具動態迴路調變技術應用於改善暫態響應之功率因素校正器

Abstract

近年來,由於能源短缺的問題越來越嚴重,對電子產品而言,高可靠度及高效率成為相當重要的設計考量。功率因素校正電路可以調整電源供應器對交流電源所抽取的電流波形並且使其與輸入電壓同相位，因此可提升實功率的使用及達到高功率因素的效果。

一般而言，應用於中低瓦數產品，基於成本及效率的考量，功率因數校正電路常採用臨界導通的控制方式。由於輸入電源為交流電，經橋式整流過後的電壓波形頻率為120 Hz，並在輸出端形成120Hz的漣波電壓，為避免此電壓經由回授路徑影響到內部的控制訊號而造成功率因素低落，必須將功率因素校正系統的頻寬設計在小於20 Hz，以消除連波電壓的影響，達到功率因素校正的效果。然而，因為此系統頻寬的限制，當負載發生變化時，暫態響應的速度也因而被限制住，造成輸出電壓發生較大的過電壓的現象，並影響後級電路元件的使用壽命，降低系統的可靠度。

因此,本篇論文利用動態迴路調變的控制方式,可在負載發生變化時,自動調整系統頻寬,控制電感電流,加快暫態響應速度,以降低負載變化時輸出所產生的過電壓，提升系統的可靠度。測試電路以台灣積體電路製造股份有限公司點五微米800伏特超高壓製程來實現，量測結果功率因素可達到0.99,效率可達到95%,最大輸出功率可供應至90瓦特。當輸出負載變化由90瓦特至20瓦特及20瓦特至90瓦特時，暫態響應有著顯著的改善。

Due to the shortage of energy, high reliability and efficiency has become the focus of current green power systems. Power factor correction (PFC) can shape the input current of off-line power supplies in phase with the input AC voltage in order to increase the real power available from the AC source. Reliability of the Power Factor Correction (PFC) system is improved by fast transient response using the proposed adaptive loop modulation (ALM). Low bandwidth of less than 20 Hz that rejects AC source of 60/120 Hz coupling deteriorated system reliability in case of output load variation. The proposed ALM can automatically adjust bandwidth to rapidly increase or decrease inductor current in order to shorten transient response time. In steady state, system stability can be guaranteed by low-frequency compensation pole without being affected by ALM. The test circuit fabricated in TSMC 500V UHV LDMOS process demonstrated the performance of the highly-integrated PFC controller with the proposed ALM. Experimental results showed that the PFC system with ALM has high PF of 99%, high efficiency of 95%, and high power driving capability of about 90W. The improvement in transient response is faster than conventional PFC design with output load variation from 90 to 20W and vice versa