為輕型電動汽車設計一款電機調(diào)速控制器外文翻譯

1、<p>　　2500英文單詞，1.3萬英文字符，中文3800字</p><p>　　文獻出處：Carroll, Klug B, Dimitrov D, et al. Design of a motor speed controller for a lightweight electric vehicle[J]. 1999:559-562.</p><p>　　畢業(yè)設計（論文）外文

2、文獻翻譯</p><p><b>　　原文：</b></p><p>　　DESIGN OF A MOTOR SPEED CONTROLLER FOR A LIGHTWEIGHT</p><p>　　ELECTRIC VEHICLE</p><p>　　Ben Carroll, Dennis Klug, Lina Dim

3、itrov, Stacy Marmara, Rae Montemayor,</p><p>　　Aric Shaffer, Paul Shaub, Edmund Tse, and Mark Thompson</p><p>　　Department of Electrical and Computer Engineering</p><p>　　Kettering

4、University</p><p><b>　　Abstract</b></p><p>　　The design of a dc motor speed controller for application in a lightweight electric vehicle is discussed .The focus is on the design of

5、the power electronics stage and the microcontroller-based digital control system to provide safe and reliable operation.</p><p>　　1. INTRODUCTION</p><p>　　Each engineering curriculum at Ketterin

6、g University includes a capstone design experience. These courses emphasize design fundamentals and teamwork and culminate in the design of a significant device or system, usually of a multidisciplinary nature. This pape

7、r describes a capstone design project assigned to a team of eight electrical and computer engineering students at Kettering University in the fall term of 1998. The project consisted of the design, construction, and demo

8、nstration of a pulse </p><p>　　The basic specifications at the outset of the project were: </p><p>　　* The controller should operate over a range of voltages from 24 V to 48 V. </p><p

9、>　　* The controller should be able to handle a current load of at least 100 A rms. </p><p>　　* PWM operation should be in the inaudible frequency range (recommended 20 kHz). </p><p>　　* Under

10、-voltage, over-current, and temperature protection must be employed. </p><p>　　* Budgeted expenditures must not exceed $500.00.</p><p>　　The design team was organized into groups of engineering

11、specialists with each group assuming primary responsibility for the design of a particular segment of the overall system. For this project, the specialist areas were defined as 1) power electronics design, 2) microcontro

12、ller design, 3) system simulation, and 4) sensor and interface design. The power electronics group selected the basic switching circuit topology along with the main switching components, gate drivers, and analog protecti

13、on </p><p>　　In addition to the controller design, the team designed and fabricated a go-kart chassis with electric drive train to serve as a test vehicle for the controller. An Advanced DC motor (model 140-

14、01-4005) rated at 48 V and 350 A (intermittent) was chain coupled to a solid axle via sprockets with a 4: 1 reduction ratio. The battery pack was nominally 48 V consisting of six, 8 V Delco deep cycle lead acid batteries

15、. The vehicle curb weight was 500 lbs.</p><p>　　2. DISCUSSION</p><p>　　A. Power Electronics Design </p><p>　　The motor controller utilizes a buck converter (see Figure 1) operating

16、 a series wound DC motor in the continuous current mode at power levels up to 28.8 kW from a 48 V battery pack. The low voltage and high power level results in intermittent battery currents up to 600 A and motor circul

17、ating currents in excess of 1000 A. At this level of current, the layout and protection of the circuit is paramount to the converters reliable operation. The converter is divided into four components: the powe</p>

18、<p>　　1. Power Semiconductors </p><p>　　A MOSFET switch was selected since they offer the lowest conduction losses in the 50 V range and are relatively easy to control compared to insulated gate bipola

19、r transistors (IGBTs). Power modules are available that can switch the required current with a single device but their costs are prohibitive. Motor controllers for small electric vehicles such as golf carts use many smal

20、l package MOSFETS in parallel since their small die size and popularity make them inexpensive. The IXYS IXFN 200 NO7 po</p><p>　　The free-wheeling diode of a buck converter of this size can be a source of si

21、gnificant losses. Two major factors addressed in this design were the forward voltage drop and thereverse recovery time of the free-wheeling diode. Schottky diodes perform significantly better than PN junction diodes in

22、these two regards, but until recently were not available at the required voltage level. A dual Schottky device in a SOT-227 package (IXYS D552X6101A) was chosen for the free-wheeling diode. The design r</p><p&

23、gt;　　2. Microprocessor Isolation / Gate Driver </p><p>　　A high speed opto-coupler was used to isolate the microprocessor from the gate drive circuitry. The opto- coupler fed each MOSFET gate driv

24、er circuit. Using an individual gate driver for each MOSFET allowed the elimination of the gate drive resistor required to squelch parasitic oscillation. The turn-on and turn-off speeds could then be controlled via the

25、gate supply voltage or by changing to gate drivers of different current ratings. The gate driver circui was designed so that if an</p><p>　　3. Heat Sink </p><p>　　The heat sink was custom design

26、ed and cast using the lost foam method. An H-shaped design provided electromagnetic and physical isolation of the sensitive analog and digital circuits from the power section. The layout of the heat sink design is illust

27、rated in the photograph of Figure 3. In the event of device failure, the shrapnel and soot would be contained within the power side. Process capabilities limited the fin density on the sink to less than the calculation

28、s suggested. Experiments dete</p><p>　　4. Filter Capacitors </p><p>　　The filter capacitors snub the switching transients to prevent damage to the devices from inductive flyback. The energy stor

29、ed in the parasitic inductance was calculated for the wiring, batteries, and bussbars. This energy was used to calculate the filter capacitors minimum required value. To transfer this energy fast enough to snub the trans

30、ients requires that the capacitors have low parasitic resistance (also limiting dissipation) and inductance. A capacitor bank consisting of high ripple cur</p><p>　　B. Controller / Software Design </p>

31、;<p>　　The Motorola 68HC12 microcontroller provides the intelligence necessary for safe and reliable operation of the electric motor controller. There were two primary objectives in the design of this controller.

32、The controller was to generate a PWM signal to switch the power electronics and thus control the voltage across the motor. The duty cycle of the PWM output was to be controlled by the position of the foot throttle pedal.

33、 Safety was also a primary concern. Several algorithms offer extensive cur</p><p>　　Many of the input signals were given threshold levels, at which certain events were triggered. In order to avoid fluctuati

34、ons near the threshold levels due to noise or quantization errors, hysteresis curves were implemented on all such thresholds.</p><p>　　Due to time constraints, the software design was kept as simplistic as p

35、ossible yet the software was still designed to be effective, responsive, programmable and modular. In order to maintain a stable system it was important to consider the approximate feedback time of the system. As noted e

36、arlier, the 68HC12’s interrupt system was used to achieve an optimal rate of response. The program was divided into smaller units, each one monitoring a specific input or set of inputs as shown in the block d</p>

37、<p>　　a. Throttle position sensor (TPS)- Controls acceleration and deceleration </p><p>　　b. Thermal protection sensor- Monitors the temperature of the motor housing and the controller power electronics

38、 </p><p>　　c. Battery under-voltage sensor- Monitors the total battery voltage </p><p>　　In addition to these input sensor routines, a display routine was added for the digital readouts on the d

39、isplay box as illustrated in Figure 4.</p><p>　　1. Current Overdraw Protection </p><p>　　Current overdraw protection is vital to the lifetime of the power electronics components and the motor i

40、tself. Response times to current spikes or surges are critical in preventing damage. The response time of the microcontroller is limited by its processing speed- 8 MHz for the Motorola 68HC12. A separate analog circuit

41、was designed to detect extreme instantaneous current spikes. </p><p>　　This circuit shut down the system and required a manual reset to resume operation. In most cases this circuit only faulted during tire

42、slippage of the cart. The microcontroller based protection offered average current protection over approximately three time constants.</p><p>　　When the current levels rose above the desired thresholds, the

43、duty cycle of the PWM wave was reduced by about 10% and operation resumed. If the current did not return to an acceptable level, additional reductions of 5% were accumulated. This routine operated constantly in the backg

44、round and was periodically interrupted to service the other routines microcontroller based protection offered average current protection over approximately three time constants. When the current levels rose above the <

45、;/p><p>　　2. Throttle Position Sensor </p><p>　　This algorithm read the signal from the foot throttle and adjusted the duty cycle of the PWM output accordingly. This routine used programmable line

46、ar acceleration and deceleration ramps to adjust the duty cycle. The foot throttle potentiometer was configured to provide 0-4.8 V output, with 0 V corresponding to stop and 4.8 V corresponding to full throttle. As a sa

47、fety feature, this routine shut down the output PWM wave if the voltage of the foot throttle potentiometer inadvertently exceeded 4.</p><p>　　3. Thermal Protection </p><p>　　A single thermal pr

48、otection algorithm read both the motor housing temperature and the controller’s power electronics temperature. If one or more of these temperatures exceeded programmable operating points, the output PWM duty cycle was re

49、stricted. Once the temperature of the hot component returned to within the normal operating range, the restriction was removed. </p><p>　　4. Battery Under-Voltage Protection </p><p>　　The focus

50、 of this algorithm was to shutdown the system in the event that the supply battery voltage became too low. It also was recognized that the driver may want the ability to “l(fā)imp” home rather than be stranded where the batt

51、eries ran out. As a result, three programmable thresholds were used to achieve a tri-level hysteresis. With fully charged batteries, the controller would continue to operate normally until the middle threshold was reache

52、d. At this point, the output PWM wave was restricte</p><p>　　5. Display Box Routine </p><p>　　As a late addition to the controller, this algorithm was introduced to switch between current readin

53、gs and percent duty cycle readings (the switch was located on the display box) and provided the appropriate output signals to the display box. These outputs were used to control three 7- segment displays for the digital

54、 readouts. Indicator LEDs were also used to show restricted conditions in the controller due to temperature or excessive currents. Due to the fact that this routine ran much less f</p><p>　　ACKNOWLEDGMENTS&l

55、t;/p><p>　　We would like to thank Jeff Wolak and Paul Schweitzer for construction of the go-kart test platform and Kettering University Motorsports for the use of their tools and facilities. Also, thanks to Jer

56、ry Kozlowski in the ECE Crib for his assistance and to IXYS Corporation for donation of parts. Benjamin L. Carroll received the Bachelor of Science degrees in electrical and mechanical engineering from Kettering Universi

57、ty in 1999. He is a member of Eta Kappa Nu. He joined Crown International in 199</p><p><b>　　譯文：</b></p><p>　　為輕型電動汽車設計一款電機調(diào)速控制器</p><p>　　摘要：本文主要討論了應用在輕型電動汽車的直流電機速度控制器的

58、設計。討論的焦點在電力電子平臺以及基于微型控制器的數(shù)字控制系統(tǒng)的設計上，以提供安全、可靠的運行。</p><p><b>　　一 簡介：</b></p><p>　　凱特林大學的每個工程學課程都包含一次頂峰的設計經(jīng)歷。這些課程強調(diào)設計基礎和團體合作，以設計出一個具體重要意義的設備或體系（通常是多學科性質(zhì)）成為制高點.本文主要介紹了1998年第一學期凱特林大學的8位電

59、子和計算機工程學的學生組成的一個團體所設計的一個頂峰設計項目。該項目包括了應用于輕型電動汽車的脈沖寬度調(diào)制直流電機速度控制器的設計、建立和示范的過程。</p><p>　　在項目的最初主要技術規(guī)范如下：</p><p>　　a. 控制器運行的電壓為24到28伏之間。</p><p>　　b. 控制器能處理電流的有效值為100A以上的負載。</p>&l

60、t;p>　　c. 脈沖寬度調(diào)制應在聽頻范圍之外工作（建議20千赫茲）。</p><p>　　d. 需設置欠壓、過流和溫度保護。</p><p>　　e. 預算開支不超過500美元。</p><p>　　這個設計團體分成若干個具有專業(yè)技術的小分隊，每個分隊負責各自相關部分的設計。</p><p>　　在這個項目中，各個專業(yè)小組分別定義為：

61、電源電子設計、微控制器設計、系統(tǒng)仿真、傳感器和接口設置。電源電子設計組選擇基礎的開關電路和總開關元件的布局，柵極驅(qū)動器，和模擬保護電路。微控制器組主要負責開發(fā)和設計數(shù)字控制運算法的任務以符合項目的技術條件。仿真組負責開發(fā)系統(tǒng)組件的模型并利用SABER程序來模擬電力電子和保護電路。傳感器組負責在保護電路里加一個電流傳感器電路，兩個溫度傳感器電路（監(jiān)視電機外殼的溫度和散熱片的溫度），和為微控制器提供所需速度信號的節(jié)氣門位置傳感器。團隊的隊長

62、協(xié)調(diào)各個小組之間的工作并加快各個子系統(tǒng)組合成整個體系的速度。</p><p>　　除了控制器的設計，該團隊還設計并組裝了一個有電力驅(qū)動機構(gòu)的賽車底座作為控制器的測試車。一種先進的直流電機48V/ 350A（型號140-01-4005）通過一個4：</p><p>　　1減速比的鏈齒與車軸鏈接。48伏的電池組包括6個8伏的德爾科深循環(huán)鉛酸電池，這輛車整車質(zhì)量為500磅。</p>

63、<p><b>　　二 討論 </b></p><p><b>　　1 電源電子設計</b></p><p>　　在48伏的電池組下，電機控制器采用了降壓變換器（如圖1），使一系列的直流電機能在功率高達28.8千瓦的連續(xù)的電流模式中運行。低電壓和高功率導致間斷性電池電流上升到600A，電機的循環(huán)電流超過1000A。在這樣的電流中，電

64、路的布局和保護對轉(zhuǎn)換器的可靠操作顯得尤為重要。轉(zhuǎn)換器可分為以下四個部件：功率半導體、微處理器、門驅(qū)動電路、散熱器、濾波電容。 </p><p>　　圖1. 降壓變換電路圖</p><p><b>　?。?）功率半導體 </b></p><p>　　我們選擇金屬氧

65、化物半導體場效應晶體管（MOSFET）作為開關元件，因為它在50伏的范圍內(nèi)可以將導通損耗減到最低，而且與絕緣柵雙極晶體管（IGBTs）相比，這個更容易控制。有一種電源模板，可以用單個設備開啟我們所需的電流，但是它所需的價格太高。小型的電動汽車如高爾夫車上的電機控制器都采用串聯(lián)的MOSFET，因為這一類晶體管的小尺寸芯片和其通用性能它的價格不會很高。愛塞斯200的7號電源MOSFET解決了這兩個極端產(chǎn)生的問題。為了提高安全系數(shù)，這四個部件

66、都是并聯(lián)上去的。</p><p>　　這種型號的降壓變換器中的續(xù)流二極管可能會產(chǎn)生巨大的損耗。這主要有兩個原因：二極管正向壓降和續(xù)流二極管的反向恢復時間。在這兩個方面肖特基二極管比PN結(jié)二極管占有優(yōu)勢。但這個目前不能在所需的電壓中適用。續(xù)流二極管選用了STO-227封裝（IXYS制造D552X6101A）中的雙肖特基設計。為使設計有一定的安全性，必須適用這樣的四種裝置。大家想到了用同步整流器代替二極管，但是經(jīng)調(diào)查

67、發(fā)現(xiàn)并沒有減少其損耗。</p><p>　?。?）微處理器隔離/門驅(qū)動器</p><p>　　一種高速的光耦合器可以用來隔離微處理器和門驅(qū)動電路。這種光耦隔離器適合每個MOSFET的柵極驅(qū)動電路，每個MOSFET適用各自的門驅(qū)動器可以消除門驅(qū)動電阻，因而控制寄生震蕩。通過控制柵極電源電壓或者更改不同額定電流的柵極驅(qū)動器可以控制MOSFET導通和關斷的速度。如果其中任何部件發(fā)生意外，門驅(qū)動電

68、路可以迫使MOSFET關斷，這就是設計門驅(qū)動電路的原因。</p><p>　　圖2所示的是在150A電池電流下MOSFET典型導通和關斷時的電壓波形。關斷電壓波形時從10%到90%的上升時間是409納秒，開啟電壓波形時的下降時間是387納秒。這些開關的時間足夠為轉(zhuǎn)換電路提供合理的熱性能，而且不用改變門驅(qū)動電路來減少開啟和關斷的時間。濾波電容器對于在關閉時少于10伏電壓時，其感應環(huán)不會有反應。這就在通過MOSFET

69、觀測到的峰值電壓和設備額定的最大雪崩電壓兩者之間提供了10伏的安全度。</p><p>　　圖2.1 MOSFET導通的波形</p><p>　　圖2.2 MOSFET關斷的波形</p><p><b>　?。?）散熱片</b></p><p>　　這個散熱片是用消失模的方法進行定制設計并鑄造的。一個個H形的設計提供了從

70、電源部分電磁和物理敏感的模擬和數(shù)字電路的隔離。散熱片的布局如圖3所示。一旦設備失效，其爆破碎片和煙灰都會保留在電源附近。工序能力把散熱器的管密度控制在少于建議的計算結(jié)果。實驗發(fā)現(xiàn)電機的溫度是一個限制性因素，高于控制器散熱片的溫度就超出了這個極限。</p><p>　　圖3.控制器安裝在散熱片上</p><p><b>　?。?）濾波電容器</b></p>

71、<p>　　該過濾器的開關電容瞬態(tài)不會變化，以防止損壞感應反激式的設備。儲存在寄生電感的能量是為適合電線，電池和總線而設計的。這種能源被用來計算濾波電容所需的最低值。該電容器瞬態(tài)要求具有低寄生電阻（也限制功耗）和電感，從而能足夠快速的轉(zhuǎn)移能量。安裝在雙面印刷電路板的電容器組由高紋波電流電解電容器和金屬化聚酯電容器組成。電源和地平面被用來限制微小的自感，并作為額外的寄生電容。</p><p>　　2

72、控制器/軟件設計</p><p>　　摩托羅拉68HC12微控制器為安全可靠的電機控制器操作提供了所必需的信息。</p><p>　　控制器設計主要有兩個功能：由控制器產(chǎn)生PWM信號切換電源電子，從而控制了整個電機電壓；由足油門踏板的位置控制PWM的輸出占空比。安全也是一個主要關注的問題，幾種算法提供了大量的電流保護，電機和控制器的熱保護，另外還有電池欠壓保護。</p>&l

73、t;p>　　基于微控制器的數(shù)字控制系統(tǒng)選擇的靈活性一定程度上是由于現(xiàn)有的專業(yè)知識決定的。隨著摩托羅拉68HC12的使用，已有相當大的能力去調(diào)整性能。一旦控制器啟動和運行，很容易用數(shù)字顯示并讀出電流或占空比。軟件方面大量應用了68HC12的中斷系統(tǒng)，從而提供靈活的時間安排和建立一個優(yōu)先計劃，來應對最重要的信號作為第一個信號（即過流信號）。</p><p>　　許多由某些事件觸發(fā)的輸入信號都設置了門限值。所有這

74、些門限設置滯后曲線是為了避免門限值附近由噪聲或量化誤差的波動。 在軟件設計仍然有效、反應靈敏、可編程和模塊化的前提下，應盡可能簡潔來減少時間。為了保持一個穩(wěn)定的系統(tǒng)，重要的是要考慮系統(tǒng)的近似反饋時間。如前所述，該68HC12的中斷系統(tǒng)被用來達到最佳的反應速度。該程序分為較小的模塊，每一個模塊監(jiān)控一個特定的輸入或作為輸入設置顯示在圖4框圖。每個輸入通常被分配一個與各自的傳感器的讀數(shù)所要求的頻率相關的優(yōu)先級。這些優(yōu)先級根據(jù)輸入信號的

75、變化率和重要性來設置。過流傳感器設置為最高優(yōu)先級。</p><p>　　余下的傳感器每個排列如下：</p><p>　　a. 節(jié)氣門位置傳感器（TPS）——控制電機加速和減速b. 熱保護傳感器——監(jiān)視電機外殼和電源電子控制器的溫度c. 電池欠電壓傳感器——監(jiān)視總電池電壓</p><p><b>　　圖4. 程序布局</b></p

76、><p>　　除了這些常用輸入傳感器，顯示器經(jīng)常加入如圖4所示的顯示框數(shù)字讀出器。</p><p><b>　?。?）過流保護</b></p><p>　　過流保護對電源電子元件的壽命和電機本身是至關重要的。響應時間對于預防浪涌電流尖峰的損壞很有用。摩托羅拉68HC12微控制器的響應時間受到其處理速度—— 8兆赫的限制。使用單獨的模擬電路設計，以偵

77、查極端的瞬時電流峰值。 當電路系統(tǒng)關閉時，需要手動復位才能恢復運作。大多數(shù)只在車輪胎的滑移斷裂的情況下該電路才會出現(xiàn)故障。基于微控制器的保護提供了大約超過3倍的平均電流保護。 當電流值上升高于預期的門限值，PWM波形的占空比就以10％左右減少，從而恢復正常運行。如果電流沒有返回到可接受的值，就以5％的額外削減進行積累。在后臺不斷操作此程序，并定期打斷其他服務程序。</p><p>　?。?）節(jié)氣門

78、位置傳感器</p><p>　　該算法從讀足油門信號并且相應的調(diào)整了PWM輸出占空比。這個程序使用的可編程線性加速和減速斜坡來調(diào)整占空比。足油門電位器被配置為0~4.8 V的輸出，即0 V相當于停止和4.8 V相當于全油門。作為一個安全特性，如果足油門電位器的電壓超過4.9V，這個程序會關閉輸出PWM波形。這種保護，不會因線路故障、短路或電位打破啟用，因此可以消除控制器停留在全油門的機會。</p>

79、<p><b>　?。?）熱保護</b></p><p>　　一個單一的熱保護算法同時能讀出電機外殼溫度和控制器的電源電子溫度。如果一個或更多的這樣的溫度超過了已設計的工作點，那么輸出PWM占空比就會受到限制。一旦熱元件產(chǎn)生的溫度返回到正常工作范圍內(nèi)，限制被解除。</p><p><b>　　電池欠壓保護</b></p>

80、<p><b>　　（4）電池欠壓保護</b></p><p>　　該算法的重點是在事件電池電壓變得過低的時候能夠關閉系統(tǒng)。系統(tǒng)也認識到驅(qū)動程序可能需要“蹣跚”到家的能力，而不是電池用完被滯留。因此，用3個可編程閾值來實現(xiàn)三個等級滯后。對于充足電的電池，控制器會繼續(xù)運作直至到達中間的門限值。在這一點上，輸出PWM波就會被限制，讓司機可以跛行回家。當電池電壓接近耗盡的時候，如果驅(qū)動程

81、序繼續(xù)推動“跛行”車，控制器將切斷輸出PWM波形。</p><p><b>　?。?）顯示框程序</b></p><p>　　另外作為一個新的控制器，引入了電流讀數(shù)和百分比占空比讀數(shù)之間的切換算法（切換結(jié)果位于顯示框里），并提供相應的輸出信號的顯示框。這些輸出信號用于控制3個7段顯示器來顯示數(shù)字?？刂破鞯南拗茥l件（溫度或過流）由LED指示燈來提示。事實上，這個程序運行

82、的頻率遠遠小于過流保護的算法，過流指示燈LED并不總是作出準確的并直觀地顯示控制器的狀態(tài)。這說明了在實時數(shù)字控制系統(tǒng)的響應時間和精度之間非常典型的折衷。</p><p><b>　　三 致謝 </b></p><p>　　我們要感謝Jeff Wolak 和 Paul Schweitzer搭建卡丁車測試平臺和提供凱特林大學賽車運動所需的工具、設施。此外，還要感謝歐洲經(jīng)委

83、會Kozlowski的援助和IXYS制造公司的一些贊助。</p><p><b>　　附：</b></p><p>　　1999年，Benjamin L. Carroll獲得了凱特林大學電子和機械的工程科學學士學位。之后，他成為了Eta Kappa Nu的成員。在1995年，他以合作社的學生加入了國際檢察官，現(xiàn)在是在新產(chǎn)品開發(fā)的電氣工程師。他目前的工作是在開關電源和開