Development Of CVT Electric Oil Pump Controller For Hybrid Electric Vehicle

As the energy crisis intensifies,countries around the world have introduced stringent regulations of conserving energy and reducing emissions and vigorously developed new energy vehicles.Driven by this,CVT received a lot of attention,but its transmission efficiency is indeed a major flaw.Research shows that the power loss of CVT oil pump accounts for 42%of the total CVT loss.It is the most important to reduce the oil pump loss for improving the CVT transmission efficiencyThe traditional CVT oil pump is driven directly by the engine crankshaft.Under normal operating conditions,the output flow of the oil pump is much larger than that of the demand,resulting in a large amount of overflow loss,which leads to the decrease of CVT transmission efficiency.To this end,this paper uses a new CVT electric oil pump,adopting the permanent magnet synchronous motor to replace the engine as the power source of the CVT oil pump.In order to follow the CVT oil pump demanding flow,the oil pump motor should realize precise speed control,that is,good dynamic response performance,small steady-state error and speed fluctuation,which require the motor with precise torque control.In view of this problem,the controller uses a vector control algorithm.It can realize accurate torque control by directly controlling the amplitude and phase of stator current vector.Taking into account the defects of the motor body and the non-linearity of the inverter in the design of the CVT electric oil pump system,the harmonic processing algorithm is added to the controller,which injecting harmonic voltage to suppress the torque ripple.In order to verify the effectiveness of the control algorithm,this paper builds a simulation model of the oil pump motor control system on the Simulink platform.The simulation is carried out for the ideal and non-ideal conditions respectively,and the feasibility of the vector control and the method harmonic voltage injection is verified.On the basis of the simulation results,this paper determines the overall scheme of the CVT electric oil pump controller,designs the corresponding hardware and software,discusses the composition and principle of each function module,and carries on the preliminary experimental verification.