Research On The Electrical Energy-saving Method Of Waterworks

Waterworks is one of the important infrastructure of city, guaranteeing watersupply for civil, industrial and agricultural use. The rapid development of socialeconomy requires modern waterworks to be large-scale, efficient, environmental,reliable, etc. However, at present, most of the urban waterworks still adopt thetraditional way to supply water, that is, with the constant speed pump or water towerwhich has many disadvantages. Because the output pressure is controlled by human,the control accuracy is low, which cannot satisfy the user’s requirement of reliabilityto water supply system. Moreover, that the pump motor has been in a high-speedoperation causes great waste of electricity. Since the21st century, people graduallyrealize the importance of resources， especially the power resources. The powerresources shortage is particularly serious, which requires the big power userswaterworks to keep up with the trend of the times and to make a big change in termsof energy saving. This paper mainly studies the variable frequency and constantpressure water supplying system from two aspects—high-power inverter harmoniccontrol and control mode.As for the high-power inverter harmonic control, the thesis mainly analyzesseveral typical inverters’ topology structures, working ways and characteristics, andbuilds the simulation model with MATLAB. Through the contrastive analysis of theoutputwaveform and input and output harmonic content of various structures as wellas the comparison with the IEEE-519standard, this thesis, aiming at ruling out theunqualified structure, designs reasonable filter to filter higherharmonic and theparameters for a second-order low-pass filter, and at last, verifies the filtering effectthrough MATLAB simulation.Considering the characteristics of time lag and nonlinearity of water supplysystem, the control mode mainly uses the fuzzy neural network PID control whichintegrates the PID control, fuzzy control, neural network control so as to realize highprecision control to water supply system. The new control puts the fuzzy control andneural network control beside each other. The output of the fuzzy control is utilized asthe input of neural network control, and the PID neuron is regarded as a basicprocessing unit of neural network. The PID neural network avoids the disadvantagethat the standard neural network randomly selects the initial threshold and initialconnection weights, which greatly saves the study time. This thesis constructs the simulation mode of fuzzy neural network PID controller through MATLAB andstimulates the characteristic of step response. After the contrastive analysis betweenthe traditional PID control and fuzzy PID control, this thesis verifies the effectivenessof the new-built control system.