Abstract
The electric power demand in vehicles is rising steadily due to new electric systems that enhance passenger comfort and safety. Electric compressors for A/C (air-conditioning system) have advantages of an efficient variable speed operation for "stop and go" vehicles to improved fuel economy. But, electric compressors consume much electric power of 1- 4 kW. It is necessary to control the power flow which has be done by an energy management system.There exits an enormous number of proposals for the energy management strategy for mild hybrid vehicles. All the mentioned approaches look the optimal choice of the control variables (engine power, motor power) to minimize fuel consumption during pre-determined vehicle operation or predetermined driving route, without electric power demand for HVAC systems.This paper demonstrates a systematic energy management design with the electric power demand for A/C systems. The energy management has then to solve an optimization procedure, which has the goal to find the maximum objective function which is the weighted sum of fuel economy and comfort. The power demand of the electric compressor is estimated using a dynamic model of automotive conditioning systems. The
power demand of the vehicle driving is estimated using a stochastic modeling (Markov model). The dynamic optimization is applied for the sum of the power demand for the electric compressor and the vehicle driving.The simulations were performed and shows the proposed approach provides a directly implementable control design path for mild hybrid vehicles with A/C electric driven compressor.
Keywords - Hybrid vehicle, Energy management, Air conditioning system, Compressor, Electric drive