Voltage Gain Ratio Research Articles

A Stacked Symmetrical Non-Isolated High Step-Up Voltage Gain Converter with High Efficiency and Low Voltage Stress on Components

This paper introduces a cascaded symmetrical non-isolated high step-up voltage gain converter with high efficiency and low voltage stress on components combining a non-isolated buck-boost converter and voltage doubler structure. In the proposed converter, the input source is connected in series to the output load; hence, a part of the source energy is directly delivered from source to load, not through the switching branch, improving efficiency. Furthermore, the appropriately stacked voltage doubler stage not only amplifies the high step-up voltage gain ratio but also considerably diminishes the voltage stress on all semiconductor devices and capacitors. As a result, the costless low internal resistance and low voltage components can be employed for higher efficiency, higher power density, and lower cost. To demonstrate the practicality of the proposed topology, the operating principle is outlined, and the steady-state characteristics are thoroughly analyzed. Furthermore, a 360 W prototype converter has been fabricated to confirm the efficiency of the proposed converter.

Comparative Analysis of SS, SP, PP and PS Topologies for Magnetic Coupled Wireless Power Transfer System Composed of the Negative Resistor

In recent years, the concept of the negative resistor (NR) has been proposed and applied in the magnetic coupled wireless power transfer (MC-WPT) system to improve the stability of power transfer. However, it remains a fundamental challenge to find the characteristic differences and applications of the four basic NR-based MC-WPT topologies. In this paper, the circuit models of the four basic NR-based MC-WPT topologies: series-series (SS), series-parallel (SP), parallel-parallel (PP), and parallel-series (PS) are established, and their characteristics are analyzed and compared by using circuit theory, which enables engineers to determine and select topologies to suit different applications and requirements. Theoretical analysis shows that the compensation methods of the transmitter and receiver of the NR-based MC-WPT system would affect the operating frequency and output characteristics of the system. Moreover, by comparative analysis, the conditions and applicable ranges for a stable output of different topologies were provided. Finally, the experimental prototypes are set up by using the power electronic inverter and operational amplifier, and the voltage gain ratios of the four basic NR-based WPT topologies under the variations of transfer distance and load are observed. The experimental results validate the correctness of the theoretical analysis.

The Voltage stability analysis for grid-connected PV system using optimized control tested by IEEE 14 &30 bus system

In the research work presented in this paper, we present a grid-connected solar photovoltaic (PV) system, which is focused on various factors, such as the low oxide emission and high energy efficiency of the system. Solar PV systems have a greater impact on grid stability than any other energy source. IEEE 14 bus test system is used to verify the voltage stability of the bus. It is a concept of a methodology using a RNN-based PV controller in conjunction with a Landsman converter to maintain the PV system's voltage-gain ratio and improve it. Conversely, an ANN-based boost Integrated Landsman Converter improves the solar photovoltaic voltage connected to the grid. In addition, continuous monitoring of solar plants (irradiation, sunlight & voltage) is implemented through the Internet of Things (IoT). A grid voltage stability and analysis is taken by 14 buses, five generators and 12 loads test system is tested. The proposed two methods have been proven to be effective regarding the uncertainties related to loading demand. This approach offers voltage stability for grid-connected PV systems in industrial sectors. The IEEE 14 & 30 bus system tested this work using MATLAB simulation.

A new double mode control strategy for power router with very wide DC voltage range

AbstractIn household applications, the power router is a cost‐effective device for AC/DC power conversion. To make it compatible with various types of DC loads without introducing extra power conversion stages, it is important that the power router can work in an extremely wide DC voltage range. However, this poses great challenges for the controller design. To address this concern, a double mode control scheme is proposed. The high frequency resonant DC/DC converter is employed together with a DC/AC converter to form the power router. Its circuit features on voltage gain and active power ratio are presented to guide the accurate controller design. Mode I is designed to ensure the high efficiency DC/DC conversion while the desired output DC voltage of power router is tracked by a DC/AC converter. For mode II, the phase shift scheme is triggered to eliminate the loss induced by the reactive power, and the desired output DC voltage is adjusted by DC/DC converter. Mode I and II cooperate to guarantee the wide DC voltage range to satisfy different load requirements. The experimental validation in a lab‐scale power router prototype shows that the proposed scheme not only provides extremely wide voltage range, but also guarantees high efficiency by effectively tracking the resonant frequency.

A Comprehensive Review and Analytical Comparison of Non-Isolated DC-DC Converters for Fuel Cell Applications

The use of renewable energy sources such as solar photovoltaic, wind, and fuel cells is becoming increasingly prevalent due to a combination of environmental concerns and technological advancements, as well as decreasing production costs. Power electronics DC-DC converters play a key role in various applications, including hybrid energy systems, hybrid vehicles, aerospace, satellite systems, and portable electronic devices. These converters are used to convert power from renewable sources to meet the demands of the load, improving the dynamic and steady-state performance of green generation systems. This study presents a comparison of the most commonly used non-isolated DC-DC converters for fuel cell applications. The important factors considered in the comparison include voltage gain ratio, voltage switch stress, voltage ripple, efficiency, cost, and ease of implementation. Based on the comparison results, the converters have been grouped according to voltage level applications, with low voltage applications being best served by converters such as DBC, DuBC, TLBC, 2-IBC, 1st M-IBC, PSOL, SEPIC, and 1st M-SEPIC owing to their lower cost, smaller size, and reduced switch stress. Medium voltage applications are best suited to converters such as TBC, 1st M-TLBC, 2nd M-TLBC, 4-IBC, 1st M-IBC, 2nd M-IBC, 1st M-PSOL, 2nd M-PSOL, 1st M-SEPIC, and 2nd M-SEPIC, which offer higher efficiency. Finally, high voltage applications are best served by converters such as TBC, 1st M-TBC, 2nd M-IBC, 3rd M-IBC, 3rd M-PSOL, 4th M-PSOL, 2nd M-SEPIC, 3rd M-SEPIC, and 4th M-SEPIC.

A new transformerless DC/DC converter with dual operating modes and continuous input current port

AbstractIn this work, a transformerless DC/DC converter is presented with dual operating modes buck–boost procedure. As a simple structure and continuous input current port, the system acts as a common ground between the output and input terminal. One operating mode, quadratic voltage gain ratio is D/(1‐D)2, and other mode is D/(1‐D). In the present study, the continuous conduction mode (CCM), steady‐state conditions were assumed to analyze efficiency and small‐signal modeling by replacing parasitic resistance effects. The findings revealed that in comparison with other buck‐boost converters, the two voltage gain ratios were provided with fewer components and lower total switching device power in dual operating modes. Therefore, proposed converter can attract considerable attention for renewable energy applications, especially photovoltaic systems. Ultimately, the experimental findings of a prototype made in the laboratory are provided along with the received waveforms from the simulation in PLECS for validation purposes.

A Quadratic Buck-Boost Converter With Continuous Input and Output Currents

This study proposes a novel DC-DC converter topology that features a quadratic buck-boost voltage gain ratio. The quadratic gain of the converter enables it to achieve superior step-down or step-up capability when the duty cycle is higher or lower than 50 percent, as compared to conventional buck-boost converters. While there exist other quadratic buck-boost converters in the literature, the proposed converter offers unique features such as continuity of input and output currents, which reduces the current stress on the input and filter capacitors, making it a suitable option for renewable energy applications. Additionally, unlike its counterparts that have two high-side switches, the proposed converter features only one high-side and one low-side switch, allowing for a simpler gate-driver design. The proposed topology shares a common ground between the load and the source, and has the lowest stored energy with the same performance, indicating a compact size. Steady-state analysis has been conducted in both continuous and discontinuous conduction modes, and the controller design was studied with the aid of small-signal modelling. Simulation and experimental results from a 100 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">W</i> prototype were used to validate claims and analyses.

ZVT High Step-Up Boost Converter With Wide Input Voltage and Wide Output Power for Renewable Energy Applications

In this article, a high-efficiency, high step-up dc–dc converter is introduced by utilizing a new soft-switching circuit based on the zero-voltage transition (ZVT) technique. Soft-switching performance is independent of the output load and input voltage. The simple auxiliary circuit benefits from a low number of components. The resonant circuit comprises merely one switch and one small capacitor, and in comparison to the existing ZVT high step-up converters, no extra auxiliary diode and resonant inductor are used to provide soft switching. The proposed auxiliary circuit can be applied to coupled inductor (CI)-based step-up topologies, because of exploiting the leakage inductance of the CI cell in the resonant network. Providing soft-switching performance for all the semiconductor elements alleviates the reverse recovery and switching losses, which considerably enhances the efficiency. The proposed topology is a competitive structure in terms of efficiency, voltage gain ratio, and the number of components due to the mentioned features. The theoretical results are validated on a 200-W laboratory prototype with a 400-V output voltage.

An Improved Switched-Inductor and Switched-Capacitor Networks-Based High-Step-Up-Ratio DC–DC Converter

Achieving higher voltage at load side is essential in many applications, especially in small-scale solar PV systems. Traditional boost converter fails to lift the voltage level beyond five times due to saturation in the passive elements. In order to attain high voltage gain ratio, a novel switched-inductor and switched-capacitor networks-based high-gain step-up converter is proposed in this paper. It can attain higher voltage gain at lower duty ratios, thereby reducing the losses associated with the converter and enhancing the efficiency. The detailed analysis of the proposed converter has been made under the CCM and DCM conditions. Moreover, investigation on device stresses is carried out and the results are compared with recently derived converters. Also, the performance comparison of the proposed converter with other published topologies is presented in this paper. In order to validate the operation details, the measured results are presented and the same have been confirmed with the theoretical approach. Furthermore, experimental works have been carried out and the results are presented to confirm the feasibility of the operation.

Analysis of Grid-Interactive PV-Fed BLDC Pump Using Optimized MPPT in DC–DC Converters

In solar photovoltaic (PV) system-based Brushless DC (BLDC) motors for water pumping application, the role of DC/DC converters is very important. In order to extract the maximum power from the PV array, an efficient DC/DC converter is essential at the intermediate stage. In this work, different DC/DC converter topologies suitable for BLDC motors are proposed. The converters are supported by an optimized maximum power point tracking system to provide a reliable operation. Recent optimization algorithms such as fuzzy logic, perturb and observe, grey wolf, and whale optimization are implemented with the PI controller in maximum power point tracking to maximize the conversion efficiency. The obtained results using SEPIC, LUO, and interleaved LUO converters provide a comparative study in the case of converter output, motor parameters, and grid output. The performance analysis on three different converters and multiple optimization methods are carried out. By analyzing the performance of different converter topologies, the interleaved LUO converter outperforms the other two converters with the results of a voltage gain ratio of 1:22, conversion efficiency of 98.3%, and grid current THD of 2.9%. Moreover, regarding the power quality aspect, the total harmonic distortion of the grid current is maintained below the IEEE-519 standard. In addition, the developed system has an advantage of operating both in stand-alone and grid-connected operation modes.

Multiphase Low Stresses High Step-Up DC–DC Converter With Self-Balancing Capacitor Voltages and Self-Averaging Inductor Currents

Voltage gain ratio is a key limitation faced by nonisolated dc–dc converters in practical applications. Low voltage and current stresses, small volume, simple sampling control circuit, low cost, suitability for high power, scalability, and modularization are optimization trends of the dc–dc converter design. To improve the above-mentioned performance, a multiphase high step-up dc–dc converter is proposed, with advantages of high voltage gain, low switching voltage stresses, low switching current stresses, low capacitor voltage stresses, low output voltage ripple, capacitor voltages self-balancing feature, inductor currents self-averaging feature, ease of extension, and being able to be modularized. The topology derivation, comparisons with other high step-up converters, the operating principle, characteristics, and mathematical models of the proposed converter are studied in detail. Finally, a laboratory prototype of the proposed dc–dc converter operating from 400 to 800 W is built and implemented with input being 24 V and output being 400 V. The experimental results verify the feasibility and superiority of the proposed converter. The proposed multiphase high step-up converter is suitable for the applications, such as fuel cells, electric vehicles, energy storage systems, photovoltaic systems, and microgrids.

A new transformerless quadratic buck–boost converter with high‐voltage gain ratio and continuous input/output current port

A new transformerless quadratic buck–boost converter with a common ground and a high-voltage gain ratio of D/(1−D)2 is proposed in this study. The output and input currents of the proposed structure are continuous due to the presence of inductive filters in the output and input ports. The continuity of the output current simultaneously reduces the voltage ripple and also the capacitor stress at the output port. With the proposed quadratic structure, a lower total switching device power and a higher voltage gain ratio are attained at the same duty cycle. Due to the advantages of the proposed structure, it can be widely used with renewable energy. The presented model is investigated in terms of steady-state analysis, continuous conduction mode, small-signal modelling, and efficiency with parasitic resistance effects. To validate the performance of the proposed converter, experiments are conducted in the laboratory to claim the theoretical waveforms obtained from the piecewise linear electrical circuit simulation (PLECS) simulation.

A Novel High Voltage Gain Buck-Boost Converter with Dual Mode Boost

This paper focuses on introducing a transformerless DC/DC converter with low total switching device power in dual working modes including step-up and step-up/down modes. The proposed converter is analysed in terms of the continuous conduction mode, steady state, and efficiency with the replacement of parasitic resistance effects. The proposed converter in the step-up mode has a high voltage gain ratio and a continuous input current. Then, the other working mode of the proposed converter with relevant DC/DC converters is compared. By this comparison, the proposed converter has a high voltage gain ratio. Also, the converter characteristics such as voltage stress on power switches and charge pump capacitors are in a good condition in this mode. Finally, the experimental results from a laboratory made prototype and the obtained waveforms from the simulation in PLECS are presented for validation such as higher voltage gain ratio, lower total switching device power and better efficiency. &nbsp;

A Non-Isolated DC-DC Converter with Dual Working Modes and Positive Output Voltage

In this paper, a positive output DC/DC converter with low total switching device power in dual working modes is introduced. One working mode is a step-up mode (boost), and other is a step-up/down mode (buck-boost). The proposed converter in step-up mode has high voltage gain ratio, low stress on switches, and continuous input current. In other working mode, the buck-boost converter with six relevant DC/DC converters is compared. By this comparison, it can be seen that the proposed converter has a lower voltage gain ratio, but instead the converter characteristics such as voltage stress on power switches and charge pump capacitors are in good condition for this mode. The proposed converter is analyzed in terms of the continuous conduction mode (CCM), steady state and efficiency with replacement of parasitic resistance effects. To validate the performance of the proposed converter experiments are conducted in the laboratory to claim the theoretical waveforms obtained from the PLECS simulation.

A non‐isolated high voltage gain DC–DC converter based hybrid switched LC network for renewable energy applications

AbstractThis paper presents a new high voltage gain DC–DC converter for renewable energy applications without the need for a galvanic isolation. The converter combines the active switched‐inductor network and the switched‐capacitor network to boost the voltage gain ratio without a high duty ratio. The presented converter uses clamping capacitors to minimize the maximum voltage stress of the power‐switching devices; hence, low power rating devices can be employed. Furthermore, the converter operates at a high switching frequency. Therefore, the use of small inductors and capacitors is the main advantage. The paper describes in detail the operating mode and design procedures of the converter. Additionally, the associated power losses and the efficiency are calculated. A 200‐W laboratory prototype was fabricated, and experimental results verified the theoretical analysis.

A non‐isolated switched inductor‐capacitor cell based multiple high voltage gain DC‐DC boost converter

AbstractIn this paper, a non‐isolated switched inductor cell integrated high step‐up voltage gain DC‐DC converter with a charge pump mechanism is discussed. The continuous conduction mode of the input current is a beneficial aspect of this converter, which is appropriate for electric vehicles, renewable energy, and LED applications. The proposed converter works in two distinct operating modes and provides a flexible range of voltage gain ratios. The performance and small‐signal modeling of the converter in continuous conduction mode are extensively investigated, and voltage gain calculations for the two operational modes are derived. The Markov technique is used to evaluate the converter reliability, component failure rates, and mean time to failures. The proposed converter is evaluated with the existing converters in terms of voltage, and current stress of each component, voltage gain, total component stress factor, component count, and reliability. The proposed converter's hardware prototype has been developed. To validate the theoretical calculations, the converter's simulation and experimental results are discussed. The converter has a maximum output voltage of 110 V and a switching frequency of 50 kHz. The converter's peak efficiency is 94.5%.

A Common Ground Four Quadrant Buck Converter for DC-AC Conversion

With the increasing stand-alone and grid integrated low power renewable energy generation, the use of non-isolated DC-AC converters has increased multifold. However, the non-isolated power conversion with conventional DC-AC converters can cause high leakage currents due to parasitic capacitances. To resolve this problem, research on common ground converter topologies is gaining significance. This paper presents a novel single-phase DC-AC converter with common ground for the input and output terminals. There are only minor modifications required in comparison to the topology of the commonly used conventional H-bridge inverter for DC-AC conversion. In addition, the basic components and their counts remain the same. The gain ratio of the proposed inverter is such that it reduces the effect of switching delays. The availability of common ground for DC input and AC output sides provides the advantage of zero common-mode voltage and avoids leakage currents due to parasitic capacitances. The voltage gain ratio of the proposed converter is superior compared to the H-bridge inverter. Further, the switch stresses, switch utilization ratio and ratings of the constituent components have been derived for an accurate design of the converter. The proposed converter is observed to be more preferable when compared with other converters and modulation techniques for leakage current elimination based on the number of components and complexity of the circuit and control. The simulation and experimental results for different loads and load changes are presented to verify the theoretical claims. It is capable of supporting real and reactive power while operating competently under sudden changes in load. Therefore, the proposed common ground DC-AC converter can replace the H-bridge by modifying its circuit or replacing it with readily available half-bridge modules to obtain zero common-mode voltage and leakage currents. Hence, it is particularly attractive for low-power renewable generation and energy storage system applications.

A Novel Full Soft-Switching High-Gain DC/DC Converter Based on Three-Winding Coupled-Inductor

In this article, a new nonisolated full soft-switching step-up dc/dc converter is introduced with a continuous input current for renewable energy applications. The use of a three-winding coupled-inductor (TWCI) along with a voltage multiplier, enables the proposed converter to enhance the voltage gain with lower turns ratios and duty cycles. Also, a lossless regenerative passive clamp circuit is employed to limit the voltage stress across the power switch. In addition to zero current switching performance at the turn-on instant of the power switch, the turn-off current value is also alleviated by adopting a quasi-resonance operation between the leakage inductor of the TWCI and middle capacitors. Moreover, the current of all diodes reaches zero with a slow slew rate, which leads to the elimination of the reverse recovery problem in the converter. Soft-switching of the power switch and all the diodes in the proposed converter significantly reduces the switching power dissipations. Therefore, the presented converter can provide a high voltage gain ratio with high efficiency. Steady-state analysis, comprehensive comparisons with other related converters, and design considerations are discussed in detail. Finally, a 160 W prototype with 200 V output voltage is demonstrated to justify the theoretical analysis.

Design and Implementation a Single-Switch Step-Up DC-DC Converter Based on Cascaded Boost and Luo Converters

We designed and implemented a single-switch step-up DC-DC converter based on cascaded boost and Luo converters. The proposed converter demonstrated a quadratic voltage gain and a high efficiency, which makes it suitable for renewable energy applications, where a high voltage gain ratio is desired without imposing a high number of bulky items or employing a high duty cycle of the active switches. This converter benefits from the continuity of the input current waveform, which equips the maximum utilisation of renewable energy sources. While a transformer-less high voltage-gain was achieved, the voltage and current stresses of the power switch and diodes were kept low in comparison with the existing quadratic DC-DC converters. We analysed the converter in both continuous and discontinuous conduction modes. A non-ideal model of components was considered for power loss and efficiency calculations and comparisons. Finally, the simulation results were extracted with PLECS and validated with experiments on a 120 W prototype.

Pseudo DC-Link EV Home Charger With a High Semiconductor Device Utilization Factor

This article proposes a bidirectional battery charger for grid to vehicle and vehicle to grid operations of electric vehicles (EV). The dc stage of the proposed converter offers a quadratic buck–boost voltage gain ratio, which makes it suitable for interconnecting the battery pack unit of EVs with both dc and ac grids as a home EV charger. A high-voltage gain ratio, low voltage, and current stress of switches, high values of utilization factors (UF) for both directions are achieved. Continuous input current and common electrical ground are preserved at the dc–dc stage and also, the continuous output current of the proposed converter makes the realization of the pseudo dc-link method possible for connecting to an ac grid. Consequently, the switching power loss in the dc–ac stage of the EV charger is reduced, and as a result, it allows the proposed charger to run more efficiently and cooler. The operating principle, steady-state characteristics including the current, voltage stress, and UF of the switches, and comparison with other state-of-the-art dc–dc bidirectional converters are carried out in detail. Finally, to verify the theoretical achievements, a 500-W laboratory prototype of the proposed EV charger is implemented. The EV charger exhibits the capability for ac and dc regulation and demonstrates peak efficiency of 97.8% in the forward and 97.5% in the backward direction modes of operation.