METHOD AND ADAPTER FOR COMMUNICATION WITH A CHARGING CABLE OF A BATTERY-POWERED ELECTRIC VEHICLE

Abstract

A method for communication between an external computer and a charging cable with an in-cable control box for charging battery-powered electric vehicles includes providing the charging cable with a data line for communication with the vehicle. A hardware interface between control box and computer allows access to the data line through the computer. Data for the control box is sent from the computer to the hardware interface, modulated by the hardware interface to the signal of the data line, and transmitted to the control box. Data for the computer is sent from the control box through the signal of the data line, converted by the hardware interface, and sent to the computer. The data is sent from control box to computer by modification of the pulse width of the signal of the data line and sent to the hardware interface, which forwards the data to the computer.

Claims

1. A method for communication between an external computer and a charging cable having an in-cable control box for charging battery-powered electric vehicles, the method comprising the following steps: providing the charging cable with a data line for communicating with the vehicle; using a hardware interface between the in-cable control box of the charging cable and the computer to allow access to the data line through the computer; sending data for the in-cable control box of the charging cable from the computer to the hardware interface, modulated to a signal of the data line by the hardware interface and transmitting the data to the in-cable control box of the charging cable, while sending data for the computer from the in-cable control box of the charging cable through the signal of the data line being converted by the hardware interface and sent to the computer; and sending the data from the in-cable control box of the charging cable from the in-cable control box of the charging cable to the computer, modulated by modifying a pulse width of the signal of the data line and sent to the hardware interface which forwards the data to the computer.

2. The method according to claim 1, which further comprises exchanging data between the hardware interface and the computer by using a serial interface, and converting the data sent from the hardware interface to a serial protocol.

3. The method according to claim 1, which further comprises using the hardware interface to modulate the data sent from the computer to the in-cable control box of the charging cable by modifying a voltage level of the signal of the data line.

4. The method according to claim 3, which further comprises modifying the voltage level by amplitude shift keying.

5. The method according to claim 1, which further comprises performing a calculation for converting data sent from the in-cable control box of the charging cable to the computer by the hardware interface by measuring the pulse width and time sequence of the signal of the data line.

6. The method according to claim 3, which further comprises simultaneously modulating the pulse width of the signal of the data line and modifying the voltage level to make the data exchange bidirectional and duplex-capable.

7. The method according to claim 3, which further comprises using a plurality of different pulse widths for modulating the pulse width of the signal of the data line, and using a plurality of different voltage levels for modifying the voltage level in order to increase a data transfer rate of the data exchange.

8. The method according to claim 3, which further comprises modifying only a negative part of the voltage level for sending data from the computer to the in-cable control box of the charging cable, in order to allow a data exchange between the in-cable control box of the charging cable and the computer in parallel with a process of charging the battery-powered electric vehicle through the charging cable.

9. The method according to claim 8, which further comprises time-delaying the modification of the negative voltage level to permit the modified voltage levels to fit into a low phase of a PWM signal, thereby increasing a data transfer rate of the data exchange.

10. The method according to claim 1, which further comprises including data for fault diagnosis and operating statistics in the data sent from the in-cable control box of the charging cable to the computer.

11. The method according to claim 1, which further comprises including software updates for the in-cable control box of the charging cable in the data sent from the computer to the in-cable control box of the charging cable.

12. An adapter implementing a hardware interface for communication between an external computer and a charging cable having an in-cable control box for charging battery-powered electric vehicles according to claim 1, the adapter comprising: a vehicle connector according to IEC 62196-2 being plugged into a vehicle coupling of the in-cable control box according to IEC 62196-2; a USB connector connecting the adapter to the computer; and a microcontroller configured to carry out a data exchange between the computer and the in-cable control box of the charging cable through a serial interface.

13. The adapter according to claim 12, wherein said serial interface is a USB interface.

14. The adapter according to claim 12, which further comprises a further vehicle coupling connected to the battery-powered electric vehicle for charging the battery-powered electric vehicle simultaneously with data exchange with the computer through the interface.

15. The adapter according to claim 12, wherein the adapter is configured to use negative and positive voltage levels with amplitude values that cannot be generated on the data line by the battery-powered electric vehicle, in order to make contact with the in-cable control box.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0026] FIG. 1 is a block diagram illustrating a charging process of a battery-powered electric vehicle;

[0027] FIG. 2 is a block diagram illustrating communication according to the invention by using a charging cable;

[0028] FIG. 3 is a diagram illustrating a functional structure of an adapter, with a pin assignment;

[0029] FIG. 4 is a block diagram illustrating simultaneous implementation according to the invention, of communication with the charging cable and charging of the battery-powered electric vehicle;

[0030] FIG. 5 is a diagrammatic, perspective view of a structural organization of the adapter with a housing;

[0031] FIG. 6 is a circuit diagram of a system according to the invention, in a first embodiment;

[0032] FIG. 7 is a diagram illustrating modulation of the data on a signal line according to the invention, in a first embodiment;

[0033] FIG. 8 is a circuit diagram of the system according to the invention, in a second embodiment;

[0034] FIG. 9 is a circuit diagram of the system according to the invention, in a third embodiment;

[0035] FIG. 10 is a diagram illustrating modulation of the data on the signal line according to the invention, in a third embodiment; and

[0036] FIG. 11 is a diagram illustrating modulation of the data on the signal line according to the invention, in a fourth embodiment.

DETAILED DESCRIPTION OF THE INVENTION

[0037] Communication between a charging cable or IC-CPD 3 and a battery-powered electric vehicle 6 is regulated according to the IEC-61851 and IEC-62752 standards. This provides, among other things, that the charging cable, i.e. the IC-CPD 3, has a PWM generator with 1 kOhm internal resistance, the fundamental frequency of the pulse width modulated signal 13 (PWM signal) is 1 kHz, information sent from the charging cable (IC-CPD 3) to the battery-powered electric vehicle 6 is transmitted by changing the pulse width, and information sent from the battery-powered electric vehicle 6 to the charging cable (IC-CPD 3) is transmitted by changing the positive signal level.

[0038] Referring now to the figures of the drawings in detail and first, particularly, to FIG. 1 thereof, there is seen an example of a structural organization of the battery-powered electric vehicle 6, a charging cable, and a power grid 1 that provides a charging current 2. A standard charging cable has no additional interfaces for fault diagnostics or software updates. Additional wireless interfaces that would be possible include Bluetooth, WLAN, and Zigbee. Possible wired interfaces include USB 9, RS232 or Ethernet (TCP/IP). All these interfaces share the drawback that additional manufacturing costs for the (externally accessible) interface are incurred and the product becomes accordingly more expensive. In addition, a wired interface must be sealed.

[0039] The present invention avoids these drawbacks. Communication for fault diagnosis, information exchange and software update may take place without additional hardware in the charging cable.

[0040] Based on the requirements of IEC-61851 and IEC-62752, several methods have been developed for communication with the charging cable.

[0041] In order to implement these methods, a special communication adapter 7 is connected between the charging cable 2 and a computer in the form of a diagnostic PC 8. FIG. 2 shows the necessary structural organization between the charging cable and the diagnostic PC 8, through the use of which data 4 for fault diagnosis and/or firmware updates of the IC-CPD 3 may be replaced. FIG. 3 schematically shows the organization for this purpose. The drawing shows how the CP signal 4 is detected and evaluated by using the adapter 7. Also shown are pins of a corresponding vehicle connector 10 for Mode 2, which are used by the adapter 7.

[0042] In addition, FIG. 5 shows the structural organization of an adapter 7 integrated into a vehicle connector 10 according to IEC 62196 Type 2, for connecting to a vehicle coupling 5 of the IC-CPD 3, as well as the structural organization of a type A USB connector 9 for connecting to the diagnostic computer 8, together with the housing thereof.

[0043] The adapter 7 has a microcontroller that controls the data transfer between the IC-CPD 3 and the diagnostic PC 8. This adapter fundamentally measures the pulse width of the PWM signal 13 on a CP signal line 11. The adapter calculates the byte sent by the charging cable from the time sequence of the measured pulse widths, and sends it on to the diagnostic PC 8 through a standard interface (UART). Furthermore, the communication adapter 7 receives information from the diagnostic PC 8 at the UART interface and forwards it to the charging cable by modifying the voltage levels of the data signal 4.

[0044] In order to establish a communication connection to the charging cable, the communication adapter brings the CP signal 4 to 12 V for 50 ms. Then it is checked whether or not the charging cable is in the communication mode (i.e. whether the PWM signal 13 is on). If not, the process is repeated with +12 V. If no communication with the charging cable is established after 1 second, the process is aborted.

[0045] The 12 V level was chosen because an electric vehicle (EV) cannot produce it. Thus, it may safely be distinguished from the electric vehicle. If the IC-CPD is in a fault state F (CP signal 12 V), the communication adapter changes this level to +12 V. The electric vehicle also cannot produce this level.

[0046] The schematic structure of the overall system, with the relevant components of the adapter 7, the diagnostic PC 8 and the IC-CPD 3, is disclosed in the form of a circuit diagram in FIG. 6. FIG. 6 shows a first preferred embodiment in which the diagnostic PC 8 is connected directly to the vehicle coupling 5 of the IC-CPD 3 through the adapter 7. In this case, during communication, the charging cable cannot be used simultaneously for charging the battery-powered electric vehicle 6, because the output of the IC-CPD 5 is occupied by the plug 10 of the adapter 7.

[0047] During the connection setup, the IC-CPD 5 applies +12 V (state A) to the CP signal 4. As soon as the communication adapter 7 has received the command to establish communication from the diagnostic PC 8, it switches the CP signal 4 to 12 V for 50 ms with the signal Act-12 V and t1. When the IC-CPD 3 detects this, the PWM signal 13 is enabled. The low bit and high bit are each assigned a voltage level for data exchange from the communication adapter 7 to the IC-CPD 3. The low bit and high bit each have a pulse width assigned to the CP signal 4 for data exchange from the IC-CPD 3 to the communication adapter 7. Since the PWM frequency is set to 1 kHz in the IEC-61851 standard and only one bit is transmitted per PWM pulse, the achieved transmission rate is only 111 bytes/sec (8N1).

[0048] FIG. 7 shows the CP signal during connection setup and communication. At the time t1, the communication adapter 7 sets the CP signal 4 to 12 V and instructs the IC-CPD 3 to establish the communication connection. At a time t2, the communication adapter 7 switches the 12 V off again. Thus, the PWM signal 13 (pulse width idle), which the IC-CPD 3 has now switched on, may take precedence. At a time t3, the communication adapter 7 begins sending a byte to the IC-CPD 3 by using amplitude shift keying 12. First, a start bit (level high) is transmitted, followed by 8 data bits (MSB-first 00110010t>032). At a time t4, the transmission is completed. At a time t5, the IC-CPD 3 begins sending a byte to the communication adapter 7. First a start bit (300 s wide) is sent, followed by 8 data bits MSB-first 11001101t>0cd.

[0049] Since sending and receiving refer to different aspects of the CP signal 4, the transmission is fully duplex-capable. Since communication from the IC-CPD 3 to the diagnostic PC 8 is done by PWM, while communication in the reverse direction is done by amplitude shift keying 12, both are possible at the same time. In other words, sending and receiving may take place independently of one another.

[0050] A second preferred embodiment of the method is proposed in order to increase the transmission rate or data transfer rate. The correspondingly necessary hardware configuration is shown in FIG. 8. In this variant, a plurality of voltage levels, preferably 16, are used to encode the information sent from the communication adapter 7 to the IC-CPD 3. Likewise, a plurality of different pulse widths, preferably 16, are used on the CP signal 4 to encode the information sent from the communication adapter 7 to the IC-CPD 3. For this purpose, T3, T4, R.sub.low, and R.sub.high are replaced by a controllable power source. This allows a plurality of bits to be transmitted per PWM pulse. Since one byte may thus be transmitted with two PWM pulses, the transmission rate increases to 500 bytes/sec. (16 levels at 8N0). Theoretically, this quantization may be increased even further. However, this also increases the requirement for data acquisition in the IC-CPD 3, which in turn leads to additional costs.

[0051] The following table shows an example of a 16-bit quantization:

TABLE-US-00001 Level [V] Current [mA] Pulse width [s] Coding 9.000 3.000 950 1111t -> 0xf -> 15 8.625 3.375 900 1110t -> 0xe -> 14 8.250 3.750 850 1101t -> 0xd -> 13 7.875 4.125 800 1100t -> 0xc-> 12 7.500 4.500 750 1011t -> 0xb -> 11 7.125 4.875 700 1010t -> 0xa -> 10 6.750 5.250 650 1001t -> 0x9 -> 9 6.275 5.625 500 1000t -> 0x8 -> 8 6.000 6.000 450 0111t -> 0x7 -> 7 5.625 6.375 400 0110t -> 0x6 -> 6 5.250 6.750 350 0101t -> 0x5 -> 5 4.875 7.125 300 0100t -> 0x4 -> 4 4.500 7.500 250 0011t -> 0x3 -> 3 4.125 7.875 200 0010t -> 0x2 -> 2 3.750 8.250 150 0001t -> 0x1 -> 1 3.375 8.625 100 0000t -> 0x0 -> 0

[0052] The previously disclosed preferred embodiments 1 and 2 communicate in the positive level of the CP signal 4. The pulse width is also used for communication. This means that the diagnostic PC 8 takes the place of the battery-powered electric vehicle 6 and thus it is not possible to communicate simultaneously with charging of the vehicle battery.

[0053] In order to enable this, a third preferred embodiment is disclosed that eliminates this limitation. In Variant 3, only the negative level of the CP signal 4 is used for communication with the diagnostic PC 8. However, since both directions of communication between the diagnostic PC 8 and the IC-CPD 3 use the negative level, only a half-duplex operation is possible. In other words, the IC-CPD 3 responds only to a request from the diagnostic PC 8 and the IC-CPD 3 is not permitted to transmit independently (master-slave operation). For transmission, the low and high logic states are each assigned a voltage level: for example, low 12 V and high 11.5 V. The high level is determined by the selection of components T3/4 R.sub.low, and D (see FIG. 9). The levels in this example were chosen to be within the tolerance range of the IEC-61851 standard (12 V +/1 V). The above-described connection setup procedure is used only when the communication adapter 7 determines that the IC-CPD 3 is in the A state. If the IC-CPD 3 is already in charging mode (state C) or state D, a connection is not necessary.

[0054] A corresponding change of the hardware of the adapter 7 is necessary for the third preferred embodiment. This is shown in the circuit diagram of FIG. 9. The schematic relationship for the overall system for simultaneous charging and communication with the IC-CPD 3 through the adapter 7, however, may be seen in FIG. 4.

[0055] FIG. 10 shows, by way of example, the signal curve during charging for the communication according to the invention. At the time t1, a start bit (11.5V) is transmitted, followed by 8 data bits (0010110t>015). The transmission does not use a stop bit or parity bit. The achieved transmission rate is 111 byte/sec.

[0056] Since the transmission rate in the third preferred embodiment is very low, a fourth preferred embodiment is presented. Variant 4 differs from Variant 3 only in that the transmission of a byte is compressed in time in such a way that it fits into the low phase of a PWM signal 13. The hardware used remains unchanged. Only the firmware in the microcontroller of the adapter 7 and in the IC-CPD 3 for evaluating the CP signal 4 is adjusted.

[0057] FIG. 11 shows the method of the invention for the fourth preferred embodiment. The position of the start bit (t1) is always synchronous with the positive edge of the PWM signal 13 at t0+560 s. Thus, it may be ensured that charging may still take place at 32 A (53% ED) and that transmission does not take place in the positive part of the PWM signal 13. FIG. 11 shows how a start bit, 8 data bits (MSB-first) and a parity bit are transmitted. A transmission error may be detected by using a parity bit. The transmission rate achieved is thus 1000 bytes/sec, which is significantly higher than in the third preferred embodiment.

[0058] The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention:

[0059] 1 Power grid

[0060] 2 Charging current/energy

[0061] 3 IC-CPD

[0062] 4 CP data signal

[0063] 5 Vehicle coupling

[0064] 6 Battery-powered electric vehicle

[0065] 7 Communication adapter

[0066] 8 Diagnostic PC

[0067] 9 USB connection

[0068] 10 Vehicle connector

[0069] 11 CP data line

[0070] 12 Amplitude-modulated signal

[0071] 13 Pulse width-modulated signal