A CONTACTLESS POWER STATION FOR CELLULAR BATTERY CHARGER

A Contactless Power Station (CLPS) is a new breakthrough to transmit power without wires in electronic devices such as cellular phones. Power transfer capability of a CPLS system can be increased if the system is designed to operate under resonance condition. The power transfer is then controlled by controlling the inverter frequency. In order to ensure that the power transfer is maximum, a maximum power point tracker is employed to control the CLPS. Several simulated and experimental results are included

Influence of system integration and packaging on its inductive power link for an integrated wireless neural interface

Journal ArticleIn an integrated wireless neural interface based on the Utah electrode array, the implanted electronics are supplied with power through inductive coupling between two coils. This inductive link is affected by conductive and dielectric materials and media surrounding the implant coil. In this study, the influences of the integration of an implant coil on a silicon-based IC and electrode array, thin-film Parylene-C encapsulation, and physiological medium surrounding the coil were investigated systematically and quantitatively by empirical measurements. A few embodiments of implant coils with different geometrical parameters were made with a diameter of ∼5.5 mm by winding fine wire with a diameter of approximately 50 μm. The parasitic influences affecting the inductive link were empirically investigated by measuring the electrical properties of coils in different configurations and in different media. The distance of power transmission between the transmit and receive coils was measured when the receive coil was in air and immersed in phosphate buffered saline solution to simulate an implanted physiological environment. The results from this study quantitatively address the influences of factors such as device integration, encapsulation, and implantation on its inductive power link, and suggest how to maximize the efficiency in power transmission for such neural interface devices powered inductively

Cryogenic mechanisms for scanning and interchange of the Fabry-Perot interferometers in the ISO long wavelength spectrometer

The Infrared Space Observatory (ISO) is an ESA cornerstone mission for infrared astronomy. Schedules for launch in 1993, its four scientific instruments will provide unprecedented sensitivity and spectral resolution at wavelengths which are inaccessible using ground-based techniques. One of these, the Long Wavelength Spectrometer (LWS), will operate in the 45 to 180 micron region (Emery et. al., 1985) and features two Fabry-Perot interferometers mounted on an interchange mechanism. The entire payload module of the spacecraft, comprising the 60 cm telescope and the four focal plane instruments, is maintained at 2 to 4 K by an onboard supply of liquid helium. The mechanical design and testing of the cryogenic interferometer and interchange mechanisms are described

Design and Analyses of a MEMS Based Resonant Magnetometer

A novel design of a MEMS torsional resonant magnetometer based on Lorentz force is presented and fabricated. The magnetometer consists of a silicon resonator, torsional beam, excitation coil, capacitance plates and glass substrate. Working in a resonant condition, the sensor’s vibration amplitude is converted into the sensing capacitance change, which reflects the outside magnetic flux-density. Based on the simulation, the key structure parameters are optimized and the air damping effect is estimated. The test results of the prototype are in accordance with the simulation results of the designed model. The resolution of the magnetometer can reach 30 nT. The test results indicate its sensitivity of more than 400 mV/μT when operating in a 10 Pa vacuum environment

Improvements to secondary windings of Tesla transformers

Impulse excitation of the tuned primary circuit of a Tesla transformer generates a voltage and current response in the similarly tuned secondary circuit that contains both a fundamental component and a series of multiple higher-order modes. This paper investigates the most significant of these modes, in order to demonstrate a design approach that, when applied to the secondary winding, can bring about a reduction in the higher-order modes without significantly affecting the fundamental term. The resulting process leads to an improved spectral purity of the transformer output, making it better suited than existing conventional designs for application in electronic warfare and other high-power systems

Electrical stress monitoring of distribution transformers using smart grid techniques

Electrical stresses that distribution transformers rated 16 kVA up to 2 MVA are subjected to can often cause premature transformer failures. In this study, research related to the development of cost effective bushing embedded sensors that can measure the electrical stresses on the MV side of distribution transformers has been conducted. An embedded screen in a specially designed 24 kV bushing was used for both power frequency and transient voltage measurements. Observed results showed that the screen-based bushing capacitive voltage divider offered results that are consistent with those of a commercial capacitive voltage divider for power frequency voltages as low as 1 kV up to 24 kV. Impulse voltage measurements were consistent with those of a wideband resistive divider for voltages lower than 60 kV. Voltages higher than 60 kV revealed non-linear behaviour which increases as the 150 kV BIL rating of a 22 kV transformer is reached. A nonlinear resistor added to ATPdraw simulations was able to compensate for the observed nonlinearity. PD tests conducted on the prototype bushing showed that the designed prototype had surface discharges which are affected by the positioning of the bushing screen. A Rogowski coil embedded in the same bushing was used for the measurement of both power frequency and transient currents. Measured coil parameters used in ATPdraw simulations produced results that were consistent with the output of the Rogowski coils when measuring 8/20 s current impulses. Numerical integration of the Rogowski coil output voltages was successfully used in the recovery of both power frequency and measured impulse currents. The Rogowski coil sensitivity is affected by both coil dimensions and terminating resistance. The designed prototype bushing opens up opportunities for performing stress monitoring on the MV side of distribution transformers

Remote power delivery for hybrid integrated Bio-implantable Electrical Stimulation System

Bio-implantable devices such as heart pacers, gastric pacers and drug-delivery systems require power for carrying out their intended functions. These devices are usually powered through a battery implanted with the system or are wired to an external power source. In this work, a remote power delivery system (RPDS) is considered as a means to charge rechargeable batteries that power a Bio-implanted Electrical Stimulation System (BESS). A loosely coupled inductive power transmitter and receiver system has been designed to recharge batteries for a bio-implanted gastric pacer. The transmitter coil is periodically worn around the waist. The receiver coil, rechargeable batteries, battery-charging chip and the chip containing electrical stimulation circuitry form a bio-implanted hybrid integrated microsystem. The link efficiency between a transmitter coil and the implanted receiver coil when the diameters are markedly different is analyzed. A design methodology for RPDS is proposed based on the load and voltage required at the load. An analytical model is developed with the help of simple Matlab coding. A full wave rectifier with a voltage doubler circuit is used for the conversion of ac voltage to the required dc voltage. This dc voltage supplies power to a battery charging chip which is used to safely and appropriately charge a rechargeable Li-ion battery. For an input supply voltage of 17.67 V rms, operating frequency of 20 kHz and radial coplanar displacement between the coil axes of 7.5 inches, the maximum dc voltage and power obtained across a 65Ω load resistor are 9.65 V and 1.33 W respectively. For a radial coplanar displacement between the coil axes of 6 inches, a 3.7 V nominal, 150 mAh polymer lithium ion battery has been successfully charged in 1 hour and 40 minutes from an initial voltage of 3.39 V to 4.12 V with an input voltage of 19.81 V rms at 20 kHz. An attempt has been made to model coil parasitics at high frequency. Variations in the load power as a function of frequency and radial coplanar displacement of the axes are examined. Design strategies to optimize power delivery with given geometric constraints are considered

Quantum Electromechanics on Silicon Nitride Nanomembranes

Radiation pressure has recently been used to effectively couple the quantum motion of mechanical elements to the fields of optical or microwave light. Integration of all three degrees of freedom—mechanical, optical and microwave—would enable a quantum interconnect between microwave and optical quantum systems. We present a platform based on silicon nitride nanomembranes for integrating superconducting microwave circuits with planar acoustic and optical devices such as phononic and photonic crystals. Using planar capacitors with vacuum gaps of 60 nm and spiral inductor coils of micron pitch we realize microwave resonant circuits with large electromechanical coupling to planar acoustic structures of nanoscale dimensions and femtoFarad motional capacitance. Using this enhanced coupling, we demonstrate microwave backaction cooling of the 4.48 MHz mechanical resonance of a nanobeam to an occupancy as low as 0.32. These results indicate the viability of silicon nitride nanomembranes as an all-in-one substrate for quantum electro-opto-mechanical experiments

A rack-mounted precision waveguide-below-cutoff attenuator with an absolute electronic readout

A coaxial precision waveguide-below-cutoff attenuator is described which uses an absolute (unambiguous) electronic digital readout of displacement in inches in addition to the usual gear driven mechanical counter-dial readout in decibels. The attenuator is rack-mountable and has the input and output RF connectors in a fixed position. The attenuation rate for 55, 50, and 30 MHz operation is given along with a discussion of sources of errors. In addition, information is included to aid the user in making adjustments on the attenuator should it be damaged or disassembled for any reason