Research On Active Disturbance Rejection Control And Digital System For Static Synchronous Compensator

With the improvement of automation industry,the power customers are more and more particular about the power supply quality and dependability.Flexible AC Transmission System(FACTS) has been rapidly developed as an efficient technology to improve electric power quality.As one of the key technology of FACTS,Static Synchronous Compensator(STATCOM) has currently become a hot topic of the research on Flexible AC Transmission equipment because of its continuous adjustment of reactive current at depressed voltage,faster response,wide operating range,smaller size,lower harmonics and lower loss,etc.In this paper,the development of reactive compensation technology and the application of STATCOM at home and abroad are introduced first.The system structure and basic operation principle of STATCOM are investigated.Using input-output modeling approach and energy equations,a mathematical model is created for STATCOM in d-q two phase synchronous coordinates.And the stability performance is analysed according to the mathematical model.As the power system is a strong coupling nonlinear system and its loads are changing continually,the control method of Active Disturbance Rejection Controller(ADRC) is presented according to highly inherent nonlinear STATCOM which is disturbed and has variable parameters. Not only the basic principle of ADRC but also the structure and function of each part are studied deeply and systemically.According to this,a STATCOM control system based on ADRC is designed.The parameters of the control system are independent of the parameters of STATCOM system.So it has better adaptability and robustness. SVPWM modulation mode with which the DC voltage utilization ratio is high,the switch wastage is small and the harmonic content is low is adopted in producing the pulse wave.An experimental STATCOM system based on TMS320F2812 DSP is built which includes conditioning circuit,driving circuit,protecting circuit and so on.The program of the system is compiled.The simulation and experimental results show that STATCOM has good dynamic response and the reactive current is compensated to sinusoid with the same phase as source voltage rapidly.At the same time,DC voltage can reach a stable value rapidly.