Research On Variable Frequency Control Method Based On SVPWM And Its Application In Constant Pressure Water Supply System

Variable frequency control has been widely used in constant pressure water supply systems.Conventional variable frequency control methods cannot be fully adapted to the time lag,non-linearity,variability and energy saving characteristics of water supply systems,and have limited capacity to reduce consumption.To address the problems in conventional frequency-controlled constant pressure water supply systems,this paper investigates an SVPWM-based frequency control method to achieve precise speed regulation and energy saving and consumption reduction.The paper analyses the performance characteristics of the asynchronous motor and the variable frequency speed control method,establishes a simulation model of the asynchronous motor with varying input power frequency for the mechanical characteristics of the asynchronous motor at two different variable frequency supply methods above and below the fundamental frequency,and carries out simulation verification to analyse the variable frequency speed control strategy of the asynchronous motor.Based on the mathematical model of the AC asynchronous motor and vector control theory,the principle and implementation rules of the SVPWM variable frequency speed regulation method in the motor are analysed.An SVPWM simulation model is established to verify the variation pattern of its sectors and prove that the utilisation of DC voltage can be improved.Finally,a vector-controlled variable frequency speed control system is built based on SVPWM technology and the vector control mathematical model.Two simulation experiments are designed for the characteristics of the constant voltage water supply system,and the simulation experimental results are analysed,and the results show that the speed regulation performance of the vector control system is very good,whether at constant load or at constant speed,and has the characteristics of small overshoot and fast response speed.Based on the vector control variable frequency speed control system,a variable frequency constant pressure water supply system is designed,containing parts such as the main circuit of the system and the control circuit.And the selection and parameter configuration of the main hardware in it are carried out,and the software of the system is analysed.The upper computer monitoring system was built based on the Win CC configuration platform.The system was run on a trial basis in the water plant.The operation results show that the output power of a single pump motor with frequency regulation decreases with the frequency.The stability of the water supply pressure and the energy saving of the water supply system were compared and analysed.The results show that the water supply system with the frequency conversion control method has a more stable water output pressure,the standard variance of its pressure value is 0.0046 lower than before,and the electricity consumption of water supply per 10,000 tonnes of water is reduced by 5.02%.The frequency conversion control method studied in this paper and its application in the constant pressure water supply system is in line with the current development direction of energy saving and automation of water supply system,and has certain theoretical significance and engineering application value.Figure [61] Table [14] Reference [85]...