Patent Description:
Ram air turbines are generally used in aircraft to provide supplemental and/or emergency power to the aircraft by utilizing air flow to rotate a turbine. Ram air turbines may provide electrical power, hydraulic power, or both. Electrical ram air turbines produce electrical power by transferring the rotational energy of the turbine to a power conversion device, such as a generator. The power generated by the generator may be alternating current (AC) power and may be used to power aircraft components that are typically operated using AC power. An AC power system is described in <CIT>; it discloses in particular a system for stabilizing an electric system of an aircraft, having a power stabilizing control section to control conversion of electric power in power converter sections, and to charge and discharge direct current power supply.

Described herein is a system for providing alternating current (AC) power to an aircraft component as defined by claim <NUM>.

In any of the foregoing embodiments, the controller is further configured to cause the RAT to deploy and to cause the inverter to provide the AC power to the aircraft component simultaneously.

Any of the foregoing embodiments may also include a first switch coupled between the inverter and the aircraft component and a second switch coupled between the RAT and the aircraft component, and wherein the controller is configured to cause the inverter to provide the AC power to the aircraft component by closing the first switch, and to cause the RAT to provide the AC power to the aircraft component by closing the second switch.

In any of the foregoing embodiments, the low speed condition corresponds to deployment of landing gear of a corresponding aircraft.

In any of the foregoing embodiments, the controller is further configured to identify a peak load condition corresponding to a condition in which the aircraft component is requesting increased AC power, and to control the inverter and the RAT to provide the AC power simultaneously in response to identifying the peak load condition.

In any of the foregoing embodiments, the controller is further configured to identify a light load condition corresponding to a condition in which the aircraft component is requesting reduced AC power, and to control the RAT to provided power to charge the energy storage device in response to identifying the light load condition.

Also disclosed is a method for providing alternating current (AC) power to an aircraft component as defined by claim <NUM>.

The detailed description of exemplary embodiments herein makes reference to the accompanying drawings, which show exemplary embodiments by way of illustration and their best mode. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, it should be understood that other embodiments may be realized and that logical, chemical, and mechanical changes may be made without departing from the scope of the invention as defined by the claims. 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. Also, any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full and/or any other possible attachment option.

In various embodiments and with reference to <FIG>, an aircraft <NUM> may comprise wings <NUM> and a fuselage <NUM> having a nose <NUM>. A ram air turbine <NUM> may be located within the fuselage <NUM>, the nose <NUM>, or the wings <NUM>, and when desired, the ram air turbine <NUM> may be deployed into the path of airflow. The aircraft <NUM> may further include landing gear <NUM> that may be retractable (i.e., may be stowed in the fuselage <NUM> and then deployed prior to landing).

With reference to <FIG>, the ram air turbine <NUM>, or RAT <NUM>, may comprise a turbine <NUM> having one or more blades <NUM>. In various embodiments, the turbine <NUM> is coupled to a gearbox <NUM> which is also coupled to a strut <NUM>. For example, the strut <NUM> may be rotatably connected to the rear of the turbine <NUM> through a turbine shaft <NUM>.

In various embodiments, the strut <NUM> may be coupled to a power conversion adapter section <NUM>. The power conversion adapter section <NUM> may include a generator adapter section, however, the power conversion adapter section <NUM> is not limited to any particular power conversion device. Rotational energy from the turbine shaft <NUM> may transfer through the gearbox section <NUM> and a strut shaft <NUM> to the power conversion adapter section <NUM>.

The gearbox section <NUM> comprises a turbine shaft <NUM>. The turbine shaft <NUM> may be removably coupled to the turbine <NUM>, allowing the turbine shaft <NUM> to rotate with turbine blades <NUM>. The gearbox section <NUM> may include a bearing located at an opposite end of the turbine <NUM>. In such embodiments, the bearing may receive an end of the turbine shaft <NUM>.

Rotation of the turbine shaft <NUM> may result in power generation. In particular, the RAT <NUM> may generate alternating current (AC) power. The RAT may deploy in response to loss of aircraft standard power in order to provide electrical power to the aircraft <NUM> of <FIG>.

Turning now to <FIG>, a system <NUM> for providing power to aircraft components, such as AC power to an AC aircraft component <NUM> (such as a flight computer, critical heating elements such as pilot tube heaters, aisle lighting, or the like that is designed to be powered using AC power), is shown. The system <NUM> may be implemented in an aircraft, such as the aircraft <NUM> of <FIG>.

The system <NUM> includes the RAT <NUM>. Because the RAT <NUM> provides AC power, the RAT <NUM> may provide AC power to the AC aircraft component <NUM>.

The system <NUM> may further include an aircraft transformer rectifier unit (aircraft TRU) <NUM>. The aircraft TRU <NUM> may convert the AC power from the RAT <NUM> into direct current (DC) power for powering one or more DC aircraft component <NUM> (a component on an aircraft that is designed to be powered using DC power). The controller <NUM> may further control the power from the RAT <NUM> by controlling an AC power output contactor (RLC4, or fourth switch) <NUM> to provide the AC power to the aircraft TRU <NUM>.

In various embodiments and in response to loss of aircraft standard power, it may take the RAT <NUM> a certain amount of time, such as <NUM> second, <NUM> seconds, <NUM> seconds, or the like, to become fully deployed and provide the AC power. In that regard, the system <NUM> further includes an energy storage device <NUM>, such as a battery, a capacitor, a super capacitor, or another energy storage device. The energy storage device <NUM> is designed to store electrical energy and output the electrical energy as DC power.

The system <NUM> further includes a controller <NUM>. The controller <NUM> may include one or more logic devices such as one or more of a central processing unit (CPU), an accelerated processing unit (APU), a digital signal processor (DSP), a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), or the like. In various embodiments, the controller <NUM> may further include any non-transitory memory known in the art. The memory may store instructions usable by the logic device to perform operations.

The controller <NUM> may identify a point in time at which the aircraft loses aircraft standard power. In response to determining the loss of aircraft standard power, the controller <NUM> may cause the RAT <NUM> to deploy. The controller <NUM> may further control the power from the energy storage device <NUM> by controlling the DC power output contactor <NUM> to provide the DC power to the DC aircraft component <NUM>.

During the time of deployment of the RAT <NUM>, it may be desirable for the AC aircraft component <NUM> to receive power. In that regard, the system <NUM> further includes an inverter <NUM>. The inverter <NUM> is configured to receive DC power from the energy storage device <NUM> and to convert the DC power into AC power. In that regard, the controller <NUM> may simultaneously cause the RAT <NUM> to deploy and may cause the inverter <NUM> to provide the AC power to the AC aircraft component <NUM> in response to determining the loss of aircraft standard power.

The controller <NUM> is capable of identifying a time at which the RAT <NUM> is deployed and capable of providing the AC power. This condition is referred to as a sufficient wind speed condition. In response to identification of this time (i.e., in response to identification of the sufficient wind speed condition), the controller <NUM> is configured to control the inverter <NUM> to adjust a voltage, frequency, and phase to match the voltage, frequency, and phase of the AC power provided by the RAT <NUM>. In response to determining that the inverter <NUM> is providing AC power that matches that of the RAT <NUM> (and in response to determining that the RAT can provide the AC power), the controller <NUM> is configured to cause a momentary paralleling of AC power from the inverter <NUM> and the RAT <NUM>. The inverter <NUM> is configured to then cease providing the AC power to the AC aircraft component <NUM> and to cause the RAT <NUM> to begin providing the AC power to the AC aircraft component <NUM>.

The system <NUM> may include a plurality of switches including a first switch <NUM>, a second switch <NUM>, a third switch <NUM>, and a fourth switch <NUM>. The controller <NUM> may be coupled to each of the switches <NUM>, <NUM>, <NUM>, <NUM> and may control the switches <NUM>, <NUM>, <NUM> based on desirable operation. For example, the first switch <NUM> may be located between the inverter <NUM> and the AC aircraft component <NUM>, the second switch <NUM> may be located between the RAT <NUM> and the AC aircraft component <NUM>, the third switch <NUM> may be located between the energy storage device <NUM> and the DC aircraft component <NUM>, and the fourth switch <NUM> may be located between the RAT <NUM> and the aircraft TRU <NUM>.

The controller <NUM> may cause the inverter <NUM> to provide the AC power to the AC aircraft component <NUM> by causing the first switch <NUM> to close, and may cause the inverter <NUM> to cease providing the AC power to the AC aircraft component <NUM> by causing the first switch <NUM> to open. Likewise, the controller <NUM> may cause the RAT <NUM> to provide the AC power to the AC aircraft component <NUM> by causing the second switch <NUM> to close, and may cause the RAT <NUM> to cease providing the AC power to the AC aircraft component <NUM> by causing the second switch <NUM> to open. The controller <NUM> may likewise control the third switch <NUM> to control power distribution between the energy storage device <NUM> and the DC aircraft component <NUM>. The controller <NUM> may likewise control the fourth switch <NUM> to control power distribution between the RAT <NUM> and the aircraft TRU <NUM>.

The system <NUM> includes a RAT power sensor <NUM> and may further include a plurality of other sensors including a RAT pre-switch power sensor <NUM>, and an inverter power sensor <NUM>. The RAT power sensor <NUM> is configured to detect a detected RAT power corresponding to an amount of AC power output by the RAT <NUM>, preferably in response to the second switch <NUM> being closed. The RAT pre-switch power sensor <NUM> may detect a detected RAT power corresponding to an amount of AC power output by the RAT <NUM> in any condition. The inverter power sensor <NUM> may detect an amount of AC power output by the inverter <NUM>. Any of the power sensors <NUM>, <NUM>, <NUM> may detect additional data corresponding to the power such as voltage, amperage, frequency, and phase of the AC power.

The controller <NUM> may identify a time at which the RAT <NUM> is capable of providing the AC power by monitoring the RAT pre-switch power sensor <NUM>. For example, in response to the RAT pre-switch power sensor <NUM> detecting a power level that is above a threshold power level, the controller <NUM> may determine that the RAT <NUM> is capable of providing the AC power to power the AC aircraft component <NUM>.

The controller <NUM> may likewise use the data detected by the power sensors <NUM>, <NUM>, <NUM> to control the features of the AC power output by the inverter <NUM> to match the features of the AC power output by the RAT <NUM>. For example, the controller <NUM> may identify the voltage, frequency, and phase of the power sensed by the RAT pre-switch power sensor <NUM> and may control the inverter <NUM> to match the voltage, frequency, and phase. The controller <NUM> may further control the voltage, frequency, and phase of the AC power output by the inverter <NUM> based on feedback from the inverter power sensor <NUM>.

Referring to <FIG> and <FIG> and in some situations, wind speed received by the RAT <NUM> may be insufficient to provide the AC power to the AC aircraft component <NUM>. Such a situation may be referred to as a low speed condition, indicating that the RAT <NUM> receives insufficient wind speed to provide the AC power to the AC aircraft component <NUM>. For example, a low speed condition may be caused by deployment of the landing gear <NUM> as the landing gear <NUM> may disrupt the wind received by the RAT <NUM> during deployment.

In response to identifying the low speed condition, the controller <NUM> may close the first switch <NUM>, causing the inverter <NUM> to provide the AC power to the AC aircraft component <NUM>. The controller <NUM> may simultaneously open the second switch <NUM> to prevent the RAT <NUM> from providing the AC power to the AC aircraft component <NUM>. In various embodiments, the controller <NUM> may control the inverter <NUM> to match the voltage, frequency, and phase of the AC power provided by the RAT <NUM> prior to at least one of closing the first switch <NUM> or opening the second switch <NUM>.

The controller <NUM> is configured to identify the low speed condition based on data detected by the RAT power sensor <NUM>. For example, if the RAT power sensor <NUM> detects a power value that is less than a threshold power value, then the controller <NUM> may determine that a low speed condition exists and may control the inverter <NUM> to provide the AC power to the AC aircraft component <NUM>.

The controller <NUM> is configured to identify a sufficient wind speed condition corresponding to a condition in which the RAT <NUM> receives sufficient wind speed to provide the AC power to the AC aircraft component <NUM>. For example, the sufficient wind speed condition may occur upon full deployment of the RAT <NUM>, may occur upon full deployment of the landing gear <NUM> (e.g., if the landing gear <NUM> fails to interrupt the wind speed received by the RAT <NUM> when fully deployed), or the like. The controller <NUM> is configured to cause the RAT <NUM> to provide the AC power to the AC aircraft component <NUM> in response to identifying the sufficient wind speed condition. In various embodiments, the controller <NUM> may identify the sufficient wind speed condition based on data detected by the RAT pre-switch power sensor <NUM> (or the RAT power sensor <NUM>).

In various embodiments and returning reference to <FIG>, the controller <NUM> may identify a peak load condition corresponding to a condition in which the AC aircraft component <NUM> is requesting an increased amount of AC power. For example, the peak load condition may correspond to a time in which the AC aircraft component <NUM> is requesting more power than the RAT <NUM> is capable of providing. As another example, the peak load condition may simply correspond to an increased power request from the AC aircraft component <NUM>. In response to identifying the peak load condition, the controller <NUM> may cause the first switch <NUM> and the second switch <NUM> to close to allow both the RAT <NUM> and the inverter <NUM> to power the AC aircraft component <NUM>.

In various embodiments, the controller <NUM> may identify a light load condition corresponding to a condition in which the AC aircraft component <NUM> is requesting a reduced amount of AC power. For example, the AC aircraft component <NUM> may be requesting an amount of AC power that is less than the amount of AC power provided by the RAT <NUM>. In response to identifying the light load condition, the controller <NUM> may control the RAT <NUM> to provide power to the energy storage device <NUM> in order to charge the energy storage device <NUM>. For example, the RAT <NUM> may provide AC power to the inverter <NUM>, which may convert the power into DC power and provide the DC power to the energy storage device for storage. In various embodiments, the controller may monitor the charge level of the energy storage device <NUM> and may cause the RAT <NUM> to cease providing power to charge the energy storage device <NUM> when the state of charge of the energy storage device reaches or exceeds a threshold state of charge level.

Turning to <FIG>, a method <NUM> for providing AC power to an aircraft component is shown. The method <NUM> may be performed by a system similar to the system <NUM> of <FIG>.

In block <NUM>, the controller is configured to detect or determine a loss of aircraft standard power. For example, the controller may lose communication with an aircraft computer, the controller may receive a signal indicating the loss of the aircraft standard power, or the like.

In block <NUM> and in response to determining the loss of aircraft standard power, the controller is configured to control the inverter to provide AC power to the AC aircraft component, and may control an energy storage device to provide DC power to a DC aircraft component.

In block <NUM> and in response to determining the loss of aircraft standard power, the controller may cause the RAT to deploy.

In block <NUM>, the controller is configured to control the inverter to cause the AC power output by the inverter to match the AC power that is output by the RAT. The controller is configured to cause the inverter to match the voltage, frequency, and phase of the AC power that is output by the RAT.

In block <NUM>, the controller is configured to control the RAT <NUM> and the inverter to switch such that the RAT provides the AC power to the AC aircraft component rather than the inverter providing the AC power.

In block <NUM>, the controller is configured to detect or identify a low speed condition. For example, the low speed condition may correspond to deployment of landing gear of a corresponding aircraft.

In block <NUM>, the controller is configured to control the inverter to provide the AC power to the AC aircraft component in response to determining the low speed condition.

In block <NUM>, the controller is configured to detect a sufficient wind speed condition. In response and in block <NUM>, the controller is configured to control the inverter to cause the AC power output by the inverter to match the AC power output by that of the RAT. In block <NUM>, the controller is configured to again control the AC power output to switch from the inverter to the RAT such that the RAT again provides the AC power to the AC aircraft component.

Turning to <FIG>, a method <NUM> for additional control of an emergency power system, such as the system <NUM> of <FIG>, is shown. In block <NUM>, a controller may detect or determine a peak load. The peak load may correspond to a situation in which a maximum amount of power is requested of a RAT. For example, the amount of power may be greater than the amount of power than the RAT can provide. In various embodiments, the RAT may be capable of providing the power during the peak load but the power request may be greater than normal.

In block <NUM> and in response to detecting or determining the peak load, the controller may control the RAT and an inverter to simultaneously provide AC power to an AC aircraft component. In various embodiments, this may include controlling the inverter to match the power output by the RAT, such as a voltage, frequency, and phase of the AC power.

In block <NUM>, the controller may detect a light load. The light load may correspond to a load that is lighter than normal. In various embodiments, the light load may correspond to any load that is less than the power output by the RAT.

In block <NUM> and in response to detecting the light load, the controller may control the RAT to provide power to the energy storage device for storage. For example, the controller may control the RAT to provide the power to the energy storage device via the inverter such that the inverter can convert the AC power from the RAT into DC power for storage.

Claim 1:
A system for providing alternating current, AC, power to an aircraft component, comprising:
a ram air turbine, RAT (<NUM>), configured to generate AC power;
an energy storage device (<NUM>) configured to output direct current, DC, power; an inverter (<NUM>) configured to convert the DC power from the energy storage device to the AC power;
a RAT power sensor (<NUM>) configured to detect a detected RAT power corresponding to an amount of AC power output by the RAT, the detected RAT power including a voltage, frequency and phase of the AC power that is output by the RAT; and
a controller (<NUM>) coupled to the RAT and the inverter,
wherein the controller (<NUM>) is configured to cause the inverter to provide the AC power to the aircraft component, and to control the RAT to provide the AC power to the aircraft component in response to determining that the RAT can provide the AC power, wherein the controller is further configured to identify a sufficient wind speed condition corresponding to a condition in which the RAT is capable of providing the AC power;
the controller being configured to control
the inverter to adjust the voltage, frequency, and phase to match the voltage, frequency, and phase of the AC power that is output by the RAT in response to identifying the sufficient wind speed condition; in response to determining that the inverter (<NUM>) is providing AC power that matches that of the RAT, the controller is configured to cause a momentary paralleling of the AC power from the inverter and the RAT, prior to causing the inverter to cease providing the AC power to the aircraft component and causing the RAT to begin providing the AC power to the aircraft component;
wherein the controller (<NUM>) is further configured to identify a low speed condition based on the detected RAT power, said low speed condition corresponding to a condition in which the RAT receives insufficient wind speed to provide the AC power to the aircraft component, and to cause the inverter to provide the AC power to the aircraft component in response to identifying the low speed condition.