The increase in the average global temperature is a consequence of high greenhouse gas emissions. Therefore, using alternative energy carriers that can replace fossil fuels, especially for automotive applications, is of high importance. Introducing more electronics into an automotive battery pack provides more precise control and increases the available energy from the pack. Battery-integrated modular multilevel converters (BI-MMCs) have high efficiency, improved controllability, and better fault isolation capability. However, integrating the battery and inverter influences the maximum DC charging power. Therefore, the DC charging capabilities of 5 3-phase BI-MMCs for a 40-ton commercial vehicle designed for a maximum tractive power of 400 kW was investigated. Two continuous DC charging scenarios are considered for two cases: the first considers the total number of submodules during traction, and the second increases the total number of submodules to ensure a maximum DC charging voltage of 1250 V. The investigation shows that both DC charging scenarios have similar maximum power between 1 and 3 MW. Altering the number of submodules increases the maximum DC charging power at the cost of increased losses.

The automotive industry has grown considerably over the last century consequently increasing greenhouse gas emissions and thus contributing towards increase in the average global temperature. It is thus of paramount importance to increase the use of alternative energy sources. Electric vehicles have gained popularity over the last decade. However, a major concern with electric vehicles is their range. The range of an electric vehicle is limited by the battery pack, in particular, the weakest cell of the pack. One method of increasing the available energy from the battery pack is by introducing more electronics. Modular multilevel converters, with their modular concept, could be a viable solution. The concept of battery-integrated modular multilevel converters (BI-MMC) for automotive applications is explored. In particular, the impact of the number of cascaded cells per submodule is investigated, considering battery losses, DC-link capacitor losses, and the converter losses. Furthermore, an optimization of the DC-link capacitors and the selection of MOSFET switching frequency is presented in order to minimize the total losses.

This is a Swedish Licentiate's Thesis. Swedish postgraduate education leads to a Doctor's degree and/or Licentiate's degree.A Doctor's degree comprises 240 ECTS credits (4 years of full-time studies). A Licentiate's degree conprises 120 ECTS credits, of which atleast 60 ETCS credits constitute a Licentiate's thesis.