DC-DC Converter Research Articles

Non-isolated high step-up DC-DC converters based on geometric structure model

Non-isolated high step-up DC-DC converters based on geometric structure model

Design and analysis of a switch fault-tolerant multi-input single-output DC-DC converter for high reliability applications

The DC–DC converters have been used extensively in various industrial applications such as consumer electronics, aerospace, electric vehicles, and renewable energy systems. The reliability ensures that the converter continues to operate safely and efficiently despite the presence of faults. Enhancing the reliability of DC-DC converters is a challenging task, as power switches are the most fragile components that can be affected by faults in the system. Hence, to address these challenges and ensure the safety of the converter, it is vital to implement appropriate fast fault-diagnosis techniques and fault-tolerant strategies. Many new network topologies have been presented in literature, which lead to a shift from single input–single output to multiport converters. These converters are suitable for integrating different energy sources. However, the majority of them are operated using a time-sharing method, in which only one energy source is used at a time, and the others are inactive at any specified duty cycle. Therefore, the converter and input sources are underutilized in the conventional time-sharing approach. This paper proposes a new multi-input single-output (MISO) converter topology with fully integrated switch fault tolerance. It can perform multi-input buck, boost, and buck-boost operations. More importantly, the converter can operate uninterruptedly for single or multiple switch faults. Using simulation and experimental results, a 400 W prototype circuit is designed to analyze the converter's reliability and performance.

A 380 V High Efficiency and High Power Density Switched-Capacitor Power Converter using Wide Band Gap Semiconductors

State-of-the-art switched-capacitor DC-DC power converters mainly focus on low voltage and/or high power applications. However, at high voltage and low power levels, new designs are anticipated to emerge and a power converter that has both high efficiency and high power density is highly desirable. This paper presents such a high voltage low power switched-capacitor DC-DC converter with an input voltage up to 380 V (compatible with rectified European mains) and an output power experimentally validated up to 21.3 W. The wide band gap semiconductor devices of GaN switches and SiC diodes are combined to compose the proposed power stage. Their switching and loss characteristics are analyzed with transient waveforms and thermal images. Different isolated driving circuits are compared and a compact isolated half bridge driving circuit is proposed. The full-load efficiencies of 98.3% and 97.6% are achieved for the power stage and the complete power converter, without heatsink or airflow. The corresponding power densities are 7.9 W/cm3 and 2.7 W/cm3, based on boxed volumes, respectively.

A Novel Multi-loop Fuzzy Logic Dynamic Controller for Wind/Photovoltaic-Grid Interface DC Energy Utilization Farm

This paper proposes a novel control system for control of a hybrid wind/photovoltaic (PV) farm utilization with alternative power source for DC type loads. A controller consisting of six different loop controllers is mainly used to regulate the DC-DC converter to reduce a weighted total sum of all loop errors, to mainly track a given speed reference trajectory depicting the demand for discharge or flow and also to ensure power quality, reliability and stability. The proposed control function is digitally simulated using the MATLAB/Simulink/ SimPower System software environment. The dynamic performance of the hybrid system is examined for the control system validation under normal and abnormal operating conditions.

Sensitivity analysis of a High Gain DC/DC boost converter including parasitic parameters

A high gain DC/DC boost converter is presented. This circuit is analysed with reference to the sensitivity analysis of the static gain transfer function including parasitic parameters. Results demonstrate that a low parasitic resistance of the input inductor gives a quasi-ideal behaviour in terms of efficiency and boosting but, on the other hand, it implies high variation of the static gain versus the duty cycle at its high. This kind of analysis is particular meaningful, since it has been demonstrated that the sensitivity of the HG (High Gain) boost DC-DC converter to the parasitic resistance of the input inductance is higher for lower values of the parasitic resistance.

Dynamic Control of Fuel Cell Powered Water Pumping Station

An efficient renewable green energy system consisting a hydrogen PEM-fuel cell as an energy sources is simulated and studied in this paper. The proposed green scheme has four separate key components. The first is the green power generation source. The second is the interfacing DC-DC converter used to connect green power generator fuel cell to the load bus. The third is a common DC interface-bus where the generated energy is collected in a DC form. The fourth comprises all interfacing error driven controllers and novel modulated green plug power filter (GPPF) used to reduce ripple variations and stabilize the common DC-Bus voltage. In this paper, the novel multi-loop error driven dynamic controller scheme is implemented for speed control of the PMDC motor. This multi-loop controller comprises three basic loops, the main supplementary dynamic momentum loop to ensure fast dynamic and minimum current and torque ripple content. The proposed fuel cell generation scheme provides efficient and optimum dynamic operation to enhance system performance and secure energy supply. The proposed integrated hybrid system with all subsystems has been simulated using the Matlab Simulink/Sim-Power software environment and validated for voltage stabilization, efficient utilizations and enhanced power quality under different operating conditions, sudden load excursions, despite the non-linear volt-ampere characteristic of the fuel cell DC generator source.

A High-Efficiency DC-DC Converter Based on Series/Parallel Switched Inductor Capacitors for Ultra-High Voltage Gains

A high-efficiency DC-DC converter employing a modified architecture called the hybrid switched inductor–capacitor series (MHSLCS) is proposed in this paper. The primary goal is to achieve a notably ultra-high voltage gain for renewable energy systems (RESs). Furthermore, the use of only one input capacitor in the MHSLCS eliminates pulsations in the input current at both low and high duty ratios. The proposed converter integrates the MHSLCS with a modified switched capacitor (MSC) that interleaves with the main MOSFET, effectively doubling the voltage transfer gain. Additionally, a modified hybrid switched inductor–capacitor parallel (MHSLCP) is incorporated in parallel with an interleaved auxiliary MOSFET. Both MOSFETs, combined with the MSC, contribute to achieving an ultra-high voltage gain. In addition, the inductors of the MHSLCP operate in a discontinuous conduction mode (DCM), which results in significant stress reductions in the power diodes and switches at high output voltages. The advantages of the proposed converter are multifaceted, demonstrating a high efficiency while minimizing the voltage in power device diodes and MOSFETs. The use of low inductance and capacitance values at high switching frequencies further enhances the performance. Wide-bandgap (WBG) power devices are employed to achieve the desired high voltage gain and efficiency. The proposed converter was designed with a PCB and underwent experimental testing to validate laboratory results. The proposed converter boosted the input voltage from 30 V to a variable output voltage between 325 V and 500 V, with a power output of 325 watts and an efficiency of 95.5%.

Designing a High-Order Sliding Mode Controller for Photovoltaic- and Battery Energy Storage System-Based DC Microgrids with ANN-MPPT

This paper introduces a robust proportional integral derivative higher-order sliding mode controller (PID-HOSMC) based on a double power reaching law (DPRL) to enhance large-signal stability in DC microgrids. The microgrid integrates a solar photovoltaic (SPV) system, an energy storage system (ESS), and DC loads. Efficient DC-DC converters, including bidirectional and boost converters, are employed to maintain a constant voltage level despite the lower SPV output power. An artificial neural network (ANN) generates the optimal reference voltage for the SPV system. The dynamical model, which incorporates external disturbances, is initially developed and based on this model, and the PID-HOSMC is designed to control output power by generating switching gate pulses. Afterwards, Lyapunov stability theory is used to demonstrate the model’s closed-loop stability, and theoretical analysis indicates that the controller can converge tracking errors to zero within a finite time frame. Finally, a comparative numerical simulation result is presented, demonstrating that the proposed controller exhibits a 58% improvement in settling time and an 82% improvement in overshoot compared to the existing controller. Experimental validation using processor-in-the-loop (PIL) confirms the proposed controller’s performance on a real-time platform.

Development of high-gain switched-capacitor based bi-directional converter for electric vehicle applications

High efficiency, high voltage transfer ratio (VTR), and low input ripple current is required in any bidirectional DC-DC converter (BDC) that plays a major role in interfacing batteries in applications like dc microgrids and electric vehicles (EVs). For meeting these requirements, a switched capacitor-based BDC is proposed to interface the battery with a propulsion system via DC Link. It has a simple circuit with only a set of switching operations, High VTR, and lesser ripple current on the low voltage (LV) side are advantages of the proposed High Gain Switched-Capacitor Bi-directional DC-DC Converter (SC-BDC) making it appropriate for use in EVs. The steady-state analysis, design consideration of passive components, loss and efficiency analysis are presented. Finally, the proposed High Gain SC-BDC is compared with few of the existing BDC in the literature. The feasibility of the converter was demonstrated by simulating a 200 W converter and validating results produced in a MATLAB environment.

A Wide-Output-Range DC-DC Converter and Minimum Loss Collaborative Control Strategy

In response to the challenges faced by traditional LLC resonant converters in simultaneously achieving a wide output voltage and high efficiency, this paper proposes a cascaded DC-DC converter. The front stage of the converter adopts a new LLC topology, and it is cascaded with a boost converter through a reutilization of the output-side inductor. The proposed DC-DC converter leverages the electrical isolation and wide output voltage range advantages of LLC and boost converters, enabling the overall system to achieve broad output voltage regulation and high-efficiency operation. The reutilization of the inductor design further enhances the integration density of the DC-DC converter. A minimum loss collaborative control strategy is introduced for the proposed DC-DC converter. When determining the output voltage and operating the circuit in step-up mode, the duty cycles of the switch in the proposed LLC converter and the switch in the boost converter are adjusted to minimize overall circuit losses while ensuring the rated output voltage. Ultimately, the correctness and practicality of the proposed DC-DC converter and its control strategy are validated through a simulation and an experiment. The overall efficiency of the DC-DC converter can reach up to 94% under optimal conditions.

Analytical and experimental studies on improved performance high frequency multiphase synchronous DC-DC converter using SiC MOSFETs and coupled inductors

Analytical and experimental studies on improved performance high frequency multiphase synchronous DC-DC converter using SiC MOSFETs and coupled inductors

Effect of Oxidant Concentration on Properties of Ferrite Films by Spin-Spray Deposition

In response to the demands for high frequency, miniaturization, and high integration in electronic devices, such as inductors and DC-DC convertors, nickel–zinc ferrite thin films exhibit significant application value and development potential. For regulating the magnetic properties and microstructure of spin-sprayed polycrystalline ferrite materials, a comprehensive understanding of the impact of oxidant concentration on film reaction is essential. This study finds that as the concentration of the NaNO2 oxidant increases, the grain size of the nickel–zinc ferrite thin film samples progressively enlarges. Due to the preferential occupation of iron ions at the B sites, the saturation magnetization correspondingly increases. However, when the oxidant concentration becomes excessive, the preferential (222) orientation growth of the film is disrupted, leading to the agglomeration and uneven growth of grains, transitioning from triangular plate-like to spherical in shape. This increase in grain size alters the magnetization mechanism of the thin film, predominantly favoring domain wall movement. Upon analyzing the microstructure and magnetic characteristics, it becomes evident that the concentration of oxidant is a key determinant in the spin-spray deposition process.

Modeling and simulation of photovoltaic powered battery-supercapacitor hybrid energy storage system for electric vehicles

Energy storage is crucial for the powertrain of electric vehicles (EVs). Battery is a key energy storage device for EVs. However, higher cost and limited lifespan of batteries are their significant drawbacks. Therefore, to overcome these drawbacks and to meet the energy demands effectively, batteries and supercapacitors (SCs) are simultaneously employed in EVs. A solar photovoltaic (PV) powered battery-supercapacitor (SC) hybrid energy storage system has been proposed for the electric vehicles and its modeling and numerical simulation has been carried out in MATLAB Simulink. The SC is used to supply the peak power demand and to withstand strong charging or discharging current peaks. It also improved the battery pack's durability and extended its life. Different topologies of battery and SC have been explored and their capacity to manage the battery stress is assessed. The passive topology is found to be the most suitable for the proposed model due to its ease of implementation and absence of control scheme. A hybrid topology is used to share the power across batteries, supercapacitors and the PV system. In the proposed hybrid energy storage system, a sudden load on the battery is shifted towards the capacitor and thus, the battery heating is reduced, that ultimately improved the vehicle performance and reduced the charging time. In addition, the supercapacitor stored a lot of energy in a short period of time and delivered more power to the load without experiencing any life-span deterioration. The results indicated that employing a passive DC-DC converter and hybrid energy storage system (HESS) reduced the battery power by 52 %, while the passive HESS system reduced the motor current by 94 %. The supercapacitor also recovered 51 % more energy while starting and can offer peak power more efficiently than a battery.

SEPIC-Boost-Based Unidirectional PFC Rectifier with Wide Output Voltage Range

A novel unidirectional hybrid PFC rectifier topology based on SEPIC and boost converters is proposed, which is applicable to various industrial applications such as electric vehicle charging stations, variable speed AC drives, and energy storage systems. Compared to other rectifiers, the proposed SEPIC-boost-based rectifier exhibits continuous current on the AC side, lower voltage stress on the active switches, a wider range of DC output voltage, no auxiliary DC-DC converters, and a high step-up static voltage gain operating with low input voltage and a low step-up static gain for the high-input-voltage operation. These traits allow the SEPIC-boost-based rectifier to utilize smaller input-side harmonic filtering inductors and adopt active switches with lower voltage ratings, resulting in reduced conduction losses. Additionally, the proposed rectifier features power factor correction and high boost/buck voltage-gain capabilities, simplifying control for electric vehicle charging and expanding its range of applications. In this paper, the operating principle of the novel topology is presented first, and then the mathematical model of the proposed rectifier is built. Based on this, the comparison between the proposed topology and conventional boost and SEPIC converters is given. Furthermore, the control strategy, including the high-power-factor control and the balancing control to the DC capacitor voltages, is discussed. Finally, to validate the accuracy of the proposed rectifier’s theoretical research, a 500-W SEPIC-boost rectifier system has been constructed in the laboratory, generating a 200/120 Vdc output voltage from a 155 Vpk/50 Hz power source.

Patent Research of DC Electric Drive Power Supply Systems Based on Active Converters With Power Correction

Despite the fact that the AC electric drive has recently been increasingly “displacing” the DC drive, it is quite relevant, because completely satisfies the requirements of technological processes. Consideration of the problem of electromagnetic compatibility of DC converter installations with the supply electrical network occupies a large place. The article provides research and analysis of the influence of valve loads on the quality of the power supply network and ways to improve the quality of power supply by replacing existing converters with active DC-DC converters with power factor correction, as well as a patent study.

Calibration of Ring Oscillator-Based Integrated Temperature Sensors for Power Management Systems.

This paper details the development and validation of a temperature sensing methodology using an un-trimmed oscillator-based integrated sensor implemented in the 0.18-μm SOI XFAB process, with a focus on thermal monitoring in system-on-chip (SoC) based DC-DC converters. Our study identifies a quadratic relationship between the oscillator output frequency and temperature, which forms the basis of our proposed calibration mechanism. This mechanism aims at mitigating process variation effects, enabling accurate temperature-to-frequency mapping. Our research proposes and characterizes several trimming-free calibration techniques, covering a spectrum from zero to thirty-one frequency-temperature measurement points. Notably, the Corrected One-Point calibration method, requiring only a single ambient temperature measurement, emerges as a practical solution that removes the need for a temperature chamber. This method, after adjustment, successfully reduces the maximum error to within ±2.95 °C. Additionally, the Two-Point calibration method demonstrates improved precision with a maximum positive error of +1.56 °C at -15 °C and a maximum negative error of -3.13 °C at +10 °C (R2 value of 0.9958). The Three-Point calibration method performed similarly, yielding an R2 value of 0.9956. The findings of this study indicate that competitive results in temperature sensor calibration can be achieved without circuit trimming, offering a viable alternative or a complementary approach to traditional trimming techniques.

Hybrid MGWO- CSO optimized high gain Relift Luo converter for PV based grid tied PMBLDC drive system

Permanent Magnet Brushless Direct Current (PMBLDC) motor has become one of the most important motors in high performance drive systems, for industrial uses especially for electric vehicle (EV) applications to minimize their torque and current ripples. This work proposes a PV based high gain DC-DC converter for uninterruptible constant power supply to the PMBLDC drive application. PMBLDC drive with Hall Effect sensorsis used to make the variable speed operation due to its controllability. In this work, a Relift Luo converter is utilized because of its negligible ripple in output DC voltage, high voltage gain and reduced switching losses. To regulate this converter, PI controller is implemented and to tune the parameters of the controller, Hybrid Crow Search -Modified Grey Wolf Optimization (MGWO-CSO) techniqueis implemented. The surplus energy from PV is transferred to grid through Single phase Voltage Source Inverter (1 φVSI) after generatingadequate power to PMBLDC motor. When there is no power in Photovoltaic (PV)cell during night time, stored energy in grid gives supply to the PMBLDC motor. The motor is effectively controlled by the PI controller along with the hysteresis controller. Furthermore, the developed work is executed in MATLAB/Simulink to foreshow its effectiveness. As a consequence, the proposed work accomplished low THD value of 1.34, high efficiency of 98.2% with reduced switching lossescompared to the conventional techniques.

An electro-optic (EO) pulsed electric field sensor powered by photovoltaic cell

Considering the limitations of battery-powered active EO modulated electric field sensors, a photovoltaic cell-powered electric field sensor is designed, fabricated and experimentally demonstrated. The sensor is consisting of a laser photovoltaic cell-powered supply circuit, a receiving modulation circuit, and an induction antenna. The laser photovoltaic cell power supply circuit which composed of a power supply laser, a photovoltaic cell, and a DC-DC conversion circuit is designed and fabricated. Experimental results show that the photovoltaic cell power supply circuit can output stable voltages of 5 V and 1.2 V for the receiving modulation circuit. A lightning impulse (LEMP) measurement system is set up and used to test the characteristics of the electric field sensor in the time domain. The experimental results show that the sensor detected pulsed electric field shows good consistency with the applied LEMP in the time domain and the dynamic range of the sensor is from 0.86 kV m−1 to 10.7 kV m−1.

A New Double-Switch SEPIC-Buck Topology for Renewable Energy Applications

In addition to their conventional use in electric motor drives, DC-DC converters have a variety of other uses, such as energy storage, energy conversion, cyber security systems, uninterruptible power supplies, and renewable energy systems. An innovative DC-DC converter is suggested in this article. Designing a new, high-gain DC-DC converter scheme known as a double-switch SEPIC-buck converter (DSSB) is possible after making some adjustments to the SEPIC converter that is currently known in accordance with accepted techniques. The output voltage magnitude of the proposed converter is either larger than or less than the input voltage magnitude and is the same sign as the input voltage. According to the theoretical and analytical study that has been supported by the real-world application, high voltage gain, low switching stress, and low inductor current ripple are the main characteristics of the proposed DSSB converter. The related small-signal model was also used to build the closed-loop system. The frequency response and output voltage behavior were investigated when the input source voltage abruptly changed as a step function. Based on the comparison study with other DC-DC converters, the DSSB converter outperforms currently known DC-DC converters such as Buck, SEPIC, Boost, Buck-Boost, and other SEPIC converter topologies in terms of voltage gain, harmonic content, normalized current ripple, dynamic performance, and efficiency. Additionally, the frequency response and control of the proposed converter using an alternate current (AC), small-signal, analysis-based, current-mode control technique are both provided. Thus, the DSSB is regarded as safe in overcurrent situations because of the small-signal analysis with the current control strategy. As a result of the verification of the proposed control technique, the resistance to changes in the DSSB parameters, improved dynamic performance, and higher control accuracy are further advantages of current-mode control based on small-signal analysis over other control approaches (PI controllers). Finally, the experimental and simulation results from Simplorer 7 and MATLAB/Simulink are used to validate the findings of the analytical and comparative investigation.

A novel ZVS full-bridge cascaded step-up DC-DC converter with resonant auxiliary circuit for high voltage-gain applications.

High conversion ratio dc-dc converters have received significant attention in renewable energy systems, primarily due to their necessary high-gain characteristics. This research proposes a high step-up ratio full-bridge resonant cascaded (FBRC) dc-dc converter designed for use in photovoltaics (PV), fuel cells (FC), electric vehicles (EV), and other low-voltage output energy sectors to achieve high voltage gain. This converter contains a full-bridge cell with a boost input inductor, a diode-capacitor cascaded stage that replaces the transformer as a voltage multiplier and an inductor-capacitor (LC) parallel-series resonant network across the FB terminal. One of the strategic features of the converter is its high voltage step-up characteristic combined with lower duty cycle operation that limits the maximum current through the active devices, making it particularly suitable for systems that generate low output voltage. In addition, zero-voltage switching (ZVS) is achieved during the turn-off and turn-on operation of the FB switches from 25% to full load, thereby lessening the switching losses. Moreover, the diminished necessity for passive components and the decreased voltage stress on both active and passive devices lead to the use of smaller and more cost-effective components. The theoretical analysis of the proposed converter is validated using a 500 W laboratory-scale prototype wherein high-performance SiC-based MOSFETs have been utilized as switching devices. It offers reduced ripples, with input current ripple at 5% and output voltage ripple at 0.76%. When the load is 400 W and 60 V as the input voltage, the maximum efficiency is found 95.8% at 400 V output voltage. The proposed dc-dc converter, with its high voltage gain and reduced component stress, shows significant promise for application in renewable energy systems.