lower than the preset grid-connected voltage, stop converting the DC power on the DC bus into the AC power on the AC bus through the bidirectional inverter module.

Optionally, the power system further includes an energy storage device connected to the DC bus, and when the power system is operating in an off-grid inverter mode, the method further includes: obtaining the storage device The voltage of the energy device; when the voltage of the energy storage device is lower than the preset minimum voltage, stop converting the DC power on the DC bus into the AC power on the AC bus through the bidirectional inverter module.

Optionally, the power system further includes a wind power generator, which is connected to the DC bus through the wind power generation control module, and is operated in grid-connected inverter mode or in off-grid inverter mode. When operating in variable mode or operating in grid charging mode or operating in diesel generator charging mode, the method further includes: obtaining the output voltage of the wind generator; when the output voltage of the wind generator is higher than a preset wind power When the generator unloads the voltage, the wind generator is unloaded through the wind turbine unloading circuit.

Optionally, the power system further includes a photovoltaic power generation component and an energy storage device, the photovoltaic power generation component is connected to the DC bus through the photovoltaic power generation control module, and the energy storage device is connected to the DC bus. When the power system is operating in grid-connected inverter mode or in off-grid inverter mode or in grid charging mode or in diesel generator charging mode, the method further includes: obtaining the voltage of the energy storage device; When the voltage of the energy storage device reaches the preset float voltage, the photovoltaic unloading circuit is controlled to enable the photovoltaic power generation component to float the energy storage device.

In a third aspect, a main control module is provided, the main control module is applied to the converter in the power system as described in the first aspect, the power system includes a power grid, and the main control module is specifically used In: After determining that the power system is successfully started, control the power system to operate in an off-grid inverter mode; obtain the power parameters of the power grid; determine whether the power parameters of the power grid meet the grid-connected conditions; if the power grid If the power parameters meet the grid-connected conditions, the power system is controlled to operate in grid-connected inverter mode.

The embodiment of the application provides a converter, which is applied to a power system. The power system includes a first power supply device, an energy storage device, a second power supply device, and a load. The converter includes: a first power supply control module, a two-way inverter Control module, main control module, DC bus and AC bus; among them: the input end of the first power supply control module is connected with the output end of the first power supply device, the output end of the first power supply control module is connected with the DC bus; the energy storage device is connected with DC bus connection; the DC side of the bidirectional inverter control module is connected to the DC bus, the AC side of the bidirectional control module is connected to the AC bus; the AC bus is connected to the load and the second power supply device; the main control module is connected to the first power supply control module, Used to convert the electric energy output by the first power supply device into direct current that matches the power parameters of the energy storage device, and transmit the converted direct current to the direct current bus; the main control module is connected to the bidirectional inverter control module for control The two-way inverter control module converts the AC power on the AC bus into DC power, and transmits the converted DC power to the DC bus, or controls the two-way inverter control module to convert the DC power on the DC bus into AC power, and convert the converted AC power Transported to the AC bus.

Compared with the prior art connection between the AC bus and the DC bus through a one-way DC/AC inverter circuit, only the DC power on the DC bus can be converted into AC power and transmitted to the AC bus. In this application, the AC bus and the DC The busbars are connected by a two-way inverter control module, which not only converts the DC power on the DC bus into AC power and transmits it to the AC bus, but also converts the AC power on the AC bus to DC power and transmits it to the DC bus for storage. The device can be charged in reverse. Moreover, in this application, the main control module can control the first power supply control module to convert the electrical energy output by the first power supply device into direct current that matches the power supply parameters of the energy storage device, and transmit the converted direct current to the direct current bus, so as to store The energy device does not need to be connected to the DC bus through a two-way DC/DC conversion circuit, which can save a two-way DC/DC conversion circuit; at the same time, the diesel generator and the grid share a two-way inverter control module to charge the battery in reverse, compared with traditional technical solutions The structure of Zhongdiesel generators connected to the DC bus through AC/DC is more simplified.

Of course, implementing any product or method of the present application does not necessarily need to achieve all the advantages described above at the same time.

Description of the drawings

In order to explain the embodiments of the present invention and the technical solutions of the prior art more clearly, the following briefly introduces the drawings that need to be used in the embodiments and the prior art. Obviously, the drawings in the following description are merely present For some of the embodiments of the invention, for those of ordinary skill in the art, other drawings may be obtained based on these drawings without creative work.

Figure 1 is a schematic structural diagram of a converter in the prior art;

FIG. 2 is a schematic structural diagram of a converter provided by an embodiment of the application;

FIG. 3 is a schematic structural diagram of a first power supply device provided by an embodiment of this application;

4 is a schematic structural diagram of a first power supply control module provided by an embodiment of the application;

FIG. 5 is a schematic structural diagram of a second power supply device provided by an embodiment of this application;

6 is a schematic structural diagram of an uncontrolled rectification wind power generation control module provided by an embodiment of the application;

Fig. 7 is a schematic structural diagram of a semi-controlled rectification wind power generation control module provided by an embodiment of the application;

FIG. 8 is a schematic structural diagram of a wind power generation control module with fully controlled rectification provided by an embodiment of the application;

FIG. 9 is a schematic structural diagram of a photovoltaic power generation control module provided by an embodiment of the application;

FIG. 10 is a schematic structural diagram of a bidirectional inverter control module provided by an embodiment of the application;

FIG. 11 is a schematic diagram of communication of a main control module provided by an embodiment of this application;

FIG. 12 is a schematic structural diagram of a soft start circuit provided by an embodiment of the application;

FIG. 13 is a flowchart of a method for controlling a converter according to an embodiment of the application;

FIG. 14 is a schematic diagram of a control structure of a converter during off-grid inverter operation according to an embodiment of the application;

15 is a schematic diagram of the control structure of a converter during grid-connected inverter operation provided by an embodiment of the application;

FIG. 16 is a flowchart of a method for controlling a converter according to an embodiment of the application.

detailed description

In order to make the objectives, technical solutions, and advantages of the present invention clearer and clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

As shown in Figure 2, an embodiment of the present application provides a converter, which is applied to a power system. The power system includes a first power supply device, an energy storage device, a second power supply device, and a load. The converter includes: Control module, bidirectional inverter control module, main control module, DC bus and AC bus, including:

The input end of the first power supply control module is connected to the output end of the first power supply device, the output end of the first power supply control module is connected to the DC bus; the energy storage device is connected to the DC bus; the DC side of the bidirectional inverter control module is connected to the DC bus Connected, the AC side of the bidirectional control module is connected to the AC bus; the AC bus is connected to the load and the second power supply device; the main control module is connected to the first power supply control module to convert the electrical energy output by the first power supply device into energy storage The DC power matching the power parameters of the device is transmitted to the DC bus; the main control module is connected with the bidirectional inverter control module to control the bidirectional inverter control module to convert the AC power on the AC bus into DC power. And transfer the converted DC power to the DC bus, or control the bidirectional inverter control module to convert the DC power on the DC bus into AC power, and transfer the converted AC power to the AC bus.

In the embodiment of the present application, the main control module can control the first power supply device to supply electrical energy, and the main control module can control the first power supply control module to convert the electrical energy output by the first power supply device into direct current that matches the power supply parameters of the energy storage device. And transfer the converted DC power to the DC bus. The main control module can control the bidirectional inverter control module to convert the DC power on the DC bus into AC power, and transmit the converted AC power to the AC bus to make the first power supply device Supply electrical energy to the load. In the case where the first power supply device has excess energy after supplying the load, that is, when P _S1- P _l >0, the first power supply device can charge the energy storage device through the DC bus. Among them, P _S1 is the active power output by the first power supply device, and P _l is the active power required by the load. The active power absorbed by the energy storage device is P _{B_in} = P _S1 -P _l . In the case where the electric energy supplied by the first power supply device does not meet the demand of the load, that is, when P _S- P _l <0, the energy storage device can output electric energy to the DC bus to supply electric energy to the load through the bidirectional inverter control module , To meet the needs of the load. The active power output by the energy storage device P _{B_out} = P _l- P _S1 .

Or, in the case that the power supplied by the first power supply device does not meet the demand of the load, that is, when P _S- P _l <0, the main control module may control the second power supply device to supply power to the load, and the main The control module can also control the two-way inverter control module to convert the AC power on the AC bus into DC power, and deliver the converted DC power to the DC bus, so that the second power supply device can charge the energy storage device. In this case, P _S2 =P _{B_in} +P _l -P _S1 . Among them, P _S2 is the active power output by the second power supply device.

In this way, in this application, the AC bus and the DC bus are connected by the bidirectional inverter control module, which can not only convert the DC power on the DC bus into AC power and transmit it to the AC bus, but also convert the AC power on the AC bus into DC power. It is sent to the DC bus to reversely charge the energy storage device. Moreover, in this application, the main control module can control the first power supply control module to convert the electrical energy output by the first power supply device into direct current that matches the power supply parameters of the energy storage device, and transmit the converted direct current to the direct current bus, so as to store The energy device does not need to be connected to the DC bus through a bidirectional DC/DC conversion circuit, and a bidirectional DC/DC conversion circuit can be saved, and the circuit structure of the converter is simplified.

Optionally, as shown in Figures 3 and 4, the first power supply device includes a wind generator and a photovoltaic power generation component, and the first power supply control module includes a wind power generation control module and a photovoltaic power generation control module, wherein:

The input end of the wind power generation control module is connected to the output end of the wind power generator, the output end of the wind power generation control module is connected to the DC bus; the input end of the photovoltaic power generation control module is connected to the output end of the photovoltaic power generation component, and the output of the photovoltaic power generation control module The main control module is connected to the wind power generation control module, and is used to convert the AC power output by the wind turbine into DC power matching the power parameters of the energy storage device, and transmit the converted DC power to the DC bus; The main control module is connected to the photovoltaic power generation control module, and is used to convert the direct current output from the photovoltaic power generation component into direct current that matches the power supply parameters of the energy storage device, and transmit the converted direct current to the DC bus.

Optionally, as shown in Figure 5, the second power supply device is a diesel generator and a power grid.

In the embodiment of the present application, the power grid can be connected to the AC bus through the first controlled switch, and the main control module can obtain the power parameters of the power grid. If the power parameters of the power grid meet the grid connection conditions, such as the power grid and the amplitude of the grid voltage, If the frequency and phase meet the grid-connected conditions, the main control module can control the first controlled switch to turn on to connect the grid to the AC bus; if the power parameters of the grid do not meet the grid-connected conditions, such as the grid has no electricity or a fault, the main control The module can control the first controlled switch to be turned on to disconnect the power grid from the AC bus.

In the case that the power grid is connected to the AC bus, if the electric energy supplied by the first power supply device meets the demand of the load, that is, P _S1 -P _l >0, the electric energy supplied by the first power supply device can also charge the energy storage device. When the active power absorbed by the device reaches the limit value P _{B_in_max} , that is, P _S1 -P _l -P _{B_in_max} > 0, the first power supply device can also input electric energy to the grid through the two-way inverter module, and the active power absorbed by the grid is P _{e_in} = P _S1 -P _l -P _{B_in_max} . If the electric energy supplied by the first power supply device cannot meet the demand of the load, that is, P _S1 -P _l <0, the grid can supply power to the load, and the main control module can also control the bidirectional inverter control module to convert the AC power on the AC bus into DC power. The converted DC power is delivered to the DC bus so that the grid can charge the energy storage device. At this time, the first power supply device also charges the energy storage device.

In the embodiment of the present application, when the power grid is disconnected from the AC bus, if the electric energy supplied by the first power supply device cannot meet the demand of the load, that is, P _S1 -P _l <0, the diesel generator can be started to generate electricity, so that The diesel generator supplies power to the load. When it is detected that the power output by the diesel generator meets the load and there is surplus power, the main control module can also control the bidirectional inverter control module to convert the AC power on the AC bus into DC power. The resulting direct current is delivered to the direct current bus so that the diesel generator can charge the energy storage device. At this time, the first power supply device also charges the energy storage device.

In this way, coordinated control between wind generators, photovoltaic power generation components, energy storage devices, diesel generators, and power supply sources of the power grid can be realized, and the process of switching between power sources can be reasonably optimized to ensure the continuous and stable power supply of the load.

Optionally, the wind power generation control module includes a wind turbine unloading circuit. When the output voltage of the wind generator is higher than the preset unloading voltage, the main control module can control the wind turbine unloading circuit to unload the wind generator.

As shown in FIG. 6, an embodiment of the present application provides a schematic structural diagram of a wind power generation control module. The wind power generation control module includes an uncontrolled rectifier circuit, a wind turbine unloading circuit, and a wind turbine boost circuit. The input end of the controlled rectification circuit is connected, the output end of the uncontrolled rectification circuit is connected to the input end of the fan unloading circuit through the capacitor C1, and the output end of the fan unloading circuit is connected to the input end of the fan booster circuit. The output terminal is connected to the DC bus. The uncontrolled rectifier circuit is used to convert the AC power output by the wind turbine into DC power, the wind turbine unloading circuit is used to unload the excess power output by the wind turbine, and the wind turbine booster circuit is used to rectify the DC power output by the wind turbine. It is converted into direct current that matches the voltage of the energy storage device.

Among them, the fan unloading circuit includes unloading resistor R1, diode VD3 and power switch tube VT4, unloading resistor R1 and diode VD3 are connected in parallel, and the positive output end of the fan rectifier circuit is connected to the cathode of diode VD3, and the anode of VD3 is connected to VT4. The source, the negative output terminal of the fan rectifier circuit is connected to the drain of VT4, the grid of VT4 is connected to the main control module, and the main control module controls the on and off of VT4. When VT4 is off, the unloading resistor R1 is not connected. When VT4 is on, the unloading resistor R1 is connected, which can unload the excess electric energy output by the wind turbine. In one embodiment, the diode VD3 is an anti-parallel diode of a power switch tube, and the power switch tube and the power switch tube VT4 are integrated in the same IGBT (Insulated Gate Bipolar Transistor, insulated gate bipolar transistor) module.

The main control module can obtain the output voltage of the wind turbine. When the output voltage of the wind turbine is higher than the preset unloading voltage, the main control module adopts the PWM (Pulse Width Modulation) control strategy, and adjusts the VT4 The duty cycle is used to adjust the time when the unloading resistor R1 is connected to unload the wind turbine. When the duty cycle of VT4 is 100%, the wind turbine is completely unloaded. Since the duty cycle can be varied from 0 to 100%, the adjustment accuracy of the unloading circuit is high. In this way, the wind generator is prevented from being damaged due to the excessively high output voltage of the wind generator.

As an example, the above-mentioned uncontrolled rectifier circuit can also be replaced with a half-controlled rectifier circuit or a fully-controlled rectifier circuit. The two structures are shown in Figs. 7 and 8 respectively.

Optionally, the photovoltaic power generation control module includes a photovoltaic unloading circuit. When the voltage of the energy storage device reaches the preset float voltage, the main control module can control the intermittent output current of the photovoltaic unloading circuit to float the energy storage device.

As shown in FIG. 9, an embodiment of the present application provides a schematic structural diagram of a photovoltaic power generation control module. The photovoltaic power generation control module includes a photovoltaic unloading circuit and a photovoltaic booster circuit. The output end of the photovoltaic power generation component is connected to the input end of the photovoltaic unloading circuit through the capacitor C2, the output end of the photovoltaic unloading circuit is connected to the input end of the photovoltaic booster circuit, and the output end of the photovoltaic booster circuit is connected to the DC bus. The photovoltaic unloading circuit is used to unload the photovoltaic power generation components, and the photovoltaic boost circuit is used to convert the direct current output by the photovoltaic unloading circuit into direct current that matches the voltage of the energy storage device.

Among them, the photovoltaic unloading circuit includes a power switch tube VT1 and a power switch tube VT2. The source of VT1 is connected to the positive electrode of the photovoltaic input, the drain of VT1 is connected to the source of VT2, and the drain of VT2 is connected to the negative electrode of the photovoltaic input. The two ends of the capacitor C2 are respectively connected to the positive and negative electrodes of the photovoltaic input, the drain of VT1 and the drain of VT2 are respectively connected to the two input terminals of the photovoltaic boost circuit, and the gates of VT1 and VT2 are respectively connected to the main control module.

In this embodiment of the application, the main control module can obtain the voltage of the energy storage device. When the voltage of the energy storage device is higher than the photovoltaic floating voltage, the main control module can control VT2 to be in the off state and control VTI to a certain duty cycle. Periodically turn on and off to achieve intermittent, low-current charging of the energy storage device to ensure that the voltage of the energy storage device is maintained within a certain range. In this way, it is avoided that the output voltage of the photovoltaic power generation component is too high to damage the photovoltaic power generation component, and the energy storage device can be floated.

It should be noted that in order to simplify the circuit structure and improve the reliability and stability of the system, in other embodiments, the photovoltaic unloading circuit can be omitted. However, when designing photovoltaic power generation components, it is necessary to ensure that the output voltage of the photovoltaic power generation components is the highest. Will exceed the battery overcharge protection voltage. At this time, directly controlling the photovoltaic boost circuit through the main control module can also realize the floating charge control of the energy storage device.

The embodiment of the application provides a bidirectional inverter control module, please refer to FIG. 10. The bidirectional inverter control module includes a bidirectional inverter circuit, a three-phase isolation transformer, and an AC filter circuit. The AC filter circuit includes a first filter inductor, a second filter inductor, a third filter inductor, and a filter capacitor. The input end of the first filter inductor is connected The output terminal of the bidirectional inverter circuit, the output terminal of the first filter inductor is connected to the three-phase isolation transformer, the output terminal of the three-phase isolation transformer is connected to the input terminal of the second filter inductor, and the output terminal of the second filter inductor is connected to the input terminal of the filter capacitor , The output end of the filter capacitor is connected to the input end of the third filter inductor, and the output end of the third filter inductor is connected to the AC bus. It should be noted that the second filter inductor and/or the parasitic inductance of the isolation transformer and the filter capacitor form an LC (inductance capacitor) filter circuit; the second filter inductor and/or the parasitic inductance of the isolation transformer and the filter capacitor and the third filter inductor LCL (inductance capacitance inductance) type filter circuit is formed. The second filter inductor is used to enhance the parasitic inductance of the three-phase isolation transformer. In other embodiments, the second filter inductor and/or the third filter inductor may also be omitted.

Please refer to FIG. 11, the main control module may acquire an input voltage and current of the photovoltaic _U PV_in booster circuit I _{PV_in,} the input voltage _U W_in fan and booster circuit current I _{W_in,} the energy storage device to access the DC link and the voltage _U Bat_in Current I _{Bat_in} , DC bus voltage U _{DC_link} , grid voltage U _grid and current I _grid , diesel generator voltage U _die and current I _grid , load voltage U _load and current I _load . The sensor samples the above data and inputs it to the main control module for calculation and processing. The main control module outputs 5 drive signals after processing, which are used to drive the photovoltaic unloading circuit, photovoltaic booster circuit, fan unloading circuit, fan booster circuit, and bidirectional Inverter circuit to control the on-off of switching devices in the corresponding circuit.

Optionally, the main control module may be a DSP (Digital Signal Processing, digital signal processing) chip, and the model of the DSP chip may be DSPIC33EP or DSPIC30F.

In the embodiment of the present application, the converter may include three lightning protection modules, and the three lightning protection modules are respectively connected to the output end of the photovoltaic power generation component, the output end of the wind generator, and the output end of the power grid.

Optionally, the energy storage device is a battery pack, which is connected in parallel to the DC bus.

As shown in FIG. 12, an embodiment of the present application provides a schematic structural diagram of a soft-start circuit. The soft-start circuit includes a DC contactor K1, an anti-reverse diode D2, and a soft-start resistor R2. The anti-reverse diode D2 and the soft-start resistor R2 are connected in series. Then it is connected in parallel with the DC contactor K1, and the positive terminal of the anti-reverse diode D2 is connected to the positive terminal of the energy storage device, and the negative terminal of the anti-reverse diode D2 is connected to the soft start resistor R2. The main control module can control the on and off of K1 to control the on and off of the DC bus and the energy storage device.

Optionally, a fuse F1 is also connected between the soft start circuit and the DC bus to protect the energy storage device in the event of a short circuit.

Optionally, the converter further includes a display module, which is connected to the main control module, and the display module is used to display power supply parameters of the power system and/or control parameters of the main control module.

Optionally, the converter also includes a brake switch for short-circuit braking of the wind generator, a circuit breaker for connecting to an energy storage device, a circuit breaker for connecting photovoltaic power generation components, a circuit breaker for connecting to the power grid, A contactor for connecting diesel generators. Among them, the brake switch used for short-circuit braking of the wind turbine, the circuit breaker connected to the energy storage device, the circuit breaker connected to the photovoltaic power generation component, and the circuit breaker connected to the power grid are all manually controlled. Control module control.

Based on the same technical concept, an embodiment of the present application also provides a method for controlling a converter, which is applied to the converter in the above-mentioned power system, and the power system also includes a power grid. As shown in Figure 13, the specific steps are as follows:

Step 1301, after determining that the power system is successfully started, control the power system to operate in an off-grid inverter mode.

In the example of this application, the power system can be initialized after it is powered on. After it is determined that the initialization is successful (that is, the power system is successfully started), the converter can control the power system to operate in off-grid inverter mode, that is, control the converter to be off-grid State and control the bidirectional inverter control module to convert the DC power on the DC bus into AC power, and transmit the converted AC power to the AC bus.

Optionally, the power system further includes an energy storage device, which is connected to the DC bus. When the power system is operating in an off-grid inverter mode, the steps of the above-mentioned converter control method further include: obtaining the voltage of the energy storage device; When the voltage of the energy storage device is lower than the preset minimum voltage, stop converting the DC power on the DC bus into the AC power on the AC bus through the bidirectional inverter module.

In this embodiment of the application, the converter further includes a detection component, which is used to detect the voltage of the energy storage device. When the power system is operating in off-grid inverter mode, the main control module can obtain the voltage of the energy storage device. The voltage of the energy device is lower than the preset minimum voltage. The main control module can control the bidirectional inverter module to stop converting the DC power on the DC bus into AC power on the AC bus. In this case, wind turbines and photovoltaic power generation components can pass The DC bus provides power to the energy storage device.

Optionally, the specific process of controlling the power system to operate in the off-grid inverter mode may be: according to a preset frequency-voltage control algorithm, controlling the two-way inverter control module to transfer to the AC bus output AC power.

In the embodiment of the present application, the main control module can control the bidirectional inverter control module to output according to the preset voltage and frequency according to the preset frequency-voltage control algorithm, that is, control the bidirectional inverter control module in the voltage and current double closed loop mode (ie Constant voltage and constant frequency mode) operation. Refer to Figure 14, which is a schematic diagram of the control structure of the converter during off-grid inverter operation. The main control module obtains the angular frequency ω of the output voltage u _a , u _b and u _c of the bidirectional inverter control module through PLL (Phase Locked Loop), and the main control module calculates the angle between 2πf _ref and the output voltage of the inverter control module The difference between the frequency ω, and the calculated difference is calculated by the integral link to obtain the phase angle θ. Among them, f _ref is a preset reference frequency, which can be 50 Hz. The main control module determines the voltage components u _dref and u _{qref of the} reference voltage u _ref in the dq coordinate system according to the preset reference voltage u _ref , the phase angle θ and formula (1). , Where the dq coordinate system is the coordinate system after Park transformation.

The main control module may control based on the calculated phase angle θ of the inverter output current bidirectional conversion module i _a, i _b, i _c into the dq axis current component i _D coordinate system and i _q, the main control module may calculate The output phase angle θ converts the output voltages u _a , u _b and u _{c of the} bidirectional inverter module into voltage components u _d and u _q in the dq axis coordinate system. The main control module can _calculate the difference between u _dref and u _d , and the difference between u _qref and u _q through PI to obtain the current reference value of the inner loop control:

Among them, i _dref and i _qref are the current reference values of the inner loop control, u _dref and u _qref are the reference values of the output voltage of the bidirectional inverter control module, u _ref is the voltage component in the dq coordinate system, and u _d and u _q are bidirectional The voltage component of the actual output voltage of the inverter module in the dq axis coordinate system.

The main control module can perform PI calculation on the difference between i _dref and i _d , and superimpose the result of the calculation with u _d and the product of i _q and ωL to obtain u _sd , where ω is the output voltage of the bidirectional inverter module Angular frequency, L is the filter inductance. The main control module can perform PI operation on the difference between i _qref and i _q , and superimpose the result of the operation with u _q and the product of i _d and ωL to obtain u _sq , where ω is the output voltage of the bidirectional inverter module Angular frequency, L is the filter inductance. The main control module can convert u _sd and u _sq into voltage signals in the abc coordinate system (ie, three-phase coordinate system) according to the calculated phase angle θ, and perform SPWM (Sinusoidal Pulse Width Modulation) on the converted voltage signal. Pulse Width Modulation) to obtain the control signal PWM (Pulse Width Modulation) signal of the bidirectional inverter module, and transmit the PWM signal to the bidirectional inverter control module. In this way, the frequency and voltage of the output voltage of the bidirectional inverter control module can be adjusted to the preset reference frequency f _ref and reference voltage u _{ref respectively} . The bidirectional inverter control module can set the reference frequency f _ref and the reference voltage u _{ref as required} .

Step 1302: Obtain power parameters of the power grid.

Among them, the power parameters can include the amplitude, frequency and phase of the grid voltage.

In the embodiment of the present application, the converter further includes a detection component, which is used to detect power parameters of the power grid, and send the power parameters to the main control module, and the main control module can obtain the power parameters of the power grid.

Step 1303: It is judged whether the power parameters of the power grid meet the grid connection conditions.

In the embodiment of the present application, the main control module can determine whether the power parameters of the power grid match the power parameters of the AC bus. If the power parameters of the power grid match the power parameters of the AC bus, it is determined that the power parameters of the power grid meet the grid connection Condition: If the power parameters of the power grid do not match the power parameters of the AC bus, it is determined that the power parameters of the power grid do not meet the grid connection conditions.

Step 1304: If the power parameters of the grid meet the grid-connected conditions, control the power system to operate in a grid-connected inverter mode.

In the embodiment of this application, if the power parameters of the grid meet the grid-connected conditions, the converter can control the power system to operate in grid-connected inverter mode, that is, the main control module can control the AC bus to connect to the grid so that the power system is in parallel. Grid status and control the bidirectional inverter control module to convert the DC power on the DC bus into AC power, and transmit the converted AC power to the AC bus.

Optionally, the specific process of controlling the power system to operate in grid-connected inverter mode can be: according to a preset power control algorithm, controlling the bidirectional inverter control module to output to the AC bus according to preset active power and reactive power Alternating current.

In the embodiment of the present application, in the grid-connected inverter mode, the main control module controls the bidirectional inverter control module to output according to preset active power and reactive power according to a preset power control algorithm. Referring to Figure 15, the main control module obtains the phase angle θ of the grid voltage through the PLL, and the main control module can convert the output current of the bidirectional inverter into the current components i _d and i in the dq axis coordinate system according to the phase angle θ of the grid voltage. _q , the main control module can convert the grid voltage into current components e _d and e _q in the dq axis coordinate system according to the phase angle θ of the grid voltage. The main control module can compare the preset reference voltage U ^* _DC with the DC bus side voltage Perform PI calculation on the difference of U _DC to obtain the reference value i _{dref of} i _d . The main control module can perform PI calculation on the difference between i _dref and i _d , and compare the result of the calculation with e _d , and i _q and ωL The products are superimposed to obtain v _d , where ω is the angular frequency of the power grid and L is the filter inductance. The main control module may be preset reference value i _q and i _q i _qref difference executing PI calculation, and the calculation result of the superposition of e _q, and the product _D i and ωL obtain v _q, where, [omega] Is the angular frequency of the grid, and L is the filter inductance. The main control module can convert v _d and v _q into a voltage signal in the abc coordinate system according to the phase θ of the grid voltage, and perform SPWM modulation on the converted voltage signal to obtain a PWM signal, and send the PWM signal to the bidirectional inverter control Module to adjust the active power and reactive power output by the bidirectional inverter control module. The main control module can adjust the active power and reactive power output by the bidirectional inverter control module by adjusting the preset values of U ^* _DC and i _dref , so as to realize the bidirectional inverter control module according to the preset active power and reactive power Output. When i _qref = 0, the bidirectional inverter control module only outputs active power and runs at unity power factor.

Among them, the principle of controlling the inverter control module according to the preset active power and reactive power output is as follows:

The state equation of the bidirectional inverter circuit is:

_{_{Wherein, u a, u b, u}} c is a bidirectional inverter circuit output _{_{voltage, i a, i b, i}} c is a bidirectional inverter circuit output _{_{current, e a, e b, e}} c of the grid voltage, L is the filter Inductance, R is the line resistance. Perform abc/dq transformation on formula (3) to obtain the mathematical model of the bidirectional inverter circuit in the dq coordinate system:

In the formula, e _d and e _q are the voltage components of the grid voltage in the dq axis coordinate system, ω is the grid voltage angular frequency, s is the differential operator, and the output current of the i _d and i _q bidirectional inverters are in the dq axis coordinate The current components under the system, u _d and u _q are the voltage components of the output voltage of the bidirectional inverter module in the dq axis coordinate system.

The governing equations of v _d and v _q are as follows:

In the formula, K _p and K _i are the proportional and integral adjustment coefficients respectively, and i _dref and i _qref are the reference values of the active and reactive currents i _d and i _q respectively.

According to the theory of instantaneous power, the instantaneous active and reactive power output by the bidirectional inverter control module are:

Among them, p is the active power output by the bidirectional inverter control module, and q is the reactive power output by the bidirectional inverter control module.

Since the dq coordinate system is a synchronous rotating coordinate system based on the grid voltage vector orientation, e _q =0. Equation (6) can be simplified as:

It can be seen from equation (7) that when the grid voltage is constant, controlling i _d and i _q can respectively control the active and reactive power of the bidirectional inverter control module. Therefore, the main control module can adjust i _d and i _q by adjusting the preset values of U ^* _DC and i _dref , and then adjust the active power and reactive power output by the bidirectional inverter control module.

Optionally, the power system further includes an energy storage device, which is connected to the DC bus. When the power system is operating in the grid-connected inverter mode, the control method steps of the above-mentioned converter further include: obtaining the voltage of the energy storage device; When the voltage of the energy storage device is lower than the preset grid-connected voltage, stop converting the DC power on the DC bus into the AC power on the AC bus through the bidirectional inverter module.

In the embodiment of the application, the converter further includes a detection component, which is used to detect the voltage of the energy storage device. When the power system is operating in the grid-connected inverter mode, the main control module can obtain the voltage of the energy storage device. When the voltage of the energy device is lower than the preset grid-connected voltage, the main control module can control the bidirectional inverter module to stop converting the DC power on the DC bus into AC power on the AC bus. In this case, the grid supplies power to the load. The power supply device charges the energy storage device through the DC bus.

Optionally, the power system further includes an energy storage device, which is connected to the DC bus. When the power system is operating in the grid-connected inverter mode, the control method steps of the above-mentioned converter further include: obtaining the voltage of the energy storage device; When the voltage of the energy storage device is lower than the preset initial charging voltage of the grid, the AC power on the AC bus is converted into the DC power on the DC bus through the bidirectional inverter control module to make the power system operate in the grid charging mode.

Among them, the initial charging voltage of the grid is lower than the grid-connected voltage.

In this embodiment of the application, when the power system is operating in grid-connected mode, the main control module can obtain the voltage of the energy storage device. When the voltage of the energy storage device is lower than the preset initial charging voltage of the grid, the main control module can control The bidirectional inverter control module converts the AC power on the AC bus into the DC power on the DC bus to make the power system operate in grid charging mode, that is, the grid supplies power to the load, and the grid charges the energy storage device through the bidirectional inverter module, and the wind power The generator and photovoltaic power generation components charge the energy storage device.

Optionally, the power system further includes a diesel generator, a first power supply device and a load. The diesel generator is connected to the AC bus. The first power supply device is connected to the DC bus through the first power supply control module. The load is connected to the DC bus. If the power parameters of the above-mentioned converter do not meet the grid connection conditions, the steps of the above-mentioned converter control method further include: obtaining the output power of the first power supply device and the required power of the load; determining whether the output power of the first power supply device is less than the required power of the load; if If the output power of the first power supply device is less than the required power of the load, the diesel generator is started to generate electricity.

Wherein, the first power supply device may include a wind generator and a photovoltaic power generation component.

In the embodiment of this application, if the power parameters of the grid do not meet the grid connection conditions and the power system is operating in off-grid inverter mode, the detection component can detect the output voltage and output current of the wind turbine, and the output voltage and output of the photovoltaic power generation component. The current, and the voltage and current of the load, and the detected output voltage and output current of the wind turbine, the output voltage and output current of the photovoltaic power generation module, and the load voltage and current are sent to the main control module. The main control module can be based on the wind The output voltage and output current of the generator determine the output power of the wind generator, the output power of the photovoltaic power generation component is determined according to the output voltage and output current of the photovoltaic power generation component, and the required power of the load is determined according to the voltage and current of the load. When the sum of the output power of the wind generator and the photovoltaic power generation component is less than the required power of the load, the diesel generator can be started to generate electricity. Among them, the diesel generator can be started manually.

Optionally, when it is detected that the output power of the diesel generator is greater than the required power of the load, the main control module can control the bidirectional inverter control module to convert the AC power on the AC bus into DC power on the DC bus, so that the power system is in diesel The generator charging mode runs. In this case, the diesel generator supplies power to the load and charges the energy storage device through the two-way inverter module. The wind generator and photovoltaic power generation components charge the energy storage device through the DC bus.

Optionally, the power system also includes a wind generator, which is connected to the DC bus through a wind power generation control module, and is operated in grid-connected inverter mode or in off-grid inverter mode or in grid charging mode or When operating in the charging mode of the diesel generator, the steps of the above-mentioned converter control method further include: obtaining the output voltage of the wind generator; when the output voltage of the wind generator is higher than the preset unloading voltage of the wind generator, passing the wind turbine The unloading circuit unloads the wind turbine.

In the embodiment of the present application, the detection component can detect the output voltage of the wind generator, and send the detected output voltage of the wind generator to the main control module, and the main control module can obtain the output voltage of the wind generator; When the output voltage is higher than the preset unloading voltage of the wind turbine, the main control module controls the unloading circuit of the wind turbine to unload the wind turbine.

Optionally, the power system further includes a photovoltaic power generation component and an energy storage device, the photovoltaic power generation component is connected to the DC bus through the photovoltaic power generation control module, the energy storage device is connected to the DC bus, and the power system is in grid-connected inverter mode operation or When operating in off-grid inverter mode or operating in grid charging mode or operating in diesel generator charging mode, the steps of the above-mentioned converter control method further include: obtaining the voltage of the energy storage device; when the voltage of the energy storage device reaches a preset value During the floating charge voltage, the photovoltaic unloading circuit is controlled to enable the photovoltaic power generation component to float the energy storage device.

In the embodiment of the present application, the detection component can detect the output voltage of the photovoltaic power generation component, and send the detected output voltage of the photovoltaic power generation component to the main control module, and the main control module can obtain the output voltage of the photovoltaic power generation component; When the output voltage is higher than the preset float voltage, the main control module controls the photovoltaic unloading circuit to make the photovoltaic power generation component float the energy storage device.

Optionally, when the power system is operating in grid-connected inverter mode or operating in off-grid inverter mode or operating in grid charging mode or operating in diesel generator charging mode, the control method steps of the above converter further include: The preset maximum power tracking algorithm controls the output power of the first power supply device through the first power supply control module to achieve maximum power point tracking control.

In the embodiment of the present application, the main control module controls the output power of the first power supply control module according to a preset power tracking control algorithm, so as to realize the maximum power point tracking control. Refer to Figure 15, the main control module can determine when the photovoltaic power generation module is working at the maximum power point according to the DC voltage U _PV , current I _PV and MPPT (Maximum Power Point Tracking) algorithm output by the photovoltaic power generation module. The voltage U ^* _PV output by the photovoltaic power generation module is calculated by PI (Proportional Integral) and the difference between U ^* _PV and U _PV is sent to the PWM pulse generator. The PWM pulse generator outputs the control signal SI _PV and will The control signal SI _{PV is} sent to the gate control terminal of the switching device in the photovoltaic boost circuit to adjust the output power of the photovoltaic power generation component so that the output power of the photovoltaic power generation component is at the maximum power point, and the maximum power tracking of the photovoltaic power generation component is realized.

The main control module can obtain the actual output power P of the wind generator according to the AC voltage U _W and the AC current I _W output by the wind generator, and then obtain the speed of the wind generator in the current working state according to the preset speed-power curve ω corresponds to the maximum output power of the wind turbine P ^* , where the speed-power curve records the correspondence between the speed of the wind turbine and the maximum output power of the wind turbine, and the difference between P and P ^* is calculated by PI , Sent to the PWM pulse generator, the PWM pulse generator outputs the control signal SI _W , and sends the control signal SI _W to the gate control end of the switching device in the wind power boost circuit to adjust the output power of the wind generator to make the wind power The output power of the generator is located at the maximum power point, realizing the maximum power tracking of the wind generator.

The embodiment of the present application also provides an example of a converter control method, as shown in FIG. 16, the specific steps are as follows:

In step 1601, initialization is performed after the power system is powered on.

Step 1602: After determining that the power system is successfully started, control the power system to operate in an off-grid inverter mode.

Step 1603: Obtain power parameters of the power grid.

Step 1604: Determine whether the power parameters of the power grid meet the grid connection conditions;

If yes, go to step 1605; if not, go to step 1609.

Step 1605: Control the power system to operate in grid-connected inverter mode.

Step 1606: Obtain the voltage of the energy storage device.

Step 1607: Determine whether the voltage of the energy storage device is lower than the preset initial charging voltage of the grid.

If yes, go to step 1608; if not, go to step 1605.

Step 1608: Control the power system to operate in the grid charging mode.

Step 1609: Detect the output power of the first power supply device;

Step 1610: Determine whether the output power of the first power supply device is less than the required power of the load.

If yes, go to step 1611; if not, go to step 1602.

Step 1611, start the diesel generator to generate electricity.

Step 1612: When the output power of the diesel generator is greater than the required power of the load, control the power system to operate in the diesel generator charging mode.

Based on the same technical concept, the embodiments of the present application also provide a main control module. The main control module is applied to the converter in the above-mentioned power system. The power system includes the power grid, and the main control module is specifically used for:

After determining that the power system is successfully started, control the power system to operate in an off-grid inverter mode;

Obtaining power parameters of the power grid;

Judging whether the power parameters of the grid meet the grid connection conditions;

If the power parameters of the grid meet the grid-connected conditions, control the power system to operate in a grid-connected inverter mode.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the present invention Within the scope of protection.

Claims

A converter, applied to a power system, characterized in that the power system includes a first power supply device, an energy storage device, a second power supply device and a load, and the converter includes: a first power supply control module, a two-way Inverter control module, main control module, DC bus and AC bus; among them:

The input terminal of the first power supply control module is connected with the output terminal of the first power supply device, and the output terminal of the first power supply control module is connected with the DC bus;

The energy storage device is connected to the DC bus;

The DC side of the bidirectional inverter control module is connected to the DC bus, and the AC side of the bidirectional control module is connected to the AC bus;

The AC bus is connected to the load and the second power supply device;

The main control module is connected to the first power supply control module, and is used to convert the electrical energy output by the first power supply device into a direct current that matches the power supply parameters of the energy storage device, and to transmit the converted direct current To the DC bus;

The main control module is connected to the two-way inverter control module, and is used to control the two-way inverter control module to convert the AC power on the AC bus into DC power, and transmit the converted DC power to the DC bus , Or control the bidirectional inverter control module to convert the direct current on the direct current bus into alternating current, and transmit the converted alternating current to the alternating current bus.
The converter according to claim 1, wherein the first power supply device includes a wind generator and a photovoltaic power generation component;

The first power supply control module includes a wind power generation control module and a photovoltaic power generation control module;

The input end of the wind power generation control module is connected to the output end of the wind power generator, and the output end of the wind power generation control module is connected to the DC bus;

The input end of the photovoltaic power generation control module is connected to the output end of the photovoltaic power generation component, and the output end of the photovoltaic power generation control module is connected to the DC bus;

The main control module is connected to the wind power generation control module, and is used to convert the AC power output by the wind generator into a DC power matching the power parameters of the energy storage device, and transmit the converted DC power to the DC bus;

The main control module is connected to the photovoltaic power generation control module, and is used to convert the direct current output from the photovoltaic power generation component into direct current that matches the power supply parameters of the energy storage device, and transmit the converted direct current to the DC bus.
The converter according to claim 1, wherein the second power supply device is a diesel generator and a power grid.
The converter according to claim 2, wherein the wind power generation control module comprises a wind turbine unloading circuit;

The main control module is used to control the wind turbine unloading circuit to unload the wind turbine when the output voltage of the wind turbine is higher than a preset unloading voltage.
The converter according to claim 2, wherein the photovoltaic power generation control module comprises a photovoltaic unloading circuit;

The main control module is used to control the photovoltaic unloading circuit to float the energy storage device when the voltage of the energy storage device reaches a preset float voltage.
The converter according to claim 1, wherein the bidirectional inverter control module includes a bidirectional inverter circuit, a three-phase isolation transformer, and an AC filter circuit, and the AC filter circuit includes a first filter inductor and a filter capacitor , The output end of the bidirectional inverter circuit is connected to one end of the first filter inductor, the other end of the first filter inductor is connected to the input end of the three-phase isolation transformer, and the output end of the three-phase isolation transformer is connected to the The filter capacitor is connected to the AC bus.
The converter according to claim 6, wherein the AC filter circuit further comprises a second filter inductor, and the second filter inductor is connected between the three-phase isolation transformer and the filter capacitor.
The converter according to claim 6 or 7, wherein the AC filter circuit further comprises a third filter inductor, and the third filter inductor is connected between the filter capacitor and the AC bus.
The converter according to claim 1, wherein the converter further comprises a lightning protection module, and the lightning protection module is respectively connected to the output terminal of the first power supply device and the second power supply device. The output terminal is connected.
The converter according to claim 1, wherein the energy storage device is a battery pack, and the battery pack is connected in parallel to the DC bus.
The converter according to claim 1, wherein the energy storage device is connected to the DC bus through a soft start circuit.
A method for controlling a converter, wherein the method is applied to the converter in the power system according to any one of claims 1 to 11, the power system further includes a power grid, and the method includes :

After determining that the power system is successfully started, control the power system to operate in an off-grid inverter mode;

Obtaining power parameters of the power grid;

Judging whether the power parameters of the grid meet the grid connection conditions;

If the power parameters of the grid meet the grid-connected conditions, control the power system to operate in a grid-connected inverter mode.
The method according to claim 12, wherein the power system further comprises an energy storage device, the energy storage device is connected to the DC bus, and when the power system is operating in the grid-connected inverter mode, The method also includes:

Obtaining the voltage of the energy storage device;

When the voltage of the energy storage device is lower than the preset initial charging voltage of the grid, the bidirectional inverter control module is controlled to convert the AC power on the AC bus into the DC power on the DC bus, so that the The power system is operating in grid charging mode.
The method according to claim 12, wherein the power system further comprises a diesel generator, a first power supply device and a load, the diesel generator is connected to the AC bus, and the first power supply device passes through the The first power supply control module is connected to the DC bus, and the load is connected to the DC bus. The method further includes:

If the power parameters of the power grid do not meet the grid connection conditions, obtaining the output power of the first power supply device and the required power of the load;

Judging whether the output power of the first power supply device is less than the required power of the load;

If the output power of the first power supply device is less than the required power of the load, the diesel generator is started to generate electricity.
The method according to claim 14, characterized in that, after starting the diesel generator to generate electricity, the method further comprises:

When it is detected that the output power of the diesel generator is greater than the required power of the load, the two-way inverter control module is controlled to convert the AC power on the AC bus into the DC power on the DC bus, so that the The power system is operating in diesel generator charging mode.
The method according to any one of claims 12-15, wherein the power system is operating in grid-connected inverter mode or in off-grid inverter mode or in grid charging mode or in diesel generator charging mode At runtime, the method further includes:

According to a preset maximum power tracking algorithm, the output power of the first power supply device is controlled by the first power supply control module to achieve maximum power point tracking control.
The method according to claim 12, wherein the controlling the power system to operate in an off-grid inverter mode comprises:

According to a preset frequency-voltage control algorithm, the bidirectional inverter control module is controlled to output AC power to the AC bus at a preset voltage and frequency.
The method according to claim 12, wherein the controlling the power system to operate in a grid-connected inverter mode comprises:

According to a preset power control algorithm, the two-way inverter control module is controlled to output AC power to the AC bus according to preset active power and reactive power.
The method according to claim 12, wherein the power system further comprises an energy storage device, the energy storage device is connected to the DC bus, and when the power system is operating in the grid-connected inverter mode, The method also includes:

Obtaining the voltage of the energy storage device;

When the voltage of the energy storage device is lower than the preset grid-connected voltage, stop converting the direct current on the direct current bus into the alternating current on the alternating current bus through the bidirectional inverter module.
The method according to claim 12, wherein the power system further comprises an energy storage device connected to the DC bus, and when the power system is operating in an off-grid inverter mode, The method also includes:

Obtaining the voltage of the energy storage device;

When the voltage of the energy storage device is lower than the preset minimum voltage, stop converting the DC power on the DC bus into the AC power on the AC bus through the bidirectional inverter module.
The method according to any one of claims 12-15, wherein the power system further comprises a wind generator, the wind generator is connected to the DC bus through the wind power generation control module, and the power When the system is operating in grid-connected inverter mode or in off-grid inverter mode or in grid charging mode or in diesel generator charging mode, the method further includes:

Obtaining the output voltage of the wind generator;

When the output voltage of the wind generator is higher than the preset unloading voltage of the wind generator, the wind generator is unloaded through the wind turbine unloading circuit.
The method according to any one of claims 12-15, wherein the power system further comprises a photovoltaic power generation component and an energy storage device, the photovoltaic power generation component is connected to the DC bus through the photovoltaic power generation control module, The energy storage device is connected to the DC bus, and when the power system is operating in grid-connected inverter mode or in off-grid inverter mode or in grid charging mode or in diesel generator charging mode, Methods also include:

Obtaining the voltage of the energy storage device;

When the voltage of the energy storage device reaches the preset float voltage, the photovoltaic unloading circuit is controlled to enable the photovoltaic power generation component to float the energy storage device.
A main control module, wherein the main control module is applied to the converter in the power system according to any one of claims 1 to 11, the power system includes a power grid, and the main control module, Specifically used for:

After determining that the power system is successfully started, control the power system to operate in an off-grid inverter mode;

Obtaining power parameters of the power grid;

Judging whether the power parameters of the grid meet the grid connection conditions;

If the power parameters of the grid meet the grid-connected conditions, control the power system to operate in a grid-connected inverter mode.