低分频同步SVPWM下调制度非线性补偿方法研究

Research on nonlinear compensation method of modulation index with synchronousSVPWM of low pulse ratio

针对低分频同步SVPWM实际输出调制度与目标调制度存在偏差的问题,重点对低分频同步SVPWM的理论调制度与实际调制度对应关系进行推导说明,提出一种可适用于不同分频的调制度非线性补偿方法。当分频数大于3时,根据当前目标调制度,调用该分频实际调制度与理论调制度对应关系数组读取补偿后的理论调制度;当分频数等于3时,根据公式直接求出补偿后的理论调制度,采用补偿后的理论调制度进行三相脉冲比较值计算。试验结果表明,所提方法可准确进行调制度非线性补偿,补偿后实际调制度与目标调制度一致,控制精度得到有效提高。

In allusion to the deviation between the actual output modulation index and the target modulation index with synchronous SVPWM of low pulse ratio.The corresponding relationship between theoretical modulation index and actual modulation index with synchronous SVPWM of low pulse ratio is mainly deduced,and a nonlinear compensation method of modulation index suitable for different pulse ratio is proposed.When pulse ratio is greater than 3,the array of corresponding relationship between the actual modulation index and theoretical modulation index with this pulse ratio is called according to the current target modulation index,and the theoretical modulation index after compensation is read.When pulse ratio is equal to 3,the theoretical modulation index after compensation is directly obtained according to formula,and the theoretical modulation index after compensation is used to calculate the comparison value of three⁃phase pulses.The experimental results show that the proposed method can accurately compensate the nonlinear modulation index,the actual modulation index is consistent with the target modulation index after compensation,and the control precision is effectively improved.