A flow equalizing circuit for water supply system based on pwm filter

Abstract

The invention provides a water supply system flow equalization circuit based on PWM filtering, including: a variable frequency constant pressure equal flow control unit, and a PWM max On-time differential circuit, the circuit is simple in structure, stable and reliable, and low in cost; the parallel variable frequency water supply control system provided has the characteristics of simple structure, low cost, high reliability, and strong practicability, and provides a parallel variable frequency control system for water pumps A new scheme.

Description

technical field [0001] The invention relates to a flow equalization circuit of a water supply system based on PWM filtering, which is especially suitable for water supply occasions in a parallel frequency conversion water supply system that requires high balance of water supply flow of each water pump. Background technique [0002] At present, frequency conversion constant pressure water supply systems in waterworks and secondary pressurized water supply in residential areas usually use multiple frequency conversion pumps in parallel to increase their water supply capacity. The commonly used parallel frequency conversion constant pressure water supply system mainly realizes constant pressure water supply to ensure that the water supply pressure meets the requirements. Since there are certain differences between each water pump and the frequency conversion controller, if the uniform output flow control of each water pump in the water supply system is not carried out, it will ...

AI Technical Summary

Problems solved by technology

[0004] However, such a parallel frequency conversion constant pressure water supply system will have a very common problem - that is, the output flow of the pump is unbalanced.

[0005] Due to the inconsistency of water pumps, frequency converters, water inlet and outlet pipes, etc., only the water supply pressure is controlled, and the output flow of each water pump cannot be balanced.

Parallel water supply mode is adopted, because of the same water outlet head, the flow rate of the water pump with small equivalent pipe resistance is relatively large, resulting in a relatively large output power load

At the same time, the flow rate of the pump with large equivalent pipe resistance is relatively small, resulting in a relatively small output power load

In severe cases, the pumps and frequency converters with large output flow are overloaded, which increases the probability of mechanical and electrical failures and shortens their lifespan; the operating frequency of water pumps and frequency converters with small output flow is too low, which causes serious low-frequency heating of the pumps and lowers the efficiency. Low, which also leads to an increase in the probability of electrical failure of the equipment and a shortened life span

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