Hybridized Space-Vector Pulsewidth Modulation for Multiphase Two-Level Voltage Source Inverter

In space vector pulsewidth modulation (SVPWM) algorithms for multiphase two-level voltage source inverters (VSI), the components of active vectors in all orthogonal spaces have to be calculated within the processor and stored in its memory. These necessitate intensive computational efforts of the processor and large memory space. This article presents a hybridized SVPWM for multiphase two-level VSI. In this algorithm, elements of the vector coefficient inverse matrix are calculated once outside the inverter processor and treated as constant values; this reduces the computational efforts of the processor and memory space. This scheme reverses the computational steps used in classical SVPWM. Arbitrarily pre-selected active vectors (for any position and amplitude of the reference vectors) with durations determined using classical SVPWM concept are utilized. The durations of switching vectors are analyzed and the switching sequences in individual inverter phases are optimized to reduce the number of commutations. This approach demonstrates that resignation from classical analytical method in multiphase two-level VSI enables the creation of simplified modulation algorithm. This modulation strategy enables an independent generation of multiple output voltage vectors with independent rotating speed, lengths, and positions. Experimental validation of the algorithm was carried out on two-level five-phase VSI with RL load.