TWI814206B - Method of clamping output current of three-phase power converter - Google Patents
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本發明係有關一種功率轉換器之輸出電流的控制方法,尤指一種三相功率轉換器之輸出電流的箝位控制方法。 The present invention relates to a method for controlling the output current of a power converter, and in particular to a method for clamping the output current of a three-phase power converter.
圖1係為傳統馬達驅動器的系統架構圖,其中馬達900透過功率轉換器100的驅動對欲控制之負載進行控制,另可配合參見圖3。圖2係為傳統三相功率轉換器的電路圖。功率轉換器100由六個開關構成的三臂(各包含一上臂開關Su1,Sv1,Sw1與一下臂開關Su2,Sv2,Sw2)架構所組成,每相輸出接至一臂上、下臂開關的中心點,為一已知且廣泛應用於工業產品之電路架構。
FIG. 1 is a system architecture diagram of a traditional motor driver, in which the
在各種不同的工業應用上,常會使用到功率轉換器(power converter)100來進行電能的轉換,如圖3所示,設置於交流側與直流側之的功率轉換器100將電池200的電能轉換,且提供功率給負載300使用。在此,功率轉換器100連接電池200之處可稱為「直流側」,不同實際應用中可以為電池、太陽能板、電容...等等。而圖3中之負載側亦可稱為「交流側」,不同實際應用中可以為馬達、電網、工業產品...等等。
In various industrial applications, a
具體地,圖3為應用於功率轉換器100之脈波寬度調製(pulse-width modulation,PWM)系統架構圖,根據不同實際應用,功率轉換器100對應的控制器400設計的方式也會不同。例如當負載300是電壓源(voltage source)時,功率轉換器100常應用為主動式前級(active front end),此時控制器400就必須調
節交流側的功率因數(power factor)。若負載300為馬達時,功率轉換器100就必須設計控制各種不同類型的馬達。因此,隨著應用的場合不同,功率轉換器100對應的控制器400設計也不同,但目的皆為控制交流側的電壓,來達到控制的目的。因此,控制器400會產生對應的電壓命令Vref,用以希望控制的交流側輸出電壓。再者,透過脈波寬度調製技術500可以轉換(調製)電壓命令Vref以輸出開關訊號給功率轉換器100上的開關元件模組切換來輸出對應的電壓。由圖3所示,功率轉換器100的輸出電壓為脈波形式的電壓,理想上,如果系統沒有任何損失的情況下,此脈波電壓的平均值會為電壓命令Vref。
Specifically, FIG. 3 is an architecture diagram of a pulse-width modulation (PWM) system applied to the
大多數應用於傳統三相功率轉換器之脈波寬度調製技術為稱作向量空間脈波寬度調製技術(SVPWM)的開關切換方式,其方法係為將三相各相的電壓命令跟一載波ePWM比較。如圖4所示,當該相電壓命令Vref大於載波ePWM時,該臂的上開關導通,下開關則關閉。如圖5所示,若將三相電壓命令(vu*,vv*,vw*)一起與載波ePWM比較,則可以將三相各臂的開關整理出如圖5所示(當vu*>vv*>vw*時),若分析各種不同的電壓命令組合,並將其輸出電壓轉至d-q同步框,則可以整理成由電壓向量v0-v7組成的空間向量圖(Space vector diagram),如圖6所示。舉例來說v1(100)代表U相上臂開關導通,V和W相下臂開關導通,另外v0(000)和v7(111)所產生出來的輸出電壓皆為零,故稱作零向量,其餘v1-v6向量則稱為主動向量。此PWM方式已廣泛應用於各種功率轉換器產品上。 Most pulse width modulation technology used in traditional three-phase power converters is a switching method called vector space pulse width modulation (SVPWM). The method is to combine the voltage command of each phase of the three phases with a carrier ePWM compare. As shown in Figure 4, when the phase voltage command V ref is greater than the carrier ePWM, the upper switch of the arm is turned on and the lower switch is turned off. As shown in Figure 5, if the three-phase voltage commands (v u *, v v *, v w *) are compared with the carrier ePWM, the switches of each arm of the three phases can be sorted out as shown in Figure 5 (when v u *>v v *>v w *), if you analyze various voltage command combinations and transfer their output voltages to the dq synchronization box, they can be organized into a space vector diagram composed of voltage vectors v 0 -v 7 (Space vector diagram), as shown in Figure 6. For example, v 1 (100) means that the U-phase upper arm switch is turned on, and the V and W-phase lower arm switches are turned on. In addition, the output voltages generated by v 0 (000) and v 7 (111) are both zero, so they are called zero. vector, and the remaining v 1 -v 6 vectors are called active vectors. This PWM method has been widely used in various power converter products.
由圖6可以解釋SVPWM的基本概念:三相電壓vu*,vv*,vw*命令轉至同步框後為v*,轉框過程中會得到電壓命令v*跟q軸的角度θ,不同的θ角度使得v*落在圖6的任一個向量三角形內。此電壓命令在一個開關週期內將由組成該三角形的電壓向量來合成。此時的電壓命令v*落在由v1,v2,v0/v7組成的三角形區間,此時在一個PWM切換週期內,如圖5所示,輸出的電壓向量依序 為v7-v2-v1-v0-v1-v2-v7。因此,當電壓命令v*落在圖6任一個三角形區間內,是由該三角形內的兩個主動向量vx,vy和兩個零序向量v0,v7組合而成。表1為定義電壓區間與角度之關係。 The basic concept of SVPWM can be explained from Figure 6: the three-phase voltage v u *, v v *, v w * command is transferred to the synchronization frame to v*. During the frame transfer process, the angle θ between the voltage command v* and the q axis will be obtained. , different θ angles make v* fall within any vector triangle in Figure 6. This voltage command is synthesized by the voltage vectors that make up the triangle during a switching cycle. The voltage command v* at this time falls in the triangular interval composed of v 1 , v 2 , v 0 /v 7. At this time, during a PWM switching cycle, as shown in Figure 5, the output voltage vector is v 7 in sequence -v 2 -v 1 -v 0 -v 1 -v 2 -v 7 . Therefore, when the voltage command v* falls within any triangle interval in Figure 6, it is composed of two active vectors v x , v y and two zero sequence vectors v 0 , v 7 within the triangle. Table 1 defines the relationship between voltage range and angle.
然而,為了避免過電流損壞功率轉換器的元件,通常在馬達驅動器系統中,都會設計一套過電流的保護機制。為此,如何設計出一種功率轉換器之輸出電流的控制方法,尤指一種三相功率轉換器之輸出電流的箝位控制方法,解決現有技術所存在的問題與技術瓶頸,乃為本案發明人所研究的重要課題。 However, in order to prevent overcurrent from damaging the components of the power converter, an overcurrent protection mechanism is usually designed in the motor driver system. To this end, how to design a control method for the output current of a power converter, especially a clamp control method for the output current of a three-phase power converter, to solve the problems and technical bottlenecks existing in the existing technology, is the inventor of this case. important topics studied.
本發明之目的在於提供一種功率轉換器之輸出電流的控制方法,解決現有技術之問題。 The purpose of the present invention is to provide a method for controlling the output current of a power converter to solve the problems of the prior art.
為達成前揭目的,本發明所提出的功率轉換器之輸出電流的控制方法,其中三相功率轉換器包含三組開關橋臂,且每組開關橋臂具有串聯的上開關與下開關,且提供三相輸出電壓命令。箝位控制方法包括:(a)判斷輸出電流大於第一電流閾值時,啟動電流箝位控制程序;(b)比較載波訊號與三相輸出電壓 命令,且在載波訊號為上升區間,以第一零向量控制下開關導通,且在載波訊號為下降區間,以第二零向量控制上開關導通;以及(c)判斷輸出電流大於第二電流閾值時,啟動過電流保護程序,其中第二電流閾值大於第一電流閾值。 In order to achieve the aforementioned purpose, the present invention proposes a method for controlling the output current of a power converter, in which the three-phase power converter includes three sets of switch bridge arms, and each set of switch bridge arms has an upper switch and a lower switch connected in series, and Provides three-phase output voltage commands. The clamping control method includes: (a) when it is determined that the output current is greater than the first current threshold, starting the current clamping control program; (b) comparing the carrier signal with the three-phase output voltage command, and when the carrier signal is in the rising interval, the switch is turned on under the control of the first zero vector, and when the carrier signal is in the falling interval, the upper switch is turned on under the control of the second zero vector; and (c) determine that the output current is greater than the second current threshold When , the overcurrent protection program is started, in which the second current threshold is greater than the first current threshold.
在一實施例中,在步驟(b),在載波訊號到達波峰值時,以第一零向量控制下開關導通;在載波訊號到達波谷值時,以第二零向量控制上開關導通。 In one embodiment, in step (b), when the carrier signal reaches the peak value, the first zero vector is used to control the lower switch to turn on; when the carrier signal reaches the trough value, the second zero vector is used to control the upper switch to turn on.
在一實施例中,在步驟(c),過電流保護程序係控制三組開關橋臂的所有上開關與下開關關斷。 In one embodiment, in step (c), the overcurrent protection program controls all upper switches and lower switches of the three groups of switch bridge arms to turn off.
在一實施例中,執行該電流箝位控制程序時,該第一零向量與該第二零向量之間存在兩個相異的主動向量。 In one embodiment, when the current clamp control procedure is executed, there are two different active vectors between the first zero vector and the second zero vector.
在一實施例中,第一零向量係為用以控制三組開關橋臂的所有下開關皆導通的向量;第二零向量係為用以控制三組開關橋臂的所有上開關皆導通的向量。 In one embodiment, the first zero vector is a vector used to control all the lower switches of the three sets of switch bridge arms to be turned on; the second zero vector is a vector used to control all the upper switches of the three sets of switch bridge arms to be turned on. vector.
在一實施例中,在載波訊號到達波峰值或波谷值時,中斷電流箝位控制程序。 In one embodiment, when the carrier signal reaches a peak value or a trough value, the current clamp control procedure is interrupted.
在一實施例中,當載波訊號為上升到波峰值時進行中斷電流箝位控制程序,第一零向量接續控制下開關導通;當載波訊號為下降到波谷值時進行中斷電流箝位控制程序,第二零向量接續控制上開關導通。 In one embodiment, when the carrier signal rises to the wave peak value, the interrupt current clamping control process is performed, and the switch is turned on under the first zero vector continuous control; when the carrier signal drops to the wave trough value, the interrupt current clamping control process is performed. The second zero vector continues to control the upper switch to be turned on.
在一實施例中,在步驟(b)與步驟(c)之間更包含:(d)判斷輸出電流大於第三電流閾值時,啟動第二電流箝位控制程序,其中第三電流閾值大於第一電流閾值且小於第二電流閾值。 In one embodiment, between step (b) and step (c), the method further includes: (d) when it is determined that the output current is greater than a third current threshold, initiating a second current clamp control procedure, wherein the third current threshold is greater than the third current threshold. A current threshold and less than the second current threshold.
在一實施例中,執行第二電流箝位控制程序係透過控制三組開關橋臂的上開關關斷與下開關關斷。 In one embodiment, the second current clamping control process is executed by controlling the upper switch to turn off and the lower switch to turn off of the three groups of switch bridge arms.
在一實施例中,三相功率轉換器輸出所連接的負載為發電機或操作於發電機模式下的馬達。 In one embodiment, the load connected to the output of the three-phase power converter is a generator or a motor operating in generator mode.
藉此,本發明所提出的功率轉換器之輸出電流的控制方法,使馬達可以大幅地降低振動、輸出電流的漣波明顯下降、避免輸出電流(能量)回灌至直流側電壓側以及降低切換損失。 In this way, the control method of the output current of the power converter proposed by the present invention can greatly reduce the vibration of the motor, significantly reduce the ripples of the output current, avoid the feedback of the output current (energy) to the DC side voltage side, and reduce the switching loss.
為了能更進一步瞭解本發明為達成預定目的所採取之技術、手段及功效,請參閱以下有關本發明之詳細說明與附圖,相信本發明之目的、特徵與特點,當可由此得一深入且具體之瞭解,然而所附圖式僅提供參考與說明用,並非用來對本發明加以限制者。 In order to further understand the technology, means and effects adopted by the present invention to achieve the intended purpose, please refer to the following detailed description and drawings of the present invention. It is believed that the purpose, features and characteristics of the present invention can be understood in depth and For specific understanding, however, the attached drawings are only for reference and illustration, and are not intended to limit the present invention.
100:功率轉換器 100:Power converter
200:電池 200:Battery
300:負載 300:Load
400:控制器 400:Controller
500:脈波寬度調製技術 500: Pulse width modulation technology
900:馬達 900: Motor
SCC:箝位電流訊號 S CC : Clamp current signal
SCC1:第一箝位電流訊號 S CC1 : first clamp current signal
SCC2:第二箝位電流訊號 S CC2 : Second clamp current signal
Vref:電壓命令 V ref : voltage command
ePWM:載波 ePWM: carrier wave
Su1,Sv1,Sw1:上臂開關 S u1 ,S v1 ,S w1 : upper arm switch
Su2,Sv2,Sw2:下臂開關 S u2 ,S v2 ,S w2 : lower arm switch
iu,iv,iw:輸出電流 i u ,i v ,i w : output current
vu*,vv*,vw*:三相電壓命令 v u *, v v *, v w *: three-phase voltage command
Vref_max,Vref_mid,Vref_min:三相輸出電壓命令 V ref_max , V ref_mid , V ref_min : three-phase output voltage command
vx,vy,v1~v6:主動向量 v x , v y , v 1 ~ v 6 : active vector
v0,v7:零向量 v 0 , v 7 : zero vector
S1~S2:步驟 S1~S2: steps
S11~S13:步驟 S11~S13: Steps
圖1:係為傳統馬達驅動器的系統架構圖。 Figure 1: System architecture diagram of a traditional motor driver.
圖2:係為傳統三相功率轉換器的電路圖。 Figure 2: Circuit diagram of a traditional three-phase power converter.
圖3:係為傳統應用於功率轉換器之脈波寬度調製的系統架構方塊圖。 Figure 3: It is a system architecture block diagram of pulse width modulation traditionally used in power converters.
圖4:係為傳統功率轉換器之PWM切換方式的示意波形圖。 Figure 4: It is a schematic waveform diagram of the PWM switching method of a traditional power converter.
圖5:係為傳統三相功率轉換器SVPWM切換方式的示意波形圖。 Figure 5: It is a schematic waveform diagram of the SVPWM switching method of a traditional three-phase power converter.
圖6:係為傳統SVPWM切換下之電壓向量組成的向量空間圖。 Figure 6: It is a vector space diagram composed of voltage vectors under traditional SVPWM switching.
圖7:係為應用於馬達驅動器之電流保護機制的示意圖。 Figure 7: It is a schematic diagram of the current protection mechanism applied to the motor driver.
圖8:係為電流箝位控制方法的示意圖。 Figure 8: A schematic diagram of the current clamp control method.
圖9:係為電流箝位控制三相功率轉換器的等效電路圖。 Figure 9: Equivalent circuit diagram of a current clamp controlled three-phase power converter.
圖10:係為控制功率轉換器的開關全部關閉之示意圖。 Figure 10: It is a schematic diagram of controlling all switches of the power converter to be closed.
圖11:係為本發明以零向量控制功率轉換器的開關之示意圖。 Figure 11 is a schematic diagram of the present invention using zero vector to control the switch of the power converter.
圖12A:係為功率轉換器切換至零向量的第一實施例之電路圖。 Figure 12A: is a circuit diagram of the first embodiment of the power converter switching to zero vector.
圖12B:係為功率轉換器切換至零向量的第二實施例之電路圖。 Figure 12B is a circuit diagram of a second embodiment of the power converter switching to zero vector.
圖13:係為本發明以零向量控制功率轉換器的開關之第一實施例的具體示意圖。 Figure 13 is a specific schematic diagram of the first embodiment of the present invention in which the switch of the power converter is controlled with zero vector.
圖14:係為本發明以零向量控制功率轉換器的開關之等效電路圖。 Figure 14 is an equivalent circuit diagram of the present invention using zero vector to control the switch of the power converter.
圖15:係為本發明以零向量控制功率轉換器的開關之第二實施例的具體示意圖。 Figure 15 is a specific schematic diagram of the second embodiment of the present invention for controlling the switch of the power converter with zero vector.
圖16:係為本發明三相功率轉換器之輸出電流的箝位控制方法的流程圖。 Figure 16 is a flow chart of the output current clamping control method of the three-phase power converter of the present invention.
茲有關本發明之技術內容及詳細說明,配合圖式說明如下。 The technical content and detailed description of the present invention are as follows with reference to the drawings.
承前所述,為了避免過電流損壞功率轉換器的元件,通常在馬達驅動器系統中,都會設計一套過電流的保護機制,如圖7所示,其係為應用於馬達驅動器之電流保護機制的示意圖。系統之硬體或是韌體會回授輸出電流iu,iv,iw進行電流大小的判定。當任一相輸出電流iu,iv,iw瞬間大於上限電流值或超過過電流保護命令(即步驟S2的判斷為”是”)時,則功率轉換器100進入過電流保護,會將功率轉換器100所有的開關截止且系統停止運轉。
As mentioned above, in order to prevent overcurrent from damaging the components of the power converter, an overcurrent protection mechanism is usually designed in the motor driver system, as shown in Figure 7, which is the current protection mechanism applied to the motor driver. Schematic diagram. The system's hardware or firmware will feedback the output currents i u , i v , and i w to determine the current magnitude. When any phase output current i u , iv , i w is instantly greater than the upper limit current value or exceeds the over-current protection command (that is, the judgment in step S2 is "yes"), the
但有時候馬達負載只是發生急遽的暫態變化(例如瞬間加載、瞬間斷載或控制器失靈),當此急遽暫態變化過了之後,輸出電流iu,iv,iw就能穩定輸出。然而,此過電流保護機制就會限制功率轉換器100的操作彈性。因此,為了使增加馬達驅動器的操作範圍,保護機制會加入一個”箝位電流控制”,來協助功率轉換器100度過過電流的暫態。意即,當任一相輸出電流iu,iv,iw瞬間大於箝位電流值或超過箝位電流保護命令(即步驟S1的判斷為”是”)時,則功率轉換器100不會直接進入過電流保護,換言之,當輸出電流iu,iv,iw小於上限電流值或未超過
過電流保護命令(即步驟S2的判斷為”否”)時,會將功率轉換器100進入箝位電流控制,以抑制輸出電流iu,iv,iw的大小,而暫不會將功率轉換器100所有的開關截止且避免系統停止運轉,使得增加功率轉換器100的操作範圍,能夠度過某些暫態操作。然而,若當電流箝位控制仍無法抑制輸出電流iu,iv,iw大小時,系統還是會進入過電流保護。
But sometimes the motor load only undergoes a sudden transient change (such as instantaneous loading, instantaneous load loss or controller failure). After the sudden transient change has passed, the output current i u , i v , i w can be stably output. . However, this over-current protection mechanism limits the operating flexibility of the
電流箝位控制方法如圖8所示,圖中三相電壓命令(或稱三相輸出電壓命令)依最大值、中間值以及最小值依序為Vref_max,Vref_mid,Vref_min,分別與圖中三角波(載波)比較後產生PWM訊號。每個切換週期內,都由兩個主動向量vx,vy和零(序)向量v0,v7組合而成。配合參見圖7,當偵測系統任一相輸出電流iu,iv,iw超過箝位電流值時(即步驟S1的判斷為”是”),電流保護系統會產生箝位電流訊號(clamping current signal)SCC給控制器。當控制器接收到箝位電流訊號SCC,如圖8用箭頭標示的旗標訊號,會立即將所有的開關訊號截止(Gate off)。如圖10所示,第一個或第三個旗標訊號生效時,在主動向量vx時則立即進入Gate off狀態。若是在Gate off狀態時出現(第二個)旗標訊號,則仍持續維持Gate off狀態。 The current clamp control method is shown in Figure 8. In the figure, the three-phase voltage commands (or three-phase output voltage commands) are V ref_max , V ref_mid , and V ref_min in order of the maximum value, the middle value, and the minimum value, respectively. The triangular wave (carrier wave) is compared to generate a PWM signal. Each switching cycle is composed of two active vectors v x , v y and zero (sequence) vectors v 0 , v 7 . Referring to Figure 7, when the output current i u , iv , and i w of any phase of the detection system exceeds the clamping current value (that is, the judgment of step S1 is "yes"), the current protection system will generate a clamping current signal ( clamping current signal)S CC to the controller. When the controller receives the clamping current signal S CC , such as the flag signal marked with an arrow in Figure 8, it will immediately turn off all switching signals (Gate off). As shown in Figure 10, when the first or third flag signal takes effect, it immediately enters the Gate off state at the active vector v x . If the (second) flag signal occurs during the Gate off state, the Gate off state will continue to be maintained.
圖8中所示的SINTR係為控制器的中斷訊號(interrupt signal),通常會在一個切換週期的波峰或波谷時產生,用以重置(reset)箝位電流訊號SCC的旗標訊號。當控制器接收到中斷訊號SINTR後,會再對輸出電流大小做一次判定,若判定電流大小仍大於箝位電流值,則持續維持箝位電流控制,以持續對輸出電流進行抑制。反之,若判定電流大小已經小於箝位電流值(因為透過箝位電流控制的抑制),則透過在波峰或波谷時的中斷操作,使得切回PWM輸出的正常運作,此時的等效電路如圖9所示。若當下電流流向為iu<0,iv>0,iw>0,則依據當下電流的流向導通對應的背接二極體(而非上、下開關)進行放電,以達到對輸出電流的箝位抑制,然而,馬達側的線對線跨壓為直流側電壓Vdc變動較大,例如 由+Vdc跳動至-Vdc或者由-Vdc跳動至+Vdc,如此會造成輸出側電流有較大的電流漣波,使得機械馬達有較大的振動。 S INTR shown in Figure 8 is the interrupt signal of the controller. It is usually generated at the peak or trough of a switching cycle and is used to reset the flag signal of the clamping current signal S CC . . When the controller receives the interrupt signal S INTR , it will make another judgment on the output current. If it is judged that the current is still greater than the clamping current value, it will continue to maintain the clamping current control to continue to suppress the output current. On the other hand, if it is determined that the current size is less than the clamping current value (because of the suppression by the clamping current control), the interrupt operation at the peak or valley will switch back to the normal operation of the PWM output. The equivalent circuit at this time is as follows: As shown in Figure 9. If the current flow direction is i u <0, i v >0, i w >0, then the corresponding back-connected diode (rather than the upper and lower switches) is discharged according to the current flow to achieve the output current. However, the line-to-line cross-voltage on the motor side causes the DC side voltage V dc to fluctuate greatly, such as jumping from +V dc to -V dc or from -V dc to +V dc , which will cause the output The side current has large current ripples, causing the mechanical motor to vibrate greatly.
再者,透過將所有開關關斷的方式來達成輸出電流抑制的方式另外會發生的現象為輸出電流(能量)回灌至直流側電壓側,如此將造成直流側電壓升高,則會啟動過電壓保護。 Furthermore, by turning off all switches to achieve output current suppression, another phenomenon that will occur is that the output current (energy) is fed back to the DC side voltage side. This will cause the DC side voltage to increase, which will trigger the overcurrent. voltage protection.
請參見圖16所示,其係為本發明三相功率轉換器之輸出電流的箝位控制方法的流程圖。三相功率轉換器包含三組開關橋臂,且每組開關橋臂具有串聯的上開關與下開關,且提供三相輸出電壓命令。所述箝位控制方法的步驟詳述如下。 Please refer to FIG. 16 , which is a flow chart of the output current clamping control method of the three-phase power converter of the present invention. The three-phase power converter includes three sets of switch arms, and each set of switch arms has an upper switch and a lower switch connected in series and provides three-phase output voltage commands. The steps of the clamp control method are detailed as follows.
首先,判斷輸出電流大於第一電流閾值時,啟動電流箝位控制程序(S11)。如前所述,箝位電流控制方法對於馬達輸出側跨壓較大,容易使得馬達電流漣波增加,造成馬達振動。因此,本發明提出的三相功率轉換器之輸出電流的箝位控制方法,不使用將功率轉換器的開關全部關閉之方式(如圖10所示),而是將功率轉換器100切換至零向量(如圖11所示)。具體地,如圖11所示,當控制器接收到箝位電流訊號SCC的第一個旗標訊號時,則以第一零向量v0控制三相橋臂的上、下開關,意即,控制所有下開關導通且控制所有上開關關斷,而非採用對所有的上、下開關皆關斷控制。同理,當控制器接收到箝位電流訊號SCC的第二個旗標訊號時,則以第二零向量v7控制所有上開關導通且控制所有下開關關斷。值得一提,配合參見圖13,當載波訊號為上升到波峰值時進行中斷電流箝位控制程序,第一零向量v0接續控制下開關導通,並且當載波訊號為下降到波谷值時進行中斷電流箝位控制程序,第二零向量v7接續控制上開關導通,如此可降低切換損失。
First, when it is determined that the output current is greater than the first current threshold, the current clamp control program is started (S11). As mentioned before, the clamping current control method has a large cross-voltage on the output side of the motor, which can easily increase the motor current ripple and cause the motor to vibrate. Therefore, the clamp control method of the output current of the three-phase power converter proposed by the present invention does not use the method of closing all the switches of the power converter (as shown in Figure 10), but switches the
此時,等效電路如圖12A與圖12B所示,其中圖12A為功率轉換器100切換至零向量v7,而圖12B為功率轉換器100切換至零向量v0。由於
電流在功率轉換器100內部流動,因此可達成輸出電流的抑制,並且可避免輸出電流(能量)回灌至直流側電壓側。此時,馬達900的輸出電壓在零向量切換時線對線跨壓為零,大大降低了輸出電流的漣波,使馬達900即使在箝位電流控制操作下,可以大幅地降低振動。
At this time, the equivalent circuit is as shown in FIG. 12A and FIG. 12B , where FIG. 12A shows the
然後,比較載波訊號與三相輸出電壓命令,且在載波訊號為上升區間,以第一零向量控制下開關導通,且在載波訊號為下降區間,以第二零向量控制上開關導通(S12)。零向量切換方式可參見圖6所示,有零向量v0和零向量v7兩種切換方式。如圖5所示,在載波波峰時之零向量為v0,而在載波波谷時零向量為v7。再者,為了降低在電流箝位控制期間的切換損失,當箝位電流訊號SCC為載波訊號由波谷往波峰往上升(即上升區間或上升段)時(即第一個旗標訊號),則箝位電流控制將選擇零向量v0。反之,當箝位電流訊號SCC為載波訊號由波峰往波谷往下降(即下降區間或下降段)時(即第二個旗標訊號),則箝位電流控制將選擇零向量v7。 Then, compare the carrier signal with the three-phase output voltage command, and when the carrier signal is in the rising interval, the switch is turned on under the control of the first zero vector, and when the carrier signal is in the falling interval, the switch is turned on under the control of the second zero vector (S12) . The zero vector switching method can be seen in Figure 6. There are two switching methods: zero vector v 0 and zero vector v 7 . As shown in Figure 5, the zero vector at the peak of the carrier wave is v 0 , and the zero vector at the trough of the carrier wave is v 7 . Furthermore, in order to reduce the switching loss during the current clamp control period, when the clamp current signal S CC is the carrier signal rising from the trough to the peak (i.e., the rising interval or rising section) (i.e., the first flag signal), Then the clamp current control will select the zero vector v 0 . On the contrary, when the clamping current signal S CC is the carrier signal falling from the peak to the trough (i.e., the falling interval or section) (i.e., the second flag signal), the clamping current control will select the zero vector v 7 .
請參見圖13所示,其係為本發明以零向量控制功率轉換器的開關之第一實施例的具體示意圖。開關切換的電壓向量由三相電壓命令(Vref_max,Vref_mid,Vref_min)與載波比較來決定。在圖13中,將三相電壓命令分類為最大值(Vref_max)、中間值(Vref_mid)以及最小值(Vref_min)的電壓命令。當偵測到箝位電流訊號SCC,若在載波訊號為上升區間或上升段時,將三相電壓命令全部箝制在最小的電壓命令(Vref_min),即可產生零向量v0。另一方面,當偵測到箝位電流訊號SCC,若在載波訊號為下降區間或下降段時,將三相電壓命令全部箝制在最大的電壓命令(Vref_max),即可產生零向量v7。 Please refer to FIG. 13 , which is a detailed schematic diagram of the first embodiment of the present invention using zero vector to control the switch of the power converter. The voltage vector of the switch is determined by comparing the three-phase voltage command (V ref_max , V ref_mid , V ref_min ) with the carrier wave. In FIG. 13 , the three-phase voltage commands are classified into voltage commands with a maximum value (V ref_max ), a middle value (V ref_mid ), and a minimum value (V ref_min ). When the clamping current signal S CC is detected, if the carrier signal is in the rising range or rising section, all three-phase voltage commands are clamped to the minimum voltage command (V ref_min ), and the zero vector v 0 can be generated. On the other hand, when the clamping current signal S CC is detected, if all three-phase voltage commands are clamped to the maximum voltage command (V ref_max ) when the carrier signal is in the falling interval or falling section, the zero vector v can be generated 7 .
承前所述,本發明所提出的三相功率轉換器之輸出電流的箝位控制方法主要是以零向量取代將功率轉換器的開關全關閉的方式,來降低輸出電流的漣波,但此方式只適用於馬達操作於”電動機”模式下可行,若馬達此時操作 為”發電機”模式,則使用零向量操作是無法降低輸出電流的漣波,在這種情況下,還是要必須將功率轉換器的全部開關關閉,讓交流側的能量灌至直流側的煞車電阻Rdc來消耗,藉此降低交流電流大小,如圖14所示。 As mentioned above, the clamp control method of the output current of the three-phase power converter proposed by the present invention mainly uses a zero vector instead of fully closing the switch of the power converter to reduce the ripple of the output current. However, this method This is only applicable if the motor operates in the "motor" mode. If the motor operates in the "generator" mode at this time, using zero vector operation cannot reduce the output current ripple. In this case, the power must still be All switches of the converter are turned off, allowing the energy on the AC side to be poured into the braking resistor R dc on the DC side for consumption, thereby reducing the AC current, as shown in Figure 14.
然而,對馬達驅動器而言,其操作時不一定可知道目前馬達是操作在”電動機(motor)”模式或是”發電機(generator)”模式,因此,箝位電流控制策略上可以透過兩個箝位電流訊號,例如第一箝位電流訊號SCC1與第二箝位電流訊號SCC2來作為判定的依據,如圖15所示。具體地,若輸出電流iu,iv,iw的大小超過第一電流閾值時,其中第一電流閾值係對應作為判斷之用的第一箝位電流訊號SCC1時,意即若輸出電流iu,iv,iw的大小超過第一箝位電流訊號SCC1時,依據前述之方式切換至零向量。若馬達操作在”電動機”模式時,則輸出電流iu,iv,iw的大小可被抑制,因此輸出電流iu,iv,iw將會逐漸收斂,且可輸出較小的電流漣波。反之,馬達操作在”發電機”模式時,則輸出電流iu,iv,iw還是會持續變大。換言之,馬達操作在”發電機”模式時,僅透過單一電流箝位控制程序則無法有效地將輸出電流iu,iv,iw的大小進行抑制。 However, for the motor driver, it is not necessarily possible to know whether the motor is currently operating in the "motor" mode or the "generator" mode. Therefore, the clamping current control strategy can be implemented through two Clamping current signals, such as the first clamping current signal S CC1 and the second clamping current signal S CC2 , are used as the basis for determination, as shown in Figure 15 . Specifically, if the magnitude of the output current i u , iv , i w exceeds the first current threshold, where the first current threshold corresponds to the first clamping current signal S CC1 used for judgment, that is, if the output current When the magnitudes of i u , iv , and i w exceed the first clamping current signal S CC1 , switch to the zero vector according to the aforementioned method. If the motor operates in the "motor" mode, the magnitude of the output current i u , i v , i w can be suppressed, so the output current i u , i v , i w will gradually converge, and a smaller current can be output ripples. On the contrary, when the motor operates in the "generator" mode, the output currents i u , iv , and i w will continue to increase. In other words, when the motor operates in the "generator" mode, the output currents i u , iv , and i w cannot be effectively suppressed through a single current clamp control process.
因此,本案進一步可提供第二電流箝位控制程序,其係為更進一步地執行電流箝位控制程序,用以當輸出電流iu,iv,iw的大小超過第一電流閾值,但經過零向量操作仍無法降低輸出電流iu,iv,iw的漣波時,則啟動第二電流箝位控制程序。具體地,進一步判斷當輸出電流iu,iv,iw大於第三電流閾值時,其中第三電流閾值大於第一電流閾值,係透過控制三組開關橋臂的該等上開關關斷與該等下開關關斷,換言之,透過將功率轉換器的全部開關關閉,讓交流側的能量灌至直流側的煞車電阻Rdc來消耗,藉此降低交流電流大小。 Therefore, this case can further provide a second current clamp control program, which is to further execute the current clamp control program, so that when the magnitudes of the output currents i u , iv , and i w exceed the first current threshold, but after When the zero vector operation still cannot reduce the ripples of the output currents i u , iv , and i w , the second current clamp control program is started. Specifically, it is further determined that when the output current i u , iv , and i w is greater than the third current threshold, in which the third current threshold is greater than the first current threshold, the upper switches of the three sets of switch bridge arms are controlled to turn off and The lower switches are turned off, in other words, by turning off all switches of the power converter, the energy on the AC side is poured into the braking resistor R dc on the DC side for consumption, thereby reducing the AC current.
最後,當判斷輸出電流大於第二電流閾值時,啟動過電流保護程序(S13)。其中第二電流閾值大於第一電流閾值(亦大於第三電流閾值),並且第二電流閾值係對應作為判斷之用的第二箝位電流訊號SCC2。當輸出電流iu,iv,iw的大
小超過第二電流閾值時,意即當輸出電流iu,iv,iw的大小超過第二箝位電流訊號SCC2時,表示前述兩階段的電流箝位控制程序皆無法有效抑制輸出電流iu,iv,iw的大小,則功率轉換器100進入過電流保護,會將功率轉換器100所有的開關截止且系統停止運轉,進而達到降低輸出電流大小之目的。
Finally, when it is determined that the output current is greater than the second current threshold, the overcurrent protection program is started (S13). The second current threshold is greater than the first current threshold (also greater than the third current threshold), and the second current threshold corresponds to the second clamping current signal S CC2 used for judgment. When the magnitude of the output current i u , iv , i w exceeds the second current threshold, that is, when the magnitude of the output current i u , iv , i w exceeds the second clamping current signal S CC2 , it represents the aforementioned two stages. None of the current clamp control programs can effectively suppress the output currents i u , iv , and i w , then the
綜上所述,本發明係具有以下之特徵與優點: To sum up, the present invention has the following features and advantages:
1、本發明提出的三相功率轉換器之輸出電流的箝位控制方法,不使用將功率轉換器的開關全部關閉之策略,而是將功率轉換器切換至零向量,使馬達即使在箝位電流控制操作下,可以大幅地降低振動。 1. The clamp control method of the output current of the three-phase power converter proposed by the present invention does not use the strategy of turning off all the switches of the power converter, but switches the power converter to the zero vector, so that even if the motor is clamped Under current control operation, vibration can be greatly reduced.
2、本發明案提出之箝位控制方法,透過利用零向量來降低輸出電壓的跨壓,使輸出電流的漣波明顯下降。 2. The clamp control method proposed in the present invention uses the zero vector to reduce the cross-voltage of the output voltage, thereby significantly reducing the ripple of the output current.
3、本發明案提出之箝位控制方法,不僅可達成輸出電流的抑制,並且可避免輸出電流(能量)回灌至直流側電壓側。 3. The clamp control method proposed in the present invention can not only suppress the output current, but also prevent the output current (energy) from being fed back to the DC side voltage side.
4、當載波訊號為上升到波峰值時或為下降到波谷值時進行中斷電流箝位控制程序,相同的零向量接續控制開關導通,如此可降低切換損失。 4. When the carrier signal rises to the peak value or drops to the trough value, the current clamping control process is interrupted. The same zero vector continues to control the switch conduction, which can reduce switching losses.
以上所述,僅為本發明較佳具體實施例之詳細說明與圖式,惟本發明之特徵並不侷限於此,並非用以限制本發明,本發明之所有範圍應以下述之申請專利範圍為準,凡合於本發明申請專利範圍之精神與其類似變化之實施例,皆應包含於本發明之範疇中,任何熟悉該項技藝者在本發明之領域內,可輕易思及之變化或修飾皆可涵蓋在以下本案之專利範圍。 The above are only detailed descriptions and drawings of the preferred embodiments of the present invention. However, the characteristics of the present invention are not limited thereto and are not used to limit the present invention. The entire scope of the present invention should be determined by the following patent application scope. Subject to the present invention, all embodiments that are within the spirit of the patentable scope of the present invention and similar changes thereof shall be included in the scope of the present invention. Any person familiar with the art can easily think of such changes or modifications in the field of the present invention. Modifications may be covered by the following patent scope of this case.
S11~S13:步驟 S11~S13: Steps
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TW201014146A (en) * | 2008-05-14 | 2010-04-01 | Nat Semiconductor Corp | System and method for an array of intelligent inverters |
CN104682692A (en) * | 2013-11-29 | 2015-06-03 | 技嘉科技股份有限公司 | Power management unit |
TW201545456A (en) * | 2014-05-30 | 2015-12-01 | Delta Electronics Shanghai Co | Voltage-adjusting device and method in power converting system |
TWI543640B (en) * | 2012-09-07 | 2016-07-21 | 美國博通公司 | Low-quiescent current headset driver |
US20190372567A1 (en) * | 2017-02-28 | 2019-12-05 | Mitsubishi Electric Corporation | Semiconductor device and power conversion system |
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TW201014146A (en) * | 2008-05-14 | 2010-04-01 | Nat Semiconductor Corp | System and method for an array of intelligent inverters |
TWI543640B (en) * | 2012-09-07 | 2016-07-21 | 美國博通公司 | Low-quiescent current headset driver |
CN104682692A (en) * | 2013-11-29 | 2015-06-03 | 技嘉科技股份有限公司 | Power management unit |
TW201545456A (en) * | 2014-05-30 | 2015-12-01 | Delta Electronics Shanghai Co | Voltage-adjusting device and method in power converting system |
US20190372567A1 (en) * | 2017-02-28 | 2019-12-05 | Mitsubishi Electric Corporation | Semiconductor device and power conversion system |
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