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The conventional direct torque control (DTC) has high torque and stator flux fluctuation that causes the stator current distortion. This paper presents an efficient control method based on the feedback-linearization direct torque control (FL-DTC) method for an interior permanent magnet synchronous motor (IPMSM) drive by using an improved firefly algorithm. The proposed approach can greatly restrain the poor performance of torque and stator flux. Thus, it is suitable for IPMSM drives in electric vehicles. First, a decoupled linear model is derived to implement the proposed efficient feedback linearization control for the IPMSM. Two phase voltages in d-q axes and two additional control inputs take shape into an isomorphism mapping with the concept of orthogonal transformation. The torque generation is related to the additional control. Second, the Hamiltonian efficient control theory combined with an improved firefly algorithm is applied to obtain an analytical solution. An efficient linearization controller is designed with a cost function considering the maximum voltage of the inverter. Finally, simulation and experiment are carried out to compare the performance of the proposed efficient FL-DTC with the improved firefly algorithm and the conventional direct torque control. The results show that the proposed control method can reduce the torque and flux ripples at a steady state and maintains a good dynamic response with the variations of speed and torque. • To restrain the poor performance of torque and stator flux, this paper presents an optimal control method based on feedback-linearization direct torque control (FL-DTC) method for an interior permanent magnet synchronous motor (IPMSM) drive by using an advanced firefly algorithm. • A decoupled linear model is derived to implement the proposed optimal feedback linearization control for the IPMSM. Two phase voltages in d-q axes and two additional control inputs take shape into an isomorphism mapping with the concept of orthogonal transformation. • The Hamiltonian of optimal control theory based on an advanced firefly algorithm is applied to obtain an analytical solution. • An optimal linearization controller is designed with a cost function considering the maximum voltage of the inverter. • The proposed control method has faster torque response and smaller torque and stator flux fluctuation. [ABSTRACT FROM AUTHOR]

In view of the lack of the role of reluctance torque in the electromagnetic torque output of the motor under the previous control logic with id=0, only the excitation torque component is working. Therefore, on the premise of inputting unit current, the output electromagnetic torque cannot reach the maximum value, resulting in low energy utilization, reduced load capacity and low operation efficiency. The maximum torque control of unit current output is proposed to control id to pursue the maximum torque. This control method studies the mathematical model of the Interior Permanent Magnet Synchronous Motor (IPMSM) in the rotating d-q-O coordinate system, and establishes the relationship between the current and torque of IPMSM through mathematical formula derivation, so as to realize the Maximum Torque Per Ampere (MTPA) control of the IPMSM. Through Simulink simulation, compared with the previous control logic with id=0, when MTPA control logic outputs the same electromagnetic torque value, the stator current value of IPMSM is smaller and the energy utilization rate is the highest, thus improving the operation efficiency. [ABSTRACT FROM AUTHOR]

In this paper, a novel initial rotor position estimation method for reliable start-up of the IPMSM is presented. The proposed method combines the improved high frequency pulse signal injection with positive and negative d -axis current bias injection. Differing from the conventional initial rotor position detection scheme, the injection and the field-oriented control periods are separated in the proposed method. Therefore, the filters are not needed in the process of high-frequency response current and fundamental current extraction. The magnet polarity can be estimated by exciting the positive and negative d -axis currents. Afterwards, the peak values of d -axis current during the voltage injection period are accumulated to detect the rotor magnetic polarity. The proposed method can improve the reliability of the magnet polarity detection. Moreover, it is suitable for both the standstill rotor application and the free-running rotor application. The effectiveness of the proposed method is verified on a 1.5 kW IPMSM drive platform. • A reliable initial rotor position detection method for sensorless control of the IPMSM is presented. • No filters are needed for extracting the fundamental currents and the induced currents. • The proposed method can improve the reliability of magnet polarity detection. • The proposed method is suitable for standstill rotor application and free-running rotor application. [ABSTRACT FROM AUTHOR]

• We propose a method for detecting the misalignment of shaft connected to the motor. • This method enables efficient system management by condition-based maintenance. • Current data on frequency domain are useful for detecting the misalignment of shaft. • The method can detect the misalignment as well as its severity. • The method was proposed based on simulation results and it was experimentally verified. With the increasing demand for automated manufacturing and logistics system, interior permanent magnet synchronous motors (IPMSMs) are being actively researched because of their high torque density and efficiency. Consequently, fault diagnosis technology for electric motors is important for detecting abnormal signs of motors and evaluating the fault type and its severity. It enables condition-based maintenance of the main drive power of smart manufacturing as well as logistics system. Among the different types of faults in an IPMSM, shaft misalignment can cause various problems, including noise, vibration, and torque ripple, and shorten the life of the motor and gear connected to the shaft of the motor. This study investigates the fault characteristics of parallel misalignment, focusing on the characteristics of the frequency domain and size of the load fluctuation. The modeling and simulation for a drive system consisting of an IPMSM controlled by an inverter were carried out. Experiments were conducted to verify the simulation results and validate the effectiveness of the proposed method. The results show that motor current signal analysis can be used to detect misalignment faults under various conditions. We found that shaft misalignment generates abnormal current signals, which are correlated with fault severity, in the frequency domain. [ABSTRACT FROM AUTHOR]

In this paper a robust sensorless control for an Interior Permanent Magnet Synchronous Motor (IPMSM) is designed. The proposed control strategy uses a backstepping controller, whose robustness is improved by using integral actions added at each step of the original algorithm, and by a Maximum-Torque-Per-Ampere strategy (MTPA) to improve its energy efficient operation. Furthermore, to implement this controller in the framework of the mechanical sensorless control from the only measurements of the currents and voltages, an adaptive interconnected high gain observer is developed for estimating the rotor speed, the position and the load torque. Moreover, sufficient conditions are given to ensure the practical stability of the Observer-Controller system even if bounded uncertainties occur. Finally, the performance and the effectiveness of the designed method are tested experimentally throw a significant benchmark including different speed references and with significant robustness tests. A comparative evaluation of the computational effort of our scheme with respect to classical motor control is given. [ABSTRACT FROM AUTHOR]