A novel approach to select HVDC - controller parameters by using a decoupling filter

Abstract

Abstract. This paper presents a novel strategy on how to design a sophisticated HVDC controller by using a decoupling filter. At first a simple mathematical model of the HVDC system will be derived. The HVDC is a multivariable system; hence the rectifier and inverter voltages and currents are coupled and therefore it is not trivial to design a controller for one converter station without taking the influence of the opposite converter into account. Subsequently this paper will show how to eliminate this coupling in a mathematical way and as a consequence it will be presented how a controller and its appropriate parameters will be determined. The novel controller will be compared with a standard PI controller of a HVDC system and therefore the dynamic behaviour will be obtained.

Generic modeling of a line commutated HVDC system for power system stability studies

“…Firing angles of the rectifier and inverter are influencing both the direct current and the direct voltage. Applying control design to such systems is quite difficult; one opportunity offers the simplification by the usage of a decoupling filter [11].…”

“…Changes in the firing angle will not apply immediately to the HVDC system due to the firing delay of 60° on average for six-pulse units and 30° on average for twelve-pulse units [11]. This firing delay equals a dead time element and has to be added to the HVDC model.…”