Dae-Hyun Cho, Seok-Min Kim, and Kyo-Beum Lee, "Neutral-Point Voltage Ripple Reduction of High Frequency Injection Sensorless Control of IPMSM Fed by a Three-Level Inverter," Journal of Institute of Korean Electrical and Electronics Engineers, vol. 24, no. > Paper

This paper proposes a neutral-point voltage ripple reduction of high frequency injection sensorless control of IPMSM fed by a

three-level inverter. The high frequency voltage injection method has been successfully applied to sensorless control for IPMSM at

low speed region. In the process of high frequency voltage injection sensorless control for IPMSM, the neutral-point voltage ripple

is increased. It should be reduced because it distorts the output current and decreases a lifetime of DC-link capacitor. The

proposed method in this paper reduces the neutral-point voltage ripple by compensating the reference voltage, and the

compensation value is calculated simply with reference voltages and currents. The effectiveness of the proposed method is verified

by simulation results.