计及等效负载变化的消弧逆变器性能分析与设计

分析了消弧逆变器等效负载的性质，结果表明：等效负载是有源负载，等效源具有较大的幅值和较宽的变化范围；随过渡电阻和故障距离的变化，等效负载阻抗可呈现阻性、阻感性和阻容性。这一结果表明逆变器需要在负载性质改变和等效电源扰动的情况下，仍能稳定跟踪包含多频次的给定电流。对抗扰性和跟踪性要求的提高，增加了设计难度。鉴于此，提出了消弧逆变器输出滤波器和控制器的设计方法。输出滤波器采用滤波电容分流法进行设计，保证了逆变器能输出包含多频次的电流。采用电容串联电阻来抑制阻感负载情况下带来的谐振失稳问题，并给出了串联电阻的计算方法。控制器采用了定带宽设计法，带宽选定在幅频特性重合段。控制器参数设计准则为：保证阻容负载情况下传函幅频特性低频段具有较高增益。采用PSCAD/EMTDC仿真验证了结论的正确性和所提设计方法的可行性。

Performance analysis and design of an arc suppression inverter considering equivalent load change

The characteristics of the equivalent load of an arc suppression inverter are analyzed. The results show that the equivalent load is active load and the equivalent source has large amplitude and a wide range of variation. With the change of transition resistance and fault distance, the equivalent load impedance can show resistance, resistance inductance and resistance capacitance. This result shows that the inverter needs to be able to track the given current containing multiple frequencies stably under the condition of load property change and equivalent power disturbance. The improvement of anti-interference and tracking requirements increases the design difficulty. In view of this, the design method of output filter and controller for an arc-suppression inverter is proposed. The output filter is designed by the filter capacitor shunt method to ensure that the inverter can output current containing multiple frequencies. Capacitor series resistance is used to suppress the resonance instability problem caused by resistance-inductance load, and the calculation method of series resistance is given. The controller adopts the fixed bandwidth design method, and the bandwidth is selected in the amplitude-frequency characteristic overlap section. The design criterion of controller parameters is to ensure that the amplitude frequency characteristic of the transfer function has high gain in the low frequency band in the condition of resistance capacitance load. The correctness of the conclusion and the feasibility of the proposed design method are verified by PSCAD/EMTDC simulation.This work is supported by the National Natural Science Foundation of China (No. 61963014).