KR101792824B1 - Bidirectional converter - Google Patents
Bidirectional converter Download PDFInfo
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- KR101792824B1 KR101792824B1 KR1020150151312A KR20150151312A KR101792824B1 KR 101792824 B1 KR101792824 B1 KR 101792824B1 KR 1020150151312 A KR1020150151312 A KR 1020150151312A KR 20150151312 A KR20150151312 A KR 20150151312A KR 101792824 B1 KR101792824 B1 KR 101792824B1
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- stage
- switch
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/483—Converters with outputs that each can have more than two voltages levels
- H02M7/487—Neutral point clamped inverters
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
Abstract
The present invention relates to a bidirectional power conversion apparatus capable of solving a voltage unbalance phenomenon occurring in a multi-level type converter. The bidirectional power conversion apparatus includes a transformer connected to the transformer for receiving a voltage from a high-voltage power source and a transformer connected to the transformer for rectifying the alternating current into direct current or converting the direct current to alternating current, And a second DC link stage connected in series with the first DC link stage to form a neutral point and a second DC link stage connected in parallel to the DC link section to control a voltage level of the DC link section And an inverter unit connected in parallel to the control unit and the DC link unit to convert the DC output from the DC link unit into AC and supply the DC output to the lower stage or rectify the back electromotive force received from the lower stage to DC and supply the DC to the DC link unit.
Description
BACKGROUND OF THE
The main power supply for stable operation of the load is a multi-level converter such as a two-level converter and a three-level converter.
Among them, a three-level converter of a NPC (Neutral Point Clamped) structure is the most commonly used structure of a power conversion device. The 3-level converter is composed of a rectifying section composed of a plurality of diodes, a dc link section composed of a plurality of capacitors, and an inverter section constituted by a plurality of power semiconductor elements and diodes. This three-level converter has a merit that the magnitude of the instantaneous voltage fluctuation (dv / dt) can be reduced by connecting a diode to the neutral point formed in the dc link portion to limit the voltage applied to the power semiconductor.
However, when the rectifying part of the 3-level converter is formed and operated with the same power semiconductor element as the inverter part, not the diode, the voltage between the capacitors constituting the dc link part becomes unbalanced, have.
Therefore, in order to solve this problem, various researches and developments are currently under way in order to balance the voltage of the dc link part. For example, a technique has been developed to adjust the voltage balance of the dc link portion through a control method of a controller that controls a power semiconductor, that is, a control algorithm. However, since the developed control method has a limit value of the voltage that can be synthesized in the power semiconductor of the inverter by using the voltage value of the dc link part, there is a limit to make the voltage of the capacitor of the dc link part to be in a perfectly balanced state.
SUMMARY OF THE INVENTION The present invention is directed to a bidirectional power conversion apparatus capable of solving the voltage unbalance phenomenon of a plurality of DC link stages included in a three-level converter.
The problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.
According to an aspect of the present invention, there is provided a bidirectional power conversion apparatus comprising: a transformer receiving a voltage from a high voltage source and transforming the transformed voltage; a converter connected to the transformer for rectifying AC into direct current or converting direct current into AC; And a second DC link stage connected in parallel with the first DC link stage to store rectified electrical energy and a second DC link stage connected in series with the first DC link stage to form a neutral point, And a voltage control unit connected in parallel to the second DC link stage and controlling the voltage magnitude of the DC link unit, a DC link unit connected in parallel to the DC link unit to convert the DC output from the DC link unit into AC, Or an inverter unit for rectifying the counter electromotive force introduced from the negative terminal to a direct current and supplying the rectified direct current to the direct current link unit .
The voltage control unit may further include a semiconductor switch and a charge storage unit connected in parallel to the semiconductor switch to store electrical energy.
Wherein the charge storage section includes a first charge storage section connected to the anode of the first DC link stage and the neutral point and a second charge storage section connected to the neutral point and the cathode of the second DC link stage, The storage unit and the second charge storage unit may be devices having the same electrical characteristics as the DC link unit.
The converter unit and the inverter unit include a plurality of legs connected in series to a plurality of semiconductor switches in a diode-connected fashion, and the legs may be connected in parallel with each other.
Wherein the leg portion is connected in series with a first switch, a second switch, a third switch and a fourth switch, the first diode is connected in anti-parallel to the connection point of the first switch and the second switch and the neutral point, And a second diode connected in series with the first diode, the second diode being connected in parallel to the connection point of the third switch and the fourth switch and the neutral point.
The bidirectional power conversion apparatus according to the present invention adjusts the voltages of the DC link ends of the upper and lower ends to be balanced so that the inverter section interlocked with the DC link stage can be smoothly operated.
1 is a circuit diagram of a bidirectional power conversion apparatus according to an embodiment of the present invention.
2 is a diagram showing a voltage unbalance state in which the first DC link end of FIG. 1 is overcharged than the second DC link end.
FIG. 3 is a graph showing voltage magnitudes charged in the first DC link stage and the second DC link stage of FIG. 2. FIG.
4 is a diagram showing a voltage unbalance state in which the second DC link end of FIG. 1 is overcharged than the first DC link end.
FIG. 5 is a diagram showing the magnitude of the voltage charged in the first DC link end and the second DC link end in FIG.
FIG. 6 is a diagram illustrating voltage balance states of the first DC link stage and the second DC link stage by operating the first voltage control stage and the second voltage control stage of FIG. 1;
FIG. 7 is a diagram illustrating voltage magnitudes output from the first DC link stage and the second DC link stage of FIG. 6. FIG.
Brief Description of the Drawings The advantages and features of the present invention and methods of achieving them can be made clear with reference to the embodiments described below in detail with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. To fully disclose the scope of invention to a person skilled in the art, and the invention is only defined by the claims. Like reference numerals refer to like elements throughout the specification.
Hereinafter, a bidirectional power conversion apparatus according to an embodiment of the present invention will be described in detail with reference to FIG.
1 is a circuit diagram of a bidirectional power conversion apparatus according to an embodiment of the present invention.
Referring to FIG. 1, a bidirectional
This bidirectional
Here, the
The high-
The
The
The
The
Here, the first DC link stage 31 and the second DC link stage 32 are polarized and not only capable of charging the same amount of charge per hour, but also capable of emitting the same amount of charge per hour It can be an electrolyte capacitor. The first DC link stage 31 and the second DC link stage 32 are provided with a
The
The first charge storage section 41C of the first
The first
The
The
The
Hereinafter, with reference to FIG. 2 to FIG. 7, a description will be given of a state where the first DC link stage and the second DC link stage are changed from the voltage unbalanced state to the voltage unbalanced state.
The
4, when the second DC link stage 32 is overcharged than the first DC link stage 31 and is in a voltage unbalanced state, the semiconductor switches T C7 to T C12 of the
6, when the voltage charged in the first DC link stage 31 and the second DC link stage 32 is out of the set voltage, the
7, the voltage charged in the first DC link stage 31 and the second DC link stage 32 is set by the
While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, You can understand that you can. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.
1: bidirectional power converter 10: high voltage power source
11: Transformer 21: LC filter unit
22: Converter section 30: DC link section
31: first DC link stage 32: second DC link stage
40: voltage control unit 41: first voltage control stage
42: second voltage control stage 50: inverter section
22a, 22b, 22c, 51, 52, 53:
60: filter unit 70:
N: Neutral point
Claims (5)
A converter connected to the transformer for rectifying the alternating current into direct current or converting direct current into alternating current;
A DC link unit connected in parallel to the converter unit and including a first DC link stage storing rectified electrical energy and a second DC link stage connected in series with the first DC link stage to form a neutral point;
A voltage control unit connected in parallel to the DC link unit and controlling a voltage level of the DC link unit;
And an inverter unit connected in parallel to the DC link unit to convert the DC output from the DC link unit into AC and supply the DC output to the lower stage or to rectify the back electromotive force introduced from the lower stage to DC and supply the direct current to the DC link unit However,
Wherein the voltage control unit further includes a semiconductor switch and a charge storage unit connected in parallel to the semiconductor switch for storing the electrical energy,
Wherein the charge storage section includes a first charge storage section connected to the anode of the first DC link stage and the neutral point and a second charge storage section connected to the neutral point and the cathode of the second DC link stage, The storage unit and the second charge storage unit are elements having the same electrical characteristics as the DC link unit,
The voltage control unit charges or discharges the first charge storage unit and the second charge storage unit when the voltage charged in the first DC link stage and the second DC link stage is out of the set voltage, And adjusts the voltage of the first DC link stage and the voltage of the second DC link stage to be balanced.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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KR1020150151312A KR101792824B1 (en) | 2015-10-29 | 2015-10-29 | Bidirectional converter |
Applications Claiming Priority (1)
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KR1020150151312A KR101792824B1 (en) | 2015-10-29 | 2015-10-29 | Bidirectional converter |
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KR20170050151A KR20170050151A (en) | 2017-05-11 |
KR101792824B1 true KR101792824B1 (en) | 2017-11-01 |
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KR1020150151312A KR101792824B1 (en) | 2015-10-29 | 2015-10-29 | Bidirectional converter |
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR20230076248A (en) | 2021-11-24 | 2023-05-31 | 경북대학교 산학협력단 | 3level Neutral Point Clamped Converter for Capacitor Ripple Reduction Using Zigzag Transformer |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
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KR102549613B1 (en) * | 2021-01-28 | 2023-06-29 | 부경대학교 산학협력단 | Devices and Method for Controlling the DC-link Voltage Balancing for Modular Converters |
KR102554948B1 (en) | 2021-06-23 | 2023-07-13 | 경북대학교 산학협력단 | Bi-directional power conversion system with wide DC bus control range |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2010172141A (en) * | 2009-01-23 | 2010-08-05 | Sanken Electric Co Ltd | Three-phase power conversion apparatus |
KR101094002B1 (en) * | 2009-12-16 | 2011-12-15 | 삼성에스디아이 주식회사 | Power converting device |
US20120267902A1 (en) * | 2009-12-24 | 2012-10-25 | Doosan Infracore Co., Ltd. | Power converting device for hybrid |
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2015
- 2015-10-29 KR KR1020150151312A patent/KR101792824B1/en active IP Right Grant
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2010172141A (en) * | 2009-01-23 | 2010-08-05 | Sanken Electric Co Ltd | Three-phase power conversion apparatus |
KR101094002B1 (en) * | 2009-12-16 | 2011-12-15 | 삼성에스디아이 주식회사 | Power converting device |
US20120267902A1 (en) * | 2009-12-24 | 2012-10-25 | Doosan Infracore Co., Ltd. | Power converting device for hybrid |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR20230076248A (en) | 2021-11-24 | 2023-05-31 | 경북대학교 산학협력단 | 3level Neutral Point Clamped Converter for Capacitor Ripple Reduction Using Zigzag Transformer |
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