PWM激励下异步电机铁耗等值电阻模型

Model of Equivalent Iron Loss Resistance of Induction Motor Fed by PWM

通过分析PWM激励下异步电机铁耗变化的特点,提出了一种综合考虑电机运行工况和PWM波形特性的铁耗等值电阻模型。基于铁耗分离原理,使用三个电阻分别等效电机铁耗的磁滞分量、经典涡流分量和异常涡流分量,并推导了正弦激励下各个电阻分量的表达式;进而通过分析PWM激励与正弦激励下铁耗间关系,对正弦激励下铁耗模型进行修正,获得PWM激励下铁耗模型;最后提出了确定该模型参数的实验方案。所建模型中各个电阻分量随电机运行频率和PWM波形的调制系数变化而变化,且变化规律各不相同,提高了电机铁耗计算的准确性。仿真和实验验证了该模型的正确性和有效性。

Model of equivalent iron loss resistance of induction motor（IM） fed by PWM is established which could consider the motor＇s operation condition and PWM waveform property by analyzing characteristic of iron loss variation. Based on iron loss separation model, three resistances are used to represent each component of the total iron loss which consists of hysteresis, classical loss and excess loss and then the expressions for these resistance under sinusoidal excitation are deduced. These expressions are modified by analyzing relationship of iron loss of IM under sinusoidal and PWM excitation, and then the model of iron loss resistance under PWM excitation is built. An experiment scheme is proposed to determining the parameters of the model. Each resistance in the model varies with the motor＇s operating frequency and modulation index of PWM waveform in different manners, and calculation accuracy of iron loss is improved. Correctness and validity of the proposed model is verified by the simulation and the experiment results.