In this article, a new bridgeless single-phase buck-boost power factor correction (PFC) converter with one magnetic core is introduced. The proposed converter is designed to operate in discontinuous ...capacitor voltage mode (DCVM) to achieve low total harmonic distortion (THD) and continuous input current with a simple structure. The DCVM operation gives additional advantages, such as inherent PFC, low turn- off losses, and reduced complexity of the control circuitry. Unlike the buck converter, the proposed converter eliminates the dead angle of input current without adding any extra circuits. Also, by eliminating two input diodes in power flowing path, the efficiency is further improved. Due to achieved almost zero current switching at the turn- on and almost zero voltage switching at the turn- off , the switching losses are eliminated. In this article, theoretical analysis and principal operation of the converter are discussed. An experimental prototype is implemented to verify the performance of the proposed converter. Experimental results are presented for a 120-W prototype at 110-V rms input and 48 - V output.
In this paper, a new nonisolated high step-down dc-dc converter with ultrahigh step-down conversion ratio is proposed. Advantages of the proposed converter are high step-down ratio, extended duty ...cycle, reduced switching losses by a converter operation under zero-voltage switching (ZVS) conditions, reduced reverse recovery losses of diodes by achieved zero-current switching turn-off condition, and reduced voltage spikes by the inherent active-clamping structure of the converter. In this converter, series capacitors and coupled inductors have been used in power path to achieve the low voltage gain and extended duty cycle. By the inherent active-clamping structure of the proposed converter, the leakage inductance energy is totally recovered in the output; therefore, the high voltage spike across the semiconductor devices is suppressed. The switches of the proposed converter can operate under ZVS conditions, which cause reduced switching losses and improved efficiency. In this paper, the converter operating modes are discussed, and a prototype circuit is implemented. Experimental results are presented to verify the theoretical analysis.
Abstract This paper proposed a new two‐phase high step‐down DC–DC converter is proposed. This converter is derived from the two‐phase series‐capacitor converter. The proposed converter replaces the ...series capacitor with a new structure that integrates Valley‐Fill circuit and coupled‐inductors concepts. This replacement can improve the voltage gain of the converter as well as a considerable reduction of diodes voltage stress. The proposed structure implements a dual‐phase buck using a single magnetic element. Also, the proposed structure inherently limits the voltage spikes due to the leakage inductance of coupled inductors without any additional clamp circuit. The proposed converter is analyzed, and design guidelines are provided. A 300–24 V prototype converter is implemented to justify the validity of circuit operation and the theoretical analysis.
This paper proposes a new isolated single-stage single-switch soft-switching power-factor-correction (S6-PFC) driver without electrolytic capacitors for supplying light-emitting diodes (LEDs). In the ...proposed LED driver, all the semiconductor devices are soft-switched without employing any extra active switch. The leakage inductance of transformer acts as a resonant component so that the leakage energy is recycled. Soft-switching operation of the semiconductor devices together with absorption of the leakage energy improve the proposed driver efficiency. Furthermore, input current of the driver has very low harmonics resulting in high power-factor. Operating principles of the proposed S6-PFC LED driver as well as its design guidelines are presented. Also, experimental results of a laboratory prototype for supplying a 21 W/30 V LED module from 220 V/50 Hz ac mains are provided to verify the theoretical analysis. The presented results show that the implemented prototype has an efficiency of 92% under full-load condition and its input current total harmonic distortion is as low as 2.6%.
Here, a new single stage single switch soft switching PFC (power factor correction) converter is presented and analysed. The proposed converter combines buck AC‐DC converter and forward DC‐DC ...converter and applies an auxiliary circuit to eliminate input current dead angle. Furthermore, soft switching is attained and switching losses are eliminated resulting in high efficiency. Another merit of the proposed converter is the partial direct transmission of input power to the output that helps to improve efficiency. Experimental results are presented which justify the above mentioned points and show less than 5% THD in the nominal load. Comparison with other similar single stage PFC converters is performed and shows the proposed converter provides the lowest THD while high efficiency is attained.
This research proposes a cost‐efficient microinverter. The proposed microinverter can eliminate the leakage current using common‐ground configuration. It uses three switches and only one of them ...operates at high frequency. In addition, a passive lossless snubber is applied to limit voltage stress and provide soft‐switching performance for the high‐frequency switch. A pair of coupled inductors is used to provide higher voltage gain which makes it possible to keep the operating duty cycle in the normal range and makes the proposed inverter suitable for AC module application. The input current of the proposed microinverter is continuous which reduces the loss of the input capacitor by high‐frequency current component reduction. The operating principle of the proposed inverter is described in both positive and negative current modes. In positive current mode, the proposed microinverter works similar to SEPIC converter and in negative current mode its performance is similar to CUK converter. The dynamic behavior of the proposed microinverter is analyzed through simulation and a simple PI controller is designed to accommodate the worst case. Theoretical loss analysis is applied and finally the results of this research are compared with other researches. The performance of the proposed inverter is justified by simulation and practical results of a 300‐watts prototype.
In this paper a SEPIC/CUK microinverter is proposed that it can eliminate the leakage current using common‐ground configuration. It uses three switches and only one of them operates at high frequency. In addition, a passive lossless snubber is applied to limit voltage stress and provide soft‐switching performance for the high‐frequency switch.
This article presents a novel high step up converter based on the active switch inductor (ASL) technique for renewable energy source applications. The coupled inductor technique provides an ...opportunity to increase the gain. The proposed converter exploited the leakage inductors to provide zero current switching (ZCS) turn‐on for both switches. Therefore, there is no need for an auxiliary circuit, which simplifies the structure. Also, all diodes turn off under ZCS, which eliminates the reverse recovery problem and results in reduced switching losses. The energy of the leakage inductor is recycled, and the voltage spike on the switches is limited. In addition, all semiconductor voltage stresses are clamped below the output voltage. Hence, components with lower on‐resistance can be utilized to reduce conduction loss. Because of the reduction in power loss, the efficiency rises to 97.2% at 250 W output power. It also benefits from the current sharing of the interleaved structure. The operating principles, design considerations, and comparison to other topologies are discussed. To verify the effectiveness of the proposed converter, a prototype converter with 250 W of output power, 50 V of input voltage, 500 V of output voltage, and 100 kHz of switching frequency is implemented.
This paper presents a new high step up converter which is a very good option as the interface circuit of solar panels. The introduced converter has a simple structure while providing low conduction and switching losses resulting in high efficiency.
This study proposes a new interleaved high step‐up topology based on cross‐coupled inductors and voltage multiplier cells (VMCs). Two series capacitors in VMC are employed to raise voltage gain and ...diminish peak voltage across switches. Thus, low voltage MOSFETs with low on‐resistance (Rds(on)) can be used in the proposed converter. Due to the presence of the leakage inductors in coupled inductors, the falling rate of the output diodes current is controlled and the diode recovery current problem at turn‐off can be mitigated. In addition, switches are turned on under ZCS conditions which results in efficiency improvement. Using two‐phase topology reduces input current ripple and shares power losses between each phase. The converter is analyzed and its operation is investigated using detailed comparisons. Finally, to confirm the performance of the proposed converter, a 30 V input voltage to 400 V output voltage prototype with the rated power of 220 W is implemented and tested in the laboratory.
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.
This paper proposes a non‐isolated DC‐DC high step‐up converter. To achieve a high voltage conversion ratio and overcome the problems related to near unity duty‐cycle of the conventional boost ...converter in high step‐up applications, coupled‐inductors along with switch‐capacitor techniques are merged in this topology. The proposed converter provides continuous input current with low ripple without using any current ripple cancellation method and the voltage across the switch is limited inherently. In order to reduce the control circuit complexity, the proposed converter uses only one switch. These features decrease the complexity of the proposed converter structure. The voltage stress of the semiconductor components is reduced significantly; thus, high‐quality elements (fast power MOSFET switches with low on‐state resistance and Schottky diodes with low forward voltage drop along with low power losses) can be used, which minimizes the switching and conduction losses and improves the converter efficiency. To confirm the converter operation and theoretical analysis, a 200‐W prototype converter with 24‐to‐200‐V input and output voltages operating at 100‐kHz is implemented in the laboratory.
A coupled‐inductors‐based single switch high step‐up converter is proposed in this paper, which the voltage stress of their semiconductor components are reduced to less than the output voltage. Besides, the proposed topology provides continuous input current with low ripple and the voltage across the switch is limited inherently.
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