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Energy Saving Solutions Energy-saving solutions for devices suck the wind blowing, smoke, steam ...

Energy-saving solutions for devices suck the wind blowing, smoke, steam ...

In the factories, mills and power plants are in a vacuum airflow devices, smoke, steam ... using three-phase AC motor as the primary engine. At other firms, usually cooling equipment (central air conditioner), water pumps ...

In the process of production and traffic of these devices always need to change to suit the specific needs of production enterprises and factories .... The engine is the primary three-phase alternating current motor, adjusting the flow of these devices is difficult because as we know, the flow of fluid through the device is dependent on the speed the primary motivation. To the structure of the three-phase alternating current motor, the traditional rotation of engine speed as a constant with the electric grid ac frequency f = 50Hz industrial relations through f = "pn/60" - where p is the number of motor pole pairs, and n is the rotational speed. With this relationship, the rotational speed of the engine depends only on the frequency of the grid. So to make traffic changes, the best thing is to change the primary engine speed, which means to change the frequency of the grid. Furthermore, as we know, for the transmission pump and fan, load torque depends on the speed of rotation axis as a function of the square. Flow out of the system is proportional to rotational speed:

Meanwhile, the capacity of the system required by the multiplication between the torque and rotational speed:
P = M x n

Therefore, requires the capacity of the system is proportional to the cube of rotational speed and is also proportional to the cube of the flow:

That by adjusting the frequency of the grid is not possible, so far in the enterprise, the plant often to adjust the volume, people often use measures to adjust the shield inputs as a way out or back. For example in thermal power plants, in the hood fan, blowing wind, in the output or input of the fan, usually a shield, it includes the wing blade, a shaft rotating in the radius. There is a small motor controls the rotation of the shield, to create wide or narrow the gap depending on the requirements for the wind, the smoke passes through. The air flow control smoke this type of deal is effective but adjust the flow of smoke because the wind but not the economic engine is still working almost unchanged, power consumption is not reduced much. Line drawings of the following characteristics would indicate that.

Obviously, the above methods, the energy consumption of the whole system much larger than the energy required to flow down requirements, rather than design. Despite the reduced flow, the energy consumption but also reduced the loss of control devices such as the shield is still large. The adjustment method showed different shield on the shield losses also vary greatly. The loss on the loss of this barrier suggests a huge potential savings.

As I said above, the flow of these devices depends on the speed of the primary motor, but this speed depends on the frequency of the power source. So with a primary engine has, the speed adjustment is most easily done is to change the frequency of the power source. The solution to this problem is to use the inverter to replace the valve.
According to the traditional technology previously only available to new inverter at higher frequencies, with small capacity in the broadcasting industry and television. But with industrial frequency and with large capacity of hundreds of kilo watt is not performed.

So far, barriers to technological level has been removed, the countries with advanced technology have made the power inverter, and immediately applied to production, resolution the problem of adjusting the speed of three phase AC motors provide high performance and economically.

The adjustment of output (eg traffic) of the pump / fan shall be made immediately at the input is the source of traffic, is also adopted to adjust the speed of the engine and transmission pump / fan did. When not using valve (or valves to open the maximum available) of course will not damage the van. The engine was not born on the shaft capacity of greater demand on resistance to win the van.

In the figure 2 is the energy curve - frequency of traffic compared to the control input shield. Two properties on the street, we always find the energy curve for the inverter system when used (MICROMASTER) to control is much lower than the valve characteristics, especially when adjusted traffic down the price low percentage. As in the figure, if the flow reduction to 20%, energy consumption will decrease by nearly 50% over the value plan designed to shield the input control. When using the inverter to reduce energy consumption by only 2-3%. When the flow of consumption fell 50%, energy consumption frequency with only 15% compared with 56% using the input shield.

Just compare that to shield the controller output, the power consumption also saves a lot better.

Also, with the use of shields, not only the energy loss caused huge waste which itself also causes no harm to the system small. The shield is worn away very quickly. The mechanical details on the system is under pressure more than necessary, more rapid fatigue and perishable. Thus, we also take additional costs for system maintenance.

So inverter work like?

Working principle of the inverter is quite simple (Figure 5). First, power 1pha or 3-phase AC is rectified and filtered into one-dimensional flat source. This stage is done by diode bridge rectifier and capacitors (capacitor DC link). Thus, the power factor of the system cosphi frequency counts and not depend on the load value at least 0.96.

This voltage is converted (reverse flow) of 3-phase AC voltage symmetry. This stage is now done through IGBT (transistor insulated gate bipolar) by means of pulse width modulation (PWM). Thanks to technological advancement of microprocessor and semiconductor technologies current power, switching frequency can be up to pulse frequency range of ultrasound to reduce engine noise and reduce losses in the iron core motors.

System voltage 3-phase AC output, can change the value of the amplitude and frequency levels depending on the controller. In theory, the frequency and voltage is a certain rule depending on control mode. For constant torque load, the voltage ratio - the frequency is constant. However, with the load pump and fan, this rule is a function of type 4. Voltage as a function of frequency of type 4. This creates torque characteristic is quadratic function of speed in accordance with the requirements of the load pump / fan torque by itself is also a quadratic function of voltage.

Power conversion efficiency of the inverter is very high because of the use of power semiconductor devices manufactured by modern technology. Therefore, energy consumption is approximately equal to the energy required by the system.
Through calculations with real data, with the actual costs with a primary engine of 100 kW, the time for recovery of capital investment is a frequency range from 3 months to 6 months.

Currently in Vietnam there were some factories use this inverter and the results were obvious. With energy saving measures in addition to improving the control system, the inverter is now considered a standard application for transmission to the pump and fan.

Thanks to high-tech features with the most modern control technology (optimal control for energy) is the inverter and will satisfy many investors in the country, in the region and the world.