Special frequency converter supplier reminds you: Why use a frequency converter when replacing the equipment's matching motor with a frequency converter motor? What kind of changes will frequency converter power supply bring to motor applications? Here is a brief discussion on frequency converters for motors, analyzing how frequency converters have brought disruptive changes to motor applications.
Overview of frequency converters for motors
There are roughly three types of frequency converters for motors
Ordinary functional type
The basic v/f frequency conversion speed regulation function can be met for general applications with low requirements for speed regulation accuracy and torque control performance.
High functional type
V/F variable frequency speed regulation with torque control function is commonly used for constant torque loads in elevators.
Vector control or direct torque control type
High performance applications such as steel rolling and papermaking that require high dynamic performance must use vector control frequency converters.
Application of frequency converter
In the era when frequency converter technology was not yet mature, high-performance applications such as fans and water pumps were mostly equipped with variable pole multi speed three-phase asynchronous motors. However, due to the stepped speed regulation, it was not possible to achieve wide range smooth speed regulation, let alone performance optimization. Nowadays, frequency converters are widely used, and frequency conversion motors specifically designed for loads such as fans and pumps can maintain high levels of electrical performance such as efficiency and power factor throughout the entire speed range through design optimization.
Three level jump of load or output regulation for fans, pumps, etc
Traditional adjustment methods. By adjusting the opening of the inlet or outlet baffle and valve to regulate the air and water supply, the input power is high and a large amount of energy is consumed in the interception process of the baffle and valve.
Variable pole multi speed three-phase asynchronous motor with graded speed regulation. When operating at full load, the variable pole multi speed three-phase asynchronous motor runs at high speed; When the air volume or water supply needs to be adjusted, the motor switches to medium or low speed operation, resulting in a significant reduction in input power and achieving extremely significant energy-saving effects.
Variable frequency speed regulation for three-phase asynchronous motors with stepless speed regulation. When using variable frequency speed regulation, if the flow rate requirement is reduced, the requirement can be met by reducing the speed of the pump or fan. Usually, the dedicated variable frequency motor for this application has optimized performance indicators over a wide speed range, with a consistently high ratio of "flow rate/energy consumption".
Soft start and permanent magnet synchronous frequency conversion application
Asynchronous motors are driven by frequency converters, which not only achieve stepless speed regulation, but also control the starting current of the motor within a range of less than twice the rated current, and the starting torque can reach about twice the rated torque. Therefore, there is no starting problem for three-phase asynchronous motors driven by frequency converters, and high-performance soft start is their inherent characteristic.
High performance permanent magnet synchronous motors, such as new energy vehicle specific permanent magnet motors and ship drive permanent magnet motors, are all driven by frequency converters. Such applications typically use frequency converters as highly integrated specialized drive power modules, which are manufactured in an integrated manner with the motor body to form a permanent magnet synchronous motor system.
Variable frequency drive has expanded the application fields of motors, breaking many design taboos, such as low-speed direct drive wind turbines as low as tens or hundreds of revolutions, high-speed direct drive spindles as high as tens of thousands of revolutions, and specialized motors for automotive drives. With the upgrading of applications and the continuous refinement of professional requirements, frequency converters for motors will inevitably develop towards multi-dimensional directions such as high-performance universal, specialized electromechanical integration, and intelligent advanced applications, promoting the continuous innovation and upgrading of motor design concepts and motor manufacturing.