JPH0731185A - Controller for brushless motor - Google Patents

Abstract

PURPOSE:To ensure stability and reliability when a brushless motor is started by a sensorless system. CONSTITUTION:A sensorless system drive circuit 1 for a brushless motor is provided with a first voltage generating circuit 17 generating a voltage increasing functionally from zero, a second voltage generating circuit 18 generating a voltage decreasing functionally from a constant level or a set level, and a comparing circuit 19 for comparing the voltages from the first and second voltage generating circuits 17, 18 and resetting the first circuit 17 when the voltage therefrom exceeds that from the second circuit 18. The drive circuit 1 is also provided with a starting circuit 2 including a counter for counting the outputs from the comparing circuit 19 and delivering a reset signal to the first and second circuits 17, 18 when a predetermined count is reached. When a brushless motor is started, transistors 6-9 are operated by the output from the comparing circuit 19 in the starting circuit 2 through the drive circuit 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starting circuit in a control circuit of a brushless motor for detecting a relative position between a stator coil and a magnet rotor from a counter electromotive voltage of the stator coil to drive the brushless motor.

[0002]

2. Description of the Related Art As a conventional control circuit for a brushless motor, there is, for example, one disclosed in JP-A-62-281791. This is a three-phase full-wave drive system, in which the Hall element detects the magnetic flux of the magnet rotor, the position detection circuit inputs a three-phase position detection signal to the logic processing circuit, and the switching element is controlled to control the brushless motor. Drive control.

Further, as disclosed in Japanese Patent Application Laid-Open No. 4-161092, the relative position between the stator coil and the magnet rotor is detected by the induced voltage of the stator coil without using a position sensor such as a Hall element. There is also a sensorless type control circuit that controls the switching element based on this and drives and controls the brushless motor.

[0004]

In the conventional control circuit for a brushless motor as described above, the former is difficult to downsize and the cost is reduced due to the hall element and the wiring associated therewith. It is moving to a sensorless system. However, in the sensorless method, the start-up tends to be unstable, and for example, the above-mentioned Japanese Patent Laid-Open No.
In Japanese Patent Laid-Open No. 161092, the capacitor is charged and discharged to alternately energize and shake it to start. And, to prevent malfunctions caused by noise when the switch is turned on, the power is cut off during that time.
There are still challenges to the stability and reliability of startup.

The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to obtain stability and certainty of starting in a control circuit of a sensorless type brushless motor.

[0006]

According to a first aspect of the present invention, there is provided a brushless motor control device including a first voltage generating circuit for generating a voltage functionally increasing from zero in a sensorless brushless motor drive circuit. A second voltage generating circuit that generates a constant voltage or a voltage that functionally gradually decreases from a set voltage value is compared with the voltages of the first voltage generating circuit and the second voltage generating circuit to generate the first voltage. A comparison circuit that resets the first voltage generation circuit when the voltage of the circuit exceeds the voltage of the second voltage generation circuit, and a first voltage generation circuit that counts the output of this comparison circuit and that reaches a predetermined number of times. A starting circuit including a counter for outputting a reset signal is provided in the second voltage generating circuit, and at the time of starting, the semiconductor element is operated via the drive circuit by the output of the comparison circuit of this starting circuit.

A brushless motor control device according to a second aspect of the present invention is a first voltage generation circuit for varying a terminal voltage of a capacitor in a sensorless type brushless motor drive circuit by energizing a capacitor by a constant current source. And a second voltage generating circuit that generates a constant voltage by resistance division, and the voltages of the first voltage generating circuit and the second voltage generating circuit are compared, and the voltage of the first voltage generating circuit is the second voltage. A comparison circuit that resets the first voltage generation circuit when the voltage of the generation circuit is exceeded, and counts the output of this comparison circuit and resets the first voltage generation circuit and the second voltage generation circuit when the output reaches a predetermined number of times. A starting circuit including a counter for outputting a signal is provided, and the semiconductor element is operated via the drive circuit by the output of the comparison circuit of the starting circuit at the time of starting.

A brushless motor control device according to a third aspect of the present invention is the control device for the brushless motor according to the first aspect, wherein the first voltage generating circuit is connected to a capacitor with a resistor to control the terminal voltage of the capacitor. The second voltage generating circuit has a circuit configuration in which a capacitor is energized to control the terminal voltage.

According to a fourth aspect of the present invention, there is provided a brushless motor control device according to the first aspect, wherein the first voltage generating circuit has a circuit configuration for energizing a capacitor by a constant current source to control the terminal voltage thereof. The second voltage generating circuit has a circuit configuration in which a capacitor is energized by a constant current source to control its terminal voltage.

According to a fifth aspect of the present invention, there is provided a brushless motor control device according to the first aspect, wherein the first voltage generating circuit has a circuit configuration for controlling a terminal voltage of the capacitor by connecting a resistor to the capacitor. The second voltage generating circuit has a circuit configuration in which a capacitor is energized by a constant current source to control its terminal voltage.

According to a sixth aspect of the present invention, there is provided a brushless motor control device according to the first aspect, wherein the first voltage generating circuit has a circuit configuration in which a capacitor is energized by a constant current source to control its terminal voltage. The voltage generation circuit of No. 2 has a circuit configuration in which a resistor is connected to the capacitor to control the terminal voltage of the capacitor.

A brushless motor controller according to a seventh aspect of the present invention is the control device for a brushless motor according to the first aspect, wherein the first voltage generating circuit, the second voltage generating circuit and the comparing circuit are provided with an oscillator and a digital signal for counting the waveform thereof. It is composed of a counter and a comparator.

[0013]

According to the present invention, the voltages of the first voltage generating circuit and the second voltage generating circuit are compared by the comparator, and the voltage of the first voltage generating circuit is compared with the voltage of the second voltage generating circuit. When the voltage exceeds the voltage, the first voltage generating circuit is reset, so that the frequency of the rotating magnetic field formed by the output of the comparison circuit gradually increases with the passage of time.

According to the second aspect of the present invention, in particular, a first voltage generating circuit for varying the terminal voltage of the capacitor by energizing the capacitor with a constant current source, and a second voltage generating circuit for generating a constant voltage by resistance division. The voltage of the voltage generating circuit is compared by the comparator, and when the voltage of the first voltage generating circuit exceeds the voltage of the second voltage generating circuit, the first voltage generating circuit is reset. The frequency of the rotating magnetic field formed linearly gradually increases from the bottom, and the gradient of the linear change in frequency can be easily changed depending on the magnitude of the load.

According to the third aspect of the invention, in particular, the first voltage generating circuit is a circuit configuration for controlling the terminal voltage of the capacitor by connecting the resistor to the capacitor, and the second voltage generating circuit is the capacitor. Because of the circuit configuration that energizes and controls the terminal voltage, the frequency of the rotating magnetic field formed by the output of the comparator that compares and outputs these voltages is non-linear that is drawn into synchronous rotation over a relatively long time after starting. Gradually increase gradually.

In a fourth aspect of the present invention, in particular, the first voltage generating circuit has a circuit configuration in which a constant current source supplies electricity to the capacitor to control the terminal voltage thereof, and the second voltage generating circuit uses the constant current source to convert the capacitor. Because of the circuit configuration that energizes and controls the terminal voltage, the frequency of the rotating magnetic field formed by the output of the comparator that compares and outputs these voltages is non-linear that is drawn into synchronous rotation over a relatively long time after starting. Gradually increase gradually.

In a fifth aspect of the present invention, particularly, the first voltage generating circuit has a circuit configuration in which a resistor is connected to the capacitor to control the terminal voltage of the capacitor, and the second voltage generating circuit is a constant current. The frequency of the rotating magnetic field formed by the output of the comparator, which compares these voltages and outputs them, is a synchronous rotation that takes a relatively long time after starting. It will gradually increase in a non-linear fashion.

In a sixth aspect of the invention, in particular, the first voltage generating circuit has a circuit configuration in which a constant current source energizes a capacitor to control the terminal voltage thereof, and the second voltage generating circuit connects a resistor to the capacitor. Since this is a circuit configuration that controls the terminal voltage of the capacitor, the frequency of the rotating magnetic field formed by the output of the comparator that compares and outputs these voltages is relatively steep and nonlinear after starting. Will gradually increase.

According to a seventh aspect of the invention, in particular, the first voltage generating circuit, the second voltage generating circuit and the comparing circuit are constituted by an oscillator, a digital counter for counting the waveform thereof, and a comparator. Therefore, it becomes easy to set the change of the frequency of the rotating magnetic field formed by the output of the comparator over time.

[0020]

1 is a circuit diagram of a control circuit for a brushless motor of a two-phase sensorless system, which is an embodiment of the present invention, and comprises a drive circuit 1 and a starting circuit 2. In the drive circuit 1, 3 and 4 are stator coils of each phase of the brushless motor, which together with a magnet rotor (not shown) constitute a motor body of the brushless motor. Reference numeral 5 denotes a semiconductor drive signal output circuit, which outputs a conduction cutoff control output to four switching transistors 6, 7, 8 and 9 which form a phase arm by a flip-flop circuit and a logic circuit. Reference numeral 10 denotes a positive power source connected to the emitters of the upper transistors 6 and 7 and the lower transistors 8 and 9 configured in the H bridge.
It is an intermediate power source of the negative power source connected to the emitter of and is connected to the common connection terminal of the stator coils 3 and 4.
A position detection circuit 11 detects the relative position of the magnet rotor from the counter electromotive voltages of the stator coil 3 and the stator coil 4, and outputs it to the semiconductor drive signal output circuit 5.

In the starting circuit 2, 12 is an oscillator which outputs a constant output pulse, and 13 is a counter which operates and counts the output pulse of the oscillator 12 by a starting start signal 14. Reference numeral 15 is a frequency sweep start signal 1 after a predetermined time has elapsed after the counter 13 has counted the predetermined pulses.
6 is a start signal output circuit that outputs 6 (a signal that means to start gradually increasing the frequency of the rotating magnetic field). Reference numerals 17 and 18 are a first voltage generating circuit and a second voltage generating circuit whose voltage is changed from the initial state by the frequency sweep start signal 16 from the start signal output circuit 15. The first voltage generating circuit 17 generates a voltage that functionally rises from zero. Further, the second voltage generating circuit 18 generates a constant voltage or a voltage which is functionally gradually reduced from a set voltage value. 19 is the first voltage generation circuit 1
7 and the voltage of the second voltage generation circuit 18 and outputs a square wave according to the magnitude of the difference. The output has a waveform as shown in FIG. It is input to the drive signal output circuit 5 and the counter 20 of the starting circuit 2. The counter 20 counts the output of the comparison circuit 19, counts the set number of square waves, and then outputs a reset signal. This reset signal is input to the first voltage generation circuit 17 and the second voltage generation circuit 18, resets them to the initial state, and is also input to the semiconductor drive signal output circuit 5, and the semiconductor drive signal output circuit 5 Is switched to operate according to the output of the position detection circuit 11.

In the control circuit having the above structure, the drive circuit 1
Is the logic from the semiconductor drive signal output circuit 5,
The transistors 6, 7, 8 and 9 of each phase arm are sequentially turned on to energize the stator coil 3 and the stator coil 4 to rotate the brushless motor. That is, the transistor 6 is turned on by the base signal, a current flows from the high potential side to the medium potential side in the stator coil 3, and the transistor 6 is turned off after 90 degrees of phase conduction. Next, the transistor 7 is turned on by the base signal, and the stator coil 4
A current flows from the high potential side to the medium potential side, and the transistor 7 is turned off after 90 degrees of phase conduction. Subsequently, the transistor 8 is turned on by the base signal, a current flows from the medium potential side to the low potential side in the stator coil 3, and the transistor 8 is turned off after 90 degrees of phase conduction. Further, the transistor 9 is turned on by the base signal, a current flows through the stator coil 4 from the medium potential side to the low potential side, and the transistor 9 is energized by 90 degrees in phase,
Turns off. Thereafter, by repeating this series of operations, a rotating magnetic field is generated in a fixed direction, and the brushless motor rotates.

The position detection circuit 11 detects the position of the magnet rotor by the counter electromotive voltage generated in the stator coil 3 and the stator coil 4 when the motor is driven, and sends a signal to the semiconductor drive signal output circuit 5. Semiconductor drive signal output circuit 5
Processes this signal and determines the energization switching timing by the base signals of the transistors 6, 7, 8 and 9. Since the counter electromotive voltage is not generated in the stator coil 3 and the stator coil 4 at the start of starting, the position detection circuit 11 cannot detect the proper position of the magnet rotor. Therefore, at the time of start-up, a signal from the start-up circuit 2 is sent to the semiconductor drive signal output circuit 5 instead of the position detection circuit 11 to be processed into a drive signal as shown in FIG. To start.

The start-up circuit 2 outputs a signal that changes in the synchronous pull-in frequency band of the brushless motor, and the transistors 6, 7, through the semiconductor drive signal output circuit 5.
8 and 9 are controlled to generate a rotating magnetic field in which the frequency for starting changes gradually with time. Hereinafter, some specific examples of the starting circuit 2 will be described.

<Specific Example 1 of Startup Circuit> The first voltage generation circuit 17, the second voltage generation circuit 18, and the comparison circuit 19 of the startup circuit have a circuit configuration as shown in FIG. In FIG. 4, reference numeral 21 is a power supply for the first voltage generating circuit 17,
3 is a PNP transistor of current mirror configuration, 24,
25 is also a PNP transistor having a current mirror configuration. 26, 27, 28 are NPN transistors, 29, 3
0, 31, 32 are resistors. 33 and 34 are capacitors, a and b are input terminals and output terminals of the first voltage generation circuit 17, and the input terminal a is the base of the NPN transistor 26 via the resistor 29 and the base of the NPN transistor 27 via the resistor 30. It is connected to the. Output terminal b is PN
It is a connection point between the collector of the P-transistor 25 and the capacitor 34.

In the second voltage generating circuit 18, 35,
Reference numeral 36 is a resistor connected in series to the power source 21, and the output terminal d of the second voltage generating circuit 18 is connected to the voltage dividing point thereof. The input terminal of the second voltage generation circuit 18 is not necessary because the comparison voltage is generated only by the resistance voltage division.

In the comparison circuit 19, reference numeral 37 in the drawing is an open collector type comparator, and the first voltage generation circuit 17
And the output of the second voltage generation circuit 18 are input. 38 is a power supply for the comparison circuit. 39, 40, 4
1 is an NPN transistor, 42, 43, 44, 45, 4
Reference numerals 6, 47, and 48 are resistors, and the output of the comparator 37 is input to the semiconductor drive signal output circuit 5 and the counter 20 as the output of the comparison circuit 19.

In the starting circuit 2, when the frequency sweep start signal 16 is input to the input terminal a of the first voltage generating circuit 17, the NPN transistor 26 is turned off and the constant current determined by the resistor 31 is applied to the PNP transistor. 22 flows from the power supply 21. Since the PNP transistor 22 and the PNP transistor 23 have a current mirror configuration,
The same current as the current flowing through the PNP transistor 22 is P
The current flows to the collector of the NP transistor 23, which charges the capacitor 33. The terminal voltage rises linearly. The NPN transistor 28 is this capacitor 33.
The terminal voltage of is received at the base and converted into a current by the resistor 32. In the PNP transistor 24 and the PNP transistor 25 of the current mirror configuration connected to the NPN transistor 28, the same current as the current flowing in the PNP transistor 24 flows in the collector of the PNP transistor 25. As a result, the capacitor 34 is charged. This voltage rises quadratically. This voltage is output from the output terminal b to the comparator 37.

On the other hand, a voltage obtained by dividing the power supply 21 by the resistors 35 and 36 is generated at the output terminal d of the second voltage generating circuit 18, and is input to the other input terminal of the comparator 37 via the resistor 42. To be done. The comparator 37 is the first voltage generation circuit 1
At the same time that the output voltage of 7 exceeds the output voltage of the second voltage generating circuit 18, the output is inverted and the open state is almost changed to the ground state. When the output of the comparator 37 becomes the ground state, the NPN transistor 39 is turned off and the NPN transistors 40 and 41 are turned on. When the NPN transistor 40 is turned on, one input of the comparator 37 drops to a voltage obtained by dividing the output of the output terminal d of the second voltage generating circuit 18 by the resistors 42 and 43. When the NPN transistor 41 is turned on, the first voltage generating circuit 17 is connected via the resistor 48.
The electric charge of the capacitor 34 connected to the output terminal b of is discharged. The resistor 48 functions to limit the peak current and delay the voltage drop at the output terminal b from the output terminal d.

When the potential of the output terminal b of the first voltage generating circuit 17 falls below the potential of the output terminal d of the second voltage generating circuit 18, the output of the comparator 37 is inverted and the open state is established. Then, the NPN transistor 39 is turned on and the NPN transistor 39 is turned on.
The transistors 40 and 41 are turned off. When the NPN transistor 40 is turned off, the potential of one of the input terminals of the comparator 37 again rises to the potential of the output terminal d and returns. When the NPN transistor 41 is turned off, the capacitor 34 is charged again with the linearly increasing current, and the voltage of the output terminal b of the first voltage generating circuit 17 increases. Thereafter, this operation is repeated.

A counter 20 which receives the output of the comparator 37
When the output pulse of the comparator 37 is counted a predetermined number of times, the reset signal is output, the NPN transistors 26 and 27 of the first voltage generating circuit 17 are turned off, and the capacitor 3
The voltage of 3, 34 is held at zero. Thus, voltage waveforms as shown in FIG. 5 are generated at the output terminals b and d. Further, the semiconductor drive signal output circuit 5 receiving the output of the comparator 37, while the reset signal from the counter 20 is not inputted,
The output of the comparator 37 is signal-processed to process the transistors 6 and 6.
Controlling 7, 8 and 9 to form a rotating magnetic field for activation,
Start the brushless motor.

In the above-mentioned start-up circuit 2, the frequency of the rotating magnetic field that linearly rises with the passage of time as shown by A in FIG. 6 is obtained, and the capacitor 3
Brushless motors having different loads can be smoothly and reliably started only by changing the capacities of 3, 34.

<Specific Example 2 of Starting Circuit> In this specific example, the first voltage generating circuit 17 and the second voltage generating circuit 18 of the starting circuit 2 have a circuit configuration as shown in FIG. The structure is the same as that shown in FIG. That is, as shown in FIG. 7, the first voltage generating circuit 17 is composed of an NPN transistor 49, a resistor 50 and a capacitor 51 connected in series to the power supply 21. On the other hand, the second voltage generating circuit 18 includes a PNP transistor 52, a capacitor 53 and a voltage dividing resistor 54, which are connected in series to the power source 21.
It is composed of 55. The input terminal a of the first voltage generating circuit 17 is connected to the base of the NPN transistor 49, and the output terminal b is the connection point of the resistor 50 and the capacitor 51. The input terminal c of the second voltage generating circuit 18 is P
It is connected to the base of the NP transistor 52, and the output terminal d
Is a common connection point of the resistors 54 and 55 and the capacitor 53.

In the above circuit configuration, when the frequency sweep start signal 16 is input to the input terminal a of the first voltage generating circuit 17 and the input terminal c of the second voltage generating circuit 18, the NPN transistor 49 and the PNP transistor are input. 52
Turns off from on. Since one is the NPN transistor 49 and the other is the PNP transistor 52, an interface is required to turn on / off the same frequency sweep start signal 16. When the NPN transistor 49 of the first voltage generating circuit 17 is turned off, the capacitor 51 is charged through the resistor 50, and the voltage of the output terminal b goes from the ground to the power source 21 through the resistor 5.
It rises exponentially with a time constant determined by 0 and the capacitor 51. When the PNP transistor 52 of the second voltage generating circuit 18 is turned off, the voltage of the output terminal d is an exponential function with a time constant determined by the capacitor 53 and the resistors 54 and 55 from the power source 21 toward the voltage division of the resistors 54 and 55. Decrease. These are input to the comparison circuit 19, a rotating magnetic field for starting is formed by the same operation as in the first specific example, and the brushless motor is started. Output terminals b and d of this specific example 2
The voltage waveform of is as shown in FIG. 8, and the frequency of the rotating magnetic field is a low frequency that is drawn from the start to the synchronous rotation for a relatively long time as shown in B of FIG. As a result, when the magnet rotor of the brushless motor and, for example, the blades attached to the magnet rotor are heavy and the moment of inertia is large and it takes a long time to start, the start can be reliably performed without step-out.

<Specific Example 3 of Starting Circuit> In this specific example, the first voltage generating circuit 17 and the second voltage generating circuit 18 of the starting circuit 2 have a circuit configuration as shown in FIG. The configuration is the same as that shown in FIG. 1 or that of the second specific example, and the description of the same components will be omitted by giving the same reference numerals to the drawings. That is, as shown in FIG. 9, the first voltage generating circuit 17 is composed of an NPN transistor 56, PNP transistors 57 and 58 of a current mirror configuration, a resistor 59 and a capacitor 60. On the other hand, the second voltage generating circuit 18 includes a PNP transistor 61, NPN transistors 62 and 63 having a current mirror configuration, a diode 64, a capacitor 65, and resistors 66, 67 and 68. Input terminal a of the first voltage generating circuit 17
Is connected to the base of the NPN transistor 56, and the output terminal b is a common connection point of the collector of the NPN transistor 56, the collector of the PNP transistor 58, and the capacitor 60. The input terminal c of the second voltage generating circuit 18 is connected to the base of the PNP transistor 61, and the output terminal d is a common connection point of the collector of the NPN transistor 62, the diode 64 and the capacitor 65.

In the above circuit configuration, when the frequency sweep start signal 16 is input to the input terminal a of the first voltage generating circuit 17 and the input terminal c of the second voltage generating circuit 18, the NPN transistor 56 and the PNP transistor are input. 61
Turns off from on. N of the first voltage generation circuit 17
When the PN transistor 56 is turned off, a current determined by the resistor 59 flows to the PNP transistor 57, the same current also flows to the collector of the PNP transistor 58, and the capacitor 60 is charged. Since the capacitor 60 is charged with a constant current, its terminal voltage increases linearly from the ground toward the power supply 21.

When the PNP transistor 61 of the second voltage generating circuit 18 is turned off, a current determined by the resistor 68 flows through the NPN transistor 63 and the NPN transistor 6
The same current flows through the collector of 2 and the capacitor 65
Is discharged from the power source 21 toward the potential obtained by subtracting the voltage drop of the diode 64 from the voltage divided by the resistors 66 and 67. Since the capacitor 65 is discharged with a constant current, the potential drops linearly. These are input to the comparison circuit 19, a rotating magnetic field for starting is formed by the same operation as in the second specific example, and the brushless motor is started. The voltage waveforms at the output terminals b and d of this specific example 3 are as shown in FIG. 10, and the frequency of the rotating magnetic field is a low frequency that is drawn from the start to the synchronous rotation for a relatively long time as shown in B of FIG. As a result, when the magnet rotor of the brushless motor and, for example, the blades attached to the magnet rotor are heavy and the moment of inertia is large and it takes a long time to start, the start can be reliably performed without step-out.

<Specific Example 4 of Starting Circuit> In this specific example, the first voltage generating circuit 17 and the second voltage generating circuit 18 of the starting circuit 2 have a circuit configuration as shown in FIG. The configuration is the same as in the specific example 2 or the specific example 3, and the same components will be denoted by the same reference numerals in the drawings and will not be described.
That is, as shown in the figure, the first voltage generating circuit 17 is composed of an NPN transistor 49, a resistor 50 and a capacitor 51 which are connected in series to the power supply 21, as in the second specific example. Further, the second voltage generating circuit 18 has the same configuration as the PNP transistor 61 and the N of the current mirror configuration as in the third embodiment.
It is composed of PN transistors 62 and 63, a diode 64, a capacitor 65 and resistors 66, 67 and 68.

In the above circuit configuration, the combination of the first voltage generating circuit 17 of the second specific example and the second voltage generating circuit 18 of the third specific example produces a voltage waveform as shown in FIG. b and d, and these are generated in the comparison circuit 1
9, the rotating magnetic field for starting is formed by the same operation as in each of the above specific examples, and the brushless motor is started. The frequency of the rotating magnetic field according to the specific example 4 is B in FIG.
As described above, the frequency becomes low so that the synchronous rotation is drawn from the start for a relatively long time. As a result, when the magnet rotor of the brushless motor and the blades and the like attached to the brushless motor are heavy and the moment of inertia is large and it takes a long time to start, the start can be reliably performed without step-out.

<Fifth Specific Example of Starting Circuit> In this specific example, the first voltage generating circuit 17 and the second voltage generating circuit 18 of the starting circuit 2 have a circuit configuration as shown in FIG. The configuration is the same as in the specific example 2 or the specific examples 3 and 4, and the description of the same components will be omitted by attaching the same reference numerals to the drawings. That is, as shown in FIG. 13, the first voltage generation circuit 17
Is composed of an NPN transistor 56, PNP transistors 57 and 58 having a current mirror configuration, a resistor 59 and a capacitor 60, as in the third embodiment. Also,
The second voltage generating circuit 18 is composed of a PNP transistor 52, a capacitor 53, and resistors 54 and 55 for voltage division, which are connected in series to a power source 21 as in the second specific example.

In the above circuit configuration, a voltage waveform as shown in FIG. 14 is output from the combination of the first voltage generating circuit 17 of the third specific example and the second voltage generating circuit 18 of the second specific example. These are generated at the terminals b and d, and these are input to the comparison circuit 19, and a rotating magnetic field for starting is formed by the same operation as in each of the specific examples, and the brushless motor is started. The frequency of the rotating magnetic field according to the fifth specific example is increased in a relatively short time from the start as shown in C of FIG. Thus, the magnetless rotor of the brushless motor and, for example, the blades attached to the magnet rotor have a small weight and a small moment of inertia, so that the brushless motor can be started up smoothly and in a short time.

<Specific Example 6 of Starting Circuit> In this specific example, the first voltage generating circuit 17, the second voltage generating circuit 18, and the comparison circuit 19 of the starting circuit 2 have a circuit configuration as shown in FIG. The other configuration is the same as that shown in FIG. 1, and the description of the same components will be omitted. That is, as shown in FIG. 15, the first voltage generating circuit 17 is composed of an N-advance down counter 69, and the second voltage generating circuit 18 is connected to an oscillator 70.
And an N-ary up counter 71, and the respective outputs are input to the comparator 72. An arbitrary N value of the N-adic set signal is input to the N-adic down counter 69 in advance.

In the above circuit configuration, the start signal is N
When input to the advance / decrement counter 69, the N-advance up counter 71, and the comparator 72, the N-advance up counter 71 counts the clock of the oscillator 70 connected thereto. At this time, the output of the N-adic down counter 69 is
The value corresponding to the N value is input to the comparator 72 as the comparison input 1. The N-ary up counter 71 counts from zero, and the output is input to the comparator 72 as the comparison input 2. When the N-ary up counter 71 counts up and the comparison input 2 becomes the same as the comparison input 1, the output of the comparator 72 is inverted, a reset signal is generated in synchronization with this, and the N-ary up counter 71 is reset. It becomes zero. Furthermore N
A countdown instruction signal is generated to the advance down counter 69, whereby the N advance down counter 69 counts down by 1 and the comparison input 1 becomes the N value -1. At this time, since the comparison input 1 and the comparison input 2 are different, the comparator 72
Output returns to the initial state. When the N-ary up counter 71 counts up and the comparison input 2 becomes the comparison input N value -1, the output of the comparator 72 is inverted, and the above operation is repeated until the comparison input 2 becomes zero. The output of the comparator 72 is input to the semiconductor drive signal output circuit 5 shown in FIG. 1 to form a rotating magnetic field for starting. As a result, the brushless motor is smoothly started, and the comparator 72
It becomes easy to set the change of the frequency of the rotating magnetic field formed by the output of the.

Although the embodiment has been described based on the two-phase full-wave driving method, the three-phase driving method can be similarly applied.

[0045]

As is apparent from the above description of the embodiments, according to the first aspect of the invention, the first voltage generating circuit,
The voltage of the second voltage generating circuit is compared by the comparator, and when the voltage of the first voltage generating circuit exceeds the voltage of the second voltage generating circuit, the first voltage generating circuit is reset. The frequency of the rotating magnetic field formed by the output gradually increases with the passage of time, and the stability and certainty of starting the sensorless brushless motor can be obtained.

According to the second aspect of the present invention, the first voltage generating circuit for varying the terminal voltage of the capacitor by energizing the capacitor with the constant current source, and the second voltage generating circuit for generating a constant voltage by resistance division. The voltage of the first voltage generating circuit is compared with the voltage of the second voltage generating circuit by the comparator, and the first voltage generating circuit is reset when the voltage of the first voltage generating circuit exceeds the voltage of the second voltage generating circuit. The frequency of the rotating magnetic field formed by is linearly gradually increased from the bottom, and the gradient of the linear change of the frequency can be easily changed according to the magnitude of the load, and the adaptability is improved.

According to the third aspect of the present invention, in particular, the first voltage generating circuit has a circuit configuration in which a resistor is connected to the capacitor to control the terminal voltage of the capacitor, and the second voltage generating circuit is the capacitor. The frequency of the rotating magnetic field formed by the output of the comparator, which compares and outputs these voltages, takes a relatively long time from the start to the non-synchronous rotation. It gradually increases linearly, and the stability and certainty of starting of the sensorless brushless motor, which has a large moment of inertia and takes a long time to start, can be obtained.

According to the fourth aspect of the present invention, in particular, the first voltage generating circuit has a circuit configuration in which the constant current source energizes the capacitor to control the terminal voltage thereof, and the second voltage generating circuit uses the constant current source for the capacitor. The frequency of the rotating magnetic field formed by the output of the comparator, which compares and outputs these voltages, takes a relatively long time from the start to the non-synchronous rotation. It gradually increases linearly, and the stability and certainty of starting of the sensorless brushless motor, which has a large moment of inertia and takes a long time to start, can be obtained.

According to the fifth aspect of the present invention, in particular, the first voltage generating circuit has a circuit configuration in which a resistor is connected to the capacitor to control the terminal voltage of the capacitor, and the second voltage generating circuit is constant. Since the circuit configuration controls the terminal voltage by energizing the capacitor with a current source, the frequency of the rotating magnetic field formed by the output of the comparator that compares and outputs these voltages is synchronized over a relatively long time after starting. The rotation gradually increases in a non-linear manner that pulls into rotation, and the stability and certainty of starting of a sensorless brushless motor that has a large moment of inertia and takes a long time to start can be obtained.

According to the sixth aspect of the present invention, in particular, the first voltage generating circuit has a circuit configuration in which the constant current source energizes the capacitor to control its terminal voltage, and the second voltage generating circuit includes a resistor in the capacitor. Since the circuit configuration controls the terminal voltage of the capacitor by connecting, the frequency of the rotating magnetic field formed by the output of the comparator that compares and outputs these voltages is relatively steep after starting As a result, the stability and certainty of the starting of the sensorless brushless motor, which does not take much time to start with a small moment of inertia, can be obtained.

According to the invention of claim 7, the first voltage generating circuit, the second voltage generating circuit and the comparing circuit are constituted by an oscillator, a digital counter for counting its waveform and a comparator. Therefore, it becomes easy to set the change of the frequency of the rotating magnetic field formed by the output of the comparator over time, and it becomes easy to apply the sensorless type brushless motor.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of a control circuit of a sensorless brushless motor showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an output waveform of a comparison circuit in the starting circuit according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a drive signal based on the output of the comparison circuit in the startup circuit of the embodiment of the present invention.

FIG. 4 is a circuit configuration diagram of a main part showing a specific example 1 of the starting circuit of the present invention.

FIG. 5 is an explanatory diagram showing an output voltage waveform of Specific Example 1.

FIG. 6 is an explanatory diagram showing a frequency change of a rotating magnetic field relating to activation in the control circuit according to the embodiment of the present invention.

FIG. 7 is a circuit configuration diagram of a main part showing a second specific example of the starting circuit of the present invention.

FIG. 8 is an explanatory diagram showing an output voltage waveform of Example 2.

FIG. 9 is a circuit configuration diagram of a main part showing a third specific example of the starting circuit of the present invention.

FIG. 10 is an explanatory diagram showing an output voltage waveform of Example 3.

FIG. 11 is a circuit configuration diagram of a main part showing a fourth specific example of the starting circuit of the present invention.

FIG. 12 is an explanatory diagram showing an output voltage waveform of Specific Example 4.

FIG. 13 is a circuit configuration diagram of an essential part showing a fifth specific example of the starting circuit of the present invention.

FIG. 14 is an explanatory diagram showing an output voltage waveform of Example 5.

FIG. 15 is a circuit configuration diagram of essential parts showing a sixth specific example of the starting circuit of the present invention.

[Explanation of symbols]

 1 Drive Circuit 2 Starter Circuit 3 Stator Coil 4 Stator Coil 5 Semiconductor Drive Signal Output Circuit 6 Transistor 7 Transistor 8 Transistor 9 Transistor 11 Position Detection Circuit 17 First Voltage Generation Circuit 18 Second Voltage Generation Circuit 19 Comparison Circuit 20 Counter 21 Power Supply 22 PNP Transistor 23 PNP Transistor 24 PNP Transistor 25 PNP Transistor 26 NPN Transistor 27 NPN Transistor 31 Resistor 33 Capacitor 34 Capacitor 35 Resistor 36 Resistor 37 Comparator 39 NPN Transistor 40 NPN Transistor 41 NPN Transistor 42 Resistor 43 Resistor 48 Resistor 49 Transistor 49 Transistor 50 resistor 51 capacitor 52 PNP transistor 53 capacitor 54 resistor 55 resistor 56 NP Transistor 57 PNP transistor 58 PNP transistor 59 resistor 60 capacitor 61 PNP transistor 62 NPN transistor 63 NPN transistor 65 capacitor 66 resistor 67 resistor 68 resistor 69 N-ary down counter 70 oscillator 71 N-ary up counter 72 comparator

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] January 21, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 3

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

A brushless motor control device according to a third aspect of the present invention is the control device for the brushless motor according to the first aspect, wherein the first voltage generating circuit is connected to a capacitor with a resistor to control the terminal voltage of the capacitor. The second voltage generating circuit is connected to the capacitor by connecting a resistor to the capacitor.
The circuit configuration controls the terminal voltage of the sensor .

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction content]

[0041] In the circuit configuration described above, the first conductive combination according pressure generation circuit 17 and the second voltage generating circuit 18 of the embodiment 2, the output voltage waveform as shown in FIG. 14 terminal b of Example 3 , D, which are input to the comparison circuit 19, a rotating magnetic field for starting is formed by the same operation as in each of the specific examples, and the brushless motor is started.
The frequency of the rotating magnetic field according to the fifth specific example is increased in a relatively short time from the start as shown in C of FIG. Thus, the magnetless rotor of the brushless motor and, for example, the blades attached to the magnet rotor have a small weight and a small moment of inertia, so that the brushless motor can be started up smoothly and in a short time.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kamo Shigeki 2-3-3 Marunouchi, Chiyoda-ku, Tokyo Sanryo Electric Co., Ltd. (72) Yuichi Fukase 2-3-2 Marunouchi, Chiyoda-ku, Tokyo No. Sanryo Electric Co., Ltd. (72) Inventor Takahiro Hayakawa 3-40 Tegano Shimobane, Nakatsugawa City, Gifu Prefecture Mitsubishi Electric Engineering Co., Ltd. Nagoya Office Nakatsugawa Branch Office

Claims (7)

[Claims] 1. A relative position between a stator coil and a magnet rotor is detected from a counter electromotive voltage of a stator coil connected in multiple phases, and a plurality of semiconductor elements are controlled by a drive signal output circuit based on the detected relative position to the stator coil. The first voltage generating circuit that generates a voltage that functionally rises from zero and the voltage that functionally gradually decreases from the set voltage value to the drive circuit that drives the brushless motor by determining the energization timing of The generated second voltage generating circuit is compared with the voltages of the first voltage generating circuit and the second voltage generating circuit, and when the voltage of the first voltage generating circuit exceeds the voltage of the second voltage generating circuit. A comparison circuit that resets the first voltage generation circuit, and a reset circuit that counts the output of the comparison circuit and resets the first voltage generation circuit and the second voltage generation circuit when the output reaches a predetermined number of times. A starter circuit including a counter for outputting a set signal, and the semiconductor element is operated by the drive signal output circuit by the output of the comparison circuit of the starter circuit at the time of start-up. Control device. 2. The relative positions of the stator coil and the magnet rotor are detected from the counter electromotive voltages of the stator coils connected in multiple phases, and a plurality of semiconductor elements are controlled by a drive signal output circuit based on the detected relative positions to the stator coil. A first voltage generating circuit that changes the terminal voltage of the capacitor by energizing the capacitor with a constant current source and a constant voltage by resistance division in the drive circuit that drives the brushless motor by determining the energization timing of The second voltage generating circuit is compared with the voltages of the first voltage generating circuit and the second voltage generating circuit, and when the voltage of the first voltage generating circuit exceeds the voltage of the second voltage generating circuit, the first voltage generating circuit And a second comparison circuit that resets the voltage generation circuit, and counts the output of the comparison circuit, and when the output reaches a predetermined number, the first voltage generation circuit and the second voltage generation circuit.
A starting circuit including a counter for outputting a reset signal for resetting the voltage generating circuit of is provided, and at the time of starting, the semiconductor element is operated by the drive signal output circuit by the output of the comparison circuit of the starting circuit. Characteristic brushless motor controller. 3. The circuit according to claim 1, wherein the first voltage generating circuit has a circuit configuration for controlling a terminal voltage of the capacitor by connecting a resistor to the capacitor, and the second voltage generating circuit is a capacitor. A brushless motor control device having a circuit configuration for energizing and controlling the terminal voltage. 4. The circuit structure according to claim 1, wherein the first voltage generation circuit has a circuit configuration in which a capacitor is energized by a constant current source to control the terminal voltage thereof, and the second voltage generation circuit is a capacitor by a constant current source. A brushless motor control device having a circuit configuration for energizing and controlling the terminal voltage. 5. The circuit structure according to claim 1, wherein the first voltage generating circuit has a circuit configuration for controlling a terminal voltage of the capacitor by connecting a resistor to the capacitor, and the second voltage generating circuit has a constant current. A controller for a brushless motor, which has a circuit configuration for energizing a capacitor by a power source to control its terminal voltage. 6. The circuit structure according to claim 1, wherein the first voltage generating circuit has a circuit configuration for energizing a capacitor by a constant current source to control the terminal voltage thereof, and the second voltage generating circuit is connected to the capacitor with a resistor. A brushless motor control device having a circuit configuration for controlling the terminal voltage of the capacitor. 7. The first voltage generation circuit, the second voltage generation circuit and the comparison circuit according to claim 1, wherein the first voltage generation circuit, the second voltage generation circuit and the comparison circuit are constituted by an oscillator, a digital counter for counting the waveform thereof, and a comparator. Controller for brushless motor.