Patent Publication Number: US-2012029728-A1

Title: Charging device for vehicle and vehicle

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a charging device for a vehicle and also to a vehicle. 
     With the popularization of an electric vehicle and a plug-in hybrid vehicle, a charging facility for the vehicles is increasingly needed. The Japanese Patent Application Publication No. 2010-93891 discloses a plug-in hybrid vehicle having a first charging line for charging a battery from an external power source through a charging cable, a first supply line for supplying power from the battery through a vehicle outlet and a second supply line for supplying power through the charging cable and the vehicle outlet. According to the Publication, a state of connection of the charging cable with the vehicle is detected and either of the first and second supply lines is selected according to the detected state of connection for supplying power through the selected supply line and the vehicle outlet. 
     It has been known that control pilot (CPLT) signals are transmitted between a charging device and a plug-in hybrid vehicle through a charging cable, and the charging device and the plug-in hybrid vehicle detect such CPLT signals, so that the state of the vehicle is monitored and charging for the vehicle is controlled, accordingly. 
     In the plug-in hybrid vehicle in the cited Publication, a proximity detection (PD) signal is used for detecting the state of connection between a plug of the charging cable and a receptacle of the vehicle. CPLT signal detecting circuits for detecting CPLT signals are provided in the charging device and the plug-in hybrid vehicle, respectively, and a PD signal detecting circuit is provided in the plug-in hybrid vehicle. 
     On the other hand, it has been proposed that communication between the charging device and the plug-in hybrid vehicle should be performed by power line communication (PLC). However, if the communication between the vehicle having the CPLT signal detecting circuit and the PD signal detecting circuit and the charging device having the CPLT signal detecting circuit is performed by PLC, there is a fear that the CPLT signal detecting circuit and the PD signal detecting circuit may malfunction due to the PLC signals transmitted through the power line or through a ground line. 
     The present invention is directed to prevent the CPLT signal detecting circuits provided in the charging device and the vehicle from malfunctioning due to the influence of PLC. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, a charging device for a vehicle includes a device-side power line communication modem, a device-side control pilot signal generating circuit, a device-side control pilot signal detecting circuit and a device-side low-pass filter. A charging cable includes a power line, a ground line and a signal line. Power is supplied from the charging device to the vehicle through the power line. The device-side power line communication modem is used for power line communication between the vehicle and the charging device. The device-side control pilot signal generating circuit is used for generating control pilot signals. The device-side control pilot signal detecting circuit is used for detecting the control pilot signals transmitted from the vehicle through the signal line to determine whether or not the vehicle is ready for charging and whether or not the charging is completed. The device-side low-pass filter is connected to an input of the device-side control pilot signal detecting circuit and has such a frequency characteristics that allows the control pilot signals to pass through the device-side low-pass filter but removes signals having frequencies in a frequency band used for power line communication. 
     A vehicle has a receptacle being connected to a plug of a charging cable. A charging cable includes a ground line, a power line and a signal line. Power is supplied from a charging device to the vehicle through the power line. The vehicle includes a vehicle-side power line communication modem, a vehicle-side proximity detection signal circuit, a first vehicle-side low-pass filter, a vehicle-side control pilot signal detecting circuit and a second vehicle-side low-pass filter. The vehicle-side power line communication modem is used for power line communication between the charging device and the vehicle. The vehicle-side proximity detection signal circuit is used for detecting signals indicative of a state of connection between the receptacle of the vehicle and the plug of the charging cable. The first vehicle-side low-pass filter is connected to an input of the vehicle-side proximity detection signal circuit and has such a frequency characteristics that removes signals having frequencies in a frequency band used for power line communication. The vehicle-side control pilot signal detecting circuit is used for detecting the control pilot signals transmitted from the charging device through the signal line. The second vehicle-side low-pass filter is connected to an input of the vehicle-side control pilot signal detecting circuit and has such a frequency characteristics that allows the control pilot signals to pass through the second vehicle-side low-pass filter but removes signals having frequencies in a frequency band used for power line communication. 
     A charging device for a vehicle includes a device-side power line communication modem, a device-side control pilot signal generating circuit and a device-side control pilot signal detecting circuit. The charging cable includes the power line, a ground line and a signal line. Power is supplied from the charging device to the vehicle through the power line. The vehicle includes a vehicle-side power line communication modem. The device-side power line communication modem is used for power line communication between the vehicle and the charging device. The device-side control pilot signal generating circuit is used for generating control pilot signals. The device-side control pilot signal detecting circuit is used for detecting the control pilot signals transmitted from the vehicle through the signal line. Detection for a control pilot signal is performed in the device-side control pilot signal detecting circuit when there is no power line communication between the device-side power line communication modem and the vehicle-side power line communication modem. 
     A vehicle has a receptacle being connected to a plug of a charging cable. The charging cable includes a ground line, a power line and a signal line. Power is supplied from a charging device to the vehicle through the power line. The charging device includes a device-side power line communication modem. The vehicle includes a vehicle-side power line communication modem, a vehicle-side proximity detection signal circuit and a vehicle-side control pilot signal detecting circuit. The vehicle-side power line communication modem is used for power line communication between the charging device and the vehicle. The vehicle-side proximity detection signal circuit is used for detecting signals indicative of a state of connection between the receptacle and the plug. Detection for a proximity detection signal is performed in the vehicle-side proximity detection signal circuit when there is no power line communication between the vehicle-side power line communication modem and the device-side power line communication modem. The vehicle-side control pilot signal detecting circuit is used for detecting control pilot signals transmitted from the charging device through the signal line. Detection for a control pilot signal is performed in the vehicle-side control pilot signal detecting circuit when there is no power line communication between the vehicle-side power line communication modem and the device-side power line communication modem. 
     Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features of the present invention that are believed to be novel are set forth with particularity in the appended claims. The invention together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which: 
         FIG. 1  is a configuration diagram showing a charging device and a vehicle according to a first preferred embodiment of the present invention; 
         FIG. 2  is a configuration diagram showing a CPLT signal control circuit and a PD signal detecting circuit in the charging device and the vehicle of  FIG. 1 ; 
         FIG. 3  is an illustrative view showing a low-pass filter (LPF) of  FIG. 1 ; 
         FIG. 4  is a configuration diagram showing a charging device and a vehicle according to a second preferred embodiment of the present invention; 
         FIG. 5  is a configuration diagram showing a charging device and a vehicle according to a third preferred embodiment of the present invention; 
         FIG. 6A  is a flowchart showing operation of the CPLT signal detecting circuit in the charging device of  FIG. 5 ; and 
         FIG. 6B  is a flowchart showing operations of the PD signal detecting circuit and the CPLT signal detecting circuit in the vehicle of  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following will describe a first preferred embodiment of the present invention with reference to  FIGS. 1 through 3 .  FIG. 1  shows a charging device  11  and a vehicle  12  according to the first preferred embodiment of the present invention, in which alternating-current (AC) power of the charging device  11  is supplied to the vehicle  12 . The charging device  11  has a relay  14 , a control pilot (CPLT) signal generating circuit  15  serving as a device-side control pilot signal generating circuit, a CPLT signal detecting circuit  16  serving as a device-side control pilot signal detecting circuit, a low-pass filter (LPF)  17  serving as a device-side low-pass filter, a power line communication (PLC) modem  18  serving as a device-side power line communication modem and a band-pass (BPF) filter  19 . 
     The relay  14  is used for supplying AC power from an AC power source  13  to the vehicle  12  through power lines  23 ,  24 , and a charging cable  20  includes the power lines  23 ,  24 , a signal line  25  and a ground line  26 . The CPLT signal generating circuit  15  generates CPLT signals having a square-wave pulse. The CPLT signal generating circuit  15  is also operable to modify the pulse width of ON-pulse of the CPLT signal thereby to report to the vehicle  12  the amount of available power for the vehicle  12 . The CPLT signals are transmitted to the vehicle  12  through the signal line (pilot line)  25 . 
     The CPLT signal detecting circuit  16  detects the voltage on the signal line  25  thereby to determine whether or not the vehicle  12  is ready for charging and also whether or not the charging is completed. The PLC modem  18  is connected in the ground line  26  for transmitting PLC signals to a PLC modem  37  serving as a vehicle-side power line communication modem provided in the vehicle  12 . 
     The LPF  17  has such a frequency characteristics that allows the CPLT signals to pass therethrough but removes signals having frequencies greater than a predetermined level that is the lower limit of a frequency band used for PLC. 
     The CPLT signal detecting circuit  16  detects a voltage level of the CPLT signals from which signals in the frequency band used for PLC are removed by the LPF  17 . The BPF  19  is connected between the power lines  23 ,  24  and the ground line  26  for allowing only signals for PLC to pass therethrough. 
     The vehicle  12  has a receptacle (connector)  22 , a charge control device  27 , a charger  28  and a chargeable battery  29 . The receptacle  22  of the vehicle  12  is connected to a plug  21  of the charging cable  20  for supplying AC power from the charging device  11  to the vehicle  12 . 
     The charge control device  27  includes a CPLT signal control circuit  31 , a CPLT signal detecting circuit  32  serving as a vehicle-side control pilot signal detecting circuit, a LPF  33  serving as a first vehicle-side low-pass filter, a LPF  35  serving as a second vehicle-side low-pass filter, a PD signal detecting circuit  34  serving as a vehicle-side proximity detection signal detecting circuit, a BPF  36  and a PLC modem  37 . 
     The CPLT signal control circuit  31  controls the voltage level of the CPLT signals transmitted through the signal line  25 . The CPLT signal detecting circuit  32  detects a voltage level and the pulse width of the ON-pulse of CPLT signals having removed therefrom by the LPF  33  signals in the frequency band for PLC. The BPF  36  is connected between the power lines  23 ,  24  and the ground line  26  for allowing only signals for PLC to pass therethrough. 
     A PD circuit  38  serving as a vehicle-side proximity detection circuit is connected across the plug  21 , the receptacle  22  and the charge control device  27  for generating PD signals indicative of the state of connection between the plug  21  and the receptacle  22 . The LPF  35  has frequency characteristics that allows the PD signals to pass through the LPF  35 , but removes therefrom signals having a frequency greater than a predetermined value that is lower limit in the frequency band for PLC. 
     The PD signal detecting circuit  34  detects a voltage level of PD signals having removed therefrom by the LPF  35  signals in the frequency band for PLC. The PLC modem  37  is connected in the ground line  26  for PLC with the PLC modem  18  provided in the charging device  11  through the ground line  26 . 
       FIG. 2  shows an example of the CPLT signal generating circuit  15 , the CPLT signal control circuit  31  and the PD circuit  38 . The CPLT signal generating circuit  15  of the charging device  11  includes an oscillator  41  which generates signals having a square-wave pulse and a resistor R 1  which is connected at one end thereof to the oscillator  41  and at the other end thereof to the signal line  25 . 
     The PLC modem  18  is connected in series in the ground line  26  through a coupling transformer  42  having primary and secondary windings. The CPLT signal control circuit  31  in the vehicle  12  is used for changing the voltage level of CPLT signals. The CPLT signal control circuit  31  includes a diode D 1  connected in the signal line  25 , resistors R 2 , R 3  connected at one end thereof to the cathode of the diode D 1  and a switch SW 1  connected at one end thereof in series to the resistor R 3 . The other ends of the resistor R 2  and the switch SW 1  are grounded to the body of the vehicle  12 . A transistor may be used as the switch SW 1  for changing the voltage level of CPLT signals by switching the transistor by any central processing unit (CPU) (not shown). 
     When the switch SW 1  is in ON-state, the level of the output voltage of the CPLT signal control circuit  31  is determined by the output voltage of the oscillator  41  in the CPLT signal generating circuit  15  as divided by the total resistance of the resistor R 1  of the CPLT signal generating circuit  15  and the parallel resistors R 2 , R 3  of the CPLT signal control circuit  31 . 
     When the switch SW 1  is in OFF-state, the level of the output voltage of the CPLT signal control circuit  31  is determined by the output voltage of the oscillator  41  as divided by the total resistance of the resistors R 1 , R 2 . 
     Thus, the voltage level of the CPLT signals is changed by turning on and off the switch SW 1 , so that the charging device  11  is notified of the completion of preparation or the completion of charging of the vehicle  12 . 
     The CPLT signal detecting circuit  32  detects the voltage level of CPLT signals having removed therefrom by the LPF  33  signals in the frequency band for PLC, so that the CPLT signal detecting circuit  32  is prevented from malfunctioning. 
     The PD circuit  38  is connected across the plug  21 , the receptacle  22  and the charge control device  27  for generating signals indicative of the connection between the plug  21  and the receptacle  22 . 
     Specifically, the resistor R 4  connected at one end thereof to the ground line  26 , the switch SW 2  connected in parallel to the resistor R 4 , and a resistor R 5  connected in series to the resistor R 4  are provided as a part of the PD circuit  38 . The switch SW 2  is a mechanical or electrical switch which is turned on when the plug  21  is inserted firmly into the receptacle  22  to be in locked state, and turned off otherwise. 
     A resistor R 6  is provided in the receptacle  22  as a part of the PD circuit  38 . One end the resistor R 6  is connected to the connecting point of the receptacle  22  indicated by arrow shown in the PD circuit  38  of  FIG. 2 . When the receptacle  22  and the plug  21  are connected to each other, the resistors R 5 , R 6  are connected to each other. The other end of the resistor R 6  is connected to the ground line  26  on the plug  21  side through the connecting points of the receptacle  22  and the plug  21 . 
     A resistor R 7  connected at one end thereof to a power supply voltage Vd is provided in the charge control device  27  as a part of the PD circuit  38 . The other end of the resistor R 7  is connected to one end of the resistor R 6  that is connected to the connecting point of the receptacle  22 . 
     When the plug  21  is inserted in the receptacle  22  but insufficiently connected to the receptacle  22 , the switch SW 2  is in OFF state. In this case, if two pairs of the connecting points indicated by arrows in the plug  21  and the receptacle  22  of  FIG. 2  are electrically connected to each other, the total resistance of the resistors R 4  through R 6  is determined by the resistance of the resistor R 6  and the series resistors R 4 , R 5  connected in parallel to the resistor R 6 . 
     When the plug  21  is inserted firmly in the receptacle  22  to be in locked state, the switch SW 2  is in ON state. In this case, since the resistor R 4  is shorted, the total resistance of the resistors R 4  through R 6  is determined by the parallel resistors R 5 , R 6 . 
     Depending on the state of connection between the plug  21  and the receptacle  22 , the above total resistance is varied, and the voltage at the connection point between the resistors R 6 , R 7 , or the voltage level of PD signal that is the output signal of the PD circuit  38 , is varied, accordingly. 
     When the plug  21  and the receptacle  22  are not connected, the resistors R 4 , R 5  are separated from the resistor R 6 , so that a voltage obtained by dividing the power supply voltage Vd by the resistors R 6 , R 7  is outputted to the PD signal detecting circuit  34 . 
     Thus, detecting the voltage level of the output signal of the PD circuit  38  by the PD signal detecting circuit  34 , state of connection between the plug  21  and the receptacle  22 , i.e. whether the plug  21  and the receptacle  22  are connected firmly to each other to be in locked state, connected only insufficiently, or not connected. 
     The PD signal detecting circuit  34  that detects the voltage level of the PD signals having removed therefrom signals in the frequency band for PLC is prevented from malfunctioning. 
       FIG. 3  shows in detail the LPF  17 ,  33  or  35 . The LPF  17  includes a resistor R 11  and a capacitor C 11 . The resistor R 11  receives at one end thereof CPLT signals or RD signals and is connected at the other end thereof to one end of the capacitor C 11  and the input terminal of the CPLT signal detecting circuits  16 ,  32  or the PD signal detecting circuit  34 . The other end of the capacitor C 11  is grounded. 
     The resistance of the resistor R 11  and the capacitance of the capacitor C 11  are set such that the LPF  17  has frequency characteristics that remove signals in a frequency band for PLC (for example more than 100 kHz) and allow signals in the frequency band for CPLT (for example a few kHz) to pass through the LPF  17 . The LPF  17  may have only frequency characteristics that remove signals in a frequency band for PLC. 
     According to the first preferred embodiment of the present invention, when communication between the charging device  11  and the vehicle  12  is performed by PLC, and CPLT signals are transmitted and received through the signal line  25 , the CPLT signal detecting circuits  16 ,  32  and the PD signal detecting circuit  34  are prevented from malfunctioning by input of PLC signals. 
     Detection of the state of connection and charging between the plug  21  and the receptacle  22  by using CPLT and PD signals helps to improve the safety of the vehicle user during charging. Furthermore, the use of PLC ensures high-speed and secure data communication between the charging device  11  and the vehicle  12 . 
     The following will describe a second preferred embodiment of the present invention.  FIG. 4  shows a configuration diagram of the charging device  51  and a vehicle  52  according to the second preferred embodiment of the present invention. In  FIG. 4 , the same reference numerals denote the circuits substantially identical to the counterparts in  FIGS. 1 ,  2  and, therefore, the description thereof will be omitted. According to the second preferred embodiment, the PLC modems  18 ,  37  are connected between the ground line  26  and the power line  23  through the respective coupling transformers  42 ,  43 . 
     One end of the primary wiring of the coupling transformer  42  of the charging device  51  is connected to the ground line  26 , and the other end of the primary wiring is connected to the power line  23  through the capacitor C 1 , and the secondary wiring is connected to the PLC modem  18 . Thus, the capacitor C 1  is connected between the power line  23  and the ground line  26 . 
     One end of the primary wiring of the coupling transformer  43  of the vehicle  52  is connected to the ground line  26 , and the other end of the primary wiring is connected to the power line  23  through the capacitor C 2 , and the secondary wiring is connected to the PLC modem  37 . Thus, the capacitor C 2  is connected between the power line  23  and the ground line  26 . 
     In connecting the PLC modems  18 ,  37  between the power line  23  and the ground line  26 , the LPF  17  is connected to the input of the CPLT signal detecting circuit  16  of the charging device  51 , the LPF  33  is connected to the input of the CPLT signal detecting circuit  32  of the vehicle  52 , and the LPF  35  is connected to the input of the PD signal detecting circuit  34 . By so doing, the CPLT signal detecting circuits  16 ,  32  and PD signal detecting circuit  34  are prevented from malfunctioning due to the influence of PLC signals. 
     The following will describe a third preferred embodiment of the present invention.  FIG. 5  shows a configuration diagram of a charging device  61  and a vehicle  62  according to the third preferred embodiment of the present invention. According to the third preferred embodiment of the present invention, detection for CPLT and PD signals is performed when a PLC modem  63  serving as a device-side power line communication modem transmits and receives no signal. 
     In  FIG. 5 , the same reference numerals denote the circuits substantially identical to the counterparts in  FIG. 1  and, therefore, the description thereof will be omitted. The PLC modem  63  of the charging device  61  is connected in the ground line  26  for generating to the CPLT signal detecting circuit  16  signals that are indicative of whether or not it is time to transmit and receive PLC signals. 
     The CPLT signal detecting circuit  16  of the charging device  61  is operable to determine whether or not a signal is received that is indicative that it is not time to transmit and receive PLC signal. If NO (or if it is not time to transmit PLC signals), the detection for CPLT signals is performed, and if YES (or if it is time to transmit PLC signals), no detection for CPLT signals is performed. 
     The PLC modem  64  of the vehicle  62  serving as a vehicle-side power line communication modem generates to the CPLT signal detecting circuit  32  and the PD signal detecting circuit  34  signal that is indicative that it is not time to transmit and receive PLC signals. 
     The CPLT signal detecting circuit  32  determines whether or not a signal indicative that it is not time to transmit or receive PLC signals. If YES (or if it is not time to transmit PCL signals), the detection for CPLT signals is performed, and if NO (or if it is time to transmit PCL signal), no detection for CPLT signal is performed. 
     The PD signal detecting circuit  34  determines whether or not signal indicative that it is not time to transmit or receive the PLC signal. If YES (or if it is not time to transmit PLC signal), the detection for CPLT signals is performed, and if NO (or if it is time to transmit PLC signal), no detection for PD signals is performed. 
       FIGS. 6A ,  6 B are flowcharts showing the operations of the CPLT signal detecting circuits  16 ,  32  and the PD signal detecting circuit  34 . Procedures according to the flowcharts are performed by any hardware or CPU provided in the charging device  61  or the vehicle  62 . 
     Referring to  FIG. 6A , the following will describe the operation of the CPLT signal detecting circuit  16  of the charging device  61 . At step S 11 , it is determined whether or not it is time to detect CPLT signal. If NO at step  11 , step S 11  is repeated. 
     If YES at step  11 , it is determined at step S 12  whether or not PLC signal serving as carrier signal is detected in the ground line or the power line serving as a communication line to which the PLC modem  63  is connected. Detection for PLC signal, including PLC signal transmitted by the device itself, is performed. 
     If YES at step S 12 , the detection for the PLC signal at step S 12  is repeated. If NO at step S 12 , detection for CPLT signal is performed at step S 13 . 
     Referring to  FIG. 6B , the following will describe the operations of the PD signal detecting circuit  34  and the CPLT signal detecting circuit  32  provided in the vehicle  62 . At step S 21 , it is determined whether or not it is time to detect PD or CPLT signal. If NO at step  21 , step S 21  is repeated. 
     If YES at step S 21 , it is determined at step S 22  whether or not PLC signal serving as carrier signal is detected. If YES at step S 22 , step S 22  is repeated. 
     If NO at step S 22 , detection for PD or CPLT signal is performed at step S 23 . According to the third preferred embodiment of the present invention, the detection for PD and CPLT signal may be performed without any influence of PLC signal. Therefore, the PD signal detecting circuit  34  and the CPLT signal detecting circuits  16 ,  32  are prevented from malfunctioning due to the PLC signal. 
     In the above-described preferred embodiments of the present invention, AC power is supplied to the vehicle. Alternatively, direct-current (DC) power may be supplied to the vehicle.