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    High sensitive torque control of permanent magnet synchronous motor for national military applications
    (Graduate School, 2021-07-26) Köse, Mehmet Eralp ; Kocabaş, Derya Ahmet ; 504181249 ; Electronics and Communication Engineering ; Elektronik ve Haberleşme Mühendisliği
    Electric motors are systems that convert electrical energy into mechanical energy, and they have a very important place in the industry. DC motors are often preferred for applications that do not require driving precision due to their ease of use and low cost. On the other hand, alternating current motors have many superior features over direct current motors. Alternating current motors have higher efficiency, lower maintenance costs, and high torque to volume ratio. They are more reliable and durable motors. One of the most important advantages of alternating current motors is that they offer superior motor control opportunities. With these motors, speed and torque control can be done with appropriate control methods. With the appropriate control method, torque control can be done at very low speeds. Because of these features, alternating current motors are preferred in control applications that require precision. With the developing magnet technology, permanent magnet electric motors come to the fore with their high efficiency. Power electronics and control applications are used together for the control of alternating current motors, and there are different methods and circuit structures in the literature for this. Control methods are basically divided into two as scalar and vector control. In scalar control, the "voltage/frequency" ratio is kept constant so that the flux remains constant, and the speed and torque are adjusted with the change in frequency. In this method, only the magnitudes of flux and current are controlled, rotor position information is not received as feedback and is not included in the control loop. In vector control, in addition to the magnitude of the flux and the current, the angle between them is also controlled, and rotor position information is required as feedback while speed and torque controls are being made. Direct torque control and field-oriented control are sub-branches of vector control. In field-oriented control, which is the focus of this study, the rotor position is needed. This information can be obtained with sensors, or it can be detected by sensorless estimation methods, and position information is used in control. In this way, while precise speed and torque controls are carried out, a more stable control is provided in a steady-state condition. In this thesis, high precision torque control of permanent magnet synchronous motors for use in military systems has been studied. The main goal is to design motor drivers that are imported and provide torque control in military stabilization systems and to reduce foreign dependency by using domestic and national motor drivers in these systems. Since high precision torque control is aimed even at low speeds in military applications, field-oriented control was used. Due to the high military expectations, sensor control was preferred, and an absolute encoder was preferred as a position sensor. This method can be applied in many areas with different power and torque requirements. Stabilization systems were chosen as the application. Based on filed-oriented control, a national control algorithm has been applied, and an infrastructure adaptable to the power and torque requirements of the application to be used has been established. In this context, TMS320F28069M type numbered processor from Texas Instruments (TI) company, and the trial card was used as controller. Inverter design is implemented with modular circuits of TI company, and MOSFET switches are used. Algorithm development studies were carried out in MATLAB/Simulink environment. An absolute encoder is used to increase sensitivity. With this encoder, absolute position information can be accessed and position information is not lost even if there is a power cut. The position information obtained from here is transferred to the field-oriented torque control loop. By carrying out the load test, the moment ripple in the steady-state and its performance at the rated load have been determined. Different communication methods have been used to determine the interaction of the performance of the system. Since it was seen that the method called "external mode" which works over Simulink, became insufficient and did not work efficiently as the algorithm became more complex, CAN communication was started, and it was ensured that the instantaneous torque value could be controlled with the P and I coefficients that can be changed instantly via the PI controller. Input and output feedbacks were instantly observed via Simulink, algorithms were written in Simulink, and all hardware was communicated with Simulink via CAN communication. The effect of switching frequency on torque ripple was investigated with appropriate P, I coefficients, and as a result of the optimization, this ripple was reduced below the values expected by the standards. In the second part of the study, compliance checks were made in terms of military standards, and temperature and electromagnetic compatibility tests were completed. Since a device with a chassis was not aimed directly, mechanical compatibility tests were not needed. Temperature tests were carried out between -40°C and +55°C in accordance with the standards, and the distortions observed in the clock frequency of the processor at values close to the limit temperatures in the first tests were overcome by the use of an external oscillator. Although an increase in torque fluctuation was observed in this test, the maximum value remained below 3%. In electromagnetic compatibility tests, MIL-STD 461 CE101 and CE102 tests were carried out, and the noise emitted by the device in various frequency ranges was measured. Although the noise remained above the acceptable level in the first CE102 test, the circuit passed the tests successfully with the appropriate filter design. In addition, with the study, infrastructure was created for the selection of materials for further studies. As a result, within the scope of this thesis, low torque vibration, high precision field-oriented torque control of a permanent magnet synchronous motor in accordance with military temperature and EMC standards have been realized. With the output of the thesis, domestic equivalents of hardware and software products supplied from abroad and used in national applications have been obtained, contributing to the country's economy and reducing foreign dependency in this area.