Patent Application
20170259927
The disclosure generally relates to electronics systems, and more particularly to the design of a fault detection system for electronics systems in aircraft.
Modern aircraft may utilize various electronics systems, such as ice detection systems, deicing systems, air data probes, etc. Various electronics systems may include a heating element. A voltage potential may be applied across the heating element to draw current through the heating element and convert electrical energy to thermal energy.
A fault detection system may comprise a current transformer; a current-to-voltage converter (CVC) configured to receive a secondary current from the current transformer; a voltage level detector configured to receive a signal from the CVC; and a controllable switch, the controllable switch in electronic communication with the voltage level detector.
In various embodiments, the CVC may include a resistor in electronic communication with the current transformer. The secondary current may flow through the resistor. The signal may comprise a secondary voltage signal. A secondary voltage may exist across the resistor in response to the secondary current, the secondary voltage signal corresponding to the secondary voltage, and the secondary current being based on a difference between a first current and a second current. The voltage level detector may receive the secondary voltage signal from the CVC. The voltage level detector may determine if the secondary voltage is greater than a threshold value. The controllable switch may be moved to an open position in response to the secondary voltage being greater than the threshold value. The controllable switch may be coupled, in series, between the heating element and the current transformer.
An ice detection system may comprise a current transformer, the current transformer configured to provide a means of comparing a first current and a second current, wherein the second current is less than the first current in response to a fault in the ice detection system; a heating element comprising a first resistance; a controllable switch in electronic communication with the current transformer and in electronic communication with the heating element, the controllable switch connected in series with the current transformer and the heating element, wherein the first current is configured to flow from the current transformer, through the controllable switch, and through the heating element; a current-to-voltage converter (CVC) in electronic communication with the current transformer; and a voltage level detector in electronic communication with the CVC and in electronic communication with the controllable switch.
In various embodiments, the CVC may comprise a resistor configured to receive a secondary current from the current transformer, the secondary current being based on a difference between the first current and the second current. A secondary voltage may exist across the resistor. The voltage level detector may be configured to receive the secondary voltage from the CVC. The voltage level detector may be configured to determine if the secondary voltage is greater than a threshold value. The controllable switch may be configured to move to an open position in response to the secondary voltage being greater than the threshold value. The controllable switch may receive a disable signal in response to the secondary voltage being greater than the threshold value. The voltage level detector may be configured to send a fault signal in response to the secondary voltage being greater than the threshold value. The CVC may include an analog-to-digital converter (ADC) configured to convert the secondary voltage from an analog signal to a digital signal.
A method of detecting a fault in a heating circuit may comprise: generating, by a current transformer, a secondary current, the secondary current being based on a difference between a first current and a second current; measuring a voltage across a resistor, the secondary current flowing through the resistor; determining if the voltage is greater than a threshold value; and sending a disable signal to a controllable switch in response to the voltage being greater than the threshold value, wherein the controllable switch moves to an open position in response to receiving the disable signal.
In various embodiments, the current transformer may be connected in series with a heating element. A magnitude of the secondary current may be zero in response to a first alternating current being equal to a second alternating current.
The foregoing features, elements, steps, or methods may be combined in various combinations without exclusivity, unless expressly indicated herein otherwise. These features, elements, steps, or methods as well as the operation of the disclosed embodiments will become more apparent in light of the following description and accompanying drawings.
The subject matter of the present disclosure is particularly pointed out and distinctly claimed in the concluding portion of the specification. A more complete understanding of the present disclosure, however, may best be obtained by referring to the detailed description and claims when considered in connection with the drawing figures, wherein like numerals denote like elements.
The detailed description of various embodiments herein makes reference to the accompanying drawings, which show various embodiments by way of illustration. While these various embodiments are described in sufficient detail to enable those skilled in the art to practice the inventions, it should be understood that other embodiments may be realized and that logical, chemical and mechanical changes may be made without departing from the spirit and scope of the inventions. Thus, the detailed description herein is presented for purposes of illustration only and not of limitation. For example, the steps recited in any of the method or process descriptions may be executed in any order and are not necessarily limited to the order presented. Furthermore, any reference to singular includes plural embodiments, and any reference to more than one component or step may include a singular embodiment or step. Also, any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full and/or any other possible attachment option. Additionally, any reference to without contact (or similar phrases) may also include reduced contact or minimal contact.
In the detailed description herein, references to “one embodiment”, “an embodiment”, “various embodiments”, etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. After reading the description, it will be apparent to one skilled in the relevant art(s) how to implement the disclosure in alternative embodiments.
System program instructions and/or controller instructions may be loaded onto a non-transitory, tangible computer-readable medium having instructions stored thereon that, in response to execution by a controller, cause the controller to perform various operations. The term “non-transitory” is to be understood to remove only propagating transitory signals per se from the claim scope and does not relinquish rights to all standard computer-readable media that are not only propagating transitory signals per se. Stated another way, the meaning of the term “non-transitory computer-readable medium” and “non-transitory computer-readable storage medium” should be construed to exclude only those types of transitory computer-readable media which were found in In Re Nuijten to fall outside the scope of patentable subject matter under 35 U.S.C. §101.
As used herein, “electronic communication” means communication of electronic signals with physical coupling (e.g., “electrical communication” or “electrically coupled”) or without physical coupling and via an electromagnetic field (e.g., “inductive communication” or “inductively coupled” or “inductive coupling”).
Modern aircraft may utilize various electronics systems, such as ice detection systems, deicing systems, and air data probes, for example. Various electronics systems may include a heater circuit comprising a heating element. A voltage potential may be applied across the heating element (for example, a resistance element such as an electrical resistor) to draw current through the heating element and to convert electrical energy to thermal energy. Such heater circuits may fault (short circuit) to a chassis ground and fail. Typical heater circuits may not be able to detect this fault condition. Thus, an electronics system having a heater circuit with a ground fault detection system is provided herein, in accordance with various embodiments. The current going to the heater circuit is compared with the current going out the heater circuit. A fault is detected based upon this comparison.
With reference to
In various embodiments, fault detection system 14 may include a current transformer 52. A first current (i.e., current magnitude IAC HIGH) may flow through current transformer 52. A second current (i.e., current magnitude IAC LOW) may flow through current transformer 52. The first current and the second current may be out of phase by one hundred and eighty degrees (180°). Current transformer 52 may produce a secondary current comprising a magnitude ISEC. Current magnitude ISEC may be proportional to the current magnitude in the transformer primary, in accordance with equation 1:
I
SEC
=K(IAC-HIGH−IAC-LOW) EQ. 1
The current magnitude ISEC may be greater than zero in response to IAC HIGH being greater than or less than IAC HIGH. The current magnitude ISEC may be zero in response to IAC HIGH being equal to IAC HIGH. K may be a constant which may depend on the design of current transformer 52. In this manner, ISEC may be based upon a difference between IAC HIGH and IAC LOW. Stated another way, ISEC may be based upon a difference between the first current and the second current.
In various embodiments, fault detection system 14 may include a controllable switch 40. Controllable switch 40 may be connected in series with current transformer 52 and heating element 50. Controllable switch 40 may receive inputs wherein controllable switch 40 moves from a closed position, as illustrated in
In various embodiments, fault detection system 14 may include voltage level detector 30. In various embodiments, voltage level detector 30 may comprise a controller. Voltage level detector 30 may receive a signal (also referred to herein as a secondary voltage signal) 28. Voltage level detector 30 may determine if signal 28 is greater than a threshold value. The threshold value may be a predetermined threshold value. The threshold value may be determined such that noise in the current flowing through heating circuit 12 tends not be detected as a fault. For example, the threshold value may comprise between ten millivolts and two hundred millivolts (0.01-0.2 V). Voltage level detector 30 may send signal 32 to controllable switch 40 in response to signal 28 being greater than the threshold value.
In various embodiments, fault detection system 14 may include current-to-voltage converter (CVC) 20. CVC 20 may determine if a current (i.e., IAC HIGH) flowing through current transformer 52 is equal to a current (i.e., IAC LOW) flowing through current transformer 52. Generally, current flowing into heating circuit 12 (e.g., via terminal AC HIGH) is equal to current flowing out heating circuit 12 (e.g., via terminal AC LOW).
With reference to
With reference to
In various embodiments, in response to a fault being detected in heating circuit 12, a fault signal 34 may be sent from voltage level detector 30. Fault signal 34 may be sent to a controller in a vehicle such as an aircraft. Fault signal 34 may be used to indicate to an operator or an aircraft system that a fault has been detected in heating circuit 12. In various embodiments, fault signal 34 may comprise a Boolean data type.
With reference to
With reference to
In various embodiments, with additional reference to
Benefits, other advantages, and solutions to problems have been described herein with regard to specific embodiments. Furthermore, the connecting lines shown in the various figures contained herein are intended to represent various functional relationships and/or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may be present in a practical system. However, the benefits, advantages, solutions to problems, and any elements that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the inventions. The scope of the inventions is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” Moreover, where a phrase similar to “at least one of A, B, or C” is used in the claims, it is intended that the phrase be interpreted to mean that A alone may be present in an embodiment, B alone may be present in an embodiment, C alone may be present in an embodiment, or that any combination of the elements A, B and C may be present in a single embodiment; for example, A and B, A and C, B and C, or A and B and C. Different cross-hatching is used throughout the figures to denote different parts but not necessarily to denote the same or different materials.
Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. 112(f) unless the element is expressly recited using the phrase “means for.” As used herein, the terms “comprises”, “comprising”, or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
