| 摘要 |
PROBLEM TO BE SOLVED: To reduce the harmonic distortion of an input current. SOLUTION: A period T1 in which switching elements Q1, Q2 are simultaneously turned on, a power is supplied from a capacitor C1 to a load circuit, and an energy is stored in an inductor L1; a period T2 in which the element Q1 is turned on, the energy stored in the inductor L1 is supplied to the load circuit, and an input current Iin is captured from an AC power source AC; and a period T3 in which any of the switching elements Q1 to Q4 are not turned on, the energy stored in the inductor L1 is supplied to the load circuit, and the capacitor C1 is charged through an AC power source AC; are changed in a time series. Here, when the period T1 is changed in time by a control circuit (not shown) so as to become a direct proportional to the voltage Vs of the power source AC, the harmonic distortion can be reduced by decreasing the input current Iin at a zero-crossing point by shortening the period T1 at the zero-crossing point of the voltage Vs. |
