Flux Control Research Articles

Design and improvement of torque characteristics of half‐wave rectified variable field flux motor with axial gap structure

AbstractThe axial gap structure of a half‐wave rectified variable field flux motor (AG‐HVFM) has been proposed, which has a double stator structure and field winding short‐circuited by a diode. Although the AG‐HVFM can achieve a high‐efficiency drive in wide speed and torque range via variable field flux control, its structure deteriorates the average torque and torque ripple. In this paper, we sequentially design the core shape, aspect ratio, and current control method for an AG‐HVFM to improve its torque characteristics.

Speed regulation of PMSM drive in electric vehicle applications with sliding mode controller based on harris Hawks optimization

This paper focuses on the speed regulation of permanent magnet synchronous motors (PMSM) in electric vehicle application using sliding mode control (SMC). Harris hawks optimizations (HHO) based sliding mode controller is adopted to increase the dynamic response of the PMSM motor, thereby enhancing vehicle performance. For the independent control of torque and flux, field oriented-control (FOC) is used to drive the PMSM. In this work, the speed reference provided for the controller is based on an electric car driving cycle that replicates real-world driving conditions. The optimal selection of sliding mode controller parameter enhances the dynamic characteristics of the speed regulation in electric vehicles, which is validated using the hardware in the loop (HIL-402) device. The HHO based sliding mode controller has superior performance in terms of robustness against load disturbances, fast convergence, and tracking accuracy.

Long-chain fatty acids mediate hepatic metabolic flux in preruminating dairy calves fed flaxseed oil, high oleic soybean oil, or milk fat

Nutrition and physiological state affect hepatic metabolism. Our objective was to determine if feeding flaxseed oil (∼50% C18:3n-3 cis), high oleic soybean oil (∼70% C18:1 cis-9), or milk fat (∼50% C16:0) alters hepatic expression of PC, PCK1, and PCK2 and the flow of carbons from propionate and pyruvate into the TCA cycle in preruminating calves. Male Holstein calves (n = 40) were assigned to a diet of skim milk with either: 3% milk fat (MF; n = 8), 3% flaxseed oil (Flax; n = 8), 3% high oleic soybean oil (HOSO; n = 8), 1.5% MF + 1.5% high oleic soybean oil (MF-HOSO; n = 8), or 1.5% MF + 1.5% flaxseed oil (MF-Flax; n = 8) from d 14 to d 21 postnatal. At d 21 postnatal, a liver biopsy was taken for gene expression and metabolic flux analysis. Liver explants were incubated in [U-13C] propionate and [U-13C] pyruvate to trace carbon flux through TCA cycle intermediates or with [U-14C] lactate, [1-14C] palmitic acid, or [2-14C] propionate to quantify substrate oxidation to CO2 and acid soluble products. Compared with other treatments, plasma C18:3n-3 cis was 10 times higher and C18:1 cis-9 was 3 times lower in both flax (Flax and MF-Flax) treatments. PC, PCK1, and PCK2 expression and flux of [U-13C] pyruvate as well as [U-13C] propionate were not different between treatments. PC expression was negatively correlated with the enrichment of citrate M+5 and malate M+3, and PCK2 was negatively correlated with citrate M+5, suggesting that when expression of these enzymes is increased, carbon from pyruvate enters the TCA cycle via PC mediated carboxylation, and then OAA is converted to phosphoenolpyruvate via PCK2. Acid soluble product formation and PC expression were reduced in HOSO (MF-HOSO and HOSO) treatments compared with flax (MF-Flax and Flax), indicating that fatty acids regulate PC expression and carbon flux, but that fatty acid flux control points are not connected to PC, PCK1, or PCK2. In conclusion, fatty acids regulate hepatic expression of PC, PCK1, and PCK2, and carbon flux, but the point of control is distinct.

Model-free predictive flux vector control for N ∗ 3-Phase PMSM drives considering parameters mismatch

This paper develops a novel model free-predictive flux vector control method (MF-PFVC) for high-performance stator flux and torque monitoring of the multi-module three-phase PMSM (N ∗ 3-Phase PMSM) drive with parameters mismatch. The proposed MF-PFVC method is based on a convenient combination of direct predictive torque control (PTC) and model free predictive control techniques. First, the voltage source inverter (VSI) vector control of N ∗ 3-Phase PMSM is determined by the three-segment stator windings structure. Then, the parameter mismatch sensitivity of the N ∗ 3-Phase PMSM drive system is analyzed based on the conventional PTC. Furthermore, a novel MF-PFVC method with multivariable unknown disturbance integral terminal sliding mode observer (SMO) is proposed for N ∗ 3-Phase PMSM drive, which can effectively enhance robustness against the parameters mismatch. Finally, compared with the conventional PTC, the simulation and experimental results of MF-PFVC method illustrated improved stator flux control performance concerning lower stator flux ripple as well as reduced torque ripple while it can eliminate the influence of parameter mismatch.

OptoLacI: optogenetically engineered lactose operon repressor LacI responsive to light instead of IPTG.

Optogenetics' advancement has made light induction attractive for controlling biological processes due to its advantages of fine-tunability, reversibility, and low toxicity. The lactose operon induction system, commonly used in Escherichia coli, relies on the binding of lactose or isopropyl β-d-1-thiogalactopyranoside (IPTG) to the lactose repressor protein LacI, playing a pivotal role in controlling the lactose operon. Here, we harnessed the light-responsive light-oxygen-voltage 2 (LOV2) domain from Avena sativa phototropin 1 as a tool for light control and engineered LacI into two light-responsive variants, OptoLacIL and OptoLacID. These variants exhibit direct responsiveness to light and darkness, respectively, eliminating the need for IPTG. Building upon OptoLacI, we constructed two light-controlled E.coli gene expression systems, OptoE.coliLight system and OptoE.coliDark system. These systems enable bifunctional gene expression regulation in E.coli through light manipulation and show superior controllability compared to IPTG-induced systems. We applied the OptoE.coliDark system to protein production and metabolic flux control. Protein production levels are comparable to those induced by IPTG. Notably, the titers of dark-induced production of 1,3-propanediol (1,3-PDO) and ergothioneine exceeded 110% and 60% of those induced by IPTG, respectively. The development of OptoLacI will contribute to the advancement of the field of optogenetic protein engineering, holding substantial potential applications across various fields.

Revealing the role of interlayer spacing in radioactive-ion sieving of functionalized graphene membranes

Functionalization of graphene enables precise control over interlayer spacing during film formation, thereby enhancing the separation efficiency of radioactive ions in graphene membranes. However, the systematic impact of interlayer spacing of graphene membranes on radioactive-ion separation remains unexplored. This study aims to elucidate how interlayer spacing in functionalized graphene membranes affects the separation of radioactive ions. Utilizing polyamidoxime (PAO) to modify graphene oxide, we controlled the interlayer spacing of graphene membranes. Experimental results indicate that tuning interlayer spacing enables control of the permeation flux of radioactive ions (UO22+ 1.01 × 10−5–8.32 × 10−5 mol/m2·h, and K+ remains stable at 3.60 × 10−4 mol/m2·h), and the K+/UO22+ separation factors up to 36.2 at an interlayer spacing of 8.8 Å. Using density functional theory and molecular dynamics simulations, we discovered that the effective separation is mainly determined via interlayer spacing and the quantity of introduced functional groups, explaining the anomalous high permeation flux of target ions at low interlayer spacing (4.3 Å). This study deepens our comprehension of interlayer spacing within nanoconfined spaces for ion separation and recovery via graphene membranes, offering valuable insights for the design and synthesis of high-performance nanomembrane materials.

A Novel Three-Vector-Based Model Predictive Flux Control With Low Computation Complexity for SPMSM

A Novel Three-Vector-Based Model Predictive Flux Control With Low Computation Complexity for SPMSM

Speed control for traction motor of urban electrified train in field weakening region based on backstepping method

Tractor motors always operate in the speed region higher than rated speed, but is limited to the module of the stator current, stator voltage vectors. Additionally, mathematical model of traction motor has shown nonlinearity through the product of the state variables 𝑖𝑠𝑑, 𝑖𝑠𝑞 with the input variable 𝜔𝑠:𝜔𝑠𝑖𝑠𝑞, 𝜔𝑠𝑖𝑠𝑑. Therefore, this paper focuses on the study of speed control of traction motors in weakening field region while optimizing torque control, and choosing the backstepping method in designing speed–flux controller in order to solve the nonlinear structure. The simulation results of the responses: speed, torque, power, and flux performed on MATLAB/Simulink software with parameters collected from metro Nhon-Hanoi Station, Vietnam have proven the correctness in theoretical research.

A Wide-Speed Range Three-Vector-Based Model Predictive Flux Control With Improved Predictive Model for PMSM Drives

A Wide-Speed Range Three-Vector-Based Model Predictive Flux Control With Improved Predictive Model for PMSM Drives

Accurate Modeling and Optimal Rotor Flux Control of a Bearingless Induction Motor With the Specific Pole

Accurate Modeling and Optimal Rotor Flux Control of a Bearingless Induction Motor With the Specific Pole

Resveratrol Inhibits VDAC1-Mediated Mitochondrial Dysfunction to Mitigate Pathological Progression in Parkinson's Disease Model.

An increase in α-synuclein (α-syn) levels and mutations in proteins associated with mitochondria contribute to the development of familial Parkinson's disease (PD); however, the involvement of α-syn and mitochondria in idiopathic PD remains incompletely understood. The voltage-dependent anion channel I (VDAC1) protein, which serves as a crucial regulator of mitochondrial function and a gatekeeper, plays a pivotal role in governing cellular destiny through the control of ion and respiratory metabolite flux. The ability of resveratrol (RES), which is a potent phytoalexin with antioxidant and anti-inflammatory properties, to regulate VDAC1 in PD is unknown. The objective of this study was to evaluate the role of VDAC1 in the pathological process of PD and to explore the mechanism by which resveratrol protects dopaminergic neurons by regulating VDAC1 to maintain the mitochondrial permeability transition pore (mPTP) and calcium ion balance. The effects of RES on the motor and cognitive abilities of A53T mice were evaluated by using small animal behavioral tests. Various techniques, including immunofluorescence staining, transmission electron microscopy, enzyme-linked immunoadsorption, quantitative polymerase chain reaction (PCR), and Western blotting, among others, were employed to assess the therapeutic impact of RES on neuropathy associated with PD and its potential in regulating mitochondrial VDAC1. The findings showed that RES significantly improved motor and cognitive dysfunction and restored mitochondrial function, thus reducing oxidative stress levels in A53T mice. A significant positive correlation was observed between the protein expression level of VDAC1 and mitochondrial α-syn expression, as well as disease progression, whereas no such correlation was found in VDAC2 and VDAC3. Administration of RES resulted in a significant decrease in the protein expression of VDAC1 and in the protein expression of α-syn both in vivo and in vitro. In addition, we found that RES prevents excessive opening of the mPTP in dopaminergic neurons. This may prevent the abnormal aggregation of α-syn in mitochondria and the release of mitochondrial apoptosis signals. Furthermore, the activation of VDAC1 reversed the resveratrol-induced decrease in the accumulation of α-syn in the mitochondria. These findings highlight the potential of VDAC1 as a therapeutic target for PD and identify the mechanism by which resveratrol alleviates PD-related pathology by modulating mitochondrial VDAC1.

Real-time and hardware in the loop validation of electric vehicle performance: Robust nonlinear predictive speed and currents control based on space vector modulation for PMSM

The transport industry's environmental impact has prompted various stakeholders to focus more on electric vehicles as a potential solution. Extensive research on electric vehicle motor control reveals their complexity, highlighting the crucial role of the traction motor control mechanism being one of their essential subsystems. This study presents a novel approach to control the drive system of an electric vehicle's permanent magnet synchronous motor, using a robust non-linear model predictive control in a cascaded structure combined with a space vector modulation technique. The formulation of the robust non-linear model predictive control law involves optimizing a new cost function with the inclusion of an integral action in the controller to ensure zero steady-state error. An important aspect of this control approach is its ability to enhance robustness without needing information about external perturbations and parameter uncertainties. Moreover, the space vector modulation technique is designed to address the issue of current harmonic distortion by carefully selecting appropriate switching vectors. The appropriate selection for space voltage vectors for every sampling period maintains a consistent switching frequency. As a result, the SVM can enhance torque-rippled regulation and accomplish effective flux and torque control. The performance of the proposed control system is evaluated through a series of numerical simulations using MATLAB/Simulink. The simulation results are analyzed and compared to assess the effectiveness of the proposed control system in terms of tracking accuracy, disturbance rejection, robustness against parameter uncertainties, reduction of torque, and current ripples. To further validate the numerical simulation results, a hardware-in-the-loop (HIL) setup is established using the OPAL-RT platform. Furthermore, experimental validation on a PMSM utilizing the dSPACE DS1202 board is carried out, demonstrating the efficacy of the proposed control system. These findings validate the suggested control technique's robustness and efficiency.

Comparative study between sliding mode and DTC of doubly fed induction machine

Although the great advance in term of AC machine construction, control strategies are also necessary to be developed and improved continuously satisfying output torque/power. Hence the Doubly fed induction motor (DFIM)is widely used in industry, since it can operates in wide range of speed variation around the synchronous speed and the control of flux and torque is independent. In this paper, control of doubly fed induction motor (DFIM) has been investigated, which two control strategies have been studied and compared: the first strategy uses a sliding mode control (SMC); the second employs Direct Torque Control (DTC). Modeling of DFIM and details of both control strategies have been presented. the mathematical description of different basic dynamic models of the DFIM have been carried out The performances in terms of torque tracking, accuracy and robustness of both control techniques under normal and various speed and load conditions have been demonstrated and compared.

High-Efficient Direct Power Control Scheme Using Predictive Virtual Flux for Three-Phase Active Rectifiers

In recent years, the pulse-width-modulation (PWM) converter has been found to have extensive applications in renewable energy, industrial fields, and others. The high efficiency requirement is crucial to operating a PWM rectifier in various applications, in addition to the fundamental control objectives of sinusoidal grid currents and the correct DC bus voltage. Additionally, in practical application, another issue arises when the grid voltage frequently experiences distortion, leading to a distorted grid current and a significant rise in total harmonic distortion (THD). To resolve these problems, a model predictive virtual flux-based direct power control (MPVFDPC) with improved power loss performance is proposed based on an integrated switching state predetermination strategy. The proposed MPVFDPC for PWM rectifier inherits the merits of both virtual flux control and direct power control, which have fast dynamic performance and the grid current THD is considerably decreased under distorted grid voltage states. The proposed technique aims to minimize switching loss under ideal and distorted grid voltage states by exploiting the discontinuous modulation concept by using a switching state predetermination strategy. The MPVFDPC with switching state predetermination strategy is proven by employing it in experiments as well as simulations in comparison with previous models: predictive direct power control (Conv. MPDPC) and conventional MPVFDPC (Conv. MPVFDPC). The acquired waveforms and quantitative data are employed to prove the effectiveness of the developed algorithm.

Robust fuzzy – backstepping mode control of an induction motor

This paper presents a novel control for induction motors using backstepping control and fuzzy logic. The Backstepping control is suggested as a substitute for the conventional PI controller to attain high-performance motion control systems for the speed, flux, and current control loops. Stability analysis, based on Lyapunov theory, is also conducted to guarantee the convergence of the speed tracking error from all possible initial conditions. The speed regulator was changed to a fuzzy logic regulator. The simulation results confirm that the proposed hybrid control fuzzy-backstepping scheme offers improved performance in terms of trajectory tracking ability and robustness against variation when subjected to time-varying reference input.

Concentration Recognition-Based Auto-Dynamic Regulation System (CRUISE) Enabling Efficient Production of Higher Alcohols.

Microbial factories lacking the ability of dynamically regulating the pathway enzymes overexpression, according to in situ metabolite concentrations, are suboptimal, especially when the metabolic intermediates are competed by growth and chemical production. The production of higher alcohols (HAs), which hijacks the amino acids (AAs) from protein biosynthesis, minimizes the intracellular concentration of AAs and thus inhibits the host growth. To balance the resource allocation and maintain stable AA flux, this work utilizes AA-responsive transcriptional attenuator ivbL and HA-responsive transcriptional activator BmoR to establish a concentration recognition-based auto-dynamic regulation system (CRUISE). This system ultimately maintains the intracellular homeostasisof AA and maximizes the production of HA. It is demonstrated that ivbL-driven enzymes overexpression can dynamically regulate the AA-to-HA conversion while BmoR-driven enzymes overexpression can accelerate the AA biosynthesis during the HA production in a feedback activation mode. The AA flux in biosynthesis and conversion pathways is balanced via the intracellular AA concentration, which is vice versa stabilized by the competition between AA biosynthesis and conversion. The CRUISE, further aided by scaffold-based self-assembly, enables 40.4gL-1 of isobutanol production in a bioreactor. Taken together, CRUISE realizes robust HA production and sheds new light on the dynamic flux control during the process of chemical production.

Deoxyxylulose 5-Phosphate Synthase Does Not Play a Major Role in Regulating the Methylerythritol 4-Phosphate Pathway in Poplar.

The plastidic 2-C-methylerythritol 4-phosphate (MEP) pathway supplies the precursors of a large variety of essential plant isoprenoids, but its regulation is still not well understood. Using metabolic control analysis (MCA), we examined the first enzyme of this pathway, 1-deoxyxylulose 5-phosphate synthase (DXS), in multiple grey poplar (Populus × canescens) lines modified in their DXS activity. Single leaves were dynamically labeled with 13CO2 in an illuminated, climate-controlled gas exchange cuvette coupled to a proton transfer reaction mass spectrometer, and the carbon flux through the MEP pathway was calculated. Carbon was rapidly assimilated into MEP pathway intermediates and labeled both the isoprene released and the IDP+DMADP pool by up to 90%. DXS activity was increased by 25% in lines overexpressing the DXS gene and reduced by 50% in RNA interference lines, while the carbon flux in the MEP pathway was 25-35% greater in overexpressing lines and unchanged in RNA interference lines. Isoprene emission was also not altered in these different genetic backgrounds. By correlating absolute flux to DXS activity under different conditions of light and temperature, the flux control coefficient was found to be low. Among isoprenoid end products, isoprene itself was unchanged in DXS transgenic lines, but the levels of the chlorophylls and most carotenoids measured were 20-30% less in RNA interference lines than in overexpression lines. Our data thus demonstrate that DXS in the isoprene-emitting grey poplar plays only a minor part in controlling flux through the MEP pathway.

Torque and flux control of induction motors fed by synchronized and symmetrical voltage pulses

SummaryThe low switching frequency in high‐power motor drives is mandatory for reducing thermal stress on power devices but often results in significant current harmonics. Synchronized space vector modulation (SynSVM), a widely used low‐carrier‐ratio PWM strategy, offers a simple implementation and reduced harmonics. However, implementing SynSVM in traditional AC motor current regulation poses challenges due to fixed voltage samples. To address this, a high‐performance control scheme based on SynSVM is proposed in this manuscript. It ensures the stator flux vector follows a predefined trajectory by integrating voltage pulses from the original SynSVM. The basic voltage vector switching is facilitated through high‐frequency monitoring and compensation of torque and flux errors, resulting in a fast torque response. Furthermore, synchronized and symmetrical voltage pulses, inherent in the original SynSVM, are equivalently generated, to effectively mitigate current harmonics. This proposed method liberates designers from the complexities of current regulation based on SynSVM. Both simulations and experiments validate the efficacy of the proposed method.

Real-time control of NBI fast ions, current-drive and heating properties

Conventionally, neutral beam injection (NBI) in tokamaks is controlled via engineering parameters such as injection voltage and power. Recently, the high-fidelity real-time NBI code RABBIT has been coupled to the discharge control system of ASDEX Upgrade. It allows to calculate the NBI fast-ion distribution and hence the properties of NBI in real-time, making it possible to control them directly. We successfully demonstrate control of driven current, ion heating and stored fast-ion energy by modifying the injected beam power. A combined ECRH and NBI controller is also successfully tested, which is able to adjust the heating mix between ECRH and NBI to match a certain desired ion heating fraction at given total power. Further experiments have been carried out towards control of the ion heat flux (i.e. ion heating plus collisional heat transfer between ions and electrons). They show good initial success, but also leave room for future improvements as the controller runs into instabilities at too high requests.

Albumin is an important factor in the control of serum free fatty acid flux in both male and female mice.

Albumin knockout (Alb-/-) mice exhibit a low plasma free fatty acid (FFA) concentration, but it was not known if the suppressed concentration reflects a lower rate of appearance (Ra) of FFA in the circulation (i.e., lower FFA flux) or if the absence of albumin alters the relationship between FFA flux and concentration. For understanding the role of albumin in FFA transport through the bloodstream, it is not sufficient to rely on FFA concentration data alone. Therefore, we developed a method to study FFA kinetics in Alb-/- mice. Using an albumin-free formulation of [U-13C]palmitate tracer, serum FFA kinetics were tested in Alb-/- and wild-type (WT) mice. Results indicate that the flux of FFA in serum of Alb-/- mice was significantly lower than in WT mice (P < 0.05), while albumin deficiency did not alter the relationship between FFA flux and concentration. Next, to test if suppressed lipolysis might have also been involved in the suppressed FFA kinetics, gene expression of a lipolytic enzyme (adipose triglyceride lipase, Atgl) and a marker of lipolysis (phosphorylation of hormone-sensitive lipase, p-HSL) were measured in adipose tissue. In contrast to the low FFA flux in Alb-/-, both Atgl gene expression and p-HSL protein were significantly higher in adipose tissue of Alb-/- than in WT mice (P < 0.05). Thus, the low FFA flux in Alb-/- appeared to be driven by the absence of albumin's FFA binding functions rather than through regulation of lipolysis, indicating that albumin is an important factor in determining the flux of FFA in circulation.NEW & NOTEWORTHY To improve understanding of the albumin protein's function in vivo, we tested plasma free fatty acid kinetics in albumin knockout mice compared with wild-type mice. Using a new tracer formulation strategy, it was discovered that the appearance rate of free fatty acids in serum is lower in albumin knockout mice than in wild-type mice. The results indicate that albumin is a major controller of free fatty acid kinetics.