KR20100023305A - Device for converting dc/dc - Google Patents

Abstract

PURPOSE: A device for converting dc/dc is provided to reduce power loss effectively by soft-switching all switching elements. CONSTITUTION: A DC / DC converter comprises an input inductor(L), a first switching element(100), a resonant unit(400), a second switching element(200), a first diode(D10), a second diode(D20), a third switching element(200), and a smoothing capacitor(Co). The first switching element comprises a first switching element(S1) and a first backward diode(D1). The first switching element is connected to the input inductor. The resonant unit comprises a resonant inductor and the resonance capacitor. The second switching element comprises a second switching element(S2) and the second backward diode(D2). The second switching element is connected to the resonant inductor. The first diode is connected between the first switching element and the second switching element. The second diode is connected between the input inductor and the resonant inductor. The third switching element comprises a third switching element(S3) and the third backward diode(D3). The smoothing capacitor is connected to the third switching element.

Description

DC / DC converters {DEVICE FOR CONVERTING DC / DC}

The present invention relates to a DC / DC converter.

In general, the DC / DC converter adjusts the level of the DC voltage, and a representative DC / DC converter includes a booster converter.

The booster converter accepts a small DC voltage and boosts it to a higher voltage level to provide the output voltage.

Such booster converters are used in power conditioning systems (PCS) of solar power generation.

However, the above-mentioned booster converter includes a switching element, and there is a problem that power loss occurs during turn-on and turn-off of the switching element, and electromagnetic interference (EMI) noise is caused.

The DC / DC converter according to the embodiment of the present invention can effectively reduce power loss and electromagnetic interference (EMI) noise.

Technical problems to be achieved by the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned above are provided to those skilled in the art (hereinafter, those skilled in the art) from the following description. It will be clearly understood.

A DC / DC converter according to an embodiment of the present invention includes a first switching device including an input inductor, a first switching device connected to the input inductor, and a first reverse diode connected in parallel to the first switching device in reverse direction. A resonator including a resonant inductor connected to the first switching element, a resonant capacitor connected to the input inductor, a second switching element connected to the resonant inductor, and a parallel connection in a reverse direction to the second switching element. A second switching unit including a second reverse diode, a first diode connected to the first switching element and the second switching element, a second diode connected between the input inductor and the resonance inductor, and the resonance capacitor A third switching element connected thereto and a third reverse diode connected in parallel to the third switching element in a reverse direction; And a smoothing capacitor connected to the third switching device and the third switching device.

According to the embodiments of the present invention, since all switching elements are soft switched, power loss and electromagnetic interference (EMI) noise may be effectively reduced.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Specific details of other embodiments are included in the detailed description and the drawings. Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. Like reference numerals refer to like elements throughout.

1 is a circuit diagram of a DC / DC converter according to a first embodiment of the present invention, FIG. 2 is a circuit diagram of a DC / DC converter according to a second embodiment of the present invention, and FIG. 3 is FIGS. 1 and 2. 4 is a signal waveform diagram of the circuit diagram of FIG. 3, and FIGS. 5A to 5F are circuit diagrams showing the flow of current for each operation mode.

In the DC / DC converter according to the first embodiment of the present invention, the input inductor L, the resonator 400, the first switching unit 100, and the first diode D10 are illustrated in FIG. 1. , A second diode D20, a second switching unit 200, a third switching unit, and a smoothing capacitor Co.

An input voltage Vin is applied to the input inductor L, and the first switching unit 100 reverses the first switching element S1 connected to the input inductor L and the first switching element S1. It includes a first reverse diode (D1) connected in parallel.

Here, the first switching element S1 may be configured as an Insulated Gate Bipolar Transistor (IGBT) or a metal oxide semiconductor field effect transistor (MOS FET), and the first reverse diode D1 may be a first switching element. When (S1) is an IGBT, a separate diode is connected in parallel to the first switching element S1 in a reverse direction as shown in FIG. 1, and when the first switching element S1 is a MOS transistor, a body parasitic to the MOS transistor. Diodes can be used.

The resonator 400 includes a resonant inductor Lr connected to the first switching element and a resonant capacitor Cr connected to the input inductor L.

In addition, the second switching unit 200 includes a second switching element S2 connected to the resonant inductor Lr, and a second reverse diode D2 connected in parallel to the second switching element S2 in reverse direction. .

Here, the second switching element S2 may be composed of an Insulated Gate Bipolar Transistor (IGBT) or a Metal Oxide Semiconductor Field Effect Transistor (MOS FET), and the second reverse diode D2 is the second switching element. When (S2) is an IGBT, a separate diode is connected in parallel to the second switching element (S2) in a reverse direction as shown in FIG. Diodes can be used.

Meanwhile, the first diode D10 is connected between the first switching element and the second switching element S2, and the second diode D20 is connected between the input inductor L and the resonant inductor Lr.

In addition, the third switching unit 300 includes a third switching element S3 connected to the resonant capacitor Cr, and a third reverse diode D3 connected in parallel to the third switching element S3 in a reverse direction. , The smoothing capacitor Co is connected to the third switching element S3.

Here, the third switching device S3 may be configured as an Insulated Gate Bipolar Transistor (IGBT) or a metal oxide semiconductor field effect transistor (MOS FET), and the third reverse diode D3 may be a third switching device. When S3 is IGBT, a separate diode is connected in parallel to the third switching element S3 in a reverse direction as shown in FIG. 1, and when the third switching element S3 is a MOS transistor, a body parasitic to the MOS transistor Diodes can be used.

The first embodiment includes a single phase inverter 1100 including inverter switching elements S11, S12, S13, S14 and reverse diodes D11, D12, D13, D14, an inductor LF, and a capacitor CF. The output filter 1200 is connected.

The second embodiment will be described with respect to the difference from the first embodiment.

The second embodiment includes a three-phase inverter 2100 including inverter switching elements S21, S22, S23, S24, S25, and S26, reverse diodes D21, D22, D23, D24, D25, and D26, and an inductor. An output filter 2200 including La, Lb, Lc and capacitors Ca, Cb, Cc is connected.

As shown in FIG. 3, the first embodiment and the second embodiment may be equivalent to include an inverter switching element Sinv, a reverse diode Dinv, and a current source Io.

Specific operations will be described with reference to FIGS. 4 and 5A to 5F.

In mode 1, the first switching element S1 and the second switching element S2 are turned on, a current path as shown in FIG. 5A is formed, and the current iLr of the resonant inductor Lr increases linearly. do.

In mode 2, the current iL of the resonant inductor Lr and the current iLr of the input inductor L are equal, and a current path as shown in FIG. 5B is formed, and the resonant inductor Lr and the resonant capacitor ( Cr resonates so that the voltage Vcr of the resonant capacitor Cr is reduced to zero at the output voltage Vo.

In mode 3, the current iL of the input inductor L linearly rises, a current path as shown in FIG. 5C is formed, and the current iLr of the resonant inductor Lr is the first diode D10. And reflux through the second diode D20. The first switching element S1 and the second switching element S2 are turned on under a zero voltage condition. In addition, the inverter switching element Sinv may also perform zero voltage switching.

In mode 4, the first switching element S1 and the second switching element S2 are turned off, a current path as shown in FIG. 5D is formed, and the resonant inductor Lr and the resonant capacitor Cr resonate. . The voltage Vcr of the resonant capacitor Cr rises.

In mode 5, a current path as shown in FIG. 5E is formed, the voltage Vcr of the resonant capacitor Cr is equal to the output voltage Vo, and the resonant inductor Lr through the third reverse diode D3. Current iLr decreases linearly.

In mode 0, a current path as shown in FIG. 5F is formed, energy is transferred to the load, and the current iLr of the resonant inductor Lr becomes zero.

While the invention has been described and illustrated in connection with a preferred embodiment for illustrating the principles of the invention, the invention is not limited to the configuration and operation as such is shown and described.

Rather, it will be apparent to those skilled in the art that many changes and modifications to the present invention are possible without departing from the spirit and scope of the appended claims.

Accordingly, all such suitable changes and modifications and equivalents should be considered to be within the scope of the present invention.

1 is a circuit diagram of a DC / DC converter according to a first embodiment of the present invention.

2 is a circuit diagram of a DC / DC converter according to a second embodiment of the present invention.

3 is a common equivalent circuit diagram of FIGS. 1 and 2.

4 is a signal waveform diagram of the circuit diagram of FIG.

5A-5F are circuit diagrams showing the flow of current for each mode of operation.

<Description of Signs of Major Parts of Drawings>

100: first switching unit

200: second switching unit

300: the third switching unit

400: resonator

Claims (10)

Input inductor; A first switching unit including a first switching element connected to the input inductor and a first reverse diode connected in parallel to the first switching element in parallel; A resonator including a resonant inductor connected to the first switching element and a resonant capacitor connected to the input inductor; A second switching unit including a second switching element connected to the resonant inductor, and a second reverse diode connected in parallel to the second switching element in parallel; A first diode connected between the first switching element and the second switching element; A second diode coupled between the input inductor and the resonant inductor; A third switching unit including a third switching element connected to the resonant capacitor and a third reverse diode connected in parallel to the third switching element in parallel; And DC / DC converter comprising a smoothing capacitor connected to the third switching element. The method of claim 1, The first switching element is an Insulated Gate Bipolar Transistor (IGBT). The method of claim 1,  The first switching device is a metal oxide semiconductor field effect transistor (MOS FET) DC / DC converter. The method of claim 3, And the first reverse diode is a body diode parasitic in the MOS transistor. The method of claim 1, The second switching device is an Insulated Gate Bipolar Transistor (IGBT). The method of claim 1,  The second switching device is a metal oxide semiconductor field effect transistor (MOS FET) DC / DC converter. The method of claim 6, And the second reverse diode is a body diode parasitic to the MOS transistor. The method of claim 1, The third switching device is an Insulated Gate Bipolar Transistor (IGBT). The method of claim 1,  The third switching device is a metal oxide semiconductor field effect transistor (MOS FET) DC / DC converter. The method of claim 9, And the third reverse diode is a body diode parasitic in the MOS transistor.

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