DETECTION OF WELDED CONTACTOR USING AC COUPLING

A system for detecting a condition of a contactor configured to connect a battery string to a direct-current bus in a vehicle may include a controller configured to open or close the contactor. The system may also include an alternating-current (AC) signal source configured to provide an AC test signal when the controller opens the contactor. The system may further include an AC coupling circuit. The AC coupling circuit may include a primary side of the AC coupling circuit connected to the AC test signal source, and a secondary side connected to the contactor. The system may also include a detection circuit configured to receive an AC return signal corresponding to the AC test signal, and determine a defective condition of the contactor based on the AC return signal. 种用于检测被配置为将电池串连接到车辆中的直流总线的接触器的状况的系统可以包括被配置为断开或接通接触器的控制器。该系统还可以包括被配置为当控制器断开接触器时提供AC测试信号的交流(AC)信号源。该系统还可以包括AC耦合电路。AC耦合电路可以包括连接到AC测试信号源的AC耦合电路的初级侧，以及连接到接触器的次级侧。该系统还可以包括被配置为接收对应于AC测试信号的AC返回信号，并且基于AC返回信号确定接触器的缺陷状况的检测电路。