Stability Regions of Nonlinear LCL-Filtered Converter with Converter-Current-Feedback Control Without Damping

2018 ◽  
Vol 22 (5) ◽  
pp. 629-639
Author(s):  
Qingyi Wang ◽  
Xuefen Wang ◽  
Min Ding ◽  
Quan Yin ◽  
Haichun Li ◽  
...  
Keyword(s):  
Feedback Control ◽  
Model Simulation ◽  
System Stability ◽  
Nyquist Diagram ◽  
Current Feedback ◽  
Stability Regions ◽  
Transport Delay ◽  
Control Frequency ◽  
Internal Loss ◽  
The Stability

The stability regions of a LCL-filtered converter adopting converter-current-feedback control without damping are analyzed. The nonlinear LCL-filtered model is presented to investigate its influence on the system stability. The stability analysis is performed by means of the Nyquist diagram in s domain. It reveals that three factors have the dominant effects on the system stability, including internal loss of LCL-filtered model, PWM transport delay and controller parameters. The undamped stability boundaries of the system gain calculated by the symmetrical optimum method are obtained. It can be found that stable regions for the nonlinear LCL-filtered system are extended into a continuous region of ratios of LCL filter resonance frequency to control frequency from three distinct regions. Finally, the stable regions are validated by the nonlinear model simulation, and experimental results verify the theoretical analysis.

Study on Gyroscopic Effect of Magnetic Flywheel Rotor

2011 ◽  
Vol 130-134 ◽  
pp. 970-975
Author(s):  
Xiang Long Wen ◽  
Cao Cao
Keyword(s):  
Feedback Control ◽  
High Speed ◽  
System Stability ◽  
Rotor Speed ◽  
Gyroscopic Effect ◽  
Pd Control ◽  
The Stability ◽  
Gyroscopic Effects ◽  
Zero Points ◽  
Flywheel Rotor

In the high-speed, gyroscopic effects of the flywheel rotor greatly influence the rotor stability. The pole-zero points move to right of s-plane and the damping terms of the pole points become smaller. The stability of the system will get worse with the increasing of rotor speed when the traditional decentralized PD controller is used only. In the paper, a cross-feedback control with decentralized PD control is used for compensating gyroscopic effect. The simulation results show that the system stability is better using the cross-feedback control with decentralized PD control than using the traditional decentralized PD control.

scholarly journals Enhancing the Stability of an Autonomous Microgrid Using DSTATCOM

2010 ◽  
Vol 10 (5) ◽  
Author(s):  
Ritwik Majumder ◽  
Arindam Ghosh ◽  
Gerard Ledwich ◽  
Firuz Zare
Keyword(s):  
Power Sharing ◽  
System Stability ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Voltage Reference ◽  
Current Feedback ◽  
Distributed Generators ◽  
The Stability ◽  
Power Outputs ◽  
Static Compensator

This paper proposes a method for enhancing stability of an autonomous microgrid with distribution static compensator (DSTATCOM) and power sharing with multiple distributed generators (DG). It is assumed that all the DGs are connected through voltage source converter (VSC) and all connected loads are passive, making the microgrid totally inertia less. The VSCs are controlled by either state feedback or current feedback mode to achieve desired voltage-current or power outputs, respectively. A modified angle droop is used for DG voltage reference generation. Power sharing ratio of the proposed droop control is established through derivation and verified by simulation results. A DSTATCOM is connected in the microgrid to provide ride through capability during power imbalance in the microgrid, thereby enhancing the system stability. This is established through extensive simulation studies using PSCAD.

scholarly journals Enhancement of mobile scissor lifting system for windy environments

2021 ◽  
Vol 40 (2) ◽  
pp. 229-240
Author(s):  
K.E. Jack ◽  
U.A. Essien ◽  
O.S. Bamisaye ◽  
K.O. Paul ◽  
E.E. Ozoemela ◽  
...  
Keyword(s):  
Model Simulation ◽  
Control Unit ◽  
System Stability ◽  
Strong Wind ◽  
Electronic Control ◽  
Development Environment ◽  
Load Range ◽  
The Stability ◽  
Lifting System ◽  
Near Future

This paper focuses on the enhancement of mobile scissor lifting system for windy environments. This study was necessitated in order to address the lack of support arm problem on the mobile scissor lifting system for the strong wind environment such as Minna in Niger State Nigeria. The outstation broadcasting operations in Minna metropolis are usually challenging during windy days as wind often affects the stability and efficiency of the outstation broad-casting platforms. This research employs electronic control circuit to control mechanical hydraulic actuated scissor lifting system in response to variations in wind speed. The mechanical components were designed using solidworks software. The control unit was remodeled using Proteus 8.0 software with the code written in Arduino integrated development environment (IDE). The model simulation results for both electronic and mechanical system reveal the possibility of achieving system stability with the resultant signal fidelity in outstation telecommunication broad-cast within windy areas. The experiment result shows that the system was capable of lifting the telecommunication platform 2 meters high within 20 seconds considering the load range of 500 to 1000 kg. An overload alert mechanism was incorporated to signal the operators of excessive loading. Then, the system automatically deploys its support arms to counter the attendant consequences of the strong wind thereby restoring the stability of the mobile scissor lift. Therefore, the authors conclude that the enhanced mobile scissor lifting system would be deployed in the windy environment for the maximum attainment of stability objectives while physical model from this design should be subsequently fabricated in the near future.

Stability of Ring-Type MEMS Gyroscopes Subjected to Stochastic Angular Speed Fluctuation

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Samuel F. Asokanthan ◽  
Soroush Arghavan ◽  
Mohamed Bognash
Keyword(s):  
Angular Velocity ◽  
Degrees Of Freedom ◽  
Microelectromechanical Systems ◽  
Damping Ratio ◽  
Operating Conditions ◽  
System Stability ◽  
System Response ◽  
Ring Type ◽  
Mems Gyroscopes ◽  
The Stability

Effect of stochastic fluctuations in angular velocity on the stability of two degrees-of-freedom ring-type microelectromechanical systems (MEMS) gyroscopes is investigated. The governing stochastic differential equations (SDEs) are discretized using the higher-order Milstein scheme in order to numerically predict the system response assuming the fluctuations to be white noise. Simulations via Euler scheme as well as a measure of largest Lyapunov exponents (LLEs) are employed for validation purposes due to lack of similar analytical or experimental data. The response of the gyroscope under different noise fluctuation magnitudes has been computed to ascertain the stability behavior of the system. External noise that affect the gyroscope dynamic behavior typically results from environment factors and the nature of the system operation can be exerted on the system at any frequency range depending on the source. Hence, a parametric study is performed to assess the noise intensity stability threshold for a number of damping ratio values. The stability investigation predicts the form of threshold fluctuation intensity dependence on damping ratio. Under typical gyroscope operating conditions, nominal input angular velocity magnitude and mass mismatch appear to have minimal influence on system stability.

Design of Electrostatic Precipitator Power System Based on Auto Disturbance Rejection Controller

2013 ◽  
Vol 846-847 ◽  
pp. 190-194
Author(s):  
Shu Jun Yin ◽  
Xue Ren Li ◽  
Ji Geng Luo
Keyword(s):  
Power Supply ◽  
Disturbance Rejection ◽  
Power Supply System ◽  
Electrostatic Precipitator ◽  
Supply System ◽  
System Stability ◽  
Engineering Practice ◽  
Single Chip ◽  
High Voltage Power Supply ◽  
The Stability

The paper designs a three-phase high voltage power supply system based on active disturbance rejection controller which make single-chip microcomputer ATmega128 as the main control chip and the system improve the stability and control precision of dust removing power. Engineering practice shows that, the DC power supply system has the advantages of convenient operation, high work efficiency, system stability.

A Quasiperiodic Mathieu Equation

1995 ◽  
Author(s):  
Richard Rand ◽  
Rachel Hastings
Keyword(s):  
Numerical Integration ◽  
Mathieu Equation ◽  
Stability Regions ◽  
Regions Of Stability ◽  
Extensive Computation ◽  
The Stability ◽  
Direct Numerical Integration

Abstract In this work we investigate the following quasiperiodic Mathieu equation: x ¨ + ( δ + ϵ cos ⁡ t + ϵ cos ⁡ ω t ) x = 0 We use numerical integration to determine regions of stability in the δ–ω plane for fixed ϵ. Graphs of these stability regions are presented, based on extensive computation. In addition, we use perturbations to obtain approximations for the stability regions near δ=14 for small ω, and we compare the results with those of direct numerical integration.

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