Abstract:
There are provided a power supplying apparatus controlling voltage of a power factor correcting circuit according to a power state and a power charging apparatus controlling voltage of a power factor correcting circuit according to a charging state of a battery. The power supplying apparatus includes: a power factor correcting circuit switching input power to correct a power factor thereof and adjusting a voltage level of the power of which the power factor has been corrected according to a state of power transferred to a load; and a resonant DC to DC converting circuit having a resonance frequency varied according to a voltage level of DC power from the power factor correcting circuit and converting the DC power from the power factor correcting circuit into supply power having a preset level according to the resonance frequency.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the priority of Korean Patent Application No. 10-2012-0044831 filed on Apr. 27, 2012, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a power supplying apparatus having increased power converting efficiency and a power charging apparatus having increased charging efficiency. 
         [0004]    2. Description of the Related Art 
         [0005]    Generally, in order to drive an electronic apparatus, a power supplying apparatus supplying driving power, required for driving, is necessarily required. 
         [0006]    This power supplying apparatus generally converts commercial alternating current (AC) power into direct current (DC) driving power to supply the driving power to the electronic apparatus. However, in the power supplying apparatus, a voltage level at which a power converting circuit directly converting the commercial AC power into the driving power may maintain maximum power converting efficiency is limited, such that it is difficult to maintain high power converting efficiency in a wide input voltage level range. Further, in the case in which power is converted in a multi-step scheme, since the power is converted through several operations, power converting efficiency is reduced. 
         [0007]    That is, in this power supplying apparatus, as described in the following Related Art Document, a power factor correcting circuit converting a rectified power into DC power and a DC-DC converting circuit converting the DC power into driving power capable of being used in an electronic apparatus may be employed. However, in this power supplying apparatus, power converting efficiency is reduced in a power converting process. 
         [0008]    Meanwhile, in the case in which the electronic apparatus includes a battery, the above-mentioned power supplying apparatus may be a power charging apparatus providing charging power to be stored in the battery. However, even in this case, power converting efficiency is reduced in a power converting process. 
       RELATED ART DOCUMENT 
       [0000]    
       
         (Patent Document 1) Korean Patent Laid-open Publication No. 10-2009-0098569 
       
     
       SUMMARY OF THE INVENTION 
       [0010]    An aspect of the present invention provides a power supplying apparatus controlling voltage of a power factor correcting circuit according to a power state and a power charging apparatus controlling voltage of a power factor correcting circuit according to a charging state. 
         [0011]    According to an aspect of the present invention, there is provided a power supplying apparatus including: a power factor correcting circuit switching input power to correct a power factor thereof and adjusting a voltage level of the power of which the power factor has been corrected according to a state of power transferred to a load; and a resonant direct current (DC) to DC converting circuit having a resonance frequency varied according to a voltage level of DC power from the power factor correcting circuit and converting the DC power from the power factor correcting circuit into supply power having a preset level according to the resonance frequency. 
         [0012]    The power factor correcting circuit may lower the voltage level of the power of which the power factor has been corrected according to the state of the power transferred to the load. 
         [0013]    The resonant DC to DC converting circuit may lower the resonance frequency according to the voltage level of the power lowered in the power factor correcting circuit. 
         [0014]    The power factor correcting circuit may include a power factor correcting unit switching the input power to correct the power factor thereof and lowering the voltage level of the power of which the power factor has been corrected, and a first controlling unit controlling the lowering of the voltage level of the power in the power factor correcting unit according to the state of the power transferred to the load. 
         [0015]    The resonant DC to DC converting circuit may include a converting unit converting the DC power from the power factor correcting unit into the supply power according to the resonance frequency, and a second controlling unit controlling the lowering of the resonance frequency according to the voltage level of the DC power from the power factor correcting circuit and transferring information on the state of the power transferred to the load to the first controlling unit. 
         [0016]    The converting unit may convert the DC power from the power factor correcting circuit into the supply power in an inductor-inductor-capacitor (LLC) resonance scheme. 
         [0017]    According to another aspect of the present invention, there is provided a power charging apparatus including: a power factor correcting circuit switching input power to correct a power factor thereof and adjusting a voltage level of the power of which the power factor has been corrected according to a charging state of a battery; a resonant DC to DC converting circuit having a resonance frequency varied according to a voltage level of DC power from the power factor correcting circuit and converting the DC power from the power factor correcting circuit into charging power having a preset level according to the resonance frequency; and a battery unit receiving the charging power and providing information on the charging state of the battery according to the received charging power. 
         [0018]    The power factor correcting circuit may lower the voltage level of the power of which the power factor has been corrected according to the charging state of the battery. 
         [0019]    The resonant DC to DC converting circuit may lower the resonance frequency according to the voltage level of the power lowered in the power factor correcting circuit. 
         [0020]    The power factor correcting circuit may include a power factor correcting unit switching the input power to correct the power factor thereof and lowering the voltage level of the power of which the power factor has been corrected, and a first controlling unit controlling the lowering of the voltage level of the power in the power factor correcting unit according to the charging state of the battery. 
         [0021]    The resonant DC to DC converting circuit may include a converting unit converting the DC power from the power factor correcting circuit into the charging power according to the resonance frequency, and a second controlling unit controlling the lowering of the resonance frequency according to the voltage level of the DC power from the power factor correcting circuit and transferring the information on the charging state of the battery to the first controlling unit. 
         [0022]    The converting unit may convert the DC power from the power factor correcting circuit into the charging power in an inductor-inductor-capacitor (LLC) resonance scheme. 
         [0023]    The battery unit may include a battery charging controlling unit providing the information on the charging state of the battery. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    The above and other aspects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0025]      FIG. 1  is a schematic configuration diagram of a power supplying apparatus according to an embodiment of the present invention; 
           [0026]      FIG. 2  is a schematic configuration diagram of a power charging apparatus according to an embodiment of the present invention; 
           [0027]      FIG. 3  is a graph showing a relationship between a frequency and an alternating current (AC) resistance component; and 
           [0028]      FIG. 4  is a graph showing a relationship between a voltage ratio and a resonance frequency according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0029]    Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that they can be easily practiced by those skilled in the art to which the present invention pertains. 
         [0030]    However, in describing embodiments of the present invention, detailed descriptions related to well-known functions or configurations will be ruled out in order not to unnecessarily obscure subject matters of the present invention. 
         [0031]    In addition, like or similar reference numerals denote parts performing similar functions and actions throughout the drawings. 
         [0032]    It will be understood that when an element is referred to as being “connected to” another element, it can be directly connected to the other element or may be indirectly connected to the other element with element(s) interposed therebetween. 
         [0033]    In addition, unless explicitly described to the contrary, the word “comprise” and variations such as “comprises” or “comprising,” will be understood to imply the inclusion of stated elements but not the exclusion of any other elements. 
         [0034]    Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. 
         [0035]      FIG. 1  is a schematic configuration diagram of a power supplying apparatus according to an embodiment of the present invention. 
         [0036]    Referring to  FIG. 1 , a power supplying apparatus  100  according to the embodiment of the present invention may include a power factor correcting circuit  110  and a resonant direct current to direct current (DC to DC) converting circuit  120 . 
         [0037]    The power factor correcting circuit  110  may include a power factor correcting unit  111  and a first controlling unit  112 . 
         [0038]    The power factor correcting unit  111  may switch input power to adjust a phase difference between voltage and current of the power, thereby correcting a power factor. In addition, the power factor correcting unit  111  may variably adjust a voltage level of DC power of which the power factor has been corrected according to the switching operation. The variable adjustment of the voltage level may be controlled by the first controlling unit  112 . 
         [0039]    The first controlling unit  112  may control the adjustment of the voltage level of the DC power of which the power factor has been corrected according to the switching of the power factor correcting unit  111  according to information on a state of supply power, and the power factor correcting unit  111  may provide the DC power of which the voltage level is adjusted according to the controlling of the first controlling unit  112 , to the resonant DC to DC converting circuit  120 . 
         [0040]    The power factor correcting unit  111  may provide the DC power having a lowered voltage level to the resonant DC to DC converting circuit  120 . 
         [0041]    The resonant DC to DC converting circuit  120  may include a converting unit  121  and a second controlling unit  122 . 
         [0042]    The converting unit  121  may convert the DC power from the power factor correcting unit  111  into supply power having a preset level. The converting unit  121  may convert the DC power from the power factor correcting unit  111  into the supply power in a preset resonance scheme. 
         [0043]    In this case, the converting unit  121  may perform a power converting operation using a resonance frequency. The resonance frequency may be affected by the voltage level of the DC power. A detailed description thereof will be provided below with reference to  FIGS. 3 and 4 . 
         [0044]    The second controlling unit  122  may set the resonance frequency according to information on the state of the power transferred from a load unit  130  to control the power converting operation of the converting unit  121 . 
         [0045]    When the voltage level of the DC power is lowered in the power factor correcting unit  111 , a frequency value of the resonance frequency may be lowered. 
         [0046]    The information on the state of the power provided to the second controlling unit  122  may be transferred to the first controlling unit  112 . 
         [0047]    Meanwhile, the power supplying apparatus according to the embodiment of the present invention described above may be used as a power charging apparatus. 
         [0048]      FIG. 2  is a schematic configuration diagram of a power charging apparatus according to an embodiment of the present invention. 
         [0049]    Referring to  FIG. 2 , a power charging apparatus  200  according to the embodiment of the present invention may include a power factor correcting circuit  210  and a resonant DC to DC converting circuit  220 . 
         [0050]    The power factor correcting circuit  210  may include a power factor correcting unit  211  and a first controlling unit  212 , similar to the power factor correcting circuit  110  of  FIG. 1 . 
         [0051]    The power factor correcting unit  211  may lower a voltage level of DC power according to controlling by the first controlling unit  212 , and the first controlling unit  212  may control the adjustment of the voltage level of the DC power of the power factor correcting unit  211  according to information on a charging state, unlike the first controlling unit  112  of  FIG. 1 . 
         [0052]    In addition, the resonant DC to DC converting circuit  220  may include a converting unit  221  and a second controlling unit  222 . 
         [0053]    The converting unit  221  may convert the DC power from the power factor correcting unit  211  into charging power in a preset resonance scheme according to controlling by the second controlling unit  222 . The second controlling unit  222  may adjust a resonance frequency value of the converting unit  221  according to the information on the charging state, unlike the second controlling unit  122   FIG. 1 . 
         [0054]    More specifically, the second controlling unit  222  may receive information regarding a current voltage/current level of a battery and a target voltage/current level thereof and determine voltage and current levels of the charging power according to the target voltage/current level included in the information on the charging state to control a power converting operation of the converting unit  221 . 
         [0055]    In addition, the second controlling unit  222  may provide the target voltage level of the DC power to the first controlling unit  212 , and the first controlling unit  212  may control power switching of the power factor correcting unit  211  according to the target voltage level. 
         [0056]    In this case, the first controlling unit  212  may determine the voltage level of the DC power within a range in which a problem does not occur in power factor correction according to an AC voltage level state of input power. Here, the adjusted voltage level of the DC power may be larger than a feed voltage level of the AC voltage of the input power. 
         [0057]    In addition, the power charging apparatus  200  according to the embodiment of the present invention may further include a battery unit  230 . The battery unit  230  may include a battery  231  receiving the charging power from the resonant DC to DC converting circuit  220  to thereby be charged with the charging power and a battery charging controlling unit  232  controlling a charging state of the battery  231  and providing information on the charging state of the battery  231  to the second controlling unit  222 . 
         [0058]      FIG. 3  is a graph showing a relationship between a frequency and an AC resistance component. 
         [0059]    First, the resonant DC to DC converting circuit  120  or  220  may convert power in a preset resonance scheme. Therefore, although not shown, the resonant DC to DC converting circuit  120  or  220  may generally include a switch switching power and a transformer varying a voltage level of the power and may further include passive devices such as an inductor, a capacitor, and the like, according to a resonance scheme. As the resonance scheme, various schemes using a resonance frequency may be used. For example, an inductor-inductor-capacitor (LLC) resonance scheme may be used. 
         [0060]    In the case of devices using a coil, such as a transformer and an inductor, winding loss according to an operating frequency may be generated, which may be in proportion to AC resistance. 
         [0061]    Referring to  FIG. 3 , the frequency and the AC resistance may be in proportion to each other. 
         [0062]    That is, when an operating frequency is high, AC resistance is increased, such that the winding loss may increase in the device using the coil, such as the transformer and the inductor. Further, in the case of switching the power, switching loss may increase. 
         [0063]      FIG. 4  is a graph showing a relationship between a voltage ratio and a resonance frequency according to the embodiment of the present invention. 
         [0064]    More specifically, the graph of  FIG. 4  shows a relationship between a resonance frequency and a voltage ratio between the voltage level of the DC power from the power factor correcting circuit  110  or  210  and the voltage level of the supply power or the charging power transferred from the resonant DC to DC converting circuit  120  or  220  to the load unit  130  or the battery  231 . 
         [0065]    Referring to  FIG. 4 , the supply power or the charging power from the resonant DC to DC converting circuit  120  or  220  may have a resonance curve of high voltage and low current ‘a’ or low voltage and high current ‘b’. 
         [0066]    The above-mentioned resonance curve may have first and second regions respectively positioned at the left and the right based on a maximum resonance point frequency. In the case in which the resonance frequency is significantly lower than the maximum resonance point frequency, volume of the passive device increases, such that the first region is not used. 
         [0067]    That is, in the second region of the resonance curve, the voltage ratio between the voltage level of the DC power and the voltage level of the supply power or the charging power and the resonance frequency may be in inverse proportion to each other. More specifically, when the voltage ratio increases, the resonance frequency may decrease. 
         [0068]    For example, in the case in which the voltage level of the DC power from the power factor correcting circuit  110  or  210  is 400V, when the voltage level of the supply power or the charging power is set to 200V and power conversion is performed, a voltage ratio may be 0.5. However, in the case in which the voltage level of the DC power from the power factor correcting circuit  110  or  210  is lowered to 350V according to a power state or a charging state, when the voltage level of the supply power or the charging power is set to 200V and power conversion is performed, a voltage ratio may be 0.57. 
         [0069]    In this case, it may be appreciated that a frequency F 2  when the voltage ratio is 0.57 is lower than a frequency F 1  when the voltage ratio is 0.5. Therefore, winding loss and switching loss may be reduced according to an electrical relationship as shown in  FIG. 3 . 
         [0070]    As set forth above, according to the embodiments of the present invention, a voltage level of a power factor correcting circuit is controlled according to a power state or a charging state to significantly reduce shifting of a resonance frequency of a resonant circuit and reduce switching loss and winding loss, whereby power converting efficiency may be increased. 
         [0071]    While the present invention has been shown and described in connection with the embodiments, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the spirit and scope of the invention as defined by the appended claims.