scholarly journals Sensorless Adaptive Voltage Control for Classical DC-DC Converters Feeding Unknown Loads: A Generalized PI Passivity-Based Approach

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6367
Author(s):  
Walter Gil-González ◽  
Oscar Danilo Montoya ◽  
Carlos Restrepo ◽  
Jesus C. Hernández
Keyword(s):  
Control Point ◽  
Voltage Regulation ◽  
Boost Converter ◽  
Second Order ◽  
Buck Converter ◽  
Point Of View ◽  
Linear Estimator ◽  
Resistive Load ◽  
Resistive Loads ◽  
Experimental Validations

The problem of voltage regulation in unknown constant resistive loads is addressed in this paper from the nonlinear control point of view for second-order DC-DC converters. The converters’ topologies analyzed are: (i) buck converter, (ii) boost converter, (iii) buck-boost converter, and (iv) non-inverting buck-boost converter. The averaging modeling method is used to model these converters, representing all these converter topologies with a generalized port-Controlled Hamiltonian (PCH) representation. The PCH representation shows that the second-order DC-DC converters exhibit a general bilinear structure which permits to design of a passivity-based controller with PI actions that ensures the asymptotic stability in the sense of Lyapunov. A linear estimator based on an integral estimator that allows reducing the number of current sensors required in the control implementation stage is used to determine the value of the unknown resistive load. The main advantage of this load estimator is that it ensures exponential convergence to the estimated variable. Numerical simulations and experimental validations show that the PI passivity-based control allows voltage regulation with first-order behavior, while the classical PI controller produces oscillations in the controlled variable, significantly when the load varies.

scholarly journals Fixed Switching Frequency Digital Sliding-Mode Control of DC-DC Power Supplies Loaded by Constant Power Loads with Inrush Current Limitation Capability

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1055 ◽  
Author(s):  
Abdelali El Aroudi ◽  
Blanca Martínez-Treviño ◽  
Enric Vidal-Idiarte ◽  
Angel Cid-Pastor
Keyword(s):  
Sliding Mode ◽  
Voltage Regulation ◽  
Boost Converter ◽  
Switching Frequency ◽  
Inrush Current ◽  
Resistive Load ◽  
Constant Power ◽  
Current Limitation ◽  
Power Load ◽  
Current Limiting

This paper proposes a digital sliding-mode controller for a DC-DC boost converter under constant power-loading conditions. The controller has been designed in two steps: the first step is to reach the sliding-mode regime while ensuring inrush current limiting; and the second one is to move the system to the desired operating point. By imposing sliding-mode regime, the equivalent control and the discrete-time large-signal dynamic model of this system are derived. The analysis shows that unlike with a resistive load, the boost converter under a fixed-frequency digital sliding-mode current control with external voltage loop open and loaded by a constant power load, is unstable. Furthermore, as with a resistive load, the system presents a right-half plane zero in the control-to-output transfer function. After that, an outer controller is designed in the z-domain for system stabilization and output voltage regulation. The results show that the system exhibits good performance in startup in terms of inrush current limiting and in transient response due to load and input voltage disturbances. Numerical simulations from a detailed switched model are in good agreement with the theoretical predictions. An experimental prototype is implemented to verify the mathematical analysis and the numerical simulation, which results in a perfect agreement in small-signal and steady-state behavior but also in a small discrepancy in the current limitation due a small propagation delay. Some efficient solutions have been proposed to mitigate the inrush current in the experimental results.

scholarly journals Analysis and Design for Output Voltage Regulation in Constant-on-Time-Controlled Fly-Buck Converter

Electronics ◽  
2021 ◽  
Vol 10 (16) ◽  
pp. 1886
Author(s):  
Younghoon Cho ◽  
Paul Jang
Keyword(s):  
Output Voltage ◽  
Voltage Regulation ◽  
Design Guidelines ◽  
Buck Converter ◽  
Design Guideline ◽  
Analysis And Design ◽  
Flyback Converter ◽  
Auxiliary Power ◽  
Primary Output ◽  
Output Capacitor

Fly-buck converter is a multi-output converter with the structure of a synchronous buck converter structure on the primary side and a flyback converter structure on the secondary side, and can be utilized in various applications due to its many advantages. In terms of control, the primary side of the fly-buck converter has the same structure as a synchronous buck converter, allowing the constant-on-time (COT) control to be applied to the fly-buck converter. However, due to the inherent energy transfer principle, the primary-side output voltage regulation of COT controlled fly-buck converters may be poor, which can deteriorate the overall converter performance. Therefore, the primary output capacitor must be carefully designed to improve the voltage regulation characteristics. In this paper, a theoretical analysis of the output voltage regulation in COT controlled fly-buck converter is conducted, and based on this, a design guideline for the primary output capacitor considering the output voltage regulation is presented. The validity of the analysis and design guidelines was verified using a 5 W prototype of the COT controlled fly-buck converter for telecommunication auxiliary power supply.

scholarly journals Compensated Single Input Multiple Output Flyback Converter

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3009
Author(s):  
Mohammad Tahan ◽  
David O. Bamgboje ◽  
Tingshu Hu
Keyword(s):  
Transient Response ◽  
Current Mode ◽  
Voltage Regulation ◽  
Buck Converter ◽  
Output Channel ◽  
Flyback Converter ◽  
Input Multiple Output ◽  
Voltage Deviation ◽  
Single Input ◽  
The Cross

A new single-input multiple-output (SIMO) converter is proposed in this work by incorporating flyback and buck converters in a master–slave configuration. The objective of this work is to address the cross regulation problem, achieve tight voltage regulation, improve the circuit form factor and attain a fast transient response for a SIMO flyback converter. The flyback converter maintains the output channels within 10% of their rated voltages and the SIMO buck converter is placed in series with the flyback converter such that it compensates for the output voltage deviation. Moreover, a time multiplexing switching scheme decouples output channel to eliminate the cross-regulation problem and remove the need for an additional winding transformer per each output channel. A type II compensator with a peak current mode controller was designed to achieve faster transient response which is critical for the proposed configuration. A thorough steady-state analysis was carried out on a triple output channel topology to obtain the design criteria and component values. MATLAB/Simscape modelling and simulation was used to validate the effectiveness of the proposed converter with the result yielding satisfactory transience even with load disturbance. Additionally, the result of the proposed converter is compared with previously published works.

Effects of expiratory loading on respiration in humans

1980 ◽  
Vol 49 (4) ◽  
pp. 601-608 ◽  
Author(s):  
B. Gothe ◽  
N. S. Cherniack
Keyword(s):  
Muscle Activity ◽  
Healthy Subjects ◽  
Respiratory Muscle ◽  
Resistive Load ◽  
Similar Magnitude ◽  
Occlusion Pressure ◽  
Ventilatory Responses ◽  
Residual Capacity ◽  
Resistive Loads ◽  
The Difference

We examined the effects of expiratory resistive loads of 10 and 18 cmH2O.l-1.s in healthy subjects on ventilation and occlusion pressure responses to CO2, respiratory muscle electromyogram, pattern of breathing, and thoracoabdominal movements. In addition, we compared ventilation and occlusion pressure responses to CO2 breathing elicited by breathing through an inspiratory resistive load of 10 cmH2O.l-1.s to those produced by an expiratory load of similar magnitude. Both inspiratory and expiratory loads decreased ventilatory responses to CO2 and increased the tidal volume achieved at any given level of ventilation. Depression of ventilatory responses to Co2 was greater with the larger than with the smaller expiratory load, but the decrease was in proportion to the difference in the severity of the loads. Occlusion pressure responses were increased significantly by the inspiratory resistive load but not by the smaller expiratory load. However, occlusion pressure responses to CO2 were significantly larger with the greater expiratory load than control. Increase in occlusion pressure observed could not be explained by changes in functional residual capacity or chemical drive. The larger expiratory load also produced significant increases in electrical activity measured during both inspiration and expiration. These results suggest that sufficiently severe impediments to breathing, even when they are exclusively expiratory, can enhance inspiratory muscle activity in conscious humans.

COMPLEX DYNAMICS AND FAST-SLOW SCALE INSTABILITY IN CURRENT-MODE CONTROLLED BUCK CONVERTER WITH CONSTANT CURRENT LOAD

2013 ◽  
Vol 23 (04) ◽  
pp. 1350062 ◽  
Author(s):  
GUOHUA ZHOU ◽  
BOCHENG BAO ◽  
JIANPING XU
Keyword(s):  
Complex Dynamics ◽  
Period Doubling ◽  
Current Mode ◽  
Input Voltage ◽  
Second Order ◽  
Buck Converter ◽  
Constant Current ◽  
Current Load ◽  
Time Model ◽  
Conduction Mode

The complex dynamics and coexisting fast-slow scale instability in current-mode controlled buck converter with constant current load (CCL), operating in both continuous conduction mode (CCM) and discontinuous conduction mode (DCM), are investigated in this paper. Via cycle-by-cycle computer simulation and experimental measurement of current-mode controlled buck converter with CCL, it is found that a unique fast-slow scale instability exists in the second-order switching converter. It is also found that a unique period-doubling accompanied by Neimark–Sacker bifurcation exists in this simple second-order converter, which is different from period-doubling or Neimark–Sacker bifurcations reported previously. Based on a nonlinear discrete-time model and the corresponding Jacobian, the effects of CCL and input voltage on the dynamics of current-mode controlled buck converter are investigated and verified theoretically. Fixed point analysis for slow-scale low-frequency oscillation is also given to verify the dynamics and the coexisting fast-slow scale instability.

Voltage regulation of buck converter with constant power load: An adaptive power shaping control

2021 ◽  
Vol 115 ◽  
pp. 104891
Author(s):  
Wei He ◽  
Mohammad Masoud Namazi ◽  
Hamid Reza Koofigar ◽  
Mohammad Ali Amirian ◽  
Josep M. Guerrero
Keyword(s):  
Voltage Regulation ◽  
Buck Converter ◽  
Constant Power ◽  
Power Load ◽  
Adaptive Power ◽  
Constant Power Load

A new technique for right half plane zero elimination from dynamics of a boost converter using magnetic coupling concept

Circuit World ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Alireza Goudarzian
Keyword(s):  
Dynamic Response ◽  
Half Plane ◽  
Phase Structure ◽  
Voltage Regulation ◽  
Boost Converter ◽  
Open Loop ◽  
Positive Zero ◽  
Voltage Gain ◽  
Minimum Phase ◽  
Content Type

Purpose Control-signal-to-output-voltage transfer function of the conventional boost converter has at least one right-half plane zero (RHPZ) in the continuous conduction mode which can restrict the open-loop bandwidth of the converter. This problem can complicate the control design for the load voltage regulation and conversely, impact on the stability of the closed-loop system. To remove this positive zero and improve the dynamic performance, this paper aims to suggest a novel boost topology with a step-up voltage gain by developing the circuit diagram of a conventional boost converter. Design/methodology/approach Using a transformer, two different pathways are provided for a classical boost circuit. Hence, the effect of the RHPZ can be easily canceled and the voltage gain can be enhanced which provides conditions for achieving a smaller working duty cycle and reducing the voltage stress of the power switch. Using this technique makes it possible to achieve a good dynamic response compared to the classical boost converter. Findings The observations show that the phase margin of the proposed boost converter can be adequately improved, its bandwidth is largely increased, due to its minimum-phase structure through RHPZ cancellation. It is suitable for fast dynamic response applications such as micro-inverters and fuel cells. Originality/value The introduced method is analytically studied via determining the state-space model and necessary criteria are obtained to achieve a minimum-phase structure. Practical observations of a constructed prototype for the voltage conversion from 24 V to 100 V and various load conditions are shown.

Inspiratory resistive load detection in conscious dogs

1991 ◽  
Vol 70 (3) ◽  
pp. 1284-1289 ◽  
Author(s):  
P. W. Davenport ◽  
D. J. Dalziel ◽  
B. Webb ◽  
J. R. Bellah ◽  
C. J. Vierck
Keyword(s):  
Training Stimulus ◽  
Detection Threshold ◽  
Resistive Load ◽  
Initial Training ◽  
Breathing Patterns ◽  
Physiological Mechanisms ◽  
Mechanical Loads ◽  
Load Detection ◽  
Resistive Loads ◽  
Tracheal Stoma

The physiological mechanisms mediating the detection of mechanical loads are unknown. This is, in part, due to the lack of an animal model of load detection that could be used to investigate specific sensory systems. We used American Foxhounds with tracheal stomata to behaviorally condition the detection of inspiratory occlusion and graded resistive loads. The resistive loads were presented with a loading manifold connected to the inspiratory port of a non-rebreathing valve. The dogs signaled detection of the load by lifting their front paw off a lever. Inspiratory occlusion was used as the initial training stimulus, and the dogs could reliably respond within the first or second inspiratory effort to 100% of the occlusion presentations after 13 trials. Graded resistances that spanned the 50% detection threshold were then presented. The detection threshold resistances (delta R50) were 0.96 and 1.70 cmH2O.l-1.s. Ratios of delta R50 to background resistance were 0.15 and 0.30. The near-threshold resistive loads did not significantly change expired PCO2 or breathing patterns. These results demonstrate that dogs can be conditioned to reliably and specifically signal the detection of graded inspiratory mechanical loads. Inspiration through the tracheal stoma excludes afferents in the upper extrathoracic trachea, larynx, pharynx, nasal passages, and mouth from mediating load detection in these dogs. It is unknown which remaining afferents (vagal or respiratory muscle) are responsible for load detection.

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