Design Of Proportional Integral Controller Research Articles

Cascade Proportional-Integral Control Design and Affordable Instrumentation System for Enhanced Performance of Electrolytic Dry Cells.

In this paper, we present a cost-effective system for monitoring and controlling alkaline electrolyzers, intending to improve hydrogen gas production on a laboratory scale. Our work includes two main innovations. Firstly, we suggest an approach to calibrate a standard air flow meter to accurately measure the flow of hydrogen-rich gas from electrolyzers, improving measurement accuracy while keeping costs low. Secondly, we introduce a unique cascade control method to manage hydrogen-rich gas production in the electrolyzer, ensuring precise control over gas flow rates. By combining affordable, energy-efficient devices with a PI control system, we achieve efficient gas production through electrolysis, replacing manual control approaches. Experimental results confirm the effectiveness of our cascade control method, demonstrating stable operation with minimal errors. These results provide a foundation for further research into control strategies to enhance the performance of electrolytic cells.

Design method of multivariable PI controller for turboprop engine based on equivalent transfer function

Traditional centralized Proportional Integral (PI) controller design methods based on Equivalent Transfer Functions (ETFs) have poor decoupling effect in turboprop engines. In this paper, a centralized PI design method based on dynamic imaginary matrix and equivalent transfer function is proposed. Firstly, a method for solving equivalent transfer functions based on the dynamic imaginary matrix is proposed, which adopts dynamic imaginary matrix to describe the dynamic characteristics of the system, and obtains the equivalent transfer function based on the dynamic imaginary matrix characteristics. Secondly, for the equivalent transfer function, a centralized PI control gain is designed using the Taylor expansion method. Meanwhile, this paper further proves that the centralized PI design method proposed in this paper has integral stability. Considering the impact of altitude and Mach number on turboprop engines, a linear feedforward control method based on the transfer function matrix is further proposed based on the centralized PI controller, and the stability of the entire comprehensive control method is proved. Finally, to ensure the safe and effective operation of the turboprop engine, a temperature and torque limiting protection controller is designed for the turboprop engine. Simulation results show that the centralized PI controller design method and linear feedforward control method proposed can effectively improve the control quality of turboprop engine control systems.

Gain Scheduled PI controller design using Multi-Objective Reinforcement Learning

Gain scheduling, a widely adopted control design approach, performs tasks by decomposing into sub-problems. It has found successful applications across diverse fields, including aerospace and industrial process control (Leith and Leithead (2000)). Reinforcement Learning (RL) has become increasingly significant in process control applications, thanks to the advancement of sophisticated algorithms and the rise in computational speeds. An attempt has been made to enhance the performance of a Proportional-Integral (PI) controller by integrating the benefits of both gain scheduling and RL. The manuscript focuses on designing a Gain Scheduled PI controller using Multi-Objective RL (GS-MORL). Proposing the training of multiple RL-based PI controllers with distinct objectives with customized reward functions to derive tuning parameters for each goal. The switching between these parameter sets is facilitated by a gain schedule variable. The controller parameters are adjusted based on the error between actual and desired responses. The aim is to enhance overall performance across various performance indices, including the integral of absolute error and time response specifications. The performance improvement from the proposed work has been demonstrated using two simulation case studies, one involving an underdamped second-order system and an integrating type steam turbine system. Comparative analysis against existing literature revealed superior performance across all indices.

Design, control and performance comparison of PI and ANFIS controllers for BLDC motor driven electric vehicles

The research and usage of electric vehicles (EVs), including two and four-wheeler vehicles, are rapidly increasing worldwide as alternatives to oil/gas-based vehicles. Brushless direct current (BLDC) motors are popular for industrial and traction applications due to their inherent advantages. In EVs, achieving low error in steady-state and transient responses is crucial for smooth acceleration at the wheel. This paper presents the design and control of a BLDC motor for speed control during acceleration and deceleration, considering error as a key factor in the MATLAB/Simulink environment. Proportional-integral (PI) and fuzzy controllers are commonly used for motor control to improve steady-state and transient performance, thereby reducing error. In this study, the PI and adaptive neuro-fuzzy inference system (ANFIS) controllers are designed and compared for a 5-kW, 48-V, and 100-Amp BLDC motor in EV applications. The results demonstrate that the ANFIS controller enhances the dynamic performance of the BLDC motor and improves other operating characteristics such as rise time, settling time, peak overshoot percentage and the vehicle response in terms of speed and distance.

Experimental Control of a Methanol Catalytic Membrane Reformer

A simple proportional integral (PI) controller with scheduled gain has been developed and implemented in a catalytic membrane reactor (CMR) to obtain pure hydrogen from a methanol steam reforming process. The controller is designed to track the setpoint of the pure hydrogen flow rate in the permeate side of the CMR via the manipulation of the fuel inlet flow rate. Therefore, the controller actuator is the liquid pump that provides the mixture of methanol and water to the reactor. Within the CMR, the catalytic pellets of PdZn/ZnAl2O4/Al2O3 have been used to facilitate the methanol steam-reforming reaction under stoichiometric conditions (S/C = 1), and Pd–Ag metallic membranes have been employed to simultaneously separate the generated hydrogen. The PI controller design is based on a mathematical model constructed using transfer functions acquired from dynamic experiments conducted with the CMR. The controller has been successfully implemented, and experimental validation tests have been carried out at 450 °C and relative pressures of 6, 8, 10, and 12 bar.

Design of PI Controller for a Class of Discrete Cascade Control Systems

This paper mainly studies the modeling, stability analysis and proportional-integral (PI) controller design for a class of discrete-time cascade control systems (CCSs). In the existing CCSs for solving gain of the controller, the controller mostly adopts the proportional (P) controller, but the most commonly used controller in industrial production is PI controller. Based on the actual demand in industry and in order to obtain a better control effect, the design problem of primary and secondary controllers in a class of discrete cascade control is considered, in which the primary controller adopts a PI controller and the secondary controller adopts a P controller. On this basis, the model of cascade control system (CCS) is established. Then, we can create a new Lyapunov functional, the sufficient conditions for the stability of the system is given. Then, the collaborative design method of primary PI controller and secondary P controller is given by using linear matrix inequality (LMI) technique. Finally, a simulation example of a main steam temperature with CCS structure is given to demonstrate the effectiveness of the method. The PI controller is better than the existing P controller, this method has not only the rapidity of P control, but also the ability of integral control to eliminate steady-state errors. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> — The inspiration of this paper comes from the adjustment of plant controller parameters. The PI controller is the most widely used controller in the existing industrial production, but the adjustment of proportional and integral parameters of the controller is a very troublesome thing. In order to obtain a better controller parameters, a professional engineer may spend a whole day to adjust the parameters. This paper can design the solution of the primary and secondary controller parameters to stabilize the CCS at the same time by LMI technique, which can greatly reduce the work of adjusting the controller parameters. Through simulation, we can know that this method can make the system stable, which shows this method is feasible.

Control Method of Wire Repairing Robot Based on Semantic Segmentation and Current Detection

The traditional repair of conductors in power systems, using manual work at height, carries a high level of risk. To ensure personnel safety and improve operational efficiency. Based on the development of a conductor repair robot using pre-stranded wires, the focus is on a semantic segmentation-based adaptive conductor arc sag control method, which enables the robot to adapt to conductors with different arc sags by segmentation identification of the conductor, offset calculation, and proportional-integral controller design to realize the robot hanging on the conductor. Subsequently, the winding gap is monitored according to the change of motor current, and a fuzzy controller is used to realize the robot winding operation. The robot prototype tests show that the robot is capable of adapting to the wire pitch and completing soft repair work.

Enhanced design of PI controller with lead-lag filter for unstable and integrating plus time delay processes

Abstract In this work, a proportional–integral (PI) controller with a set point filter is designed using the direct synthesis method for unstable plus time delay process. The Suggested method involves design parameters whose suitable values are recommended based on robust stability and robust performance constraints. The absence of derivative term makes PI controllers less sensitive to noise and, therefore, PI controllers are more preferable than PID in industrial applications. Despite a simple control architecture, the proposed method gives improved or comparable performance to previously presented approaches, which are comparatively complex. Four case studies are considered to evaluate the suitability and superiority of the suggested control technique. Proposed controller may be applied to the integrating plus time delay plants after some elementary transformations in the process model.

Design of optimal PI controller for torque ripple minimization of SVPWM-DTC of BLDC motor

Conventional direct torque control (CDTC) for brushless DC motor (BLDCM) using proportional integral (PI) controller suffers from torque ripple minimization and speed regulation issues. A novel method in fusion with space vector pulse width modulation (SVPWM) with DTC using optimal PI controller is developed to minimize these issues. In this method, SVPWM replaces switching table and hysteresis controllers in CDTC. To get better performance in steady state, conventional PI controllers are preferred in SVPWM-DTC for BLDCM. However, uncertainty arises due to PI controller tuning as well as load variations. In such a case, optimal PI controller tuned properly can minimize these uncertainties. Here, JAYA algorithm is used to tune controller gain parameters. Simulations of proposed PI controller of SVPWM-DTC for BLDCM are carried away in Simulink. To appreciate the performance of proposed optimal controller of SVPWM-DTC for BLDCM, the simulation results are compared with Conventional PI controller and particle swarm optimization (PSO) technique based tuned PI controller. This proposed technique reduces the toque ripple by 63.1% when compared to conventional PI and 58.5% when compared to PSO-PI controller. It also improves the settling time by 43.9% when compared to conventional PI and 46.79% when compared to PSO-PI controller.

Assessment of a High-Order Stationary Frame Controller for Two-Level and Three-Level NPC Grid-Connected Inverters

Most grid-connected DC/AC inverters use traditional proportional–integral (PI) controllers in a synchronous frame. In addition to poor disturbance rejection capabilities, these PI controllers also exhibit steady-state errors for sinusoidal reference signals. To address these drawbacks, this article investigates the use of a high-order controller in the stationary frame and then compares it with the standard PI controller. The effectiveness of the high-order controller in the stationary frame has been examined by providing an infinite gain at a resonance frequency. In this work, the design of high-order and PI controllers and tuning instructions are given. Furthermore, both high-order and PI current-controlled two-level and three-level neutral point clamped (NPC) inverters are compared. Various operational conditions are used for the comparison. The high-order controller reduced the total harmonic distortion (THD) of the injected current by 1.15% for the two-level inverter in normal conditions as compared to the PI controller and 0.9% for the three-level NPC inverters. Furthermore, it reduced the THD in balanced abnormal conditions by 0.5% for the two-level inverter and 0.18% for the three-level NPC inverters. However, the dq controller has a lower THD during unbalance and short circuit conditions.

New methods for proportional-integral controller design for time-delay systems

The development of structured methods for proportional-integral (PI) controller design for systems with time delay are proposed in this article. Several PI controller design methods for time-delay systems have been reported. However, combining two or more methods to form new ones have not been given serious attention. The system stability region in the controller parameters space was determined by plotting the stability boundaries. In this study, the controller gains were first obtained using genetic algorithm (GA), weighted geometric center (WGC), and centroid of convex stability region (CCSR). Thereafter, these gains were combined by finding the centroids of lines joining any of the two gain locations, and triangle whose vertices are the location of the three gains in the convex stability region, thus yielding four additional methods, M1, M2, M3, and M4. Compared to a particular existing method, some of the proposed methods yield faster response speed at the expense of reference input tracking, while the reverse is the case for others. Any of the proposed methods (M1, M2, M3, and M4) can be selected depending on the system performance specifications.

A New Parameter Tuning Technique for Noninteger Controllers in Low-Inertia Modern Power Grids

Since isolated microgrid systems are prone to unwanted frequency oscillations against load fluctuations and randomness of renewable sources, load frequency control (LFC) plays a vital role in restoring the frequency of such systems. In the microgrid with virtual inertias, the existing dynamic analysis of LFC assessment is not enough to meet the grid stability due to the virtual inertia control. Confronted with this problem, a noninteger (or fractional-order) type of proportional–integral controller design is developed in this work for LFC synthesis of the microgrid with the application of virtual inertia. In particular, a new analytical tuning scheme is adopted for the proper setting of the established noninteger controller to effectively damp the frequency oscillations of the concerned system under the virtual inertia. In the suggested analytical scheme, the stability boundary locus and geometric centroid methods are used to tune the coefficients of the noninteger LFC controller. The analysis of stability region curves has been conducted to study the dynamic effects of the virtual inertia and damping over the microgrid performance. Finally, the efficiency of the suggested noninteger controller design and accuracy of the stability analysis in regulating a microgrid with virtual inertia and damping are proved.

Centralized Proportional Integral Controller Design for the Activated Sludge Process

AbstractThe design of a centralized proportional integral controller for a single‐tank activated sludge process is presented. The relative normalized gain array (RNGA) and dynamic relative gain array (dRGA) were adopted for enhancing the closed‐loop performance of a multivariable system. The dRGA method gave superior and acceptable responses compared to the RNGA method. The designated error indices decreased significantly for the dRGA method compared with the RNGA method. The dRGA method is simple and effective, since it considers the process dynamics to provide an accurate interaction assessment. The designed centralized controller overcomes the limitations of the decoupler for stability challenges when compared with decentralized controllers.

Decentralised PI controller design based on dynamic interaction decoupling in the closed-loop behaviour of a flotation process

An enhanced method for design of decenralised proportional integral (PI) controllers to control various variables of flotation columns is proposed. These columns are multivariable processes characterised by multiple interacting manipulated and controlled variables. The control of more than one variable is not an easy problem to solve as a change in a specific manipulated variable affects more than one controlled variable. Paper proposes an improved method for design of decentralized PI controllers through the introduction of decoupling of the interconnected model of the process. Decoupling the system model has proven to be an effective strategy to reduce the influence of the interactions in the closed-loop control and consistently to keep the system stable. The mathematical derivations and the algorithm of the design procedure are described in detail. The behaviour and performance of the closed-loop systems without and with the application of the decoupling method was investigated and compared through simulations in MATLAB/Simulink. The results show that the decouplers - based closed-loop system has better performance than the closed-loop system without decouplers. The highest improvement (2 to 50 times) is in the steady-state error and 1.2 to 7 times in the settling and rising time. Controllers can easily be implemented.

Modeling and Optimal Control Applying the Flower Pollination Algorithm to Doubly Fed Induction Generators on a Wind Farm in a Hot Arid Climate

Abstract In the present paper, the flower pollination algorithm (FPA) is employed for tuning the controller parameters of a doubly fed induction generator (DFIG) in a wind energy system. These parameters are then compared with those generated by the genetic algorithm (GA) and the proportional-integral (PI) (initial design) controllers. Performance analysis of the DFIG is carried out in dynamic mode in two case studies. The first case study is carried out with no failure, the second one is subject to a short circuit in the electrical network. In this latter case study, a break occurs in the rotor circuit and disconnects the DFIG from the power grid. This gives rise to an excessive current in the rotor circuit which in turn influences the converters AC/DC/AC and makes the IGBT very sensitive. The GA and the FPA are used to tune the PI controllers with the purpose of improving the quality of a power supply should electrical disturbances occur. The results show that by applying an optimal PI controller design to a DFIG using the FPA the performance of the DFIG system can be improved in the event of disturbances. When the PI controller tuning using the GA and the initial control system design is compared with the DFIG using the optimized design, a significant decrease in the overshoot of the rotor current and the DC-link voltage is observed.

The proportional-integral controller design based on a Smith-like predictor for a class of high order systems

Heat transfer and fluid flow play important roles in industrial processes, especially in chemical and thermal processes. Their dynamics are often modelled as high order systems with the type of [Formula: see text], which have slow responses to the set point and the input disturbance. To enhance the tracking and disturbance rejection performance of these systems, a control structure combining the proportional-integral (PI) controller and Smith-like predictor is proposed in this paper. The tracking and disturbance rejection performance of the proposed control structure with the order mismatch are analyzed. In addition, the precondition where the proposed control structure can obtain satisfactory disturbance rejection performance is deduced. By analyzing the influence of PI parameters on control performance, an empirical tuning rule, which can balance the control performance and robustness constraint well, is summarized and the corresponding tuning toolbox is developed. Finally, the superiority of the proposed control structure is verified by simulations and comparative experiments based on Peltier temperature control platform.

Analysis and Design of a Double Fuzzy PI Controller of a Voltage Outer Loop in a Reversible Three-Phase PWM Converter

Aiming at the application of a reversible three-phase pulse width modulation (PWM) converter with a wide range of AC side voltage and DC side voltage, a double fuzzy proportional integral (PI) controller for voltage outer loop was proposed. The structures of the proposed controller were motivated by the problems that either the traditional PI controller or single fuzzy PI controller cannot achieve high performance in a wide range of AC and DC voltage conditions. The presented double fuzzy controller studied in this paper is a sub fuzzy controller in addition to the traditional fuzzy PI controller; in particular, the sub fuzzy controller can get the auxiliary correction of PI control parameters according to the AC side voltage and the DC side given voltage variation of PWM converter after the reasoning of the sub fuzzy controller, while the traditional fuzzy PI controller outputs the correction of PI control parameters according to the DC voltage error and its error change rate. In this paper, the traditional fuzzy PI controller can be called the main fuzzy controller, and the adaptive adjustment of PI control parameters of the voltage outer loop is the sum of the PI parameter correction output by the main fuzzy controller and the auxiliary PI parameter correction output by the sub fuzzy controller. Finally, the experimental results show that the reversible three-phase PWM converter can achieve excellent dynamic and static performance in a wide range of AC voltage and DC voltage applications by using the proposed double fuzzy PI controller.

Small Signal Modeling and Decoupled Controller Design for a Triple Active Bridge Multiport DC–DC Converter

This article proposes modeling and two controller design techniques for a triple active bridge (TAB) three-port dc-dc converter comprising of fuel cell, battery, and load. The sources are integrated, employing boost interleaved full-bridge converters in order to get smoother source current profile. The converter is a nonlinear multi-input multi-output (MIMO) system with a large number of control variables. Moreover, a high degree of coupling among the control variables makes its modeling and control system design quite cumbersome and complex. To overcome the complexity of analysis in a higher order system like TAB, a generalized frequency-domain modeling technique is introduced in this article. A new decoupling matrix-based proportional-integral controller design method is also proposed. It reduces the design complexity and improves the system dynamic performance (lower settling time, overshoot/undershoot in the controlled variables) in comparison to similar three-port converters reported in the literature. Further, the performance of the proposed controller is compared by simulation with another popular MIMO system controller design technique, namely the state feedback control. A 1-kW laboratory prototype is built and tested to verify the system performance during dynamic load changes, source current variation, and battery charging/discharging operation.

Robust decentralized proportional–integral controller design for an activated sludge process

AbstractThis paper presents the design of a decentralized proportional–integral (PI) controller for a wastewater treatment plant (WWTP). The aeration rate and the return recycle sludge rate are manipulated inputs to the WWTP process, while substrate and biomass concentration are considered as the output variables. The study is divided into two segments: A decentralized controller is designed based on the best pairing in the first segment, and in the second segment, a decoupler is developed to reduce the interactions. Decouplers are generally used to create independent loops in the multivariable control loops. Each decoupled subsystem is converted to first order plus time delay (FOPTD) model using a system identification toolbox to design independent diagonal controllers. The numerical simulations have been performed to evaluate the effectiveness of the presented methods. Furthermore, a robustness study has also been carried out by taking into account multiplicative input and output uncertainties, and it is found that the controller designed based on minimizing the integral of absolute error (IAE) criteria shows more robust.

Design of PI Controllers for Irrigation Canals Based on Linear Matrix Inequalities

A new Proportional-Integral (PI) tuning method based on Linear Matrix Inequalities (LMIs) is presented. In particular, an LMI-based optimal control problem is solved to obtain a sparse feedback that provides the PI tuning. The ASCE Test Canal 1 is used as a case study. Using a linearised model of the canal, different tunings for the design of the PI controller are developed and tested using the software Sobek. Furthermore, the proposed method is also compared with other tunings proposed for the same canal available in the literature. Our results show that the proposed method reduces by half the maximum errors with respect to other assessed alternatives and minimizes undesired mutual interactions between canal pools. Also, our method improves the optimality degree of the PI tuning by 30%. Therefore, it is concluded that the LMI based PI controllers lead to satisfactory performance in regulating water levels and canal flows/structure outflows, outperforming other tested alternatives, thus becoming a useful tool for irrigation canal control.