Experimental Verification of Deep Field Weakening Operation of a 50-kW IPM Machine by Using Single Current Regulator

This paper analyzes critical control issues associated with the deep field weakening operation of interior permanent magnet (IPM) synchronous machines. The singlecurrent-regulator control algorithm is reviewed, 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
q
-axis voltage for variable-speed and variable-load conditions. The control algorithm is implemented on a 50-kW IPM machine. Test results, including 7:1 constant power speed ratio operation, are presented to verify the theoretical analysis.