MPPT control technique for solar powered direct torque control of induction motor drive with a robust speed and parameters adaptation scheme for water pumping

Abstract

This paper presents a novel robust model reference adaptive system (MRAS) technique for rotor speed estimation of direct torque control (DTC) of an induction motor drive used for solar PV powered water pumping. The maximum power point tracking (MPPT) of PV array is assured by a proposed P&O algorithm, which has improved tracking time without deviation during insolation change. Moreover, an additional loop is incorporated in the MPPT control, which provides an additional feature of derating the panel, which consequently controls the flow rate. The effect of parameter variation e.g. change in rotor resistance, stator resistance and the rotor time constant on the stability of overall system, is analysed and tested. The MRAS involves fluxes estimation and uses the same machine parameters which are involved in DTC. The elimination of speed sensor and parameters adaptation make the overall induction motor drive (IMD) suitable for such application. The stability of the system is assured by Lyapunov's stability criterion and the stability of parameters adaptation is shown by Bode plot and well-known Popov's stability criterion. Therefore, the reduced sensors (voltage and current sensors) based proposed system with deviation-free MPPT technique and with flow rate controller, is modeled, simulated, and experimentally verified.