Design of PI Controller Parameters of a CSI ‐fed SCIM Drive Ensuring High Damping Ratio and Maximum System Stability

2021 ◽  
Author(s):  
S. M. Tripathi ◽  
Rachna Vaish ◽  
A. K. Pandey
Keyword(s):  
Damping Ratio ◽  
Pi Controller ◽  
System Stability

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.

scholarly journals Assessing the Impact of DFIG Synthetic Inertia Provision on Power System Small-Signal Stability

Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3440 ◽  
Author(s):  
Edgar Lucas ◽  
David Campos-Gaona ◽  
Olimpo Anaya-Lara
Keyword(s):  
Power System ◽  
Large Scale ◽  
Damping Ratio ◽  
System Stability ◽  
Electrical Network ◽  
Small Signal ◽  
Small Signal Stability ◽  
Signal Stability ◽  
Electromechanical Modes ◽  
The Impact

Synthetic inertia provision through the control of doubly-fed induction generator (DFIG) wind turbines is an effective means of providing frequency support to the wider electrical network. There are numerous control topologies to achieve this, many of which work by making modifications to the DFIG power controller and introducing additional loops to relate active power to electrical frequency. How these many controller designs compare to one-another in terms of their contribution to frequency response is a much studied topic, but perhaps less studied is their effect on the small-signal stability of the system. The concept of small-signal stability in the context of a power system is the ability to maintain synchronism when subjected to small disturbances, such as those associated with a change in load or a loss of generation. Amendments made to the control system of a large-scale wind farm will inevitably have an effect on the system as a whole, and by making a DFIG wind turbine behave more like a synchronous generator, which synthetic inertia provision does, may incur consequences relating to electromechanical oscillations between generating units. This work compares the implications of two prominent synthetic inertia controllers of varying complexity and their effect on small-signal stability. Eigenvalue analysis is conducted to highlight the key information relating to electromechanical modes between generators for the two control strategies, with a focus on how these affect the damping ratios. It is shown that as the synthetic inertia controller becomes both more complex and more effective, the damping ratio of the electromechanical modes is reduced, signifying a decreased system stability.

scholarly journals Optimal Tuning of SVC-PI Controller using Whale Optimization Algorithm for Angle Stability Improvement

2018 ◽  
Vol 12 (2) ◽  
pp. 620
Author(s):  
N. A. M. Kamari ◽  
I. Musirin ◽  
Z. A. Hamid ◽  
A. A. Ibrahim
Keyword(s):  
Optimization Algorithm ◽  
Damping Ratio ◽  
Optimization Technique ◽  
Computation Time ◽  
Synchronous Generator ◽  
Pi Controller ◽  
Optimization Techniques ◽  
Whale Optimization Algorithm ◽  
Whale Optimization ◽  
Angle Stability

This paper proposed a new swarm-based optimization technique for tuning conventional proportional-integral (PI) controller parameters of a static var compensator (SVC) which controls a synchronous generator in a single machine infinite bus (SMIB) system. As one of the Flexible Alternating Current Transmission Systems (FACTS) devices, SVC is designed and implemented to improve the damping of a synchronous generator. In this study, two parameters of PI controller namely proportional gain, K<sub>P</sub> and integral gain, K<sub>I</sub> are tuned with a new optimization method called Whale Optimization Algorithm (WOA). This technique mimics the social behavior of humpback whales which is characterized by their bubble-net hunting strategy in order to enhance the quality of the solution. Validation with respect to damping ratio and eigenvalues determination confirmed that the proposed technique is more efficient than Evolutionary Programming (EP) and Artificial Immune System (AIS) in improving the angle stability of the system. Comparison between WOA, EP and AIS optimization techniques showed that the proposed computation approach gives better solution and faster computation time.

scholarly journals Design of a Damping Controller Using a Metaheuristic Algorithm for Angle Stability Improvement of an SMIB System

2022 ◽  
Vol 12 (2) ◽  
pp. 589
Author(s):  
Abdul Waheed Khawaja ◽  
Nor Azwan Mohamed Kamari ◽  
Muhammad Ammirrul Atiqi Mohd Zainuri
Keyword(s):  
Power Systems ◽  
Damping Ratio ◽  
Dynamic Performance ◽  
Low Frequency ◽  
Optimal Solution ◽  
System Stability ◽  
Large Power ◽  
Low Frequency Oscillations ◽  
Effective Role ◽  
Single Machine Infinite Bus

Low frequency oscillations in large power systems may result in system instability under large disturbances. Power system stabilisers (PSS) play an effective role in damping these low frequency oscillations by injecting a modulating signal in the excitation loop of a synchronous machine. A new metaheuristic optimisation algorithm termed the sine cosine algorithm (SCA) was proposed for optimising PSS controller parameters to obtain an optimal solution with the damping ratio as an objective function. The SCA technique was examined on a single machine infinite bus (SMIB) system under distinct loading situations and matched with a moth flame optimisation technique and evolutionary programming to design a robust controller of PSS. The simulation was accomplished using a linearised mathematical model of the SMIB. The performance of a designed lead lag-controller of PSS was demonstrated using eigenvalue analysis with simulations, showing promising results. The dynamic performance was validated with respect to the damping ratio, the eigenvalue’s location in the s-plane and rotor angle deviation response to demonstrate system stability.

A Brief Study of Passive Viscous Damping for the SPICE Bulkhead Structure

1993 ◽  
Author(s):  
Thomas J. Thompson ◽  
Joseph R. Baumgarten
Keyword(s):  
Active Control ◽  
Damping Ratio ◽  
System Stability ◽  
Structural Vibration ◽  
Line Of Sight ◽  
Viscous Damping ◽  
Frequency Range ◽  
Filament Wound ◽  
On Line ◽  
Specific Increase

Abstract The SPICE Testbed at Phillips Laboratory is being used to evaluate the effects of structural vibration on line-of-sight error for this strut built structure. A design incorporating active control and passive damping techniques is suggested to reduce the optical path distortion created in the vibrating structure. The passive viscous damping applied to the structure serves to aid the active control system stability in the cross-over and spill-over frequency range by producing a specified magnitude of damping in specified critical modes. This magnitude of damping is to be achieved by replacing the standard filament wound undamped struts with optimally placed D-struts which contain series and parallel combinations of springs and viscous dampers and produce damped vibration response from in-line strut deflection. This D-strut must replace standard struts in a tear-down of the bulkhead. The present study proposes to provide the requisite damping by adding on viscous damping at diagonal nodal locations in the bulkhead, circumventing the need to disassemble the SPICE bulkhead. The study shows specific increase in loss factor and improved damping ratio provided by the diagonal dampers when compared to in-line D-struts for specific modes and frequencies.

Switch-Mode Continuously Variable Transmission: Modeling and Optimization

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
James D. Van de Ven ◽  
Michael A. Demetriou
Keyword(s):  
State Space ◽  
Damping Ratio ◽  
High Energy ◽  
Continuously Variable Transmission ◽  
Drive Train ◽  
System Stability ◽  
High Energy Density ◽  
Duty Ratio ◽  
Switch Mode ◽  
Variable Transmission

Hybrid vehicles are an important step toward reducing global petroleum consumption and greenhouse gas emissions. Flywheel energy storage in a hybrid vehicle combines high energy density and high power density, yet requires a highly efficient continuously variable transmission with a wide operating range. This paper presents a novel solution to coupling a high-speed flywheel to the drive train of a vehicle, the switch-mode continuously variable transmission (CVT). The switch-mode CVT, the mechanical analog of a boost converter from power electronics, utilizes a rapidly switching clutch to transmit energy from a flywheel to a spring, which applies a torque to the drive train. By varying the duty ratio of the clutch, the average output torque is controlled. This paper examines the feasibility of this concept by formulating a mathematical model of the switch-mode CVT, which is then placed in state-space form. The state-space formulation is leveraged to analyze the system stability and perform simple optimization of the switch time and damping rate of the spring over the first switching period. The results of this work are that a stable equilibrium does exist when the speed of the output shaft is zero, but the system will not reach and stay at a desired torque if this condition is not met, but requires continuous switching between the two states. An optimal switching time and damping ratio were found for the given parameters, where the lowest error occurred with low values of damping ratio. This work builds a foundation for future work in increasing the complexity of the model and the optimization method.

scholarly journals Small-Signal Modeling and Analysis of Grid-Connected Inverter with Power Differential Droop Control

2016 ◽  
Vol 2016 ◽  
pp. 1-10
Author(s):  
Xin Chen ◽  
Changhua Zhang ◽  
Qi Huang ◽  
Mark Ofori-Oduro
Keyword(s):  
Control Method ◽  
Control Strategies ◽  
Damping Ratio ◽  
Low Frequency ◽  
System Stability ◽  
Droop Control ◽  
Small Signal ◽  
System Matrix ◽  
Power Differential ◽  
Grid Connected Inverter

The conventional voltage and frequency droop control strategy in grid-connected inverter suffers a major setback in the presence of disturbance by producing oscillations. Adding a power differential term in droop controller is an effective way to address such drawback. In this paper, grid-connected inverter’s small-signal models of the conventional droop control and the power differential droop control are established. The eigenvalues of the models are then determined by system matrix. The eigenvalues analysis is presented which helps in identifying the relationship between the system stability and controller parameters. It is concluded that the damping ratio of dominant low-frequency eigenvalues increased and the oscillation caused by the disturbance is suppressed when a power differential term is added to the droop control method. The MATLAB/Simulink models of grid-connected inverter with both control strategies are also established to validate the results of small-signal analysis.

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