Modeling Of DC-DC Converters Research Articles

Full-bridge DC-DC Converter based on Linear Active Disturbance Rejection Control

Dual Active Bridge (DAB) converter has been a research hotspot in recent years. It is widely used in distributed power generation system, DC microgrid system and power management system. Traditional PI controllers do not perform well in the face of nonlinear loads and external disturbances, so a more advanced control method is needed to improve the stability and performance of the system. In this paper, a control strategy based on active disturbance rejection control (ADRC) is proposed to improve the control performance of full-bridge DC-DC converter. First of all, the small signal mathematical model of full-bridge DC-DC converter is established, and the function relationship between input, output, control quantity and disturbance quantity in the system is obtained. Then, the extended state observer of ADRC core module is designed, and its parameters are adjusted and simulated, compared with the traditional PI controller. The simulation results show that the full-bridge DC-DC converter based on LADRC has faster dynamic response and better disturbance immunity, which can effectively improve the stability and robustness of the system.

Development of a Mathematical Model of a Two-stage DC-DC Converter

Development of a Mathematical Model of a Two-stage DC-DC Converter

High-power three-phase interleaved parallel NPC structure DC-DC converter modeling and simulation

Abstract In fields such as DC microgrids, renewable energy generation, and electric vehicle charging stations, three-phase NPC structure DC-DC converters play an irreplaceable role, constituting a significant part of modern power electronics technology. Mathematical models are established based on various operating modes of IGBT switching devices under PWM control, encompassing input voltage, output voltage, phase currents, average current, and duty cycle. Simulation models are constructed on the MATLAB platform to confirm the correctness of these mathematical models. Closed-loop control strategies are implemented using proportional-integral (PI) controllers. This control strategy serves to confirm the precision of the mathematical models.

Sigmoid function model of parallel-connected DC-DC converters and analysis of their dynamic characteristics.

Because of the manufacturing variations of circuit elements and the effects of parasitic parameters, the switching elements of parallel-connected modules cannot be synchronously switched. Consequently, the characteristics of these converters, which are multi-mode, high-order systems, cannot be comprehensively described using reduced-order models based on the symmetry of circuit topology and parameters. It is also difficult to fully describe the characteristics of these systems using discrete mapping models and averaged models. Therefore, we developed a smooth, sigmoid function-based continuous-time model for systems comprising parallel-connected buck converters with average current-sharing control. The proposed model provides a unified description of the continuous and discontinuous conduction modes of the system. The criteria for ensuring the stability of the system were derived based on the Floquet theory. The nonlinear dynamic behavior of the system and the effects of the key parameters on the stability of the system were investigated. The results showed that the system may undergo period doubling bifurcation, border collision bifurcation, and Neimark-Sacker bifurcation as the system parameters varied. The theoretical analysis and simulation results were verified experimentally. Our results provide a basis for the configuration of controller parameters.

S-Domain Model of Single-Sampling and Multisampling DPWM DC–DC Converter Based on Discrete-Time Analysis

<i>s</i>-Domain Model of Single-Sampling and Multisampling DPWM DC–DC Converter Based on Discrete-Time Analysis

Modeling, Control and Simulation of a High-Current DC-DC Converter for Fuel Cell Applications

In this paper, a high-current two-stage DC-DC converter fed by a Proton Exchange Membrane Fuel Cell (PEMFC) is studied. The converter consists of two three-phase full-bridge inverters connected through three AC coupled inductors. The mathematical models of both converter and PEMFC are first presented, and a control scheme that ensures a high power factor at the AC stage and a regulated voltage at the DC load is then implemented. The performance of the proposed control system is verified through digital simulations.

Ripple-Response Modeling and Design-Oriented Analysis of Output Common Power Flow Regulation in Bipolar SIDO DC–DC Converters

Compared with unipolar SIDO DC-DC converters, the output common power flow in the bipolar SIDO DC-DC converters affects lots of system characteristics in high-frequency (HF) region, which poses great challenges for the modeling and design of the bipolar SIDO converters. In this paper, a ripple-response model of the bipolar SIDO DC-DC converter is proposed to capture the HF characteristics by analyzing the response nature and the sampling process of the multi-piecewise current ripple. Based on the derived model, the design-oriented analysis with the change of some key parameters is presented to guide the system optimal design and power flow regulation. Then, the compensators are optimized to improve the dynamical performance and the HF stability simultaneously. Furthermore, the cross-regulation of the SIDO converter is explored via the common- and differential-mode transfer functions. Particularly, the effect of the output common power flow on the cross-regulation is revealed by identifying the frequency-domain coupling point. These analysis results help to suppress the cross-regulation significantly. Finally, the effectiveness of the model and analysis is verified by experimental results. These results show that the proposed method is more suitable for the bipolar SIDO converters to improve power flow regulation in comparison with the existing ones.

State-Space Modeling, Design, and Analysis of the DC-DC Converters for PV Application: A Review

Small-signal models of dc-dc converters are often designed using a state-space averaging approach. This design can help discuss and derive the control-oriented and other frequency-domain attributes, such as input or output impedance parameters. This paper aims to model the dc-dc converters for PV application by employing a capacitor on the input side. The modeling, design, and analysis of the dc-dc converters regarding the input capacitor is limited in the literature. Five dc-dc converters, including buck, boost, buck-boost, ĆUK, and SEPIC converters, are designed and implemented using the state-space average modeling approach in MATLAB/Simulink. The circuit topology of each converter and the state-space matrices are derived considering every constraint. A rigorous and compelling analysis of the dc-dc converters is carried out to compare system stability and, ultimately, the dynamic performance. The output of the resulting small-signal models has been demonstrated in the time-domain against topology simulations. All the converters are exposed to unpredictable weather conditions and the simulations are carried out in the PSIM software. The perturb and observe (P&amp;O) maximum power point tracking (MPPT) algorithm is applied in all the converters to ensure maximum power point (MPP) achievement. The results showcase that the boost converter outperforms all other converters in terms of stability, settling time, and overshoot.

Novel iterative Ragone plot-based optimization of low pass filter for hybrid power sources electric vehicles

The growing demand for eco-friendly transportation has led to the emergence of electric vehicles (EVs). To meet driving requirements and enhance the performance of EVs, researchers combine Energy Storage Systems (ESS) to form Hybrid-ESS (HESS). Efficient power distribution within HESS relies on an effective Energy Management Strategy (EMS). While various EMS methods exist, practical implementation is often hindered by computational complexity. The low-pass filter (LPF) approach is one of the easiest and implementable EMS methods. However, the pivotal challenge lies in determining the optimal cut-off frequency for LPF, a crucial factor influencing energy distribution. Traditional optimization methods, such as Particle Swarm Optimization (PSO) face significant limitations when applied to intricate ESS and DC-DC converter models. Therefore, the iterative method based on the Ragone plot is proposed. Its performance is compared with LPF tuned by PSO. The test results show that the proposed method has a faster process by up to 83.51 % while maintaining comparable performance levels. Compared to battery-only EVs, it is superior in terms of the delta-State of Charge of the battery (delta-SoCB), energy consumption, maximum battery current, and Battery Current Root Means Square (BCRMS). Compared to the Fuzzy Logic Controller (FLC), it outperforms in maximum battery current and BCRMS, with slightly lower delta-SoCB and energy consumption. This highlights the practicality and efficiency of the proposed method, offering a solution for optimizing battery life and power distribution in HESS EVs. Hence advancing the sustainability and performance of eco-friendly transportation systems.

Zero-Backflow Power Control Scheme of Dual Bridge Series Resonant DC–DC Converters With High-Accuracy Time Domain Modeling

In the fundamental harmonic approximation (FHA) modelling of dual bridge series resonant DC-DC converters (DBSRCs), the approximation error of the FHA model will lead to low accuracy of optimization schemes, which will reduce the efficiency of DBSRCs. In this paper, firstly, the time domain analysis (TDA) modelling of the DBSRC is adopted, which can describe the characteristics of the DBSRC accurately. Secondly, the extended phase shift (EPS) modulation based on the TDA modelling is discussed, and the backflow power model with the TDA of the DBSRC is developed. On this basis, a zero-backflow power optimization scheme is proposed. In addition, the effects of dead time are analyzed and the compensation method is proposed. The proposed backflow power optimization method with dead time compensation can achieve zero-backflow power and improve the efficiency of the DBSRC. Especially, the proposed method with TDA modelling is more excellent when DBSRC operates in wide voltage range conditions. Finally, a comprehensive experiment comparison of DBSRC under the minimum current trajectory (MCT) with FHA modelling and the proposed method with TDA modelling is discussed. The experimental results have verified the effectiveness of the proposed scheme.

Analytical and measurement-based wideband two-port modeling of DC-DC converters for electromagnetic transient studies

Analytical and measurement-based wideband two-port modeling of DC-DC converters for electromagnetic transient studies

Modeling and Controller Design of a Hybrid Input-Parallel Output-Serial Modular DC-DC Converter for High Efficiency and Wide Output Range

Modular input-parallel output-serial (IPOS) DC-DC converter is becoming a crucial solution for high-voltage applications due to its flexible combination form without switching device pressure limitation. It requires high efficiency, fast response, and wide-range output for broader applications. However, the existing solutions cannot simultaneously meet all these requirements. This paper proposes a new hybrid structure with interleaved LLC converters and a DAB converter. The interleaved LLC converters provide the most output voltage with fixed switching frequency and duty cycle, while the DAB converter regulates the output voltage. The wide range output is achieved by switching the LLC converter module and continuously adjusting the output voltage of the DAB converter. Furthermore, a switching control method based on the sliding-mode variable structure is proposed to achieve a smooth and fast output voltage response during the switching process. Finally, a 0.3/0.9-1.8kV, 2kW experimental platform is established to verify the proposed converter's effectiveness and advantages.

Dynamic Modelling and Simulation of DC-DC Converters

The DC-DC converter is an electrical circuit that transfers energy from a dc source to an electrical load. [1] The energy is first transferred into the energy storage elements by using the electronic switches, and then afterwards from the storage elements to the load. The storage elements are inductors and capacitors. [2] The transient analysis of the convertersis important to see the dynamic performance of the circuit. The simulations are to be performed to observe the effects of the values of inductor and capacitor on the dynamic performance of the converters. To facilitate the simulation process, the differential equa- tions are formulated into the state-space model of the circuit. The DC-DC converter has the special distinction of being a system of variable structure, that is, the circuit topology changes in accordance with the switching action of the semiconductor devices. The state-space model, therefore, must describe the dynamic behavior of the circuit for each portion of the switching cycle. In this project, the MATLAB software will be used for the state-space model simulation of the converters to see the dynamic performance of the converters in the continuous conduction mode (CCM) and discontinuous conductionmode (DCM).

Model predictive current control for dual-active-bridge dc-dc converter with single-phase shift modulation

This paper proposes a model predictive current control for the dual-active bridge (DAB) dc-dc converter with single-phase shift modulation. The DAB dc-dc converter model is established using the averaging method. To eliminate the steady-state error caused by model uncertainties, the integral of feedback error is combined with the state error to form the augmented system for the control design. Moreover, the controller gain can be systematically tuned by only one tuning scalar variable, making the proposed controller easy to implement. Furthermore, an offline optimization problem is used for computing the controller gain, so real-time computation burden is significantly reduced, enabling the use of low-cost DSP controller. Overshoot-free and fast convergence performance of output current can be achieved using the proposed method in simulations and Typhoon HIL emulator.

Low Frequency Current Ripple Suppression for Two-Stage Single-Phase Inverter Based on Impedance Editing

The instantaneous output power of the two-stage single-phase inverter pulsates at double-line frequency, generating a large amount of second harmonic current (SHC) in the front-end dc-dc converter and input dc source. The SHC is harmful to the system performance. To address the issue, a control strategy based on port-impedance editing, where inductor current feedforward (ICFF) and bus voltage feedforward paths are employed, is proposed to reduce the low frequency ripple in the article. Due to only bandpass filter employed in each feedforward path, the proposed control scheme is relatively easy to be implemented. Under the control strategy, the dc-bus port-impedance of dc-dc converter is increased rapidly at double-line frequency, while staying low impedance for other frequencies. What is more, different ICFF paths are taken into insight to obtain optimized path. Meanwhile, the small signal model of front-end dc-dc converter is established and the design principle of key parameters is provided for the derived control strategy. Furthermore, the dynamic response with bandwidth limitation is also discussed in this article. Finally, a two-stage single-phase inverter prototype was fabricated and tested. The experimental results verify the performance of the proposed strategy with SHC reduction.

Small signal impedance based stability analysis of HVDC aircraft power system

Aircraft energy systems are developed towards multielectricity or fully-electricity. When the original secondary energy sources such as gas and liquid are gradually replaced by electric energy, the types of aircraft electric load will be more diversified, and may bring new impacts on the stability of aircraft electrical system. Therefore, in this paper, the impedance model of three-stage HVDC generator, DCDC converter and constant power load is derived by using small signal impedance modeling method. Simultaneously, the stability of HVDC power system in aircraft is researched by Nyquist stability criterion. The simulation results show that the system is operated stably under 20kW, 30kW and 40kW constant power loads. Finally, a load impedance pre-designed method based on gain and phase margin is proposed in this paper.

Generalized Average Modeling of a Dual Active Bridge DC-DC Converter with Triple-Phase-Shift Modulation

This paper shows an elaboration of an equivalent electrical circuit of a Dual Active Bridge (DAB) and its application as a versatile tool for steady-states analysis in wide range of operating conditions. This work analyses the converter which is controlled with a coherently defined Triple Phase-Shift (TPS) modulation which allows appropriate switching functions to be written, thus enabling the circuit’s state-space equations to be derived. Due to this approach, a Fourier series expansion may be easily applied to utilize Generalized Averaged Modeling (GAM)—a convenient method for modeling resonant and quasi-resonant power converters. Moreover, this paper shows the utilization of the GAM model higher harmonics’ complex magnitudes to calculate the steady-state power characteristics for bidirectional operation; additionally, a method for a particular state variable waveform signal reconstruction is presented. All the discussed model properites are validated with a 1.5 kW 100 kHz SiC-based DAB prototype.

Power converter fault classification method based on multi-feature selection algorithm

In the process of fault diagnosis for the core components of the integrated modular avionics power conversion module, selecting appropriate features can effectively improve the efficiency and classification accuracy of the model, and greatly reduce the computational complexity of the learning algorithm. This paper first designs a typical Sepic structure DC-DC converter model to simulate the typical fault types of the DC-DC converter; secondly, the corresponding original data is obtained through simulation; after data preprocessing, feature extraction and using multiple feature selection fusion algorithm, BP neural network method is used finally for fault diagnosis analysis of DC-DC converter. The simulation verifies the effectiveness of the above method.

Modeling, Analysis, Design, and Simulation of a Bidirectional DC-DC Converter with Integrated Snow Removal Functionality for Solar PV Electric Vehicle Charger Applications

Different factors affect solar photovoltaic (PV) systems by decreasing input energy and reducing the conversion efficiency of the system. One of these factors is the effect of snow cover on PV panels, a subject lacking sufficient academic research. This paper reviews and compares current research for snow removal in solar PV modules. Additionally, this paper presents the design, analysis and modelling of a smart heating system for solar PV Electric Vehicle (EV) charging applications. The system is based on a bidirectional DC-DC converter that redirects the grid/EV-battery power into heating of the solar PV modules, thus removing snow cover, as well as providing the function of MPPT when required to charge the EV battery pack. A control scheme for each mode of operation was designed. Subsequently, a performance evaluation by simulating the system under various conditions is presented validating the usefulness of the proposed converter to be used in solar PV systems under extreme winter conditions.

A Model of DC-DC Converter with Switched-Capacitor Structure for Electric Vehicle Applications

In this paper, a DC-DC converter with an innovative topology for automotive applications is proposed. The goal of the presented power converter is the electrical storage system management of an electric vehicle (EV). The presented converter is specifically compliant with a 400 V battery, which represents the high-voltage primary source of the system. This topology is also able to act as a bidirectional power converter, so that in this case, the output section is an active stage, which is able to provide power as, for example, in the case of a low-voltage battery or a supercapacitor. The proposed topology can behave either in step-down or in step-up mode, presenting in both cases a high gain between the input and output voltage. Simulation results concerning the proposed converter, demonstrating the early feasibility of the system, were obtained in a PowerSIM environment and are described in this paper.