Research And Design Of Digital APFC Based On Duty Cycle Predictive Method

With the enormous depletion of energy and the increasing crucial contaminate of air, to develop the electric vehicles, as a new type of transportation, has been a trend in today`s society. As the electric vehicle has been widespread, which may promote a need of high-power charging device, and it is going to bring a severe harmonic pollution to public electric net. So these devices are asked for equipping PFC(Power Factor Correction) module, which used for restraining harmonic electric, raising power factors, diminishing the public net`s pollution. Because the technology of digital control is increasingly mature, to digitize PFC has been one of the most investigative hotspots in electricity and electron.Presently, a good part of the APFC is transplanted from traditional control strategies, whose complicated arithmetic and large operational amounts are not helpful to the digitize PFC`s spread. So the advantage of digital control must be fully unleashed to work out an easy and truly suitable cyber operation for APFC. Dutycycle prediction, which is a kind of new nonlinear control strategy, is a valuable measure to solve the problem, for it`s simple computes and fast feedbacks.At first place, I run a detailed and theoretical inference to the current Duty cycle prediction whose operation is that the input voltage is directly pulled into itself. As a result, it is possible to interfere with the steady of the system. Consequently, I will introduce the input voltage filtering wave and feedback input voltage compensatory, as two progresses are added to the traditional basis. And built in Matlab of improved duty cycle control and average current control Boost-PFC system simulation diagram, the simulation results show that while the estimated duty cycle control get the samiliar power factor with the current average current control, the dynamic response speed is improved greatly, the algorithm is simpler, and the anti- interference ability is getting stronger.In the next place, system's hard ware can be achieved, when Boost-PFC electric circuit's technology standards and practice needs are assured, according to the design of system. Then I do an emulation test to the relevant circuit modules and optimize designed-parameters. In theory algorithm based on the completion of the process design software system, clear coding process.At last, according to the design of the system, the software and hardware experiment platform is built, and the related debugging work is completed. Through all the test datas, I can attest our designs meeting demands of arguments, by the way that wave forms of emulation and adjusted tests reflecting that flyback auxiliary power supply is stable at the both voltages, and its ripples are smaller. In other hand, duty cycle predictive control Boost-PFC system in a broad voltage input and output load and power factor are greater than 0.98, output DC bus voltage stability, and the algorithm execution time 66.8% of the average current control algorithm. Under the same conditions, the duty cycle control to obtain a power factor higher than the average current control about 1%, and fully embodies the advantages of the improved algorithm.