Experimental investigation of the effectiveness of the LC filter in PV fed induction motor water pumping systems with different type of inductors

摘要

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.