Phase Shift Angle Research Articles

Influence of design and annealing parameters on measurements of AC properties of NiFe-SiO2 multilayer structures

In this article, due to the exceptionally interesting electrical and magnetic properties of nanocomposites, which include ferromagnetic materials in a dielectric matrix, multilayer NiFe-SiO2 nanocomposites were obtained. The entire sequence of technological processes using magnetron sputtering equipment in the presence of argon was presented, the aim of which was to create structures with different numbers and thicknesses of layers, as well as in two measurement configurations. Measurements of AC electrical properties were carried out in a variable temperature range, i.e. from room temperature to 373 K, using the 4-point method. The obtained measurement results were compared in terms of design parameters, such as thickness and number of layers, as well as technological parameters, such as heating duration. Structural analysis was performed using scanning electron microscopy (SEM) to investigate the effect of oxidation on the multilayer structures and to confirm the granular structure of the nanocomposite. Additionally, the chemical composition of the obtained multilayers was examined using Energy-dispersive X-ray spectroscopy (EDX). Resistive parameters were tested in the range of magnetic field induction from 0 T to 0.3 T. Based on the conductivity relationships, it was proven that a hopping mechanism of current conduction occurs in the tested samples. Using the frequency dependencies of the phase shift angle, it is possible to adjust the equivalent RC electronic circuit, thereby determining the potential application of the tested materials.

Extremely Low Frequency PS-PWM Based Technique for Cascaded H-Bridge Converters With Grid Voltage Compensation Capability

Cascaded H-Bridge Converters (CHB) are good candidates for many industrial applications. Among the modulation techniques that can be applied to CHB converters, the Phase-shifted PWM method (PS-PWM) provides very good harmonic quality being the most popular modulation technique at the expense of presenting high switching losses. On the contrary Block Switching technique as well as Selective Harmonic elimination/mitigation (SHE/SHM) techniques provides lower switching frequency and losses with a lower harmonic quality. Additionally with these techniques the converter operation becomes stiff. In this work a modification of PS-PWM based on an extremely low frequency carrier is proposed with the objective of achieving both low switching losses and an acceptable harmonic quality, simultaneously. The main advantage of the proposed solution is the capability of adjusting the phase-shift angle among the carriers to compensate for harmonic grid voltage disturbance. Several experimental results have been reported to demonstrate the good performance of the proposed modulation technique.

Performance Analysis of a Dual-Inverter-Fed Open-End Winding Induction Machine under Asymmetrical Control: Theoretical Approach and Experimental Validation

Currently, power trains based on an Open-End Winding Induction Machine fed by a Dual Inverter (DI-OEWIM) are attracting a great deal of interest in various modern industrial applications. However, applying symmetrical control to this system (DI-OEWIM), which is symmetrical in nature, will lead to malfunction. Therefore, the objective of this paper is to explore the influence of asymmetric control on the performance of this system. The principle of this study is to create an asymmetrical control by integrating a phase-shift angle in the Space Vector Pulse Width Modulation (SVPWM) strategy. We then evaluate the impact of these angles on various performances, such as the Total Harmonic Distortion (THD), power losses, Common Mode Voltage (CMV), Zero-Sequence Voltage (ZSV), rotation speed and torque ripple of this system. This study was carried out in the Matlab/Simulink environment and was validated experimentally using the dSPACE 1104 board. The results show that the different angles have significant effects on the overall performance of this system.

Phase-Shifting Adaptive LLC Resonant Converter with Reduced Turn-Off Loss in Wide Voltage Application

In this paper, a hybrid control method with adaptive phase-shifting modulation (PSM) and pulse-frequency modulation (PFM) is proposed to optimize the steady-state performance of an LLC resonant converter in wide voltage-gain range application. For the primary-side switches under the hybrid control method, zero-voltage switching (ZVS) performance is maintained over wide voltage-gain range and the turn-off loss is reduced; therefore, the converter reconciles wide voltage-gain range and high efficiency. Mode characteristics under different phase-shifting-angle-θ and switching-frequency-fs combinations is analyzed, and then the soft-switching characteristic is revealed. By introducing time domain analysis, the turn-on current of the primary-side switches is calculated, and thus the ZVS boundary of different θ and fs combinations is inferred. In addition, to acquire the optimum steady-state operation of the converter, the turn-off current is calculated; by making the converter work near to the minimum turn-off current operating point, the turn-off loss can be reduced greatly. With the principles of achieving ZVS performance and minimizing turn-off current, the phase-shifting angle θ of PSM is designed to be adaptive to the reference output voltage, no additional circuits are needed, and the two control degrees (θ and fs) are simplified to one (fs). The simulation and experiment are developed to verify the feasibility and effectiveness of the hybrid control method; the results show that ZVS performance is maintained at wide voltage-gain range and the turn-off current of the hybrid control method is reduced to that of the single PFM, and thus the turn-off loss is reduced. The efficiency comparison validates the fact that the hybrid control method has less power loss than single PSM and single PFM.

Dynamic Modeling Approach in View of Vector Control and Behavior Analysis of a Multi-Three-Phase Star Permanent Magnet Synchronous Motor Drive

In order to fully utilize the control degrees of freedom of a multi-three-phase-star smooth-pole permanent magnet synchronous motor (PMSM), this paper first develops a modeling approach using a new matrix transformation method. The proposed transformation produces decoupled and independent star windings, removing the inductive couplings and preserving the model and torque control’s consistency as the number of phases increases. The model, together with a new vector control scheme, is superior for studying the effect of the winding phase angle shift on motor performance. Based on a numerical simulation, this paper focuses on the quality analysis of phase currents, non-sequential currents, and torque ripple with different phase angles for double- and triple-star PMSM drives. The control of a triple-star PMSM is validated, and the behavior analysis is investigated by OPAL-RT.

An Efficiency Improvement Strategy for Triple-Active-Bridge-Based DC Energy Routers in DC Microgrids

A triple-active bridge (TAB) can be used as a power conversion unit in a three-port DC energy router (DCER) such as a triple-active bridge-based DC energy router (TAB-DCER). The operational loss of a TAB can be seen as a key factor affecting the efficiency of a TAB-DCER. However, the RMS value of the inductor current of the TAB-DCER increases under single-phase shift (SPS) control, and this greatly increases the system operating losses. The use of phase-shifted plus PWM (PS-PWM) control can reduce the RMS value of the inductor current, but its mathematical model is complex, and involves difficult calculations. To address this problem, in the study reported here, we developed an optimal control strategy for the RMS value of the inductor current based on TAB-DCER. First, the working principle of a TAB-DCER under PS-PWM control was analyzed, and a circuit decomposition model was established. Second, the operating modes under PS-PWM control were analyzed, and corresponding expressions of port power and the RMS value of the inductor current were obtained. Third, an optimized mathematical model of the sum of squares of the RMS value of the inductor current of the TAB-DCER was constructed. Finally, a genetic algorithm was used to solve the mathematical model and derive the optimal phase shift angle; this resulted in a lower RMS value of the inductor current in the TAB-DCER and reduced the system operating losses. The simulation and experimental results show that the TAB-DCER used in the present study can reduce operating losses, improve system efficiency, and deliver coordinated power control.

Investigation of the performance of a horizontal-axis dual rotor wind turbine

Recent years have seen a rise in interest in wind energy as a useful alternative to harmful energies like fossil fuels. The dual rotor wind turbine (DRWT) offers more rapid rates of wind energy extraction. The current study intends to compare the performance of the turbine with and without the addition of a second rotor. Additionally, it examines how tip speed ratio and phase shift angle will affect DRWT performance. Realizable k-shear stress transport turbulence models are used to solve the three-dimensional, turbulent, stable, and incompressible flow equations for the performance of dual-rotor wind turbines. Domain-independence tests and an impartial mesh test are run to assess the results and ensure their accuracy. The researcher relies on previous studies while constructing the single rotor wind turbine model. This model uses an S826 airfoil. The front and rear rotors are given streamlined representations using ANSYS, according to the researcher. The independent mesh test indicates that the mesh density has 11.5 million elements. The experiment's results show that the DRWT has a significant effect on the efficiency of wind energy.

Phase Shift Angle Segmentation Modulation for Soft-Switching Medium-Voltage DAB Converter With Series-Connected SiC MOSFETs

Medium voltage (MV) dual active bridge (DAB) converter with series-connected SiC MOSFETs (S-SiC) is a promising solution for high power density isolated DC/DC converter. To improve the voltage sharing and reliability of S-SiC, relatively large snubber capacitors are connected in parallel with S-SiC. But this narrows the zero voltage switching-on (ZVS-on) range of S-SiC, and even reduces the efficiency and reliability of the entire converter. Adding non-optimized internal phase shift angle to the low-voltage (LV) side switching unit will result in excessive circulating power and still lead to low efficiency. In this paper, the phase-shift angle segmentation modulation (PSSM) scheme featuring soft-switching performance is proposed for a MV DAB converter with S-SiC. The proposed modulation scheme is based on a detailed derivation of the ZVS-on range and operation modes. Then, the changes in operation characteristics and the advantages brought by the proposed modulation scheme are analyzed in terms of transmission power, state transition process, switching current and device losses. Moreover, the introduced modes and ZVS-on characteristics are verified on the 4kV/1kV 200kW experimental prototype. As a result, the converter’s loss can be decreased by up to 75% under light load, validating the efficiency advantage of the proposed modulation scheme.

A partial energy current‐sharing method for interleaved LLC converter with phase shift current balance module

AbstractA partial energy current‐sharing method for an interleaved LLC resonant converter with a phase shift current balance module (CBM) is presented in this paper. The current sharing is achieved by controlling the phase shift angle of the bridge in the CBM. The proposed method maintains excellent soft‐switching performance, minimizes power losses, and ensures high overall efficiency as only partial energy is processed. This method simplifies current sharing in the resonant converter by using phase shift control, making it easy to implement and extend to multiple phases. A 500‐kHz two‐phase interleaved LLC prototype was built to validate the effectiveness of this method in achieving current balancing.

Commutation torque ripple suppression method for brushless DC motors with minimum phase shift angle

SummaryCommutation torque ripple occurs when brushless DC (BLDC) motor runs in the high‐speed range, which degrades operation performance. To overcome the problem, this paper presents a commutation torque ripple suppression method based on the minimum phase shift angle (MPSA) of hall signals. In the paper, the effect of the phase shift angle (PSA) of hall signals on phase current is analyzed, and the MPSA is deduced on the basis of the unit duty cycle of the incoming and non‐commutation phase. With the proposed method, two‐phase conduction mode is used in the full speed range, commutation period and non‐commutation period, which avoids switching modulation mode and enhances system reliability. The proposed method is implemented through shifting hall signals by the MPSA, and it is simple and feasible without the requirement to redesign a controller. Moreover, no additional power devices and precise sensors are required, which reduces design cost and volume size. The proposed method is experimentally compared with different methods under steady operation condition, and the results show superior performance on suppressing commutation torque ripple. The loading experiment demonstrates that the proposed method exhibits good dynamic response. The frequency spectrum of the electromagnetic torque is analyzed, and it is verified that the 6nf harmonics are diminished with the proposed method.

An Innovative Embedded Processor-Based Signal Phase Shifter Algorithm

Digital filtration is widely used today in many application fields, and with the increased use of low-cost embedded processors, it can be applied to vast areas. A drawback of digital filtration algorithms is the introduction of phase angle shifts in the filtered signals, thereby creating undesirable characteristics in many application fields. In this work, low-pass filters of finite impulse response and infinite impulse response types are designed with an innovative buffering scheme to delay a digitally low-passed signal by an angle ranging from 0° to 180° for real-time signals. The application of the filtration and buffering scheme on a cost-effective embedded processor with limited signal processing capabilities opens the horizons for its applicability in many signal processing fields. In assessing its practicality, the generated filtered output signal is correlated with the original signal (a low-passed version), revealing correlation values reaching 0.99 in certain instances. The novelty of the proposed approach enables its application to a broad-spectrum area of digital signal filtration.

MEASURING THE SMALL LINEAR DISPLACEMENTS BY THE PHASE METHOD

A measuring device with a differential capacitive measuring transducer (CMT) designed to measure small linear displacements is considered. The CMT has a plane-parallel design of the plates, the natural input value is the change in the gap between the plates. In the measuring circuit (MC), model resistors with the same resistance are connected in series with the sensitive elements of the CMT. The voltage dividers formed by these connections are powered by counter currents of a high-frequency sinusoidal voltage generator. An informative measurement parameter is the phase shift angle between the two output voltages of the MC. These voltages are supplied to the analog inputs of the programmable microcontroller (PMC). The PMC controls the measurement process, measures the specified phase shift angle and determines the measured displacement. Thanks to the used algorithm for processing the measurement results, a ratiometric output signal is obtained to determine the measured displacement. This ensures high metrological characteristics of the meter. The theory of the meter's functioning, the features of the choice of nodes, and the method of calculating the parameters of the MC elements are described. A methodology for the theoretical study of measurement errors has been developed, and the results of their calculation for the implemented version of the meter are presented. It is substantiated that the relative measurement error of the developed device for small linear displacements does not exceed 0.065%. Ensuring high measurement accuracy is also due to the use of phase signals instead of potential-current signals.

Sideband Harmonic Suppression Analysis Based on Vector Diagrams for CHB Inverters Under Unbalanced Operation

Unexpected sideband harmonics of the cascaded H-bridge (CHB) inverters will appear in unbalanced conditions among cells and may result in harmonic pollution and even harmonic resonance. The linear controller to suppress the output voltage distortion is destined to be ineffective due to the non-linear characteristic of sideband harmonics. Focus on this problem, this article proposes a closed-loop harmonic suppression method by adjusting the phase-shift angles for the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> -cells CHB inverter. The harmonics suppression mechanism is revealed from a vector synthesis point of view. No complicated trigonometric function calculations and optimization algorithms are required. This method can achieve the suppression of the harmonic distortion around any multiplicative switching frequency. Phase-shift angles are adjusted continuously in real-time. The superior harmonic performance achieved by the proposed method is verified by the simulation and experiment results.

Model Based Switching Frequency &amp; Secondary-Side Phase Shift Angle Matching for Optimizing Efficiency of PV Microconverter

Model Based Switching Frequency &amp; Secondary-Side Phase Shift Angle Matching for Optimizing Efficiency of PV Microconverter

IMPEDANCE ANALYSIS FOR FOUR TYPES OF MINERAL WATER AND AQUADES USING ELECTRICAL IMPEDANCE SPECTROSCOPY (EIS) AT FREQUENCIES OF 1 Hz - 50 kHz

The Electrical Impedance Spectroscopy (EIS) method can be used to identify minerals in mineral water. The EIS method measures the impedance of a material by injecting alternating current in a certain frequency range, which is non-invasive and non-destructive. This study aims to analyze the impedance of mineral water and aquades based on the influence of the dissolved content using EIS equipment that provides flexibility in adjusting the desired frequency spectrum. The study used a frequency range from 1 Hz to 50 kHz with a four-electrode configuration. The measurement graph results were analyzed using Bode graph with impedance plot and phase shift angle to determine the impedance characteristics of mineral water. Equivalent circuit modeling helped to identify the electrochemical properties of materials such as the Warburg circuit, Constant Phase Element (CPE), and Randles circuit. The results show that the aquades has a higher impedance compared to the four mineral waters. Additionally, the four mineral waters exhibit varying impedances, attributed to their respective mineral content. Mineral water is characterized by an impedance that is dominated by Warburg impedance (Zw) at low frequencies, charge transfer resistance (Rct) and double layer capacitance (Cdl) at middle frequencies, and electrolyte resistance at high frequencies. However, the impedance of aquades dominated by electrolyte resistance (Re) at low frequency and Re+Rct at high frequency.

Impedance of nanocomposite SiO2(Si)&amp;FexOy(Fe) thin films containing Si and Fe nanoinclusions

In this study, electrical properties at alternating current of the nanocomposite films containing silicon and iron inclusions in amorphous SiO x matrix are presented. The composite SiO 2 (Si)&amp;Fe x O y (Fe) films were obtained using the ion-plasma co-sputtering of Si and Fe targets in oxygen containing atmosphere (Ar + O 2 ) followed by temperature annealing. It was revealed the predominance of the inductive contribution over the capacitive one in the reactive part of the admittance (impedance) at low frequencies (f &lt; 1 MHz) both after annealing in air and nitrogen atmosphere. The frequency dependences of the admittance after heat treatment in air have the minima that shift to the region of high frequencies with increasing the annealing temperature. In the case of low- frequency dependence, the phase shift angle passes into the region of positive values, which indicates the predominance of the inductive contribution to the admittance at these frequencies. The dependence of the conductivity real part at the alternating current frequency does not change significantly up to ~20 kHz. Starting from the frequency higher than ~20 KHz and up to ~1 MHz, the exponent in the frequency dependence of the conductivity lies within the limits m ~ 0.49…0.52.

Research on Changes in the Phase Shift Angle and Admittance of the Cellulose–Bio-Oil Composite under the Influence of Increasing Moisture during the Long-Term Operation of Power Transformers

In this study, the temperature–frequency dependencies of the pressboard–bio-oil–water nanoparticle composite’s fundamental parameters—phase shift angle and admittance—were examined using the Frequency Domain Spectroscopy method. Measurements were conducted in a frequency range of 10−4 Hz to 5 × 103 Hz at temperatures ranging from 293.15 K to 343.15 K, with a step of 10 K. The temperature stabilization accuracy was less than ±0.05 K. A total of 15 Arrhenius plots were determined for various phase shift angle values, from which 15 values and the average activation energy of relaxation time were determined. Similarly, the values of the activation energy of admittance relaxation time and the activation energy of admittance were determined. It was established that all three average values are identical within the bounds of uncertainty. Based on 45 values, a generalized activation energy was determined, with a value of ΔW ≈ (1.032 ± 0.0196) eV. Using the generalized activation energy value, the phase shift angle curves determined for all temperatures were recalculated to a temperature of 293.15 K. It was found that after conversion, all curves perfectly overlap. A similar operation was carried out for the frequency dependencies of admittance. In this case, too, the recalculated dependencies perfectly match. This means that the shape of the frequency dependencies of the phase shift angle and admittance depends solely on the moisture content in the pressboard–bio-oil–water nanodrop composite. The position of the curves in doubly logarithmic coordinates depends only on temperature and is determined by the generalized activation energy Using the generalized activation energy determined in this study will allow for the development of accurate methods for estimating moisture content in cellulose insulation of power transformers containing bio-oil. This will contribute to the detection of critical moisture content, which is about 5% by weight, and to the elimination of the risk, associated with such a high moisture content, of catastrophic failure of power transformers.

Analysis of harmonics currents in the case of grid connected photovoltaic generator

&lt;p&gt;&lt;span lang="EN-US"&gt;Nowadays, electrical grid experiences an increase in penetration of single-phase PV generations. Then, it becomes necessary to control this penetration by techniques of synchronization in order to provide electrical energy of good quality to the network. Estimation of the frequency, phase and magnitude of the grid voltage are necessary to correctly synchronizing the PV generator with grid. Connecting a direct current generator to grid via an inverter, requires to fix the performances to improve in the inverter to choose the best-suited topology. This paper describes the control of a non-isolated single-stage single-phase grid-connected inverter fed by a photovoltaic source. In order to define the influence of the three parameters: modulation index, switching frequency and phase shift angle, it is interesting to know the behavior of the system when one of these parameters moves away from its optimal value. Optimal values make it possible to obtain a THD as small as possible to satisfy the international standard. In this work, modulation index and switching frequency are set to their respective optimal values. To study grid current and inverter currents before and after filtering, harmonic analysis is performed for seven shift angles for the same switching frequency (10000 Hz) and modulation index (2.2).&lt;/span&gt;&lt;/p&gt;

Modulated Coupled Inductor-Based IPOP-DAB Converter With Optimized Modulation Trajectory Considering the Phase-Shift Angle Between Submodules for SST Applications

Modulated Coupled Inductor-Based IPOP-DAB Converter With Optimized Modulation Trajectory Considering the Phase-Shift Angle Between Submodules for SST Applications

Analysis of Converter-Fed Rotor Based Induction Machine

Abstract: This paper presents the analysis of an induction-machine with a concept of the rotor-fed by a converter. Statorwinding configured in star and connected to the input-side of the three-phase voltage-source, whereas rotor-windings are fed by back-to-back converter by means of DC-link capacitor. For this, the Induction-machine is modelled in MATLAB/Simulink and simulated with and without a converter. The rotor circuit is magnetized with the help of back-to-back converter which in turns supply the variable-reactive power by setting the different phase-shift angle between the converters. The results depict the enhancement of Power-factor and also presents the dynamic performance of the machine includes the loading and de-loading as well as the starting condition of the machine. Fundamental-frequency variations of the converter enhance capability of machine to operate at a constant-speed with variable-load operation. Impact of variation in phase-shift angles between the converters on the power-factor, reactive-power, stator and rotor-current are also presented.