The working principle of the frequency converter is to convert the input AC power into DC power through a rectifier, and then convert the DC power into AC power through an inverter, and use a control circuit to adjust the output of the inverter to achieve control of the motor speed.
The frequency converter converts the input three-phase or single-phase AC power into DC power through a rectifier. This process is called rectification. The rectifier is usually composed of multiple diodes, which are turned on during the positive and negative half-cycles of the power supply to convert AC power into DC power. Then, the rectified DC power is smoothed by a filter to reduce voltage fluctuations and noise. The filter is usually composed of capacitors and inductors, which can absorb and release energy to make the DC power more stable. Next, the filtered DC power enters the inverter. The inverter consists of multiple transistors that switch in a certain way to convert DC power into AC power. The frequency, voltage and phase of the AC power output by the inverter can all be adjusted by controlling the switching state of the transistors.
The following are the main functions of the frequency converter
Motor speed control: The frequency converter can control the speed of the motor by changing the input frequency of the motor to achieve precise speed control. By adjusting the output frequency of the frequency converter, the speed of the motor can be smoothly adjusted to meet different speed requirements.
Energy saving and consumption reduction: By controlling the running speed and voltage of the motor through the frequency converter, the motor can be prevented from running at the rated speed under no load or low load conditions, thereby reducing energy waste and achieving energy saving.
Extending equipment life: The frequency converter can start and stop the motor smoothly, reduce the current impact during starting and stopping, reduce the mechanical wear of the equipment, extend the equipment life, and improve the reliability of the system.
Automation and intelligence: The frequency converter can accurately control the speed and operation mode of the motor according to the requirements of the production process, realize automated production, and improve product quality and production efficiency.
Grid regulation: In some cases, the inverter can be used as an auxiliary device of the power system to adjust the voltage and frequency of the power grid and improve the stability and reliability of the power grid.
Improve the working environment: By controlling the speed and operation mode of the motor through the inverter, mechanical vibration and noise can be reduced, the working environment can be improved, and production efficiency can be improved.
As a power control device, the inverter is widely used in industrial automation, energy and electricity, transportation, municipal engineering, commerce and home, etc., and plays a vital role in industrial production and commercial fields. Reasonable selection of inverters can not only improve production efficiency and product quality, but also save energy, reduce costs, and improve the working environment and equipment reliability.