Modeling and Control of a Hybrid Electric Vehicle with an Electrically Assisted Turbocharger

This paper investigates the suitability of using an electrically assisted turbocharger in a hybrid electric vehicle (HEV) with a turbocharged engine, based on fuel economy and acceleration performance. This system has two electric machines, i.e., a traction motor and a boost motor coupled to the shaft of the turbocharger, and offers an additional control variable in the energy management problem i.e., the amount of electrical boost (e-boost) to reduce the turbolag. The task of an optimal controller now becomes manifold: deciding the torque split between the engine and the traction motor, the power of the boost motor, and the gear number. A quasi-static model of a parallel HEV with a turbocharged engine is derived, and a method to model turbolag based on a predefined map for the permissible engine torque is proposed. Dynamic programming (DP) is used to solve the optimal control problem. To find out an optimal tradeoff between the two onboard electric machines, the optimal strategy is calculated with a constraint on the maximum total electrical power. The circumstances in which it is advantageous to use the boost motor are discussed. Furthermore, the influence of powertrain components' size on the control strategy is analyzed, specifically in the problem of maximizing acceleration performance, by scaling the engine displacement volume for different sizes of turbochargers keeping the maximum engine torque and power constant, and scaling the motor map for different nominal power values. The robustness of this modeling approach has also been verified.


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  • Accession Number: 01602906
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jun 21 2016 4:20PM