Multi-phase motor drives, including induction motors and permanent magnet motors, are used in a wide variety of applications and offer fault-tolerant operation under faults in motor windings and converter switches. Symmetrical multi-fed drives based on three-phase modules are of special interest in safety critical applications. They offer simple control under a fault condition. However, even a single open-circuit fault of one switch or winding will cause complete interruption of a faulty module.
Rensselaer researchers have designed a convenient and inexpensive linear permanent magnet machine solution for transportation, conveyance, and other applications. When designed for short-strokes, the machine is very robust and rugged, and exhibits excellent performance characteristics such as very high thrust density, low ripples, and normal forces. Traditionally, linear PM machines had the armature windings in the translator and the PMs in the stator or vice-versa. This novel design allows both the field and armature excitations in the same part of the machine.
This technology relates to a liquid crystal display with refractive-index-matched electrode structures in its stacked components, which resulting in improved optical efficiency and lower power consumption over conventional LCDs.
The current high-growth nature of digital communications demands higher speed serial communication circuits. Present day technologies barely manage to keep up with the present need to communicate at high speeds, e.g. gigabit, terabit, and higher transmission speeds. Multiplexers are often used but have different input and output rates, which can cause jitter in the output signal.
This invention is directed to a method to improve the performance of stepper motor driven systems.Stepper motors are ubiquitous in modern office equipment and other machinery, yet little is published regarding their optimal use in open loop systems.Accurate control of a stepper motor is limited by the ability of the control system to approximate the actual motor and subsequently provide the correct instructions for achieving the actual desired movement with little or no error.Moving the motor to a specific position within a specified time period is difficult due to variations between motors
The cross-section of an X-ray phase shift image is a thousand times greater than that of X-ray attenuation in soft tissue over the diagnostic energy range implying phase imaging can achieve a much higher signal-to-noise ratio and substantially lower radiation dose than attenuation-based X-ray imaging. Grating interferometry is a state of the art X-ray imaging approach, which can simultaneously acquire information of X-ray phase-contrast, dark-field, and linear attenuation. This imaging modality can reveal subtle texture of tissues.
Computed Tomography (CT) is an important tool in diagnostic imaging. It plays a key role in diagnosis and intervention. Many advanced CT systems use wide detector arrays, multiple sources, andor very fast rotation speed, for important clinical applications (e.g., coronary artery and whole organ perfusion imaging). As a result, modern CT scanners are expensive and are typically used by major hospitals and clinics in developed countries. Over the past decades, CT systems or methods have been proposed assuming linear translation-based scanning.
Electrical impedance tomography (EIT) utilizes electrodes placed on the surface of a body to determine the complex conductivity distribution within the body. When using a voltage source in EIT, it is necessary to know both the applied voltage and the resulting current with high precision, which cannot be achieved with current systems.