Harmonic Suppression Research Articles

Simulation and implementation of a harmonics suppression technique for a single-phase full-bridge converters

ABSTRACT This paper presents a harmonic suppression technique for a single-phase full-bridge converter, and the mathematical principles underlying a modified PWM technique are discussed. To verify the effectiveness of the proposed technique, voltage and current sensor circuits in a single-phase full-bridge converter connected to a digital signal processor controller with an analog-to-digital converter were analyzed experimentally. The output voltage harmonics of the converter were examined, and the frequency spectra of the output voltage were analyzed. Furthermore, a digital control system with a TMS320F2808 digital signal microcontroller was realized. The experimental results verified the effectiveness of the proposed technique in suppressing low-frequency harmonic in a prototype of a converter.

Research on grid-connected harmonic current suppression of three-phase four-wire energy storage inverters

Research on grid-connected harmonic current suppression of three-phase four-wire energy storage inverters

ACTUAL DIRECTIONS FOR THE IMPROVEMENT OF STATE BUILDING STANDARDS FOR THE DESIGN OF NEW AND RECONSTRUCTION OF EXISTING EDUCATIONAL INSTITUTIONS

The article provides an analysis of state building regulations that apply to the design of new and reconstruction of existing buildings of educational institutions, from the point of view of compliance with modern international requirements. The expediency of improving the state building regulations by supplementing them with the current requirements of European safety standards and standardizing the physical factors of the production environment has been demonstrated. It is shown that the requirements of individual national sanitary norms and rules, which are integral components of the considered state building norms, require coordination. Quantitative maximum allowable values of electromagnetic fields of individual frequency divisions, as well as approaches to determining integral indicators of electromagnetic load on the environment, require coordination. Organization of grounding and suppression of industrial frequency harmonics and interharmonics of electrical consumers with non-linear volt-ampere characteristics must be carried out at the stage of designing power supply systems for civilian buildings by improving the regulatory framework. Sanitary regulations and rules referred to by state building regulations must meet the requirements for the limit levels of infrasound and aeroionization of air, which should be implemented in view of the requirements of current European regulations.

Selective Virtual Synthetic Vector Embedding for Full-Range Current Harmonic Suppression of the DC Collector

With the rapid development of rene wable energy (e.g., wind and photovoltaic energy) and energy storage, the dc collector has become an effective conversion link of distributed energy access to medium-voltage power distribution grids. However, considering the inconsistency of dc voltage and the duty cycle of each submodule, the traditional carrier phase-shifting modulation is difficult to achieve the excellent harmonic characteristic in the dc collector, thereby introducing difficulties in the design of passive filters. To solve this problem, this article proposes a selective virtual synthetic vector embedding algorithm to realize full-range current harmonic suppression in the dc collector system. In this scheme, the switching voltage vectors outputted by each submodule are sorted, and the voltage vectors are selectively extracted and synthesized to calculate the embedded virtual voltage vector. Afterward, the voltage vector of each submodule is rotated and calculated online from the perspective of space geometry, and the optimal carrier phase combination in variable-angle carrier phase-shift modulation is obtained. Finally, the experimental results show that the proposed control algorithm can not only be used in the dc collector with any number of modules but also achieve fast and effective harmonic suppression in the whole operating range.

A Novel Filter With High Harmonics Attenuation and Small Dimension for Grid-Connected Inverter

Passive power filters are indispensable for grid-connected inverters (GCIs) to eliminate current harmonics. However, typical filters require large inductance, which not only increases the filter dimension and costs but also leads to slower current response and a high voltage drop across the filter. This article proposes a novel filter called LCTCL filter, which effectively attenuates harmonics with small inductance. In addition, this article presents a controller synthesis to the GCI with LCTCL filter without an additional resistor. We demonstrate the effectiveness of the proposed LCTCL filter through comparative analysis with typical filters via simulations and experiments. We clarify that the proposed LCTCL filter has excellent features in terms of filter dimension, frequency characteristics, robustness for parameter variations, harmonic suppression, and total harmonic distortion.

A Wideband Balun Filter Based on Folded Ring Slotline Resonator and Dual-Feedback Stubs With >17.8 f 0 Stopband Rejection

This brief proposes a wideband balun filter with ultrawide stopband utilizing a shunt slotline coupled with a folded ring slotline resonator (FRSR) and dual-feedback stubs (DFS). Utilizing the FRSR, there are four transmission poles (TPs) within the passband and ten transmission zeros (TZs) in the range of < 20 GHz generated, which contribute to large bandwidth, high selectivity, and >10-dB harmonic suppression. In addition, the two additional TZs generated by the DFS can improve the harmonic suppression to >18 dB. In the meantime, the folded slotline design effectively reduces the size of the proposed balun filter to 33.2% of the conventional round slotline ring. The fabricated balun filter demonstrates a 111% fractional bandwidth (FBW) centering around <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$f_{0}$ </tex-math></inline-formula> of 2.25 GHz, a measured stopband up to 40 GHz (17.8 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$f_{0}$ </tex-math></inline-formula> ) with a minimum rejection level of 18 dB, and a shape factor of 1.3. To the best of the authors’ knowledge, both the fractional bandwidth and stopband range achieved by the balun filter are among the best.

Flux-Weakening Controller Design of Dual Three-Phase PMSM Drive System With Copper Loss Minimization

The performance of flux-weakening controllers in the multiphase permanent magnets (PM) machines depends on the accurate fundamental voltage limit derivation, and the minimal copper loss design in the flux-weakening operation region has not been well discussed. In this article, the accurate fundamental voltage limit with considering harmonic current suppression is derived at first. Then, two control concepts are addressed, and the corresponding flux-weakening control strategies are designed with the gradient descent method. In the first control strategy, both the fundamental and harmonic voltage vectors are feasible, resulting in the larger amplitude of the phase currents. The second control strategy obtains higher bus voltage utilization by an additional transition stage. At the same time, the harmonic currents cannot be further suppressed in the flux-weakening operation region. Third, the copper loss per electrical cycle is calculated, and a switching scheme is designed to obtain lower copper loss in the flux-weakening operation region. Finally, both strategies are successfully implemented in a dual three-phase PMSM. Moreover, the proposed switching scheme obtains minimal copper loss in the whole flux-weakening operation region.

Online Inductance Identification and FPGA-Based Real-Time Digital Control Design for APF

The harmonic suppression performance of active power filter (APF) under model predictive current control is obviously reduced, when the parameter exists a mismatch between the actual value in system and the nominal value adopted in the control. To suppress the influence of parameter mismatching, a model predictive control based on parameter identification with forgetting factor recursive least square (FFRLS) method is proposed for APF. The digital processing procedure of the FFRLS-based APF controller is detailed analyzed and designed. The identification error of inductance between identification value and the actual value is less to 6%, and the total harmonic distortion of grid current is significantly improved, especially a lower value of actual inductance. Simulation and experimental results show that the proposed method can not only effectively eliminate the influence of parameter mismatch on the control, but also result in better steady-state performance while retaining fast dynamic response.

A Dual-Band Branch-Line Coupler with Ultra-Wideband Harmonic Suppression

A dual-band branch-line coupler with ultra-wideband harmonic suppression is proposed in this paper. The conventional quarter-wavelength transmission lines are replaced with π-shaped lines to achieve a dual band. In addition, ultra-wideband harmonic suppression is obtained by the frequency-selecting coupling structure (FSCS) providing three transmission zeros. The two operating frequencies are 0.9 GHz and 2.0 GHz, and the corresponding -10 dB bandwidth at 0.9 GHz and 2.0 GHz is 18.9% and 10.5%, respectively. A wide harmonic suppression band is generated from 3.7 GHz to 8.3 GHz. The simulation and measurement results are in good agreement.

Design and analysis of novel DGS-loaded low-pass filter with wide stopband

Abstract This article deals with design and development of a novel 7th order low-pass filter with defected ground structures for S-band applications. The proposed LPF structure was comprised of dumbbell shaped interdigital defected ground structures and open stubs as series inductor and shunt capacitor in the pass band. In addition, an equivalent circuit model was derived and optimized to achieve a 3-dB cut off frequency about 4 GHz with a reflection coefficient of better than −20 dB. Moreover, proposed low-pass filter was manufactured on a Rogers RO4003C substrate with a dielectric constant of 3.38, the dissipation factor of 0.0027. The developed LPF has a very flat pass-band with a transmission coefficient less than −0.5 dB and the measured transmission coefficient better than −18 dB in the passband (DC-3.6 GHz). Meanwhile, the prototype has a 20 dB harmonic suppression level in the frequency range from 5.54 GHz up to 43.5 GHz. Furthermore, the measured peak to peak group delay variation was less than 170 ps in the passband. The proposed filter has a very compact size of 195.3 mm2.

Lightweight SAR: A Two-Bit Strategy

By benefiting from one-bit sampling, the system deployment of synthetic aperture radar (SAR) can be greatly simplified. However, it usually requires a high oversampling rate to avoid the apparent degradation in imagery, which counteracts the storage-saving advantages. In this paper, a two-bit lightweight SAR imaging strategy is proposed to take the advantage of one-bit quantization in simplification but get rid of the requirement of sampling at a high rate. Specifically, based on one-bit quantization, an extra bit after an appropriate phase shifting is introduced to suppress the harmonics resulting from the nonlinear effect of quantization. In this way, the awkward nonlinearity in conventional one-bit schemes can be tackled by the nonlinearity generated with the newly introduced bit. Hence, this improves the imaging quality. In addition, the proposed method does not rely on fast sampling. The harmonic suppression effect is retained under low-sampling-rate conditions. Therefore, the amount of data acquired will decrease dramatically. This will benefit the whole process of imaging and, consequently, lighten the system burden and cost. The theoretical analysis and experimental results showcase the superiority of the proposed method.

Traction transformer integrated LCL filtering method for high-frequency harmonic and resonance suppression in AC train

Converters in AC-DC-AC traction drive system introduce a wide range of high-frequency harmonics. When the high-frequency harmonics contain contents at around the inherent resonance frequency of the traction power supply system, it will cause harmonic resonance in the traction grid. The LCL-type single phase line-side converter is widely adopted to prevent the high-frequency harmonics from entering the traction grid. However, additional four inductors and four capacitors are needed to form the filtering system, which increases the occupied onboard space. In this paper, a traction transformer integrated LCL filtering method is proposed to achieve high-frequency harmonic and resonance suppression and, at the same time, reduce the space occupied by the LCL filter. The equivalent circuit of the traction transformer integrated LCL filtering system is modeled and the mechanism of harmonic and resonance suppression is analyzed. Then, the required equivalent impedances of the traction transformer, the filtering capacitor, and the corresponding controller of line-side converter are designed. Finally, the parameter design of the traction transformer prototype is verified by finite element simulation. And the grid-train system with the traditional L filter, LCL filter, and the proposed traction transformer integrated LCL filter are simulated by real-time field-circuit coupling simulation, which verifies the good filtering effect of the proposed method.

A novel premium power supply scheme against harmonic suppression for non-linear park

• A method for harmonic-suppression needs identification is proposed to guide non-linear customers to actively participate in harmonic mitigation. • The novel premium power supply scheme against harmonic suppression for non-linear park can effectively solve the harmonic problems with the situations that all the participants are satisfied. • A DEA-based method is proposed to reasonably realize allocation of the scheme costs. • The proposed scheme provides the possibility for the power grid and customers to jointly control harmonic problems. With the continuous development of power grids, the power electronization rates of power systems are increasing, and problems caused by harmonic pollution are becoming major concerns. Generally, harmonic problems result from the electric utility and non-linear customers, thus the mutual collaboration of both parties is crucial to addressing these problems. However, due to the indeterminate needs of non-linear customers for harmonic suppression and high investment pressure for harmonic suppression, customers are reluctant to participate in mitigation, which makes harmonic suppression appear prevarication. As a result, harmonic suppression cannot be carried out smoothly. To solve this problem, a novel premium power supply scheme against harmonic suppression for non-linear park is proposed. Firstly, this paper presents a method for harmonic-suppression needs identification based on super-efficiency interval model to attract customers to participate in harmonic suppression. Secondly, a premium power supply scheme is proposed, which consists of harmonic-suppression needs identification, suppression strategy design and scheme cost allocation. Furthermore, to reasonably allocate the scheme costs among each participant, this paper proposes a data envelopment analysis (DEA) based method considering the influence of both harmonic contribution and harmonic-suppression needs. Finally, case studies are used to verify the effectiveness and correctness of the proposed methods and the scheme.

Stability Analysis of Three-Port Cascaded Inverter System With Second Harmonic Current Suppression

Considering the secondary power fluctuation, usually, it is necessary to cascade the second harmonic current suppression circuit (SHCSC) in the front of the single-phase inverter. However, it may result in the cascaded system being unstable, so far, the issue has received little attention yet. In this article, the active negative capacitor (ANC) is employed to eliminate the second harmonic current (SHC) and the Middlebrook criterion is employed in the proposed cascaded DC-AC system with SHCHC. The small-signal model of each subsystem is established initially, which is more accurate than the conventional model. Correspondingly, the output/input impedance and necessary stability conditions are obtained. Based on the stability condition, the influence that comes from control and circuit parameters on the impedance of each subsystem is revealed and the parameter constraints for input filter inductor and load are given, which guides to design of a stable system. Last, the filter inductor is taken as the freedom to improve the system stability considering different load conditions. Finally, a 500W prototype is built, and simulation results are in good agreement with experimental results. The stability analysis method could be extended to any other three ports system.

Simulation and Realization of Multi-Frequency Signals Based on Harmonic Suppression

Simulation and Realization of Multi-Frequency Signals Based on Harmonic Suppression

Kernel-Based Impulse Response Estimation Using Perturbation Signals With Harmonic Suppression

This letter proposes the use of perturbation signals with harmonic suppression for kernel-based (KB) impulse response estimation of the underlying linear dynamics of a system corrupted by nonlinear distortion. In particular, signals with harmonic multiples of two suppressed can eliminate the effects of even order nonlinear distortion on the linear estimate, whereas signals with harmonic multiples of two and three suppressed can further reduce the effects of odd order nonlinear distortion, significantly improving the estimation accuracy. It is shown that the KB formulation effectively avoids the lack of persistency of excitation problem encountered in the classical least squares when such signals are applied, thus allowing a shorter experimentation time. An application on an electronic nose achieves a drastic reduction in the output mean square error by a factor of 9.2 through the utilization of a signal with harmonic suppression.

Ultralow-Phase-Noise Microstrip Oscillator Based on Quasi-Bandpass Frequency Selection Network With Multiple Transmission Zeros

This article proposes a microstrip feedback-type oscillator incorporating a novel quasi-bandpass frequency selection network (FSN) for low phase noise (PN) operation. Through introducing direct source/load coupling between two coupled quarter-wavelength resonators, the FSN can theoretically realize a canonical second-order general Chebyshev bandpass response with two transmission zeros. Furthermore, the feedlines with short-circuited ends are specifically designed to generate more transmission zeros. Accordingly, this FSN is featured by quasi- bandpass response with multiple transmission zeros, so that high group delay and good out-of-band performance are achieved. Such feature plays an important role in the oscillator performance. As demonstration, one oscillator example was fabricated and measured. Its operating frequency is 1.98 GHz, the PN is −129.85 dBc/Hz at 100 kHz, the output power is 9.61 dBm, and the second harmonic suppression (SHS) reaches 48.21 dBc. All these indexes outperform those of all the other oscillators, and our reported PN is the lowest one in S-band up to now.

Synthesis Design of Wideband Bandpass Filter With High Selectivity and Harmonic Suppression

A novel wideband quasi-Chebyshev bandpass filter (BPF) with steep skirt selectivity and extended upper stopband is presented. It is comprised of two microstrip-to-microstrip vertical transitions with nonuniform slotline sections, which cascaded directly by a nonuniform microstrip connecting line. In terms of odd-/even-mode analysis, the in-band six poles which make up the wideband bandwidth can be explicitly derived. Moreover, the Chebyshev equal-ripple filtering responses with prescribed specifications can be conveniently achieved in desired passband by adopting synthesis theory. In order to suppress the second and third spurious harmonics, a modified circuit model based on synthesis method is further proposed. Two additional transmission zeros (TZs) TZ3, TZ4 can be generated at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3f_{0}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5f_{0}$ </tex-math></inline-formula> respectively by adjusting impedance ratio of slotline stubs properly under the condition of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\theta _{\mathrm {s1}} = \theta /4$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\theta _{\mathrm {s2}} = \theta /2$ </tex-math></inline-formula> , which widen the upper stopband bandwidth greatly and enhance harmonic rejection level effectively. Meanwhile, combing with the inherent periodic finite-frequency TZ5, TZ6 and TZ7, the upper stopband could be extended to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$6.22f_{0}$ </tex-math></inline-formula> with rejection level better than 14.6 dB. Besides, a pair of finite-frequency TZ1 and TZ2 caused by source-load coupling occur at both sides of passband to sharpen the cutoff slope of skirts remarkably. For verification, a prototype is fabricated and measured, the experimental results agree well with the theoretical predictions, which verify the validity of proposed method.

Resilient Control Algorithm for Wind-Hydro Based Distributed Generation System with Grid Synchronization Capability

A microgrid is key to an efficient and resilient power grid operation. Thus, in this paper, a robust control scheme is implemented namely a modified frequency locked loop (MFLL), proficient in eliminating the voltage and current fluctuations because of phase/frequency variation. Therefore, enhancing the consistency of the supply across local nonlinear load through a smooth transition from utility-interactive mode to islanded mode. It also achieves accelerated convergence and reduced steady-state error. MFLL is an easy control technique, with only one interfacing voltage source converter, which delivers a stable supply to critical loads during different operating modes. The implemented system has the main advantage of the capability of power-sharing between distributed generation (DG) systems while regulating the voltage at the DC link. It also provides power quality improvement through harmonics suppression; voltage regulation during contingencies like unbalance in load and compensation in reactive power at the common coupling point following the prerequisite of the system. Performance through the implemented control algorithm is brought within MATLAB 15b/Simulink platform and validated through experimental results. Performances are compared with already reported control strategies. Thus, simulated results comparison with existing work presents the competence of the implemented control strategy under dynamic conditions.

An approach to harmonic optimization for 25KVA auxiliary converter used in indian railway

As the Indian railway network expands, the demand for reliable and efficient power systems, especially auxiliary converters supporting various on-board systems, grows. By reducing power losses and fuel consumption, it is more crucial to design an energy-efficient and economic auxiliary converter for the railway system. This is partially accomplished by using a 25KVA auxiliary (Aux.) converter, which can accept input electrical energy from a 110V DC battery at Self-Generation (SG) coaches. Biogeography Based Optimization (BBO) method of harmonic elimination for a 25KVA converter is described in this study. The paper explores the 120-degree mode of conduction and compares the existing technique with a proposed 7-switching selective odd harmonic removal method. Results from Matlab simulations demonstrate the effectiveness of the BBO technique in reducing Total Harmonic Distortion (THD). The output voltage waveforms with and without BBO are compared, showcasing a significant improvement in harmonic suppression. The paper concludes by emphasizing the practical implementation of the optimized switching angles using an ATmega2560R3 microcontroller. The online application of stored switching angles on the microcontroller is calculated offline.