JP5773742B2 - Motor drive control device and motor drive control method - Google Patents

Description

  The present invention relates to a motor drive control device and a motor drive control method.

  For controlling the rotational speed of a direct current (DC) motor, pulse width modulation (PWM) control is frequently used.

Here, for example, a control device that performs PWM control using a PWM output function of a predetermined bit (for example, 8 bits) mounted on a microcomputer, and rotates a fan provided in an outdoor unit of an air conditioning facility 2. Description of the Related Art A control device that gives a speed command voltage to a fan motor and performs feedback control so as to keep the rotational speed of the fan motor at a target rotational speed has become widespread.
When the fluctuation range of the rotational speed of the fan motor at 1 count, which is the minimum resolution of 8-bit (0 to 254 count) PWM control, is 30 rpm, for example, as shown in FIG. 6, the fluctuation range of the rotational speed at 1 count. Is larger than the dead zone width of 10 rpm (± 5 rpm width of the target rotational speed), and therefore, the rotational speed of the fan motor cannot be controlled, and the rotational speed fluctuation, so-called hunting may occur.
For this reason, by improving the resolution of the PWM control, it is considered that the rotation speed of the fan motor can be controlled even in the dead zone, and the problem of hunting is solved.

  As a technique for improving the resolution of PWM control, in Patent Document 1, when the PWM drive frequency is constant, a peak value appears around the drive frequency f. Therefore, the drive frequency of the PWM drive signal is modulated. Describes a method of dispersing the influence of noise by dispersing noise peaks in a wide frequency band to improve the resolution.

JP 2007-43818 A

  However, since the technique described in Patent Document 1 improves the resolution by dispersing the influence of noise, it does not contribute to the improvement of resolution in a control that is not affected by noise or is small in the first place.

  The present invention has been made in view of such circumstances, and when controlling a fan motor by pulse width modulation of a predetermined bit, the fan motor can be controlled with a resolution exceeding the predetermined bit. An object is to provide a motor drive control device and a motor drive control method.

  In order to solve the above problems, the motor drive control device and motor drive control method of the present invention employ the following means.

That is, the motor drive control device according to the present invention is a motor drive control device that changes the rotation speed of the motor by pulse width modulation control of a predetermined bit, and includes a detection means that detects the rotation speed of the motor, and the detection means. Calculating means for calculating a control value for the motor based on a deviation between a detection value detected by the motor and a target value of the rotational speed of the motor by a constant multiple of the predetermined bit; and the control calculated by the calculating means A dividing unit that divides the value by the fixed multiple and calculates a quotient and a remainder; and a pulse having a duty value corresponding to the quotient calculated by the dividing unit is a first pulse, and a duty value corresponding to the remainder is calculated. A combination of the first pulse and the second pulse, wherein the pulse is a second pulse and the number of the first pulse and the second pulse is changed based on the remainder. The includes a pulse output means for outputting as a set, wherein the doubler is an integer of 2 or more, and in the pulse width modulation control the rotational speed of the fluctuation width of the motor is not performed in multiplied of the control value The value is smaller than the dead zone width .

  According to the present invention, the motor drive control device changes the rotation speed of the motor by pulse width modulation control of a predetermined bit (for example, 8 bits). Then, the motor drive control device obtains a control value of a predetermined bit for the motor based on a deviation between the detected value of the motor speed detected by the detecting means and the target value of the motor speed, that is, by feedback control. Yes. However, when the resolution is not sufficient with this predetermined bit, there is a possibility that the motor rotation speed fluctuates, so-called hunting.

Therefore, the control value is calculated by a fixed multiple of a predetermined bit by the calculation means.
Thereby, since the control value is a fixed multiple of the predetermined bit, the resolution of the control value is higher than the predetermined bit. However, since the motor drive control device changes the rotational speed of the motor by pulse width modulation of a predetermined bit, the output pulse must be a predetermined bit.

  For this reason, the quotient and the remainder are calculated by dividing the control value calculated by the calculating means by the fixed multiple value by the dividing means. By dividing the control value by a fixed value, the control value becomes a predetermined bit. Then, by the pulse output means, the pulse having the duty value corresponding to the quotient is set as the first pulse, the pulse having the duty value corresponding to the remainder is set as the second pulse, and the number of the first pulse and the second pulse is changed based on the remainder. The first pulse and the second pulse are output from the main controller 16 as a set. That is, the number of rotations of the motor is controlled by a combination of the first pulse and the second pulse, which is obtained from the result of dividing the control value by a constant value.

  Therefore, according to the present invention, when the motor is controlled by pulse width modulation of a predetermined bit, the motor can be controlled with a resolution exceeding the predetermined bit.

  In the motor drive control device of the present invention, the second pulse is a pulse having a duty value obtained by adding 1 to the quotient, and the pulse output means includes a total number of the first pulse and the second pulse. May be made to coincide with the fixed multiplication value, and the number of the second pulses may be made to coincide with the remainder, and the combination of the first pulse and the second pulse may be output as one set.

  According to the present invention, the pulse having a duty value obtained by adding 1 to the quotient calculated by the dividing means is used as the second pulse, the total number of the first pulse and the second pulse is made to coincide with the fixed multiple value, and Since the number of two pulses is matched with the remainder to make one set, the resolution can be further improved.

  Moreover, the motor drive control apparatus of this invention is good also considering the said motor as a motor which rotates the fan with which the outdoor unit of the air conditioner is equipped.

On the other hand, a motor drive control method according to the present invention is a motor drive control method for changing the rotation speed of a motor by pulse width modulation control of a predetermined bit, the first step of detecting the rotation speed of the motor, A second step of calculating a control value for the motor based on a deviation between a detected value detected in one step and a target value of the rotation speed of the motor by a constant multiple of the predetermined bit, and a calculation by the second step A third step of dividing the controlled value by the fixed value to calculate a quotient and a remainder; a pulse having a duty value corresponding to the quotient calculated in the third step is a first pulse; A combination of the first pulse and the second pulse in which a pulse having a duty value corresponding to the remainder is a second pulse and the number of the first pulse and the second pulse is changed based on the remainder. Viewed including a fourth step of outputting as a set, wherein the doubler is 2 or more integers, and dead band rotational speed of the fluctuation width of the motor in a pulse width modulation control is not performed in multiplied of the control value The value is smaller than the region width .

  According to the present invention, when the fan motor is controlled by pulse width modulation of a predetermined bit, there is an excellent effect that the fan motor can be controlled with a resolution exceeding the predetermined bit.

It is a block diagram of the motor drive control apparatus which concerns on embodiment of this invention. It is the schematic diagram which showed the PWM signal in the PWM control with respect to the fan motor which concerns on embodiment of this invention. It is a schematic diagram which shows an example of a dead zone area | region in the PWM control with respect to the fan motor which concerns on embodiment of this invention. It is the graph which showed the relationship between the speed command voltage which concerns on embodiment of this invention, and the rotation speed of a fan motor. It is the schematic diagram which showed the PWM signal in the PWM control with respect to the fan motor which concerns on another form. It is a schematic diagram which shows the dead zone area | region in the PWM control with respect to the conventional fan motor.

  Hereinafter, an embodiment of a motor drive control device and a motor drive control method according to the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram of a motor drive control device 10 according to the embodiment.
The motor drive control device 10 according to the present embodiment outputs a speed command voltage to a fan motor 14 that rotates a fan 12 provided in an outdoor unit of an air conditioning facility. The fan motor 14 rotates at a rotational speed corresponding to the input speed command voltage. Then, the motor drive control device 10 changes the speed command voltage by pulse width modulation (PWM) control of a predetermined bit (bit), and performs feedback control so that the rotational speed of the fan motor 14 is maintained at the target rotational speed.

  In the present embodiment, 8 bits are applied as an example of the predetermined bits, and the duty value of the PWM signal is changed between 0 and 254 counts (255 counts are not used, that is, the duty ratio is not 100%). .

  The motor drive control device 10 includes a main control unit 16, a speed command output unit 18, and a rotation speed detection unit 20.

  The main control unit 16 outputs an 8-bit PWM signal to the speed command output unit 18 via the PWM signal output port 22.

  When the input PWM signal is turned on (ON), the speed command output unit 18 emits light from the light emitting diode 24A of the photocoupler 24, and the light receiving element (phototransistor) 24B receives the emitted light. The speed command output unit 18 charges the capacitor 26 according to the number of times of light reception by the light receiving element 24B, and outputs the charged voltage to the fan motor 14 as a speed command voltage.

  The rotation speed detection unit 20 detects the rotation speed of the fan motor 14 using the photocoupler 28 and transmits the detected value to the main control unit 16.

  The configurations of the speed command output unit 18 and the rotation speed detection unit 20 are examples, and other configurations are possible as long as they have the same functions as the speed command output unit 18 and the rotation speed detection unit 20 according to the present embodiment. It doesn't matter.

  The main control unit 16 includes a control value calculation unit 30, a division unit 32, and a pulse output unit 34.

The control value calculation unit 30 is based on the deviation between the detection value from the rotation speed detection unit 20 input via the rotation speed detection port 36 and the target value of the rotation speed of the fan motor 14, that is, by feedback control. A control value for the motor 14 is calculated by a constant multiplication of 8 bits. In the present embodiment, 4 times is applied as an example of fixed magnification.
In this way, the control value is about 4 times 8 bits (0 count (1) +254 counts × 4 = 1017, 0 to 1016 counts), so that the resolution of the control value is higher than 8 bits. However, since the main controller 16 changes the rotational speed of the fan motor 14 by 8-bit pulse width modulation, the PWM signal must be 8 bits.

  Therefore, the division unit 32 divides the control value calculated by the control value calculation unit 30 by “4”, which is a fixed multiple, and calculates a quotient and a remainder. As described above, when the control value is divided by “4” which is a constant value, the control value is output as an 8-bit pulse when output from the PWM signal output port 22.

  Then, the pulse output unit 34 sets a pulse having a duty value corresponding to the quotient calculated by the division unit 32 as a first pulse, a pulse having a duty value corresponding to the remainder as a second pulse, the first pulse and the second pulse, Is changed based on the remainder, and the combination of the first pulse and the second pulse is output to the speed command output unit 18 as one set. That is, the rotational speed of the fan motor 14 is controlled by a combination of the first pulse and the second pulse, which is obtained from the result of dividing the control value by the fixed value.

  FIG. 2 is a schematic diagram showing a PWM signal in PWM control for the fan motor 14, and for comparison, also shows PWM control for the conventional fan motor 14, that is, a PWM signal in a form in which the control value is not fixed.

  As shown in FIG. 2, in the PWM control that does not perform constant multiplication of the control value, the control value calculated by the feedback control becomes the duty value (ON width) of the PWM signal as it is. Note that the PWM signal is output from the main control unit 16 every predetermined carrier cycle (1.012 kHz as an example in the present embodiment).

On the other hand, in the PWM control in which the control value is multiplied by 4 times 8 bits, the control value calculated by the feedback control is divided by “4” which is the constant multiplication, and the quotient and the remainder as the division result are PWM. It becomes the duty value (ON width) of the signal.
In the present embodiment, the first pulse is a pulse having the same duty value as the quotient that is the division result, and the second pulse is a pulse having a duty value that is obtained by adding 1 to the quotient that is the division result. Then, the pulse output unit 34 makes the total number of the first pulse and the second pulse coincide with the fixed multiple value, makes the number of the second pulse coincide with the remainder, and makes the first pulse and the second pulse A combination with two pulses is output as one set. That is, the number of first pulses is a value obtained by subtracting the remainder from the fixed multiple value.

  Specifically, with reference to FIG. 2, when the control value is 224, the division unit 32 outputs “56” as the quotient of the result of dividing the control value by “4”, and outputs “0” as the remainder. To do. The pulse output unit 34 outputs a PWM signal having a duty value of “56” as the first pulse, but does not output the second pulse, and the total number of the first pulse and the second pulse is a fixed multiple. In order to make them coincide with each other, four first pulses are output. That is, in this case, four first pulses having a duty value of “56” are set as one set and output from the main control unit 16.

  Note that the number of PWM signal outputs is counted by a PWM division counter that increments the count by one each time a PWM signal is output. The PWM division counter is changed according to a value whose count is a fixed multiple. In the present embodiment, since the constant multiplication value is “4”, the PWM division counter increments the count between “0” and “3”, and when the count reaches “3”, it becomes “0”. Return and repeat counting from “0” again.

  When the control value is 225, the division unit 32 outputs “56” as the quotient of the result of dividing the control value by “4”, and outputs “1” as the remainder. The pulse output unit 34 outputs a PWM signal having a duty value of “56” as the first pulse, and outputs a PWM signal having a duty value of “57” as the second pulse. The first pulse, the second pulse, In order to make the total number of the two coincide with the fixed value and to make the number of the second pulses coincide with the remainder, three first pulses are outputted and one second pulse is outputted. That is, in this case, one set of three first pulses with a duty value of “56” and one second pulse with a duty value of “57” is output from the main controller 16.

  When the control value is 226, the division unit 32 outputs “56” as a quotient obtained by dividing the control value by “4”, and outputs “2” as the remainder. The pulse output unit 34 outputs two PWM signals having a duty value “56” as the first pulse, and outputs two PWM signals having a duty value “57” as the second pulse. In other words, in this case, two first pulses with a duty value of “56” and two second pulses with a duty value of “57” are combined into one set and output from the main control unit 16.

  When the control value is 227, the division unit 32 outputs “56” as a quotient obtained by dividing the control value by “4”, and outputs “1” as the remainder. The pulse output unit 34 outputs three PWM signals having a duty value of “56” as the first pulse, and outputs one PWM signal having a duty value of “57” as the second pulse. That is, in this case, one set of one first pulse with a duty value “56” and three second pulses with a duty value “57” are output as one set.

  Further, when the control value is 228, the division unit 32 outputs “57” as the quotient of the result of dividing the control value by “4”, and outputs “0” as the remainder. The pulse output unit 34 outputs four PWM signals having a duty value “57” as the first pulse, but does not output the second pulse. That is, in this case, four first pulses having a duty value of “57” are set as one set and output from the main control unit 16.

  Note that the PWM signal that becomes the second pulse corresponds to the second pulse from the duty value corresponding to the first pulse from the duty value corresponding to the first pulse at the timing of the PWM output interrupt processing that occurs at each falling edge of the output of the PWM signal. Output by rewriting the duty value.

Table 1 is an example of an actual measurement value of resolution in the PWM control according to the present embodiment. As shown in Table 1, the motor drive control device 10 according to the present embodiment can vary the average value of the duty value (ON width) of the PWM signal by 0.25 counts, and accordingly, the control value It can be seen that the resolution of the speed command voltage and the rotational speed of the fan motor 14 is improved as compared with the PWM control that does not perform the constant multiplication.

FIG. 3 is a schematic diagram showing an example of a dead zone in PWM control for the fan motor 14 according to the present embodiment. In the conventional PWM control in which the control value is not fixed, the dead zone width is 10 rpm (the fluctuation range of the rotation speed of 1 count is 30 rpm, see FIG. 6).
As shown in FIG. 3, the motor drive control device 10 according to the present embodiment can perform the PWM control resolution for the fan motor 14 every 0.25 counts, which is four times the conventional control. The fluctuation range of the rotational speed with respect to the possible 0.25 count is 7.5 rpm, which is smaller than the conventional dead zone width of 10 rpm. As a result, it is possible to suppress the hunting of the fan motor 14.

Further, FIG. 4 is a graph showing the relationship between the speed command voltage and the rotation speed of the fan motor 14 according to the embodiment.
As shown in FIG. 4, the smaller the speed command voltage, the larger the change in the rotational speed of the fan motor 14 with respect to the change in the speed command voltage. This indicates that the smaller the speed command voltage, that is, the smaller the duty value (count number) of the PWM signal, the more fine control is required for the fan motor 14. Since the motor drive control device 10 according to the present embodiment has improved the resolution of the PWM control, the control of the fan motor 14 having the relationship as shown in FIG. It can be carried out.

As described above, the motor drive control device 10 according to the present embodiment detects the rotational speed of the fan motor 14 by the rotational speed detection unit 20, and the detected value and the rotational speed of the fan motor 14 by the control value calculation unit 30. A control value for the fan motor 14 based on the deviation from the target value is calculated by a constant multiplication of 8 bits. Then, the motor drive control device 10 calculates the quotient and the remainder by dividing the calculated control value by the fixed multiple value by the division unit 32, and the pulse output unit 34 calculates a pulse having a duty value corresponding to the quotient. Is a first pulse, a pulse having a duty value corresponding to the remainder is a second pulse, and the combination of the first pulse and the second pulse is changed based on the remainder of the number of the first pulse and the second pulse. Output as one set.
Therefore, the motor drive control device 10 according to the present embodiment controls the rotational speed of the fan motor 14 by a combination of the first pulse and the second pulse, which is obtained from the result of dividing the control value by a constant value. Therefore, the fan motor 14 can be controlled with a resolution exceeding 8 bits.

  Further, the motor drive control device 10 according to the present embodiment sets a pulse having a duty value obtained by adding 1 to the quotient calculated by the division unit 32 as the second pulse, and determines the total number of the first pulse and the second pulse. Since it is made to coincide with the double value, and the number of the second pulses is made to coincide with the remainder, and one set is made, the resolution can be further improved.

  As mentioned above, although this invention was demonstrated using the said embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. Various changes or improvements can be added to the above-described embodiment without departing from the gist of the invention, and embodiments to which the changes or improvements are added are also included in the technical scope of the present invention.

  For example, in the above-described embodiment, a mode in which 4 times is applied as the fixed value has been described. However, the present invention is not limited to this, and the fixed value is 2 times, 3 times, 5 times. It is good also as a form which applies the above.

  Moreover, although the motor drive control apparatus 10 demonstrated the form which changes the speed command voltage with respect to the fan motor 14 by 8-bit pulse width modulation in the said embodiment, this invention is not limited to this, The motor drive control device 10 may be configured to change the speed command voltage for the fan motor 14 by pulse width modulation with a bit number different from 8 bits. In the case of this form, for example, the number of bits is 4 bits, 16 bits, and 32 bits.

  In the above embodiment, the total number of the first pulse and the second pulse is matched with the fixed value, and the number of the second pulse is matched with the remaining number. It is not limited to this.

For example, when a remainder is generated as a result of division by the division unit 32, the number of second pulses may be an average value of the remainder. For example, as shown in FIG. 5A, when the fixed magnification is set to 4 times, the remainder of the result of dividing the control value by the fixed magnification is any one of “1”, “2”, and “3”. Since the average value of the remainder is “2” ((1 + 2 + 3) ÷ 3 = 2), when a remainder is generated as a result of division by the division unit 32, the number of second pulses is set to “2”.
Furthermore, in the case of this form, as shown in FIG. 5B, the total number of the first pulse and the second pulse may be half of the fixed value.

  Further, when a remainder is generated as a result of division by the division unit 32, the number of second pulses may be changed stepwise according to the remainder. In the case of this embodiment, if the fixed magnification is set to 5 times, the remainder of the result of dividing the control value by the fixed magnification is any one of “1”, “2”, “3”, and “4”. Therefore, when the remainder is “1” or “2”, the number of second pulses is “2”, and when the remainder is “3” or “4”, the number of second pulses is “4”. And

  Moreover, although the motor drive control apparatus 10 demonstrated the form which drives the fan motor 14 which rotates the fan 12 with which the motor drive control apparatus 10 was equipped with the outdoor unit of the air conditioning equipment in the said embodiment, this invention is limited to this. Instead, the motor drive control device 10 may drive the motor, and the object to be rotated by the motor may be different from the fan.

DESCRIPTION OF SYMBOLS 10 Motor drive control apparatus 12 Fan 14 Fan motor 16 Main control part 18 Speed command output part 20 Rotation speed detection part 30 Control value calculation part 32 Dividing part 34 Pulse output part

Claims (4)

A motor drive control device that changes the rotation speed of a motor by pulse width modulation control of a predetermined bit,
Detecting means for detecting the rotational speed of the motor;
A calculation means for calculating a control value for the motor based on a deviation between a detection value detected by the detection means and a target value of the rotation speed of the motor by a fixed multiple of the predetermined bit;
Dividing means for dividing the control value calculated by the calculating means by the fixed multiple value to calculate a quotient and a remainder;
A pulse having a duty value corresponding to the quotient calculated by the dividing means is a first pulse, a pulse having a duty value corresponding to the remainder is a second pulse, and the number of the first pulse and the second pulse is the number of the first pulse and the second pulse. Pulse output means for outputting a combination of the first pulse and the second pulse, which is changed based on the remainder, as one set;
Equipped with a,
The constant multiplication is an integer of 2 or more, and the motor drive control is such that the fluctuation range of the rotation speed of the motor is smaller than the dead zone width in the pulse width modulation control without performing the constant multiplication of the control value. apparatus. The second pulse is a pulse having a duty value obtained by adding 1 to the quotient.
The pulse output means makes the total number of the first pulse and the second pulse coincide with the fixed multiple value, and makes the number of the second pulse coincide with the remainder, The motor drive control device according to claim 1, wherein a combination of the first pulse and the second pulse is output as one set.   The motor drive control device according to claim 1, wherein the motor is a motor that rotates a fan provided in an outdoor unit of an air conditioner. A motor drive control method for changing the rotational speed of a motor by pulse width modulation control of a predetermined bit,
A first step of detecting the rotational speed of the motor;
A second step of calculating a control value for the motor based on a deviation between the detected value detected in the first step and a target value of the rotational speed of the motor by a constant multiple of the predetermined bit;
A third step of dividing the control value calculated in the second step by the constant value to calculate a quotient and a remainder;
A pulse having a duty value corresponding to the quotient calculated in the third step is a first pulse, a pulse having a duty value corresponding to the remainder is a second pulse, and the number of the first pulse and the second pulse is A fourth step of outputting a combination of the first pulse and the second pulse, which is changed based on the remainder, as one set;
Only including,
The constant multiplication is an integer of 2 or more, and the motor drive control is such that the fluctuation range of the rotation speed of the motor is smaller than the dead zone width in the pulse width modulation control without performing the constant multiplication of the control value. Method.

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