Regulating and equalizing DC capacitance voltages in multilevel STATCOM

Author

Chen, Yiqiang ; Mwinyiwiwa, Bakari ; Wolanski, Zbigniew ; Ooi, Boon-Teck

Author_Institution

Dept. of Electr. Eng., McGill Univ., Montreal, Que., Canada

Volume

12

Issue

2

fYear

1997

fDate

4/1/1997 12:00:00 AM

Firstpage

901

Lastpage

907

Abstract

Because of the high MVA ratings, it would be expensive to provide independent, equal, regulated DC voltage sources to power the multilevel converters which are proposed for STATCOMs. DC voltage sources can be derived from the DC link capacitances which are charged by the rectified AC power. This paper addresses two control issues: (1) regulation of the DC capacitance voltages and (2) their equalization. Equalization is necessary (i) to ensure the even sharing of voltage stresses in the gate-turn-off thyristors (GTOs), and (ii) to prevent the degradation of total harmonic distortion (THD) factors, as all harmonic elimination strategies depend on equal voltages in their assumptions. The strategies considered are: (a) the fundamental frequency method, and (b) the sinusoidal pulse width modulation method. Digital simulations are used to confirm the feasibility of the control methods

Keywords

PWM invertors; capacitance; harmonic distortion; power capacitors; power convertors; power systems; static VAr compensators; thyristor convertors; voltage control; DC capacitance voltages equalisation; DC capacitance voltages regulation; DC link capacitances; DC voltage sources; GTO inverter; THD degradation prevention; digital simulations; fundamental frequency method; gate-turn-off thyristors; harmonic elimination strategies; multilevel STATCOM; multilevel converters; rectified AC power; sinusoidal pulse width modulation method; static VAr compensator; total harmonic distortion degradation; voltage stresses sharing; Automatic voltage control; Capacitance; Capacitance-voltage characteristics; Degradation; Frequency; Pulse width modulation; Stress; Thyristors; Total harmonic distortion; Voltage control;

fLanguage

English

Journal_Title

Power Delivery, IEEE Transactions on

Publisher

ieee

ISSN

0885-8977

Type

jour

DOI

10.1109/61.584411

Filename

584411