Resonant inverter circuit

• US 6,643,157 B2
• Filed: 04/05/2002
• Issued: 11/04/2003
• Est. Priority Date: 04/26/2001
• Status: Expired due to Fees

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Furukawa, Katsuhiko, Shinohara, Sadao
• Primary Examiner(s): Patel, Rajnikant B.
• Application Number:
  US10/115,979
• Publication Number:
  US 20020159281A1
• Time in Patent Office: 578 Days
• Field of Search: 363/132, 363/127, 363/98, 363/131, 363/97, 363/95, 363/17, 363/16
• US Class Current: 363/132
• CPC Class Codes: H02M 7/5387 in a bridge configuration
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A resonant inverter circuit is provided which can be made lighter in weight and smaller in capacity. With a main circuit in steady mode, IGBT of an auxiliary circuit are controlled and the energy of an electric current is stored in a resonant inductance. Next, snubber capacitors are charged and discharged by means of an electric current. At this time, the voltages across both terminals of IGBT corresponding with the snubber capacitors being charged becomes zero, and ZVS is achieved. Furthermore, when the snubber capacitors being discharged have been completely discharged, and free wheeling diodes and IGBT corresponding with these snubber capacitors conduct, both the voltages across both terminals of the IGBT and the electric current become zero and ZVS and ZCS are achieved.

Claims

1. A resonant inverter circuit comprising:

six main switching elements which either conduct or are cutoff by means of switching control, wherein three sets of two main switching elements which comprise each phase of a three phase bridge are connected in the three phase bridge, and each set of the main switching elements is connected in series to both terminals of a power source;

six free wheeling diodes connected in parallel between two terminals of each of the main switching elements;

six snubber capacitors connected in parallel between two terminals of each of the main switching elements;

a three phase output terminal for connecting a load, connected respectively to a connection point of the two main switching elements comprising each of the sets;

a bridge circuit having six auxiliary switching elements for causing an electric current to flow in a single direction, wherein three sets of two auxiliary switching elements are connected in a three phase bridge, and connection points common to the two auxiliary switching elements which comprise each set of the auxiliary switching elements are connected respectively to the three phase output terminal; and

a resonant inductance forming a resonant circuit with the snubber capacitors, connected to an opposite terminal to a terminal connected to the connection point of the auxiliary switching elements.

2. An inverter circuit according to claim 1, wherein one of the auxiliary switching elements of each set of the auxiliary switching elements includes a unidirectional switching element which only conducts electric current in a direction flowing into the connection point of the auxiliary switching elements, and

another auxiliary switching element of each set of the auxiliary switching elements includes a unidirectional switching element which only conducts electric current in a direction flowing out from the connection point of the auxiliary switching elements.

3. An inverter circuit according to claim 2, wherein the unidirectional switching elements are elements having a withstand voltage greater than a power source voltage of the power source, in both forward and backward directions.

4. An inverter circuit according to claim 2, wherein the unidirectional switching elements are insulated gate bipolar transistors,

each auxiliary switching element comprises the insulated gate bipolar transistor and a diode, and the diode is either one of a diode in which an anode terminal is connected to a collector terminal of the insulated gate bipolar transistor, and a diode in which a cathode terminal is connected to an emitter terminal of the insulated gate bipolar transistor.

5. An inverter circuit according to claim 2, wherein the unidirectional switching elements are metal oxide semiconductor field effects transistors,

each auxiliary switching element comprises the metal oxide field effects transistor and a diode, and the diode is either one of a diode in which an anode terminal is connected to a drain terminal of the metal oxide field effects transistor, and a diode in which a cathode terminal is connected to a source terminal of the metal oxide field effects transistor.

6. An inverter circuit according to claim 2, wherein the unidirectional switching elements are reverse blocking thyristors.