汽车用电磁液冷缓速器控制系统设计

Design on Vehicle Electromagnetic Liquid Cooling Retarder Controller

电磁液冷缓速器具有功率密度高、持续制动热衰退小的优点,在载重汽车上逐步得到推广。利用多个IGBT并联驱动励磁线圈,多个二极管并联续流,温度传感器检测冷却水温度,温度开关检测电路板温度,电磁继电器作为电路板热保护器件,4档换挡手柄作为换挡信号输入元件,利用MC9S12XS128MAA单片机作为控制系统CPU,进行电磁液冷缓速器控制系统设计。实车实测表明:当蓄电池端电压为24.6 V,IGBT开关频率为100 Hz,在1、2、3档模式下,驱动励磁线圈的IGBT占空比分别为1/3、2/3、3/3,对应的励磁线圈电流分别为50 A、100 A、150 A;下长坡时,在巡航档控制模式下,利用PID算法,车辆运行速度恒定。

Electromagnetic liquid cooling retarder has the advantages of high power density,continuous braking with small heat fade.Therefore it is gradually popularized in heavy duty vehicles.Multiple IGBT tubes are parallel each other to drive high power excitation coil,multiple diodes in parallel are used to continue current,uses temperature sensor to detect cooling water temperature,temperature switch is used to detect circuit board temperature,uses high power electromagnetic relay as circuit board thermal protection device,shift handle with 4 gears as signal input element,and the MC9S12XS128MAA singlechip as control system CPU.The test results done on one heavy duty vehicle show that,when the battery terminal voltage is 24.6 V,switching frequency of IGBT tubes is 100 Hz,and the PWM duty cycle value is 1/3,2/3,or 3/3,the high power excitation coil current is 50 A,100 A,or 150 A.Using PID algorithm when the heavy duty vehicle goes down a long slop with cruise control gear,the vehicle can run at constant speed.