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Proceedings ArticleDOI

Maximum Power Point Tracking for Photovoltaic-Fed Multi-Source Switched Capacitor Based Multilevel Inverter

20 Mar 2020-

TL;DR: In this paper, a shifting carrier based maximum power point tracking (MPPT) algorithm for multisource converters is proposed and is able to track the maximum power under varying irradiance levels.
Abstract: In this paper, a shifting carrier based maximum power point tracking (MPPT) algorithm for multisource converters is proposed. This MPPT algorithm is explained for both low frequency (constant carrier) and high frequency (triangular) carrier signals. The proposed algorithm is applied for a single stage multisource switched capacitor based multilevel inverter for grid connected and stand-alone photovoltaic applications. This converter features high gain, less component count, self capacitor charge balancing, better dispersed value of sources and increased source utilization. The importance of selecting an appropriate pulse width modulation technique for switched capacitor based inverters in order to maintain the capacitor charging time is explained. The proposed technique is able to track the maximum power under varying irradiance levels. The experimental results of the proposed algorithm is presented. The MPPT technique is analyzed and verified in simulation for stand-alone and grid connected applications using MATLAB/Simulink platform.
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Journal ArticleDOI
Bailu Xiao1, Lijun Hang1, Jun Mei2, Cameron Riley1  +2 moreInstitutions (3)
Abstract: This paper presents a modular cascaded H-bridge multilevel photovoltaic (PV) inverter for single- or three-phase grid-connected applications. The modular cascaded multilevel topology helps to improve the efficiency and flexibility of PV systems. To realize better utilization of PV modules and maximize the solar energy extraction, a distributed maximum power point tracking control scheme is applied to both single- and three-phase multilevel inverters, which allows independent control of each dc-link voltage. For three-phase grid-connected applications, PV mismatches may introduce unbalanced supplied power, leading to unbalanced grid current. To solve this issue, a control scheme with modulation compensation is also proposed. An experimental three-phase seven-level cascaded H-bridge inverter has been built utilizing nine H-bridge modules (three modules per phase). Each H-bridge module is connected to a 185-W solar panel. Simulation and experimental results are presented to verify the feasibility of the proposed approach.

374 citations


"Maximum Power Point Tracking for Ph..." refers methods in this paper

  • ...The MPPT technique presented in [20] generates separate reference signals for each source increasing the complexity....

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  • ...Different MPPT techniques are presented in the literature for multi-source converters (such as cascaded H-bridge) [20]–[23]....

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  • ...Thus, the capacitors are made to charge in binary asymmetric pattern i.e., the capacitors are charged to voltages equal to Vc,i = 2 i−1(V1+V2+ ...+Vk) for i = 1, 2, ..., n. (1) The H-bridge is made to operate at low (line) frequency to obtain the negative voltage levels....

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  • ...A feed-forward proportional carrier-based MPPT technique is presented in [23] for multisource cascaded H-bridge topology....

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  • ...Basic multilevel inverters such as flying capacitor, diode clamped and cascaded H-bridge converters require more number of components....

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Journal ArticleDOI
TL;DR: Two new topologies are proposed for multilevel inverters that reduce the number of switches and isolated dc voltage sources, the variety of the dc voltage source values, and the size and cost of the system in comparison with the conventional topologies.
Abstract: In this paper, two new topologies are proposed for multilevel inverters. The proposed topologies consist of a combination of the conventional series and the switched capacitor inverter units. The proposed topologies reduce the number of switches and isolated dc voltage sources, the variety of the dc voltage source values, and the size and cost of the system in comparison with the conventional topologies. In addition, the proposed topologies can double the input voltage without a transformer. There is no need for complicated methods to balance the capacitor voltage. The simulation and experimental results of single-phase 25- and 17-level inverters are given to prove the correct operation of the proposed topologies.

282 citations


"Maximum Power Point Tracking for Ph..." refers background in this paper

  • ...The SC based boost multilevel inverters [13]–[18] are becoming more popular because of their simple control, absence of magnetics and capacitor voltage balance circuitry, high conversion gain and reduced filter size....

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Journal ArticleDOI
Abstract: In this paper, initially a new dc/dc converter is proposed which can produce boosted multiple dc link voltages by using the novel switched-capacitor converter (SCC) and with reduced number of switches. In the proposed SCC, voltage of all capacitors is charged by binary asymmetrical pattern as self-balancing and without using any auxiliary circuits. The proposed SCC will boost the input dc power supply voltage without transformer by switching the capacitors in series and in parallel. Next, a new single phase switched-capacitor multilevel inverter (SCMLI) topology which uses the proposed SCC units as virtual dc links have been proposed. The proposed topologies reduce the number of power switches, diodes, isolated dc power supplies, size, and the cost of the system in comparison with conventional similar topologies. For example, by contribution of proposed SCMLI structure, 49 and 137 output voltage levels are made by only 14 and18 power switches and 3 and 4 isolated dc power supplies, respectively. To confirm the performance of proposed topology, various simulation results by PSCAD/EMTDC software and experimental tests are given.

144 citations


"Maximum Power Point Tracking for Ph..." refers background in this paper

  • ...Each capacitors are made to charge at regular intervals eliminates the requirement of charge balancing circuits [16]....

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Journal ArticleDOI
B.S. Prasad1, Sachin Jain1, Vivek Agarwal1Institutions (1)
Abstract: A new single-stage grid-connected inverter, suitable for distributed generation applications, is proposed. The inverter is universal in the sense that it can be switched between buck, boost, and buck--boost configurations by appropriately altering the pulse width modular (PWM) control. Discontinuous current mode (DCM) operation is implemented to facilitate shuffling between configurations during the converter operation. Such flexibility ensures maximum benefit of the buck, boost, and the buck--boost operations (e.g., low device stresses, higher efficiency, higher boosting capability, etc.). The PWM is achieved by comparing a high frequency carrier (triangular) waveform with a suitable reference waveform, which is not necessarily sinusoidal, but has a shape specific to the individual configuration and is derived by equating the power fed into the grid with that extracted from the source during each switching cycle. The values of the components (inductors and capacitors) need to be optimized so that DCM is maintained and the required amount of energy is transferred to the grid in all the three configurations during their respective operation. All the design expressions have been derived. A salient feature of this inverter is its compatibility with various types of sources (PV array, fuel cell, etc.) with varying voltage levels and control requirements. Being single-stage, the proposed topology offers additional advantages like modularity, compactness, and low cost. All the details of simulation and experimental work are presented.

138 citations


"Maximum Power Point Tracking for Ph..." refers background in this paper

  • ...Various single stage boost converter topologies for both dc and ac loads are presented in literature [1]– [3]....

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Journal ArticleDOI
TL;DR: An OCC-based grid-connected single-stage PV system is proposed in this paper which does not require to sense the grid voltage and requires less number of sensors as compared to that required in the earlier reported scheme.
Abstract: Reforms in the electricity sector along with various renewable-energy-promotion policies have increased the importance of small grid-connected photovoltaic (PV) systems utilizing single-stage single-phase inverters. Ruggedness, reliability, and cost effectiveness are the desirable characteristics of such inverters used in distributed low-power applications. Schemes based on one-cycle control (OCC) which do not require the service of a phase-locked loop for interfacing the inverter to the grid are increasingly being employed for such applications. However, the OCC-based schemes reported earlier require sensing of the grid voltage which somewhat offsets one of the inherent strengths of OCC-based systems. In an effort to overcome the aforementioned limitation, an OCC-based grid-connected single-stage PV system is proposed in this paper which does not require to sense the grid voltage. Further, it requires less number of sensors (two) as compared to that required (four) in the earlier reported scheme for the implementation of the core controller comprising of OCC and maximum-power-point-tracking blocks. The viability of the proposed scheme is confirmed by performing simulation and experimental validation.

112 citations


"Maximum Power Point Tracking for Ph..." refers background in this paper

  • ...Various single stage boost converter topologies for both dc and ac loads are presented in literature [1]– [3]....

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  • ...INTRODUCTION Single stage photovoltaic (PV) based converter systems are widely used because of their lower cost and higher efficiency [1]....

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