基于相电压反馈的三电平逆变器死区补偿

为防止逆变器上下桥臂直通,通常需要在开关管驱动信号中加入死区时间,但死区时间可能导致输出电压和电流畸变.针对二极管中点箝位型NPC(neutral-point clamped)三电平逆变器的死区补偿问题,提出了一种基于相电压反馈在线计算误差电压的死区补偿策略.该策略根据反馈相电压,在dq同步旋转坐标系下对误差电压进行实...

Three-level Inverter Dead-time Compensation Based on Phase Voltage Feedback

To prevent the direct-through of the upper and lower arms of an inverter, it is usually necessary to add dead-time to the driving signal of switching tubes. However, the dead-time may lead to the distortion of output voltage and current. To solve the dead-time compensation problem of a diode neutral-point clamped (NPC) three-level inverter, a dead-time compensation strategy is proposed based on the voltage errors obtained using the online phase voltage feedback calculation. Under the d-q synchronous rotating coordinate system, the error voltage is calculated in real time according to phase voltage feedback. At the same time, aimed at the current phase shift problem caused by the traditional filter used in the current polarity judgment, a Kalman filter is adopted to process the three-phase output current under the d-q synchronous rotating coordinate system. Afterwards, the filtered current is reconstructed into a three-phase stationary coordinate system, thus determining the current polarity without phase shift. Simulation results show that the proposed method can accurately judge the current polarity and adjust the compensation voltage adaptively, thereby effectively reducing the harmonic content of the output voltage.