| 摘要 |
PURPOSE:To improve the rapid response of a high-capacity machine, by detecting the coercive force and revolution speed of an electric motor and by controlling the frequency of ignition pulses and the magnitude of the DC voltage of an inverter so that the instantaneous value of a magnetic flux interlinkage number is constant. CONSTITUTION:A variable-voltage DC power source 3 and an inverter 4 are connected to an induction motor 6', the angular velocity omegar of which is detected by a detector 20 and compared with a speed command. The angular velocity is applied to a calculator 17 together with a rotor magnetic flux interlinkage number phi0 set by a setting unit 24. A current level I0 proportional to the magnitude of the coercive force is thus determined. A comparator 18 compares the current level with an actual current determined by a detector 8 to control the voltage of the DC power source 3. Another calculator 21 sets an angular speed on the basis of the current level I0 and the magnetic flux interlinkage number phi0 to control the frequency of ignition pulses through a pulse generator 23. According to this constitution, the magnitude of main magnetic flux is controlled to be constant. Rapid response speed control can thus be easily effected. |
