PURPOSE: To decrease a power loss and to simplify the constitution of an apparatus by causing first and second switching elements to function alternately as chopper and inverter switching elements for each positive or negative half cycle of AC power.
CONSTITUTION: For a half cycle of positive AC power VS, a transistor Q1 serves both as chopper and inverter switching elements and a transistor Q2 functions only as an inverter switching element. For a half cycle of negative AC power VS, the transistor Q2 serves both as chopper and inverter switching elements and said transistor Q1 functions only as an inverter switching element. Thus, respective transistors Q1, Q2 function alternately as a chopper switching element for each half cycle of AC power VS.
MAEHARA MINORU
MITANI MASATAKA
MATSUSHITA ELECTRIC WORKS LTD