DocumentCode :
110282
Title :
Determining the Value of DC-Link Capacitance to Ensure Stable Operation of a Three-Phase Photovoltaic Inverter
Author :
Messo, Tuomas ; Jokipii, Juha ; Puukko, Joonas ; Suntio, T.
Author_Institution :
Dept. of Electr. Eng., Tampere Univ. of Technol., Tampere, Finland
Volume :
29
Issue :
2
fYear :
2014
fDate :
Feb. 2014
Firstpage :
665
Lastpage :
673
Abstract :
Grid interfacing of photovoltaic generators using three-phase inverters offers the advantage of constant power flow allowing smaller capacitance values to be used in the dc-link compared to single-phase inverters. Electrolytic capacitors, used in the dc-link, are often considered to decrease reliability. Reliability could be improved by using film capacitors, but their usage is limited by high cost and low capacitance. Much research has been done to minimize the dc-link capacitance value, particularly, in the field of drives and wind turbines. It has been shown that motor drive in regenerative mode contains a right-half-plane (RHP) pole in its control dynamics having a significant effect on the required dc-link capacitance. The RHP pole can cause instability as has been observed in wind turbine applications. Photovoltaic inverters have been reported to suffer from instability of the dc-link-voltage control, but the origin of the observed problems is poorly understood. This paper shows explicitly that an RHP pole is present in the control dynamics also in photovoltaic inverters affecting the minimum required dc-link capacitance. The paper proposes a minimum value for the dc-link capacitance that is required for stable operation. Design rules are given for single- and two-stage inverters. Moreover, it is shown that a source having constant power output effectively removes the RHP pole from the dc-link-voltage control dynamics.
Keywords :
electrolytic capacitors; invertors; photovoltaic power systems; power generation control; power generation reliability; power grids; stability; wind turbines; DC-link capacitance value; DC-link-voltage control dynamics; RHP pole; constant power flow; constant power output; electrolytic capacitors; film capacitors; motor drive; photovoltaic generators; photovoltaic inverter; power grid; reliability; right-half-plane pole; three-phase photovoltaic inverter; two-stage inverters; wind turbine application; Capacitance; Capacitors; Frequency control; Generators; Inverters; Motor drives; Voltage control; DC-link capacitor; frequency response; photovoltaic; small-signal model; three-phase inverter; two-stage inverter;
fLanguage :
English
Journal_Title :
Power Electronics, IEEE Transactions on
Publisher :
ieee
ISSN :
0885-8993
Type :
jour
DOI :
10.1109/TPEL.2013.2255068
Filename :
6488862
Link To Document :
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