| 摘要 |
PROBLEM TO BE SOLVED: To provide an active filter device with a little loss and small noise. SOLUTION: In an active filter device 24, resonance capacitors 10c-15c are respectively connected in parallel to main switching devices 10a-15a to which diode devices 10b-15b are respectively connected in reverse-parallel and, further, auxiliary switching devices 37-42 and resonance choke coils 34-36 are connected to the main switching devices 10a-15a. When the auxiliary switching devices 37-42 are turned on, resonance circuits are formed. If the main switching devices 10a-15a are turned on/off when resonance currents flow between the resonance capacitors 10c-15c and the resonance choke coils 34-36 and the voltages of the resonance capacitors 10c-15c are lowered, a loss can be reduced. If primary windings 31a-33a are provided in routes through which the resonance currents flow and voltages are induced in secondary windings 31b-33b so as to have a main capacitor 22 charged by the resonance currents, the loss can be further reduced. |
