Interfacing renewable energy sources for maximum power transfer—Part II: Dynamics

Kolesnik, Sergei; Sitbon, Moshe; Gadelovits, Shlomo; Suntio, Teuvo; Kuperman, Alon

doi:10.1016/j.rser.2015.04.043

Cited by 19 publications

(5 citation statements)

References 55 publications

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“…Renewable energy sources possess the so-called soft source characteristics, requiring careful interfacing (i.e., maximum power point tracking, MPPT) to allow optimal utilization in terms of cost and reliability [1,2]. A generalized renewable energy conversion system is shown in Figure 1, consisting of a renewable energy generator (REG), an interfacing power converter (IPC), and a load.…”

Section: Introductionmentioning

confidence: 99%

Analytical Derivation of Electrical-Side Maximum Power Line for Wind Generators

Kolesnik

Kuperman

2017

Energies

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Abstract:In order to enhance the maximum power point tracking (MPPT) speed of solar generators, offline calculated maximum power line (MPL) is often used as a feed-forward signal added to the output of MPPT controller. MPL is nonlinear static electrical characteristic of renewable energy generators connecting all the maximum power points for given temperature. In this letter, electrical side MPL is derived for a typical wind turbine generator (WTG). It is shown that MPLs of solar and wind generators possess similar structure, supporting the similarity between the two energy conversion processes.

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Section: Introductionmentioning

confidence: 99%

Analytical Derivation of Electrical-Side Maximum Power Line for Wind Generators

Kolesnik

Kuperman

2017

Energies

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“…Consequently, matching generation and consumption levels Manuscript received 30 May, 2021; accepted 14 January, 2022. in isolated microgrids [8] are of primary importance [9]. Studies have shown that the properties of the source significantly influence the dynamics of the power converter [10]. One of the variables subject to significant variation due to different operating points is the dynamic resistance of PVG.…”

Section: Introductionmentioning

confidence: 99%

Analysis, Modeling, and Simulation of Adaptive Control Based on Dynamic Conductance Estimation of Photovoltaic Generator Interfaced Current-Mode Buck Converter

Malinkovich¹,

Lineykin

Sitbon

2022

ELEKTRON ELEKTROTECH

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In this paper, a novel adaptive control method is presented, aimed at robustifying the terminal voltage of the photovoltaic generator, interfaced by the current-mode-controlled buck DC-DC converter load, and based on conductance estimation. The photovoltaic generator, which is integrated into the buck converter and a battery storage unit, is continuously affected by the operating point of the system and environmental variables, thus presenting a nonlinear behavior. Furthermore, the development of small-signal equations reveals a potentially unstable condition when the system is used as a micro-grid with a battery storage unit. This study shows that when the nonlinear behavior of the photovoltaic generator is combined with a typical nominal controller, designed for a single nominal operating point and due to the possibility of an unstable condition, it forces the controller to operate mostly outside the nominal operating point. These conditions result in significantly varied closed-loop performance. In contrast, an almost perfect loop gain performance can be achieved when implementing an adaptive controller based on an online conductance estimation method. Applying estimator results and injecting its value in real-time into the inverse-based plant controller results in an adaptive controller. Therefore, the closed-loop performance of the system integrated with an adaptive controller achieves an almost nominal response throughout the operating range.

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“…Upon variation of one or both environmental variables, locations of MPP current and voltage-and hence power-change. Such a behavior calls for instantaneous maximum power point tracking (MPPT) in order to optimize PVG economical utilization [2].…”

Section: Introductionmentioning

confidence: 99%

Direct Fixed-Step Maximum Power Point Tracking Algorithms with Adaptive Perturbation Frequency

2019

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Owing to the good trade-off between implementation and performance, fixed-step direct maximum power point tracking techniques (e.g., perturb and observe and incremental conductance algorithms) have gained popularity over the years. In order to optimize their performance, perturbation frequency and perturbation step size are usually determined a priori. While the first mentioned design parameter is typically dictated by the worst-case settling time of the combined energy conversion system, the latter must be high enough to both differentiate the system response from that caused by irradiation variation and match the finite resolution of the analog-to-digital converter in case of digital implementation. Well-established design guidelines, however, aim to optimize steady-state algorithm performance while leaving transients nearly untreated. To improve transient behavior while keeping the steady-state operation unaltered, variable step direct maximum power point tracking algorithms based on adaptive perturbation step size were proposed. This paper proposes a concept of utilizing adaptive perturbation frequency rather than variable step size, based on recently revised guidelines for designing fixed-step direct maximum power point tracking techniques. Preliminary results demonstrate the superiority of the proposed method over adaptive perturbation step size operation during transients, without compromising the steady state performance.Energies 2019, 12, 399 2 of 16 between transient and steady-state operation [21]. In order to tackle this drawback, adjustable (or adaptive) step size versions of non-model-based algorithms have been proposed [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38], in which the step size is adjusted, typically in proportion to the derivative of PVG power with respect to control variable. Indeed, such algorithms demonstrate superiority over the fixed step versions, achieved at the expense of more complex implementation. It is interesting to note that the performance similarity of fixed step direct non-model-based algorithms versions have been revealed [39,40], while the equivalence of major variable step size MPPT algorithms has been demonstrated [41].Consider, without loss of generality, a photovoltaic energy conversion operating under a single-loop direct non-model based MPPT. For example, the interfacing power converter (IPC) duty cycle is the perturbed variable (see Figure 1a). A small perturbation ∆d is injected into the system every T p seconds. Following a T ∆ -lasting transient, the corresponding change in generated power is observed either at the PVG or load side (see Figure 1b), and the next perturbation polarity (in fixed step versions) and size (in variable step versions) is determined so that the operation point is driven towards the MPP. It was shown in References [13,21] that the maximum perturbation frequency (reciprocal of T p ) is limited by settling time of the generated power transient induced by the perturbation while the minimum perturbation step size dep...

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Interfacing renewable energy sources for maximum power transfer—Part II: Dynamics

Cited by 19 publications

References 55 publications

Analytical Derivation of Electrical-Side Maximum Power Line for Wind Generators

Analytical Derivation of Electrical-Side Maximum Power Line for Wind Generators

Analysis, Modeling, and Simulation of Adaptive Control Based on Dynamic Conductance Estimation of Photovoltaic Generator Interfaced Current-Mode Buck Converter

Direct Fixed-Step Maximum Power Point Tracking Algorithms with Adaptive Perturbation Frequency

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