Real-time HiL Model of Variable Flux Synchronous Motor Drives

Variable Flux Machines (VFMs) employ low coercivity permanent magnets that allow intentional demagnetization and remagnetization to optimize drive performance. Accurate modeling of their nonlinear magnetic behavior, including irreversible demagnetization and load dependent asymmetric flux linkage, typically relies on computationally intensive Finite Element Analysis (FEA), which is unsuitable for advanced control development and real-time applications. This paper proposes a simplified VFM model that captures the essential magnetic phenomena without requiring FEA. The model significantly reduces computational effort while maintaining high accuracy. Its efficiency enables real-time Hardware in the Loop (HiL) implementation on a PLEXIM RT Box 2 with control executed on an STM32G4 microcontroller. Validation against FEA demonstrates strong agreement and substantial computation time reduction, making the proposed approach suitable for real-time validation and control development of VFMs.