Application Of Soft Switch Technology In Switching Power Supply And Harmonic Analysis

The quality of the electricity restricted the level of development of a modernindustrial country, in a large extent. Almost every country in the world paid more andmore attention to the electricity quality. Switch power supply solved the problemeffectively. But as the work frequency of the switch power supply higher and higher,the electromagnetic interference problem cannot be ignored. At present, through theuse of filter to solved the problem in engineering, the active power filter was usedwidely.First this paper presented a new type of switching power supply, with the softswitch technology, then analysed its working principle in detail. Secondly according tothe electromagnetic interference problem of the switch power supply, presented a newtype of three-phase four-wire active power filter, decreasd the number of the inverter,and analysed its working principle in detail, the inverter loss reduced a lot.And the useof improved methods of i_p-i_q detection circuit harmonic currents, this maked thecalculation time and unit costs fallen dramatically. Finally, studied the control methodof APF in-depth, according to the shortcomings of the Genetic algorithm and BPneural network algorithm, this paper presented the improved GA to optimize the BPneural network control algorithm, introduced catastrophe strategy. The simulationresults showed: The power factor of the system was improved from0.81to0.98, thecontrol system stability, neutral current was suppressed well, control algorithm fortraining the new error can meet the system requirements10^-4, and the training timewas only2.3082s.This paper presented a new type of switching power supply, the problem ofelectromagnetic interference was solved effectively，the power factor of the systemwas improved greatly, the training time was reduced, the harmonic of the system wasreduced. The new type of switching power supply was suitable for practice, had a certain practical significance.