Linear Regulator Research Articles

Analysis and Simulation of Overmodulation Modes of a Three-Inverter Block of the Photovoltaic Installation

The purpose of this work is to modernize the control scheme of a transformer-based photovoltaic system with three inverters controlled by the modified algorithms of synchronous spacevector PWM in order to ensure linear regulation of the system in the overmodulation zone of the inverter block in the process of forming a symmetrical and synchronized (with the operating frequency of the system) voltage on the inverter-side windings of a power transformer. This goal is achieved by the fact that the process of two-stage control of the system in the zone of overmodulation of inverters is carried out on the basis of synchronized phase shifts between the control signals of inverters (a constant phase shift, as well as an additional adjustable phase shift between the inverter signals as a function of the duration of clock subintervals), with an appropriate modification of the algorithms of synchronous PWM of inverters due to the inclusion of two specialized correction factors in the basic functional dependencies. The most significant results of the work include the fact that in a system with a modified control scheme and modulation of the inverter block in the overmodulation zone, the resulting voltage on the inverter-side windings of the power transformer is characterized by quarterwave symmetry, and its spectrum contains no even-order harmonics, as well as subharmonics, including regimes of fluctuations in the operating frequency of the system connected to a three-phase network, thereby helping to reduce losses in the transformer windings and improve the efficiency of photovoltaic systems.

Design and simulation of low dropout voltage regulator using 180nm technology

Low Dropout (LDO) Voltage Regulators are the linear regulators which drives upon a very small differential voltage. The main components of the Low dropout voltage regulators are Error amplifier, Pass device, voltage reference source and Voltage divider network. The low dropout voltage regulator uses a variable input to give a steady, constantly controlled, low-noise DC output voltage. This is a linear voltage regulator that includes a small voltage drop among the input as well as the output that works even when the output voltage is extremely close to the input voltage. The Error amplifier circuit which is one of the components in Low dropout voltage regulator is designed in the standard 180nm CMOS technology, with supply voltage of 1.6V, the gain of the error amplifier is 74db, Band-gap reference circuit is implemented to produce stable reference voltage which is independent of temperature variations. The bandgap reference voltage circuit gives the output voltage of 1.2V. The low dropout voltage regulator produces constant output voltage of 1.8V for the input voltage range 2.1V to 3.5V and it provides constant output voltage for load variations.

Employing simplified resistance–inductance–capacitance equivalent circuits to analyze and confirm a gallium nitride‐based current linear regulator for laser diode controls

Employing simplified resistance–inductance–capacitance equivalent circuits to analyze and confirm a gallium nitride‐based current linear regulator for laser diode controls

ALDO2, a multi-function rad-hard linear regulator for SiPM-based HEP detectors

ALDO2 is a multi-function, adjustable, low dropout linear regulator designed in onsemi I3T80 0.35μm HV CMOS technology for use in HEP detectors that adopt silicon photomultipliers (SiPMs). The chip features four independent regulators, two low voltage channels (max 3.3 V) used to filter and stabilize the power supply of front-end chips, and two HV channels (max 70 V), specifically designed to provide the bias voltage to arrays of SiPMs. Each regulator can be independently shut down and is protected for over-current and over-temperature. The HV regulators also implement a circuit to monitor the bias current of the SiPM arrays, allowing to perform I–V curves and thus to fine-tune the working point of the SiPM arrays during the detector lifetime. The chip adopts radiation hardening techniques and has been fully qualified up to a TID of 20 Mrad, a 1-MeV-equivalent neutron fluence of 1015 cm−2, and with heavy ions up to 40 MeV cm2 mg−1 LET and 1010 cm−2 cumulative fluence. The chip will be installed in two CMS detectors in the HL-LHC phase, the Barrel Timing Detector (BTL) and the High Granularity Calorimeter (HGCAL).

Graphene-Based Soft Actuator with Dynamic Spectrum Modulation for a Smart Thermal Surface

Two-dimensional structures enable ion activation and actuation. These structures also enable ions to intercalate, shifting the energy level and altering the optical absorption. In this study, a dual-function, graphene-based smart surface with actuation and spectrum regulation was developed. This surface was composed of a graphene working electrode, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide electrolyte, and a Au counter electrode. The smart surface could vary its thickness by 17.4% and regulate multiple wavelengths, including ultraviolet, visible, near-, and mid-infrared. Within a 2.2–3.3 V electric field, linear emissivity regulation was established, and the highest emissivity modulation depth approached 0.41. By investigating electromechanical, electrochemical, in situ structural, and electrical features, three stages of ion movement under electrical voltage, including dispersion, intercalation into graphene layers, and double layer capacitance, were observed. The ion intercalation process was associated with Fermi level shifting and dynamic spectrum turning of graphene, whereas the production of double layer capacitance was associated with the maximum modulation depth. Such soft actuators with dynamic spectrum tunability may render smart thermal surfaces feasible for other application scenarios, for example, thermal camouflage robotics, optical communication, and radiative cooling.

Hydrolysates of whole forage-fish and Pacific krill are useful to reduce fish meal in practical diets for largemouth bass (Micropterus salmoides), and dietary fish hydrolysate suppresses expressions of intestinal oligopeptide transporter and taurine transporter genes

Somatic and expressional effects of replacing dietary fishmeal (FM) with a 1:1:2 combination of soy protein concentrate, corn gluten meal, and hydrolysate of forage-fish (HWF) or Pacific krill (HPK) were investigated in juvenile largemouth bass for 66 days. The control diet (FMC) contained 320 g kg−1of FM. Six extruded diets were produced with 3 rates of replacement at 25 %, 50 % and 75 % protein for each of the two hydrolysate combinations. Feed intake (FI) and weight gain (WGR) did not differ between fish fed HWF diets and FMC. Fish fed HPK50 and HPK75 had lower FI and WGR. FI linearly decreased with increasing HPK, while feed conversion ratio (FCR) increased. No significance was found in the FCR among groups fed FMC, HWF25, HWF50, and HPK25, whereas HWF75, HPK50, and HPK75 groups had significantly higher FCR. The apparent digestibility (AD) of crude protein (CP) increased with increasing HWF while HPK didn’t cause significant change. AD of lipid and energy were not affected by diet, and AD of most amino acids increased proportionally with HWF. No proximate composition or retention of crude or digestible protein or energy other than whole-body ash revealed HWF-related differences. Whole-body CP, lipid, ash contents and CP retentions showed significant dose response in HPK fed fish. The condition factor decreased linearly with increasing HPK. Fish fed HPK50 diet upregulated peptide transporter 1 (pept1) expression in the foregut. Expressions of both taurine transporter (taut) and pept1 were upregulated by increasing replacement from 0 % to 25 % HWF. Further increase in HWF replacement caused linear down regulation in expression of both transporters. In conclusion, HWF and HPK facilitated reduced use of fishmeal in practical diet for largemouth bass. Expressions of pept1 and taut were dose-dependent in fish fed HWF. HPK just caused single diet upregulation.

Performance analysis of impulsive station-keeping strategies for cis-lunar orbits with the ephemeris model

Future long-term lunar missions, such as cis-lunar space stations and communication/navigation constellations, have been proposed by different space agencies. For such long-term missions, reliable station-keeping strategies are of great importance to counteract unfavourable effects of perturbations, navigation errors, etc. In this study, representative cis-lunar orbits with favourable characteristics, including near rectilinear halo orbits (NRHOs), distant retrograde orbits (DROs), and halo orbits, are considered as nominal orbits of long-term lunar missions for station-keeping analysis. Both the target point method and the discrete linear quadrant regulator (DLQR) control are applied to these nominal orbits in the ephemeris model. Under some practical constraints caused by the navigation and orbital control systems, Monte-Carlo simulations are carried out to evaluate performances of the station-keeping strategies. Then, effects of solar radiation pressure (SRP) and nonspherical lunar gravity on the station-keeping performances are demonstrated by Monte-Carlo simulations with low-fidelity nominal orbits constructed in ephemeris models without SRP or nonspherical lunar gravity. Finally, comparisons between different impulse intervals are made to find the balance between the station-keeping cost and position deviation. It is found that the stability index of the nominal orbit has no direct effect on the station-keeping cost, but plays an important role in the selection of the impulse interval. The DROs and NRHOs allow a much longer impulse interval than the unstable halo orbits. The results can provide useful references for selections of the nominal orbit and station-keeping strategy in future long-term lunar missions.

Current Context and Research Trends in Linear DC–DC Converters

With the introduction of switch-mode power supplies (SMPS) in the mid-1970s, the efficiency of DC–DC conversion rose from 60 to 80% and SMPS became a popular power supply solution. However, linear regulators have not become obsolete. The modern power management system in portable devices supports a complex mix of DC–DC converters, combining switch-mode power supplies (SMPS), switched capacitor converters (SCCs), and linear regulators in the form of low-dropout regulators (LDOs). LDOs are used to supply low-voltage DC power rails with very low noise and high current slew rate capability, which are usually fed by the output rail of SMPS. This paper provides a comprehensive review of the evolution of the application scope of linear-type DC–DC converters in the power supply context and the present research trends. First, we review the context of linear DC–DC converters in detail, particularly in portable device power supplies. Then, the details of LDO regulators and their recent industry development and research trends are discussed. Then, the discussion focuses on supercapacitor-assisted low-dropout (SCALDO) regulator design and its scope in the portable device power management together with SCALDO-based dual output and reduced switch designs, and finally, the conclusions follow.

Inductor Saturation Compensation in Three-Phase Three-Wire Voltage-Source Converters Via Inverse System Dynamics

In three-phase three-wire (3P3W) voltage-source converter (VSC) systems, utilization of filter inductors with deep saturation characteristics is often advantageous due to the improved size, cost, and efficiency. However, with the use of conventional synchronous frame current control methods, the inductor saturation results in significant dynamic performance loss and poor steady-state current waveform quality. This article proposes an inverse dynamic model-based compensation (IDMBC) method to overcome these performance issues. For this purpose, two-phase exact modeling of the 3P3W VSC control system is obtained. Based on the modeling, the inverse system dynamic model of the nonlinear system is obtained and employed such that the nonlinear plant is converted to a virtual linear inductor system for linear current regulators to perform satisfactorily. Further, to control phase currents in the synchronous frame, a two-phase coordinate transformation is proposed. The IDMBC method is tested via dynamic command response and waveform quality simulations and experiments that employ saturable inductors reaching down from full inductance at zero current to 1/9th inductance at full current. The results obtained demonstrate the suitability of the method for 3P3W VSCs employing saturable inductors.

Study of the Angular Positioning of a Rotating Object Based on Some Computational Intelligence Methods

The paper presents the result of a study that can be included in the broader field of research aimed at increasing the performance of automatic motion control systems. The main contribution of the article is the comparative study of three control methods from the domain of computational intelligence—state feedback fuzzy control, neural predictive control, and neural model reference control—and three linear control methods—error feedback control, digital control, and state feedback control, in the case of positioning a rotating object around a central axis. The developed control structures were modeled and simulated using MATLAB/Simulink. The paper presents the chosen control structures; how to dimension them; the parameters of the linear, fuzzy, and neural regulators; the training parameters of the neural networks; and the characteristics of the variables of the control systems in the transient regime and the steady-state regime. Transient characteristics obtained for the six control structures are compared from the point of view of their control efficiency criteria. The differences in performance criteria between the control methods studied are small. All these studied methods make the regulated system to be carried on various state trajectories, short response times are obtained with aperiodic and asymptotic behavior, and the differences between the values of the efficiency indicators are small.

Optimized Power Supply Rejection Ratio Modeling Technique for Simulation of Automotive Low-Dropout Linear Voltage Regulators

In the automotive domain, the vast majority of testing is performed through simulations, which can validate a system design before the actual implementation and can emphasize eventual faults in the design process. Hence, the simulation is of utmost importance. Behavioral models are necessary for the creation of each electronic device desired in the system, and some of the components have very complex behavior: low-dropout linear voltage regulators (LDOs), gate drivers, and switching regulators. In the automotive industry, LDOs are essential components because they power all the other subsystems and very accurate behavior is needed to make sure that the system behaves as in reality. LDO models are already commercially available and most of their intrinsic characteristics are modeled (dropout voltage, line regulation, load regulation, etc.). However, one characteristic that is extremely useful, yet the hardest to model, is the power supply rejection ratio (PSRR). This paper proposes a new PSRR modeling technique for automotive low-dropout voltage regulators. The new PSRR characteristic was modeled for an automotive LDO product in a Texas Instruments portfolio, which has a commercially available model, and was simulated using the PSpice Allegro simulator and the OrCAD Capture CIS environment.

The radiation tolerance of a low voltage LDO developed for the CMS HGCAL on-detector electronics system

The CMS detector will undergo the replacement of its current endcap calorimeter by a new high granularity calorimeter (HGCAL). The new HGCAL will need to withstand much higher radiation levels than the present endcaps. This poses tight requirements on the front-end electronics, including the powering chain. As part of this chain, a low-dropout linear regulator (LDO) has been designed and prototyped for post-regulation for HGCAL, providing extremely low noise and stable power to the analog front-end. We present results from tests of the LDO, including from a detailed irradiation campaign.

DESIGN AND SIMULATION OF BUILDING BLOCKS OF A LOW-DROPOUT VOLTAGE REGULATOR

Low dropout regulators (LDOs) are a simple and inexpensive way to regulate an output voltage that is powered from a higher voltage input [1]. An LDO regulator is a DC linear voltage regulator that can regulate the magnitude of the output voltage even when the supply voltage is very close to the output voltage. In this research paper, various building blocks of a CMOS-based low-dropout voltage regulator were designed and simulated using Multisim LIVE, an online circuit simulator. All of the building blocks were then combined to form the device. Based on the results of the simulation, several spesifications of the LDO were determined. Those are the LDO’s dropout voltage, its quiescent current, its load regulation, and its line regulation. At the end of the design process, during testing it can be shown that this LDO resulted in a dropout voltage of magnitude 200 mV at 200 mA load current which is quite a low dropout voltage. The design has a quiescent current of magnitude 300 , a load regulation of magnitude , and a line regulation of magnitude .

An Ultra-low Power Off Chip Capacitor-less LDO With High Transient Response

This paper presents a low-dropout linear regulator (LDO) with ultra-low power high transient response. This LDO adopts GAP-dynamic-bias circuit to achieve quiescent current as low as 242nA under 0-20mA load. A transient enhancement circuit based on window comparator is used to sense the output voltage change and further enhance the transient response. The circuit is designed and implemented using TSMC0.18um technology, and is verified by simulation using Spectre software. The simulation results show that when the load changes in the range of 10uA-20mA with a 1ns transition edge, the slowest overshoot and undershoot recovery times are only 2.36us and 2.15us. In the input voltage range of 2.5-3.6V, the linear regulation rate and load regulation rate are 0.479mV/V and 2.61nv/mA, respectively.

CMOS Low-Dropout Voltage Regulator Design Trends: An Overview

Systems-on-Chip’s (SoC) design complexity demands a high-performance linear regulator architecture to maintain a stable operation for the efficient power management of today’s devices. Over the decades, the low-dropout (LDO) voltage regulator design has gained attention due to its design scalability with better performance in various application domains. Industry professionals as well as academia have put forward their innovations such as event-driven explicit time-coding, exponential-ratio array, switched RC bandgap reference circuit, etc., to make a trade-off between several performance parameters such as die area, ripple rejection, supply voltage range, and current efficiency. However, current LDO architectures in micro and nanometer complementary metal–oxide–semiconductor (CMOS) technology face some challenges, such as short channel effects, gate leakage, fabrication difficulty, and sensitivity to process variations at nanoscale. This review presents the LDO architectures, optimization techniques, and performance comparisons in different LDO design domains such as digital, analog, and hybrid. In this review, various state-of-the-art circuit topologies, deployed for the betterment of LDO performance and focusing on the specific parameter up-gradation to the overall improvement of the functionality, are framed, which will serve as a comparative study and reference for researchers.

Nonlinear optimal control for Maglev platform roll motion

The stable manifold method is applied to construct a nonlinear real-time feedback optimal control system for the roll motion and vertical position of a certain maglev platform. The chosen platform uses combined electromagnetic suspensions consisting of permanent magnets and upper and lower electromagnets. Within the given technical gaps between the platform and guideway, the magnetic forces provide highly nonlinear effects. This makes this object a multi-input multi-output (MIMO) nonlinear control system. The stable manifold method is applied to construct an optimal nonlinear stabilizing controller. The benefit of the nonlinear control in comparison with a linear regulator is illustrated on an ensemble of perturbed motions caused by a set of initial deviations covering the necessary engineering stabilization range.

Automotive Switched-Capacitor DC–DC Converter With High BW Power Mirror and Dual Supply Driver

This paper presents circuit topologies and implementations for SC DC-DC converters with controlled charging current. It focuses on the power current mirror that regulates the charging current of the flying capacitor and on the switch drivers. The bandwidth and transient response of the power mirror are improved by inserting an auxiliary current mirror in its input signal path. Conventional switch drivers need power supplies with fast response to load transients; the driver presented here is less demanding, as only its core is biased internally, while the output stage is supplied directly by the converter input voltage. The circuit has an additional &#x201C;Linear Regulator&#x201D; mode of operation, whereby the power mirror is turned into a pass transistor. This expands the low-end limit of the converter input voltage. These solutions were used to design in a 130nm BCD technology an automotive SC DC-DC converter. Simulations and measurements performed over the entire automotive temperature range (&#x2212;40C to &#x002B;150C), for supply voltages between 8V and 28V, demonstrate that the converter meets all requirements: it can operate with output capacitors as small as <inline-formula> <tex-math notation="LaTeX">$1\mu \text{F}$ </tex-math></inline-formula>; it provides regulated 5V output voltage for load currents up to 200mA, ensuring a low output voltage ripple, of 35mV and 9mV for output capacitors of <inline-formula> <tex-math notation="LaTeX">$1\mu \text{F}$ </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">$10\mu \text{F}$ </tex-math></inline-formula>, respectively; its efficiency peaks at 81.3&#x0025; for the typical battery voltage level, 12V.

Failure Region Estimation of Linear Voltage Regulator using Model-based Virtual Sensing and Non-invasive Stability Measurement

Voltage regulator (VR) stability plays an essential role in ensuring maximum power delivery and long-lasting electronic lifespan. Capacitor with a specific equivalent series resistance (ESR) range is typically connected at the VR output terminal to compensate for instability of the VR due to sudden changes in load current. The stability of VR can be measured by analyzing output voltage during load transient tests. However, the optimum ESR range obtained from the ESR tunnel graph in its datasheet can only be characterized by testing a set of data points consisting of ESR and load currents. Characterization process is performed manually by changing the value of ESR and load current for each operating point. However, the inefficient process of estimating the critical value of ESR must be improved given that it requires a large amount of time and expertise. Furthermore, the stability analysis is currently conducted on the basis of the number of oscillation counts of VR output voltage signal. Therefore, a model-based virtual sensing approach that mainly focuses on black-box modeling through system identification method and training neural network on the basis of estimated transfer function coefficients is introduced in this study. The proposed approach is used to estimate the internal model of the VR and reduce the number of data points that need to be acquired. In addition, the VR stability is analyzed using noninvasive stability measurement method, which can measure phase margin from the frequency response of the VR circuit in closed-loop conditions. Results showed that the proposed method reduces the time it takes to produce an ESR tunnel graph by 84% with reasonable accuracy (MSE of 5×10−6, RMSE of 2.24×10−3, MAE of 1×10−3, and R2 of 0.99). Therefore, efficiency and effectiveness of ESR characterization and stability analysis of the VR circuit is improved.

A Nonlinear SRM Controller Design for Torque Ripple Reduction with accounting for Magnetic Saturation

In this paper, a nonlinear backstepping controller design is proposed for torque ripple minimization in switched reluctance motor (SRM) drive systems, which ensures less acoustic noise and less vibration. The proposed controller is based on a model taking into account the stator coils magnetic saturation phenomenon. For the torque ripple optimization purpose, the excitation angles are adapted according to the instantaneous SRM torque and speed values. Therefore, a lookup table is built, proposing the excitation angles optimal values for different machine operation points. The proposed control strategy validation was carried out by simulation, using MATLAB-Simulink tools. More specifically, the Simpower system library was exploited, since it offers an SRM simulator, taking into account magnetic saturation. To highlight the supremacy of the proposed controller, its performances are compared with those of conventional linear (PI) regulator. The obtained results validate the proposed controller robustness and efficiency.

Regional Eigenvalue Assignment in Cooperative Linear Output Regulation

The contribution of this paper is a regional eigenvalue assignment method for cooperative output regulation of heterogeneous linear multiagent systems with an internal model-based distributed dynamic state feedback control law. The proposed method offers an agent-wise local approach to synthesize distributed control gains while assigning, for example, the minimal decay rate and the minimal damping ratio of the overall closed-loop system as desired. Numerical examples demonstrate the efficacy of the proposed method by assigning the eigenvalues of a large-scale system to different regions, specifically, disks, shifted half-planes, and conic sectors.