427049 經濟部中央標準局員工消費合作牡印繁 Α7 Β7 五、發明说明（1 ) 本發明是關於脈寬調變馬達驅動器中變頻器電流之感 測’用於馬達的向量控制，更具體而言，是關於在不使用 霍爾感知器的情形下該電流之感測。 高性能馬達驅動器要求馬達電流波形能被感測且回授 到脈寬調變控制器。最常用來取得必要電流回授信號的方 法是從與馬達繞組相串聯之霍爾感知轉換器而來，霍爾感 知轉換器不僅體積龐大且價格昂貴，所以希望能找到可達 成此一功能的其他方法。 其中一種替換方式是只裁測變頻器的輸入電流，而不 是三個輸出電流，接著使用供變頻器内之開關用的脈寬調 變時序訊號作用在該單一電流波形上，藉以重建代表馬達 電流的三個電流波形；此種配置顯示在第1A圖中 由該變頻器的輸入電流重建馬達電流的作法，然而， 不會有馬達向量控制所需的準確度》如在第1Β圖中所示 者’成一個給定馬達相位的電流’只能以該等變頻器開關 的八種可能狀態中的二種精確地定義出來。該等重建的馬 達電流波形中所遺失的片段可由計算補回，但並不完全精 確。 另外一種方法提供向量控制所需的準確度，它是經由 安排成與下方三個變頻器開關的每一個相串聯的電流檢視 電阻器20至22取得之訊號，來重建馬達電流波形；此種配 置顯示於第2Α圖中。 如第2Β圖所示，此種配置之任何給定馬達相位的電 流，對該等變頻器開關的八種可能狀態中的五種為已知； 本紙張尺度適用中國國家標準（CNS > A4規格（210X297公董） . 裝 訂 J (請先閱讀背面之注意事項再填寫本頁) -4- 427049 經濟部中央標準局負工消費合作社印装 Λ 7 Β7 五、發明説明（2 ) 遺失的片段可由計算補回至足夠的準禮度。 然而’電流檢視電阻器有其缺點，就是它們會消耗功 率；而且，當該驅動器額定功率增加時，通過電流檢視電 阻器的雜訊突波也會增加，此乃肇因於感抗對電阻之比率 (L/R)增加；所以一個用來移除雜訊突波的濾波器是必要 的，而且這也會減慢響應時間和增加故障反應時間；另一 個缺點是電流檢視電阻器不提供隔離訊號。基於這種種因 素’在某些馬達電流上電流檢視電阻器即變得不實用。 依照本發明’係提供新穎的排列以感測個別的變頻器 開關電流，其使用傳統交流比流器或使用R〇g〇ws]d磁通 感測線圏：後者的解決方式特別人引人注意，因為它並不 需要任何磁性鐵心材料。 前述每一種解決方式都避免使用霍爾感測器，本質上 是無損失的，而且提供隔離的快速回授訊號；前述的概念 結合了電流感測元件的操作特性到脈寬調變變頻器的操作 特性；經由整合電流感測元件的操作模式到變頻器的操作 模式中’在包括零的任何變頻器輪出頻率下，均可傳遞代 表開關電流的隔離電流訊號’基本電流感測元件本身的固 有低頻限制’當其被使用當成單獨的零件時，即被迴避掉 〇 經由以下參考相關的圖面對本發明的說明，本發明的 其他特徵和優點將會變得很明顯。 本發明現在將會參考下列圖面更詳細的敘述在以下細 部說明中，其中： 本紙張尺度適用中國國家標準（CNS ) A4規格{ 210X297公釐） ^----1 (請先閎讀背面之注意事項再填寫本頁) 訂 -5- 經濟部中夬標準局員工消費合作社印製 427049 A 7 B7 — -——— _ 五、發明説明（3 ) 第1A圖顯示一個已知的配置，其中變頻器的輪入電 流被感測到；且第IB圖顯示當變頻器輪入電流如在第玉A 圖中所示地被感測時輸出電流已知的可能變頻器開關狀態 t 第2A圖顯示一個已知的配置，其中三個各別的變頻 器開關電流被感測到，且第2B圖顯示輸出相電流已知的 可能變頻器開關狀態； 第3A圖是一張電路圖，其中_個交流比流器依照本 發明的一個實施例被用來感測變頻器開關電流；且第3β 圖是第3A圖所示電路的一張時序圖； 第4A圖是一張電路圖’其中依照本發明的另一個實 施例’ Rogowski線圈是用來感測變頻器開關電流，且第4B 圖是第4A圖所示電路的一幅時序圖； 第5圖是一張電路圖’顯示第3A圖所示電路對於全馬 達電流的感測的應用； 第6圖是一張電路圖，顯示第4A圖所示電路對於全馬 達電流的感測的一種改造型態。 依照本發明使用一個交流比流器來感測變頻器開關電 流的第一個較佳實施例，係顯示在第3A圖中，相關的電 流和電壓波形則顯示在第3B圖中。 一旦相關的絕緣閘雙極電晶體變頻器開關34導通，變 頻器開關電流就會通過比流器32的一次侧繞组；比流器32 就會在正常狀態下運作，經由它的二次侧繞板傳遞一個正 比於變頻器開關34中之電流的輸出訊號，此訊號相對於變 本紙乐尺度通用中國國家標準（CNS > A4規格（2丨〇><297公釐） -6- (請先閲讀背面之注意事項再填寫本買) 訂 427049 經濟部中央標準局負工消費合作社印製 A7 B7 五、發明説明（4 ) 頻器電流的兩極性，換言之，相對於流經絕緣閘雙極電晶 體34A或二極體34B的電流，均和變頻器開關電流成正比 :雖然比流器32如圖所示係連接到變頻器開關的輸出端， 但疋當其替換成連接到輸入端時，比流器仍會傳遞一個類 似的輸出訊號。 當變頻器開關34關閉，訊號生成電阻器39被交流開關 37和38從比流器32的輸出端切離，此等開關是受第沾圖 所示的脈寬調變時序訊號所驅動；該脈寬調變訊號亦驅動 變頻器開關；在變頻器開34關閉時切斷電阻器39，並不 會損及跨在此電阻器上之訊號，因為依據定義，在該時段 中沒有變頻器開關電流產生。 在此關閉的時段中，在比流器二次侧繞蚯的磁化電流 被跨在一對箱位稽納二極體35和36上生成的飛返電壓驅動 至零：這對稽納二極體具有遠比跨在電阻器39上的正常訊 號電壓更高的崩潰電壓，而可在開關關閉時間裏促進磁通 完全地重新安排’甚至在關閉時間遠比導通時間短時亦然 ，然而，若關閉時間是如此短暫，以致磁通的完全重新安 排不會發生’則短暫的重新安排時間無實際結果，因為一 完全地重新安排將會發生在隨後較長的關閉時段中。 藉由以上說明的電路’比流器即針對每一個新的開關 電流區段被更新且準備妥當，基本上都以零磁通開始；因 此，代表開關電流之一連串連績的單向輸出訊號，即可產 生在電阻器39上，同時比流器32鐵心内的磁通好好地保持 在磁飽和值以下時，如第3B圖所示者。 本紙張尺度適用中國國参標準（CNS ) A4規格（2ΐ〇χ297公爱） —J------—^------,玎------.^ (請先閲讀背面之注意事項再.填寫本頁) -7 經濟部中央標準局員工消費合作杜印製 Α7 _ Β7 五、發明説明（5 ) 使用Rogowski線圈來感測變頻器開關電流的第二個 較佳實施例，係顯示於第4A圖中；在此，Rogowski線圈 如圖示連接到變頻器開關的輸出端，但亦可替換式地連接 到輸入端；Rogowski線圈42本質上是一個空氣鐵心式線 圈磁通感測器’且傳遞正比於由變頻器開關44供應的一次 側電流之di/dt的一個輸出訊號：包含一個運算放大器47、 一個電阻器48和一個電容器46的一個積分器41，接著用來 傳遞一個代表變頻器開關電流的訊號。 原則上，若積分器41是理想的，且因此沒有偏差或漂 移，該積分器將會傳遞一個完全正比於變頻器開關電流的 連續輪出訊號；然而，實際上，偏差和漂移會無法避免地 存在，而且當積分器處於自由運作狀態時，會導致積分器 的餐出在低輸出頻率下有無法接受的誤差。 此第二個實施例的一個優點就是此項問題係使用重設 器45在相關變頻器開關的關閉時段中，重設和保持積分器 的輸出為零，而予以克服；因為該積分器的輪出在這段期 間内無論如何應該都是零，該積分器的每一次重新設定提 供小但有意義的校正動作，將積分器拉回進入校正狀態 且確保正確。 因此’積分器漂移不能建立，甚至當該變頻器輸出頻 率為零之時亦然；然後，該積分器的輸出即不含偏差地忠 實再現變頻器開關電流。 有利地，第3圖的配置可輕易地達成，而且提供一個 較使用霍爾轉換器更小的電路且更便宜的解決方式。 本紙張尺度適用中國 IJ - 訂 I ^ (請先閱讀背面之注意事項再填寫本頁) -8 -427049 Consumer cooperation of Central Standards Bureau of the Ministry of Economic Affairs of the People's Republic of China A7 B7 V. Description of the invention (1) The invention relates to the sensing of the inverter current in a PWM motor driver 'for vector control of a motor, more specifically Is about the sensing of this current without using a Hall sensor. High-performance motor drivers require motor current waveforms to be sensed and fed back to the PWM controller. The most commonly used method to obtain the necessary current feedback signal is from a Hall sensor converter connected in series with the motor winding. The Hall sensor converter is not only bulky and expensive, so I hope to find another one that can achieve this function. method. One alternative is to only measure the input current of the inverter instead of the three output currents, and then use the pulse width modulation timing signal for the switches in the inverter to act on the single current waveform to reconstruct the representative motor current Three current waveforms; this configuration shows the method of reconstructing the motor current from the input current of the inverter in Figure 1A, however, there will not be the accuracy required for motor vector control "as shown in Figure 1B The 'current into a given motor phase' can only be precisely defined in two of the eight possible states of the inverter switches. The missing segments in these reconstructed motor current waveforms can be replaced by calculations, but they are not completely accurate. Another method provides the accuracy required for vector control, which is to reconstruct the motor current waveform via the signals obtained by current viewing resistors 20 to 22 arranged in series with each of the three inverter switches below; this configuration Shown in Figure 2Α. As shown in Figure 2B, the current of any given motor phase in this configuration is known to five of the eight possible states of these inverter switches; this paper size applies the Chinese National Standard (CNS > A4 Specifications (210X297 public director). Binding J (please read the notes on the back before filling this page) -4- 427049 Printed by the Central Standards Bureau of the Ministry of Economic Affairs, Consumer Cooperatives Λ 7 Β7 V. Description of the invention (2) Missing clips It can be compensated by calculation to a sufficient degree of courtesy. However, 'current viewing resistors have the disadvantage that they consume power; and, as the driver's rated power increases, the noise surges through the current viewing resistors also increase. This is due to the increase in the ratio of inductive reactance to resistance (L / R); so a filter to remove noise surges is necessary, and this will also slow down the response time and increase the fault response time; Another disadvantage is that the current-viewing resistor does not provide an isolated signal. Based on these factors, 'the current-viewing resistor becomes impractical at certain motor currents. According to the present invention, a novel arrangement is provided. In order to sense the switching current of individual inverters, it uses traditional AC current transformers or uses magnetic flux sensing lines. The latter solution is particularly attractive because it does not require any magnetic core. Materials. Each of the aforementioned solutions avoids the use of Hall sensors, which are essentially lossless and provide isolated fast feedback signals; the aforementioned concepts combine the operating characteristics of current sensing elements to pulse-width modulated frequency conversion The operating characteristics of the converter; by integrating the operating mode of the current sensing element into the operating mode of the inverter 'at any inverter output frequency including zero, the isolated current signal representing the switching current can be transmitted' the basic current sensing element The inherent low-frequency limitation of itself is avoided when it is used as a separate part. Through the following description of the present invention with reference to the related drawings, other features and advantages of the present invention will become apparent. Now it will be described in more detail in the following detailed description with reference to the following drawings, among which: This paper size applies to the Chinese National Standard (CNS) A4 specifications {210X297 mm) ^ ---- 1 (Please read the precautions on the back before filling out this page) Order-5- Printed by the Consumers' Cooperative of the China Standards Bureau of the Ministry of Economic Affairs 427049 A 7 B7 — -—— — _ V. Description of the invention (3) Figure 1A shows a known configuration in which the drive-in current of the inverter is sensed; and Figure IB shows when the drive-in current of the inverter is as shown in Figure JA Possible frequency converter switching states with known output current when the ground is sensed. Figure 2A shows a known configuration where three separate frequency converter switching currents are sensed, and Figure 2B shows the output phase current. Known possible inverter switching states; Figure 3A is a circuit diagram in which _ AC current converters are used to sense the switching current of the inverter according to an embodiment of the present invention; and Figure 3β is shown in Figure 3A Figure 4A is a timing diagram of the circuit; Figure 4A is a circuit diagram 'wherein according to another embodiment of the present invention' Rogowski coil is used to sense the switching current of the inverter, and Figure 4B is the circuit shown in Figure 4A A timing diagram; Figure 5 is a circuit diagram 'shows 3A The circuit shown for the full application of the sensed motor current; FIG. 6 is a circuit diagram showing a circuit of a full transformation patterns for sensing motor current shown in FIG. 4A. The first preferred embodiment using an AC current transformer to sense the switching current of the frequency converter according to the present invention is shown in Figure 3A, and the related current and voltage waveforms are shown in Figure 3B. Once the related insulated gate bipolar transistor inverter switch 34 is turned on, the inverter switching current will pass through the primary winding of the current transformer 32; the current transformer 32 will operate in the normal state through its secondary side An output signal that is proportional to the current in the switch 34 of the inverter is transmitted around the board. This signal is relative to the standard Chinese national standard (CNS > A4 (2 丨 〇 > < 297 mm)) of the paper scale. (Please read the precautions on the back before filling in this purchase) Order 427049 Printed by the Central Standards Bureau of the Ministry of Economic Affairs and printed by the Consumer Cooperative A7 B7 V. Description of the invention (4) The polarities of the frequency of the inverter current, in other words, relative to flowing through the insulation gate The current of the bipolar transistor 34A or the diode 34B is directly proportional to the switching current of the inverter: Although the current transformer 32 is connected to the output of the inverter switch as shown in the figure, when it is replaced by the input When the inverter switch 34 is turned off, the signal generating resistor 39 is cut off from the output terminal of the current divider 32 by the AC switches 37 and 38. These switches are subject to the The pulse shown in the picture Driven by the wide-modulation timing signal; the pulse-width modulation signal also drives the inverter switch; cutting off the resistor 39 when the inverter is turned on and off 34 will not damage the signal across this resistor, because the basis By definition, no inverter switching current is generated during this period. During this closed period, the magnetizing current wound on the secondary side of the current transformer is generated across a pair of bin audit diodes 35 and 36 Flyback voltage driven to zero: this pair of zener diodes has a much higher breakdown voltage than the normal signal voltage across resistor 39, and can facilitate a complete rearrangement of the magnetic flux during the switch-off time, even in the The off time is much shorter than the on time, however, if the off time is so short that a complete rescheduling of the magnetic flux will not occur, then the short rescheduling time has no practical result because a complete rescheduling will occur In the subsequent longer turn-off period, the circuit 'current ratior' described above is updated and prepared for each new switching current segment, and basically starts with zero magnetic flux; therefore, the generation A series of successive unidirectional output signals of the switching current can be generated on the resistor 39 while maintaining the magnetic flux in the core of the current transformer 32 below the magnetic saturation value, as shown in Figure 3B. Paper size is applicable to China National Ginseng Standard (CNS) A4 specification (2ΐ〇χ297 公 爱) —J ------— ^ ------, 玎 ------. ^ (Please read the back first Please pay attention to this. Fill in this page) -7 Printed by the staff of the Central Bureau of Standards of the Ministry of Economic Affairs of the People's Republic of China Duan A7 _ B7 V. Description of the Invention (5) The second preferred embodiment of using Rogowski coils to sense the switching current of the inverter It is shown in Figure 4A. Here, the Rogowski coil is connected to the output of the inverter switch as shown, but it can also be connected to the input. The Rogowski coil 42 is essentially an air-core coil magnetic flux. Sensor 'and transmits an output signal proportional to the di / dt of the primary current supplied by the inverter switch 44: an integrator 41 including an operational amplifier 47, a resistor 48 and a capacitor 46, and is then used to Pass a signal representing the switching current of the frequency converter. In principle, if the integrator 41 is ideal, and therefore there is no deviation or drift, the integrator will transmit a continuous wheel output signal that is completely proportional to the switching current of the frequency converter; however, in reality, the deviation and drift will unavoidably Exists, and when the integrator is in a free-running state, it will cause unacceptable errors in the output of the integrator at low output frequencies. One advantage of this second embodiment is that this problem is overcome by using the resetter 45 to reset and maintain the output of the integrator to zero during the off period of the relevant inverter switch; Since it should be zero anyway during this period, each reset of the integrator provides a small but meaningful correction action, pulling the integrator back into the correction state and ensuring correctness. Therefore, the integrator drift cannot be established even when the inverter output frequency is zero; then, the output of the integrator faithfully reproduces the inverter switching current without deviation. Advantageously, the configuration of Figure 3 can be easily achieved and provides a smaller circuit and a cheaper solution than using a Hall converter. This paper size applies to China IJ-Order I ^ (Please read the notes on the back before filling this page) -8-
五、發明説明（6 ) 經濟部令央標準局員工消費合作社印製 再者’第4圖的配置也是引人注目的，因為其中沒有 使用磁性鐵心；Rogowski線圈也是較比流器更容易且便 宜地來製造’而且可在機械上更適合於一個小而密實的馬 達控制器驅動電力列總成》V. Description of the invention (6) The layout of Figure 4 printed by the Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs is also noticeable because it does not use a magnetic core; Rogowski coils are also easier and cheaper than flow generators. "Made to ground" and can be mechanically more suitable for a small and compact motor controller to drive the power train assembly. "
Rogowski線圈也可被纏繞在一個直的可撓非磁性結 構上；然後整個線圈移開’接下來繞著一次側導體管曲。 有快速迴轉率的一個南品質積分器，也較佳地被使用 〇 第5和6圖顯不出分別出現在第3和4圖的實施例如何能 夠擴大到提供全馬達電流感測；第5圖顯示一個使用第3圖 之感測電路的調適型態，其中使用了交流比流器；而第6 圖顯示一個使用第4圖之感測電路的調適型態，其中使用 了 Rogowski線圈。 如第5圖所示，各別的感測電路針對電橋支路的上方 和下方絕緣閘雙極電晶體變頻器開關50和52中之每一個被 使用；當變頻器開關50導通時，電流通過比流器54的一次 侧繞組’其二次側繞組傳遞一個正比於流經變頻器開關5〇 之電流的輸出訊號到訊號生成電阻器68 ;此訊號在供應給 上方絕緣閘雙極電晶體變頻器開關5〇的脈寬調變訊號關閉 時’被交流開關64和66切離無法到達電阻器68。 相同地’當下方的絕緣閘雙極電晶體變頻器開關52導 通時’電流通過比流器56的一次側繞組，且比流器56傳遞 一個經由其二次側繞組的輸出訊號到電阻器68，該訊號正 比於相關變頻器開關内的電流；該輪出在供應到下方變頻 本紙張尺度適用中國國家揉準（CNS ) A4規格{ 210X2S»7公釐） --------------裝--^-----^訂-------^--- (請先閲讀背面之注項再填寫本頁) -9- 427049 A7 _ B7 五、發明説明（7) 器開關52的脈寬調變訊號處在關閉狀態時，被交流開關6〇 和62切離無罄到達電阻器68 ;該兩個感測電路的輸出因此 在該支路的輸出處，被組成來傳遞的一個忠實馬達電流再 現結果。 經濟部中央標準局員工消贄合作社印掣 ^^^1 ^^^1 ^^^1 ^^^1 I m - is — UK -*d Λ"，-* c請先閱讀背面之注意事項再填寫本頁) 如上述’第6圖所示的電路使用各別的ROg0wski線圈 感測電路在電橋支路之上方和下方絕緣閘雙極電晶體變頻 器開關70和72中之每一者中；在此，R0g0wski線圈74傳 遞一個正比於由上方的變頻器開關70所供應之一次侧電流 之di/dt的輸出電壓’且R〇g〇wski線圈76對於下方的變頻器 開關72傳遞一個類似的輸出電壓；運算放大器88、電容器 84和電阻器86構成的一個積分器用來傳遞一個代表上方變 頻器開關電流的訊號’且運算放大器89、電容器85和電阻 器87構成的一個積分器傳遞一個代表下方變頻器開關電流 的相對應訊號；有利地是，重設器82和83在供應給每一個 上方和下方變頻器開關70及72之個別脈寬調變訊號關閉的 時段中，保持各自的積分器輸出為零；接著，該兩個積分 器的輸出供應給由運算放大器90、及電阻器91、92所93所 構成的加法放大器電路，以在該支路的輸出處傳遞該馬達 電流的一個忠實再現結果。 依照本發明，三相變頻器電橋的三個電橋支路可使用 和如第5圖或第6圖所示者類似的感測電路；或者，三個支 路中之二支路可使用這些感測電路，而第三支路的電流則 以另兩個支路電流之和予以重建；後者的配置將需要一個 差動變壓器或其他裝置，用以在接地故障電流是必需的者 本紙張尺度這用中國國家樣率（〇叫入4驗（2】〇乂297公着) "~ 7 -10- 42704 9 經濟部智慧財產局員工消費合作社印製 A7 —-----—.一 --------B7___________ 五、發明說明（8) 時’感測第三支路中的接地故障電流。 雖然本發明已經針對其特定實施例加以說明，但許多 其他的變化、修正和其他使用方式對熟於本項技術者將可 明顯看出；因此，較佳地，本發明不受本文所作待定揭露 内容所限制，而是只欲由後附的申請專利範圍予以限制。 元件標號對照 32…比流器 54···比流器 34…變頻器開關 56…比流器 34A…雙極電晶體 60，62…交流開關 34B…二極體 64，66…交流開關 35 ’ 36…二極體 68…電阻器 37…交流開關 70 ’ 72…變頻器開關 38…交流開關 74…線圈 39…電阻器 76…線圈 4卜··積分器 82，83···重設器 42…線圈 84…電容器 44…變頻器開關 86…電阻器 45…重設器 87…電阻器 46…電容器 88…運算放大器 47…運算放大器 卯…運算放大器 48…電阻器 91 ’ 92，93…電I5且器 50，52.··變頻器開關 本紙張尺度適用_國國家標準（CNS)A4規格（210 X 297公釐） ----*--- 1--I I 较- — ϊ!---訂 - - ------- (請先閱讀背面之注意事項再填寫本頁) -11 -The Rogowski coil can also be wound on a straight flexible non-magnetic structure; the entire coil is then removed 'and then looped around the primary conductor. A South Mass Integrator with a fast slew rate is also preferably used. Figures 5 and 6 show how the embodiment shown in Figures 3 and 4 respectively can be expanded to provide full motor current sensing; Figure 5 The figure shows an adaptation type using the sensing circuit of Fig. 3, where an AC current transformer is used; and the figure 6 shows an adaptation type using the sensing circuit of Fig. 4, which uses a Rogowski coil. As shown in Figure 5, a separate sensing circuit is used for each of the insulated gate bipolar transistor inverter switches 50 and 52 above and below the bridge branch; when the inverter switch 50 is on, the current An output signal proportional to the current flowing through the inverter switch 50 is passed to the signal generating resistor 68 through the primary winding of the current transformer 54 and its secondary winding; this signal is supplied to the upper insulated gate bipolar transistor When the PWM signal of the inverter switch 50 is turned off, it is cut off by the AC switches 64 and 66 and cannot reach the resistor 68. Similarly, when the lower insulated gate bipolar transistor inverter switch 52 is turned on, the current passes through the primary winding of the current transformer 56 and the current transformer 56 transmits an output signal via its secondary winding to the resistor 68 The signal is proportional to the current in the switch of the relevant inverter; the output of the wheel is supplied to the inverter below. The paper size applies to the Chinese National Standard (CNS) A4 specification {210X2S »7 mm) --------- ----- Install-^ ----- ^ Order ------- ^ --- (Please read the note on the back before filling this page) -9- 427049 A7 _ B7 V. Invention Explanation (7) When the pulse width modulation signal of the device switch 52 is in the off state, it is cut off by the AC switches 60 and 62 to reach the resistor 68; therefore, the outputs of the two sensing circuits are thus output on the branch The result is a faithful motor current that is composed to deliver. Employees of the Central Standards Bureau of the Ministry of Economic Affairs remove the seal of the cooperative ^^^ 1 ^^^ 1 ^^^ 1 ^^^ 1 I m-is — UK-* d Λ ",-* c Please read the notes on the back before (Fill in this page) The circuit shown in Figure 6 above uses separate ROg0wski coil sensing circuits above and below the bridge branch, each of the insulated gate bipolar transistor inverter switches 70 and 72 ; Here, the R0g0wski coil 74 passes an output voltage that is proportional to the di / dt of the primary current supplied by the inverter switch 70 above and the Rogowski coil 76 passes a similar signal to the inverter switch 72 below Output voltage; an integrator composed of operational amplifier 88, capacitor 84 and resistor 86 is used to transmit a signal representing the switching current of the upper frequency converter; and an integrator composed of operational amplifier 89, capacitor 85 and resistor 87 transmits a representative Corresponding signal of the lower inverter switching current; advantageously, the resetters 82 and 83 maintain their respective integrals during the periods when the individual pulse width modulation signals supplied to each of the upper and lower inverter switches 70 and 72 are turned off Output Zero; then, the outputs of the two integrators are supplied to an adder amplifier circuit composed of the operational amplifier 90 and the resistors 91 and 92 to pass a faithful reproduction of the motor current at the output of the branch . According to the present invention, three bridge branches of a three-phase inverter bridge may use a sensing circuit similar to that shown in FIG. 5 or FIG. 6; or, two of the three branches may be used. These sensing circuits, and the current of the third branch is reconstructed by the sum of the currents of the other two branches; the latter configuration will require a differential transformer or other device to be used if ground fault current is required. The scale is based on China's national sample rate (〇 called into 4 tests (2) 〇297297) " ~ 7 -10- 42704 9 A7 printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs ---------. A -------- B7___________ V. Description of the invention (8) 'Senses the ground fault current in the third branch. Although the present invention has been described in terms of its specific embodiment, many other changes and modifications And other ways of use will be apparent to those skilled in the art; therefore, preferably, the present invention is not limited by the pending disclosures made herein, but is only intended to be limited by the scope of the attached patent application. Reference number 32 ... Flow ratio 54 ... Flow ratio 34 ... Inverter switch 56 ... Current converter 34A ... Bipolar transistor 60, 62 ... AC switch 34B ... Diode 64, 66 ... AC switch 35 '36 ... Diode 68 ... Resistor 37 ... AC switch 70' 72 ... Inverter switch 38 ... AC switch 74 ... coil 39 ... resistor 76 ... coil 4 ... integrator 82, 83 ... resetter 42 ... coil 84 ... capacitor 44 ... inverter switch 86 ... resistor 45 ... heavy Set 87 ... resistor 46 ... capacitor 88 ... op amp 47 ... op amp 卯 ... op amp 48 ... resistor 91 '92,93 ... electric I5 and rectifier 50, 52. ·· Inverter switch Applicable to this paper size_ 国National Standard (CNS) A4 Specification (210 X 297 mm) ---- * --- 1--II Compare--ϊ! --- Order--------- (Please read the first Please fill in this page again for attention) -11-