A master-slave control method for energy storage inverter based on virtual synchronous generator

Abstract

The invention discloses a master-slave control method for an energy storage inverter based on a virtual synchronous generator. The energy storage inverter comprises a master control inverter and a slave control inverter, wherein the master control inverter adopts a voltage source output mode based on the virtual synchronous generator to provide amplitude and frequency of network voltage, provide virtual inertia and a virtual damping ratio according to the capacity of the master control inverter, and meanwhile provide static active and passive current quotas to each inverter; the slave control inverter adopts a current source output mode based on the virtual synchronous generator to receive static active and passive current quotas issued by the master control inverter, and meanwhile provide the virtual inertia according to the capacity of the slave control inverter. According to the method, in island parallel operation, a load is non-uniform and fluidity is relatively low under various load conditions, and relatively high output voltage power quality is provided; compared with traditional master-slave control, a controller structure does not need to be changed when switching between grid connection and disconnection is performed, and the master control inverter and the slave control inverter independently provide the virtual inertia without depending on communication, so that improvement on system stability under dynamic condition is facilitated, and the reliability is relatively high.

Description

technical field [0001] The invention relates to a control method of an energy storage inverter, in particular to a master-slave control method of an energy storage inverter based on a virtual synchronous generator. Background technique [0002] In recent years, as the penetration rate of new energy power generation units in the power system continues to increase, at the same time, the traditional centralized primary energy is gradually reduced, the moment of inertia of the system is gradually reduced, the frequency fluctuation becomes larger, and the intermittent characteristics of the primary energy are more severe. The frequency fluctuation of the power grid is exacerbated, making the frequency stability of the system more and more serious. In the traditional power system, factors such as the droop characteristic of the synchronous generator set (Generator Set-Genset) and the large moment of inertia play a key role in maintaining the voltage and frequency stability of the ...

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Problems solved by technology

[0007] A Master-Slave Three-phase Inverter Power Supply Parallel Control Technology Research Based on CAN Bus (Guo Jing, Yanshan University, Master Thesis, 2006) gave a master-slave three-phase inverter power supply Parallel control technology, all three-phase inverters share the voltage control loop, and the obtained current command is distributed to each inverter for current closed-loop control. However, for the application of parallel and off-grid dual modes, it is necessary to perform on-grid and off-grid switching control. Increased system complexity and affected output voltage performance

[0008] In short, the existing energy storage inverter control technology based on virtual synchronous generators is difficult to take into account the comprehensive performance of dynamic response, load current sharing, output voltage power quality, etc.

For the current control technology, as the number of units connected in parallel increases, the uneven load current will gradually increase, and it is difficult to simultaneously satisfy the output voltage power command and load current sharing characteristics under nonlinear load conditions such as rectifier bridges; while the traditional control technology based on the main The three-phase inverter power supply controlled by the slave cannot be connected to the grid, and then provide fast inertia to the system to maintain the voltage and frequency stability of the micro-grid system. In addition, when the traditional master-slave control and off-grid switching need to switch controllers, the control scheme is complicated

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