Small Disturbance Stability Analysis Of Permanent Magnet Wind Turbine

In recent years, wind energy gets a lot of attention of the world for itsinexhaustible, pollution-free advantages in the field of new energy. Due to theadvantages of high efficiency, simple structure, easy maintenance, low costs andelatively simple control system, permanent magnet wind power generator has becomeanother important wind generator which follows the double-fed induction andgradually begins to put into use, drawing more and more attention.When the small disturbance stability of permanent magnet is analyzed, accuratestudies can not be made if single mass shafting model are used,or full-power invertercontrol system and pitch control system are not considered. In this paper, on the basisof analysis of the structure and working principle of the permanent magnet windpower generator system, permanent magnet wind power generator and convertercontrol system model,maximum wind energy tracking, wind turbine and its doublemass shafting model, pitch system model are built.Then the signal model of thepermanent magnet wind turbine generator is derived. Oscillation modes and itsmechanism are analysed using eigenvalue analysis method.Permanent magnet wind power generation system can control the output powerby the way of controlling full converter. Low-frequency oscillation can be weaken sothat system can return to stabilizing operation.In addition,there is a phase lag in pitchcontrol system,and damping can be improved by phase angle compensation. On thebasis of the above, strategy of improving damping is proposed and system stabilizerof converter and PSS of pitch angle control system are designed. Finally thefeasibility of the programme is verified by eigenvalue analysis and time-domainsimulation.The results showed that the eigenvalues of oscillation modes obviouslyshift left, damping is enhanced after system stabilizer of converter and PSS of pitchangle control system were added.