Control strategy for an electric machine in a vehicle

• Main Author: ISAYEVA RIMMA
• Format: Patent
• Language: English
• Published: 24.02.2015
• Subjects: ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE ORDIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; ELECTRIC EQUIPMENT OR PROPULSION OF ELECTRICALLY-PROPELLEDVEHICLES; ELECTRICITY; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES, IN GENERAL; EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS; GENERATION; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; PERFORMING OPERATIONS; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OFVEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TOTHE CONTROL OF A PARTICULAR SUB-UNIT; TRANSPORTING; VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES; VEHICLES IN GENERAL

A system and method for controlling an electric vehicle include at least one controller configured to detect an over-voltage condition when an electric-machine voltage exceeds an over-voltage threshold. In response to the over-voltage condition, the electric machine and a variable voltage controller (VVC) are disabled. Upon determining the electric-machine voltage is decreased to at least a second threshold being less than the over-voltage threshold, the controller is configured to set the VVC to a limited-operation mode. Upon determining the electric-machine voltage is decreased to at least a third threshold being less than the second threshold and the over-voltage threshold, the controller is configured to re-enable the electric machine and set the VVC to a normal-operation mode. The limited operation-mode enables the vehicle to maintain vehicle propulsion during the drive-cycle as the electric machine is recovered from a transient condition causing the over-voltage condition.