Converter circuit, and motor drive controller equipped with converter circuit, air conditioner, refrigerator, and induction cooking heater

摘要

Provided are a converter circuit which can be made compact and lightweight while reducing switching loss, and a motor drive controller equipped with the converter circuit, an air conditioner, a refrigerator, and an induction cooking heater. A converter circuit comprises a rectifier (2), a step-up converter (3a) having a step-up reactor (4a), a switching element (5a) and a reverse current prevention element (6a), a step-up converter (3b) having a step-up reactor (4b), a switching element (5b) and a reverse current prevention element (6b) and being connected in parallel with the step-up converter (3a), a switching control means (7) for controlling the switching elements (5a, 5b), and a smoothing capacitor (8) provided at the output of the step-up converters (3a, 3b), wherein the switching control means (7) switches the current mode of a current flowing through the step-up reactors (4a, 4b) to any one of a continuous mode, a critical mode or a discontinuous mode based on predetermined conditions.