Field reconstruction and active harmonic elimination techniques implemented in advanced PM motor drive system

This paper presents a methodology based on the Field Reconstruction Method (FRM) and Active Harmonic Elimination (AHE) for advanced low-speed surface-mounted PMSM drive systems. FRM leverages spatial periodicity to enhance Finite Element Analysis (FEA) precision by capturing space harmonics and saturation effects, while the core innovation is the real-time implementation and optimization of AHE. The proposed AHE framework utilizes precomputed lookup tables (LUTs), embedded in the DSP, for harmonic compensation—these LUTs are derived from high-fidelity FEA including nonlinear magnetic behavior and rotor position. Unlike traditional PI-based controllers, this approach introduces a LUT-based harmonic injection map, allowing efficient and precise compensation of dominant current harmonics with minimal computational load, reducing torque ripple and AC losses while staying within PWM constraints. The system dynamically adapts to speed and load changes, providing robust operation under nonlinear magnetization and high-frequency PWM. The methodology was successfully deployed in a prototype EV at the Shell Eco-marathon, where it improved energy efficiency and earned the Innovation Award for its novel integration of a digital twin for predictive harmonic compensation and real-time control. This work demonstrates the capability to conveniently integrate detailed electromagnetic field modeling in digital fast embedded control to develop efficient, compact, and precise low-speed drives.