基于相位与幅值补偿的虚拟同步发电机低电压穿越控制

摘 要：虚拟同步发电机（virtual synchronous generator，VSG）通过模拟同步发电机的工作原理，引入虚拟惯量与阻尼系数，提高了分布式电源并网的稳定性。但是当电网发生电压跌落时，电压的跌落与恢复均会造成电网电压的相位与幅值发生跳变，而传统的VSG控制策略难以解决此问题。为此，在分析了传统VSG控制下低电压穿越时存在问题的基础之上，本文提出了一种基于相位与幅值补偿的VSG低电压穿越控制方法。首先分析了电网电压跌落与恢复对电网造成的不同影响。其次在电网电压跌落期间，通过将VSG输出电压和电网电压之间的相位与幅值差控制在允许范围内来实现过流抑制、输出功率的快速稳定以及无功补偿的目的。然后在电网电压恢复时，通过快速补偿消除了VSG输出电压和电网电压之间的相位与幅值差，从而抑制因电网电压跳变而造成的过流等问题。最后，通过MATLAB/Simulink仿真验证所提控制策略的有效性。

Low voltage ride-through control of virtual synchronous generator based on phase and amplitude compensation

Abstract: The stability of distributed power grid connection is improved by the virtual synchronous generator (VSG) simulating the working principle of synchronous generators and introducing the characteristics of virtual inertia and damping coefficient. However, when the voltage of the power grid drops, the phase and amplitude of the grid voltage will jump due to the drop and recovery of the grid voltage, which is difficult to solve by the traditional VSG control strategy. Therefore, based on the analysis of the problems of low-voltage ride-through under traditional VSG control, a VSG low-voltage ride-through control method based on phase and amplitude compensation is proposed. First, the different impacts of grid voltage dip and recovery on the grid are analyzed in detail. Secondly, when the phase and amplitude difference between the VSG output voltage and the grid voltage is controlled within the allowable range during the grid voltage dip, the purposes of overcurrent suppression, fast stable output power, and reactive power compensation are all achieved. Then, when the grid voltage is restored, the phase and amplitude difference between the VSG output voltage and the grid voltage is eliminated by fast compensation, and the overcurrent caused by grid voltage jumping is also solved. Finally, the effectiveness of the proposed control strategy is verified by MATLAB/Simulink simulation.