Projects:2017s1-180 All Electric Vehicle for City Use

Aims

The Aim of this project is to take a 1993 Mazda MX5 that has been partially converted into an electric vehicle and take existing subsystems and design and develop the remaining subsystems needed in order to create a road ready all electric vehicle.

Objectives

- Design and Integrate a Higher Voltage Battery System incorporating an Arduino based PWM Feedback controlled Boost Converter
- Design and Integrate an Auxiliary Charging System
- Design and Integrate a charging system for the main batteries
- Design and Integrate a Power Electronics Enclosure which incorporates a liquid cooling system for the Inverter and Boost Converter
- Design and Integrate an Arduino based Driver Display

Results / Implementations

Battery System
- Our group was provided with Pylon-Tech Extra 2000 Modules, Each capable of providing 48 V, 50 A, 2.4 kWh
- Were designed to be only connected in parallel, therefore we designed the system to use 3 Battery modules so we had a system capable of providing 150 A with 7.2 kWh available for use

Feedback Controlled Boost Converter
- Designed to increase battery voltage of 50 V to 210 V
-converter control module consists of voltage and currents sensors, a programmed Arduino microcontroller to produce a Pulse width modulation signal.
-The arduino take input from sensors measuring IN/OUT voltage adn current, then compare instantaneous voltage with 210V to increase or decrease duty cycle of the PWM signal, hence maintain the average output voltage of the boost converter to be 210V, providing a potential for the motor operation.

Auxiliary Battery Charging System
- In an Electric vehicle, the there is no alternator so a DC/DC Converter is used to constantly charge the 12 V battery used to power all vehicle headlights, accessories, control systems and safety systems. If this battery dies during transit then the vehicle will not be able to operate.

- Our system design consists of 4 modules, a 200W DC/DC Buck Converter that steps down the output of the Main batteries, a contactor that only closes when the vehicle is turned on and a current monitoring module.

- The system turns on when the ignition key is turned to the ON position, the battery then charges while the vehicle is operating and only stops charging when full. A current sensing module is used to monitor the current being used by the auxiliary system to ensure systems are not under stress

Charging System
- The pylon-tech battery modules each accept a maximum charging current of 50A
- It then raised the question of whether these batteries will draw as much as 50A when the batteries are at a low charge
- Discharging the batteries to an appropriate amount and then connecting to a constant current power supply, always saw the batteries charging as much as they could
- This therefore verified that the battery modules will draw whatever current they require
- A solution to this consisted of using large portable power supplies but as there are 3 batteries, this means our battery system potentially could draw 150 A to charge

- A recommendation was made to purchase a constant current charging module that can distribute the current across 3 modules without the concern for it drawing too much current

Driver Display

- A driver display was developed because a driver needs to know how far their electric vehicle can travel, this display has been designed to show the voltage of the main battery, the auxiliary battery and the current draw of the auxiliary battery

- A 40x4 New haven White Back lit Display was selected and a 3D mounted bracket suiting the open space in the Mx5 dash was created - The display is controlled by an Arduino Uno and is designed to read data directly from Transducers and Voltage sensors

Group Members

Mohamed Salem

Shujun Wang

Group Supervisors

Associate Professor Nesimi Ertugrul

Dr Said Al-Sarawi