JPS6220792B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a brushless DC motor, and particularly to a brushless DC motor that does not have a detection element such as a Hall element to recognize the rotational position angle of a permanent magnet rotor. It is about improvement.

Brushless DC motors do not have mechanical contacts compared to DC motors with brushes, so they have a long life and produce less electrical noise, making them suitable for industrial equipment that requires high reliability in recent years, as well as audio equipment. It has also been widely used in consumer devices. Most of these brushless motors use a permanent magnet rotor position detecting means (for example, a Hall element) corresponding to a brush to switch the energizing phase of the excitation winding. However, the rotor position detection means is by no means inexpensive, and since it must be installed inside the motor, there are often structural limitations.

Several brushless electric motors have been proposed in the past that do not have such a rotor position detecting means, for example, a detecting element such as a Hall element. One method is to use a ring-shaped oscillation circuit having a motor winding and a bistable circuit or a phase shift circuit to sequentially switch the energized phases as the rotor rotates. In this method, the setting of the oscillation frequency of the circuit itself is important and has a great influence on the motor's performance, such as efficiency and torque. Therefore, compared to a brushless motor having a position detecting means such as a Hall element, it is inferior in terms of characteristics.
For example, it is not suitable when the load conditions change significantly or when it is necessary to change the rotation speed, and the adaptability is poor.

To give yet another example, there is a method of driving a permanent magnet rotor by applying an alternating current voltage having a constant frequency to the stator windings from an external oscillator. This method is also not suitable when large load fluctuations are applied.
As an electric motor, the power loss should increase or decrease depending on the load, but the above method basically always requires power corresponding to the maximum load, and is extremely inefficient at small loads, and also has large torque ripple. . The means to improve this is quite complicated.

To give yet another example, there is a method of extracting a back electromotive force signal induced in an excitation winding, processing the signal, and using this as a position signal to drive the winding. Although this method requires a fairly complex circuit, recent advances in integrated circuit technology have made it relatively easy and inexpensive to implement.

The present invention belongs to the last example of the above, and proposes a new brushless electric motor. As a result, it is possible to realize a motor that is comparable to brushless motors having a rotor position detection means such as a Hall element.

Particularly, the present invention provides a brushless electric motor of a self-starting direction and restarting type, which can reach a normal rotational state by turning the rotor by a small angle at the time of starting.

The invention will now be explained in terms of aspects. FIG. 1 is a conceptual diagram of a motor and a winding drive transistor according to the present invention. 1 is a permanent magnet rotor. 2
a, 2b, 2c are stator windings. 3a, 3b, 3c
are winding drive transistors that drive the windings, and 4a, 4b, and 4c are their base terminals. 5 is a terminal connected to a positive DC power supply + _Vcc . The motor is driven by winding drive transistors 3a and 3 according to the rotational position angle of the rotor 1.
This is done by applying sequentially switched base currents to base terminals 4a, 4b, 4c of terminals b and 3c. Note that this figure shows a 2-pole, 3-phase (2-pole, 3-winding group) motor, and the following explanation will follow, but please be aware that the number of poles and phases are not limited to these. .

Now, FIG. 2 shows the back electromotive force of the windings of the motor shown in FIG. 1, especially the winding drive transistors 3a, 3b, 3c.
This represents the collector potential of . 11 in the diagram
a, 11b, and 11c are the time transitions of the collector potentials of the winding drive transistors 3a, 3b, and 3c, respectively, and the broken line in particular is the waveform of the back electromotive force when the rotor 1 is turned from the outside. Furthermore, the solid line represents the waveform when the motor is actually driven and rotates on its own, and a voltage drop due to the drive current and winding resistance (only the waveform 11a is particularly shaded) can be seen. This voltage drop increases as the generated torque increases.

Now, by using the back electromotive force of the windings, this is phase switched, that is, the winding drive transistors 3a, 3b, 3c.
In order to use it for switching the base current of the back electromotive force, first, as is clear from FIG. 2, the non-current-carrying region of the back electromotive force waveform must be used. That is, for example, the second
Regarding the figure, the area above the DC power supply voltage + _Vcc must be used. The area below this cannot be used because it includes an energized area. In the electric motor according to the present invention, the non-current-carrying regions 11a and 11b (particularly the region above +V _cc ) are used to connect the winding 2.
Similarly, winding 2 is driven by 11b and 11c.
11c and 11a drive the winding 2b, respectively. Furthermore, in the electric motor according to the present invention, the area of the back electromotive force of the winding, especially in _FIG . Focusing on the fact that it _{is constant} without depending on This is used as a so-called position signal for driving the winding 2c, and in the same way, the temporal subtraction integral of 11c is obtained from the temporal addition integral of 11b to drive the winding 2a.
The temporal addition integral of 1c and the temporal subtraction integral of 11a are used as position signals for respectively driving the windings 2b.

FIG. 3 shows the integral calculation of the back electromotive force of the motor according to the present invention. Figure 3a
represents the back electromotive force (collector potential of the winding drive transistor) of the same winding as shown in FIG. Third
Figure b shows the temporal addition and integration of the hatched part 11a in Figure 3a, and the temporal subtraction integration of the hatched part 11b, which is used as a position signal for driving the winding 2c. It is equivalent. In the same way, Fig. 3c is a result of temporally adding and integrating the hatched part 11c in Fig. 3a, and subtracting and integrating the hatched part 11c in time, thereby driving the winding 2a. 3d corresponds to the position signal for the hatched part 11a in FIG. 3a from the temporal addition integral of the hatched part 11c, This corresponds to a position signal for driving the winding 2b. The peak of each position signal matches the corresponding drive winding phase. Further, the peak value of the peak is always constant (E _c ) regardless of the rotation speed of the rotor. This is because, as mentioned above, the area of the back electromotive force of the winding is constant regardless of the rotation speed. This is extremely important, as the magnitude of the position signal (peak value) is always constant no matter what rotation speed the motor rotates. It is very convenient because you can get the same effect as . Therefore, ultra-low speed rotation can be easily achieved, and the poor self-starting characteristic of this type of motor can be compensated for with a relatively simple circuit.

Furthermore, in the electric motor according to the present invention, FIGS. 3b, c,
The position signal created by the integral calculation of the back electromotive force shown in d is directly transmitted to the drive transistors 3a, 3b,
Although it may be given as a base current of 3c, as it is, overlapping of drive currents tends to occur, so these three position signals are converted into a signal (for example, a base current) that smoothly switches through three differential circuits.

FIG. 4 shows the waveform of a position signal (eg, base current) that switches smoothly through a three-differential circuit. The waveform 21c drawn with a solid line in the figure is a signal that drives the winding 2c, and the waveform 21a drawn with a broken line is a signal that drives the winding 2a.
This is the signal that drives the waveform 2 drawn by the dashed line.
1b is a signal that drives winding 2b. Passing the position signal through a differential circuit as described above is already well known, but by combining this, it is possible to prevent undesirable overlap of the winding drive currents, achieve smooth phase switching, and reduce vibration and torque ripple. This makes it possible to realize a good electric motor with less. However, in this case, it is desirable to provide some kind of electrical trigger or to apply a slight external force to the rotor. As a result, after the rotor turns a small angle, it reaches a normal rotational state, and thereafter it becomes possible to control the rotor at any desired rotational speed.

FIG. 5 is a block diagram representation of the concept of the present invention. In the figure, 2a, 2b, and 2c are stator windings common to those in FIG. Similarly, 3a, 3b, and 3c are wire-wound drive transistors. 30a, 30b, 3
0c is a type of rectifier circuit for extracting the non-current-carrying region of the back electromotive force of each winding (particularly the portion above +V _cc here). 31a, 31b, 31c
1 is a discharge type voltage-current conversion circuit that converts the half-wave waveform of the back electromotive force obtained in each of the rectifier circuits 30a, 30b, and 30c into a current. Similarly 32a, 32
b and 32c are attraction type voltage-current conversion circuits. 33
a, 33b, and 33c are voltage-current conversion circuits 31b and 32c, 31c and 32a, and 31a and 32, respectively.
A time-integrating capacitor charged and discharged by b.
34 is an appropriate DC voltage bias. Reference numeral 35 designates a differential comparator circuit for smoothly and sequentially switching the drive current according to the position signal stored in the capacitor, and here an example is shown in which it is composed of three differential transistors 36a, 36b, and 36c with a common emitter. . 3
7 is the winding drive current command. 38 is a winding drive circuit,
Especially here, the current amplifying transistors 39a, 39
b, 39c and winding drive transistors 3a, 3b,
An example configured with 3c is shown below.

Next, 22 is a self-starting circuit which is a feature of the present invention and basically consists of a DC power supply and a switch.
The DC power sources 23a, 23b, and 23c have voltage values _ea , _eb , and _ec , respectively, and provide initial values for the time-integrating capacitors 33a, 33b, and 33c that are charged and discharged. Switches 24a, 24b, 24
C is a transfer switch that is closed for a certain period of time at startup, and at that time, the voltage e _a of the DC power supply 23a is transferred to the capacitor 33a, and in the same way, the voltage e _b of 23b is transferred to 33b, and the voltage e _c of 23c is transferred to 33c. The data is transferred and the initial value of the time integration capacitor is determined. Next, switches 25b and 25c are positioning switches that are opened for a certain period of time during startup, contrary to the above, and are provided for positioning the rotor of the electric motor.

Next, the operations and functions shown in FIG. 5 will be explained. There is no need to explain the process of half-wave rectification of the back electromotive force generated in the winding (extracting the part above + _Vcc ), converting it into a current form, adding, subtracting, and integrating it, so it will be omitted. However, in this integration, a capacitor is used and the integral calculation is performed in an analog manner by charging and discharging the capacitor. Next, the self-starting circuit 22 will be explained. At the time of startup, for example, when the power is turned on, the charge on the time integrating capacitors 33a, 33b, and 33c, which should indicate the position signal of the permanent magnet rotor, is zero. Then, if the self-starting circuit 22 is not present, the differential comparator circuit 3 that receives the position signal and switches the current
5 three differential transistors 36a, 36b, 36c
Since the bases of the transistors 36a, 36b, and 36c have the same potential, the winding drive currents will be almost the same as a result if the characteristics of the transistors 36a, 36b, and 36c are well matched. Since both collector potentials are lower than +V _cc ,
Even if the rotor moves slightly in a certain direction due to this current, the back electromotive force is small, so it will not exceed the +Vcc threshold, and the time integrating capacitor 33 will not exceed the + _Vcc threshold.
A, 33b, and 33c are not charged or discharged and are not activated. Actually, the transistor 36
Due to variations in a, 36b, and 36c, and subsequent differences in current amplification factors, the current often flows only to a specific winding, and this tendency is particularly noticeable when incorporating a feedback system that keeps the total current in the windings constant. . Therefore, if the rotor moves slightly in a certain direction due to this current, the back electromotive force in a certain winding may exceed the + _Vcc threshold, and as a result, some of the time integrating capacitors 33a, 33b, 33c It may also be charged and activated. However, this cannot be said to be certain from a probabilistic standpoint. The self-starting circuit 22 solves this drawback, and at startup, the time integrating capacitors 33a, 33b, 33 are forcibly connected to each other.
The purpose is to give an initial value to c. For this purpose, DC power supplies 23a, 23c, and 23c having voltage values e _a , e _b , and e _c are provided, respectively, and transfer switches 24 a, 23 c, which are closed only for a short time at startup, are provided.
Capacitors 33a, 33 through 24b, 24c
The above voltage value is charged and transferred to terminals b and 33c. By doing this, only a specific winding can be driven at startup, so if the rotor moves in a certain direction, the back electromotive force in the other windings will exceed the + _Vcc threshold and be halved. Since the waves are now rectified, new position information is provided to the integrating capacitor, so that starting is more reliable.

However, in this case, the rotation direction of the rotor is not determined at the first moment of startup, and it may start to rotate in the opposite direction, and then after a while, it may reach normal rotation, so it takes a little time to start. There is. Therefore, in the present invention, in order to further eliminate this drawback, the rotor is positioned before or at the same time as starting, and an initial value that matches the rotor position is set to the time integral capacitor 33.
By applying the signals to the signals a, 33b, and 33c, the time required for activation is controlled to be further shortened, and at the same time, more reliable activation is ensured. Positioning of the rotor can be achieved by energizing only specific windings for a short period of time during startup, and in the conceptual block diagram shown in FIG. There is.
When the positioning switches 25b and 25c are opened, only 36c of the three differential transistors of the differential comparator circuit 35 becomes conductive, regardless of the information on the time integration capacitors 33a, 33b, and 33c, and the drive current only flows to the stator winding 2c. flows. The method of energizing only a specific winding is not limited to the one shown in FIG.
For example, a base current may be externally applied to one of the winding drive transistors 3a, 3b, and 3c, so that the other base currents do not flow.

Note that transfer switches 24a, 24 that close at startup
The closing time of the positioning switches 25b, 24c must be equal to or shorter than the opening time of the opening positioning switches 25b, 25c. This is because when the switches 25b and 25c are closed and the rotor starts rotating normally, the time integral capacitors 33a, 33b, 33
This is because c must be charged and discharged in accordance with the back electromotive force generated in the winding, and must not be subjected to any forced charging or discharging from any other source. Therefore, if you want to sequentially set the closing time of the transfer switches 24a, 24b, 24c immediately after the positioning switches 25b, 25c close, that is, the time integrating capacitors 33a, 33 should be set immediately after the rotor positioning is completed.
It is clear that when it is desired to transfer the initial values to the transfer switches 24a, 24b and 33c, the length of time that the transfer switches 24a, 24b and 24c are closed must be extremely short.

Furthermore, all the signal lines in Fig. 5 are 3 lines, but this is because there are 3 stator windings (3
Therefore, if the number of winding phases changes, the number of paths should also change accordingly.
It is not limited to routes.

FIG. 6 is a waveform diagram illustrating the process during self-startup of the present invention. FIG. 6a shows the time course of the collector potentials of the wire-wound drive transistors, and 80a, 80b, and 80c indicate the collector potentials of the wire-wound drive transistors 3a, 3b, and 3c, respectively. Here, only the winding 2c is energized at time t=0 (at that time, the potential of 80c is low), and at t= _ts , it is released, and the rotor starts automatically and gradually increases the rotation. shows. Figure 6 b, c, and d are time-integrating capacitors 33, respectively.
This is the transition of voltages corresponding to so-called position signals of capacitors c, 33a, and 33b, where voltages e _c , e _a , and e _d are given as initial values to each capacitor (from t=0 to t=t _s ). Further, FIG. 6e shows a position signal (for example, a base current of a winding drive transistor) in which the voltage accumulated in the time-integrating capacitors 33a, 33b, and 33c is smoothly switched by the differential switching circuit 35; 81
b, 81c are finally windings 2a, 2b,
This corresponds to the current of 2c. Note that time t=
From 0 to t= _ts , only the winding 2c is forcibly energized as described above. As a result, the rotor will be positioned during that time, but in terms of the relative position of the rotor and the windings, at time t = t _s , one of the magnetic poles of the permanent magnet rotor, the N pole and the S pole. The center of one of the predetermined magnetic poles is rotated and positioned to a position substantially opposing the center of the stator winding 2c. In the diagram showing the back electromotive force integral calculation shown in FIG. 3, this state corresponds to t=
The initial value corresponding to the time t _N and which should be applied to the time integration capacitors 33c, 33a, and 33b can be said to be the voltage at the time t=t _N in FIGS. 3b, c, and d.

FIG. 7 shows a specific embodiment of the present invention. In the figure, parts common to those in FIG. 5 are given the same numbers. 60
30a, 31a, 32 in FIG.
Corresponds to a. The same applies to 60b and 60c. These three conversion circuits 60a, 60b,
Since 60c is completely the same, only 60a will be explained. 61 is a diode, through which a constant current I ₀ approximately determined by the resistor 62 always flows.
Since the transistor 63 constitutes a current mirror circuit with the diode 61, it also operates to absorb the current of I ₀ . On the other hand, the value of resistor 64 is resistor 6
If the collector potential of the winding drive transistor 3a is equal to + _Vcc , then the resistor 6
The current flowing through 4 is equal to I ₀ and therefore the shunt current to diode 68 is zero. Next, when the collector potential of the winding drive transistor 3a becomes lower than + _Vcc , the current flowing through the resistor 64 becomes less than _I0 , and the shunt current to the diode 68 becomes zero. On the other hand, the collector potential of the winding drive transistor 3a is +
When it becomes higher than _Vcc (assuming that ΔV becomes higher), the current flowing through the resistor 64 increases from _I0 . The increase is equal to ΔV divided by the resistance value of resistor 64, and this amount is shunted to diode 68. Therefore, the current shunted to the diode 68 is a half-wave rectified back electromotive force converted into a current, so the circuit section composed of 61, 62, 63, and 64 is a half-wave rectifier circuit and a voltage-current converter circuit. Also serves as Next, the transistors 69 and 70 form a current mirror circuit with the diode 68.
It attracts the same current as the shunt current. The collector of the transistor 70 is the charge/discharge integrating capacitor 3
3b, it will be discharged, and therefore the transistor 70 will become an attraction type current source. On the other hand, the collector of transistor 69 is connected to diode 71, and since diode 71 and transistor 72 constitute a current mirror circuit, transistor 72 discharges the same current as the shunt current of diode 68. Further, since the collector of the transistor 72 is connected to the charging/discharging integrating capacitor 33c, this is charged, and therefore the transistor 72 becomes a discharge type current source. Note that the resistor 73 is a relatively small resistor, which slightly lowers the gain of the current mirror circuit made up of the diode 71 and the transistor 72, and as a result, the amount of current discharged from the transistor 72 is made slightly smaller than the amount of shunt current from the diode 68. There is.

22 is a self-starting circuit, 24a, 24b,
Reference numeral 24c denotes a transfer switch made of a transistor, which is conductive only for a short period of time at the time of startup, and provides initial values to the time integration capacitors 33a, 33b, and 33c. Transistors 14a, 14b,
14c connects the switch transistors 24a, 24 via resistors 15a, 15b, 15c, respectively.
This is a transistor for driving a switch transistor connected to the bases of transistors b and 24c. Their bases are commonly connected, and a positive pulse with a short time width τ ₀ is applied to the base terminal 83 at startup. Now, at startup, the time integration capacitors 33a, 33b, 3
3c, the voltage values e _a , e _b , respectively to be transferred to
In this specific embodiment, the DC current having e _c is obtained by resistor-dividing the DC power supply + _Vcc and the DC voltage bias 34. That is, the voltage value e _a is created by resistor division by resistors 16a and 17a, the voltage value e _b by resistors 16b and 17b, and the voltage value e _c by resistors 16c and 17c. The resistor should have a relatively low value and should have a low output impedance. Note that the above DC voltage bias 34
has a sufficiently low output impedance and +V _cc
The voltage must be lower than that of the

Next, 25b and 25c are transistor-based switches, which are used to position the permanent magnet rotor by interrupting only a short period of time during startup. Next, the transistors 26b and 26c are connected to the resistor 27.
This is a switch transistor driving transistor connected to the bases of the switch transistors 25b and 25c via terminals b and 27c, respectively. The transistors 26b and 26c are driven via an inverter transistor 28. Note that the base of this inverter transistor 28 is connected to the switch transistor drive transistors 14a, 14.
Since the bases of the switch transistors 25b and 14c are connected in common and the positive pulse at the time of startup is applied from the base terminal 83, the switch transistors 25b and 25c are cut off only at the time of startup, and finally, during this period, the stator winding Only line 2c is energized.

The positive pulse is normally applied at the same time as the DC power supply + _Vcc is applied, but may be applied simultaneously with the application of the winding drive command 37.

FIG. 8 is a conceptual diagram of a restart method added to further improve the present invention. The above-mentioned self-starting method can be expected to achieve almost complete self-starting, but if the rotor is forcibly stopped by an external force while it is rotating, leakage current in the time-integrating capacitor may occur. As the location information is lost over time, it may become impossible to restart the device. Therefore, there is a detection circuit that detects the magnitude of the back electromotive force in the winding, a circuit that measures the time when the magnitude of the back electromotive force is below a certain predetermined level, and a circuit that restarts when the above-mentioned time exceeds a certain predetermined time. The restart circuit is composed of a circuit that outputs a signal. The drawings will be explained below. 75 is a detection circuit that detects the magnitude of the back electromotive force of the winding; 76 is a time measurement circuit that measures the time during which the magnitude of the back electromotive force is below a certain predetermined level; and 77 is a predetermined time period in which the above-mentioned time is present. This circuit outputs a restart signal when the self-start circuit 22 exceeds 0, and this restart signal is a positive pulse having a time width τ ₀ applied to the common base terminal 83 of the self-start circuit 22 shown in FIG. With this configuration, a restart signal is issued after a certain period of time has passed after the electric motor stops rotating, and this signal triggers the self-start circuit 22 again to urge the motor to restart. Further, this restart signal is repeatedly given at predetermined time intervals until the motor is started. Therefore, this can be guaranteed even if the first self-startup fails.

FIG. 9 shows a specific embodiment of a restart circuit using the above-mentioned restart method. To explain this, the transistors 84a, 84b, and 84c detect the level of the back electromotive force of the windings, and their emitters connect the windings 2a, 84c through the resistors 85a, 85b, and 85c, respectively.
2b and 2c, and when the back electromotive force becomes higher than the power supply voltage +V _cc by the emitter-base junction potential difference V _EB , conduction occurs and a current flows. transistor 8
The collectors of 4a, 84b, and 84c are commonly connected, and the detected currents are added and applied to the base of reset transistor 86. Therefore, the peak value of the back electromotive force of the winding of the reset transistor 86 is V _EB
If it becomes larger, it will turn on and off periodically. _VEB
If it is smaller, it remains OFF. Reset transistor 86 is then connected to reset time measurement capacitor 87. In addition, the capacitor 87 is connected to the power supply voltage +V _cc through the charging resistor 88.
It is constantly charged. Therefore, if the back electromotive force of the winding is smaller than _VEB , the reset transistor 86
remains OFF, so the time measurement capacitor 8
7's charging progresses and its potential rises. 89 is a comparator that compares E _s of the comparison voltage 90 with the potential across the capacitor 87, and when the capacitor 87 is charged and exceeds E _s after a predetermined time, its output changes from a high state to a low state. Changes to A one-shot pulse circuit 91 generates a one-shot positive pulse having a time width τ ₀ in response to a change in the state of the output of the comparator 89.
This positive pulse corresponds to the positive pulse of a short time width τ ₀ given to the self-starting circuit 22 at the time of startup described above, and is given to the common base terminal 83 in FIG. Reference numeral 92 is a trigger input terminal for triggering a one-shot pulse for initial startup, such as when a DC power supply + _Vcc is applied. Next, the resistor 93 is used to return the one-shot positive pulse to the base of the reset transistor 86, and is a feedback resistor to enable the one-shot positive pulse to be generated repeatedly at predetermined time intervals if the motor still does not start. .

In the embodiment of the restart circuit shown in FIG. 9, the V _EB of the transistor is used to detect the magnitude of the back electromotive force, but there are several other methods. For example, the determination may be made based on the amount of discharge current or suction current of the voltage-current conversion circuit for the back electromotive force of the winding shown in FIG. 5.
This current is obtained by converting the back electromotive force of the winding into a current, so for example, you can compare this current amount with a separately provided reference current, or you can flow it into a resistor and compare it with the voltage generated across it and the reference current. You may also compare the voltages. In this case, the standard can be set freely, so it may be more convenient than using the V _EB of the transistor.

In addition, the circuit that measures the time during which the magnitude of the back electromotive force is below a predetermined level relies on a time measuring capacitor 87, a charging resistor 88, and a comparator 89 in this embodiment, but in short, this circuit is a type of delay timer. Any other device may be used as long as it performs the same function, and is not necessarily limited to this embodiment.

By configuring the restart circuit as described above, if a predetermined period of time has elapsed with the back electromotive force below a predetermined level, it is determined that the motor rotation has stopped, and a restart signal is generated. Therefore, the self-starting circuit can be operated again to restart the electric motor. This restart circuit guarantees even if the initial self-start fails due to any cause, so adding this restart circuit will greatly increase the reliability regarding startup.

As explained above, according to the present invention, the self-starting method reduces the self-starting time and ensures self-starting, and the restarting method guarantees against forced rotation stop due to external force or initial self-starting failure. As a result, it is possible to realize a motor that is comparable to conventional brushless motors in which the rotor position is directly recognized using a detection element such as a Hall element.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram of a motor and a winding drive transistor according to the present invention, Fig. 2 is a waveform diagram showing the collector potential of the winding drive transistor of the motor shown in Fig. 1, and Fig. 3 is an integral of back electromotive force. Figure 4 is a waveform diagram showing the state of calculation, Figure 4 is a waveform diagram of a position signal that smoothly switches through the three differential circuits, Figure 5 is a block diagram showing an embodiment of the present invention, Figure 6 is the activation of the present invention. 7 is a circuit diagram showing a specific embodiment of the present invention, FIG. 8 is a block diagram of a restart method added to improve the present invention, and FIG. 9 is a waveform diagram illustrating the process at the time of operation. FIG. 2 is a circuit diagram showing a specific example of a restart method. 1...Permanent magnet rotor, 2a, 2b, 2c...
Stator winding, 3a, 3b, 3c... Winding drive transistor, 22... Self-starting circuit, 24a, 24
b, 24c...Start switch, 25b, 25c...
...Positioning switch, 33a, 33b, 33c...
...Charge/discharge time integral capacitor, 60a, 60b,
60c...Discharge type and suction type voltage current conversion circuit,
75... Winding back electromotive force detection circuit, 76... A circuit that measures the time during which the magnitude of the back electromotive force is below a certain predetermined level, 77... Restart signal output circuit.

Claims (1)

[Scope of Claims] 1. A rectifier circuit that individually extracts all or part of the non-current-carrying region of the back electromotive force generated in each of a plurality of stator windings, and a discharge circuit that converts the output of the rectifier circuit into a current, respectively. The battery is charged and discharged by a type voltage-current conversion circuit, a suction-type voltage-current conversion circuit that converts the output of the rectifier circuit into a current, and a discharge-type voltage-current conversion circuit and a suction-type voltage-current conversion circuit. The present invention has an arithmetic circuit composed of a plurality of time-integrating capacitors, and the arithmetic circuit individually extracts all or part of the non-energized region of the back electromotive force generated in each of the plurality of stator windings. The result of temporal addition and subtraction integration and integral calculation is used as the rotational position signal of the permanent magnet rotor.
A plurality of stator winding drive circuits which are sequentially energized by this signal, a plurality of power supplies to provide an initial integral value, a plurality of switch means for transferring this to the time integration capacitor, and the switch means are made conductive at the time of startup. What is claimed is: 1. A brushless electric motor comprising: a self-starting circuit that is constituted by an electronic circuit and provides an initial integration value to the plurality of time-integrating capacitors at the time of starting. 2. The self-starting circuit according to claim 1, wherein the self-starting circuit includes an electronic circuit that energizes only a specific stator winding phase at the time of starting and positions the permanent magnet rotor in advance. Brushless electric motor. 3. A rectifier circuit that individually takes out all or a part of the non-energized region of the back electromotive force generated in each of the plurality of stator windings, and a discharge type voltage-current conversion circuit that converts the output of the rectifier circuit into a current, respectively. a suction-type voltage-current conversion circuit that converts the output of the rectifier circuit into a current, and a plurality of time-integrating capacitors that are charged and discharged by the discharge-type voltage-current conversion circuit and the suction-type voltage-current conversion circuit. The arithmetic circuit is configured to individually extract all or part of the non-energized region of the back electromotive force generated in each of the plurality of stator windings, and perform temporal summation, integration, and The result of subtraction integration and integral calculation is used as the rotational position signal of the permanent magnet rotor.
A plurality of stator winding drive circuits which are sequentially energized by this signal, a plurality of power supplies to provide an initial integral value, a plurality of switch means for transferring this to the time integration capacitor, and the switch means are made conductive at the time of startup. A self-starting circuit that is composed of an electronic circuit and gives an initial integration value to the plurality of time-integrating capacitors at startup, a rectifier circuit that takes out the back electromotive force, and a time period during which the magnitude thereof is below a predetermined level. and a restart circuit configured of a circuit that detects when the above-mentioned time exceeds a certain predetermined time and outputs a restart signal, and the self-start circuit is also configured by the restart signal of the restart circuit. A brushless electric motor characterized by being able to operate.