JP3284201B2 - Sensorless brushless motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a permanent magnet rotor, a three-phase stator winding, a three-phase inverter, a rotational position detecting circuit, a microcomputer, and a commutation control circuit. The synchronous motor operates by repeatedly outputting the drive reference signal at the time of starting the inverter irrespective of the rotation position of the magnet rotor, and after startup, the microcomputer sends a signal corresponding to the rotation position of the permanent magnet rotor from the rotation position detection circuit. A sensorless brushless motor that performs a sensorless brushless motor operation by inputting and calculating and outputting an inverter driving reference signal. Specifically, a three-phase inverter detects a harmonic detection voltage three times the fundamental wave of the motor induced voltage. By not being proportional to the voltage of the DC power supply and by always stabilizing it, start-up failure, rotor reversal, Motor switching out of synchronization, and the frequency of switching from synchronous motor operation to sensorless brushless operation has been significantly reduced compared to before, so that the synchronous motor operation time (= start-up time) has been improved. The present invention relates to a sensorless brushless motor.

[0002]

2. Description of the Related Art FIG. 13 shows a conventional sensorless brushless motor manufactured by the present applicant (Japanese Patent Laid-Open No. 62-18999).
No. 2, JP-A-62-189993). As shown in FIG. 13 (a), a permanent magnet rotor 1 and three stator windings 21, 22, 23 are Y-connected. The transistor groups U +, V +, W +, U−, V−, W− are supplied with power from the three-phase stator winding 2 and the DC power supply 7 and by a commutation control signal.
A three-phase inverter 3 for controlling the commutation of the three-phase stator winding 2 by outputting an AC voltage to the output lines 31, 32, 33 by controlling the ON / OFF of the A commutation control circuit 4 for outputting a control signal, and three resistance wires 51, 52, 53 are connected in parallel with the three-phase stator winding 2 in a Y-connection. A neutral point terminal has a three-phase resistor 5a connected to the non-neutral point terminal 2 of the three stator windings 21, 22, 23, and a neutral point of the three-phase stator winding 2 potential e ₁ and three-phase resistors 5a of neutral point e ₂ and the stator windings 21 by entering from the deviation of the potential,
Detecting an induced voltage of 22 and 23 have a differential amplifier 5b outputs the desired rotational position signal e ₃ corresponding only to the three-fold harmonic of the fundamental wave corresponding to the predetermined rotational position of the permanent magnet rotor 1. And a microcomputer 6 interposed between the rotational position detecting circuit 5 and the commutation control circuit 4. As shown in FIGS. 13B and 13C, the microcomputer 6 includes a signal group m ₂ of a pattern sequence of six types of two-phase excitation signals whose phase sequentially changes by 60 degrees in the rotation direction. it has been, and an inverter startup drive reference signal for performing two-phase excitation at startup, and the signal group m ₂ is written to the interior of the ROM61 to inverter drive reference signal for performing two-phase excitation after activation Te, startup repeatedly outputs the signal group m ₂ as will accelerate progressively pattern repetition period until a predetermined short period to the commutation control circuit 4, after starting to enter the rotational position signal e ₃ The pattern repetition period is calculated for each period as required, and a rotation speed corresponding signal e ₄ corresponding to the rotation speed of the permanent magnet rotor 1 is output to the commutation control circuit 4. Faith No. together with e ₄ is configured to repeatedly output the signal group m ₂ as an inverter driving reference signal. Commutation control circuit 4, a limiter circuit 41 and the pulse width modulation unit provided with a (PWM) 42 and the comparator 43, the limiter circuit 41, the internal current limiter value control signal e ₇ to be output from the microcomputer 6 during startup And a voltage signal e ₉ proportional to the current flowing through the transistor from the current detection resistor 3 a of the three-phase inverter 3 at the time of starting and after the starting, and turned on from the pulse width modulation unit (PWM) 42. An off signal is input, and a pulse width modulated on / off signal input from a pulse width modulator (PWM) 42 is operated.
Outputs a commutation control signal e ₆ such that the current limiter value is "low" when the stop signal e ₈ a current limiter value control signal e ₇ enters the halt signal is "0", and the operation-stop signal e ₈ is an operation signal, and when the current limiter value control signal e ₇ becomes “1”, the commutation control signal e ₆ is output so that the current limiter value becomes “high level”, and the voltage signal e ₉ becomes higher than the limiter value. Then, the commutation control signal e is set so that all the transistors of the three-phase inverter 3 are turned off.
₆ is output controlled. The pulse width modulator (PWM) 42 receives the signal m ₂ output from the microcomputer 6. The comparator 43 inputs the speed instruction e ₅ from the outside, eliminating the deviation between the rotational speed corresponding signal e ₄ and the speed command e ₅ by inputting the rotational speed corresponding signal e ₄ to be output from the microcomputer 6 after activation Thus, a code (either plus or minus) for determining the increase / decrease direction of the pulse width modulation in the pulse width modulation unit 42 is output to the pulse width modulation unit 42. In this configuration, the ground of the DC power supply circuit 54 for detection of the differential amplifier 5b and the ground of the DC power supply 7 of the three-phase inverter 3 are common. According to the sensorless brushless motor having the above configuration, the inverter of the pulse width modulation method can be used, but the power transistor, the reactor, the capacitor, etc. used in the past are unnecessary, small, and inexpensive.
The time delay of the rotation position detection circuit can be reduced.

FIG. 14 shows a timing chart. FIG.
Each signal of FIGS. 14A to 14Q will be described with reference to FIG. (A) is a basic clock of the microcomputer 6, (b) is an operation input to the microcomputer 6
The stop signal e ₈ , (c) is a current limiter value control signal e ₇ output from the microcomputer 6 to the commutation control circuit 4,
(D) is a signal group m ₂ output from the microcomputer 6 to the pulse width modulator (PWM) 42 of the commutation control circuit 4, and the rising and falling edges of the second signal group m ₂ are the microcomputer Is a step switching timing signal which is a basis for generating an output voltage waveform of the three-phase inverter. (E) is a waveform which is a deviation between induced voltages e ₁ and e ₂ inputted to two input terminals of the differential amplifier 5b. The induced voltage detection signal before shaping, (f) shows the rotational position signals e ₃ , (g) and (h) after the waveform is shaped by detecting a harmonic three times the fundamental wave in the induced voltage by the differential amplifier 5b. ) And (i)
And (j) relate to any one of the three stator windings 21, 22, 23, and (g) shows the motor in a state where the transistor group of the three-phase inverter 3 is not turned on / off. There induced voltage that occurs in the stator windings of one phase when rotating, and (h) (i) some of the commutation control signal e ₆ (three-phase inverter 3 of one phase of the transistors U + and U- , V + and V−, or W + and W−, a pair of commutation control signals e ₆ ) and (j) are pulse width modulated inverter output voltages applied to a one-phase stator winding, (K) indicates the current limiter value of the limiter circuit 41, and (q) indicates the rotation speed of the permanent magnet rotor.

[0004]

According to the above-described sensorless brushless motor, the DC power supply circuit 54 for detection of the differential amplifier 5b and the DC power supply 7 of the three-phase inverter 3 share the ground 58. Yes, differential amplifier 5b
Is proportional to the voltage of the DC power supply 7 of the three-phase inverter 3, the voltage dividing resistors 55a to 55h are provided to divide the neutral point of the motor and the motor terminal voltages U, V, W to divide the DC power supply 7 Although the input voltage of the differential amplifier 5b does not exceed the voltage of the DC power supply circuit 54 for detection at a high voltage (so that the differential amplifier 5b is not destroyed by the high voltage),
If the voltage of the DC power supply 7 of the three-phase inverter 3 fluctuates to a minimum value, the voltage dividing ratio by the voltage dividing resistors 55a to 55h becomes too large, and a harmonic detection voltage (differential amplifier) three times the fundamental wave of the motor induced voltage. since the input voltage of 5b) is too low, the value of the rotational position signal e ₃ becomes unstable, uncertain, it was found that there is a problem that leads to starting failure rotor reverse rotor desynchronization.

Further, according to the sensorless brushless motor having the above-described structure, when the load is largely changed, the permanent magnet rotor 1 may be vibrated when the permanent magnet rotor 1 is positioned by initial excitation. If the operation is shifted to the synchronous motor operation before the vibration subsides, the rotation of the rotating magnetic field and the permanent magnet rotor 1 is lost due to the influence of the vibration of the permanent magnet rotor 1 and the operation cannot be switched to the brushless synchronous motor operation. It has been found that the permanent magnet rotor 1 may fail due to vibration or may be reversed due to vibration, and the same unstable phenomenon as described above may also occur during the operation of the synchronous motor. For this reason, the initial excitation time is the same as that of the permanent magnet rotor 1.
It is necessary to continue the vibration until the vibration stops, and since the vibration of the permanent magnet rotor changes depending on the load, there is a problem that the initial excitation time must be lengthened when the load is large.

Furthermore, according to the sensorless brushless motor having the above configuration, after entering a stop signal e _8, immediately and try to restart the synchronous motor operation can not be positioned in the permanent magnet rotor 1 even if the initial excitation The synchronization between the rotating magnetic field and the permanent magnet rotor 1 is lost,
For this reason, the possibility of failure in switching from the synchronous motor operation to the sensorless brushless motor operation and the reverse rotation phenomenon of the permanent magnet rotor 1 increase. For this reason, conventionally, a predetermined time after the input of the stop signal, specifically, 0.5 seconds, is set as the restart prohibition time, and when the operation signal is input within the restart prohibition time, the restart is performed. Initial excitation after prohibition time elapses
The motor is restarted in the order of synchronous motor operation-sensorless brushless operation. However, under use conditions in which the load inertia is larger than a predetermined value or the rotation speed of the permanent magnet rotor 1 is higher than the predetermined value, the permanent magnet rotation does not occur even after the restart prohibition time of 0.5 seconds has elapsed. If the operation signal is input immediately after the stop signal is input so that the rotation of the child 1 does not stop, the switching from the synchronous motor operation to the sensorless brushless motor operation fails or the permanent magnet rotor 1 There is a possibility such as a reversal phenomenon. In order to solve such a problem, the restart prohibition time is extremely long, such as 6 seconds, under the use condition in which the load inertia is larger than a predetermined value or the rotation speed of the permanent magnet rotor 1 is higher than a predetermined value. Had to be set. However, when the restart prohibition time is set to be long, it has been found that even if the rotation of the permanent magnet rotor 1 is actually stopped, a problem occurs that the restart cannot be performed until the restart prohibition time has elapsed.

According to the present invention, even when the voltage of the DC power supply of the three-phase inverter is higher than the input voltage of the differential amplifier, the harmonic detection voltage three times the fundamental wave of the induced voltage is set to a required value larger than the conventional value. As a result, it is possible to stabilize the motor, thereby avoiding startup failure, rotor reversal, and rotor loss of synchronism. In addition, the frequency of switching from synchronous motor operation to sensorless brushless operation can be made lower than before so that synchronous motor operation time (= It is an object of the present invention to provide a sensorless brushless motor capable of shortening a start-up time, and more preferably, when a stop signal is input and the operation is to be resumed immediately (during stopless brushless operation), restart is prohibited. Omits time, initial excitation, and synchronous motor operation, and stops sensorless brushless operation without completely stopping the rotation of the permanent magnet rotor. It can be restarted suddenly, and it can be divided into the stop brushless operation and the restart inhibition time compared to the conventional restart inhibition time, and the restart inhibition time can be greatly shortened. It is an object of the present invention to provide an embodiment in which the operation can be resumed immediately after a lapse of a very short time even when the operation is to be resumed after a lapse of time.

[0008]

According to the present invention, there is provided a three-phase stator in which a permanent magnet rotor 1 and three stator windings 21, 22, 23 are Y-connected. And a transistor group U +, V +, W +, U-, V-, W
Is turned on / off as required to output lines 31, 32, 33
A three-phase inverter 3 that outputs an AC voltage to control the commutation of the three-phase stator winding 2, a commutation control circuit 4 that outputs a commutation control signal to the three-phase inverter 3, The three resistance wires 51, 52, 53 are Y-connected in parallel with the child winding 2, and the non-neutral point terminals of the resistance wires 51, 52, 53 are connected to the three stator windings 21, 22. , 23 and the three-phase resistor 5a connected to the non-neutral point side terminal 2, and inputs the potential e1 of the neutral point of the three-phase stator winding 2 and the neutral point e2 of the three-phase resistor 5a. The stator winding 2 from the potential deviation
The permanent magnet rotor 1 is detected by detecting induced voltages of 1, 22, and 23.
Differential amplifier 5 which outputs a required rotational position signal e3 corresponding only to the third harmonic of the fundamental wave corresponding to the predetermined rotational position
b, and a microcomputer 6 interposed between the rotational position detection circuit 5 and the commutation control circuit 4. A signal group that is used as a drive reference signal at the time of starting the inverter for performing three-phase excitation or two-phase excitation, and is used as an inverter drive reference signal after the start is written in the internal ROM 61. All or a part of the signal group is repeatedly output to the commutation control circuit 4 so as to gradually increase the speed until the rotation is started, and after the start, the rotation position signal e3 is input to make the pattern repetition cycle necessary for each cycle. the combined operation on each cycle is configured to repeatedly output all or part of the signal group, and the rotational position detecting circuit 5, the detection of the differential amplifier 5b The DC power supply circuit 54 includes two DC power supplies 54a and 54b connected in series, and a point between the DC power supplies 54a and 54b and a neutral point of the three-phase stator winding 2 are detected. Of the primary side element 55 and the secondary side element 56 which are electrically insulated from each other, and the rotational position signal e3 output from the differential amplifier 5b is supplied to the primary side element 55 so as to flow therethrough. The present invention provides a sensorless brushless motor having an insulated signal output conversion circuit 5c for outputting a rotational position signal e3 induced in the secondary element 56.

[0009]

When the operation signal is input, the microcomputer 6 repeatedly outputs the first signal group m ₁ (or the second signal group m ₂ ) to the commutation control circuit 4 as a drive reference signal at the time of starting the inverter. The commutation control circuit 4 outputs a commutation control signal e ₆ corresponding to the drive reference signal m ₁ (m ₂ ) at the time of starting the inverter.
Is output to the three-phase inverter 3. The three-phase inverter 3
The commutation control signal e ₆ from the commutation control circuit 4 is input, and the transistor groups U +, V +, W +, U−, V−, and W− are controlled as required to turn on and off. Two
Outputs three-phase (or two-phase) AC voltage. An initial exciting current flows through the three-phase stator winding 2 to dampen the permanent magnet rotor 1, and then an exciting current flows to generate a rotating magnetic field, and the permanent magnet rotor 1 is synchronized with the rotating magnetic field. Starts rotating. In the above case, the drive reference signal m ₁ (m ₂ ) at the time of starting the inverter drives the permanent magnet rotor 1 synchronous motor by advancing the step angle by thirty degrees (sixty degrees) every time one pattern is output. become. Then, the microcomputer 6 sets the first signal group m ₁ (or the second signal group m ₂ )
The drive reference signal m ₁ (m ₂ ) at the time of starting the inverter is output to the commutation control circuit 4 so that the pattern repetition period of the inverter gradually increases, whereby the permanent magnet rotor 1 is gradually accelerated, and the permanent magnet When the rotor 1 outputs the pattern repetition cycle at a predetermined short cycle so as to increase to a predetermined rotation number, the synchronous motor drive ends.

After the start, the microcomputer 6 inputs the rotation position signal e ₃ from the rotation position detection circuit 5, calculates a pattern repetition period, and sets a signal group m ₂ according to the period.
Is repeatedly output to the commutation control circuit 4 as an inverter drive reference signal. The commutation control circuit 4 outputs a commutation control signal e ₆ corresponding to the inverter drive reference signal m ₂ to the three-phase inverter 3. At this time, the three-phase inverter 3 makes one rotation of the electric angle of the permanent magnet rotor 1. internal transistors U + enter six-fold of the second signal group m ₂ of the two-phase excitation resulting commutation per, V +, W +, U- , V-, · on the W- off control and output lines 31, 32, and 33 output AC voltages of two-phase excitation. Therefore, the induction current of the two-phase excitation causes six commutations per one rotation of the electrical angle in the three-phase stator winding 2 to generate a rotating magnetic field, and the phase of the induction voltage of the three-phase stator winding 2 is changed. Sensorless brushless motor drive is performed by matching the phases of the output voltages of the three-phase inverter 3 to obtain an electric power equivalent to a DC motor.
Mechanical energy conversion is performed, and thus the permanent magnet rotor 1 rotates in synchronization with the rotating magnetic field, and the permanent magnet rotor 1
Is accelerated to a predetermined rotation speed.

In the above case, since the ground 54c of the DC power supply circuit 54 for detection of the differential amplifier 5b is separated from the ground of the three-phase inverter 3, the input voltage of the differential amplifier 5b The amplitude of the higher harmonic detection voltage (the deviation of the voltage between the input terminals + and-of the differential amplifier 5b) three times the motor induced voltage can be obtained irrespective of the fluctuation of the voltage of the power supply 7, much larger than in the past. . Then, the rotational position signal e ₃ output from the differential amplifier 5b flows to the primary element 55 of the insulation type signal output conversion circuit 5c, and the secondary element 56 sends the rotational position signal e ₃ to the microcomputer 6.
₃ even if the voltage of the DC power supply 7 of the three-phase inverter 3 fluctuates to a minimum value, the rotational position signal e output from the secondary element 56 and input to the microcomputer 6
₃ is a sufficiently reliable electrical magnitude rotation position signal e that prevents the microcomputer 6 from malfunctioning at the stage when the rotor rotation speed is much lower than before and the rotor speed is much lower than before. ₃ is obtained. Accordingly, the conventional problems of starting failure, rotor reverse rotation, and rotor step-out can be eliminated, and the frequency of switching from synchronous motor operation to sensorless brushless operation can be reduced as compared with before, so that synchronous motor operation time (= startup) Time).

When a stop signal is input during operation, the microcomputer 6 reads the inverter drive reference signal m ₂ from the ROM 61 and thereafter reads the commutation control circuit 4.
Stop repeatedly outputting to. Therefore, the three-phase inverter 3 does not receive the commutation control signal e ₆ corresponding to the inverter drive reference signal m ₂ from the commutation control circuit 4, so that the two-phase excitation AC voltage is output from the output lines 31, 32 and 33. The output stops, the rotating magnetic field of the three-phase stator winding 2 is demagnetized, and the rotation speed of the permanent magnet rotor 1 decreases.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a sensorless brushless motor according to the present invention will be described below with reference to the drawings. 1 to 6 show a first embodiment. As shown in the block circuit of FIG. 1A, the sensorless brushless motor of this embodiment has a shape in which the magnetic flux distribution in the gap with the stator during steady rotation includes harmonics of three times the fundamental wave. Permanent magnet rotor (rotor) 1 and three stator windings 21, 22, 23
Are connected so as to be supplied with power from the DC power supply 7 and three output lines 31, 32, 33 are connected to the three-phase stator winding 2. Transistor groups U +, V +, W which are connected in parallel to the non-neutral point terminals of the stator windings 21, 22, 23 and have a required arrangement by a commutation control signal (pulse width modulated commutation control signal).
+, U-, V-, and W- are on / off controlled to convert DC to AC, output from output lines 31, 32, and 33, and feed three-phase stator winding 2 to control commutation. Three-phase inverter 3
If the performed the required pulse width modulated input current limiter value control signal e ₇ and the rotation speed corresponding signal e ₄ a first signal group m ₁ or the second signal group m ₂ from the microcomputer 6 to a required order A commutation control circuit 4 of a pulse width modulation type for outputting a commutation control signal e ₆ to the three-phase inverter 3, and three resistance wires 51, 52, 5 in parallel with the three-phase stator winding 2.
A three-phase resistor 3 is Y-connected and the non-neutral terminal of each resistance wire 51, 52, 53 is connected to the non-neutral terminal 2 of the three stator windings 21, 22, 23. three-phase stator winding voltage e ₁ of the neutral point of 2 and three-phase resistors 5a of neutral point e ₂ and the stator windings 21 and 22 enter from the deviation of the potential which has a vessel 5a, by detecting the induced voltage of 23 further comprising a differential amplifier 5b for outputting a required rotational position signal e ₃ corresponding only to the three-fold harmonic of the fundamental wave corresponding to the predetermined rotational position of the permanent magnet rotor 1 The DC power supplies 54a and 54b of the differential amplifier 5b are connected to the neutral point of the three-phase stator winding 2, and the primary element 55 and the secondary element 56 are electrically insulated. And a rotational position output from the differential amplifier 5b to the primary side element 55. Flowing a No. e ₃ the secondary element 56
The rotational position signal e ₃ induced in the microcomputer 6
A rotational position detecting circuit 5 adapted to output to the inverter, and an inverter interposed between the rotational position detecting circuit 5 and the commutation control circuit 4 for performing two-to-three-phase excitation at the time of start-up. second signal group m ₂ is written to the interior of the ROM61 to the first inverter driving reference signal signal group m ₁ and after startup of the drive reference signal, a predetermined short period of pattern repetition period at startup The first signal group m ₁ is repeatedly output to the commutation control circuit 4 so as to gradually increase the speed to the commutation control circuit 4. After the start, the rotation position signal e ₃ output from the rotation position detection circuit 5 is input and the pattern is input. the repetition period being adapted repeatedly outputs the second signal group m ₂ combined by calculating the required in each cycle to each period,
Therefore, by stabilizing the harmonic detection voltage three times the fundamental wave of the motor induced voltage so as not to be proportional to the voltage of the DC power supply of the three-phase inverter, and always stabilizing it, leading to startup failure, rotor reversal, and rotor loss of synchronization. Can be avoided, the switching frequency from synchronous motor operation to sensorless brushless operation can be greatly reduced compared to before, and the synchronous motor operation time (= start time) can be shortened. Also, when the load inertia is large or the load fluctuates. Has a stable start-up characteristic and a short start-up time. Further, the harmonic detection voltage three times the fundamental wave of the motor induced voltage becomes constant without being affected by the level of the inverter DC power supply voltage, and the rotational position detection circuit 5 and can be output stable rotational position signal e ₃ you can avoid reversing out-of startup failure and rotor, and also enter the stop signal When the operation is to be resumed immediately, the sensorless brushless operation can be restarted without completely stopping the rotation of the permanent magnet rotor. Even after a short time and the stop brushless operation time elapses, the operation can be resumed immediately when the operation is to be resumed.

The rotational position detecting circuit 5 includes three resistance wires 5
1,52,53 and a three-phase resistor circuit 5a which is Y-connected, and the differential amplifier 5b the ground 54c has a potential e ₁ equal detecting DC power supply 54 of the neutral point of the three-phase stator winding 2,
An isolated signal output conversion circuit 5 having a control DC power supply 57 having a common ground with the ground 58 of the three-phase inverter 3
c. The three-phase resistance circuit 5a includes the resistance lines 51,
The non-neutral terminals 52 and 53 are connected to the corresponding non-neutral terminals of the three stator windings 21, 22 and 23 of the three-phase stator winding 2. The differential amplifier 5b receives the potential e ₃ of the neutral point of the three-phase resistance circuit 5a and the potential e ₁ of the neutral point of the three-phase stator winding 2 and receives each potential of the three-phase stator winding 2 The induced voltage of the stator winding is detected, and from the 3 × n harmonics of the fundamental wave included in the induced voltage, the harmonics are tripled as the fundamental wave corresponding to the predetermined rotation position of the permanent magnet rotor 1. only outputs a required rotational position signal e ₃ corresponding. Differential amplifier 5b
Are two DC power supplies 54 in series having the same voltage as the power supply.
a, 54b are connected in series, and a ground of the detection DC power supply 54 is connected between the two DC power supplies 54a, 54b and the neutral point of the three-phase stator winding 2. 54c, the differential amplifier 5
The output voltage of the DC power supply 54a (the positive power supply voltage) and the DC power supply 54b
(The negative power supply voltage) at a high volt, and the output voltage of the differential amplifier 5b is output at a high volt. Isolated signal output conversion circuit 5c
Is an insulation type signal transmission circuit for eliminating an excessively large gap between the output voltage of the differential amplifier 5b and the allowable input voltage of the microcomputer 6. For example, in this embodiment, a primary side element (light emitting diode) 55 And a secondary element (phototransistor) 56 insulated from the primary element 55 and amplifying an electrical change of the primary element 55 to generate an electrical change. A device that combines a light emitting element and a light receiving element that further converts an optical signal into an electric signal is used for the signal, and the rotational position signal e ₃ output from the differential amplifier 5b is input to the input terminal 55a of the primary element 55. The rotation position signal e ₃ is input so as to flow from the output terminal 55 b to the positive side of the DC power supply for detection 54, and the DC The power supply 7, the DC power supply 57 for controlling the secondary element 56 of the insulation type signal output conversion circuit 5 c, the power supply (not shown) of the microcomputer 6, and the commutation control circuit 4
(Not shown) and a ground 58 in common, and is separated from the ground 54c of the DC power supply 54 for detection. The rotation position detection circuit 5 can detect a triple harmonic of a fundamental wave corresponding to a predetermined rotation position of the permanent magnet rotor 1, and a required rotation position signal e corresponding to a triple harmonic of the fundamental wave. No. ₃ can be output.
It is well known that the equivalent circuit is shown in the specification of JP-A-899992 and JP-A-62-189993, which has been described in detail as an electromagnetic theory, so that the theoretical proof is omitted in the present application.

The microcomputer 6 has twelve types of pattern trains corresponding to the output of the three-phase inverter 3 so that the three-phase excitation signal and the two-phase excitation signal alternately output with the phase advanced by thirty degrees in order. by which the first signal group m _1, the second signal output two-phase excitation signal of the three phase inverter 3 is the corresponding six kinds of pattern array to output advances sequentially the phase by sixty degrees A group m ₂ , a pattern repetition period determination program at startup p _1, and a pattern repetition period determination program p ₂ after startup are written in the internal ROM 61.

[0016] Then, the microcomputer 6 controls the current limiter value in the first read signal group m ₁ as an inverter when starting the drive reference signals from the ROM61 After entering the driving signal e ₈ "high level" and outputs a current limiter value control signal e ₇ adapted repeatedly outputs followed by pattern repetition period to the initial excitation to the commutation control circuit 4 as will accelerate gradually until a predetermined short period. At this time, the three-phase inverter 3 performs commutation so that the three-phase stator winding 2 alternates between two-phase excitation and three-phase excitation and the step angle of the rotating magnetic field advances by 30 degrees. When V− and W− are on and transistors V +, W + and U− are off, respectively, in the three-phase excitation state, the V terminal and the W terminal of the motor have the same potential. When the permanent magnet rotor 1 vibrates, the stator windings 22,
23, an alternating current is generated in each of the three-phase stator windings 2 as shown in FIG. 1 (b) with respect to the vibration component of the current (not including the direct current component for rotating the permanent magnet rotor). When three-phase excitation is performed, the phases of both phases are in an inverting relationship with each other, so a closed circuit is formed and flows therethrough to be consumed as Joule heat, and vibration energy is absorbed,
As a result, the vibration generated in the permanent magnet rotor 1 becomes sufficiently small. In the two-phase excitation state, no closed circuit is formed, and no vibration energy is absorbed.

After the motor is started, the microcomputer 6 outputs a signal to switch from synchronous motor operation to sensorless brushless operation. Switching from synchronous motor operation by the microcomputer 6 to the sensor-less brush-less operation, based on the signal the microcomputer 6 inputs a rotational position signal e _3, the pattern repetition period is calculated in a required in each period, each period , The inverter drive reference signal is read from the ROM 61 by reading the second signal group m ₂ and repeatedly output to the commutation control circuit 4.

The microcomputer 6 continues to input the rotation position signal e ₃ as in the above-described sensorless brushless operation even if the microcomputer 6 inputs the stop signal m ₉ by turning off the start switch of the motor. , The pattern repetition cycle is calculated as required for each cycle, and the reading of the inverter drive reference signal from the ROM 61 to the second signal group m ₂ is continued in accordance with each cycle, and the inverter drive reference signal m ₂ is not output to the commutation control circuit 4. The microcomputer 6 outputs by entering the stop signal m _9, the current limiter value control signal e ₇ for controlling from the time the current limiter value of the output current of the three-phase inverter 3 to the "low level".

Then, after the microcomputer 6 receives the stop signal m ₉ , the rotation position detecting circuit 5 detects the induced voltage of the three-phase stator winding 2 and detects the rotation of the permanent magnet rotor 1 based on the detection of the induced voltage. When the operation signal e ₈ is input within the time until the rotation is reduced to the boundary position where the rotation position of the permanent magnet rotor 1 cannot be detected, which is the limit at which the rotation position signal e ₃ corresponding to the position cannot be output, From that time, the inverter drive reference signal m ₂ is repeatedly output, and after a required minute delay time has elapsed from that time, the current limiter value of the output current of the three-phase inverter 3 is changed from “low level” to “high level” again. Current limiter value control signal e
₇ is output. Thereby, it is possible to start the sensorless brushless operation without going through the synchronous motor operation.

Further, the microcomputer 6 comprises:
Outputting a rotational position signal e ₃ corresponding to the rotational position of the permanent magnet rotor 1 based Enter the stop signal m ₉ for the detection of induced voltage of the rotational position detection circuit 5 is a three-phase stator winding 2 it after rotation reduction in rotational position undetectable boundary point of the permanent magnet rotor 1 is a limit that can not, when the operation signal e ₈ is input, the inverter drive reference can not be obtained no longer stable rotation position signals e ₃ Since the signal m ₂ cannot be output so as to be synchronized with the rotation speed of the permanent magnet rotor 1 and loses synchronism, it is necessary to watch whether or not the rotation position reaches the undetectable boundary point. If detected, at that time, a current limiter value control signal for controlling the current limiter value of the output current of the inverter to “high level” is output, and the time constant circuit is further operated to determine whether the rotational position cannot be detected. The operation is restarted because the time until the rotation of the rotor is stopped is set as the restart prohibition time and the initial excitation is performed after the restart prohibition time elapses.

[0021] FIG. 2 (a), six transistors of a three-phase inverter which is operated on the basis of the inverter startup drive reference signal _{m 1 U +, V +,} W +, U-, V-, and W- on and off a function table showing, "1" is turned on, "0" indicates oFF, 2 ^{0-2 5} six transistors U +, V +, W + , U-, V-, and corresponds to the W-. FIG. 2B shows a drive reference signal m at the time of starting the inverter.
₁ shows the direction of the current vector when the three-phase inverter performs the two-three-phase excitation drive based on ₁ . 3 (a) is six transistors of a three-phase inverter which operates when output from ROM61 as an inverter drive reference signal leads the second signal group _{m 2 U +, V +,} W +, U-, V
FIG. 3 (b) is a function table showing ON / OFF states of-and W-.
When the second signal group m ₂ leads to output from OM61, indicating the direction of the current vector when the three-phase inverter is two-phase excitation drive. As shown in the function table of FIG. 2A, the first signal group m ₁ has a pattern 0━
Three-phase excitation signals such that transistors U +, V +, W +, U-, V-, and W- turn on and off in the order of 1━2━3━4━5━6━7━8━9━10━11. And the two-phase excitation signal are written in the ROM 61 as twelve types of pattern sequences that advance and alternate and output the phase in order of thirty degrees, and similarly, the second signal group m ₂ is shown in FIG. As shown in the function table of FIG. 3 (a), the pattern 0━1━2
Transistors U +, V +, W +, U in order of {3} {4} 5
In order that −, V−, and W− are turned on and off, the phase of the two-phase excitation signal is written in the ROM 61 as six types of pattern strings that are sequentially advanced by 60 degrees and output.
Startup pattern repetition period determining program p ₁ is the sequence and timing are determined to lead the inverter startup drive reference signal m _1, after starting the pattern repetition period determination program p ₂ is leading inverter drive reference signal m ₂ The order and timing are determined. Switching from the program p ₁ to the program p _2, it reaches the motor speed that can be sufficiently stably detect startup pattern repetition rotation position signal e ₃ the period has a timer managed in the program p _1, for example, 1800r. p. m
It is adapted to transmit a program switching signal When turned to the program p _2. As shown in FIG. 2B, in the case of two- or three-phase excitation, every time the pattern is switched, the current vector advances by 30 degrees in electrical angle, the step angle of the rotating magnetic field advances by 30 degrees, and FIG. As shown in ()), in the two-phase excitation, the current vector advances by 60 degrees in electrical angle and the step angle of the rotating magnetic field also advances by 60 degrees each time the pattern is switched.

The microcomputer 6, at startup, as the inverter startup drive reference signal acts startup pattern repetition period determining program p ₁ ROM 61
And reads and outputs the first signal group m ₁ from. In this case, among the twelve types of pattern trains constituting the first signal group m ₁ , the commutation control circuit 4 is first read as a three-phase excitation signal as an initial excitation for performing vibration suppression. To about 0.
It is output for 1 second, and then read alternately in the order of the pattern in the order of two-phase excitation signal━three-phase excitation signal━two-phase excitation signal, and repeatedly output to the commutation control circuit 4. Since the excitation after start-up is two-phase excitation, it is configured to read the signal so as to be a two-phase excitation signal, output the signal to the commutation control circuit 4, and end the operation. The ROM 61, the program p ₁ performing repeatedly output lead a first signal group m ₁ above as will accelerate progressively pattern repetition period as an inverter when starting the drive reference signal is written. The program p ₁ manages a basic clock by a timer to calculate a pattern repetition period, and the permanent magnet rotor 1 shifts to a high rotation speed. p. m
Then, the phase difference between the step switching timing and the induced voltage detection signal becomes, for example, 30 degrees, and the program is programmed to gradually increase the pattern repetition period until the pattern repetition period (a predetermined short period) at this time. I have. Then, the program p ₁ detects that the pattern repetition period becomes a predetermined short period, leading to boot after pattern repetition period determination program p _2.

The microcomputer 6 after activation inputs the rotational position signal e ₃ repeating pattern from the rotating position signal e ₃ from the rotational position detecting circuit 5 acts startup after the pattern repetition period determination program p ₂ In each cycle, the next pattern repetition cycle is calculated so that the time from the previous step update to the input of the signal is equal to the time from the input of the signal to the next step update. At the same time, the second signal group m ₂ is read from the ROM 61 as an inverter drive reference signal, and the phase of the output voltage of the inverter 3 is matched with the phase of the induced voltage of the three-phase stator winding 2 to obtain a synchronous motor operation. As a switching adjustment for converting from driving to sensorless brushless motor driving (= DC motor driving), the output of the first reference signal is discontinuously set to the required angle. So as to output example, if 30 degrees to the commutation control circuit 4 to advance and the output of the inverter drive reference signal m ₂ is configured to repeatedly output in accordance with each cycle to the arithmetic. Incidentally, to output to the commutation control circuit 4 so that the step switching timing of the inverter drive reference signal m ₂ proceeds discontinuously required angle is fixed and can be converted to the sensorless brushless motor driving after starting the synchronous motor manner driven This is because it is necessary to match the phase of the output voltage of the inverter 3 with the phase of the induced voltage of the stator winding 2. Is started at 90 degrees, for example, at 1800 r. p. m, the phase difference decreases from 0 degree to about 45 degrees depending on the magnitude of the load, and generally decreases to 30 degrees.
The phase difference can be eliminated by advancing the output of the first reference signal discontinuously by a required angle, for example, 30 degrees.

Further, the microcomputer 6 activates the permanent magnet based on the rotation position signal e ₃ in parallel with the output of the inverter drive reference signal m ₂ after the activation by the operation of the pattern repetition period determination program p ₂ after activation. A rotation speed corresponding signal e ₄ corresponding to the rotation speed of the rotor 1 is output to the commutation control circuit 4.

The commutation control circuit 4 includes a limiter circuit 41, a pulse width modulator (PWM) 42, and a comparator 43. Limiter circuit 41, the current limiter value control signal e ₇ to be output from the microcomputer 6 and input to the inside of the limiter circuit 41, also flows through the transistor from the startup and after activation to the three-phase inverter 3 of the current detection resistor 3a at start A voltage signal e ₉ proportional to the current is input, and an on / off signal is input from a pulse width modulation unit (PWM) 42. The pulse width modulation unit (PWM) 4
The pulse width modulated on / off signal input from 2 is
When the current limiter value control signal e ₇ is 0, the commutation control signal e ₆ is output so that the current limiter value becomes “low level”. When the current limiter value control signal e ₇ is 1, the current limiter value is “ The commutation control signal e ₆ is output so as to be “high level”, and when the voltage signal e ₉ exceeds the limiter value, the commutation control signal e ₆ is output so that all the transistors of the three-phase inverter 3 are turned off. Control. The pulse width modulation section (PWM) 42 receives an inverter startup reference signal m ₁ output from the microcomputer 6 at startup, and receives an inverter drive reference signal m ₂ after startup. The comparator 43 receives a speed command e ₅ from the outside, and outputs a rotation speed corresponding signal e ₄ output from the microcomputer 6 after startup.
To determine the direction of increase or decrease of the pulse width modulation in the pulse width modulation section 42 so as to eliminate the deviation between the rotation speed corresponding signal e ₄ and the speed command e _5. The signal is output to the pulse width modulator 42.

4 to 6 show timing charts. The signals of FIGS. 4 to 6 (a) to (q) will be described with reference to FIG. (A) is a basic clock of the microcomputer 6, (b) is a start / stop signal e ₈ input to the microcomputer 6, and (c) is a current limiter output from the microcomputer 6 to the limiter circuit 41 of the commutation control circuit 4. The value control signals e ₇ and (d) are sent from the microcomputer 6 to the limiter circuit 4 of the commutation control circuit 4.
The first signal group m ₁ to be output to the first and a second signal group m _2, the second rising and falling edges of the signal group m ₂ is generating an output voltage waveform of the three-phase inverter in the microcomputer (E) is an induced voltage detection signal before waveform shaping, which is a deviation between induced voltages e ₁ and e ₂ inputted to two input terminals of the differential amplifier 5b, and (f) is a step switching timing signal as a basis for performing the step switching timing signal. ) Is a rotational position signal e having a magnitude capable of handling the potential by a microcomputer by an insulation type signal output conversion circuit 5c after detecting and shaping the waveform by detecting a harmonic three times the fundamental wave in the induced voltage by the differential amplifier 5b.
₃ , (g), (h), (i), and (j) relate to one phase of the three stator windings 21, 22, 23, and (g) is a three-phase inverter. The induced voltages generated in the one-phase stator winding when the motor rotates while the third transistor group is not turned on / off, (h) and (i) are part of the commutation control signal e ₆ ( Transistors U + and U-, V + and V-, or W + and W- for one phase of the three-phase inverter 3
Is a pair of commutation control signals e ₆ ) and (j) are pulse width modulated inverter output voltages applied to a one-phase stator winding, and (h), (i) and (j) , A number of vertical vertical dotted lines indicate that the waveform is subjected to pulse width modulation, (k) indicates a current limiter value of the limiter circuit 41, and (q) indicates a rotation speed of the permanent magnet rotor.

[0027] Figure 4, the motor is initially energized to stop the vibration and rotation of the rotor, then one revolution twelve and the output to the rotor repeatedly first signal groups m ₁ to cycle faster gradually The two-phase excitation and the three-phase excitation are alternately performed to perform a synchronous motor-like operation to increase the rotation speed of the rotor,
Subsequently required When rotation speed reaches the rotational position signal e ₃ based on the timing of the second calculates the cycle of the signal group m ₂ outputs one rotation six equal parts to sensorless brushless operation performed two-phase excitation of the rotor Shows the correlation of each signal in the operation process of performing. FIG. 5 shows a sensorless brushless operation in which the initial excitation and the synchronous motor operation are omitted when a stop signal is input during operation in the sensorless brushless operation and before an operation signal is input before the rotation is reduced to a rotational position undetectable boundary point. Shows the correlation of each signal in the operation process of shifting again to FIG. FIG. 6 shows that when a stop signal is input during operation in the sensorless brushless operation and then an operation signal is input after the rotation is reduced to a rotational position undetectable boundary point, initial excitation is performed from the elapse of the restart prohibition time and the synchronous motor operation is performed. The correlation of each signal in the operation process of shifting to the sensorless brushless operation is shown. The phase of the induced voltage of the stator winding is advanced by about 90 ° with respect to the phase of the output voltage of the three-phase inverter in the initial stage of the synchronous motor operation at the time of extremely low speed rotation, and the rotational speed is increased. At the end of the operation, the state is advanced by about 30 °, and becomes 0 ° when the pattern is switched to the sensorless brushless operation.

The time chart of FIG. 5 and 6, the stop brushless operation, after stopping the signal e ₈ to the microcomputer 6 of Figure 1 is input, the microcomputer 6 is to stop the three-phase inverter 3, sensorless brushless operation Indicates that detection of the rotor position and speed from the third harmonic of the fundamental wave of the motor induced voltage is continued, and the rotation decreases to the rotation position undetectable boundary point where the detection of the rotor position and speed becomes uncertain. At this point, the brushless stop operation ends. Since the third harmonic becomes smaller as the rotation speed of the permanent magnet rotor 1 becomes lower, the rotation speed at the end of the stop brushless operation, that is, the rotation position undetectable boundary point is:
Set to the lowest speed at which the third harmonic can be reliably detected. According to the experiment, it was confirmed that even if the rotational position undetectable boundary point was set to one-tenth of the rated rotational speed, the third harmonic could be reliably detected, and the microcomputer 6 could operate normally. The microcomputer 6, when the rotational position signal e ₃ reaches the rotational position undetectable boundary points are watching a certain time by operating a time constant circuit inside, and re-start prohibition. This time is the restart prohibition time. Current limiter value control signal e ₇ is a signal outputted from a predetermined output port of the microcomputer 6 to the limiter circuit 41 of the commutation control circuit 4, a time chart of FIG. 5 and FIG. 6, the current limiter value control signal e ₇ is 0 is stopped brushless operation, and 0 continue also de minimis predetermined time after entering the brushless sensorless operation entered operation signal during stopping the brushless operation, during the other operation is 1 It is shown that. The time chart of FIG. 5, when the operation signal e ₈ is input during stop the brushless operation, indicating that outputting the inverter drive reference signal m ₂ to the microcomputer 6 corresponding to the rotational position signal e _3. Current limiter value is of a limiter circuit 41 of the commutation control circuit 4, the current limiter value control signal e ₇ is adapted to be set is switched to the low level and high level, the current limiter value control signal e ₇ current limiter value when the zero current limiter value when a low level, the current limiter value control signal e ₇ is 1 is set to the high level. In the time chart of FIG. 6, the restart prohibition time is 0.5 seconds.

Next, the operation of the sensorless brushless motor according to the first embodiment of the present invention will be described.
When the operation signal e ₈ is input to the microcomputer 6,
The microcomputer 6 outputs the current limiter value control signal e ₇ to the limiter circuit 41 of the commutation control circuit 4 to set the current limiter value of the limiter circuit 41 to “high level” and stores the current limiter value in the ROM 61. The first signal group m ₁ is read and repeatedly output to the commutation control circuit 4.
The microcomputer 6 calculates the pattern repetition period of the inverter startup drive reference signals m ₁ based on the internal clock as will accelerate gradually and timer management.
As an initial excitation for performing vibration suppression, the microcomputer 6 first reads out a three-phase excitation signal so as to be a three-phase excitation signal and outputs the signal to the commutation control circuit 4. The excitation signal is read alternately with the two-phase excitation signal and repeatedly output to the commutation control circuit 4. At the end of startup, the excitation after startup is two-phase excitation. And output it to the commutation control circuit 4. The commutation control circuit 4 inputs the inverter starting drive reference signal m ₁ to a pulse width modulation unit (PWM) 42 and converts the pulse width modulated on / off signal into a limiter circuit 41.
And outputs a commutation control signal e ₆ in which the current limiter value is set to “high level” which is full of the limit. For this reason, the three-phase inverter 3 to which the DC power is supplied from the DC power supply 7 performs twelve times per electric angle rotation of the permanent magnet rotor 1 regardless of the rotation position of the permanent magnet rotor 1 at the time of startup. A three-phase excitation signal and a two-phase excitation signal are input so that the pattern repetition period is controlled so that commutation occurs and the pulse width modulated phase is changed in order of thirty degrees. , V +, W +,
U-, V- and W- are turned on / off to control output lines 31 and 3
2, 33 output an AC voltage for 2-3 phase excitation. Therefore, an exciting current flows through the three-phase stator winding 2, and the induced voltages of the stator windings 21, 22, and 23 are respectively applied to the output voltages 31, 32, and 33 of the corresponding three-phase inverter 3. A rotating magnetic field is generated with the phase advanced by about 90 °,
The permanent magnet rotor 1 rotates in synchronization with the rotating magnetic field. In this case, the drive reference signal m ₁ at the time of starting the inverter is a series of twelve types of patterns in which the three-phase excitation signal and the two-phase excitation signal alternate so that the phase changes in order of thirty degrees. Means that the step angle is advanced by thirty degrees each time the permanent magnet rotor 1 makes an electrical angle of 1/2 turn, and the permanent magnet rotor 1 is driven by a synchronous motor. If the permanent magnet rotor 1 vibrates when the motor is started, an oscillating current is generated in the stator winding of the three-phase stator winding 2 as shown in FIG. When the three-phase stator winding 2 is three-phase-excited, the induced current flows in a closed circuit in an inverse relationship with each other to be consumed as Joule heat, and vibration energy is absorbed. When the three-phase stator winding 2 is three-phase excited, the vibration of the permanent magnet rotor 1 can be greatly suppressed, the operation time of the synchronous motor can be shortened, and the reverse rotation phenomenon of the permanent magnet rotor 1 hardly occurs. Even when the load fluctuates or the load inertia is large, a stable starting characteristic can be obtained from a state where the rotation of the permanent magnet rotor 1 is completely stopped. Then, the microcomputer 6 outputs the inverter starting drive reference signal m ₁ to the commutation control circuit 4 so as to gradually increase the inverter starting drive reference signal m ₁ in the pattern repetition cycle. The rotor 1 is gradually accelerated, and the pattern repetition period is set to a predetermined short period (for example, 1800 rpm in terms of the rotation speed of the permanent magnet rotor 1) so that the permanent magnet rotor 1 rises to a predetermined rotation speed. At the point of time when the output to the commutation control circuit 4 is accelerated to m), the above-described synchronous motor driving is completed, and thereafter, the vibration generated in the permanent magnet rotor 1 becomes extremely small. The progress of the induced voltage of the three-phase stator winding 2 with respect to the output voltage of the inverter 3 is gradually reduced from 90 degrees at the initial stage to 30 degrees at the end stage in conjunction with the acceleration of the permanent magnet rotor 1. , The harmonic of three times the induced voltage of the three-phase stator winding 2 and the rotational position signal e of the rotational position detection circuit 5.
The phase difference with ₃ also decreases.

The microcomputer 6 switches the signal mode read from the ROM 61 from the inverter startup reference signal m ₁ to the inverter drive reference signal m ₂ when the pattern repetition cycle that was being watched at startup becomes a predetermined short cycle. Read and output to the pulse width modulator (PWM) 42 of the commutation control circuit 4 and input the rotation position signal e ₃ from the rotation position detection circuit 5 to calculate the pattern repetition cycle for each cycle and rotate Speed corresponding signal e ₄
Is repeatedly output to the comparator 43 of the commutation control circuit 4. If necessary, the microcomputer 6 updates the inverter drive reference signal m ₂ in steps so as to discontinuously advance the step switching timing by a required angle, and outputs it to the commutation control circuit 4 to output the three-phase stator winding. 2 stator windings 2
The phase of the output voltage of the inverter 3 is advanced to match the phase of the induced voltage of 1, 22, 23. Therefore, the commutation control circuit 4 inputs a code for determining the increase / decrease direction of the pulse width modulation from the comparator 43 to the pulse width modulation unit (PWM) 42, and based on the code, determines the pulse width modulation unit (PWM). The pulse width modulation is performed on the inverter driving reference signal m ₂ input to the limiter circuit 42, and is input to the limiter circuit 41.
_{If 9} exceeds the limiter value, the three-phase inverter 3
All transistors of the outputs a commutation control signal e ₆ so as to turn off. For this reason, the three-phase inverter 3 inputs the commutation control signal e ₆ of the two-phase excitation that generates six commutations per one electrical angle rotation of the permanent magnet rotor 1 and receives the internal transistor groups U +, V +, W +. , U-, V-, and W- are controlled to be turned on and off to output a two-phase excitation AC voltage from the output lines 31, 32, and 33, so that the two-phase excitation induced current flows through the three-phase stator winding 2. 6 commutations per electrical angle rotation, and
A rotating magnetic field is generated such that the induced voltages of the stator windings 21, 22, and 23 have the same phase as the output voltages of the corresponding output lines 31, 32, and 33 of the three-phase inverter 3, respectively. , The permanent magnet rotor 1 rotates to drive the sensorless brushless motor, and the electric-mechanical energy conversion equivalent to that of the DC motor is performed. Then, the commutation control circuit 4 compares the rotation speed corresponding signal e ₄ with the speed command e ₅ input from the outside, determines the direction of increase or decrease of the pulse width modulation based on the sign of the comparison result, and Since the commutation control signal e ₆ is output so as to gradually reduce the deviation between the signal e ₄ and the speed command e ₅ , the permanent magnet rotor 1 is accelerated according to the commutation control signal e ₆ so as to be at a steady speed in synchronization with the rotating magnetic field. Will be done.

In the above case, two DC power supplies 54 connected in series as the detection DC power supply circuit 54 of the differential amplifier 5b
a, 54b, and a point between the DC power supplies 54a, 54b and a neutral point of the three-phase stator winding 2 are connected as a ground 54c of the DC power supply circuit 54 for detection, and the ground 54c is connected to the three-phase inverter. 3, the input voltage of the differential amplifier 5b becomes independent of the fluctuation of the voltage of the DC power supply 7 of the three-phase inverter 3,
The amplitude of the harmonic detection voltage (the deviation of the voltage between the input terminals + and-of the differential amplifier 5b) three times the fundamental wave of the motor induced voltage can be obtained much larger than in the conventional case. Then, the value of the rotational position signal e ₃ output from the differential amplifier 5b, since the DC power source of the microcomputer 6 is another DC power supply signal, in the present invention, electrically insulated primary element 5
5 and the secondary-side element 56 made of an insulating type that outputs a rotational position signal e ₃ that by applying a rotational position signal e ₃ to be output from the differential amplifier 5b to the primary side element 55 is induced in the secondary side element 56 by having a signal output conversion circuit 5c, transmits the rotation position signal e ₃ to the microcomputer 6, as the voltage of the DC power supply 7 of the three-phase inverter 3 varies the minimum value closer, from the secondary device 56 The rotational position signal e ₃ output and input to the microcomputer 6 is much more stable than before, and is sufficiently reliable that no malfunction occurs in the microcomputer 6 at the stage when the rotor speed is much lower than before at startup. A rotational position signal e _{3 having a characteristic} is obtained. Therefore, the conventional problems of failure in starting, rotation of the rotor, and loss of synchronism of the rotor are solved, and
The switching frequency from the synchronous motor operation to the sensorless brushless operation can be made lower than before, and the synchronous motor operation time (= start-up time) can be reduced.

When the microcomputer 6 receives the stop signal e ₈ during operation, the microcomputer 6 thereafter reads the ROM 6.
1 to stop reading the inverter drive reference signal m ₂ and repeatedly outputting it to the commutation control circuit 4. Subsequently, the rotation position signal e ₃ is input from the rotation position detection circuit 5 and the pattern repetition period is changed every one cycle. Is calculated. Therefore, the three-phase inverter 3 does not receive the commutation control signal e ₆ corresponding to the inverter drive reference signal m ₂ from the commutation control circuit 4, so that the two-phase excitation AC voltage is output from the output lines 31, 32 and 33. The output stops, the rotating magnetic field of the three-phase stator winding 2 is demagnetized, and the rotation speed of the permanent magnet rotor 1 decreases. Then, the microcomputer 6 outputs the stop signal e
_{When the} operation signal e ₈ is input within a time period from the input of the stop signal ₈ until the rotation of the permanent magnet rotor 1 is reduced to the boundary point where the rotational position cannot be detected, the operation signal e ₈ is continuously input after the stop signal is input as described above. The inverter drive reference signal m ₂ is read from the ROM 61 and repeatedly output to the commutation control circuit 4 so as to correspond to the calculated pattern repetition cycle, thereby controlling the commutation so that the commutation control circuit 4 does not step out. Since the signal e ₆ is output, the phase of the output voltage of the three-phase inverter 3 can be immediately adjusted to the phase of the induced voltage of the three-phase stator winding 2, and the sensorless brushless motor is driven again, and the electric power equivalent to the DC motor is obtained. A mechanical energy conversion takes place;

Further, the microcomputer 6 stops the rotation of the permanent magnet rotor 1 after a lapse of time from the input of the stop signal e ₈ to the rotation of the permanent magnet rotor 1 to the boundary point where the rotational position cannot be detected. If the operation signal e ₈ is input before the start of the operation, the motor loses synchronism even after re-driving. Therefore, the rotation of the permanent magnet rotor 1 is reduced to the boundary point where the rotational position cannot be detected. The operation is restarted from the initial excitation after the restart prohibition time, which is a slightly longer time including the time until the rotation stops, after the restart prohibition time. As described above, also in the initial excitation at the time of restarting the operation, an oscillating current is generated in the stator winding of the three-phase stator winding 2 and the induced current is generated when the three-phase stator winding 2 is three-phase excited. In addition, the fluid flows in a closed circuit in an inverted relationship and is consumed as Joule heat, the vibration energy is absorbed, the vibration of the permanent magnet rotor 1 can be largely suppressed, and the rotation of the permanent magnet rotor 1 is reduced. Stable starting characteristics can be obtained from a completely stopped state.

FIGS. 7 to 10 show a second embodiment of the present invention. The sensorless brushless motor of this embodiment differs from the first embodiment in the configuration of the microcomputer 6. Therefore, the description of the sensorless brushless motor of this embodiment will be made only for the parts different from those of the first embodiment. As shown in FIG. 7, the microcomputer 6
ROM61 to have the second signal group m ₂ indicated is written FIG. 8 (a), the startup, the startup pattern repetition period determination program p _1, said second signal group m ₂ is an inverter startup drive It is output to the commutation control circuit 4 as a reference signal, and after the start, the second signal group m ₂ is commutated as an inverter drive reference signal by the post-start pattern repetition cycle determination program p ₂ . The signal is output to the control circuit 4. FIG. 8B
As shown, the signal groups m ₂ of said second are six kinds of pattern sequence output two-phase excitation signal of the three-phase inverter 3 corresponds to output advances sequentially the phase by sixty degrees. When the operation signal e ₈ is input, the microcomputer 6 reads the second signal group m ₂ from the ROM 61 as a drive reference signal at the time of starting the inverter, performs initial excitation, and gradually accelerates the pattern repetition cycle until a predetermined short cycle. The synchronous motor operation is performed by repeatedly outputting to the commutation control circuit 4 as much as possible. When the operation is switched to the sensorless brushless operation after the start, the rotational position signal e is output.
₃ enter the a second signal group m ₂ combined pattern repetition period and calculates the required in each cycle to each period repeatedly outputs the read from the ROM61 as an inverter drive reference signal, the stop signal e ₈ while stopping the output of the inverter drive reference signal m ₂ After entering, the rotational position signal e ₃ continue to input pattern repetition period for each one period continue to operation the required, if, by inputting the stop signal e ₈ When the operation signal e ₈ is input during the period from when the rotation of the permanent magnet rotor 1 is reduced to the boundary position where the rotational position cannot be detected, the second signal group m ₂ is used as an inverter drive reference signal and the pattern repetition cycle together ROM61 is adapted to resume operation repeatedly output to the lead than, if also the rotational position detection of the permanent magnet rotor 1 from the input stop signal e ₈ to When the operation signal e ₈ after rotation reduction is input to the non boundary point,該再start prohibition time elapsed time from the rotational position undetectable border point to the permanent magnet rotor 1 stops rotating restart prohibition time After the initial excitation, the operation is restarted.
In this manner, the second embodiment, since the second signal group m ₂ is an inverter startup drive reference signal, unlike the first embodiment, the time for damping by initial excitation since oscillating current is not generated Lengthen. According to the experimental results, the time required to achieve the initial excitation for damping the permanent magnet rotor was 0.1 seconds in the first embodiment and 0.3 seconds in the second embodiment. . In the first embodiment, the time up to the end of the synchronous motor operation including the initial excitation is set to 0.
It took 3 seconds, and 2.5 seconds in the second embodiment.

According to the above two embodiments, after the initial excitation, the drive reference signal at the time of starting the inverter is output to the commutation control circuit and the commutation control circuit is started. The inverter drive reference signal is output in accordance with the timing, and even if the stop signal is input, the rotation position signal is input and the pattern repetition period is calculated, and the rotation of the permanent magnet rotor to the rotation position undetectable boundary point is reduced. When the operation signal is input to the inverter, the inverter drive reference signal is output in accordance with the pattern repetition cycle from that point on, and the operation is restarted. When the stop signal is input, the operation is restarted from the initial excitation after the restart prohibition time has elapsed. When trying to resume during) driving operation it can suddenly restarted from sensorless brushless operation without completely stopping the rotation of the permanent magnet rotor omitted restart prohibition time and the initial excitation and synchronous motor operation. Further, in the present invention, the restart prohibition time can be shortened from about 6 seconds to 0.5 seconds from the conventional restart prohibition time by dividing into the stop brushless operation and the restart prohibition time in the present invention. The operation can be resumed after a lapse of 0.5 seconds even when the operation is to be resumed a short time after the stop signal is input and the stop brushless operation time elapses.

The present invention is not limited to the above two embodiments. FIG. 11A shows a voltage dividing resistor 59a of the sensorless brushless motor of the first embodiment shown in FIG.
FIG. 11 is a block circuit in the case where the motor neutral point voltage input to the differential amplifier 5b is divided by providing
FIG. 7A is a block diagram of the sensorless brushless motor according to the second embodiment shown in FIG. 7 in which a voltage dividing resistor is provided to divide a motor neutral point voltage input to the differential amplifier 5b. This is because, for example, when the DC voltage of the DC power supply 7 of the three-phase inverter 3 is 113 to 170 V and the voltage of the control power supply 57 is 5 V, the motor neutral point voltage is 56.5 to 85.
V and a very high motor neutral point voltage of 56.5 to 85 V cannot be connected to the differential amplifier 5b, so the voltage is divided by the voltage dividing resistors 59a to 59h. In this modification, a voltage dividing resistor is provided as in FIG. 12, but the ground of the DC power supply circuit for detection of the differential amplifier 5b is provided independently, and the rotational position signal is converted to an insulated signal output conversion circuit. It is configured to flow to the primary side element and output as a stable rotational position signal that can be handled by a microcomputer from the secondary side element, so that the voltage of the DC power supply of the three-phase inverter fluctuates to a minimum value However, since the input voltage of the differential amplifier 5b is not related to the fluctuation of the voltage of the DC power supply 7, the division ratio does not increase, and the rotational position signal e ₃ output from the differential amplifier 5b is different from the conventional one. Obtained more stably. On the other hand, if the motor induced voltage is, for example, 8
When the voltage is 0 V, the triple harmonic voltage is about 4 V, and there is no need for voltage division. Therefore, the block circuit shown in FIG. 1 or 7 is employed.

In addition, in the first embodiment, the microcomputer 6 adjusts the phase of the output voltage of the inverter 3 to the phase of the induced voltage of the three-phase stator winding 2 when switching from the start to the start. , to advance required angle step switching timing discontinuously, but the inverter drive reference signal m ₂ and step updates and outputs the commutation control circuit 4, this is not necessary manner. The reason is that the stator windings 21 and
A rotating magnetic field is generated in a state in which the induced voltages 2, 23 are advanced by about 90 ° with respect to the output voltages of the corresponding output lines 31, 32, 33 of the three-phase inverter 3, respectively, but the number of rotations is increased. When the phase shift often approaches 0 °, there is no need for phase matching. When phase matching is required, the phase shift is 20 ° to 30 ° even when the rotation speed increases.
° It is sufficient to carry out only under operating conditions that remain. Further, the present invention adopts not the pulse width modulation type but the amplitude modulation type as the three-phase inverter 3,
Accordingly, a current limiting circuit and an amplitude modulation section (PAM) may be employed instead of the limiter circuit 41 and the pulse width modulation section (PWM) 42 of the commutation control circuit 4. Further, the rotational position detecting circuit 5 does not have to have a structure for detecting the induced voltage, but only needs to detect the rotational position signal of the permanent magnet rotor 1. A structure adopting a method of detecting a rotational position shown in a rotor position detecting circuit of a non-commutator motor of -25038 may be used.

[0038]

As described above, according to the sensorless brushless motor of the present invention, the ground of the DC power supply circuit for detection of the differential amplifier is provided independently and is connected to the neutral point of the motor. Rotational position signal in which the input voltage of the differential amplifier becomes the third harmonic voltage of the fundamental wave of the induced voltage of the motor irrespective of the fluctuation of the DC power supply voltage of the three-phase inverter, and is output stably from the differential amplifier. Flows into the primary element of the insulated signal output conversion circuit, and is output from the secondary element as a stable rotational position signal that can be handled by a microcomputer. Even if it fluctuates toward the minimum value, the rotational position signal output from the secondary side element and input to the microcomputer is much more stable than before, At a stage where the number is much smaller than in the past, a sufficiently reliable electrical magnitude rotation position signal that does not cause a malfunction in the microcomputer is obtained, and therefore, the differential amplifier and the three-phase inverter are conventionally grounded. When the voltage of the DC power supply of the three-phase inverter fluctuates near the minimum value due to the fact that it is common, the rotation position signal becomes abnormally small and unstable, leading to startup failure, rotor reversal, rotor loss of synchronization. In addition to eliminating the conventional problems, the switching frequency from the synchronous motor operation to the sensorless brushless operation can be made lower than before, so that the synchronous motor operation time (= start-up time) can be shortened.

[Brief description of the drawings]

FIG. 1A is a block diagram of a sensorless brushless motor according to a first embodiment of the present invention, and FIG. 1B is a diagram for explaining that a closed circuit of a vibration component voltage is generated at the time of three-phase excitation at startup.

FIG. 2 is a function table showing an ON / OFF pattern sequence in which six transistor groups of a three-phase inverter operate based on a first signal group according to the first embodiment of the present invention. FIG. 6B is a diagram illustrating a direction of a current vector when the three-phase inverter performs two- to three-phase excitation driving based on the first signal group.

FIG. 3 is a function table showing an on / off pattern sequence in which six transistor groups of a three-phase inverter operate based on a second signal group according to the first embodiment of the present invention; FIG. 7B is a diagram illustrating the direction of a current vector when the three-phase inverter performs two-phase excitation driving based on the second signal group.

FIG. 4 is a timing chart showing initial excitation {synchronous motor operation} sensorless brushless operation of the sensorless brushless motor according to the first embodiment of the present invention.

FIG. 5 is a timing chart showing a sensorless brushless operation of the sensorless brushless motor according to the first embodiment of the present invention, a stop signal input, and a sensorless brushless operation.

FIG. 6 is a timing chart showing a sensorless brushless operation of the block circuit of the sensorless brushless motor according to the first embodiment of the present invention, stop, initial excitation, synchronous motor operation, and sensorless brushless operation.

FIG. 7 is a block diagram of a sensorless brushless motor according to a second embodiment of the present invention;

FIG. 8 is a function table showing an ON / OFF pattern sequence in which six transistor groups of the three-phase inverter operate based on the second signal group according to the second embodiment of the present invention. FIG. 7B is a diagram illustrating the direction of a current vector when the three-phase inverter performs two-phase excitation driving based on the second signal group.

FIG. 9 is a timing chart showing a sensorless brushless operation of a sensorless brushless motor according to a second embodiment of the present invention, a stop signal input, and a sensorless brushless operation.

FIG. 10 shows a sensorless brushless operation of the sensorless brushless motor according to the second embodiment of the present invention {stop} initial excitation;
7 is a timing chart showing synchronous motor operation and sensorless brushless operation.

FIG. 11 is a block diagram when voltage is divided for the sensorless brushless motor according to the first embodiment of the present invention.

FIG. 12 is a block diagram of a sensorless brushless motor according to a second embodiment of the present invention when voltage is divided.

13A is a block diagram of a conventional sensorless brushless motor, and FIG. 13B is a function showing an on / off pattern sequence in which six transistor groups of a three-phase inverter operate based on a second signal group. Table
(C) is a diagram showing the direction of a current vector when the three-phase inverter performs two-phase excitation driving based on the second signal group.

FIG. 14 is a timing chart showing initial excitation of a conventional sensorless brushless motor, synchronous motor operation, and sensorless brushless operation.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Permanent magnet rotor, 2 ... Three-phase stator winding, 3 ... Three-phase inverter, 31 ... Voltage output line, 32 ... Voltage output line, 33 ... Voltage output 4, commutation control circuit, 41, limiter circuit, 5, rotational position detection circuit, 5 a, three-phase resistance circuit, 5 b, differential amplifier, 5 c, insulation type Signal output conversion circuit 54 DC power supply circuit for detection 54a, 54b DC power supply 54c Ground for DC power supply circuit for detection 55 Primary element 56 Secondary Element 58 58 Ground 6 Microcomputer 61 ROM m ₁ m ₂ Signal group 7 DC power supply

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02P 6/18 H02P 6/12

Claims (1)

(57) [Claims] 1. A permanent magnet rotor and three stator windings are Y
The connected three-phase stator windings and the transistor groups U +, V +, W +,
A three-phase inverter for controlling the commutation of a three-phase stator winding by outputting an AC voltage to an output line by controlling ON / OFF of U-, V- and W- as required, and commutating to the three-phase inverter A commutation control circuit that outputs a control signal, three resistance wires are connected in Y in parallel with the three-phase stator winding, and a non-neutral terminal of each resistance wire is connected to the three stator windings. It has a three-phase resistor connected to the non-neutral side terminal of the wire, and inputs the neutral point potential of the three-phase stator winding and the neutral point of the three-phase resistor to obtain A differential amplifier that detects an induced voltage of the stator winding and outputs a required rotation position signal corresponding to only a triple harmonic of a fundamental wave corresponding to a predetermined rotation position of the permanent magnet rotor. A rotation position detection circuit; and a microcomputer interposed between the rotation position detection circuit and the commutation control circuit. In the micro computer, a signal group as an inverter drive reference signal for performing two- or three-phase excitation or two-phase excitation at startup and as an inverter drive reference signal after startup is written in an internal ROM. All or a part of the signal group is repeatedly output to the commutation control circuit so as to gradually increase the pattern repetition cycle to a predetermined short cycle, and after startup, the rotational position signal is input to set the pattern repetition cycle. is configured to repeatedly outputs all or part of the signal group combined by calculating the required in each cycle to each period, also, the rotational position detecting circuit for detecting the DC power supply circuit of the differential amplifier And a point between these DC power supplies and a neutral point of the three-phase stator winding as a ground of the DC power supply circuit for detection. And a rotational position which is composed of an electrically isolated primary side element and a secondary side element, and which causes a rotational position signal output from the differential amplifier to flow through the primary side element to induce on the secondary side element. A sensorless brushless motor having an insulated signal output conversion circuit for outputting a signal.