System Introduction Motor cluster control AC/ECFFU
Currently on the market FFU electric power can be divided into AC motor and DC motor. AC motor and single-phase and three-phase branch, power supply voltage of 110V, 220V, 380V are three. AC motor and DC motor phase comparison, has the advantages of simple structure, small volume, convenient manufacture, reliable operation, low price, long service life and a series of advantages, disadvantages is the speed performance is not good. The control mode is divided into control switch, voltage control, frequency control. DC motor has a complex structure, manufacture and maintenance cost is relatively high, it is easy to control, EC motor and low operating cost, good performance of speed adjustment. And compare the following to do a simple analysis of some ordinary control methods.
A, software control; what is software controlled, popular talk is computer control mode usually adopts DC motor, compared with the previous two methods, computer control mode has the advanced function:
Remote control mode 1 can use optional monitor and control.
2 control system for the communication interface, and can communicate with the host computer or network, so as to realize remote communication and management functions.
3 using distributed control, centralized monitoring and control to achieve FFU very convenient.
4 of the FFU motor single, multiple and zoning control convenient.
5 intelligent control system with the energy saving function
Advantages: easy to control DC motor control, wide range of speed control. But this control method also has shortcomings: high cost of the whole system, and the maintenance cost is high.
Two, FFU motor cluster control
Control system of ACFFU motor with PLC system architecture to realize the group control, can realize remote control fan start and stop and to monitor the running status of each group. The general was in grade one thousand, class ten thousand and class one hundred thousand clean room can often see such system.
1 variable frequency control method is to adjust the motor by changing the frequency of speed, at the same time, adjust the input voltage of the motor according to a certain proportion. Frequency conversion control mode has excellent performance, wide range of speed regulation, high speed smooth, high efficiency. Frequency conversion using SPWM control method is advanced, and the SPWM wave is generated by single chip microcomputer. SPWM frequency conversion with other frequency mode has the following characteristics: simple structure, convenient control; high input power factor; fast system dynamic response; little harmonic output. In the present circumstances, compared with voltage mode, frequency conversion mode also has some disadvantages, which is mainly reflected in the following two aspects: frequency conversion control system cost is high; the service life long as regulating mode.
2 pressure control mode, is to adjust the motor by changing the size of the speed of motor stator voltage. Voltage regulation mode of drawback is speed: efficiency is low, high energy consumption, low speed, serious motor heating, such as the narrow speed range. However, pressure regulating method for FFU fan load, its defect is not obvious, and in the current situation has some advantages: speed control scheme of mature, steady speed control system; control system operation is simple, low cost; because the FFU fan load is light, at low speed, the heating of the motor is not very serious pressure regulating speed control mode, and are divided into three kinds of control mode: switch control, variable voltage speed control method and variable frequency speed control mode.
The 3 switch control is by changing the motor stator coils adjust the motor speed. Controller is composed of a control switch and a power switch. The control element is a FFU fan comes, each position distribution in the clean room ceiling, staff must pass through the shifting switch to regulate the FFU motor speed control in the field, very inconvenient, and wind speed FFU motor adjustable range is limited, only a few files. The switch control method has the advantages of simple control, low cost, but there are many defects such as: high energy consumption, not smooth speed etc..