Optimized Space Vector Modulation strategy for five phase voltage source inverter with third harmonic injection

One of the advantages of a five-phase motor is to maximize the torque per ampere ratio where a quasi-rectangular air gap flux distribution is obtained. The problem is that the Space Vector Modulation (SVM) strategy, used in multiphase drives, proves to be a complex task. This is due to a mutual relation between voltage vectors in multiple orthogonal spaces. The main problem in SVM algorithms for multiphase inverters is to point a set of active voltage vectors with non-negative durations. Such a set of active vectors should be found in real-time and has to ensure a minimum number of transistor switching. This paper presents a simple and an effective SVM algorithm for five-phase Voltage-Source Inverters with the possibility to control independently the voltage vectors for fundamental and auxiliary orthogonal subspaces. The essential benefit is that output voltage is generated using only four active voltage vectors with limited numbers of switching. In the proposed solution, four active vectors are arbitrary chosen, independent of the positions of reference voltage vectors. The selected active vectors and the reference voltages are utilized only to calculate the on-time durations for transistors in any of the inverter phases. The selection of appropriate active voltage vectors, used to generate the inverter output voltage, is based on analysis of calculated durations. The proposed solution does not require any matrix inverting operation in the microprocessor. This makes the algorithm simple and efficient. The experimental results prove the proposed SVM strategy.