This paper presents a nonlinear control scheme for back-to-back High Voltage Direct Current (HVDC) system based on feedback linearization control, using three-phase three-level voltage source converter. The design of the proposed nonlinear controller has been performed in a synchronous rotating reference frame (d-q) the aim to provide high dynamic performance, complete decouple control of active and reactive power and to maintain the DC bus voltage at its reference value.

The objective of maintaining balanced voltages in DC-link capacitors is achieved by using the three-level space vector modulation with balancing strategy based on the effective use of the redundant switching states of the converters voltage vectors. Finally, some simulations results are presented and discussed in order to verify and compared the feasibility and effectiveness of the proposed control scheme with the conventional controller (PI).