Commutatorless motor

Abstract

Abstract PURPOSE: To prevent shocking, hunting, etc. when shifting a position detecting operation to a separately-excited inverter operation, by temporarily performing a constant speed controlled operation at shifting speed and shifting to the invertion operation in accordance with the coincidence of a position detection signal with a commutation control signal. CONSTITUTION: Normally, a synchronous motor SM is energized from a thyristor Leonard main circuit LEO and a power inverter SRC and controlled by a signal from a calculator 8 which converts the detection signal of an induced voltage detection circuit 6 into a logic signal corresponding to the position of the rotating megnetic field of the motor. To reduce the output voltage of a variable resistor 1 to decrease the speed of the motor, the output voltage of the variable resistor is compared with that of a speed increase/decrease circuit 9 by a comprator circuit 14. When the output voltage of the resistor 1 has reached a predetermined level, the output of the circuit 9 is applied as a speed reference input to an operational amplifier SC. The signal of the speed increase/ decrease circuit 9 is previously adjusted so that the rotational frequency corresponding to the position detection signal at the time of the application of the output of the circuit 9 coincides with the rotational frequency of the separately-excited inverter operation at the time of switching to the output signal of a ring counter 11. Thereby, the inverter operation can be started without changing the rotational frequency of the motor SM. COPYRIGHT: (C)1979,JPO&Japio

Inventors

• 👤 Takashi Morishita
• 👤 Osamu Kawasaki

Bibliographic Details