AC/DC hybrid microgrid coupled inverter cascade control implementation method

Abstract

The invention relates to an AC / DC hybrid microgrid coupled inverter cascade control implementation method, which comprises the steps of firstly designing a current vector control strategy, performingPark inverse transformation on an output result of the current vector control strategy, and performing space vector pulse width modulation to obtain a PWM wave for driving a three-phase inverter, wherein the current reference input of the current control loop is the output of the voltage control loop; secondly, designing a voltage vector control strategy, wherein voltage reference input of the voltage vector control strategy is output of the virtual impedance control loop; thirdly, designing a virtual impedance control loop, wherein the voltage reference input of the virtual impedance controlloop is the output of the virtual synchronous machine control loop; then, designing a virtual synchronous machine control loop; and finally, designing a grid-connected synchronous control loop, and closing a grid-connected switch when a grid-connected condition is met. According to the invention, the robustness of the controller to parameter disturbance and external disturbance and the system inertia and frequency stability of the AC-DC hybrid microgrid coupling inverter can be improved; and parallel operation of the AC-DC hybrid microgrid coupling inverter is realized, off-grid and grid-connected seamless switching can be realized, and the redundancy and reliability of the system are improved.

Description

technical field [0001] The invention relates to a method for realizing cascade control of coupled inverters in an AC / DC hybrid microgrid, and belongs to the technical field of smart grids. Background technique [0002] With the increase in the proportion of new energy access, AC-DC hybrid microgrid will be the trend of future grid development. AC / DC hybrid microgrid coupled inverters play a key role in integrating inverters to interface distributed generation units into microgrids. In order to improve the system inertia of the AC-DC hybrid microgrid coupled inverter to maintain the frequency stability of the AC side grid, a cascaded control structure is often used, including droop control loops, PI-based voltage control loops and current control loops. However, the traditional droop control has the disadvantages of poor frequency stability and difficulty in providing sufficient system inertia; the PI-based voltage and current double closed-loop control strategy has the disa...

AI Technical Summary

Problems solved by technology

Traditional synchronous control strategies require complex phase-locked loop controllers to achieve power angle and frequency synchronization

The phase-locked loop controller has the disadvantages that the control parameters are difficult to adjust, and its control performance directly affects the performance of the synchronous control algorithm.

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