基于输出电压反馈的虚拟同步发电机多环控制策略

Multiloop Control Strategy for Virtual Synchronous Generator Using Only Output Voltage Feedback

基于虚拟同步发电机VSG(virtual synchronous generator)控制的微网用储能逆变器广泛应用于分布式发电系统中,VSG输出电压的波形质量是衡量其性能的重要方面。为提高VSG的供电质量,提出了只采用输出电压反馈的多环控制策略。其中,输出电压一次微分反馈回路起到有源阻尼的作用,可有效地抑制LC滤波器的谐振;输出电压以及输出电流前馈解耦回路可使电流内环等效成一阶系统,从而提高系统的动态响应。在考虑系统控制延时的基础上,采用极点配置技术对电压与电流双环控制器参数进行设计。所提控制策略,在负载阶跃扰动情况下既能实现快速的动态响应,又能获得很好的稳态特性。仿真和实验结果都验证了该控制策略的可行性与有效性。

Energy storage inverters based on virtual synchronous generator（ VSG ） control are usually used for all kinds of distributed generation interfaces in a microgrid, the output voltage waveform quality of VSG is an important aspect to measure its performance. To improve the VSG power supply quality, a multiloop control strategy for VSG with the only output voltage feedback is proposed. The output voltage differential feedback loop actively damps the output LC filter resonance and thus increases the system stability margin. The decoupling of output voltage as well as output current makes the current inner loop equivalent to a first order system and thus improves the system dynamic response to load disturbance. Considering the effect of system control delay, the pole placement technique has been used to design the voltage and current dual-loop controller parameters. The proposed control strategy can achieves very fast dynamic response and also possess good steady state performance with the load step changing. Simulation and experimental results verify the feasibility and effectiveness of the proposed control strategy.