Double Closed-loop Research Articles

Control Strategy for Boost Converter based on Passive Sliding Control Mode

Passive sliding mode control strategy is designed based on passive control with energyshaping and damping injection for Boost converter. The control structure has double close loops. The expected output current is determined by sliding mode controller in outer voltage loop and the switch function control is determined by passive control in inner current loop. Simulation results reveal that the passive sliding mode control strategy has good dynamic and static performances and anti-disturbance ability.

Study on Speed Control Strategy of Brushless DC Motors Based on Fuzzy PID

Firstly, this article establishes the mathematical models and speed principles of brushless DC motors. Next, it designs fuzzy PID controllers and current adjustors based on the adjusting speed theory and characteristics of brushless DC motors, which form double closed-loops to achieve intellectualized adjustment of brushless DC motors, creating the best effects simultaneously.

Iterative Learning Double Closed-Loop Structure for Modeling and Controller Design of Output StochAstic Distribution Control Systems

Stochastic distribution control (SDC) systems are known to have the 2-D characteristics regarding time and probability space of a random variables, respectively. A double closed-loop structure, which includes iterative learning modeling (ILM) and iterative learning control (ILC), is proposed for non-Gaussian SDC systems. The ILM is arranged in the outer loop, which takes a longer period for each cycle termed as a BATCH. Each BATCH is divided into a modeling period and a number of control intervals, called batches, being arranged in the inner loop for ILC. The output probability density functions (PDFs) of the system are approximated by a radial basis function neural network (RBFNN) model, whose parameters are updated via ILM in each BATCH. Based on the RBFNN approximation of the output PDF, a state-space model is constructed by employing the subspace parameter estimation method. An IL optimal controller is then designed by decreasing the PDF tracking errors from batch to batch. Model simulations are carried out on a forth-order numerical example to examine the effectiveness of the proposed algorithm. To further assess its application feasibility, a flame shape distribution control simulation platform for a combustion process in a coal-fired gate boiler system is constructed by integrating WinCC interface, MATLAB simulation programs, and OPC communication together. The simulation study over this industrial simulation platform shows that the output PDF tracking performance can be efficiently achieved by this double closed-loop iterative learning strategy.

Simulation and Analysis of Rectifier Circuit Based on Double Closed-Loop Vector Control Method

Pulse width modulation (PWM) technology based on rotating coordinate transform is a new type of rectifier control method. Through the electromagnetic transient process of the analysis of the rectifier circuit we can verify the accuracy of this control method. Therefore, this paper first analyzed electromagnetic transient process of the rectifier circuit. By changing the phase and amplitude of voltage to realize the active and reactive power decoupling control independently. Than,it built the simulation model of rectifier circuit with the electromagnetic transient analysis software PSCAD. This cricuit is controlled by PWM based on double closed-loop vector. The simulation and analysis of the circuit are performed on the basis of the model. The simulation results can reflect the electromagnetic transient process of the circuit accurately,so as to verify the correctness of the proposed control method to control the rectifier circuit.

A new digital control system based on the double closed-loop for the full-bridge inverter

The control system based on the primary current feedback mode can effectively suppress the magnetic bias and avoid the overcurrent for the full bridge inverter. But in the process of its digitalization, the magnetic bias signal can be missed easily and the control accuracy is low, resulting in poor system stability and reliability. First, a new double closed-loop digital control method is proposed, which has advantages of the magnetic bias suppression in the primary current feedback mode and fast fine current adjustment in the secondary current feedback mode. Second, results of theoretical analysis on system stability and simulation prove that the method is feasible. Third, a single-chip design idea based on analog-digital mixed field-programmable gate array (FPGA) is proposed, and the detailed design program is described for the submerged arc welding system, which has high integration and strong anti-interference. Experimental results show that the digital control system has high stability and reliability to produce high submerged arc welding quality.

10KW/100KHZ High Frequency Induction Heating Power Supply Design

TMS320F2812 was taken as the main controlling chip, MOSFET was taken as the inverter switching device and IGBT was taken as the chopper switching device in the system. This paper introduced the main topology circuit design and circuit components selection.In the process of heating, double-closed loop control strategy fuzzy and DPLL (Digital Phase Locked Loop) was adopted. The simulation model of induction heating power system was built in SIMULINK platform. The simulation results indicate that the load frequency automatic tracking and closed-loop power control are realized. The time to steady output is about 0.1ms. Finally, built the 10kW/100kHZ induction heating power supply experimental platform, As can be seen from the experimental waveforms, the equivalent impedance of the load can always be weakly perceptual state.

The Design of Digital Medium Frequency Induction Heating Power Supply Based on DSP and FPGA

DSP (XC2267) is the main control chip which does the increment PI algorithms and realizes the voltage and current double closed-loop. Three-phase thyristor rectifier method based on the phase self-adjusting of FPGA is proposed. A method for swept-frequency start circuit is designed to implement the transition between the high-power and low-power. The invert system uses the compound control of improved PWM and frequency phase lock to improve the control accuracy and efficiency. Lastly, by using bench, the circuit is tested and the feasibility and effectiveness of the whole system are verified.

Grid-Connected Control Strategy Based on Fixed Mi Coefficient for Single-Phase Photovoltaic System

This paper presents a grid-connected control strategy for single-phase photovoltaic (PV) system. Voltage source inverter (VSI) of a PV system is a core component which will produce some harmonics when the switch is operated between on and off continuously. To suppress harmonic distortion in the VSI output current, a fixed modulation index (MI) control loop based on PI controller is added to the traditional double closed-loop. The proposed method can fix the MI coefficient to be a large value in any conditions. The design of the controller and the stability of the grid-connected system are discussed in detail. Simulation and experiment results are presented to demonstrate the dynamic and precision performance of the controller for harmonic suppression when the proposed PV system is connected to the grid.

Improved Direct Torque Double Closed-Loop Control Algorithm for Induction Motor

This paper presents an improved direct torque control (DTC) algorithm as compared to a traditional DTC scheme. In the traditional scheme, a pair of hysteresis comparators is used to control motor stator flux and electromagnetic torque. This causes a variable switching frequency which results in a high flux and torque ripples. To mitigate these issues, an improved DTC algorithm based on a double closed-loop is presented. Acting the induction motor as a control object, a mathematical model of the flux and torque based on proportional and integral (PI) controller in the double closed-loop is established. With the flux and the torque treated as control variables, a smooth and continuous vector control and a fast-response DTC are observed. By adopting this improved DTC algorithm, the simulation and experimental results indicate that the flux and the torque ripples reduced greatly. Additionally, the static and dynamic performances of the system are improved because of the mentioned scheme operating at a constant switching frequency. DOI : http://dx.doi.org/10.11591/telkomnika.v12i2.4329

Research on Control Strategy of PV MPPT and Grid-Connected Single Phase Converter Based on Two Stage Topology

This paper studied the control strategy of single-phase two-stage grid-connected photovoltaic generation system. The two-stage topology includes the boost converter and single phase inverter. The function of maximum power point tracking (MPPT) is achieved in the boost circuit by IC (Increment Conductance) method. The inverter circuit adopted the double-closed loop control, a DC voltage outer loop control for power balance with PI correction and an AC current inner loop control for feedback designed to ensure the current quality and stabilize the DC voltage. The inner loop used the novel quasi-Proportional-Resonant (PR) controller, which has a better steady tracking characteristics and stronger anti-interference ability to the disturbance. Finally, a simulation system is built with Matlab/Simulink in this paper to verify the validity of the MPPT algorithm and the quasi-PR control strategy.Keywords：Photovoltaic Generation System;Maximum Power Point Tracking; Grid-connected Inverter; quasi-Proportional-Resonant (PR) controller

Modeling and Simulation of BLDCM Double Closed-Loop Control System Based on Matlab

Based on the mathematical model of brushless DC motor, a simulation model of brushless DC motor (BLDCM) double closed-loop control system is established by using the voltage equation, the electromagnetic torque equation and the motion equation based on Matlab, then introduces the sub-modules of the controlling system in detail. PID control is used in the speed loop and hysteresis current track of PWM is used in the current loop. The reasonability and validity are testified by the simulation results and this novel method offers a new thought way for designing and debugging actual motors.

Brushless DC Motor Controller Design and Double-Loop PID Parameter Tuning

An efficient and practical controller was designed, which achieves high performance for a BLDC motor. Actual hardware experimental platform was established. Double-closed loop control scheme using PID algorithm is presented and applied into the system successfully. Through the tuning of PID parameters, the start and stop of motor is fast, current fluctuation is small, and the actual speed of operation is consistent to the set speed, the error of stability maintains at 10r/min or less. The experiment result shows the BLDC control system operates smoothly, and it has high reliability, robustness.

Design and Implementation of an Optimized Double Closed-Loop Control System for MEMS Vibratory Gyroscope

This paper describes the development and experimental evaluation of a microelectromechanical system vibratory gyroscope using an optimized double closed-loop control strategy. An automatic gain control self-oscillation interface is used to resonate the gyroscope in the drive mode; the sense mode is controlled by a sixth-order continuous-time and force-feedback band-pass sigma-delta modulator. The parameters of both control loops are optimized by a genetic algorithm (GA). System level simulations show that the settling time of the drive mode self-oscillation is 125 ms, the root mean square displacement of the proof mass is in the sense mode, and the signal-to-noise ratio is 90 dB in a bandwidth of 64 Hz with a 200 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> /s angular rate input signal. The system is implemented using symmetrical and fully decoupled silicon on insulator gyroscope operating at atmospheric with the circuit implemented on printed circuit board. The measured power spectral density of the output bitstream shows an obvious band-pass noise shaping and a deep notch at the gyroscope resonant frequency. The measured noise floor is approximately -120 dBV/Hz <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1/2</sup> . In the drive mode, the relative drift of the resonant frequency and amplitude is 3.2 and 10.7 ppm for 1 h measurements, respectively. The settling time, scale factor, zero bias stability, and bandwidth of the gyroscope controlled by the optimized control system are 200 ms, 22.5 mV/ <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> /s, 34 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> /h, and 110 Hz, respectively. This is compared with a non-optimized system for which the corresponding values are 300 ms, 17.3 mV/ <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> /s, 58 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> /h, and 98 Hz; hence, by GA optimization a considerable performance improvement is achieved.

Research on Double Closed-Loop DC Speed-Regulation System Based on Improved Particle Swarm Optimization

For the defects of the parameter tuning and optimization of the PID controller uses an improved Particle Swarm Optimization (IPSO) algorithm to apply on the dual closedloop DC speed tuning system and adjust PID controller parameters online. The optimization result of adopting step response of the improved PSO algorithm is analyzed. It shows that using the improved PSO algorithm will obtain better dynamic performance, follow faster and more robustness than the traditional engineering design method. It provides a good performance of practical method for PID parameters optimization.

Research on the Control Method of STATCOM Based on MMC

To realize the STATCOM based on Modular Multilevel Converter (MMC), a simplified double-closed loop structure, simplifying from the control method of High Voltage Direct Current (HVDC) based on MMC, is presented. Considering MMCs DC side using capacitors, a part-controlling method based on energy balancing is proposed, to solve the voltage balancing problem. With the part-controlling fixing the changing capacitors voltage and the simplified double-closed loop control method, voltage fluctuation could be reduced, and the loads reactive power could be compensated. The correctness and the effectiveness of the MMC-STATCOM controlling scheme is verified by Matlab/Simulink.

Double Closed-Loop Control of the Three-Level Rectifier Based on Synchronous PI Current Decoupling

This paper analyzes the mathematical model of the three-level PWM rectifier in the three-phase stationary coordinate system and the two-phase synchronous rotating coordinate system. On this basis, the synchronous PI current double closed-loop decoupling control strategy is used to eliminate the impact between the d-q axis and relieve independent control of two axes. In order to simplify the complexity of the vector synthesis, the three-level space vector modulation (SVPWM) algorithm is studied. Transform the three-level space reference vector synthesis to the two-level. The mathematical model of the theoretical analysis are verified with Matlab/Simulink. The simulation result demonstrates that the design method is reasonable and effective, which makes the PWM rectifier excellent dynamic and static performance.

Electric Hydraulic Power Steering System Simulation Study

Properly controlling electro hydraulic power steering system can improve steering performance. The relation of motor speed, vehicle speed and steering speed is gained, according to the influence of motor speed on the steering performance. The force and angle input is set in the driver input model. Rotary valve is simulated by four orifices. The steering resistance between tire and ground is simulated by the coulomb friction on two tips of the rack. The method of double closed-loops PID is used to control the motor. The influence of the control strategy on the steering performance is realized by the simulations of three typical situation, which includes steering portability, road feel, the speed of assist force response and its stability. The results of simulation validate the availability of the control strategy, which is the basic of optimization.

Design and Simulation of Fuzzy-PID DC Governor System Based on Mine Hoist

According to the requirement of smooth operation and accurate positioning for DC speed regulating system of mine hoist, a new speed control system that based on double closed-loop of Fuzzy-PID was designed. The best control scheme for mine hoist was also validated by simulation comparison with conventional PID control system in the MATLAB/Simulink. The result showed that the proposal was feasible and had practical value.

Modeling and Simulation of PWM Converter Based on the PID Neural Network

The Phase shifted Full-bridge Zero-voltage Zero-current-switching Pulse-Width Modulation (PS-FB-ZVZCS-PWM) converter is discussed in this paper and the PID neural network is used to be the dual loop controller of the system. The results of the simulation prove that the PID neural network double close loop system has achieved the nice control characteristics which are no overshoot, no static error, fast response, short transition time, good tracking performance.

Influence of Repetitive PI-P Control on Performance of Inverters Wireless Parallel System

For wireless parallel inverters system, there is a high requirement of control precision: otherwise current-sharing effect would be very poor. Based on this characteristic of wireless paralleling technology, this paper represents the combination control method of repetitive control with PI-P voltage and current double close loop control (abbreviation as PI control) in this system. This control method, which combines with PI control, has relatively faster dynamic response speed, improves not only the capacity with nonlinear load and parallel circulation characteristics by characteristics of repetitive control, but also the steady state control accuracy of the system, meanwhile reduces the harmonic content. Its an outstanding composite control method. This paper proves the feasibility and superiority of this method by MATLAB simulation.