ANovel Non-Isolated Cubic DC-DC Converter with High Voltage Gain for Renewable Energy Power Generation System

In recent years,switched inductor(SL)technology,switched capacitor(SC)technology,and switched inductor-capacitor(SL-SC)technology have been widely applied to optimize and improve DC-DC boost converters,which can effectively enhance voltage gain and reduce device stress.To address the issue of low output voltage in current renewable energy power generation systems,this study proposes a novel non-isolated cubic high-gain DC-DC converter based on the traditional quadratic DC-DC boost converter by incorporating a SC and a SL-SC unit.Firstly,the proposed converter’s details are elaborated,including its topology structure,operating mode,voltage gain,device stress,and power loss.Subsequently,a comparative analysis is conducted on the voltage gain and device stress between the proposed converter and other high-gain converters.Then,a closed-loop simulation system is constructed to obtain simulation waveforms of various devices and explore the dynamic performance.Finally,an experimental prototype is built,experimental waveforms are obtained,and the experimental dynamic performance and conversion efficiency are analyzed.The theoretical analysis’s correctness is verified through simulation and experimental results.The proposed converter has advantages such as high voltage gain,low device stress,high conversion efficiency,simple control,and wide input voltage range,achieving a good balance between voltage gain,device stress,and power loss.The proposed converter is well-suited for renewable energy systems and holds theoretical significance and practical value in renewable energy applications.It provides an effective solution to the issue of low output voltage in renewable energy power generation systems.

Experimental Study of a Quadratic Boost: The Cascaded Connected Single Switch

The quadratic boost is studied under its real model. The equations, of the continuous conduction mode, descriptive of this model are established. From these equations, the expressions of the voltage gain and the efficiency are extracted. These two quantities are plotted as a function of the duty cycle in order to appreciate them in different operating points of the transistor. The values of the different components have also been extracted for the fabrication of a prototype of the converter. Thanks to a set of experimental measurements at the input as well as at the output of the prototype converter, the voltage gain and the efficiency could also be observed. These were also plotted for different loads to observe converter behavior. The theoretical curves were compared with the experimental curves which allowed to validate the proposed mathematical models on a large range of duty cycles.

An Improved Y-source Inverter with the Capability of Absorbing Bus Voltage Spike

In order to avoid the bus voltage spikes caused by leakage inductance endangering the normal operation of the inverter,based on the improved Y-source inverter,the traditional clamping structure and voltage peak absorption circuit are introduced,and a high step-up and low-voltage stress improved Y-source inverter with the capability of absorbing bus voltage spike is proposed.This topology fully utilizes the structural characteristics of the improved Y-source inverter itself,and further increases the DC-side voltage gain on the basis of ensuring the busbar voltage peak absorption capacity,while reducing the capacitor voltage stress.This paper demonstrates the superiority of the proposed topology over improved Y-source inverter topology by analyzing its working principle and voltage gain,simulation and experiment platform are constructed to perform the circuit simulation and experiment,and the correctness of the theoretical analysis of the proposed inverter and the effectiveness of the busbar voltage peak absorption capacity are verified.

Proposal of High Gain, Reduced Stress with Low-Duty-Cycle Two-Input Boost Converter for Renewable Energy Systems

A two-input boost converter with voltage multiplier cell is proposed in this paper. Then a family of two-input converters with and without voltage multiplier cell are derived and their results are compared to achieve high voltage gain, low duty cycle, and reduced voltage stress. From the analysis of different topologies, a modified two-input converter with two-stage voltage multiplier cell has good operating characteristics. The switch voltage stress and duty cycle of the modified converter is significantly very less than that of the other converter topologies. The modified DC-DC converter with 50% duty cycle achieves a voltage gain of 10 and the results are verified by using MATLAB/Simulink software.

Fault-tolerance wide voltage conversion gain DC/DC converter for more electric aircraft

In this paper,a fault-tolerance wide voltage conversion gain DC/DC converter for More Electric Aircraft(MEA)is proposed.The proposed converter consists of a basic Cuk converter module and n expandable units.By adjusting the operation state of the expandable units,the voltage conversion gain of the proposed converter could be regulated,which makes it available for wide voltage conversion applications.Especially,since mutual redundancy can be realized between the basic Cuk converter module and the expandable units,the converter can continuously work when an unpredictable fault occurs to the fault-tolerant parts of the proposed converter,which reflects the fault tolerance of the converter and significantly improves the reliability of the system.Moreover,the advantages of small input current ripple,automatic current sharing and low voltage stress are also integrated in this converter.The working principle and features of the proposed converter are mainly introduced,and an experimental prototype with 800 W output power has been manufactured to verify the practicability and availability of the proposed converter.

CMOS Dual-Band Low Noise Amplifer

A CMOS dual-band low noise amplifer (LNA) design is presented.The purpose of th is work is intended to substitute only one LNA for two individual LNA's in dual -band transceivers for applications such as wireless local area network complying with both IEEE 802.11a and 802.11b/g.Dua l-band simultaneous input power and noise matching and load shaping are discuss ed.The chip is implemented in 0.25μm CMOS mixed and RF process.The measured pe rformance is summarized and discussed.

Modified Diode Assisted Extended Boost Quasi Z-Source Inverter for PV Applications

The design, simulation and implementation of modified diode assisted extended boost q-ZSI (MDAEB q-ZSI) for photovoltaic application are proposed in this paper. It is the most efficient topology that provides a single stage conversion for PV systems by providing high input voltage gain, reduced number of components count, increased voltage boost property, reduced voltage ratings, reduced voltage stress across the switches and simplified control strategies. Its unique capability in single stage conversion with improved voltage gain is used for voltage buck and boost function. The operating modes and the steady state theoretical analysis of voltage boost, control methods and a system design guide for the proposed topology are investigated in this paper. A simulation model of the PV system based on MDAEB q-ZSI has been built in MATLAB/ SIMULINK. Performance parameters such as Total harmonic distortion (THD), voltage gain, voltage stress and boost factor are computed and compared with the conventional quasi z-source inverter. The prototype model for MDAEB q-ZSI is developed and the results are validated.

Switched-capacitor Based Seven-level Boost Inverter with a Reduced Number of Devices

The conventional multilevel inverters(MLIs)have the disadvantages of numerous devices,incapacity of boost,unbalance for capacitor’s voltage,high complexity for control,and etc.Motivated by this issue,a seven-level boost inverter(7LBI)based on a switched capacitor is presented for singlephase applications in this paper.The proposed 7LBI using only seven transistors can achieve seven output levels,1.5 voltage gain,and natural balance of capacitors’voltages without sensors or other auxiliary methods,which illustrates its suitability for the applications of renewable energy generation.The configuration of topology and operating principles are illustrated in detail.The natural balance of capacitors and capacitance calculations are deduced as well.Moreover,the comparative study is conducted for different types of MLIs.The results illustrate the merits of the proposed 7LBI with respect to reduced devices,lower voltage stress,and less power loss.Finally,a simulation for the proposed 7LBI with PWM modulation is realized based on the theoretical analysis;an experimental prototype is also implemented,verifying multilevel output,boost ability,natural balance for switched capacitors,and performance of transient response.

Single-source Switched-capacitor Boost Nine-level Inverter with Reduced Components

Increasing demands for improvement in power quality and power capacity have contributed to development of switched-capacitor multilevel inverters(SCMLIs).Recently developed SCMLIs enable single-stage voltage boosting,as well as inversion resulting in step-up ac output.Towards reduction in number of components,this paper introduces a boost type singlesource nine-level(9-level)SCMLI employing two capacitors and three diodes.Owing to the series-parallel connection process,capacitor voltages are inherently balanced and assist in quadruple voltage boosting from a single-source.Maximum voltage stress across semiconductor devices is limited to twice input voltage only.Using a minimum number of components,the proposed SCMLI can be extended to increase voltage levels without additional dc input.Each extension module adds two additional voltage steps in the output while maintaining maximum voltage stress the same as 9-level circuit.Followed by in-depth analysis of circuit operation and power losses,a thorough comparison of recently developed single-phase 9-level MLIs is carried out,which verifies design superiority.Extensive simulation and experimental results are presented to verify the prominent features of the 9-level SCMLI under dynamic operating conditions.

High Step-up SEPIC Converters Based on a Family of Coat Circuit

A family of coat circuits for SEPIC converters to improve their boost capability is presented.The present coat circuit does not contain any active switches,so the voltage conversion ratio of the presented converters can be enhanced without complicating its gate driver and control circuits.Meanwhile,because of the expansibility of the coat circuit,the number of its basic cells can be adjusted regarding the actual application requirements.Moreover,in comparison with a conventional SEPIC converter,voltage stress on power switch and diodes of the presented topology is lower at the same output voltage,and thus semiconductor components with low on-resistance are chosen to improve conversion efficiency of converter.The operational principle and steady state analysis of the SEPIC converter with one of the proposed coat circuits have been discussed in detail,and a 300W laboratory prototype is implemented to prove the theoretical analysis of presented converter.

Non-isolated Step-up DC-DC Converter Based on Switched Capacitor Cells

A non-isolated high gain step-up DC-DC converter for low power applications is suggested in this study.In the designed transformerless converter,the main switch current and voltage stress is reduced while maintaining high voltage gain.For instance,with a duty cycle of 0.5 a voltage gain equal to 5 is achieved while the normalized switch voltage stress is 0.4.Also,it decreases power losses of active and passive elements.In the proposed converter design,the switched-capacitor(SC)technique is used to obtain maximum voltage transfer gain using only one switch.The three modes of operation,i.e.,continuous conduction mode(CCM),boundary conduction mode(BCM),and discontinuous conduction mode(DCM),are studied in detail.The small signal analysis(SSA)of the designed converter is investigated,and its steady-state model is examined under CCM.Performance of the proposed converter proposed in this study is assessed and tested using a prototype.Efficiency of the converter is recorded above 94%in a wide range of output powers.Overall,compared to the other converters,the results suggest satisfactory performance of the designed converter.An issue of the proposed converter is that its input current is not smooth due to using the switched-capacitor cell in its structure.This issue is alleviated by using input filters.

High-performance heterogeneous complementary inverters based on n-channel MoS2 and p-channel SWCNT transistors

Heterogeneous complementary inverters composed of bi-layer molybdenum disulfide （MoS2） and single-walled carbon-nanotube （SWCNT） networks are designed, and n-type MoS2/p-type SWCNT inverters are fabricated with a backgated structure. Field-effect transistors （FETs） based on the MoS2 and SWCNT networks show high electrical performance with large ON/OFF ratios up to 106 and 105 for MoS2 and SWCNT, respectively. The MoS2/SWCNT complementary inverters exhibit Vin-Vout signal matching and achieve excellent performances with a high peak voltage gain of 15, a low static-power consumption of a few nanowatts, and a high noise margin of 0.45VDD, which are suitable for future logic-circuit applications. The inverter performances are affected by the channel width-to-length ratios （W/L） of the MOSR-FETs and SWCNT-FETs. Therefore, W/L should be optimized to achieve a tradeoff between the gain and the power consumption.

Developing a Super-lift Luo-converter with Integration of Buck Converters for Electric Vehicle Applications

In this paper,a DC-DC multi-port converter is introduced by integrating a super-lift and a buck converter(SLBC).The proposed single-input dual-output(SIDO)converter has conventional positive output voltage super-lift advantages while simultaneously generating a step・up voltage by Luo・converter and a step-down voltage by the buck converter.In this structure,without utilizing electromagnetic components to generate a dual output,the ripple in output voltages is kept low.Meanwhile,the introduced SLBC has a simple structure and an appropriate control method providing a wide range of output voltages.Besides,to illustrate the advantages of the proposed SIDO converter,a comparison with other similar configurations is carried out.Also,simulation and experiment results indicate a considerable reduction in conduction losses compared to other SIDO converters in the same situations.The operation accuracy of SLBC is validated by performing several simulations in PSCAD/EMTDC software and testing a 150W prototype in the laboratory.

High step-up quasi-Z-source DC–DC converters with single switched capacitor branch

Aiming to integrate the respective merits of the switched-capacitor converter and the quasi-Z-source converter. An novel high step-up quasi-Z-source DC–DC converter with a single switched-capacitor branch is proposed. Compared to other high boost DC–DC converters,the proposed converter can provide higher output voltage gain, lower current stress across the switches, and lower voltage stress across the output diodes by using the same or similar passive and active components. Therefore, the efficiency and reliability of the converter can be improved.The topological derivation, operating principle, parameter selection, and comparison with other DC–DC converters are presented. Finally, both simulations and experimental results are given to verify the characteristics of the proposed converter.

A low-phase-noise LC-VCO with an enhanced-Q varactor for use in a high-sensitivity GNSS receiver

An LC-VCO with an enhanced quality factor（Q） varactor for use in a high-sensitivity GNSS receiver is presented.An enhanced A-MOS varactor is composed of two accumulation-mode MOS（A-MOS） varactors and two bias voltages,which show the improved Q and linearization capacitance-voltage（C-V） curve.The VCO gain（K_（vco）） is compensated by a digital switched varactors array（DSVA） over entire sub-bands.Based on the characteristics of an A-MOS,the varactor in a DSVA is a high Q fixed capacitor as it is switched off,and a moderate Q tuning varactor when it is switched on,which keeps the maximal Q for the LC-tank.The proposed circuit is fabricated in a 0.18μm 1P6M CMOS process.The measured phase noise is better than -122 dBc/Hz at a 1 MHz offset while the measured tuning range is 58.2%and the variation of K_（VCO） is close to±21%over the whole of the sub-bands and the effective range of the control voltage.The proposed VCO dissipates less than 5.4 mW over the whole operating range from a 1.8 V supply.