Design, development, and control of an off-road hybrid electric vehicle power system

Abstract

With global warming and climate change threatening the planet, the auto industry is transitioning from conventional internal combustion engines to electrical power trains. Globally, electric vehicles and hybrid electric vehicles are becoming popular with 10 million cars sold in 2022. Electrification is not limited to the personal cars and public transport, but includes applications in transportation, mining, and military. The power system and battery pack are the main components of electric and hybrid electric vehicles. Battery pack capacity and performance affect the overall mileage. This thesis models and sizes the battery pack based on the mechanical and electrical specifications of the vehicle. The control algorithm is the heart of an unmanned, remote controlled, electric vehicle. This work presents a combined control strategy for an unmanned hybrid electric vehicle using a Joystick. The control algorithm consists of a dynamic controller designed using the mechanical modeling of the vehicle combined with an electrical control strategy known as Field Oriented Control. The proposed technique generates the torque and speed signals using dynamic model of the vehicle and trajectories applied to the model. These signals are then utilized by the inverter controller in the vehicle's power system. The proposed algorithm generates excellent results based on trajectory following and can guarantee the safe operation of the battery pack without over discharging the battery higher than its nominal discharge rate to provide longer lifespan during harsh operations. The simulation results show that the vehicle can operate in different road conditions without violating the discharge limit of the battery pack, while following the input trajectories. The highest discharge currents are associated with the toughest road conditions and shorter terminal time during which the vehicle should reach the desired speed applied through the trajectories. The proposed control algorithm can be applied to other vehicular application by taking their specific mechanical behaviors and characteristics into account. Keywords: electric vehicle, hybrid electric vehicle, power system, battery pack, field oriented control, dynamic modeling