Can energy-saving inverters really save energy and power?

2021-10-27 08:26:05 jact_elec

Can energy-saving inverters really save energy and power?

Frequency converter is a power control device that uses frequency conversion technology and microelectronics technology to control AC motors by changing the frequency of the motor's working power supply. The frequency converter is mainly composed of rectifier (AC to DC), filtering, inverter (DC to AC), braking unit, drive unit, detection unit, micro-processing unit, etc.

  • The energy-saving principle of industrial inverter

1. Energy saving by adjusting the speed

In order to ensure the reliability of production equipment, industrial enterprises have a certain margin of drive capacity compared with the design load.

Therefore, many motors do not run under full load, and the excess torque increases the consumption of active power and causes a waste of electrical energy.

For this situation, the speed control function of the inverter can reduce the running speed of the motor, so that the motor can maintain a constant voltage while reducing power consumption.

2. Energy saving through dynamic adjustment of efficiency

The measurement and control output function of the inverter itself continuously monitors load changes, and quickly makes adjustments to adapt to the load changes, so that the motor output always maintains high efficiency.

3. Energy saving through V/F function

Under the condition of ensuring the output torque of the motor, the frequency conversion itself can automatically adjust the V/F curve, reducing the output torque of the motor and reducing the input current, thereby achieving the purpose of energy saving.

4. Energy saving through soft start function

As we all know, when the motor is started at full voltage, according to the motor's starting torque requirement, the current drawn from the grid is about 7 times the rated current of the motor.

If the starting current is large, it will not only waste electricity, but also produce greater fluctuations in the grid voltage. The continuous fluctuation of the power grid will also increase the line loss and transformation loss.

Through the soft start function of the inverter, the motor starting current can gradually rise from 0 to the rated current of the motor, effectively alleviating the impact of the starting current on the grid, not only reducing

the waste of large current power, but also reducing the significant impact of starting inertia on the equipment Impact reduces equipment life loss.

5. Energy saving by improving power factor

Most of the three-phase asynchronous motors are inductive loads, because the motor absorbs a large amount of reactive power during operation, resulting in a low power factor.

After adopting the inverter, its characteristic becomes: AC-DC-AC. After the rectification and filtering process of the inverter, the impedance characteristic of the inverter to the grid is resistive, which improves the power factor and reduces the reactive power loss.

In summary, the inverter does have certain energy-saving effects on many occasions, and even the effect is extremely significant on some occasions. Therefore, as an excellent technological innovation, frequency converter is fundamentally worthy of vigorous promotion.

  • The misunderstanding of energy saving and power saving of frequency converter

Due to the vigorous advancement of frequency conversion technology and the vigorous promotion of frequency converter vendors, some industrial enterprises have subconsciously equated the use of frequency converters with energy saving.

However, in actual use, due to different situations, many companies have gradually discovered in practice that not all places where inverters are used can save energy and electricity.

So what causes this situation and what misunderstandings people have about inverters?

1. The inverter can save electricity when used on all types of motors

Whether the variable frequency speed regulator can save electricity is determined by the speed regulation characteristics of its load.

For centrifugal loads, fans, and water pumps, the loads are quadratic torque loads to meet the motor output power P∝Tn, P∝n3, that is, the output power on the motor shaft is proportional to the cube of the speed.

It can be seen that for the quadratic torque load, the power saving effect of the frequency converter is the most prominent.

For constant torque loads, such as Roots blowers, the torque has nothing to do with the speed. Generally, an air outlet is set to be controlled by a valve.

When the air volume exceeds the demand, the excess air volume is discharged to achieve adjustment.

In this case, speed regulation can be used, and the effect of power saving can also be achieved.

In addition, for constant power loads, power has nothing to do with the speed. In these cases, there is no need to use the inverter.

2. As an electronic circuit, the inverter itself also consumes electricity

It can be known from the composition of the frequency converter that the frequency converter itself has an electronic circuit, so it consumes power during operation.

Although it consumes less power compared to a high-power motor, its power consumption is an objective fact.

  • Summary

To sum up, it is a fact that the inverter has power-saving function when running at industrial frequency, but its preconditions are:

1. High power and load for fans and pumps;

2. The device itself has power saving function (software support);

3. Long-term continuous operation. These are the three conditions for the inverter to show the power saving effect.

Energy saving and consumption reduction is the eternal goal and purpose of JACT inverter company. Therefore, the inverter must be used rationally to truly realize the strategy of energy saving and consumption reduction and sustainable development.