Leakage Inductance Energy Research Articles

Design, analysis, and implementation of a new high step‐up DC–DC converter with low input current ripple and ultra‐high‐voltage conversion ratio

In this study, the analysis and design of a coupled-inductor (CL)-based ultra-high step-up single-switch DC–DC converter are presented. With the aid of the CL and voltage multiplier cell, the suggested topology can obtain ultra-high-voltage gain without a large turn ratio and extreme duty cycle. A passive clamp circuit is utilised in the structure of the introduced converter for not only alleviating voltage spike on the main switch effectively but also recycle the leakage inductance energy. So low-voltage rating and low on-state resistance metal oxide semiconductor field-effect transistor is allowed to increase efficiency and lower the conduction losses. The input current ripple of the suggested topology is very low due to connecting an inductor to the suggested structure input section, which is very friendly and desirable to the photovoltaic and fuel cell applications. The suggested converter steady-state analysis, operation principle, theoretical efficiency analysis, and design procedure are described comprehensively in this study. Furthermore, the suggested converter superiority is illustrated over various alike recently introduced the most important DC–DC structures in the comparison study. Finally, a laboratory prototype is fabricated with a 225 W output power to confirm the theoretical analysis of the introduced converter.

Bidirectional Soft-Switching Converter With Reduced Current Ripple at Low-Voltage Side

Bidirectional dc–dc converters with storage devices and high-voltage conversion ratio are widely utilized in renewable energy systems in order to manage power flow between renewable sources, storage devices, and load. One of the most important parameters in these converters, which affects the lifetime of storage devices, is the pulsating current flowing through them. This article presents a bidirectional buck/boost converter that employs a coupled inductors technique to increase the voltage conversion ratio while the current in low-side voltage source is continuous. Furthermore, only an active clamp circuit, including a clamp capacitor and an auxiliary active switch, is utilized to create soft-switching conditions for the main switches and absorb the leakage inductance energy of coupled inductors for both high step-up/step-down operating states. In this converter, the soft-switching condition is provided for all switches without any extra element in the power flow direction. Also, all diodes turn off at the ZCS condition, which removes the reverse recovery problem. A low number of elements and fully soft-switching condition for all semiconductor devices have contributed to the converter efficiency. Theoretical analysis of the proposed converter in both operating states is presented in detail, and a 500-W prototype circuit is implemented to verify the validity of the theoretical analysis and converter performance.

A Dynamic Resonant Period Control Technique for Fast and Zero Voltage Switching in GaN-Based Active Clamp Flyback Converters

Compared to Si FETs, when the main GaN FET is in full zero voltage switching condition, maximum switching loss reduction can be achieved. Therefore, in this article, an active clamp flyback converter with GaN devices that implements fast ZVS by using the proposed dynamic resonant period control (DRPC) technique can reduce large transformer leakage inductance energy loss on the active resonant circuit. As the loading changes, the DRPC technique can dynamically adjust the on -time in auxiliary switch to prevent large voltage stress on the components in the primary side. In full load condition, the leakage energy loss can be reduced, thereby transferring more energy to the secondary side with maximum efficiency up to 94%.

A New Nonisolated High-Step-Up DC–DC Converter Topology with High Voltage Gain Using Voltage Multiplier Cell Circuit for Solar Photovoltaic System Applications

The solar photovoltaic (PV) source is preferred to be functioned at low voltages. The practical systems such as grid-tied systems require a high output voltage causing a reduction in conversion efficiency. To handle this problem, this paper presents a new nonisolated boost DC–DC converter with a single switch suitable for solar PV applications. This converter comprises dual voltage multiplier (VM) cells, leakage energy recovery scheme, and coupled inductor (CI) techniques to get the desired output voltage from the converter. The double-clamp capacitors are connected to the primary side of the CI. The clamp capacitors can share the current through CI, and it ensures that the leakage inductance energy of CI can be recovered, leading to an expansion in the converter voltage gain and conversion efficiency. In addition, the clamp circuit clamps the voltage stress of the MOSFET switch, and the clamp capacitors will discharge at a specific time to increase the converter gain. A high duty cycle is not necessary for getting a high voltage gain, which avoids the diode reverse recovery issues. The converter can be operated in both continuous conduction mode (CCM) and discontinuous conduction mode (DCM). A 500-W experimental prototype is developed for experimental validation, and the supporting simulation results are presented. The maximum efficiency of the converter is 93.94%, and, at full load, the efficiency is 92.55%.

A High-Gain Interleaved DC–DC Converter with Passive Clamp Circuit and Low Current Ripple

In this paper, a novel non-isolated interleaved DC/DC boost converter is presented in which coupled inductors and a passive clamp circuit are employed. ZCS turn-on condition for main switches is provided, and the stored energy in leakage inductance is recycled by means of a passive clamp circuit. Therefore, the voltage stress across switches is reduced resulting in circuit efficiency improvement. Due to interleaved structure and cross-coupled inductors, the input current ripple is reduced and the input current is continuous. To achieve ZCS turn-on condition, the intrinsic leakage inductance of the coupled inductors is used which leads to improving the power density and reducing the switching losses. In order to confirm the theoretical analysis, a prototype with 30 V input voltage, 300 V output voltage, and 300 W is implemented and tested.

Novel high gain DC–DC converter based on coupled inductor and diode capacitor techniques with leakage inductance effects

In this study, due to the low output voltage that often is presented by renewable energy sources like photovoltaic panels, a single switch high step-up dc–dc converter with high efficiency is proposed. The presented step-up dc–dc converter uses a coupled inductor and diode-capacitor technique to achieve high voltage gain. By changing the turns ratio of the coupled inductor, this novel topology does not need to operate at a high duty cycle conditions to obtain the high voltage gain. Moreover, the leakage inductance energy of the coupled inductor is recovered by using two passive clamp circuits to reduce the stress across the semiconductor devices, which improve efficiency. The operating modes of the proposed converter and the theoretical analysis are considered and finally, a prototype setup has been implemented to accredit the accuracy of the theoretical and simulation analysis.

Interleaved High Step-Up DC–DC Converter with Voltage-Lift and Voltage-Stack Techniques for Photovoltaic Systems

A novel interleaved high step-up DC–DC converter applied for applications in photovoltaic systems is proposed in this paper. The proposed configuration is composed of three-winding coupled inductors, voltage multiplier cells and a clamp circuit. The step-up voltage gain is effectively increased, owing to the voltage-stack and voltage-lift techniques using the voltage multiplier cells. The leakage inductor energy is recycled by the clamp circuit to avoid the voltage surge on a power switch. The low-voltage-rated power switches with low on-state resistances and costs can be used to decrease the conduction losses and increase the conversion efficiency when the voltage stresses of power switches for the converter are considerably lower than the high output voltage. The reverse-recovery problems of diodes are mitigated by the leakage inductances of the coupled inductors. Moreover, both the input current ripple and the current stress on each power switch are reduced, owing to the interleaved operation. The operating principle and steady-state analysis of the proposed converter are thoroughly presented herein. A controller network is designed to diminish the effect of the variations of input voltage and output load on the output voltage. Finally, the experimental results for a 1 kW prototype with 28–380 V voltage conversion are shown to demonstrate its effectiveness and performance.

Capacitor Charging by Quasi-Resonant Approach for a Pulsed Plasma Thruster in Nano-Satellite

In this article, a quasi-resonant (QR) flyback converter has been proposed for capacitor charging in a pulsed plasma thruster (PPT) of a nano-satellite. The energy in the transformer leakage inductance can be recycled to the resonant capacitor, suppressing the switch-off voltage spikes on the semiconductor power switch. The power switch is turned on with a hybrid switching mode. In this mode, valley-voltage-switching (VVS) is applied until the zero-voltage stress on the power switch is obtained, and zero-voltage-switching (ZVS) is used in the remaining charging process. Consequently, the switching-on loss is reduced, and charging efficiency is improved. When a capacitor bank of $2\mu \text{F}$ is charged to 1.5 kV (i.e., 2.25 J), the switching loss contribution of QR flyback converter using hybrid switching approach is reduced significantly to 0.61% while a flyback converter using hard-switching technique has a switching loss contribution of 15.24%. As a result, the proposed QR flyback converter improves the charging efficiency by 2.43%, from 72.69% to 75.12%. Moreover, the diode in the secondary side can be turned-on with zero-voltage and off with zero-current. Hence, the turn-on overshoot voltage and recovery loss are reduced.

Novel Three-Port Bidirectional DC/DC Converter with Three-Winding Coupled Inductor for Photovoltaic System

This study proposes a novel three-port bidirectional converter with a three-winding coupled inductor and applies it to a photovoltaic (PV) system to step up the PV system output to a dc bus or dc load while charging the battery. When the PV output is insufficient, battery voltage is stepped up to the dc bus voltage, and when the dc bus has excess energy, it is stepped down to charge the battery. Thus, a three-port bidirectional high step-up/step-down converter is achieved. A three-winding common core coupled inductor is designed and implemented in the converter, and a full-wave doubler circuit is used on the high-voltage side to achieve a high step-up effect. Power switches and diodes in the circuit are shared to achieve bidirectional operation. The output capacitors recover secondary-side leakage inductance energy in the step-up mode, and the third winding can be used to recover primary-side leakage inductance energy to reduce the voltage spike on switching in order to improve the converter’s conversion efficiency. A 500-W three-port bidirectional converter is implemented to verify the feasibility and practicability of the proposed topology. According to the measurement results, the highest efficiency of the PV step-up mode is 95.3%, the highest efficiency of the battery step-up mode is 94.1%, and the highest efficiency of the step-down mode is 94.8%.

A Hybrid Cascaded High Step-Up DC–DC Converter With Ultralow Voltage Stress

A novel hybrid cascaded dc–dc converter is proposed for high voltage gain applications in this article, which is characterized by the hybrid series-parallel connection based on coupled inductors and voltage multiplier cells. The input current ripple is decreased due to the interleaved operation and the voltage stress of the switches is only 1/6 of the output voltage when the turn ratio is 1. So the high-performance MOSFETs with low ON-state resistance can be used to reduce the conduction losses. The reverse-recovery problem of the output diode can be suppressed by the leakage inductance of the coupled inductors. The leakage inductance energy of the coupled inductors is absorbed and recycled to the output, which can largely improve the efficiency of the proposed converter. The working principle and steady-state characteristics of the converter are analyzed in detail. Finally, the correctness of the theoretical analysis is verified through experimental results of a 400-W laboratory prototype.

Bipolar Phase Shift Modulation Single-Stage Audio Amplifier Employing a Full Bridge Active Clamp for High Efficiency Low Distortion

Two-stage power conversion of class-D amplifier with front-end switching mode power supply affects the power conversion efficiency of audio amplifier system. Single-stage inverter (SSI) developed from cycloconverter can be used as audio amplifier to improve efficiency. However, current commutation of cycloconverter switches challenges for high efficiency and low total harmonic distortion (THD). In this article, a bipolar phase shift modulation (BPSM) SSI is proposed for high efficiency low distortion audio amplification. Full bridge active clamp (FBAC) circuit is used to clamp the voltage across cycloconverter switches and recycle the energy of filter inductor and leakage inductance. By using active clamp, utilization of magnetizing inductance current and optimization of driving sequence of clamp switches, zero voltage switching of the proposed BPSM FBAC-SSI is achieved over wide range. With BPSM and voltage clamp across cycloconverter switches, low THD of output voltage is also achieved. A 200 kHz prototype with 250 W output power is presented to verify the analysis results of the proposed BPSM FBAC-SSI.

High Step-Up Interleaved Converter Mixed With Magnetic Coupling and Voltage Lift

In this paper, a non-isolated high step-up interleaved DC-DC converter for distributed generation applications such as solar cells and fuel cells. The proposed converter mixes the benefits of magnetic coupling, voltage multiplier, and voltage lift techniques to conventional interleaved schemes. The proposed converter's voltage lift technique can increase the voltage gain while guaranteeing low voltage stress of the switches. And the magnetic coupling method can combine the switched capacitor of the voltage multiplier technique with the lossless clamp circuit to achieve high voltage gain and reuse the leakage inductance energy to the output terminal. In addition, this leakage inductance energy can achieve zero current switching turn on soft switching performance and mitigate the output diode reverse recovery problem. The proposed converter avoids the extreme duty cycles that cause conduction losses in power devices and can give very low voltage stresses. Therefore, the use of low voltage rated MOSFETs and diodes not only reduces switching losses and costs, but also improves efficiency.

Two‐ and three‐winding coupled‐inductor‐based high step‐up DC–DC converters for sustainable energy applications

This study proposes two configurations for a non-isolated, high step-up, single-switch, coupled-inductor-based DC–DC converter. A coupled inductor and voltage multiplier cells are used in the presented topologies to obtain a high voltage gain. Also, a passive clamp circuit is applied in the topologies to reduce voltage stress of the main power switch. This leads to utilising a power switch with lower on-state resistance, which decreases the conduction loss. Several advantages such as low operating duty cycle, high voltage conversion ratio, reduced voltage stress of semiconductors, low turn ratio of the coupled inductor, leakage inductance energy recovery and high efficiency operation make the presented structures appropriate for sustainable energy applications. The operational principle and steady-state analysis of the suggested topologies in continuous conduction mode are expressed in detail. Also, design procedure and theoretical efficiency of the topologies are presented. Then, the suggested topologies are compared with several similar high step-up topologies to prove their advantages. Finally, the performance and feasibility of the proposed DC–DC converter configurations are confirmed through experimental measurement results of 29 V input and 435 V/213 W and 480 V/238 W output laboratory prototypes at 50 kHz switching frequency.

A High Step-Down Buck Converter With Self-Driven Synchronous Rectifier

In this article, a new single-switch buck converter (without considering the synchronous rectifier) with extended duty cycle and continuous output current is proposed. The presented converter employs a self-driven synchronous rectifier with gate energy recovery, which leads to efficiency improvement and simplicity of the converter and the gate drive circuit. The extended duty cycle results in lower current stress of the high-side MOSFET and reduced voltage stress across the synchronous rectifier. Furthermore, the reverse recovery losses of synchronous rectifier are dramatically decreased due to the applied coupled inductors. The introduced converter also provides shoot-through protection and load protection when the high-side MOSFET remains on . In order to clamp the drain–source voltage spikes of the main switch and recover the leakage inductance energy, a lossless snubber circuit is added, which reduces the turn- off drain–source voltage and consequently decreases the turn- off switching losses of the main MOSFET . Moreover, the main switch turns on under zero current switching (ZCS), which results in efficiency improvement. A 150-W prototype of the proposed converter is implemented to verify the theoretical analysis and confirm its efficiency improvement and advantages.

Coupled Inductor-Based High Voltage Gain DC–DC Converter For Renewable Energy Applications

In this article, a novel coupled inductor-based high step-up dc–dc converter is proposed. The introduced converter benefits from various advantages, namely ultrahigh voltage gain, low voltage stress on the power switches, and continuous input current with low ripple. Therefore, the presented converter is suitable for renewable energy applications. By utilizing clamped circuit, voltage spike of the active switch is clamped during the turn- off process. Hence, a switch with low $R_{\text{DS-on}}$ can be used, which reduces the conduction losses as well as the cost of the converter. Furthermore, the energy of leakage inductance is used to obtain zero voltage switching (ZVS) for the main and auxiliary switches. Additionally, the output diode current falling rate is controlled by leakage inductance; thus, reverse-recovery problem of output diode is alleviated. The steady-state analysis and design considerations of the proposed converter are discussed. Finally, a 250-W experimental prototype of the presented converter is implemented to validate the converter operation and the theoretical analysis.

A Three-Phase Single-Stage Isolated Flyback-Based PFC Converter With Leakage Energy Recovery Clamping Circuit

This article presents a three-phase single-stage isolated flyback-based power factor correction (PFC) converter with a clamping circuit to recover the transformer leakage inductance energy for more electric aircraft application. With the proposed clamping circuit, the transformers' leakage inductance energy is successfully captured in clamping capacitor, and subsequently, a constant power 28-V secondary supply is derived by using a two-switch forward converter to improve the converter overall efficiency. The converter unity power factor (UPF) operation is obtained by using the inherent resistance property of discontinuous conduction mode (DCM). Hence, the input current shaping circuit is eliminated and resulted in a single-loop control system. Thus, the converter control circuit requires only one sensor, which decreases the system cost and increases the system reliability and robustness. In addition, the converter provides fault-tolerant operation for single-phase loss. The converter is analyzed and the design equations are explained in detail. The voltage and current stress equations for all power components are derived and validated with the simulation. The novelty and the operation of the converter are demonstrated with the experimental results from a 2-kW laboratory prototype.

Dual-Input Isolated Converter With Dual-Charge-Pump Cell for High Step-Up Voltage Ratio Achievement

In this article, a novel dual-input isolated converter (DI2C) is proposed, which can process two different kinds of clean energy and possesses the features of galvanic isolation and high voltage gain. A dual-charge-pump cell is also proposed in this article and then immersed into the power stage to achieve a high step-up voltage ratio and recycle the energy of leakage inductance. Based on the configuration of the DI2C, even if either of the input sources is interrupted, the converter still can function and keep the high step-up feature. The DI2C only requires two active switches and two coupled inductors. Therefore, the power stage is concise, avoiding complicated control design and simplifying driver mechanism as well. The operation principle, theoretical analysis, and mathematical derivation are thoroughly described. A 200-W prototype is built and then tested to corroborate the correctness of the theoretical analysis and the feasibility of the proposed converter. The measured efficiency is 92.4% at full load.

Design a Single Stage AC to DC Converter for LED Driver With Power Factor Improvement

This paper shows the design of a single switch LED driver circuit which is based on the operation of boost converter and flyback converter with power factor correction. In the proposed driver circuit, the boost converter is made to operate in DCM mode for achieving a high power factor and the flyback converter is used for isolating the input-output in order to provide safety. In addition to this, a snubber circuit is also designed for clamping the peak voltage of the main switch into low voltage and also to recycle the leakage inductor energy. A capacitor of low-voltage rating is made to function as the DC bus capacitor due to reason that some amount of the input power is conducted directly towards the output side; the amount of power remaining is then stored in the DC bus capacitor. In this way, the proposed LED driver circuit provides a power factor of greater value, i.e., above 0.95 PF and also a high value of power conversion efficiency, i.e., above 90%.

High-Step-Down DC–DC Converter With Continuous Output Current Using Coupled-Inductors

This paper proposes a high-step-down dc–dc converter with continuous output current which utilizes coupled-inductors. Another main feature of this converter is applying the same number of switches as the synchronous buck converter. The introduced converter is suitable for non-isolated low-voltage high-current applications, especially voltage regulator modules (VRMs) with 12-V-input. Owing to extension of the duty cycle, the main mosfet current stress and the synchronous rectifier switch voltage stress are significantly reduced. However, the discharge of the leakage inductance energy increases the main mosfet voltage stress. By employing a simple lossless clamp/snubber circuit the leakage inductance energy is recovered, the voltage spike across the main mosfet is clamped, and the turn- off switching losses are reduced. There is at least one inductor in all current paths which creates an intrinsic protection against current shoot-through and provides zero-current-switching (ZCS) turn- on for the main mosfet. High efficiency is attained by the proposed converter due to extended duty cycle, low number of switches, and soft switching operation while the converter driver is just like the conventional buck converter. Due to the single-phase structure of the proposed converter, this converter is a viable alternative to the buck VRM. Similar to the other converters using coupled-inductors, the complexity of coupled-inductors design and the space occupied by coupled-inductors can be considered as drawbacks. A prototype of the proposed converter is implemented to verify the converter operation and the theoretical analysis.

Improvement in Voltage Conversion Ratio of Ultrahigh Step-Down Converter

A modified step-down converter is presented herein, which is mainly based on one coupled inductor and several energy-transferring capacitors to improve the voltage conversion ratio as well as to reduce the switch voltage stress. In addition, the portion of the leakage inductance energy can be recycled to the input via the active clamp circuit during the turn-off period and the switches have zero-voltage switching (ZVS) during the turn-on transient. In this paper, the basic operating principles of the proposed converter are firstly described and analyzed, and its effectiveness is finally demonstrated by experiment based on a prototype with input voltage of 60 V, output voltage of 3.3 V and rated output power of 33 W.