A high efficiency PV micro-inverter with grid support functions

Todorovic, Maja Harfman; Tao, Fengfeng; Agamy, Mohammed; Dong, Dezun; Liu, X.; Garces, Luis; Zhou, Rui; Delgado, E.; Marabell, Donald; Stephens, Charles; Steigerwald, R.L.

doi:10.1109/ecce.2014.6953979

Cited by 20 publications

(8 citation statements)

References 9 publications

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“…The PPC configuration based on a step-up operation has been already addressed in several works for different applications [11][12][13][14][15]. Focusing on PPC for microinverters PV applications, the most relevant works are found in [16][17][18][19]. They present an improvement in the conversion efficiency, which is commonly a problem in microinverters due to the high voltage elevation required for the grid-connection.…”

Section: Step-down Partial Power Converters For Pv Systemsmentioning

confidence: 99%

Step-Down Partial Power DC-DC Converters for Two-Stage Photovoltaic String Inverters

et al. 2019

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Photovoltaic (PV) systems composed by two energy conversion stages are attractive from an operation point of view. This is because the maximum power point tracking (MPPT) range is extended, due to the voltage decoupling between the PV system and the dc-link. Nevertheless, the additional dc-dc conversion stage increases the volume, cost and power converter losses. Therefore, central inverters based on a single-stage converter, have been a mainstream solution to interface large-scale PV arrays composed of several strings connected in parallel made by the series connections of PV modules. The concept of partial power converters (PPC), previously reported as a voltage step-up stage, has not addressed in depth for all types of PV applications. In this work, a PPC performing voltage step-down operation is proposed and analyzed. This concept is interesting from the industry point of view, since with the new isolation standards of PV modules are reaching 1500 V, increasing both the size of the string and dc-link voltage for single-stage inverters. Since grid connection remains typically at 690 V, larger strings impose more demanding operation for single-stage central inverters (required to operate at lower modulation indexes and demand higher blocking voltage devices), making the proposed step-down PPC an attractive solution. Theoretical analysis and an experimental test-bench was built in order to validate the PPC concept, the control performance and the improvement of the conversion efficiency. The experimental results corroborate the benefits of using a PPC, in terms of increasing the system efficiency by reducing the processed power of the converter, while not affecting the system performance.

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Section: Step-down Partial Power Converters For Pv Systemsmentioning

confidence: 99%

Step-Down Partial Power DC-DC Converters for Two-Stage Photovoltaic String Inverters

et al. 2019

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“…Its maximum efficiency is 96% at 50% rated load. Though the maximum efficiency is 1% higher in [23], the merits of the proposed MI in this study are the formulation of an improved INC MPPT to The efficiency values of the MI without and with the proposed 2nd ripple voltage cancelation control are 94.8% and 95% respectively. Under full-load conditions, the efficiency values are 93.9% and 94.2% respectively.…”

Section: Mppt Controller Designmentioning

confidence: 99%

“…Its maximum efficiency is 96% at 50% rated load. Though the maximum efficiency is 1% higher in [23], the merits of the proposed …”

Section: Mppt Controller Designmentioning

confidence: 99%

“…Its maximum efficiency is 96% at 50% rated load. Though the maximum efficiency is 1% higher in [23], the merits of the proposed MI in this study are the formulation of an improved INC MPPT to Figure 14 presents the power conversion efficiency of the MI without and with 2nd ripple voltage cancelation control. Maximum efficiency is achieved at 60% load under both test conditions.…”

Section: Mppt Controller Designmentioning

confidence: 99%

“…This is a clear demonstration that the proposed 2nd ripple voltage cancelation control is able to improve the power conversion efficiency of the MI. In [23], a MI composed of an input partial power processing resonant converter and an interleaved DC-AC inverter stage was proposed. Its maximum efficiency is 96% at 50% rated load.…”

Section: Mppt Controller Designmentioning

confidence: 99%

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Modeling and Controller Design of PV Micro Inverter without Using Electrolytic Capacitors and Input Current Sensors

2016

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This paper outlines the modeling and controller design of a novel two-stage photovoltaic (PV) micro inverter (MI) that eliminates the need for an electrolytic capacitor (E-cap) and input current sensor. The proposed MI uses an active-clamped current-fed push-pull DC-DC converter, cascaded with a full-bridge inverter. Three strategies are proposed to cope with the inherent limitations of a two-stage PV MI: (i) high-speed DC bus voltage regulation using an integrator to deal with the 2nd harmonic voltage ripples found in single-phase systems; (ii) inclusion of a small film capacitor in the DC bus to achieve ripple-free PV voltage; (iii) improved incremental conductance (INC) maximum power point tracking (MPPT) without the need for current sensing by the PV module. Simulation and experimental results demonstrate the efficacy of the proposed system.

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A low-cost solar micro-inverter with soft-switching capability utilizing circulating current

Liu

Agamy

Dong

et al. 2016

2016 IEEE Applied Power Electronics Conference and Exposition (APEC)

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A high efficiency PV micro-inverter with grid support functions

Cited by 20 publications

References 9 publications

Step-Down Partial Power DC-DC Converters for Two-Stage Photovoltaic String Inverters

Step-Down Partial Power DC-DC Converters for Two-Stage Photovoltaic String Inverters

Modeling and Controller Design of PV Micro Inverter without Using Electrolytic Capacitors and Input Current Sensors

A low-cost solar micro-inverter with soft-switching capability utilizing circulating current

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