CS253408B1 - Switching choke with ferrite supersaturation insert - Google Patents

Abstract

The ferrite inductive commutating choke is intended for use in power semiconductor converters. The space of the air gap has a ferrite insert that provides the required nonlinear course of the inductance to current, t. j. large inductance for small currents and vice versa, low inductance for large currents. Ferrite insert choke considerably reduces commutation overload on the drive elements, which allows classic surge protection to be removed.

Description

BACKGROUND OF THE INVENTION The present invention relates to a commutating choke with a ferrite supersetting insert for power semiconductor converters. It solves the problem of contradictory requirements for commutating chokes at different times in the switching event of semiconductor converters.

So far, known designs of commutating chokes are of two types. The first type is a choke with constant inductance for the entire working range - linear. Its inductance must be as small as possible so that the converter reliably commutes at low commutation voltages. However, this means that the current in the tripped thyristor decreases with considerable steepness, resulting in a large current surge in the downstream direction, a large commutating charge of the element, and considerable prepatients on the tripped thyristor, which must be limited by additional circuits.

The second type is a choke with a nonlinear inductance course - a clamp. This type of choke complies with the requirements, thus having a large inductance for low current values and very low inductance for large currents. However, today used corsets are usually designed as a conductor through several ferrite rings. A disadvantage is that in order to achieve a large initial inductance, it is necessary to considerably increase the number of ferrite rings, or the number of wire guides through the rings, which is both disadvantageous in construction.

The above-mentioned drawbacks are eliminated by a commutating choke with a ferrite supersaturation insert according to the invention, the principle of which is that in the iron core of the choke a ferrite supersetting insert of the same and the same

Claims (1)

OBJECT Commutating choke with ferrite supersaturation liner, characterized in that in the iron core (1j is in the air space 4 or smaller cross section than the cross section of the iron core. The commutating choke according to the invention has a large inductance for small currents and a small inductance for large currents, so no Fig. 1 shows a commutating choke according to the invention in Fig. 1. In the air gap of the iron core of the choke 1, a ferrite supersetting insert 2 is inserted with a cut of the same or less The inductance of the commutating choke for small currents is given by the number of winding turns 3 and the magnetic properties of the closed magnetic circuit, and after the ferrite insert is saturated, the magnetic circuit behaves as if there is an air gap in place of the ferrite insert. Depending on the current size, the inductance h can be influenced by the choice of material and the geometric dimensions of the ferrite superset. Advantageous features of the choke of the invention can also be used to modify the already produced linear commutating chokes by replacing the spacer insert inserted into the choke air gap with a ferrite insert without additional choke design. In this case, the unnecessary protective circuits for the thyristors of the inverter can be disconnected. The use of the inventive choke in place of the rectifier input chokes greatly reduces the influence of the semiconductor converter on the network and simplifies its interference suppression. BRIEF DESCRIPTION OF THE INVENTION The gaps placed by the ferrite supersaturation liner (2, 1 sheet of drawings 253408