Electric energy conversion method and system based on alternating current and direct current hybrid power distribution network

Abstract

The invention relates to an AC-DC hybrid power distribution network-based electric energy conversion method and system, the output end of a high-voltage rectification unit of a high-voltage module is connected in parallel with a high-voltage DC unit, a high-voltage inversion unit and a photovoltaic energy unit, and the high-voltage inversion unit is connected with a high-voltage AC unit; the access end of the low-voltage rectification unit of the low-voltage module is connected with an energy storage unit; the output end of the low-voltage rectification unit is connected with a transformer unit used for being connected with the access end of the high-voltage rectification unit. The new energy vehicle charging unit of the low-voltage module is connected with the transformer unit; the exchange control device is used for controlling the operation of the energy storage unit, the low-voltage rectification unit, the high-voltage rectification unit and the high-voltage inversion unit according to exchange requirements so as to convert electric energy; the structure of the formed new exchange system can convert the electric energy of photovoltaic power generation, the electric energy of vehicle charging, the electric energy stored in peak and valley and the electric energy of high-voltage alternating current and direct current in an interconnected exchanger according to needs, and the conversion and utilization rate of the electric energy is improved.

Description

Technical Field

[0001] The present application relates to the technical field of power distribution networks, and in particular to a method and system for converting electric energy based on an AC / DC hybrid distribution network. Background Art

[0002] With the increasing diversity of power sources within distribution networks, the increasing number of load types and demand, and the increasing complexity of multi-distribution network topologies, traditional energy management methods are no longer suitable for existing multi-distribution network energy optimization systems. Therefore, the AC / DC hybrid distribution network system, a complex energy system that integrates multiple types of power generation units, power consumption units, and storage power sources, is being developed to address these issues.

[0003] A hybrid AC / DC distribution network system includes switches that interchange DC and AC, switches that exchange DC with energy storage systems, and switches that exchange AC with energy storage systems. Ultimately, this system is AC-based, DC-assisted, and uses energy storage during off-peak hours to meet power distribution needs. Existing combinations of multiple switches result in high losses and a large number of links during the exchange process, depending on the voltage level and type of each distribution network. Furthermore, the coordinated use of multiple switches increases operational costs. Therefore, a new hybrid AC / DC switch structure is needed to meet the power conversion needs of hybrid AC / DC distribution networks. Summary of the Invention

[0004] The embodiments of the present application provide an electric energy conversion method and system based on an AC / DC hybrid distribution network to solve the problem in the related art that the combination of multiple switches results in large losses and a large number of links during the exchange process of the voltage levels and types of each distribution network, as well as increased usage costs.

[0005] In a first aspect, an electric energy conversion system based on an AC / DC hybrid distribution network is provided, comprising:

[0006] The high-voltage module includes a high-voltage rectifier unit, the output end of which is connected in parallel to a high-voltage DC unit, a high-voltage inverter unit, and a photovoltaic unit, and the high-voltage inverter unit is connected to a high-voltage AC unit; the high-voltage DC unit is used to control the on / off of the high-voltage rectifier unit and the high-voltage DC bus, the high-voltage AC unit is used to control the on / off of the high-voltage rectifier unit and the high-voltage AC bus; the photovoltaic unit is used to control the on / off of the high-voltage rectifier unit and the photovoltaic power generation device;

[0007] The low-voltage module includes a low-voltage rectifier unit and a new energy vehicle charging unit. The access end of the low-voltage rectifier unit is connected to an energy storage unit, which is used to store and release peak and valley electricity from the power station. The output end of the low-voltage rectifier unit is connected to a transformer unit for connecting to the access end of the high-voltage rectifier unit. The new energy vehicle charging unit is connected to the transformer unit.

[0008] The switching control device is connected to the energy storage unit, low-voltage rectifier unit, photovoltaic unit, high-voltage rectifier unit and high-voltage inverter unit, and is used to control the operation of the energy storage unit, low-voltage rectifier unit, high-voltage rectifier unit and high-voltage inverter unit according to the switching demand.

[0009] In some preferred implementations, the low-voltage rectifier unit includes a first capacitor connected in parallel with the energy storage unit, a low-voltage DC load, and a first H-bridge rectifier circuit;

[0010] The high-voltage rectifier unit includes a second capacitor connected in parallel with the high-voltage DC unit, a high-voltage DC load, and a second H-bridge rectifier circuit;

[0011] The high-voltage inverter unit includes a third capacitor and an H-bridge inverter circuit connected in parallel with the high-voltage AC unit.

[0012] In some preferred implementations, the first H-bridge rectifier circuit, the second H-bridge rectifier circuit and the H-bridge inverter circuit each include four MOS tube switches and four diodes; wherein each MOS tube corresponds to a diode to form four control components; the four control components are connected to form an H-bridge circuit.

[0013] In a second aspect, a method for converting electric energy based on an AC / DC hybrid distribution network is provided, which is applied to the electric energy conversion system, and comprises the following steps:

[0014] Obtaining a corresponding target control mode based on the switching demand, and then using the switching control device to control the energy storage unit, low-voltage rectifier unit, photovoltaic unit, high-voltage rectifier unit and high-voltage inverter unit according to the target control mode;

[0015] The control strategies of the first H-bridge rectifier circuit and the second H-bridge rectifier circuit include: control strategy one, in one cycle, the two control components of the upper half bridge and the two control components of the lower half bridge are respectively turned on;

[0016] The control strategy of the H-bridge inverter circuit includes: control strategy 2, in which within one cycle, one control component in the upper half bridge and one control component in the lower half bridge are turned on for a period of time, and another control component in the upper half bridge and another control component in the lower half bridge are turned on for another period of time.

[0017] In some preferred implementations, when the exchange requirement is to store the electric energy generated by the photovoltaic power generation device, the target control mode is:

[0018] The photovoltaic energy unit is controlled to be connected to the photovoltaic power generation device, the high-voltage rectifier unit is disconnected from the high-voltage DC bus, and the high-voltage rectifier unit is disconnected from the high-voltage AC bus; then the first H-bridge rectifier circuit and the second H-bridge rectifier circuit are controlled to execute control strategy one; control strategy one is that the two control components of the upper half bridge and the two control components of the lower half board are respectively turned on for a first time and a second time within one cycle; the control components of the H-bridge inverter circuit are all turned off to store the electric energy generated by the photovoltaic power generation device in the storage station.

[0019] In some preferred implementations, when the exchange demand is to use the electric energy generated by the photovoltaic power generation device as the electric energy required by the new energy vehicle charging unit, the target control mode is:

[0020] Control the photovoltaic energy unit to be connected with the photovoltaic power generation device, disconnect the high-voltage rectifier unit from the high-voltage DC bus, and disconnect the high-voltage rectifier unit from the high-voltage AC bus; control the control components of the first H-bridge rectifier circuit and the H-bridge inverter circuit to be completely turned off, and the second H-bridge rectifier circuit to execute control strategy one; control strategy one is that the two control components of the upper half bridge and the two control components of the lower half board are respectively turned on for the first time and the second time within one cycle, so that the electric energy generated by the photovoltaic power generation device is transmitted to the new energy vehicle charging unit after rectification.

[0021] In some preferred implementations, when the exchange requirement is to store the electric energy of the high-voltage DC bus, the target control mode is:

[0022] The high-voltage rectifier unit is controlled to be connected to the high-voltage DC bus, the photovoltaic energy unit is disconnected from the photovoltaic power generation, and the high-voltage rectifier unit is disconnected from the high-voltage AC bus; then the first H-bridge rectifier circuit and the second H-bridge rectifier circuit are controlled to execute control strategy one; control strategy one is that the two control components of the upper half bridge and the two control components of the lower half board are respectively turned on for a first time and a second time within one cycle, and the control components of the H-bridge inverter circuit are all turned off, so that the electric energy of the high-voltage DC bus is stored in the storage station.

[0023] In some preferred implementations, when the exchange requirement is to use the electric energy of the high-voltage DC bus as the electric energy required by the new energy vehicle charging unit, the target control mode is:

[0024] Control the high-voltage rectifier unit and the high-voltage DC bus to be connected, the photovoltaic energy unit to be disconnected from the photovoltaic power generation, and the high-voltage rectifier unit to be disconnected from the high-voltage AC bus; then control the control components of the first H-bridge rectifier circuit and the H-bridge inverter circuit to be all turned off, and the second H-bridge rectifier circuit to execute control strategy one; control strategy one is that the two control components of the upper half bridge and the two control components of the lower half board are respectively turned on for the first time and the second time within one cycle, so that the electric energy of the high-voltage DC bus is transmitted to the new energy vehicle charging unit after rectification.

[0025] In some preferred implementations, when the exchange requirement is to store the electric energy of the high-voltage AC bus, the target control mode is:

[0026] Control the high-voltage rectifier unit to connect with the high-voltage AC bus, disconnect the photovoltaic energy unit from the photovoltaic power generation, and disconnect the high-voltage rectifier unit from the high-voltage DC bus; then control the H-bridge inverter circuit to execute control strategy two; control strategy two is that within one cycle, one control component in the upper half bridge and one control component in the lower half bridge are turned on for a third time, and another control component in the upper half bridge of the H-bridge inverter circuit and another control component in the lower half bridge are turned on for a fourth time, so as to invert AC into DC; at the same time, the first H-bridge rectifier circuit and the second H-bridge rectifier circuit both execute control strategy one; control strategy one is that the two control components in the upper half bridge and the two control components in the lower half board are turned on for a first time and a second time, respectively, within one cycle, so that the electric energy of the high-voltage AC bus is stored in the storage station;

[0027] When the exchange demand is to use the electric energy of the high-voltage AC bus as the electric energy required by the new energy vehicle charging unit, the target control mode is:

[0028] Control the high-voltage rectifier unit and the high-voltage AC bus to be connected, the photovoltaic energy unit to be disconnected from the photovoltaic power generation, and the high-voltage rectifier unit to be disconnected from the high-voltage DC bus; then control the H-bridge inverter circuit to execute control strategy two; control strategy two is that within one cycle, one control component in the upper half bridge and one control component in the lower half bridge are turned on for a third time, and another control component in the upper half bridge of the control component of the H-bridge inverter circuit and another control component in the lower half bridge are turned on for a fourth time to invert AC into DC; at the same time, the second H-bridge rectifier circuit executes control strategy one; control strategy one is that the two control components of the upper half bridge and the two control components of the lower half board are turned on for the first time and the second time respectively within one cycle, so that the electric energy of the high-voltage AC bus is transmitted to the new energy vehicle charging unit.

[0029] In some preferred implementations, when the exchange requirement is to convert the electric energy of the high-voltage AC bus into the electric energy of the high-voltage DC bus, the target control mode is:

[0030] Controlling the high-voltage rectifier unit to be connected to the high-voltage AC bus, the high-voltage rectifier unit to be connected to the high-voltage DC bus, and disconnecting the energy unit from the photovoltaic power generation; then controlling all control components of the first H-bridge rectifier circuit and the second H-bridge rectifier circuit to be turned off; at the same time, controlling the H-bridge inverter circuit to execute control strategy 2; control strategy 2 is that within one cycle, one control component in the upper half bridge and one control component in the lower half bridge are turned on for a third time, and another control component in the upper half bridge of the H-bridge inverter circuit and another control component in the lower half bridge are turned on for a fourth time, so as to invert AC into DC;

[0031] When the exchange requirement is to convert the electric energy of the high-voltage DC bus into the electric energy of the high-voltage AC bus, the target control mode is:

[0032] Control the high-voltage rectifier unit to be connected to the high-voltage AC bus, the high-voltage rectifier unit to be connected to the high-voltage DC bus, and the energy unit to be disconnected from the photovoltaic power generation; then control all control components of the first H-bridge rectifier circuit and the second H-bridge rectifier circuit to be turned off; at the same time, control the H-bridge inverter circuit to execute control strategy two; control strategy two is that within one cycle, one control component in the upper half bridge and one control component in the lower half bridge of the control component of the H-bridge inverter circuit are turned on for the fifth time, and another control component in the upper half bridge and another control component in the lower half bridge are turned on for the sixth time to invert DC into AC.

[0033] The beneficial effects of the technical solution provided by this application include:

[0034] Since the high-voltage module includes a high-voltage rectifier unit, the output end of the high-voltage rectifier unit is connected in parallel with a high-voltage DC unit, a high-voltage inverter unit and a photovoltaic energy unit, and the high-voltage inverter unit is connected to a high-voltage AC unit; the high-voltage DC unit is used to control the on-off of the high-voltage rectifier unit and the high-voltage DC bus, and the high-voltage AC unit is used to control the on-off of the high-voltage rectifier unit and the high-voltage AC bus; the photovoltaic energy unit is used to control the on-off of the high-voltage rectifier unit and the photovoltaic power generation device; the low-voltage module includes a low-voltage rectifier unit and a new energy vehicle charging unit, and the access end of the low-voltage rectifier unit is connected to the energy storage unit, which is used to store and release the peak and valley electricity of the storage station; the output end of the low-voltage rectifier unit is connected to the A transformer unit is connected to the access end of the high-voltage rectifier unit; the new energy vehicle charging unit is connected to the transformer unit; the exchange control device is connected to the energy storage unit, the low-voltage rectifier unit, the photovoltaic energy unit, the high-voltage rectifier unit and the high-voltage inverter unit, and is used to control the operation of the energy storage unit, the low-voltage rectifier unit, the high-voltage rectifier unit and the high-voltage inverter unit according to the exchange requirements; the structure of the new exchange system formed above can convert the electricity generated by photovoltaic power generation, the electricity charged by the vehicle, the electricity stored during peak and valley periods, and the high-voltage AC and DC electricity in an interconnected exchanger as needed, which saves costs and is conducive to the conversion and utilization of different electrical energies. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0036] Figure 1 An overall schematic diagram of an electric energy conversion system based on an AC / DC hybrid distribution network provided in an embodiment of the present application;

[0037] Figure 2 A schematic diagram of the topological structure of an electric energy conversion system based on an AC / DC hybrid distribution network provided in an embodiment of the present application. DETAILED DESCRIPTION

[0038] The embodiment of the present application provides an electric energy conversion system based on an AC / DC hybrid distribution network to solve the problem in the related art that the operator needs to move the spraying device himself every time the spraying position is changed, and setting up scaffolding is also time-consuming and labor-intensive.

[0039] Please refer to Figure 1-Figure 2 , an electric energy conversion system based on an AC / DC hybrid distribution network, comprising:

[0040] The high-voltage module includes a high-voltage rectifier unit, the output end of which is connected in parallel to a high-voltage DC unit, a high-voltage inverter unit, and a photovoltaic unit, and the high-voltage inverter unit is connected to a high-voltage AC unit; the high-voltage DC unit is used to control the on / off of the high-voltage rectifier unit and the high-voltage DC bus, the high-voltage AC unit is used to control the on / off of the high-voltage rectifier unit and the high-voltage AC bus; the photovoltaic unit is used to control the on / off of the high-voltage rectifier unit and the photovoltaic power generation device;

[0041] The low-voltage module includes a low-voltage rectifier unit and a new energy vehicle charging unit. The access end of the low-voltage rectifier unit is connected to an energy storage unit, which is used to store and release peak and valley electricity from the power station. The output end of the low-voltage rectifier unit is connected to a transformer unit for connecting to the access end of the high-voltage rectifier unit. The new energy vehicle charging unit is connected to the transformer unit.

[0042] The switching control device is connected to the energy storage unit, low-voltage rectifier unit, photovoltaic energy unit, high-voltage rectifier unit and high-voltage inverter unit, and is used to control the operation of the energy storage unit, low-voltage rectifier unit, high-voltage rectifier unit and high-voltage inverter unit according to the switching demand to convert electrical energy.

[0043] The functions of the above-mentioned access and output ends are not single, and they can be regarded as connection ports; because under a certain conversion requirement, the function of the access end is also the output end, and the function of the output end is also the access end; the structure of the new exchange system formed above can convert the electricity generated by photovoltaic power generation, the electricity charged by vehicles, the electricity stored during peak and valley times, and the high-voltage AC and DC electricity in an interconnected exchanger as needed, saving costs, facilitating the conversion and utilization of different electric energies, and improving the conversion and utilization rate of electric energy.

[0044] In some preferred embodiments, reference Figure 1 and Figure 2The low-voltage rectifier unit includes a first capacitor connected in parallel with the energy storage unit, a low-voltage DC load, and a first H-bridge rectifier circuit; the high-voltage rectifier unit includes a second capacitor connected in parallel with the high-voltage DC unit, a high-voltage DC load, and a second H-bridge rectifier circuit; the high-voltage inverter unit includes a third capacitor connected in parallel with the high-voltage AC unit and an H-bridge inverter circuit.

[0045] The first H-bridge rectifier circuit, the second H-bridge rectifier circuit, and the H-bridge inverter circuit each include four MOS transistor switches and four diodes. Each MOS transistor corresponds to a diode, forming four control components. These four control components are connected to form an H-bridge circuit. This arrangement results in a simple and uncomplicated circuit with simple and effective control logic.

[0046] The following describes a method for converting electric energy based on an AC / DC hybrid distribution network, which includes the following steps:

[0047] Provide an electric energy conversion system based on an AC / DC hybrid distribution network, and connect it to the power storage station, high-voltage AC busbar, and photovoltaic power generation device;

[0048] The corresponding target control mode is obtained based on the exchange demand, and then the exchange control device is used to control the energy storage unit, low-voltage rectifier unit, photovoltaic unit, high-voltage rectifier unit and high-voltage inverter unit according to the target control mode.

[0049] Example 1

[0050] When the exchange demand is to store the electric energy generated by the photovoltaic power generation device, the target control mode is:

[0051] The photovoltaic energy unit is controlled to be connected to the photovoltaic power generation device, the high-voltage rectifier unit is disconnected from the high-voltage DC bus, and the high-voltage rectifier unit is disconnected from the high-voltage AC bus; then the first H-bridge rectifier circuit and the second H-bridge rectifier circuit are controlled to execute control strategy one; control strategy one is that the two control components of the upper half bridge and the two control components of the lower half board are respectively turned on for a first time and a second time within one cycle; the control components of the H-bridge inverter circuit are all turned off to store the electric energy generated by the photovoltaic power generation device in the storage station.

[0052] Example 2

[0053] When the exchange demand is to use the electric energy generated by the photovoltaic power generation device as the electric energy required by the new energy vehicle charging unit, the target control mode is:

[0054] Control the photovoltaic energy unit to be connected with the photovoltaic power generation device, disconnect the high-voltage rectifier unit from the high-voltage DC bus, and disconnect the high-voltage rectifier unit from the high-voltage AC bus; control the control components of the first H-bridge rectifier circuit and the H-bridge inverter circuit to be completely turned off, and the second H-bridge rectifier circuit to execute control strategy one; control strategy one is that the two control components of the upper half bridge and the two control components of the lower half board are respectively turned on for the first time and the second time within one cycle, so that the electric energy generated by the photovoltaic power generation device is transmitted to the new energy vehicle charging unit after rectification.

[0055] Example 3

[0056] When the exchange requirement is to store the electric energy of the high-voltage DC bus, the target control mode is:

[0057] The high-voltage rectifier unit is controlled to be connected to the high-voltage DC bus, the photovoltaic energy unit is disconnected from the photovoltaic power generation, and the high-voltage rectifier unit is disconnected from the high-voltage AC bus; then the first H-bridge rectifier circuit and the second H-bridge rectifier circuit are controlled to execute control strategy one; control strategy one is that the two control components of the upper half bridge and the two control components of the lower half board are respectively turned on for a first time and a second time within one cycle, and the control components of the H-bridge inverter circuit are all turned off, so that the electric energy of the high-voltage DC bus is stored in the storage station.

[0058] Example 4

[0059] When the exchange demand is to use the electric energy of the high-voltage DC bus as the electric energy required by the new energy vehicle charging unit, the target control mode is:

[0060] Control the high-voltage rectifier unit and the high-voltage DC bus to be connected, the photovoltaic energy unit to be disconnected from the photovoltaic power generation, and the high-voltage rectifier unit to be disconnected from the high-voltage AC bus; then control the control components of the first H-bridge rectifier circuit and the H-bridge inverter circuit to be all turned off, and the second H-bridge rectifier circuit to execute control strategy one; control strategy one is that the two control components of the upper half bridge and the two control components of the lower half board are respectively turned on for the first time and the second time within one cycle, so that the electric energy of the high-voltage DC bus is transmitted to the new energy vehicle charging unit after rectification.

[0061] Example 5

[0062] When the exchange requirement is to store the electric energy of the high-voltage AC bus, the target control mode is:

[0063] Control the high-voltage rectifier unit to connect with the high-voltage AC bus, disconnect the photovoltaic energy unit from the photovoltaic power generation, and disconnect the high-voltage rectifier unit from the high-voltage DC bus; then control the H-bridge inverter circuit to execute control strategy two; control strategy two is that within one cycle, one control component in the upper half bridge and one control component in the lower half bridge are turned on for a third time, and another control component in the upper half bridge of the H-bridge inverter circuit and another control component in the lower half bridge are turned on for a fourth time, so as to invert AC into DC; at the same time, the first H-bridge rectifier circuit and the second H-bridge rectifier circuit both execute control strategy one; control strategy one is that the two control components in the upper half bridge and the two control components in the lower half board are turned on for a first time and a second time, respectively, within one cycle, so that the electric energy of the high-voltage AC bus is stored in the storage station;

[0064] Example 6

[0065] When the exchange demand is to use the electric energy of the high-voltage AC bus as the electric energy required by the new energy vehicle charging unit, the target control mode is:

[0066] Control the high-voltage rectifier unit and the high-voltage AC bus to be connected, the photovoltaic energy unit to be disconnected from the photovoltaic power generation, and the high-voltage rectifier unit to be disconnected from the high-voltage DC bus; then control the H-bridge inverter circuit to execute control strategy two; control strategy two is that within one cycle, one control component in the upper half bridge and one control component in the lower half bridge are turned on for a third time, and another control component in the upper half bridge of the control component of the H-bridge inverter circuit and another control component in the lower half bridge are turned on for a fourth time to invert AC into DC; at the same time, the second H-bridge rectifier circuit executes control strategy one; control strategy one is that the two control components of the upper half bridge and the two control components of the lower half board are turned on for the first time and the second time respectively within one cycle, so that the electric energy of the high-voltage AC bus is transmitted to the new energy vehicle charging unit.

[0067] Example 7

[0068] When the exchange requirement is to convert the electric energy of the high-voltage AC bus into the electric energy of the high-voltage DC bus, the target control mode is:

[0069] Control the high-voltage rectifier unit to be connected to the high-voltage AC bus, the high-voltage rectifier unit to be connected to the high-voltage DC bus, and the energy unit to be disconnected from the photovoltaic power generation; then control all control components of the first H-bridge rectifier circuit and the second H-bridge rectifier circuit to be turned off; at the same time, control the H-bridge inverter circuit to execute control strategy two; control strategy two is that within one cycle, one control component in the upper half bridge and one control component in the lower half bridge of the control component of the H-bridge inverter circuit are turned on for a third time, and another control component in the upper half bridge and another control component in the lower half bridge are turned on for a fourth time to invert AC into DC.

[0070] Example 8

[0071] When the exchange requirement is to convert the electric energy of the high-voltage DC bus into the electric energy of the high-voltage AC bus, the target control mode is:

[0072] Control the high-voltage rectifier unit to be connected to the high-voltage AC bus, the high-voltage rectifier unit to be connected to the high-voltage DC bus, and the energy unit to be disconnected from the photovoltaic power generation; then control all control components of the first H-bridge rectifier circuit and the second H-bridge rectifier circuit to be turned off; at the same time, control the H-bridge inverter circuit to execute control strategy two; control strategy two is that within one cycle, one control component in the upper half bridge and one control component in the lower half bridge of the control component of the H-bridge inverter circuit are turned on for the fifth time, and another control component in the upper half bridge and another control component in the lower half bridge are turned on for the sixth time to invert DC into AC.

[0073] It should be understood from the above that the first H-bridge rectifier circuit, the second H-bridge rectifier circuit and the H-bridge inverter circuit all utilize the rectification and inversion functions of the H-bridge circuit, mainly to control the conduction of the four control group components at different times to achieve rectification and inversion, thereby performing conversion and utilization of various electrical energies and between high and low voltages.

[0074] In the description of this application, it should be noted that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0075] It should be noted that, in this application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0076] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. An electric energy conversion system based on an AC / DC hybrid distribution network, characterized in that: It includes: The high-voltage module includes a high-voltage rectifier unit, a high-voltage DC unit, a high-voltage inverter unit and a photovoltaic unit are connected in parallel to the output end of the high-voltage rectifier unit, and the high-voltage inverter unit is connected to a high-voltage AC unit; the high-voltage DC unit is used to control the on-off of the high-voltage rectifier unit and the high-voltage DC bus, the high-voltage AC unit is used to control the on-off of the high-voltage rectifier unit and the high-voltage AC bus; the photovoltaic unit is used to control the on-off of the high-voltage rectifier unit and the photovoltaic power generation device; A low-voltage module, comprising a low-voltage rectifier unit and a new energy vehicle charging unit, wherein the access end of the low-voltage rectifier unit is connected to an energy storage unit, and the output end of the low-voltage rectifier unit is connected to a transformer unit for connecting to the access end of the high-voltage rectifier unit; the new energy vehicle charging unit is connected to the transformer unit; The switching control device is connected to the energy storage unit, the low-voltage rectifier unit, the photovoltaic energy unit, the high-voltage rectifier unit and the high-voltage inverter unit, and is used to control the operation of the energy storage unit, the low-voltage rectifier unit, the high-voltage rectifier unit and the high-voltage inverter unit according to the switching demand.

2. The electric energy conversion system based on the AC / DC hybrid distribution network according to claim 1, characterized in that: The low-voltage rectifying unit comprises a first capacitor connected in parallel with the energy storage unit, a low-voltage DC load and a first H-bridge rectifying circuit; The high-voltage rectifying unit comprises a second capacitor connected in parallel with the high-voltage DC unit, a high-voltage DC load and a second H-bridge rectifying circuit; The high-voltage inverter unit includes a third capacitor and an H-bridge inverter circuit connected in parallel with the high-voltage AC unit.

3. The electric energy conversion system based on the AC / DC hybrid distribution network according to claim 2, characterized in that: The first H-bridge rectifier circuit, the second H-bridge rectifier circuit and the H-bridge inverter circuit each include four MOS tube switches and four diodes; wherein each MOS tube corresponds to a diode to form four control components; and the four control components are connected to form an H-bridge circuit.

4. A power conversion method based on an AC / DC hybrid distribution network, applied to the power conversion system according to claim 3, characterized in that: It includes the following steps: Acquire a corresponding target control mode based on the exchange demand, and use the exchange control device to control the energy storage unit, the low-voltage rectifier unit, the photovoltaic unit, the high-voltage rectifier unit and the high-voltage inverter unit according to the target control mode; The control strategies of the first H-bridge rectifier circuit and the second H-bridge rectifier circuit include: control strategy one, in one cycle, two control components of the upper half bridge and two control components of the lower half bridge are respectively turned on; The control strategy of the H-bridge inverter circuit includes: control strategy 2, in one cycle, one control component in the upper half bridge is turned on with one control component in the lower half bridge for a period of time, and another control component in the upper half bridge is turned on with another control component in the lower half bridge for another period of time.

5. The electric energy conversion method based on the AC / DC hybrid distribution network according to claim 4, characterized in that: When the exchange demand is to store the electric energy generated by the photovoltaic power generation device, the target control mode is: The photovoltaic energy unit is controlled to be connected with the photovoltaic power generation device, the high-voltage rectifier unit is disconnected from the high-voltage DC bus, and the high-voltage rectifier unit is disconnected from the high-voltage AC bus; then the first H-bridge rectifier circuit and the second H-bridge rectifier circuit are controlled to execute control strategy one, and all control components of the H-bridge inverter circuit are turned off to store the electric energy generated by the photovoltaic power generation device into the storage station.

6. The electric energy conversion method based on the AC / DC hybrid distribution network according to claim 4, characterized in that: When the exchange demand is to use the electric energy generated by the photovoltaic power generation device as the electric energy required by the new energy vehicle charging unit, the target control mode is: Control the photovoltaic energy unit to be connected with the photovoltaic power generation device, disconnect the high-voltage rectifier unit from the high-voltage DC bus, and disconnect the high-voltage rectifier unit from the high-voltage AC bus; control the control components of the first H-bridge rectifier circuit and the H-bridge inverter circuit to be completely closed, and the second H-bridge rectifier circuit to execute control strategy one, so that the electric energy generated by the photovoltaic power generation device is transmitted to the new energy vehicle charging unit after rectification.

7. The electric energy conversion method based on the AC / DC hybrid distribution network according to claim 4, characterized in that: When the switching requirement is to store the electric energy of the high-voltage DC bus, the target control mode is: The high-voltage rectifier unit is controlled to be connected to the high-voltage DC bus, the photovoltaic energy unit is disconnected from the photovoltaic power generation, and the high-voltage rectifier unit is disconnected from the high-voltage AC bus; then the first H-bridge rectifier circuit and the second H-bridge rectifier circuit are controlled to execute control strategy one, and all control components of the H-bridge inverter circuit are turned off to store the electric energy of the high-voltage DC bus in the storage station.

8. The electric energy conversion method based on the AC / DC hybrid distribution network according to claim 4, characterized in that: When the exchange demand is to use the electric energy of the high-voltage DC bus as the electric energy required by the charging unit of the new energy vehicle, the target control mode is: Control the high-voltage rectifier unit and the high-voltage DC bus to be connected, the photovoltaic energy unit to be disconnected from the photovoltaic power generation, and the high-voltage rectifier unit to be disconnected from the high-voltage AC bus; then control the control components of the first H-bridge rectifier circuit and the H-bridge inverter circuit to be all closed, and the second H-bridge rectifier circuit to execute control strategy one, so that the electric energy of the high-voltage DC bus is transmitted to the new energy vehicle charging unit after rectification.

9. The electric energy conversion method based on the AC / DC hybrid distribution network according to claim 4, characterized in that: When the exchange demand is to store the electric energy of the high-voltage AC bus, the target control mode is: Control the high-voltage rectifier unit to connect with the high-voltage AC bus, disconnect the photovoltaic energy unit from the photovoltaic power generation, and disconnect the high-voltage rectifier unit from the high-voltage DC bus; then control the H-bridge inverter circuit to execute control strategy 2 to invert AC into DC; at the same time, both the first H-bridge rectifier circuit and the second H-bridge rectifier circuit execute control strategy 1 to store the electric energy of the high-voltage AC bus in the storage station; When the exchange demand is to use the electric energy of the high-voltage AC bus as the electric energy required by the new energy vehicle charging unit, the target control mode is: The high-voltage rectifier unit is controlled to be connected to the high-voltage AC bus, the photovoltaic energy unit is disconnected from the photovoltaic power generation, and the high-voltage rectifier unit is disconnected from the high-voltage DC bus; then the H-bridge inverter circuit is controlled to execute control strategy two to invert AC into DC; at the same time, the second H-bridge rectifier circuit executes control strategy one to transmit the electric energy of the high-voltage AC bus to the new energy vehicle charging unit.

10. The electric energy conversion method based on the AC / DC hybrid distribution network according to claim 4, characterized in that: When the exchange demand is to convert the electric energy of the high-voltage AC bus into the electric energy of the high-voltage DC bus, the target control mode is: Control the high-voltage rectifier unit to be connected to the high-voltage AC bus, the high-voltage rectifier unit to be connected to the high-voltage DC bus, and the energy unit to be disconnected from the photovoltaic power generation; then control all control components of the first H-bridge rectifier circuit and the second H-bridge rectifier circuit to be turned off; at the same time, control the H-bridge inverter circuit to execute control strategy 2 to invert AC into DC; When the exchange demand is to convert the electric energy of the high-voltage DC bus into the electric energy of the high-voltage AC bus, the target control mode is: Control the high-voltage rectifier unit to be connected to the high-voltage AC bus, the high-voltage rectifier unit to be connected to the high-voltage DC bus, and the energy unit to be disconnected from the photovoltaic power generation; then control all control components of the first H-bridge rectifier circuit and the second H-bridge rectifier circuit to be turned off; at the same time, control the H-bridge inverter circuit to execute control strategy two to invert DC into AC.

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