Development And Research Of Vehicle Controller For Extended-Range Fuel Cell Bus

With growing concerns on energy crises and environmental issues, protonexchange membrane fuel cell (PEMFC) hybrid buses are favored by governments andautomotive industry because of zero emission, high efficiency and low noise.Extended-range fuel cell buses can be charged from charging posts and they areespecially suitable for city bus road conditions. The VCU coordinates the work of thecomponents in the powertrain, and influences vehicle safety, power performance andfuel economy greatly. Supported by the "National863Program Fuel Cell Bus Project",in this dissertation a new generation of VCU has been designed, a full-automatic codegeneration technology has been developed and an optimal vehicle control strategy hasbeen studied.Firstly, the configuration and parameters are selected for extended-range fuel cellbus powertrain system. In order to achieve better control performance, new generationof VCU using Freescale32-bit MPC5644A as the digital core has been designed,including circuit diagram designing and PCB plate making. For the complicatedcommunication network, TTCAN protocol is used to ensure the accuracy and real-timeof CAN bus.Secondly, a full-automatic code generation platform technology has beendeveloped for the sake of short research period and high code quality, which is designedfor embedded target system based on MATLAB/Simulink environment. It is capable toconvert both control algorithm blocks and hardware drivers’ blocks into executablecode and fulfill compilation, link, download all accomplished automatically.Full-automatic code generation technology has been validated in test bench and appliedto develop the new generation of VCU.Thirdly, vehicle control strategy and energy management for extended-range fuelcell bus has been studied. Considering the liability and durability of the fuel cell,constant-current control method is selected and optimal powertrain control algorithms,such as electric motor average power prediction, DC/DC convertor current closed loopcontrol and fuel cell current/voltage compensation, are studied on this basis. Aiming atbest vehicle fuel economy, energy management research compares and analyzes battery charge-depletion charge-sustenance, blended and dynamic programming strategies invehicle performance and running cost. Simulation results show that the extended-rangefuel cell bus achieves the minimal running cost under DP strategy and the SOC line isclose to CDCS strategy. In ten Chinese city bus cycles, extended-range fuel cell busconsumes2.63kg hydrogen,58.10kW· h electric energy, costs￥136.86andequivalent fuel consumption of100km is25.28L, which saves10.42%fuel comparingto the powertrain configuration using diesel engine.