Power supply apparatus and an air conditioner using the same

摘要

A high capacity power supply apparatus effectively suppresses harmonics while maintaining a high output voltage and high power factor by means of a simple configuration. A reactor (8) is connected between an AC power source (1) and the AC input terminal of the bridge rectifier (6). A capacitor (10) is connected between the AC input terminal and DC output terminal of the bridge rectifier (6) through an intervening two-way switch (9). A phase detector (12) detects when the voltage of the AC power source (1) crosses zero. A two-way switch driver (14) drives the two-way switch (9) based on a signal from the phase detector (12). The inductance of the reactor (8) is lower when the input current to the reactor (8) is greater than a specified level than when the input current is below the specified level. A voltage drop and current phase delay can thus be prevented in the reactor when the load is high, and a drop in the output voltage and power factor can be avoided. <IMAGE>