TUTCRIS - Tampereen teknillinen yliopisto


An online measurement method for common-mode impedance in three-phase grid-connected converters



Otsikko8th Annual IEEE Energy Conversion Congress & Exposition (ECCE 2016)
ISBN (elektroninen)978-1-5090-0738-7
DOI - pysyväislinkit
TilaJulkaistu - 2016
OKM-julkaisutyyppiA4 Artikkeli konferenssijulkaisussa
TapahtumaIEEE Energy Conversion Congress and Exposition -
Kesto: 1 tammikuuta 1900 → …


ConferenceIEEE Energy Conversion Congress and Exposition
Ajanjakso1/01/00 → …


Three-phase converters are common in modern power systems in interfacing of renewable sources and for improving power quality. A three-phase converter, whether operating as an inverter or active front-end, produces a varying common-mode voltage when conventional sinusoidal PWM is used. Frequency components of the common-mode voltage are located at the switching frequency which ranges usually from few kilohertz to tens of kilohertz and its multiples. The high-frequency AC component produces common-mode current which depends on the magnitude of common-mode impedance seen by the power converter. The common-mode current is usually mitigated by using common-mode chokes, complex passive filter topologies or active methods. The design of these filters is not straight-forward since the common-mode impedance is often unknown and may exhibit resonances. Therefore, an accurate method for measuring common-mode impedance is needed to enable deterministic filter design. Moreover, the common-mode impedance should be measured online, i.e., in the normal operating environment of the converter. In this paper an online method for measuring the common-mode impedance is proposed. The method can be implemented by using a converter which is able to achieve high switching frequency, such as an inverter based on SiC-switches.