JP2906926B2 - Control device for brushless motor - Google Patents

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 driving a brushless motor by detecting a relative position between a stator coil and a magnet rotor from a back electromotive voltage of the stator coil.

[0002]

2. Description of the Related Art As a conventional control circuit for a brushless motor, for example, there is one as disclosed in Japanese Patent Application Laid-Open No. Sho 62-281791. This is a three-phase full-wave drive system, in which a Hall element detects magnetic flux of a magnet rotor, a position detection circuit inputs a three-phase position detection signal to a logic processing circuit, and controls a switching element to control a brushless motor. Is driven.

Further, as disclosed in Japanese Patent Application Laid-Open No. H4-161092, a relative position between a stator coil and a magnet rotor is detected by an induced voltage of a stator coil without using a position sensor such as a Hall element. There is also a sensorless control circuit that controls the switching element based on the driving of the brushless motor.

[0004]

In the conventional brushless motor control circuit as described above, the former is difficult to reduce the size and cost by the Hall element and its associated wiring. It is shifting to a sensorless system. However, in the sensorless system, the startup is likely to be unstable, and for example, as described in
In Japanese Patent Application Laid-Open No. 161092, a capacitor is charged and discharged alternately to supply current and shake to start the apparatus. And the malfunction due to the noise at the time of turning on the switch is prevented by turning off electricity during that time,
Challenges remain in the stability and reliability of startup.

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

[0006]

According to a first aspect of the present invention, there is provided a brushless motor control device comprising: a first voltage generation circuit for generating a voltage sequentially increasing from zero; a constant voltage; or a second voltage generating circuit for generating a set voltage value <br/> or RaSusumu voltage decrease, the voltage comparing of the first voltage generating circuit and the second voltage generating circuit, the first voltage A comparison circuit for resetting the first voltage generation circuit when the voltage of the generation circuit exceeds the voltage of the second voltage generation circuit; and a first voltage generation circuit for counting the output of the comparison circuit and counting the output when the output reaches a predetermined number. And second voltage generating circuit
The starting circuit comprising a counter for outputting a reset signal for resetting the provided so as to operate the semiconductor element by the drive signal output circuit at the output of the comparator circuit of the starting circuit starts Nico.

According to a second aspect of the present invention, there is provided a brushless motor control device comprising: a first voltage generation circuit for supplying a current to a capacitor by a power supply to vary a terminal voltage of the capacitor in a sensorless brushless motor drive circuit; A second voltage generation circuit that generates a constant voltage by resistance division is compared with voltages of the first voltage generation circuit and the second voltage generation circuit, and a voltage of the first voltage generation circuit is compared with a voltage of the second voltage generation circuit. And a comparator for resetting the first voltage generating circuit when the voltage exceeds the threshold voltage. When the output of the comparing circuit reaches a predetermined number, a reset signal is sent to the first voltage generating circuit and the second voltage generating circuit. A starter circuit including a counter for outputting the starter circuit, and at the time of start up, the semiconductor element is operated by the drive signal output circuit by the output of the comparison circuit of the starter circuit.
I do .

According to a third aspect of the present invention, there is provided a brushless motor control apparatus according to the first aspect.
Definitive a first voltage generating circuit by connecting the resistor to the capacitor, co and circuitry for controlling the terminal voltage of the capacitor, the capacitor terminals and the second voltage generating circuit by connecting a resistor to the capacitor a circuit configuration for controlling the voltage.

According to a fourth aspect of the present invention, there is provided a brushless motor control apparatus according to the first aspect.
Definitive a first voltage generating circuit and a circuit configuration for controlling the terminal voltage energizes the capacitor by the power source energizes the second voltage generating circuit to the capacitor by the power supply and circuitry for controlling the terminal voltage.

According to a fifth aspect of the present invention, there is provided a brushless motor control apparatus according to the first aspect.
Definitive a first voltage generating circuit by connecting the resistor to the capacitor, and the circuit configuration for controlling the terminal voltage of the capacitor, to control the terminal voltage energizes the capacitor by the power supply and its second voltage generating circuit circuit configuration to.

According to a sixth aspect of the present invention, there is provided a brushless motor control apparatus as defined in the first aspect.
Definitive a first voltage generating circuit and a circuit configuration for controlling the terminal voltage energizes the capacitor by the power supply, circuit for controlling the terminal voltage of the capacitor by connecting the resistor and the second voltage generating circuit to the capacitor configuration to.

According to a seventh aspect of the present invention, there is provided a brushless motor control apparatus as defined in the first aspect.
A first voltage generating circuit of the definitive, the comparison circuit and the second voltage generating circuit is constituted by an oscillator and the digital counter and the comparator counts the waveforms.

[0013]

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

According to the second aspect of the present invention, in particular, a first voltage generating circuit that varies a terminal voltage of the capacitor by energizing the capacitor by a power supply , and generates a constant voltage by resistance division. The voltage of the second voltage generating circuit is compared by a comparator. 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 of the circuit gradually increases linearly from below, 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 present invention, in particular, 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 connected to the capacitor. Since the circuit is configured to energize and control the terminal voltage, the frequency of the rotating magnetic field formed by the output of the comparator that compares and outputs these voltages has a non-linear characteristic that leads to synchronous rotation over a relatively long time after starting. It gradually increases gradually.

According to a fourth aspect of the present invention, in particular, the first voltage generating circuit has a circuit configuration for energizing a capacitor by a power supply and controlling a terminal voltage of the capacitor, and the second voltage generating circuit uses a capacitor from the power supply. And the terminal voltage thereof is controlled, the frequency of the rotating magnetic field formed by the output of the comparator that compares and outputs these voltages is set to the non-synchronous state that is drawn into the synchronous rotation over a relatively long time after starting. It gradually increases linearly.

According to the fifth aspect of the present invention, 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 controlled by a power supply. Since the circuit configuration energizes the capacitor and controls its terminal voltage, the frequency of the rotating magnetic field formed by the output of the comparator that compares and outputs these voltages is drawn into the synchronous rotation over a relatively long time from startup. It gradually increases non-linearly.

In the invention according to claim 6, the first voltage generating circuit has a circuit configuration in which a capacitor is supplied by a power supply to control a terminal voltage of the capacitor, and the second voltage generating circuit connects a resistor to the capacitor. Since the circuit configuration 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 gradually and non-linearly gradually increases after the start of operation. Will do.

In the invention of claim 7, the first voltage generating circuit, the second voltage generating circuit and the comparing circuit are particularly constituted by an oscillator, a digital counter for counting its waveform and a comparator. Accordingly, it is easy to set the change of the frequency of the rotating magnetic field formed with the output of the comparator over time.

[0020]

FIG. 1 is a circuit diagram of a control circuit of a two-phase sensorless type brushless motor according to an embodiment of the present invention, which comprises a drive circuit 1 and a start circuit 2. In the drive circuit 1, reference numerals 3 and 4 denote 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 control output of conduction interruption to four switching transistors 6, 7, 8, and 9 constituting a phase arm by a flip-flop circuit and a logic circuit. Reference numeral 10 denotes a positive power supply connected to the emitters of the upper transistors 6, 7 of the transistors 6, 7, 8, 9 configured as H bridges, and lower transistors 8, 9
And an intermediate power supply connected to the common connection terminals of the stator coils 3 and 4.
Reference numeral 11 denotes a position detection circuit that detects the relative position of the magnet rotor from the back electromotive force between the stator coil 3 and the stator coil 4 and outputs the detected position to the semiconductor drive signal output circuit 5.

In the starting circuit 2, reference numeral 12 denotes an oscillator for outputting a constant output pulse, and reference numeral 13 denotes a counter which operates and counts the output pulses of the oscillator 12 by a start start signal 14. Reference numeral 15 denotes a frequency sweep start signal 1 after a predetermined time has elapsed after the counter 13 has counted a predetermined number of pulses.
6 (which is a signal indicating that the frequency of the rotating magnetic field is gradually increased). Reference numerals 17 and 18 denote a first voltage generation circuit and a second voltage generation circuit whose voltage changes from an initial state in response to a frequency sweep start signal 16 from a start signal output circuit 15. The first voltage generation circuit 17 generates a voltage that rises functionally from zero. The second voltage generating circuit 18 generates a constant voltage or a voltage that gradually decreases in function from a set voltage value. 19 is a first voltage generating circuit 1
7 compares the voltage of the second voltage generating circuit 18 with the voltage of the second voltage generating circuit 18 and outputs a square wave corresponding to the magnitude of the difference. The output has a waveform as shown in FIG. The driving signal is input to the driving 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 outputs a reset signal. This reset signal is input to the first voltage generation circuit 17 and the second voltage generation circuit 18 and resets them to an 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 by the output of the position detection circuit 11.

In the control circuit having the above configuration, the driving circuit 1
Is based on 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 through the stator coil 3 from the high potential side to the middle potential side, and the transistor 6 is turned off after energizing for 90 degrees in phase. Next, the transistor 7 is turned on by the base signal, and the stator coil 4 is turned on.
, A current flows from the high potential side to the middle potential side, and the transistor 7 is turned off after energizing 90 degrees in phase. Subsequently, the transistor 8 is turned on by the base signal, a current flows through the stator coil 3 from the middle potential side to the low potential side, and the transistor 8 is turned off after energizing for 90 degrees in phase. Further, the transistor 9 is turned on by the base signal, and a current flows through the stator coil 4 from the medium potential side to the low potential side.
Turns off. Thereafter, by repeating this series of operations, a rotating magnetic field is generated in a certain direction, and the brushless motor rotates.

The position detection circuit 11 detects the position of the magnet rotor based on the back electromotive force generated in the stator coils 3 and 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 based on the base signals of the transistors 6, 7, 8, and 9. At the start of the startup, since no counter electromotive voltage is generated in the stator coils 3 and 4, the position detection circuit 11 cannot detect an appropriate position of the magnet rotor. Therefore, in the start-up, the signal from the start-up circuit 2 instead of the position detection circuit 11 is sent to the semiconductor drive signal output circuit 5 to be processed into a drive signal as shown in FIG. Start.

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

<Specific Example 1 of Starting Circuit> The first voltage generating circuit 17, the second voltage generating circuit 18, and the comparing circuit 19 of the starting circuit have a circuit configuration as shown in FIG. In FIG. 4, reference numeral 21 denotes a power supply of the first voltage generation circuit 17;
3 is a PNP transistor of a current mirror configuration, 24,
25 is also a PNP transistor of a current mirror configuration. 26, 27 and 28 are NPN transistors, 29 and 3
0, 31, and 32 are resistors. 33 and 34 are capacitors; a and b are input terminals and output terminals of the first voltage generating circuit 17; 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
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 denotes a resistor connected in series to the power supply 21, and an output terminal d of the second voltage generation circuit 18 is connected to the voltage dividing point. The input terminal of the second voltage generation circuit 18 is not required because the comparison voltage is generated only by the resistance voltage division.

In the comparison circuit 19, reference numeral 37 denotes an open collector type comparator, and the first voltage generation circuit 17
And the output of the second voltage generating circuit 18 are input. Reference numeral 38 denotes 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 denote resistors. 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 from on and the constant current determined by the resistor 31 is changed 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
The current flows to the collector of the NP transistor 23, whereby the capacitor 33 is charged. The terminal voltage rises linearly. The NPN transistor 28 is connected to the capacitor 33
Is received at the base and converted to a current by the resistor 32. In the current mirror PNP transistor 24 and the PNP transistor 25 connected to the NPN transistor 28, the same current as the current flowing in the PNP transistor 24 flows to the collector of the PNP transistor 25. Thereby, the capacitor 34 is charged. This voltage increases 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 input to the other input terminal of the comparator 37 via the resistor 42. Is done. The comparator 37 is the first voltage generation circuit 1
At the same time as the output voltage of the output voltage 7 exceeds the output voltage of the second voltage generating circuit 18, the output is inverted and the open state is changed to the ground state. When the output of the comparator 37 goes to the ground state, the NPN transistor 39 turns off and the NPN transistors 40 and 41 turn on. When the NPN transistor 40 is turned on, one input of the comparator 37 falls 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 generation circuit 17
Of the capacitor 34 connected to the output terminal b. 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 becomes open. 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 input terminal of the comparator 37 rises again to the potential of the output terminal d and returns. When the NPN transistor 41 is turned off, the capacitor 34 is charged with the current that increases linearly again, and the voltage at the output terminal b of the first voltage generating circuit 17 increases. Thereafter, this operation is repeated.

Counter 20 receiving the output of comparator 37
Outputs a reset signal when the output pulse of the comparator 37 is counted a predetermined number of times, turns off the NPN transistors 26 and 27 of the first voltage generation circuit 17, and turns off the capacitor 3
The voltages of 3, 34 are kept at zero. Thus, a voltage waveform as shown in FIG. 5 is generated at the output terminals b and d. Further, the semiconductor drive signal output circuit 5 receiving the output of the comparator 37 operates while the reset signal from the counter 20 is not input.
The output from the comparator 37 is signal-processed to generate a transistor 6,
7, 8, 9 to form a rotating magnetic field for activation,
Start the brushless motor.

In the starting circuit 2 described above, as shown in FIG. 6A, the frequency of the rotating magnetic field that rises linearly with the passage of time is obtained.
The brushless motors with different loads can be started smoothly and reliably by simply changing the capacity of the motors 3 and 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 configuration is the same as that shown in FIG. That is, as shown in FIG. 7, the first voltage generation circuit 17 includes 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 generation circuit 18 includes a PNP transistor 52 and a capacitor 53 connected in series with the power supply 21 and a voltage dividing resistor 54,
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 a connection point between the resistor 50 and the capacitor 51. The input terminal c of the second voltage generation circuit 18 is P
Connected to the base of the NP transistor 52, the output terminal d
Is a common connection point between 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 generation circuit 17 and the input terminal c of the second voltage generation circuit 18, the NPN transistor 49 and the PNP transistor 52
Turns off from the on state. Since one is an NPN transistor 49 and the other is a PNP transistor 52, an interface is required to turn on / off with the same frequency sweep start signal 16. When the NPN transistor 49 of the first voltage generation circuit 17 is turned off, the capacitor 51 is charged through the resistor 50, and the voltage of the output terminal b is changed from the ground toward the power supply 21 by 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 generation circuit 18 is turned off, the voltage at the output terminal d is an exponential function based on the time constant determined by the capacitor 53 and the resistors 54 and 55 from the power supply 21 toward the voltage division of the resistors 54 and 55. Decline. These are input to the comparison circuit 19, and a rotating magnetic field for starting is formed by the same operation as in the first embodiment, and the brushless motor starts. Output terminals b and d of the specific example 2
As shown in FIG. 8, the frequency of the rotating magnetic field becomes a low frequency that leads to synchronous rotation for a relatively long time from the start, as shown in FIG. 6B. As a result, when the magnet rotor of the brushless motor and the blade attached thereto, for example, the weight is large and the moment of inertia is large and it takes a long time to start the motor, the motor can be reliably started without step-out.

<Embodiment 3 of Starting Circuit> In this embodiment, 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 specific example 2, and the description of the same components is given the same reference numeral in the drawings and the description is omitted. That is, as shown in FIG. 9, the first voltage generating circuit 17 includes an NPN transistor 56, PNP transistors 57 and 58 having 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 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 between 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 generation circuit 17 and the input terminal c of the second voltage generation circuit 18, the NPN transistor 56 and the PNP transistor 61
Turns off from the on state. N of the first voltage generation circuit 17
When the PN transistor 56 is turned off, the current determined by the resistor 59 flows through the PNP transistor 57, and the same current flows through the collector of the PNP transistor 58, so that the capacitor 60 is charged. The capacitor 60 is connected to the power supply 21, PN
For constant current source by P transistors 57 and 58 and resistor 59
Since the terminal voltage is charged with more constant current, the terminal voltage increases linearly from the ground toward the power supply 21.

When the PNP transistor 61 of the second voltage generation 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 to the collector of the second capacitor 65.
Is discharged from the power supply 21 toward a 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 at a constant current, the potential drops linearly. These are input to the comparison circuit 19, and a rotating magnetic field for starting is formed by the same operation as in the specific example 2, and the brushless motor starts. The voltage waveforms at the output terminals b and d of the specific example 3 are as shown in FIG. 10, and the frequency of the rotating magnetic field is a low frequency that pulls into the synchronous rotation for a relatively long time from the start as shown in FIG. 6B. As a result, when the magnet rotor of the brushless motor and the blade attached thereto, for example, the weight is large and the moment of inertia is large and it takes a long time to start the motor, the motor can be reliably started 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 that of the specific example 2 or the specific example 3, and the description of the same components is denoted by the same reference numeral in the drawings, and the description is omitted.
That is, as shown in the drawing, 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, as in the second embodiment. Further, the second voltage generating circuit 18 includes a PNP transistor 61 and a current mirror N
It comprises PN transistors 62, 63, a diode 64, a capacitor 65, and resistors 66, 67, 68.

In the above circuit configuration, the voltage waveform as shown in FIG. 12 is obtained from the combination of the first first voltage generation circuit 17 of the second embodiment and the second voltage generation circuit 18 of the third embodiment. b, d, which are
9, a rotating magnetic field for starting is formed by the same operation as in the above specific examples, and the brushless motor starts. The frequency of the rotating magnetic field according to the specific example 4 is B in FIG.
As described above, a low frequency is drawn into the synchronous rotation for a relatively long time from the start. As a result, when the magnet rotor of the brushless motor and the blade attached thereto, for example, the weight is large and the moment of inertia is large and it takes a long time to start the motor, the motor can be reliably started without step-out.

<Embodiment 5 of Starting Circuit> In this embodiment, 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 of the specific example 2 or the specific examples 3 and 4. The description of the same components will be denoted by the same reference numerals in the drawings, and description thereof will be omitted. That is, as shown in FIG.
Comprises 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 includes a PNP transistor 52 connected in series to the power supply 21, a capacitor 53, and voltage dividing resistors 54 and 55, similarly to the second embodiment.

[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, and a rotating magnetic field for starting is formed by the same operation as in each of the above specific examples, and the brushless motor starts.
The frequency of the rotating magnetic field according to the specific example 5 rises in a relatively short time from the start as shown in FIG. 6C. As a result, the brushless motor can be started smoothly without taking a long time to start, since the magnet rotor of the brushless motor and the weight of, for example, the blades attached to the magnet rotor are small and the moment of inertia is small.

<Embodiment 6 of Starting Circuit> In this embodiment, the first voltage generating circuit 17, the second voltage generating circuit 18, and the comparing 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 generation circuit 17 is composed of an N-ary down counter 69, and the second voltage generation circuit 18 is
And an N-ary up-counter 71 so that the respective outputs are input to a comparator 72. An arbitrary N value of the N-ary set signal is input to the N-ary down counter 69 in advance.

In the above circuit configuration, the start signal is N
When the N-ary up counter 71 and the N-ary up counter 71 are input to the comparator 72, the N-ary up counter 71 counts the clock of the oscillator 70 connected thereto. At this time, the output of the N-ary 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, and in synchronization with this, a reset signal is generated, and the N-ary up counter 71 is reset. Becomes zero. Further N
A countdown instruction signal is generated to the binary down counter 69, whereby the N binary down counter 69 counts down by 1 and the comparison input 1 becomes N value -1. At this time, since the comparison input 1 and the comparison input 2 are different, the comparator 72
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 started smoothly, and the
The change of the frequency of the rotating magnetic field formed with the passage of time over time can be easily set.

Although the embodiment has been described with reference to the two-phase full-wave driving system, the present invention can be similarly applied to a three-phase driving system.

[0045]

As is apparent from the above description of the embodiment, according to the first aspect of the present invention, a first voltage generating circuit,
The voltage of the second voltage generating circuit is compared by a 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. frequency of the rotating magnetic field formed by the output goes to transition gradually increases with time, starting output
Stops the output of the start-up circuit when
It shifts to drive by. Therefore, the stability and reliability of the start of the sensorless brushless motor can be obtained.

According to the second aspect of the present invention, in particular, the first voltage generating circuit for varying the terminal voltage of the capacitor by energizing the capacitor by the power supply , and the second voltage for generating a constant voltage by resistance division The voltage of the first voltage generating circuit is compared with the voltage of the first voltage generating circuit by the comparator.
When the voltage exceeds the voltage of the voltage generation circuit, the frequency of the rotating magnetic field formed by the output of the comparison circuit gradually increases from the bottom, and the magnitude of the load increases. Thereby, the gradient of the linear change of the frequency can be easily changed, and the responsiveness is improved.

According to the third aspect of the present invention, in particular, the first voltage generating circuit has a circuit configuration for controlling the terminal voltage of the capacitor by connecting the resistor to the capacitor, and the second voltage generating circuit includes the capacitor. And the terminal voltage thereof is controlled, the frequency of the rotating magnetic field formed by the output of the comparator that compares and outputs these voltages is set to the non-synchronous state that is drawn into the synchronous rotation over a relatively long time after starting. It becomes gradually and linearly and gradually increased, and the stability and reliability of the startup of the sensorless brushless motor that requires a large startup moment and a long startup time can be obtained.

According to the fourth aspect of the invention, in particular, the first voltage generating circuit has a circuit configuration for controlling the terminal voltage by supplying power to the capacitor by the power supply , and the second voltage generating circuit is controlled by the power supply . The voltage of the rotating magnetic field formed by the output of the comparator that compares and outputs these voltages changes to the synchronous rotation over a relatively long time from the start because of the circuit configuration that energizes the capacitor and controls its terminal voltage. It gradually increases in a non-linear manner so that the sensorless brushless motor having a large moment of inertia and requiring a long time to start provides stable and reliable starting.

According to the fifth aspect of the present invention, in particular, the first voltage generating circuit has a circuit configuration for controlling the terminal voltage of the capacitor by connecting the resistor to the capacitor, and the second voltage generating circuit includes the power supply. The voltage of the rotating magnetic field formed by the output of the comparator, which compares and outputs these voltages, is synchronized with the synchronous rotation over a relatively long time from the start, because the circuit configuration energizes the capacitor and controls its terminal voltage. It gradually increases in a non-linear manner so that the sensorless brushless motor having a large moment of inertia and requiring a long time to start provides stable and reliable starting.

According to the invention of claim 6, in particular, the first voltage generating circuit has a circuit configuration in which the power is supplied to the capacitor by the power supply to control the terminal voltage, and the second voltage generating circuit connects the resistor to the capacitor. Thus, since the circuit configuration 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 steeply nonlinear since the start of starting. As a result, the sensorless brushless motor can be started with a small moment of inertia in a short time.

In the invention according to claim 7, the first voltage generation circuit, the second voltage generation circuit and the comparison circuit are particularly constituted by an oscillator, a digital counter for counting its waveform and a comparator. Accordingly, it is easy to set the change of the frequency of the rotating magnetic field formed with the output of the comparator over time, and it is easy to apply the present invention to a sensorless brushless motor.

[Brief description of the drawings]

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

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

FIG. 3 is an explanatory diagram showing a drive signal based on an output of a comparison circuit in the starter circuit according to 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 a specific example 1.

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

FIG. 7 is a circuit diagram of a main part showing a specific example 2 of the starting circuit of the present invention.

FIG. 8 is an explanatory diagram illustrating an output voltage waveform of a specific example 2.

FIG. 9 is a circuit diagram of a main part showing a specific example 3 of the starting circuit of the present invention.

FIG. 10 is an explanatory diagram showing an output voltage waveform of a specific example 3.

FIG. 11 is a circuit diagram of a main part showing a specific example 4 of the starting circuit of the present invention.

FIG. 12 is an explanatory diagram showing an output voltage waveform of a specific example 4.

FIG. 13 is a circuit configuration diagram of main parts showing a specific example 5 of the starting circuit of the present invention.

FIG. 14 is an explanatory diagram showing an output voltage waveform of a specific example 5.

FIG. 15 is a circuit configuration diagram of main parts showing a specific example 6 of the start-up circuit of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 drive circuit 2 start 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 Resistance 36 Resistance 37 Comparator 39 NPN transistor 40 NPN transistor 41 NPN transistor 42 Resistance 43 Resistance 48 Resistance 49 NPN 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

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazushi Motoki 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation (72) Inventor Yuichi Fukase 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Inside Mitsubishi Electric Corporation (72) Inventor Takahiro Hayakawa 3-40 Tegano Shimowagi, Nakatsugawa City, Gifu Prefecture Mitsubishi Electric Engineering Co., Ltd. Nagoya Works Nakatsugawa Branch Office (56) References JP-A-6-90592 ( JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) H02P 6/18

Claims (7)

(57) [Claims] A relative position between a stator coil and a magnet rotor is detected from a back 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 relative position to control the stator coil. a drive circuit for driving the brushless motor by determining the conduction timing, the generated first voltage generating circuit for generating a voltage sequentially increases from zero, the constant voltage or the set voltage value or RaSusumu voltage decrease 2 voltage generators, and the voltages of the first voltage generator and the second voltage generator are compared. If the voltage of the first voltage generator exceeds the voltage of the second voltage generator, the first A comparison circuit for resetting the voltage generation circuit; and a reset signal for resetting the first voltage generation circuit and the second voltage generation circuit when the output of the comparison circuit is counted and the output reaches a predetermined number. A control device for a brushless motor, characterized in that a starter circuit including a counter for inputting data is provided, and at the time of start-up, the semiconductor element is operated by the drive signal output circuit by the output of the comparison circuit of the starter circuit. 2. A relative position between a stator coil and a magnet rotor is detected from a back electromotive voltage of a stator coil connected in a multi-phase connection, and a plurality of semiconductor elements are controlled by a drive signal output circuit based on the detected position to control the stator coil. A first voltage generating circuit that varies the terminal voltage of the capacitor by supplying power to a capacitor by a power supply, and a second voltage generating circuit that generates a constant voltage by resistance division. , The voltage of the first voltage generator and the voltage of the second voltage generator are compared, and if the voltage of the first voltage generator exceeds the voltage of the second voltage generator, the first voltage A comparison circuit for resetting the generation circuit, and counting the output of the comparison circuit and resetting the first voltage generation circuit and the second voltage generation circuit when the output reaches a predetermined number. A brushless motor provided with a starter circuit including a counter for outputting a reset signal to be activated, wherein the drive circuit outputs the drive circuit with the output of the comparison circuit of the starter circuit upon start-up. Control device. 3. The control of the brushless motor according to claim 1.
A first voltage generation circuit having a circuit configuration for controlling a terminal voltage of the capacitor by connecting a resistor to the capacitor; and a second voltage generation circuit having a resistor connected to the capacitor. A control circuit for controlling the terminal voltage of the capacitor. 4. The control of the brushless motor according to claim 1.
A control device, wherein the first voltage generating circuit has a circuit configuration for controlling the terminal voltage by supplying power to a capacitor by a power supply , and the second voltage generating circuit controls the terminal voltage by supplying power to a capacitor by a power supply. A brushless motor control device having a circuit configuration. 5. The control of the brushless motor according to claim 1.
A control device, 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 controlled by a power supply. A control device for a brushless motor, wherein the control device has a circuit configuration for controlling a terminal voltage by supplying a current to a capacitor. 6. The control of the brushless motor according to claim 1.
A first voltage generating circuit having a circuit configuration for controlling the terminal voltage by supplying power to a capacitor by a power supply , and connecting the second voltage generating circuit to a resistor by connecting a resistor to the capacitor. A brushless motor control device having a circuit configuration for controlling a terminal voltage. 7. The control of the brushless motor according to claim 1.
A control device for a brushless motor, 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 its waveform and a comparator. apparatus.