A Computationally Efficient Carrier-Based PWM Strategy for Asymmetrical Six-Phase Motor Drive of Electric Vehicle with Unified Zero-Sequence Signal

The number of space voltage vectors is exponential growth with the phase increase of the voltage source inverter, which leads to the inverter-fed asymmetrical six-phase motor (ASPM) with abundant voltage vectors, and drastically increases the complexity of space-vector modulation. By comprehensively analyzing the principle of widespread four-dimensional space-vector modulation for ASPM, the feasibility of a simplified zero-sequence signal with unified expression is proved, and the unified zero-sequence signal is deduced which builds the equivalent relationship between space-vector modulation and the proposed carrier-based modulation. Thus, the optimized carrier-based modulation with computational efficiency and low resource occupancy can be derived which can avoid the complex process of space-vector modulation. The feasibility, equivalence, and simplification of the proposal are proved by simulations and experiments, and the calculation burden and resource occupancy are reduced.