Design and Control Method for Interior Permanent Magnet Synchronous Machine Drive With Capacitor Power Network

This article proposes a method to extend the operating area of the interior permanent magnet synchronous machines (IPMSMs). In general, the power factor (PF) of the voltage source inverter becomes lower to maintain the maximum torque per ampere (MTPA) current of the motor. Therefore, the voltage–ampere (VA) capacity of the inverter is not fully utilized. In order to maximize the VA capacity utilization of the inverter, the capacitor network is proposed, which is located between the motor and the inverter. The PF of the inverter increases, as the capacitive impedance of the network cancels the inductive motor impedance. In this way, the maximum speed of the constant torque region increases without changing the inverter and the motor. Due to the capacitor network, this method generates a higher power than the conventional drive method. The design method and analysis results of the capacitor network are presented. The current control method in the proposed system is also presented. At the end of this article, the effectiveness of the proposed system is verified through the experimental results.