Electric motor torque control for electric vehicles

A method of controlling torque of an electric motor of an electric vehicle, the method comprising:

• defining multiple motor speed breakpoints associated with an acceleration path of an electric vehicle;
• obtaining, at each of multiple motor speed breakpoints, an efficiency value for each of multiple torque settings of an electric motor;
• at each torque setting for each motor speed breakpoint:
• computing an amount of power used from a battery system of the electric vehicle to maintain the torque setting until a next one of the multiple motor speed breakpoints is reached;
• determining a time period to accelerate from the motor speed breakpoint to a next one of the multiple motor speed breakpoints;
• and
• calculating an amount of energy consumed to accelerate from the motor speed breakpoint to a next one of the multiple motor speed breakpoints according to the amount of power and the time period;
• for each of the multiple motor speed breakpoints:
• identifying one of the multiple torque settings corresponding to the motor speed breakpoint, having a lowest amount of energy consumed;
• and
• storing the identified one of the multiple torque settings in a low energy torque curve profile;
• controlling operation of the electric motor according to the low energy torque curve profile;
• determining a maximum torque constraint indicative of a maximum torque at which the electric motor is able to ramp down to a torque setting associated with a target speed within a target acceleration time period between the motor speed breakpoint associated with at least one of the multiple torque settings and the target speed, wherein the maximum torque constraint is determined based on a maximum ramp rate of the motor to inhibit overshoot of the target ending speed;
• and
• in response to determining that the at least one of the multiple torque settings exceeds the maximum torque constraint, adjusting the at least one of the multiple torque settings to a value of the maximum torque constraint.

An electric vehicle acceleration control system comprising:

• an electric motor configured to drive wheels of an electric vehicle;
• a steering wheel configured to steer the wheels of the electric vehicle;
• an acceleration paddle adjacent the steering wheel;
• and
• a vehicle control module configured to, in response to detecting activation of the acceleration paddle:
• obtain a stored low energy torque profile from a memory associated with the vehicle control module, the stored low energy torque profile including, for each of multiple motor speed breakpoints, a specified torque value having a lowest amount of energy consumed within a group of torque values associated with the multiple motor speed breakpoint;
• determine a current speed of the electric vehicle and a target speed of the electric vehicle;
• control the electric motor by commanding the specified torque value of the stored low energy torque profile associated with the motor speed breakpoint that corresponds to the current speed of the electric vehicle;
• determine a maximum torque constraint indicative of a maximum torque at which the electric motor is able to ramp down to a torque setting associated with the target speed value within a target acceleration time period between a current one of the multiple motor speed breakpoints and the target speed, wherein the maximum torque constraint is determined based on a maximum ramp rate of the motor to inhibit overshoot of the target ending speed;
• and
• in response to determining that a torque setting associated with the current one of the motor speed breakpoints exceeds the maximum torque constraint, adjusting the torque setting associated with current one of the multiple motor speed breakpoints to a value of the maximum torque constraint.