| 摘要 |
PROBLEM TO BE SOLVED: To provide a control method reducing energy loss and supplying high-capacity electric power in a short term, in a power supply apparatus of a motor-driven injection molding machine including a PWM converter.SOLUTION: A power supply apparatus (1) which converts an external three-phase AC voltage (PW) into direct current voltages (P and N) to supply it to a motor-driven injection molding machine is configured from a PWM converter (2). When controlling the PWM converter (2) by PWM control, a carrier frequency of a PWM signal is increased in an injection process requiring large electric power, and the carrier frequency is decreased in the other process. It is possible to efficiently convert to direct current voltages and stably supply electric power owing to the high carrier frequency in the injection process, and on the other hand, to stably suppress loss of switching of the PWM converter (2) owing to the low carrier frequency in the other process.SELECTED DRAWING: Figure 2 |
