Controlled Buck Converter Research Articles

A new artificial ecosystem-based optimization integrated with Nelder-Mead method for PID controller design of buck converter

Over the last decade, there has been a constant development in control techniques for DC-DC power converters which can be classified as linear and nonlinear. Researchers focus on obtaining maximum efficiency using linear control techniques to avoid complexity although nonlinear control techniques may achieve full dynamic capabilities of the converter. This paper has a similar purpose in which a novel hybrid metaheuristic optimization algorithm (AEONM) is proposed to design an optimal PID controller for DC-DC buck converter’s output voltage regulation. The AEONM employs artificial ecosystem-based optimization (AEO) algorithm with Nelder-Mead (NM) simplex method to ensure optimal PID controller parameters are efficiently tuned to control output voltage of the buck converter. Initial evaluations are performed on benchmark functions. Then, the performance of AEONM-based PID is validated through comparative results of statistical boxplot, non-parametric test, transient response, frequency response, time-domain integral-error-performance indices, disturbance rejection and robustness using AEO, particle swarm optimization and differential evolution. A comparative performance analysis of transient and frequency responses is also performed against simulated annealing, whale optimization and genetic algorithms for further performance assessment. The comparisons have shown the proposed hybrid AEONM algorithm to be superior in terms of enhancing the buck converter’s transient and frequency responses.

Implementation of Fuzzy Logic Controller for DC DC step Down Converter

This paper presents the design of a Fuzzy logic controller for a DC-DC step-down converter. Buck converters are step-down regulated converters which convert the DC voltage into a lower level standardized DC voltage. The buck converters are used in solar chargers, battery chargers, quadcopters, industrial and traction motor controllers in automobile industries etc. The major drawback in buck converter is that when input voltage and load change, the output voltage also changes which reduces the overall efficiency of the Buck converter. So here we are using a fuzzy logic controller which responds quickly for perturbations, compared to a linear controllers like P, PI, PID controllers. The Fuzzy logic controllers have become popular in designing control application like washing machine, transmission control, because of their simplicity, low cost and adaptability to complex systems without mathematical modeling So we are implementing a fuzzy logic controller for buck converter which maintains fixed output voltage even when there are fluctuations in supply voltage and load. The fuzzy logic controller for the DC-DC Buck converter is simulated using MATLAB SIMULINK. The proposed approach is implemented on DC-DC step down converter for an input of 230V and we get the desired output for variations in load or references. This proposed system increases the overall efficiency of the buck converter.

Design and Tuning of Digital Fractional-Order PID Controller for Permanent Magnet DC Motor

One of the central problems in control theory is related to the design of controllers for the improvement of system performance. The aim of this paper is to design an efficient digital fractional-order proportional-integral-derivative (FO-PID) controller for the speed control of buck converter fed permanent magnet DC (PMDC) motor. Speed control is achieved by a pulse width modulated control. The FO-PID controller parameters (gain and order) are obtained by using the ant colony optimization (ACO) technique. The effectiveness of the proposed control scheme is simulated and verified using MATLAB/Simulink results. The performance comparison shows that the speed control of buck converter fed PMDC motor is improved with proposed FO-PID controller than that of integer-order PID controller.

A comparative study among PID structures applied on a Buck converter control

In this work, a state-space model and control of a DC-DC Buck converter, considering a continuous operating, are presented. A PID controller is considered in the strategy, that considers a low pass filter in the derivative term. The proposed model is validated by comparing it with a switched model. The PID gains are obtained by the Ziegler-Nichols method. In order to improve the system’s performance considering an environment containing high-frequency noises, the modified PID controller is implemented with several configurations.

An EGA Approach-Based Fractional Order PID Controller for Synchronous Buck Converters

In this paper, an enhanced genetic algorithm (EGA) technique-based fractional order PID controller (FOPID) for simultaneous control of synchronous buck converters is proposed. The novelty of EGA method is that enhancement process is done by the Rat swarm algorithm (RSA). The computational scheme of RSA is used to enhance the performance of traditional genetic algorithm (GA) and a modified version of GA, which is used for optimal tuning of FOPID controller. In the proposed methodology, the FOPID controller gain is adjusted to achieve the preferred response that is demonstrated by EGA technique. The objective of the proposed technique is “the smooth DC output voltage is attained under damped response”. The proposed control method is executed and simulated in MATLAB platform and the performance is analyzed with the existing methods. Statistical analysis of mean, median and standard deviation for the proposed and existing methods is also analyzed. The proposed FOPID controller produces regulated output DC voltage having 34% lesser overshoots and two times faster settling time when compared to the existing dynamic evolution controller for Synchronous Buck Converters (SBCs). The designed optimal FOPID controlled SBC is also implemented in hardware using Atmega16A processor for different loading conditions for better applications.

Design a novel digital sliding mode predictive control for buck converter

ABSTRACT In this article, a new discrete-time sliding mode predictive control (DSMPC) with a PID sliding function is proposed for synchronous DC–DC buck converter, and its stability analysis is reported. The model predictive control, along with digital sliding mode control (DSMC), is able to further reducing the chattering phenomenon, steady-state error, overshoot and undershoot. The proposed control implementation only requires output error voltage evaluation. The effectiveness of the proposed DSMPC is proved through simulation results executed by the MATLAB/SIMULINK software. These results demonstrate its superior performance to DSMC. In other words, it represents a significant reduction of the chattering, overshoot and undershoots of output voltage response by an optimised control law during load and line variations. The proposed DSMPC almost overcomes the steady-state error (0.02%) and decreases the ripple value to about 0.2%. The overshoot and undershoot are 1.5% and 1%, respectively. Moreover, when the input voltage is changed by 26%, there is approximately no overshoot and undershoot. Also, some experimental results are presented to further illustrate the effectiveness of the proposed system. Experimental studies have been performed using a Spartan-6 field programmable gate array platform by Xilinx for the implementation of the digital control and relevant logic.

Design of PID Controller Based on ELM and Its Implementation for Buck Converters

Buck converter is a kind of converter device with high efficiency, wide adjustable output voltage, small loss, small size and light weight. Its circuit has nonlinearity and will exhibit abundant nonlinear phenomena with the change of circuit parameters, resulting in unstable output voltage and being susceptible to load and external disturbances. Therefore, a control method based on Extreme Learning Machine (ELM) combined with a proportionalintegral-derivative (PID) controller is proposed in this paper and used for output voltage control of buck converter. Firstly, the mathematical model of buck converter in Continuous Conduction Mode (CCM) is established by the state space averaging method. Then the PID tuning algorithm is designed in combination with ELM, and the stability analysis of the model is carried out. Finally, the simulation experiment is carried out under different disturbances. By comparing with the open-loop control strategy, the effectiveness of the proposed ELM-PID control strategy is verified, indicating that the proposed method can achieve the stability of output voltage and good dynamic response.

Design, Simulation and Application of Buck Converter with Digital PI Controller

In this paper, a dc-dc buck converter with digital PI-controlled is analyzed and designed considering all design parameters such as inductance current variation, output voltage ripple etc. The designed dc-dc buck converter provides stable output voltage against to load changes and output voltage variations. Buck converter control method relies on voltage mode controlled PWM (Pulse width Modulation) with digital PI (Proportional Integral) controller. The design criteria, operating mode selection, suitable material selection, etc. of low cost and high-performance buck converter are explained in detail. Finally, the designed converter is carried out experimentally and the experimental results shows the effectiveness of designed converter under different load profiles.

A Frequency Stable On-Time Control Buck Converter With Reference and Frequency Compensation Technique Using Low ESR Output Capacitor

Two issues plaguing the on-time control dc–dc buck converter are the system instability caused by low equivalent series resistance (ESR) output capacitor and the great variation on switching frequency caused by input/output voltage and load current. Without additional external components or integrated clock-controlled circuits and RC filters, the reference and frequency compensation (RFC) technique is presented in this article to stabilize the converter and eliminate its switching frequency variation issue with a low ESR output capacitor. The proposed frequency-stable on-time control buck converter with input voltage ranging from 4.5 to 30 V and output load ranging up to 6 A was fabricated using a standard 0.25- <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> m BCD (BiCMOS/DMOS) process. With a low ESR ceramic output capacitor, the experimental results show that the converter functions properly and stably over the whole load range, and the switching frequency variation with load current is constrained to 3.8 kHz/A, which is a fairly constant value. Moreover, the peak efficiency of the converter is about 98% and the load transient response is also shown excellent performance with the load stepping from 0.1 to 6 A.

Design and Experimental Validation of PID Controller for Buck Converter: A Multi-Objective Evolutionary Algorithms Based Approach

The buck converter is one of the DC/DC converters that are often used as power supplies and high energy conversion. These controllers are used in electronic devices to regulate the output voltage against change in the input voltage and load current. This leads to the requirement of an efficient control methodology to meet real-time demand. It is found in many works of literature that satisfactory performance in buck converter’s dynamic behavior using genetic algorithm controlling techniques, but the appearance of the transient with large overshoots and the ripple output voltage is not focused. The main reason for such a problem is the improper selection of capacitance values. In this work, to address such issues, along with the PID controller gain values and capacitance selection also be considered in multi-objective problems. The optimization is carried out using the NSGA-II and modified NSGA-II algorithm. This paper also presents a comparison of these algorithms’ performance in terms of time-domain specifications and ripple voltage. Simulated outputs exhibit that the controller based on MNSGA-II for buck converter gives better performance than NSGA-II-based controller and results compared with the existing wok. The MNSGA–II-based PID controller for buck converted validated in the real-time environment also.

A discrete repetitive adaptive sliding mode control for DC-DC buck converter

The problem of sensitivity to uncertainties and disturbances is still a challenging task in the theory of discrete sliding mode controller. In this article, a discrete repetitive adaptive sliding mode control using only input-output measurements of linear time-varying system with periodic disturbances is proposed. A new indirect adaptive algorithm taken into account the periodicity of disturbances is used to identify parameter variations of the considered system. Based on this identification, discrete sliding mode controller is developed. Then, the structure of plug-in repetitive control is integrated into the previous controller to reject harmonic disturbances. A robustness analysis is achieved to ensure the asymptotic stability of the proposed controller. An example of time-varying DC-DC buck converter subject to harmonic disturbances is carried out to illustrate the effectiveness of the designed discrete repetitive adaptive sliding mode control.

Model predictive control of double-input buck converters

The control system of a multiple-input dc–dc converter should ensure the stability of output voltage and reasonably distribute the power of multiple-input voltage sources. In addition, there is mutual coupling between multiple closed control loops, which makes the design of the control system difficult. Based on the ability of model predictive control (MPC) to deal with constraints explicitly, a model predictive control algorithm based on the state-space averaging method is proposed for a double-input buck converter. First, a state-space averaging model of a double-input buck converter is established. Then, considering the power management of two input power supplies, a model predictive controller is designed based on the model by combining the input constraints with the objective function. Both simulation and experimental results show that the system has good steady-state accuracy and fast dynamic response characteristics under the action of model predictive controller.

Output-Voltage-Tracking Control for Buck Converters Using Variable Convergence Rate Mechanism Without Current Feedback

This article aims to accomplish the output voltage tracking task for buck converters without current feedback, diminishing the performance degradation from model-plant mismatches and load variations. The following contributions overcome these difficulties: a) the combination of Luenberger and disturbance observer (DOB) techniques for a parameter-independent voltage-derivative observer; b) the pole-zero cancellation control incorporating the DOB and active-damping injection techniques; and c) the exponential convergence guarantee to the target tracking system subject to the variable convergence rate mechanism. Convincing experimental evidence confirms the effectiveness of proposed tracking control using a prototype 3 kW buck converter control system.

Linear Observer Based Linearizing Control of DC-DC Buck Converter

In this article; we process DC-DC buck converter by linearizing control (non linear control INPUTOUTPUT). As one observes at the same time the inductor current not measurable by a linear state observer proposed. This method can control the system by varying the output voltages, input voltage and load resistance. The proposed method has a stable response capable of reaching the model reference smoothly.

Adaptive Global Sliding Mode Controller Design for Perturbed DC-DC Buck Converters

This paper proposes a novel adaptive intelligent global sliding mode control for the tracking control of a DC-DC buck converter with time-varying uncertainties/disturbances. The proposed control law is formulated using a switching surface that eliminates the reaching phase and ensures the existence of the sliding action from the start. The control law is derived based on the Lyapunov stability theory. The effectiveness of the proposed approach is illustrated via high-fidelity simulations by means of Simscape simulation environment in MATLAB. Satisfactory tracking accuracy, efficient suppression of the chattering phenomenon in the control input, and high robustness against uncertainties/disturbances are among the attributes of the proposed control approach.

A Fast-Response RBAOT-Controlled Buck Converter With Pseudofixed Switching Frequency and Enhanced Output Accuracy

A ripple-based constant on-time (RBCOT) control scheme is excellent in achieving fast transient response during the load current step. However, it suffers from severe electromagnetic interference (EMI) noise and inherent output voltage offset problem. A monolithic ripple-based adaptive on-time (RBAOT)-controlled buck converter is presented to overcome both drawbacks while retaining the advantage of RBCOT. The on-time is adjusted adaptively by detecting the switching node voltage, and thereby ensuring a pseudofixed switching frequency in a steady state, regardless of the input, output voltage, and load current conditions. A correction voltage generated by a coefficient in a virtual inductor current (VIC) circuit is introduced to counteract the offset voltage and enhance the output accuracy. The proposed scheme is simple to implement and suitable for high-conversion ratio applications. Experimental results show that the switching frequency is centered at 1 MHz with less than 6% variation for an output of 5 V and inputs ranging from 8 to 18 V. The output offset voltage is reduced from 16 to 1 mV for an 18 to 1.05-V conversion. For a load current step of 1 A, the output can be settled within <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$6~\mu \text{s}$ </tex-math></inline-formula> and the undershoot and overshoot voltages are controlled to be within 20 mV.

System uncertainties estimation based adaptive robust backstepping control for DC DC buck converter

This paper proposed a novel adaptive robust backstepping control scheme for DC-DC buck converter subjected to external disturbance and system uncertainty. Uncertainty in the load resistance and the input voltage represent the big challenge in buck converter control. In this work, an adaptive estimator for matched and mismatched uncertainties based backstepping control is applied for DC-DC buck converter. The updating laws are determined based on the lyapunov theorem. Thus, the difference between the estimated parameters and actual parameters converges to zero. The proposed control method is compared with the conventional sliding mode control and integral sliding mode control. Simulation results demonstrate the effectiveness and robustness of the proposed controller.

Simplifying ADRC design with error-based framework: case study of a DC–DC buck power converter

In this work, the problem of designing a robust control algorithm for a DC-DC buck power converter is investigated. The applied solution is based on a recently proposed error-based version of the active disturbance rejection control (ADRC) scheme, in which the unknown higher-order terms of the reference signal are treated as additional components of the system “total disturbance”. The motivation here is to provide a practical following of a reference voltage trajectory for the buck converter in specific cases where neither the analytical form of the desired signal nor its future values are known a’priori, hence cannot be directly used for control synthesis. In this work, the application of the error-based ADRC results in a practically appealing control technique, with compact structure, simplified control rule, and intuitive tuning (inherited from the conventional output-based ADRC scheme). Theoretical, numerical, and experimental results are shown to validate the efficacy of the error-based ADRC in buck converter control, followed by a discussion about the revealed theoretical and practical limitations of this approach.

Data-driven disturbance observer-based control: an active disturbance rejection approach

In this paper, a data-driven method for disturbance estimation and rejection is presented. The proposed approach is divided into two stages: an inner stabilization loop, to set the desired reference model, together with an outer loop for disturbance estimation and compensation. Inspired by the active disturbance rejection control framework, the exogenous and endogenous disturbances are lumped into a total disturbance signal. This signal is estimated using an on-line algorithm based on a data-driven predictor scheme, whose parameters are chosen to satisfy high robustness-performance criteria. The above process is presented as a novel enhancement to design a disturbance observer, which constitutes the main contribution of the paper. In addition, the control strategy is completely presented in discrete time, avoiding the use of discretization methods for its digital implementation. As a case study, the voltage control of a DC-DC synchronous buck converter affected by disturbances in the input voltage and the load is considered. Finally, experimental results that validate the proposed strategy and some comparisons with the classical disturbance observer-based control are presented.

A Jitter Amplification Phenomenon in Multisampled Digital Control of Power Converters

This article investigates a nonlinear phenomenon related to multisampling control of power converters. The nonlinearity, manifested as increased gain regions in static modulator transcharacteristic, is caused by the discontinuity of the modulating waveform and can result in increased jittering of the duty cycle. This article proposes a statistical model for predicting the jittering impact on the duty-cycle variance, analytic derivations for the jittering conditions, and an antijittering algorithm. A numerically obtained static modulator transcharacteristic is given to illustrate the increased gain regions. Verifications, performed on a multisampled digitally controlled buck converter, show a good match between the theoretical analysis, simulation, and experimental results. This article is accompanied by videos demonstrating the jitter amplification and the algorithm operation.