TW200824258A - A control method for sensorless permanent magnet synchronous motor (PMSM) - Google Patents

Abstract

The invention provides a control method capable of assuring the synchronous start of at least two sensorless PMSMs by one inverter device, preventing oscillation generation during stable rated operation and low speed rotation, and controlling safe stop in case of failure. This synchronous start method provides for at least two sensorless permanent magnet synchronous motors (PMSM) which use a three-phase alternate power source as power. The three-phase alternate current with ultra-low frequency is temporarily applied to at least two PMSMs by one inverter device for a certain period to ensure that the motors can be synchronously started with low rotation, then their rotational speeds can be raised by gradually increasing the frequency of the power source to reach the rated rotation.

Description

200824258 IX. Description of the Invention: [Technical Field] The present invention is a control method of a permanent magnet synchronous motor (PMSM), which is a method for controlling a permanent magnet synchronous motor (hereinafter referred to as pMSM). Simultaneously start more than two non-inductive PMSMs, continuously run at a certain speed, and start from the reverse state, thereby preventing events such as vibrations caused by the rotation speed lower than the fixed speed, and also safely stopping when the fault occurs. The control method of the sensorless SpMSM for operation. [Prior Art] The known PMSM uses a three-phase alternating current as a power source, and employs an inductor (position detecting device) for detecting the position of the magnetic pole of the rotor, and the magnetic pole position of the rotor is detected by the inductor, corresponding to the detection. After the rotor pole position, the current is generated to a phase of the rotating coil of the foot coil, and the power is transmitted to the load starting mode by interaction with the magnetic field generated by the magnetic pole. It is similar to the PMSM and control circuit and conversion device of the inductive family. In addition to the total cost is higher than the induction motor represented by the AC motor, and the total cost of conversion, the sensor is also prone to problems, so it is used in A PMSM that requires a certain speed and a second condition can be used in this type of sensorless PMSM that does not require induction II and can be reduced to ^. In this type of sensorless pMSM, in order to make the control ship have the same function as the sensor, it is necessary to detect the various materials produced in the 抒 line to calculate the impurities and control it. The re-synchronization operation (for example, Japanese Unexamined Patent Publication No. Hei No. Hei No. Hei No. Hei. [Patent Document 1] Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. It is necessary to additionally install a special control device for starting, or to control the startup by a more complicated control method, in which the startup failure often occurs due to the control method of the complexity. In addition, each PMSM must have a conversion device for supplying power, so that the goal of cost reduction cannot be achieved. In the non-inductive PMSM synchronous starting method of the present invention, the solution is to apply the ultra-low frequency three-phase alternating current of a predetermined time by a single conversion device in the above two or more PMSMs, and start synchronously at a low speed, and then gradually Increasing the frequency of the power supply increases the speed to achieve a certain speed, and it is also possible to activate more than two PMSMs by a single conversion device. The present invention achieves a significant cost reduction by a simple control method and by using a single switching device, that is, two or more sensorless PMSMs can be controlled from the start of synchronous start to continuous operation. In addition, the effect of starting two or more sensorless PMSMs from the reverse state is also achieved. "In addition, it not only prevents the vibration generated when the rotation speed is lower than the constant speed rotation of the sensorless pMSM, but also achieves a stable and quiet low-speed operation. It can also detect the sensorless type. The abnormal rotation state caused by the failure of the PMSM or the like is controlled to achieve the effect of stopping the operation of the safety. [Embodiment] The synchronous startup method of the PMSM of the present invention has two or more The two-phase cross-current power source is powered. In the above two or more pMSMs, a three-phase alternating current of ultra-low frequency is applied for a predetermined time by a single conversion device, and after starting at a low speed synchronously, the power supply is gradually increased, and the rotation speed is increased. In order to reach 8 200824258, the speed of 'two sets of PMSMs can be synchronously started by a single conversion device or two or more of the three-phase coils of two or more PMSMs can be applied from the converter 2 Current, and by attracting the stator magnetic axis to attract: the rotor magnetic pole, while simultaneously synchronizing more than two PMSMs, then gradually improve the three-phase re-ship The frequency of the pressure can reach a certain speed and start synchronously. When the PMSM is reversed by external factors, two of the phases are connected in advance; the three-phase coil of the above PMSM is generated between the PMSMs. • The electric brake current allows all PMSMs to be synchronized in the reversed state and at the same speed, and the voltage and frequency generated by the PMSMm in the aforementioned synchronous speed are measured. The frequency converter is applied by applying the angular velocity of the rotational speed to the allowable angular velocity. / After the power supply is synchronized, the rotating magnetic field converted to the forward direction is used to lock the stop state, and a certain number of revolutions can be achieved and started synchronously. /, Not only can the synchronous output of the IGBT circuit of the converter be detected. The speed reduced by the PMSM of more than two parts, and the fresh and electric record generated during the operation of reducing the load torque state A. At the same time, the current phase of the converter provided by the ship is more than that generated by the PMSM. The voltage is greater than 15. With the phase of Λ, and by setting the angle greater than the internal phase difference, the two or more PMSMs will not vibrate when running. Steps, stalls and other phenomena.

Not only can the IGBT circuit of the conversion device detect the frequency, voltage, and current generated by the pMsM rotation speed, but also the igbt circuit can be used to detect the abnormally fresh voltage and current generated by the abnormal PMSM. The IGBT circuit is configured to generate a current of an abnormal frequency generated when the PMSM and the medium-portion of the two parts of the synchronous operation are synchronized from the synchronous speed to the asynchronous speed due to a failure, and the output of the switching device is blocked. And then safely stop a complete PMSM rotation.王9 200824258 [Embodiment 1] The so-called synchronous start method is a synchronous motor that uses a three-phase AC power supply as a power, as shown in Fig. 6, a synchronous motor G at the drive end and a synchronous motor driven at the drive end. It is set as a synchronous motor, and the two-phase terminals of the two motors are connected to each other in a stopped state, and each of them has an excitation current flowing in advance. When the start-up is started and the rotation is sufficiently connected to the drive D of the synchronous motor G, the synchronous motor g starts to rotate. The low-frequency current is supplied to the synchronous motor Μ, and the synchronous motor and the synchronous motor G are synchronized by the interaction with the magnetic field generated by the rotating magnetic field generated by the μ terminal of the synchronous motor and the exciting current, and the synchronization is accelerated. The speed at which the motor G end rotates continuously to increase the speed until the speed is increased to a high speed. The synchronous starting method, for example, can be used to start a power generating motor connected to a pump of a pumping station of a Yangshui power plant, or a large-capacity synchronous motor for starting a large-capacity turbine motor, and is not for the connected system. It will increase the load at startup, so it is highly recommended to be used for the startup mode that needs to be stabilized. As for each embodiment, it will be explained in detail one by one, and it will also be confirmed that various parameters affect the range of synchronous startup. Assuming the synchronous startup method is applied to the PMSM, there will be the following differences. Firstly, since the output power range of the PMSM is from 1 〇〇w to several kw, it is quite small compared to the general synchronous motor capacity. If the motor rotor has a private resistance value R range of 〇〇4 As for 2pu (4%~2〇%), it will be too large, and since the excitation is a permanent magnet, the excitation of pMSM is a fixed value and the power supply system uses IGBT (Insulated Gate Bipolar Tm^s=). The circuit and other key power supplies replace the synchronous ride g and so on. There are _ and other phenomena, from 10,000; its detailed turn is quite complicated, so from the clear parameters, the image will be compared with the /<parameters as a fresh calculation, and then calculated as the synchronous start range of 200824258. Or angular velocity ωι). And from the conversion device in the PMSM - (^ power. 1) 1C1 μ (using a conversion device to start a PMSM)

(a) Circuit and current Figure 1 shows the supply of a voltage from the power supply (converter) to the PMSM corresponding to the angular velocity cojO.Olorder. Although low speed assumes that VG is the voltage at constant speed rotation, Ig(a) is the constant speed rotation.

And f〇 is the fixed-speed rotation frequency, then Nlmin-i spine at very low speed: 'lb is: 呷 and voltage V v:=V〇· (f, / f0)= γ0. (ωι/ω〇) Where Lm represents the inductance corresponding to the motor reactance. ···〇 Since the circuit group anti-Zm cc^Lm is smaller than Rm, it is derived [Math 1]

Zrn —y~Rni2 + (wiLm)2 ; Rm The current I0(A) flowing to the circuit of Figure 1 is: V/Rm-V〇· (ωι/ω〇) · (1/Rm) In addition, if the resistance of the power supply is ignored Then, Rm becomes the electric ρ of PMSM and (b) the algorithm of torque (1) The FG generated when the motor rotates at a constant speed can be expressed by the following formula: 0.707 · Bmi · Αχ · Kw · cos δ [N/m2] ·* · (4; in the magnetic field lines generated by the permanent magnet, the maximum value of the basic wave magnetic field density [T] and 11 200824258 a!; using the motor coil to generate the external inductance, Αι=(Ι〇·Σζ)/(7Γ D) / (A / m) indicates (ΣΖ is the number of all series conductors of the three-phase coil, d is the internal diameter of the stator (m)) 'coil coefficient, (5; internal phase difference angle, and cos 5 and 1. If the value of the PMSM case applicable to hundreds of W grades is substituted into the above formula (4), the approximate value of F〇 can be calculated. F〇 and 0.707 · 0·3 · ΙΟ4· 1·〇·1·0=0· 212 · 104[N/m2] ~ (5 In addition, 'h can calculate the specific PMSM (200W and 150W output).

200w; single-phase resistance value Rm=7Q

150w; single-phase resistance value Rm=20Q Since the terminal voltage of the phase voltage of the above formula (3) is 200V, V〇=200/V3=l 15.5V "(6 to each 0^/0)0= 0.005, 0.01, 0·02, 0·03, 0.06 (pu) calculated I]. [Table 1] ωι/ω〇0.05 0.01 0.02 0.03 0.06 200W of L(A) 0.082 0.165 0.33 0.5 1.0 150W I! (A) 0.029 0.058 0.116 0.173 ----- 0.347 (II) Torque generated by 200W motor Since the constant-speed rotating current of the 200W motor is Ι〇=1·0 (Α), the surface area of the rotor is S=0.01 (m2), and the fixed speed is rotated Ν. Two 1300min-1, the rotor half after r=0.033m, so the overall force Fi of the PMSM and the generated torque T〇 can be calculated by the above formula (5).

Fi=F〇· (Ii/lO) · S[N] ^ T=Fi · r[Nm] 12 200824258 [Table 2] ωι/ω〇0.05 1 o.oi 0.02 0·03 0.06 Fi[Nl 1.74 — ^ 3.5 7.0 10.5 20.9 T[Nm] 0.06 0.11 023 034 0.69 (ni) The torque generated by the i5〇w motor is assumed to be a fixed-speed rotating current of 150W motor as ifOJIA), and the surface of the rotor is S-0.〇〇〇8 (m2), if the fixed speed rotates N〇=1300min-1, and the rotor half-grants r=0.0285m, Fi&t can still be calculated. [Table 3] α>ι/ω〇0.05 0.01 0.02 0.03 0.06 Fi[N] 0.703 1.4 2.81 4.19 8.41 T[Nm] 0.02 0.04 0.08 0.12 0.24 3) The energy and torque required for GD2 will produce a GD2 (kgm2) When the flywheel effect is rotated at a speed of N/min-1), the inherent energy E〇 is E〇=1.37 · GD2(N〇/100〇)2(kWS) =(1/730) · GD2 · N〇2 (WS or J) ... (8) GD2 makes the GD2 of the fan of the PMSM load larger than the PMSM, and can use the same thing for the 200W motor and the 150W motor. That is, GD2=0.124[kgm2] Therefore, Ε〇=(1/730) · 0·124 · 13002=287(WS or J) ...(9) 13 200824258 ωι/ω〇 The energy inherent to the speed E E=:E〇· (ωι/ω〇)2 (WS or J) (1〇) In addition, when three-phase current flows into the stator coil ((〇i/(〇g's low frequency) and produces - enough rotation In the case of a magnetic field, a force is generated between the Ns magnetic % adsorbed to the surface of the rotor by the magnetic field, and if the initial N and s poles are not synchronized, synchronization cannot be performed. Assuming that the rotor magnetic pole has eight magnetic poles, each Mechanical angle of a magnetic pole

T 0i=2Tr/8=〇.785[md] (1)) Assuming that the torque required to rotate the rotor is Tm, the required energy w W=Tm [Nm or J]=〇.785 · Tm Formula (10) = Formula (12), then... (13) ... (14) and the generated torque obtained by (II) W = 287 . (α^/ωο) 2 〇 · 785 · Tm Therefore, Tm = 365 .(α^/ωο)2 Tm required for 200W motor comparison

[Table 4] ---—^—_ ωι/ω〇0.005 0.01 0.02 0.03 0.06 _0·009 0.0365 0·146 0329 L314 0.06 0.11 0.23 0.34 0.69 From this calculation result, if the value of (ωι/ω()) is smaller than The speed below 〇〇3pu (ie 3%) will be synchronized, and if it is greater than this value, it is more difficult to synchronize. Similarly, calculate a 150W motor. 14 200824258 [Table 5] ωι/ω〇0.005 0.01 — 0.02 0.03 0.06 Tm[Nm] 0.009 _〇i)365 0.146 0.329 1.314 T『Nm】 0.02 0.04 ------ 0.08 0.12 0.24 From the calculation results, Even if the value of (ωι/ω{)) is equal to 〇.〇lpu (ie, ι%), the speed is difficult to synchronize. 4) Synchronous start condition φ From the calculation results, the so-called synchronous start condition is based on the PMSM applying a certain low frequency (corresponding to the call) voltage from the power supply, and then supplying the current through the flow. The torque and energy to the PMSM contain GD2 for a certain period of time, and accelerate to reach the required rotor energy, and can be fully supplied. In the above-mentioned 200-motor, it is possible to synchronize the call within less than 0.03 pu (ie 3%) and fix ωι ’ in advance. In addition, if the ωι of the 150W motor is less than 〇 ) 11) 11 (that is, 1%), it is more difficult to reduce the synchronization of the program. Therefore, the voyage can be stably started by increasing the power supply voltage V. In the case where the above embodiment is a brother of 1C1M (one PMSM is activated by one conversion device) or 1CXM (two pmsm is activated by the two conversion devices), it is necessary to further add the synchronization problem between the X portions. If the activation method of 1) to 4) above is used, the PMSM does not need an inductor (for the sensor type), or in a low frequency state (less than a few %, mainly less than 3%) and a fixed time in a few seconds PMSM applies the output frequency voltage and current of the three-phase dedicated conversion device. Even for the two or more PMSMs shown, the power supply can be synchronized, and by increasing the power frequency of the conversion device, the synchronization speed can be maintained continuously. The fixed speed rotation. 15 200824258 [Embodiment 2] Next, the synchronous starting method in the second embodiment will be described. In the two-phase coil shown in Figure 3, 'the first direct current flows to the two-phase coil (in Figure 3, the resulting stator magnetic axis (stop rotation) attracts the rotor magnetic pole and the magnetic axis is the same as +; The phase switching of the general conversion device between VW and WU continues: increase the frequency. In this case, it takes several seconds for the magnetic axis to match the initial magnetic pole. ^ The predetermined time At (the rotor is vibrated by fixed vibration, while Synchronization until stable) _ 目目 indicates the -part PMSM, if this method is used to start PMSM with more than two platforms, more or less will limit the synchronization conditions, but by reviewing PMSM The resistance value, GD2, applied voltage, etc. can be surely achieved. It is determined by selecting the synchronous start method of the first and second embodiments or by reviewing the control method and the balance of the number of motor parts. If the pMSM is started by 1CXM (starting the crotch with one conversion device), the motor resistance value of the PMSM is the most important factor that can be activated at the same time, and the GD affects the power supply voltage. In other words, if the two resistors are to be activated at the same time, the resistance values are negligible, and the voltage and frequency (low voltage, low frequency) supplied by the converter and the starting current can be obtained by having sufficient holding time. (synchronized current) flows into the PMSM. If it is two cases, the focus is on starting two parts at the same time and at the same time. If the synchronization can be fully implemented, then the process of the power frequency and the PMSM speed is gradually increased. In this way, it is possible to operate in synchronization with each other and to accelerate more slowly. This acceleration process and the operation control after reaching the constant speed rotation will be converted into stable operation by controlling the closed loop by detecting the voltage and frequency of the pMSM. With a single conversion device, it is possible to activate more than two PMSMs, thereby greatly reducing the overall PMSM cost including no sensors. 16 200824258 [Embodiment 3] i-sensory PMSM is used for, for example, larger air conditioners, etc. In the environment, the load connected to the PMSM in series is an electric fan, in order to stop a certain PMSM device (two or more driven by a single conversion device)]]8]^) Once ·: · Turn off the power, it will be affected by the airway pressure loop formed by other running electric fans, apply pressure to the stopped electric fan, and rotate in the general reverse reversal. In some cases, the startup method disclosed in the present invention can be used to synchronize a single conversion power supply even in the case of a PMSM with no sensor or more. And stable start.

If the two electric fans are separate power supplies (the conversion devices used by each), rotate at different speeds (for example, one is -Nsmin-1 and the other is _N4min-i), and when it is 1C1M, ' It is necessary to connect the coils of the two pmsm phases in advance, and then use the current between the two PMSMs generated by the /watt to reverse to generate the power generation brake, and rotate the two PMSMs to the same speed of the intermediate-N5min-1. Let the two PMSMs remain in sync, that is, in a PMSM, the state of the rain-part PMSM can be determined. • In this state, the voltage and frequency generated from the PMSM are detected, and the speed is accelerated to _N5min-1 (reverse) by applying a corresponding voltage from the IGBT to simultaneously synchronize the two PMSMs. Omkf1 (stop) ~ Nomin · 1 (fixed speed rotation). For further details, in the case of two PMSMs (8) and (b) (1C2M), and the output terminals of the IGBT circuit, the three-phase terminals of pmsm must be connected in advance. Therefore, in order to stop the device for any reason, if the output of the IGBT circuit is interrupted, the PMSM (8) (b) becomes Nomin, constant speed rotation) ~ Omin · 1 (stop) ~ reverse, but due to the two motors For the electrical connection, so 17 200824258 makes the reverse I铋; the brother can also maintain the synchronization state and rotate at the same speed. If the two PMSMs are non-connected and operate separately, the PMSM(a)(b) will each have a different speed of -Ngmin·1, - Rotation, but if there is an electrical connection, the brake current is generated due to the mud, so the electric brake torque is generated and the synchronous operation can be performed with the -Nsmin·1 rotation speed in the middle of Is^min 1. Therefore, the voltage and frequency generated by the PMSM at this time can be detected from the electric disk (PMSM is used as a generator) and the conversion device is applied with a three-phase voltage and frequency corresponding to a voltage of 5V, and the flow is predetermined. The current causes the power source to be synchronized, and then one of the % sources is switched and then moved to the Omirf1 state by turning into a positive rotating magnetic field. In the above program, the PMSM without sensor can be started from the reverse state. Its maximum feature is not limited to one PMSM, but can also be used for the synchronization of the PMSM 复 'inverse 4r of the complex part, which is similar to the synchronization phenomenon at startup. As shown in Figure 4, when rotating in the clockwise direction, the reverse direction is in the counterclockwise direction. When the PMSM is two, it will synchronize as described above and generate a reversal magnetic field with a rotation of -Nsmm, so it is excited. The frequency of the stator coil & is f5=PN5/120 (Hz) (P is the number of magnetic poles), where co5==2f5, & for the angular velocity obtained by the frequency detected by the coil terminal, it can be judged 'If it is a reverse magnetic field and is located in the range of angular velocity % soil (〇,) as a power source applied from the conversion device, it can be synchronized. Where % is the synchronized allowable angular velocity. In fact, it is important to apply -^ soil fine (four) (10) angular velocity will be more 18 200824258 easy and indeed synchronized. By applying a voltage, of course, the voltage of the current required is exceeded. Reference is made to the vector of Figure 5. y, Fig. 4 (b) shows the direction of the current of the reverse magnetic field outputted by the switching device generated during synchronization. Therefore, immediately after synchronization, V and w are switched to the forward magnetic field by switching to Figure 4 (C), and the _ speed is changed from _N5min to G-·!. Even if the 4th part of the _ _ _ can be expected to JL do the above procedure. The boot will apply to the synchronous boot method described in 1). [Embodiment 4] Φ In the present embodiment, a method for stabilizing the control when the rotation is less than 70% of the constant speed will be described. When the speed is less than the fixed speed, especially for the load such as the electric fan, the load torque will drop by 16 in this quadratic speed. Therefore, the current necessary as ρΜ_ will also gradually decrease in proportion to the torque. If the internal Xiangxiang difference angle 5 of the pMSM is reduced, if the *1CXM condition and two or more PMSMs are connected to one of the conversion powers, the current value state will be greatly reduced to cause the negative load characteristics of the respective electric fans to be different. The internal phase difference angle is different from the vibration generated, and the phenomenon that the rust is not stable is caused. So you can use the conversion device to turn the coffee ^ (10)

Bipolar Transistor) The output of the circuit detects more than two PMSMH fresh and current values during synchronous operation, and allows the current supplied from the switching device to lead the voltage 15 more than the PMSM. In the above, by increasing the internal phase difference angle (5 to increase the current, there will be no vibration, non-synchronization, stall, etc., and more than two PMSMs will be operated.) At constant speed rotation (fixed speed rotation speed) In order to make the PMSM produce the most efficient operation, the metropolis will use the direct current ld = 0 to control (the control motor generates the same phase of the private voltage and current). In this case, since the current is the minimum value, When two or more PMSMs are running, as described above, when the speed is reduced, the speed of the engine is increased. 19 200824258 =: The possibility of raising or not synchronizing. In order to improve this phenomenon, if the voltage is generated before the heart, the internal phase is increased to The loss is equal to F. Because the electric button is also increased, (4) the two PMSMs (in the case of the second part) generated by the difference in the load characteristics of the C ife * ^ load can be controlled to control the vibration or non-synchronization. phenomenon. Phase angle. If the above is better than 2G° or more, the effect of stable control can be expected [Embodiment 5]

In the embodiment, the method of stopping the PMSM safely can be performed. The IGBT circuit of the conversion device can detect the voltage and current corresponding to the frequency generated by the PMSM rotation speed, and can also detect the 'PM' of the two or more PMSMs in the step operation. Because the fault and other factors generate different frequency currents from the same speed, the rotation speed is reduced, and the output of the farm is interrupted, and the rotation of another pMsM can be safely interrupted. For example, when two PMSMs are running, if one of them stops from the synchronous speed stall and stops reducing the rotation speed due to factors such as bearing damage, the pMSM will generate a frequency voltage corresponding to the rotation speed, and the current is converted. The device and the other generated different frequency currents, so igbt can be used to detect this current, and the output of the interrupting device can also be safely stopped. In addition, if one of the aforementioned malfunctioning motors can be interrupted early, the current flowing through the IGBT circuit is large, so it can be stopped by the OCR (Over Current Relay) circuit. [Industrial Applicability] The control method of the present invention is widely used in the case of two or more sensorless types because of its high reliability and easy construction, and the advantages of low cost. 20 200824258 [Simple diagram of the diagram] FIG. 1 is an equivalent circuit embodiment when starting up in 1C1M. FIG. 2 is a circuit embodiment in 1CXM. FIG. 3 is a schematic diagram of the second embodiment of the synchronous starting method. Figure 5 is a voltage vector diagram applied to the reversal. Figure 6 Schematic diagram of the synchronous start mode

21 200824258 [Description of main component symbols] Power supply (彳 > 六一夕) Power supply (conversion device) PMSM (乇夕夕) PMSM (motor)

twenty two

Claims (1)

200824258 X. Patent application scope: 1. Synchronous starting method of the type sensor permanent magnet synchronous motor (PMSM), which has two or more non-inductor permanent magnet synchronous motors powered by three-phase AC power, The utility model is characterized in that the above two or more pMSM*s are driven by a single conversion device to apply an ultra-low frequency three-phase alternating current of a predetermined time at a low speed, and then gradually increase the frequency of the power source to increase the rotation speed, thereby achieving a certain rotation speed. 2. The non-inductive permanent magnet synchronous motor according to the scope of the patent application of the present invention, wherein the towel is applied to a coil of any two of the three-phase coils of the two or more PMSMs, and a DC is applied from the switching device. The current, and by generating the magnetic axis of the foot to attract the rotor magnetic pole to synchronize the two or more PMSMs simultaneously, and then gradually increase the frequency of the three-phase AC voltage, a certain speed can be achieved. 3. The synchronous starting method of the non-inductive permanent magnet synchronous motor according to claim 1, wherein three or more pMSM three-phase coils are connected between the phases, and an electrical brake is generated between the PMSMs. The current allows all PMSMs to be synchronized at the same speed in the reverse state, and detects the voltage and frequency generated by the PMSM in the aforementioned synchronous speed, and from the switching device, the frequency voltage at which the angular velocity of the rotational speed is applied, After the current is synchronized with the source, the rotating magnetic field converted to the forward direction is used to lock the stop state, and a certain number of revolutions can be achieved in the reverse state. 4. According to the synchronous start method of the sensorless permanent magnet synchronous motor described in the first paragraph of the patent application, in which the output of the IGBT (Insulated Gate Bipolar Transistor) circuit of the conversion device can be used to detect two parts in synchronous operation. The above-mentioned PMSM reduces the speed, and the voltage, frequency and current value generated when the load torque is reduced, and the current phase provided by the 23200824258 by the strain converter is advanced compared with the voltage generated by the aforementioned pjyjSM. A phase greater than 15 or more, and by setting an angle greater than the internal phase difference, the two or more PMSMs can be operated without vibration, non-synchronization, and stall. 5. According to the synchronous start method of the sensorless permanent magnet synchronous motor described in the first paragraph of the patent application scope, the frequency and voltage corresponding to the PMS1V can be measured not only by the leg circuit of the conversion device but also by the speed of the motor. At the same time, the IGBT circuit is used to detect the different suspension frequency <voltage, current' generated by the pMSM that generates the abnormality, and the above-mentioned excitation detection is used to make one of the two or more PMSMs in the synchronous operation change from the synchronous speed. = Synchronize the abnormally fresh Wei when the speed is low, and cut off the output of the device before the interruption, so that it can be safely stopped - the complete PMSM turn _ 24