In this paper, methods for sizing of PV pumping systems and the simulation of (DTC) Direct Torque Control of induction motor that is used for piloting a water pump supplied by a photovoltaic generator are presented. The sizing of the PV pumping system is based on the calculation of the water needs, the required hydraulic energy and the estimation of available solar power.
The best sizing of the PV pumping system may further help in reducing its cost and optimize its efficiency. The proposed system includes a solar panel, a DC/DC converter with MPPT control, a voltage inverter with pulse width modulation (PWM). The Pump is driven by a Three Phase Induction Motor. In order to control the water flow in the pump, Direct torque control of induction machine is used. The simulations are carried out in Matlab/Simulink.
- PV pumping
- Three phase induction motor
- Induction machine (IM)
- Voltage inverter
- Pulse width modulation (PWM)
Fig. 1. System block diagram
EXPECTED SIMULATION RESULTS:
Fig. 2. Band hysteresis of flux
Fig. 3. Statoric Flux evolution
Fig. 4. Electromagnetic Torque
Fig. 5. Stator current dq Axis
Fig. 6. The motor speed
In this paper, a case study of stand-alone PV pumping system designed for irrigation needs in a remote site in Tunisia. The sizing method for the structure was presented. MPPT technique was used to optimize the power delivered by the photovoltaic module. Direct torque control technique served to control the induction machine speed and therefore the flow of the centrifugal pump. The paper presented the system block diagram, the MPPT control algorithm, the DTC block diagram and design.
The main objective of this work is to maximize savings in energy consumption by ensuring that pipelines and networks are sized and designed accurately. The use of DTC technique ensures better efficiency of the motor. The experimental results are satisfactory and suggest that the proposed solution can be a reliable option to overcome the lack of electricity at remote locations and rural areas. More reliability test and studies needs to be performed to guarantee its robustness, efficiency and cost effectiveness.
 “Solar resource maps for Tunisia”, Solargis S.R.O Slovakia, Maps.
 Chaabane. M, Ben Djemaa. A. and Kossentini, “A daily and hourly global irradiations in Tunisia extracted from Meteosat Wedax images”, Solar Energy, vol. 57, issue 6, pp. 449-457.
 Information obtained from the direction of the bureau of organic farming, CRDA Tozeur.
 T. Augustyn. “Energy efficiency and savings in pumping systems, The holistic approach”, Energy Efficiency Convention (SAEEC), 2012 Southern African.
 Jim McGovern, “Technical Note: Friction Factor Diagrams for Pipe Flow”, Dublin Institute of Technology, 2011.