Voltage Stress Of Diodes Research Articles

Interleaved Boost-Integrated LC Series Resonant Converter With Frequency-Free Designed Transformer for Wide Voltage Range Applications

This paper presents a novel interleaved boost integrated LC series resonant converter with two output rectification modes, which are voltage-doubler rectifier mode and voltage-quadrupler rectifier mode with constant output voltage for wide input voltage range applications. Due to the symmetrical configuration of the rectifier, the voltage stress of switches and diodes on the secondary side are only half of the output voltage. With the proposed pulse frequency modulation, the maximum magnetic flux density <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B_m</i> of high frequency transformer is only related with the resonant frequency rather than the switching frequency. Hence, the transformer can be frequency-free designed. The zero-voltage-switching of the primary switches and zero-current-switching of the secondary switches and diodes are achieved, respectively. Moreover, the design procedure for some key parameters is presented. Finally, a 470 W prototype with a switching frequency range from 50 kHz to 140 kHz is built to verify the operation principles of the proposed converter and modulation.

Design of New Nonisolated High Gain Converter for Higher Power Density

A high gain nonisolated DC-DC converter using a single power semiconductor switch is proposed in this article. The operation of the proposed converter is explained under continuous conduction mode (CCM), discontinuous conduction mode (DCM), and boundary conduction mode (BCM). The mathematical expressions for steady-state voltage gain, voltage stress, and current stress of diodes and switch are provided. Also, the design of inductors and capacitors in the CCM mode is explained with appropriate mathematical equations. The proposed topology is tested with a 200 W prototype at 50 kHz and a 60% duty cycle. The dynamic behavior of the proposed converter is examined by changing the duty cycle value and also load values. The proposed converter is verified with experimental results to prove the effectiveness of its operation. The proposed converter provides higher steady-state voltage gain as compared with recently developed topologies. The efficiency and power density of the proposed converter is 90% and 1.16 kW/L, respectively.

Nonisolated Topology for High Step-Up DC–DC Converters

A new dc–dc converter structure with high voltage gain is proposed in this paper. The proposed converter consists of two switches that are turned on and off simultaneously. In addition, the two switched-capacitor cells and one energy storage cell are utilized in the structure of the proposed converter. These result in high voltage gains at low values of the duty cycle. Besides, the voltage stress across the power devices is low and below half of the output voltage. Therefore, the MOSFET switches with low <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$R_{\mathrm {DS-on}}$ </tex-math></inline-formula> and devices with reduced nominal voltage can be used in the proposed converter which in turn reduces the conduction and turn-on losses. The operating principles of the proposed topology are explained, and the analysis of voltage and current stresses of the devices is accomplished. The circuit performance is compared with other solutions in the literature in terms of voltage gain and normalized voltage stress of switches and diodes. Eventually, in order to verify the theoretical analysis, the experimental results are provided.

Quadratic-Extended-Duty-Ratio Boost Converters for Ultra High Gain Application With Low Input Current Ripple and Low Device Stress

A new quadratic extended-duty-ratio (EDR) non-isolated boost converter is introduced here for ultra-high gain applications. The proposed converter is a combination of EDR boost converter and conventional quadratic boost converter. Quadratic boost converters can achieve high gain with lower component count while the EDR boost converter has low device stress while achieving high gain. A novel Quadratic EDR (Q-EDR) boost converter is proposed which is capable of attaining ultra high gain at moderate levels of duty with low voltage and current stress across different devices. Two different configurations of the proposed topology are presented with the interleaved version being able to reduce the current ripple further and the converter can be extended to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$M$</tex-math></inline-formula> -phases in both the configurations. Detailed analysis of a 4-phase converter is presented along with converter design considerations. The performance of the proposed topology is validated through a 1 kW, 4-phase hardware prototype operating at 20 V-36 V input to 600 V output at 60 kHz. Experimental results corresponding to both interleaved and non-interleaved converter configurations are presented. Experimental results show that the converter can attain a conversion ratio of 30 at an operational duty close to 0.64 in the interleaved configuration. The switch voltage stress is limited to 150 V and quadratic stage diode voltage stress is limited to be less than 100 V for 600 V output condition enabling the use of low voltage devices. The converter is able to achieve a peak efficiency of 95.82% for 36 V to 600 V operation at 660 W.

A High Voltage Gain ZVT Quasi-Z-Source Converter With Reduced Voltage Stress

In this article, a new high voltage gain quasi-Z-source (QZS) dc–dc converter suitable for renewable energy applications is presented. The proposed converter utilizes a zero voltage transition auxiliary circuit with coupled inductors to provide soft-switching conditions for all switches for a wide range of output power. In addition, a switched capacitor circuit is employed to obtain a higher voltage gain and lower voltage stress. The main advantages of the proposed converter include high voltage gain, high efficiency, reduced switch and diode voltage stress, continuous input current, and common ground between the output and input, which are important features for photovoltaic applications. In this circuit, the reverse recovery problem of diodes is alleviated. Operating principles and design considerations of the proposed converter are analyzed. Moreover, to prove the validity of the theoretical analysis, a 200-W prototype of the proposed converter is implemented and the experimental results are shown.

A Single-Switch High-Voltage-Gain DC–DC Converter With Reduced Switch Voltage Stress

In this article, a novel single-switch high-voltage-gain dc–dc converter is presented. The proposed converter is operated with continuous input current, and the voltage stress across the power switch is lower compared to the competitive high-voltage-gain topologies. Hence, a lower rating active switch can be selected for the proposed configuration to achieve reduced conduction losses due to its low <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> -state resistance of the switch. The leakage energy of the coupled inductor is effectively recycled to the load through the voltage multiplier used in the topology. The voltage stress across the power diode at the output side is low, and hence, there is an improvement in the output-side reverse recovery performance. Moreover, the proposed topology has reduced aggregate diode voltage stress. A detailed comparative study consisting of steady-state analysis, working principle, and efficiency and reliability evaluation of the proposed converter for the continuous conduction mode is presented. The proposed concept is verified through extensive simulation studies and from the measured results from the experimental prototypes.

A new transformerless semi‐quadratic buck–boost converter based on combination of Cuk and traditional buck–boost converters

AbstractIn this paper, a new transformerless buck–boost converter is proposed. This converter is based on combining two basic converters, including Cuk and traditional buck–boost converters, along with a voltage multiplier (VM) at the output side. The proposed semi‐quadratic buck–boost converter operates in continuous conduction mode (CCM) and provides two operation modes by turning the switches on and off. This converter has some merits such as a wide conversion ratio and continuous input current. The proposed converter consists of two switches with simultaneous operation resulting in simplicity in control. A modular configuration and a wide range of duty cycles are available through the proposed converter, which causes higher or lower output voltage and facilitates the converter maintenance. The calculations of the ideal and the real voltage gain, voltage stress of switches and diodes, efficiency, and design consideration of elements are given in this paper. Finally, a prototype is implemented, and experimental waveforms are obtained to prove and validate the simulation results as well as the theoretical analysis of the proposed converter.

Effective Leakage Energy Recycling in High Gain DC-DC Converter With Coupled Inductor

A high voltage gain single switch DC-DC converter with efficient leakage energy recovery is presented in this brief. Effective leakage energy recycling is an important requirement in this class of converters with coupled inductors to overcome the high voltage stress across semiconductor devices. The proposed converter effectively recycles the leakage energy of the coupled inductor through a passive clamp circuit to the load. Hence, the efficiency of the converter is improved considerably. The proposed converter has the lowest switch voltage stress among other similar topologies, thereby making it feasible to select a low rating switch for the same boost gain. The converter has a lower sum of diode voltage stress and improved reverse recovery performance of the output side diode as well. The converter performance has been evaluated on the basis of different factors like efficiency, switch voltage stress, diode voltage stress, etc. The proposed converter performance is compared with that for various competitive topologies and is observed to be performing better. The effect of leakage inductance variation is studied on the gain of the converter. The proposed concept is verified via simulation and experimental prototype.

Design of a 3.3 kW/100 kHz EV Charger Based on Flyback Converter With Active Snubber

This article presents the feasibility of a flyback charger for electric vehicles (EV) based on silicon-carbide (SiC) devices. The flyback topology is simplest, but its device voltage stresses are strongly affected by the transformer leakage inductance. To reduce the device voltage stresses by recovering the energy stored in the transformer leakage inductance, an active-clamp circuit and active snubber circuit are adopted in both sides of the transformer. Also, the active-clamp circuit helps to reduce the switching losses by making zero-voltage-switching (ZVS) condition. By deriving the loss equations of switching devices and transformer as a function of the switching frequency and magnetic flux swing, design optimization considering loss and volume is attempted. The snubber capacity and diode voltage stress are quantitatively suggested through the analysis of the power absorbed by the active snubber. Based on the analysis, a 3.3 kW/100 kHz prototype is designed and experimented to show the feasibility. Test results demonstrate 96.7% peak efficiency and 96.4% full load efficiency at 330V output voltage.

Multilevel Step-Down Resonant Switched-Capacitor Converters With Full-Range Regulation

Multilevel resonant switched-capacitor converters (RSCCs) have drawn attention in large step-down voltage conversion but are hindered in a wide area of applications due to limited voltage regulation range. A new full-range regulation (FR) method for multilevel step-down RSCCs is proposed in this article. As an example of the proposed FR method, the fixed on-time modulation for modified Dickson RSCC is provided. In addition to full-range voltage regulation, the multilevel RSCCs with the proposed FR method feature complimentary driving signals, zero voltage switching turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> for switches, zero current switching turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> for diodes, even switch voltage stress, even diode voltage stress, high active switch utilization, high efficiency, and high power density. A modified Dickson RSCC prototype was built to validate the proposed FR method. The proposed FR method is further extended to series-parallel RSCCs and Fibonacci RSCCs.

An SVM Scheme for Three-Level Quasi-Switched Boost T-Type Inverter With Enhanced Voltage Gain and Capacitor Voltage Balance

This article introduces a space vector control method for the three-level quasi-switched boost T-type inverter, which provides some benefits such as: good output voltage quality, high voltage gain, and low voltage stress on power devices. By applying corresponding P-type or N-type small vectors in switching sequence, the neutral-point voltage unbalance problem can be solved easily. The advantage of this modulation solution is that it does not require any extra calculations. The upper-shoot-through and lower-shoot-through states are utilized instead of full-shoot-through, which is usually used in traditional single-stage three-level impedance source inverter, to ensure the boost capability of the inverter. These states are inserted into small vectors in order not to affect the output line-to-line voltage. Some investigations about voltage gain, diode, and switch voltage stress have been conducted to demonstrate the effectiveness of the proposed method. The experimental results are also presented to validate the accuracy of the proposed modulation method. The proposed approach has resulted in efficiency rise by 2% as compared to the conventional PWM scheme.

A New High Gain Active Switched Network-Based Boost Converter for DC Microgrid Application

This paper deals with an active switched inductor network-based high gain boost converter. By using less number of components in circuit topology, a higher gain in voltage can be attained at a small duty cycle value by using the proposed converter, which helps in reducing the switch voltage stress and conduction loss. In addition, it draws continuous input current, has lower diode voltage stress, and lower passive component voltage ratings. The operating principles and key waveforms in Continuous Conduction Mode (CCM) and Discontinuous Conduction Mode (DCM) are presented. Parameter design, power loss calculation, characteristics, and comparative study with other non-isolated converters have been presented. Finally, a 200W hardware prototype is constructed and the viability of the proposed converter is verified through the experimentally obtained results.

A ZVZCS Hybrid Dual Full-Bridge Converter Suitable for Wide Input Voltage Range

A phase-shift modulated converter with two full bridges at primary side and rectifier diodes in hybrid combination at secondary side is proposed in this article. Due to the proposed symmetrical modulation strategy, two full-bridges always equally share the total system power rating, and thus the VA rating of two transformers is minimized. The circulating currents decay to zero in the zero state, contributing to reduce the conduction loss and duty-cycle loss. Zero-voltage or zero-current switching is achieved for all switches over whole input voltage range with an auxiliary inductor. The rectifier output voltage is synthesized of two controlled transformer secondary voltages all the time, which achieves the same output current ripple suppression effect as the conventional input-parallel output-parallel full-bridge converters with interleaved control scheme, and reduces the voltage stress of rectifier diodes. These advantages make the converter suitable for wide input voltage range applications. In this article, the operation principle and steady-state analysis of the proposed converter are illustrated in detail. Experimental results with 220–460 V input voltage are demonstrated to verify the advantages.

A T‐type three‐level converter for wide‐range voltage application

AbstractFuel and solar cells are broadly used in Microgrids. However, their output varies widely when load and environment change extensively. Thus, DC‐DC converters are used for wide‐range voltage application. Nevertheless, output filter inductor is large and voltage stress of diodes is high in two‐level converters when input voltage varies widely. Therefore, a T‐type three‐level converter is proposed. A T‐type cell is added into the full‐bridge (FB) converter. The proposed converter can work in two‐ and three‐level modes, that is, 2L and 3L modes. It works in 2L mode in high input voltage. Thus, the output filter inductance and voltage stress of diodes in 2L mode decrease compared to the FB converter. Operating principle is illustrated. In addition, design guidelines and examples are shown. Finally, experimental results confirm the theoretical analysis.

Soft Switching Interleaved High Step-Up Converter With Multifunction Coupled Inductors

This article presents an efficient interleaved soft switching dc-dc converter for high step-up applications. In the proposed converter, two multifunction coupled inductors are employed to increase the voltage gain, accomplish soft switching operation for all semiconductors in a wide range of load variations, and smooth the input current. Besides, the leakage inductance energy is recovered to enhance the voltage gain and efficiency while assisting soft switching condition for the switches and diodes. In addition, no auxiliary switch or extra magnetic element is employed in the proposed converter while the voltage stress of switches and diodes is rather low. These have led to simple structure, high density, low cost, and improved efficiency. Theoretical analysis and design considerations for the proposed converter are presented. Moreover, the experimental results of a 48 to 500 V laboratory prototype approve the effectiveness of the proposed topology.

Switched‐coupled‐inductor Z‐source inverter with a high boost inversion capability

A novel converter with a three-winding coupled inductor, called switched-coupled-inductor Z-source inverter (SCI-ZSI), is developed based on the switched-and-coupled inductor technology in this study. Compared with the conventional switched-inductor Z-source inverter and trans-Z-source inverter, the novel inverter had a higher voltage-boosting capability. In addition, the improved topology shared a common ground point between the DC source and the inverter bridge. Under the same modulation index and load conditions, the input diode and capacitor voltage stress of the proposed inverter were lower than those of the other topologies. The operating principles, impedance-network design, voltage and current stress are presented. The theoretical findings were verified by simulation and experimental results.

Analysis and design of an isolated high step‐up converter based on the secondary side quasi‐resonant loops

In a high step-up converter, the primary side input current contributes a significant share of total power loss. Meanwhile, high-voltage stresses of secondary side components are also big issues. This study proposes an isolated converter with secondary side quasi-resonant loops. The push–pull structure is adopted to reduce active switch numbers so the primary side power loss can be controlled in a very minor range. The newly added resonant loops on the secondary side significantly decrease the current stresses of the resonant capacitors, so the power loss caused by capacitor equivalent-series-resistance is reduced. The voltage stresses of diodes and capacitors on the secondary side are also decreased by an improved symmetrical-voltage-quadrupler-rectifier structure. The proposed converter is with the maximum voltage gain equal to 4 without consideration of the transformer. Therefore, it is helpful to decrease the transformer turns ratio. The operation process is analysed in detail and the design considerations are also summarised. Theoretical analysis is verified by the experimental results of a 400 W prototype with 34–40 V input and 380 V output.

Hybrid Nonisolated Active Quasi-Switched DC-DC Converter for High Step-up Voltage Conversion Applications

This paper deals with a hybrid non-isolated active quasi-switched dc-dc converter with a high-boost voltage gain, which is applicable for the high step-up low power applications. By using fewer number of components in circuit topology, the proposed converter can provide higher-gain voltage with a small duty cycle, which can reduce the voltage stress and conduction loss on power switches. In addition, it draws continuous input current, has lower diode voltage stress and lower passive component voltage ratings. The operating principles and key waveforms in continuous conduction mode and discontinuous conduction mode are presented. Small-signal dynamic analysis, parameter design guideline, power loss calculation, and characteristics comparison with other non-isolated converters have been completed. Finally, a 250W hardware prototype is constructed and the experimental results are presented to verify the feasibility of the proposed converter.

A ZVS Three-Port DC/DC Converter for High-Voltage Bus-Based Photovoltaic Systems

In high-voltage bus-based photovoltaic systems, a power electronic interface is required to manage the power flow in between the photovoltaic (PV) panel, battery, and the high-voltage dc bus. In this paper, a novel three-port dc/dc topology is proposed for this application. Pulsewidth and phase-shift offer two degrees of freedom to effectively regulate the power flows. On the primary side, the input current ripple is reduced due to the interleaved structure. This avoids the usage of the bulky electrolytic capacitors on the PV terminal. On the secondary side, a voltage sixfolder rectifier is employed to boost the step-up ratio. This reduces the transformer's secondary-side turns number. Moreover, the voltage stresses of secondary-side mosfets and diodes are reduced to one-third of the output voltage. Zero-voltage switching and zero-current switching are realized among all power mosfets and diodes, respectively, and in an extended range. A 500-W converter prototype, linking a battery pack, a PV panel, and a 760 V dc bus, is designed and tested to verify the proof-of-concept. Both the circuit functionality and theoretical analysis are validated by the experimental results.

Quasi-Resonant Voltage Doubler With Snubber Capacitor for Boost Half-Bridge DC–DC Converter in Photovoltaic Micro-Inverter

This paper proposes a quasi-resonant boost half-bridge dc–dc converter with high power conversion efficiency and a wide input voltage range for a photovoltaic micro-inverter. The proposed converter has a combined structure of a boost-integrated half-bridge converter on the primary side of the transformer and a voltage doubler with a snubber capacitor on the secondary side. By using the quasi-resonance techniques, it achieves zero-voltage switching (ZVS) turn- on and low turn- off losses for the switches, as well as ZVS turn- on for the diodes. In addition, the proposed converter has no dc-magnetizing current for the transformer due to the dc-blocking capacitor, and it doubles the voltage gain with half the voltage stress of diodes through the voltage doubler. The effectiveness of the converter was verified with a 300-W prototype with an input voltage range of 13–50 V, an output voltage of 400 V, and a switching frequency of 50 kHz. The experimental results show that the converter had more than 90.0% power conversion efficiency for the output power range of ∼300 W, and its maximum power conversion efficiency was 97.5% for an output power of 160 W.