六相电压源逆变器PWM算法

针对相移30°双Y联结六相电机,建立了一种基于邻近最大四矢量的六相电压源逆变器空间矢量脉宽调制(SVPWM)算法。根据基波电压调制系数的大小,将调制范围分为正弦调制区和非正弦调制区。在正弦调制区内,逆变器输出正弦相电压;在非正弦调制区内,提出了两种调制策略,通过注入适量的6k±1(k=1,3,5,…)次谐波电压来提高基波电压的幅值。其中的第二种调制算法同时考虑到了参考电压矢量幅值和相角的变化,所以得到了更少的谐波含量。针对算法中PWM波形不对称难以硬件实现的问题,根据电压平均值相等的原则对PWM波形进行了中心化处理,转变成易于硬件实现的形式。实验结果验证了算法的有效性。

PWM Techniques for Six-Phase Voltage-Source Inverters

For six-phase motor which has two sets of Y-connected three-phase windings spatially phase shifted by 30 electrical degrees,a space vector pulse width modulation(SVPWM) algorithm of six-phase voltage-source inverter based on adjacent four largest voltage vectors is discussed.According to the value of modulation index,the modulation range could be divided into sinusoidal range and non-sinusoidal range.In sinusoidal range,the inverter produced sinusoidal phase voltage.In non-sinusoidal range,two modulation algorithms are proposed to increase the magnitude of fundamental voltage by injecting the harmonic voltages of 6k±1(k=1,3,5,…).The second algorithm considering both magnitude and phase angle of the reference voltage has fewer harmonics than the first one.To simplify the hardware implementation,the PWM waveform is centralized with the same average voltage.The validity of the algorithm is confirmed by experimental results.