Control system and method for controlling an electric motor

A method of controlling an electric motor of a vehicle, the electric motor for providing a regenerative braking torque, the method comprising:

• receiving one or more electrical signals indicative of a surface indicator providing information relating to surface drag;
• determining a target deceleration based on the surface indicator such that in the case of relatively high drag surface the target vehicle deceleration is reduced compared with the case of relatively low surface drag;
• receiving one or more electrical signal indicative of a deceleration demand;
• determining, based on said one or more electrical signals indicative of a deceleration demand, a requirement to decelerate the vehicle;
• and
• outputting a torque control signal to the electric motor in dependence on determining the requirement to decelerate the vehicle, wherein the torque control signal is configured to cause the electric motor to generate the target deceleration.

A controller for controlling an electric motor of a vehicle, the electric motor for providing a regenerative braking torque, the controller including:

• means for receiving one or more electrical signals indicative of a surface indicator providing information relating to surface drag;
• means for receiving one or more electrical signals indicative of a deceleration demand;
• means for determining a target vehicle deceleration in dependence on the surface indicator such that in the case of relatively high drag surface the target vehicle deceleration is reduced compared with the case of relatively low surface drag;
• means for determining, based on said one or more electrical signals indicative of a deceleration demand, a requirement to decelerate the vehicle;
• and
• means for, in dependence on determining said requirement, outputting the control signal to the electric motor.