Abstract: In the traditional dynamic sector direct power control system,the dynamic response of the DC side voltage is slow and the power pulsation is large. To solve this problem,the transient moment when dc voltage may fluctuate greatly is taken into account in the process of sector division,and secondly according to comparison of the active power and reactive power deviations,the power error is introduced to compare two level hysteresis comparators and a more precise switch table is put forward. After the valid vector is obtained from the switch table,to reduce the power pulsation and the dependence of the system on high sampling frequency,the zero vector is introduced to optimize the power waveform in one control period,and the duty cycle function is simplified according to the law of the proposed switch table so that the duty cycle can be calculated directly from the power error information while the switch table is being read,and the degradation of system robustness caused by complex power calculation can be avoided. The simulation results show that this proposed scheme can effectively reduce the power ripple and current harmonics, and improve the dynamic response ability of the system.