POWER CONVERSION APPARATUS

• US 20140226380A1
• Filed: 09/20/2012
• Published: 08/14/2014
• Est. Priority Date: 09/20/2012
• Status: Active Grant

• Current Assignee: Fuji Electric Company Limited (Fuji Electric Systems Company Limited)
• Original Assignee: Fuji Electric Company Limited (Fuji Electric Systems Company Limited)
• Inventors: Kawashima, Tetsuya
• Granted Patent: US 8,934,274 B2
• Time in Patent Office: Days
• US Class Current: 363/97
• CPC Class Codes: H02M 1/0009 Devices or circuits for detecting current in a converter
• CPC Class Codes: H02M 7/48 using discharge tubes with control electrode or semiconductor devices with control electrode
• CPC Class Codes: H02M 7/53873 with digital control
• CPC Class Codes: H02M 7/539 with automatic control of output wave form or frequency H02M7/5375 - H02M7/5387 take precedence

Abstract

A current flowing into one of half-bridge circuits of a power semiconductor module (10) is detected by corresponding one of current detection circuits (11a and 11b to 11f) through a current detection terminal provided in corresponding one of semiconductor switching devices (Q1 and Q2 to Q6) forming the half-bridge circuits and a current detection terminal provided in corresponding one of flywheel diodes (D1 and D2 to D6) back-to-back connected to the corresponding one of the semiconductor switching devices (Q1 and Q2 to Q6). A pulse voltage waveform indicating the current detected by the corresponding one of the current detection circuits (11a and 11b to 11f) is held for a predetermined period and converted into a stepwise voltage waveform by use of corresponding one of sample-and-hold circuits (14a, 14b and 14f), so that the voltage held by the corresponding one of the sample-and-hold circuits (14a, 14b and 14c) is transmitted to a control circuit (20) through corresponding one of insulating circuits (14a, 14b and 14c).

Claims

1. A power conversion apparatus characterized by comprising:

a power semiconductor module having one pair or pairs of semiconductor switching devices which are connected in series to form one half-bridge circuit or half-bridge circuits and which are driven to be ON/OFF while being associated with one another, and a plurality of flywheel diodes back-to-back connected to the semiconductor switching devices respectively;

a control circuit which is provided to be separately isolated from the power semiconductor module and which drives the semiconductor switching devices to be ON/OFF respectively;

current detection circuits which detect currents flowing in the half-bridge circuits through current detection terminals provided in ones of the semiconductor switching devices forming the half-bridge circuits in the power semiconductor module and current detection terminals provided in the flywheel diodes back-to-back connected to the ones of the semiconductor switching devices;

sample-and-hold circuits which hold voltages corresponding to the currents detected through the current detection circuits for a predetermined period of time; and

insulating circuits which transmit the voltages held by the sample-and-hold circuits to the control circuit.

2. A power conversion apparatus according to claim 1, wherein:

each of the current detection circuits includes first and second current detectors which detect the current flowing in the corresponding semiconductor switching device and the current flowing in the corresponding flywheel diode respectively, and an adder which adds up outputs of these first and second current detection circuits.

3. A power conversion apparatus according to claim 2, wherein:

the first and second current detectors have current correction circuits which can change voltages of the current detection terminals provided in the semiconductor switching device and the flywheel diode respectively and correct the currents detected through the current detection terminals.

4. A power conversion apparatus according to claim 1, wherein:

the sample-and-hold circuits sample output signals of the current detection circuits in sync with switching periods of the semiconductor switching devices and hold the output signals until next sampling timing.

5. A power conversion apparatus according to claim 1, wherein:

the power semiconductor module has six semiconductor switching devices forming three half-bridge circuits corresponding to respective phases of a three-phase AC power source, and six flywheel diodes to form an inverter apparatus for a three-phase AC load.

6. A power conversion apparatus according to claim 1, wherein:

the power semiconductor module has one pair or two pairs of the semiconductor switching devices forming one half-bridge circuit or two half-bridge circuits, and the flywheel diodes back-to-back connected to the semiconductor switching devices so that the power semiconductor module and an output circuit connected to an output terminal of the one half-bridge circuit or output terminals of the two half-bridge circuits through inductance form a converter apparatus for controlling a current flowing in the inductance to obtain a predetermined voltage in the output circuit.

7. A power conversion apparatus according to claim 1, wherein:

voltage signals given from the sample-and-hold circuits through the insulating circuits are inputted to the control circuit after gains and offsets of the voltage signals are regulated through voltage regulation circuits.