PV Fed Grid Power Control by Discrete CUK Converter and SPWM Inverter Control Techniques

Abstract

In this paper the power supplied to the grid is regulated with the help of Discrete Sliding Mode Controlled (DSMC) CUK converter and Sinusoidal Pulse Width Modulation (SPWM) topology controlled 3-phase Inverter. The CUK converter is used in the input side to Buck or Boost the PV (Photo Voltaic) array voltage to the required value of the 3 -phase Inverter. Natural isolation of source and load is obtained in the CUK converter with the help of capacitor energy transfer so that the ripple content is less in both load and source side. These CUK converters are operating in continuous current mode so that regulation of power from the solar panel is easy and efficient compared to Buck-Boost converters. In this paper DSMC CUK converter topology is implemented so that converter is feasible to incorporate with any digital controller with less hardware requirements, it has flexibility in control characteristics and guaranteed stability of highly fluctuating solar power under different climate conditions. The simulation model has battery back-up which is charged during high irradiation time and provides power to load during less irradiation climate conditions. The 3-phase Inverter is controlled by SPWM technique to reduce the switching losses of the Inverter so that the harmonics in the load side is less and it is easy to implement. So that the overall system is efficient, ease of implementation, robust and economical.

Real time hardware implementation of discrete sliding mode fuzzy controlled buck converter using digital signal processor

“…DSMFC for buck converter has been designed, which is software in loop with the hardware converter is shown in Figure 2. The input to the controller is inductor current and output voltage or capacitor voltage of the buck converter and output of the controller is the control signal [10]. The inputs and output are connected to the controller through universal serial bus (USB) cables.…”

Combined feed-forward control strategy for LCL-type grid-connected inverters

“…In order to increase the utilization of new energy sources and reduce energy losses, higher requirements are being placed on the performance of line network transmission. LCL-type grid-connected filter circuits are widely used in line grid transmission because of their strong suppression of current harmonics, but the circuit has a resonance point where the system can generate severe oscillations and the inclusion of LCL-type filter circuits can reduce the stability of the inverter system [2].…”