scholarly journals A Single-Phase Embedded Z-Source DC-AC Inverter

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Se-Jin Kim ◽  
Young-Cheol Lim

In the conventional DC-AC inverter consisting of two DC-DC converters with unipolar output capacitors, the output capacitor voltages of the DC-DC converters must be higher than the DC input voltage. To overcome this weakness, this paper proposes a single-phase DC-AC inverter consisting of two embedded Z-source converters with bipolar output capacitors. The proposed inverter is composed of two embedded Z-source converters with a common DC source and output AC load. Though the output capacitor voltages of the converters are relatively low compared to those of a conventional inverter, an equivalent level of AC output voltages can be obtained. Moreover, by controlling the output capacitor voltages asymmetrically, the AC output voltage of the proposed inverter can be higher than the DC input voltage. To verify the validity of the proposed inverter, experiments were performed with a DC source voltage of 38 V. By controlling the output capacitor voltages of the converters symmetrically or asymmetrically, the proposed inverter can produce sinusoidal AC output voltages. The experiments show that efficiencies of up to 95% and 97% can be achieved with the proposed inverter using symmetric and asymmetric control, respectively.

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 394 ◽  
Author(s):  
Dai-Van Vo ◽  
Minh-Khai Nguyen ◽  
Duc-Tri Do ◽  
Youn-Ok Choi

A novel single-phase nine-level boost inverter is proposed in this paper. The proposed inverter has an output voltage which is higher than the input voltage by switching capacitors in series and in parallel. The maximum output voltage of the proposed inverter is determined by using the boost converter circuit, which has been integrated into the circuit. The proposed topology is able to invert the multilevel voltage with the high step-up output voltage, simple structure and fewer power switches. In this paper, the circuit configuration, the operating principle, and the output voltage expression have been derived. The proposed converter has been verified by simulation and experiment with the help of PSIM software and a laboratory prototype. The experimental results match the theoretical calculation and the simulation results.


2018 ◽  
Vol 28 (01) ◽  
pp. 1950014
Author(s):  
Ghasem Haghshenas ◽  
Sayyed Mohammad Mehdi Mirtalaei ◽  
Hamed Mordmand ◽  
Ghazanfar Shahgholian

In this paper, a novel high step-up single switch DC–DC converter with soft switching is presented. The main application of this converter is the connection of photovoltaic (PV) system to a 400[Formula: see text]V DC-bus. The proposed converter achieves high step-up voltage gain with small duty cycle by a combined boost and fly-back topology. Also, its switch voltage stress is lower than the output voltage. Besides, in the proposed converter, any auxiliary switch or magnetic core has not been used — therefore, the number of converter components has not been increased much in comparison with the conventional boost-fly-back converter. The operation principles of the converter and its theoretical operation waveforms are presented. In order to evaluate the theoretical analysis, a prototype of the converter is designed and experimentally implemented. The practical results are presented for a 100[Formula: see text]W boost-fly-back converter with input voltage of 40[Formula: see text]V and output voltage of 400[Formula: see text]V. Also, the output capacitor is designed to have less than 1% ripple on output voltage.


2015 ◽  
Vol 793 ◽  
pp. 315-319
Author(s):  
M. Zhafarina ◽  
M. Irwanto ◽  
A.H. Haziah ◽  
N. Gomesh ◽  
Y.M. Irwan ◽  
...  

Photovoltaic is use to supply electricity from sunlight. Inverter is used to convert the direct current (DC) from photovoltaic to alternating current (AC). This project is to design and develop a single phase inverter that able to invert the input voltage of DC to output voltage of AC using PROTEUS software. The inverter based on 8 bits for one cycle of a driver pulse wave. This simulation used before doing the hardware. This software can save a lot of time on this exact simulation of the prototype.


2015 ◽  
Vol 764-765 ◽  
pp. 471-475 ◽  
Author(s):  
Wei Bin Yang ◽  
Shao Jyun Xie ◽  
Han Hsien Wang

The new digital control loop of the low-dropout regulator (LDO) is presented. It is composed of coarse tracking circuit and fine tracking circuit, and no external output capacitor is required to stabilize the control loop. The proposed method makes the quiescent current lower than conventional analog LDOs. The operational amplifier of the conventional LDO fails to operate at 0.7V, and the developed digital LDO in 0.18um CMOS achieved the 0.7V input voltage and 0.5V output voltage with 99.99% current efficiency and 2.6-μA quiescent current at 20mA load current. Therefore, the proposed DLDO is suitable for low power applications.


Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5107
Author(s):  
Catalina González-Castaño ◽  
Carlos Restrepo ◽  
Fredy Sanz ◽  
Andrii Chub ◽  
Roberto Giral

Many electronic power distribution systems have strong needs for highly efficient AC-DC conversion that can be satisfied by using a buck-boost converter at the core of the power factor correction (PFC) stage. These converters can regulate the input voltage in a wide range with reduced efforts compared to other solutions. As a result, buck-boost converters could potentially improve the efficiency in applications requiring DC voltages lower than the peak grid voltage. This paper compares SEPIC, noninverting, and versatile buck-boost converters as PFC single-phase rectifiers. The converters are designed for an output voltage of 200 V and an rms input voltage of 220 V at 3.2 kW. The PFC uses an inner discrete-time predictive current control loop with an output voltage regulator based on a sensorless strategy. A PLECS thermal simulation is performed to obtain the power conversion efficiency results for the buck-boost converters considered. Thermal simulations show that the versatile buck-boost (VBB) converter, currently unexplored for this application, can provide higher power conversion efficiency than SEPIC and non-inverting buck-boost converters. Finally, a hardware-in-the-loop (HIL) real-time simulation for the VBB converter is performed using a PLECS RT Box 1 device. At the same time, the proposed controller is built and then flashed to a low-cost digital signal controller (DSC), which corresponds to the Texas Instruments LAUNCHXL-F28069M evaluation board. The HIL real-time results verify the correctness of the theoretical analysis and the effectiveness of the proposed architecture to operate with high power conversion efficiency and to regulate the DC output voltage without sensing it while the sinusoidal input current is perfectly in-phase with the grid voltage.


2020 ◽  
Vol 39 (2) ◽  
pp. 589-599
Author(s):  
D.B.N. Nnadi ◽  
S.E. Oti ◽  
C.I. Odeh

Splitting of a dc voltage source with two capacitors has been the approach in generating 5-level output voltage with single- and three-phase full-bridge circuits and added bidirectional switch. Associated with this configuration is the problem of voltage imbalance between the splitting capacitors. In addition, the inverter output voltage magnitude is obviously limited to the value of the split input voltage source. Presented in this paper is a unit topology for single-phase 5-level multilevel inverter, MLI. It simply consists of a full-bridge circuit, a capacitor, charge-discharge unit and a dc source. The charge-discharge unit with the capacitor is the interface between the full-bridge and the dc source. The proposed unit cell can generate a 5-level output voltage waveform whose peak value is twice the input voltage value. For higher output voltage level, a cascaded structure of the developed unit cell is presented. Comparing the proposed inverter with CHB inverter and some recent developed MLI topologies, it is found that the proposed inverter configuration generates higher output voltage value, at reduced component-count, than other topologies, for a specified number of dc input voltages. For two cascaded modules, simulation and experimental verifications are carried out on the proposed inverter topology for an R-L load. Keywords: Cascaded multilevel, Inverter, total harmonic distortion, topologies, waveform


Author(s):  
Jeevan Naik

<span>In this paper, a design and control for the buck-boost converter, i.e., 1-plus-D converter with a positive output voltage, is presented, which combines the 1-plus-D converter and the synchronous rectified (SR) buck converter. By doing so, the problem in voltage bucking of the 1-plus-D converter can be solved, thereby increasing the application capability of the 1-plus-D converter. Since such a converter operates in continuous conduction mode inherently, it possesses the nonpulsating output current, thereby not only decreasing the current stress on the output capacitor but also reducing the output voltage ripple. Above all, both the 1-plus-D converter and the SR buck converter, combined into a buck–boost converter with no right-half plane zero, use the same power switches, thereby causing the required circuit to be compact and the corresponding cost to be down. Furthermore, during the magnetization period, the input voltage of the 1-plus-D converter comes from the input voltage source, whereas during the demagnetization period, the input voltage of the 1-plus-D converter comes from the output voltage of the SR buck converter.</span>


Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1623
Author(s):  
Bor-Ren Lin

In order to realize emission-free solutions and clean transportation alternatives, this paper presents a new DC converter with pulse frequency control for a battery charger in electric vehicles (EVs) or light electric vehicles (LEVs). The circuit configuration includes a resonant tank on the high-voltage side and two variable winding sets on the output side to achieve wide output voltage operation for a universal LEV battery charger. The input terminal of the presented converter is a from DC microgrid with voltage levels of 380, 760, or 1500 V for house, industry plant, or DC transportation vehicle demands, respectively. To reduce voltage stresses on active devices, a cascade circuit structure with less voltage rating on power semiconductors is used on the primary side. Two resonant capacitors were selected on the resonant tank, not only to achieve the two input voltage balance problem but also to realize the resonant operation to control load voltage. By using the variable switching frequency approach to regulate load voltage, active switches are turned on with soft switching operation to improve converter efficiency. In order to achieve wide output voltage capability for universal battery charger demands such as scooters, electric motorbikes, Li-ion e-trikes, golf carts, luxury golf cars, and quad applications, two variable winding sets were selected to have a wide voltage output (50~160 V). Finally, experiments with a 1 kW rated prototype were demonstrated to validate the performance and benefits of presented converter.


Electronics ◽  
2021 ◽  
Vol 10 (16) ◽  
pp. 1886
Author(s):  
Younghoon Cho ◽  
Paul Jang

Fly-buck converter is a multi-output converter with the structure of a synchronous buck converter structure on the primary side and a flyback converter structure on the secondary side, and can be utilized in various applications due to its many advantages. In terms of control, the primary side of the fly-buck converter has the same structure as a synchronous buck converter, allowing the constant-on-time (COT) control to be applied to the fly-buck converter. However, due to the inherent energy transfer principle, the primary-side output voltage regulation of COT controlled fly-buck converters may be poor, which can deteriorate the overall converter performance. Therefore, the primary output capacitor must be carefully designed to improve the voltage regulation characteristics. In this paper, a theoretical analysis of the output voltage regulation in COT controlled fly-buck converter is conducted, and based on this, a design guideline for the primary output capacitor considering the output voltage regulation is presented. The validity of the analysis and design guidelines was verified using a 5 W prototype of the COT controlled fly-buck converter for telecommunication auxiliary power supply.


2017 ◽  
Vol 26 (12) ◽  
pp. 1750196 ◽  
Author(s):  
Yanzhao Ma ◽  
Yinghui Zou ◽  
Shengbing Zhang ◽  
Xiaoya Fan

A fully-integrated self-startup circuit with ultra-low voltage for thermal energy harvesting is presented in this paper. The converter is composed of an enhanced swing LC oscillator and a charge pump with decreased equivalent input capacitance. The LC oscillator has ultra-low input voltage and high output voltage swing, and the charge pump has a fast charging speed and small equivalent input capacitance. This circuit is designed with 0.18[Formula: see text][Formula: see text]m standard CMOS process. The simulation results show that the output voltage is in the range of 0.14[Formula: see text]V and 2.97[Formula: see text]V when the input voltage is changed from 50[Formula: see text]mV to 150[Formula: see text]mV. The output voltage could reach 2.87[Formula: see text]V at the input voltage of 150[Formula: see text]mV and the load of 1[Formula: see text]M[Formula: see text]. The maximum efficiency is in the range of 10.0% and 14.8% when the input voltage is changed from 0.2[Formula: see text]V to 0.4[Formula: see text]V. The circuit is suitable for thermoelectric energy harvesting to start with ultra-low input voltage.


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