Study Of Efect On Engine Performance Of Electric Supercharger Based On Simulation

The turbocharging technique has become the most common way to reduce the discharge of CO₂ because it makes engine smaller.However,because of the inherent“turbo lag”of turbocharger,the charge pressure is not enough during the start-up or accelerating and hence,the dynamic performance is badly affected.Moreover,the emission is as well affected due to the influence on catalysts’pre-heat of turbo.Compared to turbocharger,the electric supercharger can improve the dynamic performance of engine and emission because the drive energy is absolutely from the electric energy which is independent from exhaust’s power.There are many kinds of motors,but only two types of motors when they are classified by motor’s position and function,i.e.electric turbocharger and electrically driven compressor.By comparison,the latter one is more suitable and therefore it is the main study subject of this topic.The most important component of the supercharger is its driven motor,the high-speed makes normal motor impossibly drive the compressor of the electric supercharger.So far,the available motors are switched reluctance motor and the permanent magnet synchronous motor,and the more suitable one can be selected dependent on demand by comparison of the working principle and control method.The control strategy of the electric supercharger is closed-loop,which includes feed-forward and feedback.The feed-forward control is based on the compressor performance MAP according to the actual reduce mass flow and desired pressure ratio,then outputs the compressor’s speed and the state of bypass and is limited by SOC and system heat.The feedback control includes PI control,fuzzy control and its combination i.e.F-PI control.Deviation between the desired charge pressure and the actual charge pressure is to control the speed of electric supercharger and is bypass’s state.Then the control methods are tested based on the coupled simulation of GT-POWER and MATLAB/Simulink,and control methods are compared about the steady error and dynamic respond and choose the better one.The analysis method of steady error is to sum up the error of every sequence,the steady performance is better if it sum is smaller.Likewise,the time when the actual charge pressure reaches the desired pressure is shorter,the dynamic performance is better.At last,both the steady and dynamic performance of engine affected by supercharger is studied based on the proven method,which offers a reference for the future test bench and vehicle application.