1303691 九、發明說明： 【發明所屬^_技術領滅】 相關申請案之交互參照 本案請求美國專利申請案第11/218,757號，申請日2005 5年9月2曰，及第11/422,668號，申請曰2006年6月7日之優先 權。 發明領域 大致上本發明係有關可變速驅動器，更特別係有關用 於暖氣、通風、空調及冷凍(HVAC&R)設備之具有電壓驟降 10 安渡駕御能力之可變速驅動器。 L mT 1 發明背景 可變速驅動器（VSD)用於HVAC&R系統來提供可變振 幅和可變頻率交流電壓予驅動冷凍壓縮機的馬達。VSD典 15型係由一輸入整流器、一直流鏈路、及一反流器所組成。 由電力公司以固定振幅和固定頻率所供應的市電交流電 壓，藉VSD輸入整流器整流成為直流電壓。直流電壓係藉 於直流鏈路上具有能量儲存能力的被動元件（例如電容器） 來濾波及穩波。然後直流鏈路電壓被反流成為可變振幅可 20變頻率交流電壓，饋送至電力負載。於HVAC&R設備中， 電力負載通常係_接至壓縮機的電動馬達。Vsd對於發生 於電力公司的電源輸入的欠電壓情況(稱作為電壓驟降)特 別敏感。此種電壓驟降除非以其它方式經過校正或補償， 否則將反映至直流鏈路電壓和負載。大部分的市電電壓驟 5 1303691 降發生時間短，約為數毫秒至數秒。此等電壓驟降造成直 流鏈路電壓的驟降，以及VSD系統的關閉。VSD系統可安 渡駕御電壓驟降而不必關閉，以及於輸入電壓回復後VSD 回復操作的能力為較佳，原因在於如此可縮短HVAC&R設 5備的停機時間。對基於電壓源反流器（VSI)技術的VSD而 言’安渡駕御能力典型係經由將直流鏈路電壓維持於額定 值或接近額定值來達成。然後VSD可提供足夠電壓來驅動 電動馬達。否則，若直流鏈路充分下降至低於其額定值， 則V S D和急冷器控制系統將關閉以防馬達或壓縮機系統的 1〇不規則操作且可能有害的操作。 但最常見用於VSD的整流器類型為被動整流器。被動 整流器典型包括一三相二極體電橋。使用被動整流器，直 流鏈路電壓係與輸入市電電壓呈正比。因此被動整流器不 會補償輸入市電電壓的變化。結果電壓驟降將造成直流鏈 I5路電壓的下降，又造成VSD的關閉。 當被動整流器用於VSD時，改良安渡駕御能力的一種 了月b方式係提供連接至直流鏈路的額外電源，如Annette von Jouanne等人，可調速驅動器的安渡駕御替***法評 估，第35屆IEEE工業應用異動9〇8 (1999年)所述，該文以引 20用方式併入此處。此種額外電源可由額外電容器、直流升 壓變流器、電池、超電容器、馬達發電機組、飛輪、超傳 導磁能儲存系統、燃料電池等所提供。全部此等皆需要額 外的硬體，因此可顯著增高VSD的成本。一種相對廉價的 提高有被動前端之VSD之安渡駕御能力的方式，使用負載 6 1303691 慣性來於電壓驟降期間產生電力（也述於前文引述之 Annette von Jouanne等人）。為了達成此種提高安渡駕御能 力之方式，電壓驟降期間的反流器輸出頻率調整至略低於 馬達負載頻率值。如此造成馬達做為發電機，來將直流鏈 5 路電壓維持於期望的位準。此種方法典型要求馬達速度和 電流感測器，如此增加VSD的成本。 美國專利第6,686,718號說明多種提高VSD的安渡駕御 能力之技術。舉例言之，另一種可能的提高VSD的安渡駕 御能力之方式係使用主動整流器。此種整流器透過使用可 10 將市電電流切換開關的電力裝置，連同特殊控制方法，可 補償輸入市電電壓的變化。因此直流鏈路電壓可被維持於 夠大值來防止VSD的關閉。此種技術說明於Annabelle van Zyl等人’具有主動整流器之可調速馬達之電壓驟降安渡駕 御，第34屆IEEE工業應用之異動1270 (1998年），以引用方 15 式併入此處。 其中一種主動整流器係採用一脈寬調變(PWM)升壓整 流器。於輸入市電電壓的降低或驟降期間，直流鏈路電壓 可於名目值密切調節。但升壓整流器的輸入交流電流係隨 著市電電壓的下降而增高。由於升壓整流器元件的實際電 20流傳導或電流切換極限，輸入交流電流不允許無限制升 高。反而必須控制（經由升壓整流器控制演繹法則來控制）， 讓電流不超過預定極限，稱作為升壓整流器電流極限。主 要升壓整流器的輸入電流係低於電流極限或為電流極限， 則升壓整流器的輸出直流電壓可被密切控制於名目設定 7 1303691 點。但若於到達升壓整流器的電流極限後市電電壓仍然持 績下降，則升壓整流器無法再將輸出直流電壓調整為設定 值’但輸入電流仍然維持控制於電流極限位準。 隨著VSD的反流器區段持續從直流鏈路電容器汲取電 5 /危’來以於電壓驟降起點之前相同的電力位準來驅動馬 達’儲存於直流鏈路電容器中的能量轉成負載，直流鏈路 電壓下降。如果此種情況持續一段夠長時間，則直流鏈路 電壓將下降至低於預定的故障臨界值，急冷器系統最終關 閉。 1〇 因此’需要有一種提高應用於HVAC&R系統的VSD的 安渡駕御能力超越前述業界現況通用VSD的電流安渡駕御 月b力之方法。此種新穎方法係基於於電壓驟降期間升壓與 控制直流鏈路電壓來最大化VSD和HVAC&R系統的操作時 間週期’捕捉且維持儲存於旋轉中的馬達與壓縮機慣性中 15的最大忐置，俾便保有能量於直流鏈路電路，且利用儲存 於H VAC&R㈣的冷媒和相路㈣能量來最大化於輸入 電壓驟降期間系統的安渡駕御能力。 【考务明内容】 發明概要 本發明揭示一種於用於HVAC&R系統之一 VSD中提供 安渡駕御能力之方法’包含_馬達機械減—壓縮機，及 -可變速驅動器來供電予馬達。可變速驅動器包括一主動 整流為階段及藉直流鏈路階段所電减的反流器階段。市 電父机電壓、輪入交流電流、直流鏈路電壓及馬達交流電 8 1303691 流全部皆由該系統所監視及/或感測。於正常操作期間以及 於電壓驟降期間，直流鏈路階段的直流電壓係透過主動整 流器而被調節至一設定點。響應於輸入主動整流器階段的 輸入電流達到預定電流極限值，直流鏈路階段的直流電壓 5的調節進一步從主動整流器階段移轉至反流器階段，於冷 媒系統中由壓縮機所進行的工作停止。然後經由將電流從 馬達反向至直流鏈路，直流鏈路階段的直流電壓係透過反 流器控制。響應於被監視的市電交流電壓回復至預定臨界 值電壓值，直流鏈路階段的直流電壓控制返回給主動整流 10 器階段。 15 20 於本發明之一個態樣中，揭示_種控制一可變速驅動 器來安渡駕御-電壓驟降之方法。該方法包括下列階段： 提仏馬達及一壓縮機耦接至一機械負載；提供一可變速 驅動器來1、電予4馬達’該可變速驅動器包括藉一直流鍵 路階段所_接的-主動變流器階段及—反流器階段；監 視該直流鏈路階段之直流電壓；錢h動變流器階段之 輪入參數；響應於所監視的直流断電壓的改變，來以主 動變流器調節直流鏈路階段的錢t壓；響應於直流電壓 低=定第-臨界值電壓，將直_路階段的直流電壓的 „至反流器階段；由壓縮機去除機械負載；以及經 =馬達至直流鏈路階段的電流，以反流器階段來控 制直流鏈路階段的直流電壓。 於另 態樣中，本發明係關於一種 高電壓驟降安渡駕御能力之方法， 於一急冷器系統提 5亥方法包含下列步 驟 9 1303691 提供一機械柄聯之一馬達及一壓縮機；提供一可變速驅動 器來供電予該馬達，該可變速驅動器包括藉一直流鏈路階 段所電耦接的一主動變流器階段及一反流器階段；監視該 ‘ 直流鏈路階段之直流電壓；監視該主動變流器階段之輸入 • 5 參數；經由主動變流器階段來調節直流鏈路階段的直流電 壓；經由反流器階段來調節馬達速度；響應於直流鏈路階 段的直流電壓低於預定第一臨界值電壓，將直流鏈路階段 的直流電壓的調節移轉至反流器階段；卸載壓縮機；讓主 • 動變流器階段不能運作；以及經由反向由馬達至直流鏈路 10階段的電流，以反流器階段來控制直流鏈路階段的直流電 壓。 本發明亦係關於一種急冷器系統，包含一壓縮機、一 冷凝器、及一氣化器連接成為封閉的冷媒回路；一卸載裝 置用來響應於壓縮機運轉速度的降低而卸載壓縮機；連接 15於壓縮機的馬達來供電予壓縮機；及連接於該馬達之一可 變速驅動器，該可變速驅動器係組配來以固定輸入交流電 • 壓及固定輸入頻率接收輸入交流電力，以及提供於可變電 壓及可變頻率之輸出電力予馬達，該可變電壓具有最大電 壓的幅度係大於固定式輸入交流電壓，以及該可變頻率具 20有最大頻率係大於該固定式輸入頻率，該可變速驅動器包 含·連接至一父流電源來提供輸入交流電力之一變流器階 段，δ亥變流為階段經組配來將輸入交流電麼轉換成直流電 壓；連接至該變流H階段之-錢鏈路，該錢鏈路經組 配來濾波變流器階段的直流電壓且儲存能量；連接至該直 10 1303691 流鏈路之一反流器階段，該反流器階段係組配來對具有可 變電壓和可變頻率的馬達，將直流鏈路的直流電壓轉換成 馬達的輸出電力；控制該可變速驅動器之操作之一控制面 ’ 板，該控制面板係組配來響應於直流電壓係低於預定第一 • 5 臨界值電壓，以反流器階段來調節直流鏈路階段的直流電 壓；其中該控制面板係經由提供控制信號來以機械方式卸 載壓縮機，來以反流器階段調節直流鏈路階段的直流電 壓；以及反向電流由馬達至直流鏈路階段來控制直流鏈路 i 階段的直流電壓。 10 本發明之一項優點係提供改良之輸入電壓驟降安渡駕 御能力，以防止於輸入電壓驟降期間的急冷器系統關機。 本發明之另一項優點係最小化於電壓驟降期間直流鏈 路電容器的放電，經由急冷器系統的機械卸載來維持能量 儲存於馬達和壓縮機的旋轉部分，仰賴冷媒及被急冷的水 15 或食鹽水系統之除熱能力來最大化HVAC&R系統之熱安渡 "駕御能力。 B 本發明之又另一優點係可於馬達與壓縮機之旋轉部分 與直流鏈路間反向能量的流動來供給能量予直流鏈路的能 力。 20 其它本發明之特徵及優點由後文較佳實施例之詳細說 明，結合附圖舉例說明本發明之原理將更為彰顯。 圖式簡單說明 第1圖示意顯示本發明之概略系統組態。 第2圖示意顯示用於本發明之可變速驅動器之一個實 11 1303691 施例。 第3圖示意顯示可用於本發明之一種冷凍系統。 第4圖顯禾本發明之簡化方塊圖。 第5 A圖顯示本發明之一實施例之流程圖。 第5B圖顯示本發明之一較佳實施例之流程圖。 第6圖至第9圖顯示第5A圖所示流程圖之部分。 第10圖顯示第5B圖之流程圖之部分。 可能時’各圖間將使用相同的元件符號來表示相同或 類似的部分。 10 【實施冷式】 較佳實施例之詳細說明 第1圖大致上顯示本發明之系統組態。交流電源1〇2供 、’、6固疋式電壓和頻率的交流電力予可變速驅動器（VSD) 104,可變速驅動器（VSD) ι〇4又供給可變電壓和頻率交流 15電力與馬達106。馬達1〇6較佳係用來驅動冷凍系統或急冷 器系統的相對應的壓縮機(大致上參考第3圖）。交流電源1〇2 從存在於現場的交流電力格栅或分配系統，提供單相或多 相（例如三相）固定電壓且固定頻率交流電力予VSD 104。交 流電力格柵可由電力公司直接供應，或可由電力公司與交 20 流電力格柵間的一個或多個變壓小站供應。依據相對應的 交流電力格柵而定，交流電源102較佳係供給於市係供給於 市電頻率50 Hz或60 Hz之200 V、230 V、380 V、460 V、或 575 V之三相交流電壓或市電電壓予VSD 104。須了解依據 交流電力格柵的組配而定，交流電源102可提供任何適當的 12 1303691 固定市電電壓或固定市電頻率予VSD 104。此外，一個特定 位置可能有多個交流電力格柵，其可滿足不同的市電電壓 和市電頻率要求。舉例言之，一個位置可能有230 VAC電力 • 格柵來因應某些用途，而460 VAC電力格柵來因應其它用 • 5 途。 VSD 104從交流電源102接收具有特定固定市電電壓和 固定市電頻率的交流電力，且提供於期望的電壓和期望頻 率之交流電力予馬達106，電壓和頻率二者可改變來滿足特 Φ 定要求。較佳，VSD 104可提供交流電力予馬達1〇6，該交 10 流電力比較接收自交流電源102的固定電壓和固定頻率，具 有更高的電壓和頻率或更低的電壓和頻率。第2圖示意顯示 於VSD 104的一個實施例中的若干元件。VSD 104有三個階 段：整流器/變流器階段202、直流鏈路階段2〇4及反流器階 段206。整流器/變流器202將交流電源102的固定頻率、固 15定振幅AC電壓轉換成為DC電壓。直流鍵路2〇4濾、波變流器 202的直流電力’且設有能量儲存元件，諸如電容器及/或 ® 電感器。最後，反流器206將直流鏈路2〇4的直流電壓變換 成為馬達106使用的可變頻率、可變振幅AC電壓。 由於VSD 104可提供可變輸出電壓和可變頻率予馬達 20 106,依據馬達的特定負載而定，馬達可於多種不同條件操 作’例如於恆定通量模式或恆定伏特/赫茲模式操作。較 仏，控制面板、微處理斋或控制器可提供控制信號予 104,來控制VSD 104及馬達106的操作，依據控制面板所接 收的特定感測器讀取值而定，可對VSD 104和馬達106提供 13 1303691 最佳操作設定值。舉例言之，於第3圖之冷凍系統3〇〇中， 控制面板308可調整VSD 104的輸出電壓和頻率，來與冷凍 系統變化中的情況相對應，換言之，控制面板308響應於壓 縮機302的負載狀況的增減，提高或降低VSD 104的輸出電 5壓和頻率，俾便獲得馬達丨〇6的期望的操作速度和壓縮機 302期望的輸出負載。 於較佳實施例中，整流器/變流器2〇2為具有絕緣閘兩 極電晶體(IGBT)的三相脈寬調變升壓整流器，來提供升壓 直流電壓予直流鏈路2〇4，來獲得VSD 104的最大RMS輸出 10電壓高於VSD 104的輸入電壓。於另一個實施例中，變流器 202可為二極體或閘流體整流器，變流器2〇2可耦接於升壓 DC/DC變流器，來提供升壓直流電壓予直流鏈路2〇4，俾獲 传VSD 104的輸出電壓係大於VSD 104的輸入電壓。於另一 個實施例中，整流器/變流器202可為不具有升壓能力的被 15動二極體整流器或被動閘流體整流器。 於本發明之較佳實施例中，VSD 1〇4提供輸出電壓和輸 出頻率，其分別為提供予VSD 104的固定電壓和固定頻率之 至少1.04倍和3倍。此外，須了解VSD 104可集合第2圖所示 之不同組件，只要VSD 104可對馬達106提供適當輸出電壓 2〇 和輸出頻率即可。1303691 IX. Description of invention: [Inventions belong to ^_Technical collar] The cross-references of the relevant applications refer to US Patent Application No. 11/218,757, the filing date of September 5, 2005, and 11/422,668. Application for priority on June 7, 2006. FIELD OF THE INVENTION The present invention relates generally to variable speed drives, and more particularly to variable speed drives having a voltage dip 10 for use in heating, ventilation, air conditioning, and refrigeration (HVAC & R) equipment. L mT 1 BACKGROUND OF THE INVENTION Variable speed drives (VSD) are used in HVAC & R systems to provide variable amplitude and variable frequency AC voltage to a motor that drives a refrigeration compressor. The VSD Model 15 consists of an input rectifier, a DC link, and a inverter. The mains AC voltage supplied by the power company at a fixed amplitude and a fixed frequency is rectified by the VSD input rectifier to become a DC voltage. The DC voltage is filtered and stabilized by passive components (such as capacitors) with energy storage capability on the DC link. The DC link voltage is then reversed into a variable amplitude, variable frequency AC voltage that is fed to the electrical load. In HVAC & R equipment, the electrical load is usually connected to the electric motor of the compressor. Vsd is particularly sensitive to undervoltage conditions (called voltage dips) that occur at the power company's power input. This voltage dip will be reflected to the DC link voltage and load unless otherwise corrected or compensated. Most of the mains voltage steps 5 1303691 occur for a short period of time, from a few milliseconds to a few seconds. These voltage dips cause a dip in the DC link voltage and the VSD system is shut down. The VSD system can safely withstand voltage dips without having to shut down, and the ability of the VSD to resume operation after the input voltage is restored is preferred because it reduces the downtime of HVAC&R equipment. For VSD based on voltage source inverter (VSI) technology, the typical robustness is achieved by maintaining the DC link voltage at or near the rated value. The VSD then provides enough voltage to drive the electric motor. Otherwise, if the DC link drops sufficiently below its rating, the V S D and the chiller control system will shut down to prevent an irregular operation of the motor or compressor system and potentially harmful operation. But the most common type of rectifier used for VSD is the passive rectifier. Passive rectifiers typically include a three-phase diode bridge. With a passive rectifier, the DC link voltage is proportional to the input mains voltage. Therefore, the passive rectifier does not compensate for changes in the input mains voltage. As a result, the voltage dip will cause the voltage of the DC link I5 to drop, which in turn causes the VSD to turn off. When a passive rectifier is used in a VSD, a monthly b-mode that improves the ride comfort capability provides additional power to the DC link, such as Annette von Jouanne et al., Evaluation of the Amway Control Alternatives for Adjustable Drives, 35th IEEE Industrial Application Transaction 9〇8 (1999), which is incorporated herein by reference. This additional power supply can be provided by additional capacitors, DC boost converters, batteries, ultracapacitors, motor generator sets, flywheels, superconducting magnetic energy storage systems, fuel cells, and the like. All of these require additional hardware, which can significantly increase the cost of VSD. A relatively inexpensive way to improve the safety of a VSD with a passive front end, using load 6 1303691 inertia to generate electricity during a voltage dip (also described in Annette von Jouanne et al., cited above). In order to achieve this way of improving the ability to control the ride, the inverter output frequency during the voltage dip is adjusted to be slightly lower than the motor load frequency. This causes the motor to act as a generator to maintain the DC link 5 voltages at the desired level. This approach typically requires motor speed and current sensors, which increases the cost of the VSD. U.S. Patent No. 6,686,718 describes various techniques for improving the ability to control VSD. For example, another possible way to improve the safety of VSD is to use an active rectifier. This type of rectifier compensates for changes in the input mains voltage by using a power unit that can switch the mains current switch, together with a special control method. Therefore, the DC link voltage can be maintained at a large enough value to prevent the VSD from being turned off. This technique is described in Annabelle van Zyl et al.'s voltage sags of an adjustable speed motor with active rectifiers. The 34th IEEE Industrial Application Transaction 1270 (1998) is incorporated herein by reference. One of the active rectifiers uses a pulse width modulation (PWM) boost rectifier. During the decrease or dip of the input mains voltage, the DC link voltage can be closely adjusted to the nominal value. However, the input AC current of the boost rectifier increases as the mains voltage decreases. The input AC current does not allow for an unrestricted rise due to the actual current flow or current switching limit of the boost rectifier component. Instead, it must be controlled (controlled by the boost rectifier control deductive law) so that the current does not exceed the predetermined limit, referred to as the boost rectifier current limit. If the input current of the main boost rectifier is below the current limit or is the current limit, the output DC voltage of the boost rectifier can be closely controlled to the nominal setting of 7 1303691. However, if the mains voltage still falls after reaching the current limit of the boost rectifier, the boost rectifier can no longer adjust the output DC voltage to the set value' but the input current remains controlled to the current limit level. As the VSD's inverter section continues to draw power from the DC link capacitors to drive the motor's energy stored in the DC link capacitor to the same power level before the voltage dip start point The DC link voltage drops. If this condition persists for a long time, the DC link voltage will drop below the predetermined fault threshold and the chiller system will eventually shut down. 1〇 Therefore, there is a need for a method to improve the VSD of the VSD applied to the HVAC & R system and to exceed the current state of the art VSD. This novel approach is based on boosting and controlling the DC link voltage during voltage dips to maximize the operating time period of the VSD and HVAC & R system 'capture and maintain the maximum 15 of the motor and compressor inertia stored in rotation. The device maintains energy in the DC link circuit and utilizes the refrigerant and phase (4) energy stored in HVAC & R (4) to maximize the system's ability to withstand the dip during input voltage dips. [Certificate of the Invention] Summary of the Invention The present invention discloses a method for providing an Axis control capability in a VSD for use in a HVAC & R system, including a motor mechanical reduction compressor, and a variable speed drive for supplying power to the motor. The variable speed drive includes a phase of the inverter that is actively rectified for the phase and by the DC link phase. The city's parent voltage, wheeled AC current, DC link voltage, and motor AC 8 1303691 flow are all monitored and/or sensed by the system. During normal operation and during a voltage dip, the DC voltage during the DC link phase is regulated to a set point by the active rectifier. In response to the input current of the input active rectifier stage reaching a predetermined current limit value, the regulation of the DC voltage 5 of the DC link phase is further shifted from the active rectifier stage to the inverter stage, where the operation of the compressor is stopped in the refrigerant system . The DC voltage in the DC link phase is then controlled by the inverter by reversing the current from the motor to the DC link. In response to the monitored mains AC voltage returning to a predetermined threshold voltage value, the DC voltage control of the DC link phase is returned to the active rectification stage. 15 20 In one aspect of the invention, a method of controlling a variable speed drive to ride a voltage-to-voltage dip is disclosed. The method comprises the following steps: the lifting motor and a compressor are coupled to a mechanical load; providing a variable speed drive to the electric motor; the variable speed drive comprising the active-current phase a converter stage and a -inverter stage; monitoring a DC voltage of the DC link phase; a wheeling parameter of the phase of the power converter; and an active converter in response to a change in the monitored DC voltage Adjusting the voltage t voltage in the DC link phase; in response to the DC voltage being low = the first threshold voltage, the direct voltage of the straight phase is „to the inverter phase; the mechanical load is removed by the compressor; and the = motor is The current in the DC link phase controls the DC voltage of the DC link phase in the inverter phase. In another aspect, the present invention relates to a method for high voltage sudden dropover control capability, in a chiller system. The method includes the following steps: 9 1303691 provides a motor with a mechanical handle and a compressor; and provides a variable speed drive for supplying power to the motor, the variable speed drive including a DC link An active converter stage and a inverter stage electrically coupled to the segment; monitoring the DC voltage of the 'DC link phase; monitoring the input of the active converter stage • 5 parameters; via the active converter stage Adjusting the DC voltage of the DC link phase; adjusting the motor speed via the inverter phase; and adjusting the DC voltage of the DC link phase to the reverse in response to the DC voltage of the DC link phase being lower than the predetermined first threshold voltage The stage of the flow; unloading the compressor; leaving the main converter stage inoperable; and controlling the DC voltage of the DC link stage in the inverter stage by reversing the current from the motor to the DC link 10 stages. The invention also relates to a chiller system comprising a compressor, a condenser, and a gasifier connected to form a closed refrigerant circuit; an unloading device for unloading the compressor in response to a decrease in the operating speed of the compressor; a motor of the compressor to supply power to the compressor; and a variable speed drive coupled to the motor, the variable speed drive being coupled to a fixed input AC power and pressure and fixed input frequency receive input AC power, and provide output power to variable voltage and variable frequency to the motor, the variable voltage having a maximum voltage amplitude greater than a fixed input AC voltage, and the variable frequency The 20 has a maximum frequency greater than the fixed input frequency, and the variable speed drive includes a converter current connected to a parent current source to provide input AC power, and the delta current is phased to form an input AC Converted to a DC voltage; connected to the money-link of the H-phase of the converter, the money link is configured to filter the DC voltage of the converter stage and store energy; connected to one of the Straight 10 1303691 flow links In the inverter stage, the inverter stage is configured to convert a DC voltage of the DC link into a motor output power for a motor having a variable voltage and a variable frequency; controlling one of the operations of the variable speed drive a 'plate, the control panel is configured to adjust the DC link stage in a inverter phase in response to the DC voltage being lower than a predetermined first threshold voltage a DC voltage of the segment; wherein the control panel mechanically unloads the compressor by providing a control signal to regulate the DC voltage of the DC link phase in a inverter phase; and the reverse current is controlled by a motor to DC link phase DC voltage in the i-phase of the DC link. An advantage of the present invention is to provide improved input voltage dip safety to prevent shutdown of the chiller system during input voltage dips. Another advantage of the present invention is to minimize the discharge of the DC link capacitor during voltage dips, maintaining the energy stored in the rotating portion of the motor and compressor via mechanical unloading of the chiller system, relying on the refrigerant and the quenched water 15 Or the heat removal capacity of the brine system to maximize the heat and safety of the HVAC & R system. Another advantage of the present invention is the ability to supply energy to the DC link by the flow of reverse energy between the rotating portion of the motor and the compressor and the DC link. The features and advantages of the present invention will be more apparent from the detailed description of the preferred embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic representation of a schematic system configuration of the present invention. Figure 2 is a schematic illustration of a real 11 1303691 embodiment for a variable speed drive of the present invention. Figure 3 is a schematic representation of a refrigeration system useful in the present invention. Figure 4 shows a simplified block diagram of the present invention. Figure 5A shows a flow chart of an embodiment of the present invention. Figure 5B is a flow chart showing a preferred embodiment of the present invention. Figures 6 through 9 show portions of the flow chart shown in Figure 5A. Figure 10 shows a portion of the flow chart of Figure 5B. Wherever possible, the same reference numerals will be used to refer to the same or similar parts. 10 [Implementation of Cold Mode] Detailed Description of Preferred Embodiments Fig. 1 roughly shows the system configuration of the present invention. AC power supply 1〇2, ', 6 solid voltage and frequency AC power to variable speed drive (VSD) 104, variable speed drive (VSD) ι〇4 supply variable voltage and frequency AC 15 power and motor 106 . The motor 1〇6 is preferably used to drive a corresponding compressor of the refrigeration system or the chiller system (generally reference to Fig. 3). The AC power source 1〇2 provides a single-phase or multi-phase (eg, three-phase) fixed voltage and fixed-frequency AC power to the VSD 104 from an AC power grid or distribution system present in the field. The AC power grid may be supplied directly by the power company or may be supplied by one or more transformer stations between the power company and the AC power grid. Depending on the corresponding AC power grid, the AC power source 102 is preferably supplied to a three-phase AC supplied by the municipality at 200 V, 230 V, 380 V, 460 V, or 575 V at a mains frequency of 50 Hz or 60 Hz. Voltage or mains voltage to VSD 104. It is to be understood that the AC power source 102 can provide any suitable 12 1303691 fixed mains voltage or fixed mains frequency to the VSD 104 depending on the combination of the AC power grid. In addition, there may be multiple AC power grids in a particular location that can accommodate different mains voltages and mains frequency requirements. For example, a location may have 230 VAC power • A grille for some uses, and a 460 VAC power grid for other uses • 5 ways. The VSD 104 receives AC power having a particular fixed mains voltage and a fixed mains frequency from the AC power source 102, and provides AC power at a desired voltage and a desired frequency to the motor 106, both of which can be varied to meet the specified requirements. Preferably, the VSD 104 provides AC power to the motor 1〇6 which compares the fixed voltage and the fixed frequency received from the AC power source 102 with a higher voltage and frequency or lower voltage and frequency. FIG. 2 is a schematic illustration of several components in one embodiment of VSD 104. The VSD 104 has three phases: a rectifier/converter phase 202, a DC link phase 2〇4, and a inverter phase 206. The rectifier/converter 202 converts the fixed frequency of the AC power source 102 and the fixed amplitude AC voltage into a DC voltage. The DC link 2〇4 filters, the DC power of the wave converter 202' and is provided with energy storage elements such as capacitors and/or ® inductors. Finally, the inverter 206 converts the DC voltage of the DC link 2〇4 into a variable frequency, variable amplitude AC voltage used by the motor 106. Since the VSD 104 can provide a variable output voltage and variable frequency to the motor 20 106, depending on the particular load of the motor, the motor can operate in a variety of different conditions, such as in constant flux mode or constant volts/hertz mode. More generally, the control panel, microprocessor, or controller can provide control signals to 104 to control the operation of VSD 104 and motor 106, depending on the particular sensor read value received by the control panel, and can be applied to VSD 104 and Motor 106 provides 13 1303691 optimal operating settings. For example, in the refrigeration system 3 of FIG. 3, the control panel 308 can adjust the output voltage and frequency of the VSD 104 to correspond to the situation in the refrigeration system change, in other words, the control panel 308 is responsive to the compressor 302. The increase or decrease of the load condition increases or decreases the output voltage 5 and frequency of the VSD 104 to obtain the desired operating speed of the motor 丨〇6 and the desired output load of the compressor 302. In a preferred embodiment, the rectifier/converter 2〇2 is a three-phase pulse width modulation boost rectifier having an insulated gate bipolar transistor (IGBT) to provide a boosted DC voltage to the DC link 2〇4, The maximum RMS output 10 voltage of the VSD 104 is obtained to be higher than the input voltage of the VSD 104. In another embodiment, the current transformer 202 can be a diode or a thyristor rectifier, and the converter 2 〇 2 can be coupled to a step-up DC/DC converter to provide a boosted DC voltage to the DC link. 2〇4, the output voltage of the captured VSD 104 is greater than the input voltage of the VSD 104. In another embodiment, the rectifier/converter 202 can be a 15th diode rectifier or a passive thyristor rectifier that does not have boost capability. In a preferred embodiment of the invention, VSD 1 〇 4 provides an output voltage and an output frequency which are at least 1.04 and 3 times the fixed voltage and the fixed frequency supplied to VSD 104, respectively. In addition, it is to be understood that the VSD 104 can assemble the different components shown in Figure 2 as long as the VSD 104 can provide the motor 106 with an appropriate output voltage 2 〇 and output frequency.
VSD 104也包括一預充電系統（圖中未顯示），預充電系 統可控制直流鏈路電壓由〇伏特升高至接近於交流市電電 壓峰值的電壓值，以避免當AC電壓初次施加於VSD 1〇4時 於VSD 104的大型湧入電流，該湧入電流可能損害VSD 14 1303691 的組成元件。預充電系統包括預充電接觸器，用來將預充 電電阻器連接於輸入交流電源102與整流器/變流器2〇2 間，或偶爾連接於整流器/變流器202的輸出與直流鏈路2〇4 間。此等預充電電阻器將湧入電流限於可管理的程度。於 5預充電完成後，藉開啟預充電接觸器，將預充電電阻器從 電路中排除，交流電源1〇2係經由關閉另一個接觸器（稱作 為電源供應接觸器）來直接連接至變流器202。於系統操作 期間’供應接觸器維持為通路。另外，經由使用適當電源 半導體裝置’麵接適當預充電控制裝置，預充電裝置可結 10 合入整流器/變流器202的設計中。 此外，VSD 104可對HVAC&R系統提供具有約一個單 位電力因數的電力。最後，VSD 104可調整馬達1〇6所接收 的電壓和頻率成為高於或低於VSD 104所接收的固定市電 電壓和固定市電頻率，允許HVAC&R系統於多種國外和國 15内的電力格柵操作，而無需對不同的電源更動馬達106或 VSD 104 ° 馬達106較佳為可以可變速驅動的感應馬達。感應馬達 可具有任一種適當的極配置，包括二極、四極或六極。感 應馬達係用來驅動負載，較佳為如第3圖所示冷凍系統中的 20 壓縮機。 如第3圖所示’ HVAC、冷凍或液體急冷器系統300包括 一壓縮機302、一冷凝器304、一氣化器306及一控制面板 308。控制面板308可包括多個不同元件諸如類比至數位 (A/D)轉換器、微處理器、非依電性記憶體、及介面板，來 15 1303691 控制冷;東系統300的操作。控制面板3〇8也可用來控制vsd 104和馬達106的操作。習知冷束系統綱包括多項其它未顯 示於第3圖的特徵。此等特徵經過蓄意刪除俾便簡化附圖方 便說明。 5 襲機搬壓縮冷媒蒸氣，通過排放管絲輸送蒸氣至 冷凝器304。壓縮機302較佳為離心壓縮機，但也可為任一 種適當型別的壓縮機，例如螺桿壓縮機、往復式壓縮機等。 由壓縮機302輸送至冷凝器3〇4的冷媒蒸氣，進入於諸如空 氣或水等流體的熱交換關係、，經由與&體的熱交換關係的 10結果，與冷媒液體進行相改變。來自於冷凝器304，冷凝的 液體冷媒通過膨脹裝置（圖中未顯示）而流至氣化器306。 壓縮機302可包括-負載改變裝置3〇3，來改變壓縮機 302的機械負載。於離心壓縮機中，負載改變裝置3〇3可為 預轉輪葉。來自於氣化器3〇6之壓縮機3〇2的進氣口或抽取 I5管線301，有一個或多個預轉輪葉或進氣口導件輪葉3〇3來 控制冷媒的流至壓縮機3〇2。作動器用來開啟負載改變裝置 303,俾增加冷媒至302的數量，藉此提高系統3〇〇的冷卻能 力。同理，作動器用來關閉負載改變裴置3〇3，俾減少冷媒 至302的數量，藉此降低系統3〇〇的冷卻能力。於螺桿壓縮 20機中，負載改變裝置3的可為滑閥。壓縮機的排放管線3〇7 了連接有止回閥305來防止冷媒的逆流，容後詳述。於另一 種組悲中，止回閥305可於抽取管線3〇1連接至壓縮機如2。 氣化器306包括冷卻負載之一供應管線和一回送管線 之連接。二次液體例如水、乙烯、氯化鈣食鹽水或氯化鈉 16 1303691 食鹽水透伽送管線前進進入氣化器306,以及透過供應管 線而伙孔,306运出。氣化器3〇6中的液體冷媒於二次液 體進入熱交換關係來降低二次液體的溫度。於氣化器观的 冷媒液體^於二次液體的熱交換關係結果，進行相變化 5艾成:媒二氣。於氣化器3〇6的蒸氣冷媒從氣化器3〇6送 出藉抽取&線回送至壓縮機3〇2來完成循環週期。須了解 々心304和氣化器3〇6的任一種適當組態皆可用於系統 3〇0仁先决條件為可獲得冷凝器遍和氣化器遍中的冷媒 的適當相變化。 10 —HVAC、冷;東或;夜體急冷“統綱可包括其它未顯示 於第3圖的結構。此等結構已經蓄意刪除來簡化附圖方便說 月此外’雖然第3圖顯示HVAC、冷;東或液體急冷器系統 300有-部壓縮機連接於單—冷媒鏈路，但須了解系統細 也可有多部壓縮機由單一VSD供電，連接於一或多個冷媒 15 回路中之各個回路。 控制面板308結合一壓縮機控制單元4〇6(參考第4圖）， 其决疋且貫作壓縮機的機械負載裝置303的位置，例如離心 壓縮機的預轉輪葉、或螺桿壓縮機的滑閥。響應於急冷器 系統的控制面板308所產生的冷卻命令信號，控制面板3〇8 20也控制壓縮機302及馬達106的速度。控制面板308將馬達速 度命令送至反流器控制單元4〇4(參考第4圖），反流器控制單 元404控制反流器206，來輸出電壓和頻率與馬達1〇6來產生 期望的壓縮機速度。反流器控制單元404較佳係使用向量控 制演繹法則，經由分開獨立控制馬達電流的通量產生分量 17 1303691 和轉矩產生分量，透過直接轉矩控制來控制馬達1〇6的速 度。 於後文控制說明中，直流鏈路電壓VDC、直流鏈路電壓 第一設定點vSTPT1、直流鏈路電壓第一臨界值、直流鍵 5 路電壓弟一設定點Vstpt2、及直流鍵路電壓截流臨界值 VUNDER為DC值’此處VSTPT1>VTH1>VSTPT2；>VUNDER;感測得 的輸入父流市電電壓VINAC及輸入交流電麼臨界值v扭⑼為 RMS值。本發明之較佳方法通常包含二步驟式操作模式來 提供於電壓驟降期間於VSD 104的輪入端的安渡駕御。於第 ίο 一步驟中，隨著交流市電電壓振幅的下降，2〇2(本實例為 升壓整流器）將直流鏈路電壓調節至其額定值，彷彿係於2 常的滿電壓操作般。經由提高輸入升壓整流器的輸入交流 電流，維持直流鏈路電壓於其設定點(Vstpti)補償輸入交^ 電[驟降。升壓整流為經由提高輸入電流至到達預定電流 15極限，來補償電壓的驟降。當升壓整流器到達預定電流極 限時，若市電電壓尚未回復至可接受的位準，則開始該方 f之第二步驟’為二實質同時的響應’第—響應係卸載壓 縮機，第二響應係從馬達和壓縮機的旋轉部分 供應電奸錢鏈路。 " 2〇 #考第4圖，壓縮機控制單以_動壓縮機地的 卸载裝置303,來最小化由直流鏈路電容器的冷康負载所耗 用的電力及馬達轉子和壓縮機旋轉部分的慣性。雖然機械 負、載可藉壓縮機控制單元4G6料，俾便保留儲存於旋㈣ $的能量，但反流器控制單㈣4從馬達速度控制模式切換 18 1303691 成直流鏈路電魔控制模式，經由控制馬達速度，來控制直 心鏈路電c振巾田至vSTPT2的位準。於電禮驟降期間，接收來 自控制面板、微處理器、或控制器308的命令，俾便依據控 制面板规所接收的特定感測器讀取值而定，對VSD 104和 5馬達则提供最佳操作設定值，該命令被彻1〇4所忽略。 如此強迫馬達106和卿機地做為發電機，造成儲存於盆 慣性中的需要量的能量被傳送至直流鏈路電容器。馬達ι〇6 的轉速於安«御期間下降，同時直流鏈路電壓維持於 VSTPT2。若儲存於旋轉部分的能量於市電輸入電壓回復正常 1〇範圍之前持續被耗用，則直流鏈路電壓將下降至低於預定 的界值，標示為vUNDER，系統將關機。 於有夕個反流器和壓縮機馬達連接到同一個直流鏈路 之系統中，反流器控制單元係以前文對單一反流器所述的 相同方式運作。主要差異在於事實上，各個反流器有其本 15身的臨界值VTH1 (例如vTHla、vTHib、v耻，此處a、b、c 表示不同的反流器）及其本身的設定點VSPT2 (例如VSPT2a、 Vspi^b、Vsp^c)。此種於不同反流器和壓縮機馬達間的臨界 值和設定點的分開，為多個反流器試圖來同時控制直流鏈 路電壓時防止可能的不穩定所需。 20 VSD包括主動整流器202,其可為脈寬調變升壓整流器 或其它升壓整流器類型。直流鏈路階段2〇4提供於節點4〇〇 的控制信號VDC，發射至整流器控制單元4〇2和反流器控制 單元404。控制單元402及404除了直流鏈路電壓之外也接收 其它控制信號，但於本圖中刪除以方便說明。控制單元4〇2 19 1303691 及404典型係位在VSD隔間内部，但也可位在於控制面板 308内部，或可分開安裝於不同的設備。 本發明之安渡駕御方法之一個實施例顯示於第5A圖。 流粒圖500大致上說明本發明之方法之一個態樣，始於步驟 5 502表示系統啟動。於系統啟動後，係以正常操作來運轉， 如步驟504所示，先決條件為來自於交流電源的市電電壓係 接近於名目市電電壓，換言之沒有電壓驟降，或市電電壓 開始驟降之低於名目市電電壓，但輸入升壓整流器的電流 係低於電流極限值，且直流鏈路電壓係維持於設定點 10 VSTPT1。於步驟504a，升壓整流器調整直流鏈路電壓；於步 驟504b，反流器持續如常操作來調整壓縮機速度；以及於 步驟504c，由控制硬體和軟體進行直流鏈路電壓的監視(參 考第6圖）。步驟5〇4a-504c可同時進行或循序進行，如步驟 504所示。第6圖所示順序僅供舉例說明之用。於步驟邓々， 15升Μ整流器之輸入電流係等於或低於升壓整流器的讀§電 流極限值。 於步驟506，VDC與預定臨界值Vthi比較。vthi之幅度 係低於直流鏈路電壓VsTPT1之名目設定點。舉例言之，若名 目直流鍵路電壓為Vstpi = 95〇 V，則vTH1可選擇為9〇〇伏 2〇特。若Vdc係低於VTHi，如此指示升壓整流器已經到達其電 流極限，而不再能調整直流鏈路電壓至其設定值，此後系 統前進至步驟508 (第7圖及第8圖）來卸載壓縮機3〇2，讓升 壓整流裔202和預充電裝置不能運作，以及變遷反流器2〇6 成為控制直流鏈路電壓。否則，系統返回步驟5〇4。直流鏈 20 1303691 路電壓vDC的監視可連續進行或循序進行，— 觸發系統回應，則於此處以分開步驟指示。De值的改變 如第7圖所示，步驟驗長係以步驟The VSD 104 also includes a pre-charging system (not shown) that controls the DC link voltage to rise from 〇 volts to a voltage value close to the AC mains voltage peak to avoid initial application of the AC voltage to the VSD 1 At 4 o'clock, a large inrush current to the VSD 104, which may damage the components of the VSD 14 1303691. The pre-charging system includes a pre-charging contactor for connecting the pre-charging resistor between the input AC power source 102 and the rectifier/converter 2〇2, or occasionally to the output of the rectifier/converter 202 and the DC link 2 〇4 rooms. These pre-charge resistors limit the inrush current to a manageable extent. After the pre-charging is completed, the pre-charging resistor is removed from the circuit by turning on the pre-charging contactor, and the AC power source 1〇2 is directly connected to the current transformer by closing the other contactor (referred to as a power supply contactor). 202. The supply contactor remains in the path during system operation. In addition, the precharge device can be incorporated into the design of the rectifier/converter 202 via the use of a suitable power semiconductor device' to interface with an appropriate precharge control device. In addition, the VSD 104 can provide power to the HVAC & R system having approximately one unit of power factor. Finally, the VSD 104 can adjust the voltage and frequency received by the motor 1〇6 to be higher or lower than the fixed mains voltage and the fixed mains frequency received by the VSD 104, allowing the HVAC&R system to be powered by a variety of foreign and national 15 The grid operates without the need to switch the motor 106 or VSD to a different power source. The motor 106 is preferably an induction motor that can be driven at a variable speed. The induction motor can have any suitable pole configuration, including two, four or six poles. The induction motor is used to drive the load, preferably a 20 compressor in the refrigeration system as shown in Figure 3. As shown in Fig. 3, the HVAC, refrigeration or liquid chiller system 300 includes a compressor 302, a condenser 304, a gasifier 306, and a control panel 308. Control panel 308 may include a number of different components such as analog to digital (A/D) converters, microprocessors, non-electrical memory, and interface panels to control the operation of the cold system; Control panel 3〇8 can also be used to control the operation of vsd 104 and motor 106. The conventional cold beam system includes a number of other features not shown in Fig. 3. These features have been deliberately deleted to simplify the drawing. 5 The machine moves the compressed refrigerant vapor and delivers the vapor to the condenser 304 through the discharge pipe. The compressor 302 is preferably a centrifugal compressor, but may be any suitable type of compressor such as a screw compressor, a reciprocating compressor or the like. The refrigerant vapor sent from the compressor 302 to the condenser 3〇4 enters a heat exchange relationship with a fluid such as air or water, and changes phase with the refrigerant liquid via a result of heat exchange with the & body. From the condenser 304, the condensed liquid refrigerant flows to the gasifier 306 through an expansion device (not shown). The compressor 302 can include a load change device 3〇3 to vary the mechanical load of the compressor 302. In the centrifugal compressor, the load changing device 3〇3 may be a pre-rotating vane. The intake port of the compressor 3〇2 from the gasifier 3〇6 or the extraction I5 line 301 has one or more pre-rotation vanes or inlet guide vanes 3〇3 to control the flow of the refrigerant to Compressor 3〇2. The actuator is used to activate the load changing device 303 to increase the amount of refrigerant to 302, thereby increasing the cooling capacity of the system. Similarly, the actuator is used to close the load change device 3〇3, reducing the amount of refrigerant to 302, thereby reducing the cooling capacity of the system. In the screw compression machine 20, the load changing device 3 may be a spool valve. A check valve 305 is connected to the discharge line 3〇7 of the compressor to prevent backflow of the refrigerant, which will be described in detail later. In another group of sorrows, the check valve 305 can be connected to the compressor such as 2 at the extraction line 3〇1. The gasifier 306 includes a connection of a supply line of a cooling load and a return line. A secondary liquid such as water, ethylene, calcium chloride brine or sodium chloride 16 1303691 brine is passed through the gasifier 306 and through the supply line and 306 is shipped. The liquid refrigerant in the gasifier 3〇6 enters a heat exchange relationship with the secondary liquid to lower the temperature of the secondary liquid. As a result of the heat exchange relationship between the refrigerant liquid and the secondary liquid in the gasifier, the phase change is carried out. 5 Ai Cheng: Medium two gas. The vapor refrigerant in the gasifier 3〇6 is sent from the gasifier 3〇6 to the extraction & line back to the compressor 3〇2 to complete the cycle. It is to be understood that any suitable configuration of the core 304 and the gasifier 3〇6 can be used in the system. The prerequisite is to obtain a suitable phase change of the condenser throughout the refrigerant in the gasifier. 10—HVAC, cold; East or; night body quenching “The system can include other structures not shown in Figure 3. These structures have been deliberately deleted to simplify the drawing and are convenient for the month.” Although Figure 3 shows HVAC, cold. East or liquid chiller system 300 has a - compressor connected to the single-refrigerant link, but it must be understood that the system can also have multiple compressors powered by a single VSD, connected to each of the one or more refrigerant 15 circuits The control panel 308 incorporates a compressor control unit 4〇6 (refer to FIG. 4) which is determined and co-ordinates the position of the mechanical load device 303 of the compressor, such as the pre-rotation vane of the centrifugal compressor, or screw compression. The slide valve of the machine. In response to the cooling command signal generated by the control panel 308 of the chiller system, the control panel 3 〇 8 20 also controls the speed of the compressor 302 and the motor 106. The control panel 308 sends the motor speed command to the inverter. Control unit 4〇4 (refer to Fig. 4), inverter control unit 404 controls inverter 206 to output voltage and frequency to motor 1〇6 to produce a desired compressor speed. Preferably, inverter control unit 404. Use vector control The law of 绎, by separately controlling the flux of the motor current to generate the component 17 1303691 and the torque generating component, and controlling the speed of the motor 1〇6 through the direct torque control. In the following description, the DC link voltage VDC, DC The first set point of the link voltage vSTPT1, the first critical value of the DC link voltage, the DC key 5 way voltage set point Vstpt2, and the DC link voltage cutoff threshold VUNDER is the DC value 'here VSTPT1> VTH1> VSTPT2; >VUNDER; sensed input parent current mains voltage VINAC and input AC power threshold value v twist (9) is the RMS value. The preferred method of the present invention typically includes a two-step mode of operation to provide during voltage dips during VSD 104 In the first step, as the AC mains voltage amplitude drops, 2〇2 (this example is a boost rectifier) adjusts the DC link voltage to its rated value, as if it were 2 Constant full-voltage operation. By increasing the input AC current of the input boost rectifier, the DC link voltage is maintained at its set point (Vstpti) to compensate for the input and output [Sink. Boost Rectification To compensate for the sudden drop in voltage by increasing the input current to the limit of reaching the predetermined current 15. When the boost rectifier reaches the predetermined current limit, if the mains voltage has not returned to an acceptable level, the second step of the f is started. 'The second simultaneous response' is the first response system to unload the compressor, and the second response is to supply the electric charge link from the rotating part of the motor and compressor. "2〇#考图4, compressor control list The unloading device 303 of the compressor ground is used to minimize the power consumed by the cold bus load of the DC link capacitor and the inertia of the motor rotor and the rotating portion of the compressor. Although the mechanical negative load can be stored by the compressor control unit 4G6, the energy stored in the rotary (four) $ is retained, but the inverter control single (four) 4 is switched from the motor speed control mode 18 1303691 into the DC link electric magic control mode, via Control the motor speed to control the level of the straight-line link electric c-snake to vSTPT2. During the dip of the electronic ballot, commands from the control panel, microprocessor, or controller 308 are received, depending on the particular sensor read value received by the control panel gauge, and are provided for the VSD 104 and 5 motors. The optimal operation setting value is ignored by the command. This forces the motor 106 and the controller to act as a generator, causing the required amount of energy stored in the inertia of the basin to be transferred to the DC link capacitor. The speed of the motor ι〇6 drops during the period of the ampere, while the DC link voltage is maintained at VSTPT2. If the energy stored in the rotating part is continuously consumed before the mains input voltage returns to the normal range of 1〇, the DC link voltage will drop below the predetermined threshold, marked as vUNDER, and the system will shut down. In a system in which a coupler and a compressor motor are connected to the same DC link, the inverter control unit operates in the same manner as previously described for a single inverter. The main difference is that in fact, each of the refluxers has its own threshold value VTH1 (eg vTHla, vTHib, v shame, where a, b, c represent different inverters) and its own set point VSPT2 ( For example, VSPT2a, Vspi^b, Vsp^c). This separation of the critical value and the set point between the different reflux and compressor motors is required to prevent possible instability when multiple inverters attempt to simultaneously control the DC link voltage. The 20 VSD includes an active rectifier 202, which can be a pulse width modulated boost rectifier or other boost rectifier type. The DC link phase 2〇4 is provided to the control signal VDC of the node 4〇〇, which is transmitted to the rectifier control unit 4〇2 and the inverter control unit 404. Control units 402 and 404 receive other control signals in addition to the DC link voltage, but are deleted in the figure for convenience of explanation. The control unit 4〇2 19 1303691 and 404 are typically located inside the VSD compartment, but may also be located inside the control panel 308 or may be separately mounted to different devices. One embodiment of the method for controlling the ferry of the present invention is shown in Figure 5A. The flow pattern 500 generally illustrates one aspect of the method of the present invention, beginning with step 5 502 indicating system startup. After the system is started, it operates in normal operation. As shown in step 504, the precondition is that the mains voltage from the AC power source is close to the nominal mains voltage, in other words, there is no voltage dip, or the mains voltage begins to plummet. The nominal mains voltage, but the current input to the boost rectifier is below the current limit, and the DC link voltage is maintained at the set point of 10 VSTPT1. In step 504a, the boost rectifier adjusts the DC link voltage; in step 504b, the inverter continues to operate as usual to adjust the compressor speed; and in step 504c, the DC link voltage is monitored by the control hardware and the software (refer to 6 figure). Steps 5a-4a-504c may be performed simultaneously or sequentially, as shown in step 504. The sequence shown in Figure 6 is for illustrative purposes only. In the step Deng Xiao, the input current of the 15-liter Μ rectifier is equal to or lower than the read § current limit of the boost rectifier. At step 506, the VDC is compared to a predetermined threshold Vthi. The magnitude of vthi is below the nominal set point of the DC link voltage VsTPT1. For example, if the nominal DC link voltage is Vstpi = 95 〇 V, then vTH1 can be selected to be 9 〇〇 2 〇. If Vdc is lower than VTHi, this indicates that the boost rectifier has reached its current limit and can no longer adjust the DC link voltage to its set value, after which the system proceeds to step 508 (Figures 7 and 8) to unload the compression. The machine 3〇2 makes the boost rectifier 202 and the pre-charging device inoperable, and the transition inverter 2〇6 becomes the control DC link voltage. Otherwise, the system returns to step 5〇4. DC link 20 1303691 Monitoring of the voltage vDC can be carried out continuously or sequentially - triggering the system response, which is indicated here in separate steps. Change in the value of De as shown in Figure 7, step by step
10 15 =一控制單元•以機械方式卸龍縮二= _心_機作動輪葉來達成，於螺桿壓縮機透 ^ 閥來達成，或於離心壓縮機或螺桿_機的排放管線^ =止關於排放管線來達成。如後文朗，經由㈣壓 縮機，馬達所儲存的轉動能被保留用於安渡駕御操作 極少有轉動鎌耗用在急冷器系統3_冷媒貞载。於短日士 間安渡駕御週期期間，儲存於冷媒回路和二次氣化冷浴: 路中的熱能被用來對HVAC&R系統負載提供:需的::;回 於步驟5G8b ’約略同時，升壓整流器則咖變成不能動 作’於步驟麻，與升壓整―相肩的難電裝^成 不能動作。系統現在是在第2相安渡駕御操作的第二階段， 說明於步驟510a-510c。步驟508a-508c可同時進行或循序"進 行010 15 = a control unit • mechanically unloading the second = _ heart _ machine to achieve the wheel to achieve, in the screw compressor through the valve to achieve, or in the centrifugal compressor or screw _ machine discharge line ^ = About the discharge pipeline to achieve. As in the case of the latter, through the (four) compressor, the rotational energy stored by the motor is reserved for the safe operation of the ferry. There is very little rotation loss for the chiller system 3_refrigerant load. Stored in the refrigerant circuit and the secondary gasification cold bath during the short-term inter-duty cycle: The heat in the road is used to provide HVAC & R system load: Required::; Back to step 5G8b 'Approximately at the same time, The booster rectifier is not able to operate in the step of numbness, and it is impossible to operate with the hard-pressing device. The system is now in the second phase of the second phase of the safety control operation, illustrated in steps 510a-510c. Steps 508a-508c can be performed simultaneously or sequentially"
步驟510a-510c也可於步驟508進行。參考第8圖，於步 驟510a中，反流器致力於將直流鏈路電壓調整至名目值 Vstpt2。選用為VsTPT2之值係低於選用為Vthi之值。舉例言 ⑽之，若VTH1為900 V，則VsTPT2可為850 v。反流器係藉反二 控制單元4〇4而作為整流器操作。儲存於馬達1〇6和壓縮 機302的轉動部分的能量於反向流動，從正常馬達的操作， 流經反流器206，流至直流鏈路204。馬達1〇6和壓縮機3〇2 有效變成發電機，供電予直流鏈路。藉此方式，直流鏈路 21 1303691 受到包含馬達106及壓縮機302的機電負載中所儲存的能量 的支援。連接至直流鍵路來儲存電能的電容器（圖巾未顯示) 係藉來自馬達106流經反流！|2〇6的能量而被維持於充電狀 恶。於本發明之本實施例中，於步驟5〇讣，升壓整流器變 5成不犯運作，全部供給直流鏈度的能量係從馬達1〇6及壓縮 機302所儲存的能量通過反流器來提供。如此，直流鏈路2〇4 與輸入電源隔開。於步驟510b，控制硬體和軟體監視直流 鏈路電壓VDC，於步驟51〇c時輸入市電電壓％财〇。於步驟 508 ’步驟510a-510c可同時進行或循序進行，第8圖指示的 10順序僅供舉例說明之用。步驟5〇8持續至下列一種情況發生 於第5A圖所示的步驟512或516。 於步驟512,直流鏈路電壓Vdc連續被監視。若Vdc下降 至低於預定的故障臨界值電壓Vunder (低於Vstpt2)，則指示 系統故障。於步驟514，VSD即刻關機。否則，系統前進至 15步驟516，其中監視於輸入電源的輸入市電電壓VINAC。若 Vinac係大於預定的輸入市電臨界值電壓Vthjn，則指示電 壓驟降的情況不再存在，系統前進至步驟518來復置系統成 為正常操作。如第9圖所示，於步驟518進行步驟518&-5186。 於步驟518a ’於VSD前端的預充電裝置變成可運作來控制 2 Q 义 直流鏈路電壓來升高。於步驟518]3及518(：，升壓整流器開 關變成可運作，來進一步升高直流鏈路電壓至預定值 Vstpti。於步驟518d，反流器控制模式被傳輸回來從接收自 控制面板、微處理器或控制器的命令來控制馬達速度，依 據控制面板所接收到的特定感測器讀取值而定，對VSD 104 22 1303691 ^達106提供最佳操作設定值，直流鏈路再度由整流器控 ，早7L4G2控制。最後，於步驟偷，壓縮機以機械方式載 何。於步驟504，***恢復正常運作。 參考第5_，現在說明安渡駕御序列之較佳實施例。 5於本發明之此一恶樣中，於整個安渡駕御期間，升壓整流 為維持可運作，與再生來自於馬達1〇6的能量同時，供給電 流至直流鏈路202的電容器。此種替代方法的初步步驟搬 至506分別係與前文討論之第5A圖及第6圖所示之步驟相 同。於本發明之另—方法中，若VDC係低於VTH1，則於步驟 1〇 506系統丽進至步驟608 ;否則系統返回步驟5〇4。舉個實 例’若名目直流鏈路電壓為Vstpti = 95〇 V，則可選擇 為900 V。如後文說明，步驟5〇8、516及518係由後述步驟 608、616及618所置換。 步驟508a、510a、608a及510c係於第1 〇圖所示之步驟 15 6仳進行。於步驟508a，壓縮機控制單元406以前述相同方 式以機械方式卸載壓縮機。於步驟510a，反流器控制單元 404開始將直流鏈路電壓Vdc調節至VsTpT2之值，且經由忽略 接收自控制面板、微處理器、或控制器的命令來停止調整 壓縮機馬達106的速度，該命令係依據由控制面板所接收的 20特定感測器讀取值而定，提供VSD 104及馬達1〇6的最佳操 作設定值。VSTp2選用之值係低於對乂則選用之值。舉例古 之’若Vthi為900 V ’則Vstp2為850 V。於步驟608a，於第7 圖所示之方法相反，升壓整流器持續調整直流鏈路至於電 流極限操作的Vstpti值。於步驟608可同時或循序進行步驟 23 1303691 508a、510a及510c，第10圖指示的操作順序僅供舉例說明 之用。 於步驟510a ’反流器係作為整流器來將直流鏈路電壓 調整至預定值Vstpt2。直流鍵路電壓係由傳導通過整流哭/ 5變流器的能量、以及藉由儲存於包含馬達106及壓縮機3〇2 的機電負載中的能量二者所支援。於本較佳實施例中，於 步驟608a，升壓整流器於其電流極限維持主動，也致力於Steps 510a-510c may also be performed at step 508. Referring to Fig. 8, in step 510a, the inverter is dedicated to adjusting the DC link voltage to the nominal value Vstpt2. The value chosen for VsTPT2 is lower than the value chosen as Vthi. For example (10), if VTH1 is 900 V, VsTPT2 can be 850 v. The inverter operates as a rectifier by means of a second control unit 4〇4. The energy stored in the rotating portions of the motor 1〇6 and the compressor 302 flows in the reverse direction, from the operation of the normal motor, through the inverter 206, to the DC link 204. The motor 1〇6 and the compressor 3〇2 effectively become generators and supply power to the DC link. In this manner, DC link 21 1303691 is supported by energy stored in the electromechanical load of motor 106 and compressor 302. A capacitor connected to the DC link to store electrical energy (not shown) flows through the motor 106 through the reverse flow! |2〇6 energy is maintained in a charging state. In the embodiment of the present invention, in step 5, the boost rectifier is changed to 5, and all the energy supplied to the DC link is passed from the motor 1〇6 and the energy stored in the compressor 302 through the inverter. provide. Thus, the DC link 2〇4 is separated from the input power. In step 510b, the control hardware and the software monitor the DC link voltage VDC, and the commercial power voltage % is input at step 51 〇c. Steps 510 'steps 510a-510c may be performed simultaneously or sequentially, and the sequence of 10 indicated by FIG. 8 is for illustrative purposes only. Step 5〇8 continues until one of the following conditions occurs at step 512 or 516 as shown in Figure 5A. At step 512, the DC link voltage Vdc is continuously monitored. If Vdc drops below the predetermined fault threshold voltage Vunder (below Vstpt2), it indicates a system fault. At step 514, the VSD is immediately turned off. Otherwise, the system proceeds to step 516 where the input mains voltage VINAC of the input power source is monitored. If the Vinac system is greater than the predetermined input mains threshold voltage Vthjn, then the condition indicating the voltage dip is no longer present and the system proceeds to step 518 to reset the system for normal operation. As shown in FIG. 9, step 518 & -5186 is performed in step 518. The pre-charging device at the front end of the VSD in step 518a becomes operational to control the 2Q sense DC link voltage to rise. In steps 518] 3 and 518 (:, the boost rectifier switch becomes operational to further boost the DC link voltage to a predetermined value Vstpti. In step 518d, the inverter control mode is transmitted back from the control panel, micro Commands from the processor or controller to control motor speed, depending on the particular sensor reading received by the control panel, provide optimal operating settings for VSD 104 22 1303691 ^ up to 106, and the DC link is again rectified by the rectifier Control, early 7L4G2 control. Finally, in the step stealing, the compressor is mechanically loaded. In step 504, the system resumes normal operation. Referring to Figure 5, a preferred embodiment of the Andu control sequence is now described. In a bad case, during the entire safe driving period, the boost rectifier is maintained to operate, and while regenerating the energy from the motor 1〇6, the current is supplied to the capacitor of the DC link 202. The preliminary steps of this alternative method are moved to 506 is the same as the steps shown in the fifth and sixth figures discussed above. In the other method of the present invention, if the VDC system is lower than VTH1, then the system is in step 1〇506. Go to step 608; otherwise the system returns to step 5〇4. For an example, if the nominal DC link voltage is Vstpti = 95〇V, it can be selected as 900 V. As explained later, steps 5〇8, 516 and 518 are The steps 508a, 510a, 608a, and 510c are performed in step 15 6仳 shown in Fig. 1. In step 508a, the compressor control unit 406 is mechanically performed in the same manner as described above. The compressor is unloaded. At step 510a, the inverter control unit 404 begins to adjust the DC link voltage Vdc to a value of VsTpT2 and stops adjusting the compressor motor by ignoring commands received from the control panel, microprocessor, or controller. The speed of 106, the command is based on the 20 specific sensor readings received by the control panel, providing the optimal operating settings for the VSD 104 and the motor 1〇6. The value selected for VSTp2 is lower than the 乂The value chosen is as follows. For example, if Vthi is 900 V, then Vstp2 is 850 V. In step 608a, in contrast to the method shown in Figure 7, the boost rectifier continuously adjusts the Vstpti value of the DC link to the current limit operation. At step 608 Steps 23 1303691 508a, 510a, and 510c are performed simultaneously or sequentially, and the sequence of operations indicated in FIG. 10 is for illustrative purposes only. In step 510a 'the inverter is used as a rectifier to adjust the DC link voltage to a predetermined value Vstpt2. The key voltage is supported by both the energy conducted through the rectified crying/5 converter and the energy stored in the electromechanical load including motor 106 and compressor 3〇2. In the preferred embodiment, In step 608a, the boost rectifier is actively active at its current limit, and is also committed to
10 1510 15
20 調節直流鏈路電壓，但係調節至VSTPT1的較高設定點。於電 流極限操作可防止升壓整流器實際上免於於其輸出達到 VSTPT1。當輸入交流電壓升高至足夠幅度時，主動整流器供 給足夠能量俾允許達成VSTPT1。換言之，當於電餘限操作 時’升壓整流n的電壓控伽路為飽和（當升壓整流器和反 流器二者以閉路回路操作試圖控制直流鏈路電壓時，如此 可防止系統不穩定），但電力仍然持續從輸人交流市電流入 直流鏈路。如此電力係從輸人電壓源經由變流器而供給直 流鏈路階段；以及從負載經由反流“供給直流鍵路階 段，允許於電壓驟降期間維持最大能量，如此最大化系統 的安渡駕祕力。另-種方料前進至如社第5A圖說明 之步驟512，也顯示於第5B圖，直到到達步驟616為止。於 步驟616 ’ VDG與VTH1極限比較，做決策判定來是否迴圈返 回第2相操作，或於步細停止安渡駕御操作。若I係大 於VTH1，則主動整流器不再於電流極限操作，指示輸入市 電=壓已經回復至額定市電轉的财百分比以内，且反 流器控制單元已__純至㈣吨、微處理器、或 24 1303691 控制器的命令回復控制馬達106的速度，騎令係依據控制 面板e所接收的特定感測器讀取值而定，對VSD關口馬達 ⑽提供最佳騎奴值，於步驟618，以機械方式載入壓 縮機302。然後於步驟，系統恢復常規操作。 5 雖然較佳控制演繹法則係於電腦程式實施，且係由位 在於VSD 1G4的微處理器來執行，但須了解，控制演绎法則 可由熟諳技藝人士使用數位硬體及/或類比硬體來實作與 執仃。若使用硬體來執行控制演繹法則，則VSD 1()4的相對 應組態可改變來結合需要的元件，以及去除任何不再需要 10 的元件。 於根據本發明之又另一個方法中，VSD 104的變流器 202可為被動整流器，換言之，二極體整流器或閘流體整流 益來將直流鏈路階段的交流輸入電力轉成直流電力。雖然 使用被動整流器/變流器2〇2之方法提供的安渡駕御能力比 15主動整流器/變流器方法小，但由於卸載冷媒負荷，且從馬 達7壓縮機負載再生能量至直流鏈路204仍舊可達成改良的 安渡駕御。當使用被動整流器時實作第5圖所示方法，於步 驟508,有效開始安渡駕御，其中直流鏈路電壓已經衰減至 低於臨界值電壓VTH1。於第7圖步驟508b和於第9圖步驟 20 518b，採行動作朝向被動整流器而非主動整流器。於此種 情況下，直流鏈路電壓無法經由輸入變流器來控制於特定 設定點諸如VSTP1，反而直流鏈路電壓幅度為輸入交流市電 電壓的被動整流之函數。於此種情況下，Vthi的幅度被選 擇為於系統的操作輸入電壓範圍，VTH1係低於由輸入市電 25 1303691 電壓整流所得的最低預期的直流電壓。vSTPT2係選用為低於 VtH1，反流器控制單元404於電壓驟降期間調整直流鏈路電 壓V〇c之VsTPT2之值0 再度參考第3圖’有多種裝置可用來實作麼縮機302的 5 機械卸載。預轉輪葉303以虛線指示來表示只可應用於離心 壓縮機302。預轉輪葉303係耦接至離心壓縮機3〇2的壓縮機 進氣口。預轉輪葉303可操作來改變壓縮機3〇2的負載。較 佳，可採用咼速致動器（圖中未顯示）來響應於電力的驟降而 快速關閉預轉輪葉303。同理，當壓縮機為螺桿壓縮機時， 10滑閥303可如同離心壓縮機配置中的預轉輪葉3〇3，可用來 改、麦負載。滑閥303係以虛線指示表示只應用於螺桿壓縮 機。滑閥303的高速致動器也較佳，俾允許系統來快速響應 於電壓驟降。當出現電M驟降時，藉由關閉預轉輪葉3〇3可 達成壓縮機的機械卸載。 15 帛3圖也顯示止回閥3 〇 5***於壓縮機的排放管線3 〇 7 中。另外，止回閥305可***壓縮機3〇2的抽取管線3〇1中。 止回閥3〇5的操作可免除急冷器控制系統的動作來造成壓 縮機以機械方式產生負载的需求，換言之，止回閥305可免 除冋速作動$置的需求’例如螺桿壓縮機中的滑閥或離 2〇心壓縮機的預轉輪葉303的需求。止回閥305也可最小化壓 、縮機302的機械卸載時間。於另一個實施例中，可刪除止回 闕305❿可使用預轉輪葉或滑閥來機械卸載壓縮機 3〇2。止回閥305可單獨使用，或組合其它型別的機械卸載 裝置之一而使用。 26 1303691 如此快速機械卸載壓縮機用於離心壓縮機用途特別有 利’原因在於系統正常係於壓縮機湧浪邊緣操作。壓縮機 /勇浪係發生於急冷器系統的冷媒流相對於離心推進器來逆 轉方向時。若壓縮機302係於湧浪點或接近湧浪點操作，則 5壓縮機操作速度的下降將造成壓縮機3〇2進入潘浪區。此種 操作速度的降低係根據安渡駕御演繹法則來實作，如前文 就第5圖至第1〇圖說明。***於壓縮機3〇2的排放管線的止 回閥305可防止冷媒氣體的逆流，如此防止壓縮機3〇2的湧 /良狀況。§推進裔的轉速降低時，止回閥3〇5關閉，原因在 1〇於排放管線内部被加壓的冷媒氣體即刻開始藉由逆流來平 衡壓力。與止回^關閉的同時，卸載壓缩機***，如此最 大化旋轉系統中能量的儲存，且擴大系統的安渡駕御能力。 當輸入交流電力102係回復至名目時，壓縮機推進器的 RPM回復至額定操作RPM。然後壓縮機排放管線3〇7的壓力 15經控制且返回額定位準，迫使止回閥305開啟，系統的機械 負載回復至電壓驟降之前的數值。 本發明之系統及方法無需感測馬達速度來監視與響應 電壓驟降情況，可降«統成本且提供线的可信度^ 過感測直流鏈路電壓、輸入交流市電電壓、輸入電流和馬 20 達電流可達成控制。 雖然已經參照較佳實施例來說明本發明，但熟諳技藝 人士須了解可未棒離本發明之範圍做出多項變化且可以相 當研究來取代本發明之研究。此外，可未恃離本發明之主 要範圍，做出多項調整來讓特定情況或材料配合本發明之 27 1303691 教示。因此，本發明絕非意圖囿限於揭示作為執行本發明 之最佳模式的特定實施例，反而本發明含括落入隨附之申 請專利範圍内的全部實施例。 • 【圖式簡單說明】 • 5 第1圖示意顯示本發明之概略系統組態。 第2圖示意顯示用於本發明之可變速驅動器之一個實 施例。 第3圖示意顯示可用於本發明之一種冷凍系統。 # 第4圖顯示本發明之簡化方塊圖。 10 第5A圖顯示本發明之一實施例之流程圖。 第5B圖顯示本發明之一較佳實施例之流程獨。 第6圖至第9圖顯示第5A圖所示流程圖之部分。 第10圖顯示第5B圖之流程圖之部分。 【主要元件符號說明】 102.. .交流電源20 Adjusts the DC link voltage, but adjusts to the higher set point of VSTPT1. Operation at the current limit prevents the boost rectifier from actually getting its output to VSTPT1. When the input AC voltage rises to a sufficient amplitude, the active rectifier supplies enough energy to allow VSTPT1 to be reached. In other words, when the voltage is limited, the voltage-controlled gamma of the step-up rectification n is saturated (when both the boost rectifier and the inverter operate in closed-loop operation to try to control the DC link voltage, this prevents system instability. ), but the power continues to flow from the input city to the DC link. Such power is supplied to the DC link phase from the input voltage source via the converter; and from the load via the reverse flow "feed DC link phase, allowing maximum energy to be maintained during the voltage dip, thus maximizing the system's safety The other method advances to step 512 as illustrated in Figure 5A, and is also shown in Figure 5B until step 616 is reached. In step 616 'VDG is compared with the VTH1 limit, a decision is made to determine whether to return the loop. The second phase operation, or the step to stop the safety control operation. If the I system is greater than VTH1, the active rectifier is no longer operated at the current limit, indicating that the input mains = pressure has returned to the nominal percentage of the commercial power, and the inverter The control unit has __pure to (four) tons, microprocessor, or 24 1303691 controller command to restore the speed of the motor 106, depending on the specific sensor read value received by the control panel e, to the VSD The gateway motor (10) provides the optimum rider value and is mechanically loaded into the compressor 302 in step 618. The system then resumes normal operation in steps. 5 Although the preferred control algorithm is The computer program is implemented by a microprocessor located in VSD 1G4, but it should be understood that the control deductive rule can be implemented and executed by skilled artisans using digital hardware and/or analog hardware. To perform the control deduction rule, the corresponding configuration of VSD 1() 4 can be changed to combine the required components, and remove any components that no longer need 10. In yet another method according to the present invention, the VSD 104 is changed. The flow device 202 can be a passive rectifier, in other words, a diode rectifier or a thyristor rectifying device converts the AC input power of the DC link phase into DC power, although the Amway is provided using a passive rectifier/converter 2〇2 method. The control capability is smaller than that of the 15 active rectifier/converter method, but the improved safety control can still be achieved due to the unloading of the refrigerant load and the regenerative energy from the motor 7 compressor load to the DC link 204. When using the passive rectifier, the fifth implementation is implemented. The method shown in the figure, in step 508, effectively begins to control the ride, wherein the DC link voltage has decayed below the threshold voltage VTH1. In step 508b of FIG. Step 20 518b of Figure 9, the picking action is toward the passive rectifier instead of the active rectifier. In this case, the DC link voltage cannot be controlled via the input converter to a specific set point such as VSTP1, but the DC link voltage amplitude is Enter the function of passive rectification of the AC mains voltage. In this case, the amplitude of Vthi is chosen to be within the operating input voltage range of the system, and VTH1 is lower than the lowest expected DC voltage obtained by rectifying the input mains voltage 25 1303691. vSTPT2 The value of VsTPT2 is adjusted to be lower than VtH1, and the inverter control unit 404 adjusts the DC link voltage V〇c during the voltage dip. 0 Referring again to FIG. 3, there are various devices that can be used to implement the reduction machine 302. Mechanical unloading. The pre-rotation vanes 303 are indicated by dashed lines to indicate that they are only applicable to the centrifugal compressor 302. The pre-rotation vane 303 is coupled to the compressor intake port of the centrifugal compressor 3〇2. The pre-rotation vanes 303 are operable to vary the load of the compressor 3〇2. Preferably, an idle actuator (not shown) may be employed to quickly close the pre-rotation vanes 303 in response to a sudden drop in electrical power. Similarly, when the compressor is a screw compressor, the 10 spool valve 303 can be used as a pre-rotating vane 3〇3 in a centrifugal compressor configuration, which can be used to change the load of the wheat. The spool valve 303 is indicated by a broken line indicating that it is applied only to the screw compressor. High speed actuators for spool valve 303 are also preferred, allowing the system to respond quickly to voltage dips. When an electric M dip occurs, the mechanical unloading of the compressor can be achieved by closing the pre-rotating vanes 3〇3. The 15 帛3 diagram also shows that the check valve 3 〇 5 is inserted in the discharge line 3 〇 7 of the compressor. In addition, the check valve 305 can be inserted into the extraction line 3〇1 of the compressor 3〇2. The operation of the check valve 3〇5 eliminates the need for the operation of the chiller control system to cause the compressor to mechanically generate a load. In other words, the check valve 305 can eliminate the need for idle operation, such as in a screw compressor. The need for a spool or pre-rotation vane 303 from the 2 centroid compressor. The check valve 305 also minimizes the mechanical unloading time of the press and compressor 302. In another embodiment, the checkback 阙305 can be deleted to mechanically unload the compressor 3〇2 using a pre-rotation vane or spool. The check valve 305 can be used alone or in combination with one of the other types of mechanical unloading devices. 26 1303691 Such a fast mechanical unloading compressor is particularly advantageous for use in centrifugal compressors because the system is normally operated at the edge of the compressor surge. Compressor / Yonglang occurs when the refrigerant flow in the chiller system is reversed relative to the centrifugal thruster. If the compressor 302 is operating at or near the swell point, a decrease in the operating speed of the compressor 5 will cause the compressor 3〇2 to enter the Pan wave zone. This reduction in operating speed is based on the Andu's Law of Deduction, as explained in the previous section from Figure 5 to Figure 1. The check valve 305 inserted into the discharge line of the compressor 3〇2 prevents the reverse flow of the refrigerant gas, thus preventing the surge/good condition of the compressor 3〇2. § When the speed of the propulsion is lowered, the check valve 3〇5 is closed because the refrigerant gas pressurized inside the discharge line immediately starts to balance the pressure by countercurrent. At the same time as the checkout is turned off, the compressor system is unloaded, thus maximizing the storage of energy in the rotating system and expanding the system's ability to withstand the ride. When the input AC power 102 is returned to the name, the RPM of the compressor thruster returns to the rated operational RPM. The pressure 15 of the compressor discharge line 3〇7 is then controlled and the return amount is positioned, forcing the check valve 305 to open and the mechanical load of the system to return to the value before the voltage dip. The system and method of the present invention does not require sensing motor speed to monitor and respond to voltage dips, can reduce cost and provide line reliability ^ sense DC link voltage, input AC mains voltage, input current, and horse 20 current can be achieved. While the invention has been described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention. Therefore, the invention is not intended to be limited to the specific embodiments disclosed as the preferred embodiment of the invention. • [Simple description of the diagram] • 5 Figure 1 shows schematically the schematic system configuration of the present invention. Figure 2 is a schematic view showing an embodiment of a variable speed drive for use in the present invention. Figure 3 is a schematic representation of a refrigeration system useful in the present invention. #图4 shows a simplified block diagram of the present invention. 10 Figure 5A shows a flow chart of an embodiment of the present invention. Figure 5B shows the process flow of one preferred embodiment of the present invention. Figures 6 through 9 show portions of the flow chart shown in Figure 5A. Figure 10 shows a portion of the flow chart of Figure 5B. [Main component symbol description] 102.. . AC power supply
104.. .可變速驅動器、VSD 106.. .馬達 202.. .整流器/變流器階段 204.. .直流鏈路階段 206.. .反流器階段 300.. .冷;東系統 302.. .壓縮機 303.. .負載改變裝置、預轉輪 葉、進氣口導件輪葉、滑閥 304.. .冷凝器 305···止回閥 306.. .氣化器 307.. .排放管線 308.. .控制面板 400.. .節點 402···整流器控制單元 404…反流器控制單元 406.. .壓縮機控制單元 500.. .流程圖 502-518、608、616、618···步驟 28104.. Variable Speed Drive, VSD 106.. Motor 202.. Rectifier/Converter Stage 204.. DC Link Phase 206.. Inverter Stage 300.. .cold; East System 302. . Compressor 303.. Load change device, pre-rotation vane, intake guide vane, slide valve 304.. condenser 305··· check valve 306.. . gasifier 307.. Discharge line 308.. Control panel 400.. Node 402··Rectifier control unit 404...Inverter control unit 406.. Compressor control unit 500.. Flowchart 502-518, 608, 616, 618···Step 28