JP2002153084A - Control device for brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrences of restart phenomena so as to revolve a fan with stability and ensure the safety of operators. SOLUTION: A control device for brushless motor comprises: a duty ratio detection circuit 26 for detecting an instructed number of revolutions for rotating a rotor from a rotation instruction signal; a fan speed target value calculation circuit 27 for calculating a fan speed target value Dfan as a target for causing rotation based on the instructed number of revolutions; a fan speed change target value calculation circuit 28 for exercising such control that, when a fan speed target value Dfan is inputted when the rotor is in a stop, a fan speed change target value Dsfan for increasing the fan speed to the fan speed target value Dfan according to a first gradient is calculated and, when a fan speed target value Dfan for reducing the number of revolutions of the rotor is inputted when the rotor is in operation, a fan speed change target value Dsfan for reducing the fan speed to the fan speed target value Dfan according to a second gradient is calculated; and a lock protection control circuit 39 that outputs a stop signal indicating that the operation is stopped to a rotation driving means. When a stop signal is being outputted to the rotation driving means, calculation by the fan speed change target value calculation circuit 28 is canceled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a brushless motor which performs control in accordance with a rotation instruction signal indicating the number of rotations of a rotor. The present invention relates to a control device for a brushless motor.

[0002]

2. Description of the Related Art Conventionally, as a motor for rotating a blower fan in an air conditioner such as an automobile, a permanent magnet is used as a rotor, an armature winding is used as a stator, and a rectifying mechanism is replaced with a magnetic pole sensor and a switching element. Brushless motors are known. This brushless motor is supplied with drive power from a power supply circuit, and also has an IC (Integrat
The blower fan is controlled by a motor control circuit which is an ed circuit.

In such a motor control circuit, a duty signal, which is a pulse signal, is input, the duty signal is smoothed, the voltage level is detected, and the rotation speed of the blower fan is determined. In this motor control circuit, since the pulse signal is smoothed, even if the duty signal includes a short-time noise, the rotational speed of the blower fan that is rotating is not recognized as 0. . Therefore,
This motor control circuit has an advantage that restart does not occur during the rotation operation of the blower fan.

However, in the motor control circuit for performing such control, it is necessary to add an external smoothing circuit for smoothing the duty signal, and there is a problem that the cost of the device itself is high. Furthermore, in this motor control circuit,
It is necessary to add a plurality of external smoothing circuits according to the frequency of the duty signal. Furthermore, in this motor control circuit, there is a problem that a period for smoothing the duty signal by the external smoothing circuit is required, and the responsiveness of the blower fan is not good.

Therefore, conventionally, a motor control circuit for controlling the rotation speed of the blower fan without smoothing the duty signal has been used. In this motor control circuit, the pulse period of the duty signal is detected, the rotation speed target value of the blower fan is determined according to the period, and the rotation speed of the blower fan is controlled. According to this motor control circuit, there is an advantage that the responsiveness of the blower fan is fast because the target number of rotations is determined by directly detecting the duty signal.

In addition, the conventional motor control circuit includes a fan speed target value calculation circuit that determines a target rotation speed Dfan based on a duty signal and determines a target rotation speed. This fan speed target value calculation circuit includes an 8-bit counter, and as shown in FIG. 9, determines the rotational speed target value Dfan stepwise between 0 and 255 according to the cycle of the input duty signal. Was.

Furthermore, in the conventional motor control circuit, when the rotation of the blower fan is started, when the soft start target value Dsfan is increased toward the rotation speed target value Dfan as shown in FIG. Some include a soft start target value calculation circuit that performs a soft start control to gradually increase the soft start target value Dsfan by providing a gradient delay from the start. In this soft start target value calculation circuit,
The maximum rotation speed target value D for 1.5 seconds from the rotation start time
Control is performed to increase the soft start target value Dsfan at a gradient of 5% / sec with respect to the fan (100%), and to increase the soft start target value Dsfan at a gradient of 8% / sec after 1.5 seconds. In this soft start target value calculation circuit, when the soft start control is performed and the soft start target value Dsfan reaches the rotation speed target value Dfan, the delay is released.

On the other hand, in the conventional motor control circuit, when the rotation of the blower fan is stopped, as shown in FIG. 9 (b), the soft start target value Dsfan is controlled to be lowered without providing a gradient delay, and the blower fan is controlled. The rotation was stopped.

[0009]

However, in the prior art, the duty signal is directly detected and the rotation speed target value D is detected.
In the motor control device that determines the fan, if noise is mixed in the duty signal, the cycle of the duty signal includes noise, and the rotation fan target value Dfan of the blower fan may be recognized as “0”. Fan speed target value Dfa
When n is recognized as "0", the control to decrease the soft start target value Dsfan by the soft start target value calculation circuit is started as shown in FIG. 9B, and the fan speed target value Dfan is set at the next pulse. If detected, the soft start control is restarted toward the fan speed target value Dfan as shown in FIG. 9B. That is, in the conventional motor control device, the blower fan stops, and the soft start control by the soft start target value calculation circuit is started.
There is a problem that a restart phenomenon occurs.
In particular, in a control circuit for controlling a motor, there is a problem that the frequency of occurrence is high because the noise is severe.

On the other hand, the target rotation speed D
It is conceivable that when the fan is recognized as “0”, a gradient delay is provided to control the fan speed change target value Dsfan to gradually decrease to stop the rotation of the blower fan.

However, if a control for gradually lowering the fan speed change target value Dsfan is provided, another problem may occur. That is, lock protection control is performed so that the blower fan does not rotate despite the rotation instruction signal being input, and when the rotation instruction signal is turned off, the lock protection control is also released. At this time, since the circuit for calculating the fan speed change target value Dsfan often operates regardless of the lock protection control, if a slope delay is provided in the fan speed change target value Dsfan, the fan Will rotate. If the blower fan rotates when the rotation instruction signal is turned off in this manner, there is a possibility that the safety of the worker cannot be ensured.

In view of the above, the present invention has been proposed in view of the above-described circumstances, and in a device for controlling the number of revolutions of a blower fan, a restart phenomenon is prevented and the blower fan is rotated stably. It is an object of the present invention to provide a control device for a brushless motor, which can secure the safety of an operator.

[0013]

According to the present invention, there is provided a brushless motor having a permanent magnet as a rotor, an armature winding as a stator, and a rectifying mechanism as a magnetic pole sensor and a switching element. In a control device for a brushless motor for controlling the rotation speed, a rotation instruction signal for instructing the rotation speed of the rotor is input, and a rotation speed detecting means for detecting an instruction rotation speed for rotating the rotor from the rotation instruction signal. And first target value calculation means for calculating a rotation speed target value serving as a target for rotating the rotor based on the instructed rotation speed detected by the rotation speed detection means; and when the rotor is stopped. When the rotation speed target value calculated by the first target value calculation means is input, a soft star that calculates a rising target value to be increased toward the rotation speed target value according to a first gradient. When the rotor is rotating, the first target value calculating means calculates the first target value, and when the target value for decreasing the rotational speed of the rotor is inputted, the target rotational speed is set. A second target value calculating means for calculating a descending target value to be lowered toward the value in accordance with a second gradient; and a rotational speed target value calculated by the first target value calculating means or the second target value calculating means. A rotation drive unit that outputs a drive signal to a switching element that supplies power to the armature winding in accordance with the ascending target value or the descending target value calculated in and drives the rotor to rotate; Stop signal output means for outputting a stop signal indicating stop to the rotation drive means. The second target value calculation means stops the process of calculating the target rise value and the target decrease value while outputting a stop signal from the stop signal output means to the rotation drive means.

[0014]

According to the present invention, when the rotation speed target value which is calculated by the first target value calculation means and lowers the rotation speed of the rotor while the rotor is rotating is input, the first target value calculation means sets the first target value. A control for lowering the rotation speed target value in accordance with the two gradients can be performed, and when the stop signal is output from the stop signal output unit to the rotation driving unit, the process of calculating by the second target value calculation unit is released. Because it controls the fan speed,
The occurrence of the restart phenomenon can be prevented, and the blower fan can be stably rotated, and the safety of the worker can be ensured.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

The present invention is applied to, for example, a brushless motor configured as shown in FIG.

The brushless motor includes a motor control circuit 12 supplied with battery power from a battery terminal 11, a sensor magnet 13, and a sensor signal detection circuit 14.

The sensor magnet 13 is provided to indicate the rotational position of the rotor.
Two pairs of poles and south poles are arranged at an equal angle and attached to a shaft that rotates integrally with the rotor. Around this sensor magnet 13, three Hall ICs 13a for detecting the direction of the magnetic field generated from the sensor magnet 13
To 13c are evenly arranged on the inner periphery of the stator at intervals of 120 degrees.

The sensor signal detection circuit 14 outputs a detection signal based on a change in the direction of the magnetic field of the sensor magnet 13 to each hole I.
Inverted signals are generated using the detection signals input from C13a to 13c and supplied to the motor control circuit 12 as sensor signals together with the non-inverted signals as six signals.

The motor control circuit 12 calculates the rotation speed of the blower fan by referring to the sensor signal from the sensor signal detection circuit 14, and calculates the calculated rotation speed and the rotation speed indicated by the rotation instruction signal (PWM signal). To control the rotation speed of the blower fan.

The rotation instruction signal is a signal for specifying the rotation speed of the blower fan, and its duty ratio is controlled to specify the rotation speed. In other words, the rotation operation signal specifies the rotation speed of the blower fan by changing the ratio (duty ratio) of the H-level signal time to the L-level signal time. The rotation instruction signal has a duty ratio of 10%
By being changed within the normal instruction range of ９０90%, for example, the rotation speed of 0% to 100% of the rotation drive range of the blower fan is specified. The rotation instruction signal is a signal with a high duty ratio when the blowing fan is driven at a high rotation speed, and is a signal with a low duty ratio when the blowing fan is driven at a low rotation speed.

The motor control circuit 12 controls the MOSFETs Q1 to Q6 between on and off based on the sensor signal, and switches the direction of the current flowing through the armature coils 15a to 15f by the combination of the MOSFETs that are turned on.

Next, a detailed configuration of the motor control circuit 12 will be described with reference to FIG.

The motor control circuit 12 includes a first filter circuit 21 to which a voltage is input, a second filter circuit 22 to which a rotation instruction signal is input as an analog signal, and an ACC voltage calculation circuit 23.

The motor control circuit 12 is supplied with power from a power supply circuit (not shown), performs filter processing by a first filter circuit 21, and supplies it to an ACC voltage calculation circuit 23. The ACC voltage calculation circuit 23 divides the supplied power supply voltage and outputs the divided voltage value to the 8-bit data Dacc
To the voltage correction value calculation circuit 30.

When an analog rotation instruction signal is input from an air conditioning control circuit (not shown), the motor control circuit 12 performs a filtering process by the second filter circuit 22 and supplies the filtered signal to the ACC voltage calculation circuit 23. The calculation circuit 23 creates a digital rotation instruction signal and supplies it to the fan speed target value calculation circuit 27.

The motor control circuit 12 has a waveform conversion circuit 24 to which a sensor signal from the sensor signal detection circuit 14 is input.

The waveform conversion circuit 24 converts the waveform of the sensor signal from the sensor signal detection circuit 14 to obtain a sensor signal SA.
Generate H, SAL, SBH, SBL, SCH, and SCL to generate the sensor signal SA
H is supplied to the rotation speed detection circuit 35, and all the sensor signals are supplied to the Lo side output circuit 33 and the Hi side output circuit 34.

Further, the motor control circuit 12 includes a digital filter circuit 25 to which a rotation instruction signal is input as a digital signal, a duty ratio detection circuit 26, a fan speed target value calculation circuit 27, a fan speed change target value calculation circuit 28, A start switching circuit 29 is provided.

When a digital rotation instruction signal is input from an air conditioning control circuit (not shown), the motor control circuit 12 performs a filtering process by a digital filter circuit 25 and supplies the filtered signal to a duty ratio detection circuit 26.

The duty ratio detection circuit 26 detects the pulse period Tin by detecting the rise or fall of the rotation instruction signal as shown in FIG. The duty ratio detection circuit 26 detects the time Tinon from the fall of the previous pulse to the rise of the next pulse, that is, the ON voltage level section, and determines the pulse cycle Tin and the detected time Tinon
The duty ratio Dduty, which is the ratio (Tin / Tinon) with respect to the above, is detected. Here, the duty ratio Dduty is a value indicating the number of rotations of the blower motor, and is represented by 8-bit data. The duty ratio detection circuit 26 supplies the detected duty ratio Dduty to the fan speed target value calculation circuit 27.

The fan speed target value calculation circuit 27 has a table for converting the duty ratio Dduty into the rotation speed of the blower fan, and calculates a fan speed target value Dfan indicating the converted rotation speed of the blower fan. The fan speed target value calculation circuit 27 converts the fan speed target value Dfan into 8 bits (0 to 25).
The data is represented by the data of 5) and supplied to the fan speed change target value calculation circuit 28 and the sudden start switching circuit 29.

The fan speed change target value calculation circuit 28 has a table showing the relationship between the fan speed change target value Dsfan and the time until the blower fan reaches the stop fan speed target value Dfan. This fan speed change target value calculation circuit 2
8 calculates the fan speed change target value Dsfan with respect to time with reference to the table, and supplies the fan speed change target value Dsfan to the sudden start switching circuit 29. When the fan speed change target value calculation circuit 28 rises from off (0%), it performs a soft start control by setting a gradient delay so as to increase the fan speed to the fan speed target value Dfan.

The fan speed change target value calculation circuit 2
8 includes a table showing a relationship between the fan speed change target value Dsfan and the time when the fan speed is decreased from the target rotational speed Dfan when the blower fan is rotating at the target rotational speed Dfan. I have. The fan speed change target value calculating circuit 28 sets the slope delay by supplying the fan speed change target value Dsfan with respect to time to the sudden start switching circuit 29 with reference to the table.

The abrupt start switching circuit 29 comprises a selector, and sets a fan speed target value Dfan and a fan speed change target value Ds.
While the fan is input, a Hi signal or a Lo signal is input from an external sudden start input port. When the Hi signal is input from the sudden start input port, the sudden start switching circuit 29
Is output to the voltage correction value calculation circuit 30 as the target value Dfan 'as it is. The sudden start switching circuit 29 outputs the fan speed change target value Dsfan from the fan speed change target value calculation circuit 28 to the voltage correction value calculation circuit 30 as the target value Dfan 'when the Lo signal is input from the sudden start input port. . Furthermore, the motor control circuit 12 includes a voltage correction value calculation circuit 30, a reference data creation circuit 31, a PMW output circuit 32, a Lo side output circuit 3
3 and a Hi-side output circuit 34.

The reference data creation circuit 31 generates reference data Dref that expresses the magnitude of the center voltage of the power supply voltage of the brushless motor itself as 8-bit data, and supplies the reference data Dref to the voltage correction value calculation circuit 30.

The voltage correction value calculation circuit 30 includes the reference data Dref from the reference data creation circuit 31 and the voltage input data Da.
The ratio with respect to cc is detected, and the target value Dfan 'is corrected based on the detected ratio to generate a correction value Dfan''represented by 8-bit data. That is, the voltage correction value calculation circuit 30 calculates the correction value Dfan '' by performing an operation represented by (Dref / Dacc) ・ Dfan '= Dfan''.

The PWM output circuit 32 outputs the duty ratio of the correction value Dfan ″ to the Lo side output circuit 33 and an external PMW monitor (not shown) in an 8-bit cycle.

Further, the motor control circuit 12 includes a rotation number detection circuit 35, an overlap calculation circuit 36, an advance angle calculation circuit 37, a lock determination circuit 38, a lock protection control circuit 39, an output determination circuit 40, and an output ON / OFF circuit. An off-timer circuit 41 is provided.

Since the number of poles of the sensor magnet 13 is two poles and two periods correspond to one period of the rotor, the rotation number detection circuit 35 counts every two periods to determine the rotation period Tr of the rotor rotation number. To detect. The rotation number detection circuit 35 supplies the detected rotation period Tr of the rotor to the overlap calculation circuit 36, the advance angle calculation circuit 37, the Lo side output circuit 33, and the Hi side output circuit 34.

The overlap calculating circuit 36 determines the amount of overlap To based on the rotation period Tr. The overlap calculation circuit 36 has a table in which the overlap amount To with respect to the rotation period Tr is associated, and determines the overlap amount To with reference to the table. The overlap calculation circuit 36 outputs the determined overlap amount To to the Lo side output circuit 33 and the Hi side output circuit 34.

The advance amount calculation circuit 37 determines an advance time Tf for performing the advance control based on the rotation period Tr. The lead angle calculation circuit 37 has a table in which the lead time Tf is associated with the rotation period Tr, and determines the lead time Tf with reference to the table. Lead angle calculation circuit 3
7 is the Lo side output circuit 33 which determines the determined advance time Tf.
And output to the Hi-side output circuit 34 and to an external advance amount switching input terminal.

The lock determination circuit 38 outputs a Hi signal as a lock determination signal to the lock protection control circuit 39 when the rotation cycle Tr is equal to or longer than a predetermined time, and outputs a Lo signal when the rotation cycle Tr is equal to or shorter than the predetermined time.

The output judgment circuit 40 receives the target value Dfan "from the voltage correction value calculation circuit 30. When the target value Dfan" is "0", the lock protection control circuit 39 uses the Lo signal as an output judgment signal. And outputs a Hi signal when the target value Dfan ″ is other than “0”.

The output on / off timer circuit 41 receives the fan speed target value Dfan from the fan speed target value calculation circuit 27, starts counting when the fan speed target value Dfan rises from "0", and starts counting for a predetermined time or more. Hi when passed
The signal is output to the lock protection control circuit 39 as an output on / off timer signal.

The lock protection control circuit 39 is composed of two OR logics 61 and 62 and an AND logic 63 as shown in FIG. OR logic 61 is output decision circuit 4
0 and the output signal of the AND logic 63 as inputs, and the OR logic 62
The AND logic 63 receives an output on / off timer signal from the output on / off timer circuit 41, an output signal of the OR logic 61, and an OR logic 62. Is the input signal. Thereby, the lock protection control circuit 39 outputs the signal O in accordance with the on / off state of each signal.
An operation is performed by the R logics 61 and 62 and the AND logic 63 to generate and output a lock protection control signal. In such a lock protection control circuit 39, when the lock protection is performed, the lock protection is stably held even if the output determination signal becomes low.

Here, the abnormality determination circuit is provided for detecting overcurrent and overtemperature of the brushless motor, and is connected to a shunt resistor, thermistor, etc. provided outside the motor control circuit 12. Then, the voltage and the temperature supplied to the brushless motor are monitored, and when an overcurrent or an overtemperature occurs, an abnormality determination signal is output to the lock protection control circuit 39.

The Lo-side output circuit 33 and the Hi-side output circuit 34 provide the MOSFETs Q1 to Q6 based on the sensor signal from the waveform conversion circuit 24, the overlap Lo, the rotation period Tr, and the lock protection control signal.
Is opened and closed.

Next, a fan speed change target value calculation circuit 28
Will be described with reference to FIG.

The fan speed change target value calculating circuit 28 includes a frequency divider 51, an up / down counter 52, and a comparator 5.
3, a latch circuit 54, and a selector 55. The fan speed change target value calculation circuit 28
NOR circuit 56, RS flip-flop 57, NAND
A circuit 58 is provided.

The frequency divider 51 receives an external clock signal, divides the frequency of the input signal, generates a clock signal S1 for operating the fan speed change target value calculating circuit 28, and generates an up / down counter 52. To supply.

Further, the frequency divider 51 uses an external clock signal to increase the fan speed change target value Dsfan toward the fan speed target value Dfan and to increase the fan speed target signal Dsfan from the rising clock signal S2 and the fan speed target value Dfan. A falling clock signal S3 for lowering the fan speed change target value Dsfan is generated and supplied to the selector 55.

The selector 55 supplies the frequency divider 51 with a selection signal S4 for selecting the rising clock signal S2 or the falling clock signal S3 according to the signal from the NAND circuit 58.

The frequency divider 51 is reset when the selection signal S4 is input from the selector 55, and supplies the clock signal S1 to the up / down counter 52.

The up / down counter 52 includes a frequency divider 5
1 and the clock signal S1
Counts up or down in synchronization with. The up / down counter 52 supplies the count value A to the latch circuit 54, the comparator 53, and the NOR circuit 56.

The up / down counter 52 receives a lock protection control signal from the lock protection control circuit 39. When the Hi signal is input as the lock protection control signal, the up / down counter 52 resets the internally held count value to “0”. That is, when the up / down counter 52 is not being rotated by the lock protection control circuit 39, the counter value A is fixed to 0.

The up / down counter 52 performs an internal counter operation even when the count value is not set to "0", when the lock protection control circuit 39 performs lock protection control that does not rotate the blower fan. Do not count as off.

The comparator 53 receives the count value A from the up / down counter 52 and receives the fan speed target value Dfan from the fan speed target value calculation circuit 27.
Is entered. The comparator 53 calculates the count value A,
A comparison is made with the fan speed target value Dfan (B). The comparator 53 determines that the count value A is the fan speed target value Dfan
When the signal is smaller than (B) (A ≦ B), the Hi signal S that is counted up by the up / down counter 52 is set.
5 and the count value A becomes the fan speed target value Dfan
If it is larger than (B) (A ≧ B), the Lo signal S that counts down by the up / down counter 52
5 is generated. The comparator 53 outputs the Hi signal S5 or the Lo signal S5 to the up / down counter 52 and the NAN.
It is supplied to the D circuit 58.

The comparator 53 calculates the count value A
When the fan speed target value Dfan (B) is equal to the fan speed target value Dfan (B), a count stop signal S6 is output to the RS flip-flop 57 and the up / down counter 52. The up / down counter 52 stops counting in response to the count stop signal S6 from the comparator 53.

The RS flip-flop 57 receives the count stop signal S6 from the S input terminal and
A signal from the OR circuit 56 is input from an R input terminal. R
The S flip-flop 57 includes the up / down counter 5
When the count value A is output from No. 2, the Lo signal is input from the NOR circuit 56, and when the count value A is not output, the Hi signal is input from the NOR circuit 56. When the count stop signal S6 is input and the output of the count value A from the up / down counter 52 stops, the RS flip-flop 57 NANDs a signal indicating that the count value A has reached the fan speed target value Dfan.
Supply to circuit 58.

The NAND circuit 58 outputs a Hi signal to the selector 55 in response to the count value A reaching the fan speed target value Dfan.

The latch circuit 54 changes the count value A from the up / down counter 52 to a fan speed change target value Dsfan.
Output as

Next, a fan speed change target value calculation circuit 28
Will be described.

When the fan speed target value Dfan is input from the fan speed target value calculation circuit 27, the fan speed change target value calculation circuit 28 gradually changes the fan speed target value with the characteristic shown in FIG. 6 or FIG. Dsfan is set to a high or low value to be a fan speed target value Dfan. The fan speed change target value calculation circuit 28 generates the fan speed change target value Dsfan so as to sequentially change the target value Dfan ″ until the fan speed change target value Dsfan reaches the fan speed target value Dfan from 0%. I do.

According to FIG. 6A, the fan speed change target value calculating circuit 28 calculates 1.5% from the time when it started from 0%.
The fan speed change target value Dsfan is sequentially increased at 5% / sec only for seconds, and the fan speed change target value Dsfan is sequentially increased at 8% / sec after 1.5 seconds. Then, the fan speed change target value calculation circuit 28 ends the soft start control when the fan speed target value Dfan is reached. As a result, the fan speed change target value calculation circuit 28 calculates the fan speed change target value Ds from the start time to the fan speed target value Dfan.
The delay time t _D required to reach the fan speed target value Dfan in the ascending direction by raising the fan at a gradient.
Can be given.

On the other hand, according to FIG. 6B, when the fan speed change target value calculation circuit 28 is rotating at the fan speed target value Dfan, the fan speed target value calculation circuit 27 outputs “0”.
When the fan speed target value Dfan is input, the fan speed change target value Dsfan is lowered at 100% / sec from the fan speed target value Dfan. Accordingly, the fan speed change target value calculating circuit 28 causes the fan speed change target value Dsfan to be inclined and lowered until the fan speed change value reaches the fan speed target value Dfan. give the time _{t D.}

According to FIG. 7A, the fan speed change target value calculation circuit 28 calculates 8% /
The fan speed change target value Dsfan is raised in seconds, and when the fan speed change target value Dsfan reaches the fan speed target value Dfan, the soft start control ends. Thus, the fan speed change target value calculation circuit 28, by increasing by gradient from the start to the time to reach the fan speed target value Dfan, can give a delay time in the rising direction t _D.

On the other hand, according to FIG. 7 (b), the fan speed change target value calculation circuit 28 performs the fan speed target value calculation circuit 2 when the blower fan is rotating at the fan speed target value Dfan.
When the fan speed target value Dfan of “0” is input from 7, the fan speed change target value Dsfan is lowered at 100% / sec from the fan speed target value Dfan. Thus, the fan speed change target value calculation circuit 28, by lowering by gradient fan speed change target value Dsfan to reach the fan speed target value Dfan, provides a delay time t _D in descending direction.

The fan speed change target value calculating circuit 28 may set the gradient in the descending direction to not only 100% / sec but also the gradient. That is, the fan speed change target value calculation circuit 28
Determines the gradient in the descending direction within a range where the rotation of the blower fan stops immediately after the stop when the brushless motor is stopped.

Such a fan speed change target value calculation circuit 2
Reference numeral 8 denotes an up / down counter 5 when a lock protection control signal is input from the lock protection control circuit 39.
Since the operation of resetting the count value held in 2 or the operation of the counter is not performed, there is no possibility that the latch circuit 54 outputs the fan speed change target value Dsfan.

Therefore, according to the brushless motor,
When the rotation instruction signal is turned off, the fan speed change target value calculation circuit 28 operates to prevent the blower fan from rotating by mistake.

That is, if the above control is not performed, FIG.
As shown in the comparative example of (A), when the rotation instruction signal indicates the fan speed target value Dfan and is turned off at time t (a), the lock protection control by the lock protection control circuit 39 is released, The control to gradually reduce the fan speed change target value Dsfan is performed by the fan speed change target value calculation circuit 28 (b), so that the blower fan rotates for a short time after time t (c).

On the other hand, according to the brushless motor to which the present invention is applied, even if the rotation instruction signal indicates the fan speed target value Dfan as shown in FIG. When the signal is not counted by the up / down counter 52 and turned off at the time t (a), the lock protection control by the lock protection control circuit 39 is released, and the blower fan rotates after the time t. (B) and (c).

Therefore, according to the brushless motor, the blower fan does not rotate by mistake and the safety of the worker can be ensured.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a brushless motor to which the present invention has been applied.

FIG. 2 is a block diagram illustrating a configuration of a motor control circuit provided in a brushless motor to which the present invention has been applied.

FIG. 3 is a diagram for explaining detection of a duty ratio by a duty ratio detection circuit provided in a brushless motor to which the present invention is applied.

FIG. 4 is a circuit diagram showing a configuration of a lock protection control circuit.

FIG. 5 is a block diagram showing a configuration of a fan speed change target value calculation circuit provided in a brushless motor to which the present invention is applied.

6A and 6B are diagrams for explaining the operation of a soft start target value calculation circuit provided in a brushless motor to which the present invention is applied, and FIG. 6A illustrates a relationship between time and a fan speed change target value Dsfan in soft start control. FIG.
(A) is a figure which shows the relationship between time and the fan speed change target value Dsfan in control in the descending direction.

7A and 7B are diagrams for explaining another operation of the soft start target value calculation circuit provided in the brushless motor to which the present invention is applied, and FIG. 7A illustrates a time and a fan speed change target value Dsfan in the soft start control. FIG. 8A is a diagram illustrating a relationship between time and a fan speed change target value Dsfan in control in a descending direction.

8A and 8B are diagrams for explaining the operation of the brushless motor to which the present invention is applied, in which FIG. 8A shows a comparative example, FIG. 8B shows the operation of the brushless motor to which the present invention is applied, and FIG.
Shows a change in the rotation instruction signal, (b) shows a change in the fan speed change target value, and (c) shows a rotation speed of the blower fan.

FIG. 9 is a diagram for explaining the operation of the conventional soft start target value calculation circuit, where (a) is a diagram showing a relationship between time and a fan speed change target value Dsfan in soft start control; 4) is a diagram showing the relationship between the time and the fan speed change target value Dsfan in the control in the descending direction.

[Explanation of symbols]

 12 Motor control circuit 15 Armature coil 25 Digital filter circuit 26 Duty ratio detection circuit 27 Fan speed target value calculation circuit 28 Fan speed change target value calculation circuit 29 Sudden start switching circuit 30 Voltage correction value calculation circuit 31 Reference data creation circuit 32 PMW Output circuit 33 Lo side output circuit 34 Hi side output circuit 39 Lock protection control circuit 51 Divider 52 Up / Down counter 53 Comparator 54 Latch circuit 55 Selector 56 NOR circuit 57 RS flip-flop 58 NAND circuit 61, 62 OR logic 63 AND logic

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Eiji Takahashi 5-24-15 Minamidai, Nakano-ku, Tokyo Inside Calso Nic Kansei Corporation (72) Inventor Kazunori Yamada 5-24-15 Minamidai, Nakano-ku, Tokyo Calso Inside of Nick Kansei Corporation (72) Inventor Shiro Nakamura 5-24-15 Minamidai, Nakano-ku, Tokyo Calso F-Term in Kansai Kansei Corporation 5H560 AA01 BB04 BB12 DA02 DA19 DB20 EB01 GG04 HB10 SS02 TT01 TT02 TT07 TT15 UA05 XA04

Claims (3)

[Claims] 1. A brushless motor control device for controlling a brushless motor using a permanent magnet as a rotor, an armature winding as a stator, and a rectifying mechanism as a magnetic pole sensor and a switching element. Input a rotation instruction signal
A rotational speed detecting means for detecting an instruction rotational speed when rotating the rotor from a rotational instruction signal; and a target rotational speed for rotating the rotor based on the instruction rotational speed detected by the rotational speed detecting device. A first target value calculating means for calculating a numerical target value; and a rotational speed target value calculated by the first target value calculating means when the rotor is stopped;
A soft start control is performed to calculate a rising target value to be increased toward a rotation speed target value according to a first gradient. When the rotor is rotating, the soft start control is calculated by the first target value calculating means. A second target value calculating means for calculating, according to a second gradient, a descending target value for decreasing the rotational speed target value when the rotational speed target value for decreasing the rotational speed of the rotor is input; A drive signal is output to a switching element that supplies power to the armature winding according to the target rotation speed calculated by the target value calculation means or the target increase or decrease target value calculated by the second target value calculation means. A rotation drive unit for rotating the rotor, and a stop signal output unit for outputting a stop signal to the rotation drive unit to stop the operation of the rotation drive unit. A control unit for controlling the brushless motor, wherein the value calculating means stops the process of calculating the target value for raising and the target value for lowering while outputting a stop signal from the stop signal output means to the rotary drive means. . 2. The apparatus according to claim 1, wherein the second target value calculating means includes a counter for determining the target value for raising and the target value for lowering, and resets the counter value in response to the input of the stop signal. The control device for a brushless motor according to claim 1. 3. The method according to claim 2, wherein the second target value calculating means includes a counter for determining the ascending target value and the descending target value, and stops the operation of the counter in response to the input of the stop signal. The control device for a brushless motor according to claim 1, wherein