一种基于电流预测的电压型逆变器死区补偿方法

Method of Dead-time Compensation for Voltage Source Inverters Based on Current Predictive

针对电压型逆变器因电流采样延时和寄生电容影响而导致死区补偿不准的问题,提出了一种基于电流预测的死区补偿方法,并建立了电压型PWM逆变器驱动异步电机的数学模型,将电流瞬时值和开关状态代入该模型去预测未来时刻的电流值,以此判断电流极性。分析了因死区时间和开关器件的寄生电容引起的电压误差,在每个周期内对输出电压进行了补偿。最后,改进算法在160 k W感应电机变频调速系统上进行了实验验证,结果证明了该补偿方法能有效改善电机的电流波形。

A method of dead-time compensation for voltage source inverters based on current predictive was introduced, which take the delay of current sampling and parasitic capacitance effects leading to inaccurate of dead time compensation into account. The mathematical model for voltage-source PWM inverter driving asynchronous motor was built, and the current value in future could be calculated by substituting the instantaneous value of current and switching state into the model. Then the current polarity could be judged. Analyses were made of the voltage error causing by dead- time and parasitic capacitance of switching devices, and compensation for output voltage was presented with each cycle. At last, in order to test the performances of the improved method, experiments were carried on variable frequency speed control system for 160 kW induction motor. The experiment results prove the validity of the proposed method.