针对传统温度控制策略在水冷型质子交换膜燃料电池(proton exchange membrane fuel cell,PEMFC)工作中水泵和散热器风扇存在的强耦合性,并为了提高电堆的工作性能和寿命,提出一种流量跟随电流的温度控制策略,根据电堆电流变化调节冷却水流量来控制电堆冷却水进出口温差,通过PID控制器调节散热风扇控制电堆入口温度。在水冷PEMFC热管理平台上对传统控制策略、流量跟随控制策略做了实验对比。结果表明,流量跟随电流控制策略使冷却水出口温度最大超调量减少64.3%,冷却水出入口温差最大偏差减少46.7%,调整时间平均缩短73 s,达到了较高的控制精度和响应速度,削弱了水泵和散热风扇的强耦合作用,流量跟随电流控制策略能够满足PEMFC系统对温度控制的要求。
For the strong coupling problem that exists in the operation process of a water-cooled proton exchange membrane fuel cell(PEMFC) and to improve the performance and life of the PEMFC, a temperature control strategy for flow-following-current was proposed, this strategy regulates the coolant flow based on the current value thereby controls the temperature difference between the coolant inlet and outlet of a stack, the PID controller controls the inlet temperature of coolant by regulating the rotational speed of the radiator fan. Due to the different changes of current and power in the dynamic operation process of PEMFC, the system temperature changes in flow-following-current and power were needed to research respectively. Comparative experiments between the traditional control strategy and the flow following strategy were made on a test platform for the thermal management of the PEMFC. The results show that when compared with the traditional control strategy, the flow-following-current strategy could reduce the maximum overshoot of the coolant outlet temperature by 64.3% and decrease the maximum difference between the coolant inlet and outlet temperatures by 46.7%,the response time of system was reduced by 73 s at least. Besides the temperature changes were more stable in the flow-following-current compared to the flow-following-power. The flow-following-current strategy has realized a higher control precision and response speed, strong coupling between radiator fan and water pump can be effectively weakened, a short-term heating also can be avoided inside the stack when the current is greatly increased. The flow-following-current strategy can well meet the requirements on the temperature control of fuel cell systems.