Design and Analysis of Multiple-Loop Control Schemes Applied to a Front-end Rectifier

2020 ◽  
Author(s):  
Divakar ◽  
Prakash Dwivedi ◽  
Sourav Bose
Keyword(s):  
Loop Control ◽  
Front End ◽  
Control Schemes

Active Control of Combustion Instability Using Symmetric and Asymmetric Premix Fuel Modulation

2007 ◽  
Author(s):  
Daniel Guyot ◽  
Christian Oliver Paschereit
Keyword(s):  
Heat Release ◽  
Closed Loop ◽  
Modulation Frequency ◽  
Combustion Instability ◽  
Open Loop ◽  
Closed Loop Control ◽  
Nox Emissions ◽  
Loop Control ◽  
Asymmetric Modulation ◽  
Control Schemes

Active instability control was applied to an atmospheric swirl-stabilized premixed combustor using open loop and closed loop control schemes. Actuation was realised by two on-off valves allowing for symmetric and asymmetric modulation of the premix fuel flow while maintaining constant time averaged overall fuel mass flow. Pressure and heat release fluctuations in the combustor as well as NOx, CO and CO2 emissions in the exhaust were recorded. In the open loop circuit the heat release response of the flame was first investigated during stable combustion. For symmetric fuel modulation the dominant frequency in the heat release response was the modulation frequency, while for asymmetric modulation it was its first harmonic. In stable open loop control a reduction of NOx emissions due to fuel modulation of up to 19% was recorded. In the closed loop mode phase-shift control was applied while triggering the valves at the dominant oscillation frequency as well as at its second subharmonic. Both, open and closed loop control schemes were able to successfully control a low-frequency combustion instability, while showing only a small increase in NOx emissions compared to, for example, secondary fuel modulation. Using premixed open loop fuel modulation, attenuation was best when modulating the fuel at frequencies different from the dominant instability frequency and its subharmonic. The performance of asymmetric fuel modulation was generally slightly better than for symmetric modulation in terms of suppression levels as well as emissions. Suppression of the instability’s pressure rms level of up to 15.7 dB was recorded.

Dynamic Simulation and Control of a Roller Conveyor

2019 ◽  
Author(s):  
Bradford Range
Keyword(s):  
Material Handling ◽  
Dynamic Control ◽  
Control Unit ◽  
Optimal Number ◽  
Sensitivity Analyses ◽  
Roller Conveyor ◽  
Loop Control ◽  
Simulation And Optimization ◽  
Control Schemes ◽  
Loading System

Abstract Passive roller conveyors are frequently used in material handling applications to transport objects of various sizes and shapes. Passive systems cannot control unit flow, leading to queues and system jams. In this paper we analyze the performance of a gravity-driven roller conveyor with brakes selectively installed on rollers to control package flow in the load lanes of a transportation hub. Dynamics of the rollers and kinematic interaction with boxes on the conveyor were derived and fully modeled in MATLAB to simulate accurate conveyor behavior. Sensitivity analyses were performed to evaluate the effect of friction, box mass, roller inertia, and other factors. Using heuristic data to define boundary conditions (box weight, size, and input frequency), several control cases were evaluated. Performance was defined by buffering efficiency of the conveyor, or how effectively the conveyor “kept pace” with a person moving boxes from the load conveyor onto a waiting truck. Several dynamic control cases were simulated. It was found that the optimal number of installed brakes is 30% of the total rollers on the conveyor. Even rudimentary brake control schemes (applying a simple duty-cycle on/off to roller brakes) had the potential to increase the conveyor buffer efficiency by 10% over baseline, with the potential for much greater benefits from more “intelligent” closed-loop control schemes. The simulation and optimization of the active roller conveyor gave insights into the behavior of their truck loading system and identified several ways to increase loading efficiency.

Simulation and Control of a Commercial Double Effect Evaporator: Tomato Juice

2010 ◽  
Vol 5 (1) ◽  
Author(s):  
Praveen Yadav ◽  
Amiya K Jana
Keyword(s):  
Double Effect ◽  
Open Loop ◽  
Simulation Experiments ◽  
Loop Control ◽  
Process Dynamics ◽  
Point Tracking ◽  
Tomato Paste ◽  
Control Schemes ◽  
And Control ◽  
Gain Scheduled

This work aims to present a detailed study on a commercial double-effect tomato paste evaporation system. The modeling equations formulated for process simulation belong to backward feeding arrangement. Open-loop process dynamics has been studied by rigorous simulation of the model structure. In the next, three multi-loop control schemes, namely conventional proportional integral (PI), gain-scheduled PI (GSPI) and nonlinear PI (NLPI), have been synthesized for the sample process. Finally, several simulation experiments have been conducted to investigate the comparative closed-loop performance based on set point tracking and disturbance rejection.

Improved Controller Performance of Selected Hybrid SOFC-GT Plant Signals Based on Practical Control Schemes

2010 ◽  
Author(s):  
Alex Tsai ◽  
David Tucker ◽  
Craig Groves
Keyword(s):  
Fuel Cell ◽  
Actuator Saturation ◽  
Filter Design ◽  
Interaction Analysis ◽  
Hybrid Plant ◽  
Internal Model Control ◽  
Department Of Energy ◽  
Loop Control ◽  
Model Control ◽  
Control Schemes

This paper compares and demonstrates the efficacy of implementing two practical Single Input Single Output (SISO) multi-loop control schemes on the dynamic performance of selected signals of a Solid Oxide Fuel Cell Gas Turbine (SOFC-GT) hybrid simulation facility. The hybrid plant, located at the U.S. Department of Energy National Energy Technology Laboratory (NETL) in Morgantown WV, is capable of simulating the interaction between a 350kW SOFC and a 120kW GT using a Hardware-in-the-Loop (HIL) configuration. Previous studies have shown that the thermal management of coal based SOFC-GT hybrid systems is accomplished by the careful control of the cathode air stream within the fuel cell (FC). A decoupled centralized and dynamic de-centralized control scheme is tested for one critical airflow bypass loop to regulate cathode FC airflow and modulation of turbine electric load to maintain synchronous turbine speed during system transients. Improvements to the studied multivariate architectures include: feed-forward (FF) control for disturbance rejection, anti-windup (AW) compensation for actuator saturation, gain scheduling for adaptive operation, bumpless transfer (BT) for manual to auto switching, and adequate filter design for the inclusion of derivative action. Controller gain tuning is accomplished by Skogestad’s Internal Model Control (SIMC) tuning rules derived from empirical First Order Plus Delay Time (FOPDT) Transfer Function {TF} models of the hybrid facility. Avoidance of strong Input-Output (IO) coupling interactions is achieved via Relative Gain Array (RGA), Niederlinski Index (NI), and Decomposed Relative Interaction Analysis (DRIA), following recent methodologies in PID control theory for multivariable processes.

A simulation approach for closed-loop control of coupled four tank system

2021 ◽  
Author(s):  
Nasim Ullah ◽  
Alsharef Mohammad
Keyword(s):  
Fractional Order ◽  
Sliding Mode ◽  
Pid Controllers ◽  
Major Step ◽  
Process Industries ◽  
Loop Control ◽  
Step Model ◽  
Control Schemes ◽  
Tank System ◽  
Fractional Order Pid

The coupled tank system is the most widely used sub-component in chemical process industries. Fluid mixing is a major step in chemical processes that alters the material properties and cost. Fluid flow and its level regulation between several tanks are important control problems. As the first step, this paper addresses the level regulation problem using classical integer order proportional, derivative, integral (PID), fractional order PID controllers. As a second step, model-based robust fractional order controllers are derived using sliding mode approach in order to achieve the desired response, parameters of the proposed controllers are tuned using genetic algorithm. Finally, system performance under all variants of control schemes has been tested using numerical simulations.

In-Hand Manipulation Primitives for a Minimal, Underactuated Gripper With Active Surfaces

2016 ◽  
Author(s):  
Raymond R. Ma ◽  
Aaron M. Dollar
Keyword(s):  
A Priori ◽  
Open Loop ◽  
Object Motion ◽  
A Priori Knowledge ◽  
Open Loop Control ◽  
Loop Control ◽  
Grasp Stability ◽  
Control Schemes ◽  
And Control ◽  
Underactuated Finger

Dexterous in-hand manipulation tasks have been difficult to execute, even with highly complex hands and control schemes, as the object grasp stability needs to be maintained while it is displaced in the hand workspace. Researchers have shown that underactuated, adaptive hand designs can effectively immobilize objects with simple, open-loop, but there have been few cases where underactuation has been leveraged to enhance in-hand manipulation. In this work, we investigate the performance of a gripper utilizing a thumb with an active, belt-driven, conveyor surface and an opposing, underactuated finger with passive rollers, for a variety of manipulation tasks and range of objects. We show that consistent, repeatable object motion can be obtained while ensuring a rigid grasp without a priori knowledge of the object geometry or contact locations, due to the adaptive qualities of underactuated design. Many dexterous in-hand manipulation examples with their anthropomorphic equivalents are examined, and simple, open-loop control schemes to optimize the repeatability of these tasks are proposed.

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