JP2012115126A - Controller of brushless dc motor and blower having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controller of brushless DC motor, capable of suppressing variations in a motor output due to variations in the magnetic flux of a brushless DC motor.SOLUTION: The controller of brushless DC motor includes: an inverter circuit 9; rotational speed detection means 10 that detects a rotational speed of a brushless DC motor; current detection means 11 that detects an electric current supplied to the brushless DC motor; output control means 12 that controls a rotational speed and an electric current detected so that the brushless DC motor achieves a desired output; and correction means 14 that detects an induced voltage and an electrical angle simultaneously with the detection of the rotational speed of the brushless DC motor, changes a control parameter of an electric current as a reference previously stored in the output control means 12 according to detection results of the induced voltage and the electrical angle, and that corrects variations in the magnetic flux of the brushless DC motor.

Description

  The present invention relates to a control device for a brushless DC motor or a blower using the same.

  2. Description of the Related Art Conventionally, a brushless DC motor control device is known that uses an inverter to control the shaft output to a desired value and to control the work of an air conditioning fan or the like. (For example, refer to Patent Document 1).

  Hereinafter, the ventilation apparatus in Patent Document 1 will be described with reference to FIG. In Patent Document 1, as shown in FIG. 14, a ventilator that includes a blower that is driven by a DC motor 101 and has a control function for controlling the air volume at a constant level is controlled by a control circuit 102 of the ventilator based on a control function. The DC motor 101 is driven to control the constant air volume. Regarding the control function, it is a function acquired in advance by any reference ventilation device that is the same as this ventilation device. The variation of the DC motor 101 of the blower of the ventilation device is taken into the control function as a correction value. As the correction value, the DC motor 101 of the reference ventilator detects an arbitrary low rotation speed that is stabilized by the rotation speed detection circuit 103, the command voltage value at that time is measured by the command voltage generation circuit 104, and this command voltage value And the command voltage value when the DC motor 101 of the ventilator is at the same stable low speed as the DC motor 101 of the reference ventilator is calculated and obtained. By taking the difference from the obtained command voltage value as a correction value and storing it in the storage element 105, correction processing is performed only when the power is turned on to prevent deterioration of the air flow control accuracy of the DC air flow constant control of the DC motor 101. To do.

JP 2008-82634 A (summary, FIG. 2)

  However, with this type of conventional ventilator, it is necessary to observe the command voltage value at a stable arbitrary low speed, and when replacing parts after installation, the installation environment such as duct length and outside wind is required. When there is a factor that influences the air volume due to a disturbance element, there is a problem that stable correction becomes difficult. In particular, in the low rotation speed range, the voltage duty applied to the motor is small, and there is a problem in stability. In addition, motor variation factors include magnetization variation, winding variation, etc. Among them, induced voltage variation is relatively large as a result of magnetization variation, but these variations are corrected as total variation. Since this is a method, it is difficult to think that the correction constant is linear, and there is a problem that it is difficult to select a practical correction coefficient.

  The present invention solves the above-mentioned problem, and even if there is a factor including an installation environment such as duct length and external wind and disturbance factors, an induced voltage at an arbitrary number of rotations in the rotation state of the motor is obtained. Measured and corrected motor variation according to the induced voltage variation, enabling stable correction, and specialized by proportionally proportional to the induced voltage or induced voltage that is proportionally larger as a factor of motor variation An object of the present invention is to provide a brushless DC motor control device capable of improving the control accuracy of motor shaft output constant control (in the case of a blower, constant air volume control) by performing correction.

  In order to achieve this object, a brushless DC motor control device includes a rectifier for full-wave rectification of an AC power source, an inverter circuit including an upper stage and a lower stage, and bridge-connected with a plurality of switching elements, Rotation speed detection means for detecting the rotation speed of the brushless DC motor, current detection means for detecting current supplied from the inverter circuit to the brushless DC motor, and rotation detected so that the brushless DC motor has a desired output An output control means for controlling the number and current, and an induced voltage and an electrical angle are detected simultaneously with the detection of the rotational speed of the brushless DC motor, and stored in advance in the output control means in accordance with the detection result of the induced voltage and the electrical angle. Change the control parameter of the reference current or the number of revolutions to change the amount of magnetic flux of the brushless DC motor. And characterized in that it comprises a positive correcting means, thereby is to achieve the intended purpose.

  According to the present invention, a brushless DC motor control device includes a rectifying means for full-wave rectification of an AC power supply, an inverter circuit composed of an upper stage and a lower stage, each bridge-connected by a plurality of switching elements, and the brushless DC motor. Rotation speed detection means for detecting rotation speed, current detection means for detecting current supplied from the inverter circuit to the brushless DC motor, and rotation speed and current detected so that the brushless DC motor has a desired output. The output control means for controlling and the induced voltage and the electrical angle are detected simultaneously with the rotation speed detection of the brushless DC motor, and the reference current stored in the output control means in advance according to the detection result of the induced voltage and the electrical angle Alternatively, a correction means for correcting a variation in the magnetic flux amount of the brushless DC motor by changing a control parameter of the rotational speed. In this configuration, the number of rotations of the motor in the rotating state, the variation in the amount of magnetic flux of each motor, and the induced voltage variation proportional to the magnetic flux density can be detected at the same time. Even if there are factors including factors such as installation environment and disturbance factors such as length and outside wind, the induced voltage at any number of rotations in the rotating state of the motor is measured, and the motor according to the variation in the induced voltage The motor shaft output constant control is achieved by performing a specific correction based on a proportionally proportional to the induced voltage or the induced voltage that is proportionally large as a cause of motor variation. An object of the present invention is to provide a brushless DC motor control device capable of improving the control accuracy of air flow (constant air volume control in the case of a blower). It is.

The block diagram of the air blower 3 of Embodiment 1 of this invention Configuration diagram of the control device 2 Diagram showing the control parameters Flow chart of the correction means 14 The block diagram of the control apparatus 2b of Embodiment 2 of this invention Flow chart for detecting the induced voltage The block diagram of the control apparatus 2c of Embodiment 3 of this invention Modulation flowchart of the inverter circuit 9 Configuration diagram of control device 2d according to Embodiment 4 of the present invention The figure which shows the characteristic of the same rotation speed and motor efficiency, fan efficiency and ratio The block diagram of the control apparatus 2e of Embodiment 5 of this invention The block diagram of the control apparatus 2f of Embodiment 6 of this invention Figure showing a correspondence table for the same temperature conversion Configuration diagram of conventional ventilator (blower)

  According to a first aspect of the present invention, there is provided a brushless DC motor control device comprising: a rectifying means for full-wave rectification of an AC power supply; an inverter circuit comprising an upper stage and a lower stage, each bridge-connected by a plurality of switching elements; and the brushless DC Rotation speed detection means for detecting the rotation speed of the motor, current detection means for detecting the current supplied from the inverter circuit to the brushless DC motor, and the rotation speed detected so that the brushless DC motor has a desired output An output control means for controlling the current; and a reference stored in advance in the output control means according to the detection result of the induced voltage and the electrical angle according to the detection result of the induced voltage and the electrical angle. The correction which corrects the variation in the magnetic flux amount of the brushless DC motor by changing the control parameter of the current or the rotational speed It is obtained so as to comprise a stage. As a result, the rotational speed of the motor in a rotating state, the variation in the amount of magnetic flux of each motor, and the induced voltage variation proportional to the magnetic flux density are detected at the same time. Even if there is a factor that includes the installation environment and disturbance factors such as outside wind, the induced voltage at any number of rotations while the motor is rotating is measured, and the motor varies according to the variation in the induced voltage. Therefore, stable correction is possible even when parts are replaced after installation, and specialized correction by a proportionally proportional to the induced voltage or a proportionally proportional to induced voltage is possible as a factor of motor variation. By doing so, it is possible to improve the control accuracy of the motor shaft output constant control (in the case of a blower, constant air volume control).

  In addition, the brushless DC motor control apparatus according to claim 2 is configured to correct the variation in the magnetic flux amount of the brushless DC motor by the correcting means only during the initial operation. Accordingly, it is not necessary to always perform correction, and it is possible to correct the variation in the amount of magnetic flux as the induced voltage variation correction of the brushless DC motor with a simple configuration, and it is possible to correct the main variation factor of the motor.

  According to a third aspect of the present invention, there is provided the brushless DC motor control apparatus, wherein the correction means is executed after the speed becomes higher than a predetermined rotational speed. As a result, even in a motor with a small induced voltage, the induced voltage is proportional to the rotation speed, so that it is possible to prevent the detection error from being reduced or the detection error from increasing.

  According to a fourth aspect of the present invention, there is provided a brushless DC motor control device that selectively detects one of the three phases of the absolute value of the induced voltage. This eliminates the need to detect the phase voltages of all three phases, and can be realized with a simpler circuit configuration, thereby producing an effect that a cheaper circuit configuration can be achieved.

  In the brushless DC motor control device according to claim 5, the modulation of the inverter circuit is performed by energizing the rectangular wave, and the induced voltage is detected from any one phase where both the upper and lower switching elements are turned off. It is set as the structure which carries out. Thereby, even when the induced voltage is detected, continuous energization is possible, so that the accuracy at the time of detection can be improved, and correction control with higher accuracy can be achieved. Play.

  Further, in the brushless DC motor control device according to the sixth aspect, the modulation of the inverter circuit is executed by sine wave energization, and the energization pattern is intentionally generated so that both the upper and lower switching elements are turned off. Thus, detection of the induced voltage is performed. As a result, the pause interval is forcibly generated, so that the induced voltage can be measured, and the torque ripple of the motor is reduced by energizing the sine wave, so that the noise can be further reduced or the vibration can be reduced. There is an effect.

  According to a seventh aspect of the present invention, there is provided the brushless DC motor control device, wherein the correction means calculates the average value of the rotational speed and the induced voltage from the result of simultaneous detection of the rotational speed and the induced voltage of the brushless DC motor at least twice. The calculation is performed, and the variation correction is executed in accordance with the calculation result of the average rotation speed and the average value of the induced voltage. As a result, it is possible to correct the measurement variation of the rotational speed due to the torque ripple or the induced voltage, or the variation of the detection value due to the external noise or the self noise, thereby enabling more stable correction.

  In the brushless DC motor control device according to the eighth aspect, the modulation of the inverter circuit is performed by energizing the rectangular wave only at the time of starting rotation and detecting the absolute value of the induced voltage, and is performed by energizing the sine wave in the other period. It is a configuration. As a result, even when the induced voltage is detected, continuous energization is possible, so that the accuracy at the time of detection can be improved, and correction control with higher accuracy is possible. By energizing the sine wave, the torque ripple of the motor is reduced, so that it is possible to achieve further noise reduction or vibration reduction.

  According to a ninth aspect of the present invention, there is provided the brushless DC motor control apparatus, wherein the detection of the induced voltage is performed at any electrical angle excluding the point where the induced voltage becomes zero. This eliminates the need to simultaneously detect the induced voltage for three phases, shortens the processing time, increases the control cycle of the microprocessor, reduces external noise, and provides various additional functions. There is an effect that improvement can be achieved.

  The blower according to claim 10 is equipped with a control device for the brushless DC motor, connected to a blower fan as a load, and controlled to a desired blown amount. As a result, the brushless DC motor having the above-described effects is mounted, so that it is possible to reduce the variation in capability due to the reduction in control variation of each device. Stable correction is possible, and motor shaft output constant control (constant air volume control) is controlled by performing specialized correction with a relatively large induced voltage or a constant proportional to the induced voltage as a factor of motor variation. There is an effect that the accuracy can be improved.

  The controller for a brushless DC motor according to claim 11 is characterized in that the output control means is an efficiency correction coefficient for current or rotational speed based on a ratio of fan efficiency of the blower fan and motor efficiency of the brushless DC motor at a desired rotational speed. Is calculated, and the correction correction result of the magnetic flux amount of the brushless DC motor is secondarily corrected. As a result, the fan efficiency, the motor efficiency, and the ratio of the fan efficiency and the motor efficiency, which differ depending on the rotational speed, are reflected in the control parameter, so that the approximate part in the air flow control can be reduced, and the air flow control There is an effect that the accuracy can be improved.

  The brushless DC motor control device or blower device according to claim 12 is characterized in that the output control means has a current or rotational speed based on a ratio of fan efficiency of the blower fan and motor efficiency of the brushless DC motor at a desired rotational speed. The efficiency correction coefficient is calculated, and the variation correction result of the magnetic flux amount of the brushless DC motor is secondarily corrected. As a result, the rotational speed of the motor in the rotating state, the variation in the amount of magnetic flux of each motor, and the induced voltage variation proportional to the magnetic flux density are detected simultaneously, and the main motor variation factor can be corrected, the duct length, Even if there is a factor that includes the installation environment and disturbance factors such as outside wind, the induced voltage at any number of rotations while the motor is rotating is measured, and the motor varies according to the variation in the induced voltage. Therefore, stable correction is possible even when parts are replaced after installation, and specialized correction by a proportionally proportional to the induced voltage or a proportionally proportional to induced voltage is possible as a factor of motor variation. This improves the control accuracy of motor shaft output constant control (in the case of a blower, constant air volume control), and the fan varies depending on the rotational speed. The ratio of motor efficiency, fan efficiency and motor efficiency is reflected in the control parameters, so that the approximate part in the air flow control can be reduced and the accuracy of the air flow control can be further improved. Play.

  Further, the blower using the brushless DC motor control device according to claim 13 detects the temperature of the blown air or a related state variable, determines the air density of the blown air, and corrects the blown amount. It is set as the structure provided with the 2nd correction means to perform. Thereby, it becomes possible to suppress the control error of the blown air amount due to the temperature change of the blown air that fluctuates sequentially, and there is an effect that the accuracy of the blown air amount control can be further improved.

(Embodiment 1)
The structure of the air blower 3 which mounts the control apparatus 2 of the brushless DC motor 1 in this invention is demonstrated referring FIG. As shown in FIG. 1, the blower 3 includes a control device 2, a blower fan 4, a main body casing 5, and a blowout port 6. Further, as shown in FIG. 2, the control device 2 detects the number of rotations of the rectifying means 8 for full-wave rectification of the AC power supply 7, the inverter circuit 9 including switching elements 9 a to 9 f, and the brushless DC motor 1. Rotational speed detection means 10, current detection means 11 for detecting current supplied from the inverter circuit 9 to the brushless DC motor 1, and output for controlling the rotational speed and current detected so that the brushless DC motor 1 has a desired output. The control means 12, the induced voltage detection means 13 for detecting the induced voltage and the electrical angle simultaneously with the rotation speed detection of the brushless DC motor 1, and the output control means 12 stored in advance according to the detection result of the induced voltage and the electrical angle. A correction means 14 is provided for correcting variations in the amount of magnetic flux of the brushless DC motor 1 by changing the control parameter of the reference current or the rotational speed, It is controlled to be a desired air volume by rotating the blower fan 4 as a load of Rashiresu DC motor 1.

  First, it will be described that control can be made to achieve a desired air flow rate by controlling the current and the rotational speed of the brushless DC motor 1. The output P of the brushless DC motor 1 can be calculated from [Equation 1] from the torque constant Kt, the current I, and the rotational speed N.

  Further, the fan 4 has a shaft power L proportional to the multiplication result of the fifth power of the blade diameter D and the third power of the rotational speed NF of the blower fan 4 based on a similar law in general fluids (Expression 2). The air volume Q is proportional to the multiplication result of the third power of the blade diameter and the rotational speed NF of the blower fan 4 (Equation 3). Therefore, from [Equation 2] and [Equation 3], the shaft power L of the blower fan 4 can be calculated as [Equation 4] using the constant k.

  Here, since the blower fan 4 and the brushless DC motor 1 are directly connected, the shaft power L of the blower fan 4, the output P of the brushless DC motor 1, the rotational speed NF of the blower fan 4, and the rotational speed of the brushless DC motor 1 are used. N are considered equal. Therefore, it is considered that the air flow rate can be calculated as [Equation 5] from the constant K1, the torque constant Kt of the brushless DC motor 1, the current I, and the rotational speed N. For each predetermined air volume Qa, Since the rotation speed Na corresponding to the current Ia exists only, it is shown that the air flow rate can be indirectly controlled by controlling the current and the rotation speed.

  As shown in FIG. 3, this theoretical calculation is performed for the output control means 12 using the current Ia and the rotation speed Na as control parameters for the target airflow rates Qa1, Qa2, Qa3 (for example, when three airflow notches are used). This is realized by storing and controlling so that the actual detection value approaches the control parameter.

  Next, based on the above-described theoretical calculation, when control is performed so that the amount of air blown by the blower fan 4 becomes a desired amount of airflow, the variation factor due to individual differences of the brushless DC motor 1 is caused by individual adjustment of the blower 3. It is necessary to suppress. Here, among the variation factors of the brushless DC motor 1, the factor having a high influence on the variation in the air flow rate is the variation of the magnetic flux φ, which occupies about 5 to 6%. Since the magnetic flux φ is proportional to the magnetic flux density B, and the magnetic flux density B is proportional to the torque constant Kt, a variation component of the torque constant Kt is detected, and the control parameter for the reference rotation speed stored in advance is changed. The error of the desired air flow rate and the actual air flow rate can be suppressed by correcting the magnetic flux variation factor of the brushless DC motor 1.

  Next, a flowchart for calculating the correction amount of the correction unit 14 will be described with reference to FIG. As shown in FIG. 4, the correction means 14 is configured to be executed only at the first driving. First, the inverter circuit 9 is switched by the output control means 12 to drive the brushless DC motor 1. The correction means 14 receives the rotational speed of the brushless DC motor 1 and determines whether or not the rotational speed is higher than a predetermined rotational speed. The induced voltage detects any one of the three phases. The inverter circuit 9 performs modulation by energizing the rectangular wave, and the timing at which both one-phase upper and lower switching elements (for example, 9a and 9b) for detecting the induced voltage are turned off among the switching elements 9a to 9f. To detect. In the detection, the number of revolutions of the brushless DC motor 1 and the induced voltage are simultaneously detected at least twice, and the induced voltage at the electrical angle excluding the point where the induced voltage becomes zero is adopted. The electrical angle is detected by dividing the count value at the time of detection by the internal count value per rotation. From the calculated result, an electrical angle excluding a point where the induced voltage becomes zero (for example, a point where the calculated result is 0.0, 0.25, 0.5.0.75) is detected, and the aforementioned induction is detected. Used for voltage detection. Further, the average value of the rotation speed and the induced voltage is calculated from the detected result. From the result of the calculated rotation speed and the average value of the induced voltage, the ratio of the standard induced voltage at the rotation speed is calculated. The calculated ratio is multiplied by each of the reference control parameters of the current stored in advance to add variation correction.

  As described above, according to the detection result of the induced voltage and the electrical angle of the brushless DC motor 1, the control parameter of the reference rotational speed stored in advance in the output control means 12 is changed, and the magnetic flux amount of the brushless DC motor 1 is changed. The correction means 14 which corrects the variation of the above-mentioned is provided, and the amount of blown air can be controlled by correcting the variation of the magnetic flux of the brushless DC motor 1 as an individual difference.

  In the first embodiment, the correction by the correction unit 14 is an example of correcting the rotation speed. However, the current of the brushless DC motor 1 may be corrected.

(Embodiment 2)
The configuration of the control device 2b for the brushless DC motor 1 according to the second embodiment of the present invention will be described with reference to FIG.

  In addition, what has the same function as Embodiment 1 attaches | subjects the same code | symbol, and abbreviate | omits detailed description.

  As shown in FIG. 5, modulation of the inverter circuit 9 is executed by sine wave energization, and an energization pattern is intentionally generated so that the switching elements 9a to 9f are both turned off, and the induced voltage is detected. Output control means 12b is provided.

  Next, FIG. 6 shows a flowchart of detection of the induced voltage of the output control means 12b. As shown in FIG. 6, the flowchart for detecting the induced voltage is configured to be executed only at the first operation. First, the inverter circuit 9 is switched by the output control means 12b, and the brushless DC motor 1 is driven. Next, the rotational speed of the brushless DC motor 1 is input, and it is determined whether or not the rotational speed is higher than a predetermined rotational speed. If the predetermined number of revolutions is not exceeded, the modulation of the inverter circuit 9 is changed so that the number of revolutions is further increased. When it exceeds the predetermined number of revolutions, the switching to the inverter circuit 9 is stopped and the induced voltage of the brushless DC motor 1 is detected. The induction voltage is detected at least twice or more simultaneously by detecting the rotation speed and the induction voltage of the brushless DC motor 1 and adopting the induction voltage at an electrical angle excluding the point where the induction voltage becomes zero. The electrical angle is detected by dividing the count value at the time of detection by the internal count value per rotation. From the calculated result, an electrical angle excluding a point where the induced voltage becomes zero (for example, a point where the calculated result is 0.0, 0.25, 0.5.0.75) is detected, and the aforementioned induction is detected. Used for voltage detection. Further, the average value of the rotation speed and the induced voltage is calculated from the detected result. The reason for calculating the average by detecting at least twice or more is to stop the excitation to the brushless DC motor 1, so that the rotational speed due to the inertial force, frictional force of the rotating body including the blower fan 4, drag force due to the blown air, etc. This is because the induced voltage is attenuated and the detection error due to noise is reduced. From the result of the calculated rotation speed and the average value of the induced voltage, the ratio of the standard induced voltage at the rotation speed is calculated. Variance correction is performed by multiplying each of the reference rotation speed control parameters stored in advance by the calculated ratio.

  As described above, the output control that executes modulation of the inverter circuit 9 by sinusoidal energization, intentionally generates an energization pattern so that both the switching elements 9a to 9f are turned off, and executes detection of the induced voltage. Means 12b is provided, and the amount of blown air can be controlled by correcting variations in magnetic flux of the brushless DC motor 1 as individual differences.

  In the second embodiment, an example in which the correction target is the rotation speed has been described. However, the current of the brushless DC motor 1 may be corrected.

(Embodiment 3)
The configuration of the control device 2c for the brushless DC motor 1 according to Embodiment 3 of the present invention will be described with reference to FIG.

  In addition, what has the same function as Embodiment 1 and 2 attaches | subjects the same code | symbol, and abbreviate | omits detailed description.

  As shown in FIG. 7, there is provided an output control means 12c that performs modulation of the inverter circuit 9 by rectangular wave energization only at the start of rotation and detection of an induced voltage, and executes by sine wave energization in other periods.

  Next, FIG. 8 shows a modulation flowchart of the inverter circuit 9 of the output control means 12c. As shown in FIG. 8, the modulation flowchart branches at the time of starting rotation, detecting the induced voltage, and other normal periods. During the normal period, the brushless DC motor 1 is rotationally controlled by a control parameter corrected by detecting the induced voltage, and is controlled by the blower fan 4 so as to have a desired blown amount. At the start of rotation, since the rate of change of the rotational speed of the brushless DC motor 1 is large, switching to sine wave energization is performed when a predetermined rotational speed is exceeded by rectangular wave energization. In addition, when the induced voltage is detected, it is configured to be executed only at the first operation, and the induced voltage of the brushless DC motor 1 is detected when driven by rectangular wave energization and exceeds a predetermined rotation speed. The induction voltage is detected at least twice or more simultaneously by detecting the rotation speed and the induction voltage of the brushless DC motor 1 and adopting the induction voltage at an electrical angle excluding the point where the induction voltage becomes zero. The electrical angle is detected by dividing the count value at the time of detection by the internal count value per rotation. From the calculated result, an electrical angle excluding a point where the induced voltage becomes zero (for example, a point where the calculated result is 0.0, 0.25, 0.5.0.75) is detected, and the aforementioned induction is detected. Used for voltage detection. Further, the average value of the rotation speed and the induced voltage is calculated from the detected result. The reason for calculating the average by detecting at least twice or more is to reduce detection errors due to noise. From the result of the calculated rotation speed and the average value of the induced voltage, the ratio of the standard induced voltage at the rotation speed is calculated. Variance correction is performed by multiplying each of the reference rotation speed control parameters stored in advance by the calculated ratio. Thereafter, the control parameter rewrite flag is set, and at the time of restart, it is determined whether the operation is a normal operation or an operation for correction by the induced voltage depending on whether or not the rewrite flag is set.

  As described above, the modulation of the inverter circuit 9 is performed by energizing the rectangular wave, detection of the induced voltage is performed at the energizing timing when both the switching elements 9a to 9f are turned off, and the sine wave is energized during normal operation. It is equipped with output control means 12c, and can control the air flow by correcting variations in the magnetic flux of the brushless DC motor 1 as individual differences. Since it is normally driven by sine wave energization, noise and vibration are reduced. Can be achieved.

(Embodiment 4)
The configuration of the control device 2d for the brushless DC motor 1 according to the fourth embodiment of the present invention will be described with reference to FIG.

  In addition, what has the same function as Embodiments 1-3 attaches | subjects the same code | symbol, and abbreviate | omits detailed description.

  As illustrated in FIG. 9, the control device 2 d includes a rectifying unit 8 that performs full-wave rectification of the AC power supply 7, an inverter circuit 9 including switching elements 9 a to 9 f, and a rotational speed that detects the rotational speed of the brushless DC motor 1. Detection means 10, current detection means 11 for detecting current supplied from the inverter circuit 9 to the brushless DC motor 1, and output control means for controlling the rotation speed and current detected so that the brushless DC motor 1 has a desired output. 12d is provided, and it controls so that it may become a desired ventilation volume by rotating the ventilation fan 4 as a load of the brushless DC motor 1. FIG.

  Next, a method for calculating the efficiency correction coefficient of the current or the rotational speed and secondarily correcting the variation correction result of the magnetic flux amount of the brushless DC motor 1 will be described below. The characteristic equation taking into account the efficiency ηM of the brushless DC motor 1 can be calculated by [Equation 6].

  As for the blower fan 4, the axial power L of the blower fan 4 according to [Equation 2] and [Equation 3] can be calculated as shown in Equation 7 when the fan efficiency is ηF. .

  Here, since the blower fan 4 and the brushless DC motor 1 are directly connected, the shaft power L of the blower fan 4, the output P of the brushless DC motor 1, the rotational speed NF of the blower fan 4, and the rotational speed of the brushless DC motor 1 are used. N are considered equal. Therefore, the air flow rate can be calculated as shown in Equation 8 from the constant k2, the torque constant Kt of the brushless DC motor 1, the current I, the rotational speed N, the motor efficiency ηM, and the fan efficiency ηF.

  Accordingly, since there is only one rotation speed Nb corresponding to each current Ib at the desired rotation speed Nb for the predetermined air volume Qb, by controlling the current and the rotation speed at the desired rotation speed, It shows that it is possible to control the air flow rate indirectly. However, as shown in FIG. 10, motor efficiency ηM1, ηM2, ηM3, fan efficiency ηF1, ηF2, ηF3 and desired motor efficiency / fan efficiency ratios ηMF1, ηMF2, and ηMF3 are constant at desired rotational speeds Nb1, Nb2, and Nb3. Therefore, it is stored in the output control means 12d as a control parameter corresponding to each characteristic. By controlling so that the actual detection value approaches the control parameter, control is performed so as to obtain a desired air volume.

  As described above, the motor efficiency ηM, the fan efficiency ηF at the desired rotational speed, and the current or rotational speed efficiency correction coefficient corresponding to the motor efficiency / fan efficiency ratio ηMF are calculated, and the variation in the magnetic flux amount of the brushless DC motor is calculated. The correction result is secondarily corrected, the brushless DC motor 1 is controlled, the approximate portion in the air flow control can be reduced, and the air flow can be controlled more accurately.

(Embodiment 5)
The configuration of the control device 2e for the brushless DC motor 1 according to the fifth embodiment of the present invention will be described with reference to FIG.

  In addition, what has the same function as Embodiments 1-4 attaches | subjects the same code | symbol, and abbreviate | omits detailed description.

  As shown in FIG. 11, the control device 2 e includes a rectifying unit 8 that performs full-wave rectification of the AC power supply 7, an inverter circuit 9 including switching elements 9 a to 9 f, and a rotational speed that detects the rotational speed of the brushless DC motor 1. Detection means 10, current detection means 11 for detecting current supplied from the inverter circuit 9 to the brushless DC motor 1, and output control means for controlling the rotation speed and current detected so that the brushless DC motor 1 has a desired output. 12e, the induced voltage detection means 13 for detecting the induced voltage and the electrical angle simultaneously with the detection of the rotational speed of the brushless DC motor 1, and the reference stored in advance in the output control means 12e according to the detection result of the induced voltage and the electrical angle. And a correction means 14 for correcting the variation of the magnetic flux amount of the brushless DC motor 1 by changing the control parameter of the current or the rotational speed. It is controlled to be a desired air volume by rotating the blower fan 4 as a load of the brushless DC motor 1. Further, the output control means 12e is configured to calculate an efficiency correction coefficient of current or rotation speed, and to secondarily correct the variation correction result of the magnetic flux amount of the brushless DC motor 1.

  As described above, the motor efficiency ηM, the fan efficiency ηF at the desired rotational speed, and the control parameters corresponding to the motor efficiency / fan efficiency ratio ηMF are stored in the output control means 12e in advance, and the brushless DC motor 1 is controlled. The approximate portion in the air flow control can be reduced, and the reference rotation speed control parameter stored in advance in the output control means 12e is changed according to the detection result of the induced voltage and the electrical angle of the brushless DC motor 1. And since the correction | amendment means 14 which correct | amends the dispersion | variation in the magnetic flux amount of the brushless DC motor 1 is provided and the dispersion | variation in the magnetic flux of the brushless DC motor 1 as an individual difference is correct | amended, it can control a ventilation volume more accurately.

(Embodiment 6)
A configuration of the control device 2f of the brushless DC motor 1 according to the sixth embodiment of the present invention will be described with reference to FIG.

  In addition, what has the same function as Embodiment 1-5 attaches | subjects the same code | symbol, and abbreviate | omits detailed description.

  As illustrated in FIG. 12, the control device 2 f includes a rectifying unit 8 that performs full-wave rectification of the AC power supply 7, an inverter circuit 9 including switching elements 9 a to 9 f, and a rotational speed that detects the rotational speed of the brushless DC motor 1. Detection means 10, current detection means 11 for detecting current supplied from the inverter circuit 9 to the brushless DC motor 1, and output control means for controlling the rotation speed and current detected so that the brushless DC motor 1 has a desired output. 12f, the induced voltage detection means 13 for detecting the induced voltage and the electrical angle simultaneously with the rotation speed detection of the brushless DC motor 1, and the reference stored in advance in the output control means 12f according to the detection result of the induced voltage and the electrical angle. Correction means 14 for correcting variations in the amount of magnetic flux of the brushless DC motor 1 by changing the control parameter of the current or the rotational speed, and the correction means 4 is provided with second correction means 15 that inputs and stores the correction amount from 4 and converts the change in the correction amount into a temperature change of the blown air and corrects the blown air amount as an air density component. By controlling the blower fan 4 as a load, the control is performed so as to obtain a desired blown amount.

  Here, the volume by the air density can be calculated by proportional calculation, and can be expressed by [Equation 9], where Q <b> 0 is the blowing amount at the reference temperature t <b> 0.

  On the other hand, the brushless DC motor 1 has magnetic flux variations, and the correction amount varies depending on each. Therefore, since it is necessary to separate only the change due to the environmental change from the change amount of the correction amount, the change amount, that is, only the environmental change component is divided by dividing the correction amount at that time by the initial correction amount. be able to. The separated environmental change components (for example, A1 to A8) are converted into state variables related to the temperature (T1 to T8) of the brushless DC motor 1, that is, the temperature of the blown air, in the correspondence table shown in FIG. By substituting this temperature into t1 of [Equation 9], the air flow rate Q1 is calculated, and an error in the air flow rate is calculated and corrected.

  As described above, it becomes possible to suppress and control the control error of the air flow rate due to the temperature change of the blown air that fluctuates sequentially from the second correction unit 15 through the output control unit 12f, and the accuracy of the air flow rate control can be further improved. it can.

  In addition, it is good also as a structure which provides the temperature detection means which detects the temperature of blowing air directly, determines the air density of blowing air, and correct | amends ventilation volume.

  A brushless DC motor control device according to the present invention includes a rectifying means for full-wave rectification of an AC power supply, an inverter circuit composed of an upper stage and a lower stage, each bridge-connected by a plurality of switching elements, and the rotational speed of the brushless DC motor. A rotation speed detection means for detecting the current, a current detection means for detecting a current supplied from the inverter circuit to the brushless DC motor, and a rotation speed and current detected so that the brushless DC motor has a desired output. At the same time as detecting the number of rotations of the output control means and the brushless DC motor, an induced voltage and an electrical angle are detected, and a reference current control stored in advance in the output control means is controlled according to the detection result of the induced voltage and the electrical angle. A configuration comprising correction means for changing a parameter and correcting variations in the magnetic flux amount of the brushless DC motor Thus, the rotational speed of the motor in rotation, the variation in the amount of magnetic flux of each motor, and the induced voltage variation that is proportional to the magnetic flux density are detected at the same time. Even if there is a factor that includes the installation environment and disturbance factors such as outside wind, the induced voltage at any number of rotations while the motor is rotating is measured, and the motor varies according to the variation in the induced voltage. Therefore, stable correction is possible even when parts are replaced after installation, and specialized correction by a proportionally proportional to the induced voltage or a proportionally proportional to induced voltage is possible as a factor of motor variation. By doing so, the control accuracy of the motor shaft output constant control (in the case of a blower, constant air volume control) can be improved, and the ventilation air volume of a ventilation fan or the like can be improved. Be useful can also be used in applications such as a constant.

DESCRIPTION OF SYMBOLS 1 Brushless DC motor 2, 2b, 2c, 2d, 2e, 2f Control apparatus 3 Blower apparatus 4 Blower fan 5 Main body casing 6 Outlet 7 AC power supply 8 Rectification means 9 Inverter circuit 9a-9f Switching element 10 Rotation speed detection means 11 Current Detection means 12 Output control means 12b Output control means 12c Output control means 12d Output control means 12e Output control means 12f Output control means 13 Induced voltage detection means 14 Correction means 15 Second correction means

Claims (13)

A brushless DC motor control device for rotationally driving a load, comprising a rectifying means for full-wave rectification of an AC power supply, an inverter circuit composed of an upper stage and a lower stage, each bridged by a plurality of switching elements, and the brushless DC motor A rotational speed detecting means for detecting the rotational speed of
Current detection means for detecting a current supplied from the inverter circuit to the brushless DC motor; output control means for controlling the rotation speed and current detected so that the brushless DC motor has a desired output; and the brushless DC motor. The induced voltage and the electrical angle are detected at the same time as the rotation speed detection, and in accordance with the detection result of the induced voltage and the electrical angle, the reference current or the rotation speed control parameter stored in advance in the output control means is changed, A control device for a brushless DC motor, comprising correction means for correcting variations in the magnetic flux amount of the brushless DC motor. 2. The brushless DC motor control apparatus according to claim 1, wherein correction of variation in the magnetic flux amount of the brushless DC motor by the correcting means is executed only during the first operation. 3. The brushless DC motor control apparatus according to claim 1, wherein the correcting means is executed after the speed becomes higher than a predetermined rotational speed. 4. The brushless DC motor control device according to claim 1, wherein the induced voltage selectively detects any one of the three phases. 5. The inverter circuit according to claim 1, wherein modulation of the inverter circuit is performed by energizing a rectangular wave, and an induced voltage is detected from any one phase in which both the upper and lower switching elements are turned off. Brushless DC motor control device. The inverter circuit is modulated by sinusoidal energization, and an energization pattern is intentionally generated so that both the upper and lower switching elements are turned off, and the induced voltage is detected. Item 5. The brushless DC motor control device according to any one of Items 1 to 4. The correction means calculates the rotation speed and the induced voltage from the result of simultaneous detection of the rotation speed and the induced voltage of the brushless DC motor at least twice or more, and according to the calculation result of the average rotation speed and the average value of the induced voltage. The variation correction is executed, and the brushless DC motor control device according to any one of claims 1 to 6. 8. The inverter circuit according to claim 1, wherein the modulation of the inverter circuit is performed by energizing the rectangular wave only at the time of starting the rotation and detecting the induced voltage, and is performed by energizing the sine wave during the other period. Control device for brushless DC motor. 9. The control device for a brushless DC motor according to claim 1, wherein the detection of the induced voltage is executed at any electrical angle excluding a point where the induced voltage becomes zero. A blower using the brushless DC motor control device according to any one of claims 1 to 9, wherein a blower fan is connected as a load and controlled to a desired blown amount. The output control means calculates an efficiency correction coefficient for the current or the rotational speed based on a ratio between the fan efficiency of the blower fan and the motor efficiency of the brushless DC motor at a desired rotational speed, and corrects variations in the amount of magnetic flux of the brushless DC motor. A control apparatus for a brushless DC motor, wherein the result is secondarily corrected. The output control means calculates an efficiency correction coefficient for the current or the rotational speed based on a ratio between the fan efficiency of the blower fan and the motor efficiency of the brushless DC motor at a desired rotational speed, and corrects variations in the amount of magnetic flux of the brushless DC motor. The air blower using the brushless DC motor control device according to any one of claims 1 to 10, wherein the result is secondarily corrected. 13. The apparatus according to claim 10, further comprising second correction means for detecting the temperature of the blown air or a related state variable, determining the air density of the blown air, and correcting the blown amount. A blower using the brushless DC motor control device described in 1.

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