Differential electrical drive arrangement for heavy duty vehicles

A method for requesting a torque from an electrical machine in a heavy duty vehicle, the electric machine being connected to first and second driven wheels via a differential, and service brakes configured to be used as back-up for handling wheel slip conditions which the electric machine has not been able to control successfully, the method comprising

• configuring a first wheel slip control module associated with the first driven wheel, and a second wheel slip control module associated with the second driven wheel,
• determining, by each wheel slip control module, an obtainable torque for the respective wheel based on a comparison between a current wheel slip and a configurable wheel slip limit,
• receiving a requested acceleration profile by the vehicle,
• determining a required torque to satisfy the requested acceleration profile, and
• requesting a torque from the electrical machine corresponding to the smallest torque out of the obtainable torques for each driven wheel and the required torque,
• wherein the obtainable torque by the respective wheel comprises a peak torque which can be maintained for a first period of time and/or a continuous torque which can be sustained for a second period of time, wherein the second period of time is longer than the first period of time,
• wherein the control unit is arranged to, during propulsion, reduce the requested torque responsive to both service brakes becoming active.