常规SVPWM算法需要进行多次复杂的坐标变换并涉及大量的浮点乘法运算,增加了控制器的运算负荷且占用更多的内存空间。针对这一问题提出快速SVPWM方法,利用压缩变化将基础电压矢量转移至特殊位置,进而可以利用电压矢量变换后的两个分量的符号和大小判断其所在的扇区,无需进行其他数学运算;同时发现双边对称7段SVPWM三相占空比计算的特殊规律,将6个扇区分为3组,每组的2个扇区具有相同的运算规则,基于该发现提出简明扇区判据,只对矢量所属的组别进行判定,由判据结果可以直接获得三相占空比,进一步简化算法,减少了运算量和程序代码长度。通过仿真对算法的可行性进行了验证,同时在以DSP为控制核心的永磁电机实验平台上进行了实验。实验表明,在浮点DSP平台上快速SVPWM算法的运算速度提高了38%,同时减少了程序代码所占的存储空间,节省了45个字节的内存空间。
The conventional SVPWM method requires repeated coordinate transformation and a large num-ber of floating point multiplications, which increases controller’ s computational load and takes up much more memory space. Hence a fast algorithm of SVPWM was put forward to solve this problem. This algo-rithm converted the conventional reference space voltage vector into a special position by compression transformation and then only made use of sign and magnitude of two components which were converted by voltage vector to determine the sector, without other mathematical operations. At the same time, by dis-covering special rules of calculation for bilaterally symmetrical seven-segment SVPWM three-phase duty, the six sectors were divided into three groups and the two sectors of each group have the same operation rules. Based on this discovering, a concise criterion was presented, which only needs to determine the group of vectors and the three-phase duty ratio were obtained directly. So the algorithm was further sim-plified and the length of program code and computational cost were reduced. Experimental results show that the operation speed of the fast algorithm based on floating-point DSP platform increases by 38%. The storage space of the program code is reduced effectively and memory space saves 45 bytes.