An optimal control of Reverse Osmosis (RO) plant is studied in this paper utilizing the auto tuning concept in conjunction with PID controller. A control scheme composing an auto tuning stochastic technique based on an improved Genetic Algorithm (GA) is proposed. For better evaluation of the process in GA, objective function defined newly in sense of root mean square error has been used. Also in order to achieve better performance of GA, more pureness and longer period of random number generation in operation are sought. The main improvement is made by replacing the uniform distribution random number generator in conventional GA technique to newly designed hybrid random generator composed of Cauchy distribution and linear congruential generator, which provides independent and different random numbers at each individual steps in Genetic operation. The performance of newly proposed GA tuned controller is compared with those of conventional ones via simulation. Keywords—Genetic Algorithm, Auto tuning, Hybrid random number generator, Reverse Osmosis, PID controller.

Auto Tuning PID Controller based on Improved Genetic Algorithm for Reverse Osmosis Plant

This paper presents both offline and online optimization techniques for the control of a multiple high voltage direct current link power system. A frequency control scheme based on classical proportional-integral-derivative controllers is proposed and optimally tuned offline using particle swarm optimization. The performance of this scheme is compared with the performance of a centralized model predictive control (MPC) scheme, and a distributed MPC scheme that uses only local communications. The results illustrate that a significant performance improvement can be achieved using distributed MPC instead of classical control, illustrating the potential of distributed MPC for use in future power networks.

Optimal Coordination of a Multiple HVDC Link System Using Centralized and Distributed Control

In this paper, model based design of PID controllers is proposed for higher-order oscillatory systems. The proposed method has no limitations regarding systems order, time delays and oscillatory behavior. The reduced model is achieved based on third-order modeling and selection of coefficients through the use of frequency responses. The tuning of the PID parameters are obtained from a reduced third-order model; the procedure seems to be simple and effective, and improved performance of the overall system can be achieved. Three simulation examples and one real-time experiment are included to demonstrate the effectiveness and applicability of the proposed method to systems with oscillatory behavior.

Tuning PID controllers for higher-order oscillatory systems with improved performance.

A novel cost-effective and high-efficiency single-switch resonant inverter with a power-factor-correction (PFC) scheme is proposed to drive a piezoelectric ceramic transducer (PCT) for an ultrasonic cleaner. The circuit topology is derived by integrating a flyback converter that served as the PFC stage with a Class E resonant inverter for driving a thin PCT at its resonance frequency. A unity power factor is achieved by operating the flyback converter in discontinuous conduction mode. With tactfully designed circuit parameters, the Class E resonant inverter is operated at the suboptimum mode to minimize switching losses of the active switch, leading to a high circuit efficiency. The active switch is controlled by pulsewidth modulation at a fixed switching frequency and a constant duty ratio to adjust the output power of the PCT. The operation modes, design equations, and steps for the circuit parameters are proposed. A prototype circuit designed for a 42-W ultrasonic cleaner was built and tested to verify the analytical predictions. Satisfactory performances are obtained from the experimental results.

Single-Switch High-Power-Factor Inverter Driving Piezoelectric Ceramic Transducer for Ultrasonic Cleaner

— This paper deals speed control of a DC motor using fractional-order control. Fractional calculus provides novel and higher performance extensions for fractional order proportional integral and derivative (FOPID) controller. In this paper, the parameters of the FOPID controller are optimally learned by using Genetic Algorithm (GA), and the optimization performance target is chosen as the integral of the absolute error (IAE). Simulation results show that the FOPID controller performs better than the integer order PID controller.

Fractional-Order PID Controller Design for Speed Control of DC Motor

In this paper we uses a software pack, which allows to adjust PID controller automatically in real time way in the case of changes parameters of used object. PID settings are optimized in real time by using genetic algorithm and are compared with generally accepted quality indicators for control systems like rise time, % overshoot and settling time of step response or such coefficient like oscillations frequency, reduced damping and gain of second order object. A digital signal processor (DSP) is a specialized microprocessor designed specifically for digital signal processing generally in real time applications requiring high computation. The simulation results were verified by some laboratory test.

On-line PID controller tuning using genetic algorithm and DSP PC board

In this paper the genetic algorithm is used to optimization of parameters the equivalent electrical circuit of piezoelectric ceramic. Sandwich type piezoelectric ceramic transducer are the source of power ultrasounds when the vibration is activated by a voltage inverter. The output frequency of inverter most by equals the mechanical resonance frequency of the transducer and most by tuning with very high precise. In real circuits the mechanical resonant frequency is function of many parameters of piezoelectric material. The equivalent electrical circuit of transducer transforms this parameters in electrical value. This electrical circuit consist of connection in parallel: Co end RLC elements and this units are part of the oscillating circuit of inverter. The values of equivalent electrical circuit varies during the operation of transducer in function extending parameters, among others, the most important are temperature and time. In this situation to obtain the optimal value of the output voltage frequency of inverter most by know electrical parameters equivalent circuit of transducer. In the resolution of difficult problems to by effective the genetic algorithm.

Genetic identification of parameters the sandwich piezoelectric ceramic transducers for ultrasonic systems

This paper deals with fuzzy logic control of inverter fed synchronous motor. In this paper mathematical model of the motor drive system and stability condition of fuzzy logic control algorithm are represented. The essential fuzzy logic control configuration system consists of an internal current regulation loop and an external speed regulation loop. PID controller generally controls the speed and current loop in these systems. To control a inverter fed synchronous machine a host computer and a special microprocessor system with dSPACE 1104 central unit as a microcontroller is used. Most important results of our investigation is to find a simply mathematical model of our motor drive system. Then stability conditions are determined for current and speed controller. The simulated results were compared during the laboratory test on 600 W synchronous motor.

R. Lagoda

Papers

On-line PID controller tuning using genetic algorithm and DSP PC board

Genetic identification of parameters the sandwich piezoelectric ceramic transducers for ultrasonic systems

A very simple fuzzy control system for inverter fed synhronous motor