Current Control Research Articles

Hysteresis Current Control for Six-Phase Induction Motor Drives With Reduced Ripple and Improved Tracking Based on Subspace Decomposition and Restrained Voltage Vectors

Hysteresis Current Control for Six-Phase Induction Motor Drives With Reduced Ripple and Improved Tracking Based on Subspace Decomposition and Restrained Voltage Vectors

Tecuide. Telemonitorización de pacientes con deterioro cognitivo y sus cuidadores

IntroductionGiven the growing increase in dementia, the need to control these patients, together with the rise of new technologies, makes a change in the current control system imperative. Material and methodWe have carried out a single-center, clinical study with two groups, a control group of 72 patients/caregivers, who followed the usual controls in consultations, and another telematic group of 76 patients/caregivers, who followed the controls through of the Tecuide platform. The platform had a survey part to detect problems in patients and caregiver claudication, another training part and another chat for direct communication when the caregiver needed it and also served to respond when a problem was detected. ResultsAfter a year of monitoring with the platform we have obtained: a)in patients, reduce behavioral disorders and use of drugs, increase physical exercise and delay institutionalization (DS not found); b)in caregivers there is an improvement in satisfaction with respect to the control of patients with cognitive impairment, and c)in terms of resources, visits to emergency services and dementia consultations have decreased, although admissions to the psychogeriatric unit have increased. ConclusionsThe use of Tecuide as a telematic tool in the control of patients with cognitive impairment does not seem to be inferior to the usual controls in consultations and improves caregiver satisfaction.

Model-Free Predictive Current Control Using Extended Affine Ultralocal for PMSM Drives

Model-Free Predictive Current Control Using Extended Affine Ultralocal for PMSM Drives

A Simplified Model Predictive Current Control Strategy for Six-phase H-bridge Inverters

Background: The double-end H-bridge inverters can realize independent control of the stator voltage in each phase and have flexible advantages of modulation and fault tolerance; thus, they are more suitable for multi-phase fault-tolerant motor drives. However, due to the increase of voltage vectors and the coupling between the electromagnetic and non-electromagnetic quantities, the normal control strategies for traditional three-phase motor drives do not work anymore. Objective: This paper aimed to propose a simplified model predictive current control strategy based on the vector space decomposition (VSD) and the vectors’ gradual simplification for the three-level six-phase H-bridge inverters. Methods: Firstly, the 729 physical variables were decomposed and mapped onto the fundamental αβ subspace, harmonic xy subspace, and the zero-sequence o1o2 subspace based on the VSD. Then, to eliminate the influence of the harmonic and zero-sequence components on the control performance and make an easy digital implementation, vectors’ simplification has been proposed based on the in-depth analysis of the relationship between the voltage vectors mapped onto different subspaces and vectors’ stratification. With the simplification method, the number of voltage vectors was simplified from 729 to 12, and then the selected voltage vectors were used in the rolling optimization of the model predictive current control (MPCC) to choose the optimal one. Finally, sufficient experiments were carried out including static and dynamic conditions, different modulation index and power factor, etc., to verify the feasibility of the proposed strategy. Results: The simulation and experimental results show that with the simplified MPCC strategy, both the static and dynamic performances are relatively good, and the THDs of the phase current under different modulations and power factors are relatively low. Conclusion: The proposed MPCC algorithm for the three-level six-phase H-bridge inverters has shown obvious improvement in solving the control problems of multi-vectors and complex redundancy issues.

Evolutionary Gaps Stator Current Control of Multiphase Drives Balancing Harmonic Content

Evolutionary Gaps Stator Current Control of Multiphase Drives Balancing Harmonic Content

A Triangular-Wave Current Control for Parallel-Form Switch-Linear Hybrid Envelope Tracking Power Supply to Achieve High Efficiency

A Triangular-Wave Current Control for Parallel-Form Switch-Linear Hybrid Envelope Tracking Power Supply to Achieve High Efficiency

Discrete-Time Position Sensorless Current Control for Permanent Magnet Synchronous Motors With an Accuracy-Improved Phase-Locked Loop

Discrete-Time Position Sensorless Current Control for Permanent Magnet Synchronous Motors With an Accuracy-Improved Phase-Locked Loop

Sustainable development in Mekong Delta, Vietnam: designing resilient cities based on landscape ecological principles

ABSTRACT Mekong Delta cities are increasingly degrading as a result of urbanization, flood control, and climate change. These cities are increasingly vulnerable to flooding, and current flood control measures are not only inappropriate but also exacerbate the impacts of climate change and urbanization. A flood-resilient city is a solution; however, applying this idea to the actual urban environment through exposure to flood risk is not effective for long-term, sustainable development. This research evaluates landscape structure, changes in land use, and changes in economic, social, and cultural structure, thereby proposing rules for sustainable urban development planning. In addition, this research also suggests a comprehensive functional space plan for Cao Lanh City. This city plays a role as a case study that helps clarify the proposed rules for sustainable urban development planning for Mekong Delta cities in Vietnam.

Tabacco harm reduction: the need for aparadigm shift in German tobacco control policy

The consumption of tobacco continues to be the greatest preventable health risk in Germany. Every year, more than 127,000 people die prematurely as aresult of using tobacco - one in five new cases of cancer is aconsequence of smoking. Germany's current tobacco control policy, consisting of advertising bans, the promotion of smoke-free environments, and an abstinence-only paradigm, are only able to initiate slow change. Other countries have shown how the number of smokers can be reduced and deaths prevented by integrating harm reduction as acomplementary measure and providing amuch more active support for people who want to quit. This article first presents the current situation and current measures in Germany. Then recommendations for changes to the current tobacco control policy in Germany are derived from alook at the United Kingdom, which is considered apioneer throughout Europe with its tobacco control policy, as well as asummary of the current state of research.

The dynamics of hybrid-immune and immunodeficient susceptible individuals and the three stages of COVID-19 vaccination

The World Health Organization has disclosed that the hybrid-immune and immunodeficient individuals are two distinct classes of individuals susceptible to the COVID-19 virus. To model this unique characteristics of two distinct categories of susceptible individuals and the dynamics of the three phases of a vaccination program implemented by the World Health Organization in Malaysia, which have not been accounted for in previous studies, a twelve compartmental SSVEIHQR-D epidemiological model was developed. This model aimed to accurately capture the spread of the COVID-19 virus by fitting real-life data to the model and obtaining updated estimates of the reproduction number. The study also focused on assessing current control measures and exploring strategies to eradicate the virus and mitigate future outbreaks. Mathematical analyses of the model included investigations into stability, equilibrium points, the basic reproduction number R0, optimal control strategies, and sensitivity analyses. Estimation and fitting of the model parameters were conducted using daily situation reports from the Ministry of Health of Malaysia. The obtained value of the basic reproduction number, based on fitted parameter values, indicated stability and reflected the current pandemic situation more realistically. Additionally, the herd immunity threshold was calculated and interpreted in the context of the study findings. Finally, practical insights and recommendations derived from the model’s results were provided to inform government agencies, public health organizations, and intervention bodies, aimed at controlling the spread of the COVID-19 virus.

A dSPACE-based implementation of ANFIS and predictive current control for a single phase boost power factor corrector

This paper presents an innovative control scheme designed to significantly enhance the power factor of AC/DC boost rectifiers by integrating an adaptive neuro-fuzzy inference system (ANFIS) with predictive current control. The innovative control strategy addresses key challenges in power quality and energy efficiency, demonstrating exceptional performance under diverse operating conditions. Through rigorous simulation, the proposed system achieves precise input current shaping, resulting in a remarkably low total harmonic distortion (THD) of 3.5%, which is well below the IEEE-519 standard threshold of 5%. Moreover, the power factor reaches an outstanding 0.990, indicating highly efficient energy utilization and near-unity power factor operation. To validate the theoretical findings, a 500 W laboratory prototype was implemented using the dSPACE ds1104 digital controller. Steady-state analysis reveals sinusoidal input currents with minimal THD and a power factor approaching unity, thereby enhancing grid stability and energy efficiency. Transient response tests further demonstrate the system’s robustness against load and voltage fluctuations, maintaining output voltage stability within an 18 V overshoot and a 20 V undershoot during load changes, and achieving rapid response times as low as 0.2 s. Comparative evaluations against conventional methods underscore the superiority of the proposed control strategy in terms of both performance and implementation simplicity. By harnessing the strengths of ANFIS-based voltage regulation and predictive current control, this scheme offers a robust solution to power quality issues in AC/DC boost rectifiers, promising substantial energy savings and improved grid stability. The results affirm the potential of the proposed system to set new benchmarks in power factor correction technology.

Obscured Contribution of Oxygenated Intermediate-Volatility Organic Compounds to Secondary Organic Aerosol Formation from Gasoline Vehicle Emissions.

Secondary organic aerosol (SOA) formation from gasoline vehicles spanning a wide range of emission types was investigated using an oxidation flow reactor (OFR) by conducting chassis dynamometer tests. Aided by advanced mass spectrometric techniques, SOA precursors, including volatile organic compounds (VOCs) and intermediate/semivolatile organic compounds (I/SVOCs), were comprehensively characterized. The reconstructed SOA produced from the speciated VOCs and I/SVOCs can explain 69% of the SOA measured downstream of an OFR upon 0.5-3 days' OH exposure. While VOCs can only explain 10% of total SOA production, the contribution from I/SVOCs is 59%, with oxygenated I/SVOCs (O-I/SVOCs) taking up 20% of that contribution. O-I/SVOCs (e.g., benzylic or aliphatic aldehydes and ketones), as an obscured source, account for 16% of total nonmethane organic gas (NMOG) emission. More importantly, with the improvement in emission standards, the NMOG is effectively mitigated by 35% from China 4 to China 6, which is predominantly attributed to the decrease of VOCs. Real-time measurements of different NMOG components as well as SOA production further reveal that the current emission control measures, such as advances in engine and three-way catalytic converter (TWC) techniques, are effective in reducing the "light" SOA precursors (i.e., single-ring aromatics) but not for the I/SVOC emissions. Our results also highlight greater effects of O-I/SVOCs to SOA formation than previously observed and the urgent need for further investigation into their origins, i.e., incomplete combustion, lubricating oil, etc., which requires improvements in real-time molecular-level characterization of I/SVOC molecules and in turn will benefit the future design of control measures.

Thrust Ripple Suppression Strategy for Precision Machining Platform by Using Predicted Current Sliding Control

Thrust Ripple Suppression Strategy for Precision Machining Platform by Using Predicted Current Sliding Control

An SMA-based compliant adjustable constant force gripper for micro-assembly

Ensuring precise and consistent force regulation in a confined workspace is critical for high-quality micro-assembly operations. To enhance structural efficiency and reduce system complexity, this study leverages the variable stiffness properties of the shape memory alloy (SMA) and presents a novel compliant adjustable constant force microgripper. In this work, a passive variable stiffness chained pseudo-rigid-body model is established to address the coupling analysis problem arising from the mechanical and SMA’s in-homogeneous phase transformation properties, thereby facilitating the integrated design of the SMA and the mechanism. Exploiting the variable stiffness property of SMA, an improved stiffness-tunable two-beam-binding constant force mechanism is proposed for the gripper jaws, which makes adjustable constant force operation via current control can be achieved straightforwardly. Further, inspired by differential actuation mode, a compact SMA-based actuator comprising two parallel guide mechanisms and SMA drivers is developed to meet the requirement for the large working stroke of the gripper. Numerical simulations and experimental studies validate the design model’s efficiency and the proposed structures’ capabilities, and also prove the gripper’s constant operation force value can be regulated in the range of 0.152 to 0.381 N. With dimensions of 35×56.5×7 mm3 and a maximum stroke of 2.077mm, the gripper demonstrates fine compactness and potential for continuous, cross-scale micro-assembly.

A new topology of non-isolated AC-DC quadratic boost converter with enhanced power traits

A novel AC-DC quadratic boost converter (QBC) topology is presented in this paper which can provide higher power factor (PF), lower total harmonic distortion (THD) and higher voltage when compared to a conventional AC-DC boost convertero This is achieved by using additional switched capacitor and switched inductor in the power processing stage. The presented converter is analyzed theoretically, and a voltage gain equation is derived. A simulation model is created to evaluate the converter performance under various duty cycles, switching frequency, and changing output load. The input PF, THD, and voltage gain of the simulated model were compared with conventional converter to determine the validity of the suggested converter circuit. The results show that the efficiency, PF, THD and voltage gain value reaches approximately 97.9%, 0.98, 16.14, and 2.83 respectively at a duty cycle of 50% with fixed output load of 100 Ω. A dual loop voltage and current controller is also arrayed with the proposed circuit which allows further enhancement in PF (0.997) and THD (7.45%). This converter can be a suitable option for systems where isolation is not necessary but high PF, high voltage gain and low THD are required.

Current Loop Control of Jet Fan Motors in Thu Thiem Tunnel by the Exact Linearization Method

Current Loop Control of Jet Fan Motors in Thu Thiem Tunnel by the Exact Linearization Method

Data-Driven Distributed H ∞ Current Sharing Consensus Optimal Control of DC Microgrids via Reinforcement Learning

Data-Driven Distributed <i>H</i> _∞ Current Sharing Consensus Optimal Control of DC Microgrids via Reinforcement Learning

Current Balancing Control Method With Reduced Number of Current Sensors for Interleaved LLC Converters

Current Balancing Control Method With Reduced Number of Current Sensors for Interleaved LLC Converters

Advanced Optimal Tracking Control With Stability Guarantee via Novel Value Learning Formulation.

In this article, to solve the optimal tracking control problem (OTCP) for discrete-time (DT) nonlinear systems, general value iteration (GVI) scheme and online value iteration (VI) algorithms with novel value function are discussed. First, the disadvantage of the traditional value function for the OTCP is presented and the novel value function is introduced. Second, we analyze the monotonicity and convergence of GVI and establish the admissibility condition of GVI to evaluate the admissibility of the current iterative control. Note that a novel approach is introduced to analyze the admissibility. Third, based on the attraction domain, improved control policies with online VI can be obtained by judging the location of the current tracking error and reference point. Finally, the stability of the online VI-based control system is guaranteed. Besides, we provide two simulation examples to show the performance of the proposed methods.

Current Interharmonic Prediction Control Based on MPC and Lyapunov for Grid-Connected PV System

Current Interharmonic Prediction Control Based on MPC and Lyapunov for Grid-Connected PV System