KR101483989B1 - Switching mode power supply having power factor correction circuit and mobile communication repeater system using the same - Google Patents

Abstract

The present invention relates to a switching mode power supply apparatus to which a power factor correction circuit is applied and a mobile communication repeater system using the same. More particularly, the present invention relates to a power supply system (SMPS) to which a power factor correction (PFC) By reducing the apparent power by applying it, energy saving can be achieved. Accordingly, by incorporating a power factor correction circuit in the power supply unit, the input power waveform distortion due to the power factor correction can be minimized to reduce the reactive power of the load, thereby ensuring a high power factor in a wide output range. The power factor variation can be minimized. Also, by providing an EMI filter technology that can guarantee a high power factor over a wide output range in order to minimize the input current waveform distortion generated by the capacitor, it is possible to reduce noise and AC input signals output from the power supply device employing the power factor correction circuit EMI can be reduced.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching power supply apparatus and a mobile communication repeater system using the power factor correction circuit,

The present invention relates to a power supply apparatus, and more particularly, to a power supply system (SMPS) to which a power factor correction (PFC) is applied to a mobile communication repeater system to reduce apparent power, And a mobile communication repeater system using the same.

A mobile communication system refers to a communication system that enables a user to communicate regardless of a location by transmitting and receiving voice or data through a wireless signal with a user terminal. Such a mobile communication system performs wireless communication with a terminal through a base station disposed in a plurality of areas, and uses a repeater to enable communication in a wider area than a coverage area of a shadow area or a base station.

The repeater of the mobile communication system is connected to the base station through a radio or optical line, amplifies the downlink signal transmitted from the base station, and transmits the amplified downlink signal to the terminal located in the coverage area of the mobile communication system. To the base station.

In general, a power supply device applied to a repeater is an expensive device connected to an electronic device to supply stable power and to continuously supply the power even in an emergency so as to drive the electronic device without interruption. In addition, the power factor compensation circuit reduces the reactive power among the power consumed by the load of the specific equipment, thereby improving the quality of the power and preventing the harmonic distortion. Therefore, it is possible to prevent deterioration of various power devices, Can be extended. Therefore, from a national point of view, it is recommended in terms of lowering the apparent power, reducing electricity costs, minimizing energy loss, and reducing greenhouse gas emissions.

However, in the conventional mobile communication repeater system, a power supply having a low power factor is used to shorten the lifespan of a load, and the ratio of the reactive power to the active power is excessively high, . Also, in order to increase the power efficiency, the power supply with the power factor compensation circuit needs more time and effort to emit more noise and remove it, and a large-capacity noise canceling filter is needed.

Such a large-capacity filter uses a large-sized capacitor component, which can improve the EMI prevention characteristic. However, since the capacitance of the capacitor is large, the output of the power supply device may change, The distortion of the power factor is degraded, which causes the power factor to decrease and fluctuate.

That is, since the power factor deteriorates due to a change in the output of the power supply unit 33, a more effective countermeasure for preventing electromagnetic interference is established and the power factor of the wide power supply unit 33 can be maintained There is a need for a method that can expect high power efficiency.

Korean Registered Patent No. 10-0685722, registered on February 15, 2007 (Name: Power Factor Correction Circuit)

It is an object of the present invention to solve the above-mentioned problems, and an object of the present invention is to provide a power factor correction circuit which can reduce harmonics distortion and improve power factor by applying a power factor compensation circuit to a power supply device of a mobile communication repeater system, Circuit, and a mobile communication repeater system using the same.

It is another object of the present invention to provide a switching mode power supply device with a power factor correction circuit capable of eliminating electromagnetic interference (EMI) output from a power supply device using a power factor compensation circuit and an AC input terminal And a mobile communication repeater system using the same.

There is provided a mobile communication repeater using a switching mode power supply apparatus to which a power factor correction circuit (PFC) adapted to transmit a signal transmitted from a base station to a terminal or a base station according to an embodiment of the present invention is applied A downlink signal processor for receiving a downlink signal transmitted from the base station and transmitting the downlink signal to at least one terminal, a downlink signal processor for receiving an uplink signal transmitted from the terminal and transmitting the downlink signal to the base station, and a power supply for a mobile communication relay service And at least one power factor compensating circuit for supplying the at least one power factor compensating circuit.

In addition, in the mobile communication repeater using the switching mode power supply device according to the present invention, the power supply device includes a plurality of normal mode filters, and the normal mode noise of the DC power source, which is output from the common mode filter of the line filter, Is removed.

Also, in the mobile communication repeater using the switching mode power supply device according to the present invention, the power supply device is characterized in that the power factor is kept constant according to the output capacity, so that the voltage and current are outputted in the form of a sine wave.

A switching mode power supply apparatus to which a power factor correction circuit is applied to transmit a signal transmitted from a base station to a terminal or a base station according to an embodiment of the present invention is characterized in that noise included in an AC power source applied through a first normal mode filter A rectifier for rectifying the AC power supplied through the line filter to the second normal mode filter by rectifying the AC power supplied through the line filter, and a noise and a switch mode power supply included in the DC power supplied through the rectifier A second normal mode filter for eliminating noise from the base station or an output unit for supplying a constant power for a mobile communication relay service between the base station and the terminal.

Further, in the switching mode power supply apparatus to which the power factor correction circuit according to the present invention is applied, the second normal mode filter is characterized in that it is outputted from the common mode filter of the line filter to remove the normal mode noise of the DC power source through the rectifying section .

In addition, the switching mode power supply apparatus to which the power factor correction circuit according to the present invention is applied may further include a switching unit connected to the output terminal of the rectifying unit to increase the direct current power to a voltage corresponding to the output of the power supplying apparatus, .

In addition, in the switching mode power supply apparatus to which the power factor correction circuit according to the present invention is applied, a current is applied in order to supply a constant DC voltage to the lower stage regardless of the magnitude of the AC voltage input to the AC input terminal by controlling the switching unit And a PFC controller for controlling the time.

In the switching mode power supply apparatus to which the power factor correction circuit according to the present invention is applied, the output unit maintains a constant power factor according to the output capacitance, so that the voltage and current are outputted in the form of a sine wave.

According to the present invention, by incorporating a power factor correction circuit in the power supply device, the reactive power of the load is reduced, thereby minimizing the distortion of the input current waveform due to the power factor compensation, thereby ensuring a high power factor in a wide output range. The power factor variation can be minimized according to the output fluctuation. This has the effect of improving the power factor of the load, improving the life of the load, and reducing the electric charge.

Also, by providing an EMI filter technology that can guarantee a high power factor over a wide output range in order to minimize the input current waveform distortion generated by the capacitor, it is possible to reduce noise and AC input signals output from the power supply device employing the power factor correction circuit EMI can be reduced.

In addition, the power factor compensation circuit equipped with the normal mode inductor (Normal Mode Inductor) changes the position and configuration of the normal mode filter so that the same EMI effect is provided using a capacitor of a small capacity, It is possible to prevent the power factor from being lowered.

1 is a block diagram of a mobile communication repeater system using a switching mode power supply apparatus to which a power factor correction circuit according to an embodiment of the present invention is applied.
2 is a block diagram showing a schematic configuration of a switching mode power supply apparatus according to an embodiment of the present invention.
3 is a circuit diagram showing a configuration of a switching mode power supply apparatus to which a power factor correction circuit according to an embodiment of the present invention is applied.
4 is a diagram showing voltage and current waveforms of a power supply device to which a conventional power factor correction circuit is not applied.
5 is a diagram showing voltage and current waveforms of a power supply apparatus to which a power factor correction circuit according to an embodiment of the present invention is applied.
6 is a diagram illustrating EMI characteristics of a conventional power supply apparatus using a noise canceling method.
FIG. 7 is a diagram illustrating EMI characteristics of a power supply apparatus to which a power factor compensation circuit according to an embodiment of the present invention is applied.

In the following description, only parts necessary for understanding the embodiments of the present invention will be described, and the description of other parts will be omitted so as not to obscure the gist of the present invention.

The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary meanings and the inventor is not limited to the meaning of the terms in order to describe his invention in the best way. It should be interpreted as meaning and concept consistent with the technical idea of the present invention. Therefore, the embodiments described in the present specification and the configurations shown in the drawings are merely preferred embodiments of the present invention and do not represent all the technical ideas of the present invention, so that various equivalents And variations are possible.

The power supply apparatus according to an embodiment of the present invention is a switching mode power supply apparatus to which a power factor correction circuit is applied, and is applied to a mobile communication repeater.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a mobile communication repeater system using a switching mode power supply apparatus to which a power factor correction circuit according to an embodiment of the present invention is applied.

Referring to FIG. 1, a mobile communication repeater system 100 according to the present invention includes a base station 10, a terminal 20, and a repeater 30. The repeater 30 includes an upstream signal processing unit 31, a downstream signal processing unit 32, and a power supply unit 33.

The mobile communication repeater system 100 receives an uplink signal transmitted from the terminal 20 through a main antenna among a plurality of antennas for transmitting and receiving radio signals to and from the terminal 20 and transmits the uplink signal to the base station 10, And transmits the downlink signal to the terminal 20.

The mobile communication repeater system 100 according to the present invention is a system in which a path for transmitting a downlink signal from a base station 10 to a terminal 20 is referred to as a forward path and a reverse path is referred to as a forward path from a terminal 20 to a base station 10 And a path for transmitting the uplink signal is divided into reverse paths.

The repeater 30 is connected to the base station 10 through an optical line and transmits an uplink signal through an optical signal to the base station 10. In addition, And transmit and receive downlink signals.

The repeater 30 includes an uplink signal processing unit 31 for receiving a downlink signal transmitted from the base station 10 and transmitting the uplink signal to the terminal 20 and an uplink signal transmitted from the terminal 10 to the base station 10 And a downlink signal processing unit 32 for performing downlink signal processing.

The upstream signal processing unit 31 and the downstream signal unit 32 include an isolator, an attenuator (PAD, ATT), an amplifier (AMP), a bandpass filter (BPF), and a high power amplifier (HPA). That is, the upstream signal processing unit 31 and the downstream signal processing unit 32 receive the high-frequency signals received by the plurality of antennas through the isolator and repeat the signal attenuation and amplification through the multi-stage attenuator and the amplifier, Adjust to a certain level. In addition, the upstream signal processing unit 31 and the downstream signal processing unit 32 filter the out-of-band noise signal through the band-pass filter, amplify it with high power through the high-power amplifier, and transmit it as a radio signal.

The power supply unit 33 supplies power for the repeater 30 to communicate with the base station 10 and the terminal 20. In particular, the power supply unit 33 according to the present invention applies a power factor compensation circuit to minimize input current waveform distortion due to power factor compensation by supplying power for a mobile communication relay service and reducing reactive power of the load have. Accordingly, the mobile communication repeater system 100 having the power supply unit 33 can transmit the signal transmitted from the base station 10 to the terminal 20 or another repeater.

2 is a block diagram showing a schematic configuration of a switching mode power supply apparatus according to an embodiment of the present invention.

2, a switching mode power supply 33 according to an embodiment of the present invention includes a first normal mode filter 310, a line filter 320, a rectifier 330, a second normal mode filter 340, A switching unit 350, and a PFC control unit 360. [

The power supply device 33 to which the power factor correction circuit is applied is constructed by adopting a common mode filter and a normal mode filter as a power filter in order to prevent electromagnetic interference. Here, the power filter removes the noise coming from the outside and prevents the noise generated in the inside from going out.

The power supply unit 33 receives an AC power source having a sinusoidal wave as an input potential of the AC power source and a potential value corresponding to a reference value (i.e., 0 V) from the AC power source. The power supply unit 33 includes an input terminal ACL and ACN for receiving AC power as a commercial power source, a first normal mode filter for removing normal mode noise by receiving AC power from an AC input terminal, 310).

The line filter 320 includes a fuse that turns off the input power when an excessive current is generated due to an abnormality in the repeater 30. The line filter 320 includes a capacitor for removing noise included in the AC power applied through the first normal mode filter 310, a magnetic flux of a current flowing in a reverse direction through an AC power source, And a capacitor for bypassing noise flowing through the coil to remove high-frequency noise. That is, the line filter unit 320 includes an inductor and a capacitor, and their combined capacitors remove high frequency and low frequency noise, for example electromagnetic interference (EMI), from the input side. The AC power output from the line filter 320 is input to the rectifier 330.

The rectifying part 330 is in the form of a bridge diode, and is constituted by four diodes, and the bridge rectifying circuit converts all one period of the alternating current into direct current. Then, the rectified current is input to the second normal mode filter 340.

The second normal mode filter 340 is for improving the power efficiency by correcting the power factor of the external commercial AC power, and is a ratio of the apparent power (voltage-current) supplied to the circuit to the actual power supplied to the load , And improves the power factor. That is, the second normal mode filter 340 is outputted from the common mode filter of the line filter 320 and removes the normal mode noise of the DC power source through the rectifier 330.

The switching unit 350 is connected to the output terminal of the rectifying unit 330 under the control of the PFC controller 360 to increase the DC power to a voltage corresponding to the output of the power supply unit 33, do.

The PFC controller 360 controls the switching unit 350 to supply the DC 390V to the negative terminal connected to the switching mode power supply unit 33 regardless of the magnitude of the AC voltage input to the AC input terminal, And supplies a control signal to the switching unit 350 to generate a control signal for controlling the time for applying the current to maintain the DC voltage of ~ 400V.

An output unit (not shown) supplies a constant power for the mobile communication relay service between the base station 30 or the terminal. Here, the output unit keeps the power factor constant according to the output capacitance, and outputs the voltage and current in a sine wave form.

3 is a circuit diagram showing a configuration of a switching mode power supply apparatus to which a power factor correction circuit according to an embodiment of the present invention is applied.

Referring to FIG. 3, a power supply unit 33 according to the present invention supplies power for a mobile communication relay service and includes a power factor correction circuit. In particular, the mobile communication repeater system 100 having the power supply unit 33 can transmit a signal transmitted from the base station 10 to the terminal 20 or another repeater.

The power factor compensating circuit according to the present invention can be implemented by replacing a capacitor of a high capacitance applied to an EMI filter with a capacitor of a small capacity so that the output of the power supply device 33 We propose a method to prevent the power factor from dropping due to the change. That is, the power factor according to the present invention is a ratio of the amount of electric power used as the active power among the apparent electric powers and has a value between 0 and 1, and may be expressed as a percentage (%). In this case, the apparent power is obtained by taking the square root of the sum of squares of the effective power and the reactive power, and the apparent power is VA, the effective power is W, and the reactive power is used in units of Var.

In addition, the power supply unit 33 for improving the power factor can be driven in a continuous current mode in order to increase the efficiency by continuously operating the current of the step-up reactor of the converter.

The operation of the power supply unit 33 will be described in detail. The power supply unit 33 rectifies the AC input supplied from the AC power supply and the AC power supplied through the power supply unit, and regulates the power factor of the rectified voltage and current . Here, the power supply unit 33 includes a first normal mode filter 310, a line filter 320, and a second normal mode filter 330 for removing noise.

That is, the power supply unit 33 receives an AC power source having a sinusoidal wave as an input potential of the AC power source, and a potential value corresponding to the reference value is input to the reference power source of the AC power source. The power supply unit 33 includes a first normal mode filter 310 for receiving AC power from a commercial power source and an AC power from an AC input terminal to remove normal mode noise, . At this time, the first normal mode filter 310 is composed of inductors L1 and L2 for eliminating the normal mode noise of the AC power source.

The line filter 320 has a fuse F1 which cuts off the input power when an excessive current is generated due to an abnormality in the repeater 30. The line filter 320 includes capacitors C1, C2, and C3 for removing noise included in the AC power applied through the first normal mode filter 310, capacitors C1, C2, and C3, a capacitor C1, A coil LF1 for canceling magnetic flux of a current flowing in a reverse direction by receiving power, and capacitors C4 and C5 for bypassing noise flowing through the coil LF1 to remove noise in a high frequency band. In other words, the line filter unit 320 includes an inductor LF1 and capacitors C1 to C5. These combined capacitors remove high frequency and low frequency noise, for example electromagnetic interference (EMI), from the input side . The AC power output from the line filter 320 is input to the rectifier 330.

The rectifying part 330 is in the form of a bridge die rod, and is constituted by four diodes, and this bridge rectifying circuit converts one period of the alternating current into direct current. Then, the rectified current is input to the second normal mode filter 340. That is, the rectification section BD1 rectifies the AC input supplied from the AC power supply in accordance with the switching of the semiconductor switch Q1 and supplies it to the inductors L3 and L4. For this, the rectifying part BD1 is constituted by the first to fourth rectifying diodes, and the two rectifying diodes are conducted in accordance with the polarity of the input supplied from the AC power source to rectify the AC input supplied from the AC power source so that the inductors L3, L4. That is, the rectification unit BD2 conducts the first and fourth rectification diodes during half cycle of the AC power supply, and the second and third rectification diodes conduct during the remaining half cycle.

The second normal mode filter 340 is provided for improving the power efficiency by correcting the power factor of the external commercial AC power supply. The second normal mode filter 340 provides a function for improving the power factor. That is, the second normal mode filter 340 is outputted from the common mode filter of the line filter 320 and removes the normal mode noise of the DC power source through the rectifier 330. At this time, the second normal mode filter 340 is formed of inductors L3 and L4 to remove the normal mode noise of the AC power source.

The switching unit 350 is connected to the output terminal of the rectifying unit 330 under the control of the PFC controller 360 to increase the DC power to a voltage corresponding to the output of the power supply unit 33, do. At this time, the switching unit 350 includes diodes D1, D2, and D3, a switching transistor Q1, and the like that prevent a current from flowing in a reverse direction.

The PFC controller 360 controls the switching unit 350 to constantly supply a direct current voltage of DC 390 V to 400 V to the lower stage connected to the switching mode power supply unit 33. Accordingly, the power supply unit 33 supplies stable power to the repeater 30 for the mobile communication relay service between the base station 10 or the terminal 20.

4 is a diagram showing voltage and current waveforms of a power supply device to which a conventional power factor correction circuit is not applied. 5 is a diagram showing voltage and current waveforms of a power supply apparatus to which a power factor correction circuit according to an embodiment of the present invention is applied.

Referring to FIG. 5, waveforms of voltage and current of the power supply device 33 according to the present invention are shown. Here, in the mobile communication repeater system 100, the power supply device 33 to which the power factor correction circuit is applied can confirm that the voltage and current are outputted in the form of a sine wave.

Table 1 below shows the EMI waveforms, power factor comparison, and THD (total) output according to the conventional noise removing method and the noise removing method according to the present invention in a power supply apparatus using a power factor compensating circuit having a capacity of 1 kW according to the present invention. harmonic distortion, total harmonic distortion).

Conventional Noise Reduction Method The noise reduction method of the present invention THD PF THD PF When outputting SMPS 200W 20.6% 89% 14.9% 98.7% SMPS 400W output 11.9% 96% 9.8% 99.3% At SMPS 600W output 8.5% 98.2% 7.1% 99.7% SMPS 800W output 7.0% 98.9% 6.2% 99.8% SMPS 1000W output 6.3% 99.2% 5.8% 99.9%

That is, as shown in Table 1, the noise reduction method of the present invention can numerically confirm that the THD is improved as compared with the conventional noise reduction method in the power supply device with the power factor correction circuit incorporated therein. At this time, the normal mode inductor mounted on the back of AC input and bridge diode also improves THD, so high power efficiency due to high power factor, high THD reduction and EMI reduction can be expected for high power quality.

For example, according to the conventional noise canceling method at the output of SMPS 200W, THD (20.6%) and PF (89%) were measured. However, as a result of applying the noise reduction method of the present invention, THD (14.9% PF (98.7%), respectively. According to the noise reduction method of the present invention, THD (9.8%) was lowered and PF (96%) was measured. 99.3%). According to the noise reduction method of the present invention, THD (6.2%) and PF (98.2%) were measured by the conventional noise elimination method at the SMPS 600W output, 99.8%). According to the conventional noise canceling method, the THD (7.0%) and PF (98.9%) were measured at the SMPS output of 800 W. However, as a result of applying the noise reduction method of the present invention, THD (6.2% 99.8%). According to the noise reduction method of the present invention, THD (6.3%) and PF (99.2%) were measured according to the conventional noise canceling method at the output of SMPS 1000W. 99.9%).

6 is a diagram illustrating EMI characteristics of a conventional power supply apparatus using a noise canceling method. FIG. 7 is a diagram illustrating EMI characteristics of a power supply apparatus to which a power factor compensation circuit according to an embodiment of the present invention is applied.

Referring to FIGS. 6 and 7, the present invention maintains a constant power factor according to the output capacitance, and THD and EMI characteristics are also improved. Accordingly, the power supply device 33 to which the power factor correction circuit is applied in the mobile communication repeater system 100 can output voltages and currents close to the sine wave form.

It should be noted that the embodiments disclosed in the present specification and drawings are only illustrative of specific examples for the purpose of understanding, and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein. Furthermore, although specific terms are used in this specification and the drawings, they are used in a generic sense only to facilitate the description of the invention and to facilitate understanding of the invention, and are not intended to limit the scope of the invention.

The present invention can reduce the apparent power by applying the power supply device to which the power factor correction circuit is applied to the mobile communication relay system, thereby saving energy. By reducing the reactive power of the load by incorporating a power factor compensation circuit in the power supply unit, it is possible to minimize the distortion of the input current waveform due to the power factor compensation, thereby ensuring a high power factor in a wide power range, So that the power factor variation can be minimized. This can improve the power factor of the load, improve the life of the load and reduce the electricity bill. Also, by providing an EMI filter technology that can guarantee a high power factor over a wide output range in order to minimize the input current waveform distortion generated by the capacitor, it is possible to reduce noise and AC input signals output from the power supply device employing the power factor correction circuit EMI can be reduced. In addition, the power factor compensation circuit equipped with the normal mode inductor uses the capacitor of a small capacity by changing the position and configuration of the normal mode filter to provide the same EMI effect as the conventional one, and to prevent the power factor from being lowered can do. This is not only a possibility of commercialization or sales, but also a possibility of being industrially applicable since it is practically possible to carry out clearly.

10: base station 20:
30: Repeater 31: Upstream signal processor
32: Downstream signal processing unit 33: Power supply unit
310: first normal mode filter 320: line filter section
330: rectification part 340: second normal mode filter
350: switching part 360: PFC control part
100: Mobile communication repeater system

Claims (8)

1. A mobile communication repeater using a switching mode power supply device to which a power factor correction circuit (PFC) is applied that is adapted to send a signal transmitted from a base station to a terminal or a base station,
An uplink signal processor for receiving a downlink signal transmitted from the base station and transmitting the downlink signal to at least one terminal;
A downlink signal processor for receiving an uplink signal transmitted from the terminal and transmitting the uplink signal to a base station; And
A power supply unit having at least one power factor correction circuit for supplying power for a mobile communication relay service between the base station and the terminal;
, The power supply device
A first normal mode filter that receives AC power from an AC input terminal and removes normal mode noise, a line filter that removes noise included in an AC power applied through the first normal mode filter by a synthetic capacitor, A rectifier for rectifying the AC power supplied through the line filter to a DC power source and supplying the AC power to a second normal mode filter; and a noise generator for generating noise from the DC power supplied through the rectifier and noise generated from the switching- An output unit for supplying a constant power for the second normal mode filter and the mobile communication relay service between the base station and the terminal;
Wherein the power factor compensating circuit is applied to the switching power supply. The power supply apparatus according to claim 1,
Wherein a normal mode noise of a direct current power source which is outputted from a common mode filter of a line filter and which has passed through a rectifying section is removed by a plurality of normal mode filters. The power supply apparatus according to claim 1,
Wherein the power factor is constantly maintained in accordance with the output capacity so that the voltage and current are output in a sinusoidal form. A switching mode power supply apparatus to which a power factor correction circuit is applied that is adapted to transmit a signal transmitted from a base station to a terminal or a base station,
A first normal mode filter for receiving AC power from an AC input terminal to remove normal mode noise;
A line filter for removing noise included in the AC power applied through the first normal mode filter by a synthetic capacitor;
A rectifier for rectifying the AC power supplied through the line filter to a DC power and supplying the rectified AC power to a second normal mode filter;
The second normal mode filter improving the power factor by removing noise included in the DC power applied through the rectifying unit and noise generated in the switching mode power supply unit; And
An output unit for supplying a constant power for the mobile communication relay service between the base station and the terminal;
Wherein the power factor compensation circuit is applied to the switching power supply. 5. The apparatus of claim 4, wherein the second normal mode filter
Wherein the normal mode noise of the direct current power outputted from the common mode filter of the line filter and passed through the rectifying unit is eliminated. 5. The method of claim 4,
A switching unit connected to an output terminal of the rectifying unit to increase the DC power to a voltage corresponding to the output of the power supply unit and output the DC power;
Wherein the power factor correction circuit is applied to the switching power supply. The method according to claim 6,
A PFC controller for controlling a time when the current is applied to supply a constant DC voltage to the lower stage regardless of the magnitude of the AC voltage input to the AC input terminal by controlling the switching unit;
Wherein the power factor correction circuit is applied to the switching power supply. 5. The apparatus of claim 4, wherein the output
Wherein the power factor is constantly maintained in accordance with the output capacity so that the voltage and the current are outputted in the form of a sine wave.

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