| 摘要 |
PURPOSE:To match a voltage applied to a drive and control circuit with an input voltage to a control power supply circuit and to make a voltage-matching transformer, etc., unnecessary by providing a rectifier and smoothing circuit obtaining a control power from the oscillating current of an LC series resonance circuit for control power and by setting the circuit constant of said LC series resonance circuit appropriately. CONSTITUTION:In a control power supply circuit A4, when switching elements Q1 and Q2 are respectively ON and OFF after starting, a sine waved oscillating current I1 flows through an LC series resonance circuit KY1 for control power according to the path of DC power E-inductance element L1-capacitor C3. Thus, said control power supply circuit is provided with the LC series resonance circuit KY1 for control power and with a rectifier and smoothing circuit SH1 obtaining said control power from the oscillating current I1 of said LC series resonance circuit KY1 after starting. In this manner, the circuit constant of said LC series resonance circuit KY1 is set appropriately so that it is possible to contrive to match a voltage applied to a drive and control circuit DR with an input voltage to the control power supply circuit A4. Therefore, a voltage- matching transformer and a current limiting resistor can be made unnecessary. |
