System and method for controlling motors of commercial vehicle having electric axle

A motor control method for a commercial vehicle having an electric axle, the method comprising:

• detecting, by an accelerator position sensor, a degree to which an accelerator is depressed;
• detecting, by a wheel speed sensor, a wheel speed change;
• determining, by a controller, a driver's required torque based on detection signals of the accelerator position sensor and the wheel speed sensor, respectively;
• and
• upon determining the driver's required torque, controlling, by the controller, a first motor torque of a first motor disposed in a rear-wheel electric axle to approach a target torque for satisfying the driver's required torque, according to a magnitude of the determined driver's required torque while either controlling a second motor torque of a second motor disposed in the rear-wheel electric axle to a level that compensates for a torque error of the first motor or controlling the first motor torque and the second motor torque at alternating fixed duty ratios,
• wherein, when the first motor torque and the second motor torque are controlled at the alternating fixed duty ratios, a maximum-torque period for the first motor and a maximum-torque period for the second motor are determined as being shorter than a time taken for a temperature of each motor to reach a maximum reference temperature.

A motor control system for a commercial vehicle having an electric axle, the motor control system comprising:

• a first motor and a second motor disposed in a rear-wheel electric axle;
• an accelerator position sensor configured to detect a degree to which an accelerator is depressed;
• a wheel speed sensor configured to detect a wheel speed change;
• and
• a controller configured to:
• determine a driver's required torque based on detection signals of the accelerator position sensor and the wheel speed sensor, respectively, and
• control a first motor torque of the first motor to approach a target torque for satisfying the driver's required torque while either controlling a second motor torque of the second motor to a level that compensates for a torque error of the first motor when an actual output torque of the first motor includes the torque error that is a distance away from the target torque for satisfying the driver's required torque, or controlling a maxim-torque period for the first motor and a maximum-torque period for the second motor at alternating fixed duty ratios.