Parasitic Effects on the Performance of DC-DC SEPIC in Photovoltaic Maximum Power Point Tracking Applications

Abstract

<p class="MsoNormal"> <span lang="EN-US">This paper presents an analysis of the effect of parasitic resistances on the performance of DC-DC Single Ended Pri</span><span lang="EN-US">- </span><span lang="EN-US">mary Inductor Converter (SEPIC) in photovoltaic maximum power point tracking (MPPT) applications. The energy storage elements incorporated in the SEPIC converter possess parasitic resistances. Although ideal components signif</span><span lang="EN-US">i</span><span lang="EN-US">cantly simplifies model development, but neglecting the parasitic effects in models may sometimes lead to failure in predicting first scale stability and actual performance. Therefore, the effects of parasitics have been taken into consid</span><span lang="EN-US">eration for improving the model accuracy, stability, robustness and dynamic performance analysis of the converter. De</span><span lang="EN-US">tail mathematical model of SEPIC converter including inductive parasitic has been developed. T</span><span lang="EN-AU">he performance of the converter in tracking MPP at different irradiance levels has been analyzed for variation in parasitic resistance. </span><span lang="EN-US">The con</span><span lang="EN-US">verter efficiency has been found above 83% for insolation level of 600 W/m² when the parasitic resistance in the energy storage element has been ignored. However, as the parasitic resistance of both of the inductor has increased to 1 ohm, a fraction of the power managed by the converter has dissipated; as a result the efficiency of the converter has reduced to 78% for the same insolation profile. Although the increasing value of the parasitic has assisted the converter to con</span><span lang="EN-US">verge quickly to reach the maximum power point. </span><span lang="EN-US">Furthermore</span><span lang="EN-US"> it has also been observed that the peak to peak load current ripple is reduced. The obtained simulation results have validated the competent of the MPPT converter model.</span><span lang="EN-US"><o:p></o:p></span> </p

Single Ended Primary Inductor Converter reliance of efficiency on switching frequency for use in MPPT application

“…This can be seen in figure 10 which is a thermal image of the SEPIC, with the MOSFET on the right and diode on the left. Behind the diode you can also see the inductors have heated above ambient temperature, the inductor's resistance increases with the increase in duty cycle as outlined in [3]. This is another contributing factor to the drop in efficiency at high duty cycle.…”

“…The maximum power point of the PV is dynamic, and so must be tracked using an MPPT. An MPPT consists of a DC/DC converter which forces the PV to operate at its maximum power point by varying the load line accordingly [3]. The converter's pulse width modulation (PWM) duty cycle is controlled by an algorithm that tracks the PV module's maximum power point.…”

MPPT oscillations minimization in PV system by controlling non-linear dynamics in SEPIC DC-DC converter

“…The various types of DC-DC converters [9][10][11][12] such as buck, boost, buck boost, Cuk and SEPIC are implemented in PV system by considering suitability factors such as cost, efficiency, maximum power flow, ease of drive system, Positive output voltage, system stability and concluded that SEPIC converter is commonly used in PV system to track maximum power from PV panel. Higher order converter such as SEPIC and Cuk are widely used for MPPT charge controller because of their excellent steady state performance, isolation, over current limit protection [13][14][15][16][17][18][19][20][21]. Quamruzzaman [17] has argued that the PV current with less ripple and improved dynamic response can be achieved by SEPIC converter also proved that high input current ripple content of the converter reduces the average value of current which may leads to wrong true MPP tracking.…”

A Simplified Design and Modeling of Boost Converter for Photovoltaic Sytem

“…Among all this methods P and O technique is simple and most widely used. The Inc method operates more successfully during the changing weather conditions but at the same time the complexity of the circuit also increases [7][8][9][10]. The other methods are also used depending on their computational time and system requirement.…”