柔性多状态开关直流侧电压纹波的抑制策略

DC Side Voltage Ripple Suppression Strategy on Flexible Multi-state Switch

柔性多状态开关是由多端共直流母线变流器组成的新型馈线互联电力装置,而电网电压不平衡时柔性多状态开关直流母线电压产生的波动,会严重影响其正常运行和设备的使用寿命。为此,分析了直流侧电压波动原理,提出了一种新的正负序双环直流侧电压控制策略。正序采用功率前馈控制稳定直流电压稳态误差,负序采用单正弦信号谐振反馈控制以抑制直流电压周期性波动。最后搭建了仿真平台,对不同情况下的直流侧电压波动进行了仿真实验,仿真结果验证了所提方案的有效性。该策略能有效地抑制柔性多状态开关在多端口同时不平衡下的直流侧电压的纹波,输出电流无谐波电流且电流峰值被限定在额定范围内。

The flexible multi-state switch(FMSS)is a new type of feeder interconnection power device,which is composed of the multi-terminal common DC bus converter.When the grid voltage is unbalanced,the fluctuation of DC voltage of the FMSS will seriously affect its normal operation and the service life of the device.After analyzing the principle of DC-side voltage fluctuation,a new dual-loop DC-side voltage control strategy is proposed to solve this problem.The positive-sequence loop uses power feedforward control to stabilize the DC voltage steady-state error,and the negative-sequence loop uses the single sinusoidal signal resonance feedback control to suppress periodic ripple of DC voltage.Finally,a simulation platform is built to simulate the DC-side voltage fluctuation under different conditions.The simulation results verify the effectiveness of the proposed scheme.This strategy can effectively suppress the ripple of the DC side voltage of the flexible multi-state switch under multi-port simultaneous unbalance,the output current has no harmonic current,and the current peak is limited to the rated range.