| Summary: | 碩士 === 國立臺灣科技大學 === 電機工程系 === 106 === This thesis aims to design three-phase permanent-magnet synchronous motor (PMSM) drive powered by grid and solar hybrid energy for aquatic breeding aerators. The proposed system mainly contains two parts, namely the driver and its power supply. The former is a PMSM driven by three-phase, three-arm power inverter using voltage space vector pulse-width modulation to enhance the utilization ratio of dc-link voltage. In addition, linear hall-effect sensors are used to detect the rotor position and rotational speed to facilitate current and speed closed-loop controls for efficiency improvement. On the other hand, a bridge rectifier and single-phase full-bridge power converter are built to establish the dc power supply for dc-link voltage of 48.0V from power grid. Moreover, a two-arm interleaved boost converter along with the maximum power point tracking are proposed to improve the efficiency of power conversion for solar energy generation. The grid and solar hybrid power supply can reduce the utility power consumption and thereby save the energy.
The 32-bit microprocessor, XMC1404, is adopted as the system core. All control strategies are accomplished with C language. Experimental evaluation of the three-phase PMSM drive system is conducted with three different cases of power supply. Specifically, the scenarios of the driver powered by dc source, grid as well as grid and solar hybrid energy. At motor speed of 1500rpm, experimental results show that when a dc-link voltage of 48.0V is provided by a dc source, the current and power at inverter input are 8.1A and 390.0W, respectively. The inverter output power is 366.0W. The corresponding PMSM torque, phase current and its total harmonic distortion (THD) are 2.08N-m, 17.1A and 4.4%. The efficiencies of inverter and PMSM are 93.8% and 89.2%, respectively, resulting in the overall efficiency of 83.7%. Besides, when the dc-link voltage of 43.6V is supplied by power grid, the input and output powers of inverter are 183.1W and 167.8W, respectively. This yields the inverter efficiency of 91.6%. Finally in grid and solar hybrid power supply case, the solar power subsystem provides 68.5W to the dc-link voltage of 46.0V, the output power of single-phase full-bridge power converter is reduced from 272.3W to 204.0W, with the inverter output power of 240.2W. This gives the inverter efficiency of 88.2%. The corresponding PMSM phase current and its THD are 11.2A and 5.4%. In short, the feasibility of the proposed system is verified experimently.
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