Search

A dual switches high step‐up DC–DC converter with coupled inductor (CI) and voltage multiplier cell (VMC) is proposed in this paper. The gate pulses of the switches are synchronized with each other. During ON state of the switches, the CIs are charged in parallel through the input power source and during OFF state of the switches, they are discharged to the output in series. The energy of the leakage inductances is recycled by the passive clamp circuit. The passive clamp circuit for one of the metaloxidesemiconductor field‐effect transistor (MOSFETs) is integrated with the VMC. In such a case, the clamp circuit participates in voltage gain extension which facilitates the utilization of lower number of the components, as well. Meanwhile, the MOSFETs and diodes are turned ON and turned OFF with zero current switching (ZCS) performance which reduces the switching losses. Through the dual switches concept and implementation of the CI VMC, the advantages such as high voltage gain, low voltage stresses across switches and distributed current stresses between MOSFETs are achieved. The steady‐state analysis of the proposed converter is provided which is followed by a comparison with some published converters. Finally, a 300 W 25V to 400 V laboratory prototype is fabricated and tested to verify the performances. [ABSTRACT FROM AUTHOR]

This paper proposes a soft‐switching high step‐up DC/DC interleaved boost converter. The converter uses an interleaved structure to decrease input current ripple. The coupled inductor technique achieves high voltage gain without needing the extremely increased duty cycle. The applied auxiliary circuit provides zero‐voltage‐switching (ZVS) condition for both main switches with a minimum number of elements. In addition, all the diodes turn off with zero‐current‐switching (ZCS), alleviating the reverse recovery problem. Moreover, all power switches and diodes have low voltage stress. The voltage stress of the auxiliary switch is low, resulting in low Coss losses of the auxiliary switch. The other properties of the proposed converters are continuous‐low‐ripple input current, no need for the floating gate drive, and small size. The theoretical analysis is validated by a 250‐W prototype with 40‐V input to 400‐V output voltage with a 100‐kHz.switching frequency. [ABSTRACT FROM AUTHOR]

In this article, a novel soft switched interleaved boost structure with a simple auxiliary circuit is proposed which is suitable for stand-alone loads or ac grid applications. In this topology, coupled inductors and switched capacitor cells of parallel modules are merged to obtain high voltage conversion ratio. The converter also has the capability of adding extra switched capacitor cells to attain very high voltage gain. To provide soft-switching condition in the wide range of output power, a new zero-voltage transition auxiliary circuit is employed which is responsible for soft switching of both phases and benefits from low conduction losses, the minimum number of semiconductor elements, and only one auxiliary gate-driver. These merits provide very high efficiency at both full-load and light loads. More importantly, no auxiliary magnetic components are utilized by taking advantage of the leakage inductance of coupled inductors for the resonant network. All semiconductor components operate under soft switching alleviating the reverse recovery problem and switching losses. Besides, the converter benefits from common ground between input and output which simplify voltage feedback. The experimental results of the interleaved converter prototype with 400-V output voltage at 400 W and 100 kHz switching frequency are provided. The full load efficiency of 98% was achieved and the power density was observed 1.9 W/Cm3. [ABSTRACT FROM AUTHOR]

An interleaved high step-up converter topology based on the coupled inductor (CI) and built-in transformer (BIT) is proposed in this study to provide high step-up voltage gain and high efficiency with a low number of power electronic components for renewable energy applications. The voltage gain is increased by both of the turns' ratio of CI and BIT, so there is no need to extend duty ratio to obtain high voltage gain. The proposed topology is much more flexible than those with only either CI or BIT. Moreover, the voltage stress across semiconductor devices can be relatively decreased by adjusting the turns' ratio of the CI and BIT. In addition, the input current ripple can be reduced when the interleaved structure is applied at the input of this converter. Furthermore, turned-OFF and turned-ON zero current switching (ZCS) conditions for the diodes and power MOSFETs are achieved, respectively, thanks to the leakage inductances of the magnetic devices. Hence, due to the control of the falling current rate of the diodes by the leakage inductances, reverse recovery problem is alleviated. Moreover, the energy of the leakage inductances is recycled by the clamp capacitors avoiding high spikes across MOSFETs. As a result, according to the abovementioned advantages of the proposed converter, MOSFETs with low ON-state resistance and diodes with low forward voltage drop can be used to decrease the conduction losses. A 600 W laboratory prototype with 27–400 V voltage conversion at switching frequency 50 kHz is built to verify the performance of the proposed converter. Experimental results confirm the theoretical analysis. The efficiency reaches to 94.6% at full load which is close to the calculated of 95.8%. [ABSTRACT FROM AUTHOR]

A novel zero voltage switching (ZVS) interleaved high step-up converter for renewable energy systems is proposed in this article. By applying a switched capacitor mixed with coupled inductor and built-in transformer, the proposed converter achieves high voltage gain and minimized voltage stress across power switches. Both of the voltage gain and the voltage stress can be adjusted by the turns ratio of the coupled inductor and built-in transformer, which gives an extra degree of freedom for the converter design. Hence, operating at high duty cycles is avoided and low voltage rated semiconductors can be adopted, which reduce conduction losses and improve the circuit performance. Furthermore, an active clamp scheme is utilized to guarantee ZVS turn-on for the power MOSFETs and the leakage inductances of the magnetic means help to provide zero current switching of the diodes. In such a case, switching losses are minimized and the reverse current recovery is alleviated. Accordingly, the proposed converter with reduced counterparts is a suitable candidate for high step-up and high power applications. Finally, a 600-W prototype with 24 to 480 V voltage conversion is built to demonstrate the performance of the proposed converter. [ABSTRACT FROM AUTHOR]

In this paper, an interleaved zero voltage switching high step‐up converter based on active clamp, coupled inductor (CI), built‐in transformer (BIT), and switched capacitor (SC) is proposed. The main novelty of the proposed converter is that the secondary winding of the CI is inserted between the primary winding of the CI and the primary winding of the BIT. Therefore, the voltage gain can be achieved in proportionate to the multiplication of the turn ratios of the CIs and BIT. The configuration of the proposed converter not only increases the voltage gain, but also reduces the current and voltage stress of the power switches and restricts the input current ripple, which decreases the conduction losses and increases the lifetime of the input source. Also, zero voltage switching turn‐ON and turn‐OFF conditions for all switches are achieved by employing an active clamp configuration. The voltage across the diodes clamped to the output voltage and the reverse recovery problem is reduced due to the leakage inductors. Finally, a 600 W prototype with 24–400 V voltage conversion is built to verify the performance and theoretical analysis. [ABSTRACT FROM AUTHOR]

This paper proposes an interleaved zero‐voltage switching (ZVS) ultra‐large gain converter. By implementing coupled‐inductor (CI) and built‐in transformer (BIT) together with a switched capacitor (SC) voltage multiplier cell (VMC), a higher degree of flexibility is achieved for improvement of step‐up voltage gain in comparison with those in which only one of these magnetic devices is utilised. Furthermore, the imposed voltage across the semiconductors is reduced by adjusting the turns ratio of the implemented CI and BIT. To further improve the efficiency, semiconductor devices with low ON‐state resistance can be used. Moreover, to ensure ZVS turn‐on, active clamp circuits are located in parallel with the main MOSFETs, which realize ZVS for all MOSFETs during an entire switching cycle. Minimizing the input current ripple as well as attenuating the reverse recovery problem of the diodes are the other advantages of this converter. Therefore, the proposed converter is a suitable candidate for those applications requiring high step‐up gain and high conversion efficiency, such as renewable energy systems. To validate the performance of the proposed converter, a 600 W prototype with 22–380 V voltage conversion is designed, fabricated, and tested. Experimental results confirm that the proposed converter outperforms the previously presented ones in terms of the voltage gain and efficiency. [ABSTRACT FROM AUTHOR]

In this article, we propose a novel interleaved high step-up converter. The proposed converter integrates the built-in transformer voltage multiplier cell (VMC) to the interleaved boost converter with voltage lift capacitor. The voltage gain is increased by both of the turns ratio of the built-in transformer and the voltage lift capacitor. Hence, there is no need to operate the converter around unity duty cycles to obtain high voltage gains. Meanwhile, the voltage stress across semiconductors is reduced considerably, facilitating the utilizing of mosfets with low on-state resistance and diodes with low forward voltage drop decreasing the conduction losses. The leakage inductance of the built-in transformer not only provides zero current switching (ZCS) for mosfets but also controls the falling current rate of the diodes alleviating the reverse current recovery problem. In addition, the energy of the leakage inductance is recycled by the clamp capacitor avoiding high spikes across switches. In comparison with the recently published converters, the proposed converter introduces all of the abovementioned advantages with a low number of components that make it an interesting solution for high efficiency and high step-up applications. Finally, a 40-V to 580-V prototype with 930 W power is fabricated to explore the merits of the proposed converter. [ABSTRACT FROM AUTHOR]

By inserting the secondary windings of the coupled inductors in series with the primary of the built‐in transformer at the middle branch, a new concept is introduced for achieving ultra large voltage gain. The secondary and tertiary windings of the built‐in transformer are inserted in the voltage multiplier cell. This configuration not only extends the voltage gain and minimises the voltage stress across power MOSFETs, but also gives a more flexibility to increase the voltage gain by the turns ratios of the built‐in transformer and coupled inductors. Hence, high duty cycle is avoided and low voltage switches can be adopted which reduces the conduction losses. Also, the regenerative diode in each of the phases is connected to the other phase to improve equal current sharing performance. The energy of the leakage inductances is recycled by passive clamps and the high voltage spikes are avoided. Meanwhile, due to the leakage inductances of the magnetic means, the zero current switching of semiconductor devices is provided and the reverse recovery problem is alleviated. Finally, a 600 W prototype with 28–400 V voltage conversion and 97% conversion efficiency is built to demonstrate the performance of the converter. [ABSTRACT FROM AUTHOR]

A high step voltage ratio converter is introduced in this study. In order to improve the voltage gain and the voltage stress of semiconductors, coupled‐inductor (CI) combined with built‐in transformer (BIT) and voltage multiplier cell are employed. Therefore, comparing with previously presented converters in which only CI or BIT structure was used, a greater degree of freedom is obtained. Consequently, the low voltage rated semiconductors can be utilised which in turn decrease the conduction losses. To deal with the ringing phenomenon and reverse recovery problem, zero‐current switching turn‐on/turn‐off are well achieved for switches/diodes via leakage inductances of magnetic means. Moreover, by employing passive clamps, leakage energy is recycled. Furthermore, due to the interleaved structure, the input current ripple is considerably diminished. In addition, the share of input current between different phases is equitable as a result of the charge balance of capacitors. With all these in mind, the proposed structure is a good candidate for high current and high power applications. Finally, in order to validate the effectiveness of the proposed topology, a 600 W 24 V/480 V laboratory prototype is fabricated. [ABSTRACT FROM AUTHOR]

This study presents a current‐auto‐balance non‐isolated interleaved high step‐down converter with a coupled inductor. The proposed converter achieves low‐voltage gain by the turns ratio of the coupled inductor and capacitive voltage division which avoids low duty cycles. The voltage stress across the power MOSFETs is decreased and the voltage stress across the diodes is controlled by the turns ratio of the coupled inductors. Therefore, low voltage semiconductors are adopted reducing the switching and conduction losses. Meanwhile, the zero current switching (ZCS) turn‐ON for MOSFETs and ZCS for whole switching transitions of diodes are provided by the leakage inductances that reduces the switching losses and alleviates the reverse recovery problems. Besides, by replacing the inductors with the coupled ones, the power density is improved. Due to the interleaved structure, the output current ripple is minimised and the thermal stress is distributed between the phases. All of these factors improve the conversion efficiency and overall performance of the proposed converter. Moreover, the auto‐current‐sharing performance is realised due to the charge balance of the blocking capacitors. Finally, a 400 W prototype with 400–25 V voltage conversion is fabricated to demonstrate the performance of the proposed converter. [ABSTRACT FROM AUTHOR]

A zero voltage switching (ZVS) interleaved high step‐up converter with coupled inductor and built‐in transformer voltage multiplier cell is introduced in this study. A more flexible design is provided by increasing the voltage conversion ratio by utilising the turns ratios of the coupled inductor and built‐in transformer. The ZVS operation of the metal‐oxide‐semiconductor field‐effect transistors (MOSFETs) and absorption of the leakage current are realised through active clamp circuits. Furthermore, the voltage stress across the switching devices is minimised that give rises to implementation of low voltage rated MOSFETs and consequently low conduction losses. Meanwhile, the diode reverse current problem is alleviated by the leakage inductance of the coupled inductor and built‐in transformer. All of the abovementioned advantages make the proposed converter as a high efficiency candidate for high current and high step‐up applications. Finally, a 600 W, 48–700 V voltage conversion with the conversion efficiency of 97% is fabricated to probe the merits of the proposed converter. [ABSTRACT FROM AUTHOR]

This article proposes a novel interleaved high-step-up dc–dc converter with zero voltage switching (ZVS). Through a built-in transformer voltage multiplier cell (VMC) the high voltage conversion ratio is achieved without the narrow duty. By applying active clamp scheme, all of the power MOSFETs are switched with ZVS which minimizes the switching losses of the proposed converter. Besides the voltage stress across the switches is decreased and can be controlled by the built-in transformer turns ratio enabling utilization of low on-state resistance and low forward voltage drop semiconductors. Due to the interleaved structure, the input current ripple is minimized and the thermal stress is shared between the phases. Meanwhile, the charge balance of the capacitors give rise to equal current sharing performance for the two input inductors. All of these factors reduce the power losses and improves the performance of the proposed converter. Finally, in order to verify the operation of the proposed converter, a 35-V input voltage to 500-V output voltage prototype with the rated power of 1 kW is fabricated and tested in the laboratory. [ABSTRACT FROM AUTHOR]

Nowadays, the integration of renewable energy sources, as distributed generation, into power systems is accelerated, and the corresponding technological development is evolving at a frantic pace. The power industry is going to reach a turning point for increasing the penetration of these sources due to concerns pertaining to climate changes and world-wide ever-growing demand for energy. The pervasive renewable energy in small-scale poses new challenges for operators to manage an abundant number of small-scale generation sources, called microsources. The current banking structures are unable to handle such massive high-frequency transactions. Thus, the incorporation of cryptocurrencies is inevitable. Besides, the utilization of IoT-enabled devices produces a large body of data that must be securely transferred, stored, processed, and managed to boost the grid’s observability, controllability, and autonomy. Artificial intelligence and big data techniques should be used to analyze the data for quasi-real-time decision making. This study delves into the aforementioned controversial challenges and opportunities, and the corresponding solutions for the incorporation of IoT and blockchain in power systems, particularly in the distribution level, residential section, smart buildings, smart homes, energy hubs schemes, and the management of residential electric vehicle supply equipment are addressed. [ABSTRACT FROM AUTHOR]

In this study, a new non-isolated interleaved bidirectional DC-DC converter with a high step voltage ratio based on coupled inductors (CIs) is introduced. The CIs significantly increase the voltage conversion ratio and provide soft-switching conditions for the switches at turn-on instant. Also, employing an interleaved structure combined with the CI in the low-voltage side noticeably reduces the current ripple and this feature has a vital role in the high-power applications. Also, this topology provides auto-current sharing for the two phases of the interleaved structure. The CIs in the high-voltage side, supply a steep gain in both buck and boost modes with an appropriate duty cycle. The proposed method provides zero current switching (ZCS) turn-off condition for all diodes and ZCS turn-on condition for all switches without requiring any auxiliary circuit. So the undesirable reverse recovery effects of diodes are considerably reduced. The proposed converter has the minimum number of switches for two-phase bidirectional structures. Also, a simple passive clamp circuit is proposed for the converter to limit the voltage spikes of CIs. Finally, a 600 W, 30/300 V laboratory prototype is implemented to verify the performance. [ABSTRACT FROM AUTHOR]

Impulse noise reduction has been a challenge for Image Processing researchers for many decades. Median filter had been the most popular denoising methods. However, owing to its edge jittering and removing image detail properties, numerous efforts have been taken in order to improve its performance. Median ϵ-filter is one of the modified median filters. Median ϵ-filter and median filter behave in a like manner in the presence of noise. Thus, it has all disadvantageous things of median filter. In this article, we improve median ϵ-filter's efficiency by giving weights to the outcomes of ϵ-filter. The experimental results show the excellent performance of our method. Other than that, in the absence of noise, our method preserves the original image's details more than others. [ABSTRACT FROM PUBLISHER]