Dynamic Performance Improvement of Brushless DC Motors Using a Hybrid MTPV/MTPA Control

Abstract

Brushless dc (BLDC) motors are widely utilized in many applications. The classical maximum torque per ampere (MTPA) and maximum torque per voltage (MTPV) control strategies are commonly used with BLDC motors due to being straightforward and easy to implement. However, these classical control techniques have their own drawbacks. Specifically, the MTPA achieves high efficiency in steady-state but does not fully utilize the torque capability during transients. Meanwhile, the MTPV allows faster dynamic response but degrades the efficiency in steady-state conditions. To fully exploit the advantages of both methods, this paper proposes a new combined control scheme which utilizes MTPA and/or MTPV methods based on the operating conditions. Specifically, during steady-state operation, the MTPA is adopted due to its high efficiency, while the controller smoothly converts to the MTPV in transients to fully exploit the torque capability and achieve faster dynamic response. The proposed hybrid control method is demonstrated on an example industrial BLDC motor and is shown to achieve high efficiency in steady-state (similar to MTPA) and fast dynamic response (similar to MTPV).