Modeling and Stability Analysis of AC-DC Power System with Controlled Rectifier and Constant Power Loads

-Power converters with their controls normally behave as a constant power load. This load can significantly degrade the system stability. Therefore, the system dynamic model is very importance because it can be used for stability analysis. It is well known that power converter models are time-varying because of their switching behaviours. This paper presents the DQ modeling method to eliminate the switching action to achieve time-invariant model for the stability analysis. The power system studied is the AC distribution system. The small-signal model of the power system is obtained by using a linearization technique. The small-signal simulations are used to validate the DQ linearized model. The reported model is then used for the stability analysis via the classical control theory. The results show that an excellent agreement between the mathematical model and the three-phase benchmark model is achieved. Key-Words: Constant power loads, DQ method, simulation, modeling, controlled rectifier, stability analysis