Johann W. Kolar

TL;DR: In this paper, the authors proposed an ECI control algorithm to tune the resonant frequency and to adjust the quality factor of the resonators of a 4-quadrant power converter.

Abstract: For developing and testing of power electronic converters and circuits, voltages and currents have to be measured to verify the proper mode of operation. In cascaded converters or multi-level topologies, the voltages to be measured contain common mode components up to several kV with transients up to several tens of kV/µs. Conventional isolated voltage measurement systems do either not meet the high voltage isolation requirements or exhibit a rather large coupling capacitance to ground. In combination with the high voltage transients, this coupling capacitance on the one hand impacts the circuit under test and on the other hand influences the voltage measurement. To reduce these effects, the coupling capacitance of the measurement system must be minimized. In this paper, a wireless voltage probe (WVP) is introduced to measure accurately on a high and transient reference voltage with minimal impact on the circuit under test. The basic concept and practical realization of the WVP are discussed and finally verified with measurements on a high power medium voltage IGBT converter system.

TL;DR: In this paper, the construction of a lateral stator machine merged into a test bench is described, which is used for measuring the standstill torque of the machine in a configuration without bearings, such that only the electromagnetic torque is measured.

TL;DR: In this article, the authors proposed a 24pulse three-phase diode rectifier by means of a simple and unique topology, the topology and operating principle are shown and the performance and the practicability are validated through experiments.

TL;DR: In this article, a synergetic control structure for a two-stage three-phase boost PFC rectifier with subsequent DC/DC buck stage was proposed, which allows to only switch one out of the three rectifier bridge legs, leading to switching loss savings of over 66 %.