Source Phase Angle Research Articles

Sensorless Node Architecture for Events detection in Self-Powered Nanosensor Networks

Due to size, computational and power limitations an integrated nanosensor device needs to be redesigned with a limited number of components. A sensorless event detection node can overcome these limitations where such node can be powered using energy harvested from various events. The harvested energy could also be a significant factor for events detection without using any sensors. This study presents a detailed description of a sensorless event detection node which consists of two components — an energy harvester and a pulse generator. We discuss the state of the art configurations for these two components. However, due to the low complexity of the nanoscale device, the pulse generator should be kept simple. We, therefore, theoretically investigate different approaches for the pulse generator to generate Surface Plasmon Polaritons (SPPs) which reasonably resemble femtoseconds long pulses in graphene. Based on our analysis, we find that SPPs can be excited using a near-field excitation method for the THz band which is simple and can produce Electromagnetic (EM) radiation with a wide range of high wavenumber. Hence, the coupling condition can be easily satisfied and consequently, the SPP wave can be excited. However, such method excites SPPs locally, which requires improvement in practice. Thus we numerically investigate how operating frequency, the doping amount of graphene and the properties of the evanescent source affect the plasmon resonance of SPPs. We also studied different evanescent sources such as electric dipole, and hexapole, and find that the former provides better SPP resonance. We also observe that through fine-tuning of the chemical potential, frequency and source phase angle, higher amplitude SPPs can be excited on graphene surface in the THz band. The proposed model can be a good candidate for a low-complexity realization of a THz pulse generator in self-powered sensorless events detection node.

A Step Forward in Application of Dynamic Harmonic Domain: Phase Shifting Property of Harmonics

In this paper, a novel analytical approach is put forward which leads to phase-shifting property of harmonics in a periodic system. Based on the illustrations, it is shown that if all of the input sources of the periodic system are shifted by α, the entire outputs will be shifted by α as well in both transient and steady states. There is no limitation for such a system as it can be either single or three phase, linear or nonlinear, or supplied by periodic balanced or unbalanced sinusoidal/nonsinusoidal sources. According to this concept, the source angle affects only the phase angle of harmonics linearly but not their magnitude. However, related time-domain response may be greatly affected. These characteristics of the harmonics are observed using the dynamic harmonic domain analysis which calculates exact variations of harmonics. To such aim, a phase-shifting matrix is defined which provides exact phase-shift calculation considering each harmonic order. The introduced concept significantly reduces the required simulation time and represents the effects of the source phase angle on the harmonic content and time-domain response without performing extra simulations. Finally, the novel concept is successfully applied to two test cases, followed by analysis and discussion.

Gyrator-Based Analysis of Resonant Circuits in Inductive Power Transfer Systems

In this paper, first, it is found that not only the magnetically coupled inductors but also all inductive power transfer systems (IPTSs) inherently have the nature of a gyrator. Widely known characteristics of IPTSs such as impedance inversion and source-type conversion are proved to be the nature of the gyrator. A graphical approach that utilizes the gyrator is proposed for the modeling of IPTSs in general. The proposed graphical technique enables manipulations on the circuit diagram instead of on the circuit equations, which are difficult to handle when the system order is higher than 4. Hence, the equivalent model can be obtained almost by inspection conveniently, giving fruitful physical insights that are limitedly achieved with the equation manipulations. Steady-state analyses at any frequency are possible, and equivalent series resistances can also be included in the proposed model. Five selected electrical characteristics, i.e., source-to-load gain, load-independent output voltage/current characteristics, power factor at the source, sign of the source phase angle, and allowances of open/short loads are evaluated for three widely used IPTS topologies. Also, this technique is extended to the mistuned case for verifying the general use of the approach. An experimental prototype of the voltage-source-type inductor-capacitor-inductor secondary-parallel (V-LCL-P) topology was built to demonstrate the proposed approach for both perfectly tuned and mistuned situations at 85 W and 100 kHz.

Phasor-based assessment for harmonic sources in distribution networks

Phasor-based interdependencies of multiple harmonic sources, especially Distributed Energy Resources, on distribution networks are analyzed in this paper. A new index, Phasor Harmonic Index (IPH), is proposed by the authors. IPH considers both harmonic source magnitude and phase angle for different harmonic orders. Other commonly used harmonic indices are based solely on magnitude of waveforms. A very detailed model of a distribution network is used in the harmonic assessment. With the help of the detailed distribution network model, the phase couplings and the phase balancing impacts on harmonic propagation between three phases are investigated. Moreover, effects of harmonic source phase angle deviations are analyzed at both the customer side and the substation side. This paper investigates the importance of phase angles in harmonic assessment and how distribution network characteristics can be analyzed appropriately with phasor-based harmonic studies. In addition to device level harmonics, system level harmonic propagation need to be considered.

An equivalent source model for the sound intensity in the vicinity of a high-performance military aircraft

The sound field of the F-22A Raptor has been measured extensively using arrays of microphones including an intensity probe to the sideline and rear of the aircraft. Recently, an equivalent source model (ESM) has been proposed that incorporates two arrays of monopole sources placed along the jet axis and their image sources to account for the hard ground. The monopole amplitudes in each case are described by a Rayleigh distribution, and one array includes a phase angle between the monopoles to produce correlated noise steered in a specific direction. The model closely replicates the measured SPL at the majority of measurement locations. However, agreement with energy-based quantities such as the vector acoustic intensity may not follow from agreement with the pressure measurements alone. Hence, in this work, the ESM’s ability to produce intensity estimates that match the measured F-22A intensity is evaluated. A new method of estimating acoustic intensity, known as the phase and amplitude gradient estimation (PAGE) method, is applied to the measured F-22A data. The PAGE method accurately estimates intensity in a larger bandwidth than the traditional finite difference method, expanding this discussion of the ESM's accuracy. In addition, sensitivity of ESM parameter selection, e.g., correlated source phase angle and peak amplitude location, on changes in the predicted intensity is examined. [Work sponsored by ONR.]

Control of Series Active Power Filters Compensating for Source Voltage Unbalance and Current Harmonics

In this paper, a novel control scheme compensating for source voltage unbalance and current harmonics in series-type active power filter systems combined with shunt passive filters is proposed, which focuses on reducing the delay time effect required to generate the reference voltage. Using digital all-pass filters, the positive voltage sequence component out of the unbalanced source voltage is derived. The all-pass filter can give a desired phase shift and no magnitude reduction, unlike conventional low-or high-pass filters. Based on this positive-sequence component, the source phase angle and the reference voltage for compensation are derived. This method is easier to implement and to tune controller gains. In order to reduce the delay time effect in the voltage control loop, the reference voltage is predicted a sampling period ahead. The validity of the proposed control scheme has been verified by experimental results.

Single-Phase High Power Factor PWM Converter without Source Phase Angle and Voltage Detectors.

In this paper, the authors propose a current control system of a single-phase PWM AC/DC converter which eliminates detectors of the source phase angle and voltage. The sinusoidal input current and unity effective power factor are realized based on the estimated source voltage in the controller. The feature of the proposed estimation algorithm is that the estimations of the phase angle and crest value of the source voltage are independent each to each. The estimations are performed based on the current error between the actual and model currents. The orthogonal and in-phase components of the current error with respect to the estimated phase angle are proportional to the phase angle and crest value errors, respectively. Therefore, the estimations of them can be realized by feeding back the corresponding components of the current error.The effectiveness of the proposed current control system was confirmed by experiments. The stable estimation and control were achieved.