Three‐phase tri‐state buck–boost integrated inverter for solar applications

Abstract

This study presents a three-phase tri-state buck-boost integrated inverter suitable for stand-alone and/or grid-connected photovoltaic (PV) energy applications. The usage of the special features of the tri-state operation coupled with a modified space vector modulation allows the inverter to present a remarkable degree of freedom for the controllers' design, that is, input and output can be independently controlled. As the input can be autonomously controlled, this converter is very attractive for interfacing renewable energy sources as PV panels, once the main duty cycle D 1 controls the maximum power point tracking and the second duty cycle D 2 is responsible to feed the output. It should be pointed out that there are no power electrolytic capacitors in this integrated inverter, which results in a major advantage for the structure working life and it is the first time in the literature that this inverter is used to feed power into the grid. Throughout this study the system is described, the modulation and control schemes are presented and interesting experimental results are available in order to confirm the outstanding features of this proposal.

Dynamic performance comparison involving grid‐connected PV systems operating with active power‐line conditioning and subjected to sudden solar irradiation changes

“…From Fig. 4b, the closed-loop TF of the DC-bus voltage control system is given by: (25) where K Pv and K Pv are the respective proportional and integral controller gains, respectively.…”

“…Commonly, the majority of PV systems are classified into single-or double-stage energy conversion systems [9,10,[22][23][24]. In single-stage systems, the PV array is coupled directly to the DCbus of the grid-tied inverter, which injects power into the grid while performing the MPPT [9,25]. For the double-stage systems, a DC-DC converter is placed between the PV array and the inverter to step-up the PV array voltage, while performing the MPPT [10,11].…”

An Efficient Grid-Connected Three-Phase Single-Stage Boost Current Source Inverter

“…However, this inverter provided a boost ratio of about 1.33 (at the line-line output voltage of 400V rms ) with a switching frequency of 7.5kHz, and high efficiency of the inverter was only possible without the boost capability. Brito et al (2015) presented a tri-state buck-boost integrated boost inverter, which is a two-stage inverter, made of a cascaded dc-dc converter with a SVPWM based CSI [20]. In their work, an overall efficiency of 90% was reported for a boost ratio of 1.27 (PV module output of ∼ 100V is boosted to a line-line output voltage of 127V rms ).…”

Comparative analysis of MPPT algorithms bio‐inspired by grey wolves employing a feed‐forward control loop in a three‐phase grid‐connected photovoltaic system

“…Accordingly, research and new investments involving solar energy have been of great importance to contribute to the increase and improvements of PV systems. [10][11][12][13][14].…”