| 摘要 |
PROBLEM TO BE SOLVED: To make servo-motor control changeable to force feed-back control with respect to a driver for an injection mechanism. SOLUTION: When the operation of a circuit 53 is changed to speed control by using a signal PST, a clamp voltage according to a difference between a command voltage PV and a detection voltage PH that corresponds to the pressure on resin is fed from a circuit 53 to an amplifier 51. When an input voltage Vr is over the clamp voltage, the clamp voltage is generated from the amplifier 51 and multiplied by signals that are generated from POM's 6 and 7 according to a rotor position in D/A converters 10 and 11, and current commands RCT to TTC are generated for each phase of the motor. Then, PWM signals PA to PF are generated on the basis of each phase current command and each detected phase voltage to drive a servo motor through an inverter. In feed-back control, the voltage can be changed by the clamp voltage in accordance with a difference between the command voltage PV and the detected voltage PH in a way that the detection voltage PH is made equal to the command voltage PV. |
