Converter circuit and motor drive control apparatus, air-conditioner, refrigerator, and induction heating cooker provided with the circuit

Abstract

A converter circuit capable of being compact and light-weight and capable of reducing switching loss, a motor drive control apparatus, an air-conditioner, a refrigerator, and an induction heating cooker provided with the circuit. The converter circuit including: a step-up converter including a rectifier, a step-up reactor, a switching element, and a reverse current prevention element; a step-up converter having a step-up reactor, a switching element, and a reverse current prevention element and connected in parallel with the step-up converter; switching control unit that controls switching elements; and a smoothing capacitor that is provided at the output of the step-up converters. The switching control unit switches the current mode of the current flowing through the step-up reactors into any of a continuous mode, a critical mode, and a discontinuous mode based on a predetermined condition.

1 - 8 . (canceled) 
     
     
         9 . A converter circuit, comprising:
 a rectifier that rectifies an AC voltage;   at least a converter section that is connected with an output of said rectifier and has a reactor, a switching element, and a reverse current prevention element;   switching control means that controls said switching element; and   a smoothing capacitor that is provided at an output of said converter section, wherein   at a predetermined value or in a predetermined range of an output voltage of said converter section, a current mode of a current flowing through said reactor is controlled by said switching control means and is one of at least two modes among a critical mode, a discontinuous mode, and a continuous mode.   
     
     
         10 . The converter circuit of  claim 9 , further comprising:
 one or more converter sections that are connected with the output of said rectifier, each of the one or more converter sections has a reactor, a switching element, and a reverse current prevention element, and each of the one or more converter sections is connected with said at least one converter section in parallel.   
     
     
         11 . The converter circuit of  claim 10 , wherein
 said switching control means controls switching of said switching element and said switching element in each of the one or more converter sections so as to create a predetermined phase difference in the current flowing through said reactor and said reactor in each of the one or more converter sections.   
     
     
         12 . The converter circuit of  claim 11 , wherein
 said switching control means controls switching of said switching element and said switching element in each of the one or more converter sections so that the phase difference of the currents flowing through said reactor and said reactor in each of the one or more converter sections randomly varies within a predetermined range.   
     
     
         13 . A motor drive control apparatus, comprising:
 the converter circuit of  claim 9 ;   an inverter circuit that converts a DC output voltage of said converter circuit to an AC voltage; and   inverter drive means that drives said inverter circuit.   
     
     
         14 . An air-conditioner, comprising:
 the motor drive control apparatus of  claim 13 ; and   a motor that is driven by said motor drive control apparatus.   
     
     
         15 . A refrigerator, comprising:
 the motor drive control apparatus of  claim 13 ; and   a motor that is driven by said motor drive control apparatus.