Design of Complex Vector Controller for High-Power Induction Machine Drive

In high-power drives of large commercial vehicles, the switching frequency of the inverter is always strictly limited to avoid high switching losses. In this article, a high-performance complex vector controller in discrete domain is proposed to reduce the cross-coupling effect and improve control performance under low switching frequency. The discretization error of the induction motor model under different coordinate systems is explored, and a high-precision discrete induction motor model is proposed for the design of the complex vector controller and flux observer. To improve the dynamic response of the rotor flux linkage, the designed controller takes the current as the inner loop and the rotor flux linkage as the outer loop. Besides, the signal reconstruction strategy is proposed to solve the contradiction between the variable-step characteristics caused by synchronous modulation and the discretization process based on constant step size. Finally, the designed control strategy and analysis of the system are validly verified by simulation and experimental results.