Harmonic Suppression Research Articles

General rotationally symmetric coupled feeding structure and its application to single- and dual-band balanced filters

This paper proposes a new general rotationally symmetric coupled feeding structure and its applications to the design of single- and dual-band balanced filters for high common-mode (CM) suppression. The balanced feeder consists of two coupling lines coupled with a ring resonator, which can be either a uniform impedance ring resonator or a stepped impedance ring resonator. Under differential-mode (DM) excitation, the voltage distributions of the coupling-line and resonator are both rotationally even-symmetric and the total coupling coefficient adds up, which indicates that the proposed feeding structure can achieve DM transmission characteristic. Under CM excitation, their voltage distributions are rotationally even- and odd-symmetric, respectively, so the total coupling coefficient cancels out to zero and CM suppression property is achieved. For demonstration, four single- and dual-band balanced filters with wide range of CM and harmonic suppression are designed, fabricated, and measured, and the simulation and measured results match well.

A 22-mW 0.9-2-GHz mixer-first receiver 8-phase overlap-suppressed 1/4 duty cycle LO for harmonic rejection

This paper presents a mixer-first wideband receiver front-end designed to achieve high linearity and harmonic rejection while minimizing power consumption. The proposed RF front-end adopts LO overlap suppression technology and uses 25 % duty cycle LO for 8-phase operation. In addition, the passive mixer with implicit capacitive stacking provides passive gain to the useful signal and improves harmonic rejection. The total power consumption of this work is less than 22 mW, the majority of which is consumed by the baseband amplifier and buffer, making it superior to existing active harmonic suppression RF front-ends in terms of low power consumption. The receiver is designed in TSMC 65-nm technology with an active area of 0.44 mm2 and is suitable for various communication standards from 0.9 GHz to 2 GHz. Post-layout simulation results show that < −15 dB S11, 16.7-dBm OOB-IIP3@80 MHz, 3.7–6.7 dB DSB-NF, 46.4–49.5 dB total system voltage gain and HRR3 of 35.4–42 dB are achieved. No active components are required for harmonic recombination.

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.

A Novel Second Harmonic Voltage Suppression Control for PSFB Converter in Dual-Stage Single-Phase Rectifier

The inherent second harmonic power pulse in single-phase grid-connected rectifiers leads to a noticeable output voltage ripple and thus results in the degradation of the system. A novel second harmonic suppression control is introduced in this paper to address this issue. The key point of the proposed control lies in the real-time prediction of the phase-shifted full-bridge (PSFB) converter’s desired duty cycle through accurate PSFB converter modeling. By accurately predicting the ideal duty cycle, the proposed control facilitates a significant enhancement in the control loop’s gain specifically at the second harmonic frequency, thereby improving the overall system performance. To validate the theoretical analysis, a series of simulations and experiments were conducted. The results demonstrate the effectiveness of the proposed second harmonic suppression control in mitigating second harmonic output voltage ripple.

Research on harmonic suppression characteristics and control methods for low-frequency resonance suppressor

The problem of low-frequency harmonics and their resonance seriously threatens the safety of the fusion power supply system, and is one of the key issues that urgently need to be solved during high-power operation of fusion devices. The low-frequency resonance suppressor (LFRS) can compensate for the low frequency harmonic suppression effect of passive filter and active filter and the limitation of voltage and capacity, which is a new approach to solve the low frequency resonance problem of fusion power system. However, the performance of the LFRS is affected by the power grid parameters and the fundamental current circulation between the active filter and passive filter branches. The low frequency harmonic current and its resonance suppression characteristics are analyzed based on the multi-reference vector control strategy in this paper. On this foundation, a current double closed loop control method is proposed, which can ensure the safe and reliable operation of the LFRS system and the suppression effect of low frequency harmonic current. The correctness and effectiveness of the theoretical analysis are verified by RT-LAB Hardware-in-the-loop simulation.

A comprehensive review on recent trends and future prospects of PWM techniques for harmonic suppression in renewable energies based power converters

Research has concentrated on promoting the development of environmentally friendly energies since air pollution, energy crises, and global warming are main challenges in modern era. One effective way to reduce environmental damage is to use Renewable Energy Resources (RER). The prominence of RER is increasing due to escalating global energy challenges. Power converter development and application are closely associated to the deployment of RER. One major problem with these power converters is the presence of extremely high harmonic components in their output voltage. Various PWM techniques are employed to suppress harmonics and no singular PWM technique is universally applicable to all circumstances. Firstly, this review paper provides readers with in-depth explanation of the significance of harmonic suppression as well as presentation of several important PWM strategies. Then, the advantages and disadvantages are explored, and the methods are compared in terms of the number of harmonics suppressed by each PWM technique. Further, this review also discusses and describes harmonics suppression, PWM categorization, Single PWM, Multiple PWM, Sinusoidal PWM, Modified Sinusoidal PWM, SVPWM, Hysteresis PWM, Selective Harmonic Elimination PWM, and Multiple Carrier PWM, as well as their benefits and drawbacks. Tables with comparative assessment based on various parameters are provided for each PWM technique. Lastly, conclusion with a thorough presentation of future tendencies is provided.

A Master-Slave-Structure Position Observer for Multiharmonics Suppression in Sensorless PMSM Drives

Due to the influence of inverter nonlinearity and nonideal spatial flux, it inevitably exists the back electromotive force (BEMF) harmonics in permanent magnet synchronous motor (PMSM) drives, affecting the accuracy of model-based position-sensorless control. Although different schemes have been studied to suppress the BEMF harmonics, it is still challenging to alleviate the contradiction between harmonics suppression effect and structure complexity. To address this problem, a master-slave-structure position observer is proposed for multi-harmonics suppression in this paper. With the help of the master-slave structure, the fundamental frequency component of the BEMF is extracted as the output of the studied observer, realizing the separation from the harmonic components. The number of the integrators can be reduced by half with the complex-coefficient resonators instead of the real-coefficient resonators. Thus, the design degree of freedom is fully exploited to realize the desired frequency-domain characteristics of band-pass and specific frequency band-stop. The studied method is verified by the experiments on a 2.2-kW PMSM platform.

Study on Winding Design of Dual Three-Phase Electrical Machines for Circulating Current Harmonics and Vibration Suppression

The dual three-phase electrical machines (DTP-EMs) have significant advantages and application potential in large-power and high reliability electromagnetic drive system. Nevertheless, one of the main operating challenges of DTP-EMs is the significant high-frequency circulating current harmonics when supplied with voltage-source inverters (VSIs), which will bring unexpected vibration and loss. This paper provides a thorough study on the mutual magnetic coupling effect and design criterion of dual three-phase winding. First, the mathematical model of DTP-EMs is established. Then, the internal mechanism of mutual magnetic coupling and the relationship among the mutual leakage inductance in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$x$</tex-math></inline-formula> - <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$y$</tex-math></inline-formula> subspace, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\alpha$</tex-math></inline-formula> - <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\beta$</tex-math></inline-formula> subspace and stator leakage inductance is revealed. Furthermore, the winding design criterion for DTP-EMs considering high-frequency circulating current harmonics and vibration suppression is proposed. It is drawn that full pitch is required for DTP-EMs to minimize the high-frequency current harmonics and vibration. Finally, two prototypes of the DTP-EM are built and tested to validate the theoretical analysis. This paper provides an effective winding design guide of DTP-EMs for the high-frequency current harmonics suppression and can also be expand to other multi-phase machines.

Optimized MMC passive impedance shaping method for high frequency oscillation suppression

Recent years, there have been several high-frequency oscillation events in modular multilevel converter (MMC) based DC current projects. Considering the wideband oscillation characteristics of this issue, passive MMC impedance shaping methods are superior solutions for their advantages over the active methods in enhancing the broadband damping level. However, the optimization of parallel passive devices mainly focused on reactive power compensation and the suppression of characteristic harmonics generated by low-level inverters, which is not applicable to MMC systems. To address the optimization design problem of passive damping devices, this paper proposes an optimized design method for passive filters by analyzing the relationship between the passive damping device and the impedance shaping effect of the inverter. The proposed method reduces the capacity of the passive damping device while ensuring system stability margin. Finally, the effectiveness of the proposed passive impedance shaping strategy is verified through time-domain simulations considering changes in AC side operating conditions and power reduction operation of the MMC.

Critical Analysis of Active Filter for Harmonic Reduction under Varying Load

In this paper, we give the main focus on the proliferation of non-linear loads in power systems, the mitigation of harmonics has become a critical concern to ensure stable and efficient operation. This study presents an analysis of an advanced control active filter (ACAF) designed for harmonic reduction under varying load conditions. The ACAF is a sophisticated solution that employs advanced control algorithms to effectively suppress harmonics and maintain power quality. The research investigates the performance of the ACAF under varying load conditions, which represent real-world scenarios where power consumption fluctuates. A comprehensive analysis is conducted to evaluate the filter's ability to adapt and maintain harmonic suppression efficiency across different load profiles. The study considers various load scenarios, including steady-state operation, transient load changes, and dynamic load fluctuations. The findings of this research contribute to the understanding of advanced control active filters in practical power systems with non-linear loads and varying operating conditions. The analysis provides valuable insights into the design, optimization, and implementation of ACAFs for harmonic mitigation, ultimately improving power quality and system reliability in modern electrical networks. A classified list of 38 publications on this topic is also given for the quick reference.

A new technique for improving performance of conventional CRLH resonators using IDC/UISs with enhanced harmonic suppression in balanced dual-band BPFs

Abstract The design of balanced filters based on composite right/left hand (CRLH) structure is well developed. Among those, few designs exist which although they provide some good responses, suffer from narrow stopbands and interdependent passbands. This paper proposes a new technique for improving the characteristics of dual-band balanced bandpass filters (B-BPFs) based on planar CRLH. Using unequal inductive stubs (UISs) attached to the interdigital capacitor (IDC) unit cell, we were able to achieve outstanding harmonic suppression and passband controllability. This structure offers higher degrees of freedom compared to conventional designs and provides better control over the filter specifications. Mathematical modeling, analysis, simulation, fabrication, and performance measurement of the proposed technique in a dual-band B-BPF are also provided. Our work resulted in an independent and controllable dual-band B-BPF with ultra-wide upper differential-mode (DM) stopband of 5.9f 1 and common-mode (CM) suppression of 40.4 and 32.6 dB for the first and second bands, respectively.

Hybrid-paralleled power-factor-correction system for high-power equipment harmonic suppression

Hybrid-paralleled power-factor-correction system for high-power equipment harmonic suppression

Evaluation of Interval Type-2 Fuzzy Neural Super-Twisting Control Applied to Single-Phase Active Power Filters

This research introduces an improved control strategy for an active power filter (APF) system. It utilizes an adaptive super-twisting sliding mode control (STSMC) scheme. The proposed approach integrates an interval type-2 fuzzy neural network with a self-feedback recursive structure (IT2FNN-SFR) to enhance the overall performance of the APF system. The IT2FNN with STSMC proposed here consists of two components, with one being IT2FNN-SFR, which demonstrates robustness for uncertain systems and the ability to utilize historical information. The IT2FNN-SFR estimator is used to approximate the unknown nonlinear function within the APF. Simultaneously, the STSMC component is integrated to reduce system chattering, improving control precision and overall system performance. STSMC combines the robustness and simplicity of traditional sliding mode control, effectively addressing the chattering problem. To mitigate inaccuracies and complexities associated with manual parameter setting, an adaptive law of sliding mode gain is formulated to achieve optimal gain solutions. This adaptive law is designed within the STSMC framework, facilitating parameter optimization. Experimental validation is conducted to verify the harmonic suppression capability of the control strategy. The THD corresponding to the designed control algorithm is 4.16%, which is improved by 1.24% and 0.55% compared to ASMC and STSMC, respectively, which is below the international standard requirement of 5%. Similarly, the designed controller also demonstrates advantages in dynamic performance: when the load decreases, it is 4.72%, outperforming ASMC and STSMC by 1.15% and 0.38%, respectively; when the load increases, it is 3.87%, surpassing ASMC and STSMC by 1.07% and 0.36%, respectively.

Low phase noise anti-interference differential oscillator based on balanced bandpass filter with common-mode reflectionless characteristic

In this paper, a low phase noise anti-interference differential oscillator is proposed. The balanced bandpass filter with common-mode reflectionless characteristic is proposed and adopted in the differential oscillator to simultaneously achieve high group delay peak and common-mode interference noise absorption. For demonstration, the proposed differential oscillator is designed, simulated, manufactured and measured. It demonstrates that the proposed differential oscillator has a high output power of 6.67 dBm at the center oscillating frequency of 2.48 GHz, excellent second harmonic suppression of 46.01 dB, low phase noise of − 119.96 dBc/Hz at 100 kHz offset. The verification of the anti-interference function is performed with a differential mixer and the results show that the proposed differential oscillator can absorb external common-mode interference and effectively ensure the stable output of intermediate frequency signals.

Catalyzing satellite communication: A 20W Ku-Band RF front-end power amplifier design and deployment.

This paper presents a groundbreaking Ku-band 20W RF front-end power amplifier (PA), designed to address numerous challenges encountered by satellite communication systems, including those pertaining to stability, linearity, cost, and size. The manuscript commences with an exhaustive discussion of system design and operational principles, emphasizing the intricacies of low-noise amplification, and incorporating key considerations such as noise factors, stability analysis, gain, and gain flatness. Subsequently, an in-depth study is conducted on various components of the RF chain, including the pre-amplification module, driver-amplification module, and final-stage amplification module. The holistic design extends to the inclusion of the display and control unit, featuring the power-control module, monitoring module, and overall layout design of the PA. It is meticulously tailored to meet the specific demands of satellite communication. Following this, a thorough exploration of electromagnetic simulation and measurement results ensues, providing validation for the precision and reliability of the proposed design. Finally, the feasibility of that design is substantiated through systematic system design, prototype production, and exhaustive experimental testing. It is noteworthy that, in the space-simulation environmental test, emphasis is placed on the excellent performance of the Star Ku-band PA within the 13.75GHz to 14.5GHz frequency range. Detailed power scan measurements reveal a P1dB of 43dBm, maintaining output power flatness < ± 0.5dBm across the entire frequency and temperature spectrum. Third-order intermodulation scan measurements indicate a third-order intermodulation of ≤ -23dBc. Detailed results of power monitoring demonstrate a range from +18dBm to +54dBm. Scans of spurious suppression and harmonic suppression, meanwhile, show that the PA evinces spurious suppression ≤ -65dBc and harmonic suppression ≤ -60dBc. Rigorous phase-scan measurements exhibit a phase-shift adjustment range of 0° to 360°, with a step of 5.625°, and a phase-shift accuracy of 0.5dB. Detailed data from gain-scan measurements show a gain-adjustment range of 0dB to 30dB, with a gain flatness of ± 0.5dB. Attenuation error is ≤ 1%. These test parameters perfectly align with the practical application requirements of the technical specifications. When compared to existing Ku-band PAs, our design reflects a deeper consideration of specific requirements in satellite communication, ensuring its outstanding performance and uniqueness. This PA features good stability, high linearity, low cost, and compact modularity, ensuring continuous and stable power output. These features position the proposed system as a leader within the market. Successful orbital deployment not only validates its operational stability; it also makes a significant contribution to the advancement of China's satellite PA technology, generating positive socio-economic benefits.

Suppression of Multi-Harmonic Currents in the High-Speed Magnetically Suspended Motor Based on Adaptive Cascaded Notch Filters with Variable Phase Angle

Rotor imbalance is identified as one of the predominant vibration sources in high-speed magnetically suspended motors. Due to factors such as rotor machining accuracy errors and uneven material distribution, synchronous vibration interference is caused. Moreover, sensor runout generates harmonic currents, which are attributed to material irregularities and inhomogeneity in the roundness of the sensor detection surface. Harmonic currents can generate harmonic vibrational forces that are transmitted to the motor housing, jeopardizing control accuracy and the device’s operational lifespan. In order to achieve real-time reduction of harmonic currents at specified frequencies and improve the accuracy of harmonic suppression, this paper proposes an algorithm for variable phase angle filtering of an adaptive cascaded mode notch filter. This paper performed dynamic modeling and analysis of the magnetically suspended rotor system with rotor imbalance and verified the correctness of the dynamic model. Subsequently, the structure of an adaptive notch filter with variable phase angle is introduced, highlighting the capability to maintain stability by adjusting the compensatory phase of the system. By comparing the harmonic current suppression performance of cascaded and parallel mode notch filters, the cascaded method can better enhance the overall frequency selectivity, emphasizing its ability to adjust the compensation phase based on the phase angle of the input signal at different frequencies to maintain system stability. Simulation and experimental results show that harmonic currents can be successfully suppressed in the cascade mode, and the amplitude of the synchronous frequency current is reduced by 94.4[Formula: see text].

A wide drive frequency matching method for harmonic suppression and voltage stabilization of ultrasonic motors.

To reduce harmonic components, balance system impedance, and stabilize driving voltage, an additional matching circuit is required for ultrasonic motors (USMs) driver. However, the performance of inductor or capacitor matching can be seriously weakened with changes in driving frequency. Therefore, this paper presents a simple and effective LC matching method against driving frequency adjustment for USMs. First, the driving scheme of the USM is proposed and the electromechanical coupling model is analyzed. Subsequently, the output characteristics of the full-bridge inverter are derived theoretically when the driving frequency deviates from the mechanical resonant frequency. Then, the impedance circular transform method is proposed, which can intuitively analyze the effect of matching parameters on the voltage amplitude. A matching objective function is established that can consider both the voltage stabilization and harmonic suppression. The matching parameters are solved using random weight particle swarm optimization. Simulations and experiments demonstrate that within the operating frequency of the USM, the proposed matching method can effectively prevent overvoltage and suppress harmonic components. Furthermore, compared with the existing resonant matching method, the proposed matching method can realize more stable driving capability at different frequencies. The proposed method could be useful for USMs' variable-frequency driver design.

A novel 3D metal printing in‐line bandpass filter with multiple controllable transmission zeros

AbstractIn this paper, a novel three‐pole bandpass filter with a pair of controllable transmission zeros (TZs) is proposed first. The proposed structure is based on asymmetric dual‐postresonators and two external resonators. The fundamental mode and the first higher mode of the asymmetric dual‐postresonators are used as the nonresonant mode and the resonant mode separately. The nonresonant mode generates direct source to load negative coupling, thus providing one TZ located below the passband. The asymmetric dual‐postresonators and one of the external resonators R3 form a magnetically coupled cascaded triplet unit to produce the other TZ above the passband. Therefore, these two TZs are independently controlled. Moreover, the filter has a good quality factor (), of around 2700, compact size and an excellent out‐of‐band performance. For further suppressing the harmonic response and improving the processing accuracy, a six‐pole bandpass filter with harmonic suppression is designed and fabricated by using metal 3D printing technology. The measured result matches well with the simulated one, which verifies the accuracy of the method.

Efficiency Improvement and Harmonic Suppression of Single-Wire Power Transmission System Through Compensation Network

Efficiency Improvement and Harmonic Suppression of Single-Wire Power Transmission System Through Compensation Network

Harmonic Suppression for PMSM Applied to MSTMP Based on Virtual Even-Order Fractional Repetitive Controller

Harmonic Suppression for PMSM Applied to MSTMP Based on Virtual Even-Order Fractional Repetitive Controller