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Title: Pump controller testing on wind turbines used in water pumping

Abstract

Pump controllers for wind-electric water pumping systems were tested on several different size wind turbines at the USDA - Agricultural Research Service, Bushland, Texas. All the wind turbines tested used permanent magnet alternators which generated 3-phase, AC electricity. The wind turbines tested varied in rated power from 1 kW to 10 kW at a wind speed of about 12 m/s. The 3-phase submersible motors tested were all rated at 230 V and the rated power varied from 0.38 kW to 5.6 kW. The pump controllers tested ranged from simple (on/off at certain frequency) to moderately sophisticated (low/high cut-in/cut-out frequency selection with thermal protection for submersible motors). No inverters were used on any of the pumping systems in order to reduce the cost and increase the efficiency of the pumping systems. An inverter isn`t necessary for off-the-shelf AC motors and pumps if the voltage to frequency ratio is maintained between 3 and 4. A voltage to frequency ratio of 3 to 4 was obtained on all the pump controllers tested from the cut-in wind speed to a 13 m/s wind speed by adding the proper capacitance on all three phases. Capacitance was varied on all of the pump controllers tested andmore » it was discovered that optimal capacitance for maximum water pumping performance varied with windspeed. Problems which occurred during the testing which could have been prevented with a modification of the controller were: no water pumping when sufficient winds were available, inability to stop the wind turbine in high winds, blade failures, burned up motors.« less

Authors:
;  [1]
  1. USDA-Agricultural Research Service, Bushland, TX (United States)
Publication Date:
Research Org.:
American Wind Energy Association, Washington, DC (United States)
OSTI Identifier:
269386
Report Number(s):
CONF-950309-
ON: DE96011159; TRN: 96:003988-0051
Resource Type:
Conference
Resource Relation:
Conference: 25. annual conference and exhibition on wind power, Washington, DC (United States), 26-30 Mar 1995; Other Information: PBD: 1995; Related Information: Is Part Of Windpower `95 - Proceedings of the American Wind Energy Association; PB: 624 p.
Country of Publication:
United States
Language:
English
Subject:
17 WIND ENERGY; WATER PUMPS; PERFORMANCE TESTING; WIND TURBINES; CAPACITANCE; ALTERNATORS; COST; EFFICIENCY; FAILURES; FLOW RATE

Citation Formats

Vick, B.D., and Clark, R.N. Pump controller testing on wind turbines used in water pumping. United States: N. p., 1995. Web.
Vick, B.D., & Clark, R.N. Pump controller testing on wind turbines used in water pumping. United States.
Vick, B.D., and Clark, R.N. 1995. "Pump controller testing on wind turbines used in water pumping". United States. doi:.
@article{osti_269386,
title = {Pump controller testing on wind turbines used in water pumping},
author = {Vick, B.D. and Clark, R.N.},
abstractNote = {Pump controllers for wind-electric water pumping systems were tested on several different size wind turbines at the USDA - Agricultural Research Service, Bushland, Texas. All the wind turbines tested used permanent magnet alternators which generated 3-phase, AC electricity. The wind turbines tested varied in rated power from 1 kW to 10 kW at a wind speed of about 12 m/s. The 3-phase submersible motors tested were all rated at 230 V and the rated power varied from 0.38 kW to 5.6 kW. The pump controllers tested ranged from simple (on/off at certain frequency) to moderately sophisticated (low/high cut-in/cut-out frequency selection with thermal protection for submersible motors). No inverters were used on any of the pumping systems in order to reduce the cost and increase the efficiency of the pumping systems. An inverter isn`t necessary for off-the-shelf AC motors and pumps if the voltage to frequency ratio is maintained between 3 and 4. A voltage to frequency ratio of 3 to 4 was obtained on all the pump controllers tested from the cut-in wind speed to a 13 m/s wind speed by adding the proper capacitance on all three phases. Capacitance was varied on all of the pump controllers tested and it was discovered that optimal capacitance for maximum water pumping performance varied with windspeed. Problems which occurred during the testing which could have been prevented with a modification of the controller were: no water pumping when sufficient winds were available, inability to stop the wind turbine in high winds, blade failures, burned up motors.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1995,
month =
}

Conference:
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  • Two different size wind turbines were tested for pumping water at the USDA-Agricultural Research Service, Bushland, Texas. One was a three-bladed 7.0-m diameter wind turbine which was rated at 10 kW at a 12.1 m/s wind speed. The other was a two-bladed 2.75-m diameter wind turbine which was rated at one kW at a 11.0 m/s wind speed. Both wind turbines used a permanent magnet alternator to provide electrical power to a motor which powered a submersible pump. The one kW wind turbine can be used for watering livestock or providing water for a family of four. The 10-kW windmore » turbine can be used for small scale irrigation or providing water for a small village. During the testing of both wind turbine/motor/pump systems, two different motors were tested. The 5.6 kW motor had a 10 percent advantage in system efficiency over the 3.8 kW motor for the 10-kW wind turbine. For the one kw wind turbine the maximum system efficiency was the same for both the 0.38 kW and 0.56 kW motors, but occurred at different wind speeds.« less
  • More and more wind electric water pumping systems are replacing the mechanical windmill for irrigation of crops and watering livestock because the electric systems are more efficient, offer the flexibility to site the turbine some distance from the pump, and require little routine maintenance. The motors and pumps used in most pumping systems were designed to operate at a constant rotational speed. However, the wind electric system operates at variable speed because the electricity generated by the wind turbine is variable frequency. Since the wind turbine operates over a wide range of wind speeds, a controller is needed to maintainmore » stable conditions and improve the system efficiency. Experience of the past ten years with water pumping systems at USDA-Agricultural Research Service (ARS), Bushland, TX, has shown that the wind pumping system operates best when the nameplate voltage to frequency ratio (V/f) is maintained. Using this principle, a smart controller has been designed, built and tested by USDA-ARS and the Alternative Energy Institute, West Texas A and M University for wind electrical pumping systems. Earlier controllers used only the frequency or the voltage to determine the cut-in and cut-out points when electricity from the turbine was connected to the load. This new controller also samples the voltage and calculates the ratio of voltage to frequency. Any abnormal conditions, such as current overload, overheating of generator and loss of one or more phase will drive the V/f ratio below a programmed set point and the controller will disconnect the load and protect the generator and motor from being damaged. This inexpensive controller can allow the pumping system to operate in high wind speed conditions with little risk of damaging the pump motor or wind turbine generator.« less
  • Results are presented of the specific performances of eight, different, water-pumping wind-turbines subjected to impartial tests at the Alberta Renewable Energy Test Site (ARETS), Alberta, Canada. The results presented which were derived from the test data, obtained independently of the equipment manufacturers, are expressed per unit of rotor projected area to eliminate the influence of machine size. Hub-height wind speeds and water flow rates for a common lift of 5.5 m (18 ft) constitute the essential test data. A general finding was that, to a first approximation, there were no major differences in specific performance between four units equipped withmore » conventional reciprocating pumps two of which employed reduction gearing and two of which did not. It was found that a unit equipped with a Moyno pump performed well but three air-lift machines had, as was expected, poorer specific performances than the more conventional equipment. 10 refs., 9 figs.« less
  • Variable-speed, horizontal axis wind turbines use blade-pitch control to meet specified objectives for three regions of operation. This paper focuses on controller design for the constant power production regime. A simple, rigid, non-linear turbine model was used to systematically perform trade-off studies between two performance metrics. Minimization of both the deviation of the rotor speed from the desired speed and the motion of the actuator is obtained through systematic selection of proportional-integral-derivative controller gain values. The gain design is performed using a non-linear turbine model and two linear models. The linear models differ only in selection of linearization point. Themore » gain combinations resulting from design based upon each of the three models are similar. Performance under each of the three gain combinations is acceptable according to the metrics selected. The importance of operating point selection for linear models is illustrated. Because the simulation runs efficiently, the non-linear model provides the best gain design, but careful selection of the linearization point can produce acceptable gain designs from linear models.« less
  • Variable-speed, horizontal axis wind turbines use blade-pitch control to meet specified objectives for three regions of operation. This paper focuses on controller design for the constant power production regime. A simple, rigid, non-linear turbine model was used to systematically perform trade-off studies between two performance metrics. Minimization of both the deviation of the rotor speed from the desired speed and the motion of the actuator is desired. The robust nature of the proportional-integral-derivative (PID) controller is illustrated, and optimal operating conditions are determined. Because numerous simulation runs may be completed in a short time, the relationship of the two opposingmore » metrics is easily visualized. 2 refs., 9 figs.« less