PURPOSE: To provide a DC/AC converter in which ripple is suppressed by connecting an LC filter, tuned with n-th higher harmonic (n is an odd number) of switching frequency, in parallel with a smoothing capacitor thereby reducing the capacitance of the smoothing capacitor.
CONSTITUTION: Basic wave component of ripple current produced through switching of a transistor 4 is absorbed through an LC resonance circuit of a reactor 2 and a capacitor 3. Since main component of ripple has carrier frequency, it can be absorbed through the LC resonance circuit of the reactor 2 and the capacitor 3. When current ripple of a chopper or a PWM inverter is absorbed through the LC resonance circuit, capacity of smoothing capacitor can be reduced significantly resulting in a downsized DC/AC converter having prolonged service life.
SONODA SUMITOSHI
YAMAMOTO EIJI
