| 摘要 |
PURPOSE:To stabilize energy accumulated in a choke by a method wherein a second smoothing capacitance C2 is charged by electric current fed back from a part of an inverter and C2 voltage is intermittently applied to a choke between homopoles of commutative output of a commercial power source VS and a first smoothing capacitance C1. CONSTITUTION:In addition to smoothing capacitance C1 of an input terminal of an inverter INV, capacitance C2 which is charged lower than voltage VC1 and the peak of a commercial power source C2 is provided and intermittently applied to a choke L0 between an output terminal of a full-wave rectifier DB and capacitance C1 via a transistor Q0. While the device Q0 is on, VC2 is added to L0, and while the device Q0 is off, self induction voltage of L0 overlaps the output of the all-wave rectifier so as to charge C1. As a result, while momentary voltage of VS is low, input current Iin from VS does not resume so that current of a discharge lamp L2 is stable, increasing input rate and decreasing higher harmonic component of input current. This constitution keeps voltage to be applied to L0 almost constant, stabilizes accumulated energy, compacts L0 and reduces pressure of a device 3. |
