TWI275238B - Rotor position/speed estimating method for micro permanent magnet synchronous motors - Google Patents

Abstract

This invention proposes a rotor position/speed estimation technique for micro permanent magnet synchronous motors. When the motor is operating in the mid and low speed, the stator current is discontinuous. The back emf of the motor can be detected while the stator current reaches zero. On the other hand, when the motor is operating in the high speed range, the stator current is continuous. Then, by detecting the phase voltage and phase current, the back emf of the motor can be computed. The rotor position can be derived from the back emf. The rotor speed can be computed according to the rotor position with the difference operating. Finally, a closed-loop adjustable speed control can be achieved. The closed-loop drive system has an adjustable speed range from 600 r/min to 36000 r/min.

Description

1275238 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 [Prior Art] A known method uses an induced voltage of a non-excited phase of a motor to obtain a back-embride zero crossing point. For example, in the Republic of China Patent No. 588505, one of the sensorless brushless DC motor control systems is a waveform that compares a voltage comparison device and a sampling trigger signal with the detected floating phase voltage through a simple circuit. After processing, a pulse wave number of a zero-crossing point of the back EMF is obtained, and then the signal is used to estimate the angle of the rotating shaft. However, the disadvantage of the above-mentioned Patent No. 588505 is that the estimated angular position of the obtained shaft is not high, and it is easy to generate a large estimation error. SUMMARY OF THE INVENTION The technical problem to be solved by the present invention is that the control of the miniature permanent magnet synchronous motor must be prayed (four)/speed bump to determine the size of the stream and the timing of the input, and to achieve commutation and closed loop speed control. Therefore, it is common to use a shaft-sharp component to make the motor's misunderstanding and calculate the shaft speed: generally use light to block n, the -chain slotted disc on the shaft, or use the Huo, - A permanent magnet mounted on the shaft. It is also possible to detect the angle of the shaft using an encoder (face) = resolver. However, these additional detection devices not only increase the cost and space of the system, but also are susceptible to noise interference from the wires and reduce their reliability. The main object of the present invention is to provide a control device for mini-permanent magnet synchronous Marais translation. The angle of the shaft is estimated by the relationship between the three opposite potentials and the angle of the shaft. When the motor is running at a low speed, the zero current of the coffee stator current is instantaneously subjected to the voltage of each phase, ,", and vice versa. When the motor is running at a high speed, the stator current is continuous, the conduction phase, the phase excitation voltage and the excitation phase On the side of the current, and through simple calculation, the estimated three potentials are synthesized, and the relationship between the female standard conversion and the trigonometric function is obtained to obtain the estimated value of the shaft angle of 1275238. Finally, the estimated angle of the shaft is feedback and closed. Development of a loop drive system. The technical means for solving the problem of the present invention: The technical means adopted by the present invention for solving the problems of the prior art is to estimate the back EMF by a current variation characteristic of a miniature permanent magnet synchronous motor. When the stator current is discontinuous at medium and low speeds, the current is detected at zero moment; when the high speed and stator current are continuous, the phase voltage and phase current signals are detected, and the data is fed back by the interface device. Synthesize three opposite potentials in the shaft angle estimator, corresponding to the shaft angle via three opposite potentials

The functional relationship of the position estimates the angle of the shaft, and the angle of the shaft is obtained by differential operation to obtain the speed of the motor. The specific method and control flow employed in the present invention will be further illustrated by the following examples and the accompanying drawings. [Embodiment] Referring first to the first figure, a block diagram of a closed loop speed control driving system of the non-rotation angle detecting element of the present invention is shown. The motor three-phase current signal Z, and the side motor three relative ground voltage signal u%~ are detected by the Hall effect current detector. The voltage signal is converted into a digital signal by an analog/digital converter, and is fed back to the micro-computer through the interface device, and the feedback current/voltage signal is used to estimate the back electromotive force of the micro-magnet synchronous motor using the back electromotive force estimator. The angle estimation method of the motor is estimated by the simple conversion of the rotation angle estimator and the simple mathematical operation of the trigonometric function to estimate the rotation axis. The rotation angle of the rotor is calculated by the operation of the motor, and the set speed command < and the estimated torque is subtracted to the speed error Δ%, and then the motor is required to calculate the electric motor required by the speed controller. Baguang. Then, the current command r cooperates with the estimated angle to calculate the phase current command to send the current command and the feedback of the actual three-phase electric method gas through the digital/analog converter to the current wave width modulation controller. The three-phase wave width of the motor is generated and the 1L is changed to π, V, V, and m. Finally, the trigger signal is sent to the inverter to generate the required voltage and current to drive the motor m = change ^ the motor is closed. ",, ♦ Xianfan's 7 ^ 275238 miniature permanent magnet synchronous motor back electromotive force estimation principle is as follows: Micro Yongbu motor # step read and cut to drive control, generally two-phase conduction =: phase cut off 'that is - Only two switches are turned on, and the remaining four switches are all off. The control ^ = as shown in the second figure, 'Using the wave width modulation technology to provide the upper arm power switch to do the work, such as ^ three Riding the display, to complete the magnetic, 畐ft magnetic synchronous motor's due to the slotless stator structure, providing a large magnetic field space, the second and the m air gap in the 'stator side coil winding is also due to the air gap space = = small, value, fine value is usually about 5 〇 ohms of the traditional AC motor: up to its wire chaotic winding (four) sense only a few micro Henry, the resistance is continuous phenomenon H time constant is less than a few microseconds, causing the stator coil current is not Even it adjusts the sub-domain width _ stop time (method 1 in the motor, low, pro, military L ί two different estimation methods. Among them, the method α is mainly used to open the power to stop the current discontinuity phenomenon , Lee is commutating conduction. Among them, 楹々^ AW 守, /, poke, lower arm open Then, it is used as a guide. A, , and 疋 Ο Ο 上 上 上 上 上 上 上 上 上 上 上 上 上 上 上 上 上 上 上 上 上 。 。 。 。 。 。 当 当 当 当 当 当 当 当 当 当 当 当 当 当 当 当 当 当The neutral point is reduced by the two temples, as shown in the fourth picture of the brothers. Ma Xizhi (1), (2), (7). According to the R test point, the dragon equation can be referenced to the potential as follows: 'Replace the grounding point ° reference potential instead of the original neutral point' = the new voltage wire type is as follows (4), (5 dt a · · · · ................. ......... ............................Formula 1)

Vbn=h^ + L^k + e dt b..................................... .....................(2) W + ii+e dt c................... ........................................... (3) 1275238 · Va〇— VDiode = + L —- + e +V dt a no................. vb〇=vm〇s =^ar-L^i + e +v dt b . .................... Vco ~ Vno ec............ ea+eb+ec=0....... In the formula, V(7) is a, έe is relatively referenced to electric dust, and ia, h, ic ' is Cl, b. Only ^ stator current, 6q, the heart is the opposite potential of βέf, widely the stator coil resistance, // is = sub-ring inductance 'H becomes ^ small e-phase stator current variation, 汾 is the inter-day spear in the intersection of 'Vm for the flywheel The two-pole voltage 'v_ is the power switch, ^ is the neutral dream to ground voltage. The new voltage equations derived from the above, (5), (6) and hypothetical motors

Under the trapping-phase equilibrium, when the back EMF is zero, as in equation (7), the back EMF equation can be obtained by 彳 & J e = v — ir — T __Li, ······Formula (8) _····Formula (9) ···•Formula (10) α α〇α dt ^3 co^V〇ffset eb =vb〇+iar + L^f-~v -v dt 3 offset · 2 ' Vc〇offset V〇ffs^ et V Diode ....................(11) After finishing, the simple back EMF equation is obtained as follows: For the back EMF offset voltage, because the micro-permanent brushless motor junction current is cut off at the pulse wave, because the resistance value is much larger than the inductance value, the motor is A-type, J is easy to cause current discontinuity, when the stator current is The zero-time stator current is smaller than its two-seven, zero, as shown in the fifth figure, and the above formula is substituted into the back-potential equation (8f rates are all ea = Va〇^co ^offset ········•• (12) 9 ^275238 eb ~~ Vbo c〇~Voffset .................................... .....................Formula (13) 2 e^^vc〇-voffset................. .................................................formula (14) from the above-mentioned anti-potential side It is stated that the estimation of the back EMF of the micro permanent magnet synchronous motor at low speed operation needs to detect the three-phase stator ground reference voltages V% and h, and can be obtained through simple calculation. The above discussion is based on mode 1. The criterion is to extend the method to the six states of the six-step square-wave switching mode, and to align the mode 1 to mode ό, the back-potential equation of the current discontinuity state, as shown in Table 1 below: Table - Mode of current discontinuity 丨To mode 6, three opposite potential equation switching mode 1T / τΒ I±tc

Mode 3 V 7V Mode 4 ------ - Contrast potential - Vco^Voffset '^Vbo^V offset eb ^ ^ Contrast potential 〇 opposite potential ^ 1 2 = ~^Vco^V Offset b〇^ offset s- ----- 2 ΐ~ ec =Vco ^^Vbo~Voffset Ό a co ao Voffset 2 offset co ^offset 2 = -ZVco~V offset Mode 5 b〇V offset eb ^^bo-voffset ec =Vc〇- -^b〇^〇

Offset ea =vao--v mode 6

π TV 2 ao offset A = vc〇 Ί a brother

Exaggerated ^ go to B main ^ motor south speed operation and load ^ ^ sub-current change characteristics for Lian,, =, evil 'utilization work ~ off conduction instant 'detecting the floating phase of the ground to the second, the third picture Mode i is shown, where mode i is defined as _ upper arm conduction, lower arm conduction, and e phase not. When the α-phase upper arm switch is turned on, its equivalent circuit, such as 1275238, is shown in Figure 6. Ground the point. The reference potential replaces the original neutral point "reference potential. The new voltage is as light as public and private 15), (16), (17):

ΚΆ+1^ + 6α+'. ............. U .....................Formula (15) v = - Bu _L^ + eb+va Dt -....................................Formula (16) ~. Η〇..............................Formula (17) where ν is also a DC confluence The discharge voltage is derived from the new voltage equations (15), (16), (17) and (7) the sum of the back EMFs under the three-phase equilibrium. After finishing, the #列列篇名 equation can be obtained: 于.r dia 1 1 ea=^a〇-la^L^^3Vc〇^3VdC................................. ...formula (18) r dia 1 1 eb=vbo+iar^L---vco--Vdc......................... .......... 2 1 p, -v--V 1 ....... c 3 c〇3 ·· ................ ...............................(20) Micro permanent magnet synchronous motor is operated at high speed and loaded due to internal circuit The current modulation relationship forms a continuous current phenomenon, so the stator current and current rate will affect the estimation of the back EMF. However, since the stator inductance of the micro permanent magnet synchronous motor is a few micro-henry, the current change rate is not large at high speed. The product of the inductance and the rate of change of current has little effect on the estimation of the back EMF. Therefore, considering this consideration, assuming that the power switching voltage is small, 〇' will be the above formula of the back EMF equation (18), (19), (20 ), after finishing, get a simple equation of back EMF as shown in equations (21), (22), (23): =乂r

Formula (21) ea

Formula (22) 1275238

CO

V dc.................. ..... Equation (23) Estimated t丨 on the t-potential wire type, the micro-constant magnetic synchronous motor at high speed operation Estimated, the second non-excited phase stator to ground reference

L, and the DC bus 懕 懕 v 4 ^ ^ ^ /;, L is discussed in the transition of i ° on the off, and 敕 mining, ", / / method to six six-step square wave switching mode of the six two households $1 to mode 6, the inverse equation of the current continuous state, as shown in the following table

The estimated two-reduction potential signal core of the above-mentioned, the coordinate system of the stator is a three-phase carrier of the stator, and the DC-element equation contains the DC component offset value, and the -σ difference is convenient and effective to eliminate the DC component in the equation. This article will use the coordinate 12 I275238, the 'one axis coordinate converted from the az? c car to the stationary coordinate, the beta axis coaxial' and the alpha car is poor. The rear 々 axis is 90 degrees. The conversion formula is as follows: V 1 A! 1 Ί V Α A 0 ^ V3 eb 2 Y Λ _ . Equation (24)

eP inverts θ = tan~l β ........................................ ...........Formula (25) Control =:: degree soft ::: two revolving shaft purchase (four) closed - ώ e .............. ................................................formula( 26) > θ where θ6 is the estimated motor angle, and also the derived result of the estimated angular velocity of the shaft. It is known that the angle estimation rule proposed in this paper directly detects the voltage and current of the stator. 'With simple calculations, the back EMF and the angular position of the shaft can be estimated without additional hardware. It can be used both at high and low speeds. The axis estimation process is as follows: From the three opposite potential equations compiled in Tables 1 and 2 above, the estimation rule can be summarized as a flow chart for the microprocessor to calculate the angle of the shaft, as shown in the seventh figure. Firstly, the current sampling is judged by the three-phase stator current input in the current control loop. According to the switching mode, only one phase upper arm is turned on in each switching mode, and the other phase lower arm is turned on, and the remaining phase is not switched. This state is defined as the upper arm conducting to the X phase, and the current flowing through the phase coil is 匕; the lower arm is conducting as a phase, and the current flowing through the phase is non-conducting to / phase. The angle of the shaft is estimated according to the current & of the upper arm conducting phase. The current is continuously judged or not. When the current is discontinuous, the X-phase current is equivalent to zero. At this time, only the three-phase stator line is measured. 13 1275238

The voltage of the loop to the DC bus grounding point ~, v, v > according to the middle and low speed back EMF estimation rule, estimating the upper arm conducting opposite potential g, the lower arm conducting the opposite potential & and the non-conducting opposite potential q ' The back EMF is synthesized into three opposite potential hearts, α, & When the current is continuous, the X-phase current is not zero. At this time, it is only necessary to measure the voltage v/° of the coil of the non-conducting phase to the grounding point of the DC bus and the current of the upper arm conducting phase coil 4, and the bus voltage The V operation operates at the frontal voltage and does not require special measurement. According to the high-speed back EMF estimation rule, it is estimated that the upper arm conducts the opposite potential Q, the lower arm conducts the opposite potential 々 and the non-conducted opposite potential 4, whether it is medium or low speed or high speed. The back EMF estimation rule finally synthesizes three opposite potentials, Q, and, and through k庋I conversion to eliminate DC components. Since the three opposite potentials have a function relationship with the angular position of the rotating shaft, a higher resolution motor angle can be obtained as an estimate of the angular position via the correction of the inverse tangent function and the inverse tangent function. Experimental results: : 1 shellfish is used to drive the permanent magnet synchronous motor drive system. Several experimental results are shown. The eighth figure shows the measurement of the beta phase stator current at 10,000 rpm. The ninth figure shows the estimated value of the opposite potential of 4^0000, β 〇 , + m 二古', and the magnitude of the back EMF is close to 2·8 volts. Tenth-two..., 10000 rpm, using the coordinate conversion to calculate the back-potential change rate of the vertical axis by the three opposite potentials ~, , and with the horizontal axis of ~. At the 10th turn/min, the estimated angle of the shaft and the actual motor turn are the angle error. The value of the Γ Γ Λ 娜 00 00 rpm, the estimated angle of the shaft and the actual value are temporarily off the motor angle. The fourteenth figure is the speed _ turn / minute down, = the figure speed 3_, the transient speed rang the Newton-meter 贞 ^ ^ Figure 4 speed is turned / min, the added rated load 0.275 millimeters to the rated load Tfifl should be the t seven figure for the speed of 30000 rev / min, for the speed of 10000 charm / \ ^ cattle page meter load speed response measurement map. The 18th £1, the turn of the 10,000 rpm, the positive reversal of the temporary bear music, the eight map speed surface turn / sub-down, the positive and negative reversal angle map speed, the nineteenth picture is the rise, the twentieth Increase, 1 forward shift phase angle, the speed can not be raised as a weak magnetic control, the speed response of the forward shift phase is not moved forward phase shift speed «speed response = 14 1275238 ί speed weak magnetic control' forward shift phase response The measurement is not; the angle is increased to 36_rev/min. The twenty-second picture shows the high-rotation weak-magnetism control, and the relationship between the actual speed and the speed-to-speed ratio. BRIEF DESCRIPTION OF THE DRAWINGS The figure is a block diagram of the micro-permanent magnet synchronous motor rotation/speed estimation of the present invention. The second picture is the sound map of the micro-permanent magnet synchronous motor discriminator (overhang). The second figure is a sequence diagram of the conventional pulse width modulation and commutation mode. ~ The fourth figure is the equivalent circuit of the power conversion red arm switch cutoff and the lower arm _ & conduction. The fifth graph is a graph showing the relationship between the current and the phase voltage of the present invention. The sixth figure shows the equivalent circuit of the invention of power conversion red correlation Γ / conduction and downlink. The seventh picture is the flow chart of the _ _ step motor _ limb side. The eighth figure is a measurement diagram of the stator current of the phase of the invention at a speed of 10 rpm. The ninth figure is a measurement diagram of the rotational speed of 1G_rev/min τ, α relative to ground according to the present invention. The tenth figure is the estimated value of the three-extinguishing potential under the rotation speed of 10_rev/min according to the present invention. The tenth-figure is an estimation chart of the rate of change of the back electromotive force with the rotation speed of 1 〇 _ rpm in the present invention and the horizontal axis as the vertical axis. The twelfth figure is the relationship between the estimated Na and the actual motor shaft angle. The thirteenth figure is the angular error of the value of the transition value of the _ speed 诵 0 rpm. , , / , and fourteen pictures are the measurement charts of the transient speed response of the present invention under the speed _ turn / minute. The fifteenth figure is a measurement chart of the transient speed response of the present invention at a rotational speed of 3GGGG rpm. The sixteenth map of the county _ speed painting turn / sub-under, plus the rated load of the county speed response measurement map. The seventeenth figure is a steady response measurement chart of the rated load at a speed of 3_0 rpm. ^ The eighteenth_本发_速1G_转/分下, positive and negative (four) speed response amount 1275238 mapping. Nineteenth = this is the date of the joint speed _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ The Eleventh® system invented the high-speed Lions, the transient velocity response map of the forward commutation angle. The twelfth figure shows the high-rotation weak-magnetism control of the present invention, and the forward-shifting at different angles corresponds to the relationship between the actual rotational speed and the rated rotational speed ratio.

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Claims (1)

1275238 Pickup, patent application scope: L A miniature permanent magnet synchronous motor shaft angle/speed estimation method, which uses a back EMF estimation signal to convert the shaft angle signal to replace the signal of a shaft detecting component, and provides the motor shaft angle/speed. Accurate estimation. 2. According to the micro-permanent magnet synchronous motor shaft angle/speed estimation method of claim 1 of the patent scope, the motor uses the wave width modulation technology to estimate the opposite potential of the motor in two different current states. 3. According to the method of claim 2, the two different current states are provided by the power converter to provide continuous and discontinuous current characteristics caused by the on and off states of the upper arm power switch. 4. According to the method of the third paragraph of the patent application, using two different current states to estimate the three opposite potentials can be divided into two different estimation modes: method A and method B; method A is the wave width modulation cutoff time. The estimation method; the method B is an estimation method when the wave width modulation is turned on. 5. According to the method of claim 4, the method A of the motor's back EMF estimation principle is that when the current is discontinuous, the current is zero and the relative ground voltage is detected instantaneously, so the current can be assumed. And the current change is zero, and the resultant three opposite potential is obtained. 6. According to the method of claim 4, the method B of the motor is based on the principle of estimating the back EMF. When the current is continuous, the current is not zero, and the non-excited relative ground voltage and the excitation phase are detected. The current can be assumed to be known as the DC busbar voltage, and the resultant three opposite potentials are obtained. Further, according to the method of claim 5 or 6, the six states of the six-step square wave switching mode are used to estimate the three opposite potentials of the micro permanent magnet synchronous motor, and three opposite potential corresponding/(9) degrees can be obtained. The signal of the motor angle. 8. According to the opposite potential signal of the seventh paragraph of the patent application, the signal of the angle and speed of the shaft is obtained through the simple coordinate conversion and the trigonometric function. 9. According to the accurate estimation of the motor shaft angle/speed provided in item 8 of the patent application scope, feedback of a shaft angle/speed data to complete closed loop control and four quadrant control, and improve the speed control range by The law of high-speed weak magnetic field, the excitation current conduction angle is modulated, and the control range is improved. 17