Low Voltage Stress Research Articles

Ultra‐high gain quadratic boost DC–DC converter based on a three‐winding coupled inductor with reduced voltage stress for fuel cell‐based systems

AbstractHere, an ultra‐high gain quadratic boost DC–DC converter (UQBC) based on the conventional quadratic boost converter (CQBC) and a three‐winding coupled inductor (TWCI) has been proposed. It benefits from an extensive voltage gain range and low voltage stress on semiconductors. In addition, the converter requires a reasonable number of components. This structure is suitable for connecting renewable DC power sources like fuel cells to a DC‐bus in DC microgrids. Unlike CQBC, the produced conversion ratio has been improved to [1+n+m+d(1+n)]/(1−d)2 thanks to integrating a TWCI into CQBC. As a result, the proposed quadratic boost converter gives a better step‐up factor than previously presented quadratic boost converters (QBC). Meanwhile, the employed improvement method has not adversely affected some critical parameters like voltage stress on semiconductors or the input current ripple. This paper presents the mathematical analysis and operating principle of the proposed topology for both continuous and discontinuous current modes (CCM and DCM). Experimental results are represented to validate the converter theory and its performance. Results indicate that a high gain and efficiency have been obtained. Also, the voltage stress on the power switch is reduced by one‐fourth by choosing a proper duty cycle and winding coefficient.

Performance of a novel DC-DC low voltage stress boost converter for fuel-cell vehicle

Air pollution, global warming, depletion of fossil fuels and the lack of access to them due to potential political conflicts are some of the challenges that have forced governments to take necessary measures to promote and invest in the development of electric vehicles (EVs). One of the most important parts of EVs is dc-dc converter. A novel step-up single-switch unidirectional topology for a dc-dc converter is proposed in this paper. Some of the advantages of the proposed topology are the use of single-switch, ground switching, low input current ripple, wide range of voltage gain (VG), high level of VG, low stress level for semiconductor components, low input current ripple, small number of semiconductor and passive elements, high efficiency, and no need for high frequency transformer or coupled inductors. Topology analysis is done in continuous current mode (CCM) and calculations related to efficiency and appropriate design are performed to select the converter parameter values. Also, the proposed topology is compared with other similar topologies to show its high performance and superiority. To confirm the theoretical basis, laboratory prototype waveforms are evaluated and an efficiency of 93.2% is obtained.

Ultra high voltage gain non-isolated DC-DC converter based on new interleaved triple boosting technique

This paper introduces a DC-DC converter that employs a modified triple boosting architecture (MTB), interleaved with modified switched inductor capacitors (MSIC), to achieve ultra-high voltage gain in photovoltaic applications. The converter design also includes a modified switched inductor with a modified voltage multiplier mode (MVM), which interleaves with the main switch and effectively doubles the voltage transfer gain. Furthermore, a modified triple boosting mode technique, utilizing interleaved components and an auxiliary switch, is integrated into the converter design. The main switch and auxiliary switch, combined with modified voltage multiplyer, contribute to achieving high voltage gain. The proposed converter offers numerous advantages. It exhibits remarkable efficiency while ensuring low voltage stress across diodes and MOSFETs. Moreover, by utilizing low inductance and capacitance values at high switching frequencies, the converter’s overall performance is enhanced. To validate and substantiate the simulation and laboratory results, the converter has undergone PCB design and experimental testing. Specifically, this converter is designed to boost input voltage levels ranging from 30 V to 40 V to a variable output voltage between 200 V and 400 V, with a power output of 360 W and an efficiency rating of 96.5%.

Implementation of non-isolated high-gain DC-DC converter for electric vehicle application

ABSTRACT This paper introduces a non-isolated high voltage gain DC-DC converter for electric vehicles (EVs). The proposed converter schematic is modelled to be operated on reasonable duty cycle by employing passive switched inductor (PSL) cell and voltage multipliers. Moreover, this structure is functioning on continuous conduction mode (CCM) with a wide range of operations. This structure offers high voltage gain, lower voltage stress across all the devices, low switching losses and high efficiency. Thus, simple proportional integral (PI) controller is adopted to regulate the output to the desired voltage of 200 V. The proposed converter is designed and simulated using MATLAB/Simulink platform and hardware prototype of 100 W/200 V is developed to examine the performance of the proposed circuit. Besides, the experimental results are recorded to prove its robustness over both source voltage and load power discrepancies. The efficiency of the presented configuration is around 91% and it acts as a good choice for EV applications.

A Flat-Top Single-Ended Resonant Converter With Low Switch Voltage Stress

This paper proposes a flat-top single-ended resonant converter (SERC) for wireless charger with the merit of low switch voltage stress, by introducing a parallel LC network in series with the primary switch. A characteristics analysis of the proposed SERC is performed in time domain, obtaining the ZVS condition, power transfer capacity expression and the time requirement to achieve an ideal voltage cancelling. Due to the injected third harmonic, the voltage waveform of the switch can be shaped into a near trapezoid or a saddle shape. From the perspective of waveform superposition, we derive the conditions for the minimum switch voltage stress and the flat-top waveform of switch voltage. Finally, a 1900W prototype is built to verify the theoretical analysis. The experimental results show that the proposed converter achieved a flat-top switch voltage waveform and the voltage stress of 2.12 times the input voltage at full load, compared to that of 2.65 times the input voltage for the conventional one. Besides, the maximum efficiency is also increased to 93.33% from 92.32%.

A Family of Impedance Source DC-DC Converters With Zero Input Current Ripple

A family of impedance source DC-DC converters with zero input current ripple is proposed in this paper. The proposed converters include one additional input inductor, a capacitor and a winding coupling with the Y-source on the input side of the original impedance source converters. The voltage of the added winding is opposite of that of the input inductor. Accordingly, the input current ripple can be reduced to zero. Moreover, the two input inductors can be coupled, it means only one capacitor and two windings are needed to be added in the proposed converter. Above all, the proposed converters can promote the life of the photovoltaic array due to the reduction of the input current ripple. In addition, the proposed converters inherit all advantages of the original converters, like high voltage gain and low voltage stress. Detailed theoretical analyses and experimental tests verify the validity of the proposed converters.

A New Triswitching Double Duty High Voltage Gain Boost Converter for DC Nanogrid Application

The Tri-switching Double Duty Converter (TSDDC) is a new non-isolated high gain DC-DC boost converter topology presented in this paper for 400V PV-based DC Nanogrid application. In a conventional DC nanogrid system, two DC-DC converter has been used, one for stepping up the voltage & the other for maximum power point tracking mechanism (MPPT). The proposed TSDCC can perform both operations in a single stage. The proposed converter has been controlled by two duty ratios ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\delta _{1}$</tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\delta _{2}$</tex-math></inline-formula> ) with the help of three switches. The highlighting feature of TSDDC are i) Controlled on two different duty cycles ii) High voltage gain at low duty ratio iii) Lower voltage stress on switches and diodes. The TSDDC is simulated for 500W power with 400V. The working of the converter is explained in detail for continuous conduction mode (CCM). In addition, design guideline and comparative study are also presented. Furthermore, a control scheme is implemented that controls MPPT(maximum power point tracking). A lab prototype of TSSDC was developed for 21V-400V, 400W and the switching frequency is 50kHZ. The proposed TSDDC converter's operating concept and controllability are verified by the simulation results.

Dual-Stacked Bidirectional Boost/Buck DC–DC Converter

A new non-isolated bidirectional DC-DC converter with low voltage and current stresses across the semiconductor devices is presented in this paper. The proposed converter is a combination of a dual-stacked bidirectional boost converter. The converter presents different operations modes, such as: synchronous and asynchronous. These modes can reduce the current ripple of the voltage source. Besides that, in this paper, the modeling and control of the proposed converter are done. To validate the theoretical evaluations of the proposed converter, a 1 kW, 144 V/ 400 V prototype was built to verify its performance where the peak efficiency is 96.33 % and 96.87 % for step-up and step-down modes, respectively.

An ultrahigh synchronous drive step-up converter for PEMFC and its explicit model predictive control: A neural network fitting strategy

This paper proposes an ultrahigh synchronous drive step-up dc-dc converter to improve the low voltage generated by proton exchange membrane fuel cell (PEMFC) with proper duty cycle. Coupled inductor and voltage multiplier technologies are utilized to obtain high voltage gain in the converter. The energy stored in leakage inductor can be recycled by the clamp circuit, reducing the voltage stresses on switches, and improving the efficiency significantly. The operating principles and steady-state analyses in continuous conduction mode are provided in detail. Compared with relevant converters, the proposed converter performs lower voltage stresses on power switches and higher voltage gain. Moreover, to improve the dynamic performance and interference immunity of the proposed converter, the offline fitting strategy using the explicit model predictive control (MPC) laws of neural networks is used. The tracking accuracy of the output voltage is improved, disturbances caused by variable loads are reduced, and superior dynamic response can be achieved. Finally, to verify the feasibility and validate the theoretical analyses, a 200 W laboratory prototype with input voltage 20 V and output voltage 400 V is implemented. The maximum efficiency of the proposed converter is 97.21% and the full load efficiency is 91.67%.

Power controlled by Two Type Direct Power Control Quality Improvement of PV Grid-tied based on Two Parallel Inverters

Due to the growing demand for photovoltaic power generation systems for grid-connected renewable energy systems, the high-quality energy and the good efficiency are necessary. For this reason, two-level parallel inverters are used in grid-connected PV systems connected to standard AC and DC connections are widely utilized. This structure is often relied on to raise the quality of the power and increase the power conversion efficiency. This article proposes a grid-tied energetic system composed of a photovoltaic source connected to the grid by the means of DC-DC boost converter controlled by hell clamping algorithm MPPT to improve the harvesting of the PV power, and of two VSIs connected in parallel interfaced by a coupling filter and controlled by two methods namely, classic DPC-PI and improved DPC-ST. An extensive simulation analysis was carried out to validate the proposed control approach by the comparison with the conventional method base on PI regulator. The proposed technique introduced a superior performance in terms of lower voltage stress at the DC-link, the THD of the injected current, and the ripples of the active and reactive power.

Implementation of a novel buck‐boost converter based on coupled inductor for renewable energy applications

SummaryA coupled inductor based on dual switches buck‐boost converter is proposed in the article, which can be used in renewable energy applications. A wide conversion ratio can be realized by regulating turns ratio of the coupled inductor and the duty cycle. The topology has a quadratic‐like voltage gain, and the low voltage stress and current stress. Combing the passive clamping circuit to recover leakage energy, the voltage spikes of power switches are suppressed, improving the efficiency. Moreover, it has the merits of continuous input current and common ground. To demonstrate the superior performances of the presented converter, the principle of operation and steady‐state analysis are presented in detail. At last, a 100‐W experimental prototype was designed to verify the correctness of the theoretical analysis, with a maximum efficiency of 95.7% in step‐up mode and 96.8% in step‐down mode.

A Non-Isolated High Voltage Gain DC–DC Converter Suitable for Sustainable Energy Systems

A non-isolated high gain DC–DC converter with magnetic coupling and a VM circuit is proposed in this study. By the use of the appropriate coupled inductor turn ratio, the output voltage of the recommended topology can be raised. The VM circuit is used to boost the voltage gain even further as well as to clamp the voltage spike across the switch, which results in a lower voltage on the switch. As a result, a MOSFET switch with a lower ON-state resistance (RDS-ON) is used which, in turn, causes the conduction losses to be reduced and the entire system efficiency to be raised. Another advantage of the proposed structure is the ZCS of the diodes, which reduces the voltage drop losses caused by the regenerative diodes. The function modes analysis and the theoretical equations are accomplished. A comparison survey with other prior works is being developed to investigate the competency of the proposed converter. Based on this, the higher voltage gain and efficiency as well as the lower voltage stress on the semiconductors can be achieved by the proposed converter compared to the other converters. The effectiveness of the proposed converter is confirmed by the experimental results at a laboratory-scale operating under 150 V output voltage with a 96% efficiency at the 150 W full load and a 25 kHz switching frequency.

A Novel Three-Winding Coupled Inductor-Based High Step-Up DC-DC Converter for Renewable Energy Application

This paper presents a novel nonisolated high step-up dc-dc converter for renewable energy generation system. The converter combines a three-winding coupled inductor, voltage multiplier cells, and two power switches with simultaneous operation. Compared with existing high step-up converters, the proposed converter can achieve high voltage gain under a low number of turns ratio while avoiding a large duty cycle. Moreover, the passive clamp circuit recycles leakage inductor energy and reduces the voltage spike of switches. Continuity of input current and existence of a common ground between the input energy source and load make the converter suitable for renewable energy applications. Also, the proposed converter shares high voltage gain with low voltage stress on semiconductors (switches/diodes), improved compactness and high efficiency. The operating principles and steady-state analysis of the proposed converter are illustrated. Then the theoretical efficiency analysis, and performance comparison with other converters are discussed. Finally, a 200 W prototype with 380 V output voltage is established based on the design guidelines, and experimental results verify the accuracy of the theoretical analysis.

An X-Type Boost Multilevel Inverter Based on Switched Capacitor Cells With Low-Voltage Stress and High-Frequency Applications

An X-Type Boost Multilevel Inverter Based on Switched Capacitor Cells With Low-Voltage Stress and High-Frequency Applications

Nonisolated High-Step-Down DC–DC Converters With Low Component Count and Voltage Stress

This paper proposes two new non-isolated high step-down DC/DC converters. The converters' voltage conversion ratio and their semiconductor components' voltage stress are improved compared to the conventional buck converter. By coupling the inductors of the first proposed converter, its volume and price is reduced. By employing a clamp circuit with low elements to the first proposed converter, the second proposed converter is introduced, in which its voltage conversion ratio and the voltage stress of components are improved significantly; thus, in high input voltage applications, high-quality components (switches with low on-resistance and diodes with low forward voltage) can be used. In these converters, the leakage inductances of the coupled inductor are clamping, and their energy is recovered. The proposed converters have fewer elements than related high step-down counterparts' converters leading to lower volume and losses due to lower elements, increasing efficiency. The switches of the proposed converters are switches simultaneously, reducing the converters' control circuit complexity. This paper discusses the theoretical analysis and operational principle of both proposed converters. Besides, to verify their performances, experimental results of the converters with 155-24 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> input and output voltage are presented.

Circulating Current Suppression Scheme for Interleaved Active Neutral Point Clamped Nine-Level Inverter

The interleaved active neutral point clamped nine-level (ANPC-9L) inverter can be used in 1500V photovoltaic power generation because of its advantages of low voltage stress, high equivalent switching frequency and small filter size. Circulating current between sub modules is a key problem for ANPC-9L. A simple scheme to realize circulating current suppression for ANPC-9L inverter is presented in this paper. The operation of the ANPC-9L is briefly discussed, and the model of coupled inductor is given. Analysis shows that the redundant working states of the inverter with same output voltage can be used to suppress the circulating current. Another objective is to analyze circulating current imbalance at the band transition when using phase disposition pulse width modulation (PD SPWM) strategy. A solution is proposed to cancel current imbalance. Simulation and experiment verify the effectiveness of the proposed strategy.

A voltage lift‐based high‐gain DC‐DC converter with low input current ripple

AbstractThe switched‐inductor‐based voltage lift converters offer high voltage gain. However, their input current has step changes due to switched‐inductor configuration and is peaky due to the voltage lift capacitor charging current. This article proposes a new high‐gain DC‐DC converter where an additional boost converter cell is incorporated in a conventional voltage lift boost converter to charge the voltage lift capacitor with a constant current, avoiding a peaky charging current from the supply. The operating principle of the proposed converter demands phase‐shifted switching signals to achieve high voltage gain and reduce ripple in the input current. High‐gain, continuous input current, positive output voltage, common ground between input and output ports, and low voltage stress on active switches are the major characteristics of the proposed converter. The operating principle, steady‐state analysis, and control design have been discussed in detail. A 200 W, 30 V/300 V, and 50 kHz laboratory prototype is developed to validate the operation of the proposed converter.

A New Single-Cell Hybrid Inductor-Capacitor DC-DC Converter for Ultra-High Voltage Gain in Renewable Energy Applications

In this paper, a new single-cell hybrid switched inductor DC-DC converter is proposed to demonstrate the verification of ultra-high voltage gain in renewable energy applications (REA). The modification involves adding a single cell of an inductor with a diode and double capacitor to increase voltage transfer gain. Additionally, this modification helps prevent the input current from becoming zero, pulsating at very low duty cycles. The single cell of the hybrid inductor is interleaved with the main switch to reduce current stress when the capacitor of the single-cell inductor charge becomes zero. Moreover, the addition of a modified hybrid switch inductor with a capacitor, operating in dual boosting mode with a single switch, allows the converter to achieve ultra-high voltage gain. The proposed converter offers several advantages, including ultra-high voltage gain, high efficiency, low voltage stress on power MOSFETs, diodes, inductors, and capacitors, as well as low switching and conduction losses. Furthermore, the proposed converter utilizes transformerless and non-coupled inductors. Mathematical equations have been derived for the discontinuous conduction mode (DCM) and continuous conduction mode (CCM) and implemented using Matlab Simulink software to validate the results. In addition, a dual PI controller is designed for the proposed converter to verify the fixed output voltage. Experimental results have also been obtained for a 200 W prototype, with the input voltage varying between 20 V and 40 V, and an output voltage of 200 V at an efficiency of 96.5%.

An Improved Asymmetric Modulation of Current-Source Rectifier With CM Filter for Low Voltage Stress on Switching Devices

Common mode (CM) filters are usually utilized in high power density three-phase current source rectifier (3ph-CSR) to suppress the CM noise in the input currents. However, when CM filters are utilized, the inductor currents at the positive and the negative ends of the DC side of 3ph-CSR are unequal, which brings high voltage stress on switching devices. To reduce the voltage stress on the switching devices, an improved asymmetric modulation is proposed in this letter. In the proposed asymmetric modulation, two switching devices are always turned on in each sector, which clamps the voltage of the switching devices to the peak of the input line voltages. A 1kW experimental prototype of the 3ph-CSR is built to verify the analysis results.

A Family of Symmetrical Bipolar Output Converters Based on Voltage-Multiplying Rectifiers for Interfacing Renewable Energy With Bipolar DC Microgrid

The bipolar dc microgrid system is considered a greatly promising solution to interface various renewable energy sources and emerging loads due to its advantages in efficiency and reliability. However, pole voltage imbalance and lack of superior bipolar power conversion topologies limit the development and application of bipolar DC microgrid systems. In this context, this paper proposes a family of multi-port converters based on voltage-multiplying rectifiers to achieve symmetrical bipolar output voltage and power conversion between renewable energy sources and bipolar buses. In the proposed topologies, single-stage power conversion, without voltage balance feedback control, and a low number of components are obtained. Furthermore, the bulky balancing inductor is eliminated to improve conversion efficiency and reduce the volume of the system. Moreover, the higher voltage gain, smaller input current ripple, and lower voltage stress of semiconductor devices make it ideal for interfacing renewable energy sources with bipolar DC microgrids. The derivation method for the proposed topology family is first introduced. Then, a typical topology in the proposed converter family is analyzed in detail as an example, including the operation principle, steady-state performance, parasitic parameter effects, design considerations, efficiency analysis, control method, loop designing, etc. Finally, a 1-kW prototype is developed and tested to verify the performance of the proposed converter.