Method and system for controlling an isolated HV circuit

摘要

An isolated high voltage circuit 12 of a vehicle 10 is isolated from a low voltage circuit 28 is controlled by detecting a change in isolation resistance of the high voltage circuit 12 from the low voltage circuit 28, determining an indication from the driver of intended speed of the vehicle 10 and operating the high voltage circuit 12 or a human machine interface in dependence on the change in the isolation resistance and the user-input indicated desired speed of the vehicle 10. The actual velocity of the vehicle may be sensed rather than the intended velocity commanded by the driver. The control method may be implemented depending on whether the isolation between high and low voltage circuits was functioning when last the vehicle was used. The high voltage circuit 12 may be disconnected, or may be reconnected having already been disconnected before measuring the speed. The control dependence on the speed may be according to a measured speed threshold, which may vary according to the status of the vehicle 10, for example depending on if the vehicle 10 is in water.