Predictive Trajectory Control with Online MTPA Calculation and Minimization of the Inner Torque Ripple for Permanent-Magnet Synchronous Machines

Abstract

This paper presents an extended predictive trajectory control scheme combined with an inner torque ripple minimization considering the current-, flux-linkage-, and voltage-planes of permanent magnet synchronous machines. The extension of a fundamental machine model with flux-linkage harmonics allows the calculation of the inner torque ripple and enables its minimization. For this, the control is divided in two cases: (1) The dynamic operation or large signal behavior which uses the maximal torque gradient for the trajectory strategy during each control period for fastest dynamic operation, and (2) The stationary operation or small signal behavior, utilizing a real time capable polynomial approximation of the rotor position dependent torque hyperbolas (iso-torque curves) of permanent magnet synchronous machines for the ideal torque to current reference values. Since dynamic and steady-state operation is covered, torque to current look-up tables, such as maximum torque per ampere (MTPA)/maximum torque per volt/voltage (MTPV) look-up tables, are not required anymore. The introduced, new control approach is implemented in Matlab/Simulink based on finite element analysis and measured data. Furthermore, test-bench implementations based on measurement data are presented to show the real-time capability and precision.

Hybrid torque sensing concept for high frequency and dynamic torque ripple measurements for brushless dc motors

“…The calculated torque is based on identified angledependent flux linkages 𝜓 using the method proposed in [3]. Since saturation is not present in most operating points the linear machine parameters in Table II give sufficient insight in the machine characteristics.…”

“…They can lead to additional noise, vibrations and machine resonances [2]. Recently, various control algorithms for torque ripple reduction have been proposed [2,3]. To assess the efficiency of these algorithms, precise torque sensing with a large bandwidth is mandatory.…”

Comparative Analysis of the Steady-State Model Including Non-Linear Flux Linkage Surfaces and the Simplified Linearized Model when Applied to a Highly-Saturated Permanent Magnet Synchronous Machine—Evaluation Based on the Example of the BMW i3 Traction Motor

“…According to the authors' best knowledge, such an attempt has not been documented before. Commonly, during analyses regarding this topic, authors just state that it is important to include saturation effects [23][24][25][26][27][28] in the analysis, without any further discussion. An attempt to analyze this effect more precisely was made in [29].…”

Design of Constraints for Seeking Maximum Torque per Ampere Techniques in an Interior Permanent Magnet Synchronous Motor Control

“…However, motor parameters vary with the change of operating conditions: steel saturation impacts inductances, rotor temperature impacts flux-linkage, etc. Therefore, these variations have to be taken into account [5][6][7].…”