Research On Anti Interference's Theories And Methods Of Test System Driven By The Mode Of Servo And Frequency Conversion

Stability and reliability are the most important technical indicators which are taken to evaluate performance of test systems and also the weakest part compared with similar products of developed countries. Especialy after high accurate equipments replace traditional AC motors with servo motors and frequency conversion motors, we realize controllability. Simultaneously, the problem of serious interference comes forth.In this paper, the anti-interference's theory and the method of testing system which is driven by the mode of servo and frequency conversion are studied, and the formation principles and propagation paths of interference source in theory are analyzed, simultaneously those common anti-interference measures are optimized and improved. The systemic anti-interference method on hardware and software is proposed based on the analysis of interference. On hardware, for strong electric circuit, the proper distribution and parameters of power filter, reactor and controlled servo motor (or transducer) are applied to weaken interference source and destroy propagation paths combining with anti-interference methods such as optical isolation, shielding, earthing technique and anti-jamming designing of PCB board. Finally, interference signals can be minimised and eliminated. On software, wavelet analysis algorithm, which is used to filter and reduce the noise of signals, is adopted. We may apply comparative trade-off and wavelet algorithm to is also applied to complete reading feedback data and to realize protection of important data and stability of communication between the system and outside equipments and programmer's intelligent diagnoses.The dSPACE simulation controlling system as research platform is adopted, and corresponding mathematical models such as cascade PID controller, low-pass filter, servo route's location loop, speed loop and current loop according to the composition of system are established. The control parameters of the models including cascade PID controller, filter, location loop, speed loop, current loop and every loop's feedback gains whose number adds up to seventeen can be adjusted based on the online testing ability of dSPACE. Test system's working performance and parameters are optimized by watching transmission signal's waveform.The simulation results show that the proposed measures on hardware and software enhance system's stability and ability of anti-interference, and the effects are greatly obvious.