A Single-Stage Sensorless Control of a PV-Based Bore-Well Submersible BLDC Motor

Permanent magnet (PM) brushless dc (BLDC) motor-based photovoltaic water pumps are becoming popular in rural areas due to their higher efficiency and reliability compared to induction motor-based pumps. The water table level in these rural areas is typically more than 15 m. Hence, deep bore-well submersible motors are used for extracting potable water from the water table. The motor and controller are submerged in the water table, and have more temperature rise due to the poor ambience. Thus, control of a PM BLDC motor with hall-effect-based position sensors is unreliable in these environments due to the temperature sensitivity of the hall-effect sensors. In this paper, a single-stage sensorless control of a deep borewell submersible ferrite PM BLDC motor drive is presented. A position sensorless control scheme is implemented to eliminate the use of hall sensors, thus improving reliability of the overall system. Furthermore, the challenges involved in the control of a deep bore-well submersible ferrite PM BLDC motor are elaborated. The prototype of a 1.5-kW submersible BLDC motor drive is fabricated and the experimental results are presented.