Research On The Control Technology Of Power Quality Disturbance Platform Based On ADRC

With the development of information technology,the domestic industrial production and various equipment to the power quality requirements are more and more high.According to the national standard,various power quality parameters are simulated accurately and in real time through the power converter,and the equipment is tested,which provides the basis for the power department to understand and solve the power quality problems.In this paper,power quality disturbance platform based on active disturbance rejection control(ADRC)is developed.In order to improve the anti-disturbance and decoupling performance of the platform,time-domain LADRC voltage control system was designed.In order to overcome the drawback that the closed-loop transfer function of the system has amplitude attenuation at high frequency,timefrequency voltage control system based on LADRC is designed.In order to further accelerate the updating speed of frequency domain control loop and improve the dynamic performance of the system,the FFT function is realized by using FPGA resources in DSP.In addition,by improving the tracking differentiator and state observer in LADRC,the tracking accuracy and stability are improved,which lays a foundation for the high order harmonics tracking control with high precision when there is no FFT or the non-integer harmonics need to be controlled.Finally,the effectiveness of the proposed strategy is verified by simulation and experiment.Firstly,the mathematical model of the inverter circuit in the two-phase synchronous rotating coordinate system is established,and the functions of the power quality disturbance platform are introduced.Then,time domain LADRC voltage control system including decoupling and disturbance rejection was designed by mathematical model.In order to overcome the drawbacks of the closed-loop transfer function of the system,such as amplitude attenuation and phase lag,time-frequency LADRC voltage control system was designed,the LADRC parameter tuning method is given,and their dynamic performance,steady-state performance and stability are analyzed by means of Bode diagram,then it is verified by simulation.In addition,the data transmission protocol program is written in DSP,and the FFT,BRAM and other timing driver modules are written in FPGA,so as to realize the FFT function by using the FPGA resources in DSP.The simulation results show that the conversion results of FFT IP cores are correct,and the dynamic performance of the system is better under the faster frequency domain loop updating speed.Then the tracking differentiator and state observer are improved and corrected,and the tracking differentiator and state observer based on trapezoidal method are derived to solve the problem of r limitation,which lays a foundation for the control of high order harmonics.At last,the hardware architecture design of double DSP+FPGA is described,and the time-frequency voltage control strategy and the functions of the power quality perturbation platform based on LADRC are verified by the experimental platform.Simulation and experimental results show that the time-domain LADRC voltage control strategy has better disturbance rejection performance than the double-loop PI control strategy.The time-frequency domain LADRC voltage control system can track reference value without static difference,and the real part and imaginary part can be decoupled,which has certain anti-disturbance ability.The power quality disturbance platform has high precision in each function.