Regeneration of power in hybrid vehicles

Regeneration is one of the important sources of improving fuel efficiency. When designing the drive train of a hybrid vehicle, special attention must be given to this effect. We analyse the effect of regeneration of the braking energy on the design of the electrical motors and of the battery system. We consider a light urban vehicle and a bus to cover the whole spectrum of possible hybrid vehicles. Induction and permanent magnet synchronous traction motors are designed for both vehicles. We compare and analyse the consequences of their design on the regeneration. The battery behaviour is also considered with the various motors. It is shown that the choice of the motors has little effect on the recuperation and that effective recuperation can be obtained relatively easily if the motors and the braking system are adequately designed and matched. The conclusion is valid practically for all types of hybrid drive trains (series, parallel and series-parallel hybrids).