基于负载电流滑模观测的逆变器滑模控制

Inverter Sliding Mode Control Based on Load Current Sliding Mode Observer

提出一种基于负载电流滑模观测的单相电压型逆变器滑模控制策略。结合串级系统思想,将逆变系统分解为电压子系统和电感电流子系统,电压子系统的控制输出为电感电流子系统的控制给定量。电压子系统采用滑模控制,并将负载电流观测值进行前馈补偿,以克服负载电流对逆变器控制性能的影响,同时有效避免了传统逆变器滑模控制中切换增益过大问题。实验结果表明,所提观测器响应速度快、观测误差小,系统输出无静差、输出电压谐波含量很少,且对直流母线和负载扰动具有强鲁棒性。

A sliding mode control strategy based on load current sliding mode observer for single phase voltage invert- er is proposed.The continuous mathematical model of the inverter is established by averaging method over switching period.Combined with cascade system idea,the inverter system is decomposed into the voltage subsystem and the in- ductance subsystem while the output of voltage subsystem is set as the reference of the inductance subsystem.The sliding mode control is adapted as the control strategy for voltage subsystem and observed load current is used for feed-forward compensation.According to the proposed method,the load current disturbance and chattering problem caused by large switch gain are weakened.The experimental results show that the response of observer is fast and ob- servation error is small and the steady error of output voltage is almost zero and total harmonic distortion is extremely low.Meanwhile, the system is robust to the disturbance of DC voltage source and loads.