KR101792826B1

KR101792826B1 - Converter

Info

Publication number: KR101792826B1
Application number: KR1020150156128A
Authority: KR
Inventors: 안희원
Original assignee: 삼성중공업 주식회사
Priority date: 2015-11-06
Filing date: 2015-11-06
Publication date: 2017-11-01
Also published as: KR20170053514A

Abstract

The present invention relates to a power conversion apparatus that can confirm the number of output terminals of a power conversion apparatus connected to a load and supply current to the load with an efficient operation method. Such a power conversion apparatus includes a rectifying section for rectifying an alternating current applied by an AC power source, a parallel section connected in parallel to the rectifying section, connected in parallel to the smoothing section and the smoothing section for charging the rectified charge and outputting it as a direct current, A first DC link unit connected to an output terminal of the first converter unit to charge the charge output from the first converter unit, and a second DC link unit connected to the output terminal of the second converter unit, A second DC link part connected to an output terminal of the second converter part for charging the electric charge outputted from the second converter part, and a first DC link part including a first output terminal connected to the load, The first and second DC link units and the second DC link unit measure the current flowing to the load in either the first output terminal or the second output terminal to compare the current ripple and the set ripple with each other The recognition controller is connected.

Description

Power converter

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power conversion apparatus, and more particularly, to a power conversion apparatus capable of checking the number of output terminals for supplying a current to a load and supplying a current to the load in an efficient operation manner according to the number of output terminals identified .

The power conversion apparatus is composed of a rectifier section, a DC section, a plurality of converter modules connected to the DC section, and a DC reactor. Such a power conversion apparatus can convert an AC input from a system into a DC voltage of a desired size in a converter and output it. Because of this feature, the power conversion device is applied to various industrial fields. For example, a power conversion device is installed in a ballast water management system (BWMS) and is used to electrolyze seawater at various concentrations with various DC voltages.

However, the power converter not only generates a large amount of heat in the process of outputting the rectified voltage to a desired voltage, but also generates a lot of EMC radiation noise in the process of converting AC to DC. Moreover, such a problem shortens the service life of the power conversion apparatus and causes a problem of lowering the reliability of the use result.

Therefore, many researches and developments are currently under way to solve such problems. For example, in Korean Patent No. 10-00708307, a temperature monitoring system and method for a power semiconductor device, a method for measuring the temperature of a power semiconductor and outputting the temperature is proposed. However, the developed methods, including these patent applications, offer a solution to solve the problem of heat or noise generated in most power conversion devices, and do not suggest a solution to the problem of heat and noise at the same time.

Korean Patent No. 10-2010-07023012 (Jan. 18, 2010)

SUMMARY OF THE INVENTION A problem to be solved by the present invention is to provide a power converter that operates in a time-shifting manner by using a plurality of converters so as to grasp the number of output stages of the converter by using the ripple of the output current, To a power 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 power conversion apparatus comprising: a rectifying unit for rectifying an alternating current applied by an AC power source; a smoothing unit connected in parallel to the rectifying unit to charge the rectified charge to output a direct current; A first converter unit and a second converter unit connected in parallel to each other for time shift operation so as to form a phase difference of an output voltage to output a combined current, a second converter unit connected to an output terminal of the first converter unit, A second DC link part connected to an output terminal of the second converter part to charge the electric charge outputted from the second converter part, a first DC link part connected to an output terminal of the second converter part, Wherein the second DC link unit includes a second output terminal to which the load is connected, and at least one of the first output terminal and the second output terminal is connected to the first direct current The current control unit may measure the current flowing from the current link unit and the second direct current link unit to the load and compare the ripple of the current with the setting ripple.

Wherein the determination control unit determines that the load is connected to the coupled output terminal to which the first output terminal of the first DC link unit and the second output terminal of the second DC link unit are coupled when the size of the ripple is greater than or equal to the size of the set ripple, And that the load is connected to the first output terminal and the second output terminal when the size of the ripple is less than or equal to the size of the set ripple.

When the magnitude of the combined current output from the first converter unit and the second converter unit is greater than or equal to the rated current of the load, the first converter unit and the second converter unit The first converter unit and the second converter unit operate together when the magnitude of the combined current output from the first converter unit and the second converter unit is equal to or less than the rated current of the load, can do.

Wherein the first converter section and the second converter section form a plurality of semiconductor set sections in which a semiconductor switch and a diode are connected in series, wherein the semiconductor set section of the first converter section and the semiconductor set section of the second converter section alternately operate .

A first DC reactor part may be interposed between the first converter part and the first DC link part and a second DC reactor part may be interposed between the second converter part and the second DC link part.

A first cooling fan that cooperates with the first converter unit to cool the first converter unit and the first DC reactor unit and a second cooling unit that cooperates with the second converter unit to cool the second converter unit and the second DC reactor unit, And a second cooling fan for cooling the part.

The rectifying unit may include a plurality of diode sets connected in series with each other, and the diode sets may be connected in parallel with each other.

In the power conversion apparatus according to the present invention, a plurality of converters for supplying current to the load are operated in a time shift manner, and the number of output stages of the converter can be confirmed by using the ripple of the supplied current. In addition, it is possible to extend the service life of the devices constituting the power conversion apparatus by efficiently operating the converter in response to the number of the identified output terminals and solving the heat generation problem of the converter.

1 is a circuit diagram of a power conversion apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram showing voltage waveforms outputted by the operation of the first converter section and the second converter section of FIG. 1. FIG.
3 is a diagram showing the current waveform measured by the discrimination measurement unit of FIG.
Fig. 4 is a circuit diagram in which a load is connected to the first output terminal and the second output terminal of the power conversion apparatus of Fig. 1, respectively.
5 is a diagram showing voltage waveforms outputted by the operation of the first converter section and the second converter section in FIG.
6 is a diagram showing the current waveform measured by the discrimination measurement unit of FIG.
7 is a circuit diagram in which a load is connected to a coupling output terminal of the power converter of FIG.
8 is a view showing the operation of the first converter unit and the first cooling fan of FIG.
FIG. 9 is a diagram showing a voltage waveform output by the operation of the first converter unit of FIG. 8; FIG.
10 is a view showing the operation of the second converter unit and the second cooling fan of FIG.
11 is a diagram showing a voltage waveform output by the operation of the second converter unit of FIG.
FIG. 12 is a view showing a state in which the first converter unit and the second converter unit of FIG. 7 are operated at the same time.
FIG. 13 is a diagram showing voltage waveforms in which the first converter unit and the second converter unit of FIG. 12 are operated simultaneously and output.

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 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 power conversion apparatus according to an embodiment of the present invention.

Referring to FIG. 1, a power converter 1 according to an embodiment of the present invention operates in an interleaving manner between a first converter unit 41 and a second converter unit 42 that supply current to a load. Therefore, the power conversion apparatus 1 charges the first DC link unit 61 and the second DC link unit 62 according to the operation of the first converter unit 41 and the second converter unit 42. The current supplied to the load from the first DC link unit 61 and the second DC link unit 62 is measured by using the discrimination control unit 80 and the ripple of the current and the setting ripple are compared in size, The first output terminal 71 of the first DC link unit 61 or the second output terminal 72 of the second DC link unit 62 are connected to each other or the first output terminal 71 and the second output terminal 72 are coupled Connected to the coupled output terminal 73 of FIG. When the number of the output terminals identified is a single number, the power converter 1 can control the combined current of the first converter unit 41 and the second converter unit 42 to the first converter unit 41 and the second converter unit 42, The first converter unit 41 and the second converter unit 42 are efficiently operated according to the resultant value by comparing the rated current of the power converter 42 with the rated current of the power converter 42, The problem can be minimized. In this way, the power conversion apparatus 1 not only extends the service life of each component, but also allows the load connected to the power conversion apparatus 1 to be driven smoothly.

Hereinafter, the constituent elements of the power conversion apparatus 1 will be described in more detail.

The power conversion apparatus 1 includes a rectification section 20 for rectifying an AC current, a smoothing section 30 connected in parallel to the rectification section 20, a first converter section 41 connected in parallel to the smoothing section 30, (42) as a component. The power conversion apparatus 1 includes a first DC link unit 61 connected to the output terminal of the first converter unit 41, a second DC link unit 62 connected to the output terminal of the second converter unit 42, And a determination control unit 80 connected to the first output terminal 71 of the first DC link unit 61 and the second output terminal 72 of the second DC link unit 62 to measure a current flowing to the load. In addition, the power conversion apparatus 1 includes DC reactor parts 51 and 52 interposed between each of the converter parts and the DC link parts, a first cooling fan 91 operating together with the first converter part 41, A second cooling fan 92 that operates in conjunction with the second converter unit 42 and a control unit that controls the operation of the first converter unit 41 and the second converter unit 42 can do.

The rectifying unit 20 rectifies the three-phase alternating current applied from the alternating-current power supply 10 to pulsating currents and transmits them to the smoothing unit 30. The rectifying part 20 includes a first diode set part 20a, a second diode set part 20b, a third diode D3, and a third diode D3, which are connected in series with a pair of diodes or a first diode D1 and a second diode D2. And the set portion 20c are connected in parallel to rectify the a-phase ac, the b-phase ac, and the c-phase ac, respectively, and transmit the rectified ripple to the smoothing portion 30. [

The smoothing portion 30 is connected in parallel to the rectifying portion 20 to charge the rectified current in the diode set portions 20a to 20c. In particular, the smoothing unit 30 suppresses voltage fluctuation due to the ripple current supplied from the rectifying unit 20, and applies a DC voltage of a predetermined magnitude to the first converter unit 41 and the second converter unit 42. [

The first converter unit 41 and the second converter unit 42 are connected in parallel to the smoothing unit 30 so as to output a direct current using the voltage applied from the smoothing unit 30, 51 and the second DC link portion 52 can be charged respectively. The first converter unit 41 and the second converter unit 42 may be formed in a structure in which the semiconductor switch T and the semiconductor set connected in series with the diode are connected in parallel to each other. The first converter section 41 is constituted by the first semiconductor set section 41a to the third semiconductor set section 41c and the second converter section 42 is constituted by the fourth semiconductor set section 42a to the sixth semiconductor set section 41c. And a semiconductor set portion 42c, so that the phases of the output voltages can be operated differently. The operation of the first converter section 41 and the second converter section 42 will be described in more detail. After the first semiconductor section 41a of the first converter section 41 is turned on , The fourth semiconductor set part 42a is turned on during the time when the first semiconductor set part 41a is turned off. When the fourth semiconductor set part 42a is turned off and turned off after a predetermined time, the second semiconductor set part 41b is turned off during the time when the fourth semiconductor set part 42a is turned off Turn on. When the second semiconductor set part 41b is turned off, the fifth semiconductor set part 42b is turned on again during that time, and when the fifth semiconductor set part 42b is turned off, The third semiconductor set portion 41 is turned on during a period of time when the first semiconductor set 41 is turned off.

In this way, the first converter section 41 and the second converter section 42 are connected to the second converter section 42 in a cycle formed by the semiconductor set sections 41a to 41c of the first converter section 41, The periodicity formed by the semiconductor set portions 42a to 42c of the semiconductor device is activated to form a voltage waveform that can be interleaved. Here, the semiconductor switch T of the first converter section 41 and the second converter section 42 may be any one of IGBT, IEGT, MOSFET, ICGT, GCT, SGCT and GTO. However, in this specification, an IGBT which is simple to drive and has high efficiency at high voltage and large current is shown as an example of a semiconductor switch. The IGBT has a gate, an emitter and a collector terminal. The gate terminal is provided with a controller (not shown), and the current is outputted while the IGBT is switched on or off via the controller, To be applied to the reactor section 51 and the second DC reactor section 52.

The first DC reactor part 51 is formed in a structure in which a resistor and an inductor are connected in series and can be interposed between the first converter part 41 and the first DC link part 61. Also, the second DC reactor part 61 may be formed in a structure in which a resistor and an inductor are connected in series, and may be interposed between the second converter part 42 and the second DC link part 62.

Therefore, the first DC reactor unit 51 and the second DC reactor unit 52 can control the DC current outputted through the operation of the first converter unit 41 and the second converter unit 42, The waveform can be output. Further, the voltages output from the first DC reactor unit 51 and the second DC reactor unit 52 are applied to the first DC link unit 61 and the second DC link unit 62, respectively, (61) and the second direct current link portion (62).

The first DC link portion 61 is formed of a capacitor having a polarity capable of charging the electric charge, and includes a first output terminal 71 capable of supplying charged electric charge to the load. The second direct current link portion 62 is formed of a capacitor having the same electrical characteristic as the first direct current link portion 61 and includes a second output terminal 72 capable of supplying the charged electric charge to the load.

The first output terminal 71 and the second output terminal 72 may be coupled to one output terminal in accordance with the number of loads and may be formed as a coupled output terminal 73 (see FIG. 7). The first output terminal 71 and the second output terminal 72 may be connected to a discrimination controller 80 for measuring a current flowing to the load at the first DC link part 61 and the second DC link part 62 .

The determination control unit 80 is connected to the controller to compare the ripple of the measured current with the set ripple to determine the number of output stages connected to the load, and to determine the number of output stages connected to the first converter unit 41 and the second converter unit 2 converter section 42 can be operated efficiently. For example, when the magnitude of the ripple of the measured current is equal to or smaller than the setting ripple magnitude, the load is applied to the first output terminal 71 of the first DC link unit 61 and the second DC link unit 62, respectively. When the load is larger than the first output terminal 71 of the first direct current link section 61 and the second direct current link section 62 of the first direct current link section 61 when the magnitude of the ripple of the current measured by the discrimination control section 80 is equal to or larger than the set ripple magnitude, The second output terminal 72 is connected to the coupled output terminal 73 to which the second output terminal 72 is connected.

When the load is connected to a single output terminal, that is, to the coupling output terminal 73, the first converter section 41 and the second converter section 42 operate either one at a predetermined time interval corresponding to the amount of current supplied to the load So that the first converter section 41 and the second converter section 42 are operated together. The first cooling fan 91 can be operated together with the first converter unit 41 and the second cooling fan 92 can be operated together with the second converter unit 42. [ The first cooling fan 91 is disposed adjacent to the first converter unit 41 and the first DC reactor unit 51 and the second cooling fan 92 is disposed adjacent to the second converter unit 41 and the first DC reactor unit 51. In this case, Two DC reactor portions 52 so that the heat generated while the converter portions 41 and 42 and the DC reactor portions 51 and 52 are operated can be discharged to the outside.

Hereinafter, the case where the magnitude of the ripple of the current measured by the determination control unit 80 is equal to or smaller than the size of the set ripple will be described with reference to FIG. 2 to FIG.

FIG. 2 is a view showing a voltage waveform output by the operation of the first converter section and the second converter section of FIG. 1, FIG. 3 is a diagram showing a current waveform measured by the discrimination measurement section of FIG. 2, 1 is connected to a first output terminal and a second output terminal of the power conversion apparatus.

2 (a) shows the voltage waveform measured by the first DC reactor part 51 when the first converter part 41 is activated, and FIG. 2 (b) And becomes the voltage waveform measured by the second DC reactor unit 52. The voltages outputted from the first DC reactor part 51 and the second DC reactor part 52 by the operation of the first converter part 41 and the second converter part 42 are formed into a phase that can be interleaved with each other And output.

When a low current (for example, 0 to 10 A) of the current output from the first DC link unit 51 and the second DC link unit 52 is measured, as shown in FIG. 3, It can be inferred that a load is connected to each output terminal and a circulating current is not formed at the output terminal when the output P is measured below the set ripple SP. In other words, when the ripple P of the current is measured to be equal to or lower than the set ripple SP, the determination control unit 80 determines that the load is connected to the first output terminal 71 and the second output terminal 72 .

Hereinafter, the case where the magnitude of the ripple of the current measured by the determination control unit 80 is equal to or larger than the magnitude of the setting ripple will be described with reference to FIGS. 5 to 7. FIG.

FIG. 5 is a diagram showing a voltage waveform output by the operation of the first converter unit and the second converter unit of FIG. 1, FIG. 6 is a diagram showing a current waveform measured by the discrimination unit of FIG. 5, 1 is connected to the output of the power converter.

5, the first converter unit 41 and the second converter unit 42 are arranged such that the voltages output from the first converter unit 41 and the second converter unit 42 are interleaved with each other, . When the low current of the current outputted from the first DC link unit 51 and the second DC link unit 52 is measured, the ripple P of the current is set to the set ripple SP ), It can be deduced that the circulating current is formed at the output terminal to which the load is connected. 7, when the ripple P of the current is measured to be equal to or greater than the set ripple SP, the determination control unit 80 determines that the first output terminal 71 and the second output terminal 72 are coupled to each other, It can be determined that the load is connected to the output terminal 73.

Hereinafter, with reference to FIGS. 8 to 13, a state in which the load is operated according to the magnitude of the current supplied to the load when the load is connected to the coupled output terminal will be described in detail.

First, when the rated current of the load is equal to or lower than the combined current output from the first converter section 41 and the second converter section 42, the first converter section 41 and the second converter section 42 are time- Only one of them can work. For example, when the maximum synthesized current output from the first converter section 41 becomes 105 A in a situation where a current must be supplied to a load having a rated current of 105 A, the load becomes a composite output from the first converter section 41 It can be operated by an electric current. At this time, the semiconductor set portions 41a to 41c of the first converter unit 41 can be operated to output the voltage as shown in FIG. 9, and the first cooling fan 41 and the second cooling fan 41, together with the first converter unit 41, (91) can be operated. The first cooling fan 91 discharges the heat generated from the first converter unit 41 and the first DC reactor unit 51 to the outside and supplies the heat to the first converter unit 41 and the first DC reactor unit 51, To be cooled smoothly. 10, the first converter section 41 and the first cooling fan 91 are stopped (OFF), and the second converter section 42 and the second cooling section The fan 92 can be turned ON. At this time, the second converter unit 42 also outputs a synthesized current corresponding to the rated current of the load, so that the load can be smoothly operated. Furthermore, the semiconductor set portions 42a to 42c of the second converter portion 42 are operated at different times to be switched to the semiconductor set portions 41a to 42c of the first converter portion 41, respectively. That is, as shown in FIG. 11, the second converter unit 42 converts the three-phase voltage output from the second converter unit 42 into a three-phase voltage output from the first converter unit 41, The switching time is shifted and operated.

On the other hand, when the rated current of the load is equal to or greater than the combined current output from the first converter section 41 and the second converter section 42, the first converter section 41 and the second converter section 42 operate simultaneously The semiconductor set portions 41a to 41c of the first converter portion 41 and the semiconductor set portions 42a to 42c of the second converter portion 42 can operate simultaneously.

For example, when the maximum combined current in the first converter section 41 is 105 A in a situation where a current must be supplied to a load having a rated current of 106 A, the first semiconductor section 41a of the first converter section 41 ) To the third semiconductor set section 41c are operated and the first converter section 41 outputs 53A. Then, the fourth semiconductor set 42a to the sixth semiconductor set 42c of the second converter 42 operate, and the second converter 42 outputs 53A. Thus, the currents output from the respective converter units 41 and 42 are combined to supply a current of 106 A to the load. At this time, the voltages outputted by the semiconductor switches T of the first converter section 41 and the second converter section 42 are outputted at the same time so that they can be synthesized. That is, as shown in FIG. 13, the first converter section 41 and the second converter section 42 operate so that the phases of the output three-phase voltages are the same.

When the rated current of the load is equal to or greater than the current that can be output from the first converter section 41, the first converter section 41 and the second converter section 42 operate, And the second cooling fan 92 operate to smoothly cool the first converter section 41 and the second converter section 42 as well as the first DC reactor section 51 and the second DC reactor section 52 .

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: Power converter 10: AC power source
20: rectification part 20a: first diode set part
20b: second diode set part 20c: third diode set part
30: Smooth part
41: first converter section 41a: first semiconductor set section
41b: second semiconductor set part 41c: third semiconductor set part
42: second converter section 41a: fourth semiconductor set section
41b: fifth semiconductor set part 41c: sixth semiconductor set part
51: first DC reactor part 52: first DC reactor part
61: first DC link part 62: second DC link part
71: first output terminal 72: second output terminal
80:

Claims

A rectifying unit for rectifying the AC current applied by the AC power source;
A smoothing unit connected in parallel to the rectifying unit to charge the rectified charge and output the rectified current as a direct current;
A first converter unit and a second converter unit connected in parallel to the smoothing unit to output a synthesized current by time shift operation so that a phase difference of an output voltage is formed;
A first DC link part connected to an output terminal of the first converter part and charging the electric charge outputted from the first converter part;
A second DC link part connected to an output terminal of the second converter part and charging the electric charge outputted from the second converter part; And
Wherein the first DC link unit includes a first output terminal to which a load is connected, and the second DC link unit includes a second output terminal to which the load is connected, and at least one of the first output terminal and the second output terminal A determination control unit for measuring the current flowing from the first DC link unit and the second DC link unit to the load and comparing the ripple of the current with the set ripple,
Wherein the determination control unit determines that the load is connected to the coupled output terminal to which the first output terminal of the first DC link unit and the second output terminal of the second DC link unit are coupled when the size of the ripple is greater than or equal to the size of the set ripple, And determines that the load is connected to the first output terminal and the second output terminal when the size of the ripple is less than or equal to the size of the set ripple,
When the magnitude of the combined current output from the first converter unit and the second converter unit is greater than or equal to the rated current of the load, the first converter unit and the second converter unit The first converter unit and the second converter unit operate together when the magnitude of the combined current output from the first converter unit and the second converter unit is equal to or less than the rated current of the load, and,
Wherein a first DC reactor part is interposed between the first converter part and the first DC link part and a second DC reactor part is interposed between the second converter part and the second DC link part,
A first cooling fan that cooperates with the first converter unit to cool the first converter unit and the first DC reactor unit and a second cooling fan that cooperates with the second converter unit to cool the second converter unit and the second DC reactor unit, And a second cooling fan for cooling the reactor section.

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The semiconductor device according to claim 1, wherein the first converter unit and the second converter unit form a plurality of semiconductor set units connected in series with a semiconductor switch and a diode, wherein the semiconductor set unit of the first converter unit and the semiconductor And the set portion operates alternately.

delete

The power conversion apparatus according to claim 1, wherein the rectifying unit includes a plurality of diode sets connected in series, the diode sets being connected in parallel with each other.