Research On A Novel Sliding Mode Control Of Shunt Active Power Filter

Firstly for illustrating the APF system is the affine nonlinear system, this thesis introduces the basic working principle of active power filter and establishes its discrete model.In order to effectively control capacitor voltage of the DC side, instantaneous energy balance mathematical model is established.Through the analysis of the instantaneous reactive power test, it’s found that the low pass filter is the main reason affecting the harmonic detection. The traditional low pass filter cannot deal with the problem of nonlinear satisfactorily. This paper adopts the neural network adaptive low pass filter to obtain DC component of the active and reactive current. The traditional voltage control of DC side mainly adopts PI control. Although PI control method is relatively simple and reliable, it still has some defects.The reference voltage is obtained by drooping the grid voltage and current in order to overcome the shortcoming of the traditional DC voltage control. Because drop regulator cannot guarantee the system stability during regulating voltage, the adaptive backstepping control strategy is used to solve this problem.The sliding mode control is used as the control strategy of active power filter, which has good robust but sometimes exists chattering. In this paper, neural network is used to continuously update the parameters of sliding mode control. This paper designs system structure diagram of active power filter.Finally this paper builds the simulation model of active power filter to obtain the fundamental wave, harmonic and load current waveform through MATLAB/Simulink simulation. Compared with the waveform got by traditional control method, the feasibility of the improved control algorithm is verified.Based on the simulation, designing hardware circuit and software of the system with the main control chip of DSP TMS320F28335. The experiment results verify the feasibility and effectiveness of the proposed theory.