Modeling and Simulation of Closed Loop Controlled Parallel Cascaded Buck Boost Converter Inverter Based Solar System

Abstract

This Work deals with design, modeling and simulation of parallel cascaded buck boost converter inverter based closed loop controlled solar system. Two buck boost converters are cascaded in parallel to reduce the ripple in DC output. The DC from the solar cell is stepped up using boost converter. The output of the boost converter is converted to 50Hz AC using single phase full bridge inverter. The simulation results of open loop and closed loop systems are compared. This paper has presented a simulink model for closed loop controlled solar system. Parallel cascaded buck boost converter is proposed for solar system. Keyword: Bidirectional inverter INTRODUCTIONA DC-DC converter is a vital part of alternative and renewable energy conversion, portable devices, and many industrial processes. It is essentially used to achieve a regulated DC voltage from an unregulated DC source which may be the output of a rectifier or a battery or a solar cell etc. Nevertheless, the variation in the source is significant, mainly because of the variation in the line voltage, running out of a battery etc., but within a specified limit. Taking all these into account, the objective is to regulate the voltage at a desired value while delivering to a widely varying load. A DC-DC switching regulator is known to be superior over a linear regulator mainly because of its better efficiency and higher current-driving capability. There are various topologies in the context of DC-DC converters the buck-boost converter are widely used. The basic circuit of buck-boost converter is shown in Figure 1. The output voltage of a DC-DC converter is controlled by operating it in the closed loop, and altering its MOSFET (switch) gate signal accordingly. It is basically governed by a switching logic, thus constituting a set of subsystems depending upon the status (on-off) of the switch. In the well known pulse width modulation (PWM) technique, the control is accomplished by varying the duty ratio of an external fixed frequency clock through one or more feedback loops, whenever any parameter varies. PI controllers are the most widely-used type of controller for industrial applications. They are structurally simple and exhibit robust performance over a wide range of operating conditions. In the absence of the complete knowledge of the process, these types of controllers are the most efficient choices. Power-Management strategies for a grid connected PV-FC hybrid system [1]. Optimized wind energy harvesting system using resistance emulator and active rectifier for wireless sensor nodes [2]. A hybrid

An Overview of Bidirectional AC-DC Grid Connected Converter Topologies for Low Voltage Battery Integration

“…Although in the article is not mention efficiency of the converter, can be predicted that it can reach high value. A similar topology can be applied to the 3 phase AC system with high frequency AC link [16], [17] and usage of bidirectional switches. [15] In [18] it is proposed topology with a current source inverter (CSI) (Figure 6) to interface the grid.…”

Frequency synchronization of a single-phase grid-connected DC/AC inverter using a double integration method

“…The traditional variable frequency oscillator is replaced in digital with a shift of the angle at each sampling moment. PLL systems react also on harmonics, but it happens by a frequency modulation [7]. In PLL systems, the loop gain should be high at synchronizing, and slow in a normal operation.…”

“…The single-phase inverter voltage output has only one and a second signal would be needed in order to construct a second phase of 90 shift [7]. The more common used method is the PLL control; however, it has a number of drawbacks.…”

The Improvement of Solar Cell Output Power Using Cooling and Reflection from Mirror

“…The current of solar cell is given by Equation 4 where I PH is current generated by incoming light, I S is saturation current, q is electron charge 1.6x10 -19 C, k is Boltzman constant 1.38x10 -23 J/K, T is temperature [21]. It is important to obtain solar energy near the maximum power point [22], [23].…”