【 Weak current college 】 more module inverter technology in clean air conditioning system---Power By 【 China power house network 】

1 multiple module inverter
More module converter is completely uses the flux vector control of inverter technology, is currently the representative frequency converter development direction of the next generation of modular high-performance converter. To meet customer needs for performance, functionality, the conventional transducer General through numerous series products to achieve (and therefore will increase the additional design, manufacturing, inventory, sales, use, maintenance, and other link costs), while many module inverter is in reasonable breakdown on the basis of customer demand, for modular design of the function, and a simple series of different combinations of multiple modules, create one in order to satisfy customer demands as the target volume shendu's platform.
More module converter adopts advanced no velocity vector control strategies, it has a fast dynamic response; also adopts advanced current limiting technology and hardware to optimize the design, so even if the work load frequent fluctuations, ensure the inverter does not trip. More module converter also has the following characteristics:
(1) high starting torque
As a result of the high-performance magnetic flux vector control technology and no velocity vector control strategies in low frequency band provides stability and high output torque, low energy consumption to maintain laboratory in non-work time of positive pressure, and can work within a short time before quickly restored to a working state, and to quickly reach the volume balance.
(2) stability
Compared with the frequency starting way, using multiple module Inverter control can reduce the fan starts and runs of mechanical parts and on the impact of the framework, reducing laboratory Institute of environmental noise, to save costs for operation and maintenance of, and running stable.
(3) reliable running
For on-site installation and commissioning, with perfect reliability design, such as redundant design, design, etc.; Derating with military-grade components; specialized technology platform, thereby ensuring the reliability of the machine running.

2 more module inverter compressor operation control
2.1 air compressor control features
According to the air compression theory, compressor shaft power, displacement and shaft speed is proportional to each other, without changing the cylinder capacity of the compressor, the compressor speed adjustment by can adjust exhaust volume; compressor is constant torque load, compressor shaft power and speed is proportional to the change. Adjust the compressor condition changes, by adjusting the compressor speed regulation for wind pressure, achieve economic operation of the compressor. More module inverter and compressor pole motor, changed pulley ratio, with a speed and speed than with startup fast and stable, non-Polar speed and easy to fulfill automatic control, running stable and reliable, maintenance workload characteristics, especially those with no change in the structure and field equipment installation and commissioning effort smaller features.
More module inverter another big advantage is that the pressure set conveniently, according to the consumption of changes at any time adjust the set value, easy to implement pressure closed loop operation, thus achieving a constant pressure of the compressor.

2.2 more module Inverter control requirements
Air compressor is a constant torque load, use multiple module inverter is the main purpose of the air volume as needed to adjust the supply pressure of a given value, achieve steady voltage energy saving operation. In principle, you can press kit motor rated power use the same capacity of constant torque converter, built-in PID function and current or voltage analog signal interface; field voltage rate of change in the frequency converter allows input voltage range.

2.3 installation debugging and running tests
Air pressure sensor installed inthe total exhaust tube, feedback output pressure signal to the scene of the DDC, BA system from DDC converted to frequency converter can be recognized by the analog voltage signal or current signal (0-5V, 0-10V, 4-20mA) by repeatedly adjust the given values meet the design goals. In the actual construction, according to the design requirements also retains its power standby device, once the inverter fails, you can use the power system, ensure the continuation of the science test.
System installed to use after running smoothly, the working pressure remains constant, the more module inverter compressor run automatically. Since the adoption of more module converter implements the compressor working pressure in closed-loop control, with the original is not using multiple modules of purifying lab inverter technology, significantly reduces the number of starting and stopping the compressor reduces the laboratory personnel maintain strength, saving energy consumption, reduces wear and extends the service life of the compressor, improving economic efficiency and energy saving effect.

3 multiple module inverter on fan filter unit (FFU) air volume balance control
Air flow balance is an important part of the laboratory cleanliness, past the automatic control systems are very difficult to achieve control requirements, its outstanding performance in the first automatic control system instability, adjustable range is too large, it is difficult to truly achieve the purpose of automatic control, and prone to malfunction. Besides the automatic control system relies on the mechanical system to perform an action, the air conditioning system of mechanical parts and seriously affect the automatic control system's normal operation. So many of the air conditioning running management departments, the automatic control system off, do not use automatic instead of manually. Third, the evaluation of air conditioning system is functioning correctly, often rely on prior thermometer, hygrometer, flow meter to measure, increasing administrative workload. Through multiple module inverter for precise control of FFU successfully solved the puzzle.
(1) to meet the design requirements, indoor air flow balance is to guarantee the cleanliness of critical business interactions. Inverter application of to ensure air flow dynamic balance.
(2) due to air flow change control within the set, make sure that the air does not produce turbulent phenomenon, the indoor air distribution according to law and order flow.
(3) as a result of reduced air flow change value, effectively protect the HEPA filter is not affected by the impact and extends the service life of high efficiency filter.
(4) number of the application of the module variable frequency controllers, in the control of indoor air flow, temperature and humidity changes, adjustments to the indoor air parameters, will become very convenient.
(5) and BA system good cohesion
The whole experiment building useUnited States allesz company of WebCTRL system, combined with its on-site DDC controllers, on the new blower group and exhaust fan group switch control, and automatic air conditioning, measurement by DDC appropriate air conditioning unit's operational status and trend analysis and calculation, automatic adjustment of the fan of frequency inverter multi module, allows airflow control in the design of control, achieve the best control effect. Table 1 is the number to the system air flow design 46J-1 and measured data comparison table.
Table 1 point duct size cross wind speed (m/s) air flow (m3/h) notes design determination design determination mmm2 A2000 * 9001.806.737.344364047531 inverter frequency: 40HzB1000 * 4000.404.992.8171904050C1800 * 8001.447.938.174110043481 conclusion: meet the design requirements
(6) in order to prevent outdoor air purifying indoor, adjust the system of ventilation and exhaust volume to ensure clean indoor outdoor with the positive pressure 10Pa. As a result of the multiple module inverter technology, leads to a clean air conditioning controls and air balance control is very accurate and easy to implement, so testing cleanliness, each getting sample 3 times, the final system cleanliness test results superior to the design requirements, of which 100-level district .5μm particle concentration average no more than 10/cubic foot, less than the design requirements of 100/cubic feet, the room temperature 22 ° c in the design of control at ± 2 ℃ error, φ ≤ 40% relative humidity.

4 closing
More module variable frequency control technology still belong to the traditional motion control system application in the framework of a new idea, although in this application and advanced BA system control is useful to try, and also achieved good results, but this is only the expansion of the application is not on the technology breakthroughs and innovations. As the technology further development, application and development of the converter will also be rendered more active phenomena, such as the matrix converter appears and the promotion and networking configuration of the inverter will become mainstream and synchronous motor frequency applications. While these trends are pushing further popularization of frequency converters and more widely used.

Reference documents
1 CAI Jing Luong. VAV system air-conditioning design Beijing: the Chinese construction industry press, 1997
2 Wu Jianping. design of VAV system-Shanghai University, 2007
3. electrical energy Guo Xiao rock and building energy conservation Beijing. intelligent electrical building technology, 2007-4