Consideration of Belt Losses of a Belt-Starter Generator(BSG)/Front-End Accessory Drive Electric Machine in an Optimal Torque Control Problem of a Hybrid Supervisory Controller 2024-01-2157

As electrification of powertrains is progressing, diversification of hybrid powertrains increases. This generally imposes the challenge for a supervisory controller of how to optimally control the torque of the electric machine(s). Architectures, which have at least one belt driven electric machine, are an essential part of the portfolio. This paper describes a strategy on how to include the losses of the belt device in the determination of optimal electric machine torque command.

It first depicts a physics-based method for controlling optimal electric machine torque command for systems without a belt connected electric machine. This method considers the constraints of the electric machine(s) as well as the power limitations from the electric devices, which supply power to the motors. The solution presented in this paper, utilizes a control method, which uses a quadratic fit of electric machine losses and a mathematical formulation for an analytic solution of the problem, which is then enhanced to consider the losses of the belt connection as well. The software concept of the supervisory control utilizes remapping and reformulation of the interfaced communication signals to the motor control unit, which are executed in real-time on the supervisory control. The benefits of this method are increased efficiency, a more robust consideration of constraints and significant computational efficiency gained by avoiding additional optimization loops.