Modular multilevel converter with embedded battery cells for traction drives

Quraan, Mahran (2016). Modular multilevel converter with embedded battery cells for traction drives. University of Birmingham. Ph.D.

PDF - Accepted Version

Download (7MB)


This thesis proposes a new modular multilevel converter with embedded cell balancing for battery electric vehicles. In this topology, the battery cells are directly connected to the half-bridge choppers of the sub-modules, allowing the highest flexibility for the discharge and recharge of each individual cell. Tht: traditional battery management system is replaced by the control of the converter, which individually balances all the cells. A new balancing algorithm is presented and discussed in. the thesis, showing that the converter generates symmetric three-phase voltages with low harmonic distortion even for significantly unbalanced cells. The thesis also analyses stationary recharge of the battery cells from both three-phase and single-phase ac sources. The performance of the converter as a traction drive is assessed in terms of torque-speed characteristic and power losses for the full frequency range, including field weakening. A simplified model for estimating conduction and switching losses for the proposed modular multilevel converter is presented and the results for a typical driving cycle are compared with a traditional two-level converter. Simulation and experimental results on a kW-size prototype have confirmed the feasibility of the proposed traction modular converter in terms of effectiveness of the cell balancing control, validity of the proposed loss model, suitability of use for traction and effectiveness of recharging operations.

Type of Work: Thesis (Doctorates > Ph.D.)
Award Type: Doctorates > Ph.D.
College/Faculty: Colleges (2008 onwards) > College of Engineering & Physical Sciences
School or Department: School of Engineering, Department of Electronic, Electrical and Systems Engineering
Funders: Other
Other Funders: The University of Birmingham
Subjects: T Technology > TK Electrical engineering. Electronics Nuclear engineering
T Technology > TL Motor vehicles. Aeronautics. Astronautics


Request a Correction Request a Correction
View Item View Item


Downloads per month over past year