| 摘要 |
PURPOSE:To rotatably drive an induction motor at an arbitrary speed by controlling an inverter on the basis of a torque control signal utilizing a sawtooth wave in addition to the amplitude and direction of a primary crossing magnetic flux vector. CONSTITUTION:Magnetic flux detecting means 15 calculates a primary crossing vector on the basis of a primary voltage and a primary current at the time of rotatably driving an induction motor 1, and torque detecting means 18 calculates a momentary torque. A comparator 3 outputs a magnetic flux signal and a region discriminator 6 outputs a region signal on the basis of the primary crossing vector to a controller 19. A momentary torque is compared by a subtractor 20 with the command value of a torque instructing circuit 21, proportionally integrated by a PI controller 22, and input to a comparator 23. The comparator 23 compares the output of the controller 22 with a sawtooth wave W, and a rectangular wavelike torque signal is output to the controller 19. A switching signal corresponding to a primary voltage vector selected by the controller 19 is output to an inverter 2. |
