Analysis and design of IPMSM drive system based on visualization technique in discrete time domain

The performance of interior permanent magnet synchronous motor (IPMSM) drive system is affected by parameters variation and digital control delay, which increases the difficulty and complexity of analyzing and designing, a visualization technique is proposed in discrete time domain. First of all, D-partition method is used to obtain stable region of IPMSM current loop, while the sampling & computation delay and pulse width modulation (PWM) delay are considered. Then the effects of speed, inductance, resistance, dc-link voltage and switching frequency on stability are analyzed, and stable region area (SRA) is put forward as an index of these effects. Furthermore, a gain-phase margin tester is used to get the gain margin and phase margin curves. A desired margin region is derived, and parameters optional region is obtained while taking parameters variation into consideration. Finally, according to the 3D graphic of bandwidth, an optimal set of PI parameters is chosen from the parameters optional region. Experimental results prove out the validity and feasibility of the proposed technique.