International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 12 Issue: 11 | Nov 2025
p-ISSN: 2395-0072
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PERFORMANCE ANALYSIS OF DC SYSTEM USING RIPPLE ELIMINATOR TO IMPROVE POWER QUALITY BIBIFATHIMA S1, Smt.MAMATHA B N2 1Fourth Sem, MTech, UBDTCE, Davanagere 2Assistant Professor, BE ,M.Tech, (PHD)
---------------------------------------------------------------------***--------------------------------------------------------------------ripples could lead to an immoderate chemical reaction. Abstract - For dc systems, voltage/current ripples have
During the discharging mode, ripple currents drawn from a fuel cell can degrade the system efficiency significantly and even make it unstable. Generally, current ripples should be maintained less than 10% of the rated current for batteries. In order to reduce the ripple current and smooth the external voltage on batteries and fuel cells, bulky capacitors or ultra-capacitor are often connected in parallel with them. Large electrolytic capacitors are also often needed to level and smooth the DC-bus voltage of inverters and rectifiers. For volume critical and/or weight-critical applications, such as electrical vehicles and aircraft power systems, the volume and weight of electrolytic capacitors could be a serious problem. Because of limited lifetime of electrolytic capacitors, they are one of the most vulnerable components in power electronic systems. According to, more than half of faults of static converters are caused by degraded electrolytic capacitors. On the other hand, the presence of large voltage ripples is an essential factor that accelerates the degradation of electrolytic capacitors. It a damaged UPS inverter assembly, the damage was caused by the ageing electrolytic capacitors. This may cause a big disruption in critical loads, which in turn could lead to a huge cost. As a result, in order to enhance the reliability of power electronic systems, it is highly desirable to minimize the usage of electrolytic capacitors and it is very attractive if highlyreliable small capacitors like film capacitors could be used to achieve low-level voltage ripples. However, in applications involving bulky electrolytic capacitors, it is often inevitable to have a tradeoff between minimizing the total capacitance required and suppressing voltage ripples. Another design degree of freedom, normally through active control, needs to be introduced to break this deadlock. In principle, this power quality issue in DC systems stems from energy fluctuation, which can come from sources and/or loads of systems. Four main approaches have been developed in the literature to reduce or compensate energy fluctuation so that the voltage ripples can be reduced and the power quality in DC systems can be improved. One approach is to inject harmonic currents to suppress the fluctuations of the input energy by changing the control strategy for the existing power switches in the system. In, it was proposed to inject third harmonic component to the input current so as to reduce the DC-bus capacitor in LED drivers. The analysis in these proposed designs is based on the fact that decreased pulsating input power leads to decreased ripple power and capacitor volume
emerged as a major power quality concern that could significantly impair performance on both the source and load sides and raise reliability issues. A single-phase pulse width modulation-controlled rectifier is used as an example in this suggested design to examine how active control techniques can enhance the power quality of dc systems, lessen voltage ripples, and simultaneously use fewer electrolytic capacitors. The ratio of capacitance reduction is measured, and the idea of ripple eliminators—which has been recently suggested in the literature—is expanded upon. In order to actively divert the ripple current on the dc bus, this power quality issue is formulated as a control problem with such ripple eliminators. This proposed design's primary goal is to examine how sophisticated control techniques might enhance ripple eliminators' performance. For one potential implementation of ripple eliminators in the continuous current mode (CCM), an advanced controller based on repetitive control is suggested. Results from experiments are shown to confirm the strategy's efficacy in comparison to another ripple eliminator that operates in the discontinuous current mode. It has been demonstrated that the suggested instantaneous ripple-current diversion in CCM improves performance by almost four times. Key Words: Ripple Eliminator, AC to DC, IGBT.
1.INTRODUCTION Proliferated renewable energy systems greatly promote the development of DC distributed power system, which enjoys flexible system configurations, high efficiency, and high density power delivery capability. In such DC systems, ripple power is often not a major concern because a DC current is constant and there is not an issue of phase differences between voltages and currents. However, in many applications like hybrid electrical vehicles and wind power systems, rectifiers and inverters are commonly used and DC voltages are not ideal but have a significant amount of harmonic components. Because of the harmonic components the voltages and the resulting ripple currents, ripple power has become a major power quality issue in DC systems. For systems powered by photovoltaic panels, batteries and fuel cells, large ripple currents and ripple voltages could considerably reduce the lifetime and long-term reliability of photovoltaic panels, batteries and fuel cells. During the charging mode of a battery, an external voltage with large
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