Optimal Study Of Variable Frequency Water Supply

With the rapid development of frequency control technology, the water supply technology of variable frequency speed regulation has been widely used. Compared with the constant speed water supply system, the frequency conversion speed regulation water supply has the advantages of high energy saving efficiency, automatic control and so on. But the current frequency conversion water supply technology in the operation process there are some technical difficulties, can not show the frequency of water supply equipment or reach the perfect energy saving effect.In this paper, according to the current situation and the existing problems in the real life, it is pointed out that the variable frequency speed regulation range is not adjustable. If the pump speed is too low, there will be a sharp decline in the efficiency of the pump unit, result to non energy conservation. Besides, There will be flow congestion, flow oscillation and other unstable operating conditions.In variable frequency speed regulation technology, the performance of the pump is directly related to the energy saving effect of the speed regulation system.This article through to the pump Q-H characteristic curve shape and different specific speed analysis of the pump performance, and points out that ns=100~350 pump is suitable for the pump speed control.Based on control point in export pump constant pressure control and unconstant pressure control, and control points located at the most unfavorable point control mode are analyzed. It is pointed out that the current variable frequency speed control technology in variable frequency and constant pressure control is one of the most widely used.In the traditional single frequency control technology in the system when the water flow rate is reduced to a certain value of shutting down the variable frequency variable speed large pump, start the pump work, at this time by the small pump and pressure tank joint water supply. In engineering practice, usually small pump flow rate of 1/3~1/2, which is not rigorous. In this paper, the concept of threshold frequency is put forward in view of the condition that the large pump is switched to a small pump in variable frequency speed regulation. In conventional single frequency conversion technology when variable frequency pump start and frequency conversion pump by frequency switching power state when there is a problem of impact current, aiming at this problem and proposes a principle of soft start, soft handover, so as to avoid the huge current impact.Currently in domestic is the most widely used in variable frequency speed control technology is single variable frequency speed control technology. In this paper, the analysis of single frequency conversion water supply technology, points out the existing imbalances area, can not guarantee the frequency control water supply operation efficiently. And then propose two solutions to solve this flow imbalance area. A scheme is the same type of dual frequency conversion timing water supply technology, this scheme can let the pump group in range and efficient operation in addition to the small flow range, good solve the single frequency conversion speed regulation technology in the presence of traffic imbalance problems. In this paper also pointed out that in applying this scheme need to pay attention to is the pump performance to meet the conditions: through the Q-H characteristic curve of pump, a left end point of similar condition of parabola coefficient KA and through, the right endpoint of similar condition of parabola coefficient KB ratio KA/KB≥4; another scheme for different types of pumps in parallel, which pump variable speed pump, small pump for constant speed pump.In this paper, the same model of dual frequency control water supply technology extended digital integrated full frequency constant pressure water supply technology, this technology is based on the theory of dual frequency variable speed water supply technology. Through the analysis of the characteristics, control mode and energy saving of the full frequency constant pressure water supply, the high efficiency and the advantage of the whole frequency conversion constant pressure water supply technology were expounded.