Ripple-free Input Research Articles

A Ripple-free Input Current Interleaved Converter with Dual Coupled Inductors for High Step-up Applications

A Ripple-free Input Current Interleaved Converter with Dual Coupled Inductors for High Step-up Applications

Interleaved High Step-up DC-DC Converter with Diode-Capacitor Multiplier Cell and Ripple-Free Input Current

Interleaved High Step-up DC-DC Converter with Diode-Capacitor Multiplier Cell and Ripple-Free Input Current

Interleaved High Step-up DC-DC Converter with Diode-Capacitor Multiplier Cell and Ripple-Free Input Current

In this paper interleaving and switched-capacitor techniques are used to introduce a high step-up DC-DC converter for renewable energy systems application. The proposed converter delivers high voltage gain without utilizing transformer or excessive duty cycle and features ripple-free input current which results in lower conduction losses and decreased electromagnetic interference (EMI). Lower output capacitance is another advantage of proposed converter, leading to smaller size and lower cost. Furthermore lower voltage stress on switches allows the utilization of switches with low resistance. Simulation results verify the performance of suggested converter.

Interleaved High Step-up DC-DC Converter with Diode-Capacitor Multiplier Cell and Ripple-Free Input Current

In this paper interleaving and switched-capacitor techniques are used to introduce a high step-up DC-DC converter for renewable energy systems application. The proposed converter delivers high voltage gain without utilizing transformer or excessive duty cycle and features ripple-free input current which results in lower conduction losses and decreased electromagnetic interference (EMI). Lower output capacitance is another advantage of proposed converter, leading to smaller size and lower cost. Furthermore lower voltage stress on switches allows the utilization of switches with low resistance. Simulation results verify the performance of suggested converter.

A Modified Bridgeless Converter for SRM Drive with Reduced Ripple Current

<p>Single Phase Switched Reluctance Motor is more popular in many industrial purposes for high speed applications because of its robust and rugged construction. For low cost and variable speed drive applications SRM are widely used.Due to doubly salient structure of motor, the torque pulsations are high when compared to other sinusoidal machines. The major drawback in using SRM drive is torque pulsations and increased number of switching components. In order to overcome these drawbacks, a bridgeless Single Ended Primary Inductor Converter (SEPIC) is proposed. The major advantages of this converter are continuous output current,smaller voltage ripple and reduced semiconductor current stress when compared to the conventional SEPIC converter. The ripple free input current is obtained by using additional winding of input inductor and auxiliary capacitors. To achieve high efficiency, active power factor correction circuits (PFC) are employed to precise the power factor. Further, the unity power factor can be obtained by making the input current during switching period proportional to the input voltage is proposed. The proposed system consists of reduced components and it is also capable of reducing the conduction losses. The working principles and the waveforms of proposed converter are analyzed. To analyze the circuit operation, theoretical analysis and simulation results are provided. Finally, the comparison between the waveforms of conventional SEPIC and proposed system is presented by using MATLAB/Simulink tools.</p>

Coupled‐inductor boost integrated flyback converter with high‐voltage gain and ripple‐free input current

DC–DC converters with high-voltage gain and low-input current ripple have attracted much attention in photovoltaic, fuel cells and other renewable energy system applications. Conventional boost–flyback converter can achieve high-voltage set-up ratio; however, its input current is pulsing and the voltage stress across output diode of flyback-cell is high. In this study, by incorporating coupled-inductor into the boost-cell of boost–flyback converter, the voltage stress across the output diode is effectively reduced. Passive snubber circuit is utilised to suppress the voltage spike across power switch, low-voltage-rated metal–oxide semiconductor field effect transistor (MOSFET) with low R ds_on can thus be used to reduce the conduction loss of power MOSFET. In addition, ripple-free input current can be achieved, which makes the design of electromagnetic interference filter easy. Steady-state characteristics of the proposed converter are analysed, and experimental results are given to verify the analysis results.

Interleaved High Step-up DC-DC Converter with Diode-Capacitor Multiplier Cell and Ripple-Free Input Current

Interleaved High Step-up DC-DC Converter with Diode-Capacitor Multiplier Cell and Ripple-Free Input Current

An Electrolytic-Capacitor-Free Single-Phase High-Power Fuel Cell Converter With Direct Double-Frequency Ripple Current Control

This paper proposes a direct double-frequency ripple current control in a single-phase high-power fuel cell converter that can achieve low-frequency ripple-free input current without using large electrolytic capacitors. To eliminate the double-frequency ripple current disturbance introduced by the single-phase inverter load, a proportional-resonant controller is developed to achieve an extra high control gain at designed resonant frequency. This high gain can be viewed as the virtual high impedance for blocking the double-frequency ripple energy propagation from inverter load to fuel cell stack. More particularly, the proposed control system can realize the utilization of all capacitive ripple energy sources in the system by regulating all the capacitors to have large voltage swing. In addition, this voltage swing is synchronized to keep real-time balancing of the transformer primary- and secondary-side voltages. As a result, the zero-voltage-switching operation for all switching devices in the dc-dc stage can be guaranteed. The controller design guidelines are derived based on the system small-signal model. The experimental results are presented to validate the theoretical analysis and proposed technology.

High step‐up DC–DC converter with ripple free input current and soft switching

Fuel cells are used as a power generator in distributed generation and aircrafts applications. This paper proposes a new high step-up DC–DC converter with zero-voltage switching (ZVS) of switches and zero current switching (ZCS) of diodes, to be used as fuel cell's power conditioner. To have a ripple free input current, a coupled inductor can be used at the input side of the converter. The voltage gain of the converter is calculated and required conditions for soft switching have been presented. The voltage stress of elements of the proposed converter is discussed, the efficiency of converter is derived and finally experimental results have been used to validate the properties of the converter.

Design of Soft Switching Sepic Converter Fed DC Drive Applications

High efficiency DC-DC converters with high-voltage gain have been researched due to increasing demands. A softswitching single-ended primary inductor converter (SEPIC) is presented in this work. An auxiliary switch and a clamp capacitor are presented in this project. A coupled inductor and an auxiliary inductor are utilized to obtain ripple-free input current and achieve zero voltage-switching (ZVS) operation of the main and auxiliary switches. The voltage multiplier technique and active clamp technique are applied to the conventional SEPIC converter to increase the voltage gain, reduce the voltage stresses of the power switches and diode. Moreover, by utilizing the resonance between the resonant inductor and the capacitor in the voltage multiplier circuit, the zero-current-switching (ZVS) operation of the output diode is achieved and its reverse-recovery loss is significantly reduced. The converter achieves high efficiency due to soft switching commutation of the power semiconductor device. The circuit is simulated using MATLAB Simulink and output result is verified.

High boost ratio DC–DC converter with ripple‐free input current

A high boost ratio non-isolated converter with a ripple-free input current is proposed, which combines a zero-ripple boost cell and a coupled inductor to achieve a high output voltage step-up. A passive snubber is utilised to suppress voltage spike of the switch caused by the resonance of the leakage inductance of the coupled inductor and the parasitic capacitance of the switch. Therefore, a low-voltage-rated metal oxide semiconductor field effect transistor (MOSFET) with low rDS(ON) can be used to improve the efficiency of the converter. In addition, a ripple-free input current can be achieved, making the electromagnetic interference (EMI) filter simple. Experimental results of a 100 W (40 V/200 V) prototype are presented to verify the analysis results of the proposed converter.

A Fuel Cell Power Conditioning System With Low-Frequency Ripple-Free Input Current Using a Control-Oriented Power Pulsation Decoupling Strategy

This paper proposes a fuel cell power conditioning system based on the current-fed dual-half-bridge (CF-DHB) dc-dc converter that can achieve low-frequency ripple-free input current using a control-oriented power pulsation decoupling strategy when an inverter load is connected to the fuel cell system. Without adding any extra circuit components, the proposed power pulsation decoupling strategy can realize a smaller dc bus capacitor; a film capacitor, therefore, can be applied in this fuel cell power conditioning system to replace the bulky electrolytic capacitor. In order to eliminate the double-frequency ripple current disturbance introduced by the inverter load to the fuel cell stack, a proportional-resonant controller is developed to achieve an extra high control gain at a designed resonant frequency. The operation principles of the CF-DHB converter with a proposed power pulsation decoupling strategy are analyzed. In addition, the controller design guidelines are derived based on the system small-signal model. The experimental results of a 1-kW fuel cell power conditioning system are presented to validate the proposed technology.

Bridgeless SEPIC Converter With a Ripple-Free Input Current

Conventional power factor correction (PFC) single-ended primary inductor converter (SEPIC) suffers from high conduction loss at the input bridge diode. To solve this problem, a bridgeless SEPIC converter with ripple-free input current is proposed. In the proposed converter, the input bridge diode is removed and the conduction loss is reduced. In addition, the input current ripple is significantly reduced by utilizing an additional winding of the input inductor and an auxiliary capacitor. Similar to the conventional PFC SEPIC converter, the input current in a switching period is proportional to the input voltage and near unity power is achieved. The operational principles, steady-state analysis, and design equations of the proposed converter are described in detail. Experimental results from a 130 W prototype at a constant switching frequency of 100 kHz are presented to verify the performance of the proposed converter.

Single-stage electronic ballast with high-power factor

This article proposes a single-stage electronic ballast circuit with high-power factor. The proposed circuit was derived by sharing the switches of the power factor correction (PFC) and the half-bridge LCC resonant inverter. This integration of switches forms the proposed single-stage electronic ballast, which provides an almost unity power factor and a ripple-free input current by using a coupled inductor without increasing the voltage stress. In addition, it realises zero-voltage-switching (ZVS) by employing the self-oscillation technique. The saturable transformer constituting the self-oscillating drive limits the lamp current and dominates the switching frequency of the ballast. Therefore, the proposed single-stage ballast has the advantage of high-power factor, high efficiency, low cost and high reliability. Steady-state analysis of the PFC and the half-bridge LCC resonant inverter are described. The results of experiments performed using a 30 W fluorescent lamp are also presented to confirm the performance of the proposed ballast.

Soft-Switching SEPIC Converter With Ripple-Free Input Current

A soft-switching single-ended primary inductor converter (SEPIC) is presented in this paper. An auxiliary switch and a clamp capacitor are connected. A coupled inductor and an auxiliary inductor are utilized to obtain ripple-free input current and achieve zero-voltage-switching (ZVS) operation of the main and auxiliary switches. The voltage multiplier technique and active clamp technique are applied to the conventional SEPIC converter to increase the voltage gain, reduce the voltage stresses of the power switches and diode. Moreover, by utilizing the resonance between the resonant inductor and the capacitor in the voltage multiplier circuit, the zero-current-switching operation of the output diode is achieved and its reverse-recovery loss is significantly reduced. The proposed converter achieves high efficiency due to soft-switching commutations of the power semiconductor devices. The presented theoretical analysis is verified by a prototype of 100 kHz and 80 W converter. Also, the measured efficiency of the proposed converter has reached a value of 94.8% at the maximum output power.

Improved ZVS DC-DC Converter With a High Voltage Gain and a Ripple-Free Input Current

An improved zero-voltage-switching (ZVS) dc-dc converter with a high voltage gain and a ripple-free input current is proposed. It consists of two converter cells - a boost cell and an asymmetrical pulse-width-modulation (APWM) full-bridge cell. The boost cell in the proposed converter has the capabilities of providing a ripple-free input current. The APWM full-bridge cell provides a high voltage gain. The output diodes are under zero-current-switching (ZCS) during turn-off. The proposed converter has high efficiency due to soft-switching operation in full-bridge switches. Steady-state analysis of the converter is presented to determine the circuit parameters. A laboratory prototype of the proposed converter is developed, and its experimental results are presented for validation.

High-Power-Factor Single-Stage LCC Resonant Inverter for Liquid Crystal Display Backlight

The aim of this paper is to propose a high-power-factor (HPF) single-stage inductor-capacitor-capacitor (LCC) resonant inverter for liquid crystal display (LCD) backlight. A half-bridge LCC resonant inverter shares switches with a power-factor-correction circuit to form single stage. The proposed single-stage LCC resonant inverter can achieve almost unity power factor and ripple-free input current by using a coupled inductor, and can also realize zero-voltage-switching by operating the switches above the resonant frequency. Thus, the proposed single-stage inverter not only provides HPF to the utility line, but also achieves circuit simplicity, low cost, and high reliability. Experimental results on a 32-in LCD backlight are obtained to show the performance of the proposed inverter.

Analysis and performance of novel and highly efficient electronic ballast operating at unity-power-factor

This paper presents the electronic ballast, in which the coupling inductors are used to inject the current to the dc-bus capacitors, to boost the dc-bus voltage and to filter out the ripples from input line current. The current injection coupling inductor injects its stored energy to the dc-bus capacitors in every switching half cycle. Whereas, the boost coupling inductor keeps the dc-bus voltage always above the peak of ac input voltage. Therefore, the proposed ballast maintains unity-power-factor and high efficiency with ripple-free input current over wide range of input line voltage in case of worst regulation. A symmetrical half-bridge inverter is used to drive the fluorescent lamps. The experimental results of the laboratory prototype ballast for 2 × 36 W fluorescent lamps operating at 50 kHz are presented.

Single-Stage Autotransformer-Based VRM With Input Current Shaper

This paper presents a novel single-stage autotransformer-based voltage regulator module (VRM) with input current shaper. The proposed VRMs with autotransformer achieve possible reductions in switch rms current ratings and filter capacitance. This in turn leads to an increase in power density. The proposed topology can extend the converter duty cycle greater than 50% which the transient performance and overall efficiency may benefit from this. Most of the researched ripple reduction methods cascade a boost-type converter with the VRM system. It is found that the push pull converter, when the duty cycles of the switches are greater than 50%, can simplify the front end of the boost-type converter to a novel single-stage VRM. In order to reduce the VRM size and weight and to achieve near ripple-free input current, coupled inductor techniques are used in the proposed VRM. A prototype is built to illustrate the theoretical prediction.

Single-stage resonant converter with power factor correction

A novel single-stage resonant converter with power factor correction is presented. Most of the researched power factor corrected rectifiers cascade a boost-type converter with the system. It is found that the half-bridge resonant converter, when the duty cycles are greater than 50%, can simplify the front end of the boost-type converter to a novel single-stage converter. To reduce the converter size and weight and to achieve ripple-free input current, coupled inductor techniques are used in the proposed converter. The operation principle and system steady analysis of the adopted converter are discussed in detail. A prototype has been built to demonstrate the system performance.