High Total Harmonic Distortion Research Articles

High-Frequency Modified Bridgeless AC-DC PFC Rectifier for Ceiling-Fan

High current percentage total harmonics distortion (%THD), low supply power factor (SPF), and high input-power are main concern in an existing brushless direct current motor ceiling-fan (BLDCMCF). This paper presents AC-DC coupled-inductor-based bridgeless switched-inductor Cuk-converter (CIB-BLSICC) for BLDCMCF to address these concerns. CIB-BLSICC improves supply power quality (SPQ) and reduces input-power. Switched-inductor branch using coupled-inductor provides high-step-down-gain (HSDG), which offers an appropriate operating duty for BLSICC. Front-end CIB-BLSICC is developed in discontinuous mode (DCM) with changeable output voltage and a low component count, which reduces converter's overall size. DCM design offers auto power-factor correction (PFC) at a supply-mains. Variable output-voltage makes voltage source inverter (VSI) control easy (offers inverter switching at fundamental-frequency) with low switching-losses and helps speed-control. In addition to improving CF's (ceiling-fan's) overall efficiency, bridgeless design of PFC-converter lowers losses caused by conduction. Using reference speed of fan, CIB-BLSICC calculates its operational duty in order to create fixed-frequency PWM-pulses (200 kHz) while supply-voltage remains constant. This simple-control brings CF's price down by removing need for a sophisticated sensing-circuit, a DC-link sensor, and a voltage-controller. Test results confirm concept and design, which demonstrate a %THD of 1.483%, a crest-factor of 1.48, SPF of 0.9991, and a power-input of 27.93 W.

A piezoelectric MEMS microphone with proof mass and its array

Piezoelectric MEMS microphones (PMMs) have attracted increased attention in home automation, wearable devices and autonomous driving, since the high linearity, dustproof and waterproof, and easy manufacturing. In this paper, a hexagonal PMM with proof mass and its array in parallel are proposed using a 20 % Scandium-doped Aluminum Nitride (ScAlN) thin film on a Silicon-on-insulator (SOI) wafer. The theoretical analysis, simulation, fabrication and verification test were discussed. The performance of the devices was simulated using the finite element simulation, and the resonant frequency is 102.85 kHz. The sensitivity of element and its array were measured up to −68.3 dB and −68.4 dB, respectively (re: 1 V/Pa). And the sensitivities of the element and array were −38.6 dB and −37.9 dB at 1 kHz (re: 1 V/Pa) after amplification and filtering. The SNR of the array was increased to 55.3 dB since the increased capacitance of array. Besides, the total harmonic distortion (THD) was measured 1.7 % and 1.14 %, respectively. The PMM and its array with high SNR and good THD is suitable to commercial acoustic fields, especially the high-noise scenarios.

Optimized integration of renewable energy sources using seven-level converter controlled by ANFIS-CS-GWO

The global energy landscape is undergoing a significant transformation, driven by the need to reduce greenhouse gas emissions, enhance energy security, and provide sustainable and clean power solutions. Renewable energy sources (RES) such as Solar Photovoltaic (SPV), wind, fuel cells, and tidal power play a crucial role in this transition due to their abundant availability and low environmental impact. However, integrating these diverse energy sources into power systems requires advanced control strategies to ensure stability, efficiency, and reliability. Existing systems, however, face significant challenges such as unstable voltage profiles, prolonged fault settling time (FST), and high total harmonic distortion (THD), which compromise their efficiency and reliability. To overcome these limitations, a novel methodology is proposed, integrating Solar PV (SPV), wind, fuel cell, and tidal energy sources into a seven-level converter (SLC) system, which is named as Four Level RES based SLC (FLRES-SLC) system. This system is managed by an Adaptive Neuro-Fuzzy Inference System (ANFIS), fine-tuned by Cuckoo Search adopted Grey Wolf Optimizer (CS-GWO). This hybrid control strategy ensures a robust voltage profile, significantly reduces FST, and lowers THD, thereby markedly improving the overall performance of the converter system. The innovative approach offers a reliable and efficient solution for modern power systems, enhancing their integration with diverse RES and ensuring high-quality power delivery.

SUIVI DE LA QUALITÉ DE PUISSANCE MAXIMALE D'UN GÉNÉRATEUR D'INDUCTION À DOUBLE ALIMENTATION BASÉ SUR UN CONTRÔLEUR DE RÉSEAU NEURONAL ARTIFICIEL POUR SYSTÈME DE CONVERSION D'ÉNERGIE ÉOLIENNE

Renewable energy sources are playing a crucial role in satisfying the upcoming energy source needs for the world. The current power system is power electronics converter based, with several non-linear loads and spotted generations of renewable energy sources, resulting in many power quality issues. Most existing research analyzed MATLAB simulations and presented a high Total Harmonics Distortion (THD) level. This research work proposed an artificial neural network (ANN) control technique for a doubly fed induction generator (DFIG) based wind energy conversion systems (WECSs). To decrease chattering phenomena during the excitation arrangement, an advanced controller works for adaptive modification of the irregular power gain, even preserving the strength of the closed-loop scheme. The proposed PI controller one step forward improves reliability and tracks maximum voltage from the pulse width modulation rectifier. At primary, the modeling of the DFIG was presented. Then, using the proposed ANN controller, the rotor magnitude was tuned to recognize vector control of active and reactive power. The converter intends to activate at unity power factor and provide input currents with adequate harmonic content. The interface between the power’s electronic converter and the DFIG pulls out the most real power potential. The proposed prototype hardware model and simulation results are verified.

CHBMLI based DSTATCOM for power quality improvemt in a three-phase three-wire distribution system with PI controller

This paper presents a cascaded h-bridge (CHB) multilevel inverter (MLI) based MLI based distribution static synchronous compensator (DSTATCOM). The main objective of this paper is to reduce source current harmonics in the distribution system by using a cascade H-bridge multilevel inverter (CHBMLI) as DSTATCOM with a proportional-integral (PI) controller. The PI controller compensates reactive power, reduces source current harmonics, and maintains the unity power factor in the distribution system. The conventional two-level inverter-based DSTATCOM has many disadvantages such as high total harmonic distortion (THD), and high switching stress power semi-conductor devices, suitable for only low-power applications. This paper to overcome these drawbacks by using MLI-based DSTATCOM. The proposed system simulations are verified in MATLAB/Simulink software. The verified results are source current, load current, and compensating current.

A new topology of non-isolated AC-DC quadratic boost converter with enhanced power traits

A novel AC-DC quadratic boost converter (QBC) topology is presented in this paper which can provide higher power factor (PF), lower total harmonic distortion (THD) and higher voltage when compared to a conventional AC-DC boost convertero This is achieved by using additional switched capacitor and switched inductor in the power processing stage. The presented converter is analyzed theoretically, and a voltage gain equation is derived. A simulation model is created to evaluate the converter performance under various duty cycles, switching frequency, and changing output load. The input PF, THD, and voltage gain of the simulated model were compared with conventional converter to determine the validity of the suggested converter circuit. The results show that the efficiency, PF, THD and voltage gain value reaches approximately 97.9%, 0.98, 16.14, and 2.83 respectively at a duty cycle of 50% with fixed output load of 100 Ω. A dual loop voltage and current controller is also arrayed with the proposed circuit which allows further enhancement in PF (0.997) and THD (7.45%). This converter can be a suitable option for systems where isolation is not necessary but high PF, high voltage gain and low THD are required.

Hierarchical Control of AC/DC Hybrid Microgrid Based on Primary Model Predictive Optimization and Secondary Switching Control

The fluctuating characteristics of renewable energy generation in hybrid AC/DC microgrids, combined with timevarying loads, can result in high total harmonic distortion (THD) and distorted output voltage and current waveforms. To address these issues, a faster and more comprehensive primary and secondary hierarchical control method is required. In this paper, a faster model predictive optimization algorithm is introduced as a primary control method to predict operational states in advance, maintain a low THD state, and reduce the impact on power quality. Then, a secondary switching control is added to correct frequency and power allocation errors caused by primary control, recover microgrid voltage and frequency to their rated values, and ensure stable reactive power. Finally, simulation and comparison results prove the proposed method's effectiveness and applicability.

Efficiency and PF Improving Techniques with a Digital Control for Totem-Pole Bridgeless CRM Boost PFC Converters

A totem-pole bridgeless boost converter is one of the most promising topologies for the power factor correction (PFC) stage in high-power applications due to its high efficiency and small number of components. However, due to the totem-pole structure of the field-effect transistor (FET), very high switching loss occurs via the reverse recovery current of the body diode. To solve these problems, critical mode (CRM) control is a good solution to achieve the valley switching technique. With valley switching of CRM control, the switching loss decreases drastically with decreasing turn-on voltage. But, although the CRM control enables valley switching, it is hard to make an exact valley switching control with general zero-voltage detection circuits. In addition, when a frequency limitation scheme is applied to prevent a very high frequency, the switch can operate with hard switching at the boundary of the frequency limitation. Furthermore, the CRM boost PFC has a low PF and high total harmonic distortion (THD) under light-load conditions due to the large negative current resulting from resonance between the inductor and parasitic capacitance. It becomes worse at near-zero input voltage since the resonance current becomes larger near zero-input voltage. Therefore, in this paper, a totem-pole bridgeless boost PFC converter with high efficiency, high PF, and low THD is developed using TMS320F28377 by Texas Instruments. Based on the basic digital structure of the totem-pole bridgeless converter, the proposed controls help with exact valley switching, PF and THD improvement, and frequency limitation. The prototype converter is verified using 90–264 VAC input voltages and 450 V/3.3 kW output specifications.

Frequency Modulation Scheme for CCM Boost PFC Converter to Improve THD in Light-Load Condition

This study proposes a novel frequency modulation scheme for a continuous conduction mode (CCM) boost power factor correction (PFC) converter. The aim is to improve the total harmonic distortion (THD) under light-load conditions. Boost converters are widely utilized with CCM control for the PFC stage owing to their ability to achieve high efficiency with minimal components. In addition, they have a high power factor (PF) and low THD. However, despite being designed for CCM operation, the boost PFC converter transitions into discontinuous conduction mode (DCM) as the output load decreases. This mode, known as mixed conduction mode, degrades the PF and THD of the PFC converter. To address these issues, we propose a novel frequency modulation scheme. The CCM boost PFC converter adopts frequency variation to reduce the DCM region. To validate the feasibility of the proposed concept, a prototype with a 60 Hz/230 Vac input and 850 W/380 V output was utilized. Consequently, the boost PFC converter attains a high PF and low THD with simplified circuits.

Modified direct torque control algorithm for regeneration capability of IM driven electric vehicle by using hybrid energy storage system

The direct torque control (DTC) algorithm of a 3-phase voltage source inverter (VSI) has been implemented to drive induction motor (IM) for EV applications. However, the conventional DTC for IM is distressed due to large torque ripple, high current total harmonic distortion, and variable switching frequency. So, in this manuscript, a modified direct torque control (MDTC) algorithm is proposed to tackle the said challenges. A three-level hysteresis controller is proposed in modified DTC to optimize the duty ratio of the fundamental voltage vector to minimize the error between the reference and final voltage vector imposed on IM terminals. To improve the efficiency of the EVs by developing a system that uses the energy produced during regenerative braking. The proposed method recovers electric energy produced by the EV without using any additional power converter. The switching patterns allow power flow in both directions. Later, a hybrid energy storage system (HESS) is integrated to supply and store the energy in an optimal way. Extensive studies have been performed to show the efficacy of the proposed MDTC technique in IM based EV application with HESS. The key findings indicate that the proposed MDTC provides better dynamic and steady-state performance.

Study of PLL less DSGTP System using band-pass filter and APC (active power coefficient) control

This paper represents a study on a grid-tied photovoltaic (PV) system connected to a non-linear load. The system includes a PV array, a boost converter, a voltage source inverter (VSI), and a coupling inductor for grid connection. The maximum power point tracking (MPPT) mechanism based on Perturb and Observe (P&O) method which is used to control the duty ratio of the boost converter. Synchronization is achieved through a second-order band-pass filter instead of a Phase Locked Loop (PLL). However, the non-linear load causes poor current quality, leading to a high Total Harmonic Distortion (THD) in the grid current, which may affect the sinusoidal nature of the grid current and other connected loads. To address the harmonics problem, an Active Power Coefficient (APC) control technique is implemented to control the PV inverter gate pulse. The proposed model has been simulated in Matlab/Simulink, and system output parameters are analysed graphically. The simulation results indicate that the proposed approach maintains the total harmonic distortion (THD) of the grid current below 5% even in changing weather conditions, which satisfies the IEEE 519 standard.

Novel Asymmetric/ Symmetric Half-Cascaded Multilevel Inverter for photovoltaic based shunt active power filter to mitigate power quality issues

Photovoltaic (PV) technology has been recently developing and upgrading with regard to the rapid and high request from various agricultural, domestic and industrial electric power systems. Due to feasibility and reliability of Multi-Level Inverter (MLI), it can be effectively implemented in the photovoltaic systems. The large number of switches used in the MLIs is their main drawback which leads to lack of cost-effectiveness and high Total Harmonic Distortion (THD). In this paper, a novel Asymmetric/Symmetric Half-Cascaded MLI (ASHC-MLI) which contains low number of switches is proposed to attain a cost-effective structure. After that, PV panels have been used as power sources of this structure to construct the overall Shunt Hybrid Active Power Filter (SHAPF) for mitigating the power quality problems. To evaluate the cost-effectiveness of the proposed ASHC-MLI, it has been compared with the prominent and inventive MLI structures in both asymmetric and symmetric statuses. Meanwhile, the understudy power system has been affected by different current distortions so that the harmonic elimination capability of the proposed SHAPF can be well revealed. The evaluation analysis has been simultaneously performed for the conventional active power filter to appropriately validate its harmonic elimination capability.

Adaptability enhancement of fractional‐order LLCL‐type grid‐connected inverter to weak grid based on grid voltage weighted feedforward scheme

SummaryGrid‐connected inverter with a novel fractional‐order LLCL filter has the advantage of high grid current tracking accuracy and low total harmonic distortion without passive or active dampers, and the grid voltage full feedforward scheme is an effective method to improve the quality of grid current. However, due to the digital control delay, the suppression of the grid current harmonics is weakened, and the inverter output impedance has an additional negative phase shift, which deteriorates the stability of grid‐connected systems under weak grid. In this paper, a weighted grid voltage fractional‐order feedforward control scheme is proposed based on a quasi‐proportional resonant (QPR) controller, which introduces two weighting factors in the full feedforward path of the grid voltage and compensates the phase lag of the output impedance by designing appropriate weighting factors. Then, an improved scheme combining the QPR controller with a phase compensator is presented. As a result, the suppression ability of grid current harmonics and the adaptability to grid impedance variations are enhanced. Simulation and experimental results verify the effectiveness of the proposed grid voltage fractional‐order weighted feedforward scheme.

A data fusion control-based broad-band and high-dynamic excitation generation method for calibrating the low-frequency linear vibration sensors

The low-frequency vibration sensors are widely used for monitoring vibration in various engineering, and their sensitivity must be calibrated in order to ensure monitoring performance. Currently, the linear shaker is usually applied to provide an excitation for calibrating the sensors. However, this calibration process has the disadvantages of narrow low-frequency range, low signal-to-noise ratio (SNR), and high total harmonic distortion, which severely limits the improvement of calibration ability. In this study, a data fusion control-based broad-band and high-dynamic excitation generation method was proposed, which provides the linear excitation with broad-band high-dynamic for the sensors to achieve high-performance calibration. The simulations demonstrate that the amplitude attenuation and noises can be effectively eliminated in the range of DC (quasi-static)-150 Hz. The comparison experiments with the shaker show that the proposed method has the ability to generate high-dynamic and low-distortion excitation acceleration in 0.01–5 Hz and improve the SNR 40 dB of the excitation. Moreover, the low SNR of the sensor output signal is also well suppressed.

A Modified Indirect Current Vector-Controlled CHB Three-Level Inverter-fed Induction Motor Drive for Electric Vehicle

Low-cost electric vehicles (EVs) prefer induction motor (IM) based drive systems which are mostly operated with 2-level inverters (2LIs) because they require fewer component counts and minimum control complexity. While an IM operated with 2LI has a higher total harmonic distortion (THD) and lower efficiency. An indirect current vector control (ICVC) scheme is an effective and simplest control scheme used for IM of EVs. This ICVC scheme required one speed sensor and three current sensors which increased its cost and control complexity. Therefore, in this paper, a cascaded H-bridge 3-level inverter (CHB-3LI) fed IM drive (IMD) is presented. A modified ICVC scheme having only one speed sensor is presented and used to control the CHB-3LI fed IMD. The steady-state and transient performances of CHB-3LI fed IMD with the modified ICVC scheme are analyzed through simulation in MATLAB Simulink and validated through experiments on a developed laboratory setup.

Reduction of Spurious Switching in Direct Vector Quantized Space Vector Pulse Density Modulation Scheme for Multilevel Inverters

A generalized online switching scheme for multi-level inverter based on Direct Vector Quantized Space Vector Pulse Density Modulation (DVQSVPDM) suitable for adjustable speed drive is proposed in this article. The existing DVQSVPDM schemes have spurious switching as the voronoi region is determined from integrated error vector of Sigma Delta Modulator (SDM). This results in high Total Harmonic Distortion (THD) of Common Mode Voltage (CMV) at lower modulation index. In the proposed DVQSVPDM the nearest three space vectors to the reference vector forms the triangular voronoi region. The integrated error vector of SDM is quantized to its nearest space vector in the voronoi region to generate the switching vectors. This reduces spurious switching associated with DVQSVPDM schemes and improves the performance at lower modulation index by reducing THD of CMV. The proposed scheme works for all n-level inverter topologies and the computations required remain same irrespective of level of inverter. Redundant states of switching vectors are not considered for switching which results in the discontinuous nature of proposed scheme. The performance of proposed DVQSVPDM is compared with space vector based modulation schemes and third harmonic injected sine PWM scheme and the results are presented. The proposed scheme is experimentally validated for a 3hp open end winding induction motor fed with three-level inverters on both sides.

A High-Performance Isolated Bridgeless Resonant SEPIC PFC Converter at Medium Line Frequencies

Due to the characteristics of high power factor and low total harmonic distortion (THD) in discontinuous conduction mode (DCM), the power factor correction (PFC) converter based on isolated single-ended primary-inductor converter (SEPIC) is more suitable for medium-line-frequency avionics applications. However, the inherent defects of isolated SEPIC PFC converter such as the voltage-spike issue and the hard-switching operations of semiconductor components severely limit the utilization of such topologies. In this paper, a high-performance isolated bridgeless resonant SEPIC PFC converter is proposed. Instead of typical SEPIC-type operational mode, the proposed converter operates in resonant mode, and hence, all switches and diodes in this topology can achieve soft switching and the voltage-spike issue is effectively solved. Moreover, different from the existing isolated SEPIC PFC converters, the transformer in this topology can transfer energy through the whole switching cycle, which greatly improves the core utilization. The overall performance of the proposed topology is illustrated in terms of its working principles, control scheme and the parameter design considerations. Finally, the analysis is validated by a 400-Hz experimental prototype with soft-switching capability.

Comparative Study of Passivity, Model Predictive, and Passivity-Based Model Predictive Controllers in Uninterruptible Power Supply Applications

Voltage source converters are widely used in distributed generation (DG) and uninterruptible power supply (UPS) applications. This paper aims to find the controller that performs best when model changes occur in the system, showing insensitivity to parameter variations. A comparison of the finite control set model predictive controller (FCS-MPC), interconnection and damping assignment passivity-based controller (IDA-PBC), and passivity-based model predictive control (PB-MPC) reveals that the PB-MPC provides high resistance to these unexpected LC filter changes in the converter. The second aim of the paper is to reduce the total harmonic distortion (THD) of the output voltage of the three-phase voltage source inverter (VSI). A high total harmonic distortion (THD) value exists in the voltage waveform of the three-phase voltage source inverter (VSI), feeding a non-linear load. A MATLAB simulation was performed using three control techniques for a three-phase VSI feeding: linear load, unbalanced load, and non-linear load. The PB-MPC performs better than the FCS-MPC and IDA-PBC in terms of having a low THD value in the output voltage of the converter under all types of applied loads, improving the THD by up to 30%, and having low variation in THD with mismatched filter parameters, as shown in the bar charts in the results section. Overall, the PB-MPC controller improves the robustness under parameter mismatch and reduces the computational burden. PB-MPC reduces the THD value because it integrates power shaping and the injection of damping resistances into the VSI.

Design of Hybrid multi-level inverter for photovoltaic(PV) application

Nowadays the demand and consumption of energy increase in the word. Due to high cost of fossil fuel it’s not able to meet the required power generation demand. But the developed and developing countries encourage to generate power from renewable energy sources. The developed countries manage their resources in such a manner that they will fulfill their needs today and in the future as well. Nevertheless, the developing countries have limited sources of fossil fuels, which may decrease day by day. For this problem, the alternate solution is required, which is renewable energy. The output of renewable i.e. photovoltaic (PV) is DC. Now this is a challenging task for the researcher to integrate the renewable energy into the ac grid. For the reliable future of the power system, it is imperative for the modern era to integrate non-conventional sources into the AC power grid.The use of photovoltaic cells is increasing dramatically in all areas of life because of their small environmental impact, pollution-free, minimal maintenance, and zero noise. The real work focuses on the integration of PV systems with the proposed new topology called Multi-level inverters based on switch dc sources for low, medium and high power applications. An inverter is a power electronics device that converts DC input to AC output voltage. Input DC voltage is obtains from PV cell array, fuel cell or any other source.The output of PV panels is use as DC input voltage source for the proposed inverter. Single-phase multi level inverter is use to convert dc power receiving form PV array to AC power. First single phase two level inverter introduce which have many problems like those that high value capacitor required at output and high total harmonics distortion’s (THD). Nevertheless, as the number of level increased in inverter output the number of electronic switches also increased which may increase the losses.Multi-level inverters are gave more attention for high power applications. In recent years, lower order harmonic components has been developed to operate at higher switching frequencies.On the other side as the number of level increased the output waveform approach to sinusoidal waveform and the harmonics decreased. Output voltage and current waveforms are obtains and THDs are analyze. The multi-level inverter used in un-interrupted power supply (UPS), variable frequency drives (VFD), pumps etc. The performance of single-phase multi-level inverter will be analyzed in MATLAB / Simulink software.

Power Quality Improvement and Harmonics Compensation Using Hybrid Filter

The need for electricity is expanding at an even faster rate in these modern times. In order for the electrical devices to function properly and effectively, a constant supply of high-quality power is required. The most common types of power quality reducing factors include noise, interruptions, variations in voltage and frequency, and so on. These factors all contribute to a decrease in the electrical devices' overall efficiency. Total harmonic distortion (THD) was made worse by the presence of non-linear loads. The existence of harmonics is the primary cause of the problems that lead to the breakdown of insulation, excess heating, and a shortened lifespan for various pieces of equipment. In addition to this, if there is a high THD in the electrical system, it may cause the energy meter to give inaccurate readings. An economic hybrid filter can be employed to reduce the losses caused by harmonics distortion, thereby providing a solution to those issues. This paper provides an in-depth look into the application of this filter for harmonic compensation. By performing simulations with the Simulink tool of MATLAB and validating the results using the experimental setup, it has been determined that using a filter can reduce the total harmonic distortion (THD) of the current by 40.09 percentage points, which will result in better power quality and energy conservation. The IEEE Standard 519-1992 was consulted as a reference when making this determination.