Control of a High-speed (<50,000 rpm) Interior Permanent Magnet Synchronous Motor
High-speed interior permanent magnet synchronous motors (HS-IPMSMs) play a critical role in modern industrial and automotive applications, yet their performance is often constrained by losses, parameter variations, and deadtime effects. This thesis investigates advanced field-oriented control (FOC) strategies to address these challenges, with a particular focus on improving efficiency and robustness in HS-IPMSM operation. A comprehensive review of existing control methods highlights the limitations of conventional maximum torque per ampere (MTPA) and loss minimization control (LMC) strategies under parameter variations, particularly in the presence of core loss. To enhance system performance, an improved MTPA strategy that explicitly accounts for core loss is proposed, alongside a novel LMC method that incorporates the partial derivative of core loss resistance with respect to the d-axis current. Analytical and experimental validation on a HS-IPMSM (5kW, 50,000 rpm) demonstrate that these methods effectively reduce electrical losses. Additionally, a hybrid trajectory combining MTPA and LMC is developed to balance efficiency and torque output across varying load conditions. Further investigation into motor parameter variations reveals their substantial impact on both MTPA and LMC performance. A systematic analysis identifies optimal parameter selection strategies, enhancing robustness in real-world applications. To overcome the limitations of polynomial-fitting-based methods, a novel Taylor-series-based approach is proposed for both LMC and MTPA control method (under torque control mode), enabling real-time adaptation to parameter fluctuations through lookup-table-based online estimation. Experimental results confirm its effectiveness in improving efficiency with negligible influence on dynamic performance. The thesis also addresses deadtime-induced distortions, proposing a compensation technique for both static inductance measurement and real-time current control. A standstill flux-linkage-based inductance measurement method with deadtime compensation significantly improves accuracy, with results closely aligning with finite element analysis (FEA) and AC standstill test predictions. Moreover, an enhanced deadtime compensation strategy is introduced to mitigate PWM-induced current ripple, achieving substantial reductions in current ripple magnitude and total harmonic distortion (THD). Collectively, these advancements contribute to the development of more efficient and robust control strategies for HS-IPMSMs, offering improved performance across a wide range of operating conditions. The findings provide valuable insights for the future design and optimization of high-speed motor drive systems, particularly in applications requiring high efficiency with limited computation time.
IPMSM, efficiency,, motor control, high-speed, anzsrc-for: 400806 Electrical machines and drives
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