Power controlling apparatus

• US 20050105308A1
• Filed: 09/27/2004
• Published: 05/19/2005
• Est. Priority Date: 09/29/2003
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Asai, Takamasa, Okuda, Tatsuya, Urakabe, Takahiro, Gotou, Sigetada
• Granted Patent: US 7,075,271 B2
• Time in Patent Office: Days
• US Class Current: 363/65
• CPC Class Codes: H02M 7/219 in a bridge configuration
• CPC Class Codes: H02M 7/797 using semiconductor devices only

Abstract

The invention provides an apparatus for bi-directional power conversion between a DC circuit and an AC circuit, which inexpensively and simply suppresses generation losses of elements and reduces heat generation, wherein a voltage obtained by dividing the U-phase voltage Vu is compared with a voltage obtained by dividing the voltage vpn of a DC circuit by a comparator CP1, and the MOSFET UFETh is turned on at the output timing thereof, and a voltage obtained by dividing the V-phase voltage Vv is compared with a voltage obtained by dividing the voltage Vpn of a DC circuit by a comparator CP2, and the MOSFET UFETh is turned off at the output timing thereof.

Claims

1. A power controlling apparatus provided with a power converting circuit which is connected between a DC circuit and an AC circuit and composed of a switching element enabling power supply bidirectionally and a diode connected to the switching element in parallel thereto, the same power converting apparatus that executes an inverter operation which, by controlling the switching element, DC power from the DC circuit is converted to AC power and is outputted to the AC circuit and a rectification operation which, by the diode, AC power from the AC circuit is converted to DC power and is outputted to the DC circuit,

wherein the switching element connected in parallel to the diode is caused to supply power in the same direction as the corresponding diode in a period of time of power supply made by the diode in the rectification operation.

2. A power controlling apparatus according to claim 1, wherein the power converting circuit is made into a three-phase power converting circuit in which an assembly, in which a high-potential side switching circuit and a low-potential side switching circuit, each of which being composed of a parallel connector of the switching element and diode, are connected in series, is connected in three phases between a high-potential side terminal and a low-potential side terminal of the DC circuit, and respective series connection points of the high-potential side and low-potential side switching circuits are connected to respective phase terminals of the three-phase AC circuit.

3. A power controlling apparatus according to claim 2, further comprising first detecting means for detecting voltage of respective phases of the three-phase AC circuit and voltage of the DC circuit and for detecting power supply commencement timing of the respective diodes through comparison operations on the basis of the voltage detection values, wherein the switching element connected to the corresponding diodes in parallel thereto is turned on with the power supply commencement timing detected by the first detecting means.

4. A power controlling apparatus according to claim 3, further comprising second detecting means for detecting voltage of a phase (hereinafter called the “

next phase”

) delayed by a (⅔

)π

phase angle from the phase (hereinafter called the “

corresponding phase”

) on which the switching element has been turned on and voltage of the DC circuit, and for detecting power supply commencement timing of the next phase diode through comparison operations on the basis of these voltage detection values, wherein the corresponding diode switching element is turned off with the power supply commencement timing detected by the second detecting means.

5. A power controlling apparatus according to claim 4, further comprising delaying means for delaying the timing of turning off the corresponding phase switching element by a prescribed duration of time in the power supply period of the corresponding phase diode.

6. A power controlling apparatus according to claim 5, wherein, by varying the delay time for delaying by the delaying means in accordance with the frequency of the AC circuit, the power supply period expressed in terms of a phase angle of the switching element is made constant regardless of the frequency.

7. A power controlling apparatus according to claim 3, further comprising ON time setting means for turning off the switching element in a prescribed ON-time that is set in the power supply period of a diode connected to the corresponding switching element in parallel thereto after turning on the corresponding switching element, wherein, by varying the ON-time set by the ON-time setting means in accordance with the frequency of the AC circuit, the power supply period expressed in terms of a phase angle of the switching element is made constant regardless of the frequency.

8. A power controlling apparatus according to any one of claims 1 through 7, wherein the DC circuit includes a DC power source that can be charged and discharged, and the AC circuit includes a generator/motor which converts mechanical power to AC power and AC power to mechanical power.

9. A power controlling apparatus according to any one of claims 1 through 8, wherein the switching element is MOSFET.

10. A power controlling apparatus according to claim 9, wherein the diode is a parasitic diode of the MOSFET.