Development and testing of a high-country electric vehicle. (2022)
Type of ContentTheses / Dissertations
Thesis DisciplineElectrical Engineering
Degree NameMaster of Engineering
HiCEV (High-Country Electric Vehicle), is an electric vehicle conversion project which aims to produce a prototype to test the viability of replacing traditional internal combustion engine (ICE) powered farm vehicles with those having an electric drivetrain. Previous work has been performed on a 70- series Land Cruiser, replacing the existing ICE system with an electric motor and power-train. The project was taken over, by the author, as vehicle hardware was largely pre-installed in the vehicle; however, due to the presence of several faults, most significantly, in the electric vehicle control module (EVCM), significant redesign, rewiring, and reprogramming was required to enable vehicle functionality.
Modifications were made to the vehicle to facilitate operating without the EVCM, using the built-in motor control within the inverter. This had the secondary effect of reducing the complexity of the systems, by reducing the number of I/O pins available for switching and monitoring several of the vehicle sub-systems. To work around the EVCM, the inverter took input from several peripherals within the vehicle as well as receiving information from the Battery Management System (BMS), through CAN bus communication.
Testing on HiCEV was carried out to establish the operation of the vehicle, and how it relates to both theory as well as the project objectives. It became evident early on in testing that due to the cell tap wiring in the BMS, the vehicle was being shut down as a result of high measured internal resistances within cells. To enable further testing on the vehicle, the capacity for the BMS to shut down the vehicle was bypassed. Testing yielded that motor and inverter characteristics largely resembled the expected theoretical outcomes, with the motor accomplishing peak torque outputs of 320 Nm at lower vehicle speeds with the torque output beginning to lower at 3600 rpm. The motor and inverter configuration ended up accomplishing a peak power of 130 kW, noticeably greater than the original 95 kW produced by the previous power systems; considerably, due to the torque availability at lower speeds, producing a noticeably greater acceleration than most ICE vehicles. Further testing on specific cells within the pack did yield that there were early signs of degradation, which may inhibit long term reliability; in most cells, signs of degradation were expected and minimal given the age of the cells in the vehicle, which is close to 10 years.
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Hennessy, Pierce L. (University of Canterbury, 2016)The development of a High Country Electric Vehicle has come about in response to a farmers desire to reduce the dependence on fossil fuels on his station. Electric vehicles have become more prominent in the urban commuter ...
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