User-oriented control of a drive system over the whole operating range

Defining an operating point of an existing drive system depends on the exact knowledge and modeling of the system and its corresponding degrees of freedom. To optimize the operating point, the individual adjustment to the needs of the user has to be part of the design process as well. The proposed approach is based on a stationary loss model consisting of equivalent circuits and characteristic diagrams of the drive system components parametrized with measurement data. Fixed input values are the desired torque and speed. A better comprehension of the system leads to a simple analytical model in the rotor-oriented dq-reference frame considering saturation effects and losses. Furthermore, the obtained current operating points depending on the user profile serve as input values for the existing current controller. The examined system contains an electronically commutated permanent magnet synchronous machine, a gearbox and a lithium-ion battery. Simulations and analyses on the test bench indicate that the deduced model representation and the adaption of the operating points as basis for the control algorithm are very effective. The results show a reduced model error of torque magnitude by up to 3% and an efficiency enhancement of up to 2%.