Improvement of drive range, acceleration and deceleration performance in an electric vehicle propulsion system

This paper presents technologies that will be employed in a battery electric vehicle, aiming at improving the vehicle drive range, acceleration and deceleration performance and reducing the cost. Firstly it discusses a short-term power management scheme employing a high-power-density ultracapacitor bank to load level a high-energy-density, cost-effective but low-power-density Zn-Br battery for satisfactory overall performance of the vehicle power source. Then it looks at the issue of constant power operation of a BDCM propulsion system. A novel multifunctional DC-DC converter topology has been proposed for both short-term power management and the constant power operation of the BDCM propulsion system. It features simple circuitry, high efficiency, and low cost. Analysis of the operation principles of the multifunctional DC-DC converter is given. Control methods of regenerative braking of a BDCM at different operation modes are especially addressed.