Showing papers on "Sine wave published in 2005"

Synchronous motor drive unit and a driving method thereof

Abstract: A rotary sensor that outputs two analog signals, such as one sine wave and one cosine wave and has multiple periods within one period of the electrical angle of a motor is employed. The motor is energized at each position for a specified length of time upon its startup by using multiple electrical angles corresponding to the multiple candidate absolute angles obtained from the rotary sensor signal as the initial position of the motor, and the electrical angle at which the motor acceleration becomes maximum is determined as the absolute angle. While the motor drive is in operation, on the other hand, the phase difference Δθ between the phase of the motor at the counter electromotive voltage and the control phase is directly computed from the parameters of the motor, sensed current, voltage command and angle speed so as to correct the shifted position.

Hybrid Finite-Volume Finite-Difference Scheme for the Solution of Boussinesq Equations.

Abstract: A hybrid scheme composed of finite-volume and finite-difference methods is introduced for the solution of the Boussinesq equations. While the finite-volume method with a Riemann solver is applied to the conservative part of the equations, the higher-order Boussinesq terms are discretized using the finite-difference scheme. Fourth-order accuracy in space for the finite-volume solution is achieved using the MUSCL-TVD scheme. Within this, four limiters have been tested, of which van-Leer limiter is found to be the most suitable. The Adams-Basforth third-order predictor and Adams-Moulton fourth-order corrector methods are used to obtain fourth-order accuracy in time. A recently introduced surface gradient technique is employed for the treatment of the bottom slope. A new model HYWAVE, based on this hybrid solution, has been applied to a number of wave propagation examples, most of which are taken from previous studies. Examples include sinusoidal waves and bi-chromatic wave propagation in deep water, sinusoidal wave propagation in shallow water and sinusoidal wave propagation from deep to shallow water demonstrating the linear shoaling properties of the model. Finally, sinusoidal wave propagation over a bar is simulated. The results are in good agreement with the theoretical expectations and published experimental results. Copyright © 2005 John Wiley & Sons, Ltd.

Motor drive apparatus, electric actuator and electric power steering apparatus

Abstract: The disclosure concerns a a motor drive apparatus, an electric actuator and an electric power steering apparatus capable of continuous torque control up to the high drive speed and high torque area, in order to enable quick acceleration and deceleration. A controller comprises a voltage saturation detecting apparatus for detecting the voltage saturation of the output voltage of an inverter circuit, based on the battery voltage, and a waveform controller that converts the drive waveform of the inverter circuit into the waveform created by superimposing harmonics of high odd-numbered order on a sinusoidal wave as a fundamental wave of the modulated wave modulated by a PWN carrier wave; and continuously changes the ratio of superimposing the high-order harmonics in response to the voltage saturation detected by a voltage saturation detecting means. This arrangement allows the controller to continuously change the drive waveform of the inverter circuit.

Trigonometric wave generation circuit using series expansion

Abstract: A DTMF signal generating circuit is provided with a frequency designating unit which designates frequencies to form a DTMF signal, a sinusoidal wave computing unit which computes sinusoidal waves by referring to frequencies designated by the frequency designating unit, and a sinusoidal wave synthesizing unit which synthesizes two sinusoidal waves computed by the sinusoidal wave computing unit. The sinusoidal wave computing unit is provided with operators such as an adder-subtracter and a multiplier and generates a sinusoidal wave by determining terms of a Taylor expansion of a sinusoidal function by arithmetic operation.

Active vibratory noise control apparatus

Abstract: A cosine wave over one period is stored as waveform data in a memory, and address shift values based on a phase lag in transfer characteristics from a speaker to a microphone are stored in a memory An address shift value is read from the memory by referring to the frequency, and waveform data are read from the memory at addresses that are produced by shifting the addresses from which the reference cosine wave signal and the reference sine wave signal are read, by the address shift value The read waveform data are used as a first reference signal and a second reference signal, which are applied to adaptive notch filters, to suppress vibratory noise

Modulation method for a multiple drive system based on a two-stage direct power conversion topology with reduced input current ripple

Abstract: A new two-stage multi-drive direct power conversion (DPC) topology suited for multi-drive application is proposed, having an input port for a three-phase power supply and several output ports to connect three-phase loads, which are independently controlled and allow for sine wave in-sine wave out operation. This is a cost effective topology compared to a standard matrix converter because the multiple three-phase loads share the cost of the controlled rectification stage. A new method to reduce the high frequency ripple from the input current is also proposed based on interleaving the switching patterns of the inversion stages, which have to form two groups, allowing for size reduction of the input current filter. This is validated by experiments on a realistic laboratory prototype, while its limitations are determined by simulations.

Simulation of wave-energy converter with octagonal linear generator

Abstract: To extract electrical energy from sea waves in a commercially and technologically acceptable manner, a number of issues have to be solved. Electricity generation by means of direct conversion of the oscillating gravitational potential energy of a floating buoy can be anticipated, provided a proper design of a generator could be made. This paper deals with the simulation of a novel design for a linear generator aimed for the extraction of energy from ocean waves. The ocean waves are modeled by 4-m-height sinusoidal waves with a characteristic period of 7 s. A wide range of the geometrical sizes, permanent magnets, stator winding, and spring forces acting on the buoy are possible. This paper presents simulations of octagonal three-phase linear generators in the 100-kW power range. The beneficial effects of a stator of octagonal shape are briefly investigated, but not studied in depth. The main emphases in the present study have been to decrease power fluctuations and suppress voltage harmonics. In conventional rotating machines, well-known measures are to use a fractional number of slots per pole and phase, and an additional method is to make the pole edges smoother. These methods are here simulated for the first time on a linear machine aimed for ocean wave-energy conversion and a substantial reduction in power fluctuations and voltage harmonics are predicted.

Mixed-signal reflectometer for location of faults on aging wiring

Abstract: Location of faults on aging cables is of great interest to maintainers of aircraft, cars, power distribution systems, communication systems, etc. One class of methods for locating faults is frequency domain reflectometry (FDR), using sine waves as the forcing function. A new frequency domain method called mixed-signal reflectometry (MSR) is described in this paper and compared to data from phase detection FDR (PDFDR) methods. The MSR is less expensive and smaller than the PDFDR and has very similar performance. A prototype system using the 100-200-MHz bandwidth with 256 40-kHz steps is shown to have a resolution of about 10 cm, very similar to a PDFDR in the same frequency band.

System and method for narrow bandwidth amplitude modulation

Abstract: A method and system for narrow band amplitude modulation in which audio is sampled periodically and held constant except during brief periods which are close to zero crossings of the carrier signal comprising an RF sine wave. The result is a modulated signal with sidebands of reduced amplitude. Without sidebands, the modulated RF sine wave may thus be very narrow banded, allowing many more stations to fit within the same band.

Self-oscillating rubidium magnetometer using nonlinear magneto-optical rotation

Abstract: The detection of nonlinear magneto-optical rotation (NMOR) of polarized light through alkali atomic vapor is a highly sensitive technique for measuring magnetic fields. We demonstrate that when using frequency modulated light to excite the NMOR resonance, it is possible to cause the system to self-oscillate. The NMOR signal is not a simple replica of the sine wave modulation of the light, but rather contains many higher harmonics of the modulation frequency, and we implement two ways of processing the signal to recover the fundamental modulation frequency in the feedback loop and induce self-oscillation. Self-oscillation simplifies and reduces the power consumption of the electronics required to operate a magnetometer, making the NMOR technique attractive for commercialized magnetic sensors.

An AMR sensor-based measurement system for magnetoelectrical resistivity tomography

Abstract: A magnetoelectrical resistivity measurement system is proposed, which combines measurement of the electric potential and the magnetic field due to a current injection into a sample. Measurement of the electric potential, as well as the injected current, is similar to traditional electrical resistivity tomography (ERT) data acquisition. For the magnetic field measurements, 24 sensor modules have been developed using three component anisotropic magnetoresistive (AMR) sensors, mounted on a vertically moving scanning torus. The system is designed to operate in a typical laboratory magnetic noise environment without extensive shielding. To compensate for the effects of the Earth's magnetic field, the AMR sensors are operated with a field feedback circuit. Optimal noise reduction is provided by the use of a lock-in frequency of 25 Hz, with sine wave modulation and measurement cycles of 10 s. The resolution of the system is better then 50 pT and the aimed accuracy is 0.1%. The system provides a data set of magnetic fields complimentary to traditional ERT to determine the internal conductivity distribution of cylindrical samples with the dimension of 0.1-m radius and 0.5-m height.

Ferrite losses of cores with square wave voltage and DC bias

Abstract: Ferrite material properties may vary depending on the grade and manufacturer. Moreover, there are differences between batches and also the production process may change in time. The same material grade may have improved or reduced performance depending on the year of production. In loss critical applications it is good to be able to test the losses on real cores. The usual voltage waveforms in power applications are closer to square wave than to sine wave. The DC bias can have a significant influence on the ferrite losses, so it is good to check this sensitivity. Losses were measured at frequencies of 20 kHz, 100 kHz and 500 kHz on 3F3 material

Communication apparatus and communication method using digital wavelet multi carrier transmission system

Abstract: In case of disposing a pilot symbol in data transmission which depends on a DWMC transmission system, in a plurality of transmission symbols on a time axis, a pilot symbol, which becomes a signal of a sine wave, is configured, by giving contiguous identical data in a plurality of predetermined symbols. By transmitting a transmission signal with the use of this pilot signal, between a transmitting device and a receiving device, it is possible to carry out channel equalization by complex information which is obtained from a pilot symbol.

Ultralow noise mode-locked laser and RF sinewave source

Abstract: Systems, devices and methods of generating both a precision electrical timing signal as well as a precision optical timing signal. A novel, modified opto-electronic loop oscillator is used to drive a harmonic mode-locked laser. A novel opto-electronic loop has a larger “Q” factor by increasing the electrical loop oscillating frequency ω 0 by using a beat note created by the selection of two optical longitudinal modes from the mode-locked laser. The beat note is detected and divided down to drive a modulator that mode-locks the laser. The frequency division stage also reduces the noise.

Band Limit and Appropriate Sampling in Microscopy

Abstract: Publisher Summary Data are usually obtained at equidistant coordinates in object space in microscope images obtained with the help of electronic devices or in a scanning microscope system. The distance between these measurement positions is usually denoted as the “sampling distance.” The values of the image function are recorded at the equidistant sampling coordinates. A periodic fluorescence distribution with a count of maxima per μm above this limit frequency will appear as a uniform constant in the image. Since the images can be decomposed into the sine waves, it is useful to consider how an individual sine wave is sampled by the equidistant measurements. To guarantee a unique interpretation of a given measurement, all that needs to be done is to insure all aliasing frequencies lie beyond the a priori known transmittable frequency limit. Selection of the appropriate sampling distances is crucial for almost all optical systems with computerized image acquisition. When the computerized deconvolution is applied to data, it is often useful to over sample data during data acquisition.

Determination of Single-Cell Oxygen Consumption with Impedance Feedback for Control of Sample--Probe Separation

Abstract: The ability to measure chemical gradients surrounding single cells provides novel insights into several areas of cell dynamicsparticularly metabolism. Detection of metabolic oxygen consumption can be achieved from a single mammalian cell using a modulated amperometric sensor in a self-referencing mode. To date, however, apart from visual cues, we do not have a reliable and cell-compatible method for determining and stabilizing the position of such probes. In this paper, we report on having successfully measured the increase in the uncompensated resistance of an electrochemical cell upon approach to single, living, biological cells, while simultaneously measuring the metabolic oxygen consumption. This was accomplished by applying an ac and a dc excitation signal to the electrode. The applied ac waveform was a 100-kHz sine wave with an amplitude of 10 mV rms, while the dc voltage applied was −600 mV. The two signals were shown not to interfere with one another. Furthermore, it is shown that the sample−probe...

System and method for determining harmonic contributions from non-linear loads

Abstract: Neural networks have been known to be good function approximators. They are particularly effective in dealing with non-linear relationships between parameters. This feature is exploited in this paper to propose a new method for the problem of measuring harmonic current injected into a power system network by a non-linear load without disconnecting the load from the network. This work is particularly useful in determining whether the utility or the customer side has a higher contribution to harmonic pollution in a network. Hence this method would be helpful in settling utility-customer disputes over who is responsible for harmonic distortions. The main advantage of this method is that only waveforms of voltages and currents have to be measured. A neural network structure with memory is used to identify or learn the non-linear load admittance of a load. Once it has learned the admittance, the neural network predicts the true harmonic current of the load when supplied with a clean sine wave. This method is applicable for both single and three phase loads. This could be fabricated into a commercial instrument that could be installed in substations of large customer loads, or used as a hand-held clip on instrument.

A 5.5 V SOPA line driver in a standard 1.2 V 0.13 /spl mu/m CMOS technology

Abstract: In this work a high voltage line driver, using a self-oscillating power amplifier (SOPA) in a digital 1.2 V 0.13 /spl mu/m CMOS technology is presented. A self biasing cascode topology allows the line driver to operate at 4.5 times the nominal supply voltage. Oxide breakdown and hot carrier degradation is minimized since the driver operates within the voltage limits imposed by the design rules of a mainstream CMOS technology. The realized prototype delivers a 35 MHz PWM square wave with a 4.6 V swing in a 7.1 /spl Omega/ load with an efficiency of 62%. The chip achieves a spurious free dynamic range (SFDR) of 52 dB while driving a 1 MHz sine wave. A missing tone power ratio (MTPR) of 50 dB has been measured for a DMT signal up to 1.1 MHz with a crest factor of 14 dB.

Experimental Optimization of Extreme Wave Sequences for the Deterministic Analysis of Wave/Structure Interaction

Abstract: For the deterministic analysis of wave/structure interaction in the sense of cause-reaction chains, and for analyzing structure responses due to special wave sequences (e.g. three sisters phenomenon or other rogue wave groups) methods for the precise generation of tailored wave sequences are required. Applying conventional wave generation methods, the creation of wave trains satisfying given local wave parameters and the generation of wave groups with predefined characteristics is often difficult or impossible, if sufficient accuracy is required. In this paper we present an optimization approach for the experimental generation of wave sequences with defined characteristics. The method is applied to generate scenarios with a single high wave superimposed to irregular seas. The optimization process is carried out in a small wave tank. The resulting control signal is then transferred to a large wave tank considering the electrical, hydraulic and hydrodynamical RAOs of the respective wave generator in order to investigate wave/structure interaction at a large scale.Copyright © 2005 by ASME

Tracking and disturbance rejection for passive nonlinear systems

Abstract: In this paper, we apply internal model principle for plants that are passive nonlinear systems, to solve tracking of constant reference signal and disturbance rejection of a finite superposition of sine waves of arbitrary known frequencies. A desirable passivity property around an equilibrium (x 0 ,u 0 ) which generates y 0 is used to design the controller. The proposed controller is an LTI system, which assures that the state trajectories of the closed loop system is bounded and the error signal converges to zero.

Ultrasonic brain infarction treating device

Abstract: Ultrasonic brain infarction treating device in which formation of a standing wave due to interference of between an ultrasonic beam projected into the skull and a reflected beam is avoided and side effects, e.g. destruction of brain cells, occurrence of intracerebral hemorrhage, destruction of nerve tissue, and the like are prevented. An ultrasonic probe cap (20A) is constituted by arranging a plurality of multilayer small transducers (21) composed of a PVDF film, PZT ceramic, and the like on the inner surface of the cap in a mosaic or another pattern. As a high frequency for driving the transducers a continuous sine wave, a burst wave or a pulse wave is used. In order to prevent generation of a standing wave in the skull, the frequency modulation rate is set at 1 ms or less and the repetition period is set at 1 ms or less for the continuous sine wave, and one excitation period is set at 1 ms or less and the repetition period is set at 1 ms or less for the burst wave and the pulse wave. The plurality of multilayer small transducers (21) are driven selectively depending on the location of a thrombus. A cooling jacket is disposed between the cap and the head in order to suppress temperature rise in the skull and to cool the transducer.

DSP Based Portable Impedance Measurement Instrument Using Sine-Fitting Algorithms

Abstract: The development and implementation of a digital signal processor (DSP) based portable impedance measurement instrument is described in this paper. The circuit sinewave stimulus is generated by the device using a direct digital synthesizer at the desired measurement frequency. The sine is applied to a reference impedance in series with the unknown impedance. Two analog to digital converters (ADCs) acquire multiple samples of the two sine voltages which are transmitted to the DSP. Sine-fitting algorithms determine the sine amplitudes, phases, DC components and frequency. From these values and the reference impedance values, the impedance amplitude and phase are determined. Included in the device, amplifiers extend the ADCs input range while a digital potentiometer enables the adjustment of the reference impedance to improve accuracy

A novel technique for control of cascaded multilevel inverter for photovoltaic power supplies

Abstract: Multilevel voltage source inverters offer several advantages compared to their conventional counterparts By synthesizing the AC output terminal voltage from several levels of voltages, staircase wave forms can produced, which approach the sinusoidal wave form with low harmonic distortion, thus reducing filter requirements The need of several sources on the DC side of the converter makes multilevel technology attractive for photovoltaic applications The basic modulation techniques enable harmonic elimination by predetermination of the switching angles This is determined according to a previously calculated and stored pulse width modulated waveform It has the advantage of operating at fundamental frequency switching However, this technique is seriously limited as the number of levels increases because of the increased complexity and the reduced accuracy of the non-linear solutions This paper proposes a novel multilevel PWM technique (phase-shifted sinusoidal PWM) to over come all these limitations while maintaining switching at fundamental frequency, found better THD Simulation results are presented in the paper

Efficient electromechanical (E/M) impedance measuring method for active sensor structural health monitoring

Abstract: Electro-mechanical impedance method is emerging as an important and powerful technique for structural health monitoring. The E/M impedance method utilizes as its main apparatus an impedance analyzer that reads the in-situ E/M impedance of the piezoelectric wafer active sensors (PWAS) attached to the monitored structure. Present-day impedance analyzer equipments (e.g. HP4194) are bulky, heavy and expensive laboratory equipment that cannot be carried into the field for on-site structural health monitoring. To address this issue, several investigators have explored means of miniaturizing the impedance analyzer making the impedance analyzer more compact and field-portable. In this paper we present an improved algorithm for efficient measurement of the E/M impedance using PWAS transducers. Instead of using a sine wave as the excitation signal to the PWAS and slowly changing its frequency, our method utilizes a chirp signal which is abundant in frequency components. By applying Fast Fourier Transform (FFT) to both the input and response signals, the impedance spectrum of the PWAS is acquired. The algorithm was implemented and tested in a real-time system, which consists of excitation signal generation module, voltage and current measurement module and digital signal acquisition module. The size and the implementation of the overall system using either a laptop or a digital signal processor (DSP) are also discussed. Finally, practical results are presented and comparatively examined.

An overview of the modern light dimmer: design, operation, and application

Abstract: The light dimmer is a specialized circuit that utilizes switching techniques to control the brightness of a light fixture. Thyristors (unidirectional semiconductor device) and triacs (bidirectional semiconductor device) are the basic power electronic devices used to control the switching. Once the current crosses the zero-crossing of AC power, the brightness is determined. The sine wave is cut in accordance to the zero-crossing to determine the output power. The light dimmer is an efficient and practical application of power electronic devices in an industrial or consumer product.

Motor driving device

Abstract: PROBLEM TO BE SOLVED: To generate a sinusoidal wave for driving a brushless motor in a sensorless manner without requiring any calculation with a CPU, in an inverter device for PWM driving. SOLUTION: The motor driving device comprises a multi-phase inverter where the arms composed of two switching elements connected in series are provided to a DC power source 1 in parallel by corresponding number of pairs of output phases; a switching signal generating means 13 for driving the inverter; a sampling means 6 for outputting a sampling signal PA, synchronized with such timing as all switching elements connected to one side of the DC power source 1 are in on-state; a phase current change rate detecting means 7 which takes in a phase voltage at the output terminal of the multi-phase inverter, synchronized with the sampling signal PA to detect a phase voltage change rate signal, and outputs it as phase current change rate signals (PBU, PBV, PBW) at zero-crossing of the phase voltage; and a phase control means 14 which generates a phase control signal according to the phase current change rate signal and supplies it to the switching signal generating means 13. COPYRIGHT: (C)2005,JPO&NCIPI

Drive circuit for piezoelectric pump and cooling system that uses this drive circuit

Abstract: A piezoelectric element of the piezoelectric pump is driven by the output signal of an amplifier that takes as input a signal that is generated by a sine wave oscillator of the same frequency that drives the piezoelectric element. The amplifier is driven by a high voltage obtained by conversion from a low-voltage power supply by a voltage-boosting converter, whereby the piezoelectric element is driven by a low-frequency sine wave of high voltage. The frequency of the sine wave oscillation is further adjusted by a signal from a first control circuit at the time of activation. In addition, the amplitude of the sine wave oscillation is adjusted by the output signal of a second control circuit that takes as input a signal from temperature sensor for sensing the temperature of the heat-generating body.

Distance detecting apparatus and body detecting apparatus

Abstract: PROBLEM TO BE SOLVED: To provide a distance detecting apparatus capable of improving the SN ratio of received signals. SOLUTION: An angular frequency (ω 1 ) of sinusoidal wave signals generated by a sinusoidal wave generator 4 is brought into synchronism with an angular frequency (ω) of burst pulse signals, and signals received by a transmitter/receiver microphone 5 are orthogonally demodulated by using sinusoidal wave signals of this synchronized angular frequency. A microcomputer 1 adds up the vectors of the demodulated signals for only a period of time equal to a section of transmitting the transmission waves from the transmitter/receiver microphone 5. A distance to a body is detected by using these received signals of which the vectors are added up. COPYRIGHT: (C)2005,JPO&NCIPI

Wave propagation in granular materials

Abstract: Wave propagation is a fundamental property of all physical systems. The wave speed is directly related to the compressibility of the system and determines the rate at which local disturbances are propagated into the bulk of the material. The wave propagation characteristics of conventional forms of matter are well understood and well documented. In contrast, waves in granular materials are more complex due to the heterogeneous nature of these systems. The key element of the mechanics of a granular system is the force chain. It is along these preferentially stressed chains of particles that waves are transmitted. These nonlinear chains are heavily dependent on the geometry of the bed and are prone to rearrangement even by the slightest of forces. Results from both experiments and simulations on wave propagation in granular materials are presented in the current study. The experiments measure the pressures at two points within the granular bed that result from the motion of a piston at one end of the bed. The simulations are a two-dimensional version of the experiments and use a discrete, soft-particle method to detect the wave at both the output of the simulated bed and at any point within it. In addition to examining wave propagation in a granular bed at rest, simulations and experiments are also performed for a granular bed undergoing agitation perpendicular to the direction of the wave input. Imposed agitation increases the granular temperature of the bed and allows for the exploration of the effect of granular state changes on the wave propagation characteristics. Such information may provide a means to diagnose the state of a flowing granular material. Measurements of the wave speed and attenuation in the bed reveal the unique properties of waves in granular systems that result from the nonlinearity of the bed and the heterogeneity of the force chains. Sinusoidal waves demonstrate the nondispersive nature of a granular bed and show the transient effects of force chain rearrangement. Pulsed waves display a semi-permanent shape qualitatively similar to predictions from nonlinear wave theory. In an agitated granular bed, measurements of the wave characteristics were found to be possible even in the presence of significant agitation. The prevailing confining pressure, which changes throughout the agitation cycle, was determined to be the system parameter that correlates best with changes to the wave speed.

Sine-Wave Signal Characterization Using Square-Wave and ΣΔ-Modulation: Application to Mixed-Signal BIST

Abstract: This paper presents a method for extracting, in the digital domain, the main characteristic parameters of an analog sine-wave signal. It is based on a double-modulation, square-wave and sigma-delta, together with a simple Digital Processing Algorithm. It leads to an efficient and robust approach very suitable for BIST applications. In this line, some considerations for on-chip implementation are addressed together with simulation results that validate the feasibility of the proposed approach.