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The paper deals with real-time estimation of the junction temperature of a SiC power MOSFET modules. The junction temperature of one device of the module is real-time estimated by measuring its current and on-state voltage at each time sample, and entering the temperature model of the device. The temperature model is obtained in a dedicated commissioning session, where the vON is measured at different temperature and current conditions. A sequence of current pulses of short duration is closed-loop imposed to the device at different values of the measured DBC substrate temperature, so that the temperature measurement is consistently representing the junction temperature during the identification. The presented results show that the proposed method permits on-line temperature monitoring and even closed loop regulation of the junction temperature of the tested SiC power MOSFET modules. Different module from two different manufacturers are tested under realistic operating conditions. This concept can be usefully applied to all DC/AC conversion structures, where the monitoring of one device can be of reference value for the entire module.

The compensation of converters' nonlinear voltage error is crucial in encoder-less control of ac motor drives. In this paper, a new self-commissioning and compensation method is proposed for matrix converters (MC). Similar to what done in the past for voltage source inverters, the MC voltage error is identified before the drive start and stored in a look-up table (LUT), later used for error compensation and accurate voltage estimate. Different from what observed in the past, the effect of parasitic capacitors on nonlinear voltage error of MCs in four-step current based commutation is observed and studied. Eventually, this method is applied to the sensorless control of a synchronous reluctance (SyR) motor drive, using the direct flux vector control (DFVC) concept. Experimental results are presented to validate the effectiveness of proposed self-commissioning in improving the performance of sensorless control at standstill and low speed.

SiC power MOSFETs are an advancement in the power electronics technology today available on the market. Respect to Si-based power devices, they offer potential for higher operating temperatures, higher breakdown voltage with low onstate resistance, and lower switching losses permitting much higher switching frequencies. To date, the attempts to apply the SiC power devices to the field of AC drives are relented by the high price of such new devices and by the challenges related to electromagnetic compatibility and reliability. A new test rig is proposed, built for comprehensively testing SiC power MOSFET modules in real operating conditions, using off-the-shelf hardware. The presented results focus on the evaluation of onresistance as a function of drain current and junction temperature, and on dv/dt evaluation as a function of external gate resistance. Different modules are tested, custom realized using SiC MOSFET dies by two leading manufacturers. Finally, a new methodology for on-line estimation of the devices junction temperature is presented.

This paper presents a sensorless control technique based on direct flux vector control (DFVC) method for synchronous reluctance (SyR) motor drives fed by a three-phase to three-phase matrix converter (MC). Rotor position is estimated based on active flux (AF) concept down to 50 [rpm]. Furthermore, the effect of nonlinear voltage errors of the MC is compensated, and a self-commissioning method capable of identifying the voltage error before compensation is presented and tested. The proposed drive combines the advantages of matrix converters and SyR motors in sensorless fashion, for application into a number of fields, spanning from compact drives for aviation to line-supplied drives for industry applications. Experimental results are provided to prove the feasibility of the proposed technique.

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