Electronic control apparatus and its fault detection method

A fault detection method by an electronic control apparatus including:

• a plurality of electrical systems, each of which is connected to a different external power supply;
• an inverter that is included in each of the electrical systems and that drives, among a plurality of separate winding sets of a motor, a predetermined winding set in the corresponding electrical system;
• a control circuit that is included in each of the electrical systems and that controls the inverter in the corresponding electrical system;
• a control system common ground to which the control circuits in the electrical systems are commonly connected;
• a connector that is included in each of the electrical systems and that connects a control system negative line from the control system common ground and a drive system negative line from a negative bus of the corresponding inverter with a negative power supply line from the corresponding external power supply;
• a connection line that mutually connects the drive system negative lines between the electrical systems;
• and a current state detection circuit that is installed on the connection line and that detects current states of the connection line,
• the fault detection method comprising:
• causing the control circuit in each electrical system to detect, based on the current state, whether an open fault has occurred in the corresponding connector or negative power supply line in the corresponding electrical system;
• causing the control circuit to limit control on the corresponding inverter in the corresponding electrical system when the control circuit detects occurrence of the open fault;
• and
• causing the control circuit to continue control on the corresponding inverter in the corresponding electrical system when the control circuit does not detect occurrence of the open fault.