Analysis of an interleaved control scheme employed in split source inverter based grid‐tied photovoltaic systems

Abstract

In conventional grid‐tied renewable energy applications, the dc–dc converter is inevitable. An increased cost, size, and reduced efficiency are the demerits of incorporating a dc–dc converter. A recently introduced split source inverter (SSI) is capable to perform both dc–dc as well as dcac at a time. The main attractive controllable feature of SSI is its modulation index. By utilizing this parameter, an interleaved control structure is proposed for the SSI in grid‐tied photovoltaic applications. The main objectives of the work are to track peak power and to maintain a stabilized voltage across the dc‐link capacitor at a variable load and grid disturbances. The proposed peak power controller performs two important actions: (i) the peak power is traced at all irradiance and (ii) generates a duty cycle to enhance the dc‐link capacitor voltage. The proposed scheme is essentially investigated with simulation. To validate experimentally, a 1 KW photovoltaic system is integrated into a grid‐tied 10 kVA SSI prototype. A Xilinx based Spartan field‐programmable gate array (FPGA) is used to provide a control algorithm for the SSI. Few case studies at different conditions are performed and investigated. Experimental and simulation results are presented to prove the robustness of the control strategy.

Simplified three‐phase split‐source inverter for PV system application controlled via model‐predictive control

“…While the SSI deals with four possible switching states only, if Q 7 is switched OFF. The voltage vectors can be obtained in αβ frame from (21). For each of voltage vector, the output voltages (v c (k + 1)) can be predicted (17) for the following instance.…”

“…So, the dynamic equation of the energy for the DC‐side capacitor is (23). The SSI and filter power losses are neglected 21,22 …”

“…17 The single-phase SSI for PV application is introduced in Elthokaby et al 18 While the performance of the three-phase SSI is examined with standalone PV systems via regulated modified space vector modulation PWM control. 19 Grid-connected PV system based on SSI has been introduced in previous studies [20][21][22] with different control techniques. In Abdelhakim et al 20 and Nannam et al, 21 the control system depends on PWM techniques, while in de Azevedo Borges and Grigoletto 22 the control system is based on MPC.…”

“…19 Grid-connected PV system based on SSI has been introduced in previous studies [20][21][22] with different control techniques. In Abdelhakim et al 20 and Nannam et al, 21 the control system depends on PWM techniques, while in de Azevedo Borges and Grigoletto 22 the control system is based on MPC. In Nannam et al, 23 the behavior of the three-phase SSI with the wind system is investigated as a grid-connected system, controlled via the PWM technique.…”