High Frequency Power Conversion Concepts for Transportation Electrification

Abstract

In this work, the theoretical realization and experimental verification of multiple high-frequency power conversion concepts for transportation electrification are developed. The two main types of electrical power converters in this research are high-frequency rectifiers and inverters with a focus on Level-3 fast chargers for electrical vehicles and multi-phase motor drives respectively. In the case of the high-frequency rectifiers discussed, the concept of Integrated Solid State Transformer (I-SST) is introduced as a high-frequency interface for the conventional multi-pulse diode rectifiers. It is shown that with the proposed modulation, the I-SST archives the elimination of low-frequency harmonics to comply with IEEE 519 standards. Moreover, output voltage and current regulation is now possible due to the proposed high-frequency modulation scheme. Similarly, an Active Neutral Point Clamp (ANPC) inverter concept is discussed in this research. The modulation approach proposed achieves a lower amount of loss dissipation compared to traditional approaches resulting in higher efficiencies and higher power density when compared to traditional approaches. The complete process of device selection for this converter is provided and an electrothermal analysis simulation is employed to compute the expected power losses in a 250 kW design example. In both cases, the use of wide band-gap devices is considered as the enabling technology to achieve a high-power density of each particular application by exploiting the fact that reduced-size magnetic components can be used when the switching operation of the converter is increased. The operational principle of each concept is thoroughly described through mathematical analysis which allows for a formal demonstration of the behavior of the converter and allows for the design of passive components such as input and output filters. Experimental results for each of the power converters introduced in this work are provided in scaled-down experimental prototypes with system powers ranging from 1kW to 5kW.