Control Of DC-DC Converter Research Articles

PWM-Based Sliding Mode Controller for Three-Level Full-Bridge DC-DC Converter that Eliminates Static Output Voltage Error

This paper proposes a pulse width modulation (PWM)-based sliding mode controller (SMC) for a full-bridge DC-DC converter that can eliminate static output voltage error. Hysteretic SMC in DC-DC converter does not have a fixed switching frequency, and applying hysteretic SMC to full-bridge converters is difficult. Fixed-frequency SMC, which is also called PWM-based SMC, based on equivalent control overcomes these shortcomings. However, the controller order reduction in equivalent control in PWM-based SMC causes static output voltage error. To resolve this issue, an integral item is added to the PWM-based SMC. Sliding mode coefficients are designed by applying a standard second-order system to the sliding mode surface. The effect of adding an integral item on the controller is analyzed, and an integral coefficient design method is proposed. Experiment results on a three-level full-bridge DC-DC converter verify the control scheme and design method proposed in this paper.

Solar Photovoltaic Powered Sailing Boat Using Buck Converter

<p>The main objective of this paper is to establish technical and economical aspects of the application of stand-alone photovoltaic (PV) system in sailing boat using a buck converter in order to enhance the power generation and also to minimize the cost. Performance and control of dc-dc converter, suitable for photovoltaic (PV) applications, is presented here. A buck converter is employed here which extracts complete power from the PV source and feeds into the dc load. The power, which is fed into the load, is sufficient to drive a boat . With the help of matlab simulink software PV module and buck model has been designed and simulated and also compared with theoretical predictions.</p>

A 12-bit Hybrid Digital Pulse Width Modulator

In this paper, a 12-bit high resolution, power and area efficiency hybrid digital pulse width modulator (DPWM) with process and temperature (PT) calibration has been proposed for digital controlled DC-DC converters. The hybrid structure of DPWM combines a 6-bit differential tapped delay line ring-mux digital-to-time converter (DTC) schema and a 6-bit counter-comparator DTC schema, resulting in a power and area saving solution. Furthermore, since the 6-bit differential delay line ring oscillator serves as the clock to the high 6-bit counter-comparator DTC, a high frequency clock is eliminated, and the power is significantly saved. In order to have a simple delay cell and flexible delay time controllability, a voltage controlled inverter is adopted to build the deferential delay cell, which allows fine-tuning of the delay time. The PT calibration circuit is composed of process and temperature monitors, two 2-bit flash ADCs and a lookup table. The monitor circuits sense the PT (Process and Temperature) variations, and the flash ADC converts the data into a digital code. The complete circuits design has been verified under different corners of CMOS 0.18um process technology node.

English

This paper presents a elimination of voltage steady-state error and achieve high-accuracy current estimation without using current sensor. The elimination of voltage steady-state error and achieve high-accuracy current estimation purpose using comprehensive compensation strategy. This comprehensive compensation strategy algorithm cannot effectively eliminate the output voltage steady-state error, so fuzzy logic controller is implemented. A digital current-mode controller for dc-dc converters is introduced.The current control mode proposed current observer and PCC algorithm. It achieves the highest observation accuracy by compensating for all the known parasitic parameter. By employing the optimal current observer-based predictive current controller, a boost converter is implemented. The current-mode loop is sensorless, relying on constants and internal loop states. Fast current-mode control mechanism is implemented. This control scheme is that it facilitates the application of a low resolution PWM.

Maximum Power Point Controller for Thermoelectric Generators to Support a Vehicle Power Supply

The growing mobility increases the world-wide fuel consumption. Yet the amount of fossil fuel is limited and the environmental burden is increasing dramatically as well. Many governments have enacted laws to regulate and reduce the fuel consumption as well as the CO2 emissions of combustion engines. An idea to save fuel and to reduce the environmental burden is to use thermoelectric generators (TEGs) to recover the waste heat of the exhaust gas and convert into electric energy in automotive applications. For the linking of TEGs to the vehicle is power supply, a DC-DC converter can be used. To support a widerange of TEGs with different electric parameters, the control of DC-DC converter must be robust. Further, the control should track the maximum power point (MPP) of the TEG for an efficient power recovery. This paper presents a digital cascade controller for a boost-buck converter that charges a vehicle battery and supplies the load. To model and analyze the discontinuous converter, the state-space-averaging (SSA) is used. The tracking of the MPP is realized with a gradient algorithm and an input current control. An adaptive step size algorithm reduces the conversion time of the maximum power point tracking algorithm (MPPT). Experiments verified the controller design and the efficiency of the MPPT.

Performance Analysis of Controller Design for DC-DC Buck Converter Using Linear and Non Linear Technique

The switched mode dc-dc converters are some of the most widely used power electronics circuits because of high conversion efficiency and flexible output voltage. Many methods have been developed for the control of dc-dc converters. This paper deals with design of controller for dc-dc buck converter using various control techniques. The first two control techniques are based on classical or linear control methods i.e. PI and PID control, while the other two control technique are based on non linear control method i.e. Sliding Mode Control (SMC) and Sliding Mode Proportional Integral Derivative Control (SMC-PID). The output voltage and the inductor current of the applied control techniques are analyzed and compared in transient and steady state region. Also the robustness of the buck converter system is tested for load changes and input voltage variations. Matlab/Simulink is used for the simulations. The detailed simulation results are presented, which compare the performance of the designed controllers for various cases. The results show that the non linear control for DC/DC Buck converter proves to be more robust than linear control especially when dynamic tests are applied.

Digital Fast P Slow ID Control DC–DC Converter Using A–D Converters in Different Resolutions

The purpose of this paper is to present a digital fast P and slow ID control dc-dc converter using A-D converters in different resolutions. In the proposed method, the operation parts are divided into the P control and the ID control. Moreover, the high-speed and low resolution A-D converter is set for the P control, and the very low-speed and high resolution one is set for the ID control. In the transient response experiment, the convergence time is improved by about 77% compared with the conventional PID control method. As a result, it is possible to achieve the low cost design with keeping the superior transient response.

New Generation Solar PV Powered Sailing Boat using Boost Chopper

The objective of this paper is to establish technical and economical aspects of the application of stand-alone photovoltaic (PV) system in sailing boat using boost chopper in order to simplify the power system and minimize the cost. Performance and control of dc-dc converter, suitable for photovoltaic (PV) applications, is presented here. This converter is mainly boost converter feeding a dc load. However, for integration purpose only one inductor is sufficient for power conversion in the converter. Here, the boost converter extracts complete power from the PV source and feeds into the load. Furthermore, the PV panel provides the essential protection to the passengers of boat from the straight sunshine and also from the rainwater.

Modeling and implementation of fixed switching frequency sliding mode control to two-stage DC-DC converter

A fixed switching frequency sliding mode (FSFSM) controller for two-stage DC-DC converter is proposed. Owing to the time-varying switched mode operation, the dynamic performance of two-stage converter becomes high order and non-linear. For designing the FSFSM controller, the state-space average model is made, and then the three conditions of sliding mode (SM) control, namely, hitting, existence and stability condition are analyzed. A conventional linear controller (Lag) for two-stage converter is designed as a comparison to validate the good robustness and dynamic response of the FSFSM controller. At last, a series of simulation and experimental results are presented to demonstrate the feasibility of the designed FSFSM controller.

Digital Control of DC-DC Converters Employing Wide Band Gap (WBG) Power Devices

DC-DC converters are used at the Advanced Photon Source (APS) at Argonne National Laboratory to power electromagnets. The electromagnets guide the photon beams, therefore the control system of the DC-DC converters should be highly accurate to provide minimum spatial spread of the beam. Currently the converters have all been regulated by analog control systems. An upgrade to digital control system is being evaluated to resolve the aging and obsolescence issues. This paper describes the design and evaluation of a digital control system to regulate the output current and reduce noise coupled in the system. A digital controller is first designed based on the small signal model of the converter. Experimental data of the output current is analyzed. Digital filters are then designed to reduce the noise in the output current. The complete control system is then simulated and results are evaluated. Wide Band Gap (WBG) power devices enable the development of smaller and more durable power converters with higher performance and less power consumptions than traditional silicon devices. Performance of the digital controlled DC-DC converters using WBG power switching devices including silicon carbide (SiC) power MOSFETs and gallium nitride (GaN) power transistorswill be evaluated, in comparison with the converters using traditional silicon power switching devices.

An Intelligent Algorithm based Controller for Multiple Output DC-DC Converters with Voltage Mode Weighting Factor

Multiple output DC-DC converters are widely used in many applications such as aerospace, industrial and medical equipments. The purpose of this paper is to present an intelligent control system for the multiple output DC-DC converters. In order to perform this purpose, a double ended forward DC-DC converter with three output voltages (+5 V/ 50W, +15 V/ 45W and -15 V/ 15W) is considered and analyzed. The voltage mode weighting factor control system with Genetic Algorithm (GA) is performed on the considered DC-DC converter. Furthermore, a PID controller is utilized to minimize the total steady state error. The stability proofs of the system in presence of PID Controller have been analyzed. The results show that the GA weighting factors estimator improves the cross and output regulations in multiple output DC-DC converters. Simulation results verify and confirm the truth and accuracy of the proposed method

Modeling and Control of Solid Oxide Fuel Cell Generation System Integrated in Microgrid

This paper presents a control strategy of solid oxide fuel cell (SOFC) generation system integrated into microgrid. To enhance the dynamic response of SOFC, storage battery is paralleled via a DC bus, and the hysteretic control of bi-directional DC-DC converter is adopted. The common DC-AC inverter adopts an improved droop control. The active synchronization control is applied to ensure the smooth mode transition of microgrid. The simulation results show the dynamic performance of SOFC generation system in different operation modes.

Design for Boost DC-DC Converter Controller Based on State-Space Average Method

In the process of designing high performance switch power, need to establish the accurate mathematical model of converter. The DC/DC converter generally has the characteristics of nonlinear, multimodal, time-varying, so need to use new methods to study it. The work of this paper aimed at non isolated DC / DC converter, established the mathematical model of Boost converter circuit by using the state space average method. Then design the closed-loop PI controller based on the Boost converter model, the closed-loop system has good static and dynamic performance, to meet the requirements of use.

An optimal current observer for predictive current controlled buck DC-DC converters.

In digital current mode controlled DC-DC converters, conventional current sensors might not provide isolation at a minimized price, power loss and size. Therefore, a current observer which can be realized based on the digital circuit itself, is a possible substitute. However, the observed current may diverge due to the parasitic resistors and the forward conduction voltage of the diode. Moreover, the divergence of the observed current will cause steady state errors in the output voltage. In this paper, an optimal current observer is proposed. It achieves the highest observation accuracy by compensating for all the known parasitic parameters. By employing the optimal current observer-based predictive current controller, a buck converter is implemented. The converter has a convergently and accurately observed inductor current, and shows preferable transient response than the conventional voltage mode controlled converter. Besides, costs, power loss and size are minimized since the strategy requires no additional hardware for current sensing. The effectiveness of the proposed optimal current observer is demonstrated experimentally.

A Model Predictive Control Method for Bidirectional DC-DC Converter in the ZVS Condition

The bidirectional DC-DC converter can achieve energy storage and transfer by adjusting the magnitude and direction of the current, which is widely used in the DC interconnect micro-grid system and battery energy management system. In the current tracking control of the bidirectional DC-DC converter, the switching loss can be significantly reduced under the Zero Voltage Switching (ZVS) condition. In this situation, the paper firstly establishes the model of switching progress. Considering the ZVS constraints, the model can be described as piecewise linear equations. Secondly, based on the piecewise model, the model predictive controller is constructed. By solving a constrained optimal problem, the switching time forecast in the ZVS condition is obtained to realize the current tracking. Moreover, the derivation of boundary conditions is presented. Finally, a simulation is presented to validate the proposed model and control method.

Predictive Trailing Triangle Modulation Peak Current Control in DC-DC Converters

Predictive digital peak current control (PDPCC) in dc/dc converters using trailing triangle modulation (TTM) is analyzed in detail. The recurrence duty cycle relationship is derived and based on it stability analysis is carried out. It is proved instability is encountered on the whole range of the duty cycle and therefore peak current control using trailing triangle modulation, even proposed and mentioned in some publications, is unusable The analysis is performed in a general manner, in the sense it is converter topology independent. The theoretical considerations are confirmed for a boost converter, first based on state-space equations using the MATLAB program and finally by circuit simulation using the CASPOC package

Fuzzy Predictive Control of Step-Down DC-DC Converter Based on Hybrid System Approach

In this paper, a fuzzy predictive control scheme is proposed for controlling output voltage of a step-down DC-DC converter in presence of disturbance and uncertainty. The DC-DC converter is considered as a hybrid system and modeled by Mixed Logical Dynamical modeling approach. The main objective of the paper is to design a Fuzzy Predictive Control to achieve desired voltage output without increasing complexity of the hybrid model of DC-DC converter in various conditions. A model predictive control is designed based on the hybrid model and applied to the system. Although the performance of the model predictive control method is satisfactory in normal condition, it suffers from lack of robustness in presence of disturbance and uncertainty. So, to succeed in facing up to the problem a fuzzy supervisor is utilized to adjust the main predictive controller based on the measured states of the system. In this paper it is shown that the proposed fuzzy predictive control scheme has advantages such as simplicity and efficiency in normal operation and robustness in presence of disturbance and uncertainty. Through simulations effectiveness of the proposed method is shown.

Study on the Control Algorithm of Two-Stage DC-DC Converter for Electric Vehicles

The fast response, high efficiency, and good reliability are very important characteristics to electric vehicles (EVs) dc/dc converters. Two-stage dc-dc converter is a kind of dc-dc topologies that can offer those characteristics to EVs. Presently, nonlinear control is an active area of research in the field of the control algorithm of dc-dc converters. However, very few papers research on two-stage converter for EVs. In this paper, a fixed switching frequency sliding mode (FSFSM) controller and double-integral sliding mode (DISM) controller for two-stage dc-dc converter are proposed. And a conventional linear control (lag) is chosen as the comparison. The performances of the proposed FSFSM controller are compared with those obtained by the lag controller. In consequence, the satisfactory simulation and experiment results show that the FSFSM controller is capable of offering good large-signal operations with fast dynamical responses to the converter. At last, some other simulation results are presented to prove that the DISM controller is a promising method for the converter to eliminate the steady-state error.

Modeling, control, and simulation of battery storage photovoltaic-wave energy hybrid renewable power generation systems for island electrification in Malaysia.

Today, the whole world faces a great challenge to overcome the environmental problems related to global energy production. Most of the islands throughout the world depend on fossil fuel importation with respect to energy production. Recent development and research on green energy sources can assure sustainable power supply for the islands. But unpredictable nature and high dependency on weather conditions are the main limitations of renewable energy sources. To overcome this drawback, different renewable sources and converters need to be integrated with each other. This paper proposes a standalone hybrid photovoltaic- (PV-) wave energy conversion system with energy storage. In the proposed hybrid system, control of the bidirectional buck-boost DC-DC converter (BBDC) is used to maintain the constant dc-link voltage. It also accumulates the excess hybrid power in the battery bank and supplies this power to the system load during the shortage of hybrid power. A three-phase complex vector control scheme voltage source inverter (VSI) is used to control the load side voltage in terms of the frequency and voltage amplitude. Based on the simulation results obtained from Matlab/Simulink, it has been found that the overall hybrid framework is capable of working under the variable weather and load conditions.

Switching PI Control for DC-DC Converters Based on Control Performance

Switching PI Control for DC-DC Converters Based on Control Performance