CONVERTER CIRCUIT TO WHICH SINE WAVE IS INPUTTED

摘要

A converter circuit which is constituted of a rectifying diode bridge (1) connected to an AC power source through a filter (F), a circuit comprising an inductor (L1) connected between the output terminals of the bridge (1), a switching element (Tr1), and a reverse-blocking diode (D1), and a control circuit (3) comprising a smoothing capacitor (Cd) charged with the energy stored in the inductor (L1) and a comparator (36) which controls the element (Tr1) by comparing the signal of a circuit (31-34) which detect and amplify the deviation of a (DC) output voltage (Vd) from a set voltage (Vs) with a triangular carrier (36). The element (Tr1) is turned on/off using a carrier frequency. While the element (Tr1) is on, energy is stored in the inductor (L1) through the bridge (1) and, while it is off, the capacitor (Cd) is charged with the stored energy. Since the current of the element (Tr1) starts to flow from the time when the input voltage is low regardless of the voltage of the capacitor (Cd), the input current is a sine wave.