Nonlinear control for power converters injecting the maximum power from PV arrays

Henriquez, Pablo; Cuevas, Saul; Rohten, Jaime; Araya, Sergio Salazar; Esparza, Vladimir; Sanhueza, Gustavo; Melín, Pedro

doi:10.1109/ica-acca.2016.7778451

Cited by 5 publications

(4 citation statements)

References 6 publications

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“…Once the nonlinear feedback is defined, the current is d and is q can be controlled independently, considering no coupling between them and no interaction with disturbances as the grid voltage, the solar power variation, among others [32]. To track the current reference, it is recommended to include a PI controller to mitigate the effects of minors errors in the nonlinear feedback of ( 20) and ( 21) such as deviation on the parameters, as stated in [30], and non-modeled dynamics, where the PI defines the new input u dq as:…”

Section: ) Current Controlmentioning

confidence: 99%

A Novel Global Maximum Power Point Tracking Method Based on Measurement Cells

Morales¹,

Rohten²,

Garbarino³

et al. 2022

IEEE Access

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Solar power generation has become a solution to mitigate the severe effects on the everyday higher prices of fossil fuels. Additionally, renewable energies operation -as solar-results in a non-polluting way to supply energy, being of special interest into highly contaminated cities and/or countries. The solar energy efficiency injection system is known to be high and mainly due to the power converters effectiveness, which is over of 95% for low and medium voltage. However, this efficiency is reduced when the solar array is partially shaded because traditional maximum power point tracking (MPPT) algorithms are not able to find the maximum power point (MPP) under irregular radiation. This work presents a new algorithm to find the global MPP (GMPP) based upon two MPPTs algorithms used regularly in uniform solar condition (USC), these are the Measuring Cell (MC) and the Perturb and Observe (P&O) methods. The MC ensures to find the surroundings of every local MPP (LMPP) faster and then choose among them the surroundings of the GMPP. Once the surroundings of GMPP are found, the P&O is used to get closer to the GMPP but reducing the DC voltage oscillation to zero hence overcoming the main issue of the P&O. Thus, the proposed algorithm finds the GMPP in two main steps and eliminates the oscillations around the GMPP in steady state, despite the utilization of the P&O. The algorithm is detailed mathematically, illustrated by means of a block diagram, and validated in simulated and experimental results.

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Section: ) Current Controlmentioning

confidence: 99%

A Novel Global Maximum Power Point Tracking Method Based on Measurement Cells

Morales¹,

Rohten²,

Garbarino³

et al. 2022

IEEE Access

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“…A two-stage three-phase inverter based on linearization technique to inject maximum power into the grid from the PV array is presented in [33]. However, the linearization technique could lead to stability issues when the parameters of the system vary, or the operating conditions change.…”

Section: List Of Tablesmentioning

confidence: 99%

“…The nonlinear controller is designed to track the MPP operation of the PV array and to control the active and reactive power to obtain unity power factor on the grid side. Thus, it is not necessary the use of a DC-DC converter as is required in other works based on nonlinear control as in [24] and [33]. The block diagram of the proposed controller is shown in Figure 4.1.…”

Section: Synchronous Reference Frame Control For Three-phase Systemsmentioning

confidence: 99%

“…For three-phase grid-connected PV systems based on nonlinear control, some works obtain the reference current through a DC-DC converter as in [24] and [33], thus using the two-stage scheme. For a single-stage scheme, the reference current is directly A common and general approach for studying the stability of nonlinear control systems is the Lyapunov stability theory.…”

Section: Design Of the D-axis Reference Current Trajectorymentioning

confidence: 99%

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Grid-connected photovoltaic systems based on nonlinear control.

Rivera¹

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Solar energy, considered as abundant and clean renewable energy source, has been utilized for a variety of applications such as generation of electricity for low and medium power. Nowadays, due to the high-scale penetration of photovoltaic systems, reliable and efficient grid-connected photovoltaic (PV) systems using the advances of power electronics and control system technology are desirable. Thus, single-stage gridconnected photovoltaic systems, have gained attention, especially in low voltage applications. However, PV systems exhibit nonlinear behavior due to the intrinsic features of the PV cell and nonlinear switching functions of the inverter that could negatively affect the performance of the system if they are not adequately compensated for. In this dissertation, using the general structure for the synchronous dq0 frame, a single-stage three-phase grid-connected photovoltaic inverter with a nonlinear control strategy is developed to track the maximum power regardless of the atmospheric conditions and to control the active and reactive power without the necessity of an additional power converter. A novel trajectory of the reference current is obtained online taking into account the dynamics of the DC link capacitor and the switching function of the inverter. v Furthermore, due to increased penetration of low-power single-phase PV systems in residential applications, a single-stage single-phase grid-connected PV system with a nonlinear control strategy is proposed in this dissertation. Unlike to the three-phase system, the single-phase system includes a novel method to mitigate the double linefrequency current ripple of the PV array, which is the major drawback of the single-phase PV inverter. Moreover, based on the preceded work, the nonlinear controller is combined with adaptive control to estimate the unknown disturbances that physically could appear in the circuit and affect the performance of the system. Additionally, in this study, the stability of the system and boundedness of signals of the closed-loop system are demonstrated by Lyapunov stability analysis for both the three-phase system and the single-phase system respectively. Simulation results show the effectiveness and robustness of the proposed controllers to track the maximum power and to control the active and reactive power to sudden changes in the atmospheric conditions and changes in the load.

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