JP2010268647A - Brushless dc motor drive device and ventilation blower mounting the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control an air volume more precisely at a substantially constant level, using a simple configuration by suppressing variations in the current detection of a brushless DC motor and a ventilation blower mounting the motor. <P>SOLUTION: A current detection means 6, subjected to functional trimming, converts a pulse of a fixed period, according to the effective value of a current flowing to the stator 1 through an inverter circuit 5 thus producing a pulse signal. An air volume control means 7 is equipped with an air volume operating means 8 and a power indicating means 9; and since the air volume operating means 8 calculates a difference from a target air volume based on a rotation signal from a drive means 4 and a pulse signal from the current detection means 6, the power indicating means 9 provides the drive means 4 with an indication signal for increasing/decreasing power supply to the stator 1, and the air volume can be controlled precisely at a substantially constant level by using a simple configuration. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a brushless DC motor driving device mounted on a ventilation blower such as a range hood or a ceiling-embedded ventilation fan, and a ventilation blower equipped with the brushless DC motor drive device.

  Conventionally, this type of air blower capable of constant air volume operation detects the current of a brushless DC motor flowing in an inverter circuit provided separately from the motor by a control circuit, etc., and uses the relationship between the current and the rotational speed of the motor. And what has implement | achieved the driving | running by fixed air volume is known (for example, refer patent document 1).

  Hereinafter, the operation of the blower capable of performing the constant air volume operation will be described with reference to FIG.

  As shown in FIG. 5, the AC voltage supplied from the AC power supply 101 is converted into DC by the AC / DC conversion circuit 102, smoothed by the smoothing capacitor 103, and applied to the inverter circuit 105.

  The inverter circuit 105 drives the brushless DC motor 104 by sequentially connecting six switching elements. The brushless DC motor 104 is equipped with a sensor 106 for detecting the rotor position, such as a Hall element, and the rotation speed detection unit 108 detects the rotation speed of the brushless DC motor 104 based on the output of the sensor 106 and an inverter. The timing of switching the energization of the switching element of the circuit 105 is determined. Reference numeral 107 denotes a shunt resistor that detects a current flowing through the inverter circuit 105. The current detection unit 109 detects a current from the voltage across the shunt resistor 107. When the inverter circuit 105 is PWM controlled, the current flowing through the shunt resistor 107 fluctuates within one carrier. Therefore, the inverter circuit 105 is averaged by a filter or the like, and the averaged current is corrected to be necessary for the air volume calculation. The phase current of the brushless DC motor 104 is converted. The air volume calculation unit 110 calculates the air volume of the blower equipped with the brushless DC motor 104 from the current detected by the current detection unit 109 and the rotation speed detected by the rotation speed detection unit 108, and the control circuit of the blower body. Comparing the calculated target airflow with the commanded airflow, calculate the number of revolutions that realizes the operation with the target airflow, and output the instruction of the operating voltage to the speed control unit 111 so that the number of revolutions is achieved. ing. The speed control unit 111 changes the duty of the switching element of the inverter circuit 105 according to an instruction to control the rotation speed of the brushless DC motor 104 to the target rotation speed so that the airflow of the blower can be operated at a constant target airflow. .

Japanese Patent No. 3738685

  In such a conventional configuration, since the current flowing through the shunt resistor connected to the negative potential side terminal of the lower arm transistor of the inverter circuit is averaged and detected by a filter, an accurate motor phase current cannot be detected. There is a problem that the control and configuration become complicated, such as adding correction.

  The present invention solves such a conventional problem, and a brushless DC motor driving device and a ventilation air blower capable of controlling the air volume substantially accurately with a simple configuration by suppressing variations in current detection. The main purpose is to provide

  It is another object of the present invention to provide a brushless DC motor driving device and a ventilation air blower that can control an inexpensive air volume substantially constant by integrating a part of a control circuit with a motor to simplify the device.

  In order to achieve the above object, a brushless DC motor of the present invention and a ventilation air blower equipped with the motor are provided with a stator wound with windings, a rotor including a magnet, and a relative position of the magnet with respect to the stator. A position detecting means for detecting a target position; an inverter circuit for supplying a DC voltage to the stator; and the inverter circuit is driven to rotate the rotor in accordance with the position of the magnet detected by the position detecting means. Driving means for outputting a rotation signal and current detection means for converting to a pulse signal corresponding to an effective value of the current flowing through the winding via the inverter circuit, the rotation signal output from the driving means, and the current A brushless DC motor driving device comprising an air volume calculating means for controlling the current flowing through the stator based on the relationship with the pulse signal output from the detecting means. A.

  Since the current can be accurately detected by this means, it is possible to provide a brushless DC motor capable of controlling the accurate air volume substantially constant and a ventilation blower equipped with the brushless DC motor.

  The current detecting means is a function trimmed based on an arbitrary effective current to be detected.

  By this means, it is possible to detect current with high accuracy by suppressing variation in current detection, so that a brushless DC motor driving device and a ventilation blower capable of controlling the air volume with high accuracy substantially constant can be obtained.

  The current detection means is a function trimmed based on an effective value current having a carrier frequency higher than the audible range and less than 100% duty.

  By this means, it is possible to detect current with high accuracy by suppressing variation in current detection, so that a brushless DC motor driving device and a ventilation blower capable of controlling the air volume with high accuracy substantially constant can be obtained.

  The current detecting means is a function trimmed oscillator circuit for the output pulse signal.

  By this means, it is possible to detect current with high accuracy by suppressing variation in current detection, so that a brushless DC motor driving device and a ventilation blower capable of controlling the air volume with high accuracy substantially constant can be obtained.

  Further, the pulse signal output from the current detection means is obtained by changing the frequency according to the effective value current.

  By this means, it is possible to detect current with high accuracy by suppressing variation in current detection, and to provide a brushless DC motor driving device capable of controlling the air volume with high accuracy with a simple and inexpensive configuration, and ventilation ventilation. A device is obtained.

  Further, the pulse signal output from the current detection means is obtained by changing the duty in accordance with the effective value current.

  By this means, it is possible to detect current with high accuracy by suppressing variation in current detection, and to provide a brushless DC motor driving device capable of controlling the air volume with high accuracy with a simple and inexpensive configuration, and ventilation ventilation. A device is obtained.

  Further, the frequency of the pulse signal of the current detection means is set to several hundred Hz.

  By this means, it is possible to detect current with high accuracy by suppressing variation in current detection, and to provide a brushless DC motor driving device capable of controlling the air volume with high accuracy with a simple and inexpensive configuration, and ventilation ventilation. A device is obtained.

  The current detection means includes an insulation circuit.

  By this means, it is possible to detect current with high accuracy by suppressing variations in current detection and suppressing the influence of noise, and it is possible to control the air flow with high accuracy with a simple and inexpensive configuration. A DC motor driving device and a ventilation fan can be obtained.

  Further, the brushless DC motor has at least a position detection unit, an inverter circuit, and a current detection unit configured integrally with a stator.

  By this means, the apparatus can be simplified, and a brushless DC motor capable of controlling the air volume substantially at a lower price and a ventilation blower equipped with the brushless DC motor can be obtained.

  Further, the brushless DC motor is integrated with the stator by a mold resin that also serves as an outer shell.

  By this means, the apparatus can be simplified and the heat dissipation can be improved, so that it is possible to obtain a brushless DC motor capable of controlling the air volume substantially at a lower price and a ventilation blower equipped with the brushless DC motor.

  The brushless DC motor is one in which at least a part of the current detection means is exposed.

  By this means, the apparatus can be simplified and the heat dissipation can be improved, so that it is possible to obtain a brushless DC motor capable of controlling the air volume substantially at a lower price and a ventilation blower equipped with the brushless DC motor.

  According to the present invention, it is possible to provide a brushless DC motor capable of suppressing variation in current detection and controlling the air volume with a substantially constant accuracy and a ventilation blower equipped with the brushless DC motor.

  Further, it is possible to provide a brushless DC motor capable of simplifying the apparatus, being inexpensive, and capable of controlling the air volume substantially constant, and a ventilation blower equipped with the brushless DC motor.

1 is a schematic configuration diagram of a brushless DC motor according to a first embodiment of the present invention. Schematic configuration diagram of current detection means of the brushless DC motor Structure external view of ventilation fan using the same brushless DC motor ((a) side view, (b) bottom view, (c) front view) The figure which shows the structure of the brushless DC motor of Embodiment 2 Schematic configuration diagram of a conventional brushless DC motor

  According to the present invention, a stator having windings wound thereon, a rotor having magnets, position detecting means for detecting a relative position of the magnet with respect to the stator, and energizing the stator with a DC voltage An inverter circuit that drives the inverter circuit to rotate the rotor and output a rotation signal according to the position of the magnet detected by the position detecting means, and the inverter circuit through the inverter circuit Based on the relationship between the current detection means for converting to a pulse signal corresponding to the effective value of the current flowing through the winding, and the rotation signal output from the drive means and the pulse signal output from the current detection means, The brushless DC motor driving device is configured by an air volume calculating means for controlling the flowing current, and the air volume calculating means is configured to output a rotation signal output from the driving means and a pulse of the current detecting means. By controlling the current flowing through the difference between the air amount and the target air volume is calculated from the signal to the stator, and to control a substantially constant air volume of the fan attached to the rotor.

  Further, the current detection means is a brushless DC motor driving device characterized in that the function trimming is performed based on an arbitrary effective current detected, and the effective current detected by the current detection means by the function trimming is obtained. Adjustment is made so that it can be output in correspondence with a predetermined pulse signal.

  Further, the current detection means is a brushless DC motor driving device characterized in that the function trimming is performed based on an effective value current whose carrier frequency is higher than an audible range and less than 100% duty. Adjustment is made so that an effective value current having a detected carrier frequency equal to or higher than the audible range and less than 100% duty can be output in correspondence with a predetermined pulse signal.

  The current detecting means is a brushless DC motor driving device characterized in that the output pulse signal oscillation circuit is functionally trimmed, and the effective current detected by the current detecting means is determined in advance by functional trimming. The oscillation circuit is adjusted so that it can be output in accordance with the pulse signal.

  Further, the pulse signal output from the current detection means is a brushless DC motor driving device characterized in that the frequency changes according to the effective value current, and the effective value current detected by the current detection means by the function trimming. Is adjusted so as to correspond to a predetermined frequency of the pulse signal.

  Further, the pulse signal output from the current detection means is a brushless DC motor driving device characterized in that the duty changes in accordance with the effective value current, and the effective value current detected by the current detection means by the function trimming. Is adjusted so as to correspond to a predetermined duty of the pulse signal.

  Further, the frequency of the pulse signal of the current detection means is a brushless DC motor driving device characterized by being several hundred Hz, and the effective value current detected by the current detection means is determined in advance by function trimming. Adjustment is made so that it can be output in correspondence with a pulse signal of several hundred Hz.

  Further, the current detecting means is a brushless DC motor driving device characterized by comprising an insulating circuit, and an effective pulse current detected by the current detecting means by function trimming is used as a predetermined insulated pulse signal. It will be adjusted so that it can be output in accordance with.

  Further, the brushless DC motor is a brushless DC motor characterized in that at least a position detection means, an inverter circuit, and a current detection means are integrated with a stator, and a position detection which is a part of a control circuit. The apparatus can be simplified by integrating the means, the inverter circuit, and the current detection means with the stator and the motor.

  In addition, the brushless DC motor is a brushless DC motor characterized by being integrated with the stator with a mold resin that also serves as an outer shell. The heat generated from the stator and circuit components is efficiently transferred through the mold resin. It will dissipate heat well.

  The brushless DC motor is a brushless DC motor characterized in that at least a part of the current detection means is exposed, and the current detection means can be adjusted after the motor is completed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
Embodiment 1 of the present invention will be described with reference to FIGS.

  FIG. 1 is a schematic configuration diagram of a brushless DC motor driving device of the present invention, FIG. 2 is an example of a schematic configuration diagram of a current detection unit of the present invention, and FIG. 3 is a ventilation blower equipped with the brushless DC motor of the present invention. 3 (a) is a side view of the structural external view of the ventilation blower, FIG. 3 (b) is a bottom view of the structural external view of the ventilation blower, and FIG. 3 (c) is a ventilation view. It is a front view of the structure external view of an air blower.

  As shown in FIG. 1, reference numeral 1 denotes a stator having windings wound thereon, and 2 denotes a rotor having a magnet. The relative position of the rotor 2 with respect to the stator 1 is determined by a magnetic sensor such as a hall element or the like. The position detecting means 3 such as a Hall IC detects it. The driving means 4 drives the switching elements of the inverter circuit 5 such as transistors, IGBTs (Insulated Gate Bipolar Transistors), MOSFETs (Metal Oxide Field Transistor Transistors), etc. in a predetermined order according to the signal of the position detecting means 3. Then, electric power is supplied to the windings of the stator 1 to rotate the rotor 2. The driving means 4 outputs a rotation signal corresponding to the rotation speed of the rotor 2. The current detection means 6 converts it into a pulse signal corresponding to the effective value of the current flowing through the stator 1 via the inverter circuit 5. The air volume control means 7 is, for example, a microcomputer and includes an air volume calculation means 8 and a power instruction means 9, and calculates a difference between the target air volume from the rotation signal of the driving means 4 and the pulse signal of the current detection means 6. Power instruction means 9 for giving an instruction signal to the drive means 4 so as to increase or decrease the power supplied to the air volume calculation means 8 and the stator 1.

  Next, the configuration of the current detection means 6 will be described.

  As shown in FIG. 2, the current detection means 6 includes a filter circuit 10 that filters a voltage generated across the shunt resistor Rs, an oscillation circuit 11 that generates a pulse having a constant period, and an amplification that amplifies the output signal of the filter circuit 10. In the pulse converter 13 that converts the circuit 12 and the pulse signal according to the output of the amplifier circuit 12, the pulse conversion means is, for example, a PLD (Programmable Logic Device) or a microcomputer. For example, a trimming resistor 14 which is a resistor that can be used for functional trimming by a laser is connected to the amplifier circuit 12.

  As shown in FIG. 3, the ventilation blower equipped with the brushless DC motor driving device of the present invention has a structure in which the brushless DC motor 16 is attached to the casing 15 and the blower fan 17 is attached to the rotor 2 of the brushless DC motor 16. Yes, this ventilation blower is attached to the ceiling, and the centrifugal blower fan 17 is rotated to suck or exhaust indoor air to ventilate the room.

The operating air flow rate Q of the blower is expressed by a relational expression P∝Q · N ² between the motor output P and the operating air flow rate Q and the rotational speed N derived from the similarity law of general fluid, the motor output P, the induced voltage E ₀ of the motor, and the motor relation P = E ₀ · I of the current I, from the relation E ₀ = K _E · N of the rotational speed N and the induced voltage E ₀ and the induced voltage constant K _E of the motor, the motor current I a relational expression of the rotational speed N Q = K · (I / N). Therefore, since the air volume can be calculated from the current and the rotation speed by the air volume calculating means 8, it is possible to control the driving means 4 from the power instruction means 9 so that the air volume becomes substantially constant. K is a proportional constant, and is determined by fan efficiency and motor efficiency.

  In addition to calculating the operation air volume Q by calculation, the air flow control means 7 is made to actually operate the ventilation air blower with a substantially constant air volume in accordance with the relationship between the operation air volume Q, the motor current I, and the rotation speed N in advance. It can also be stored and realized.

  In the above configuration, the current flowing through the brushless DC motor 16 flows to the stator 1 via the inverter circuit 5 and then flows to the shunt resistor Rs, so that a voltage VRs is generated at both ends of the shunt resistor Rs. The voltage VRs is filtered by a filter circuit, amplified by a gain by the amplifier circuit 12, and becomes a substantially constant DC voltage. Here, the frequency according to the effective current predetermined by the offset voltage of the operational amplifier (not shown) of the filter circuit 10 and the amplifier circuit 12, the saturation voltage, resistance, and capacitor of the semiconductor (not shown), for example, Thus, an accurate pulse cannot be obtained so that a desired frequency of 300 Hz is detected at 310 Hz when an effective current of 0.5 A flows. Here, the pulse converter 13 divides the oscillation frequency of the oscillation circuit 11 and changes the frequency according to the signal of the amplification circuit 12.

  On the other hand, in a semi-finished product state of the motor drive device and the current detection means 6, an arbitrary carrier frequency, for example, 20 kHz at the same frequency as the PWM drive output from the drive means 4 and an effective value of 0. The trimming resistor 14 is trimmed with a laser while monitoring the output pulse signal of the current detection means 6 by flowing a current of 5 A, and the desired trimming is performed by changing the resistance value and adjusting the output signal to a desired value. For example, an output within 300 Hz ± 1% with respect to 300 Hz can be obtained. Here, by setting the frequency to several hundred Hz, the air volume control means 7 can be a general-purpose inexpensive microcomputer.

  The brushless DC motor configured as described above and the ventilation blower equipped with the brushless DC motor can suppress variations in the current detection means 6 and can detect the current with higher accuracy and accuracy with a simple and inexpensive configuration. The air volume can be controlled to be substantially constant.

  Further, the output signal of the pulse converter 13 may be set to a constant carrier frequency, and the duty may be varied without causing a difference in the operation effect.

  Further, the current can be detected with higher accuracy by functionally trimming a constant such as a resistor that determines the oscillation frequency of the oscillation circuit 11.

  Further, if an insulation circuit (not shown), for example, an electrical insulation component such as a photocoupler, is provided at the subsequent stage of the pulse converter 13, it can be electrically insulated from the air volume control means 7, and is generated by driving the motor. An adverse effect due to noise propagation can be suppressed.

  In the first embodiment, the current detection means 6 is adjusted so as to obtain a pulse signal corresponding to the effective value of the current by performing functional trimming with a laser. Does not occur. Moreover, it cannot be overemphasized that adjustment including the dispersion | variation of the whole apparatus is also possible by adjusting in the state of a ventilation ventilation apparatus.

(Embodiment 2)
A second embodiment of the present invention will be described with reference to FIG.

  FIG. 4 is a diagram showing the structure of the brushless DC motor of the present invention.

  In FIG. 4, the mold resin 18 is, for example, a thermosetting resin whose main component is an unsaturated polyester and has a good thermal conductivity. The stator 1, the position detection means 3 on the circuit board 3, the inverter circuit 5, and the current detection means 6 are integrated with a mold resin 18 that forms the outline of the brushless DC motor 16. Further, the trimming resistor 14 and lands and pins as a monitor terminal (not shown), which are a part of the current detection means 6, are exposed.

  In the above configuration, at least the position detection means 3, the inverter circuit 5, and the current detection means 6 are integrated with the stator 1 by a mold resin 18 that also serves as an outer shell and has good heat dissipation. An inexpensive one can be selected. Furthermore, by integrating the current detection means 6 and other electronic components, wiring such as lead wires and circuit cases can be omitted. Further, since the trimming resistor 14 which is a part of the current detection unit 6 is exposed from the mold resin 18, the trimming resistor 14 is trimmed by a laser while monitoring the output pulse signal of the current detection unit 6 after the motor is completed. It is possible to perform functional trimming to change the value and adjust the output pulse signal to a desired value.

  The brushless DC motor configured as described above and the ventilation blower equipped with the brushless DC motor can be reduced in size and simplified by integrating a part of the control circuit with the motor by a resin mold having good heat dissipation. A brushless DC motor capable of controlling a constant air volume substantially constant is obtained.

  In this embodiment, the mold resin is a thermosetting resin whose main component is an unsaturated polyester. However, it may be ultraviolet curable or thermoplastic, and if it is an insulator having a high thermal conductivity, the main component is the main component. It does n’t matter.

  Further, in the first embodiment, in addition to the example using the current detection means 6 and the trimming resistor 14, adjustment by volume resistance may be performed. However, when the current detection means 6 is sealed with mold resin, the trimming resistor 14 The current detection means 6 using the above has improved productivity, and it is easy to control the air volume substantially constant with a simple structure with higher accuracy while suppressing variations.

  The brushless DC motor of the present invention is a refrigerator, dehumidifier, in addition to a ventilation fan such as a ventilation fan or a bathroom dryer equipped with a brushless DC motor capable of controlling the air flow with high accuracy and suppressing variations in current detection. It can also be applied to household electrical appliances such as air conditioners.

DESCRIPTION OF SYMBOLS 1 Stator 2 Rotor 3 Position detection means 4 Drive means 5 Inverter circuit 6 Current detection means 7 Air volume control means 8 Air volume calculation means 9 Power instruction means 10 Filter circuit 11 Oscillation circuit 12 Amplifier circuit 13 Pulse converter 14 Trimming resistor 15 Casing 16 Brushless DC motor 17 Blower fan 18 Mold resin

Claims (12)

A stator having a winding wound thereon, a rotor provided with a magnet, position detection means for detecting a relative position of the magnet with respect to the stator, an inverter circuit for energizing the stator with a DC voltage, and Drive means for driving the inverter circuit to rotate the rotor and outputting a rotation signal according to the position of the magnet detected by the position detection means, and current flowing in the winding via the inverter circuit An air flow rate for controlling the current flowing through the stator based on the relationship between the current detection means for converting to a pulse signal corresponding to the effective value, and the rotation signal output from the drive means and the pulse signal output from the current detection means. A brushless DC motor driving device configured with arithmetic means. 2. The brushless DC motor driving apparatus according to claim 1, wherein the current detection means performs functional trimming based on an arbitrary effective value current. 3. The brushless DC motor driving apparatus according to claim 1, wherein the current detection means performs functional trimming based on an effective value current having a carrier frequency equal to or higher than an audible range and less than duty 100%. 4. The brushless DC motor driving apparatus according to claim 1, wherein the current detection means performs functional trimming on an oscillation circuit for a pulse signal to be output. 5. A brushless DC motor driving apparatus according to claim 1, wherein the pulse signal output from the current detection means changes in frequency according to an effective value current. 6. The brushless DC motor driving apparatus according to claim 1, wherein the duty of the pulse signal output from the current detecting means changes according to the effective value current. The brushless DC motor driving device according to any one of claims 1 to 6, wherein the frequency of the pulse signal of the current detection means is several hundred Hz. 8. The brushless DC motor driving apparatus according to claim 1, wherein the current detection means includes an insulating circuit. 9. The brushless DC motor driving apparatus according to claim 1, wherein the brushless DC motor comprises at least a position detection means, an inverter circuit, and a current detection means integrated with a stator. 10. The brushless DC motor driving apparatus according to claim 9, wherein the brushless DC motor is integrated with the stator by a mold resin that also serves as an outer shell. The brushless DC motor driving device according to claim 10, wherein at least part of the current detection means is exposed in the brushless DC motor. A ventilation blower equipped with the brushless DC motor driving device according to any one of claims 1 to 11.

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