The master thesis discusses the use of suitable software and hardware for the control of multiphase machines.
The introduction presents the model of the classical three-phase synchronous motor, with emphasis on the voltage model in the rotor field coordinate system, as a base for FOC model. This is followed by presentation of two types of multi-phase motors, namely the triple three-phase-coupled and de-coupled motor.
The central part describes software and hardware (9-phase inverter) for control of multi-phase motors. In the beginning, the theory of pulse width modulation with the emphasis on vector modulation or SVM is explained, and then the generation of PWM using a microcontroller is presented in more detail.
Then, different types of control for both types of motors are presented and their performance is demonstrated in the real system. In the case of a motor without electromagnetic coupling, we implemented the control of the current of one system, the control of the average current of the three systems and the control of the current of each individual system. The last option proved to be the most accurate and efficient. In the case of a electromagnetic coupling between the systems, we implemented the control of the average current of the three systems, the control of the current of each individual system, and the control of the average current with additional controllers of the difference from the average for each system. In this case, the approach with the main average controller and additional differential controllers was most suitable as only this option ensures a good system response and does not cause current asymmetry.
Finally we also made an analysis of the influence of the delay of the PWM triggering between the individual three-phase systems on the supply current waveform and the analysis of the motor's operation in the event of a failure of one three-phase system in the motor.
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