纯电动汽车充电机系统稳定性研究

一般纯电动汽车充电机的控制系统基于额定输入电压、充电电流等条件设计,忽略了工作条件变化和元器件寄生参数对系统稳定性的影响.为了保证在充电过程中充电机能够稳定工作和进一步了解充电机系统稳定性的机理,建立基于全桥拓扑结构的纯电动汽车充电机的平均线性小信号模型.依据该线性小信号模型推导出表征充电机特性的关键传递函数.通过MATLAB仿真,研究纯电动汽车充电机在拓扑结构和主要参数确定的情况下,影响其控制环路特性的因素如输入电压、充电电流、输出滤波器等效串联电阻与表征控制环路特性的参数如穿越频率和相位裕度之间的关系,并用实验证明了理论分析的正确性.

System stability of battery charger for battery electric vehicle

The battery charger control system for battery electric vehicle is designed according to the conditions of rated input voltage and charging current.The influences of working condition change and components’ parasitic parameters on the system stability are always ignored.In order to guarantee the stable work of battery charger under all conditions and further understand the mechanism of system stability,its average linear small-signal model is established based on the full-bridge topological structure and the key transfer function is deduced to represent its characteristics.MATLAB simulation is carried out to study the relation between the influencing factors of control loop characteristics when the topology and parameters of charger are fixed,such as the input voltage,charging current and equivalent series resistance of output filter,and the representing parameters of control loop characteristics,such as the crossover frequency and phase margin.Experimental results show the correctness of theoretical analysis.