201025804 六、發明說明： 【發明所屬之技術領域】 本發明是有關於一種取樣方法，特別是指一種應用於 電壓轉換系統的取樣方法。 【先前技術】 參閱圖1，兩級轉換器已普遍應用於具功因修正（p〇wer Factor Correction，PFC)之交流 / 直流轉換器（ac dc Converter)中。第一級轉換器91為升壓型功因修正器，採取 © 雙迴路的平均電流控制（Average Current Control)模式，控制 電路90取樣輸入電壓匕、輸入電流&與第一輸出電壓匕而 產生的脈寬調變訊號Λ/,可控制第一級轉換器91之功率開關（ 圖未示），而第二級轉換器92則為降壓型轉換器，採取單迴 路的電壓模式控制，控制電路90取樣第二輸出電壓L而產 生的脈寬調變訊號％可控制第二級轉換器92之功率開關（ 圖未示）。 在習知取樣技術t，控制電路90需要發出中斷向量 ❹ （INT)以中斷主程式，以分別對輸入電壓ρς、輸入電流（、 第一輸出電壓G及第二輸出電壓G進行取樣後進行類比/數 位轉換並經過適當的運算產生脈寬調變訊號批、％。整個 系統中具有三個控制迴路需要進行取樣’也就是說必須有 三個不同的中斷訊號，才可獲得各自對應的迴路頻寬。如 此不僅系統在電路設計上繁瑣複雜，也降低了整體的工作 效率。 【發明内容】 3 201025804 因此，本發明之目的，即在提供一種可以提高工作效 率且程式簡潔易讀的電壓轉換系統的取樣方法。 於是，本發明電壓轉換系統的取樣方法是包含： (a) 令該控制模組在該脈寬調變訊號的責任週期中點附 近對該輸入電壓、輸入電流及輸出電壓進行取樣；及 (b) 令該控制模組根據對該輸入電壓、輸入電流及輸出 電壓的取樣結果產生該控制訊號。在本發明步驟（a)中，該 輸入電壓、輸入電流及輸出電壓在該脈寬調變訊號的責任 週期中點附近依序或同步被取樣。 本發明藉由上述取樣方法所能達成之功效在於不需額 外的中斷訊號，只需在脈寬調變訊號的責任週期中點附近 對所有訊號進行取樣，進而獲得各自所須的迴路頻寬，使 得程式簡潔易讀且系統工作效率更佳。 【實施方式】 有關本發明之别述及其他技術内容、特點與功效，在 以下配合參考圖式之一個較佳實施例的詳細說明中，將可 清楚的呈現。 參閲圖2,本發明電壓轉換系統之較佳實施例包含一電 廢轉換模組1、-控制模組2及—脈寬調變模組3。在電壓 轉換模组1中，第-級轉換器u根據電源輸人電壓^，及 對應該輸入電壓匕的輸入電流&進行電壓轉換以產生第一輸 出電壓1而第二級轉換器12収利用第—輸出電壓^進 行電壓轉換產生第二輸出電壓L。 。 脈寬調變模組3輕接於電壓轉換模組i，並根據控制模 201025804 、叫去分別控制電壓轉換模組1 所。十算出的控制訊號L^分別產生脈寬調變訊號 的第一級轉換器11及第 二級轉換器12進行電壓轉換。 控制模組2耦接於電壓轉換模組1與脈寬調變模組3， 控制模組2主要包括有201025804 VI. Description of the Invention: [Technical Field] The present invention relates to a sampling method, and more particularly to a sampling method applied to a voltage conversion system. [Prior Art] Referring to Fig. 1, a two-stage converter has been commonly used in an AC/DC converter (ac dc converter) with a power factor correction (PFC). The first stage converter 91 is a boost type power factor corrector, and adopts a double current average current control (Average Current Control) mode, and the control circuit 90 samples the input voltage 匕, the input current & and the first output voltage 匕The pulse width modulation signal Λ / can control the power switch of the first stage converter 91 (not shown), and the second stage converter 92 is a buck type converter, adopting a single loop voltage mode control, control The pulse width modulation signal % generated by the circuit 90 sampling the second output voltage L can control the power switch of the second stage converter 92 (not shown). In the conventional sampling technique t, the control circuit 90 needs to issue an interrupt vector INT (INT) to interrupt the main program to sample the input voltage ρς, the input current (the first output voltage G, and the second output voltage G, respectively). /Digital conversion and appropriate calculation to generate pulse width modulation signal batch, %. There are three control loops in the whole system that need to be sampled 'that is, there must be three different interrupt signals to obtain the corresponding loop bandwidth. In this way, not only the system is cumbersome and complicated in circuit design, but also reduces the overall working efficiency. [Abstract] 3 201025804 Therefore, the object of the present invention is to provide a voltage conversion system that can improve work efficiency and is simple and easy to read. The sampling method of the voltage conversion system of the present invention comprises: (a) causing the control module to sample the input voltage, the input current, and the output voltage near a midpoint of the duty cycle of the pulse width modulation signal; And (b) causing the control module to produce a sample based on the input voltage, input current, and output voltage In the step (a) of the present invention, the input voltage, the input current, and the output voltage are sequentially or synchronously sampled near the midpoint of the duty cycle of the pulse width modulation signal. The present invention is performed by the above sampling method. The effect is that no additional interrupt signal is needed, and all signals are sampled near the midpoint of the duty cycle of the pulse width modulation signal, thereby obtaining the required loop bandwidth, making the program simple and easy to read and working systematically. The present invention will be clearly described in the following detailed description of a preferred embodiment of the present invention with reference to the accompanying drawings. The preferred embodiment of the voltage conversion system of the present invention comprises an electric waste conversion module 1, a control module 2 and a pulse width modulation module 3. In the voltage conversion module 1, the first stage converter u is based on The power input voltage ^, and the input current & corresponding to the input voltage 匕 are voltage-converted to generate the first output voltage 1 and the second-stage converter 12 receives the first-output voltage ^ for voltage conversion The second output voltage L is generated. The pulse width modulation module 3 is lightly connected to the voltage conversion module i, and is separately controlled according to the control mode 201025804, and the voltage conversion module 1 is separately controlled. The ten calculated control signals L^ are respectively generated. The first stage converter 11 and the second stage converter 12 of the pulse width modulation signal perform voltage conversion. The control module 2 is coupled to the voltage conversion module 1 and the pulse width modulation module 3, and the control module 2 mainly includes Have
一類比/數位轉換器21、一與類比/數 器22轉接的除法器23、一循環計數器 器22、一與數位訊號處理 卜數器24、一與除法器23 矛循環》十數器24柄接的比較電路25❹其中循環計數器24 ® 肖脈寬調變訊號叫同步計數且其計數週期與脈寬調變訊號 Μι的週期對應（相同）。 對第一級轉換器U來說，控制模組2會在脈寬調變訊 號踔的責任週期（duty cycle)中點附近對感測到的輸入電壓π 、輸入電流匕及第一輸出電壓G進行取樣，並利用數位訊號 處理器22進行計算產生控制訊號。同理，對第二級轉換 器12來說，控制模組2則是在脈寬調變訊號鳩的責任週期 中點附近對感測到的第二輸出電壓匕進行取樣，並利用數 ❿ 位訊號處理器22進行計算產生控制訊號心n2。以下將詳細 說明控制模組2進行訊號取樣及產生控制訊號心的過 配合參閲圖3和圖4，本發明電壓轉換系統的取樣方法 的較佳實施例包含以下步驟：A type of ratio/digital converter 21, a divider 23 with an analog/digital converter 22, a loop counter 22, a digital signal processing counter 24, and a divider 23 spear loop "10" The comparison circuit 25 of the handle is in which the cycle counter 24 ® modal signal is called synchronous counting and its counting period corresponds to the same period of the pulse width modulation signal Μι. For the first-stage converter U, the control module 2 senses the input voltage π, the input current 匕, and the first output voltage G near the midpoint of the duty cycle of the pulse width modulation signal 踔. Sampling is performed and a digital signal processor 22 is used for calculation to generate a control signal. Similarly, for the second stage converter 12, the control module 2 samples the sensed second output voltage 附近 near the midpoint of the duty cycle of the pulse width modulation signal ,, and uses the number of bits. The signal processor 22 performs calculations to generate a control signal heart n2. The following is a detailed description of the control module 2 for signal sampling and the generation of a control signal center. Referring to Figures 3 and 4, a preferred embodiment of the sampling method of the voltage conversion system of the present invention comprises the following steps:
由於取樣第一級轉換器U之輸入電壓匕、輸入電流^ 及第一輸出電壓G與取樣第二級轉換器12之第二輸出電壓 G相同’故以下將只以取樣第一級轉換器U之輸入電壓P 201025804 、輪入電流&及第一輪出電壓^來說明。 步驟51 ’在系統—開始運作時，數位訊號處理器22在 起始時間^產生一預設的控制訊號L給脈寬調變模組3。 步驟52，脈寬調變模組3根據控制訊號產生脈寬調 變訊號岣，此時，脈寬調變訊號蛑的工作脈波寬度阶為 責任週期），同時控制訊號被送入除法器23中使 其產生相當於脈寬調變訊號叫的工作脈波寬度灰的一半寬 度％的數值iv並輸入給比較電路25。 步驟53，因此，脈寬調變模組3開始產生（輸出）脈寬調 變訊號衅的下一週期且循環計數器24重新計數，當循環計 數器24計數到數值#時，比較電路25會產生一觸發訊號& 去觸發類比/數位轉換器21對感測到的輸入電壓π、輪入電 流h及第一輸出電壓G進行取樣及類比/數位轉換，藉此使 得類比/數位轉換器21取樣的時間點恰好是在脈寬調變訊號 踔的責任週期中點户或中點p的附近。 步驟54,接著類比/數位轉換器21將取樣且數位化後 的輸入電壓訊號G、輸入電流訊號及第一輸出電壓π送給 數位訊號處理器22進行計算，以產生下一個控制訊號給 脈寬調變模組3，使據以決定脈寬調變訊號軋的下—個週期 之工作脈波寬度妒。因此，步驟52到步驟54將在脈寬調變 訊號Μ的每個被產生的目前波形週期中被重複執行以決 定脈寬調變訊號蚌下一波形周期的工作脈波寬度所，而使數 位訊號處理器22可以藉由控制訊號回授控制脈寬調變模 組3適時調整脈寬調變訊號Λ/,的工作脈波寬度所。 201025804 - 同理，針對脈寬調變訊號竓，亦可藉由上述方式，控 制類比/數位轉換器21對脈寬調變訊號軋進行取樣以回授控 制脈寬調變訊號竓的工作脈波寬度。 由上述說明可知，本實施例藉由在脈寬調變訊號的 責任週期中點附近取樣，可以減少雜訊的干擾增加取樣 結果的精確度。 而且，輸入電壓G、輸入電流匕及第一輸出電壓G可以 在脈寬調變訊號衅的責任週期中點ρ附近被類比/數位轉換 Φ 器2丨依序或同步地取樣。 因此，數位訊號處理器22會從取樣後的時間點到脈寬 調變訊號蛑的下一個週期開始前計算出控制訊號 ，如此才可以決定脈寬調變訊號蛘、鹎的下一個週期之: 作脈波寬度F以及決定取樣的時間點户。換言之，本發明利 用上述數位控制即可獲得取樣各訊號時所需的迴路頻寬， 而可以不需額外利用中斷訊號對所需訊號進行取樣，，如 此不僅可以提高系統的工作效率，而且可以使設計出來的 Φ 控制程式更為簡潔易讀。 此外，本較佳實施例中，數位訊號處理器22對於第一 轉換電路11之控制原理是將數位化之第一輸出電壓^與第 一參考電壓匕相減，所得之誤差訊號“經由電壓控制單元 (Voltage C〇ntr〇ller) 221可得一參考訊號& ;然後將數 位化後的輸入電壓訊號G與前述之參考訊號、相乘後得到 電流命令Ve/，接著，將數位化後的輸入電流訊號屯與電流 命令W相減後之誤差訊號k送入一電流控制單元222 ;該電 201025804 流控制單tl 222 ( Current Controller )採用平均電流（ Average Current)控制模式，是將所得之誤差訊號c經由比 例-積分控制器及脈寬調變模組3以產生脈寬調變訊號砵； 平均電流控制模式可迫使輸入電流波形追隨輸入電壓波形 ，使得功率因數儘可能地趨近於單位功因。 數位訊號處理器22對於第二轉換電路12之控制是採 單迴路控制’其將數位化之第二輸出電壓G與第二參考電 壓匕π相減’所得之誤差訊號Ver2經由電壓回授控制單元（ Voltage Feedback Controller) 223採用電壓控制模式並經脈參 寬調變模組3’產生脈寬調變訊號从2。其中，電壓控制單元 221、電流控制單元222及電壓回授控制單元223之參數值 如表一所示。 表一 控制類別 KP ki 電壓控制單元 0.5 0.0003 電流控制單元 1.0 0.5 電壓回授控制單元 0.01 0.05 綜上所述，本發明電壓轉換系統的取樣方法，藉由控 制模組2直接在前一脈寬調變訊號的責任週期中點附近分 別對第一級轉換器11及第二級轉換器12之輸入訊號及輸出 訊號進行取樣，再對取樣結果進行數位訊號處理，以在該 前一脈寬調變訊號的週期内，計算出下一個脈寬調變訊號 的責任週期，如此不僅不需要額外的中斷訊號，提高電壓 201025804 · . 轉換減仏作效率，也使得程式在設計上更為簡潔。 惟以上所述者，僅為本發明之較佳實施例而已，當不 能以此限定本發明實施之範圍’即大凡依本發明申請專利 範圍及發明說明内容所作之簡單的等效變化與修飾，皆仍 屬本發明專利涵蓋之範圍内。 【圖式簡單說明】 圖1是一電路方塊圖，說明習知的兩級轉換器系統； 圖2是一系統方塊圖，說明本發明之較佳實施例；及 Ο 圖3是一流程圖’說明本發明電壓轉換系統的取樣方 法0Since the input voltage 匕, the input current ^ and the first output voltage G of the sampling first-stage converter U are the same as the second output voltage G of the sampling second-stage converter 12, the following will only sample the first-stage converter U. The input voltage P 201025804 , the wheel current & and the first round of output voltage ^ to illustrate. Step 51 ’ When the system is in operation, the digital signal processor 22 generates a predetermined control signal L to the pulse width modulation module 3 at the start time. Step 52: The pulse width modulation module 3 generates a pulse width modulation signal 根据 according to the control signal. At this time, the working pulse width of the pulse width modulation signal 蛑 is a duty cycle, and the control signal is sent to the divider 23 The value iv corresponding to half the width % of the working pulse width gray called the pulse width modulation signal is generated and input to the comparison circuit 25. Step 53, therefore, the pulse width modulation module 3 begins to generate (output) the next cycle of the pulse width modulation signal 且 and the cycle counter 24 recounts. When the cycle counter 24 counts the value #, the comparison circuit 25 generates a The trigger signal & de-trigger analog/digital converter 21 samples and analog/digitally converts the sensed input voltage π, the wheeled current h, and the first output voltage G, thereby causing the analog/digital converter 21 to sample The time point is just in the vicinity of the point or midpoint p in the duty cycle of the pulse width modulation signal. Step 54: The analog/digital converter 21 then sends the sampled and digitized input voltage signal G, the input current signal and the first output voltage π to the digital signal processor 22 for calculation to generate the next control signal for the pulse width. The modulation module 3 is configured to determine the working pulse width 妒 of the next period of the pulse width modulation signal rolling. Therefore, steps 52 to 54 are repeatedly executed in each generated current waveform period of the pulse width modulation signal 以 to determine the pulse width of the pulse width modulation signal 蚌 next waveform period, and the digits are made. The signal processor 22 can control the pulse width modulation module 3 to adjust the working pulse width of the pulse width modulation signal Λ/, by controlling the signal feedback. 201025804 - For the same reason, for the pulse width modulation signal 竓, the analog/digital converter 21 can be controlled to sample the pulse width modulation signal roll to feedback the working pulse wave of the control pulse width modulation signal 藉. width. As can be seen from the above description, in the present embodiment, by sampling near the midpoint of the duty cycle of the pulse width modulation signal, the interference of the noise can be reduced to increase the accuracy of the sampling result. Moreover, the input voltage G, the input current 匕, and the first output voltage G can be sampled sequentially or synchronously by the analog/digital conversion Φ 2 in the vicinity of the duty cycle ρ of the pulse width modulation signal 。. Therefore, the digital signal processor 22 calculates the control signal from the time point after the sampling to the start of the next cycle of the pulse width modulation signal ,, so that the next cycle of the pulse width modulation signal 蛘, 鹎 can be determined: The pulse width F and the time point at which the sampling is determined. In other words, the present invention can obtain the loop bandwidth required for sampling each signal by using the above digital control, and can sample the required signal without using the interrupt signal additionally, thereby not only improving the working efficiency of the system, but also enabling The designed Φ control program is simpler and easier to read. In addition, in the preferred embodiment, the digital signal processor 22 controls the first conversion circuit 11 by subtracting the digitized first output voltage ^ from the first reference voltage ,, and the resulting error signal is "via voltage control." The unit (Voltage C〇ntr〇ller) 221 can obtain a reference signal &; then multiply the digitized input voltage signal G with the aforementioned reference signal to obtain a current command Ve/, and then digitize the The error signal k after the input current signal 屯 is subtracted from the current command W is sent to a current control unit 222; the current 201025804 flow control unit tl 222 (Current Controller) adopts an average current (Average Current) control mode, which is the error obtained. The signal c is generated by the proportional-integral controller and the pulse width modulation module 3 to generate a pulse width modulation signal 砵; the average current control mode can force the input current waveform to follow the input voltage waveform, so that the power factor is as close as possible to the unit power The control of the second conversion circuit 12 by the digital signal processor 22 is a single loop control, which digitizes the second output voltage G and the second reference power.匕π subtraction 'the obtained error signal Ver2 is voltage-controlled by the voltage feedback control unit 223 and the pulse width modulation module 3' generates a pulse width modulation signal from 2. The voltage control unit 221, the current control unit 222 and the voltage feedback control unit 223 parameter values are shown in Table 1. Table 1 control category KP ki voltage control unit 0.5 0.0003 current control unit 1.0 0.5 voltage feedback control unit 0.01 0.05 In summary, The sampling method of the voltage conversion system of the present invention directly controls the input signal and output of the first-stage converter 11 and the second-stage converter 12 near the midpoint of the duty cycle of the previous pulse width modulation signal by the control module 2 The signal is sampled, and the sampling result is digitally processed to calculate the duty cycle of the next pulse width modulation signal during the period of the previous pulse width modulation signal, so that no additional interrupt signal is needed, thereby improving Voltage 201025804 · . Conversion reduction efficiency, also makes the program more concise in design. However, the above is only the present invention. It is to be understood that the scope of the invention is not to be construed as limiting the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit block diagram illustrating a conventional two-stage converter system; FIG. 2 is a system block diagram illustrating a preferred embodiment of the present invention; and FIG. 3 is a flowchart illustration Sampling method of voltage conversion system of the invention
9 201025804 【主要元件符號說明】 1…… •…電壓轉換模組 222 .··.· ••電流控制單元 11 ··.·· •…第一級轉換器 223 ·.·.· ••電壓回授控制單 12··..· •…第二級轉換器 元 2…… •…控制模組 23........ ••除法器 21••… •…類比/數位轉換器 24....... ••循環計數器 22••… •…數位訊號處理器 25....... ••比較電路 221 ··· •…電壓控制單元 步驟51 〜54 109 201025804 [Explanation of main component symbols] 1... •...Voltage conversion module 222 .····•• Current control unit 11 ······...First-stage converter 223 ·····••Voltage Feedback Control List 12··..·......Second Level Converter Element 2... •...Control Module 23........••Divider 21••... •... Analog/Digital Converter 24....... ••Cycle counter 22••... •...Digital signal processor 25.......••Compare circuit 221 ··· •...Voltage control unit Steps 51 to 54 10