The motor inverter is a device that converts a commercial power supply (50 Hz or 60 Hz) into an AC power of various frequencies to realize variable speed operation of the motor. The control circuit completes the control of the main circuit, the rectifier circuit converts the alternating current into direct current, the direct current intermediate circuit smoothes the output of the rectifier circuit, and the inverter circuit inverts the direct current into alternating current. For motor inverters such as vector-controlled motor inverters that require a large amount of calculations, a CPU for torque calculation and some corresponding circuits are sometimes required.
Rectifier circuit: rectify 50HZ AC to DC.
Frequency conversion circuit: Inverts the rectified DC power into a variable frequency AC power.
Control section: Controls the frequency of the AC output from the inverter circuit.
Protection circuit: Protects the output from overcurrent and phase loss.
Display section: Display information such as inverter operating parameters and fault codes.
1. A rectifier that is connected to a single-phase or three-phase AC power source to produce a pulsating DC voltage.
2. The intermediate circuit has the following three functions:
a. Make the pulsating DC voltage stable or smooth for use by the inverter.
b. Power the various control lines through the switching power supply.
c. Filter or brakes can be configured to improve motor drive performance.
3. Inverter converts a fixed DC voltage into an AC voltage of variable voltage and frequency.
4. A control circuit that transmits signals to the rectifier, intermediate circuit, and inverter, and it also receives signals from these parts. Its main components are: output drive circuit, operation control circuit. The main functions are:
a. A signal is used to switch the semiconductor device of the inverter.
b. Provide various control signals for operating the motor frequency converter.
c. Monitor the working status of the motor inverter and provide protection.