Photovoltaic based Induction motor speed control Using SEPIC converter

Abstract

A simplified photovoltaic based Speed control of Induction motor (IM)using SEPIC converter is proposed . It Improves overall performance of the system .Solar PV system consists of two stages of power transformation .Initial stage maximum power is absorbed from the solar PV panel using MPPT algorithm .Maximum power in the solar panel depends on variation of  temperature,PV array voltage and isolation level. Solar PV output is fed to the SEPIC converter. Varying the duty ratio of the SEPI converter input voltage of the motor to be controlled. Next stage different Speed is achieved by changing the voltage of IM. Stability is attained with help of implementing PI controller in closed loop system .PI controller eliminates noise signals and increase the steady state accuracy. New proposed method has high voltage gain, low voltage and current ripple factor ,and constant Speed control  of IM .Existing water pumping system used with boost converter, it provides less efficiency, more ripple factor . Normally current and voltage ripples create harmonics, harmonics are reduced by connecting large capacitor or an LC  filter .It makes the system more complicate ,expensive and inefficient .New system with SEPI converter  overcome the drawbacks .Induction motor becomes more familiar due to its advantages like self starting torque, high power factor, simple in construction and low maintenance. In Agriculture pumping system used for irrigation purpose. This new PV based pumping system provides pollution free environment compared to diesel water pumping system.