Enhanced Efficiency in Permanent Magnet Synchronous Motor Drive Systems with MEPA Control Based on an Improved Iron Loss Model

This paper investigates the efficiency optimization problem in the drive system of Permanent Magnet Synchronous Motors (PMSM) based on the iron loss resistance model. Initially, an efficiency calculation method is proposed, utilizing the direct current (DC) side power based on the iron loss motor model as the input power. This approach determines the system's input power by measuring DC side voltage and current, accounting for the impacts of temperature, magnetic saturation, and inverter nonlinearity. It avoids the need for intricate nonlinear loss modeling of the inverter, thereby simplifying the computational requirements for system efficiency. Simultaneously, the d-q axis equivalent equations based on the iron loss motor model are employed to calculate the system's output power, enhancing the accuracy of the system efficiency calculation. An improved discrete gradient descent algorithm is presented based on this system efficiency calculation model, accelerating the search for the optimal current angle and improving its accuracy. In comparison to existing methods, this approach exhibits adaptive step size and provides more precise and higher efficiency calculations, resulting in faster search speeds. Experimental and simulation evaluations are conducted to assess the effectiveness of the proposed methods.