Overcurrent Protection and Switching Aid For Power Darlington¿s: An Unique Approach

• Type: Article in International Conference Proceedings Book
• Date: 1989

Authors

António Quintas (Author) FEUP; António Pina Martins (Author) FEUP; José António Faria (Author) FEUP; Armando Araújo (Author) FEUP; José Machado da Silva (Author) FEUP

Conference proceedings International

Title: Third European Conference on Power Electronics and Applications

Third European Conference on Power Electronics and Applications

Aachen

Other information

Resumo (PT): This paper presents a new approach for overcurrent protection and switching aid of power darlington transistors used in UPS inverters. The approach come trough specific requirements and characteristics of UPS and power darlington transistors.It is noted that storage time and output transformer introduce low frequency distortion. The minimum output filter for this application was obtained for a switching frequency near 2kHz.At this level switching losses are smal when compared with total losses. This fact greatly simplifies the switching aid circuits, being possible to reduce it to a voltage clamp and a series inductance. The circuit reveals to be cost effective and reliable and uses only low performance/cost components. Experimental results are presented for a 40kVA UPS that was conceived at Porto University and is now manufactured by a portuguese company.

Abstract (EN): This paper presents a new approach for overcurrent protection and switching aid of power darlington transistors used in UPS inverters. The approach come trough specific requirements and characteristics of UPS and power darlington transistors.It is noted that storage time and output transformer introduce low frequency distortion. The minimum output filter for this application was obtained for a switching frequency near 2kHz.At this level switching losses are smal when compared with total losses. This fact greatly simplifies the switching aid circuits, being possible to reduce it to a voltage clamp and a series inductance. The circuit reveals to be cost effective and reliable and uses only low performance/cost components. Experimental results are presented for a 40kVA UPS that was conceived at Porto University and is now manufactured by a portuguese company.

Language: Portuguese

Type (Professor's evaluation): Scientific