| 摘要 |
A bridge connection of electric valves each comprises a reverse parallel connection of a semi-conductor switching element and a diode. A DC power is converted to an AC power by PWM control. A voltage detection device is probided to detect an output voltage of the inverter. The pulse width of the pulse width modulation signals is corrected in accordance with the comparison of the detected voltage and the PWM signal. A drive circuit, which provides a dead time during which the switching elements of the electric valves connected in series uses the corrected PWM signal for driving the switching element.
|
