一种基于DVR的低压微网系统关键负载恒压供电控制策略

A Novel Control Scheme Based on DVR for Constant Voltage Power Supply for Critical Load

微网中的线路阻抗、逆变器输出阻抗以及电网电压波动都会造成微网中关键负载电压的波动。为使电压敏感负载恒压供电,在微网中引入动态电压补偿器(DVR)。给出了DVR的主电路,其控制策略包含有源阻尼环、瞬时电压环以及有效值电压外环,分别保证DVR的工作稳定性、动态特性以及稳态精度。给出了闭环控制参数的设计方法。仿真结果表明,将DVR应用到微网中可保证关键负载恒压供电,并具有优良的动态性能和稳态精度。

The voltage of critical load is affected by l^ne impedance, output impedance of inverter and fluctua- tion of utility grid voltage. The dynamic voltage restorer is introduced to microgrid so that the critical load can realize constant voltage power supply. The main circuit is given. The control strategy for DVR concludes an active damping controller, an instantaneous voltage controller and a RMS voltage controller, which can ensure that the DVR has the characteristic of good stability, dynamic response and zero-error. The parameters for controller are designed. The simulation results verify that the performance of proposed control strategy for DVR is excellent.