Total Harmonic Distortion Analysis Research Articles

Investigations of BLDC motor speed characteristics via THD under conventional and advanced hybrid controllers

This project investigates brushless direct current (BLDC) motor speed control through total harmonic distortion (THD) analysis, employing proportional integral (PI), fuzzy logic (FLC), adaptive neuro-fuzzy inference system (ANFIS), and an innovative hybrid ANFIS-PD/PI controller. Considering the vital role of BLDC motors in precision-dependent industries like robotics, electric vehicles, and industrial automation, our primary focus is on understanding BLDC motor operation and recognizing THD's significance as a performance metric. Controllers are meticulously implemented in real-time, fine-tuned, and optimized to achieve desired speed characteristics, incorporating considerations like response time, accuracy, and energy efficiency. The project's core involves THD analysis, quantifying harmonic content in the BLDC motor's speed waveform. This facilitates a comprehensive comparative evaluation of controller performance, assessing their capability to maintain speed stability and influence power quality. The discussion covers the merits and limitations of each controller, with a special emphasis on the hybrid ANFIS-PD/PI controller, seamlessly blending ANFIS adaptability with PD/PI control stability. Results illustrate the hybrid controller's excellence in optimizing BLDC motor speed control, demonstrating superior performance in speed accuracy, disturbance rejection, and THD reduction. These findings drive advancements in motor control technology, providing practical guidance for selecting controllers tailored to specific application requirements. Simulation results can be analyzed using MATLAB/Simulink 2018a Software.

Advanced testbed to assess disturbances in electrical grids with DERs using relays/meters with varying sampling frequencies

Distributed energy resources (DERs) are vital to achieve clean energy goals, but in some cases, their rapid deployment has led to negative effects on their reliability because of possible voltages and/or current disturbances that need to be analyzed in detail. This study created an advanced testbed with a real-time simulator and synchronized time and trigger event systems was created to compare event disturbances from intelligent electronic devices (IEDs) with different sampling frequencies and locations in an electrical grid containing DERs. This testbed is capable of capturing the recorded events of multiple IEDs and the real-time simulator to assess the effect of the disturbances and IEDs’ behaviors, including phase voltages, phase current waveforms, and total harmonic distortion (THD) analysis. In this study, a three-line-to-ground electrical fault was simulated, the disturbance event was detected, and recorded events (from 4 to 133 samples per cycle) were collected from meters and relays located at different sites. A harmonic peak algorithm, which was based on measuring the phase voltage and phase current THD peaks at the first one-cycle of the disturbance events, was created to assess and detect the fault states and locations. Several important findings resulted from performing this study, such as selecting IEDs with high sampling frequencies, installing all IEDs with similar sampling frequencies, assessing the software limitations for computing THD, studying the effect of the IEDs’ locations (downstream or upstream) with respect to the electrical fault site and the distance from the disturbance event point, evaluating the percentage errors of the phase voltage THD peaks at the first one-cycle of disturbance events, and installing synchronized time source and trigger event signal systems for recording the IEDs’ events.

Adaptive TS-ANFIS neuro-fuzzy controller based single phase shunt active power filter to mitigate sensitive power quality issues in IoT devices

The emergence of Internet of Things (IoT) offers numerous functions, such as intelligent sensor integration, remote sensing, and high-speed data transmission, which have found widespread applications in the smart industry and commercial applications. The associative nonlinear effects of a variety of undesirable power quality concerns were resolved by using harmonic mitigation in nonlinear loads and high-performance converters were built on power electronics in conventional systems. Among other performance objectives, total harmonic (THD) distortion analysis and higher order harmonics mitigation is given main concern in smart electronics equipment. This paper proposes an approach to minimize higher-order harmonics due to nonlinear load disturbances in smart IoT devices using the Takagi–Sugeno (TS) Neuro Fuzzy (TS-ANFIS) supervised shunt APF. The proposed work elicits the novel adaptive harmonic mitigation technique in hybrid IoT embedded systems to protect from malfunctioning and to deal with the uncertainty of harmonic signal stimuli in sensitive sensors-based IoT systems. Hysteresis current control is used for the ignition of reference signal under uncertainty of harmonic stimuli. The single phase shunt APF is used to mitigate higher-order harmonics from supply mains, while the implementation of TS-ANFIS supervises the controller action to generate a trigger signal for adequate single phase APF gate excitation. The higher order harmonic current data set is used for error deviation for training neural networks and adaptive control. The estimated adoption of the neuron's empirical weight reduces the total THD to a significant reduction rate of 72.8 % to 0.78 %. The control mechanism is feasible for a range of smart IoT systems to adhere to the standard of 519 (IEEE).

Realization of nth Order Wave Active Low-Pass Filter Using Differential Difference Current Conveyor

A wave active filter (WAF) based on a differential difference current conveyor (DDCC) is presented in this paper. An active filter formation depends entirely on wave quantity processing. The wave method is demonstrated for the basic wave active elements (WAEs) of active filters such as a series inductor and a shunt capacitor. The novelty of the proposed work is that the mathematical operations required to implement the wave active components, such as lossy integration-subtraction; subtraction; summation and inverter, are performed using the DDCC as an analog building block (ABB). Designing WAFs of lower to higher-order is extremely challenging, i.e., great motivation to propose a WFA using a CMOS-based DDCC for lower and higher-order low-pass Butterworth filter topologies. Additionally, the filter performances are verified through noise analysis, percentage total harmonic distortion (%THD) and Monte Carlo analysis. The proposed WFA is theoretically verified for [Formula: see text]th order low-pass Butterworth filter designs ([Formula: see text]) using DDCC-based WAEs and validated using SPICE simulations with [Formula: see text]m TSMC CMOS technology parameters for DDCC, operating on [Formula: see text][Formula: see text]V.

Investigation of the Effect of Airborne Contaminants on PEM Fuel Cell Stack Performance and Degradation Using Electrochemical Impedance Spectroscopy, AVL Thda™ and FTIR Gas Analyzer

Air pollution is still a bitter truth in many locations in the world. In highly populated regions like metropolitan areas as well as in agricultural areas there are various airborne contaminants which can be harmful to organisms. Also fuel cells, especially PEMFC are sensitive to airborne contaminants.In most mobile and stationary PEM fuel cell systems, ambient air is used as oxidant gas at the cathode of the fuel cell. It is cost and weight saving because there is no need to install additional tank for pure oxygen and to refill it, but the performance of fuel cell can suffer beyond the oxygen gain from airborne contaminants, which also have the potential to accelerate degradation. To prevent that airborne contaminants reach the fuel cell cathode, air filter systems consisting of particle filter and additional activated carbon filter are installed at the cathode inlet.The focus here is on the investigation of the use of AVL THDAtm method to detect effects of airborne contaminants. THDA (total harmonic distortion analysis) is a patented online fuel cell monitoring method based on analyzing harmonic distortion effects of voltage drifts instead of single cell voltage measurement. So far it was successfully demonstrated for the detection of water issues like flooding and drying, and for low media supply issues on both cathode and anode side [1, 2].For the development and validation of the method, experiments with a PEMFC stack are going to be done on a fuel cell testbed equipped with an AVL X-Ion impedance analyzer. Specific air pollutant gases ammonia (NH3), sulfur dioxide (SO2) and nitrogen oxides (NOx) are going to be mixed into the cathode air in the ppb range. Their effects on PEMFC stack performance are going to be investigated with electrochemical impedance spectroscopy (EIS) and total harmonic distortion analysis. The cathode exhaust gas is also going to be analyzed by an FTIR gas analyzer.It is planned to test the PEMFC stack under different operating conditions, with various parameters and different cathode gas mix ratios while monitoring possible conversion of impurities via FTIR and the stack state of health using THDA and conventional technologies to understand the link between the effect of airborne contaminants on fuel cell stack performance, on its lifetime and to determine possible early indicators in the THDA signals.

Numerical Simulation of the Carbon Deposition Mechanism of Solid Oxide Fuel Cells Based on Total Harmonic Distortion Analysis

Identifying the corresponding degradation mechanisms at the early stage of operation is important for the long-term stable operation of solid oxide fuel cells (SOFCs). This paper uses total harmonic distortion analysis (THDA) to identify the anode carbon deposition mechanism in the early stage of SOFC operation with carbon-containing fuels. An accelerated calculation model for the electrochemical impedance spectrum (EIS) and a total harmonic distortion calculation model were constructed to study the carbon deposition mechanism and carbon removal strategy of SOFC anodes based on a one-dimensional transient elementary reaction kinetic model of an SOFC fueled by a CH4/H2O mixture. It is shown that the THDA calculation model can identify the primary stages of carbon deposition on SOFC anodes at specific frequencies. The THDA profiles at frequencies greater than 2 kHz contain essentially the same key information as at lower frequencies, suggesting that THDA can significantly reduce the test time for identifying performance degradation in the early stages of SOFC operation compared to EIS. Using a mixture of hydrogen and water vapor to remove the solid carbon generated by the cell anode and restore it to its initial performance, the THDA computational model can successfully respond to this process.

A Novel Online Diagnosis Method for Tubular Solid Oxide Fuel Cells Using Total Harmonic Distortion Analysis

Fast and accurate online prognostic technology is urgently needed for the long-term and stable operation of solid oxide fuel cell (SOFCs). Total harmonic distortion analysis (THDA) is a potential candidate that obtains the dynamic information of an electrochemical system by analyzing high-order signals and has been successfully utilized in PEMFC fault diagnosis. In this study, the THDA method is utilized in a tubular SOFC under fuel and air starvation conditions at different hydrogen and air flow rates. The total harmonic distortion spectra are obtained in the frequency range of 0.1~100 Hz. The effects of different excitation current amplitudes on the results accuracy are further investigated. As a consequence, the excitation amplitude range, frequencies with high sensitivity and appropriate threshold are chosen to diagnose different faults efficiently.

Analysis of total harmonic distortion in single-phase single-stage grid-connected photovoltaic system

<p>This study presents the power quality issue mainly focus the effect of total harmonic distortion (THD) on a grid-connected PV system. Firstly, a grid-connected PV system with a single-phase single-stage has been developed to monitor the output values of voltage and current and also its harmonic distortion behaviours. Maximum power point tracking (MPPT) was implemented since it is proven as the first step for THD reduction because MPPT will extract maximum output power, voltage, and current of the PV system without fluctuation which leads to a low THD level. Furthermore, the employment of a good filter also reduces the THD level in a PV system. Thus, this study will focus on the THD analysis to resolve the power quality problems in the grid-connected PV system. The result shows that the THD value for current, <em>I<sub>THD</sub></em> analysis is more significant than the THD value for voltage, <em>V<sub>THD</sub></em> analysis in the case of grid-connected PV systems operating under different solar irradiances. In a conclusion, the increase in solar irradiance will increase the rated values of generated power and current thus, increasing the performance of THD values.</p>

A Magnetically Controlled Current Transformer for Stable Energy Harvesting

The magnetically controlled current transformer (MCCT) is proposed to harvest stable energy from the magnetic field induced by the transmission-line fluctuating current. Compared with the conventional current transformer (CT), the advance of the proposed MCCT originates from the so-called constant magnetic flux control, which is achieved by connecting an electronic load on the secondary side of MCCT, and adjust the load impedance to make it equivalent to the corresponding resistive-capacitive impedance for magnetization or demagnetization. Furthermore, the working principle and the excitation characteristic of the MCCT system have been analyzed using the equivalent magnetic circuit and equivalent circuit methods. In addition, the details of the electronic load circuit and control system of the MCCT are presented in this paper, and the stability of the system is verified using logarithmic criterion and total harmonic current distortion (THDi) analysis. Finally, the co-simulation and experimental results show that MCCT can produce a stable output power of 13 W in the range of 50–500 A current fluctuations, demonstrating that the proposed magnetic energy harvester is capable of a high conversion efficiency and output stability.

Improving Power Quality by DSTATCOM Based DQ Theory with Soft Computing Techniques

The development of non-linear loads at consumers has significantly impacted power supply systems. Since, the poor power quality has been found in the three-phase distribution system due to unbalanced loads, harmonic current, undesired voltage regulation, and extreme reactive power demand. To overcome this issue, Distributed STATicCOMpensator (DSTATCOM) is implemented. DSTATCOM is a shunt-connected Voltage Source Converter (VSC) that has been utilized in distribution networks to balance the bus voltage in terms of enhancing reactive power control and power factor. DSTATCOM can provide both rapid and continuous capacitive and inductive mode compensation. A rectified resistive and inductive load eliminates current harmonics in a three-phase power supply. The synchronous fundamental DQ frame is a time-domain approach developed from three-phase system space vector transformations has been designed using MATLAB/Simulink. The DQ theory is used to produce the reference signal for the Pulse Width Modulation (PWM) generator. In addition, a traditional Proportional Integral Derivative (PID) controller is designed and compared with proposed soft computing approaches such as Fuzzy–PID and Artificial Neural Network (ANN-PID) and compared accurate reference current determination for Direct Current (DC) bus through DC link. An Analytical explores the proposed control strategies given to establish superior outcomes. Finally, total harmonic distortion analysis should be taken for performance analysis of the proposed system with IEEE standards.

Application of PCCS Method to PV Generation System with Half Bridge Inverter

A Power Conditioning System (PCS) for a PV power generation system obtains the maximum power from a photovoltaic (PV) array by Maximum Power Point Tracking (MPPT), but losses in the inverter are a factor in lowering the power obtained by the MPPT. The generation of harmonic currents is also a problem for PCS. This paper proposes the application of the Peak Current Control Switching (PCCS) method in PCS for PV Generation System using a half bridge inverter. The half bridge inverter improves efficiency by reducing the number of switching elements and further suppresses harmonic currents by controlling them using the PCCS method. In this paper, a comparative simulation of the conventional Hysteresis Current Control (HCC) method and the proposed PCCS method is performed using a half bridge inverter. The results of harmonic analysis and comparative simulation of total harmonic distortion (THD) show that the PCCS method generates harmonic components near the switching frequency, and that the proposed PCCS method always has a lower distortion rate than the conventional HCC method.

Simulation of Flyback Converter in MATLAB with and Without the Use of Input Filter

Flyback converter belongs to a category of converters with isolation. This paper presents a simplest approach to simulate single phase AC-DC Flyback Converter with and without filter. The use of LC filter reduces the input frequency harmonics and the Total Harmonic Distortion (THD) is analyzed. The Flyback converter is used to step up the input voltage by varying the duty cycle. The use of Flyback Converter is preferred because of the simpler design and lesser number of components and simpler control strategy. This paper deals with the closed loop simulation of a Flyback converter and its THD analysis in MATLAB.

A quintuple phase shift modulation scheme in multilevel dual active bridge converter for battery energy storage system

SummaryGenerally, the dual active bridge (DAB) bidirectional DC‐DC converter suffers from harmonics in the high‐frequency link (HFL) conversion stage while operating under any modulation scheme. This paper proposes a quintuple phase shift (QPS) modulation scheme to suppress the harmonics under the whole operating range. A bidirectional auxiliary switch in the low voltage bridge produces a five‐level output, which alleviates harmonic components of HFL current. The total harmonic distortion (THD) analysis is done for various operating conditions and is compared with the conventional modulation scheme, such as single phase shift and dual phase shift. The THD can be reduced in the entire power transmission for the proposed modulation scheme by defining the suitable phase shift ratios. Also, the power flow analysis under QPS modulation is reported in this paper. To validate the proposed approach's theoretical performance, simulation results are obtained under different operating conditions and verified with experimental results. The QPS modulation is implemented using the Spartan 3AN FPGA processor.

Performance Evaluation of Fuzzy One Cycle Control Based Custom Power Device for Harmonic Mitigation

Custom power devices (CPDs) provide better harmonic minimization when they are connected in parallel with the distribution network. Power switches have a hard impact on harmonic production in distribution networks, which leads to aging effects. Techniques used to control CPD’s provide full switching in various ways. A pulse width modulation (PWM) scheme requires a reference frame transformation that tracks source and load currents to produce a control signal. The voltage de-coupler is installed in the power device's current controllers to minimize fast current harmonics and remove complexity. One-cycle control (OCC) operates in dual boost converter mode and requires only source currents to produce a control signal. Minimum distortions are obtained by the output voltage feedback compensator. The proposed approach compares the performance of two methodologies based on total harmonic distortion (THD) analysis of the same grid voltage. The performance of the CPD using PI and fuzzy one-cycle control techniques is illustrated by simulation, which gives accurate results.

Study of shoot-through control pulse generation for a Z-source converter with wind turbine energy system

In this paper, there is a discussion about different modulation schemes for a dc-to-ac ZSC, also named Z-source inverter (ZSI), for triggering the main switches of three-phase legs or poles of an inverter. A prototype of an 8.5-kilowatt wind turbine with a 5.8-kilowatt Permanent Magnet Synchronous Generator (PMSG) system employed with voltage-controlled ZSI is implemented in this paper. For voltage control of load side of a wind turbine generation system (WTGS), a Proportional Integral (PI) controller is used. Three types of PWM schemes namely simple boost pulse width modulation (SB-PWM), third harmonic injection boost control (THIBC-PWM) and the space vector pulse width modulation (SV-PWM) techniques are compared on the basis of total harmonic distortion of the output ac-waveform of the Z-source Converter (ZSC) to find out that, which modulation technique is the best fit for a ZSI integrated with WTGS. The pros and cons of these techniques are compared in terms of line-voltage harmonics, phase-voltage harmonics, phase-current harmonics and switching stress of switches with detailed simulation results. These different modulation techniques are implemented on the MATLAB-Simulink domain. From Total Harmonic Distortion (THD) analysis, simple boost control technique is found to be the most appropriate shoot-through control technique for a ZSI in collaboration with WTGS.

Total Harmonic Distortion (THD) analysis utilizing the FFT capabilities of modern digital storage oscilloscopes

Total Harmonic Distortion (THD) analysis utilizing the FFT capabilities of modern digital storage oscilloscopes

Optimal Power Flow Through Variable Frequency Transformer Using Different Optimization Techniques

For synchronous and asynchronous connectivity of separate power grids, phase shifting transformers (PST), the high-voltage-direct-current (HVDC) converters and variable-frequency-transformer (VFT) are viable options. Natural damping and high overloading capabilities are inherent in the VFT, which is critical for power grid reliability and stability. This article reports the optimal power flow across a power system involving the implementation of several meta-heuristic optimization techniques based control strategy. Several optimization techniques are applied to optimize the gains of proportional-integral-derivative (PID) controller which aids in regulating the system dynamic response. The firefly algorithm based PID controller performs better in contrast to other optimization techniques in improving the system dynamics. The DC motor accustomed with PID controller provides the required torque necessary for power transfer between two connected grids. Sensitivity analysis is exhibited to inspect the strength of developed power system against deviations in certain system parameters. A separate study is done for the asynchronous operation of VFT based power system using firefly algorithm with different DC motor torque. To validate the effect of VFT over HVDC total harmonic distortion analysis has been carried out to check for the harmonic content in the rotor and stator current of VFT.

THD analysis and cost comparison for an N-level H-bridge inverter incorporating passive and active filters

Multilevel H-bridge inverters have grown in popularity in electronic direct current (DC) to alternating current (AC) power conversion. In the renewable energy field, H-bridge inverters are used for converting DC voltage obtained from solar panels to AC voltage. However, H-bridge inverters produce undesirable odd harmonics in their output. Several H-bridges are, therefore, usually cascaded to reduce the total harmonic distortion (THD) in their output, but the results aren’t satisfactory in most cases. In this paper, both active and passive filters are incorporated in a cascaded H-bridge inverter to reduce the THD further. Then cost comparison is made of cascaded H-bridge inverters (3, 5, 7, 9, and 11-levels) without a filter and multilevel cascaded H-bridge inverters (3, 5, 7, 9, and 11-levels) with a passive filter or active filter. Powersim (PSIM) platform is used to perform the THD analysis.

Analysis of Total Harmonic Distortion and implementation of Inverter Fault Diagnosis using Artificial Neural Network

As power electronics devices dependability is very significant to guarantee Multi Level Inverter (MLI) systems stable functioning, it is imperative to identify and position faults as promptly as possible. Due to the fault occurrences, the Total Harmonic Distortion (THD) on the system gets a hit. In this perspective, to improve fault diagnosis accuracy and efficient working of a Cascaded Multi level Inverter System (CHMLIS), a quick and accurate fault diagnosis strategy with an optimized training algorithm using Artificial Neural Network (ANN) is presented. Also, Total Harmonic Distortion (THD) is analyzed for each switch Fault simulated using MATLAB/Simulink and the results are presented. Results shows the efficacy of Algorithm in identifying the fault. The auxiliary cell is replaced while the fault occurs in the main cell thus making the uninterrupted working of the Multi-Level Inverter (MLI) in the Induction Motor Drive (IMD).

30° Discontinuous PWM-Based Closed Loop Volts/Hz Control of Induction Motor Drive with Slip Regulation

This paper proposes 30° discontinuous PWM-based closed loop volts/Hz control of induction motor drive with slip regulation. The voltage source inverter is carried out with various pulse width modulation (PWM) schemes such as continuous PWM (CPWM) and discontinuous PWM (DPWM) schemes. The inverter's performance is affected by these PWM schemes. Therefore, this paper investigates the PWM schemes for the inverter. It aims to identify a best PWM scheme based on the total harmonic distortion and torque ripple analysis for constant volts/Hz induction motor drive amongst the various PWM schemes in open loop and closed loop and also proposes a 30° DPWM-based closed-loop control. The performance investigations of various PWM schemes based on inverter-fed induction motor have been evaluated analytically and using MATLAB/Simulink environment. Experimental results have been validated. The combination of 30° DPWM with PI control and slip regulation for induction motor makes the speed control system robust and ideal for low-accuracy applications.