US 9,813,054 B2
Semiconductor switching string
Colin Charnock Davidson, Staffordshire (GB)
Assigned to GENERAL ELECTRIC TECHNOLOGY GMBH, (CH)
Appl. No. 14/898,095
Filed by General Electric Technology GmbH, Baden (CH)
PCT Filed Jun. 10, 2014, PCT No. PCT/EP2014/062049
§ 371(c)(1), (2) Date Dec. 11, 2015,
PCT Pub. No. WO2014/198734, PCT Pub. Date Dec. 18, 2014.
Claims priority of application No. 13172036 (EP), filed on Jun. 14, 2013.
Prior Publication US 2016/0118907 A1, Apr. 28, 2016
Int. Cl. H02M 5/458 (2006.01); H03K 17/16 (2006.01); H03K 17/0814 (2006.01); H03K 17/10 (2006.01); H02M 5/45 (2006.01); H02M 7/68 (2006.01); H03K 17/66 (2006.01); H03K 17/687 (2006.01)
CPC H03K 17/161 (2013.01) [H02M 5/45 (2013.01); H02M 5/458 (2013.01); H02M 7/68 (2013.01); H03K 17/08144 (2013.01); H03K 17/105 (2013.01); H03K 17/16 (2013.01); H03K 17/66 (2013.01); H03K 17/687 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A semiconductor switching string, for use in a HVDC power converter, comprising:
a plurality of series-connected semiconductor switching assemblies, each semiconductor switching assembly having a main semiconductor switching element including first and second connection terminals between which current flows from the first terminal to the second terminal when the main semiconductor switching element is switched on, the main semiconductor switching element having an auxiliary semiconductor switching element electrically connected between the first and second connection terminals thereof; and
a control unit operatively connected with each auxiliary semiconductor switching element, the or each control unit being configured to switch on a respective auxiliary semiconductor switching element to selectively create an alternative current path between the first and second connection terminals associated therewith whereby current is diverted to flow through the alternative current path to reduce the voltage across the corresponding main semiconductor switching element, the or each control unit being further configured to switch on the said respective auxiliary semiconductor switching element when the voltage across the corresponding main semiconductor switching element differs from a real-time varying voltage reference equivalent to the average voltage across all of the main semiconductor switching elements in the semiconductor switching string, and the or each control unit being still further configured to control the amount of current diverted to flow through a respective alternative current path so that the voltage across the corresponding main semiconductor switching element approaches the real-time varying voltage reference.