Distortion Compensation Control Designed for H-Bridge Cascade Multi-Level Converter under Low Speed Condition

Under low speed condition, the output voltage distortion of the cascade multilevel converter by low index modulation and dead-time is existed. In the paper, a novel vector control is presented to compensate the current distortion. A vector control scheme was put forward for asynchronous machine driven by a cascaded multi-level inverter to compensate dead-time effect of inverter and provide sinusoidal currents. The distortion causes and distortion component extraction method were analyzed in detail. Meanwhile, based on the least squares method, a PID time-delay compensator for enhancing the system response property is devised. Finally, the experimental test platform for the prototype is designed. The simulation results and experimental data show the effectiveness of the proposed algorithm.