Abstract:
Methods and apparatus for an imaging system are provided. The imaging system includes a gantry having a stationary member coupled to a rotating member. The rotating member has an opened area proximate an axis about which the rotating member rotates. An x-ray source provided on the rotating member. An x-ray detector may be disposed on the rotating member and configured to receive x-rays from the x-ray source. A rotary transformer having circumferentially disposed primary and secondary windings may form part of a contactless power transfer system that rotates the rotatable portion of the gantry at very high speeds, the primary winding being disposed on the stationary member and the secondary winding being disposed on the rotating member.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This invention generally relates to the transmission of data and power across a rotating interface, and more particularly, to an apparatus that can transmit both power and data across the rotating interface without requiring brushes or other contacts. 
         [0002]    High-voltage power transformers are used in a variety of applications, such as in baggage scanner systems, computed tomography (CT) systems, wind turbines, and other electronic systems. CT systems are often used to obtain non-invasive sectional images of test objects, particularly internal images of human tissue for medical analysis and treatment. Current baggage scanner systems and CT systems position the test object, such as luggage or a patient, on a conveyor belt or table within a central aperture of a rotating frame (e.g., gantry) which is supported by a stationary frame. The rotating frame includes an x-ray source and a detector array positioned on opposite sides of the aperture, both of which rotate around the test object being imaged. At each of several angular positions along the rotational path (also referred to as “projections”), the x-ray source emits a beam that passes through the test object, is attenuated by the test object, and is received by the detector array. The x-ray source utilizes high-voltage power to generate the x-ray beams. 
         [0003]    Each detector element in the detector array produces a separate electrical signal indicative of the attenuated x-ray beam intensity. The electrical signals from all of the detector elements are collected and processed by circuitry mounted on the rotating frame to produce a projection data set at each gantry position or projection angle. Projection data sets are obtained from different gantry angles during one revolution of the x-ray source and detector array. The projection data sets are then processed by a computer to reconstruct the projection data sets into, for example, an image of a bag or a CT image of a patient. 
         [0004]    The circuitry mounted on the rotating frame is powered by low-voltage power, while the x-ray source is powered by high-voltage power. Conventional rotating gantry based systems utilize a brush and slip ring mechanism to transfer power at a relatively low-voltage between the stationary and rotating portions of the gantry frame. The rotating gantry portion has an inverter and high-voltage tank mounted thereon and connected to the brush and slip ring mechanism. The inverter and high-voltage tank including transformer, rectifier, and filter capacitance components step-up the voltage from the low-voltage, transferred through the brush and slip ring mechanism, to the high-voltage needed to drive the x-ray source. The transformer in the high-voltage tank produces a high-voltage AC signal that is converted to a high-voltage DC signal by rectifier circuits inside the high-voltage tank. 
         [0005]    Conventional rotating gantry based scanner systems have experienced certain disadvantages. The high-voltage tank and inverter on the rotating gantry portion increases the weight, volume and complexity of the system. Furthermore, the brush and slip ring mechanisms (that are typically used to carry appreciable current) are subject to reduced reliability, maintenance problems, and electrical noise generation, which interfere with sensitive electronics. As systems are developed that rotate faster, it becomes desirable to reduce the volume and weight of the rotating components. 
         [0006]    To eliminate slip ring brushes, rotary transformers can be used to transfer power in a contactless manner to the rotating gantry. However, the voltage and current in rotating transformers used to transfer power in CT imaging systems are quite considerable. For example, a 150 KW imaging system may have a rotary transformer that operates at approximately 300 volts and 500 amperes and that generates a considerable amount of electrical noise. Extraordinary steps are required to keep this noise out of data being transmitted across the gantry. For example, some CT imaging systems utilize optical signals for data transmission. In one such system, an optical signal is injected into a mirror groove that is configured to bounce the optical signal in both directions across the gantry, from a 0 degree location to a ±180 degree location. An optical stylus is inserted into the groove from an opposite side of the gantry to pick up the optical signal. Another such system uses a plurality of optical transmitters that are multiplexed. The optical transmitters pass across a stationary shoe with an optical detector as the gantry rotates, and the optical transmitters are synchronized to the changing location of the detector. These configurations are relatively costly and complicated. 
         [0007]    A scanner apparatus is needed that addresses the above concerns and other problems experienced in the past, and that is relatively inexpensive and simple. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0008]    There is thus provided, in one embodiment of the present invention, an apparatus for transmitting power and data. The apparatus includes a first rotary transformer portion and a second rotatable transformer portion separated by a gap and relatively rotatable around a common axis. The rotary transformer has a first differential winding on the first rotary transformer portion and a second differential winding on the second rotary transformer portion. The first differential winding and the second differential winding are relatively rotatable with respect to each other while remaining separated from one another. The rotary transformer is configured to transfer power from the first rotary transformer portion to the second rotary transformer portion. The rotary transformer also has a first data transmitter on the first rotary transformer portion, a second data transmitter on the second rotary transformer portion, a first data receiver on the second rotary transformer portion and operatively coupled to the first data transmitter to provide data transmission in a first direction across the gap, and a second data receiver on the first rotary transformer portion and operatively coupled to the second data transmitter to provide data transmission in a second direction across the gap. 
         [0009]    In another embodiment of the present invention, there is provided a computed tomography (CT) imaging system. The CT imaging system includes a gantry defining a boundary between a stationary portion of the CT imaging system and a rotating portion of the CT imaging system. The gantry has a stationary member coupled to a rotatable member. The rotatable member has an opened area proximate an axis about which the rotatable member rotates. The rotatable member further includes a rotatable transformer portion and the stationary member further includes a stationary transformer portion. The CT imaging device includes a radiation source and a radiation detector array opposite one another on the rotatable member. Also included is electronic circuitry in the rotating portion of the CT imaging system. The electronic circuitry includes a data acquisition system operatively coupled to the radiation detector array. The CT imaging system also includes a stationary transformer portion on the stationary member and a rotatable transformer portion on the rotatable member. The stationary transformer portion and rotatable transformer portion are separated by a gap. Also, the rotary transformer has a stationary differential winding on the stationary transformer portion and a rotatable differential winding on the rotatable transformer portion, wherein the rotatable differential winding is configured to rotate while remaining separated from the stationary differential winding, and the rotatable transformer configured to transfer power from the stationary portion of the CT imaging system to the electronic circuitry in the rotating portion of the imaging system. Further included is a rotatable data transmitter on or mounted to the rotatable transformer portion, a stationary data transmitter on or mounted to the stationary transformer portion, a rotatable data receiver on the rotatable transformer portion and operatively coupled to the stationary data transmitter to provide data transmission in a first direction across the gap, and a stationary data receiver on the stationary transformer portion and operatively coupled to the rotatable data transmitter to provide data transmission in a second direction across the gap. 
         [0010]    In yet another embodiment of the present invention, there is provided a wind turbine comprising having a generator, a controller, a nacelle housing the generator and controller, a rotor having a hub and at least one blade, the rotor coupled to the generator by a shaft and the hub including a blade pitch control and heater for the at least one blade or blades, and a controller configured to communicate data with sensors and controls within the wind turbine, including the blade pitch control and heater. Also included is a rotatable transformer portion mounted on the shaft and a stationary transformer portion separated by a gap, a rotary transformer having a stationary differential winding on the stationary transformer portion and a rotatable differential winding on the rotatable transformer portion, wherein the rotary transformer is configured to allow the stationary differential winding and the rotatable differential winding to rotate while remaining separated from one another, and to supply power to the blade pitch control and heater. Further includes is a rotatable data transmitter on the rotatable transformer portion on the shaft and a stationary data transmitter on the stationary transformer portion, a rotatable data receiver on the rotatable transformer portion and operatively coupled to the stationary data transmitter to provide data transmission in a first direction across the gap, and a stationary data receiver on the stationary transformer portion and operatively coupled to the rotatable data transmitter to provide data transmission in a second direction across the gap. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a front partial cut-away view of an apparatus for transmitting power and data in accordance with an exemplary embodiment of the invention. 
           [0012]      FIG. 2  is a side view taken along a slice  2 - 2  of  FIG. 1 . 
           [0013]      FIG. 3  is a block schematic diagram showing additional details of an electronic coupling used in one embodiment of the present invention. 
           [0014]      FIG. 4  is a more detailed block schematic diagram of one embodiment of the present invention. 
           [0015]      FIG. 5  is an exemplary schematic representation of an apparatus having electrical coupling between a data receiver and a data transmitter employing a transmission line antenna. 
           [0016]      FIG. 6  is a cross-sectional view of an exemplary embodiment of a stripline pair. 
           [0017]      FIG. 7  is a partial cut-away drawing showing a first rotary transformer portion and a second rotary transformer portion that comprise substantially concentric cylinders. 
           [0018]      FIG. 8  is an illustration of one winding of the rotary transformer included in the embodiment shown in  FIG. 1  and  FIG. 2 , showing the relationship of the winding and an E-core. 
           [0019]      FIG. 9  is a pictorial illustration of an exemplary computed tomography (CT) imaging system embodiment of the present invention. 
           [0020]      FIG. 10  is a block schematic diagram of the CT imaging system shown in  FIG. 9 . 
           [0021]      FIG. 11  is a pictorial schematic drawing of a wind turbine embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    The foregoing summary, as well as the following detailed description of certain embodiments of the present invention, will be better understood when read in conjunction with the appended drawings. To the extent that the figures illustrate diagrams of the functional blocks of various embodiments, the functional blocks are not necessarily indicative of the division between hardware circuitry. Thus, for example, one or more of the functional blocks (e.g., processors or memories) may be implemented in a single piece of hardware (e.g., a general purpose signal processor or a block of random access memory, hard disk, or the like). Similarly, the programs may be stand alone programs, may be incorporated as subroutines in an operating system, may be functions in an installed software package, and the like. It should be understood that the various embodiments are not limited to the arrangements and instrumentality shown in the drawings. 
         [0023]    As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural said elements or steps, unless such exclusion is explicitly stated. Furthermore, references to “one embodiment” of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments “comprising” or “having” an element or a plurality of elements having a particular property may include additional such elements not having that property. 
         [0024]      FIG. 1  is a front partial cut-away view of an apparatus  100  for transmitting power and data in accordance with an exemplary embodiment of the invention, and  FIG. 2  is a side view taken along a slice  2 - 2  of  FIG. 1 . The apparatus  100  has two rotary transformer  107  portions  102  and  104  separated by a gap  106  and relatively rotatable around a common axis z. Rotary transformer  107  also comprises a first differential winding  108  on first rotary transformer portion  102  and a second differential winding  110  on second rotary transformer portion  104 . First differential winding  108  and second differential winding  110  (not shown in  FIG. 1  or  FIG. 2 , but visible in  FIG. 8 ) are rotatable relative to second transformer portion  104  and first transformer portion  102 , respectively, while remaining separated from one another. Windings  108  and  110  themselves are shown and described elsewhere herein, but in one embodiment of the present invention are wound in E-cores  112  and  114  with the open portion of the “E”s facing one another. (The “open portion” of an “E” is the right portion. The left portion is a “closed portion.”) The term “E-core” should be understood as encompassing not only cores with two grooves between the three horizontal lines of the “E,” but also cores that have more than two grooves and more than three horizontal lines to the “E.” 
         [0025]    Apparatus  100  further includes a first data transmitter  116  on first rotary transformer portion  102 . Although first data transmitter  116  includes additional electrical components, in one embodiment, first data transmitter  116  comprises a differential stripline transmission line  118  that is wrapped around first rotary transformer portion  102 . A differential voltage is applied to first data transmitter  116  to transmit to a first data receiver  120  on second rotary transformer portion  104  across gap  106 . Similarly, apparatus  100  further includes a second data transmitter  122  on second rotary transformer portion  104 , and data is transmitted to second data receiver  124  on first rotary transformer portion  102  across gap  106 . Data receivers  120  and  124  can comprise one or two (or a plurality of) pickup antennas or pads cantilevered a distance, for example, about a millimeter, above corresponding transmission line transmitters. Transmission lines such as transmission line  118  can comprise a single transmission strip or a dual transmission slip. Differentially wound coils are described in U.S. Pat. No. 7,054,411, entitled “Multichannel contactless power transfer system for a computed tomography system”, which issued on May 30, 2006 to Katcha et al., and U.S. Pat. No. 7,197,113, entitled “Contactless power transfer system,” which issued on Mar. 27, 2007 to Katcha et al., both patents being assigned to General Electric Co., Schenectady, N.Y. 
         [0026]    In some CT imaging systems, apparatus  100  is used to couple data signals and power across a gantry. It should be noted that even though a large amount of power (e.g., 150 KW) can be transferred, there is very little if any interference to data voltages of less than 1 V on the stripline transmission lines used for data transmission and reception. In general, the differential windings on the E-core, i.e., windings wrapped around the center or an inside leg of the E-core, results in leakage fields that are closely contained, despite the high voltages and currents and the leakage inductance resulting from the open gap between the windings. The addition of resonant capacitors in the windings of the transformer can further reduce any noise that may remain in data channels. 
         [0027]    In some embodiments, first data receiver  120  and first data transmitter  122  are coupled optically rather than electrically and second data receiver  124  and second data transmitter  122  are coupled optically rather than electrically. In another embodiment, first data receiver  120  and first data transmitter  116  are coupled magnetically rather than electrically and second data receiver  124  and second data transmitter  122  are coupled magnetically rather than electrically. However, in other embodiments, first data receiver  120  and first data transmitter  116  are coupled electrically and second data receiver  124  and second data transmitter  122  are coupled electrically in a manner such as that described in conjunction with  FIGS. 1 and 2 . 
         [0028]      FIG. 3  is a block schematic diagram showing additional details of an electronic coupling used in one embodiment of the present invention. Inverter  300 , resonant components  302 , and filter  304  serve to couple an AC voltage to transformer winding  110 , while rectifier  306  serves to couple an induced voltage on transformer winding  108  to load  308 .  FIG. 4  is a more detailed block schematic diagram of one embodiment of the present invention. Once the detailed description provided herein is thoroughly understood, the selection of components  402 , X 1 , C 1 , C 2 , C 3 , C 4 , C 5 , C 6 , L 2 , L 3 , L 4 , and R 1 , as well as other components shown in  FIG. 4 , can be left as a design choice to one of ordinary skill in the art of electronic power circuit design. 
         [0029]      FIG. 5  is an exemplary schematic representation of an apparatus having electrical coupling between a data receiver (e.g., first data receiver  120 ) and a data transmitter (e.g., first data transmitter  116 ) employing a transmission line antenna. To avoid abrupt phase changes that might generate data errors, transmission line  40  comprises respective individual segments  50  and  60  each having a respective first end  52  and  62  and a respective second end  54  and  64 . Each individual segment  50  and  60  has a respective electrical length chosen so that a signal applied at each respective first end  52  and  62  has a predetermined time-delay upon arrival at each respective second end  54  and  64 . It will be appreciated that if the respective electrical lengths for segments  50  and  60  are substantially similar to one another, e.g., close to 180 degrees, the above-described segment arrangement results in the serial data stream signal arriving at each respective second end having a substantially similar time delay relative to one another. 
         [0030]    The data signal can be readily split and amplified by a suitable driving circuit  70  comprising amplifiers  72  and  74  and optional matching resistors  76  and  78  having a predetermined resistance value selected to match the impedance characteristics of the respective transmission line segments. Similarly, each respective second end  54  and  64  is respectively connected to termination resistors  80  and  82  having a predetermined resistance value chosen to minimize reflection of energy in individual transmission line segments  50  and  60 . Other arrangements may be employed, which although having differences in time delay between individual segments, such time-delay differences can be tolerated depending on the specific application. For example, amplifier  74  and matching resistor  78  can be connected to second end  64  in lieu of first end  62  and termination resistor  82  connected to first end  62  in lieu of second end  64 . In this case although a predetermined time delay exists between respective first and second ends, such delay could be acceptable in certain applications. Further, although driving circuit  70  is shown as comprising a pair of amplifiers, it will be apparent that a suitable single amplifier can be employed equally effectively for driving individual segments  50  and  60 . For example, each respective first end  52  and  62  can be readily connected in parallel to receive the output signal of a single amplifier, and thus, in this case, driving circuit  70  comprises a single amplifier. Thus, a transmission line, such as a center tapped transmission line, having respective segments electrically connected in parallel to a single amplifier can be optionally employed. 
         [0031]    Individual segments  50  and  60  in one embodiment are arranged so that respective first ends of any two consecutive segments are substantially adjacent to one another and respective second ends of any two consecutive segments are substantially adjacent to one another. The gap size between any two consecutive segments should be small relative to a wavelength corresponding to the data rate. This arrangement allows for avoiding time-delay discontinuities between any of the respective individual segments encircling the rotating frame, and for effective coupling operation between the transmission line and the receiver at all rotation angles. As shown in  FIG. 5 , each of the two individual segments  50  and  60  can be designed to subtend a respective angle of about 180 degrees around the rotating frame. A data receiver (e.g., first data receiver  120 ) is held sufficiently near segments  50  and  60  for establishing radio coupling therebetween. As used herein the expression “radio coupling” refers to noncontactive transfer of energy by electromagnetic radiation at radio frequencies. 
         [0032]    In some embodiments of the present invention, each individual segment  50  and  60  comprises two striplines fed in a differential manner. The differential feeding of the stripline pair in segment  50  and the differential feeding of the stripline pair in segment  60  results in substantial containment of fields and a reduction in emission of high frequency interference. The stripline pairs can be etched on flexible board, resulting in an inexpensive and simple data coupling mechanism. An exemplary differential stripline embodiment is shown in  FIG. 6 , which shows a cross-sectional view of a stripline pair of segment  50 . Segment  50  comprises a first conductor  202  and a second conductor  203  deposited or etched onto an insulating substrate  204  and a conductive ground plane  206 . The selection of this or another suitable differential stripline embodiment is a design choice that may be made by one of ordinary skill in the art. 
         [0033]    Thus, in some embodiments of the present invention, the first data receiver, the second data receiver, the first data transmitter and the second data transmitter can comprise sectioned, circular stripline antennas. In some of these embodiments, the sections of the circular stripline antennas are phased to reduce or eliminate phase discontinuities in coupled data signals. A description of a stripline antenna can be found in U.S. Pat. No. 5,579,357, entitled “Transmission line using a phase splitter for high data rate communication in a computerized tomography system,” issued Nov. 26, 1996 to Daniel D. Harrison and assigned to General Electric Company, Schenectady, N.Y. 
         [0034]    Referring again to  FIG. 2 , first rotary transformer portion  102  and second rotary transformer portion  104  substantially face one another. The data and power couplings in this case are in an axial or z direction. The data and power couplings do not require shielding. In another embodiment, and as shown in  FIG. 7 , first rotary transformer portion  102  and second rotary transformer portion  104  can comprise substantially concentric cylinders, in which the data and power couplings are oriented in a radial or r direction. 
         [0035]    In some embodiments of the present invention, either first rotary transformer portion  102  or second rotary transformer portion  104  is constrained to be stationary. “Stationary” in this sense implies little or no rotational movement around at least the z axis as observed by an observer on the ground. For example, where apparatus  100  is used in a gantry of a CT imaging apparatus, one portion of the apparatus is stationary with respect to the ground while the other portion is considered to be rotating. 
         [0036]      FIG. 8  is another illustration of one winding  108  or  110 , showing relationship to an E-core  112  or  114 . Rotary transformer  107  comprises a pair of windings  108  and  110  each wound on a separate E-core  112  or  114 , respectively, with open sides of the E-cores  112  and  114  facing one another. If there is no gap between E-cores  112  and  114 , windings  108  and  110  would be enclosed within the abutting E-cores  112  and  114 . The winding shown in  FIG. 68  is a differential winding because the winding goes around the middle leg  115  of the E-core  112  or  114 . Although a winding with only one turn is shown, the various embodiments of the invention are not limited to requiring windings to have only one turn. The number of turns can be a design choice that can be made by one of ordinary skill in the art. 
         [0037]      FIG. 9  is a pictorial illustration of an exemplary computed tomography (CT) imaging system  600  in accordance with an embodiment of the present invention, and  FIG. 10  is a block schematic diagram of CT imaging system  600  of  FIG. 9 . CT imaging system  600  includes a gantry  602  defining a boundary  604  between a stationary portion  606  of CT imaging system  600  and a rotatable portion  608  of CT imaging system  600 . Gantry  602  includes a rotatable transformer portion  102  (see  FIG. 1  and  FIG. 2 ) and a stationary transformer portion  104  that is constrained to be “stationary” by its mounting. The designations “first” and “second” can be associated with “stationary” and “rotatable” arbitrarily, provided the association is consistent throughout. Note, however, that the first and the second data receivers are on the opposite sides of the first and the second data transmitter, respectively. Also, “stationary,” as used herein, means stationary rather than rotating about the same axis as the corresponding rotatable component as viewed from an observer standing on the floor. A rotatable radiation source  610  such as an x-ray tube is provided on gantry  602  as well as a rotatable radiation detector array  612  opposite radiation source  610 . Radiation source  610  and radiation detector array  612  rotate with rotatable transformer portion  102  when gantry  602  rotates. Rotatable portion  608  of CT imaging system  600  also includes electronic circuitry  614 , including a data acquisition system  616  operatively coupled to radiation detector array  612 . CT imaging system  600  further includes a stationary transformer portion  104 , wherein stationary transformer portion  104  and rotatable transformer portion  102  are separated by a gap  106  (see  FIG. 1  and  FIG. 2 ). 
         [0038]    Rotary transformer  107  in CT imaging system  600  includes a stationary differential winding  110  on stationary transformer portion  104  and a rotatable differential winding  108  on rotatable transformer portion  102  (See  FIGS. 1  and  FIG. 2 ). Rotatable differential winding  108  is configured to rotate while remaining separated from stationary differential winding  110 , and rotatable transformer  107  is configured to transfer power from stationary portion  606  of CT imaging system  600  to electronic circuitry  614  in rotatable portion  608  of CT imaging system  600 . A rotatable data transmitter  116  is on rotatable transformer portion  102  and a stationary data transmitter  122  is on stationary transformer portion  104 . Also, a rotatable data receiver  124  is on rotatable transformer portion  102  and is operatively coupled to stationary data transmitter  122  to provide data transmission in a first direction across gap  106 , and a stationary data receiver  120  is on stationary transformer portion  104  and operatively coupled to rotatable data transmitter  116  to provide data transmission in a second direction across gap  106 . Transmitters and receivers use one of an electric, magnetic, or optical signal to transmit data in a contactless manner. As in the case of apparatus  100 , CT imaging system  600  may have transformer portions that substantially face each other or that comprise concentric cylinders. 
         [0039]    Some of the embodiments of CT imaging system  600  are medical imaging systems. Other embodiments of CT imaging system  600  are industrial or security scanning systems, such as a bomb detection system for baggage. The embodiments may be defined by the type of firmware or software that is included in CT imaging system  600 . In the case of a medical imaging system, the software or firmware in CT imaging system  600  is configured to analyze biological structures and/or organs. A CT imaging system  600  for bomb detection in luggage includes software configured to analyze the content of baggage for bombs and/or explosive material. 
         [0040]      FIG. 11  is a pictorial schematic drawing of a wind turbine  700  constructed in accordance with an embodiment of the present invention. Wind turbine  700  includes a nacelle  701  housing a generator  702  and various electrical, electronic, and mechanical components. Among the electronic components is a controller  704  that is configured to communicate data with various sensors and controls within wind turbine  700  and with an external computer that is used to monitor and control the operation of wind turbine  700 . In use, wind turbine  700  may be mounted on a tall, vertical tower (not shown in the Figures) so as to permit rotation of rotor  706  about an essentially horizontal axis without interference to blade or blades  708  from the ground and other obstacles. Rotor  706  includes a rotatable shaft  707  to turn generator  702  when a wind sufficient to operate wind turbine  700  is available. 
         [0041]    Controller  704  operates pitch blade control and heater  710  that can turn nacelle  701  in various directions along a vertical axis to orient blades  708  in a proper direction for capturing energy from the wind or to stop or control wind turbine  700  as required. In addition, wind turbine  700  includes a blade pitch control and heater  710  in a hub  712  of rotor  706  to which blade or blades  708  are attached. Blade pitch control and heater  710  operates under control of wind turbine controller  704 . Controller  704  is further configured to send power and control signals to blade pitch control and heater  710  to de-ice blades  708  as necessary and to pitch blades  708 . An apparatus for transmitting power and data, such as apparatus  100  described above in respect to  FIG. 1  and  FIG. 2  may be used and has a stationary portion and a rotating portion, the latter mounted on shaft  707  and having wires running through center hole of shaft  707  to hub  712  to provide power and control signals to blade pitch control and heater  710 . This arrangement permits transfer of power and data without twisting of wires to the blade pitch control and heater  710 . Bidirectional data transfer may be used to allow controller  704  to receive and process data from sensors located in hub  712  and/or on and/or in blade or blades  708 . 
         [0042]    Referring to  FIGS. 1 and 7 , wind turbine  700  may include a power and data transmission apparatus  100  wherein first data receiver  120  and first data transmitter  116  are coupled electrically and second data receiver  124  and second data transmitter  122  are also coupled electrically. The designations “first” and “second” can be associated with “stationary” and “rotatable” arbitrarily, provided the association is consistent throughout. Note, however, that the first and the second data receivers are on the opposite sides of the first and the second data transmitter, respectively. In addition, referring to  FIG. 3  as well, wind turbine  700  may include a power and data transmission apparatus  100  wherein the first data receiver  120 , the second data receiver  124 , the first data transmitter  116  and the second data transmitter  122  comprise sectioned, circular antennas. The sections of the circular antennas can be phased in the manner described herein to reduce or eliminate phase discontinuities in coupled data signals. Also, in some embodiments of wind turbine  700  and referring to  FIG. 8 , rotary transformer  107  can comprise a pair of E-cores  112  and  114  with open sides of the E-cores facing one another. 
         [0043]    In variations of the embodiments, it will be appreciated that the stationary transmitter may be placed on an outer circumference of the stationary transformer portion and the rotating transmitter may be placed on an inner circumference of the rotating transformer portion, with the receivers moved accordingly. The transmitters and receivers may also be placed on surfaces facing each other. Also, the transmitters and receivers may use any one of electrical, magnetic or optical signals, or a combination thereof, to transmit between rotating and stationary portions in a contactless manner. 
         [0044]    At least one technical effect of the various embodiments is to provide, using contactless means, high speed bi-directional communication links along with high power transformer coupling in a reduced spatial volume and at reduced cost and complexity as compared to devices or combinations of devices used today for similar purposes. In addition, a high level of reliability for contactless power transfer and bi-directional communications is achieved. 
         [0045]    It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. While the dimensions and types of materials described herein are intended to define the parameters of the invention, they are by no means limiting and are exemplary embodiments. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. § 112, sixth paragraph, unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.