Research On Voltage-Adjustment Equipment With Thyristors For Motors With Unsymmetrical Load

The motors with unsymmetrical load such as fans and water pumps are used widely.They will consumes a great deal of power energy, if controlled by accommodating the bafflesand valves. In this paper, an energy-saving technology based on thyristor controlling isadvanced, including the motors' energy-saving, soft startup, scouting state, and safeguardingmotor. Therefore, the research has not only the important science meaning, but also the utilityvalue. The alternating-voltage theory of the fans and water pumps is analyzed in this paper. Theload for the designed equipment is the motor, whose voltage is 380V and power is 37KW. Themain circuit and the controller are designed. Then, the alternating-voltage arithmetic is alsoadvanced based on the power factor and PID controlling method. Finally, the modeling ofthe whole circuit is established with MATLAB and the simulation is made when thethyristors are trigged at different phase-shift angles. The result shows that alternatingvoltage adjustment costs little and takes effect evidently. But it has the disadvantage ofthe abundant harmonics.