PLUGGABLE DISPLAY WITH WIRELESS POWER AND DATA TRANSFER

FIELD OF THE INVENTION

The, present invention generally relates to display devices. In particular, the present invention relates to a display of a metering device which is coupled to a measuring unit by wireless Electro-Dynamic induction for receiving power and data. The display may be remotely plugged with the measuring unit without physical connectivity.

BACKGROUND OF THE INVENTION

Typically the metering devices include a measuring unit, a control unit, a display unit, and a power unit. The measuring unit senses an electrical parameter such as voltage, current and so forth. The control unit performs the necessary control functions to produce signals representative of the measured data. The display unit displays the signals corresponding to the measured electrical parameters. The power unit supplies energy to the metering device.

In certain scenarios, the measuring unit of the metering device needs to be attached to a location which may be difficult to reach for operators. In some other scenarios, the measuring unit may be enclosed within housing or a panel. In such scenarios, it is difficult to connect a display unit by physical wiring to such measuring unit. In order to connect the display unit to panel, a bigger hole is required to be made or drilled on the panel for holding the display unit with the measuring unit. Such bigger holes may lead to other problems. Further, before reading the measured parameters on the display unit the operator may need to engage in other tasks such as establishing linkage between the measuring unit and the display unit by physical engagement.

In view of above discussion, it is apparent that there is a need to provide a display device for an electrical metering device, which obviates the above mentioned disadvantages including hassles of making wiring connection with a measuring unit.

SUMMARY OF THE INVENTION

The main object of the present invention is to provide an intelligent display for a metering device, which is coupled to a measuring unit by wireless electro-dynamic induction to receive power and the measured data.

Another object of the present invention is to provide an intelligent display for a metering device, which may achieve maximum wireless transmission efficiency in receiving power and measured data from a measuring unit.

Another object of the present invention is to provide an intelligent display for a metering device, which is pluggable to a measuring unit without the use of clamps, latching brackets etc.

Another object of the present invention is to provide an intelligent display for a metering device, which may be used as a retro-fit or additional display for measuring unit without displays.

Another object of the present invention is to provide an intelligent display for a metering device, which eliminates the need of a physical power supply or dedicated power storage device such as batteries.

Another object of the present invention is to provide an intelligent display for a metering device which is simple in construction with reduced manufacturing cost.

In order to achieve the above mentioned objects the present invention discloses a pluggable display device located remotely from a measuring unit of an electrical metering device. The pluggable display device includes a secondary coil for establishing link for power and data transmission by wireless electro-dynamic induction from a primary coil located in the measuring unit, a control unit for energizing the display device from transmitted power and generating electrical signal from the transmitted data, and a display unit for displaying one or more electrical parameter based on the generated electrical signal, wherein, the secondary coil is aligned co-axially with the primary coil and is placed in proximity to achieve maximum efficiency in the electro-dynamic induction based wireless power and data transmission.

In another embodiment, the secondary coil is configured for unidirectional power transmission at low frequency band. The power transmission includes receiving power from the primary coil. In another embodiment, the secondary coil is configured for bidirectional data transmission at high frequency band. The data transmission includes receiving the one or more electrical parameter from the primary coil and sending user communication signal to the primary coil.

In another embodiment, the control unit further includes a signal processing unit for modulating or demodulating the transmitted power and data, a rectifier for rectifying the transmitted power; and a voltage regulator for regulating the rectified power based on power requirement of the display unit.

In another embodiment, the display unit comprises at least one selected from the group of a LCD screen, a LED screen, and an EINK screen.

In another embodiment, the pluggable display device includes a mounting means for engaging the display device with the measuring unit and co-axially aligning the secondary coil with the primary coil. In an embodiment, the mounting means includes at least one selected from a plurality of permanent magnets and a magnetic strip.

In yet another embodiment, the pluggable display device further includes a memory unit for storing the one or more electrical parameter.

It is to be understood that both the foregoing general description and the following detailed description of the present embodiments of the invention are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide a further understanding of the invention and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the invention and together with the description serve to explain the principles and operation of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and other advantages of the invention will be better understood and will become more apparent by referring to the exemplary embodiments of the invention, as illustrated in the accompanying drawings, wherein

FIG. 1 schematically illustrates configuration of a display device which receives power and data by wireless electro-dynamic induction link from a measuring unit of a metering device along with the scheme of co-axial alignment of a secondary coil of the display device with a primary coil of the measuring unit in order to achieve maximum transmission efficiency according to one embodiment of the present invention; and

FIG. 2 schematically illustrates the mounting scheme of the display device of FIG. 1 for co-axial alignment of the secondary coil with the primary coil according to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made to the exemplary embodiments of the invention, as illustrated in the accompanying drawings. Where ever possible same numerals will be used to refer to the same or like parts.

Disclosed herein is an intelligent display device which receives one or more electrical parameter and power from a measuring unit of a metering or monitoring device by electro-dynamic induction link based wireless connectivity between the measuring unit and the remote display device. The invention explains the scheme for designing the wireless inductive link which works both as an energy link to power up the display device as well as a communication link for retrieving the data from the remote measuring unit. The same set of inductive links is used for the transfer of the measured data and power. FIG.1 schematically illustrates the configuration of such a display device 112 which receives power and data by wireless electro-dynamic induction link from a measuring unit 102 of a metering device 100 according to one embodiment of the present invention. The metering device 100 includes a measuring unit 102, and a primary coil 104. The measuring unit 102 may be enclosed within a factory-fitted panel 106. A hole 108 may be drilled on the panel 106 to utilize the display device 112 as retro-fit or additional display device. Further the display device 112 may include a secondary coil 114, and a display unit 116. The panel 106 may include a mounting means such as a plurality of magnetic strips 110 for properly aligning the secondary coil 114 with the primary coil 104 to ensure maximum transmission efficiency. The display device 112 may also include complementary magnetic strips for plugging the display device 112 on the panel 106. The metering device 100, for example, may include a voltmeter, an ammeter, a watt meter and so forth.

The measuring unit 102 may sense one or more electrical parameters. The electrical parameters may include, for example, current, voltage, power and so forth. The measuring unit 102 may include a voltage measurement circuit, a current measurement circuit, and so forth for measuring electrical current, voltage, and power. From the current and/or voltage measurement circuit the measured data is transmitted to the measuring unit 102 by applying variable impedance device coupled to the current and/or voltage measurement circuit. From the measuring unit 102 this measured data is modulated or demodulated in amplitude by a signal processing unit (shown as 202 in FIG. 2) according to the present embodiment of the invention. The amplitude modulated data is then transferred by wireless induction link from the primary coil 104 to the secondary coil 114 of the display device 112.

The measuring unit 102 may include a control unit for controlling the processing, storage, and transmission of measured data. The control unit, for example, may be a low power microcontroller. An algorithm for such control operation may be programmed in such control unit. The wireless data transmission to the remote display device 112 may depend on communication between the measuring unit 102 and the display device 112. For example, if the display device 112 is a single parameter display then only one parameter is transmitted and if the display device 112 is a multi-parameter display, then multiple parameters are transmitted wirelessly. In one embodiment, the induction link may be configured for bi-directional data transmission with specific code and data modulation sequence proposed for such data transmission.

Power also may be transmitted to the secondary coil 114 of the display device 112 using the similar scheme. However, only a very low power may be transmitted uni-directionally from the primary coil 104 to the secondary coil 114 using this scheme. The wireless transmission scheme may be optimized by placing the measuring unit 102 and the display device 112 in proximity and the primary coil 104 and the secondary coil 114 in co-axial alignment.

The display device 112 may be coupled with the measuring unit 102 with improved user safety features. For example, in the absence of the display unit 112, the wireless transmission scheme of the measuring unit 102 may enter into a stand-by mode. Further necessary scheme may be implemented to ensure a high speed coupling interface providing instant connectivity. The total link efficiency is the product of the power transfer efficiency and the data transfer efficiency. However, the power transfer efficiency may be considered as primary factor and the data transfer efficiency may be considered as secondary factor. Efficient coupling between the primary coil 104 and the secondary coil 114 may be achieved by below mentioned arrangements:

• Choosing appropriate dimension of the inductive links such as primary and secondary coils 104 and 114

• Keeping proximity between the primary and secondary coils 104 and 114

• Flat surface may be chosen to prevent misalignment

• Adding magnetic shielding material for maximum power and data transfer and guided positioning with tactile feedback.

In order to achieve optimal alignment for maximum power transfer efficiency and protection against leakage the guide may be provided. A separation of the remote display device 112 beyond certain distance may cause leakage in wireless induction coupling.

The primary coil 104 generates the magnetic field necessary for power and data transfer. An inductive link driver such as an amplifier may be needed to drive high currents into the primary coil 104 in order to generate the magnetic fields required for power transfer. The inductive link driver may have the following configurations:

• Switch mode amplifier where the active elements operate as a switch so that they only draw currents without carrying a voltage. This will drastically minimize the dissipation in the active elements and avoid its breakdown.

• The driver output should be a pure sinusoid because only the fundamental component is received at the secondary coil 114.

• The primary inductance is tuned with a resonant capacitor. The resonant capacitor may enable cancelling out of the large primary leakage inductance that typically occurs with small coupling factors. This leakage inductance causes a large primary coil voltage as the inductive powering requires large coil currents.

As stated above, the measuring unit 102 may be enclosed within the panel 106. The hole 108 may be drilled on the panel 106 for allowing the electro-dynamic field to propagate to the display device 112. In one embodiment, the panel 106 may include magnetic strips as mounting means to attach to the display device 112 with the panel (shown as 204 in FIG. 2). The magnetic strips also facilitate in co-axial alignment of the secondary coil 114 with the primary coil 104 for maximum transmission efficiency.

The display device 112 includes the secondary coil 114 for receiving the electro-dynamic induction fields from the remote measuring unit 102. The received signal is then modulated or demodulated by another signal processor (shown as 206 in FIG. 2). The AC voltage induced in the secondary coil 114 due to this magnetic induction is then rectified by a rectification circuitry. The rectified DC voltage is then supplied to the components of the display device 112. The display device 112 may further include a voltage regulator to smooth out the variation on the induced voltage caused by variations in the coupling and loading conditions and supplying the necessary power to the display unit 116 and a control unit.

Further, the display device 112 includes the control unit for generating electrical signals from the received data. The electrical signals may be representative of the one or more electrical parameters sensed by the measuring unit 102. The control unit, for example, may include a low power micro-controller. Finally, the display unit 116 displays the measured electrical parameters based on such electrical signal. The intensity of display on the display unit 116 may depend on the power transfer efficiency to the remote display device 112. The display unit 116, for example, may be a LCD screen, a LED screen, an EINK screen and so forth. The display unit 116 may be of any shape and may not be limited to the shape of the drilled hole 108. The LCD/LED display screen may be modular in construction and may be attached through a plug or with high density glue to the panel. However, the EINK display may be a flexible module which may have high density glue and can easily stick to the panel. Further, the display device 112 may include a memory unit for storing the measured electrical parameters. The stored electrical parameters may be used for transferring the data to a PC after the display device 112 is detached from the panel 106.

In this way, the double tuned circuit of the present invention represented by a Class E amplifiers feature a series-tuned coil with a second capacitor in parallel. This offers an efficient scheme as it combines the benefits of low-current operation of a parallel resonance with the low-voltage operation of a series resonance.

It may be apparent from the above discussion that the proposed system includes two inductive links only for powering, controlling and data retrieval of the remote display device 112, which is located in the near field of such links, but is not physically connected to it. In the present scheme, the same inductive links including the primary coil 104 and the secondary coil 114 is used for both power transfer and data transmission. However, power and data are modulated at two different frequency bands for optimal transfer. The power is transmitted at lower spectrum such as below 100 KHz (<100 KHz) and data is transmitted at higher spectrum such as at the range of MHz (few MHz).

The present display device 112 finds applications primarily as retro-fit or additional display device for a measuring unit without display.

It is to be understood by a person of ordinary skill in the art that various modifications and variations may be made without departing from the scope and spirit of the present invention. Therefore, it is intended that the present invention covers such modifications and variations provided they come within the ambit of the appended claims and their equivalents.

We claim:

1. A pluggable display device located remotely from a measuring unit of an electrical
metering device comprising:

a secondary coil for establishing link for power and data transmission by wireless electro-dynamic induction from a primary coil located in the measuring unit;

a control unit for energizing the display device from transmitted power and generating electrical signal from the transmitted data; and

a display unit for displaying one or more electrical parameter based on the generated electrical signal,

wherein, the secondary coil is aligned co-axially with the primary coil and placed in proximity to achieve maximum efficiency in the electro-dynamic induction based wireless power and data transmission.

2. The pluggable display device of claim 1, wherein the secondary coil is configured for uni-directional power transmission at low frequency band which comprises receiving power from the primary coil.

3. The pluggable display device of claim 1, wherein the secondary coil is configured for bi-directional data transmission at high frequency band which comprises:

receiving the one or more electrical parameter from the primary coil; and sending user communication signal to the primary coil.

4. The pluggable display device of claim 1, wherein the control unit further comprises:

a signal processing unit for modulating or demodulating the transmitted power and data;

a rectifier for rectifying the transmitted power; and

a voltage regulator for regulating the rectified power based on power requirement of the display unit.

5. The pluggable display device of claim 1, wherein the display unit comprises at least one selected from the group of a LCD screen, a LED screen, and an EINK screen.

6. The pluggable display device of claim 1 further comprises a mounting means for engaging the display device with the measuring unit and co-axially aligning the secondary coil with the primary coil.

7. The pluggable display device of claim 6, wherein the mounting means comprises at least one selected from a plurality of permanent magnets and a magnetic strip.

8. The pluggable display device of claim 1 further comprises a memory unit for storing the one or more electrical parameter.