HK1092773B - Inductive power coupler - Google Patents

Description

Inductive energy coupler

Technical Field

The present invention relates to inductive energy coupling and may be used to provide power to elevator hall fixtures, including call button lights, directional lights, and floor indicators, to reduce building wiring. Wireless power can be provided to the hall fixtures by inductively coupling power to the elevator while the elevator is on the landing.

Background

Elevator systems are provided with hall fixtures at each floor, including directional indicators, hall call buttons, and in some cases, elevator position indicators. Traditionally, hall fixtures at each floor are powered by wires running through the hall, and signal communication between each floor and a controller, typically located at the top of the hoistway between machines, is provided by additional wires. To reduce the amount of wiring, modern systems use serial communication buses, which typically require two wires for communication, two wires for power, one bus for each of the lights and call buttons. New building wiring requires a lot of installation time and makes modernization of existing elevators very difficult. Moreover, working in the hoistway is dangerous and should be avoided if possible.

Communication of hall fixtures has been accomplished wirelessly via radio frequency (or other) wireless communication. However, there is still a requirement to provide power through wires that need to be installed specifically into the building during initial construction of the elevator system, or as a result of modernization.

It has been proposed to use large coils disposed on the hoistway walls with large air gaps, and the gap between the moving and stationary portions of the elevator system can be 30 mm (1.2 inches), as required by common codes, so that power can be inductively coupled from the hoistway to the hoistway walls to power the fixtures when the hoistway is at a landing. It has also been proposed to effectively achieve magnetic power coupling between the elevator car and the hoistway walls by means of a coil having a large C-shaped core. It has been found that large coils and large C-shaped cores with large air gaps are not able to efficiently transfer the necessary power in a compact and efficient manner.

Disclosure of Invention

The objects of the present invention include: improved magnetic coupling, enabling contactless power transfer, providing improved wireless elevator hall fixtures power transfer; and to provide improved power coupling of elevator hall fixtures that receive power without the need for building wiring.

The present invention has found that by providing a large area magnetic coupling between a primary winding provided on the elevator car and a secondary winding provided on a fixed structure using a ferrite core that is much larger than the coil winding, an efficient wireless inductive coupling of power transfer from the primary coil to the secondary coil can be achieved.

According to the invention, the magnetic dynamic coupler comprises a very small ferrite material with a large low reluctance path through the required air gap, e.g. the elevator/hoistway gap, thus saving cost and space and reducing the voltage/current requirements of the drive electronics. Both the primary and secondary comprise ferrite cores around which the winding is wound, said ferrite cores being surrounded by said winding along the length of said winding and over a portion of the width of said winding. The length of the ferrite core is at least the same as the length of the winding, and the width and length of the ferrite core are between 2 and 10 times the length of the air gap between the primary winding and the secondary winding. According to the invention, the inductive power coupling means comprise a coupling high-frequency power (for example, several tens of kilohertz), which can be provided by means of an H-bridge driven by direct current rectified from the line voltage of a common building, these devices constituting a high-frequency alternating current power supply. On the secondary side, the received high frequency signal may simply be rectified for charging the battery, which may provide power to the fixture when needed.

According to the invention, the power for the elevator hall fixtures is supplied by magnetic coupling with the power supply of the elevator car.

The present invention provides a power coupling that has a wide variety of uses, for example, eliminating any electrical wiring required to install an elevator hall fixture.

Other objects, features and advantages of the present invention will become more apparent in the light of the following detailed description of exemplary embodiments thereof, as illustrated in the accompanying drawing.

Drawings

Fig. 1 is a front view of a doorframe of an elevator hall, on which a fixing device is provided, and which uses a magnetic coupling as a power source according to the present invention;

fig. 2 is a rear view of the hall door frame of fig. 1;

fig. 3 is a partial top view, partially in section, of the door frame and elevator car of fig. 1;

FIG. 4 is a perspective view of the magnetic coupling of the present invention.

Detailed Description

Providing power to elevator hall fixtures is one example of the use of the present invention.

Referring to fig. 1, a doorway 13 of a landing 14 of an elevator includes a hoistway doorway 16 formed by a door frame 17. Doorway 16 is closed by hoistway doors 19, 20 except when the cab is parked at landing 14 (which in this case means stopping and opening the doors). The door frame includes a call assembly 22 having one or two hall call buttons, an up call button 23 and a down call button 24 in a conventional manner. The call button may be illuminated by an LED or other suitable means to indicate that a call has been placed. The door frame 17 also includes a light fixture 27 provided with one or two conventional directional arrows, such as an up directional arrow 28 and a down directional arrow 29, which are selectively illuminated to indicate the direction of elevator travel. The arrows may be illuminated with high intensity LEDs, or by other suitable means, to indicate the direction of travel of the elevator car.

The fixtures 22, 27 may be powered by the inductive coupler 32 of the present invention, as best seen in fig. 2.

In fig. 2, the secondary winding 70 of the inductive coupler is shown connected to the light fixture 27 by cable 50 and to the call fixture 22 by cable 51. The cables 50, 51 are arranged in the door frame 17. The lamp fixture 27 may be provided with an electronics assembly 54 and an energy storage device, which may be a battery 55 or an oversized capacitor, as is known in the art. The electronic components may include circuitry that receives high frequency current from the inductive coupler secondary 32, rectifies it, and charges the battery 55 with current, as is also well known to those skilled in the art. The electronics package 54 also includes communications with the elevator controller, such as may be accomplished by radio frequency electromagnetic radiation, monitors the remaining power of the battery 55, and controls power for the directional lights 28, 29, and the up and down hall call buttons 23, 24. The assembly 54 may take the form of a Piconet (Piconet) module, as disclosed in co-pending co-owned patent application PCT/US02/32848, which may include a bluetooth compliant module for use in the manner described in that application. Other electronic components may be used if desired, may operate with very low power consumption and provide appropriate control and communication.

An efficient inductive coupler secondary winding 70 has few turns of wire 71 but a large ferrite core 72, as shown in fig. 3 and 4. An inductive coupler primary 75 on the cab, similar to the coupler secondary 70, receives high frequency energy (e.g., about 20 kilohertz) from the H-bridge 80. In response to a conventional ac line voltage 83, the H-bridge 80 operates under dc current provided by a rectifier 82, the frequency of the H-bridge 80 being set by an oscillator 81 as is known in the art.

Referring now to fig. 4, primary 75 of coupler 32 has a primary winding 86 wound around a core 87, both of which may be identical to winding 71 and core 72 of secondary 70. However, to reduce the ac and dc impedance of the primary winding 86, 2 times as many windings of the secondary coil 71 may be included, driven in parallel, or more, of the same size.

To avoid damage to nearby structures having magnetic reluctance, the primary and secondary windings are provided with shields 84, 85, which are at least as large as the magnetic cores 72, 87, the shields being made of aluminum or other non-magnetic material. Air gaps may also be provided between the shield and the respective cores.

The cores 70, 75 are ferrite to provide minimal reluctance to the magnetic field. Thus increasing the efficiency of the power transfer from the primary to the secondary.

The width and length dimensions of the core, L and W respectively, should be 2 to 10 times the required air gap S.

The thickness T of the core should be large enough to prevent saturation or overheating of the core. Increasing the cross-sectional area obtained by multiplying the core thickness T by the core length L may reduce the likelihood of saturation and overheating. But L should be increased with reference to T in order to maximize the effective cross section of the magnetic circuit air gap. Thus, the thickness T of the core is kept relatively small, less than 25% of the width, preferably close to 5%. The thinnest magnetic core, which is less than 5% of the width, may be used, but may present manufacturing problems. The exact thickness is determined by the material properties of the particular ferrite used. Examples include:

width W is between 60 and 300 mm;

the length L is between 60 and 300 mm;

the thickness T is between 3 and 30 mm;

the length L of each core 70, 75 can be selected to accommodate the length of the primary and secondary coils 71, 86; in some cases, however, the core may be provided with extensions on both sides of the coil to increase coupling, if desired.

Claims (5)

1. An inductive energy coupler, comprising:

a primary coil disposed on the elevator car,

a secondary coil disposed on a fixed structure so as to be separated from the primary coil by an air gap;

the primary and secondary coils are each provided with a thin ferrite core with a coil surrounding the core;

each of said core sections having a width extending outwardly from the corresponding coil, said core sections having a width and length between 2 and 10 times the length of said air gap and a thickness of between 5% and 25% of said width; and is

The primary coil transfers power to the secondary coil.

2. The inductive energy coupler of claim 1, wherein said primary and secondary coils are separated by a gap on the order of 25 to 35 millimeters.

3. The inductive energy coupler of claim 1,

said thickness is between 3 mm and 30 mm;

said length is between the order of 60 mm and 300 mm;

the width is between 60 mm and 300 mm in magnitude.

4. The inductive energy coupler of claim 1,

an elevator hall fixture is coupled with the secondary coil to receive power from the secondary coil.

5. The inductive energy coupler of claim 4,

the elevator hall fixture includes a light indicator.