针对传统虚拟同步发电机(virtual synchronous generator,VSG)控制中逆变器输出阻抗和线路阻抗不同而引起的功率环流问题,提出一种改进型虚拟同步发电机功率控制方法。首先,在VSG电磁方程中引入虚拟电抗,解决低压线路阻抗模型中阻性成分带来的功率耦合问题,使得逆变器输出功率能够独立控制。其次,在VSG励磁控制器中附加公共连接点电压 (voltage at the point of common coupling,VPCC) 调节器,抑制因线路阻抗不同而引起的无功环流,并可在负荷突增情况下维持VPCC稳定。最后在孤岛运行的低压微电网中进行了仿真,仿真结果证明了该控制策略的可行性与有效性。
英文摘要:
To solve the problem of power circulation caused by different output impedance of inverter and line impedance in the control of the virtual synchronous generator (VSG), a power control method based on improved VSG is proposed in this paper. Firstly, the virtual reactance is introduced in VSG electromagnetic equations to solve the power coupling problem caused by the resistive component in the line impedance model, so that the output power of the inverter can be controlled independently. Secondly, the VPCC regulator is attached to VSG excitation controller to suppress the reactive circulation caused by different line impedance, and the VPCC can be maintained stable in case of sudden load increase. Finally, the simulation is carried out in the low voltage microgrid with islanding operation, the simulation results show that control strategy has correctness and effectiveness.