The reactor in the circuit generally has two functions:
(1) to suppress the surge (voltage, current); (2) to suppress the harmonic current.
Reactor in the use of the frequency converter is divided into input reactor, output reactor and DC reactor. Different reactor on the role of the inverter is also different.
input reactor
To limit the voltage mutation and switching overvoltage caused by electric shock, contained in the smooth supply voltage spikes, or smooth bridge rectifier circuit commutation voltage defects, effectively protect converter and improve the power factor. It can not only prevent the interference from the power grid, and reduce the pollution of harmonic current of rectifier unit on the grid.
output choke
The main function is to compensate the influence of the distribution capacitance of the long line (20-200m), reduce the leakage current of the electric motor, and can restrain the output harmonic current, increase the output high frequency impedance, and effectively restrain the dv/dt. To reduce the high frequency leakage current, to protect the frequency converter, reduce the role of equipment noise.
DC reactor
Connected between the inverter system of DC rectifier and inverter, the main purpose is will be limited in a specified value of superimposed on the DC current of the AC component and maintain current rectifier continuous, decreasing the current pulse value, the inverter operation more stable and improve the power factor of inverter.
