Yq. Chen et Bt. Ooi, STATCOM based on multimodules of multilevel converters under multiple regulation feedback control, IEEE POW E, 14(5), 1999, pp. 959-965
This paper describes a STATCOM based on diode-clamped multilevel converters
. The current rating is increased by parallel connections of multiple conve
rter modules, The gate-turn-off thyristor (GTO) switching angles of the fun
damental switching strategy are exploited in the design to accomplish three
objectives: I) low total harmonic distortion (THD) in voltages and current
s; 2) equal sharing of the currents in the individual modules; and 3) direc
t control of ac voltage magnitude. Three proportional-integral (P-I) feedba
ck loops are employed for the purposes of: 1) regulating the total de volta
ges and ensuring the quadrature relationship of the ac currents and voltage
s; 2) regulating the reactive power drawn by the STATCOM; and 3) equalizing
the de capacitor voltages in all the levels.