Electric Vehicle Battery Charging and Low Voltage Grid Implications

Abstract

In recent years, concerns over global warming and climate change have spurred on the research and development of the electric car. With manufacturers such as Nissan, Renault, Tesla and more producing affordable and effective automotive solutions, the public perception of electric vehicles has changed and there are now around 80,000 vehicles on the road in the UK alone. However, the uptake of electric vans and delivery vehicles has been much slower, in part due to manufacturers focusing on the non-commercial vehicle. With this, electric van technology is largely, behind. With 4 million vans on the UKs roads, as well as other large vehicles such as busses and trucks, represents a significant portion of all vehicles that remain non electrified and therefore prime candidates for electrification. The next five years will see a substantial increase in the number of all-electric (EVs) and hybrid electric vehicles (HEVs) utilizing on-board electrochemical energy storage devices (batteries) that require full or part recharging by connection to a low voltage utility network that supply domestic or light industrial users. The utility connection requires a battery charger composed of a uni- or bi-directional power electronic converter that converts the AC supply to DC or vice versa. For larger vehicles higher energy/power is required and thus a number of batteries may have to be connected in parallel to obtain the required energy levels or satisfy the peak power demands, or simply to improve the fault tolerance capacity due to the technical challenges associated with the assembly and management of large (electro-chemical) cell structures. The expectation for future automotive power electronic converter products is lifetimes of 10 years and over, and operation in arduous temperature environments, factors that compromise existing power converter topologies, in particular those employing electrolytic capacitors. This thesis discusses a novel 9kW battery charger design that is modular, has a balanced three-phase input, is near unity power factor and has no electrolytic capacitors. Several key areas are discussed, analysed through calculations, simulations and then constructed and validated through test results.

Date of Award	31 Dec 2017
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Roger Shuttleworth (Supervisor) & Sinisa Durovic (Supervisor)