Study Of Excitation Control System Of A.C. Excited Generator Based On DSP

There are more preponderance for Alternating Current Excited Generator (ACEG) than conventional synchronous generators in solving the over-voltage of high voltage power system and in constant frequency generation with variable speed, by using the three-phase alternating current excitation and adding the freedom of excitation control.It is the key point for ACEG playing good transient characteristics, agility and reliability of operation that using appropriate excitation control strategy. In this thesis, dual-passage excitation control strategy based on dynamical synchronous reference frame is studied according to the base theory and the voltage-current equation in steady state of ACEG. The modify excited control model is adopted in this system, considering that de-coupling of active and reactive power can not be realized completely because the accurate modal and generator parameters can not be obtained in practical application. The hardware of the excitation control system is designed using the dual-CPU project basing on the high speed DSP, considering the characteristics of digital signal processor chip TMS320VC5402 and TMS320LF2407 and the characteristics of this control system. The software of dual-passage excitation control strategy based on dynamical synchronous reference frame and control strategy of AC-DC-AC inverter are realized using the assembler program of TMS320VC5402 and TMS320LF2407. Different digital filters are designed in this system according to the characteristics of input signal in order to improve the stability and the reliability of the control system. The excited voltage or current harmonics of AC-DC-AC transducer and the stator voltage or current harmonics in the various condition are analyzed according to the experiment in No-load operation and load operation. Using the speed adjustment experiment and reactive power adjustment experiment, transient adjustment characteristics of ACEG are studied, dual-passage excitation control strategy based on dynamic synchronous reference frame is proved. It is useful to practical application for ACEG.