My Contest Entry
Hybrid Vehicle “Docking Station” Provides Residential UPS
The Grand Prize – a Toyota Prius – can power a house if utility power fails. A drive-up “docking station” allows it to do so automatically. The system has three components - an automatic mating connector to the vehicle’s electric system, an inverter, and a transfer switch to connect selected household circuits to the inverter.
The novelty of the dock is its ability to automatically make and break a high-current electrical connection with reliability and complete safety. It comprises a horizontal bar roughly the width of the vehicle attached to two vertical stanchions which anchor and space triangular troughs whose entrance is three tire-widths across. They constrict near the attached end to one tire’s width and are vertically profiled to be first slightly inclined and then form a depression. When driven in, the tires are centered and held in the depression by the car’s weight. This assures precise positioning of the front bumper. To help initially align the vehicle, a vertical stalk with two side-mounted red LEDs and one face-mounted green LED is positioned in front of the driver. Only the green LED will be visible when the vehicle is centered while a red LED will show if too far left or right.
The car “docks” by being driven into the troughs. Each tire closes a switch which requires several pounds of actuation force. The separated switches prevent electrical operations unless the car is properly docked, which is indicated by blinking the green LED.
Docking positions the electrical connector mechanism on the bar to mate with a complementary connector on the vehicle. A protective, spring-loaded split door on the bumper is unlocked by a low-voltage, low current signal from the bar which releases an armature. Simultaneously, the current drain from the vehicle signals the docking station to extend the high-power mating connector from the bar into the bumper using a small motor and linear actuator or other extension mechanism. The vehicle connector has two tapered male pins far enough behind the bumper to allow the protective door to open without interference. The actuator extends two hyperboloid wire basket connectors into the bumper to mate with the pins. These connectors can withstand thousands of mating cycles without damage and with efficient ohmic contact. Conductor and pin size are selected for 50-100 amps. To undock, the vehicle backs up, demating the connectors.
When power fails, short outages are carried by the car’s battery; longer ones start the gasoline engine to both supply power and recharge the battery.
The docking station is the size and weight of sturdy lawn furniture and requires no great manufacturing expertise. The inverter requires some specialized design to match the electrical system of the hybrid vehicle to be docked. Transfer switches are standard appliances.
With increasing hybrid vehicle popularity, this novel “UPS” for many of America’s houses will benefit its owners and also stabilize our electric grid and our society against unforeseen events, accidental or deliberate.