KR20150066380A - Single-stage AC/DC Converter using Integrated CM/DM Choke - Google Patents

Abstract

The present invention relates to a single-stage AC/DC converter using an integrated CM/DM choke capable of removing an existing inductor and diode, using an integrated CM/DM choke to reduce the number of elements, and improving power factor. The present invention includes a power part which applies AC input power (V1); a resonance circuit part which is connected to the power part and improves power factor; a bridge diode part which is connected to the power part and provides a current path; an integrated CM/DM choke part which removes conduction noise according to current flow from the power part; a bulk capacitor which stores a DC voltage smoothed through the bridge diode part by corresponding to the AC voltage of the power part; a transformer circuit part which transmits DC voltage stored in the bulk capacitor to a secondary side and outputs the voltage to the secondary side; and a switching device which is connected to the bulk capacitor and the transformer circuit part and performs switching to apply DC voltage stored in the bulk capacitor to the transformer circuit part.

Description

{Single-stage AC / DC converter using integrated CM / DM choke}

The present invention relates to a single-stage AC / DC converter, in particular, an AC / DC converter that eliminates a conventional inductor and a diode and reduces the number of elements by applying an integrated CM / DM choke, stage AC / DC converter using an integrated type C / D choke for improving the power factor in the form of a single stage AC / DC converter.

Switch Mode Power Supply (SMPS) uses a capacitor input type rectifier with a full-wave rectifier and a smoothing capacitor at the input. This can cause voltage distortion and have a serious effect on the power system. Therefore, international organizations such as IEC and IEEE have established harmonic current standards and regulated harmonic currents.

Therefore, the need for power factor correction (PFC) circuitry is increasing, and one of the most widely used methods is the two-stage power factor correction scheme. The two-stage power factor improvement method consisting of the PFC stage and the DC / DC converter stage requires a separate controller and switch at each stage, which complicates the circuit and increases the number of elements, resulting in a high manufacturing cost.

To overcome the drawbacks of the prior art, a single-stage power factor correction scheme combining a PFC stage and a DC / DC converter stage is used. However, in the single-stage power factor correction method, the voltage of the bulk capacitor is increased in the continuous conduction mode, and the current and voltage stress of the switch are increased. This can be overcome by a single-stage charge pump power factor correction scheme.

1 is a circuit diagram of a conventional single-stage charge pump power factor improving converter. 1, the conventional converter includes one resonant circuit (Lr, Cr, Cs), two diodes (Dx, Ds), and one bulk capacitor (Cb). These converters do not continuously increase the bulk capacitor voltage during small loads. In addition, the switch voltage stress can be clamped and the power factor improvement is high. However, there is a problem that the circuit is complicated and expensive because of a large number of elements.

Japanese Patent Application Laid-Open No. 10-2013-0076925 Patent Registration No. 0420964 Published Utility Model No. 20-2013-0006019

SUMMARY OF THE INVENTION The present invention has been proposed in order to solve the problems of the prior art, and it is an object of the present invention to eliminate the inductor and the two diodes in the conventional single stage charge pump power factor improving converter and apply the integrated C / D choke One-stage AC / DC converter using an integrated S / M choke for reducing the number of power supplies and maintaining a power factor improving function.

A single-stage AC / DC converter using an integrated S / M choke according to the present invention includes:

A power supply unit for applying an AC input power Vi; A resonance circuit part connected to the power supply part 10 for improving the power factor; A bridge diode connected to the power supply unit to provide a current path; A bulk capacitor (Cb) for storing a smoothed direct current voltage through the bridge diode; A transformer circuit part for transmitting a DC voltage provided from the bulk capacitor (Cb) to a secondary side and outputting a voltage to the secondary side; And a switching device (Q) connecting the bulk capacitor (Cb) and the transformer circuit part to switch a DC voltage stored in the bulk capacitor (Cb) to be applied to the transformer circuit part; And the inductor Lr1 and the two capacitors Cr and Cs are connected in series to the inductor Lr1 and the two capacitors Cr and Cs for eliminating conduction noise of the power line. Are respectively connected in series to the power source unit.

In the present invention, the bridge diode unit is configured with four diodes connected in a full bridge manner.

The voltage stored in the inductor Lr1 and the two capacitors Cr and Cs is stored and the voltage stored in the two capacitors Cr and Cs is clamped to be constant The voltage stored in the inductor Lr1 is transferred to the bulk capacitor Cb.

The voltage stored in the two capacitors Cr and Cs is transmitted to the transformer circuit unit 140 and is divided into two according to the turns ratio n of the transformer T. In this case, And the DC voltage Vo is outputted to the vehicle side.

In the present invention, when the voltage of the two capacitors Cr and Cs is clamped to -nVo (where n is the winding ratio of the transformer), the voltage stress of the switching device Q is clamped to Vin + nVo.

According to the present invention, compared with the conventional single-stage charge pump converter circuit, improvement in power factor is ensured, but the number of elements to be applied is small, so that miniaturization is possible, manufacturing is simplified, and manufacturing cost is reduced.

1 is a circuit diagram of a conventional single-stage charge pump power factor improving converter.
2 is a circuit diagram of a single-stage AC / DC converter using an integrated S / M choke according to the present invention.
3 is a simulation circuit diagram of a single-stage AC / DC converter using an integrated S / M choke according to an embodiment of the present invention.
4 is a waveform diagram of a voltage according to a result of simulation in Fig.
Fig. 5 is a waveform diagram of current according to the result of the simulation of Fig. 3; Fig.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

2 is a circuit diagram of a single-stage AC / DC converter using an integrated S / M choke according to the present invention.

Referring to FIG. 2, a single-ended AC / DC converter 100 using an integrated S / M choke according to the present invention includes a power supply unit 110, a resonant circuit unit 120, a bridge diode unit 130, a bulk capacitor Cb, A switching element Q, and a transformer circuit portion 140. As shown in Fig. This configuration is a state in which two diodes Dx and Ds and an inductor Lr of the conventional resonance circuit unit 120 are removed in comparison with the conventional single-stage charge pump power factor improving converter shown in Fig. 1, CM / DM chokes are used. For example, in Fig. 2, the inductor formed by this integrated CM / DM choke is represented by Lr1.

In the integrated CM / DM choke 140 of the present embodiment, the conduction noise of each power supply line in the continuous conduction mode is determined by noise due to a common mode (CM) current component and a noise due to a differential mode (DM) The common choke and the DM choke are the coils used for the filter for eliminating the common mode (CM) noise and the differential mode (DM) noise, respectively. In the present invention, the inductor Lr and the two diodes Dx and Ds in the conventional converter circuit can be removed by integrating and implementing such CM choke and DM choke.

The power supply unit 110 applies the AC voltage Vi. The current is supplied to the resonance circuit portions (Lr1, Cr, Cs) 120 by the applied voltage Vi. As described above, the resonance circuit unit 120 includes the integrated CM / DM choke. Specifically, the inductor Lr1 includes an integrated CM / DM choke. The bridge diode unit 130 includes four diodes D1 to D4 connected in the form of a full bridge to provide a current path and transfer the electric energy to be passed to the bulk capacitor Cb. Thus, the bulk capacitor Cb stores electric energy transmitted through the bridge diode unit 130.

The output voltage of the AC / DC converter 100 is adjusted by the duty ratio of the switching element Q. Also, the switching element Q performs a single-ended voltage control function for controlling the output voltage and simultaneously improving the power factor of the input terminal. The switching device Q is configured to be applicable to a flyback type, a forward type, and a half bridge type converter together with the transformer circuit portion 140. In the present embodiment, the on / off operation of the switching element Q is controlled by a control unit (not shown).

The operation of the single stage AC / DC converter 100 using the integrated S / M choke according to the present invention constructed as above will be described with reference to FIG.

First, when the switching element Q is turned on, electric energy is stored in the resonance circuit sections Lr1, Cr, and Cs 120. When the voltages of the capacitors Cr and Cs of the resonance circuit section 120 are clamped and become constant, The current does not flow to the further switch, and the energy stored in the inductor Lr1 of the resonant circuit part 120 is transferred to the bulk capacitor Cb.

Thereafter, when the switching element Q is turned off, the energy stored in the capacitors Cr and Cs of the resonance circuit portion 20 is transmitted to the transformer circuit portion 140. A voltage is induced on the secondary side according to the winding ratio (n: 1) of the transformer T, so that the output diode Do of the secondary side is conducted and the DC voltage is charged to the output capacitor Co. Thereafter, the voltage of the capacitors Cr and Cs of the resonant circuit portion 20 is clamped to -nVo (here, the turns ratio of the transformer). Therefore, the voltage stress of the switching device Q is clamped to Vin + nVo, so that the voltage stress of the switching device Q can be reduced as compared with the conventional circuit.

Subsequently, when the current of the primary side of the transformer T becomes 0 (zero), the output diode Do of the secondary side is turned off and all operations are ended.

As described above, in the single-stage AC / DC converter 100 using the integrated S / M choke according to the present invention, the same operation as that of the conventional single-stage charge pump power factor improving converter is performed to ensure improvement of the power factor, It is more advantageous in terms of cost. In addition, since the number of such devices is reduced, it is possible to downsize and has an advantage that it is simple to manufacture.

[Experimental Example]

3 is a simulation circuit diagram of a single stage AC / DC converter using an integrated S / M choke according to an embodiment of the present invention.

3, in the simulation circuit diagram of the single-stage AC / DC converter 100 according to the present invention, the input AC voltage Vi is implemented at 325 V / 50 Hz and the Lr1, Cr, Cs are implemented as 5mH, 5μ, and 5μ, respectively. Simulation experiments were carried out after implementing both the bulk capacitor (Cb) and the output capacitor (Co) on the secondary side with 20μ and the resistance on the secondary side with 400Ω. The results of these simulations are shown in FIG. 4 and FIG.

FIG. 4 is a waveform diagram of a voltage according to a result of the simulation of FIG. 3, and FIG. 5 is a waveform diagram of a current according to a simulation result of FIG. 4 and 5, the AC input voltage Vi is in the form of a sine wave, the bulk capacitor Cb is charged with a DC voltage of about 400 V, and the output voltage of the secondary side of the transformer is a DC voltage of about 150 V . Particularly, since the bulk capacitor is charged with a constant DC voltage of 400 V, the voltage of the bulk capacitor is continuously increased in the conventional single-stage charge pump power factor improving converter.

Although the present invention has been described in detail with reference to preferred embodiments thereof, it is to be understood that the invention is not limited to the details of the illustrated embodiments. Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope of the appended claims, The genius will be so self-evident. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

110: power supply unit 120: resonance circuit unit
130: bridge diode section 140: transformer circuit section
Cb: Bulk capacitor Q: Switching element

Claims (5)

A power supply unit 110 for applying an AC input voltage Vi;
A resonance circuit part 120 connected to the power supply part 10 for improving the power factor;
A bridge diode unit 130 connected to the power supply unit 10 and providing a current path;
A bulk capacitor Cb for storing a smoothed direct current voltage through the bridge diode unit 130;
A transformer circuit unit 140 for transmitting a DC voltage provided from the bulk capacitor Cb to a secondary side and outputting a voltage to the secondary side; And
A switching element Q connecting the bulk capacitor Cb and the transformer circuit part 150 to switch a DC voltage stored in the bulk capacitor Cb to be applied to the transformer circuit part 150; Lt; / RTI >
The resonant circuit unit 120 includes an integrated CM / DM choke inductor Lr1 and two capacitors Cr and Cs for eliminating the conduction noise of the power supply line. The inductor Lr1 and the two capacitors Cr and Cs are connected in series, Is a single-ended AC / DC converter using an integrated S / M choke connected in series to the power supply unit (110). The method according to claim 1,
Wherein the bridge diode unit includes four diodes connected in the form of a full bridge, and a single-ended AC / DC converter using the integrated S / M choke. The method according to claim 1,
When a voltage is stored in the inductor Lr1 and two capacitors Cr and Cs and the voltage stored in the two capacitors Cr and Cs is clamped and becomes constant when the switching device Q is turned on, And the voltage stored in the capacitor (Lr1) is transferred to the bulk capacitor (Cb). The single-ended AC / DC converter uses the integrated S / M choke. The method of claim 3,
When the switching device Q is turned off, the voltages stored in the two capacitors Cr and Cs are transferred to the transformer circuit part 140 and are supplied to the secondary side in accordance with the winding ratio (n: 1) Single-ended ac / dc converter using integrated S / M choke with voltage Vo output. 5. The method of claim 4,
When the voltage of the two capacitors Cr and Cs is clamped to -nVo (where n is the winding ratio of the transformer), the voltage stress of the switching device Q is clamped to Vin + nVo. Once AC / DC converters.

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