應用搭配平均計算公式之鋸齒波取樣策略於全數位化功率因數修正 器之實現

Applying Saw-Toothed Wave Sampling Strategy with Average Calculation Formula to Fully-Digitalized Implementation of PFC Converter

陳漢威(Hen-Wei Chen)

指導教授 ： 胡國英

國立臺北科技大學/電資學院/電機工程系所/碩士(2009年)

摘要

眾所皆知，全數位化功率因數修正(Power Factor Correction, PFC)修正器之主要缺點在於實現的過程中需要多個類比數位轉換器(Analog-to-Digital Converter, ADC) ，而一顆高性能的ADC價格昂貴。因此，本論文所提之取樣策略係藉由一高速成對鋸齒波(Saw-Toothed Wave)與所感測之訊號比較以產生回授所須之數位取樣值，除此之外，並針對功率因數修正的應用場合，提出一平均電流計算公式並搭配變換取樣點策略來對功率因數修正器之平均輸入電流進行正確的取樣，其中，基於平均電流計算公式中所計算出的電感電流激磁斜率計算值可衍生出另一無感測輸入電壓計算公式來獲取輸入電壓的大小以供給前饋機制使用，除此之外，控制器所須之正弦參考命令乃利用所提之零點偵測配合正弦表(Sinusoid Table)來產生。另一方面，輸出電壓之訊息亦藉由一近似平均計算公式來求得。因此系統內部完全不需要加入任何ADC即可實現全數位化功率因數修正整流器。最後，藉由模擬與實驗波形驗證了所提方法於功率因數修正整流器取樣之可行性與有效性。

關鍵字

Active-HDL ； 功率因數修正器 ； FPGA ； 數位控制 ； PFC

並列摘要

As generally recognized, the main drawback of a fully-digitalized power-factor- correction (PFC) converter is that too many analog-to-digital converters (ADCs) are used, and hence the corresponding cost is high. Therefore, in this thesis, the information on the required signal is obtained via two paired saw-toothed waves compared with the sensed signal, without any ADC used. For the PFC applications, two proposed formulas used to figure out the average current, together with the strategy for changing sampling points, are applied to accurately sampling the average input current of the PFC converter. At the same time, based on the slope value of the magnetizing inductance current obtained from the average current calculation formula, another formula used to calculate the input voltage is derived so as to obtain the input voltage information used to feed the partial feedforward controller. As for the sinusoidal reference command, it is generated by zero detection along with a sinusoid table. On the other hand, the information on the output voltage is obtained by one approximation average calculation formula. Therefore, there is no ADC required to realize fully-digitalized control of the PFC converter. Furthermore, the feasibility and effectiveness of the proposed sampling topology are verified by simulated and experimental results.

並列關鍵字

Active-HDL ； PFC ； FPGA ； Digital Control ； PFC

參考文獻

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