Boost-type power factor correction (PFC) rectifiers can be used in, for example, battery charging systems for Electric Vehicles (EVs). Conventionally available three-phase PFC rectifiers are limited to output 1/3 of the rated power when connected to a single-phase mains. This work presents the research into the single-phase operation of the Belgian rectifier, a novel boost-type PFC rectifier which allows for full power operation in both single- and three-phase operation (relevant for the three-wire split-phase systems in the USA with a maximum power of 19.2 kW). The single-phase AC-to-DC power converter is operated by paralleling and interleaving the three-phase rectifier bridge legs. By using the analysed triangular current mode (TCM) modulation scheme complete zero-voltage switching is achieved over the entire mains period. The power converter is further analysed with respect to the steady-state operation and component-level modelling. The modelling techniques are used to generate the Pareto-front of efficiency versus power density. The optimal design is selected based on the multi-objective requirements, and is a design with 6x interleaving with a boost inductance of 30µH that results in complete soft-switching transitions and achieves an efficiency of 98.42% with a power density of 5.34kW/dm3. After that, the single-phase Belgian rectifier is compared to the conventional six-switch boost PFC rectifier to identify and quantify the benefits. Finally, a closed-loop control model is proposed and implemented on the 19.2 kW, 1.5kW/dm3 hardware demonstrator for the conversion of a 240 V AC input with a maximum rms current of 80 A into a 380 V DC output to verify the single-phase operation of the Belgian PFC rectifier. Experimental results show efficiencies higher than 98% for power levels larger than 3kW.

Semiconductor lifetime and power density are considered to be two important development directions of power converter design in the future. Especially in some high dynamic application, the operation condition is changing frequently causing the temperature swing of semiconductor, and it leads to thermal expansion and contraction which affects the lifetime or reliability of semiconductor. A high maximum temperature or a large temperature swing leads to short lifetime. Meanwhile, high power density is a general trend. If the size of a whole system is limited, a high power density converter enables more functionality of the system. Also, high power density also leads to high portability. Works have been done to use interleaved and high switching frequency converter to get a high power density. However, those converters such as interleaved buck converter do not help to improve semiconductor reliability because it can only operate in synchronous conduction mode (SCM) and triangular current mode (TCM).

In this work, a $20kW$ DC/DC converter for highly dynamic application is designed. The four-switch buck-boost converter is chosen because of its flexibility and its possibility to get longer semiconductor lifetime and higher power density. It is possible to offer a free-wheeling interval in which no voltage is applied on the inductor, the transferred power can be regulated by adjusting the duty cycle of this interval. In addition, an optimal modulation scheme is proposed for this topology which further helps improve the reliability of semiconductor. An optimal power stage design is given which is a two-stage interleaved structure. Plus, a close-loop control strategy is given according to the design.

The proposed modulation scheme is tested with a low voltage level prototype, and the performance prediction is verified.

This research introduces the Prodrive-Select Rectifier, a novel three-phase buck-type power factor correction rectifier suitable for mains interfaced AC-to-DC conversion as, for example, can be found in on-board battery chargers for electric vehicles. The Prodrive-Select Rectifier shows excellent mains current total harmonic distortion, especially when interleaving of the converter branches is considered, and achieves competitive efficiencies by utilization of three-level buck circuits and a capacitive midpoint which allows for complete zero-voltage switching of the high-frequency power MOSFETs. In this work, two modulation schemes are proposed and analysed with regard to their zero-voltage switching capabilities. In addition, the complete converter analysis including steady-state analysis, transient closed-loop control and component-level volume and loss modelling is thoroughly described. In order to obtain an objective performance indication, the topology is compared to a state-of-the-art buck-type rectifier, namely the Swiss Rectifier. The proposed modelling techniques are implemented by means of a virtual prototyping routine yielding a Pareto-front in the power density versus efficiency performance space from which an optimal design is selected using multi-objective optimization. This Pareto-optimal design operates under partial soft-switching conditions and achieves a conversion efficiency of 98.3% at 2.9kW/dm3 power density. The modelling and optimization techniques are verified by an 11-kW, 1.3-kW/dm3 hardware demonstrator for conversion of a 400-V rms line-to-line AC input into a 400-V nominal DC output. Measurements show efficiencies higher than 97.5% in the range of 4kW- 11kW, with 97.7% peak efficiency and <4% total harmonic distortion at full power.