Multidimensional Space-Vector PWM Algorithm Using Branch Space Voltage Vector

Typical algorithms of multidimensional space-vector pulsewidth modulation (SVPWM) divide (n-1) dimensional space into (n-1)/2 subplanes with decoupling matrix or symmetrical component approach. However, the determination of effective sectors and appropriate space voltage vectors takes a heavy computing burden. Taking the five-phase inverter as example, the relationship between the operation time of branch switches and the dwell times of active space vectors in the SVPWM method is analyzed in this paper. Then, the branch space voltage vector (BSVV) corresponding to the individual active branch voltage is defined and the synthesis of other active space voltage vectors using BSVVs is given. Furthermore, only the BSVVs are chosen as the base vectors to synthesize the reference voltage vector, and a novel SVPWM algorithm is present. The operation time of branch switch is deduced, and the equivalence of the normalized load-phase voltages and operation times of branch switches is emphasized and used to analyze the simulation results. The zero-sequence voltage vector is also included in the algorithm as a parameter and its effects on the dwell time of the BSVVs, the modulation index and the common-mode voltage are explicated. Finally, the extension to an n-phase system is discussed. The algorithm eliminates the selection of sectors and proper active space vectors, and can effectively control the dwell time of switches of multiphase inverter. Experimental results proved the feasibility and effectiveness of the algorithm.