High-Gain Seven-Level Switched-Capacitor Two-Stage Multi-Level Inverter (original) (raw)
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IET Renewable Power Generation
To proceed to a net zero carbon world and to mitigate the environmental challenges associated with it, integration speed of renewable energy sources such as photovoltaic (PV) systems has been increased around the world. Here, an improved switched-capacitor based nine-level inverter is introduced for PV applications. This topology has several benefits such as, voltage boosting feature, using a single DC source, reduction of capacitor charging current spike and extendable input voltage. This inverter produces nine-level output voltage waveform using single power supply. This topology, using identical two capacitors in parallel with a single DC source, can boost the input voltage. In this inverter to limit spike current of capacitor charging mode, an inductor is placed in the charging path of capacitors with a parallel diode. The power losses and overall efficiency analysis of the improved inverter are considered. To verify the accurate performance of inverter under a step change on power flows, simulation results are obtained by MATLAB/Simulink software and presented. To highlight the benefits of the inverter, a comparison of improved topology with most recent topologies is performed. Finally, to verify the feasibility and performance of the improved inverter, experimental results of a 770 W grid-tied prototype are presented.
This paper explains a high efficient seven level inverter for PV electric generation system, which is collected of a dc/dc power converter and a new seven-level inverter. The dc/dc power converters incorporate a dc–dc boost converter and a transformer to change the output voltage of the solar cell array into two self-governing voltage sources with multiple associations. This new seven-level inverter is configured using a capacitor assortment circuit and a full-bridge power converter, associated in cascade. The capacitor assortment circuit changes the two output voltage sources of dc–dc power converter into a three-level dc voltage, and the full-bridge power converter additionally converts this three-level dc voltage into a seven-level ac voltage. Considering this technique, the projected solar PV electric generation system generates a sinusoidal productivity current that is in segment with the utility voltage and is fed into the service. The outstanding features of the prospect planned seven-level inverter are that only six power electronic switches are used, and only one power electronic switch is switched at elevated frequency at whichever time. A model is developed and experienced to authenticate the presentation of this projected solar power PV electric generation scheme.
Design and development of photovoltaic solar system based single phase seven level inverter
Bulletin of Electrical Engineering and Informatics
For solar photovoltaic (PV) systems, an upgraded triple gain seven-level inverter that works both independently and while connected to the grid is proposed. The two-stage configuration of the system is boost cascaded. The first stage has a one switch improved gain converter (OSIGC) to increase and normalize the input direct current (DC) voltage, and the second stage includes a unique seven level alternating current (AC) is produced via a multilevel inverter (MLI) design with triple voltage gain. The proposed OSIGC is appropriate for a broad range of conversions. The voltage gain in MLI was achieved using switched capacitor techniques. The DC-DC converter can achieve a maximum voltage gain of twelve and the MLI can achieve a maximum voltage gain of three, resulting in a DC-DC-AC voltage that can reach 36. Maximum power point tracking (MPPT) technique based on modified perturb and observe (P&O) is used in OSIGC to maximise PV module power utilisation, and MLI control utilises sinusoidal pulse width modulation (SPWM) realistically. For the purpose of analysing the suggested system, a 200 Watt prototype statel is created. With a total harmonic distortion (THD) of 0.181%, up to 92.12% of the converter system's overall efficiency is possible.
Seven Level T-Type Switched Capacitor Inverter Topology for PV Applications
IEEE Access, 2021
The conventional neutral point clamped (NPC) multilevel inverter topology needs voltage balancing circuits to balance the dc-link capacitor, the number of component count is high and output voltage is half of the input voltage which increase the size of the source side dc/dc converter in PV applications. In this paper, a new topology of seven level neutral point clamped inverter is developed. The proposed inverter has a self-voltage boosting capability using a floating capacitor to boost the output voltage one and half of the input voltage. In this proposed topology, no additional sensors are required for the floating capacitor voltage stability, which results in minimizing the complexity of designing the inverter. The direct link between the neutral point and the mid-point of the dc-link capacitors significantly reduces the leakage current and common mode voltage in this inverter. A thorough comparison between the developed topology and recent suggested topologies is carried out which set the benchmark for the proposed one due to its lower switch count and higher voltage gain. The proposed topology is verified in simulation and prototype hardware model and results are discussed with dynamic load variations. The efficiency of the inverter is 97.1% @200W and low as 88.1 % @ inductive load. The voltage THD is 17.01% for simulation and 19.3% I for experimental is results. INDEX TERMS Switched capacitor circuits, seven level inverter, ANPC type, voltage boosting, self-voltage balancing.
A New Switched-Capacitor Based Boost Multilevel Inverter Topology with Higher Voltage Gain
IET Power Electronics
This paper proposes a new switched-capacitor (SC) based multilevel inverter topology with a single dc voltage source. The proposed topology finds its suitability for renewable energy applications with low voltage. Seven-level (7L) output voltage is achieved across the load with triple voltage gain employing two capacitors and 12 switches. Self-voltage balancing of capacitor voltages, parallel operation of capacitors during discharging mode, reduced voltage stress, and bipolar output voltage generation without using backend H-bridge are the major features of the proposed topology. Furthermore, a generalized structure of the proposed topology has also been discussed in this paper. A comparison with other similar topologies with single-source 7L configuration has been carried out to show the advantages of the proposed topology with reduced switch count. Experimental results have been provided to verify the performance of the proposed topology with different operating conditions.
2021
With growing demand for green energy such as solar energy, multilevel inverters are the focus of research due to their adequate cost, compactness, and high efficiency. A novel 9-level multilevel inverter (SCMLI) topology based on switched capacitor technique is presented first. The structure utilizes 2 non-isolated power sources and reduced components to realize higher number of output voltage levels. The structure has the ability to produce boosted output voltage from lower voltage input. Further, it can balance the capacitor voltages using simple switching states. In addition, the structure does not use H-bridge circuit for polarity generation which reduces total standing voltage of the structure. Phase disposition high frequency modulation strategy is used to switch the inverter. To validate this SCMLI, simulation study for 9 voltage levels has been carried out considering different kinds of load conditions. For this proposed SCMLI structure, an extended structure has been developed, which can cost effectively produce as much voltage levels as possible with least circuit complexity.
— One of the important applications of power electronic converters is in low power Renewable Energy Generation Systems (REGS). In this paper a new application for single phase grid connected switched capacitor multilevel inverter in REGS has been proposed. According to control strategy and Seri-parallel switching of semiconductors, it has controllable output voltage amplitude with low total harmonic distortion in compare with similar topologies, and it does not have any complicated algorithm for balancing the capacitors voltage, respectively. In this study, a powerful method for maximum power point tracking (MPPT) under mismatching condition and grid-connected PV principles, based on 5-level inverter extracted from proposed general Switched Capacitor Multilevel Inverter (SCMLI) topology, is recommended. In this case, due to boost inherent capability of proposed SCMLI, the conventional dc/dc converter which usually used in the PV modules array to reinforce the input dc voltage has been removed. Hereby proposed MPPT strategy can track the maximum power of PV module directly on the basis of changing the provided phase difference between the inverter voltage and grid. In the rest of the paper, various simulation results by PSCAD/EMTDC software are presented to show the effectiveness of the proposed technique.
A novel five-level switched capacitor type inverter topology for grid-tied photovoltaic application
2020 IEEE Applied Power Electronics Conference and Exposition (APEC), 2020
This paper presents a novel five-level inverter topology and associated control scheme. The proposed structure consists of a capacitor, and eight active switching elements. It requires only one dc source and is capable of generating five voltage levels with double voltage boosting gain. On the other hand, it does not require any control scheme to balance the capacitor in the DC-bus due to inherent voltage balancing capability. As a result, the control complexity reduces a lot. Brief analysis followed by simulation and measurement results of a proposed 5-level inverter using the finite control set model predictive control (FCS-MPC) algorithm is presented. Detail of the analysis with more measurement result and comparison will be presented in the final paper.
A new multilevel inverter topology based on switched-capacitor technique
International Journal of Power Electronics and Drive Systems (IJPEDS), 2021
This paper presents a new multilevel inverter based on the switchedcapacitor technique. The topology aims for renewable energy and fuel cell applications that demand high magnitude output ac voltage. This configuration of the inverter can produce a total of thirteen voltage levels using a single DC source. The topology features voltage boosting with a triple gain of the input voltage source without utilizing a boost DC-DC converter. Furthermore, the voltages of the capacitors are self-balanced at any desired voltage level during each cycle. Therefore, auxiliary circuits are no longer needed. A comparative study of the presented inverter with the classical topologies and recently introduced topologies has been done in power switches, driver circuits, blocking voltage of the switches, and boosting the input voltage. A simple fundamental switching scheme is applied to the proposed topology to validate the viability of the topology.
The 27-level multilevel inverter for solar PV applications
2012 IEEE 5th India International Conference on Power Electronics (IICPE), 2012
Multilevel voltage source inverter offer several advantages compared to their conventional counterparts. Cascaded H-bridge inverter provides Stepped AC voltage wave form with lesser harmonics at higher levels by combining different ranges of voltage DC sources and the filter components are reduced by increasing Step levels. By increasing the level of the inverter we can get several advantages: get a good voltage wave form, Very low THD, reduced volume and cost. The need of several sources on the DC side of the converter makes multilevel technology attractive for photovoltaic applications. This paper provides an overview of a multilevel inverter topology and investigates their suitability for single-phase photovoltaic systems. A simulation model is based on MATLAB/SIMULINK is developed. An experimental 40W prototype inverter was builted and tested. The results is experimentally validate for the proposed SPWM based three H-bridge 27 level cascaded multilevel inverter.