A model-based controller in rotating reference frame for Hybrid HVDC

Abstract

In this paper, a model-based controller is proposed for Hybrid HVDC, Hybrid comprising a Voltage Source converter (VSC) using in the sending side and Line-commutated Converter (LCC) using in the receiving side. This type of HVDC may be applied when power is only in one direction for example HVDC for offshore wind farm applications. VSC controls directly the instantaneous active and reactive power using a synchronous reference frame controller while the LCC maintains the DC voltage using a proportional-integral (PI) controller. It also proposed in this paper, when AC grid is weak, to replace the LCC for a capacitor commutate converter (CCC) because of the additional commutation voltage reduces the risk of commutation failure. PSCAD/EMTDC simulations are provided to illustrate the performance of the proposed controller under normal operation and severe disturbance such as three phase-to-ground AC and DC faults.