不連續/臨界導通模式升壓型功因校正器之線電流失真補償辦法

Abstract

本篇論文提出一種應用於具有零電流切換（zero current switching, ZCS）/零電壓切換（zero voltage switching, ZVS）/谷底切換（valley switching, VS）/切換頻率限制（switching frequency limitation, SFL）等功能之不連續導通模式/臨界導通模式升壓型功率因數校正器的失真線電流補償方法。此補償方法結合了傳統的變導通時間（variable on-time, VOT）控制以及平均電流（average current mode, ACM）控制以用於補償嚴重的輸入電流失真現象。另一方面，於本篇論文中，對於因零電流切換/零電壓切換/谷底切換/切換頻率限制等功能，以及市電端EMI濾波器所造成之線電流失真原因也具有詳盡的數學分析與解釋。一般而言，為了提升電源轉換器的效率，零電壓切換/谷底切換與切換頻率限制是必要的功能，但這些功能會使線電流失真更為嚴重。為了補償失真的電流，本篇論文提出一種基於平均電流控制之變導通時間（ACM-based VOT, ABVOT）控制方法。此外，一種基於定導通時間（constant on-time, COT）控制的取樣保持（sample and hold, S/H）方法也在本篇論文中提出，以取代傳統平均電流控制所需要的乘法器。另外，應用本論文所提方法的不連續導通模式/臨界導通模式升壓型功率因數校正器，其小訊號模型亦會被詳盡的分析以用來設計控制迴路的補償器。最後，透過電腦模擬與實作驗證本篇論文提出之方法的可行性及其性能。

A line current distortion compensation method is proposed in this dissertation for DCM/CRM boost PFC converter. This circuit features variable on-time (VOT) control, average current mode (ACM) control, and zero current switching (ZCS)/ zero voltage switching (ZVS)/ valley switching (VS)/ switching frequency limitation (SFL) functions. In order to increase efficiency, the ZVS/VS/SFL functions are usually needed, but in doing so, the line current is usually further distorted. In this dissertation, the mathematical analyses of the line current distortion caused by the DCM/CRM boost PFC converter with ZCS/ZVS/VS/SFL functions and the EMI filter are also conducted to account for the line current distortion. From the results of analyses, the ACM-based VOT (ABVOT) control for the DCM/CRM boost PFC converter is proposed. In addition, the noise-immunity sample-and-hold (S/H) approach of COT-based controller is proposed to replace the expensive multiplier which is usually needed for the conventional ACM-based control. The small signal model of the proposed circuit is also developed for the purpose of compensator design. The validity and the performances of the proposed ABVOT control with S/H approach is demonstrated by simulations and experimental results.