整车电气系统—ISO7637-2 Part 3

那我们接着来完成关于EMC测试过程中抛负载测试，我们接着往下看后边的设计内容，基于上一篇文章的内容主要是就剩下5a、5b，接下来我们开始往下继续完成所有的ISO7637-2的脉冲信息。备注：The test pulses 4、5a and 5b have been removed from the ISO7637, since  the specified in ISO16750-2 and ISO21848.试验脉冲5a和5b：模拟抛负载瞬态现象,这种模拟是当交流发电机给给车内的铅蓄电池和其他的电子负载供电，在断开电池（亏电状态或者电池的螺丝没有锁紧的状况）的同时，此时发电机的功率并没有降低，但是车内的主电路的需求功率却瞬间降低，交流发电机正在产生充电电流，而发电机电路上仍有其它负载时产生的瞬态，未断开时发电机的线圈内的的电流较大，断开时候突然电流变小，产生反动势；抛负载的幅度取决于断开电池连接时，发电机的转速和发电机的励磁场强的大小。抛负载脉冲宽度主要取决于励磁电路的时间常数和脉冲幅度。大多数新型交流发电机内部，抛负载幅度由于增加限幅二极管而受到抑制（箝位）。P5脉冲的幅度较高（100~200V,相对于系统电源电压来说，这已经算是高电压了）、宽度较大(达几百毫秒)、内阻有极低（几欧姆，甚至零点几欧姆），所以在ISO7637-2标准里，P5脉冲属于能量比较大的脉冲。除了考核被试设备在P5作用下的抗干扰能力外，在当前程度上还在考核它对设备元器件的破坏性。

Class A through Class E operation is defined  as follows:Class AAll functions of the device/system perform as designed during and after the test.Class BAll functions of the device/system perform as designed during the test. However, one or more may go beyond the specified tolerance. All functions return automatically to within normal limits after the test. Memory functions shall remain Class A.Class COne or more functions of a device/system do not perform as designed during the test but return automatically to normal operation after the test.Class DOne or more functions of a device/system do not perform as designed during the test and do not return to normal operation after the test until the device/system is reset by simple “operator/use” action.Class EOne or more functions of a device/system do not perform as designed during and after the test and cannot be returned to proper operation without repairing or replacing the device/system

引用 Refreences

本文由不架构的汽车电子电气本文由不架构的汽车电子电气原创，作者：Feynman-Yang。