I. Overview

　　This system can be widely used in wire drawing in metallurgy, petroleum, chemical, textile, electric power, building materials, coal, medicine, food, paper, plastics, printing and dyeing, lifting, cable, washing, water supply, heating, ventilation, sewage treatment and other industries Machines, mixers, extruders, winding machinery, compressors, fan pumps, grinders, conveyor belts, elevators, centrifuges and other equipment.

　　Second, the advantage analysis of brushless doubly-fed motor variable frequency speed regulation system

　　1. Low system cost: The brushless doubly-fed motor variable frequency speed regulation system uses low-power variable frequency control devices to control high-power motors, and low-voltage variable frequency control devices to control high-voltage motors. Therefore, compared with traditional variable frequency speed regulation, the variable frequency control device can be greatly reduced. the cost of. It can reduce equipment investment by 50%.

　　2. High efficiency: The power frequency windings of the brushless doubly-fed motor are directly connected to the grid, and only part of the power is passed through the frequency conversion control device. Therefore, its efficiency is 3.8% higher than that of the traditional asynchronous motor high-voltage frequency conversion speed control system.

　　3. High reliability: (1) Brushless doubly-fed motors eliminate brushes and slip rings, increasing reliability; (2) The reliability of high-voltage inverters is far lower than that of low-voltage inverters, while brushless doubly-fed motors The frequency conversion speed regulation system can control the high voltage motor through the low voltage frequency converter, and the reliability is greatly improved; (3) Ordinary frequency conversion speed regulation system, once the frequency converter fails, the motor will stop running, while the brushless double-fed frequency conversion speed regulation system , When the frequency conversion speed control device fails, it can still automatically switch to the natural synchronous speed operation, which ensures the operation needs to a certain extent and greatly improves the reliability.

　　4. Small footprint: The volume of the equipment is only one-fifth of the volume of the traditional equipment, which can save the investment in the installation site.

　　5. Convenient maintenance: The frequency conversion controller is a low-voltage device, which does not require professional high-voltage operation and maintenance personnel, which can reduce use and maintenance costs.

　　3. Simple estimation of energy saving

　　1. Power consumption of industrial frequency operation:

　　I—Actual operating current; —Estimate according to actual operating conditions

　　2、Power consumption of variable frequency operation:

　　(1)Fan frequency conversion operation：power(KW)=Flow( m³/s)X pressure( )

　　(2)Frequency conversion operation of water pump:

　　 power(KW)=Flow(m³/s ) Head(m) Density( ) Gravitational acceleration(9.8N/kg)/efficiency

　　3、Power saving：

　　4、Power saving rate：

　　5、Save electricity bills annually：

　　H—Number of operating days per year; A—Electricity fee RMB/kwh　

　　Principles of estimation:

　　(1) It can be read but not counted. For most of the power frequency operating conditions, there are power meters or active watt-hour meters for measurement, and the measurement data should be used as the calculation basis

　　(2) It can be measured but not estimated. It is best not to estimate the pressure of the working condition + the resistance pressure of the pipe if there is a measuring hole for the pressure behind the valve.