Frequency converter is a power control equipment that uses frequency conversion technology and microelectronics technology to control AC motor by changing the working power frequency of the motor. Now many power equipment and places have the use of frequency converter, today take you to talk about what kinds of frequency converter.

There are many classification methods of inverter, according to the main circuit working mode classification, can be divided into voltage type inverter and current type inverter; According to the switching mode classification, it can be divided into PAM control inverter, PWM control inverter and high carrier frequency PWM control inverter. According to the working principle, it can be divided into V/f control frequency converter, slip frequency control frequency converter and vector control frequency converter. According to the classification of use, it can be divided into general inverter, high performance special inverter, high frequency inverter, single phase inverter and three phase inverter.

VVVF: Change voltage, change frequency CVCF: constant voltage, constant frequency. The AC power supply used in various countries, whether for homes or factories, has a voltage and frequency of 400V/50Hz or 200V/60Hz (50Hz), and so on. Usually, the device that converts the voltage and frequency fixed alternating current into the voltage or frequency variable alternating current is called "inverter". In order to produce variable voltages and frequencies, the device first converts the alternating current of the power supply into direct current (DC).

A frequency converter for motor control can change both voltage and frequency.

1, according to the transformation of the link classification:

It can be divided into AC-AC inverter, that is, power frequency AC is directly converted into frequency and voltage adjustable AC, also known as direct inverter; Ac-dc-ac inverter, it is the power frequency AC through the rectifier into DC, and then the DC into the frequency voltage adjustable AC, also known as the indirect inverter, is currently widely used general-purpose inverter.

2, according to the nature of DC power supply classification:

(1) Current-type inverter

The characteristic of current-type inverter is that the middle DC link uses large inductance as the energy storage link to buffer reactive power, that is, to choke the change of current, so that the voltage is close to sine wave, because the DC internal resistance is large, it is called current-source inverter (current-type). The characteristic (advantage) of current-type inverter is that it can suppress frequent and sharp changes in load current. It is often used in situations where the load current changes greatly.

(2) Voltage inverter

Voltage inverter is characterized by the middle of the DC link of the energy storage element using large capacitors, the load of reactive power will be buffered by it, DC voltage is relatively stable, DC power supply internal resistance is small, equivalent to the voltage source, so called voltage inverter, often used in the load voltage changes larger occasions.

In addition, the inverter can also be classified according to the output voltage regulation mode, according to the control mode, according to the main switch components, according to the input voltage level classification.