Deadbeat Control Based Three-level Active Power Filter System And Parameter Identification

Power electronic has wider application in various fields. However, as a typical non-linear load, power electronic devices will cause harmonic pollution and decline power quality and bring inconvenience to relevant areas of electricity. Active power filter(APF) is a dynamic tracking filtering device, which is essential on occasions of high power quality. Currently, APF research focus contain high power, good dynamic tracking performance, reliable long-term high-accuracy filtering. Accordingly, the paper select NPC three-level topology for the study, and research APF system with high dynamic performance and chronic high accuracy effect. Main contents are as follows.Firstly, the paper introduced subject background and significance and research status. So that the APF research focus are elicited and the research work is confirmed.Secondly, APF work principle are described. And then, the instantaneous reactive power harmonic detection method is confirmed as system harmonic detection scheme. Using moving window integration algorithm to extract active and reactive current DC traffic. Simulation verification: instantaneous reactive power harmonic detection has fast dynamic speed based on moving window integration low-pass algorithm. Low-delay harmonic extraction scheme could provide basis to high-performance APF system.Thirdly, after the analysis of the mathematical model of three-level APF, carrier PWM and space vector PWM are analyzed. And the paper introduced three-level APF DC side midpoint potential balance control based on charge balance.Fourthly, deadbeat compensation current tracking control principle are clarified by three-level APF mathematical model analysis. And the paper proposed a application scheme: deadbeat control system use equidistant nodes Newton backward difference interpolation prediction and its repeat correction control, to achieve transient command current forecast. Compared simulation shows superiority of this system deadbeat control scheme: it has faster transition speed under system start-up and load mutation situation. And deadbeat PWM modulation control could achieve higher filtering accuracy.Fifthly, the paper proposed that limited memory recurrence least squares could be used to achieve APF resistance and inductance online identification. Data saturation can be eliminated. Simulation shows superiority of the proposed APF identification method: it has better peformance under chronic time-varing situation. Online identification on aging reactor parameter could ensure long-term effective of APF high filtering accuracy.Finally, MC56F8345 DSP as the core to the three-level APF system hardware and software design of main parts are analyzed. The experiment debugging were conducted in the built three-level APF system prototype. Paper accomplished expetiment result analysis of instantaneous reactive power harmonic detection based on moving window integration low-pass and deadbeat current tracking control.