| 摘要 |
<p>Induction motor drive apparatus controls actual speed of an induction motor (4) in relation to command speed by driving signals applied to the motor (4) and is such as to limit the torque of the motor (4) in a low speed operating region, by limiting a deviation signal (command speed minus actual speed), to less than a prescribed value.
<??>The apparatus includes a deviation signal generator (7,8), a torque limit signal generator (17), an amplitude controller (16) for controlling the amplitude of the deviation signal when a torque limit signal (TLS) is present, a slip signal generator (10) which generates a slip signal (Vso) of a constant voltage of polarity depending upon the rotational direction of the motor (4), an adder (11) for adding an actual speed signal (Vn) to the slip signal (Vso), and a multiplier (18) for multiplying the output (Vs min ) of the amplitude controller by the output (Vso + Vn) of the adder (11). The driving signals have a frequency proportional to the output (Vso + Vn) of the adder (11), and an effective value dependent upon the output (Vs min . Vso + Vn) of the multiplier (18). </p> |
