Experimental Assessment of Motor Core Loss, Inverter Loss and Ringing Phenomenon Under SiC-MOSFET Inverter Excitation

This study investigates the characteristics of core loss of the interior permanent magnet synchronous motor (IPMSM)and inverter loss under the silicon carbide (SiC) MOSFET inverter excitation in various experiments; the IPMSM system under the SiC-MOSFET inverter excitation is tested with two different control methods. First, the SiC-MOSFET inverter is controlled by the pulse-width modulation (PWM)method with a fixed DC-link voltage, very high voltage modulation index of 1.1 and carrier frequency of 10 kHz and 20 kHz; the ringing phenomenon happens in motor voltage in this case, which causes high-frequency harmonics significantly. Then, as an alternative way to reduce the harmonics caused by the ringing phenomenon, the pulse-amplitude modulation (PAM)control technique with an automatically-adjusted DC-link voltage and 120° excitation angle is applied to drive the SiC-MOSFET inverter; this test has never been considered before. In addition, experimental results of motor core loss and inverter loss obtained with the SiC-MOSFET inverter are compared to the results obtained with another silicon (Si)IGBT inverter at same operational conditions for evaluation purpose. The motor rotational speed is also varied in experiments. Furthermore, measured motor voltage and current waveforms and total harmonic distortion (THD) values under the two inverter excitations are analyzed.