Harmonic Filter Research Articles

Method for Calculating the Unbalanced Current in Ungrounded Double Wye C-Type Harmonic Filters

This paper presents a methodology to calculate the neutral unbalanced current in C-type filters with an ungrounded double Wye topology; this equipment is widely used in the steel sector to mitigate the harmonic content in electrical installations caused by electric furnaces used in metal smelting processes. A common failure in these filters is the current unbalance caused by the degradation of the capacitor and inductor modules, leading to dangerous surges that affect these components, possible harmonic resonances, and deficient filtering by the equipment. Currently, there are no documented strategies for calculating the neutral current that allow for the proper adjustment of neutral protection in this type of equipment, resulting in catastrophic failures, costly unscheduled shutdowns, and potential harm to plant personnel. In this paper, we propose a methodology for calculating the unbalanced current in double Wye C-type harmonic filters, considering the natural degradation of capacitor and inductor modules and based on on-site measurements of the impedances for each element of the equipment. This allows for the predictive maintenance of these devices and the precise adjustment of neutral overcurrent protection. First, we review the operating principle of C-type harmonic filters and the neutral protection scheme. Then, the calculation methodology is proposed and validated in two practical case studies. In the first case, a 45 Mvar C-type second harmonic filter connected to a 34.5 kV bus is analyzed. In the second case, an 18.5 Mvar C-type second harmonic filter, part of a ±80 Mvar STATCOM system, connected to a 34.5 kV bus is examined. In both cases, these filters reduce the harmonic content in two steel plants: the first connected to a 400 kV bus and the second to a 230 kV bus. The results obtained with the proposed methodology were implemented in the protection device for a neutral current imbalance, considering different degradation values of the capacitors, and compared with the manufacturer’s suggested settings. The discussion highlights the good performance of the proposed methodology, particularly in terms of the protection device’s response speed to a risky unbalanced current.

Power Quality Analysis of Electrical Installation at Commercial Center

For many years, power quality analysis has constantly been carried out at the power stations or sub-stations using the data collected at the data Centre of the power plant. However, this practice has proven to be erroneous and tedious to determine the exactly power quality problem especially when it comes to commercial facilities. Therefore, a revised approach of analysis for the power quality problems at the sites where they occur has been used in this research. This is because of the sensitivity of modern electronic equipment used in commercial facilities and also the need for accuracy of the data measurements carried out at the sites henceforth, with accurate data measurement, we can easily identify the power quality issues. Through-out this research, load unbalance of 28% was found. The solution to load unbalance was to balance the loads to 3,3% among the three phases and power losses caused by this unbalance current were calculated. Although the neutral conductor remained unchanged, harmonics especially triplen-harmonics was found to be more 10% recommended by IEC standards, therefore active harmonic filter of 200A was installed at the main panel board to reduce the losses caused by harmonics at the facility.

Improve power quality and stability of grid - Connected PV system by using series filter

As the world increasingly focuses on renewable energy sources, grid-connected PV systems will continue to play a critical role in meeting our energy needs. This integration has brought many benefits, but has also created various problems related to power quality and stability at the connection points. Various techniques are used to improve the power quality, such as passive filters, tuned passive harmonic filters, and active filters. This paper presents the use of a series active filter on the DC side of grid-connected PV systems to improve their power quality, stability, and dynamic performance. The proposed filter consists of an inductor, two capacitors, and four transistor-diode pairs, the operation of which is controlled by a sinusoidal pulse width modulation (SPWM) scheme. The MATLAB/Simulink is used to build and validate a comprehensive mathematical model of the studied system. The transfer function of the system is identified and its transient response is studied under various test input signals. A Bode plot is also generated to assess the impact of the integration of this component on the stability of the system. The results showed that incorporating the filter resulted in a significant reduction in the total harmonic distortion factor (Thd%) for both the voltage and current waves at the inverter output. Moreover, it improved the transient response characteristics of the system by significantly reducing the maximum overshoot value of the system response with respect to the test input signals. The results indicate that the stability of the system is improved after the filter addition, as evidenced by the increased gain margin and phase margin in the system Bode plot.

Design of a high-power harmonic waveguide filter for radar transmitter

In this article, we present the research results on the designing and manufacturing method of a high-power harmonic filter applied in the X-band transmitter system. The harmonic filter utilizes Waffle-iron filters and quarter-wavelength converters on the waveguide. As a result, the loss and ripple within the passband are improved, while meeting the requirements of cutting off high-order harmonics. Based on the application of microwave theory and simulation software tools, the research team have calculated, designed and manufactured a harmonic filter that meets all the requested specifications for application in X-band transmitter systems: Loss ≤ 0,12dB@8,9-9,6GHz; Reflection coefficient ≤ -20dB@8,9-9,6GHz; Frequency selectivity ≤ -40dB@2nd harmonic, 3rd harmonic, 4th harmonic.

Comparison of space vector and switching frequency optimal pulse width modulation for diode free F‐type multi level inverter

AbstractThis study presents a comprehensive examination of space vector pulse width modulation (SVPWM) and switching frequency optimal PWM (SFOPWM) for an F‐type multilevel inverter (FTMLI). SVPWM offers a simple, digital implementation for three‐phase, three‐level inverter structures, and carrier‐based SFOPWM allows for maximum use of switching frequency with a simple construction. This approach reveals the underlying relationship between the above two PWM techniques with various amplitude and frequency modulation indices to ensure the performance of FTMLI. A suitable comparative study was carried out to verify the PWM techniques based on the inverter output voltage, total harmonic distortion, switching stress, and filter size. The analytical conclusions are supported by the simulation results and their experimental validation.

An artificial neural network based approach for harmonic component prediction in a distribution line

With the increasing use of nonlinear devices in both generation and consumption of power, it is essential that we develop accurate and quick control for active filters to suppress harmonics. Time delays between input and output are catastrophic for such filters which rely on real-time operation. Artificial Neural Networks (ANNs) are capable of modeling complex nonlinear systems through adjustments in their learned parameters. Once properly trained, they can produce highly accurate predictions at an instantaneous time frame. Leveraging these qualities, various complex control systems may be replaced or aided by neural networks to provide quick and precise responses. This paper proposes an ANN-based approach for the prediction of individual harmonic components using minimal inputs. By extracting and analyzing the nature of harmonic component magnitudes obtained from the survey of a particular area through real-time measurements, a sequential pattern in their occurrence is observed. Various neural network architectures are trained using the collected data and their performances are evaluated. The best-performing model, whose losses are minimal, is then used to observe the harmonic cancellation for multiple unseen cases through a simplified simulation in hardware-in-the-loop. These neural network structures, which produce instantaneous and accurate outputs, are effective in harmonic filtering.

Dynamic Harmonic Distortion Analysis and Mitigation Strategies for DC Third Rail Systems

Harmonic distortions in DC third rail systems can cause overheating of electric motors and transformers. Single-tuned filters and shunt active harmonic filters (SAHFs) are often used to mitigate the harmonic distortions. However, there is a lack of studies on the effects of train dynamics on harmonic distortions. This paper aims to investigate the influence of dynamic train behaviors for a DC third rail system and provide recommendations for the design of single-tuned filters and SAHFs to mitigate the harmonic distortions. The traction power supply system of a DC third rail system in Malaysia is modeled using ETAP-eTraX and MATLAB-Simulink software for the investigation. The ETAP-eTraX software is used to accurately compute the dynamic behavior of the train, while MATLAB-Simulink allows for the assessment of the impact of train behavior on the rail track, as well as the harmonic effect of the railway power network on the train. The findings showed that the SAHF exhibits strong adaptability and superior filtering performance compared to the single-tuned filter in addressing dynamic harmonic distortion in traction power supply systems. This study emphasizes the significance of incorporating harmonic mitigation devices, particularly for managing dynamic harmonic distortion based on actual train consumption patterns.

Harmonic resonance evaluation and suppression of railway power conditioner-network-train coupling system

The coupling of railway power conditioner (RPC), network, and train will change the impedance characteristics of the existing traction power supply systems, which will lead to the unclear law of high-frequency harmonic resonance. This paper aims to study the resonance mechanism of the RPC-network train coupling system, and then solve the resonance problem of the existing traction power supply system from the perspective of reshaping the high-frequency impedance of the system. Firstly, the RPC-network-train coupling system’s dynamic node admittance matrix is established. After that, a comprehensive resonance evaluation method is proposed to obtain the resonance impact factors (RIFs) of multiple virtual impedances in the control strategy and the filtering parameters, which can realize the comparison and selection of five existing impedance reshaping strategies. To ensure the safe and stable operation of the RPC-network-train coupling system, a multi-objective sorting optimization strategy (MOSOS) considering resonance suppression, harmonics filtering, filter cost, and control system stability is proposed for the RPC based on the RIFs. Finally, the effectiveness of the proposed method is verified by the simulation result in MATLAB/Simulink and the experiment result in the StarSim hardware-in-the-loop (HIL) platform respectively.

Analysis, design, and optimization based on genetic algorithms of a highly efficient dual-band rectenna system for radiofrequency energy-harvesting applications

This paper gives an enhanced Rectenna design that operates at dual-band [2.45 and 5.8] GHz in the ISM (Industrial, Scientific, and Medical) band and is printed on an FR4-Epoxy substrate. This Rectenna design includes two proposed sub-designs for the receiving antenna and rectifier circuit based on the microstrip technology. The first sub-design concerns the microstrip patch antenna (MPA) described by its radiating element as a pentagonal, its ground being affected by a defective ground structure technique, and its polarization manner as circular polarization. This MPA design is analyzed, designed, optimized using genetic algorithms (GAs), simulated under CST MWS (i.e., computer simulation technology microwave studio), and confirmed by another software named HFSS (high-frequency structure simulator). The second sub-design concerns the microstrip rectifier circuit (MRC) that contains an input matching network based on a coupled-line impedance transformer strategy to achieve good adaptation between MPA and MRC, voltage doubler converter using an SMS7630 Schottky diode thanks to its high sensitivity, microstrip interdigital capacitor to mitigate the intrinsic losses due to the lumped elements, harmonic rejection filter based on a stepped-impedance low-pass filter to reject the unwanted harmonics generated by the non-linear behavior of SMS7630, and the resistive load that models the consumption of the system to be fed. This MRC is analyzed, designed, optimized using GAs, and simulated under ADS (Advanced Design System). The effectiveness of the proposed MPA is proven in terms of gain equals 3.06 dBi and 4.683 dBi at 2.45 GHz and 5.8 GHz respectively, and efficiency equals 95.13 % and 96.552 % at 2.45 GHz and 5.8 GHz respectively. The proposed MRC is effective in terms of efficiency at a lower input power value of about 97.18 % and 67.93 % at 2.45 GHz and 5.8 GHz respectively.

On design of preprocessing and postprocessing in cascaded-resonator-based harmonic analyzers and filter banks

The cascaded-resonator (CR)-based filter structure provides high attenuation in the stopbands thanks to the serially coupled resonators, which is an advantage in many applications of harmonic analyses and/or filtering. In addition to that, it has good properties provided by its parallel structure. On the other side, there are applications which besides the high stopband attenuation need wider (or even flat-top) passbands, lower group delays, etc. These performances can be modified/improved by preprocessing and postprocessing through reshaping of the primary CR-based filter bank frequency responses. The numerical complexity is also an important aspect where infinite impulse response (IIR) filters provide implementation with a smaller number of numerical operations, but involving nonlinearity of the phase responses and stability control issue. Although most of these issues have been discussed in the previous papers dealing with the design of the CR-based harmonic filtering and/or filter banks, the aim of this paper is to highlight them all together. In addition, some improvements of the previously described design techniques are suggested too.

Method for determining the harmonic contribution of consumer installations based on the application of passive filters

AbstractThe paper presents a new method for estimating the contribution of distortion sources based on the application of passive harmonic filters. The method does not require the measurement of harmonic network impedance and is based on the measurement of harmonic currents of the grid, consumers and passive harmonic filters. Evaluation of the consumer contribution using a passive harmonic filter is necessary to select the parameters and connection points for harmonic reduction devices. A feature of the method is the correct determination of share contributions, regardless of background harmonic distortions. Based on this method, a single consumer can evaluate both the harmonic contributions of its own loads, even in the presence of background distortions, and the harmonic voltage distortions in the case of installing harmonic reduction devices. The research results are confirmed in laboratory conditions with various combinations of electrical loads connected both at the grid side and at the consumer side. For such conditions, the proposed method was compared with existing methods, among which are methods based on the measurement of harmonic voltage vectors, harmonic current vectors and active harmonic power. The application of the developed method was demonstrated using the example of a gas production field.

A 46% PAE, 2.4-GHz Two-Stage Class E Power Amplifier Utilizing CMOS 0.13-µm Technology

A wireless device with a long battery life and great sensitivity becomes difficult to develop since there is a huge demand for low-power, low-cost wireless gadgets. The power amplifier (PA) is the most crucial part of radio frequency (RF) transceivers because of its massive power consumption. Consequently, in order to minimize power loss, a very effective and low-power consumption PA is needed. In this paper, high efficiency two-stage CMOS PA designed in 0.13-μm process for 2.4 GHz IoT transmitter applications is presented. The driver stage and power stage are the two stages that make up the two-stage topology of the proposed CMOS PA. To attain high efficiency and great power gain, a class E PA is used at the power stage. The LC matching network at the output is used for harmonic rejection filter at 2.4 GHz with an additional parallel capacitor helps for better harmonic rejection. In addition, a layout has been successfully designed and optimized. All the components in the proposed PA are designed on-chip. The pre-layout and post-layout simulations have been conducted to verify the proposed PA's performance. The pre-layout simulation of the proposed PA can deliver 19.19 dBm output power and 45.2% PAE at 2.0 V power supply into a 50-Ω load. On the other hand, the proposed PA produced an output power of 17.33 dBm and 46% PAE, according to the results of the post-layout simulation with a similar power supply of 2.0 V. The chip area for the proposed layout design is 1.05 mm2.

Novel hybrid arithmetic optimization algorithm-recursive least square approach for power system harmonic estimation

Abstract Accurate harmonic estimation is essential for effective power quality assessment, designing appropriate harmonic filters, and ensuring the reliable operation of electrical equipment. This article proposes a novel hybrid harmonic estimation technique combining recursive least square (RLS) and arithmetic optimization algorithm (AOA) for accurate estimation of harmonics, inter-harmonics and sub-harmonics. AOA is a new meta-heuristic method based on distribution behaviour of main arithmetic operators such as addition, subtraction, multiplication and division. RLS is used for estimation of amplitude of harmonics, whereas phase is estimated by AOA. The performance of AOA–RLS is investigated in detail for estimation of power system signals using two set of test signals buried with noise. The proposed AOA–RLS is proved to be efficient for estimating both phase and amplitude parameters under different signal to noise ratio (SNR) conditions with an estimation of error of E−3. The efficacy of AOA–RLS technique is demonstrated by comparing with competitive existing techniques. The performance of AOA–RLS also verified in experimental studies.

Designed harmonic step filter automatic control system to improve power quality and electric efficiency

Designed harmonic step filter automatic control system to improve power quality and electric efficiency

Harmonics management and hosting capacity enhancement: Optimal double-resistor damped double-tuned power filter with artificial hummingbird optimization.

This paper introduces a novel and improved double-resistor damped double-tuned passive power filter (DR-DDTF), designed using multi-objective optimization algorithms to mitigate harmonics and increase the hosting capacity of distribution systems with distributed energy resources. Although four different topologies of single-resistor damped double-tuned filters (DDTFs) have been studied before in the literature, the effectiveness of two different DR-DDTF configurations has not been examined. This work redresses this gap by demonstrating that via comprehensive simulations on two power systems, DR-DDTF provides better harmonic suppression and resonance mitigation than single-resistor alternatives. When it comes to optimizing the DR-DDTF for maximum hosting capacity and minimum system active power losses, the multi-objective artificial hummingbird outperformed six other algorithms in the benchmark. To allow for higher penetration of distributed generation without requiring grid upgrades, this newly developed harmonic mitigation filter provides a good alternative.

Power quality improvement of three-phase electrical systems using active-passive hybrid harmonic filter

An overreliance on nonlinear load can result in electric current harmonics, which will ultimately result in a decrease in the quality of the electrical power. If a malfunction arises as a consequence of the internal integration of a power system in any of the internal networks, it will have an adverse effect on the overall operation of the power system. Because of this issue, there is a requirement for harmonic filters, which can minimize the levels of harmonics by referencing the IEEE-519 standards for enhancing power quality. This research offers an active-passive hybrid harmonic power filter to eliminate harmonic pollution in three-phase electrical systems. A MATLAB simulation and laboratory experiment proceeded for 240 Vac with nonlinear loads that represent by uncontrolled rectifier and series RLC load, and selected results were presented to verify the performance of the active-passive harmonic filter component. Upon completion of this research, an analysis of the conditions of a three-phase electrical system will be possible under four distinct circumstances: in the absence of a filter, with an active filter, with a passive filter, and with a hybrid filter. Furthermore, this model performs a comparative analysis of the percentage reduction in THD value achieved by the filter compared to the previous researcher. The result analysis reveals the proposed filter's good performance in eliminating harmonic pollution to 58.63 %, thereby significantly improving power quality. The findings presented in this study contribute to the ongoing efforts to ensure the reliable and efficient operation of modern power systems.

Sensorless Control of Induction Motor Based on Rotors Slot Harmonics and Digital Adaptive Filters

Sensorless Control of Induction Motor Based on Rotors Slot Harmonics and Digital Adaptive Filters

Review of Multilevel Level Inverter Using Different Topologies

This paper provides a concise overview of various multilevel inverter (mli) topologies. The conventional two-level voltage source inverter (vsi) necessitates a filter to generate sinusoidal output waveforms, which can be challenging at high frequencies due to switching losses. To address this issue, multilevel inverters offer lower switching frequencies and reduced total harmonic distortion (thd), eliminating the need for filters and large transformers. Moreover, a few advantages of mli inverters are reduced switching losses, better performance at high switching frequencies, and higher power quality (almost pure sinusoidal). Nevertheless, adding to the complexity of the system is the requirement for each switch to have its own gate driver in order to perform mli. Thus, it's imperative to decrease the mli's number of switches. In order to reduce the number of switches needed, this paper reviews some of the various current topologies. Applications such as voltage regulation, var compensation, harmonic filtering in power systems, and user interface for renewable energy have led to the development of cascaded h-bridge multilevel inverters. For solar applications, a modified cascaded h-bridge multilevel inverter (mli) is used. Cascaded h-bridge topology multilevel inverter will aid in reducing the number of switches. Comparing this concept to other multilevel inverters, the switching complexity is reduced.

Determination of Optimal Locations and Parameters of Passive Harmonic Filters in Unbalanced Systems Using the Multiobjective Genetic Algorithm

This paper discusses the problem of optimal placement and sizing of passive harmonic filters to mitigate harmonics in unbalanced distribution systems. The problem is formulated as a nonlinear multiobjective optimisation problem and solved using the multiobjective genetic algorithm. The performance of the proposed algorithm is tested on unbalanced IEEE 13- and 37-bus three-phase systems. The optimal solutions are obtained based on the following objective functions: 1) minimisation of total harmonic distortion in voltage, 2) minimisation of costs of filters, 3) minimisation of voltage unbalances, and 4) a simultaneous minimisation of total harmonic distortion in voltage, costs of filters, and voltage unbalances. Finally, an analysis of the influence of uncertainties of load powers and changes in system frequency and filter parameters on filter efficiency was performed.

Application of active and passive filter-compensating devices to reduce the negative effects of harmonic distortions

Subject of research: processes occurring in electrical networks with induction heating installations. Purpose of research: filter compensators. Object of research: study of design features of active and passive harmonic filters. Methods of research: in the process of performing research, scientific and technical generalization of literary sources according to the initial prerequisites for research, methods of probability theory and mathematical statistics were used. Experimental studies were carried out by a complex method using the Resurs-PKE device. Main results of research: on the basis of conducted researches it is shown that filter-compensating devices can effectively reduce the negative impact of harmonic distortions.