Performance Of DC-DC Converter Research Articles

Improved dynamic performance of triple active bridge DC-DC converter using differential flatness control for more electric aircraft applications

The triple active bridge (TAB) converter has been proposed to improve power density and availability in more electric aircraft applications. However, the conventional proportional-integral (PI) controller used for TAB voltage control often exhibits slow response and significant overshoot, which can impact dynamic performance. Moreover, achieving decoupling control among ports introduces computational complexity in controller design. To address these issues, this paper introduces an effective diagonal matrix decoupling strategy based on differential flatness control with single-phase shift modulation applied to a TAB converter. The proposed differential flatness control offers superior transient performance, control flexibility, and precision, ensuring compliance with DC voltage regulations while achieving optimal decoupling among ports. The comparative analysis assesses various criteria, including steady-state and dynamic performance, control complexity, and regulation and tracking properties, against PI control, unit matrix decoupling control, and the proposed differential flatness control. Hardware-in-loop (HIL) experimentation verifies the performance, confirming faster dynamic characteristics and robust port power decoupling. The results show a significant improvement in efficiency, reaching a maximum of 95.5 %, indicating reduced switching losses and enhanced overall system performance. The study concludes with a discussion on the implications of these findings and potential future research directions, such as integrating advanced optimization algorithms further to enhance the control strategy's robustness and adaptability.

Advanced Multi-Sampling PWM Technique for Single-Inductor MIMO DC-DC Converter in Electric Vehicles

Amongst the various topologies of multi-input multi-output (MIMO) DC-DC converters, single-inductor MIMO (SI-MIMO) converters have the advantages of a reduced component count, a simpler structure, and low cost. These converters are suitable in electric vehicle (EV) applications involving variable ports, essential for performing different functions. Digital control in SI-MIMO converters is promising for enhancing transient performance due to its numerous benefits. However, delays in digital control, particularly computational and pulse width modulation (PWM) delays, can negatively impact the performance of DC-DC converters. Multi-sampling and double PWM update methods can mitigate these control delays, but they often necessitate complex control schemes, adding computational burden. In this work, an advanced multi-sampling PWM technique, integrating sample shift and multi-sampling, is proposed while employing a simple digital PID control scheme. The proposed method was tested for a shared-switch SI-MIMO converter with battery discharging and charging modes in the MATLAB/Simulink environment and compared with the conventional single- and multi-sampling PWM methods. The results demonstrated that the proposed method significantly improved the converter performance, surpassing the conventional single- and multi-sampling PWM methods. In the battery discharging mode, utilizing the proposed method, the output voltage achieved a settling time of 0.075 s in response to a step change in its reference, significantly outperforming multi-sampling, which yielded a settling time of 0.124 s, and single sampling, which exhibited an even longer settling time of 0.898 s. It also demonstrated a minimal overshoot of 0.06 volts compared to 1.5 volts with multi-sampling during the step change in the input voltage. Similarly, in the battery charging mode, upon a step change in the reference output voltage, the proposed method effectively minimized the overshoot of the output voltage to 0.845 volts compared to 1.175 volts with multi-sampling, and it decreased the inductor current settling time to 0.296 s from 0.330 s recorded under multi-sampling. These findings underscore the potential of the proposed method in enhancing the digital control performance of SI-MIMO DC-DC converters in electric vehicles.

A 2.5–8V input range peak-current-control non-inverting buck-boost DC-DC converter with high efficiency and automatic mode transition for Ni-MH battery application

In portable electronic devices, the output voltage of the Ni-MH cell battery gradually decreases with the extension of run time, eventually leading to an inability to provide the required operating voltage. As a result, this paper proposed a non-inverting buck-boost converter with automatic switching of operating modes to extend the run time of Ni-MH batteries connected in series, which is peak current controlled. By comparing the input and output voltages, the DC-DC converter is placed in either buck, boost, or buck-boost mode. Of the three modes, the buck-boost mode is designed to have the smallest operating range due to its lowest power conversion efficiency. The converter is characterised by a wide input range of 2.5–8 V, which exceeds the maximum voltage leading to oxide breakdown. In order to prevent the breakdown of the gate oxide layer, a capacitive coupling level shift circuit is proposed to control voltage between gate and source of the power transistor below 5 V. The proposed converter is manufactured using a 180 nm BCD process and occupies an effective chip area of 1.44 mm × 0.73 mm. Experimental results demonstrate that the maximum power conversion efficiency of the proposed buck-boost DC-DC converter is 93%, marking a significant 11% enhancement compared to the traditional buck-boost DC-DC converter operating in only buck-boost mode (84% efficient). In addition, the converter achieves a maximum output current of 500 mA, which improves the output maximum current by 67% compared to the traditional DC-DC converter (max. output current 300 mA).

Analysis of Scalable Resonant DC–DC Converter Using GaN Switches for xEV Charging Stations

In this research, an innovative electric vehicle (EV) charger is designed and presented for xEV charging stations. The key feature of our system is a scalable, interleaved inductor–inductor–capacitor (iL2C) DC-DC converter operation. The proposed system employs two parallel L2C converters with 8-GaN switches on the primary side and a shared rectifier circuit on the secondary side. This configuration not only amplifies the resonant tank internal currents and losses generated by the switches but also improves current sharing. A novel closed-loop technique is proposed with a constant-voltage method of operation, along with a hybrid control scheme of variable frequency + phase shift modulation (VFPSM). To examine the controller and converter’s performance, an experimental demonstration is conducted under varying load conditions, including full load, half load, and light load, where the source voltage and load voltage are maintained at constant levels of 400 Vin and 48 V0, respectively. Furthermore, line regulation is conducted and verified to accommodate a broad input voltage range of 300 Vin–500 Vin and 500 Vin–300 Vin while maintaining an output voltage of 48 V0 at 3.3 kW, 1.65 kW, and 0.33 kW with a peak efficiency of 98.2%.

A single switch high gain multilevel boost converter with switched inductor topology for photovoltaic applications

This paper proposes a new transformer-less single-switch high-gain dc-dc converter for solar power systems. The suggested converter is created by supplementing the conventional boost converter with a switched inductor cell plus a voltage multiplier stage. The converter has several benefits, including a high voltage conversion ratio, reduced voltage stress on semiconducting switches and diodes, a reduction in the need for gate drivers because only one switch is used, as well as constant input current to prolong the lifespan of the photovoltaic cell. The analytical waveforms of the recommended converter can be seen in the continuous conduction mode (CCM). The analysis of voltage stress is done. In the presence of parasitic components, increased voltage gain and efficiency were also obtained.The proposed high-gain converter topology is compared to recently published high-gain converter topologies in terms of performance. Using PSIM, a high-gain dc-dc converter's performance is studied and analysed with regard to its low switching voltage stress. The suggested converter is successful in stepping up 20V to 400V at 160W power capacity, while offering a continuous input source current at 95% efficiency.

A Comparative study on the operation and output waveforms of an SG3524 DC-DC Converter

A Comparative study on the operation and output waveforms of an SG3524 DC-DC Converter

Design and development of modified high efficient high gain DC-DC converter for SPV standalone systems

<p class="MDPI17abstract"><span lang="EN-US">A conventional DC-DC converter is not viable for power conditioning in standalone solar photovoltaic applications. Switching losses are the primary reason for the poor performance of conventional DC-DC converters. To mitigate the issues in conventional DC-DC converters, a high efficient high gain (HEHG) DC-DC converter is designed and developed in this research work. Modified HEHG converter utilizes the passive components switched capacitors, coupled inductor, and resistor capacitor (RC) snubber circuit for minimizing the switching losses and improving the overall power conversion efficiency of the solar photovoltaic (SPV) system. In addition, a modified <br /> D-sweep maximum power point tracking (MPPT) algorithm is in-corporate into this system to improve the tracking efficiency of the SPV system. HEHG for a standalone system is designed using MATLAB/Simulink environment and developed the hard-ware prototype. As a part of the validation, real-time testing is carried out and compares the performance of the HEHG converter with a traditional DC-DC converter. The theoretical efficiency of the HEHG converter is 96.01%, and the real-time efficiency is 95.62%. Found that theoretical and practical values of performance parameters are closely tallying.</span></p>

Dead-Time Effect and Compensation Technology for an Isolated Dual Active Bridge Converter

Aiming at deficiencies of output voltage distortion and circulating current generation caused by dead-time effect in the modulation process, a simple and feasible dead time compensation strategy is presented. Firstly, the influence of dead-time effect on the output voltage of bridge is analysed, and a dead time compensation strategy is added between the modulation signal and dead time procession. According to the current direction of the bridge, the rising edge or falling edge of the driving signal is selectively delayed to compensate for dead-time effect. Secondly, an Optimized Triple Phase-shift (OTPS) modulation strategy is adopted with minimizing leakage inductor current Root-Mean-Square (RMS) control, which minimizes current stress, achieves soft-switching operation, avoids phase-shift errors caused by Dead-Time Effect, and optimizes control performance of DC-DC converters. Finally, simulated and experimental results are added to verify the correctness and effectiveness of the proposed method.

Stable Equilibrium Rotor Positions for Three-Phase Switched Reluctance Machine

In mobile applications such as eletric vehicles, weight and installation space are the primary limiting factors that affect the system efficiency and consequently the driving range. Reusing the machine windings of an electrical machine as inductors, e. g. in DC-DC converters for onboard chargers, saves weight and space. However, currents in the machine windings when operating as DC-DC converter can result in undesired torque ripple generated by the machine. Therefore, stable rotor positions of a switched reluctance machine have to be found to prevent it from rotating in DC-DC converter operation mode. In this study, stable rotor positions for a wide range of current distributions are determined, enabling flexibility in the choice of currents. A method to analyze such stable equilibrium positions for switched reluctance motors is presented. The proposed method is used to determine the stable positions that facilitate flexible current distribution between phases. Moreover, locus curves are calculated, simulated, and measured to illustrate and evaluate stable rotor positions for the various current distributions.

A Novel Standalone Implementation of MDNN Controller for DC–DC Converter Resilient to Sensor Attacks—A Design Approach

Power electronic converters have become an integral part of the direct current microgrid (DCMG) systems. The efficient control of these converters will decide the performance of the DC microgrids. With the evolution of cyber physical systems, all these power converters are integrated into the communication networks to achieve intelligent and smart control. Data in the communication networks are highly vulnerable towards cyber-attacks, leaving it unaddressed will lead to substantial economic losses and disasters. This article proposes a standalone implementation of multi-deep neural network (MDNN) based DC-DC converter and its application to detect false data injection (FDI) attacks at the sensor level. A MDNN is developed with a combination of deep neural network (DNN) and error detection network (EDN). DNN is used as the controller to achieve closed loop operation of DC-DC converter and EDN is used to detect and mitigate the FDI attack. Initially, proposed scheme is executed in MATLAB simulink platform with various disturbances at controller level and several attack scenarios are verified with its experimental results.

PV System with Battery Storage Using Bidirectional DC-DC Converter

With the increase in demand for generating power using renewable energy sources, energy storage and interfacing the energy storage device with the load has become a major challenge. Energy storage using batteries is most suitable for renewable energy sources such as solar, wind etc. A bi-directional DC-DC converter provides the required bidirectional power flow for battery charging and discharging mode. The duty cycle of the converter controls charging and discharging based on the state of charge of the battery and direction of the current. In this paper, a nonisolated bi-directional DC-DC converter is designed and simulated for energy storage in the battery and interfacing it with the DC grid. The power extracted from the solar panel during the daytime is used to charge the batteries through the DC-DC converter operating in buck mode and when solar power is unavailable, the battery discharges to supply power to DC load through the converter operating in boost mode. Solar arrays connected through a DC bus to a load. Due to the instantaneous changes of solar irradiance and temperature, maximum power point tracking (MPPT) is integrated in the inverter control. The technique of maximum power point tracking (MPPT) is used in photovoltaic systems to extract the maximum power. The most popular MPPT techniques are reviewed and studied, such as: Perturb and Observe, Increment of Conductance and control based on fuzzy logic (LF). The simulation is done in matlab/simulink and results are presented.

Analysis of the high-gain BOCUK DC-DC converter-based PFC using an LQR controller for SMPS applications

This research work emphasizes on the development of a unique high-gain BOCUK DC-DC converter for Switched Mode Power Supply (SMPS) applications. The high-gain BOOST-CUK (BOCUK) DC-DC converter combines the benefits of both Boost and Cuk converters for attaining instantaneous line current shaping and load regulation. The proposed BOCUK converter provides a non-inverted output and improves the voltage gain and efficiency. The modes of operation of the high-gain BOCUK DC-DC Converter in a Continuous Conduction Mode (CCM) with parasitic elements in the circuit are examined and a state-space model is constructed. The second-order model is derived using the Modified Hankel Matrix Method (HMM) to make the controller design easier. Dual-loop Control employing an inner Linear Quadratic Regulator (LQR) current Controller and an outer Atom Search Optimization (ASO)-tuned Proportional Integral (PI) controller is used to analyze the performance indices of the high-gain converter and fluctuations in line, load and setpoint are investigated. Simulation results prove that the LQR controller is robust in tracking the load voltage and provides excellent line current shaping with low % Total Harmonic Distortion (THD) and nearly Unity Power Factor (UPF). The hardware model for 200W is built and implemented using the TMS320F28027F microcontroller to verify the simulation results.

A Load Adaptive Hybrid DPS Control for DAB to Secure Minimum Current Stress and Full ZVS Operation Over Wide Load and Voltage Conversion Ratio

Wide variations in voltage conversion ratio and loading are the most important parameters to consider when designing off-board EV chargers to achieve high power density and efficiency. Dual phase shift (DPS) modulation provides a better way for dual active bridge (DAB) DC-DC converter operation when load side parameter variation is utmost important. To accomplish this, conventional DPS control is modified to ensure zero voltage switching (ZVS) across the entire load range despite wide variations in voltage conversion ratio. The designed control provides ZVS of all FETs as compared to the conventional DPS control over full loading range. For this, magnetizing inductance of HF isolation transformer is utilized and designed to shape the secondary side current for getting ZVS for both active legs. The light loading performance of the converter is improved with the bidirectional conduction angle control. The hybrid utilization of DPS control is incorporated with minimum peak current stress considerations. A Karush-Kuhn-Tucker (KKT) method based on Lagrange's multipliers is used for mathematical derivation of optimized solution of both control parameters. Performance of designed control is verified using experimental results for wide variation in battery terminal voltage. For validation, a 1250 W laboratory prototype is developed. A comparison of ZVS regions among the conventional and designed modulation technique, shows the effectiveness under wide voltage and loading scenarios.

DESIGN AND ANALYSIS OF BIDIRECTIONAL BUCK-BOOST CONVERTER FOR GRID TO PHEVAND PHEV TO HOME

Nowadays, the use of Electric Vehicles (EV) is rapidly increasing. The batteries of the EV are charged when its demand is low, and the energy would then be stored to act as a kind of reserve that could be used when necessary. A new design of “bidirectional DC-DC buck boost converter” is suggested for transferring electrical power between the grid and an electric vehicle, as well as between an electric vehicle and the residence. While using grid energy to charge the car battery, the Grid to Vehicle (G2V) mode utilizes a buck mode DC-DC converter operation. The Vehicle to Home (V2H) function uses the battery's stored energy to power dwellings off the grid when the DC-DC converter is running in boost mode. The battery's Status of Charge is determined using an enhanced Kalman filter. Proportional-integral controllers are used in bidirectional buck boost converters to maintain a consistent voltage on both the high voltage and low voltage sides. Phase angle control is used for G2V and V2H operations on the H-Bridge inverter that the DC-DC converter is coupled with. The proposed circuit is simulated in MATLAB, and the results are reviewed.

A Current-Source Converter with a Hybrid Dc-dc Converter Interfacing an Electric Vehicle and a Renewable Energy Source

The increasing demand for electricity and the impact of the consumption of fossil fuels leads to the need for approaching new alternatives of energy production, namely energy storage systems (ESS) and renewable energy sources (RES). For this purpose, this paper presents a single-phase current-source converter (CSC) with a hybrid dc-dc converter connected to the dc-link, which not only allows the interface of an electric vehicle (EV) and a RES, but also operates as shunt active power filter (SAPF). The operation as SAPF is performed through the CSC connected to the power grid, compensating some power quality problems that can occur in the electrical installation, namely current harmonics and low power factor. Moreover, the CSC can operate as a grid-tied inverter or as an active rectifier. Regarding the hybrid dc-dc converter, the main role of this power converter is to interface the CSC dc-link with the power converters for the EV and RES interfaces. As demonstrated along the paper, the CSC, combined with the hybrid dc-dc converter, allows the operation as SAPF, as well as the operation in bidirectional mode, specifically for the EV operation, and for injecting power from the RES. In this paper, the power electronics structure is described in detail, and the operating principle is introduced, supported by the description of the control algorithms. The validation results show the proper operation of the CSC as SAPF and the operation of the hybrid dc-dc converter as EV battery charger and discharger, as well as RES interface.

Recent Advances in DC-DC Converters for Electric Vehicles

The emergence of electric vehicles (EVs) has become a better alternative to withstand enormous damage to the environment and human life due to the widespread use of conventional cars. As a vital element in EVs, this paper analysed and compared the key features of different DC-DC topologies from different areas, then, explored strategies to improve DC-DC converter performance. The purpose of all these studies and designs is to help researchers in the automotive industry to choose the right DC-DC converter topology for their needs to achieve the required power density. By continuously improving the design and evaluation of DC-DC converters, it can improve the performance and efficiency of electric vehicles, and further promote the use of sustainable energy. This will help reduce reliance on traditional fuels, lower carbon emissions, improve air quality and move the entire transportation industry towards a greener, more sustainable future.

Exact Feedback Linearization of a Multi-Variable Controller for a Bi-Directional DC-DC Converter as Interface of an Energy Storage System

DC microgrids have shown to be a good approach for better accommodating stochastic renewable energy sources (RES) and for the charging of electric vehicles (EVs) at the distribution level. For this, fast-acting energy storage units (ESSs) are essential. This requires that both the bi-directional power converter topology and the control scheme present the right set of features. The ESS discussed in this paper consists of a new DC-DC converter based on a tapped inductor (TI) for a higher voltage gain at moderate duty cycles. The direction of the current in its intermediate inductor does not need to be reversed for power flow reversal, leading to a faster action. Moreover, it can employ a multi-state and multi-variable modulation scheme that eliminates the right half-plane (RHP) zero, common in boost-type converters. In order to achieve good dynamic performance across a wide range of operating points, a control scheme based on feedback linearization is developed. This paper presents the modeling of the five-switch DC-DC converter operating in the tri-state buck–boost mode. A systematic approach for deriving control laws for the TI current and output voltage based on exact state feedback linearization is discussed. The performance of the proposed control scheme is verified by simulation for a supercapacitor (SC)-based ESS. It is compared to that of a conventional control scheme for a dual-state buck–boost mode with cascaded PI controllers designed based on small-signal models. The results show that both control schemes work similarly well at the operating point that the conventional control scheme was designed for. However, only the proposed scheme allows the SC-based ESS to control the current injected into the DC microgrid with the voltage of the SC varying between the expected range of rated to half-rated.

Comparative Study of DC-DC Converters for Solar PV with Microgrid Applications

This review emphasizes the role and performance of versatile DC-DC converters in AC/DC and Hybrid microgrid applications, especially when solar (photo voltaic) PV is the major source. Here, the various converter topologies are compared with regard to voltage gain, component count, voltage stress, and soft switching. This study suggests the suitability of the converter based on the source type. The merits of a coupled inductor and interleaved converters in micro gird applications are elucidated. The efficiency and operating frequencies of converts for different operating modes are presented to determine the suitable converters for inductive and resistive loads. The drawbacks of converters are discussed. Finally, the mode of operation of different converts with different grid power sources and its stability and reliability issues are highlighted. In addition, the significance of the converter’s size and cost-effectiveness when choosing various PV source applications are discussed.

Bidirectional Isolated Hexamode DC–DC Converter

The proposed isolated buck-boost series resonant dc dc converter contains two full-bridge hybrid switching cells capable of half-bridge operation. This feature is regarded as topology morphing control. The voltage buck regulation requires special modulations applied to the primary-side hybrid switching cell. In contrast, the voltage boost regulation requires special modulations for the secondary-side hybrid switching cell. Combining the topology morphing control with the buck-boost regulation capability a novel dc-dc converter operating in six different modes is derived. Moreover, the proposed converter is capable of bidirectional operation. This paper describes how the topology morphing control influences the converter dc voltage gain, which results in three boost and three buck modes. The obtained six modes are described and equations for the converter dc voltage gain are provided. Selected design guidelines for the power part and control system are presented. Using those, a 350 W prototype was designed and built. Experimental results confirm the theoretical expressions for the converter dc voltage gain. Experimental efficiency is provided in a wide input voltage range for both energy transfer directions. Analysis of operating points with the highest thermal stress of components is presented with corresponding power loss breakdown calculations confirming measured thermal results.

Performance evaluation of a PMDC motor with battery storage control and MPPT based solar photovoltaic system

This paper analyzes and demonstrates the performance of a solar photovoltaic (SPV)-fed permanent magnet DC (PMDC) motor under various operating conditions. In this configuration, a 5HP PMDC is coupled to a SPV system and a boost converter has been interfaced between them to regulate the DC output voltage acquired from the SPV system. The switching pulse to the converter has been provided by the maximum power point tracking (MPPT) controller (P&O and INC) in order to acquire maximum and desired power across the DC link with varying irradiance. A battery energy storage system (BESS) is often used in association with this configuration caused by the non-linear nature of the SPV system and to overcome the volatility of the DC connection affected by environmental effects. For this purpose, a double loop PI controller is analyzed, and examined the DC link. Additionally, the operation of bidirectional DC-DC converter in buck and boost mode during battery charging and discharging is also performed. This operation ensures maintaining a constant and continuous power across the DC link to regulate the PMDC motor consistently. A comparison of results has also been presented for both incremental and conductance (INC) and P&O controllers. The mathematical modeling of configuration has been performed in MATLAB/Simulink software. The results and key findings have been tabulated and even elaborated graphically.