| 摘要 |
PURPOSE:To provide any frequency output being not related to an input power source by switching first-fourth switching elements at a high frequency, switching first and second switching elements alternately, and switching the third and fourth switching elements in normal and reverse directions in alternating periods at a low frequency. CONSTITUTION:First-fourth switching elements S1, S2, S3, and S4 are all turned on and off at a high frequency. In this case the elements S1 and S2 switched alternately so that the element S1, during the first polarity of an input power source VS, and the element S2, during the second polarity, act respectively as choppers so as to obtain DC voltage at a smoothing capacitor C1. During the first period, when the element S5 and the element S2 are turned on simultaneously, current flows in one direction of a load circuit R, and during the second period, when the element S6 and the elements S1 are turned on simultaneously, the current flows in a reverse direction of the load circuit R. In this way, low frequency power is supplied to the circuit R, the first and second periods being as alternating cycle. Thereby it is possible to supply low frequency power, having any cycle TLF and no relation to the cycle T5 of the input power supply VS, to the circuit R. |
