DC-DC Converter Research Articles

Design Interleaved Full Bridge Circuit DC-DC Converter With Fuel Cell Power Source On Hybrid Trains

Design Interleaved Full Bridge Circuit DC-DC Converter With Fuel Cell Power Source On Hybrid Trains

A Method for Improving Radio Frequency Rectification Efficiency in Low-Resistance Loads

Present radio frequency (RF) rectifiers usually suffer from poor power conversion efficiency (PCE) at low-resistance loads, and the currently proposed DC-DC converter cannot solve this problem well. Aiming at this above problem, we propose a novel DC-DC converter for rectifiers, which consists of a Boost–Buck circuit and a Buck circuit cascaded together to maintain high PCE at both high and low load resistance; the converter can also operate over a wide range of input powers. The proposed converter, along with a 2.45 GHz rectifier, was fabricated to verify its performance. With the converter, the load range of the rectifier when the overall PCE is over 50% was extended from 250 Ω–1250 Ω to 5 Ω–3000 Ω. The highest overall PCE reached up to 61% and the overall PCE at a small load of 5 Ω increased from 1.1% to 54%. The proposed converter can be used in wireless power transmission (WPT).

Dynamic Simulation and Optimization of Off-Grid Hybrid Power Systems for Sustainable Rural Development

This paper analyzes dynamic modeling for rural HPS to address GHG emissions’ environmental impact on floods and climate change. The aim is to integrate renewable energy sources, such as solar energy, with traditional generators to mitigate emissions and enhance energy access in rural communities in Pakistan. The system is designed using a DC-DC converter, MPPT, LCL filter, and a DC-AC inverter. Utilizing software tools like PVsyst 7.4 and HOMER Pro-3.18.1, the study evaluates system sizing, energy consumption patterns, and optimization strategies tailored to site-specific data. The expected results include a reliable, environmentally friendly hybrid power system capable of providing consistent electricity to rural areas. The analysis of a connected load of 137.48 kWh/d and a peak load of 33.54 kW demonstrates the system’s promise for reliable electricity with minimal environmental impact. The estimated capital cost of USD 102,310 and energy generation at USD 0.158 per unit underscores economic feasibility. Dynamic modeling and validation using HIL examine the system’s behavior in response to variations in solar irradiance and temperature, offering insights into operational efficiency and reliability. The study concludes that the hybrid power system is scalable for rural energy access, which is a practical solution achieving a 100% renewable energy fraction, significantly contributing to emission reduction and promoting sustainable energy practices.

A non-isolated synchronous buck DC-DC converter, ZVS topology under CCM and DCM conditions

Today, the main challenge of miniaturization and integration of power converters is reducing the volume of parts, eliminating capacitors and inductors.This paper proposes a non-isolated synchronous buck converter (NSBC) under soft switching practice. This converter uses the zero voltage switching (ZVS) topology, which not only provides soft-switching conditions for the converter switches but also prevents the voltage kicking off the two ends of the main switches from being off-state due to self-resonance. To achieve the highest voltage gain in different working cycles, complementary switching approach and use of non-isolated Dc-Dc converter for simultaneous switching of two switches will be used.The non-isolated synchronous buck DC-DC converter with ZVS is to use in some parts of the converter for providing a purpose range of output voltage. In addition, the implementation of the proposed converter control circuit is conducted very simply and needs lower costs. To confirm relations in converter theory, the results of a laboratory sample in the discontinuous and continuous modes are examined. It should be noted that the proposed converter can operate under different levels of voltage, which requires a protection heat policy. The proposed converter implements under the nominal 30-V input and 40 KHz switching frequency, which touches on issues on both sides of discontinuous conduction mode (DCM) and the continuous conduction mode (CCM) conditions and experiment as an example two rates of power 30W and 20W respectively, and also has an acceptable interest rate, which will be evaluated and compared with three different types of similar modes.

Modeling and control of a new multi-port converter for hybrid energy system integration

This research introduces a new topology called the quasi-Z-source integrated isolated multiport bidirectional resonant DC-DC converter. The aim is to achieve cost-effective and efficient multi-directional power flow between photovoltaic (PV), battery/supercapacitor, and DC loads. The proposed topology ensures uninterrupted power supply to the loads and supports reverse power transfer through its bidirectional power flow capability. By combining quasi z-source and H-bridge resonant converters with an existing switch, a four-port converter is achieved without the need for separate converters or additional switches. The high-gain quasi z-source converter reduces the required voltage ratings of the battery and supercapacitor packs while enabling the utilization of a high-frequency transformer (HFT) with a low turns ratio. Isolation between the ports is achieved using a secondary center-tapped HFT equipped with a controlled full-wave rectifier on the secondary side, allowing bidirectional power flow. A power flow management system and corresponding control scheme are proposed to optimize the system's performance. The proposed system's performance is evaluated under various operating conditions, demonstrating its effectiveness in power flow management and overall efficiency. The results confirm the feasibility and effectiveness of the proposed system.

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).

SPICE Modelling-Assisted evaluation of dynamic on-resistance characterization in Schottky p-GaN HEMTs amid synchronous buck transient instabilities

This study addresses the critical gap in dynamic on-resistance characterization for GaN HEMTs within the initial unstable state in a non-isolated DC-DC converter, where the output voltage and currents fluctuate and exhibit overshoots or undershoots before stabilizing to their steady-state values, a domain within solar photovoltaic (PV) Maximum Power Point Tracking (MPPT) implementations which is crucial yet insufficiently examined. The authors present a novel multi-pulse test circuit within a synchronous buck converter configuration, complemented by SPICE simulation. This combination allows for the accurate assessment of clamping circuits' performance during transient states, significantly improving the precision of RDS(ON) measurements in unsteady phases. The approach deviates from conventional methods by merging empirical data with simulation insights to validate the efficacy of clamping circuits. The experimental results affirm the methodology's precision, with the highlighted Circuit V showcasing a marginal deviation of 2.32 % from existing benchmarks. This finding substantiates the method's dependability and practicality contributing to the GaN power electronics field. In addition, this research provides a powerful analytical tool for RDS(ON) evaluation, culminating in the design of a test PCB that synergizes with both simulated and empirical evidence, contributing future research in GaN HEMT power converter applications.

High ratio DC-DC converter based on cascade modified Cuk converter topology

The proposal of a modified Cuk converter as the basic cell in the cascade topology, namely the cascade modified Cuk converter, has been conducted. A scheme for increasing the high voltage ratio using a cascade topology with 3 cells has been obtained, namely by increasing the source voltage to the total output voltage which includes the 3 cells. This will provide a higher voltage ratio than DC-DC converters that do not use cascade topology. In this study, a drop voltage expression due to non-idealities is derived. The voltage losses in the cascade condition will be high if there is an increase in the number of levels. Calculations and simulations on the proposed converter have also been conducted where the optimal duty cycle value is obtained in ideal and non-ideal conditions and the output voltage in both conditions. Experimental results have been given where non-ideal conditions give output voltage results close to the calculation and simulation values so that the duty cycle value becomes a reference in the design of the closed loop control system. Power loss fraction and efficiency have also been given so that efficiency optimization in the cascade modified Cuk circuit can be done to get high efficiency. The proposed closed loop control system has also been given where the control system uses a double-loop control scheme, namely the inner circle for current control and the outer circle for voltage control. Simulations and experiments have been given on the closed loop control system. It is found that the closed loop control system is fast, adaptive, and responsive. The contributions in this paper are to provide the results of simulation and experimental calculations, perform power loss analysis, propose a closed loop control system on the cascade topology, and provide expected results.

PARTICLE SWARM OPTIMIZATION AND CFD ANALYSIS OF A HEAT SINK FOR FORCED CONVECTIVE COOLING OF A DC/AC INVERTER

Power inverters play a crucial role in converting DC voltage and current to AC voltage and current. Its efficient operation relies on effective thermal management of the semiconductor devices, such as the IRF 3205 MOSFET chip which facilitate the switching operations to prevent thermo-mechanical stress that could to failure. This research developed and optimize a heat sink for an IRF 3205 MOSFET chip in a 3.5 KVA power inverter, using the Particle Swarm Optimization technique and experimented with a 3.5 KVA 24 V power inverter operating a 1.5HP air-conditioning unit. The heat sink geometry has 26 fins, 4 mm fin thickness, 40 mm fin height, 3 mm fin spacing, 2 mm fin base thickness, 179 mm length, 80 mm width and a thermal resistance of 60.75 °C/W. The thermal performance was evaluated using ANSYS Computational Fluid Dynamics (CFD) and results showed maximum base temperature of 65.85°C and experimental temperature of 64°C after two hours of steady operation dissipating heat of 45W. The results from both numerical and experimental data demonstrate the effectiveness of the optimized heat sink in maintaining the chip's temperature below its maximum working threshold of 170°C.

Design and investigation of high power quality PV fed DC-DC boost converter

This study presents a new improved voltage gain dc-dc converter architecture to maximize solar photovoltaic (PV) power output. The maximum power point tracking (MPPT) method utilizes particle swarm optimization (PSO)–based artificial neural networks (ANN) to reduce the oscillations of output electrical performance at the maximum power point (MPP). For any solar cell temperature and irradiance, the ANN delivers the electrical current and voltage outputs at the MPP and thus could reach the MPP in minimum instances. A DC-DC converter needs specific characteristics to work with photovoltaic systems. These include higher voltage development to meet increased DC link voltage requirements, the continuous input current to extend the PV system life, common grounding to prevent electromagnetic interference, and reduced electrical stress with fewer components. This paper combines a quasi-switched switch inductor network and extendable diode capacitor modules to achieve the quality mentioned earlier. The converter offers constant input current, high efficiency (95 %) with considerable gain (12 times higher than input), lower voltage stress (almost one-fifth of output voltage), and a common grounding feature. The effectiveness of the proposed MPPT technique is analyzed in terms of higher efficiency, MPP tracking time, gain, and the normalized voltage stress on diodes. The experimental step is developed to validate the simulation (Simulink and Psim) results of the present research work.

Sample Voltage Dead-Beat Control Based on Differentiative Voltage Prediction and Switching-Cycle Extension for DC-DC Converters

In this paper, a sample voltage dead-beat control based on differentiative voltage prediction (DVP) and switching-cycle extension (SCE) is presented to achieve optimal transient response for DC-DC converters under discontinuous conduction mode (DCM) operation. Firstly, to improve load transient response, a DVP method is proposed to estimate the load. With the estimated load, the controller realizes load current feedforward and thus improves the transient response with a wide load range. Secondly, an SCE strategy is proposed to enlarge the output current range and output voltage slew rate, both of which have limited value under conventional digital pulse width modulation (DPWM). When the output current reaches the limited value, the proposed strategy increases the switching cycle to enlarge the current range without losing DCM operation. Finally, combining DVP with SCE, the converter not only achieves optimal response in large signal transients, but also doubles the load range in DCM operation.

A Three-Port DC-DC Converter with Partial Power Regulation for a Photovoltaic Generator Integrated with Energy Storage

A novel integrated DC-DC converter is proposed for the first stage of two-stage grid connected photovoltaic (PV) systems with energy storage systems. The proposed three-port converter (TPC) consists of a buck–boost converter, interposed between the battery storage system and the DC-AC inverter, in series with PV modules. The buck–boost converter in the proposed TPC is utilized for maximum power point tracking by regulating two power switches. The output power of the proposed converter is regulated by controlling the DC-AC converter. During the battery-charging mode, partial power regulation is employed with a direct power flow path (the series-connection of the PV panel, the battery and the output). As resistances in this path are almost negligible, the power conversion efficiency is higher than existing topologies. During battery-discharging mode, the power conversion is processed through a buck–boost converter with only two active power switches and one inductor. With fewer components, higher power conversion efficiency is also achieved. The circuit operation and analysis are presented in detail. To illustrate the simplicity of the converter control, the performance of the converter is tested with a straightforward maximum power point tracking on a PV system with battery cells. Simulation and experimental tests are carried out to demonstrate circuit operation and power conversion efficiency.

Harmonic modelling and control of dual active bridge converter for DC microgrid applications

Due to the intermittent power availability from renewable sources, the bidirectional DC-DC converter (BDC) must integrate with the energy storage system for bidirectional power flow. Among many BDCs, the Dual Active Bridge (DAB) converter is the most promising because of the system's power handling capacity and efficiency. DAB bidirectional DC-DC converter is a topology with the advantages of a decreased number of devices, soft-switching commutations, low cost, and high efficiency. This work describes the guidelines for designing a DAB converter for small DC microgrid applications. It is shown that the judicial selection of reactive elements leads to soft switching for all the switches in the converter in varying load conditions. A guideline for the controller design is given and the operations are validated through the simulation. A harmonic modelling technique has been implemented to model the DAB converter based on an efficient closed-loop regulator. A solar PV system has also been implemented here with a SEPIC converter that is used as an interfacing element between the PV system and the load bus. At last, a DC Microgrid is simulated in a PSIM environment to showcase its various modes of operation. It is shown that the battery bank can support variable loads independently through the DAB converter. In inadequate solar power generation, load power demand is shared between the battery and PV system. In case of deep discharge of the battery, the PV system can charge the battery through a DAB converter.

An integrated switched capacitor coupled inductor Buck-Boost DC-DC converter

An integrated switched capacitor coupled inductor Buck-Boost DC-DC converter

DESIGN OF MULTI-PORT DC-DC CONVERTER

Integrating Energy sources to have a sustainable energy supply is an important aspect to handle the significant loads. Multiport power converters are used to connect various types of energy sources and loads. The key advantages of multi-input converters lie in their capability to interface with multiple input sources such as solar panels, wind turbines, batteries, and grid power, thereby optimizing energy utilization and enhancing system reliability. In the paper, a new configuration of single switch Dual– Input Single-Output (DISO) DC-DC converter is proposed. This paper presents an overview of multi-input converters, focusing on their design, operation, and applications in renewable energy integration Multiport converter reduces the system size and cost by reducing the number of components. The proposed converter is verified in MATLAB/ Simulink and validated with simulation results. Key Words: Dul-input single-output converter (DISO), switch, and Multiport converter.

Dynamic output feedback based fault tolerant control for continuous-time switched affine systems via reduced-order observer

In this study, the issue on dynamic output feedback fault-tolerant controller design is addressed for a class of continuous-time switched affine systems in the presence of actuator faults. The existence of affine terms gives rise to the lack of a common equilibrium point and further makes it more difficult to propose the desired output-feedback-based fault-tolerant control scheme. Firstly, the actuator fault estimation is achieved through a reduced-order observer design approach. Then, a kind of dynamic output feedback controller is constructed to perform the fault tolerance goal by utilizing fault estimation information. Moreover, the mode-dependent average dwell time switching constraint is borrowed to avoid the chattering owing to the high-frequency switching. The sufficient conditions with less conservative are derived to guarantee the practical exponential stability of closed-loop system with a prescribed L∞ gain. Finally, both the effectiveness and validity of the designed fault-tolerant control strategy are illustrated via a case study of a buck-boost DC-DC converter.

Optimised linear active disturbance rejection control of multiport-isolated DC-DC converter for hydrogen energy storage system integration

Hydrogen energy storage systems are becoming increasingly accepted owing to their environmental friendliness. The efficiency and performance of these systems largely depend on the attributes of their power electronic interface systems. Among the promising solutions is a multiport-isolated DC-DC converter with characteristics of reduced component count, fewer conversion stages, and galvanic isolation. However, this system presents a challenge due to its inherent cross-coupling effect, complicating precise control. To address this, linear active disturbance rejection control (LADRC) is a viable option, leveraging dynamic/disturbance properties observed by linear extended state observers. LADRC serves as a decoupling controller, mitigating the cross-coupling effect. However, LADRC has several gains, and selecting them can be a difficult task, often requiring manual tuning. To streamline this process, this paper proposes utilising particle swarm optimisation to determine the optimum gains of LADRC. By employing this approach, the implementation of LADRC is facilitated with reduced design efforts while ensuring effective decoupling control within the system. Simulations are conducted to validate the performance of the optimised gain LADRC.

Design of digital compensators for multi-output DC-DC converters with reduced cross-regulation

ABSTRACT In the recent times, a single multi-port DC-DC converter (MPC) is highly preferred over the multiple single output DC-DC converters. Single Input Dual Output (SIDO) Buck converter with Coupled Inductors (CI) are widely employed for the reduction of multiple outputs. In this paper, the prognostic procedures to monitor MPC operating with load dynamics are discussed. The occurrence of cross-regulation during the load dynamics is suppressed by an improved digital compensator, which was specifically designed to address the cross-regulation problem. The developed digital compensation circuit is employed in the CI-SIDO Buck converter with an input of 48 V and delivering outputs of 12 V/75Watts and 24 V/125 Watts. The occurrence of cross-regulation is controlled by decoupled dual loop digital PID controller with dynamical digital compensation. A meticulous Frequency Response Analysis (FRA) with bode plot is conducted exhaustively for the derived system transfer functions. The proposed design is verified in simulation and experiments, exhibiting an enhanced results with significant suppression in cross-regulation and stability.

Low-power DC-DC converters for smart and environmentally-friendly electric vehicles: design, simulation, and fabrication on a glass substrate

This research focuses on evaluating and comparing different DC-DC converter designs, specifically for low power applications. The study considers inductor-based, switching capacitor, and linear voltage regulator (LVR) DC-DC converters. While there has been critical investigation of DC-DC converters in the literature, there is a gap in assessing their performance based on a comprehensive set of conflicting parameters. Additionally, there is a lack of research on matching the most suitable DC-DC converter with specific low power applications. The chosen application for this study is a DC-DC converter on a glass substrate, specifically for smart glass in electric vehicles. The research presents a complete process that includes design, simulation, layout, fabrication, and measurement. Through simulations, a 4.8 V to 3.3 V buck converter is recommended, demonstrating an almost ideal response time and minimal output ripples. Experimental measurements also confirm a low output ripple of 0.3 %. By addressing this research gap and providing a comprehensive evaluation of DC-DC converters, this study contributes to the development of efficient and reliable power solutions for smart glass applications in electric vehicles.

Analysis of the effect of mutual inductance on reducing output current ripple of the modified DC-DC Cuk converter

DC-DC converters exhibiting minimal input and output ripple are extensively employed across a diverse range of applications. This paper presents a proposed modification to the DC-DC Cuk converter. The converter is developed by modifying a conventional Cuk DC-DC converter to exhibit boost characteristics. The DC-DC converters possess the capability to function as versatile units that can be employed in a multitude of applications, ranging from DC-DC conversion to DC-AC conversion (inversion). This paper presents a novel DC-DC converter design that aims to achieve reduced ripple in both input and output currents. By employing the principle of mutual inductance, it is possible to further mitigate the presence of ripple current. The analysis of the impact of mutual inductance on the output voltage and ripple current of the proposed converter has been conducted. The validity of the derived analytical method has been confirmed through both simulated and experimental investigations. The utilization of mutual inductance in the proposed modified Cuk converter has been demonstrated to result in reduced current ripple.