Application of improved SVPWM algorithm in three phase inverter
                                                JIANG Tao, XV Ming xia, CHE Xiang zhong
                           （Technology Center, CRRC. Dalian R&D Co. Ltd., Dalian 116052, China）

Abstract: In order to solve thecoordinate transformation and complex calculationof traditional SVPWM algorithm, the mechanism of SVPWM algorithm was deduced and analyzed; the inherent law of three phase space vector modulation was studied and a modified non sector algorithm based on abc coordinates was proposed. The proposed modulation algorithm was used to fulfill the traditional SVPWM function. By using the internalrelationship of the three phase voltage, the modulation time function of SVPWM algorithm was deduced, and the computational complexity of SVPWM algorithm was reduced without complex coordinate transformation and sector judgment. The modified SVPWM algorithm was then applied to the 245 kVA subway auxiliary inverter to realize the accurate closed loop control of the three phase voltage. The theory and experiment show that the algorithm does not require complex calculation, and has the advantages of quickness and simplicity, as well as practicality and feasibility in the three phase inverter.

Key words: SVPWM; pulse width modulation; coordinate transformation; space vector; conduction angle