三相四桥臂虚拟同步发电机预同步、多环路控制及负载不平衡控制方法

设计了一种三相四桥臂虚拟同步发电机多环路控制策略,通过有功和无功的解耦控制使逆变器模拟同步发电机的一次调频、一次调压、惯性和励磁特性,并改进了控制方法,在功率环之后级联电压电流双环,改善微电网动态调节性能。针对平滑并网,利用一种预同步控制策略,使逆变器的频率相位和幅值追踪电网电压。同时,针对带不平衡负载时的电压不平衡、频率波动问题,提出了一种变频率自适应谐振控制方法。仿真与实验验证了所提控制方法的可行性。

A Pre-Synchronization,Multiple Loops Control,and Unbalanced Load Control Strategies for Three-Phase Four-Leg Virtual Synchronous Generator

This paper designs a multiple loops control strategy for three-phase four-leg virtual synchronous generator (VSG). The decoupling control of power is used to make inverter simulate the primary frequency modulation, primary voltage modulation, inertia and excitation characteristics of synchronous generator. To improve the dynamic regulation performance of micro-grid, voltage and current double loop is cascaded after the power loop. To connect the grid smoothly, a synchronization control strategy is adopted to track the voltage frequency, phase and amplitude of grid. A variable frequency adaptive resonance control strategy is used to suppress unbalanced voltage and frequency fluctuation caused by unbalanced load. The simulation and experiments validate the effectiveness of the control strategy.