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

 ABSTRACT:

 Permanent magnet (PM) brushless dc (BLDC) motor based photovoltaic (PV) water pumps are becoming popular in rural areas due to their higher efficiency, reliability, etc compared to induction motor based pumps. The water table level in these rural areas is typically more than 15 m. Hence, deep borewell 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 halleffect based position sensor 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. Further, 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.

KEYWORDS:

1.      Permanent magnet motors

2.      Brushless dc machines

3.      Sensorless control

4.      Photo-voltaic and bore-well

 SOFTWARE: MATLAB/SIMULINK

 CONCLUSION:

A single-stage sensorless control of a deep bore-well PV based submersible ferrite PM BLDC motor is presented. Borewell pumps have poor ambience and thus hall-effect sensor based control is not reliable in these environments. Further, the PV based water pumps are usually installed in remote rural areas where reliability is a critical factor. Hence, a position sensorless control scheme is implemented to eliminate the use of hall-sensors, thus improving reliability of the overall system. Further, unlike in the existing literature a single stage three phase dc-ac converter is used for achieving both MPP operation and motor commutation. The challenges involved in the fabrication of a deep bore-well submersible ferrite PM BLDC motor are elaborated. The prototype of a 1.5 kW submersible BLDC motor sensorless drive is fabricated and the experimental results are presented. The measured efficiencies of the ferrite BLDC motor and the dc-ac inverter at rated power are 87% and 92%, respectively.

REFERENCES:

[1] M. Mahmoud, “Experience results and techno-economic feasibility of using photovoltaic generators instead of diesel motors for water pumping from rural desert wells in Jordan,” IEE Proceedings C - Generation, Transmission and Distribution, vol. 137, no. 6, pp. 391–394, Nov 1990.

[2] J. L. Davies and M. Malengret, “Application of induction motor for solar water pumping,” in Proc. 3rd AFRICON ’92 Conf., Ezulwini Valley, Sep 1992, pp. 209–212.

[3] E. Muljadi, “PV water pumping with a peak-power tracker using a simple six-step square-wave inverter,” IEEE Trans. Ind. Appl., vol. 33, no. 3, pp. 714–721, May 1997.

[4] J. V. M. Caracas, G. d. C. Farias, L. F. M. Teixeira, and L. A. d. S. Ribeiro, “Implementation of a high-efficiency, high-lifetime, and low-cost converter for an autonomous photovoltaic water pumping system,” IEEE Trans. Ind. Appl., vol. 50, no. 1, pp. 631–641, Jan 2014.

[5] T. R. Brinner, R. H. McCoy, and T. Kopecky, “Induction versus permanent-magnet motors for electric submersible pump field and laboratory comparisons,” IEEE Trans. Ind. Appl., vol. 50, no. 1, pp. 174–181, Jan 2014.