FIRING CIRCUIT FOR SERIES-CONNECTED CONTROLLED SEMICONDUCTOR RECTIFIERS

• US 3,593,038 A
• Filed: 08/15/1966
• Issued: 07/13/1971
• Est. Priority Date: 08/13/1965
• Status: Expired due to Term

• Current Assignee: Boksjo Carl Ingvar, Hylten-Cavallius Nils, Lindblad Sven Erland
• Original Assignee: Boksjo Carl Ingvar, Hylten-Cavallius Nils, Lindblad Sven Erland
• Inventors: HYLTEN-CAVALLIUS NILS, BOKSJO CARL INGVAR, LINDBLAD SVEN ERLAND
• Application Number:
  US04/572,250
• Time in Patent Office: 1,793 Days
• US Class Current: 307/117
• CPC Class Codes: H02M 1/088 for the simultaneous control of series or parallel connected semiconductor devices
• CPC Class Codes: H02M 1/096 the power supply of the control circuit being connected in parallel to the main switching element H02M1/092 takes precedence

Abstract

A chain of series-connected semiconductor rectifiers has a voltage divider connected in parallel therewith. A firing circuit is connected on the one hand to the control electrode and to one of the main electrodes of each rectifier and on the other hand to two different points on the voltage divider. The firing circuit derives a control voltage between such points, which is fed to the rectifier by a switching means, such as an optically controlled semiconductor.

Claims

1. In a chain of series-connected semiconductor controlled rectifiers having a voltage divider connected in parallel to said rectifier chain, each rectifier having a control electrode and at least one main electrode and firing circuit connected to the control electrode and one of the main electrodes of said rectifier on the one hand and on the other hand to two different points on the voltage divider, said firing circuit comprising means to derive a control voltage from the voltage between said points on the voltage divider and switching means for connecting said control voltage to the control electrode, thereby firing the rectifier, said means to drive a control voltage comprising a rectifying means connected to said points on the voltage divider and a capacitor connected to said rectifying means, said capacitor being also connected to said switching means, said voltage deriving means including a transformer, said transformer having input and output terminals, said input terminals being connected to said two points on the voltage divider, at leaSt one of said output terminals being connected to said rectifying means.

2. A firing circuit according to claim 1, the polarity of said transformer and of said rectifying means being so selected as to cause the capacitor to be charged during the reverse blocking intervals of said semiconductor controlled rectifiers.

3. A firing circuit according to claim 1, said rectifying means being a full-wave rectifying means having its AC terminals connected to said points of said voltage divider and its DC terminals connected to said capacitor.

4. In a chain of series-connected semiconductor controlled rectifiers having a voltage divider connected in parallel to said rectifier chain, each rectifier having a control electrode and at least one main electrode and a firing circuit connected to the control electrode and one of the main electrodes of said rectifier on the one hand and on the other hand to two different points on the voltage divider, said firing circuit comprising means to derive a control voltage from the voltage between said points on the voltage divider and switching means for connecting said control voltage to the control electrode, thereby firing the rectifier, said means to derive a control voltage comprising a rectifying means connected to said points on the voltage divider and a capacitor connected to said rectifying means, said capacitor being also connected to said switching means, a transformer, said transformer having input and output terminals, at least one of said input terminals being connected to said switching means, one of said output terminals being connected to said control electrode.