In this paper, the short-circuit (SC) performance of two different SiC MOSFETs is experimentally investigated for different input voltages, biasing voltages and case temperatures. The measurement results are compared to simulations, and a good agreement is achieved. For fault handling, two different overcurrent protection (OCP) circuits are designed and applied to the SiC MOSFETs. The desaturation method is successfully tested with a hardware solution substituting the blanking time delay. The second method is based on sensing the voltage drop across the parasitic inductance at the source pin. The experimental and simulation results show that both OCP methods have the capability to detect a short circuit condition in the SiC MOSFET within safe SC time avoiding device failure.

A short-circuit e.g. in a half-bridge converter is a severe and potentially destructive operation condition for a power transistor and needs to be turned-off quickly and safely. In order to define strategies how to improve the reliability of a power device, it is necessary to understand the failure dynamics during a short-circuit. In this paper, an experimental study focussing on the short-circuit capability of different types of 600V power transistors based on Si, SiC and GaN is presented. Usually, a 10μ8 short-circuit withstand time at 400V is required for 600V power transistors. Measurement results show that the investigated Si and SiC MOSFETs can withstand short-circuit times up to 13μs at 400V and 150°C, while the normally-off and cascode GaN devices demonstrate considerably less withstand capability.

In this work, the static and dynamic characteristics of a new double-trench SiC MOSFET are experimentally investigated and compared to two different available commercial SiC MOSFETs. The SiC devices are applied in a ZVZCS Phase-Shifted Full-Bridge converter which uses the parasitic leakage inductance of the transformer to achieve soft switching. A practical method to break down the converter losses based on separating the measured semiconductor and magnetic losses is proposed and compared to an analytical loss model. The experimental results show several advantages of using SiC MOSFETs as well as ZVZCS in the converter. The main results can be summarized as elimination of the freewheeling circulating current mode, clamping the overshoot voltage across the rectifier diodes and achieving soft switching in a wide power load range without additional auxiliary circuits or resonant inductor. Experimental results for a 10kW, (100–250) kHz prototype show an efficiency of up to 98,1% for the whole converter.

This paper focuses on the performance analysis, modeling, and control of permanent magnet synchronous generator (PMSG)-based wind energy conversion. This work analyzes controllers for the machine-side converter (MSC) and grid-side converter (GSC) and presents a new direct torque control (DTC) scheme based on a 12-sectors polygonal DTC for variable speed control of the PMSG. The proposed method solves the drawbacks faced by conventional six-sectors DTC control. The proposed method utilizes 12 sectors of 30° each compared to 60° in the conventional 6-sectors DTC. The 12-sectors technique was applied to voltages and flux vectors to increase the degrees of freedom for the selection of optimal vectors and, thus, reduce the torque ripple. This work analyzed the aforementioned DTC methods using MATLAB/Simulink, comparing the dynamic response of the proposed 12-sectors DTC with the conventional 6-sectors DTC control, and the results verified the effectiveness of the proposed DTC control.

The reverse recovery characteristics of the body diodes of planar and double-trench SiC MOSFETs are experimentally analyzed in switching tests and compared. The body diode of the trench SiC MOSFET shows improved performance, so that using an anti-parallel SBD to suppress the reverse recovery behavior becomes unnecessary. Following the switching tests, the devices are operated in continuous mode in a 10kW / 100-250 kHz buck converter. The measured efficiency of the whole converter is up to 98.9% in synchronous rectification mode. Parallel operation of the considered planar MOSFETs is needed in the converter. Therefore, the impact of parameter mismatch on the static and dynamic current sharing of the transistors is evaluated, showing that paralleling of SiC MOSFETs is feasible. The performance of the parallel connection is temperature dependend. Based on the measured and analytically calculated losses, the junction temperature is estimated to ensure the safe operation area of the parallel SiC devices in continuous operation mode.

In electric drive control systems, the main goal is to maintain the driving motor speed to meet the mechanism’s requirements. In some practical industrial applications the mechanically-coupled load to the motor shaft has a varying mass during the system operation. Therefore, the change of mass changes the value of the moment of inertia of the system. The moment of inertia impacts the system operation, particularly the transient performance. Therefore, the variation of moment of inertia on the motor shaft during its operation creates additional challenges to accomplish a high-quality speed control. The main purpose of the current work is to study the impact of the variation of moment of inertia on the performance of both AC and DC electric drive control systems and to make a comparison between them. A mathematical analysis and simulations of the control system models had been presented; one time with three-phase induction motor and another time with DC motor, both with variable moment of inertia. A simulation of both systems had been accomplished using the Simulink software in MATLAB. The simulation results of operation of these systems have been analysed in order to get useful conclusions and recommendations for the electric drive control system designer.