Patent Abstract:
A non-contact power charging, in which power transmission can be interrupted when foreign materials are deposited on a charge plate of the non-contact power charging system. A charging operation can be continuously maintained at a stable voltage even if a non-contact power receiving apparatus moves by touching or displacement on the charge plate of the non-contact power charging system in the charging operation. Charging efficiency is improved.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. application Ser. No. 13/226,769, filed Sep. 7, 2011 in the U.S. Patent and Trademark Office, which is a continuation of U.S. application Ser. No. 12/166,527, filed Jul. 2, 2008 in the U.S. Patent and Trademark Office, now patented as U.S. Pat. No. 8,030,887, issued Oct. 4, 2011, which claims the benefit of Korean Application No. 10-2008-0015114, filed Feb. 20, 2008, in the Korean Intellectual Property Office. All disclosures of the document(s) named above are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a power charging system, and more particularly, to a non-contact power charging system and a control method thereof, in which power transmission can be interrupted when foreign materials are deposited on a charge plate of the non-contact power charging system, a charging operation can be continuously maintained at a stable voltage even if a non-contact power receiving apparatus moves by touching or displacement on the charge plate of the non-contact power charging system in the charging operation, and thus charging efficiency can be improved. 
         [0004]    2. Description of the Related Art 
         [0005]    Portable electronic devices, such as cellular phones, personal digital assistants (PDAs), portable media players (PMPs), digital multimedia broadcasting terminal (DMB terminals), MPEG audio layer 3 (MP3) players or notebook computers, cannot be plugged into a regular power source at home or office since they are generally used while the users are moving. Accordingly, the portable electronic devices are equipped with batteries or rechargeable batteries. 
         [0006]    A charging system has been used to charge electric power, supplied from the regular power source, to the batteries or a battery pack of the portable devices via power supply lines or power supply connectors. However, when the charger and the batteries are connected or disconnected to replenish the electric power of the batteries with this connector supply system, an instant discharge may happen because of the potential differences between the charger connector and the battery connector. Hence the foreign substances will be gradually gathered on both connectors and finally there may be a fire disaster. Further, the collected humidity thereon will cause the discharge of the battery and other problems will be involved like the declining battery life, the low battery quality, and so on. 
         [0007]    To solve the above-mentioned problems of the connector supply system, non-contacting charging systems have been developed. In this non-contacting charging system in accordance with the prior art, the device having the battery to be charged is placed over the primary coil of the non-contacting charging system and the battery will be charged by a secondary coil of the battery. The battery is charged with the induced electricity from the induced electromotive force of the secondary coil by the generated magnetic field from the primary coil. 
         [0008]    The existing non-contacting charging systems with the prior art can only be used to supply the electricity to the portable devices. There are limited practical uses because they cannot be used in various alternatives. 
         [0009]    Besides, if a metal is placed inside the effective radius of the generated magnetic field of the primary coil, there would be a lot loss of the electricity in the primary coil due to the changes of the magnetic field, so that non-contacting charging system may be damaged. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention has been made to solve the foregoing problems with the prior art, and therefore the present invention is directed to prevent a non-contact power receiving apparatus and a non-contact power transmission apparatus by stopping power transmission when a foreign material is deposited on a charge plate. 
         [0011]    The present invention is also directed to improve charging efficiency by ensuring that a charging operation be performed at a stable voltage even if the non-contact power receiving apparatus moves by touching or displacement on the charge plate of the non-contact power transmission apparatus while being powered. 
         [0012]    Further, the present invention is also directed to protect a battery cell from a magnetic field created by primary and secondary charge cores such that the battery cell can be stably charged. 
         [0013]    According to an aspect of the present invention, there is provided a non-contact power charging system, including a non-contact power transmission apparatus generating a power signal at a primary charge core thereof; and a non-contact power receiving apparatus receiving the power signal from the non-contact power transmission apparatus so as to be charged with power by the control of the non-contact power charging system. The non-contact power receiving apparatus includes a secondary charge core generating induced current in response to the primary charge core of the non-contact power transmission apparatus; a rectifier block connected to the secondary charge core to rectify the induced current; a charge IC block causing to charge a battery cell with the power from the rectifier block; a received power monitor module monitoring the power received through the secondary charge core; and a power receiver control unit constructed to control the rectifier block, the charge integrated circuit (IC) block and the received power monitor module, and to control identifier (ID) generation and a charge status signal. The received power monitor module includes a low voltage monitor module comparing and discerning whether or not the received power is detected to have a low voltage and a high voltage monitor module comparing and discerning whether or not the received power is detected to have a high voltage. 
         [0014]    According to another aspect of the present invention, there is provided a control method of a non-contact power charging system, which includes a non-contact power transmission apparatus generating a power signal at a primary charge core thereof and a non-contact power receiving apparatus receiving the power signal from the non-contact power transmission apparatus so as to be charged with power. The control method includes procedures: 
         [0015]    transmitting, at the primary core of the non-contact power transmission apparatus, an object detection signal including a call signal that call a unique ID value from the non-contact power receiving apparatus, and standing by for a response signal; 
         [0016]    discerning whether or not a normal unique ID signal is received from the non-contact power receiving apparatus by discerning a signal detected according to load modulation by the primary charge core; 
         [0017]    if it is discerned that a normal unique ID signal is received from the non-contact power receiving apparatus, generating, at the primary charge core through a gate driver module of the non-contact power transmission apparatus, a full power transmission signal; 
         [0018]    requesting charge status information from the non-contact power receiving apparatus and adjusting charge level based on the charge status information received from the non-contact power receiving apparatus; and 
         [0019]    if fully-charged state information is received from the non-contact power receiving apparatus, terminating a charging operation and displaying fully-charged state on a liquid crystal display panel or a charge status indicator light emitting module. 
         [0020]    Here, the procedure of discerning whether or not a normal unique ID signal is received from the non-contact power receiving apparatus by discerning a signal detected according to load modulation by the primary charge core, includes: if the signal detected according to load modulation by the primary charge core is not a normal signal that has normal ID data transmitted from the non-contact power receiving apparatus, converting into a foreign material detection mode; and if a detected foreign material is metal or an electronic device, displaying a foreign material error on the liquid crystal display panel or the charge status indicator light emitting module and terminating a charging operation of a corresponding charging block. 
         [0021]    Further, the procedure of adjusting charge level based on the charge status information received from the non-contact power receiving apparatus, includes: requesting data information on charge status information from the non-contact power receiving apparatus; receiving the charge status information transmitted from the non-contact power receiving apparatus, the charge status information including charged amount information and voltage data of received power; analyzing and discerning data on the charge status information on the power signal, received from the non-contact power receiving apparatus; and calculating a frequency of the power signal in order to compensate for transmission power based on the voltage data, received from the non-contact power receiving apparatus, and transmitting a power signal at a compensated frequency. 
         [0022]    According to a further aspect of the present invention, there is provided a control method of a non-contact power charging system, which includes a non-contact power transmission apparatus generating a power signal from a primary charge core thereof, and a non-contact power receiving apparatus receiving the power signal from the non-contact power transmission apparatus so as to be charged with power. The control method includes procedures of: 
         [0023]    detecting, at the non-contact power receiving apparatus in a standby mode for receiving the power signal, detecting a call signal transmitted together with an object detection signal from the primary charge core of the non-contact power transmission apparatus to call a unique ID value from the non-contact power receiving apparatus, and transmitting a signal related with the call ID value of the non-contact power receiving apparatus to the non-contact power transmission apparatus; 
         [0024]    converting into a charge standby mode after the unique ID value is transmitted, rectifying the power signal transmitted from the non-contact power transmission apparatus and charging a battery cell with the rectified power signal; 
         [0025]    discerning whether or not the power signal transmitted from the non-contact power transmission apparatus has a reference voltage, and transmitting a voltage adjustment signal to request voltage step-up if the discerned power signal is below the reference voltage or to request voltage step-down if the discerned power signal is above the reference voltage; 
         [0026]    after the voltage adjustment signal is transmitted, if a received voltage is the reference voltage, generating a signal indicative of normal reception; and 
         [0027]    discerning whether or not the battery cell is in fully charged status, and if the battery cell is in fully charged status, terminating a charging operation. 
         [0028]    As set forth above, the present invention can prevent the non-contact power receiving apparatus and the non-contact power transmission apparatus from being damaged by stopping power transmission when a foreign material is deposited on the charge plate. 
         [0029]    Further, the present invention can also improve charging efficiency by ensuring that a charging operation be performed at a stable voltage even if the non-contact power receiving apparatus moves by touching or displacement on the charge plate of the non-contact power transmission apparatus while being powered. 
         [0030]    Moreover, the present invention can also protect the battery cell from a magnetic field created by the primary and secondary charge cores such that the battery cell can be stably charged. 
         [0031]    Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0032]    The above and other objects, 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: 
           [0033]      FIG. 1  is a schematic configuration view illustrating a non-contact power transmission apparatus of a non-contact power charging system in accordance with the present invention; 
           [0034]      FIG. 2  is a schematic configuration view illustrating a non-contact power receiving apparatus of the non-contact power charging system in accordance with the present invention; 
           [0035]      FIG. 3  is a flowchart illustrating a non-contact power transmission process of the non-contact power charging system in accordance with the present invention; 
           [0036]      FIG. 4  is a flowchart illustrating a non-contact power receiving process of the non-contact power charging system in accordance with the present invention; 
           [0037]      FIG. 5  is a control flow diagram illustrating a non-contact power transmission process of the non-contact power charging system in accordance with the present invention; 
           [0038]      FIG. 6  is a control flow diagram illustrating a non-contact power receiving process of the non-contact power charging system in accordance with the present invention; 
           [0039]      FIGS. 7 and 8  are circuit diagrams illustrating the non-contact power receiving apparatus of the non-contact power charging system in accordance with the present invention; 
           [0040]      FIG. 9  is an exploded perspective view illustrating the construction of the non-contact power receiving apparatus of the non-contact power charging system in accordance with the present invention; 
           [0041]      FIG. 10  is a side cross-sectional view of  FIG. 9 ; 
           [0042]      FIGS. 11 and 12  are graphs illustrating power control efficiencies of the prior art; 
           [0043]      FIGS. 13 through 16  are graphs illustrating power control efficiencies of the non-contact power charging system in accordance with the present invention; 
           [0044]      FIG. 17  is a graph illustrating efficiencies of repeated charge/discharge test on the non-contact power receiving apparatus of the non-contact power charging system in accordance with the present invention; and 
           [0045]      FIGS. 18 and 19  illustrate operations of the non-contact power charging system in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0046]    Hereinafter, the present invention will be described more fully with reference to the accompanying drawings, in which exemplary embodiments thereof are shown. 
         [0047]      FIG. 1  is a schematic configuration view illustrating a non-contact power transmission apparatus of a non-contact power charging system in accordance with the present invention; 
         [0048]      FIG. 2  is a schematic configuration view illustrating a non-contact power receiving apparatus of the non-contact power charging system in accordance with the present invention;  FIG. 3  is a flowchart illustrating a non-contact power transmission process of the non-contact power charging system in accordance with the present invention;  FIG. 4  is a flowchart illustrating a non-contact power receiving process of the non-contact power charging system in accordance with the present invention;  FIG. 5  is a control flow diagram illustrating a non-contact power transmission process of the non-contact power charging system in accordance with the present invention;  FIG. 6  is a control flow diagram illustrating a non-contact power receiving process of the non-contact power charging system in accordance with the present invention;  FIGS. 7 and 8  are circuit diagrams illustrating the non-contact power receiving apparatus of the non-contact power charging system in accordance with the present invention;  FIG. 9  is an exploded perspective view illustrating the construction of the non-contact power receiving apparatus of the non-contact power charging system in accordance with the present invention;  FIG. 10  is a side cross-sectional view of  FIG. 9 ;  FIGS. 11 to 16  are graphs illustrating power control efficiencies of the non-contact power charging system in accordance with the present invention;  FIG. 17  is a graph illustrating efficiencies of repeated charge/discharge test on the non-contact power receiving apparatus of the non-contact power charging system in accordance with the present invention; and  FIGS. 18 and 19  illustrate operations of the non-contact power charging system in accordance with the present invention. 
         [0049]    Referring to  FIGS. 1 to 19 , a non-contact charging system A of the present invention includes a non-contact power transmission apparatus  10  that is constructed to transmit a power signal to a non-contact power receiving apparatus  30  without actual contacts. 
         [0050]    As shown in  FIG. 1 , the non-contact power transmission apparatus  10  includes a central control unit and a full bridge resonant converter  22 , which act to transmit a power signal to the non-contact power receiving apparatus  30  without actual contacts. 
         [0051]    The non-contact power transmission apparatus  10  also includes a gate driver module  23 , which causes the full bridge resonant converter  22  to transmit a converted power signal, and a received signal processing module  24 , which processes a signal transmitted from the non-contact power receiving apparatus and sends the processed signal to the central control unit  21 . 
         [0052]    The non-contact power transmission apparatus  10  also includes a power transmission apparatus case (not shown). The power transmission apparatus case includes, on the front side thereof, a power on/off switch, an input panel for signal input, a liquid crystal display (LCD) panel  153  and a charge status indicator light emitting diode (LED) module  154 . The LCD panel  153  and the LED module  154  serve to display the status and the charge status of a non-contact charge plate (not shown) and the non-contact power receiving apparatus  30 . Inside the power transmission apparatus case, a power supply unit  25  is installed. 
         [0053]    As such, as shown in  FIG. 1 , the non-contact power receiving apparatus  30  implemented as a battery of a mobile device, such as a mobile phone, a personal digital assistant (PDA), a portable multimedia player (PMP), a digital multimedia broadcasting terminal (DMB terminal), a moving picture experts group (MPEG) audio layer 3 player (MP3 player) or a notebook computer, is mounted on the charge plate of the non-contact power transmission apparatus. When the non-contact power receiving apparatus is placed on the charge plate, the non-contact power transmission apparatus  10  starts a charging operation by detecting the placement of the non-contact power receiving apparatus  30 . 
         [0054]    Below a description will be given of the construction of the central control unit  21  controlling the charging operation of the non-contact power transmission apparatus  10 . As shown in  FIG. 1 , the central control unit  21  includes a power supply block  211  connected to the power supply unit  25  to supply power to the non-contact power transmission apparatus  10 ; a signal output block  212  outputting an indicator signal to the LCD panel  153  and the charge status LED module  154 ; a gate output signal processing block  213  connected to the gate driver module  23  to transmit a control signal in response to an output power signal from a primary charge core  13 ; a received signal processing block  214  connected to the primary charge core  13  to process a signal transmitted from the received signal processing module  24 , which processes a signal transmitted from the non-contact power receiving apparatus  30 ; and a main controller  210  controlling parts of the non-contact power transmission apparatus  10  including the power supply block  211 , the signal output block  212 , the gate output signal processing-block  213 , the received signal processing block  214  and so on. 
         [0055]    The power supplied to the power supply unit  25  may be provided from a universal serial bus (USB) port of a computer, an alternating current (AC) adaptor, a cigar jack and so on. 
         [0056]    The central control unit  21  also includes a temperature detector  26 , which detects the temperature of the non-contact power transmission apparatus  10  during the charging operation. The central control unit  21  can be constructed to interrupt the charging operation when a temperature detected by the temperature detector  26  indicates overheating, or to suspend the operation of the whole system when the detected temperature indicates overheating of the whole part of the non-contact power transmission apparatus  10 . 
         [0057]    A current sensing member may also be provided in each of the power supply unit  25 , the gate driver module  23 , the full bridge resonant converter  22  and the received signal processing module  24  in order to detect a flow of electric current. The non-contact power transmission apparatus  10 , particularly, the central control unit  21  can be constructed to interrupt the charging operation or the operation of the system, and generates a corresponding signal when the current sensing member detects an over-current or over-voltage state from a corresponding part. 
         [0058]    The non-contact power receiving apparatus  30  is an apparatus that receives a power signal from the non-contact power transmission apparatus  10 . As shown in  FIG. 2 , the non-contact power receiving apparatus  30  generally includes a secondary charge core  32  having a construction corresponding to that of the primary charge core  13  of the non-contact power transmission apparatus  10  so as to generate induced current; a rectifier block  33  connected to the secondary charge core  32  to rectify induced current; a smoothing filter block  34  connected to the rectifier block to filter current and power; a charger integrated circuit (IC) block  36  connected to the rectifier block  33  to charge a battery cell  35  with power; a protection circuit module (PCM) block  37  disposed between the charger IC block  36  and the battery cell  35  to detect current charged to the battery cell  35  and transmit the charge status information of the battery  35  to a power receiver control unit  39  so as to detect the status of the battery, such over-voltage, under-voltage, over-current and short-circuit; and a static voltage regulator block  38  supplying power to the PCM block  37 . The power receiver control unit is also provided in the non-contact power receiving apparatus  30 , and is constructed to control the rectifier block  33 , the smoothing filter block  34 , the charger IC block  36 , the PCM block  37  and the static voltage regulator block  38  and to monitor an occurrence of an identifier (ID) and a charge status. 
         [0059]    The non-contact power receiving apparatus  30  also includes a received power monitor module  31 , which monitors power received through the secondary charge coil  32 , in order to detect whether or not power is stably received. A reference voltage of a power source, which is received as above, can be variously selected according to the detailed specification of the non-contact power charging system A and the non-contact power receiving apparatus  30 . For example, the reference voltage can be set, generally, in the range from 2 to 20V, and when applied to a typical mobile phone device, on the order of 4V. 
         [0060]    The received power monitor block  31  includes, as subsidiary components thereof, a low voltage monitor module  311  discerning whether or not received power has a low voltage and a high voltage monitor module  312  discerning whether or not received power has a high voltage. 
         [0061]    In the low voltage monitor module  311  as above, the voltage level acting as a reference of a low voltage can be selectively set according to the detailed specification of the non-contact power charging system A and the non-contact power receiving apparatus  30 . The voltage level may be set −1V or −0.5V when the reference voltage is set 5V as in the foregoing illustration. 
         [0062]    Likewise, the voltage level acting as a reference of a low voltage in the high voltage monitor module  312  can also be selectively set according to the detailed specification of the non-contact power charging system A and the non-contact power receiving apparatus  30 . The voltage level may be set +1V or +0.5V when the reference voltage is set 5V as in the foregoing illustration. 
         [0063]    The power receiver control unit  39  includes a power signal processing block  393  connected to the smoothing filter block  34  to process a transmission signal about data information on a power signal transmitted from the non-contact power transmission apparatus  10 ; a charge signal processing block  394  connected to the charge IC block  36  and the PCM block  37  to process a transmission signal about data information on the charge capacity and charge status of the battery cell  35 ; a signal processing block  392  processing charge capacity information and data information on a unique ID, which are transmitted to the non-contact power transmission apparatus  10  by the control of a device controller  390 ; and a device memory  391 . The device memory  391  stores data information on a unique ID, temporarily stores charge capacity information and charge status data, which are transmitted from the PCM block  37  and the charge IC block  36 , and storing data transmitted from the non-contact power transmission apparatus  10 . The device controller  390  is also included in the power receiver control unit  39 . 
         [0064]    Referring to an exemplary construction shown in  FIG. 7 , a part for monitoring the voltage of power transmitted from the non-contact power transmission apparatus  10  is implemented as the received power monitor module  31  separate from the power receiver control unit  39 . 
         [0065]    As such, the monitoring part can be constructed as a separate module from the power receiver control unit  39 . Further, as shown in  FIG. 8 , a single control module can be constructed by integrating the power receiver control unit  39  with a received power monitor block  31 ′. In the case where the power receiver control unit  39  including the received power monitor module  31  (a low voltage monitor block  311 ′ and high voltage monitor block  312 ′) is constructed as a single module, the advantage is that the construction of the non-contact power receiving apparatus  30  can be simplified, thereby reducing the entire size thereof. Another advantage is that lines for monitoring received power can be simplified so as to simplify the entire circuit construction. 
         [0066]    While the foregoing embodiment has been illustrated with respect to a voltage-monitoring construction which monitors a received power signal with reference to the upper or lower limit of a voltage, a current-monitoring construction can also be provided alone or in combination with the voltage-monitoring construction. Of course, it CaO be constructed to monitor both the voltage and the current in order to ensure circuit stability. According to installation conditions, only one of a voltage-monitoring circuit and a current-monitoring circuit can be provided. While following embodiments will be illustrated with respect to the upper or lower limit of a voltage, this is not intended to limit the present invention. Rather, the circuit can also be constructed to monitor received power using the upper and lower limits of current such that power can be stably received. 
         [0067]    The non-contact power charging system A as described above has an advantage in that a power signal transmitted from the non-contact power transmission apparatus  10  is stably received in the non-contact power receiving apparatus  30  such that charging power can be transmitted in optimized conditions. 
         [0068]    Below, a description will be given of the charging operation of the non-contact power charging system A in accordance with the present invention constructed as above. 
         [0069]    In the non-contact power transmission apparatus  10  of the non-contact power charging system A, a power signal is periodically transmitted to the gate output signal processing block  213 , the gate driver module  23 , the full bridge resonant converter block  22  and the primary charge core  13  through gate signal lines  234  by the control of the central control unit  21  (standby mode S 01 ). In the standby mode S 01 , the power signal periodically transmitted through the primary charge core  13  includes a call signal that request a unique ID from the non-contact power receiving apparatus  30 , and the process stands by for a response signal to the call signal. 
         [0070]    In the procedure of standing by for a response signal after the transmission of the unique ID call signal in the standby mode S 01 , an object is detected using a received detection signal in response to load modulation by the primary charge core  13 . The object, which can be placed on the charge plate, may include not only a mobile non-contact power receiving apparatus  30 , such as a mobile phone, a PDA, a PMP, a DMB device, an MP3 player or a notebook computer, but also a metallic object, a non-metallic object and an electronic device incapable of non-contact charging. Accordingly, the non-contact power transmission apparatus  10  discerns whether or not any one of the above-described objects is placed on the charge plate by receiving the detection signal in response to load modulation produced by the object. 
         [0071]    In the case of load modulation caused by the presence of the non-metallic object or the movement of the object, the operation may convert to the standby mode S 01  unless there is a specific problem. However, in the case of the metallic object or electronic device incapable of non-contact charging rather than the non-contact power receiving apparatus  30 , the charging operation may bring in heating or malfunction. 
         [0072]    To this end, a foreign material is monitored by parasitic metal detection (PMD). That is, when the detection signal in response to load modulation caused by an object is detected by the primary charge core  13  and the received signal processing module  24 , this procedure is carried out to discern whether or not the detection signal is a normal signal. Particularly, the procedure discerns whether or not the detection signal is an abnormal signal incapable of signal discerning by comparing the detection signal with a signal generated by the control of the central control unit  21 . If the object is detected as a foreign material, the process converts into a foreign material detection status, causes the LCD panel  153  or the charge status indicator LED module  154  to display a foreign material error (a PMD error) if the foreign material is a metallic object or an electronic device. Further, the charging operation is interrupted. 
         [0073]    If the received detection signal is discerned as data information on the unique ID of the non-contact power receiving apparatus  30  that can be charged without contacts, the received detection signal in response to load modulation is analyzed and discerned (unique ID discerning S 02 ). In the standby mode S 01 , a search signal for the non-contact power receiving apparatus  30  is transmitted and a call signal requesting data information on the unique ID of the non-contact power receiving apparatus is also transmitted. Correspondingly, in the non-contact power receiving apparatus  30 , induced current from the secondary charge core  32  is rectified by the rectifier block  33  and is then filtered by the smoothing filter block  34 . During this procedure, the call signal requesting the unique ID data information is transmitted to the device controller  390  of the power receiver control unit, and correspondingly, unique ID data of the non-contact power receiving apparatus  30  stored in the device memory  391  is transmitted to the non-contact power transmission apparatus  10  through the signal processing block  392 . Then, the main control unit  210  discerns whether or not the corresponding non-contact power receiving apparatus is a normal apparatus that can be charged without contacts. That is, the main control unit  210  discerns whether or not the received data is a unique ID data type of a normal non-contact power receiving apparatus, and then discerns whether or not the received data is unique ID data transmitted from a normal non-contact power receiving apparatus. 
         [0074]    If the received data is discerned as unique ID data transmitted from a normal non-contact power receiving apparatus, the primary charge core  13  is caused to generate a full power transmission signal through the gate driver module  23  (full power transmission S 03 ). 
         [0075]    Describing the full power transmission S 03  in the non-contact power transmission apparatus  10 , the main controller  210  of the central control unit  21  determines that a normal non-contact power receiving apparatus is placed on the charge plate (not shown), thereby generating a control signal to transmit a power signal through the gate output signal processing block  213  and the gate signal lines  234 . 
         [0076]    The control signal generated as above is transmitted to the gate driver module  23  and is transmitted through the full bridge resonant converter  22  to the primary charge core  13 , which then generates an induced magnetic field, such that the power signal is transmitted to the non-contact power receiving apparatus. 
         [0077]    The gate signal lines  234  and the gate driver module  23 , associated with the above-described process, can have a construction as rendered in a following embodiment. 
         [0078]    The control signal of the main controller  210  is transmitted through the gate signal lines  234  to the gate driver module  23 . The gate driver module  23  can be constructed to include a gate signal converter  232  performing gate signal processing on the control signal, an output driver  233  transmitting the processed signal to the full bridge resonant converter  22 , a gate controller  231  and so on. 
         [0079]    The gate controller  231  can be constructed to control the signal transmitting/receiving and processing operations in the gate driver module  23 . Thereby, the control signal from the main controller  210  is transmitted to corresponding parts, and a resultant power signal is transmitted and an induced magnetic field is stably generated. 
         [0080]    Next, in the charging operation, a signal requesting charge statue information is transmitted to the non-contact power receiving apparatus  30 , and the charge level of the non-contact power receiving apparatus  30  is adjusted based on the charge status information (adjustment of charging S 04 ). 
         [0081]    Then, after the full power transmission S 03 , the non-contact power receiving apparatus  30  charges the power, supplied through the rectifier block  33  and the smoothing filter block  34 , in the battery cell  35  through the charge IC block  36  and the PCM block  37  by the control of the device controller  390 . 
         [0082]    In response to this charging operation, the device controller  390  is inputted with information on the charge status through the charge IC block  36  and the PCM block  37 , and temporarily stores the charge status information in the device memory  391 . When the battery cell  35  is fully charged, the device controller  390  controls the charge IC block  36  to terminate the charging operation and controls to generate fully-charged status information from the secondary charge core  32  through the signal processing block  392 . Further, if the voltage of the charged battery cell  35  is lower than a predetermined reference voltage, the charging operation can be resumed. If it is discerned fully-charged status, the charging operation is terminated (No operation). 
         [0083]    Accordingly, in the adjustment of charging S 04 , the main controller  210  of the non-contact power transmission apparatus  10  requests status information on stepwise charge level from the non-contact power receiving apparatus  30 . As a response, the device controller  390  of the non-contact power receiving apparatus  30  transmits the charged status information to the non-contact power transmission apparatus  10  by load modulation. 
         [0084]    The charged status information from the non-contact power receiving apparatus is transmitted through the received signal processing module  24  to the main controller  210  connected to the received signal processing block  214 . The signal processing module  24  includes a received signal input  243  receiving a signal detected by load modulation, a received signal processor  242  converting the signal detected by load modulation and a received signal controller  241  controlling the operation of the received signal processing module  24 . 
         [0085]    According to this construction, the transmission information of the non-contact power receiving apparatus  30  received through load modulation is signal-converted in the received signal processing module  24  and is then transmitted to the main controller  210  through the received signal processing block  214 . The received signal processing module  24  may generally include a plurality of amplifiers, a low pass filter (LPF), an OR circuit and so on. 
         [0086]    When signals in response to load modulation are transmitted, a plurality of the received signal processors  242 , constructed in accordance with an embodiment, processes respective signals and transmits the processed signals to the main controller  210  through received signal lines  244 . 
         [0087]    Accordingly, the non-contact power transmission apparatus  10  requests the data information on the charge level of the non-contact power receiving apparatus  30 , particularly, via the gate driver module  23  and the primary charge core  13 . As a response, the non-contact power receiving apparatus  30  transmits the data information on the charge level of the battery cell  35 , received via the charge IC block  36  and the PCM block  37 , to the non-contact power transmission apparatus  10 . The data information is then transmitted to the main controller  210  through the primary charge core  13  and the received signal processing module  24 . 
         [0088]    As an alternative construction, when the voltage of the power signal received from non-contact power receiving apparatus  30  is determined to be lower or higher than a reference voltage, a corresponding signal can be transmitted to the non-contact power receiving apparatus  10  so as to adjust the voltage of the power signal. For example, as shown in  FIG. 18 , when the non-contact power receiving apparatus  30  moves to an outer area while being properly charged in the central area of the charge plate, the voltage of a received power signal is relatively lowered. To compensate for the lowered value, a voltage step-up request signal is transmitted to the non-contact power transmission apparatus  10 . Conversely, as shown in  FIG. 19 , when the non-contact power receiving apparatus  30  moves to the central area from the outer area of the charge plate, a relatively better power signal is received, in which the voltage of the power signal is relatively raised. Then, a voltage step-down request signal is transmitted to the non-contact power transmission apparatus  10  in order to stably receive power. 
         [0089]    Describing the adjustment of charging S 04  during the charging operation in accordance with an embodiment of the present invention, the non-contact power transmission apparatus  10  requests data on the charged status information (charge capacity information) from the non-contact power receiving apparatus  30 . As a response, the non-contact power receiving apparatus  30  transmits a signal including charge information data, such as the charge capacity data and the charged status information on the voltage of received power, and the non-contact power transmission apparatus receives the signal including the charge information data (step of receiving charge information data S 042 ). 
         [0090]    Data analysis and discerning is performed on the charged status information of the power signal transmitted from the non-contact power receiving apparatus (step of discerning power data S 043 ). A compensation frequency with respect to the voltage data on the power signal transmitted from the non-contact power receiving apparatus  30  is calculated and a compensated power signal having the compensation frequency is transmitted (step of transmitting compensated power signal S 044 ). 
         [0091]    In the above-mentioned example, the voltage of the received power signal acting as a reference in the non-contact power receiving apparatus  30  was 5V. In this case, it is assumed that the voltage 5V be stably received when the non-contact power receiving apparatus  30  does not move. However, when the voltage of the received power signal drops or rises in response to the movement of the non-contact power receiving apparatus  30 , the non-contact power transmission apparatus  10  modifies the frequency of the transmission power signal in order to compensate for a variation in the voltage of the received power signal, such that the non-contact power receiving apparatus  30  can receive the power signal at a stable voltage. 
         [0092]    Accordingly, a compensation frequency variation .DELTA.f of the transmitting power signal can be suitably determined based on the setting of the non-contact charging system A, the non-contact power transmission apparatus  10  and the non-contact power receiving apparatus  30 . For example, the compensation frequency variation .DELTA.f can be variously set with 10 Hz, 50 Hz, 100 Hz, 500 Hz, 1 KHz, 2 KHz, 5 KHz and so on. 
         [0093]    Based on data indicating the charge level of the non-contact power receiving apparatus  30 , the main controller  210  of the central control unit  21  displays the charge level or the state information using letters or a diagram on the LCD panel  153  through the signal output block  212  and also controls the charge status indicator LED module  154  to indicate the charging operation. Further, the charge status indicator LED module  154  is lighted in various fashions to indicate different statuses. For example, the charge status indicator LED module  154  may be turned off to indicate the termination of the charging operation, or flicker to indicate the charging operation. In addition, a green lamp of the charge status indicator LED module  154  may be turned on to indicate the fully-charged status, and a red lamp of the charge status indicator LED module  154  may be turned on to indicate an error caused by a foreign material, a unique ID error, and etc. 
         [0094]    When the non-contact power receiving apparatus  30  moves on or from the charge plate during the charging operation, the power signal transmitted from the non-contact power transmission apparatus  10  can be varied so as to optimize the charging efficiency of the non-contact power receiving apparatus  30 . 
         [0095]    Then, information on the fully-charged status is received from the non-contact power receiving apparatus  30 , the fully-charged status is displayed using the LCD panel  153  or the charge status indicator LED module  154 , corresponding to a charging block  14 , and the charging operation in the charging block  14  is terminated (fully-charged stage S 06 ). 
         [0096]    Preferably, the user can remove the fully-charged non-contact power receiving apparatus  30  from the stopped charging block  14 , and leave the charging block  14  in the standby mode until a starting signal is inputted. 
         [0097]    In the case of foreign material error (a PMD error) or ID error status, an error status is displayed and the operation is interrupted in order to ensure stability for the non-contact power transmission apparatus  10 , the non-contact power receiving apparatus  30 , a metallic object, or another electronic device. Accordingly, when the operation is interrupted due to an error, the process can preferably remain in the standby mode until a restarting signal is inputted from the user. 
         [0098]    Of course, in the case of the error status or the fully-charged status, a pulse signal can be periodically transmitted, the non-contact power receiving apparatus  30  can be detached or the foreign material can be removed so as to remove the error based on a signal caused by resultant load modulation. Then, the process can be converted into a normal standby mode. 
         [0099]    Furthermore, when the power signal is received in response to the request signal from the non-contact power transmission apparatus  10 , the device controller  390  of the non-contact power receiving apparatus  30  can control the data value of the voltage of the power signal to be transmitted to the non-contact power transmission apparatus  10 . 
         [0100]    A description will be given of charge-related procedures in the non-contact power receiving apparatus  30 . In the standby mode of the non-contact power receiving apparatus  30  for receiving a power signal, a call signal, transmitted together with an object detection signal from the primary charge core  13  of the non-contact power transmission apparatus  10 , is detected. Here, the call signal calls the unique ID value of the non-contact power receiving apparatus  30 . Then, a signal on the unique ID value of the non-contact power receiving apparatus  30  is transmitted to the non-contact power transmission apparatus (unique ID value transmitting step S 21 ). 
         [0101]    After the unique ID value transmitting step S 21 , the process is converted into a charge standby mode and a power signal received from the non-contact power transmission apparatus  10  is rectified and is then charged in the battery cell  35  (charging step S 22 ). 
         [0102]    Accordingly, a monitor module can be constructed to monitor the voltage of a power signal received from the non-contact power transmission apparatus  10  in response to a request or by the control of the device controller  390 . It is discerned whether or not the voltage of the received power signal is a reference voltage, if the voltage of the received power signal is below the reference voltage, a voltage adjustment signal is transmitted to request voltage step-up. Conversely, if the voltage of the received power signal is above the reference voltage, the voltage adjustment signal requests voltage step-down (voltage adjustment requesting step S 23 ). 
         [0103]    When a voltage received after the voltage adjustment requesting step S 23  is a reference voltage, a signal indicative of normal reception is transmitted (normal voltage signal transmitting step S 24 ). It is discerned whether or not the battery cell  35  is fully charged, and in the case of the fully-charged status, the charging operation is terminated (charging operation terminating step S 25 ). 
         [0104]    In the voltage adjustment requesting step S 23 , the level of the voltage of the received power signal can be discerned, and the charge level of the battery cell  35  can also be discerned. 
         [0105]    In the case of discerning the voltage of the received power signal, as shown in  FIG. 18  where the non-contact power receiving apparatus  30  is moved to the outer area from the central area of the non-contact power transmission apparatus  10 , received power is temporarily weakened since the non-contact power receiving apparatus  30  is located relatively in an outer position with respect to the primary charge core  13 . When a normally-received voltage is 5V, the low voltage monitor module  311  of the received power monitor module  31  detects a voltage 4.5V indicative of a voltage drop −0.5V. Accordingly, a signal requesting the stepping-up of transmission power (a power-up request signal) is transmitted to the non-contact power transmission apparatus  10 . 
         [0106]    Further, as shown in  FIG. 19 , the non-contact power receiving apparatus  30  is moved to the central area from the outer area of the non-contact power transmission apparatus  10 , where a stable voltage of about 5V is received. Here, received power is temporarily intensified since the non-contact power receiving apparatus  30  is located relatively in a central position with respect to the primary charge core  13 . Then, the low voltage monitor module  311  of the received power monitor module  31  detects a voltage 5.5V indicative of a voltage rise 0.5V. Accordingly, a signal requesting the stepping-down of transmission power (a power-down request signal) is transmitted to the non-contact power transmission apparatus  10 . 
         [0107]    As a result, the non-contact power transmission apparatus  10  can modify the frequency of the transmission power signal, such that the power signal can be received and charged at a more stable voltage. The stable reception of the voltage can be observed from graphs of  FIGS. 13 to 16 . 
         [0108]    Below, a detailed description will be given of the power control process in accordance with the adjusting of charging. 
         [0109]    As shown in  FIGS. 7 and 13  to  16 , a power signal transmitted from the primary charge core  13  of the non-contact power transmission apparatus  10  is received through the secondary charge core  32  of the non-contact power receiving apparatus  30 . Here, information on the intensity of the input voltage of the power signal is sent to the device controller  390 . 
         [0110]    If the voltage of the received power signal is detected as being transmitted at a stable voltage (e.g., 5V), the voltage can preferably be maintained to be uniform. Conversely, if the voltage of the received power signal is too low or high, information on voltage adjustment is transmitted by load modulation to the non-contact power transmission apparatus  10 , such that a uniform value of voltage can be received. When the voltage is adjusted to be uniform, the operation of the charge IC of the charge IC block  36  of the non-contact power receiving apparatus  30  is activated by the control of the device controller  390 , such that the power can be charged in the battery cell  35 . 
         [0111]    While the power transmitted from the non-contact power transmission apparatus  10  is charged in the battery cell  35  of the non-contact power receiving apparatus  30 , the PCM block  37  discerns whether or not the battery cell  35  is stabilized in order to ensure a stable charging operation. 
         [0112]    In the charging operation of the non-contact power charging system A including the non-contact power transmission apparatus  10  and the non-contact power receiving apparatus  30 , as shown in  FIGS. 18 and 19 , when the non-contact power receiving apparatus  30  moves on the charging plate of the non-contact power transmission apparatus  10 , the primary charge core  13  and the secondary charge core  32  are relocated, thereby dropping the receptibility of the power signal in the non-contact power receiving apparatus  30 . The location of the primary charge core  13  and the secondary charge core  32  becomes less efficient with the distance between the centers of the cores, such that induced electromotive force is rarely generated from the primary charge core  13  and the secondary charge core  32 . 
         [0113]    Accordingly, in the non-contact power charging system A of the present invention, when the voltage of the power signal received in the non-contact power receiving apparatus  30  placed on the charging block drops below or rises above the reference voltage, a compensation request signal is transmitted to the non-contact power transmission apparatus  10 , requesting the non-contact power transmission apparatus  10  to transmit a compensated power signal. 
         [0114]    For example, it is assumed that the reference voltage of the received power signal be 5V and a reference variation of the received voltage be +/−0.5V. As shown in  FIG. 18 , when the non-contact power receiving apparatus  30  is moved from the central portion to the outer portion, a voltage lower than 4.5V is received. Then, the control of the device controller  390  of the non-contact power receiving apparatus control unit  39  controls to transmit a voltage step-up request signal, such that the voltage is stepped up about 0.5V. Here, the secondary charge core  32  is controlled through the signal processing block  392  to transmit the voltage step-up request signal. 
         [0115]    Further, as shown in  FIG. 19 , when the non-contact power receiving apparatus  30  is moved from the outer portion to the central portion, a voltage higher than 5.5V is received. Then, the control of the device controller  390  of the non-contact power receiving apparatus control unit  39  controls to transmit a voltage step-down request signal, such that the voltage is stepped down about 0.5V. Here, the secondary charge core  32  is controlled through the signal processing block  392  to transmit the voltage step-down request signal. 
         [0116]    In response to the voltage step-up request signal or the voltage step-down request signal, the non-contact power transmission apparatus  10  transmits a compensated power signal, which is compensated for 0.5V. As an example of increasing the power signal transmitted from the non-contact power transmission apparatus  10 , it can be controlled to modify the oscillation frequency. 
         [0117]    As such, the power signal transmitted from the non-contact power transmission apparatus  10  is adjusted according to the location of the non-contact power receiving apparatus  30 . The charging efficiencies according to the replacement are illustrated in the graphs of  FIGS. 13 to 16 . 
         [0118]    In the test reported in  FIGS. 13 to 16 , the reference power in the secondary side of the non-contact power receiving apparatus  30  was on the order of 2.5 W. While the non-contact power receiving apparatus  30  was being moved horizontally and vertically moved on the charging plate of the non-contact power transmission apparatus  10  to a distance ranging from −7 mm to 7 mm, primary side power W at the non-contact power transmission apparatus  10 , secondary side power W at the non-contact power receiving apparatus  30  and the resultant efficiency (%) were measured and calculated. The efficiency (%) is produced by dividing the output power in the secondary side of the non-contact power receiving apparatus  30  with the input power in the primary side of the non-contact power transmission apparatus  10  as expressed in the formula: 
         [0000]      efficiency (%)=(secondary side power)/(primary side power)*100. 
         [0119]    In the meantime,  FIGS. 11 to 14  illustrate graphs related with power compensation tests, in which transmission power compensation was 0.5 W, and the secondary side power in the non-contact power receiving apparatus was in the range from 2 to 2.5 W. Here, the charging efficiency in the non-contact power transmission apparatus was obtained by changing the horizontal and vertical distance between the non-contact power transmission apparatus and the non-contact power receiving apparatus. Particularly.  FIGS. 11 and 12  illustrate cases in which power compensation according to frequency modification was not applied. Here, when the non-contact power receiving apparatus was moving horizontally or vertically with respect to the non-contact power transmission apparatus, the secondary side power of the non-contact power receiving apparatus decreased with the distance from the center, thereby lowering the charging efficiency. 
         [0120]    Comparatively,  FIG. 13  shows a graph resulting from horizontal movement and  FIG. 14  shows a graph resulting from vertical movement in the non-contact charging system A of the present invention. Information on the voltage variation of the received power in the non-contact power receiving apparatus was transmitted when the non-contact power receiving apparatus  30  was moving horizontally or vertically on the top surface of the charging block  14  of the non-contact battery pack as an example of the non-contact power transmission apparatus  10 . In response to this information, the non-contact power transmission apparatus  10  controlled (compensates for) power through frequency modification. Referring to the efficiencies in the graphs, power transmission was stable and thus power transmission efficiency was also good. 
         [0121]      FIG. 15  is an efficiency graph related with the horizontal movement, and  FIG. 16  is an efficiency graph related with the vertical movement. Referring to  FIGS. 15 and 16 , the charging efficiencies of compensated power transmission according to frequency modification (square-dotted profiles in the upper part, Power Control) were better than those without compensated power transmission according to frequency modification (circle-dotted profiles in the lower part, Fixed Power). 
         [0122]    Accordingly, the non-contact power charging system A including the non-contact power transmission apparatus  10  and the non-contact power receiving apparatus can stably transmit power without contacts. The non-contact power transmission apparatus  10  and the non-contact power receiving apparatus  30  of the non-contact power charging system A can be used as a stable system. 
         [0123]    When the user touches the non-contact power receiving apparatus  30  or the non-contact power transmission apparatus  10  shakes during the charging operation, the relative location of the primary charge core of the non-contact power transmission apparatus  10  and the secondary charge core of the non-contact power receiving apparatus  30  may be changed. However, the charging power compensation as described above makes it possible to charge the non-contact power receiving apparatus  30  with a stable voltage, such that the non-contact power receiving apparatus  30  can be charged in succession before being fully charged. 
         [0124]    As shown in  FIGS. 9 ,  10  and  17 , the non-contact power receiving apparatus  30  of the present invention also includes a shield member, which protects the non-contact power receiving apparatus  30  and the battery cell  35  from a magnetic field generated by the primary charge core  13  of the non-contact power transmission apparatus  10  and the secondary charge core  32  of the non-contact power receiving apparatus  30 . 
         [0125]    Firstly,  FIG. 9  is an exploded perspective view illustrating the construction of the non-contact power receiving apparatus  30  having a wireless power receiver module. The non-contact power receiving apparatus  30  is made of a coil, fine metal, a thin sheet of aluminum (e.g., an aluminum foil), and lithium ion or lithium polymer includes Aluminum in order to shield a magnetic field 100%, so that the cell can be free from the influence of the magnetic field. As a result, the cell can be charged and discharged for a predetermined cycle of 500 times or more. Here, the secondary charge core can have any core shapes. That is, the shape of the secondary charge core can include a quadrangle, a circle and an ellipse, and can be implemented as various types of cores such as a wound core and a spiral core. Accordingly, the non-contact power receiving apparatus  30  having a wireless power receiver module includes a wireless power receiver circuit  40  on one lateral side of the rechargeable battery cell  35  and a shied member  41  surrounding the wireless power receiver circuit  40 . The wireless power receiver circuit  40  is constructed including some parts of the non-contact power receiving apparatus  30 , such as the power receiver control unit  39  and the charge IC block  36 . 
         [0126]    Further, shielding plates  42 ,  43 ,  44 ,  45  and  46  are provided on the bottom and four side surfaces of the battery cell  35 , respectively, to shield a magnetic field from the primary charge core and the secondary charge core  32  so as to protect the battery cell  35  from the magnetic field. 
         [0127]    A total of five (5) shielding plates  42  to  46  is provided in total five directions including the four lateral directions and the downward direction of the battery cell  35  to completely shield the magnetic field from the primary charge core and the secondary charge core  32  so as to protect the battery cell  35  from being damaged by the magnetic field. Alternatively, a shielding plate can also be provided on the top surface of the rechargeable battery cell  35  if temperature rise due to the completely-enclosed structure of the battery cell  35  does not cause a trouble. 
         [0128]    The shielding plates  42  to  46  and the shielding member  41  can be formed as a thin sheet of metal such as Al, Cu or Ni alloy. 
         [0129]    Further, magnetic plates  48  are provided between the shielding plate  46 , which is placed under the battery cell  35 , and a charge receiver module  321  having the secondary charge core  32 . The magnetic plates  48  help the magnetic field be better induced to the secondary charge core  32 . The magnetic plates  48  may be constructed of amorphous ferrite, Mn—Zn (50 parts by weight: 50 parts by weight), Ni—Fe (80 parts by weight: 20 parts by weight), or fine metal (Fe—Si—Cu—Nb). 
         [0130]    The magnetic plates  48  include an upper magnetic plate  481 , placed between the shielding plate  46  and the charge receiver module  321 , and a lower magnetic plate, placed under the charge receiver module  321 . The lower magnetic plate  482  is formed with a lower plate through-hole  483 , which extends vertically through the lower magnetic plate  482 , particularly, the central portion of the lower magnetic plate  482 . The shape of the lower plate through-hole  483  may preferably conform to that of the secondary charge core  32 . Accordingly, 
         [0131]      FIG. 16  illustrates an example in which the lower plate through-hole  483  of the lower magnetic plate  482  was circular-shaped in order to conform to the circular shape of the secondary charge core  32 . Of course, when the core is quadrangular- or polygonal-shaped, the lower plate through-hole  483  may preferably be shaped in the same shape. The lower plate through-hole  483  configured as above helps induced electromotive force be better formed in the second charge core  32  in an induced magnetic field and signals be better transmitted. 
         [0132]    An insulating plate  47  is further provided between the battery cell  35  and the shielding plate  46  below the battery cell  35  to insulate the battery cell  35 . The insulating plate  47  is implemented with a mesh member or a thin film of Ni—Cu so as to prevent the heat of the shielding plate  46  from being conducted to the battery cell  35 . 
         [0133]      FIG. 10  shows another form of the magnetic field shielding member, which includes a battery cell case  35 ′ of aluminum encasing the battery cell  35 , a magnetic plate  48  of first Hanrim Postech electro-magnetic shield (HPES), which is placed between the battery cell case  35 ′ and the secondary charge core  32 , and a shielding mesh member  49  of second HPES, which is sandwiched between the magnetic plate  48  of first HPES and the battery cell case  35 ′. The magnetic plate  48  of first HPES and the shielding mesh member  49  of second HPES can have a composition the same as that of the above-described shielding member. 
         [0134]    The magnetic plate  48  of first HPES shields a majority of magnetic field, such that magnetic lines of force are bent by the magnetic plate  48  acting as a shielding plate, and thereby do not influence on the battery cell (see  FIG. 17 ). The magnetic lines of force generate heat in the top portion, and the heat is dissipated to the outside by the magnetic plate  48  made of metal. Further, the shielding mesh member  49  of second HPES is constructed with a mesh metal sheet coated with a coating agent composed of amorphous ferrite, Mn—Zn (50 parts by weight: 50 parts by weight), Ni—Fe (80 parts by weight: 20 parts by weight), or fine metal (Fe—Si—Cu—Nb). As such, the shielding mesh member  49  of second HPES serves to shield a remaining portion of the magnetic lines of force, which are not shielded by the magnetic plate  48  of first HPES. The mesh metal sheet of the shielding mesh member  49  of second HPES generate eddy current, which in turn protects the battery pack from the magnetic field generated by the primary charge core and the secondary charge core. According to tests, the magnetic plate  48  of first HPES shields about 90% and the shielding mesh member  49  shields about 10% of the magnetic field. 
         [0135]    500 times (500 cycles) of charging/discharging tests were performed on the non-contact power receiving apparatus  30  to which the magnetic plate  48  of first HPES and the shielding mesh member  49  of second HPES are applied. In  FIG. 17 , the reference was that the battery and the charging system were not charged and discharged without contacts but were charged and discharged via wires. When 500 times of charging and discharging were stably repeated, an efficiency curve of about 80% was set as reference efficiency segment (D). In  FIG. 17 , the graph shows the test results compared to the reference efficiency segment (D) of about 80%. Here, “N” indicates a resultant profile of a test using electrical contacts connected by wires without exposure to a magnetic field. The profile “N” of this test is positioned above the reference efficiency segment, thereby showing stable efficiency. 
         [0136]    Comparably, in  FIG. 17  indicates a profile of a test using the non-contact power receiving apparatus  30  of the invention, to which the magnetic plate  48  of first HPES, the shielding mesh member  49  and the like were applied. In this test profile, stable efficiency of 83.9% was observed at 500 times of charging and discharging. 
         [0137]    However, when second HPES was not applied (i.e., in a profile indicated with “B” in  FIG. 17 ), efficiency of 75.3% was observed at 460 times of charging and discharging. When neither first HPES nor second HPES was applied (i.e., in a profile indicated with “C” in  FIG. 17 ), poor efficiency of 74.5% was observed at 340 times of charging and discharging, which fall short of the reference 500 times. It can be understood that the test of the invention has much better efficiency. 
         [0138]    While the present invention has been described with reference to the particular illustrative embodiments and the accompanying drawings, it is not to be limited thereto. Accordingly, the foregoing embodiments can be suitably modified and altered, and such applications fall within the scope and spirit of the present invention that shall be defined by the appended claims.

Technology Classification (CPC): 7