Faculty Publications
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Item Efficient global peak tracking of PV system under mismatching conditions using searching technique and bisection method(Institute of Electrical and Electronics Engineers Inc., 2018) Ramana, V.V.; Mudlapur, A.; Damodaran, R.; Balasubramanian, B.; Mishra, S.Rapidly increasing energy demand is leading to increase in installation of photovoltaic (PV) plants across the globe. The PV modules are subjected to various conditions like shading, soiling and degradation because of which the performance of PV panels deteriorates. This will affect the characteristics of PV module which may lead to several stairs in I-V curves and several peaks in P-V curve. In this paper the various causes of occurrences of mismatching conditions are analyzed. An efficient two stage algorithm that tracks global maximum power point (GMPP) accurately under such mismatching conditions is proposed in the paper. In the first stage, a simple searching technique and bisection method are used to bring the operating point to the proximity of global maximum. In the second stage, hill climbing method maintains the operating point at global peak. MATLAB Simulations and experimental verifications are performed for validating the proposed approach. © 2018 IEEE.Item Experimental investigation of the effectiveness of the LC filter in PV fed induction motor water pumping systems with different type of inductors(Institute of Electrical and Electronics Engineers Inc., 2018) Mudlapur, A.; Subrahmanya Adiga, P.; Anusha, R.; Balasubramanian, B.This paper presents the experimental study of the effectiveness of the LC filter in PV fed water pumping systems. This study is very important in water pumping applications where prolonged running conditions is a major concern. LC filters are connected at the terminals of the inverter to avoid transient over voltages across the induction machine. The conventional LC filter with lumped gap inductor is studied initially. The temperature of the filter inductor is monitored to study its behaviour. It is inferred that the inductor temperature increases drastically due to the high winding losses and therefore may lead to system failure when run for longer duration. The inductor is replaced with uniformly distributed(powdered) core and low cost discretely distributed gap core so as to minimize the losses. Comparative study between the conventional and proposed inductors is carried out. It is inferred that discretely distributed gap inductors are a better choice over powdered core inductors. The experimentation is carried out on a 3-HP induction motor and results with lumped gap and discretely distributed gap inductors are presented along with their thermal profiles. Results show that, the discrete distributed gap inductor is the cost effective solution for the LC filter failures in water pumping applications. © 2018 IEEE.Item Modified Hysteresis Current Control for Single Phase Solar Grid-tie Z-Source Inverter(Institute of Electrical and Electronics Engineers Inc., 2018) Damodaran, R.; Balasubramanian, B.; Mudlapur, A.; Ramana, V.V.; Mishra, S.This paper proposes a simple novel technique to determine the shoot-through states in a hysteresis controlled solar grid connected single phase Z-source inverter (ZSI). The ZSI along with the proposed controller exhibits high efficiency due to the single stage conversion. Fast and robust dynamic response can be obtained by using hysteresis control. Hence the proposed control for ZSI is ideal for grid integration of photovoltaic sources. The error current is used to determine shoot-through states based on calculation of current limits as a function of the boost ratio and modulation index. The maximum boost ratio, that can be obtained by the proposed control without causing low frequency ripples in Z-source network, is expressed as a function of modulation index. To verify the analysis, simulations are performed for input and grid voltage variations using MATLAB-Simulink platform. © 2018 IEEE.Item A Novel Back to Back Inverter Configuration for Solar Water Pumping and Grid-Tie Application(Institute of Electrical and Electronics Engineers Inc., 2018) Parmar, J.V.; Reddy, S.K.; Swaminathan, B.; Mudlapur, A.; Balasubramanian, B.The use of photovoltaic (PV) as an energy source for pumping water is one of the most promising areas of photovoltaic applications. Solar water pumps are eco-friendly substitutes for diesel and grid powered water pumps. They provide better energy efficiency compared to diesel and grid powered pumps and also gives zero-carbon foot print during their use, promoting a healthy and a more sustainable environment. But PV being an unreliable source, prediction of water output is not possible. Further if photovoltaic array generates more power than the load requirement, the excess power is not harvested and when the demand is not met sufficient water is not pumped out. To mitigate this problem this paper presents a back to back voltage source converter (VSC) configuration increasing reliability, robustness and efficiency of the entire system. A new control strategy for back to back VSC for switching between grid-tie and active power factor correction (APFC) mode based on the natural power balance is presented to optimize energy utilisation and ensure maximum water output at all times. Detailed simulation studies are carried out using MATLAB/Simulink to verify the effectiveness of proposed scheme. © 2018 IEEE.Item A Novel AC Current Sensorless Hysteresis Control for Grid-Tie Inverters(Institute of Electrical and Electronics Engineers Inc., 2020) Damodaran, R.; Mudlapur, A.; Ramana, V.V.; Balasubramanian, B.; Mishra, S.Amongst the modulation techniques used for grid-Tie inverters (GTIs), hysteresis current control (HCC) facilitates simple, stable and rugged control with improved dynamic response. However the variable switching frequency of HCC demands high precision AC current sensors (CS) which introduce noise in the power circuit in addition to measurement noise and delay. Therefore, this brief presents a hysteresis current control without AC current sensor based on switching instant computation for a two-level GTI. The proposed control strategy uses the DC link and instantaneous grid voltages to calculate the switching instants. The conventional methods of calculating switching instant of HCC can result in tracking errors. Hence the computations are modified in the proposed algorithm considering the effects of non-linearity in error current and dynamic variations due to supply and load changes. A single-phase GTI is simulated with the proposed control and the results are verified experimentally. The proposed method is observed to considerably reduce the computational time, DC shift and total harmonic distortion compared to the commonly used sensorless current control. © 2004-2012 IEEE.