PMSG风机直流电容虚拟惯性控制及惯性影响分析

DC link Capacitor Virtual Inertia Control and Inertia Effect Analysis for PMSG based Wind Turbine

摘要:

为解决风电在电力系统中渗透率不断增加而导致的电网惯量不断降低的问题，提出了永磁直驱风机参与电网频率调节的直流电容虚拟惯性控制。该虚拟电容控制能够耦合直流电压和交流频率，利用储存在直流电容中的静电能提供惯性支撑，并能有效地抑制频率变化的斜率和减小最大频率偏差，提高频率的动态特性。此外，详细研究了影响虚拟惯性时间常数的关键参数以及虚拟惯性时间常数与直流电容的确切关系，并给出了相关参数的选取方法。最后，在PSCAD/EMTDC中搭建仿真算例，仿真结果表明直流电容虚拟惯性控制能够准确模拟同步发电机的惯性响应，其控制性能优于传统转子虚拟惯性控制。

Abstract:

In order to solve the problem that power grid inertia is continuously reduced due to the increasing penetration of wind power in power system, a DC link capacitor inertia control of permanent magnet synchronous generator (PMSG) based wind turbine(WT) for participating in grid frequency regulation is proposed. With the virtual inertia control, the DC link voltage and AC frequency are coupled to release the static electricity stored in DC link capacitor to provide inertial support for power system during frequency disturbance. This virtual inertia control can effectively suppress the rate of change of frequency (ROCOF) and reduce the maximum deviation of frequency under frequency disturbance, and improve the dynamic characteristics of frequency. In addition, the key parameters affecting the virtual inertia time constant and the exact relationship between virtual inertia time constant and DC link capacitor are discussed in details, and the selection method of the relevant parameters is given. Finally, a simulation study is built in PSCAD/EMTDC, and the simulation results show that the DC link capacitor virtual inertia control can accurately simulate the inertia response of synchronous generator, whose control performance is better than that of the traditional rotor virtual inertia control.