Browse Topic: Relays
A design is presented for an electro-mechanical switchgear, intended for reconfiguring the windings of an electric machine whilst in operation. Specifically, the design is developed for integration onto an in-wheel automotive motor. The motor features 6 phase fractions, which can be reconfigured by the switchgear between series-star or parallel-star arrangements, thereby doubling the torque or speed range of the electric machine. The switchgear has a mass of only 1.8kg – around one tenth of the equivalent 2-speed transmission which might otherwise be employed to achieve a similar effect. As well as the extended operating envelope, the reconfigurable winding motor offers benefits in efficiency and power density. The mechanical solution presented is expected to achieve efficiency and cost advantages over equivalent semiconductor-based solutions, which are practical barriers to adoption in automotive applications. The design uses only mechanical contacts and a single actuator, thereby offering a convincing techno-economic proposition. Furthermore, it is shown that a torque interruption time of <30ms is feasible for reconfiguration events using the mechanical relay; whilst this is longer than for a semiconductor-based solution, it is likely to be imperceptible to vehicle passengers and not affect the driver experience. The project outcomes show that mechanical relay designs can in fact provide a competitive all-round solution for this functionality, making reconfigurable motors a realistic prospect for automotive applications.
A regulated hybrid-electric power sharing architecture was developed and tested for VTOL applications. In this architecture, there are two power supply branches and one load. The first branch draws power from an engine-generator, and it has additional components of an AC-DC rectifier, a DC-DC buck converter, and a power diode. The second branch draws power from a battery, and it has additional components of a solid-state relay, a DC-DC boost converter, and a power diode. Any specified ratio of battery-to-engine power can be achieved with this architecture. Testing on the full range of power share ratios was conducted at a low load power of 300W. The key conclusions are that: (1) regulated power sharing is feasible between an AC supply and a DC battery, including the extremes of all engine and no battery to all battery and no engine, (2) a specified power share ratio can be achieved both in steady-state and transient conditions, and (3) there is a delay in achieving a specified power share ratio, caused not by the power plant, but rather by the change in RPM of the rotor.
Viasat, Inc. Washington, D.C. 202-383-5074
MIT engineers are taking a modular approach with a LEGO-like design for a stackable, reconfigurable artificial intelligence chip. The design comprises alternating layers of sensing and processing elements, along with light-emitting diodes (LED) that allow for the chip’s layers to communicate optically. Other modular chip designs employ conventional wiring to relay signals between layers. Such intricate connections are difficult if not impossible to sever and rewire, making such stackable designs not reconfigurable.
This SAE Standard establishes test methods for the evaluation of devices and equipment in vehicles against transient transmission by coupling via lines other than the power supply lines. The test methods demonstrates the immunity of the instrument, device, or equipment to coupled fast transient disturbances, such as those caused by switching of inductive loads, relay contact bouncing, etc. Four test methods are presented in SAE J1113-12: the capacitive coupling clamp (CCC) method the direct capacitive coupling (DCC) method the inductive coupling clamp (ICC) method the capacitive/inductive coupling (CIC) method
MIT engineers are taking a modular approach with a LEGO-like design for a stackable, reconfigurable artificial intelligence chip. The design comprises alternating layers of sensing and processing elements, along with light-emitting diodes (LED) that allow for the chip’s layers to communicate optically. Other modular chip designs employ conventional wiring to relay signals between layers. Such intricate connections are difficult if not impossible to sever and rewire, making such stackable designs not reconfigurable.
To solve the problems of power quality and phase-links of the high-speed and heavy-load electrified railways power supply system, this paper presents a traveling wave-based directional protection for continuous co-phase autotransformer traction power supply system (TPSS). Basically, phase-mode transformation is used to decouple the transient fault signals to get aerial mode components and then the forward and inverse traveling wave is obtained by calculating the aerial mode components. The variational mode decomposition (VMD) method has no mode confusion and can obtain the accurate instantaneous amplitude and frequency, so it is used to extract the intrinsic mode function (IMF) components, which are further calculated to get the modulus maxima. Two relays at the ends of the protected catenary are used to detect internal and external faults. Consequently, a continuous co-phase traction autotransformer TPSS is modeled in PSCAD/EMTDC, and various faults are simulated to verify the proposed method. Numerous simulation results indicate that the protection method is effective and immune to fault locations, fault resistances, and fault types.
Missions for small unmanned aircraft (Group 1 and Group 2) include over-the-hill surveillance and providing airborne communications relay points. Greater endurance is almost universally desired by operators to increase the time spent on-station performing the mission and reduce the number and frequency of takeoffs and landings.
The authors have developed a wireless sensor suite for rotorcraft Generator Control Unit (GCU) and Main Power Relay (MPR) health monitoring. This sensor suite monitors for changes in component characteristics, temperature, vibration extremes, voltage surges, and other factors that will indicate the unit is close to the end of its service life. The sensor suite logs event/triggered or time sequenced/snapshot "smart data" for prognostic and diagnostic estimations, then wirelessly transmits the logged data to maintenance personnel and/or a Health Monitoring and Usage System (HUMS) mounted on the rotorcraft. The system assists in diagnosis and corrective maintenance by capturing data at the time of a fault and aiding in its visualization. This system also assists with Condition Based Maintenance (CBM) by calculating prognostic signatures that indicate to maintenance personnel when failure of select electrical system components is imminent.
Switching controls are those that can switch between control or plant modes to perform their functions. They have the advantage of being simpler to design than an equivalent control system with a single mode. However, the transients between those modes can introduce steps or overshootings in the state variables, and this can degrade the performance or even damage the control or the plant. So, the smoothing of such transients is vital for their reliability and mantainability. This is can be of extreme importance in the aerospace and automotive fields, plenty of switchings between manual and autopilot modes via relays, or among gears via clutches, for example. In this work, we present a first strategy for smoothing transients in switching controls of aerospace and automotive systems. To do that, we review the literature, present and adopt a criterion to determine the coefficients of a control system which should optimize the trajectory of the control signal during the switching between two modes. The chosen criteria are the classical integral of the time times the square of the error (ITSE), and the integral of the time times the module of the error (ITME). Effectively, each transition will be done by a subsystem specific for it, according to the selected criterion. The system will be chosen from relevant cases of the literature. The simulations will be made in MATRIXx@ or MATLAB@. The results obtained so far suggest that the proposed strategy effectively reduces the steps or overshootings in the transients between those switching modes and can contribute for the reliability and mantainability of aerospace and automotive systems.
In response to the requirements of the Space-Based Relay Study (SBRS) undertaken by NASA in 2013, as well as the Integrated Radio and Optical Communications (iROC) project being conducted by NASA Glenn Research Center (GRC) beginning in 2012, a calculation procedure was required to rapidly assess the operation of optical communication links originating from within deep space (in particular, from around Mars in the case of iROC), as well as within the near-Earth scenarios of LEO and GEO (in the case of SBRS). Such an assessment included the specification of the design components of the optical system to achieve reliable communications as prescribed by one or several metrics that indicate overall system operation. Additionally, it was also desired to be able to dynamically evaluate such optical link operation as the satellite/earth orbital positions evolve during the mission lifetime.
Efficient support of planetary surface missions typically requires an orbiting asset that acts as a relay point to/from Earth. Orbital relay passes are normally 5 to 15 minutes in duration over any specific landed site. When multiple landed assets are co-located or near-located in the same coverage circle of a single relay orbiter, their telecom relay support opportunities will overlap. This will be the case with cooperative lander missions, a lander-rover operations pair, distributed intelligent lander missions, and future deployment of multiple equipment components for support of complex sample return or manned operations. In these situations, the capability of simultaneous support to multiple landers is very valuable for mission performance and operations flexibility. This technology work enables simultaneous telecom support to multiple landers (Mars, Titan, Europa), and provides single-radio, multi-mode support to Entry, Descent & Landing (EDL) and emergency operations (e.g., demodulation + Open Loop Recording).
In response to the requirements of the Space-Based Relay Study (SBRS) undertaken by NASA in 2013, as well as the Integrated Radio and Optical Communications (iROC) project being conducted by NASA Glenn Research Center (GRC) beginning in 2012, a calculation procedure was required to rapidly assess the operation of optical communication links originating from within deep space (in particular, from around Mars in the case of iROC), as well as within the near-Earth scenarios of LEO (low-Earth orbit) and GEO (geostationary Earth orbit) in the case of SBRS. Such an assessment included the specification of the design components of the optical system to achieve reliable communications as prescribed by one or several metrics that indicate overall system operation.
In order to transmit communications through Earth’s atmosphere, satellites and space vehicles need radio equipment that can operate at higher frequencies than on Earth. These higher frequencies, until recently, have demanded mechanical switches in radio relays. Unfortunately, the mechanical switches had some problems with frequency routing, which inspired NASA to seek more rugged, reliable solutions.
Mars rovers and other landers typically use UHF relay to return their science and engineering data to Earth. Direct-To-Earth (DTE) communications are typically used for commanding. If future UHF relay capability becomes diminished, Mars landers may be forced to use DTE communications to meet their data return requirements. An augmented DTE capability with a high-gain antenna and a higher-power transmitter are required to support the relatively high data volume returned in a typical mission. The research for this innovation has developed an antenna architecture that can support such an augmented DTE capability. This antenna architecture comprises an array of microstrip patch subarrays fed by a waveguide corporate feed network, producing a net gain of 30 dBic at the array input.
When NASA and other agencies send landers to Mars and other planets, they rely on existing orbiters to relay the data during the critical entry, descent, and landing (EDL) phase. The current orbiters are aging and there are no current NASA plans to replace them. Future landers have a critical challenge to communicate during a very risky mission phase. The InSight mission will land on Mars in September 2016 with no direct-to-Earth radio link. Instead, Insight expects the Mars Reconnaissance Orbiter (MRO) to be fully functional and placed in an orbit to be in view of the EDL time and place. MRO will take many hours to play back the data to Earth, leaving the project staff without knowledge if their valuable spacecraft has made it safely.
This paper will illustrate how the increasing electrical power demands of military and aerospace applications can continue to successfully be met by high performance electromechanical relays. To meet these higher demands engineering compatibility must be properly understood between the intended application demands and relay switching performance parameters. With high performance electromechanical relays continuing to play a critical part in military and aerospace applications it is more important than ever that engineers capture all of the electrical power switching requirements. A critical area within powering military and aerospace systems is relay life when capacitive load switching. Capacitive loads generate high current levels that are transient in duration and often adversely affect the relay lifespan at the component level and the military or aerospace application reliability at the systems level. Often these transients, while brief in nature, can dramatically exceed the steady-state switching ratings for the contacts in a high performance electromechanical relay. In this paper practical examples of inrush current reduction of capacitive transient high current loads and corresponding increase of relay contact life rating will be reviewed and explored in detail. By adapting the relay circuit design with current inrush reduction components and techniques the user can ensure a properly rated relay will meet the capacitive load switching requirements of the end application. When capacitive loads are properly identified and contained within the relay capabilities a higher degree of application-relay compatibility can be achieved. There are many positive payoffs including increased switching lifespan, functionality, and reliability that enhance the customer experiences under demanding military and aerospace conditions.
The assembling accuracy of two contactors during the relay switch production is an important factor affecting the quality of relay. An embedded machine vision quality Inspection system has been developed for electric relay production line inspection. The proposed system can provide online feedback on the quality of the relays by measuring the distance of the gap between the contacts of them. Two CMOS imaging sensors are operated for image acquisition and the parallel working mode is realized under dual-channel mode. A red light illumination system has been adopted to eliminate the imaging noise from the reflection of the surfaces of copper sheet. Before the test, the features areas in the image of same type relay is selected as template and saved in the computer. During the inspection procedure, a rotation invariance detection scheme based on circular projection matching algorithm has been used for fast recognizing and locating detected object with the help of these feature areas. According to the corresponding position relation among internal components of relay, the contactors edge detection area can be locked. Then a coarse-to-fine edge detection algorithm has been applied to accurately locate the edge position of the contactors. The gap distance of two contacts of the detected rely can be calculated according to the ratio between the image size and the actual physical size of the corresponding imaging scene. Finally the detected data information is transferred to a data processing center by communication system. The proposed system show great potential in large volume manufacturing of electric relays.
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