Control Strategy of Flyback Microinverter With Hybrid Mode for PV AC Modules

Lee, Sungho; Cha, Woo-Jun; Kwon, Jung-Min; Kwon, Bong-Hwan

doi:10.1109/tie.2015.2481365

Cited by 40 publications

(23 citation statements)

References 20 publications

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“…= 0 shows that the harmonic component is equal to zero only for δ = 0 and δ = 1, therefore that harmonic component has the same sign in the range of interest 0 ≤ δ ≤ 1, i.e., always positive or always negative. The extremum value of the harmonic component occurs at δ = 0.5 as reported in (27), which is a maximum since the second derivative of the harmonic component is negative at δ = 0.5, this is confirmed in (28).…”

Section: Range Of Operation For the Phase Shift δsupporting

confidence: 62%

“…The main drawback of those solutions is the use of several inductors and capacitors, which reduce both power density and efficiency. Other approach consist of using converters with galvanic isolation [14,16,[23][24][25][26][27][28], where the main concerns are the voltage and current stress on the power devices and soft switching capability, but for a well-designed isolated converter, high efficiency and voltage-conversion-ratio are achievable with low stress on the switching devices [29].…”

Section: Introductionmentioning

confidence: 99%

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Design Method of Dual Active Bridge Converters for Photovoltaic Systems with High Voltage Gain

et al. 2020

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In this paper, a design method for a photovoltaic system based on a dual active bridge converter and a photovoltaic module is proposed. The method is supported by analytical results and theoretical predictions, which are confirmed with circuital simulations. The analytical development, the theoretical predictions, and the validation through circuital simulations, are the main contributions of the paper. The dual active bridge converter is selected due to its high efficiency, high input and output voltages range, and high voltage-conversion ratio, which enables the interface of low-voltage photovoltaic modules with a high-voltage dc bus, such as the input of a micro-inverter. To propose the design method, the circuital analysis of the dual active bridge converter is performed to describe the general waveforms derived from the circuit behavior. Then, the analysis of the dual active bridge converter, interacting with a photovoltaic module driven by a maximum power point tracking algorithm, is used to establish the mathematical expressions for the leakage inductor current, the photovoltaic current, and the range of operation for the phase shift. The design method also provides analytical equations for both the high-frequency transformer equivalent leakage inductor and the photovoltaic side capacitor. The design method is validated through detailed circuital simulations of the whole photovoltaic system, which confirm that the maximum power of the photovoltaic module can be extracted with a correct design of the dual active bridge converter. Also, the theoretical restrictions of the photovoltaic system, such as the photovoltaic voltage and power ripples, are fulfilled with errors lower than 2% with respect to the circuital simulations. Finally, the simulation results also demonstrate that the maximum power point for different environmental conditions is reached, optimizing the phase shift factor with a maximum power point tracking algorithm.

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Section: Range Of Operation For the Phase Shift δsupporting

confidence: 62%

Section: Introductionmentioning

confidence: 99%

Design Method of Dual Active Bridge Converters for Photovoltaic Systems with High Voltage Gain

et al. 2020

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“…The clamp capacitor C c and resonant inductor L r are resonant at the resonant mode III. This resonant time period can be approximated to the maximum turn-off time of the main switch, as expressed in (26). The clamp capacitance can be determined by (27), where the lowest duty ratio is shown as…”

Section: Active-clamp Capacitormentioning

confidence: 99%

Enhanced soft‐switching strategy for flyback‐based microinverter in PV power systems

Rakhshandeh

Hassan

Farhangi

et al. 2019

IET Renewable Power Generation

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Flyback topology has been widely used to construct modular power conversion for solar photovoltaic (PV) grid-tied systems, which creates a parallel interconnection infrastructure and is considered as the most straightforward way to cope with the harmful mismatch effects among PV modules. The challenge becomes the conversion efficiency and system reliability to be competitive with traditional system configurations. This study proposes a comprehensive solution to overcome the present problem, which optimally integrates the technology of resonant circuit, adaptive modulation scheme, and active clamping to enhance soft-switching capability and system efficiency. The effectiveness of theoretical analysis, circuit design, and modulation scheme is analysed by simulation and verified by experimental evaluation. The California Energy Commission efficiency is tested and shown as 97.4%.

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“…The three operating modes of the flyback inverter are the continuous conduction mode (CCM) [13][14][15][16], discontinuous conduction mode (DCM) [17][18][19][20] and boundary conduction mode (BCM) [21][22][23][24]. In BCM, the instantaneous demagnetisation of the transformer leads to a variable switching frequency.…”

Section: Introductionmentioning

confidence: 99%

Performance optimisation of the grid‐connected flyback inverter under improved hybrid conduction mode

Mohammadi

Izadfar

Eskandarian

2020

IET Renewable Power Generation

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In the unfolding-type interleaved two-switch flyback inverter (ILTFI) operating in discontinuous conduction mode (DCM), the hybrid control strategy combining the one-phase DCM and the two-phase DCM has a significant impact on improving the efficiency under all load conditions. In the situation where the marginal power of this control strategy is increased, the converter may enter CCM. Consequently, the converter cannot track the reference current and the output current quality is notably decreased. To tackle this issue, a novel hybrid control method is proposed which varies the switching frequency based on the output power. The proposed approach is immune to the loss analysis and power losses of the components. Hence, it is independent of components selection and their characteristics. In this case, the smooth transition between the one-phase and the two-phase operation modes is guaranteed without affecting the output power quality and the stability of the converter in DCM. The control complexity of the proposed scheme is low and the converter can be easily controlled in DCM. The performance of the flyback microinverter with the proposed hybrid control scheme is verified by the simulation and the experimental results together with the loss analysis.

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Control Strategy of Flyback Microinverter With Hybrid Mode for PV AC Modules

Cited by 40 publications

References 20 publications

Design Method of Dual Active Bridge Converters for Photovoltaic Systems with High Voltage Gain

Design Method of Dual Active Bridge Converters for Photovoltaic Systems with High Voltage Gain

Enhanced soft‐switching strategy for flyback‐based microinverter in PV power systems

Performance optimisation of the grid‐connected flyback inverter under improved hybrid conduction mode

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