CN204961364U - Air suspension centrifugal fan control system - Google Patents

Abstract

The utility model discloses an air suspension centrifugal fan control system, which comprises a temperature control unit, a pressure control unit, a PLC host, a frequency converter and a man-machine interface display unit; the output ends of the temperature control unit and the pressure control unit are respectively connected to the into the corresponding input terminal of the PLC host, the man-machine interface display unit is bidirectionally connected to the PLC host, the output terminal of the PLC host is connected to the input terminal of the frequency converter, and the output terminal of the frequency converter is connected to the controlled The input end of the air suspension centrifugal fan; the temperature control unit includes a number of temperature sensors and temperature modules; a number of the temperature sensors are distributed on the motor of the controlled air suspension centrifugal fan, the air inlet, the air outlet and the circulation In the cooling liquid; the pressure control unit includes a first differential pressure transmitter, a second differential pressure transmitter and an analog quantity acquisition module. The utility model has the advantages of safety, energy saving, simplicity and high efficiency, and can realize no-load start-stop and control.

Description

An air suspension centrifugal fan control system

technical field

The utility model belongs to the field of fan control systems, in particular to an air suspension centrifugal fan control system.

Background technique

In recent years, PLC has been widely used with its many excellent features, and has become the standard equipment of industrial control in industrially advanced countries. It is specially designed for industrial control, integrating electrical, instrumentation and control, and is an ideal control device for realizing mechatronics.

Conventional centrifugal blowers, referred to as centrifugal fans, mostly use traditional relay control circuits in their control systems, and a large number of intermediate relays and time relays are used in traditional blower relay control circuits. Failure and accidents are prone to occur due to poor contacts.

Due to the extensive use of traditional relays, the control system is bloated and compact, and the wiring is cumbersome. Control lines and power lines are mixed alternately. It is easy to cause electrical fire due to poor heat dissipation.

Traditional control systems require many different types of sensors, and one of the biggest killers of sensors is electromagnetic interference. Due to the extensive use of traditional relays, sensor malfunctions due to electromagnetic interference are most likely to occur during the relay action process. When malfunctions occur, equipment damage can range from equipment damage to personal accidents.

The traditional star-delta step-down start-up and auto-coupling step-down start-up are often used in the speed regulation of the traditional blower system, which cannot effectively adjust the speed of the blower in a timely manner, and its own energy consumption is high. Moreover, the volume of the control system itself increases with the increase in the power of the blower. become larger. In a relatively harsh and dangerous gas environment, the safety factor is low. It may cause sudden accidents due to ignition of traditional contactor contacts during operation.

Utility model content

The technical problem to be solved by the utility model is to provide an air suspension centrifugal fan control system that is safe, energy-saving, simple and efficient, and can realize no-load start-stop and control.

The technical scheme adopted in the utility model is as follows:

An air suspension centrifugal fan control system, which includes a temperature control unit, a pressure control unit, a PLC host, a frequency converter, and a man-machine interface display unit; the output terminals of the temperature control unit and the pressure control unit are respectively connected to the corresponding The input end, the man-machine interface display unit is bidirectionally connected to the PLC host, the output end of the PLC host is connected to the input end of the frequency converter, and the output end of the frequency converter is connected to the controlled air suspension centrifugal fan. input.

Further, the temperature control unit includes a number of temperature sensors and a temperature module; a number of the temperature sensors are connected to the input end of the PLC host through the temperature module, and a number of the temperature sensors are distributed in the controlled air suspension centrifugal fan On the motor, at the air inlet, at the air outlet and in the circulating coolant.

Further, the pressure control unit includes a first differential pressure transmitter, a second differential pressure transmitter and an analog quantity acquisition module; the output ends of the first differential pressure transmitter and the second differential pressure transmitter The input end of the PLC host is connected through an analog quantity acquisition module; the high-voltage end of the first differential pressure transmitter is connected to the air outlet of the controlled air suspension centrifugal fan, and the second differential pressure transmitter The low pressure end of the transmitter is connected to the air inlet of the controlled air suspension centrifugal fan, and the high pressure end of the second differential pressure transmitter is connected to the atmospheric pressure inside the fan box. Since the controlled air-suspension centrifugal fan has a box, the air-suspension centrifugal fan operates in the box.

Further, the frequency converter is powered by a three-phase four-wire power supply, and the three-phase four-wire power supply is connected to the frequency converter via a main power circuit breaker and an input reactor in sequence.

The utility model also includes an output reactor, and the frequency converter is connected to the controlled air suspension centrifugal fan through the output reactor.

Further, the man-machine interface display unit includes a touch screen, and the corresponding output terminals of the PLC host are connected to the touch screen.

Further, the model of the temperature sensor is PT100; the first differential pressure transmitter is Celsus A4-0-200KPA and the model of the second differential pressure transmitter is Celsus A4-0- 15KPA; the model of the temperature module is DVP-04PT-S; the model of the analog acquisition module is DVP-06AD-S; the model of the PLC host is DVP-28SV; the model of the inverter is Viken NXP-200KW series.

Further, the PLC host is powered by a three-phase four-wire power supply, and the three-phase four-wire power supply is connected to the PLC host through a main power circuit breaker, an isolation transformer and its electric control part in sequence.

The beneficial effects of the utility model are as follows:

(1) This system organically combines the PLC host with the frequency converter, adopts the feedback value calculated by the temperature sensor, the first differential pressure transmitter and the second differential pressure transmitter as the main control parameter, and adjusts it through PID Effective control of the working process and operating speed of the air-suspension centrifugal blower is realized, so that the air-suspension centrifugal blower is efficient and safe, and an obvious energy-saving effect is achieved.

(2) This system has functional characteristics such as overheat protection, fault alarm, mechanical fault alarm and power failure of the motor driving the fan, and provides a new way for the energy-saving technical transformation of the air suspension centrifugal blower.

(3) Compared with the conventional control system, this system adopts modular design, which greatly saves installation and debugging time; the physical connection lines between modules are few and simple; all function keys of this system are all used in the man-machine The interface display unit is a virtual button made on the touch screen, one-button operation, and the humanized design allows the operator to quickly master the operation, which greatly saves the volume of the control cabinet and the cumbersome wiring of buttons and indicators.

(4) This system adopts PLC host computer to control industrial production automation control, which has the following advantages compared with the traditional relay control system:

4-1． Fast response, low noise, low energy consumption, small size;

4-2. Powerful functions, convenient programming, can modify the program at any time;

4-3. High control precision, capable of complex program control;

4-4. Able to automatically detect the control process;

4-5. The system is stable, safe and reliable.

Description of drawings

Fig. 1 is a structural principle block diagram of the utility model.

Figure 2 is the operating curve of the system in the constant air volume control mode.

Figure 3 is the operating curve of the system in the constant air pressure control mode.

detailed description

Below in conjunction with specific embodiment and accompanying drawing 1-3 of description, the utility model is described in further detail.

As shown in Figures 1 to 3, it includes a temperature control unit, a pressure control unit, a PLC host, a frequency converter, and a man-machine interface display unit; the output terminals of the temperature control unit and the pressure control unit are respectively connected to the corresponding The input end, the man-machine interface display unit is bidirectionally connected to the PLC host, the output end of the PLC host is connected to the input end of the frequency converter, and the output end of the frequency converter is connected to the controlled air suspension centrifugal fan. input.

Further, the temperature control unit includes a number of temperature sensors and a temperature module; a number of the temperature sensors are connected to the input end of the PLC host through the temperature module, and a number of the temperature sensors are distributed in the controlled air suspension centrifugal fan On the motor, at the air inlet, at the air outlet and in the circulating coolant.

Further, the pressure control unit includes a first differential pressure transmitter, a second differential pressure transmitter and an analog quantity acquisition module; the output ends of the first differential pressure transmitter and the second differential pressure transmitter The input end of the PLC host is connected through an analog quantity acquisition module; the high-voltage end of the first differential pressure transmitter is connected to the air outlet of the controlled air suspension centrifugal fan, and the second differential pressure transmitter The low pressure end of the transmitter is connected to the air inlet of the controlled air suspension centrifugal fan, and the high pressure end of the second differential pressure transmitter is connected to the atmospheric pressure inside the fan box.

Further, the frequency converter is powered by a three-phase four-wire power supply, and the three-phase four-wire power supply is connected to the frequency converter via a main power circuit breaker and an input reactor in sequence.

The utility model also includes an output reactor, and the frequency converter is connected to the controlled air suspension centrifugal fan through the output reactor.

Further, the man-machine interface display unit includes a touch screen, and the corresponding output terminals of the PLC host are connected to the touch screen.

Further, the model of the temperature sensor is PT100; the first differential pressure transmitter is Celsus A4-0-200KPA and the model of the second differential pressure transmitter is Celsus A4-0- 15KPA; the model of the temperature module is DVP-04PT-S; the model of the analog acquisition module is DVP-06AD-S; the model of the PLC host is DVP-28SV; the model of the inverter is Viken NXP -200KW series.

Further, the three-phase four-wire power supply is input to the electric control part through the main power circuit breaker and the isolation transformer, and is input to supply power to the PLC mainframe through the electric control part, and then supplies power to the temperature sensor, the first differential pressure transmitter and the first differential pressure transmitter connected to the PLC mainframe. The second differential pressure transmitter is powered.

The working principle of the utility model is as follows:

This system adopts Delta DVP-28SV series PLC as the host computer and adds corresponding expansion modules. DVP04PT-S temperature module and DVP-06AD-S analog acquisition module constitute the core of the control system. This system has the functions of starting, interlocking and overheating protection of the centrifugal fan. It also includes contactors, intermediate relays, thermal relays, circuit breakers and other system protection appliances to achieve effective protection of the motor and PLC host, as well as PID control of the motor. Compared with the fan system implemented by conventional relays, the system composed of PLC hosts has many advantages such as low failure rate, high reliability, simple wiring, and convenient maintenance. The control function composed of PLC hosts greatly improves the automation of the fan system and reduces the The labor intensity of the post personnel. The PLC host and frequency converter are used in conjunction with differential pressure transmitters and temperature sensors, which greatly improves the safety and reliability of system control, and also greatly reduces the failure rate of fan operation, which not only saves electric energy, but also improves equipment reliability. operating rate.

The design requirements of the present utility model are as follows:

(1) The system provides manual/automatic two working modes, and has functions such as status display and fault alarm.

(2) The pressure/flow analog signal is input to the PLC host through PID calculation, and the frequency converter is controlled through the ModBus-485 communication port of the PLC host, and the field signal is converted into a unified standard signal by using a differential pressure transmitter, such as 4~20mA DC current Signals, 0~5V DC voltage signals, etc., are sent to the A/D converter for analog-to-digital conversion, and then sent to the PLC host. The PLC host compares and processes the detected air pressure value with the set air pressure value, and outputs signal control The frequency converter makes the fan work.

(3) In the constant wind pressure control mode, when the pressure on the air outlet side is lower than the lower limit of the set pressure, the signal fed back by the pressure transmitter on the outlet side will perform PID calculation in the PLC host, and control the frequency converter to make the fan run at a high speed Increase to ensure that the pressure on the outlet side operates within the range of the set pressure.

(4) In the constant air volume control mode, when the flow rate is lower than the set lower limit, the signals fed back by the first differential pressure transmitter and the second differential pressure transmitter are calculated in the PLC host, and the inverter is controlled to use The running speed of the fan is increased to ensure that the flow of the fan is within the range of the set flow.

(5) PID control mode

In engineering practice, the most widely used regulator control law is proportional, integral, differential control, referred to as PID control, also known as PID regulation. It has been nearly 70 years since the PID controller came out. It has become one of the main technologies of industrial control because of its simple structure, good stability, reliable operation and convenient adjustment. When the structure and parameters of the controlled object cannot be fully grasped, or an accurate mathematical model cannot be obtained, and other techniques of control theory are difficult to adopt, the structure and parameters of the system controller must be determined by experience and on-site debugging. At this time, the application PID control technology is the most convenient. That is, when we do not fully understand a system and the controlled object, or cannot obtain system parameters through effective measurement means, it is most suitable to use PID control technology. PID control, in practice there are also PI and PD control. The PID controller is based on the error of the system, using proportional, integral, and differential to calculate the control amount for control. PID control belongs to closed-loop control. The monitoring signal of the controlled quantity, that is, the actual value detected by the pressure sensor or flow sensor, is fed back to the PLC host or frequency converter, and compared with the target signal of the controlled quantity, it is judged whether the predetermined control purpose is achieved. If it is not achieved, it will be automatically adjusted according to the difference between the two until the predetermined control purpose is achieved.

As shown in Figure 2, the flow control is set to Qset. After the blower is started, it climbs to the No. 1 operating point along the high-efficiency curve, that is, the No. 1 curve, and maintains stable operation after reaching the set air volume value. The air outlet pipeline system will cause the back pressure to fluctuate due to the change of the system resistance. When the back pressure increases, the working point will drift to the No. 2 point, resulting in a decrease in the air volume. Feedback to the PLC system and calculate the air volume at this time. At this time, the blower will automatically detect this change, and automatically compensate the speed, and push the operating point to 2' to continue to maintain the constant air volume of the blower. Conversely, when the back pressure decreases, the operating point will drift to point 3, causing the air volume to increase. The pressure sensor and differential pressure transmitter in the system will feed back to the PLC system and calculate the air volume at this time. At this time, the blower will automatically detect When this change is detected, the speed will be automatically lowered accordingly, and the working point will be pushed to 3', so as to keep the air volume of the blower unchanged, and also achieve the purpose of energy saving.

As shown in Figure 3, the air pressure control is set to △Pset, and the blower climbs to the operating point No. 1 along the high-efficiency curve, that is, curve No. 1 after starting, and maintains stable operation after reaching the set air pressure value. The back pressure of the air outlet will fluctuate due to the change of the air volume demand of the system. When the air volume demand increases, the working point will drift to the No. 2 point, causing the air pressure to drop. At this time, the pressure transmitter will sense the pressure drop, and the blower will automatically This change is detected, and the rotational speed is automatically compensated, and the operating point is pushed to 2', so as to continue to keep the blower air pressure constant. Conversely, when the demand for air volume decreases, the operating point will drift to point 3, resulting in an increase in wind pressure. At this time, the pressure transmitter will sense the increase in pressure. At this time, the blower will automatically detect this change and automatically lower it accordingly. The rotating speed pushes the operating point to the 3' point to keep the air pressure of the blower constant, and also achieves the purpose of energy saving.

(6) The temperature sensor PT100 measures the stator temperature or bearing temperature of the fan unit. When the stator temperature or bearing temperature exceeds the PLC host internal program setting alarm and goes online, it is judged by the PLC host internal program and sent to the man-machine interface display unit, that is The HMI alarm screen sends out instructions and alarm signals; when the stator temperature or bearing temperature exceeds the set normal fan operating temperature boundary, the PLC host will calculate and judge that the temperature has been exceeded based on the collected temperature data, and then cut off the instructions and alarm signals and automatically Cut off the currently running fan unit.

(7) Use the pneumatic solenoid valve and vent valve to control the no-load start and stop of the fan and prevent surge. When the fan is started, the vent valve is open and the fan outlet is connected to the atmosphere to reduce the starting current of the fan and prevent the fan from overloading; when the fan is running, the vent valve is slowly closed to reduce the current impact when entering the working environment; when the fan is stopped, the vent valve Instantaneous opening prevents the air in the pipeline from flowing backwards. Instantly opening the vent valve when surge is about to occur can effectively avoid equipment damage caused by surge.

Instructions for the selection of frequency converters:

Using NXS or NXP series industrial inverters from Finland, VACON NXS is equipped with a fully functional modular application macro software package and PC software tools, which can widely meet the needs of many drive applications. In addition, users can use PC software tools to realize various functions such as engineering design, parameter setting and uploading, and system monitoring. Rich control panel option cards can be selected according to the control requirements. According to the control requirements, we choose the basic I/O card OPT-A2 and the field bus card OPT-C2 two option cards. The control requirements need to alarm when the inverter fails. Select the basic I/O card OPT-A2, which is a two-way relay output card. Through the parameter setting of the inverter, the relay can be turned on when the inverter fails to output signals to the PLC host and output to the alarm unit. . The field bus card OPT-C2 is a RS-485 multi-protocol communication card, used to receive control data online with the PLC host.

Instructions for the selection of temperature sensors:

The model of the temperature sensor shown is PT-100. The PT-100 type is a sensor that converts temperature variables into standardized output signals that can be transmitted. It is mainly used for the measurement and control of industrial process temperature parameters. Pt100 means that the resistance value is 100 ohms at 0 degrees. The PT100 temperature sensor is a resistive temperature sensor made of platinum (Pt), which belongs to positive resistivity. The relationship between its resistance and temperature change is as follows:

R=Ro(1+αT)

The main technical parameters of the Pt100 temperature sensor are as follows:

Measuring range: -200℃～+850℃;

Allowable deviation value △℃: Grade A ±(0.15＋0.002│t│),

Grade B±(0.30＋0.005│t│);

Thermal response time current ≤5mA.

In addition, the Pt100 temperature sensor also has the advantages of anti-vibration, good stability, high accuracy, and high pressure resistance, and has rich interfaces. The shape and length of the probe and the size of the threaded connection can be customized according to customer requirements.

Instructions for the selection of differential pressure transmitters:

Differential pressure transmitter is the most commonly used pressure transmitter in industrial practice. It is widely used in various industrial automatic control environments, involving oil pipelines, water conservancy and hydropower, railway transportation, intelligent buildings, production automatic control, aerospace, military, Petrochemical, oil well, electric power, ship, machine tool, pipeline air supply, boiler negative pressure and many other industries. The working principle of the transmitter is that the pressure of the differential pressure sensor directly acts on the diaphragm of the sensor, causing the diaphragm to produce a micro-displacement proportional to the medium pressure, causing the resistance of the sensor to change, and the electronic circuit is used to detect this change, and The converter outputs a standard signal corresponding to this pressure. Its output signal: 4-20mA, two-wire system.

The purposes and effects of the main devices used in this embodiment:

1. The use and function of the isolation transformer:

Isolation transformer refers to a transformer with electrical isolation between the input winding and the output winding. The isolation transformer is used to avoid accidental contact with the live body at the same time. The isolation of the transformer is to isolate the respective currents of the primary and secondary coils. In the early days, it was used in the electric power industry in European countries, and was widely used in the control power supply of general circuits in the electronics industry or industrial and mining enterprises, machine tools and mechanical equipment, as well as the power supply of safety lighting and indicator lights.

First of all, one line of the AC power supply voltage we usually use is connected to the ground, and there is a potential difference of 220V between the other line and the ground. Human contact will cause electric shock. The secondary of the isolation transformer is not connected to the ground, and there is no potential difference between any two lines of it and the ground. People will not get an electric shock if they touch any line, so it is safer.

Secondly, the output terminal of the isolation transformer is completely "open circuit" isolated from the input terminal, which effectively plays a good role in filtering the input terminal of the transformer, that is, the power supply voltage supplied by the grid. Thereby providing a pure power supply voltage to the electrical equipment. Another use is anti-jamming.

effect:

The main function of the isolation transformer is to completely insulate the primary side from the secondary side and also isolate the circuit. In addition, the high-frequency loss of the iron core is used to suppress high-frequency clutter from entering the control loop. Using an isolation transformer to suspend the secondary to the ground can only be used in occasions where the power supply range is small and the line is short. At this time, the capacitance current of the system to ground is too small to cause personal injury. Another very important role is to protect personal safety! Isolate hazardous voltages.

2. The use and function of the phase sequence protector:

The phase sequence protector is a kind of control relay. It is a protective relay that can automatically distinguish the phase sequence, so as to ensure that some special electromechanical equipment will cause accidents or equipment damage due to reversed power supply phase sequence.

The three-phase power supply is sampled and processed. When the phase sequence of the power supply matches the phase sequence input by the protector terminal, the output relay is connected and the main control circuit of the equipment is connected. There are two types of products: one is: when the phase sequence of the power supply changes, the phase sequence does not match, and the output relay cannot be connected, thereby protecting the equipment and avoiding accidents; the other type uses digital microchip technology products, which can realize automatic Phase sequence recognition and automatic phase sequence conversion to ensure constant phase sequence rotation of the motor.

The three-phase power supply is sequentially connected to the R, S, T or L1, L2, and L3 connection points of the protector. The auxiliary contacts of the phase sequence protector generally have one normally open and one normally closed. Connect to the control circuit, whether to connect to normally open or normally closed according to the control principle or wiring diagram. When the phase sequence is wrong or the phase is missing, the auxiliary contact of the protector moves from normally open to normally closed, and from normally closed to normally open . If it plays a protective role, it should be connected to a normally closed contact.

3. The use and function of the comprehensive motor protector:

The motor comprehensive protector is a comprehensive protection for the motor, mainly for three-phase current detection and monitoring. , When the stator and rotor are eccentric, the alarm or protection device is given.

4. The use and function of the input reactor:

The input reactor is connected between the power supply and the inverter. It can limit the current impact caused by the sudden change of the grid voltage and the operating overvoltage, effectively protect the inverter and improve the power factor of the inverter, and suppress the harmonics of the inverter input grid. Current product features: reduce the noise of the motor and reduce the eddy current loss.

The output reactor, called "OutputReactor" in English, is mainly used in industrial automation system engineering, especially in the occasion of using frequency converter, to extend the effective transmission distance of the frequency converter and effectively suppress the momentary moment when the IGBT module of the frequency converter is switched high pressure.

5. The use and function of differential pressure transmitter:

The differential pressure transmitter is a transmitter that measures the pressure difference between the two ends of the transmitter, and outputs standard signals, such as 4~20mA, 0~5V. Differential pressure transmitters are different from ordinary pressure transmitters in that they all have two pressure ports. Differential pressure transmitters are generally divided into positive pressure ends and negative pressure ends. The pressure at the end should be greater than the pressure at the negative pressure section to be measured.

6. The use and function of switching power supply:

Switching power supply is a kind of power supply that uses modern power electronic technology to control the time ratio of switching on and off to maintain a stable output voltage. Switching power supply is generally composed of pulse width modulation (PWM) control IC and MOSFET. With the development and innovation of power electronics technology, switching power supply technology is constantly innovating. At present, switching power supply is widely used in almost all electronic devices due to its small size, light weight and high efficiency. It is an indispensable power supply method for the rapid development of today's electronic information industry.

Switching power supply products are widely used in industrial automation control, military equipment, scientific research equipment, LED lighting, industrial control equipment, communication equipment, electrical equipment, instrumentation, medical equipment, semiconductor refrigeration and heating, air purifiers, electronic refrigerators, liquid crystal displays, LED Lamps, communication equipment, audio-visual products, security monitoring, LED light bags, computer cases, digital products and instruments and other fields.

There are two types of modern switching power supplies: one is DC switching power supply; the other is AC switching power supply.

7. The use and function of the man-machine interface display unit:

Human Machine Interface, HumanMachineInteraction, HMI for short, also known as user interface or user interface, is a medium and dialogue interface for transmitting and exchanging information between humans and computers, and is an important part of computer systems. It is a medium for interaction and information exchange between the system and users, and it realizes the conversion between the internal form of information and the form acceptable to humans. There is a human-machine interface in any field that participates in the exchange of human-computer information.

This patent mainly reflects the composition of the control system of the high-speed centrifugal blower. The control system is mainly divided into three parts, one is the power supply part of the whole system, the other is the PLC control and HMI display part, and the third is the motor drive part.

The control system combined with PLC and frequency converter is compared with the blower system controlled by traditional relay. The combination of PLC and frequency converter has inherent comprehensive advantages.

The advantages of PLC and inverter are as follows:

1. Strong function, high cost performance;

2. The hardware is complete, the user is easy to use, and the adaptability is strong;

3. High reliability and strong anti-interference ability;

4. The design, installation and commissioning of the system are less work;

5. The programming method is simple;

6. The maintenance workload is less and the maintenance is convenient;

7. Small size and low energy consumption;

8. Keep pace with the times and realize network communication;

9. Improve product technology content and increase product image;

10. It is very convenient for future mechanical upgrades;

11. Speed adjustment is convenient and fast.

The above-mentioned implementations are only preferred embodiments of the present utility model, rather than an exhaustive list of feasible implementations of the present utility model. For those skilled in the art, any obvious changes made without departing from the principle and spirit of the utility model should be considered to be included in the protection scope of the claims of the utility model.

Claims (7)

1. an air suspension centrifugal blower control system, is characterized in that: it comprises temperature control unit, pressure control unit, PLC main frame, frequency variator and man-machine interface display unit; The output terminal of described temperature control unit and pressure control unit accesses the respective input of PLC main frame respectively, described man-machine interface display unit and PLC main frame are bi-directionally connected, the input end of the output terminal access frequency variator of described PLC main frame, the input end of the described controlled air suspension centrifugal blower of output terminal access of described frequency variator.

2. a kind of air suspension centrifugal blower control system according to claim 1, is characterized in that: described temperature control unit comprises some temperature transducers and thermal module; Some described temperature transducers access the input end of described PLC main frame by thermal module, some described temperature transducers are distributed on the motor of described controlled air suspension centrifugal blower, wind inlet place, in exhaust outlet place and circulating cooling liquid.

3., according to the arbitrary described a kind of air suspension centrifugal blower control system of claim 1 or 2, it is characterized in that: described pressure control unit comprises the first differential pressure transmitter, the second differential pressure transmitter and analogue collection module; The output terminal of described first differential pressure transmitter and the second differential pressure transmitter accesses the input end of described PLC main frame by analogue collection module; The high voltage terminal of described first differential pressure transmitter is connected on the exhaust outlet of described controlled air suspension centrifugal blower, the low voltage terminal of described second differential pressure transmitter is connected on the wind inlet of described controlled air suspension centrifugal blower, and the high voltage terminal of described second differential pressure transmitter is connected on barometric pressure place in described fan box.

4. a kind of air suspension centrifugal blower control system according to claim 1, is characterized in that: described frequency variator is powered by three-phase four-wire power, and described three-phase four-wire power is successively through general power circuit breaker, input reactance device access frequency variator.

5. according to the arbitrary described a kind of air suspension centrifugal blower control system of claim 1 or 4, it is characterized in that: it also comprises out put reactor, described frequency variator is through the described controlled air suspension centrifugal blower of described out put reactor access.

6. a kind of air suspension centrifugal blower control system according to claim 2, is characterized in that: the model of described temperature transducer is PT100; Described first differential pressure transmitter is the model of Sai Ersesi A4-0-200KPA and the second differential pressure transmitter is Sai Ersesi A4-0-15KPA; The model of described thermal module is DVP-04PT-S; The model of described analogue collection module is DVP-06AD; The model of described PLC main frame is DVP-28SV; The model of described frequency variator is big willing NXP-200KW series.

7. a kind of air suspension centrifugal blower control system according to claim 1, it is characterized in that: described PLC main frame is powered by three-phase four-wire power, and described three-phase four-wire power is tapped into PLC main frame through general power circuit breaker, isolating transformer and electric control part thereof successively.