基于改进阻尼控制的VSG控制策略

VSG Control Strategy Based on Improved Damping Control

传统的虚拟同步发电机(VSG)控制策略对于各种不同工况下引起的功率与频率振荡的抑制以及动态性能的调节方面存在许多问题,通过系统传递函数进行分析,描述了传统VSG存在的一些控制问题,如功率振荡抑制与响应时间难以协调、由于下垂控制环节导致的频率稳态偏差以及频率特性要求缓慢调节对于阻尼大小需求与输出功率阻尼需求的矛盾,因此,提出一种改进阻尼控制的VSG控制策略,在功-频控制器中附加阻尼环节,利用传递函数通过理论分析,详细描述如何解决传统VSG控制策略存在的控制矛盾。最后,在仿真系统中模拟功率参考值变化、电网频率下降等工况,采用改进的VSG控制策略的系统均可以很好的实现控制目标。

Traditional virtual synchronous generator(VSG)control strategies have many issues in suppressing power and frequency oscillations under various operating conditions and regulating dynamic performance.By analyzing the system transfer function,this paper described some control problems of traditional VSG,such as the difficulty in coordinat-ing power oscillation suppression and response time,frequency steady-state deviation caused by droop control,and the contradiction between the slow adjustment requirement of frequency characteristics and the damping requirement for damping size and output power.Therefore,an improved damping control strategy for VSG was proposed,which added a damping loop to the power-frequency controller.Through theoretical analysis using transfer functions,this paper provided a detailed description of how to solve the control contradictions in traditional VSG control strategies.Finally,simulation systems were used to simulate scenarios such as changes in power reference values and grid fre-quency reduction.The systems with the improved VSG control strategy can effectively achieve the control objectives.