Experimental verification of deep flux-weakening operation of a 50 kW IPM machine by using single current regulator

This paper analyzes critical control issues associated with the deep flux-weakening operation of interior permanent magnet (IPM) synchronous machines. Then we review the single-current-regulator control algorithm which controls the d-axis current actively and gives a fixed q-axis voltage command. To achieve better operational efficiency and performance, improvements are made to choose an optimal qaxis voltage for variable speeds and loads. The control algorithm is implemented on a 50 kW IPM machine. Test results available to date including 7:1 constant power speed ratio (CPSR) operation are presented to verify the theoretical analysis.