Optimization of the Power Drive of a Mild Hybrid Vehicle

Abstract

The prospects of hybrid cars in modern conditions are shown. However, hybrid cars are more complex and more expensive than conventional cars. To provide a competitive price for hybrid vehicles, Mild Hybrid Electric Vehicles (MHEVs) have been developed that use smaller electric motors and smaller capacity batteries. To improve the economic and environmental parameters of a mild hybrid vehicle, a new algorithm for the operation of a traction electric motor is proposed and substantiated, which makes the regenerative braking of a mild hybrid vehicle more efficient. In the proposed vehicle in hybrid mode, in order to minimize the power of the traction electric drive, the operation mode of the internal combustion engine with a low load, but with a high specific fuel consumption, is replaced by electric drive. This is a uniform movement with a relatively low speed (40–60 km/h) and low accelerations on an asphalt road without a noticeable rise. The idle mode of the internal combustion engine is also excluded. The performed calculations and experimental studies show that the uniform movement of such a hybrid car with a low-power electric motor in the electric drive mode is possible in urban conditions, for which a special algorithm has been developed. It is shown that the most suitable for such a car is an asynchronous electric motor. A technique for optimizing the control of a traction asynchronous motor based on the frequency scalar method, taking into account the load of the electric motor, is proposed and justified. The expediency and efficiency of the proposed methods of driving a car and a traction asynchronous electric motor are shown.