Control Strategy For An Electric Machine In A Vehicle

A vehicle comprising:

• a fraction battery;
• an electric machine;
• a variable voltage converter (VVC);
• and
• at least one controller configured to:
• detect when a voltage of one of the electric machine and the VVC exceeds an over-voltage threshold;
• disable the electric machine and the VVC in response to the voltage exceeding the over-voltage threshold;
• operate the VVC in a limited-operation mode in response to determining the voltage decreased to at least a second threshold being less than the over-voltage threshold;
• in response to determining the voltage decreased to at least a third threshold being less than the second threshold and the over-voltage threshold:
• re-enabling the electric machine;
• and
• operating the VVC in a normal-operation mode,
• wherein the limited-operation mode enables the vehicle to maintain vehicle propulsion during a drive-cycle.

A method of controlling a hybrid-electric vehicle comprising:

• detecting an over-voltage condition when an electric-machine voltage exceeds an over-voltage threshold;
• disabling the electric machine in response to the over-voltage condition;
• upon determining the electric-machine voltage decreased to at least a second threshold being less than the over-voltage threshold, setting a variable voltage converter (VVC) to a limited-operation mode;
• upon determining the electric-machine voltage decreased to at least a third threshold being less than the second threshold and over-voltage threshold:
• re-enabling the electric machine;
• and
• setting the VVC to a normal-operation mode,
• wherein the limited-operation mode enables the vehicle to maintain vehicle propulsion during a drive-cycle.