Adaptive Hysteresis Controller Research Articles

Enhancement in fault ride through capabilities with inertia control for DFIG-wind energy conversion system

Doubly fed induction generator (DFIG)–based wind energy conversion system (WECS) has been found very effective in harnessing wind power. Conferring to grid code requirements, DFIG needs to stay connected to the grid under fault conditions. This implicates the requirement of enhancing the transient stability through augmenting the low-voltage ride through (LVRT) capability of DFIG. There are many software and hardware solutions for the improvement of LVRT. Fault current limiter is one of the frequently used hardware solutions for the argumentation of fault ride through requirements. Instead of LVRT, DFIG-based WECS also faces low inertia problems at fault condition. In this article, a combined approach of virtual inertia control with an external retrofit adaptive hysteresis control–based bridge-type fault current limiter (AHC-BFCL) is proposed to improve the LVRT capability as well as the inertia of DFIG-WECS. The results are compared with that of a conventional logic control-BFCL and proportional–integral-BFCL.

Theoretical Foundations Development of Space Adaptive Video Information Systems Synthesis

The main provisions and principles of the synthesis of adaptive video information systems designed for recording and analyzing images of dynamic scenes at the stages of long-range detection of artificial space objects, ballistic and controlled approach to them in the middle and near zone of cooperation are considered. Based on the principle of dominant information, it is shown that the basis for the development of methods and algorithms for processing video information in on-board surveillance systems is the joint adaptive processing of video information in photo-detector matrices and in digital processors in order to maximize the quality of information issued to the consumer by suppressing background and noise information by adaptive hysteresis control of the frame frequency, frame resolution and signal accumulation time in the photodetector matrix, as well as the use of parametric neural network detectors-classifiers.

Novel Adaptive Hysteresis Regime and Data Fusion on Crisp Logic in IoT-based Terrarium System for Improving Plant Growth Rate

In the present, autonomous environmental supervision and management are still insufficient. The approach of independent parameter controlling emerges to restraining plant growth and resource inefficiency. Developing a new method to control environmental parameters for accelerating plant growth should be deployed to satisfy the optimum condition and resource efficiency. In this paper, we propose a novel advanced crisp logic-based integrated with adaptive hysteresis control and data fusion algorithm to adapt the behaviour of each plant parameter in a certain condition. The objective of the proposed system is to control each plant parameter into the optimum regime while considering the coupling relationship between them. The measurement results show that our proposed system has a more sustained optimum condition and faster change into the desired grade of membership by adapting the hysteresis regime. Based on the measurements, the proposed system produces an optimum condition that are more sustain and stable and produce accelerated plant growth by 35.33%.

Energy efficient control of a stand-alone wind energy conversion system with AC current harmonics compensation

This paper presents a new energy-efficient control strategy for a variable-speed wind energy conversion system (WECS). The considered WECS is designed for dc load supply and battery charging in stand-alone applications. The batteries are charged through a three-phase full-bridge power converter. The WECS contains a vector-controlled self-excited induction generator (SEIG) coupled to a wind turbine (WT) for electric power generation on the ac side. The control algorithm proposed in this paper includes three separate optimizations: two fuzzy-logic-based optimizations, which ensure that maximum energy is extracted from both the WT and the SEIG, respectively, at all operating conditions, and also the optimization of phase current harmonics through adaptive hysteresis control. In addition, a recently developed algorithm for real-time loss calculation of a hysteresis-driven power converter is utilized to quantitatively assess the power converter losses with respect to different hysteresis bandwidth settings. The performance of the proposed control algorithm is experimentally evaluated and compared with two competing algorithms which do not involve current harmonics compensation, whereas one of them also does not involve optimization of the SEIG output power. This enables evaluation of the gain in system performance due to the introduced optimizations. The evaluation and comparison are made over a wide range of wind speeds, both in steady state and under transient conditions, by using a 1.5 kW experimental setup with the DS1103 controller board (dSPACE).

A Fuzzy adaptive hysteresis band controller for three phase four wire UPQC

Unified Power Quality Compensator (UPQC) is used to protect the sensitive loads in the distribution system from voltage and current disturbances. The compensation capability of UPQC depends on the control strategies used for shunt and series converters. Conventional adaptive hysteresis controller pulse width modulation technique had failed to track exactly during transient conditions and disturbances at load and source side. In paper fuzzy adaptive hysteresis controller is proposed for three phase four wire UPQC for compensating voltage sag/swell, current harmonics, voltage harmonics and neutral current compensation. Fuzzy adaptive hysteresis controller can effectively compensate the power quality problems during the transient conditions. A comparative simulation analysis of proposed and conventional methods are presented in this paper using MATLAB/SIMULINK tool.

An adaptive deep-coupled GNSS/INS navigation system with hybrid pre-filter processing

The deep-coupling of a global navigation satellite system (GNSS) with an inertial navigation system (INS) can provide accurate and reliable navigation information. There are several kinds of deeply-coupled structures. These can be divided mainly into coherent and non-coherent pre-filter based structures, which have their own strong advantages and disadvantages, especially in accuracy and robustness. In this paper, the existing pre-filters of the deeply-coupled structures are analyzed and modified to improve them firstly. Then, an adaptive GNSS/INS deeply-coupled algorithm with hybrid pre-filters processing is proposed to combine the advantages of coherent and non-coherent structures. An adaptive hysteresis controller is designed to implement the hybrid pre-filters processing strategy. The simulation and vehicle test results show that the adaptive deeply-coupled algorithm with hybrid pre-filters processing can effectively improve navigation accuracy and robustness, especially in a GNSS-challenged environment.

Robust Energy Management of a Hybrid Wind and Flywheel Energy Storage System Considering Flywheel Power Losses Minimization and Grid-Code Constraints

The maximum power and power ramp rate are important grid codes for integrating renewable energy resources in transmission systems. The power curtailment regulates the maximum power and ramp rate; however, adding an energy storage system (ESS) can time shift surplus wind energy instead of curtailing it. The flywheel energy storage system (FESS) has the advantages of high efficiency and long lifetime; however, it has non-negligible standby losses and its lifetime is reduced exponentially as the rotating speed increases. Considering such practical constraints, this work presents an energy management system (EMS) for a hybrid power system composed of a wind farm with a FESS. The FESS time shifts the surplus wind energy to respect the grid codes and reduce wind curtailment; meanwhile, the EMS aims at minimizing the FESS standby losses and boosting its lifetime using the predicted wind power data. The EMS is composed of two controllers. The first controller is a linear model predictive controller that defines the long-term FESS power set-point. The second controller is a real-time adaptive hysteresis controller that compensates for the wind-power prediction error. Comparative simulation studies and hardware-in-the-loop test results validate the effectiveness of the proposed EMS in reducing the FESS losses while respecting the grid integration code constraints.

Enhancement of Power Quality with Shunt Active Power Filter using Fuzzy Adaptive Hysteresis Controller

Enhancement of Power Quality with Shunt Active Power Filter using Fuzzy Adaptive Hysteresis Controller

Power quality problem mitigation by unified power quality conditioner: an adaptive hysteresis control technique

An adaptive hysteresis current and voltage control technique for controlling Unified Power Quality Conditioner (UPQC) is proposed in this paper. The novelty of the proposed method is the series and shunt active power filters (APF) present in the UPQC has been controlled by the separate adaptive controllers for reducing the voltage and current perturbations. Here, the adaptive control technique utilises Artificial Neural Network (ANN) and Fuzzy Logic Controller (FLC) for generating the control pulses of the series and shunt APFs. In the adaptive control technique, ANN builds a target hysteresis control data based on the inputs such as voltage and current. By using the hysteresis control data, the control parameters are generated by the FLC. According to the output of FLC, PWM pulses are generated for controlling the APFs. The effectiveness of the proposed adaptive hysteresis control technique is identified by using the comparison analysis with the existing techniques.

A fixed-frequency fast transient response DC–DC controller for VRMs

A 2V-10A fast transient response DC–DC buck controller based on fixed frequency hysteresis control is presented. A carefully designed output voltage filter detects the output capacitor current change which helps the controller to respond immediately after load changes. Adaptive hysteresis control guarantees the switching frequency to be the same as the reference frequency by using a CCII-composed circuit and current mirrors. The controller is designed and fabricated in a TSMC 0.35 μm process. Simulation and test results show that this controller achieves a 20 μs settling time in one single switching cycle when load current changes from 1 A to the full load condition at 10 A.

Reactive Power Compensation in Inverter Interfaced Distributed Generation

The consumption of reactive power is stochastic in nature for the distribution system. This uncertain variation of the reactive power leads to 1) Variation of voltage at the point of common coupling(PCC) 2)Low power factor 3)low efficiency 4) improper utilization of distribution system and 5) loss of synchronism for a grid connected inverter based – distributed generation. Now a day’s distributed generation (DG) system uses current regulated PWM voltage-source inverters (VSI) for synchronizing the utility grid with DG source in order to ensure the grid stability. In this paper reactive power compensation based hysteresis controller and adaptive hysteresis controller is analyzed for inverter interfaced DG which can control the active and reactive power independently. The adaptive hysteresis controller can reduce the current harmonic at PCC considerably which ensures lower total harmonic distortion (THD). The performance indices include THD of the grid current, fast current tracking during steady state and transient conditions. The studied system is modeled and simulated in the MATLAB Simulink environment.

An Adaptive Hysteresis Band Controller for Single Phase PV Inverters

Hysteresis current controllers are widely used in PV inverters. The main drawback of conventional hysteresis current control is that the switching frequency is variable, as the hysteresis band is fixed. In this paper an adaptive band hysteresis control algorithm with no derivative calculation is presented. As it will be shown, this algorithm can limit the switching frequency variation within a small range and the algorithm itself is simple and easy to be implemented. The performance of this algorithm, together with the one [10] and conventional hysteresis control has been evaluated by means of simulations performed with PSIM and SIMULINK. Simulation results show the effectiveness of the suggested hysteresis current controller.

A Novel Fuzzy—Adaptive Hysteresis Controller Based Three Phase Four Wire-Four Leg Shunt Active Filter for Harmonic and Reactive Power Compensation

This paper presents a fuzzy logic based three phase four wire four-leg shunt active power filter to suppress harmonic currents. Modified instantaneous p-q theory is adopted for calculating the compensating current. Fuzzy-adaptive hysteresis band technique is applied for the current control to derive the switching signals for the voltage source inverter. A fuzzy logic controller is developed to control the voltage of the DC capacitor. Computer simulations are carried out on a sample power system to demonstrate the suitability of the proposed control strategy, for harmonic reduction under three different conditions namely, ideal, unbalance, unbalance and distorted source voltage conditions. The proposed control strategy is found to be effective to reduce the harmonics and compensate reactive power and neutral current and balance load currents under ideal and non-ideal source voltage conditions.