Rectifier circuit: rectify 50HZ alternating current into direct current.

Frequency conversion circuit: Invert the rectified DC power into AC power with variable frequency.

Control part: Control the frequency of the alternating current output from the inverter circuit.

Protection circuit: protect the output from overcurrent and phase loss.

Display section: displays information such as inverter operating parameters and fault codes.

The frequency converter is a device that converts the power frequency power supply (50Hz or 60Hz) into AC power of various frequencies to realize the variable speed operation of the motor. Among them, the control circuit completes the control of the main circuit, the rectifier circuit converts AC power into DC power, the DC intermediate circuit smoothes the output of the rectifier circuit, and the inverter circuit inverts the DC power into AC power. For an inverter such as a vector control inverter that requires a lot of calculations, sometimes a CPU for torque calculation and some corresponding circuits are also required.

1. A rectifier, which is connected to a single-phase or three-phase AC power supply and generates a pulsating DC voltage.

2. The intermediate circuit has the following three functions:

a. Make the pulsating DC voltage stable or smooth for inverter use.

b. Power each control circuit through the switching power supply.

c. Filter or braking device can be configured to improve the performance of the inverter.

3. Inverter converts fixed DC voltage into AC voltage with variable voltage and frequency.

4. Control circuit, it transmits the signal to the rectifier, intermediate circuit and inverter, and it also receives the signal from these parts. Its main components are: output drive circuit and operation control circuit. The main functions are:

a. Use signals to switch semiconductor devices of the inverter.

b. Provide various control signals for operating the inverter.

c. Monitor the working status of the inverter and provide protection.