Male power connector for bidirectional ac power

Abstract

A male power connector configured for carrying bidirectional AC grid power. The male power connector includes multiple pins configured to plug into a female receptacle. An insulating sleeve is configured to electrically isolate the pins when not plugged into a female receptacle. The insulating sleeve is retracted while the pins enter the female receptacle. At least one of the pins may be a hot pin configured to carry AC voltage. The male power connector includes an AC terminal and a normally-open relay connectable between the hot pin and the AC terminal. The relay is configured to close when the insulating sleeve is retracted and when the male power connector is inserted into a live female receptacle to enable AC power flow in either direction.

Description

[0001] MALE POWER CONNECTOR FOR BIDIRECTIONAL AC POWER

[0002] BACKGROUND

[0003] 1. Technical Field

[0004] The present invention relates to a male power connector for either receiving power from an AC grid or for supplying power to the AC grid.

[0005] 2. Description of Related Art

[0006] Recent increased interest in renewable energy has led to increased research in systems for distributed generation of energy, such as photovoltaic systems (PV), fuel cells, batteries for electric vehicles, et cetera. Various topologies have been proposed for connecting distributed power sources to the grid, taking into consideration various parameters, such as voltage / current requirements, operating conditions, reliability, safety and costs.

[0007] Alternating current (AC) power plugs and sockets connect electric equipment to the AC mains electricity or grid power supply to buildings. Various different standard systems of plugs and sockets are used around the world.

[0008] A plug is generally a connector attached to an electrically operated device or appliance. The socket is fixed on equipment or on a building connected to an energised electrical circuit. The plug is a male connector, with pins that protrude and match the openings and contacts in the female socket or receptacle. Some plugs may have female contacts that are used only for an earth ground connection.

[0009] Single-phase sockets have two current-carrying wires fed inside the building structure from the source of electrical power, generally from the electrical utility company. In the most common single phase wiring configuration, one wire is at high AC voltage, e.g. -230 Volts AC, rootmean-square (RMS) called the “hot” or “live” wire and the second current carrying wire is called “zero” or “neutral” is near zero voltage. Single phase sockets may also have a safety connection to earth ground. Typically electrical energy is not supplied to exposed pins or terminals on the socket, for safety. BRIEF SUMMARY

[0010] Various male power connectors and methods are herein disclosed for carrying bidirectional AC grid power. The male power connector includes multiple pins configured to plug into a female receptacle. An insulating sleeve is configured to electrically isolate the pins when not plugged into a female receptacle. The insulating sleeve is retracted while the pins enter the female receptacle. The pins may be exposed only to contacts of the female receptacle while plugging the male power connector into the female receptacle. A sensor may be configured to sense whether the insulating sleeve is retracted or is not retracted. At least one of the pins may be a hot pin configured to carry AC voltage. The male power connector may include an AC terminal and a normally-open relay connectable between the hot pin and the AC terminal. The relay may be configured to close when the insulating sleeve is retracted and when the male power connector is inserted into a live female receptacle to enable AC power flow in either direction. The relay may open or remain open when the male power connector is inserted into a female receptacle not carrying AC voltage to disable AC power flow into the female receptacle.

[0011] Various systems are provided herein including a male connector including pins configured to plug into a compatible female connector. The male connector includes an insulating sleeve configured to electrically isolate the pins when not plugged into a female connector. The insulating sleeve is retracted while the pins enter the female connector. A sensor may be configured to sense whether the insulating sleeve is retracted or is not retracted. An appliance may be connected to the male connector. A normally-open relay may connect between a pin of the male connector and the appliance. The relay may be configured to close when the insulating sleeve is retracted and when the male connector is inserted into a live female connector to enable power flow in either direction. The relay may be configured to be open when the male connector is inserted into a female connector not carrying voltage, to disable power flow into the female connector.

[0012] BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:

[0014] Figure 1 A illustrates a male AC power plug with an insulating sleeve configured to isolate pins of a male power plug , according to a feature of the present invention;

[0015] Figure IB illustrates male AC power plug shown in Figure 1A with the insulating sleeve retracted;

[0016] Figure 2A illustrates male AC power plug of Figures 1 A and IB with front housing removed showing the insulating sleeve in an outward (not retracted) position, isolating the pins. Figure 2B illustrates AC power plug of Figure 2A with insulating sleeve retracted as when male AC power plug is inserted into a female receptacle;

[0017] Figure 3 illustrates an electrical and mechanical schematic drawing 30, according to features of the present invention; and

[0018] Figure 4 is a flow diagram of a method, illustrating features of the present invention. The foregoing and / or other aspects will become apparent from the following detailed description when considered in conjunction with the accompanying drawing figures.

[0019] DETAILED DESCRIPTION

[0020] Reference will now be made in detail to features of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The features are described below to explain the present invention by referring to the figures.

[0021] By way of introduction, different aspects of the present invention are directed to an AC male power plug configured to receive AC power form an AC power grid from a conventional AC female receptacle and also to provide power to the AC grid through the conventional AC female receptacle. Normally, when receiving AC power the pins of the male power plug are inserted into the female receptacle and are not exposed. However, if contemplating use of a male plug for providing AC power to the grid, such as from an electrical storage device, battery or fuel cell; or power generator, the pins providing power may be exposed when the male plug is not inserted into the female receptacle. Such a use would not be considered safe as the exposed pins may cause electric shock, even electrocution, and are further liable to cause a short circuit and / or a ground fault. Moreover, another safety issue may relate to islanding. Islanding is a condition where a power generation or storage system is severed from the utility network, but continues to supply power to portions of the utility network after the utility power supply is disconnected from those portions of the network. Supply of electricity to the grid from a battery, generator or photovoltaic system may shock or electrocute repairmen after the grid is shut down by generating power as an island downstream. Thus, it is desirable to provide a feature in an AC connector which disables power flow into the AC grid if no AC power is detectable already in the AC grid.

[0022] Referring now to the drawings, reference is now made to Figures 1 A and IB, which illustrate a male AC power plug 10 according to features of the present invention. Figure 1A illustrates male AC power plug 10 with an insulating sleeve 12 isolating pins 11 of male power plug 10. Figure IB illustrates AC power plug 10 with insulating sleeve 12 retracted, exposing pins 11. During normal operation of male AC power plug 10, pins 11 may be exposed only when inserted into a compatible female AC receptacle. Front housing 13 and back housing 14 are also illustrated. Reference is now also made to Figures 2A and 2B illustrating male AC power plug 10 according to further internal features of the present invention, with front housing 13 removed for illustrative purposes. Figure 2A shows male AC power plug 10 with insulating sleeve in an outward (not retracted) position, isolating pins 11. Figure 2B illustrates AC power plug 10 with insulating sleeve 12 retracted as when male AC power plug is inserted into a female receptacle. One or more springs 16 may be used to maintain insulating sleeve 12 in the outward position, isolating pins 11 when AC power plug is not inserted into a compatible female receptacle. A sensor 15, which may electrically include a switch, e.g. single pole single throw (SPDT) is configured to mechanically sense a position of insulating sleeve 12 whether insulating sleeve 12 is outward (not partially retracted) and fully isolating pins 11 or whether insulating sleeve 12 is at least partially retracted.

[0023] Reference is now made to Figure 3, which includes an electrical and mechanical schematic drawing of male power connector 10, according to features of the present invention. Reference is also made to Figure 4, which includes a flow diagram 40 of a method, according to features of the present invention. A male power connector 10 is provided (step 41) to plug into an AC grid female receptacle 33. Insulating sleeve 12 electrically isolates (step 42) pins 11 when not plugged into female receptacle 33. While male power connector 10 is being inserted into a female receptacle 33, insulating sleeve 12 is retracted in a direction indicated by an arrow 35, to expose (step 43) pins 11 only to respective contacts of female receptacle 33. Mechanical sensor, e.g. switch 15 is shown to mechanical couple to insulating sleeve 12. Mechanical sensor 15 may be configured electrically to provide a sense signal (step 44) to the appliance that the appliance is plugged into or not plugged into a power outlet 33. The sense signal may be used to disable output power flow from the appliance when male power plug 10 is not plugged into female receptacle 33.

[0024] When male power plug 10 is inserted into a compatible female receptacle, insulating sleeve 12 is retracted. When insulating sleeve 12 is retracted, switch 15 closes, activating (closing) a relay 31 which is connected between hot pin 11 and hot terminal 32. Closing relay 31 enables power to flow, to or from an appliance connected to male power plug 10. When male plug 10 is being removed from a female receptacle, insulating sleeve 12 is at least partially retracted, exposing pins 11. Switch 15 opens, deactivating relay 31 which opens the connection between hot terminal 32 and hot pin 11, disabling power transfer in either direction. Operation of relay 31 is directed to protect against manual override of the electrical isolation of insulating sleeve 12, when the appliance is providing power. Also if the grid is down, the relay prevents the appliance from supplying power to the grid, which is a safety issue.

[0025] In alternative embodiments of the present invention, relay 31 may be implemented as part of a system including male power plug 10 and the appliance connected thereto.

[0026] The term “grid” or “power grid” as used herein refers to a network of power lines and associated equipment used to transmit and distribute electricity over a geographic area.

[0027] The terms “male power connector” and “male plug” are used herein interchangeably.

[0028] The term “appliance” as used herein refers to the equipment to which male connector 10 or any male connector is connected using a cable which may include an electrical generator, a distributed power source such as a photovoltaic system; and / or electrical storage such as a battery.

[0029] The terms “power outlet” and “female receptacle” are used herein interchangeably. The terms “male plug” and “female outlet”, as used herein refer to any international standard for connection to the AC power grid. The terms “male connector” and “female connector” refers to any male or female electrical connector respectively not necessarily AC nor necessarily a standard for AC grid power.

[0030] The term “hot” as used herein in context of electrical wiring, refers to a current carrying wire in a power grid which is normally at substantial voltage. The terms “hot wire” and “live wire” are used herein interchangeably. The term “neutral” as used herein in context of electrical wiring, refers to a current carrying wire at zero or near zero voltage.

[0031] The term “insulating” as used herein refers to electrical insulation characterized by non- electrically conductive materials such as glass, plastics or ceramics.

[0032] The transitional term “comprising” as used herein is synonymous with “including”, and is inclusive or open-ended and does not exclude additional element or method steps not explicitly recited. The articles "a", "an" is used herein, such as "a sleeve” or "a pin" have the meaning of "one or more" that is "one or more sleeves", "one or more pins".

[0033] All optional and preferred features and modifications of the described embodiments and dependent claims are usable in all aspects of the invention taught herein. Furthermore, the individual features of the dependent claims, as well as all optional and preferred features and modifications of the described embodiments are combinable and interchangeable with one another.

[0034] Although selected features of the present invention have been shown and described, it is to be understood the present invention is not limited to the described features.

Claims

CLAIMSTHE CLAIMED INVENTION IS:

1. A male power connector configured to carry bidirectional AC grid power, the male power connector including a plurality of pins configured to plug into a female receptacle, the male power connector comprising: an insulating sleeve configured to electrically isolate the pins when not plugged into a female receptacle, wherein the insulating sleeve is retracted while the pins enter the female receptacle, wherein at least one of the pins is a hot pin configured to carry AC voltage, an AC terminal; a normally-open relay connectable between the hot pin and the AC terminal, wherein the relay is configured to close when the insulating sleeve is retracted and when the male power connector is inserted into a live female receptacle to enable AC power flow in either direction.

2. The male power connector of claim 1, wherein the relay remains open when the male power connector is inserted into a female receptacle not carrying AC voltage, to disable AC power flow into the female receptacle.

3. The male power connector of claim 1, further comprising a sensor configured to sense whether the insulating sleeve is retracted or is not retracted.

4. A method for providing electrical safety while enabling a bidirectional AC power connection to a power grid, the method comprising: providing a male power connector including a plurality of pins configured to plug into a female receptacle; electrically isolating the pins when not plugged into a female receptacle; exposing the pins while the pins enter the female receptacle, wherein at least one of the pins is a hot pin configured to carry AC voltage; providing a normally-open relay connectable between the hot pin and an AC terminal; enabling the relay to close when the insulating sleeve is retracted and when the male power connector is inserted into a live female receptacle, thereby enabling AC power flow in either direction.

5. The method of claim 4, further comprising: enabling the relay to remain open when the male power connector is inserted into a female receptacle not carrying AC voltage, thereby disabling AC power flow into the female receptacle.

6. The method of claim 4, further comprising: said exposing the pins only to contacts of the female receptacle while plugging the male power connector into the female receptacle.

7. The method of claim 4, further comprising: sensing whether the insulating sleeve is retracted or is not retracted.

8. A system comprising: a male connector including a plurality of pins configured to plug into a compatible female connector, the male connector including an insulating sleeve configured to electrically isolate the pins when not plugged into a compatible female connector, wherein the insulating sleeve is retracted while the pins enter the female connector; an appliance connectable to the male connector; and a normally-open relay connectable between a pin of the male connector and the appliance, wherein the relay is configured to close when the insulating sleeve is retracted and when the male connector is inserted into a live female connector to enable power flow in either direction.

9. The system of claim 8, wherein the relay is configured to remain open when the male connector is inserted into a female connector not carrying voltage, to disable power flow into the female connector.

10. The system of claim 8, further comprising a sensor configured to sense whether the insulating sleeve is retracted or is not retracted.

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