Since its appearance on the market, inverter technology has made great strides in features and performance. These devices are increasingly used in many different industries. So what exactly are inverters used for? What are the applications of inverters in the industry? Please follow the article below for the answer.
What is the inverter used for?
In the previous article on the topic “What is an inverter?” Nam Phuong Viet defined for you: An inverter is an electronic device that regulates the speed and torque of an alternating current (AC) motor. The inverter performs this function by changing the frequency and voltage supplied to the motor.
Or it can be understood in the opposite direction: The inverter is used to change the frequency of the power supply to the motor to achieve two purposes: changing the speed and adjusting the torque of the motor.
However, if the inverters only stopped at changing frequency and voltage, there would not be a need for so many lines and models of inverters to be born, right? In actual production and life, users need more functions in an inverter than just changing frequency and voltage.
Along with the development of science and technology, many lines of inverters with advanced features have been developed and put into production and life. These types of inverters bring a lot of value and benefits to businesses.
Adjust engine speed
Motor speed control is one of an inverter’s main and core functions. However, many methods can be implemented to change the motor’s speed effectively. However, an inverter is still considered the most stable, efficient, and energy-saving solution.
The inverter performs this function by changing the power supply frequency to the motor to control the rotation speed, meeting different load requirements. It helps the motor operate flexibly and is suitable for each specific application (such as conveyor belts, pumps, and fans…).
During your studies of electric motors as a student, you must have come across this expression:
N= 60f (1-s)/p
Where:
- s is the motor slip coefficient
- p is the number of pole pairs of the motor
- f is the frequency of the current supplied to the motor
From the above expression, it can be seen that 3 methods can change the motor speed, including changing s, p, or f. However, changing s and p is often ineffective and does not save the business electricity. Therefore, the most effective way is to change the f value; the inverter is a perfect device to solve this problem.
Some specific motor speed control applications you may encounter are conveyors, pumps, fans, air compressors, elevators, etc.
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Engine torque control
In addition to the main function of adjusting the speed of the AC motor, the inverter is also capable of effectively changing the motor torque because the torque is proportional to the square of the voltage amplitude and the frequency of the voltage supplied to the motor.
In most inverter devices, pulse width modulation (PWM) is applied, changing the AC voltage amplitude and adjusting the motor torque.
The inverter uses the following methods to control the motor torque:
- V/F Control: This is the most common torque control method, in which the voltage and frequency are adjusted in a fixed ratio to maintain the magnetic flux.
- SVC Control: This method independently adjusts the voltage and frequency to optimize the motor torque at each specific speed.
- DTC (Direct Torque Control) Control: This method directly controls the motor torque and speed using sensors and advanced control algorithms.
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Engine protection
The leading causes of damage or severe damage to the motor are overload, overvoltage, overheating, power short circuit, phase loss, and voltage drop (low voltage). If these causes are not handled promptly, they can damage the motor.
Most inverters are integrated with protection modes such as overcurrent, overload, overheating, phase loss, and short circuits through continuous monitoring of motor parameters such as current, voltage, frequency, and temperature. When these parameters exceed the allowable threshold, the inverter will activate relays or switches to cut off the circuit, protecting the motor.
For this reason, using a frequency converter also helps increase the durability and life of the motor, reducing the risk of damage and maintenance costs.
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Improve engine performance
Inverters bring many benefits to the engine, contributing to significantly improving the engine’s operating efficiency.
As Nam Phuong Viet mentioned in previous articles, the inverter provides stable and precise motor control. Thanks to that, the motor operates more smoothly according to the power demand.
This helps reduce engine noise and voltage loss due to the engine running at unstable frequencies while increasing engine life due to the inverter’s protection features.
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Soft-start
Soft-start is one of the important functions of the inverter, helping to control the motor starting process smoothly and safely.
When the motor starts directly (hard start), the current can increase 5-7 times the rated current. This causes a voltage drop on the grid, affecting other equipment. When using an inverter, it will adjust the frequency from 0 Hz gradually to the nominal frequency (usually 50Hz or 60Hz). At this time, the motor speed increases slowly and smoothly, avoiding causing jerks or mechanical shocks.
Benefits of using frequency converters in the industry
Inverters play a significant role in modern industry, bringing many practical benefits to production and business activities. Including:
Increase work efficiency and productivity
The inverter allows the motor speed to be changed step lessly and precisely from 0 to the maximum speed of the motor. Thanks to that, the operator can adjust the motor speed to suit the specific requirements of the production process, improving work efficiency and product quality.
The inverter helps the motor start and stop smoothly, reduces noise and vibration, and protects the motor against overcurrent, overload, overvoltage, overheating, voltage drop, etc.
In addition, due to rectification through diodes and capacitors, the reactive power from the motor is very low (Some inverter lines, such as Yaskawa U1000 and CR700, have a Cos φ coefficient of 0.98). It helps save costs for 3-phase capacitors and reduces power loss.
Improve product accuracy and quality
The inverter allows precise motor torque adjustment, helping to control the force acting on the product during the processing. Therefore, the product is made with higher precision and quality, especially in precision mechanics and machine manufacturing applications.
Increased flexibility and automation
Suppose you have ever worked in a manufacturing company. In that case, you will have witnessed many production stages that, if wholly or partially automated, will help improve performance and productivity and optimize costs for the business.
Inverters can be used for various industrial applications, from simple applications such as conveyor control to complex applications such as industrial robot control.
Because they are designed to be easily integrated into automation systems, allowing automatic control and monitoring of engine operations, this helps improve production management and operation efficiency.
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Energy saving
The inverter controls frequency and voltage to adjust the motor speed to match the load requirements. Instead of running at a fixed speed (100%), the motor will operate at the most efficient level for each application. This helps to reduce energy consumption significantly.
This effect is most noticeable in applications such as pumps, fans, or compressors, where the load changes frequently. According to the Affinity Law in pump and fan systems, when the rotational speed is reduced by 50%, the power consumption can be reduced by up to 87.5%.
In addition, with the soft start function, the inverter also effectively reduces energy loss during the start-up process while increasing system life.
Some high-end inverter lines, such as Yaskawa D1000 and U1000 inverters, can regenerate energy during braking and have a high power factor. This helps improve the system’s power factor, reduce reactive currents, and reduce pressure on the grid.
So Nam Phuong Viet has gone through all the knowledge content “What is the inverter used for? The importance of inverters in industries”. Hopefully, this content is helpful to you.
Nam Phuong Viet is also researching and applying many automation solutions for different applications. Interested readers can contact Nam Phuong Viet directly to discuss and directly consult on suitable solutions for your business.
