Energy storage power conversion system

Abstract

The utility model relates to the technical field of energy storage control, in particular to an energy storage power conversion system, which comprises a plurality of energy storage power generation devices, a multi-stage switching circuit, a power transmission bus, a coordination control terminal and a power distribution monitoring terminal, the power distribution monitoring terminal is connected with a power transmission bus and is in wireless connection with the coordination control terminal, and the coordination control terminal is connected with the multi-stage switching circuit and each energy storage power generation device; each energy storage power generation device is connected with the input end of the multi-stage switching circuit, and the output end of the multi-stage switching circuit is electrically connected with the power transmission bus. By monitoring the power supply electric energy of the power transmission bus and the load power in real time, accurate sensing of the load demand of the power grid is realized, so that each energy storage power generation device is triggered to carry out power generation output, the system can flexibly adjust the parallel number of the energy storage power generation devices according to the load demand, and energy storage power generation grid connection with different powers is realized.

Description

TECHNICAL FIELD

[0001] The utility model relates to energy storage control technical field, concretely is a kind of energy storage power conversion system. BACKGROUND

[0002] Distributed energy storage device is a new type of power supply equipment, which can realize power generation and storage simultaneously, providing stable power support for power grid. With the rapid development of new energy power generation technology, distributed energy storage device grid-connected generation technology has been widely used in power grid transmission due to its flexible structure, scalable capacity and off-grid operation mode.

[0003] However, when a large number of distributed energy storage devices are connected to the power grid for energy storage discharge, the output of the distribution network power supply side becomes unstable and loses controllability. In addition, due to the different energy storage capacities of each energy storage device, and the possibility of the power grid driving all devices to generate power at the same time when controlling the energy storage device grid-connected generation, it is easy to cause energy waste when the electricity demand is low. Voltage imbalance at the output end of different energy storage devices can also disturb the power grid, leading to a decrease in power quality. SUMMARY

[0004] To solve the above problems, the utility model provides a kind of energy storage power conversion system, including several energy storage power generation devices, multistage switching circuit, power transmission bus, coordination control terminal and distribution monitoring terminal;The distribution monitoring terminal connects power transmission bus, and is wirelessly connected with coordination control terminal, and the coordination control terminal is connected with multistage switching circuit and each energy storage power generation device respectively;Each energy storage power generation device is connected to the input end of multistage switching circuit, and the output end of multistage switching circuit is electrically connected to power transmission bus.

[0005] The multistage switching circuit includes several power supply input branches and isolation filter circuit, and each power supply input branch is connected in parallel and connected to the isolation filter circuit.

[0006] The power supply input branch includes power supply terminal, contactor switch and protection resistor;The power supply terminal is connected to the energy storage power generation device, the power supply terminal is connected to the contactor switch, the output fire line of the contactor switch is connected to the isolation filter circuit, and the output zero line of the contactor switch is connected to the ground through the protection resistor.

[0007] In order to realize the conduction control of each power supply input branch in the multistage switching circuit, the coordination control terminal is connected to the contactor switch of each power supply input branch.

[0008] The energy storage power generation device includes energy storage battery, inverter and inverter control module, the energy storage battery is electrically connected to the inverter, and the inverter is connected to the inverter control module.

[0009] In order to realize parallel connection of each energy storage power generation device without interconnection line, the inverter control module comprises a voltage and current sampling unit, a power compensation unit and a droop control unit, the droop control unit is electrically connected with the voltage and current sampling unit and the power compensation unit respectively, the voltage and current sampling unit is connected with the output end of the inverter, and the droop control unit is electrically connected with the inverter.

[0010] In order to suppress high-frequency harmonics generated by the energy storage power generation device during grid-connected power generation, the isolation filter circuit adopts an LCL filter.

[0011] In the specific embodiment, the single energy storage power generation device is connected with one power supply input branch.

[0012] Meanwhile, the energy storage power generation device further comprises a battery management system, which is electrically connected with the energy storage battery and can detect the storage power capacity of the energy storage battery in real time.

[0013] The battery management system is in communication connection with the coordination controller, can replace power generation according to the storage power capacity of the energy storage battery, and ensures the continuity of the energy storage power generation.

[0014] The beneficial effects are that the utility model is a kind of energy storage power conversion system, by real-time monitoring power supply power of transmission bus and load power, the accurate perception to grid load demand is realized, to trigger each energy storage power generation device to generate output, effectively supplement grid power, guarantee the stability of power supply;Meanwhile, through multistage switching circuit, system can flexibly adjust the parallel connection number of energy storage power generation device according to load demand, realize the grid-connected power generation of different power energy storage, not only improve the utilization of energy storage power generation device, also make system can better adapt to the change of load demand, realize the dynamic balance of power supply;Energy storage power generation device realizes parallel connection without interconnection line by droop control, improves the stability of transmission bus voltage when each energy storage power generation device is grid-connected power generation, and the active power sharing degree when multistage switching circuit is parallel connected. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is the structure diagram of energy storage power conversion system;

[0016] Figure 2 It is multistage switching circuit diagram. DETAILED DESCRIPTION

[0017] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings.

[0018] EMBODIMENT

[0019] Reference Figure 1The embodiment provides a kind of energy storage power conversion system, including several energy storage power generation devices, multistage switching circuit, power transmission bus, coordination control terminal and distribution monitoring terminal;The coordination control terminal is wirelessly connected with distribution monitoring terminal, distribution monitoring terminal connects power transmission bus, can monitor the power supply electric energy and load power of power transmission bus, and when load power is greater than power supply electric energy, energy storage grid-connected power generation instruction is transmitted to coordination control terminal.Each energy storage power generation device is connected to the input end of multistage switching circuit, and the multistage switching circuit is electrically connected to the power transmission bus, and the coordination control terminal is electrically connected to each energy storage power generation device and multistage switching circuit, on the one hand, coordination control terminal can trigger each energy storage power generation device to generate power output, on the other hand, coordination control terminal can control multistage switching circuit according to the monitoring signal of distribution monitoring terminal, and the number of parallel connection of the energy storage power generation device is turned on by multistage switching circuit, to realize the energy storage power generation of different power grid-connected.

[0020] The multistage switching circuit includes several power supply input branches, isolation filter circuit and inductance, and the power supply input branch includes power supply terminal, contactor switch and protection resistor;The power supply terminal is connected to energy storage power generation device, the power supply terminal is connected to the contactor switch, the output fire line of the contactor switch is connected to the isolation filter circuit, the output zero line of which is connected to one end of the inductance through the protection resistor, and the other end of the inductance is grounded.Each power supply input branch is connected in parallel and connected to the isolation filter circuit, and the isolation filter circuit is an LCL filter, which can effectively suppress high-frequency harmonics.In order to realize the balance between the power generation power of energy storage power generation device and the demand power of load, the coordination control terminal is connected to the contactor switch of each power supply input branch, and the number of energy storage power generation device for power output is realized by controlling the contactor switch of different power supply input branches to be closed / opened, to realize the conversion of energy storage power generation power.

[0021] Meanwhile, the energy storage power generation device includes energy storage battery, inverter and inverter control module, the energy storage battery is electrically connected to the inverter, the inverter is connected to the inverter control module, and the energy storage battery releases the stored electric energy to the inverter, which is converted into alternating current by the inverter, and the inverter is connected to a power supply input branch, and when the contactor switch of the power supply input branch is closed and turned on, grid-connected power generation confluence can be carried out.

[0022] In order to ensure the stability of the bus voltage of each energy storage power generation device when generating electricity in parallel, and improve the active power sharing degree when the multi-stage switching circuit is connected in parallel, the energy storage power generation device is connected in parallel without interconnection line by using droop control, the inverter control module comprises a voltage and current sampling unit, a power compensation unit and a droop control unit, the droop control unit is electrically connected with the voltage and current sampling unit and the power compensation unit, the voltage and current sampling unit is connected with the output end of the inverter, the current and voltage data of the output end of the inverter can be obtained and transmitted to the droop control unit, the droop control unit is electrically connected with the inverter, the droop control unit generates a pulse width modulation signal through the power compensation unit, and the pulse width modulation signal is transmitted to the inverter for power modulation, so as to realize the current sharing control of the power generation of each energy storage power generation device.

[0023] In order to ensure the service life of the energy storage power generation device, the energy storage power generation device further comprises a battery management system, the battery management system is in communication connection with the coordination controller, the battery management system is electrically connected with the energy storage battery, can detect the remaining battery capacity of the energy storage battery in real time, can send a low power signal to the coordination controller when the remaining battery capacity of the energy storage battery is low, and if the power input branch of the energy storage power generation device is in a closed power generation state, the contactor switch is controlled to be opened, so as to avoid over-discharge of the energy storage battery and prolong the service life of the energy storage power generation device. At the same time, the coordination controller obtains the energy storage battery capacity of the energy storage power generation device which is not generating electricity in parallel, and replaces the power generation, so as to ensure the continuity of the energy storage power generation.

Claims

1. An energy storage power conversion system, characterized by, The energy storage power generation device, the multi-stage switching circuit, the power transmission bus, the coordination control terminal and the power distribution monitoring terminal are connected with each other. The multi-stage switching circuit comprises a plurality of power supply input branches and an isolation filter circuit.

2. The energy storage power conversion system of claim 1, wherein, The power supply input branch comprises a power supply terminal, a contactor switch and a protection resistor.

3. The energy storage power conversion system of claim 2, wherein, The coordination control terminal is connected with the contactor switch of each power supply input branch.

4. The energy storage power conversion system of claim 1, wherein, The energy storage power generation device comprises an energy storage battery, an inverter and an inverter control module.

5. The energy storage power conversion system of claim 4, wherein, The inverter control module comprises a voltage and current sampling unit, a power compensation unit and a droop control unit.

6. The energy storage power conversion system of claim 1, wherein, The isolation filter circuit adopts an LCL filter.

7. The energy storage power conversion system of claim 1, wherein, The single energy storage power generation device is connected with one power supply input branch.

8. The energy storage power conversion system of claim 4, wherein, The energy storage power generation device further comprises a battery management system which is electrically connected with the energy storage battery.

9. The energy storage power conversion system of claim 8, wherein, The battery management system is in communication connection with the coordination controller.

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