Performance improvement of ultra-high-speed PMSM drive system based on DTC by using SiC inverter

Abstract

This paper examines the control performance of a permanent magnet synchronous motor drive system based on direct torque control (DTC) using a SiC-MOSFET inverter (SiC inverter). The dead-time of the inverter affects the performance of the motor control. In high-speed drives, the dead-time effect increases because the control period becomes shorter. By using a SiC inverter for which the switching speed is faster than that of the Si-IGBT inverter, the dead-time can be shortened, and performance improvement of the control is expected. This paper also proposes a sensorless starting method using DTC.It is difficult to start the motor in a drive system without a position sensor. In the conventional ultra-high-speed drive using DTC, the motor is started by open-loop control. Experiments reveal the effectiveness of using a SiC inverter and shortening the dead-time.In addition, the experimental results reveal the applicability of the proposed starting method.

Implementation and Experimental Validation of Ultrahigh-Speed PMSM Sensorless Control by Means of Extended Kalman Filter

“…The switching frequency was chosen to 40kHz, in order to be able to drive a maximum electrical frequency of 4kHz (corresponding to 240krpm for a 2-pole motor). In [5] the performance improvements of a SiCinverter with respect to an inverter with conventional Si-IGBTs are listed. Among them the faster switching speed and the shorter dead-time can be emphasized, resulting in performance improvements due to lower THDi of the phase currents and less influence of the inverter nonlinearities, respectively.…”

“…The instants of measurement of the phase currents, representing the two states iand i -(see ( 1)) define the calculation periods in which the di erence equation ( 5) holds. The second addend in (5) represents the external input to the system during the calculation period. As can be immediately seen in Fig.…”

“…However, while many studies propose sensor-less control speed schemes for low and medium speed PMSM, [1]- [4] among others, only few publications report drives in ultra-high speed regions. The application is challenging for the control scheme in terms of control accuracy [5] and computational time of the implementation [6], [7]. In the ultra-high speed operation also e ects such as the iron losses [8], [9] and the non-linearities of the inverter due to dead times in the switching patterns [5] outweigh more than in the low-speed region and have to be considered and compensated.…”

“…Due to this facts, other sensor-less control techniques for the ultra-high speed region have been generally used, such as open loop constant V/f or I/f techniques [11], DTC [5], adaptive control [10], [12]. More recently, also the Kalman filter has been considered in this application [13]- [15].…”

Optimization of thermal management and power density of small-scale wind turbine applications using SiC-MOSFETs

“…[4] demonstrated the impact of SiC technology in energy storage integrated solid state transformer, higher power cell efficiency and lower battery losses are achieved at high switching frequency. [5] stated that SiC converters could improve the control performance of the motor high speed drive system by decreasing the voltage error due to the dead time is reduced. However, few work has been done on the impact of SiC technology in small-scale wind energy.…”