METHOD FOR CONTROL OF A VOLTAGE STIFF FUNDAMENTAL-FREQUENCY COMMUTATED CONVERTOR AND CONVERTOR EQUIPMENT WITH MEANS FOR CARRYING OUT THE METHOD

摘要

Convertor equipment comprises a voltage stiff self-commutated and fundamental-frequency commutated convertor (SR) for connection to an alternating voltage network (N) and a direct voltage network (DP, DN, C). The equipment comprises path-determining members (FCC) adapted, based on the measured direct voltage (uD) of the convertor and a frequency reference (fbus), to determine characteristic data ( psi hex) of an estimated polygon path (HDEK) for a flux reference vector ( psi ref), reference vector forming members (FCC) adapted, based on a phase angle reference arg ( psi ref), to form a flux reference vector ( psi ref) following this path, and commutation-controlling members (FCC) adapted to trigger the next commutation at such a time that the flux reference vector and the flux vector of the convertor will coincide at the point of intersection (C) between the path (A1, GC) of the flux vector and one side (EK) of said polygon path, which side has a direction which deviates from the direction of that polygon side (HD) along which the flux reference vector moves immdiately prior to the commutation.