A hybrid five‐level inverter configuration with improved reliability and reduced number of components

An improved carrier‐based pulse‐width‐modulation (CBPWM) technique for a three‐level (3L) F‐type neutral point‐clamped (FNPC) inverter is presented in this paper. By using the proposed modulation scheme, the DC‐link capacitor voltage at the neutral point is balanced. For manufacturers, reliability is one of the major concerns for all power electronics devices and parts. This paper proposes an extensive reliability analysis of the 3L‐FNPC inverter. Considering the mean time to failure (MTTF) of each device, the reliability of the 3L‐FNPC inverter is analyzed in this present work by using two different methods, which are the approximate method and the exact method. To compute the failure rate of the equipment, only the number of components is considered in the approximate method. Alternatively, exact methods are utilized to evaluate the reliability of a system by knowing the different stress levels and various operating environments of a specific system. Because of the strong correlation between device failure and temperature stress factors, power loss analysis is used in the exact method. The MATLAB Simulink environment is used to determine the power loss of the switching devices. A solar off‐grid photovoltaic (PV) system is considered for reliability testing. Experimental mission profile data are used to estimate the lifetime of the 3L‐FNPC inverter by applying the rainflow counting algorithm, the Coffin‐Manson model, and Miner's rule. The competitiveness, effectiveness, and reliability of the 3L‐FNPC inverter with the proposed modulation technique are validated using a hardware prototype.

Section: Approximate Methodsmentioning

confidence: 89%

Section: Exact Methodsmentioning

confidence: 99%

Section: Reliability Modeling Of F‐type Invertermentioning

confidence: 99%

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Reliability evaluation of carrier‐based pulse width modulated three‐level F‐type neutral point clamped inverter with power loss analysis

Roy

Kurre

Nannam

et al. 2023

“…All the carrier signals have same phase and frequency. If A ref and A cr denote the amplitude of reference signal and carrier signal, respectively, then modulation index (M) can be defined as in (6).…”

Section: Pulse Width Modulation Schemementioning

confidence: 99%

“…The switched-capacitor (SC)-based MLIs have the boosting feature, which is achieved by the charging and discharging of the capacitors. Numerous works on SC-MLIs are present having different boosting values [4][5][6] The latest development is the common ground (CG)-based SC-MLIs, which are useful in PV applications. This is due to the reason that they eliminate the leakage current problem, which occurs due to the parasitic capacitance between panel and grid.…”

Section: Introductionmentioning

confidence: 99%

A nine‐level common ground multilevel inverter (9L‐CGMLI) with reduced components and boosting ability

Sarwer

Anwar

Sarwar

2023

SummaryThis paper introduces a common ground (CG) nine‐level switched‐capacitor (SC)‐based multilevel inverter (MLI) with dual boosting feature. The proposed circuit possess 11 switches, 2 diodes, and 3 capacitors. A simple level‐shifted modulation method has been used to generate the switching signals. The key feature of the proposed circuit is the presence of common ground between the input and output. The CG configuration eliminates the leakage current problem encountered in photovoltaic (PV) applications, which means the proposed circuit is suitable for use in PV applications. Moreover, the circuit also possesses reduced overall components and voltage stress on switches. At the same time, the dual boosting feature is another salient feature of the proposed MLI. This means the input voltage is stepped up two times and we get boosted/increased voltage at the output. The various simulation and experimental conditions have been tried to test the circuit under different load situations. Moreover, the loss analysis using PLECS software tool has been done to get information about the circuit losses. The results are shown and explained in the concerned sections of the paper. A quantitative comparison, based on different parameters, has been provided with other nine‐level MLIs.

A single‐phase seven‐level buck‐boost common ground transformerless inverter for grid‐connected photovoltaic system

Agrawal,

Rage,

Sahoo

et al. 2023

Transformerless inverters have recently gained attention in view of their economic benefits and compactness for photovoltaic (PV) systems. However, the limited voltage regulation and common‐mode (CM) leakage current are major concerns in conventional transformerless PV inverters. This paper presents a single‐phase seven‐level buck‐boost common ground transformerless inverter (SLB2CGTLI) to achieve a wide range of output voltages and zero leakage current without any additional stages, respectively. The proposed converter utilizes switched capacitor (SC) cell to buck‐boost the input DC voltage and generates seven‐level voltage at the output terminals. A simple reconfiguration strategy is adopted in the switched capacitor cell to maintain the charge‐second balance across the capacitors. Moreover, the common ground between the AC grid neutral and the PV panel's negative terminal mitigates the leakage current completely. The theoretical steady state analysis for both buck and boost mode is presented and verified with simulation using MATLAB Simulink. The performance of the proposed inverter is analyzed and validated with experimental results by developing a laboratory prototype. Further, the dynamic response of the proposed converter is carried out using OP4510 real‐time simulator for the grid‐connected PV application.