Modeling and Control Design of the Symmetrical Interleaved Coupled-Inductor-Based Boost DC-DC Converter with Clamp Circuits

Abstract

The symmetrical input-interleaved high-gain DC-DC converters are suitable candidates to be used as the first stage in PV microinverters and as parallel-connected power optimizers. In both applications, they are responsible for boosting the PV module DC voltage to a higher value and executing the maximum power point tracking control. However, such converters have many state variables, some of them discontinuous, and many operation stages, which make the development of the small-signal model a challenging task. Therefore, the aim of this paper is to propose a reduced-order improved average method (ROIAM) to model the family member of converters that present characteristics such as symmetry, interleaved operation, and discontinuous state-space variables. ROIAM is applied to model for the first time in the literature the symmetrically-interleaved coupled inductor-based boost (SICIBB), leading to a fourth-order mathematical model (reduced-order model). The complete eighth-order mathematical model is developed as well to prove that the reduced-order model represents correctly the dynamic behavior of the SICIBB converter by employing only four state variables, reducing considerably the effort of the modeling. Based on the reduced-order proposed model, a closed-loop control is designed and tested in a 300-W prototype of the SICIBB converter.

Sintonia de Controlador PI Para Sistema Fotovoltaico Autônomo Através de Alocação de Polos com Conversor Buck

“…No lugar da conexão direta de ciclo de trabalho é mais adequado utilizar um controlador de malha fechada com um compensador linear. Além de reduzir as perdas e o estresse do conversor, a presença de um controlador de malha fechada reduz o tempo de acomodação do conversor e evita oscilações e sob elevações, tornando mais fácil o funcionamento [1,9].…”

A Novel Single-Switch High Step-Up DC–DC Converter with Three-Winding Coupled Inductor

“…The development of technologies to improve the performance of architectures with distributed maximum power point tacking (MPPT) are fundamental to raise grid-utilitydistributed generation systems from photovoltaic (PV) solar sources in large urban centers, mainly for residential applications. Although architectures with PV module-integrated converters (MICs) and parallel connected power optimizers have maximum power point tracking (MPPT) per PV module capability, these configurations are different: architectures with MICs, shown in Figure 1a, convert the PV module DC voltage directly to AC, since MICs are composed of two power conversion stages (DC-DC followed by DC-AC); on the other hand, in architectures with parallel-connected power optimizers, shown in Figure 1b, the output DC voltage of the power optimizer is converted into AC by a central inverter [1,2].…”

“…Furthermore, an outstandingly high duty cycle causes large conduction losses and reverse recovery problems. As a consequence, the conventional boost converter would not be adequate for high step-up voltage gain applications [2][3][4][5].…”

An Overview of Voltage Boosting Techniques and Step-Up DC-DC Converters Topologies for PV Applications

“…MICs can have either single-stage or two-stages conversion systems: single-stage MICs perform voltage boosting, MPPT and grid current control in a single DC-AC power conversion; two-stages MICs have a DC-DC stage to boost the PV module DC voltage (between 20 V-45 V) to a higher value (above 380 V, for instance) while tracking the PV module maximum power point, followed by a DC-AC stage, responsible to DC-link voltage regulation and the grid-tied functions [4]. The main drawback of single-stage MICs is that the double-line-frequency voltage ripples must be filtered by a bulky input electrolytic capacitors at the input side [5], which affects the stable implementation of MPPT algorithms and reducing the life span of the entire system whereas two-stages MICs employ proper control strategies alongside small electrolytic capacitors in both conversion stages to eliminate it [6].…”

“…Compared to architectures with central inverter, MICs are inherently safer because the DC energy is converted to AC right at the site of the PV module [7]. Hence, they operate at the same low-voltage AC power as the grid utility, which means there is no long-distance high voltage DC cables [4]. Besides, since MICs are mounted in a single PV module and operate independently, system with MICs keeps delivering energy to the grid if one or more MICs fail while if a system with a central inverter fails, the energy production stops completely.…”