SMES用电压源型功率调节系统的建模与控制方法研究

Study on Modeling and Control System Design Method for VSC-Based PCS Used in SMES

以电压源型功率调节系统为对象,研究其建模及其控制方法。首先给出电压源型功率调节系统的结构,包括电压源型变流器和斩波器的主电路拓扑结构及其连接关系;随后导出占空比表达的PCS低频数学模型,并使用非线性变换实现状态方程线性化,基于线性化后的模型给出有功功率、无功功率及直流电压解耦的控制系统设计方法;最后在Matlab/Simulink环境下对PCS功率跟踪能力及SMES装置抑制风电功率波动的效果进行了仿真验证。仿真结果表明:所设计的PCS系统控制器对阶跃和正弦规律变化的功率指令具有优秀的跟踪能力,同时具有较强稳定直流电压的能力,该PCS接口的超导储能装置应用于风力发电系统中,能够达到减小风电功率波动,平息出力的目标。

This paper chooses the voltage source converter based PCS as the object to study the method of its modeling and control.The structure of PCS,which includes the topologies of VSC and DC-DC chopper,was presented firstly,followed by the deduction of the low frequency state equation expressed by duty cycle.Then the state equation was linearized by non-linear transformation,the result of which was based to design the control system that achieves decoupled control between active power,reactive power and DC voltage.Finally,the ability of PCS to track power orders in the form of step change or sine change and the effectiveness of SMES system to stabilize output power of generator in single machine infinite bus system were checked using Matlab/Simulink software.The results of simulation show that PCS designed in this paper has the ability to trace power order in form of sine and step,accompanied by the strong resistance of DC voltage to disturbance,the SMES system interfaced by this PCS can accelerate the calm down of generator power oscillation,so enhance the stability of power system.