| Summary: | 碩士 === 國立臺灣海洋大學 === 電機工程學系 === 103 === This thesis proposes a novel predictive current control, called simplified model-free predictive current control (SMFPCC), for six-switch three-phase (SSTP) inverter-fed interior permanent magnet synchronous motor (IPMSM) drive systems. Unlike model-based predictive current control (MBPCC), the proposed method is based on current sensor to achieve the goal of current prediction. In addition, the proposed method does not require the knowledge of motor parameters and the mathematical model of the motor. In other words, it does not need the information of stator resistance, inductance, and back electromotive force.
In addition, to further reduce the calculation of the proposed method, a pre-designed switching table is used to achieve the current predictions under four different switching states. In each switching interval, the predictions of the future stator currents are possible to achieve through measuring the stator currents and recording their current variations under different switching states generated from the SSTP inverter. Since the proposed method belongs to a model-free approach, it is naturally insensitive to motor parameters. Similar to the MBPCC, a switching state is chosen by minimizing a cost function within the present switching interval. The chosen switching state will be applied for controlling the SSTP inverter directly. The advantages of the proposed method are of effectively reducing the computations of the microcontroller and increasing the life expectancy of the inverter due to the low switching frequency.
A digital signal processor, TMS320F2808, made by Texas Instruments Company, is used to execute the SMFPCC and the speed controller. Compared with the MBPCC, the given experimental results show that the proposed SMFPCC has better performance than MBPCC does in terms of the current-tracking under steady-state and transient responses.
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