基于超前滞后环节附加前馈阻尼的VSG控制策略

VSG Control Strategy Based on Additional Feedforward Damping of Leading and Lagging Links

虚拟同步发电机(virtual synchronous generator,VSG)在引入同步机二阶转子运动方程,增大电力系统等效惯量的同时,也引入了同步发电机的振荡特性,有功低频振荡等动态稳定性问题也随之而来。引入调速侧电力系统稳定器(governor power system stabilizer,GPSS)能有效抑制VSG的功率低频振荡,但其在超调量及调节时间方面的控制效果仍有待提高。通过建立VSG的小信号模型从极点配置角度分析其稳定性,揭示基于GPSS的VSG控制策略在功率动态响应上存在较高超调和较长调节时间的原因。基于此,参考GPSS控制思想,提出了一种基于超前滞后环节附加前馈阻尼补偿的虚拟同步发电机控制策略。并从理论上分析验证了所提控制策略在不影响系统稳态特性的前提下,能够提供调整自由度更高的正阻尼,在有效地抑制功率超调的同时提高了系统的调节速度,从而更好地抑制了有功功率的低频振荡。最后通过MATLAB/Simulink进行对比仿真,仿真结果与理论分析结果一致,证明了所提控制策略的正确性和有效性。

Virtual synchronous generator(VSG)not only introduces the second-order rotor motion equation of the syn-chronous machine to increase the equivalent inertia of the power system,but also introduces the oscillation characteristics of the synchronous generator,leading to dynamic stability issues such as active low-frequency oscillation.The introduc-tion of a governor power system stabilizer(GPSS)can effectively suppress the low-frequency oscillation of VSG power,but its control effect in terms of overshoot and regulation time still needs to be improved.By establishing a small signal model of VSG and analyzing its stability from the perspective of pole configuration,it is revealed that the VSG control strategy based on GPSS has high overshoot and long adjustment time in power dynamic response.Thereby,referring to the GPSS control concept,a virtual synchronous generator control strategy based on additional feed-forward damping compensation with leading and lagging links is proposed.And it is theoretically analyzed and verified that the proposed control strategy can provide positive damping with higher degrees of adjustment freedom without affecting the steady-state characteristics of the system,effectively suppressing the power overshoot while improving the system’s ad-justment speed,thereby better suppressing low-frequency oscillation of active power.Finally,comparative simulation was conducted using MATLAB/Simulink,and the simulation results were consistent with the theoretical analysis results,proving the correctness and effectiveness of the proposed control strategy.