A controller in d-q synchronous reference frame for hybrid HVDC transmission system

In this paper, a model-based controller is proposed for Hybrid HVDC transmission systems. Hybrid HVDC comprises a Line-commutated Converter (LCC) and a Voltage Source Converter (VSC) which are connected on the same DC link. The VSC regulates the active and reactive power using a model-based controller in a synchronous reference frame while the LCC maintains the DC voltage using a proportional and integral controller. PSCAD/EMTDC simulations illustrates the performance of the Hybrid operation in comparison with CIGRE benchmark HVDC model during normal operation and severe disturbance such as DC fault and AC faults.