Communication on a Pilot Wire
First Claim
1. A circuit, comprising:
- a first modem coupled to a pilot wire system, the pilot wire system coupling electric vehicle service equipment and an electric vehicle and having a pilot wire carrying pulse width modulation (PWM) signals, the first modem transmitting communication signals to a second modem via the pilot wire; and
an interface circuit coupling the first modem to the pilot wire, the interface circuit having an impedance that is larger than an effective impedance of the pilot wire system.
1 Assignment
0 Petitions
Accused Products
Abstract
Systems and methods are disclosed for communicating on a pilot wire between Electric Vehicle Service Equipment (EVSE) and an Electric Vehicle (EV). The EVSE and EV exchange a Pulse Width Modulation (PWM) signal on the pilot wire to control charging operations of the EV. Data communications may also be transmitted on the pilot wire, such as between transmit and receive modems. The modems transmit communication signals either continuously, without regard to the state of the PWM signal, or only when the PWM is in an off-state. If transmitting while PWM is on, the modem needs a large coupling impedance and/or a large signal injection. To transmit only when the PWM is off, the modem may use a blocking diode in the coupling circuit or may synchronize to the pulses in the PWM signal.
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Citations
16 Claims
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1. A circuit, comprising:
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a first modem coupled to a pilot wire system, the pilot wire system coupling electric vehicle service equipment and an electric vehicle and having a pilot wire carrying pulse width modulation (PWM) signals, the first modem transmitting communication signals to a second modem via the pilot wire; and an interface circuit coupling the first modem to the pilot wire, the interface circuit having an impedance that is larger than an effective impedance of the pilot wire system. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A circuit, comprising:
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a first modem coupled to a pilot wire system, the pilot wire system coupling electric vehicle service equipment and an electric vehicle and having a pilot wire carrying pulse width modulation (PWM) signals, the first modem transmitting communication signals to a second modem via the pilot wire; and an interface circuit coupling the first modem to the pilot wire, the interface circuit comprising a diode that blocks the first modem communication signals from reaching the pilot wire when a PWM pulse is present on the pilot wire. - View Dependent Claims (9, 10, 11, 12)
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13. A method, comprising:
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coupling a first modem to a pilot wire system, the pilot wire system coupling electric vehicle service equipment and an electric vehicle and having a pilot wire carrying pulse width modulation (PWM) signals; monitoring the PWM signals to identify whether the PWM signals are on or off; transmitting communication signals from the first modem to a second modem via the pilot wire when the PWM signals are off; and stopping transmission of the communication signals when the PWM signals are on. - View Dependent Claims (14, 15, 16)
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Specification