Controlling method for pole change type induction motor

Abstract

Abstract PURPOSE:To perform control of high efficiency by switching the pole number of the motor and by switching an inverter to the V/F ratio selected appropriately at the time of a low-speed mode of constant torque control in an inverter driving method. CONSTITUTION:A DC power source 1 drives the pole change type induction motor 3 through the intermediary of a PWM inverter 2 and a selecting switch 4. In addition, a speed instruction and a selecting level instruction L given by an instructing unit 5 are compared by a comparator 10 and by the signal thereof the pole number selecting switch 4, as well as a V/F ratio selecting switch 11, is operated. Moreover, the speed instruction is delivered to a function generator 8 and inputted in a modulator 12 through the intermediary of the switch 11, supplying a signal for chopping to the inverter 2. Therefore, the inverter can be switched to the V/F ratio selected properly at the time of low-speed operation, and thus the linear current can be reduced without giving any damage to the constant torque characteristic and the efficiency can be raised.

Inventors

• 👤 Takashi Kitazawa
• 👤 Masakazu Kobata

Bibliographic Details