為深入了解基于UC3854A控制的PFC變換器中的動力學特性,研究系統參數變化對變換器中分岔現象的影響,在建立Boost PFC變換器雙閉環數學模型的基礎上,用Matlab軟件對變換器中慢時標分岔及混沌等不穩定現象進行了仿真。在對PFC變換器中慢時標分岔現象仿真的基礎上,分析了系統參數變化對分岔點的影響,并進行了仿真驗證。仿真結果清晰地顯示了輸入整流電壓的幅值變化對系統分岔點的影響。
Abstract:
In order to better understand the dynamics characteristic of power factor correction converter based on UC3854A, and make the way that parameters change influences the bifurcation phenomena of the system clearly. The math model of the two closed loop circuits to the Boost PFC (Power Factor Correction) converter controller was built. Then, with the help of Matlab, the simulation for nonlinear phenomena such as chaos and slow-scale bifurcation in the PFC converter was made. Finally the factors that have influence to the phenomenon of bifurcation under slow-scale in PFC converter were analyzed. The simulation results clearly show the parameters change influences the bifurcation point of the system.
針對UHF讀寫器設計中,在符合EPC Gen2標準的情況下,對標簽返回的高速數據進行正確解碼以達到正確讀取標簽的要求,提出了一種新的在ARM平臺下采用邊沿捕獲統計定時器數判斷數據的方法,并對FM0編碼進行解碼。與傳統的使用定時器定時采樣高低電平的FM0解碼方法相比,該解碼方法可以減少定時器定時誤差累積的影響;可以將捕獲定時器數中斷與數據判斷解碼相對分隔開,使得中斷對解碼影響很小,實現捕獲與解碼的同步。通過實驗表明,這種方法提高了解碼的效率,在160 Kb/s的接收速度下,讀取一張標簽的時間約為30次/s。
Abstract:
Aiming at the requirement of receiving correctly decoded data from the tag under high-speed communication which complied with EPC Gen2 standard in the design of UHF interrogator, the article introduced a new technology for FM0 decoding which counted the timer counter to judge data by using the edge interval of signal capture based on the ARM7 platform. Compared with the traditional FM0 decoding method which used the timer timed to sample the high and low level, the method could reduce the accumulation of timing error and could relatively separate capture timer interrupt and the data judgment for decoding, so that the disruption effect on the decoding was small and realizd synchronization of capture and decoding. Testing result shows that the method improves the efficiency of decoding, at 160 Kb/s receiving speed, the time of the interrogator to read a tag is about 30 times/s.