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在电力机车牵引逆变器等大功率传动系统中,受到最高开关频率以及输出电压、电流谐波性能的限制,通常需要采用特殊的优化脉宽调制策略。其中,电流谐波最小PWM(current harmonic minimum PWM,CHMPWM)得益于其谐波电流最优的特点,可以使电机控制性能,转矩脉动,谐波损耗等都得到间接优化,受到越来越多的关注。文中在计算得到不同开关角个数下CHMPWM的开关角分布后,对CHMPWM下异步牵引电机的定子磁链轨迹在不同开关角个数下随调制比的变化规律进行分析,以此为基础,提出一种基于定子磁链轨迹的CHMPWM在不同开关角个数和开关角区段之间进行切换的策略。该切换策略不需要对切换前后谐波电流进行复杂的理论分析,实现简单。仿真和实验结果都证明了该切换策略的有效性。
In high-power transmission systems such as traction drives for electric locomotives, limited by the highest switching frequency, output voltage and current harmonic performance, a special optimized pulse width modulation strategy is usually required. Among them, the current harmonic minimum PWM (CHMWM) benefits from its optimal harmonic current characteristics, so that the motor control performance, torque ripple, harmonic loss, etc. are indirectly optimized, more and more More attention. After calculating the switching angle distribution of CHMPWM with different numbers of switching angles, the variation law of the stator flux trajectory of induction motor under different switching angles with the modulation ratio is analyzed based on this. A Kind of Strategy Based on Stator Flux Link Trajectory CHMPWM Switching Between Different Number of Switching Angle and Switching Angle. The switching strategy does not require complex theoretical analysis of the harmonic current before and after switching, to achieve simple. Simulation and experimental results prove the effectiveness of the switching strategy.