SummaryIn this paper, saturation and temperature variation effects on control of permanent magnet synchronous motors are investigated in terms of motor loss on different control methods including "unity power factor," "maximum torque per ampere," and "loss minimization." Afterwards, a hybrid compensation method is proposed to improve the response time to reach maximum efficiency point. In the proposed method, to improve the response time to reach maximum efficiency point, initial value of optimum operating point is determined via model-based method. Then, based on perturb and observe method, d-axis reference current is changed step by step. Next value of d-axis reference current is determined via measuring direction of dc-link power variation. Also, the proposed hybrid method is compared with a conventional search-based method under different parameter variation and step load and reference speed implementation. The proposed hybrid compensation algorithm has been experimentally implemented and proved to be a practically useful method to improve the response time to reach maximum efficiency point under parameter variation and also under load and speed variation. | INTRODUCTIONAccording to energy prices and energy efficiency policies, energy saving has a great importance. However, electrical motors have great deal of power consumption; therefore, reducing loss of electrical motors by just a few percent has a great impact on total power consumption. Although permanent magnet synchronous motors (PMSMs) are widely used in industry due to high efficiency, high energy density, low torque ripple, fast dynamic response, etc. [1][2][3][4][5][6] Controlling the PMSMs can be performed via different control methods. Some of these methods such as i d = 0 or search-based loss minimization control methods are independent of motor parameters. [7][8][9] In contrast, in some methods,