Three-phase four switch inverter is one of the low cost control schemes of three-phase six switch inverter, but the problems of torque ripple and neutral potential unbalance exist in three-phase four switch inverter. At present, many scholars at home and abroad put forward many control methods for three-phase four switches, which can effectively reduce the torque ripple of motor, but can not effectively solve the problem of capacitor neutral point potential. If the capacitor neutral point potential compensation is not considered, it will lead to poor effect of SVM DTC, affect the balance of three-phase current, increase the torque ripple of the motor, and will lead to downtime in serious cases. Based on the basic vector analysis of three-phase four switch inverter, a new capacitor voltage compensation scheme was proposed in this paper. It was then compared with the current compensation algorithm through analysis, simulation and experimental verification, and the results show that the metor compensated by algorithm proposed in this paper has a better performance.%三相四开关逆变为三相六开关是逆变的一种低成本控制方案,而三相四开关逆变器存在转矩脉动大、中点电位不平衡的问题.国内外学者对于三相四开关提出了很多控制方法,能够有效地减小电机的转矩脉动问题,但都未能有效地解决电容中点电位的问题.若不考虑电容中点电位补偿问题,则会导致SVM DTC效果变差,影响三相电流的平衡性,增大电机的转矩脉动,严重情况下还会导致停机.从三相四开关逆变器的基本矢量分析,提出一种新的电容电压补偿方案,并与目前的补偿算法进行比较分析和仿真与实验验证,表明通过本文算法补偿后的电机运行具有较好的性能.
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