摘要
虚拟同步发电机(VSG)算法是一种新型并网逆变器控制方案,可使得逆变器具有虚拟的惯性和阻尼,更适用于大规模分布式发电,具有更好的电网兼容性。针对多种虚拟阻尼的实现方案,本文通过小信号模型对比分析了不同形式虚拟阻尼环节对系统性能的影响,指出基于电网电压反馈的动态阻尼项虽可改善VSG的动态性能,但不合理的锁相环参数影响VSG的动态特性,甚至会破坏系统稳定性。在上述分析的基础上,本文提出了一种无锁相环的VSG算法,设计了基于功率超前反馈的动态阻尼环节,并给出了一种基于相位裕度的动态阻尼参数设计方法。最后,利用5kW功率硬件在环半实物实验平台验证了所提出的控制策略的可行性和正确性。
The grid-connected inverter implementing the virtual synchronous generator(VSG) controller can take advantage of the virtual inertia and damping winding to improve the stability of the frequency and voltage of the power grid. However, phase-locked loop(PLL) in virtual damping winding weakens the damping effect during the transient and increases the complexity of the system. In this paper, a leading-network based damping controller without PLL is proposed after analyzing the inverse effect of PLL on the performance of the damping winding using VSG small-signal models. A phase margin-constrained straightforward parameter setting method for proposed VSG is presented. The correctness of the design is verified by MATLAB/Simulink simulation platform.
引文
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