Quasi-Switched Boost Research Articles

A Novel Three-Level Quasi-Switched Boost F-Type Inverter With High Voltage Gain and Self-Balanced Neutral-Point Voltage

This paper introduces a new topology of three-level quasi-switched boost F-type inverter (3L-qSBFTI) to improve voltage gain compared to traditional impedance-source inverters (ISIs). This topology uses a switched-capacitor (SC) structure to increase the boost factor to twice that of traditional ISIs. Unlike any conventional SC circuit, the current through capacitors when they are connected in parallel is limited by inductor current. Hence, there is no inrush current through capacitors and semiconductor devices in this operating state. Furthermore, this SC structure helps to obtain self-balanced neutral-point-voltage. The lower-shoot-through (LST) state, which is inserted into P-type small vectors, is used to boost the DC-link voltage. This insertion helps to increase modulation index utilization. As a result, the component voltage rating of the introduced inverter is significantly improved. The comparison study, simulation, and experimental validations have been presented to verify the proposed inverter.

High-Gain Quasi-Switched Boost Inverter With Single Inductor and Continuous Input Current

The unique advantages of impedance source inverters make them more suitable for new energy fields that need to boost and invert low dc voltages. In order to enhance the boost capability, this work derives a new high-gain quasi-switched boost inverter (HG-qSBI) from the original qSBI topology. Specifically, the voltage gain is improved from 1/(1-2 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</i> ) to 1/(1-3 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</i> ) by adding one switched-capacitor unit formed by one capacitor, one transistor, and two diodes, here <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</i> is the duty ratio for shoot-through states of the inverter. It inherits the advantages of single inductor and continuous input current, and the modulation strategy is exactly the same as the original qSBI. Moreover, all components employed in the HG-qSBI withstand the same voltage stress. All these features are verified by both three-phase simulation and single-phase experimental results.

Transformer-Less Switched-Capacitor Quasi-Switched Boost DC-DC Converter

In this article, a quasi-switched boost converter based on the switched-capacitor technique with high step-up voltage capability is dealt with and analyzed. The proposed converter offers a simple structure and low voltage stress on the semiconductor elements with intrinsic small duty cycle. An inductor of the proposed converter is connected in series with the input voltage source; therefore, continuous input current ripple is attainable. In addition, the efficiency of the proposed converter is also improved. A detailed steady-state analysis is discussed to identify the salient features of the switched-capacitor-based quasi-switched boost DC-DC converter. The performance of the converter is compared against similar existing high boost DC-DC converters. Finally, the switched-capacitor-based quasi-switched boost DC-DC converter is investigated by experimental verification.

High Gain Isolated Quasi-Switched Boost Converter Embedded with Switched Capacitor Cell

—A DC–DC converter that can deliver high gain and isolation using quasi-switched boost and switched capacitor cell (qSB-SC) is proposed. This converter is well suited for renewable energy applications, where generally, low voltage input sources are available. The converter circuit presented in this work consists of four stages. The first stage comprises a quasi-switched boost network with an inductor. A SC cell is embedded in the second stage that can further boost the voltage. The third stage has a push-pull converter with a high-frequency transformer. In the fourth stage, there is a voltage doubler rectifier circuit which again enhances the boost capability. Detailed analysis pertaining to selection of circuit elements used in the converter is also derived. The proposed converter is compared with few state-of-the-art competitive topologies to prove its high boost ability. A 250 W prototype of the proposed converter is realized with an output voltage of 400 V when fed from a 30 V input source. The results obtained concur well with the simulated and theoretical results. The merits of the converter are (i) continuous ripple-free source and load current, (ii) galvanic isolation, and (iii) very high gain.

The Three-Carrier Quasi Switched Boost Inverter Control Technique

This paper presents a carrier modulation technique to control the three-phase, two-level quasi switched boost inverter. This PWM algorithm uses three carrier waves, the first of which is for the inverter while the others are for the booster. The boost factor depends on the short circuit interval on the DC/DC booster and the inverter. When the short circuit interval on the DC boost is twice that on the inverter, the modulation index can be enlarged. The new algorithm is analyzed, calculated, simulated, and tested. The analysis and calculation results show that the proposed technique can reduce the voltage on the DC link capacitor compared to a conventional approach. It can reach 22.16% when the ratio of the DC source voltage to the effective reference voltage is 0.5. The modulation index can extend to 29% under these conditions and the current ripple in the boost inductor can be reduced by 4.8%. The simulation and experimental results also show similarities, thereby confirming the analysis and calculation.

Topological Review of Quasi-Switched Boost Inverters

This paper presents a comprehensive review based on the features and drawbacks of the quasi-switched boost inverter (qSBI) topologies. The qSBI derived configurations are well suitable for low power applications due to their reduced number of components. This work focuses on the topological review of qSBI derived topologies and serves as a reference for further derivation and research on the selection of suitable topology for the specific renewable energy applications, particularly based on the photovoltaic (PV) converters.

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.

Single stage Boost Cascaded Multilevel Inverter Based on Switched Inductor Structure

This paper presents the experimental investigations of Switched Inductor cell (SL-FLCHBqSBI) based Five-Level Cascaded H-Bridge quasi Switched Boost Inverter for Renewable Energy (RE) applications. The SL-FLCHBqSBI topology is based on the ripple input current Switched Inductor Boost Inverter (SLBI) structure which is available in the literature. In this work, a stiff DC voltage of 36 V is taken as input to deliver a power of 100 W across a resistive load is designed. The control signals for the active devices are generated using Phase-Shifted sinusoidal Pulse Width Modulation (PS-PWM) modulation technique. The SL-FLCHBqSBI topology provides a higher voltage gain of 2.83 compared to the conventional topologies for a low duty ratio. The simulation is performed in MATLAB/Simulink environment and the simulation results are presented. A hardware set up is implemented and experiments are carried out to check the consistency of the theoretical concepts with the working of the proposed topology in practical.

Design and Implementation of a Dual DC Source-based Quasi-Switched Boost Inverter for Renewable Energy Applications

ABSTRACT Recently, single-stage boost inverter topologies like Z-Source Inverter (ZSI), Switched Boost Inverter (SBI) and quasi-Switched Boost Inverter (qSBI) are gaining more attention in Renewable Energy Source (RES) applications. This paper proposes a dual dc source-based qSBI (DqSBI) topology which can be used as a micro-inverter for integrating various RES like solar photovoltaic, fuel cell etc. This study explains the principle of operation, design and steady-state analysis of the DqSBI topology. It also presents a performance comparison with conventional dc-dc boosted inverter and SBI topologies. The proposed inverter topology can achieve high voltage gain with low voltage stress across the switch, capacitor and diode. By using shoot through duty ratio, this topology provides a 110 V (rms) ac from a 324 V dc link voltage. The dc link voltage is obtained from a dc source of 36 V. The THD in the output voltage is 4.13%. Due to the reduced THD, the filter size and cost of the entire system are reduced. A 200-W laboratory prototype is developed to verify the theoretical concepts with an output voltage of 110 V (rms)/50 Hz. The Simple Boost Control (SBC) modulation strategy is used to generate shoot through and non-shoot through pulses. The modulation control algorithm is implemented using Spartan −3E Field Programmable Gate Array (FPGA) processor.

DC-Link Quasi-Switched Boost Inverter With Improved PWM Strategy and its Comparative Evaluation

Low voltage stress on the impedance source network devices is the main reason for the advent of DC-linked type quasi-switched boost inverters (DqSBIs). However, the DqSBI has become less attractive due to its low voltage gain. This paper presents a novel PWM control strategy for the DqSBI and its comparative performance evaluation to the conventional inverters. The modified PWM control strategy based DqSBI improves the voltage gain and reduces the conduction loss and the inductor current ripple. Circuit analysis and comparison study between the DqSBI, the quasi-Z-source inverters, and the two-stage inverter with a boost DC-DC converter are presented. 1-kVA three-phase inverter prototypes were set up to compare and evaluate the performance of the DqSBI with the improved PWM method for voltage gains of 0.85 to 1.6. The measured efficiency and total harmonic distortion (THD) values are also presented.

Switched-Capacitor-Based Neutral-Point-Clamped Quasi-Switched Boost Multilevel Inverter

Reliable and efficient inverters are becoming essential in the current scenario of electrical power generation from renewable energy sources. Owing to inherent buck–boost ability and shoot-through immunity, the single-stage inverters are getting solid evaluation as compared to conventional inverters in the present era of renewable energy generation. However, the maximum attainable boosting of the single-stage inverters is limited by means of device stresses and spectral performance. This paper proposes a switched-capacitor-based quasi-switched boost neutral-point-clamped single-stage multilevel inverter. It is able to make desired AC output voltage in a single-stage conversion from a low-level DC voltage engendered by renewable sources such as fuel cell and PV cell. Further, it can attain high voltage gain at reduced voltage stresses on the switches, capacitors and diodes by cascading multiple switched-capacitor cells to quasi-switched boost network. The working principle and steady-state analysis of proposed topology are presented in order to obtain mathematical relation between input and output voltages. The effectiveness of the proposed inverter has been compared with other impedance-source multilevel inverters in terms of voltage gain, boosting capability, voltage stresses and efficiency. The operation of the proposed system is verified by MATLAB simulation. Also, a laboratory prototype is built and tested to verify the theoretical analysis.

High Voltage Gain Quasi-Switched Boost Inverters With Low Input Current Ripple

Two high voltage gain quasi-switched boost inverters (HG-qSBIs) are introduced in this paper. The proposed HG-qSBIs has the following characteristics: 1) continuous input current with low ripple; 2) reduced voltage stress on the capacitor, switch, and diodes; 3) shoot-through immunity; 4) achieved high voltage gain with single-stage conversion; and 5) improve the output voltage capability with using high modulation index. A novel pulse-width modulationcontrol technique is proposed for the introduced HG-qSBI. Operating principle, circuit analysis, and passive component design guideline of the HG-qSBI are addressed. Comparison analysis between the introduced HG-qSBI and other Z-source-based high voltage gain inverters is presented. A prototype is made to test the introduced HG-qSBI. Simulation and experimental verifications are shown to prove the accuracy of the theoretical analysis.

Voltage Multiplier Cell-Based Quasi-Switched Boost Inverter with Low Input Current Ripple

A novel single-phase single-stage voltage multiplier cell-based quasi-switched boost inverter (VMC-qSBI) is proposed in this paper. By adding the voltage multiplier cell to the qSBI, the proposed VMC-qSBI has the following merits; a decreased voltage stress on an additional switch, a high voltage gain, a continuous input current, shoot through immunity, and a high modulation index. A new pulse-width modulation (PWM) control strategy is presented for the proposed inverter to reduce the input current ripple. To improve the voltage gain of the proposed inverter, an extension is addressed by adding the VMCs. The operating principle, steady-state analysis, and impedance parameter design guideline of the proposed inverter are presented. A comparison between the proposed inverter and other impedance source-based high-voltage gain inverters is shown. Simulation and experimental results are provided to confirm the theoretical analysis.

Switched-Capacitor Quasi-Switched Boost Inverters

In this paper, two switched-capacitor quasi-switched boost inverters (qSBIs) are proposed. By adding one capacitor and one diode to the qSBIs, the proposed inverters achieve high voltage gain with low voltage stress on active switches, capacitors, and diodes. The proposed inverters can extend to n -cell for voltage gain improvement. The operating principle, steady-state analysis, and impedance parameter selections of the proposed inverter are presented. A full comparison between the proposed inverter and other impedance-source inverters is addressed. A 500-W prototype is built to verify the operating theory of the proposed inverter in both the standalone mode and the grid-connected mode. Simulation and experimental results validate the theoretical analysis.

A Single-Phase Cascaded H-bridge Quasi Switched Boost Inverter for Renewable Energy Sources Applications

A Single-Phase Cascaded H-bridge Quasi Switched Boost Inverter for Renewable Energy Sources Applications

A Class of Quasi-Switched Boost Inverters

A switched boost inverter (SBI) can replace a $Z$ -source inverter (ZSI) in low-power applications because it has one less $LC$ pair than the ZSI. This paper presents a class of quasi-SBIs (qSBIs) that offers several advantages when compared with a conventional SBI, including reducing the voltage stress on the capacitor, increasing the boost voltage factor, and improving input current profiles. Operating principles, steady-state analysis, and comparisons with conventional inverters are presented. A prototype based on a TMS320F28335 digital signal processor is built to verify the operating principle of the proposed qSBIs.