A new method of damping harmonic resonance at the DC link in large-capacity rectifier-inverter systems using a novel regenerating scheme

Liu

IEEE Trans. Power Electron.

2019

A two-terminal active capacitor concept is proposed recently based on an active power electronic circuit with a voltage control method and self-power scheme. It retains the convenience of use as a passive capacitor with two power terminals only without any additional required connections, and has the potential to either increased power density or reduced design cost depending on the applications. Based on the previously proof-of-concept study, this paper addresses the design constraints, impedance modeling, and start-up solutions of two-terminal active capacitors. A design method for functionality, efficiency, lifetime and cost constraints application is applied to size the active components and passive elements. A voltage feed-forward control scheme is implemented to improve its dynamic response. Two start-up solutions are proposed to overcome the issues brought by the self-power scheme. A case study of an active capacitor for the DC link of a singlephase full-bridge rectifier is presented to demonstrate the theoretical analyses.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

On the Practical Design of a Two-Terminal Active Capacitor

Liu

IEEE Trans. Power Electron.

2019

“…The AC-DC converter is by far the largest group of power switching circuits applied in industrial applications [1][2][3]. Usually rectifiers are developed using diodes and thyristors to provide uncontrolled and controlled DC power at the output with unidirectional and bidirectional power flow [4].…”

Section: Introductionmentioning

confidence: 99%

Power Quality Analysis of Controlled Rectifiers and their Impact on Input Power System

Ghaffar

2018

SJET

Pakistan these days facing major energy crisis especially in the power sector. But to overcome these crisis major companies and the govt. of Pakistan is playing vital role so that supply could meet the demand. In association to this a major project National Power System Expansion Plan 2011-2030 has started which further increases the complexity of power system, but one thing in which these power companies are lagging is in the improvement of power quality. This paper introduces the power quality analysis of AC-DC converter topologies and their impact on input power system. Due to latest advancement in the technologies and its usage it is impossible to put barriers for the applications of power electronics topologies. These topologies are of different structure and causes harmonics when connected to the power system, these harmonics affects the power quality of the system network. Due to their wide usage it necessary to observe their impact on the input power system, which includes THD (total harmonic distortion) and distortion in the input power factor etc. This research work focuses on the power quality analysis of the power system. In this paper input THD of single-pulse, two-pulse and six-pulse controlled rectifier are analysed using FFT analysis in MATLAB and their effect on input power system are also discussed.

“…However, the above filter is designed with a resonant frequency above the switching frequency, since the purpose is to limit merely dv/dt and not to suppress the switching harmonics. Another design method where a resistor is connected in series with the filter inductor to damp harmonic resonance at the DC link of a rectifier-inverter system is proposed in [19]. A detailed analysis of a split-capacitor with resistive (SC-R) damping for a LCL filter used in a three-phase grid connected inverter that includes power loss in the damping resistance in the analysis is done in [20].…”

Section: Introductionmentioning

confidence: 99%

Power Quality Improvement in a Cascaded Multilevel Inverter Interfaced Grid Connected System Using a Modified Inductive–Capacitive–Inductive Filter with Reduced Power Loss and Improved Harmonic Attenuation

Jayaraman

2017

Energies

Recently, multilevel inverters are more researched due to the advantages they offer over conventional voltage source inverters in grid connected applications. Passive filters are connected at the output of these inverters to produce sinusoidal waveforms with reduced harmonics and to satisfy grid interconnection standard requirements. This work proposes a new passive filter topology for a pulse width modulated five-level cascaded inverter interfaced grid connected system. The proposed passive filter inserts an additional resistance-capacitance branch in parallel to the filter capacitor of the traditional inductive–capacitive–inductive filter in addition to a resistance in series with it to reduce damping power loss. It can attenuate the switching frequency harmonic current components much better than the traditional filter while maintaining the same overall inductance, reduced capacitance and resistance values. The basic parameter design procedure and an approach to discover the parameters of the proposed filter is introduced. Further, a novel methodology using Particle Swarm Optimization (PSO) is recommended to guarantee minimum damping loss while ensuring reduced peak during resonance. In addition, PSO algorithm is newly employed in this work to maximize harmonic attenuation in and around the switching frequency on the premise of allowable values of filter inductance and capacitance. A comparative discussion considering traditional passive filters and the proposed filter is presented and evaluated through experiments conducted on a 110 V, 1 kW five-level grid connected inverter. The modulation algorithm for the multilevel inverter is implemented using a SPARTAN 6-XC6SLX25 Field Programmable Gate Array (FPGA) processor. The analysis shows that the proposed filter not only provides decreased damping power loss but also is capable of providing considerable harmonic ripple reduction in the high frequency band, improved output waveforms and lesser Total Harmonic Distortion (THD) with improved power quality for the multilevel inverter based grid connected system.