Papers by Author: Cheng Ning Zhang

Abstract: A novel drive system the Dual Motors Coupling Propulsion (DMCP) for battery electric buses was proposed, and its structure and working principle were introduced. For the power and comfort performance of the vehicle, the control method of the motors and the coordinated control strategy of the DMCP were developed. The co-simulation platform of AMESim and Simulink was established, based on which the dynamic model of the vehicle equipped the DMCP was built. The simulation results show that the DMCP runs smoothly in the Chinese typical city bus driving schedule. This indicates that the control strategy can manipulate the DMCP to drive the bus powerfully and smoothly. This has laid the foundation of the further research of the DMCP.

Abstract: Due to the inconsistency of the lithium-ion battery pack, the active balance method based on multi-secondary coaxial-winding transformer was introduced. The control principle of the balance system was analyzed, and the energy transfer process was explained. A balance system model was established by using MATLAB/Simulink, including battery model, transformer model and SOC calculate model. The duty cycle and the frequency of the MOSFET in the primary and second side of the transformer were studied to work out the balance system control strategy. According to the simulation results, multi-secondary coaxial-winding transformer can be used to balance the batteries’ voltages, and the energy losses can be reduced by choosing high-frequency transformer.

Abstract: The 2-D time-stepping finite element method is adopted to systematically analyze the effect of DC supply voltage of inverter on eddy current loss in permanent magnet of PMSM for EV application. The finite element model and inverter model are built to calculate the winding currents, eddy current losses in permanent magnet and air-gap flux densities with different DC supply voltages when the motor runs in flux-weakening area. Analysis shows that, the eddy current increases significantly with the increase of DC supply voltage, although the fundamental winding current decreases. The temperature-rise experiment of permanent magnet is carried out, proving the validity of analysis.

Abstract: Both the performance and lifetime of battery pack are substantially reduced in the cold temperatures, and it influences the performance and cost of electric vehicle strongly. Reasonable and effective heating system becomes very critical for solving the problem. This paper introduces the research development of heating system in the world, including the primary cause of the poor performance of battery pack at cold temperatures and heating of batteries, analyses the methods of heating that have been used or are researching. The limitation of current heating systems is pointed out for the future research.