1290415 九、發明說明： 【發明所屬之技術領域】 本發明係關於一種無感測器換相電路及三相換相信號 檢測方法，尤指一種三相無刷直流馬達之無感測器換相電 路，係以更精簡簡單電路設計，實現非感測式換相偵測功 能0 【先前技術】 目别應用在二相無刷直流馬達的換相電路概分為感應 式及非感應式，其中感應式係主要於馬達驅動電路中使用 三顆霍爾感測器，該霍爾感測器係檢測馬達線圈換相時的 電磁變化，進而將檢測信號予以輸出至馬達驅動〗c，供 馬達驅動I C依照換相信號’而提供電流予下一個線圈， 令馬達能順利運轉。另-種非感應式換相電路即是不採用 霍爾感測器，藉由抓取馬達三相線圈的端電壓及反電動勢 的變化:配合相關電路的設計，取得三相線圈的換相信號， 意即’藉由取得反電動勢的^士雜 电勁労的k唬，取代霍爾感測訊號；特 別是在感測到反電動勢盘中松h _ 士 另/、τ性點相父處，使用零交越點來 偵測出馬達轉子的區間位置’其中只要零交越點之相位只 要延遲3 0度，即為有效的換相信號。 =應式換相電路因採用三顆單價高的霍爾感測 故成本上相較該非感應換相電路會較高，而且還有安 :環境的限制。某些特殊場合下馬達在長時 生高溫’會影響霍爾感測器換相檢知的可靠度 式換相電路雖較感應式換相電路來得便宜，但其電路= 1290415 亦隹度亦相對變得更高，並且有轉速範圍限制。 明茶閱第五圖所示，係為目前常見的非感應式換相電 . 路，其包含有： 三比較器； • 三組三級濾波電路，各組三級濾波電路係包含有一移 相電路、一直流濾波器及一切換頻率濾波器，其中三組三 j濾波電路的移相濾波器分別連接至三相馬達線圈的端電 _ 壓，而二組切換頻率濾波器的輸出端則連接至對應比較器 - 的正輪入端；及 • 中性點電壓產生電路，係提供一固定電壓，作為中 性點電壓之用，係共同連接至該比較器的負輸入端。 上述換相電路需取得三相線圈的端電壓，並且產生一 中性點電壓，其中該中性點電麼並非馬達本體標準的輸入 輸出介面，因此必需要另外經過處理才能取得，至於線圈 電t要配合中性點電壓換异出換相脈波信號前，由於線 鲁圈端電壓信號包含有脈寬調變信號，所以為消除該脈寬調 變信號對於換相信號的影響而降低相角誤差，需分別經過 三道濾波器，將其濾除後再輸入至比較器，以與中性點電 壓進行換相信號的比較。然而，也因為採用了三級濾波器， 而使得估測出的換相脈波信號易受到馬達轉速的影響，而 且由於該中性點電壓為固定電壓，故僅能應用低速比的無 刷馬達上，較適合固定轉速的無刷馬達使用。 【發明内容】 本發明的主要發明目的係提供一種三相無刷i流馬達 1290415 之無感測it換相電路及三相換相信號檢測方法，係以精簡 勺包路σ又计，藉由取得三線圈的端電壓，不需額外的中性 點電壓’即能取得相位延遲3〇度的有效換相信號。 '、達述目的所使用的主要技術手段係令該無感測器 換相電路包含有： β、三組低通濾波器，係分別連接至三相線圈的對應端電 壓’各低通濾波器係為一 R C濾波器，以取得各線圈的平 均端電壓；及 。。三比較器，各比較器係包含有正、負輸入端，各比較 器的正輸入端係連接至對應的尺C濾波器，而負輸入端則 分別與相鄰R C濾波器輸出端連接。 二相無刷馬達係由一馬達驅動電路對三相線圈順序驅 動’因此相鄰線圈的端電壓係包含有與反電動勢相差12〇 ，相位差的特徵，本發明藉由此—㈣，令各比較器係取 得三相線圈中的兩相鄰線圈的平均端電壓，進行比較後， 即可取付-脈波信號’而此—脈波信號即會落後反電動勢 又相位由方、萑爾感測知號所感應出的換相信號與反電 動勢同樣落後30度相位差，因&，本發明所預估的脈波 ^號即可作為有用的換相信號。 【實施方式】 首先請參閱第一圖所示 路（1 0 )的一較佳實施例 二組低通濾波器（1 1 接至三相線圈的對應端電壓 ’係為本發明無感測器換相電 其包含有： 3 )〜（1 1 C )，係分別連 (V a〜V C )，各低通濾波 1290415 叩（1 1 a )〜（1 1 c )係為一 r ◦濾波器，以取得各 線圈的平均端電壓；請配合參閱第二圖，係於馬達驅動電 路輸出100%及50%週期（DUTY CYCLE)的脈寬調變信號下， 三相線圈的各線圈端電壓（V a、v b〜v c )波形變化； 及 比季交器 C, di )1290415 IX. Description of the invention: [Technical field of invention] The present invention relates to a sensorless commutation circuit and a three-phase commutation signal detection method, in particular to a sensorless commutation of a three-phase brushless DC motor The circuit is designed to achieve non-sensing commutation detection function with a simpler and simpler circuit design. [Prior Art] The commutation circuit applied to the two-phase brushless DC motor is divided into inductive and non-inductive. Inductive system mainly uses three Hall sensors in the motor drive circuit. The Hall sensor detects the electromagnetic change when the motor coil is commutated, and then outputs the detection signal to the motor drive 〖c for motor drive. The IC supplies current to the next coil in accordance with the commutation signal ', allowing the motor to operate smoothly. Another kind of non-inductive commutation circuit is to use the Hall sensor instead of the change of the terminal voltage and back electromotive force of the three-phase coil of the motor: with the design of the relevant circuit, the commutation signal of the three-phase coil is obtained. That means 'to replace the Hall sensing signal by the k唬 of the electric power of the anti-electromotive force; especially in the sense of the anti-electromotive force disk, the loose h _ 士士/, τ sexual point father, The zero-crossing point is used to detect the position of the motor rotor's section, where the phase of the zero-crossing point is only a delay of 30 degrees, which is a valid commutation signal. = The application-type commutation circuit is higher in cost than the non-inductive commutation circuit because of the three high-priced Hall sensing, and there is also an environmental limit. In some special occasions, the motor generates a high temperature for a long time, which will affect the Hall sensor's commutation detection. The reliability of the commutation circuit is cheaper than the inductive commutation circuit, but its circuit = 1290415 is also relatively low. It becomes higher and has a speed range limit. Ming tea is shown in the fifth figure, which is the current common non-inductive commutation circuit. It includes: three comparators; • three sets of three-stage filter circuits, each group of three-stage filter circuits including a phase shift a circuit, a DC filter, and a switching frequency filter, wherein the phase shifting filters of the three sets of three-j filter circuits are respectively connected to the terminal voltage of the three-phase motor coil, and the outputs of the two sets of switching frequency filters are connected To the positive wheel of the corresponding comparator - and • the neutral point voltage generating circuit provides a fixed voltage for neutral voltage connection, which is commonly connected to the negative input of the comparator. The above-mentioned commutation circuit needs to obtain the terminal voltage of the three-phase coil, and generates a neutral point voltage, wherein the neutral point is not the standard input and output interface of the motor body, so it must be processed separately to obtain the coil electric power. Before the neutral point voltage is exchanged for the out-of-phase pulse signal, since the line voltage signal of the line has a pulse width modulation signal, the phase angle is reduced to eliminate the influence of the pulse width modulation signal on the commutation signal. The error needs to be filtered through three filters and then input to the comparator for comparison with the neutral point voltage for the commutation signal. However, because of the use of a three-stage filter, the estimated commutation pulse signal is susceptible to the motor speed, and since the neutral point voltage is a fixed voltage, only a low speed ratio brushless motor can be applied. It is more suitable for brushless motors with fixed speed. SUMMARY OF THE INVENTION The main object of the present invention is to provide a three-phase brushless i-flow motor 1290415 non-sensing it commutation circuit and a three-phase commutation signal detection method, which is based on the simplification of the package path σ By obtaining the terminal voltage of the three coils, an effective commutation signal with a phase delay of 3 〇 can be obtained without an additional neutral point voltage. 'The main technical means used for the purpose of Dashu is that the non-sensor commutation circuit contains: β, three sets of low-pass filters, respectively connected to the corresponding terminal voltage of the three-phase coil' each low-pass filter Is an RC filter to obtain the average terminal voltage of each coil; . The three comparators each have positive and negative inputs, the positive input of each comparator is connected to the corresponding scale C filter, and the negative input is connected to the adjacent R C filter output. The two-phase brushless motor is sequentially driven by a motor drive circuit to the three-phase coils. Therefore, the terminal voltage of the adjacent coils includes a phase difference of 12 与 from the counter electromotive force, and the present invention uses the above-mentioned (four) The comparator obtains the average terminal voltage of two adjacent coils in the three-phase coil, and after comparison, the pulse signal can be taken. The pulse signal is behind the back electromotive force and the phase is sensed by the square and the mull. The commutation signal induced by the knower is also 30 degrees behind the back electromotive force. Because of the &, the pulse wave estimated by the present invention can be used as a useful commutation signal. [Embodiment] Referring first to a preferred embodiment of the road (10) shown in the first figure, two sets of low-pass filters (1 1 connected to the corresponding terminal voltage of the three-phase coil) are the sensorless sensors of the present invention. The commutation electric power includes: 3) ~(1 1 C ), which are respectively connected (V a~VC), and each low-pass filter 1290415 叩(1 1 a )~(1 1 c ) is an r ◦ filter To obtain the average terminal voltage of each coil; please refer to the second figure, which is the pulse width modulation signal of the motor drive circuit output 100% and 50% cycle (DUTY CYCLE), the voltage of each coil end of the three-phase coil ( V a, vb ~ vc ) waveform change; and than the quadrant C, di )
V丄乙 C a )〜（1 2 c )係包含有正、負輸入端，各比較器（丄 =3 )〜（1 2。）的正輸人端係連接至對應的低通滤波 益（1 1 a )〜（1 1 c ) ’而負輸人端則分別與相鄰低 通濾波器（1 1 a )〜（i丄c )輸出端連接。 由於馬達驅動電路係順序驅動三相線圈，因此相鄰線 圈的端電壓係包含有與反電動勢相差3〇度相位差的特 :’而本發明即是藉由此-特徵，令各比較器（12a) (1 2 C )係、取得三相線圈中的兩相鄰線圈的平均端電 i(Va)(Vc)，如第三圖B、 « u D υ所不，進行比較後， 即可取得一落後反電動勢（ 男〔如弟二圖A所示）30度相位的 、波仏5虎（V a —V c )，如第三圖D所示。 請再配合第四圖A〜E所干，戸卩头-得的1 * 11所不，即為第三圖實際量測而 于的电壓波形圖，其中第四圖D、£ 仕山十 係為本發明最後預 出來的換相脈波信號，與直接使用 脈寬信號相同。 &應«所私知的 由上述說明可知，本發明吝 係包含有： …產生換相脈波信號的方法， 取传二相線圈平均端電壓· 1290415 對三組平均端電壓中各兩兩相鄰線圈的平均端電壓相 減，取得三組脈波信號；及 令二組脈波信號為三相換相信號。 是以，本發明係為一種非感應式的換相電路，相較於 目前常用的換相電路不僅完全省去中性點電壓的產生電 路，對於處理一組端電壓亦僅只需要一組低通濾波器，相 較之下，對於馬達轉速對換相電路的影響可大幅減低，確 實為一相當精簡電路，有助於簡化非感應式換相電路，降 低製作成本。 【圖式簡單說明】 第一圖·係本發明換相電路一較佳實施例的電路圖。 第二圖：係三相無刷馬達之三線圈端電壓波形示意 圖。 〜 第三圖A〜D :係本發明應用於三相無刷馬達，所量 測而得的反電動勢、二相鄰線圈之端電壓及一預估換相信 號的示意波形。 第四圖A〜E ·係本發明第三圖B〜D的實際量測波 形圖。 第五圖：係既有一非感應式換相電路的電路圖。 【主要元件符號說明】 (1 0 )無感測器換相電路 (1 1 a )〜（1 1 C )低通濾波器 (1 2 a )〜（1 2 c )比較器 (5 〇 )非感應式換相電路 1290415 (51a)〜（51c)比較器 • (52a)〜（52c)移相電路 . (5 3 a )〜（5 3 c )直流濾波器 (5 4 a )〜（5 4 c )切換頻率濾波器 (5 5 )中性點電壓產生電路V丄B C a )~(1 2 c ) contains positive and negative inputs, and the positive input terminals of each comparator (丄=3)~(1 2) are connected to the corresponding low-pass filter benefits ( 1 1 a )~(1 1 c ) ' and the negative input terminals are respectively connected to the outputs of the adjacent low-pass filters (1 1 a ) to (i丄c ). Since the motor drive circuit sequentially drives the three-phase coils, the terminal voltages of the adjacent coils include a phase difference of 3 degrees from the counter electromotive force: and the present invention uses the feature to make the comparators ( 12a) (1 2 C ), obtain the average terminal power i(Va)(Vc) of two adjacent coils in the three-phase coil, as shown in the third figure B, «u D ,, after comparison, Obtain a backward back electromotive force (male (as shown in Figure 2) of the 30 degree phase of the wave, 5 waves (V a - V c ), as shown in the third figure D. Please cooperate with the fourth figure A~E, and the 1~11 of the gimmick-does is the voltage waveform of the actual measurement of the third figure, the fourth figure D, the Shishan ten series The commutated pulse wave signal finally obtained in the present invention is the same as the direct use pulse width signal. As can be seen from the above description, the present invention includes: ... a method for generating a commutation pulse wave signal, taking the average phase voltage of the two-phase coil · 1290415 for each of the three groups of average terminal voltages The average terminal voltages of adjacent coils are subtracted to obtain three sets of pulse wave signals; and the two sets of pulse wave signals are three-phase commutation signals. Therefore, the present invention is a non-inductive commutating circuit, which not only completely eliminates the neutral point voltage generating circuit, but also only needs a set of low pass for processing a set of terminal voltages. In contrast, the effect of the motor speed on the commutation circuit can be greatly reduced. It is indeed a relatively simplified circuit, which helps to simplify the non-inductive commutation circuit and reduce the manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram of a preferred embodiment of a commutation circuit of the present invention. The second picture is a schematic diagram of the voltage waveform of the three coil ends of the three-phase brushless motor. ~ The third figure A to D: The present invention is applied to a three-phase brushless motor, and the back electromotive force measured, the terminal voltage of two adjacent coils, and a schematic waveform of a predictive change signal are used. Fourth Figures A to E are actual measurement waveform diagrams of Figs. B to D of the present invention. Figure 5: A circuit diagram of a non-inductive commutation circuit. [Main component symbol description] (1 0) No sensor commutation circuit (1 1 a ) ~ (1 1 C ) low pass filter (1 2 a ) ~ (1 2 c ) comparator (5 〇) non Inductive commutation circuit 1290415 (51a) ~ (51c) comparator • (52a) ~ (52c) phase shift circuit. (5 3 a ) ~ (5 3 c ) DC filter (5 4 a ) ~ (5 4 c) switching frequency filter (5 5 ) neutral point voltage generating circuit