一种基于电机模型预测的三电平死区补偿方法

Method of Dead-time Compensation in Three-level Inverter Based on Motor Model Predictive Control

分析了三电平电压型逆变器死区效应产生的机理,针对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,提出了一种基于电机模型预测的三电平电压型逆变器死区补偿方法。该方法首先建立了三电平电压型逆变器驱动异步电机的数学模型,并根据该模型和瞬时电流采样值,计算出实际瞬时电流的预测值,然后将电流预测值和器件开关状态代入该模型计算出准确的补偿时间,实时的对补偿电压进行调整。最后,改进算法在7.5 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。

The dead-time effect of the three-level voltage inverter was analyzed. A method of dead-time compensation for three-level voltage source inverters based on motor model predictive was introduced, for which the delay of current sampling and parasitic capacitance effects could lead to inaccurate of dead time compensation into account. The mathematical model of induction motor with three-level voltage source inverter had been established, 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. At last, in order to test the performances of the improved method, experiments were carried on variable frequency speed control system for 7.5 kW induction motor. The experiment results proved that the current waveform of induction motor is effectively improved by the proposed method.