Showing papers on "Voltage published in 1994"

High frequency power measurement

Abstract: A monitoring circuit (10) for an electrosurgical generator (11) has active and return output conductors. Voltage, current (24) and the inverse of current (24) picked up inductively are provided to adder circuits for summing the picked up voltage (20) and current (24) and computing the difference of the picked up voltage (20) and the current (24). Root mean square to direct current converters (26 and 28) signal RMS average values of the sum and difference. A microprocessor squares the values and applies them to a formula wherein the sum signals (22) have subtracted therefrom the difference signals (25); the results are divided by four to provide the root mean square of the power applied to the load (12). During desiccation the output is regulated in response to impedance to shut off output. A diagnostic circuit relates impedance load and output response during operation to a look up table or a microprocessor algorithm to calibrate. Feedback modifies the output when the adders determine the power applied to the load (12) in real time. A method has generator output to active and return conductors (14 and 15) and to inductive pick ups (16 and 17) for voltage and current (24), computes sum and differential values (25), changes root mean square to direct currents (24), squares the values and subtracts the differential from the summation, then divides the result finding the root mean square value of the power.

Wide-speed operation of interior permanent magnet synchronous motors with high-performance current regulator

Abstract: Interior permanent magnet synchronous motors can be applied to applications requiring wide-speed operation. The current vector control algorithm of an interior permanent magnet synchronous (IPM) motor for constant power operation over the base speed is proposed. As the available voltage controlling the armature current vector is small in the flux-weakening constant power region, the current vector sometimes becomes uncontrollable in transient operations because of the current regulator saturation. The high-performance current regulator is also proposed to improve the current responses in the flux-weakening region, which includes the decoupling current controller and the voltage command compensator. The control performances are confirmed by several drive tests with respect to the prototype IPM motor. >

Integrated Analog-To-Digital and Digital-To-Analog Converters

Abstract: List of Figures List of Tables List of Symbols Preface 1 The converter as a black box 2 Specifications of converters 3 High-speed A/D converters 4 High-speed D/A converters 5 High-resolution A/D converters 6 High-resolution D/A converters 7 Sample-and-hold amplifiers 8 Noise-shaping D/A conversion 9 Sigma-delta A/D conversion 10 Voltage and current references 11 Limitations of comparitors 12 Technology and device matching 13 Testing of D/A and A/D converters Index

A dynamic threshold voltage MOSFET (DTMOS) for ultra-low voltage operation

Abstract: To extend the lower bound of power supply to ultra-low voltages (06 V and below), we propose a dynamic-threshold voltage MOSFET (DTMOS) built on silicon-on-insulator (SOI) The threshold voltage of DTMOS drops as the gate voltage is raised, resulting in a much higher current drive than standard MOSFET at low power supply voltages On the other hand, V/sub t/ is high at V/sub gs/=0, therefore the leakage current is low We provide experimental results and 2-D device and mixed-mode simulations to analyze DTMOS and compare its performance with a standard MOSFET These results verify excellent DC inverter characteristics down to V/sub dd/=02 V, and good ring oscillator performance down to 03 V for DTMOS >

Apparatus and method for determining a charge of a battery

Abstract: In an electronic device powered by a battery, a method of determining a charge of the battery. Initially, a discharge curve specifying the battery's voltage as a function of time is determined. This discharge curve is calibrated according to actual measurements. Next, a battery state model is established. The battery state model is comprised of a number of discrete charge states. The probability of the actual battery's charge for a particular charge state is specified by the battery state model for each of the charge states. The battery's voltage is periodically measured. Based on the measured voltage and the discharge curve, a voltage probability distribution is computed. The battery discharge model is updated by applying Bayes theorem to the old discharge model and the voltage probability distribution. The charge of the battery based on a mean value of the battery discharge model is then displayed.

Analysis of the impact of pulse-width modulated inverter voltage waveforms on AC induction motors

Abstract: The purpose of this paper is not to reveal any new technology or major breakthrough pertaining to the impact of pulse-width modulated (PWM) adjustable speed drives operating on AC motors. Nor is it to discuss the merits of the various designs of the drives. The applications are also well defined. The area where much confusion still exists deals with the voltage waveform impact on the motor performance, hence, this is the central theme of the paper. The author has assumed that the traditional fundamental sine-wave voltage is (except for starting or outside influences) a steady-state condition, with a maximum and an RMS value, whereas the voltage waveform supplied by a PWM drive can have significant harmonics and transients which may alter the motor performance characteristics and life expectancy. The effects of the maximum voltage, rate of rise, switching frequencies, capacitors, resonance, and harmonics are all considered.

Apparatus for measuring voltages and currents using non-contacting sensors

Abstract: An apparatus for performing non-contacting measurements of the voltage, current and power levels of conductive elements such as wires, cables and the like includes an arrangement of capacitive sensors for generating a first current in response to variation in voltage of a conductive element. Each sensor is positioned in an electric field of the conductive element, and is thereby coupled to the conductive element through a coupling capacitance. A reference source drives the capacitive sensor arrangement at a reference frequency so as to induce the flow of a reference current therethrough. A measurement network is disposed to calculate the coupling capacitance based on a measurement of the reference current, and to then determine the voltage in the conductive element based on the first current and the coupling capacitance. Measurements of a composite current through single or multiple-element conductors may be effected using a similar procedure, wherein the composite current induces a measurement current to flow within a set of coils positioned in a predetermined manner proximate the conductor. In both current and voltage measurements a balancing procedure may be employed, in which a measurement signal is balanced by a feedback signal so as to improve accuracy and reduce the effects of stray coupling.

Method to operate an incoherently emitting radiation source having at least one dielectrically impeded electrode

Abstract: A method to operate an incoherently emitting radiation source, in particular a discharge lamp, which transmits UV, IR or VIS radiation. The discharge is generated by means of a train of voltage pulses, interrupted by idle times, inside a discharge vessel; electrodes dielectrically impaired on one or both ends can be used. By a suitable choice of the filling, the electrode configuration, the sparking distance, the type and thickness of the dielectrics, the time-dependent voltage amplitudes, and the pulse and idle times, efficiencies in UV generation of 65% and more are attained.

Image forming device

Abstract: PURPOSE:To use developer which is still quite usable till its life ends without discarding it, to reduce cost related to the developer, and simultaneously to reduce labor costs by recognizing the degree of the fatigue of the actual developer based on the ripple of a signal outputted from a developer concentration detection means CONSTITUTION:A developer fatigue measuring device is provided with the concentration detection means 29 detecting the toner concentration of the developer stirred by a stirring roller 27, and a control part judging the degree of the fatigue of the developer based on the output value from the means 29 so as to evaluate the life of the developer By stirring the developer by the roller 27, the ripple is cyclically generated in analog voltage outputted from a developer concentration measuring device(ATC) 29 being the concentration detection means At the time of using the developer, a ripple value from the ATC 29 is compared with an initial ripple value, and when the obtained ratio approximates to the ratio at the time when the life ends, an indicator is turned on so as to display that the life of the developer ends and accelerate the exchange of the developer When the ratio at the time when the life ends is attained, the machine is stopped

Secondary electrical power line parameter monitoring apparatus and system

Abstract: A system for unintrusively determining parameters such as current, voltage and power delivered through a service line to a customer for verifying accuracy of the customer's entrance meter. The system includes a sensor apparatus for monitoring voltage and current on the power line. A voltage clamp mechanism is disposed within a sensor housing such that an insulation piercing voltage sensor can be manually actuated to pierce the electrical insulation of the power line and contact the conductor. The sensor apparatus also includes a split-core current transformer fabricated to minimize the air gap between the split-core sections when the apparatus is closed about the power line. A pole unit is electrically connected to each sensor apparatus for monitoring the voltage and current, calculating the power consumed in kilowatt-hours and storing calculated kilowatt-hours in memory with an appropriate date/time stamp, for subsequent retrieval and comparison with the customer's entrance meter readings. Data retrieval is accomplished via a hand-held ground unit, such as a palm top computer, which communicates via infrared signals with the pole mounted unit.

A novel PWM scheme for a three-level voltage source inverter with GTO thyristors

Abstract: This paper presents a new PWM method for the three-level GTO inverters based on the space voltage vectors. With the proposed PWM method, we can minimize the harmonic components of the output voltage by avoiding the minimum pulse width limitation problem of the GTO thyristors and keeping the voltage balancing of the DC-link capacitors. The principle of the proposed PWM method and the voltage vector output sequences are described in detail. Computer simulation and experimental results verify that the proposed PWM method is suitable for high voltage and large capacity three-level GTO inverters applied to induction motor drives.

Battery monitoring and charging control unit

Abstract: A unit that can be a tiny module within a battery pack includes a microprocessor operating through onboard sensors and read circuitry to monitor battery current, voltage and temperature and to develop fast charge termination control data. Various termination schemes are available including negative delta V, dT/dt, dV/dt, absolute temperature, absolute voltage, and override timer. The microprocessor also operates to develop state of charge, percentage of capacity charge and other status data, to store such data along with setup and calibration data, in an EEPROM, to report data to a host periodically or when polled to and to operate automatically or at a user's request to initially perform and update a calibration as to actual battery capacity. During times when the pack is idle, the unit automatically reverts to a low-power mode in which measuring circuitry is deenergized but during such times, it operates periodically to compensate for self-discharge as a function of temperature. In the read circuitry, a ramp generator generates a linear ramp voltage that is compared with voltages proportional to battery voltage, supply voltage, battery current and temperature, using comparators connected to pins of a common port of the microprocessor and using a mask to obtain all readings from a single generation of the ramp. Voltage dividers of the read circuitry are so arranged as to permit accurate readings of current in either direction and to operate in a bridge configuration to obtain normalized measurements independent of ramp slope. Dynamic correction of readings and other features are also provided.

Method of repairing defective pixels

Abstract: Methods are disclosed by which the effects of a defective electromechanical pixel 20 having a beam 30 and a hinge 32,34 are mitigated. These methods may damage the hinge 32,34 or the beam 30 and comprise the step of applying a voltage sufficient to damage the hinge 32,34 or beam 30 of said electromechanical pixel 20 by mechanical overstress, thermal overstress, electrochemical reaction, or thermally induced chemical reaction. Other methods are also disclosed.

Direct observation of time-dependent space charge profiles in XLPE cable under high electric fields

Abstract: Space charge distribution was measured, applying an electric field of >1 MV/cm to 3 mm thick XLPE cable insulation. Improving the conventional pulse electro-acoustic method, a new method was developed to measure space charge when applying HV to cables. Under high field, hetero charges were formed soon after voltage application, followed by an injection from the cathode. Then intermittent injections of charge packets from the anode took place. The space charge distribution kept changing without becoming stabilized. A simulation was done assuming hysteresis of the injection characteristics. The observed intermittent injection near the anode was qualitatively reproduced using computer simulation. >

Packaging assembly with consolidated common voltage connections for integrated circuits

Abstract: An IC dice mounted on a substrate carrier wherein the IC dice is connected by a plurality of bonding wires to a plurality of corresponding bonding pads on the substrate carrier. The wire bonding layout configuration of the electronic device is improved in the present invention by providing centralized consolidated common voltage pads or bars such that the electric wires connecting the bonding pads to external interface contact points, e.g., the ball grid array (BGA) may be shortened. Additionally, the access widow for wire bonding to the IC dice may be broadened.

Low line harmonic ac to dc power supply

Abstract: The PWM control scheme is illustrated in conjunction with a power distribution control circuit (30), wherein the duty cycle of convverter (32) is suitably controlled by a number of feedback loops embodying various parameters, for example a voltage error signal, an average (eg. RMS) value of the input voltage (Vin). Circuit (30) comprises a rectifying circuit (42), a converter circuit (32), for example an AC-DC converter, a capacitor (C), an oscillator and PWM circuit (44), an error signal (46), a multiplier circuit (48), a differencing amplifier (50), and a synthesizing circuit (52). Circuit (30) appears as a resistive load to the line for feed PWM, a fixed load, and a fixed RMS input voltage. To stabilize the output voltage (Vout), the pulse width signal (44a) applied to converter suitably varies in proportion to both changes in the RMS value of the input voltage and the output voltage. The output voltage error signal applied to multiplier circuit by error circuit provides the correction value for Vout variations. The line RMS signal applied to multiplier by the line RMS filter circuit (52) compensates the PWM signal for variations in the RMS value of Vin. In this regard, the RMS loop modulator control signal may be advantageously normalized by Vrms (square) since Pin varies as Vin (square). Decreases in either the output error signal or the RMS signal increase the PWM value.

Dual voltage power supply

Abstract: A high efficiency power supply for producing two regulated output voltages (i.e. 3.3 and 5 volts) from an unregulated input voltage. The supply includes a 4-15 volt battery pack, a first (5.0 volt) output, a second (3.3 volt) output, and a ground. The positive terminal of the battery is connected directly to the second output. The 3.3 volt differential with ground is maintained by a voltage regulator that couples the negative terminal of the battery pack to ground (i.e. ground floats relative to the battery). A second voltage regulator couples the positive terminal of the battery pack to the first output, and maintains this first output at 5.0 volts relative to ground. This latter regulator is capable of boost operation, permitting a 5.0 volt output to be maintained even if the battery pack voltage is less than this value. Neither regulator includes a transformer, making the supply particularly well suited for use in miniaturized equipment, such as palmtop computers.

Compensation strategies for shunt active-filter control

Abstract: Compensation strategies for control of shunt active filters are compared in the paper. It is shown that the strategy based on unity-power factor control is appropriate when the supply voltage waveform of the plant where the active filter is connected shows significant distortion. As voltage distortion increases, this strategy provides compensated line current having lower harmonic distortion and RMS value with respect to the strategy generally used. This contributes to diminish the current and voltage distortion in networks. The unity-power factor compensation strategy conditions the current flowing in the plant where compensation is realized to fit the voltage waveform, thus reaching a unity power factor. Hence, the line current RMS value is minimum. The comparison of the strategies is performed by both Monte Carlo and ATP simulation. >

The influence of motor re-acceleration on voltage sags

Abstract: The assumption that a voltage sag is rectangular is not correct in a power system with large induction motor loads. The motors decelerate during the short circuit. After fault-clearing, they will accelerate again, drawing a high reactive current from the supply, causing a prolonged postfault voltage sag. This is aggravated by the removal of branches by the protection. The resulting shape of some voltage sags in an example power system is shown and discussed. For the example power system, a stochastic voltage sag table is determined. This table gives the expected number of sags of different depth and duration. The influence of faster protection and of reduced transformer impedance on the table is presented. A simple motor model is implemented in a method for including interruptions due to voltage sags in the reliability analysis of power systems. This model is presented briefly and used to show the influence of motor parameters on the number of sags that lead to an interruption of plant operation. >

Distributed current and voltage sampling function for an electric power monitoring unit

Abstract: A low voltage AC electric power monitoring system includes a processor which samples the current and circuit breaker system includes a processor which samples each of the current components at seventeen samples per cycle to obtain current samples representing a single period of the AC power signal. The processor samples the voltage component at different points in the voltage cycle over several cycles to obtain voltage samples representing a single period of the AC power signal.

Lightly-doped drain MOSFET with improved breakdown characteristics

Abstract: A high voltage integrated circuit (IC) has a passivation structure that shields the underlying circuit from the electrical effects of charge on the passivation structure. In one embodiment, the passivation structure comprises a silicon rich nitride layer in electrical contact with underlying circuit elements. The silicon rich nitride is highly resistive and permits only a negligible current between elements, but is conductive enough that charge on the surface of the passivation structure flows into the IC before the electric fields in the underlying circuit elements is significantly changed. In another embodiment, the passivation structure has two or more layers with a less conductive layer in contact with the underlying IC and overlying conductive layer which shields the IC from the effects of charge build up.

Electric power accumulating apparatus and electric power system

Abstract: An electric power accumulating apparatus utilizing a prallel and/or serial array of plural secondary batteries comprises means for detecting abnormality in each of the secondary batteries, means for electrically detaching the output terminals of the secondary battery showing abnormality and, in case of serial connection, shortcircuiting the terminals to which the secondary battery showing abnormality has been connected, and means for compensating the voltage corresponding to the detached battery, thereby providing improved safety, stable output and extended service lives of the secondary batteries.

Hybrid alternator with voltage regulator

Abstract: A hybrid alternator includes a stator (10) and a rotor (20), with the rotor (20) having longitudinally separate wound field (24) and permanent magnet (38) rotor portions. A rotor excitation circuit applies a forward polarity to the wound field rotor portion (24) to increase output in a boosting mode at low RPMs and a reverse polarity to decrease output at high RPMs in a bucking mode to maintain a constant voltage output. Alternative embodiments combine a magnetic flux concentrating design for efficient low speed operation with integral strength for high speed capability. Dual voltage output is provided using only one stator winding. A three state voltage regulator allows voltage regulation without inducing reverse currents onto the power bus in the lightly loaded or no battery conditions. The regulator has automatic interlocking to automatically turn on and off without risk.

Method and apparatus for dynamically charging a battery

Abstract: A charger determines the voltage baseline (204) of a battery and establishes a voltage range based on the voltage baseline of the battery. Once the rapid charge rate has terminated (212) and the trickle charge rate commenced (214), the charger monitors the voltage of the batery (218) in order to make sure the battery is not being depleted. If the battery voltage is above the established range (220), the trickle charge rate is decreased (222), and if the battery voltage is below the voltage range (224), the trickle charge rate is increased (226).

Power conversion equipment monitor/controller method and apparatus

Abstract: Power inverter equipment monitor/controller method and apparatus are described. The invented apparatus provides for the semi-automatic state steering and monitoring of an inverter/charger and alternator system. A flat panel user interface includes an array of switches, displays and indicators for establishing modes of operation of the system, for initializing operating parameters of the system and a connected battery, for establishing rates for the system's operation, permit the user to monitor the system's operating mode and charging data (including charging efficiency factor or CEF) while it is operating to charge the battery and to supply AC power to connected appliances. By the one of the preferred methods of the invention, ramping-up the alternator's output of current, sustaining the output until the voltage of the battery is acceptable, adjusting the output while maintaining the battery voltage at an acceptable level, reducing output until float level voltage is obtained and further adjusting output to maintain float level voltage to preserve the battery charge. By the other of the preferred methods, certain charge data related to the charging of the battery--including a present CEF, maximum amp-hour charge level capacity of the battery (AH CL capacity), and the present status of amp-hour charge level--are given and stored in memory, the battery is discharged, the lowest-recorded (LR) AH CL is recorded with recharge begins, completing the recharge and storing amount of amp-hours used to recharge, determining an intermediate CEF by dividing AH used-to-recharge battery by difference between the AH CL capacity and LR AH CL, averaging the present CEF with the intermediate CEF to produce a result which is stored in memory as the present CEF, and resetting present status to the AH CL capacity.

Ink jet head drive apparatus and drive method, and a printer using these

Abstract: An inkjet printer provided with an ink jet print head having a nozzle, an ink channel that is connected to the nozzle, and an electrostatic actuator that is composed of a diaphragm that is provided in a part of the ink channel and an electrode placed outside of the ink channel opposite to the diaphragm. The diaphragm is distorted by means of an electrostatic force generated by applying a first voltage to the electrostatic actuator. A second voltage, different than the first voltage, is applied to the actuator to relax the diaphragm and to discharge ejecting ink droplets from the nozzle.

A model relating wearout to breakdown in thin oxides

Abstract: A model has been developed relating wearout to breakdown in thin oxides. Wearout has been described in terms of trap generation inside of the oxide during high voltage stressing prior to breakdown. Breakdown occurred locally when the local density of traps exceeded a critical value and the product of the electric field and the higher leakage currents through the traps exceeded a critical energy density. The measurement techniques needed for determining the density of high-voltage stress generated traps have been described along with the method for coupling the wearout measurements to breakdown distributions. The average trap density immediately prior to breakdown was measured to be of the order of low-10/sup 19//cm/sup 3/ in 10 nm thick oxides fabricated on p-type substrates stressed with negative gate voltages. The model has been used to describe several effects observed during measurements of time-dependent-dielectric-breakdown distributions. The area dependence of breakdown distributions, the differences in the breakdown distributions during constant current and constant voltage stressing, and the multi-modal distributions often observed were simulated using the model. The model contained the provision for incorporation of weak spots in the oxide. >

Dynamic random access memory device with low-power consumption column selector

Abstract: A column selector (34) of a dynamic random access memory device is implemented by a plurality of switching circuits (341-34m) for transferring a potential difference from a sense amplifier (SA1-SAm) to a shared data line pair (DL1/DL2), and one of the switching circuits selectively discharge the data lines (DL1/DL2) of the pair to a ground voltage line (GND) for transferring the potential difference to the shared data line pair, wherein a potential control circuit (37) is coupled between the switching circuits and the ground voltage line for decreasing the current (I) flowing from the data line to the ground voltage line after production of an output data signal (Dout), thereby decreasing the current consumption.

High frequency current conveyor precision full-wave rectifier

Abstract: The design of a precision full-wave rectifier using current conveyors is reported. The design uses a voltage reference circuit to clad the voltage excursions at the output of the rectifier during the zero crossings, which ensures that the usual large signal distortion associated with classical precision rectifiers is avoided. Measured rectifier performance using a 100 MHz current conveyor demonstrates good rectifier integrity at an operating frequency of 30 MHz.

Battery recharging system with state of charge detection that initially detects whether a battery to be charged is already at or near full charge to prevent overcharging

Abstract: A state of charge test is first performed on the battery by applying a current pulse and then observing the voltage decay characteristics which result. Batteries which are initially nearly fully charged exhibit a larger voltage decay than batteries which are not as fully charged. The result of this initial state of charge test is used to determine how to best terminate battery charging. In this way battery overcharging is prevented regardless of the initial state of charge of the battery.