Portable charging cable with in-line controller
A portable electric vehicle support equipment (EVSE) unit is formed as a cord of plural insulated conductors and a flexible outer sheath enclosing said plural insulated conductors. The cord includes an EVSE docking connector on a docking end of the cord and a utility plug on a utility end of the cord, said cord being divided into a docking section terminated at said docking connector and a utility section terminated at said utility connector. The cord further includes an in-line EVSE controller and a housing enclosing said controller, said housing sealed with said flexible outer sheath and disposed at an intermediate section of said cord between said docking and utility sections.
1. An EVSE cord comprising:
plural insulated conductors and a flexible outer sheath enclosing said plural insulated conductors,
an EVSE docking connector on a docking end of the cord and a utility plug on a utility end of the cord,
an in-line EVSE controller coupled between said docking and utility ends;
a control pilot conductor in said docking connector, wherein said in-line EVSE controller comprises:
a microprocessor comprising a serial port;
an analog buffer coupled between said microprocessor and said control pilot conductor;
a pulse generator coupled to said control pilot conductor and having a duty cycle controlled by said microprocessor; and
a temperature sensor having a temperature output coupled to said microprocessor, said temperature output representing a present temperature.
2. The EVSE cord of claim 1 wherein said in-line EVSE controller is connected in “series between conductors of said docking connector and conductors of said utility plug.
3. The EVSE cord of claim 1 wherein said duty cycle signifies a maximum current draw by an EV coupled to said EVSE cord.
4. The EVSE cord of claim 1 wherein said microprocessor is programmed to halt charging current flow through said EVSE cord whenever said present temperature exceeds a maximum operating temperature.
5. The EVSE cord of claim 1 wherein said microprocessor is programmed to adjust said duty cycle in response to said present temperature exceeding a predetermined threshold temperature less than a maximum operating temperature.
6. The EVSE cord of claim 1 further comprising a memory coupled to said microprocessor, said memory storing: (a) a nominal pulse duty cycle corresponding to a nominal value of maximum allowable current, (b) a predetermined threshold temperature, (c) a maximum operating temperature and (d) a set of program instructions executable by said microprocessor, upon said present temperature exceeding said predetermined threshold temperature, to reduce the pulse duty cycle of said pulse generator from said nominal pulse duty cycle to an adjusted pulse duty cycle by a reduction factor that is a function of the closeness of said present temperature to said maximum operating temperature.
7. The EVSE cord of claim 6 wherein said function is a proportional function.
8. The EVSE cord of claim 6 wherein said predetermined threshold temperature is in a range of 10% to 30% of said maximum operating temperature.
9. An EVSE cord comprising:
plural insulated conductors and a flexible outer sheath enclosing said plural insulated conductors;
an EVSE docking connector on a docking end of the cord and a utility plug on a utility end of the cord;
an in-line EVSE controller;
a control pilot conductor in said cord, wherein said in-line EVSE controller comprises:
a microprocessor comprising a serial port;
an analog buffer coupled between said microprocessor and said control pilot conductor; and
a serial bus connected between said serial port and said control pilot conductor.