| 摘要 |
PURPOSE:To effect operation with a high efficiency by a method wherein the fluctuating level of a system voltage is detected and the control of a converting device is switched when the level has exceeded a set value. CONSTITUTION:A detector 5, connected to a power system 1, measures the voltage of the power system for a given period of time at all times to detect the level of the fluctuation of the voltage. When disturbance is generated in the power system 1, the level of the fluctuation of the same has exceeded a set value and the level can not be followed by pulse width control, a switching signal is sent to a switching device 6 and control function is switched to PWM control. According to this method, stabilized operation can be continued against the fluctuation of the system voltage. Thereafter, when the fluctuation of the system voltage is eliminated and the level is settled within a range, in which the operation under the pulse width control is possible, the detector 5 sends a switching signal to the switching device 6 and the control of the operation is returned to the pulse width control to continue the operation. |
