Free running inverter supplying three=phase asynchronous motor - uses thyristors parallel to phase shift choke and antiparallel phase shift diode

摘要

A free-running inverter is used in the supply circuit of a three-phase asynchronous motor. The phase sequence of the inverter is achieved via a commutation network. The latter contains capacitors whose charges are reversed within a given period independently of the level of the load current. The commutating capacitors used for extinguishing the thyristors in the given phase sequence are decoupled from the load via lock diodes. Each thyristor (T) is connected in parallel with a series network consisting of a phase shift choke (L) and an anti-parallel phase shift diode (D).