An electric propulsion system 3 for a vehicle 1 includes a first electric motor 9, a second electric motor 11 and a controller 27. In at least one vehicle operation mode, the controller controls the proportion of power delivered from each of the first and second electric motors for propulsion of the vehicle. When a total demanded propulsion power is a first power at a first vehicle speed, more propulsion power is delivered from the first electric motor than the second electric motor. When a total demanded propulsion power is a second power at a second vehicle speed, more propulsion power is delivered from the second electric motor than the first electric motor. The proportion of power delivered from each of the first and second electric motors may be controlled in dependence on: the total demanded propulsion power, the vehicle speed and the respective efficiency characteristics of power delivered from the first and second motors; or the speed of the vehicle and a peak in a plot of system efficiency against proportion of torque delivered by each of the first and second electric motors. The first electric motor may be a permanent magnet, wound field synchronous, induction motor or switched reluctance configuration. The second electric motor may be a different one of these configurations.
Vehicle propulsion system
2020-09-30
Patent
Electronic Resource
English