Communication on a pilot wire
Systems and methods are disclosed for communicating on a pilot wire between Electric Vehicle Service Equipment (EVSE) and an Electric Vehicle (EV). In an example embodiment, a modem is coupled to the pilot wire that couples the EVSE and the EV. The modem transmits both pulse width modulation (PWM) command signals and power line communication (PLC) signals to a remote device via the pilot wire. The modem interleaves the PWM and PLC signals on the pilot wire so that latency requirements for the PWM signals are maintained. The modem supports parallel protocol stacks in which PLC signals are processed in a first path and PWM signals are processed in a second path that bypasses the first path and provides the PWM signals directly to a MAC layer. The modem may create a modified frame for the PLC signals to maintain the latency requirements.
1. A circuit, comprising:
a modem coupled to a pilot wire in an electric vehicle charging system, the pilot wire coupling the electric vehicle service equipment and an electric vehicle, the modem operating to transmit both pulse width modulation (PWM) command signals and power line communication (PLC) signals to a remote device via the pilot wire, and the modem interleaving the PWM and PLC signals on the pilot wire so that latency requirements for the PWM signals are maintained, wherein a plurality of PWM messages are assigned a highest priority and are transmitted in a next available contention free slot, and wherein the plurality of PLC messages are assigned an intermediate or normal traffic priority with a maximum back-off slot duration.
2. The circuit of claim 1 , wherein the modem is located in electric vehicle service equipment of the electric vehicle charging system, and the remote device is a modem in an electric vehicle, and wherein the latency requirements comprise a twenty-five milliseconds maximum round-trip transmission time for the PWM command signals.
3. The circuit of claim 1 , wherein the modem is located in an electric vehicle, and the remote device is a modem coupled to electric vehicle service equipment, and wherein the latency requirements comprise a twenty-five milliseconds maximum round-trip transmission time for the PWM command signals.
4. The circuit of claim 1 , wherein the PLC signals are Orthogonal Frequency-Division Multiplexing (OFDM) signals.
5. The circuit of claim 1 , wherein the modem interleaves the PWM and PLC signals by identifying when PWM messages are transmitted, and then transmitting a PLC message between a PWM message and a PWM response.
6. The circuit of claim 4 , wherein the OFDM signals comply with a PRIME (Powerline Related Intelligent Metering Evolution) or G 3 standard.
7. A circuit, comprising:
a modem coupled to a pilot wire in an electric vehicle charging system, the pilot wire coupling the electric vehicle service equipment and an electric vehicle, the modem operating to transmit both pulse width modulation (PWM) command signals and power line communication (PLC) signals to a remote device via the pilot wire, the modem interleaving the PWM and PLC signals on the pilot wire so that latency requirements for the PWM signals are maintained, and the modem supporting parallel protocol stacks in which PLC signals are processed in a first path and PWM signals are processed in a second path that bypasses the first path and provides the PWM signals directly to a MAC layer.
8. The circuit of claim 7 , wherein the first path includes a SEP 2.0 application convergence protocol stack, a IPv6 convergence layer, and a 6LowPAN convergence layer.
9. The circuit of claim 7 , wherein the PLC signals are processed in the MAC layer using Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA).
10. The circuit of claim 7 , wherein the PLC signals are Orthogonal Frequency-Division Multiplexing (OFDM) signals.
11. The circuit of claim 7 , wherein the modem interleaves the PWM and PLC signals by identifying when PWM messages are transmitted, and then transmitting a PLC message between a PWM message and a PWM response.
12. The circuit of claim 10 , wherein the OFDM signals comply with a PRIME (Powerline Related Intelligent Metering Evolution) or G 3 standard.
13. A circuit, comprising:
a modem coupled to a pilot wire in an electric vehicle charging system, the pilot wire coupling the electric vehicle service equipment and an electric vehicle, the modem operating to transmit both pulse width modulation (PWM) command signals and power line communication (PLC) signals to a remote device via the pilot wire, the modem interleaving the PWM and PLC signals on the pilot wire so that latency requirements for the PWM signals are maintained, and wherein the modem operates to create a frame comprising:
a preamble, a header, and a payload;
the preamble comprising a positive phase chirp sequence and a negative phase chirp sequence;
the header comprising four frame control header symbols; and
the payload comprising a maximum of seven symbols.
14. The circuit of claim 13 , wherein the frame control header symbols comprise a maximum of twelve bits, wherein:
two bits represent a selected modulation scheme;
three bits represent a packet length; and
five bits are used for redundancy or error detection.
15. The circuit of claim 13 , wherein the PLC signals are Orthogonal Frequency-Division Multiplexing (OFDM) signals.
16. The circuit of claim 13 , wherein the modem interleaves the PWM and PLC signals by identifying when PWM messages are transmitted, and then transmitting a PLC message between a PWM message and a PWM response.
17. The circuit of claim 15 , wherein the OFDM signals comply with a PRIME (Powerline Related Intelligent Metering Evolution) or G 3 standard.
18. A circuit, comprising:
a modem coupled to a pilot wire in an electric vehicle charging system, the pilot wire coupling the electric vehicle service equipment and an electric vehicle, the modem operating to transmit both pulse width modulation (PWM) command signals and power line communication (PLC) signals to a remote device via the pilot wire, and the modem interleaving the PWM and PLC signals on the pilot wire so that latency requirements for the PWM signals are maintained, wherein the modem operates to communicate with the remote device in a combined CENELEC A and B band using fifty-five tones in an Orthogonal Frequency-Division Multiplexing (OFDM) signal.
19. A circuit, comprising:
a modem coupled to a pilot wire in an electric vehicle charging system, the pilot wire coupling the electric vehicle service equipment and an electric vehicle, the modem operating to transmit both pulse width modulation (PWM) command signals and power line communication (PLC) signals to a remote device via the pilot wire, and the modem interleaving the PWM and PLC signals on the pilot wire so that latency requirements for the PWM signals are maintained, wherein the modem operates to communicate with the remote device in a combined CENELEC A, B and C band using sixty-two tones in an Orthogonal Frequency-Division Multiplexing (OFDM) signal.
20. A method, comprising:
coupling a modem to a pilot wire in an electric vehicle charging system, the pilot wire coupling the electric vehicle service equipment and an electric vehicle;
interleaving pulse width modulation (PWM) command signals and power line communication (PLC) signals on the pilot wire in a manner that maintains latency requirements for the PWM signals;
processing the PLC signals in a first path through a protocol stack; and processing the PWM signals in a second path through the protocol stack, the second path bypasses the first path and providing the PWM signals directly to a MAC layer; and
transmitting both the PWM and PLC signals by the modem to a remote device via the pilot wire.
21. The method of claim 20 , wherein the modem is located in electric vehicle service equipment of the electric vehicle charging system, or in an electric vehicle, and wherein the latency requirements comprise a twenty-five milliseconds maximum round-trip transmission time for the PWM command signals.
22. A method, comprising:
coupling a modem to a pilot wire in an electric vehicle charging system, the pilot wire coupling the electric vehicle service equipment and an electric vehicle;
interleaving a plurality of pulse width modulation (PWM) command signals and power line communication (PLC) signals on the pilot wire by identifying when PWM messages are transmitted, and then transmitting a PLC message between a PWM message and a PWM response; and
transmitting both the PWM and PLC signals by the modem to a remote device via the pilot wire.
23. A method, comprising:
coupling a modem to a pilot wire in an electric vehicle charging system, the pilot wire coupling the electric vehicle service equipment and an electric vehicle; interleaving pulse width modulation (PWM) command signals and power line communication (PLC) signals on the pilot wire in a manner that maintains latency requirements for the PWM signals;
assigning PWM messages a highest priority;
assigning PLC messages an intermediate or normal traffic priority with a maximum back-off slot duration; and
transmitting both the PWM messages and PLC signals in a next available contention free slot via the pilot wire.
24. A method, comprising:
coupling a modem to a pilot wire in an electric vehicle charging system, the pilot wire coupling the electric vehicle service equipment and an electric vehicle;
interleaving pulse width modulation (PWM) command signals and power line communication (PLC) signals on the pilot wire in a manner that maintains latency requirements for the PWM signals;
creating a frame comprising a preamble, a header, and a payload;
the preamble comprising a positive phase chirp sequence and a negative phase chirp sequence;
the header comprising four frame control header symbols;
the payload comprising a maximum of seven symbols; and
transmitting both the PWM and PLC signals via the pilot wire.
25. The method of claim 24 , wherein the frame control header symbols comprise a maximum of twelve bits, wherein:
two bits represent a selected modulation scheme;
three bits represent a packet length; and
five bits are used for redundancy or error detection.
26. A method, comprising:
coupling a modem to a pilot wire in an electric vehicle charging system, the pilot wire coupling the electric vehicle service equipment and an electric vehicle;
interleaving pulse width modulation (PWM) command signals and power line communication (PLC) signals on the pilot wire in a manner that maintains latency requirements for the PWM signals; and
communicating by the modem with the remote device in a combined CENELEC A and B band using fifty-five tones in an Orthogonal Frequency-Division Multiplexing (OFDM) signal.
27. A method, comprising:
coupling a modem to a pilot wire in an electric vehicle charging system, the pilot wire coupling the electric vehicle service equipment and an electric vehicle;
interleaving pulse width modulation (PWM) command signals and power line communication (PLC) signals on the pilot wire in a manner that maintains latency requirements for the PWM signals; and
communicating by the modem with the remote device in a combined CENELEC A, B and C band using sixty-two tones in an Orthogonal Frequency-Division Multiplexing (OFDM) signal.
28. A pilot wire cable circuit, comprising:
a modem coupled to a pilot wire cable in an electric vehicle charging system, the pilot wire cable coupling the electric vehicle service equipment and an electric vehicle, the modem operating to transmit both pulse width modulation (PWM) command signals and power line communication (PLC) signals to a remote device via the pilot wire cable, and
the modem interleaving the PWM and PLC signals on the pilot wire cable so that latency requirements for the PWM signals are maintained, the modem supporting parallel protocol stacks in which PLC signals are processed in a first path and PWM signals are processed in a second path that bypasses the first path and provides the PWM signals directly to a MAC layer.