A power converter assembly comprises a plurality of power converter channels each arranged to provide a three-phase output to an electrical machine having a multiple of three-phase windings. The power converter assembly further comprises control means arranged to provide a torque demand signal to the plurality of power converter channels to provide, together, a desired torque output to drive the machine and a temperature sensing means to detect temperature in the power channels and/or at the windings of the machine. The control means is arranged to determine the proportion of the desired torque output to be provided by each channel based on the detected temperature.