FIELD: measuring.
SUBSTANCE: invention relates to instrumentation and can be used to control pressure of water and other fluids. Instantaneous values of currents and voltages of the asynchronous motor stator are measured, three-phase values of currents and voltages are converted into two-phase components of currents and voltages. Estimates of stator current components are determined at each time interval, and estimates of rotor flux linkage components are calculated. Residual function and its increment are determined from the estimated values of the stator current and the rotor flux linkage. Based on the values of the residual function and its increment, the residual function and the increment of the residual function are determined to be five linguistic variables using a fuzzy logic apparatus. Using the Mamdani fuzzy implication technique, logical variables are interpreted according to a set of rules. At the defuzzification stage, amplification factors of the proportional, integral and differential components are determined by the centre of gravity method. Using the obtained coefficients, the residual function and the increment of the residual function, the angular rotation speed of the rotor of the asynchronous motor is determined. Obtained value of the angular velocity is used to determine the estimates of the stator current, the rotor flux linkage and the residual function at the next step. Instantaneous hydraulic power developed by the centrifugal pump is determined from the values of the electromagnetic moment and the angular speed of rotation of the rotor. Instantaneous volumetric flow rate of the centrifugal pump is determined using values of instantaneous hydraulic power and angular speed of rotation of the rotor of the asynchronous motor. Values of actual flow rate of the pump unit and pressure on the supply pipeline are used to determine the pressure developed by the pump unit.
EFFECT: improving accuracy of determining instantaneous pressure of a centrifugal pump with an asynchronous electric drive in conditions of input signals noise.
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