Harmonic Suppression Control Research Articles

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.

Harmonic suppression control strategy of distribution networks based on the distributed power flow controller

New energy and multiple loads, such as distributed wind–solar storage and charging, are connected to the distribution network through power electronic converters, which increases the harmonic content in the distribution network and causes operational safety risks. In this paper, the mathematical model of harmonic current and harmonic power content in a distribution network is constructed by an equivalent circuit and vector diagram. The distributed power flow controller is proposed for harmonic control of the distribution network. The mathematical expressions of the harmonic current and harmonic power based on a distributed power flow controller are constructed, and the control strategy of the distributed power flow controller for harmonic control is proposed. The simulation results show that the proposed method can effectively suppress the fifth and seventh harmonics of the distribution network.

Self-Constructing Chebyshev Fuzzy Neural Complementary Sliding Mode Control and Its Application.

In this article, a complementary sliding mode (CSM) controller using a self-constructing Chebyshev fuzzy recurrent neural network (SCCFRNN) is proposed for harmonic suppression control of an active power filter (APF). The SCCFRNN whose structure can be automatically learned through the designed structure self-learning algorithm is introduced to approximate the unknown nonlinear term in the APF dynamic model, so as to improve modeling accuracy and reduce the burden of CSM control (CSMC). The SCCFRNN combines the advantages of a fuzzy neural network (FNN), recurrent neural network (RNN), and Chebyshev neural network (CNN), and all parameters can be adjusted according to the designed adaptive laws. Eventually, through detailed simulation, hardware experiments, and fair comparison, the feasibility and superiority of the proposed control algorithm were verified.

An Accurate Harmonic Current Suppression Strategy for DC-Biased Vernier Reluctance Machines Based on Adaptive Notch Filter

This paper proposes an accurate harmonic current suppression strategy for DC-biased VRMs based on adaptive notch filter (ANF) to reduce torque ripple and power loss. A new harmonic reference frame (HRF) is proposed in dq-axis and combined with ANF, thus harmonic currents are accurately extracted and analyzed. Furthermore, a phase shift strategy is proposed for DC-biased VRMs, realizing precise compensation of harmonic voltages. The proposed ANF based harmonic currents suppression strategy has a better performance in harmonic suppression and dynamic response and is suitable for a wider speed range in comparison with traditional harmonic suppression control strategy. Whats more, the parameter design of the proposed method is easier compared with traditional method. Finally, the conclusions are verified by experimental results.

Microgrid reactive power compensation and harmonic suppression control method based on master-slave SVG

In order to solve the problems of power factor decline and power quality degradation caused by a large number of nonlinear loads in microgrids, this paper proposes a master-slave SVG and its control method. The master SVG usually has a large capacity and a low switching frequency. It adopts the indirect current control method to mainly compensate the reactive power of the grid. Due to the characteristics of the SVG converter itself, a certain degree of harmonics will also be generated during operation. This part of the harmonics and the harmonics of the grid itself are compensated by the slave SVG. In the harmonic extraction method, the harmonic extraction method based on instantaneous power theory is adopted. Because the harmonic content in the power grid is small, the capacity of the slave SVG is much smaller than that of the master SVG, so that each part can be fully utilized and has a strong economic efficiency. Finally, the effectiveness of the method proposed in this paper is verified by simulation.

Novel Generalized Notch Filter for Harmonic Vibration Suppression in Magnetic Bearing Systems

Magnetic bearings represent an important alternative to conventional ball bearings for applications that require very low noise and vibrations. The absence of contact and friction between rotor and stator parts, combined with the use of active vibration control techniques, result in rotating machinery that can greatly outperform their passive counterparts. One of the main disadvantages of these systems is the increased complexity of requiring the active control of the rotor, including sensors actuators and computing power. Furthermore, active vibration control techniques are generally difficult to implement over a broad speed range due to requirement of choosing and adapting different parameters to guarantee its stability. For this reason, this article presents a novel generalized notch filter for harmonic suppression control for magnetically levitated rotors, which features improved stability properties. The proposed harmonic or unbalance force rejection control is based on an unbalance and resonance suppression technique originally developed for piezoelectric active bearings for rotating machinery, and it is successfully adapted and its performance validated for machines featuring magnetic bearings. The formulation of the harmonic suppression control technique is introduced, its stability for magnetic bearing systems is analyzed, and experimentally implemented and tested on a fully active slotless Lorentz-type magnetic bearing motor obtaining a reduction of at least one order of magnitude in the level of generated vibrations.

Power Quality Control Method of Distributed Generation Based on Improved PI and Repetitive Control

In view of the similar structure between the distributed generation (DG) inverter and the active power filter (APF), it is of great significance to develop the DG inverters with harmonic suppression functions. The accurate tracking and rapid response to the phase and amplitude of the harmonic components is the guarantee of the effective use of the DG inverter to suppress the harmonic. In this paper, a harmonic suppression control method of DG inverter based on improved PI and repetitive control is proposed. This method can make the DG inverter output the active power of the fundamental wave by using the PI controller, and output the high precision harmonic current compensation by the repetitive controller. While considering the existence of a periodic delay in the repetitive controller, the feedforward control of harmonic components is added to speed up the dynamic response of harmonic suppression. Finally, the simulation results show that, compared with the traditional harmonic suppression method, the proposed control strategy can ensure the steady-state accuracy and dynamic response speed of the active output and harmonic suppression of the DG inverter while reducing the computational complexity.

A new protection strategy of impressed current cathodic protection for ship

Corrosion is never avoided in the use of materials with various environments. The underwater hull is normally protected against rusting by several coatings of anti-corrosive paint. The purpose of ICCP (impressed Current Cathodic Protection) system is to eliminate the rusting or corrosion, which occurs on metal immersed in seawater. The anode of ICCP system is controlled by an external DC source with converter. The function of anode is to conduct the protective current into seawater. The proposed algorithm includes the harmonic suppression control strategy and the optimum protection strategy and has tried to test the requirement current density for protection, the influence of voltage, the protection potential. This paper was studied the variation of potential and current density with environment factors, time and velocity, and the experimental results will be explained.

A New Control Algorithm for Impressed Current Cathodic Protection on the Underwater Hull

Cathodic protection is a system of preventing corrosion by forcing all surfaces of a hull to be cathode by providing external anodes. A metal can be made cathodic by electrically connecting it to a more anodic metal within the electrolyte. Anodes of these metals corrodepreferentially, the corrosion current of the anode achieving cathodic protection of the underwater hull to which they are connected. This paper presents a new current control algorithm for ICCP (Impressed Current Cathodic Protection) system. The anode of ICCP system is controlled by an external DC source with converter. The function of anode is to conduct the protective current into seawater. The DC source is generally obtained from main power system that contains a transformer, converter and etc. The proposed algorithm can operate AC-DC converter with current link. This algorithm includes the harmonic suppression control strategy and the optimum protection strategy and has tried to test the requirement current density for protection, the influence of voltage, the protection potential. Also, the properties of ICCP protected hull of ship in seawater are evaluated.