聊聊高压互锁 (HVIL)
http://mmbiz.qpic.cn/mmbiz/icDRsboO3nzLjyc7n4onVuSJqh5lEkXGaUXYDjH9tVpTfb5rYnDR5RaEpPaWFsTMJJMP0OWIBjBn7sO5sUzyOow/0高压互锁的目的是,用来确认整个高压系统的完整性的,当高压系统回路断开或者完整性受到破坏的时候,就需要启动安全措施了。
这里面有几个关键:
[*]HVIL的存在,可以使得在高压总线上电之前,就知道整个系统的完整性,也就是说在电池系统主、负继电器闭合给电之前就防患于未然
[*]HVIL的存在,是需要整个系统构成的,如下图所示
[*]HVIL主要通过连接器上完成的,主要防范的对象是线束&连接器的连接来确定,
[*]这里不能覆盖各个部件外壳被打开的情况,所以每个高压部件开盖检测电路是独立存在的
[*]HVIL是存在源电路,在各个其他部分是一个旁路的连接
[*]充电回路和放电回路的HVIL可能是分开的,看具体设计者来确定
http://mmbiz.qpic.cn/mmbiz/icDRsboO3nzIzlGqTKsn3UMTdApRtc4MK5sj1E297uMUeBcavIpkC7sNxXM7zgKMoqYc81dRQ2CQ06EHrtUnYgw/0
HVIL连接器
总体策略(参考文件1的简介):
A High Voltage Interlock Loop (HVIL) system and Control Strategy is provided for an alternative fuel vehicle including an electric, a hybrid electric, or a fuel cell vehicle. Generally, the HVIL system having associated logic including an HVIL circuit is provided to allow the vehicle to operate in either a high voltage (HV) or power mode powered by a power source or a HVIL interrupt mode based on an operational state of the HVIL system. When HVIL circuit fails shorted high, low or open, a Diagnostic Trouble Code (DTC) is set and the Service Soon Lamp is illuminated to indicate to a service technician that additional safety precautions need to be taken when servicing the HV system. The HV contactors may or may not be activated providing HV to the vehicle when HV is not expected to be present at connectors and HV devices.
注意:
[*]HVIL电路需要做诊断(短路、断路和开路)=>仪表盘上的维修显示
[*]这个电路在车子没动之前要做的事情很多,更多的是一种预警
[*]车子动了,万一哪处断开了,就需要组合的安全策略来防护了
[*]逆变器的连接器的供电设计,还是需要费更多的心思的
[*]小电流的功能性连接设计,如DC-DC之类,安全等级还是要低一些
最后谈谈源电路
1)方案1 用12V信号传输
最早最早是这样设计的,这时候诊断要求不高。
http://mmbiz.qpic.cn/mmbiz/icDRsboO3nzIzlGqTKsn3UMTdApRtc4MKdicFNkENkZczSJ620HHxTwib7edHAjc3jibtZ9QmdJFNKoAvpicpsjBQlQ/0
后来就演变成这样的了:
http://mmbiz.qpic.cn/mmbiz/icDRsboO3nzIzlGqTKsn3UMTdApRtc4MKPmpFTCTeonqNYosKiaWgqpQiayr2cPmicTN0m0csSoMQNg0uSqvDaXN2g/0
2)方案2 用5V信号传输
用5V传送信号,区别是需要一个单独的LDO或者参考源传输,方便了逻辑检查,诊断方面也简单些;。
3)PWM信号传输
检测更快些,刚开始看到这种电路设计略有些奇怪。相比较用电平来探测,PWM检测要略微快一些,软件上也简单些,特别是可以设置睡眠唤醒机制上进行调整,节约点功耗。以下选自参考文件3,德国人的设计
When used as a monitoring device, the BCU monitors opening of the battery pack. This is achieved by virtue of an already present hardWare sWitching inhibitor of the battery management system (BMS) being used. By Way of example,a high voltage monitoring loop (HVIL) can be used as such a hardWare sWitching inhibitor. A hardWare sWitching inhibitor alloWs the ascertainment of unconnected standalone contacts in order to prevent people from coming into contact With lines carrying high voltage. This hardWare sWitching inhibitor comprises a PWM (pulse Width modulation) signal generator of the BMS, Which PWM signal generator applies its signals to a series of loop contacts. When the high voltage connection is not connected, the chain is interrupted. An interrupted chain of this kind is recognized by the hardWare sWitching inhibitor of the BMS, Which in this case no longer receives a PWM signal.
这将通过利用蓄电池管理系统(BMS)的已经现有的硬件闭锁来实现。能够例如将高压监控电路(HVIL)用作这样的硬件闭锁。硬件闭锁能够实现未连接的、单独存在的触点的确定,以便阻止人员与传导高电压的导线的接触。 硬件闭锁包括BMS的PWM信号发生器 , 信号发生器将其信号施加在多个循环触点上。当高电压连接端未连接时,将中断该链。将通过BSM的硬件闭锁来识别这样中断的链,在这种情况下该BMS不再会接收到PWM信号。在这种情况下,BMS立刻分离所有的触点。此外,所有其他的激活的、能够将高电压给出至总线的部件同样阻止将高电压给出至该总线。 硬件闭锁能够确保在BCU未被告知蓄电池组的打开的情况下不能打开该蓄电池组。
源电路的布置:一般这里的电路,有两个位置可以放
[*]电池管理单元BMS上:好处就是能量的释放段的源头也在那里,不过缺点是做完了监测还得发给整车控制器
[*]整车控制器:车上,它得到的信息最多,从安全决策上,它说了算,所以放在这里
参考文献:
[*]US 7586722 High voltage interlock system and control strategy
[*]高压互锁 安菲诺
[*]US 20140035592 A1 Method for monitoring a battery pack, battery with a monitoring module and a motor vehicle with a corresponding battery
(转自微信公众号“汽车电子设计”, 2014.8.25)
页:
[1]