JP6255573B2 - Ventilation equipment - Google Patents

Description

  The present invention relates to an air volume control method for a ventilator such as a fan motor or a ventilator that performs inverter control of an air conditioner or the like.

  A conventional control circuit of this type of blower has the following configuration. First, AC power from an AC power source is converted from AC to DC by an AC / DC converter circuit and smoothed by a capacitor. A DC voltage is generated at both ends of the capacitor and is input to the inverter via the current detector. The six semiconductors constituting the inverter are operated (switched) with each other to drive the motor. Since the current flowing through the motor flows through the inverter and the current detector, the current is detected by the voltage induced at both ends of the current detector.

  The position sensor is mounted so as to generate a signal corresponding to the position of the rotor due to the rotation of the motor. The rotational speed detection unit detects the rotational speed of the motor based on a signal from the position sensor. The rotation speed detected here is output to the air volume calculation unit and the speed control unit. The air volume calculation unit calculates the air volume generated by the fan connected to the motor from the motor current value detected by the current detection unit and the motor rotation speed detected by the rotation speed detection unit. To do.

  In the air volume calculation unit, the air volume calculation unit calculates the air volume from the rotation speed detected by the rotation speed detection unit and the current detected by the current detection unit, and the calculated air volume and target air volume calculated by the target rotation speed calculation unit. And a target rotational speed that is a target of motor operation is calculated so that the deviation becomes zero. The speed controller controls the speed of the motor so as to achieve the target rotational speed calculated by the air volume calculator. Therefore, since the air volume generated by the fan connected to the motor matches the target air volume, the air volume is controlled to be constant (for example, Patent Document 1 below).

JP 2002-165477 A

  In such a conventional blower, the air volume is calculated using the current and the rotational speed, but the current detection unit combines the negative potential side terminals of the switching elements constituting the lower stage of the inverter circuit into one. It was configured to be connected between the location and the circuit ground.

  As a problem in such a blower, the current of the motor is measured by the current detection unit, but since it is connected to the circuit ground, the motor current can be detected only by the three-phase combined current, and the switching element is In the case of a driver assembly, there is a problem that a current necessary for the driver is detected and an accurate motor phase current cannot be detected.

  Furthermore, when the air blower is operated with a large air volume, the current flowing through the circuit is large (eg, 1.2 A). On the other hand, the current required for the driver is about 10 mA, which is a small proportion and does not affect the air volume. However, when operating with a small air volume, the current flowing in the circuit is small (about 30 mA), and the ratio of the current (10 mA) necessary for the driver is large. Therefore, the detected current includes a large error with respect to the current value corresponding to the actual air volume, and cannot be accurately controlled with respect to the air volume.

  Further, when the blower is operated with a small air volume, since the current flowing through the circuit is small, the recognition error becomes large with respect to the current value with respect to the actual air volume, and it cannot be controlled with high accuracy.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object thereof is to provide a ventilator that accurately detects a current flowing through a motor and accurately controls the air flow with respect to a target air flow.

In order to achieve this object, the present invention is a ventilation device that can vary the air volume,
The ventilation device includes a motor for driving the blades and a control circuit for controlling the motor. The control circuit includes two switching elements that are in an upper stage and a lower stage and perform opposite ON / OFF operations. Three arms connected in series with a DC voltage are connected in a three-phase bridge shape, and an inverter circuit for applying a three-phase PWM AC voltage to the motor, and a commercial power source is rectified and smoothed to the inverter circuit, and then desired. A power supply circuit having a DC voltage varying means for generating a DC voltage, a shunt resistor inserted for each phase between the lower stage and the negative potential side of each phase of the inverter circuit, and a voltage between terminals of the shunt resistor are amplified. An amplifying unit, a current detecting unit for detecting a current of each phase flowing from the output of the amplifying unit to the motor, and a rotation speed of the motor based on the current detected by the current detecting unit. A rotation detection unit for calculating a location,
A target air quantity instruction unit for instructing the target airflow, and the current value of any one phase of the current value of each phase detected by the current detection unit, the rotational speed and to the input of the currently to the rotation detecting section is calculated Based on the comparison result of the air volume calculation unit that calculates the output air volume and compares the calculated output air volume with the target air volume , the duty is varied with respect to the inverter circuit, and the motor A speed control unit for controlling the number of rotations, and the DC voltage varying means achieves an intended purpose by varying a DC voltage output according to a target air volume indicated by the target air volume indicating unit. It is.

As described above, the present invention is a ventilation device capable of changing the air volume,
The ventilation device includes a motor for driving the blades and a control circuit for controlling the motor. The control circuit includes two switching elements that are in an upper stage and a lower stage and perform opposite ON / OFF operations. Three arms connected in series with a DC voltage are connected in a three-phase bridge shape, and an inverter circuit for applying a three-phase PWM AC voltage to the motor, and a commercial power source is rectified and smoothed to the inverter circuit, and then desired. A power supply circuit having a DC voltage varying means for generating a DC voltage, a shunt resistor inserted for each phase between the lower stage and the negative potential side of each phase of the inverter circuit, and a voltage between terminals of the shunt resistor are amplified. An amplifying unit, a current detecting unit for detecting a current of each phase flowing from the output of the amplifying unit to the motor, and a rotation speed of the motor based on the current detected by the current detecting unit. A rotation detection unit that calculates a position; a target air volume instruction unit that indicates a target air volume; and a current value of one phase among current values detected by the current detection unit, and the rotation detection unit The current output air volume is calculated by inputting the rotational speed, and the inverter circuit is compared with the air volume calculating unit that compares the calculated output air volume with the target air volume, and the comparison result of the air volume calculating unit. In contrast, a speed control unit that controls the rotational speed of the motor by varying the duty is provided, and the DC voltage varying means varies the DC voltage output according to the target air volume indicated by the target air volume indicating unit. Only the current flowing in the motor winding can be detected directly, and the DC voltage to be output can be varied according to the target air volume. Electricity flowing in the wire Increases the current value recognized by the air flow calculation unit and reduces the recognition error, so that the motor winding current can be detected accurately and the ventilation air flow is always kept constant. And, there is an effect that wasteful energy can be reduced.

Installation drawing showing the ventilation device installed on the ceiling Block diagram showing the configuration of the control circuit of the ventilator Flow chart showing operation of the ventilator

The ventilator according to claim 1 of the present invention is a ventilator capable of changing the air volume,
The ventilation device includes a motor for driving the blades and a control circuit for controlling the motor. The control circuit includes two switching elements that are in an upper stage and a lower stage and perform opposite ON / OFF operations. Three arms connected in series with a DC voltage are connected in a three-phase bridge shape, and an inverter circuit for applying a three-phase PWM voltage to the motor, and a commercial power source is rectified and smoothed in the inverter circuit and then desired. A power supply circuit having DC voltage varying means for generating a DC voltage, a shunt resistor inserted for each phase between the lower stage and the negative potential side of each phase of the inverter circuit, and a voltage between terminals of the shunt resistor are amplified. An amplifying unit; a current detecting unit for detecting a current of each phase flowing to the motor from the output of the amplifying unit; and a rotational speed and a position of the motor based on the current detected by the current detecting unit A rotation detection unit to be calculated, a target air volume instruction unit for instructing a target air volume, a current value of one phase among current values detected by the current detection unit, and a rotation speed calculated by the rotation detection unit To calculate the current output air volume, and to compare the calculated output air volume with the target air volume, and to the inverter circuit based on the comparison result of the air volume calculator A speed control unit that controls the number of revolutions of the motor by varying the duty, and the DC voltage varying unit varies the DC voltage that is output according to the target air volume indicated by the target air volume indicating unit. .

  As a result, it is possible to directly detect only the current flowing in the motor winding. Further, based on the target air volume, in the case of a small air volume, the DC voltage can be varied to reduce the current flowing in the motor winding. By increasing the current value recognized by the air flow calculation unit and reducing the recognition error, it is possible to accurately detect the current of the motor winding and keep the ventilation air flow constant at all times. Can do.

The control circuit includes a gain changing means for changing the amplification factor of the amplification unit, the amplification factor changing means has a configuration for switching the amplification factor of the front Symbol amplifying unit based on the target air volume Yes.

  This makes it possible to change the size of the amplification changing means according to the target air volume, accurately detect the current flowing in the motor winding, and keep the ventilation air volume constant even when the target air volume is small. be able to.

In addition, the said control circuit comprises a gain changing means for changing the amplification factor of the amplification unit, the amplification factor changing means, the gain of the pre-Symbol amplifying section based on the current the current detection unit detects It is good also as a structure to switch.

  As a result, the size of the amplification changing means can be changed according to the current detected by the current detection unit, and the current flowing in the motor winding can be accurately detected. Even when the target air volume is small, the ventilation air volume is small. Can always be kept constant.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

(Embodiment 1)
As an embodiment of the ventilator of the present invention, a ventilator provided on a ceiling in a building will be described.

  The ventilator according to the present embodiment takes advantage of the characteristics of the DC motor, performs control from a low speed to a high speed, and covers a single air ventilator from a low air volume to a large air volume.

  As shown in FIG. 1, the ventilator of the present embodiment is installed in the ceiling 2 of the room 1 and has a suction port 3 a below the main body 3. An adapter 4 is provided on the side surface of the main body 3 and is connected to an exhaust port (not shown) provided on an outer wall or the like through an exhaust duct 5. Inside the main body 3, as a motor, there are provided a blade 7 and a sensorless brushless DC motor 8 for rotating the blade 7, and a suction port 3a is provided with a louver 9 covering the suction port 3a. The louver 9 has a vent through which indoor air passes. A control circuit 10 for driving the sensorless brushless DC motor 8 is disposed inside the main body 3 of the ventilation device. A remote control device 11 (a switch formed by integrating a power on / off switch 11a and a fan notch setting switch 11b) is disposed on an indoor wall and connected to the control circuit 10.

  FIG. 2 is a block diagram showing the configuration of the control circuit 10 of the main body 3 of the ventilation device. In FIG. 2, the AC voltage supplied from the commercial power supply 12 is DC converted by the AC / DC converter circuit 13, and then the DC voltage varying means 14 generates a desired DC voltage by a method described later. The generated DC voltage is smoothed by the smoothing capacitor 16 and applied to the inverter circuit 17. The inverter circuit 17 sequentially connects the six switching elements to drive the sensorless brushless DC motor 8. The sensorless brushless DC motor 8 includes a stator 118 around which windings are wound and a rotor 19 having a magnet.

  A shunt resistor 20 is inserted for each phase between the lower stage of each phase of the inverter circuit 17 and the negative potential side. The amplifying unit 21 amplifies the potential difference between both ends of the shunt resistor 20 generated by the current flowing through the shunt resistor 20. From the output of the amplification unit 21, the current detection unit 22 detects the current of each phase flowing through the sensorless brushless DC motor 8. The rotation detector 23 calculates the rotation speed and position of the sensorless brushless DC motor 8 based on the current detected by the current detector 22.

  The air volume calculation unit 24 compares the current detected by the current detection unit 22 with the air volume calculated based on the number of rotations detected by the rotation detection unit 23 with respect to the target air volume Qs described later, and is higher or lower. Determine whether.

  The target air volume instruction unit 25 determines the target air volume Qs in accordance with the setting of the fan notch setting switch 11b. The target air volume instructing unit 25 transmits the target air volume Qs to the air volume calculating unit 24 and also transmits the target air volume Qs to the DC voltage varying unit 14 and the amplification factor changing unit 26. The DC voltage varying means 14 changes the output DC voltage according to the target air volume Qs.

  The amplification factor changing means 26 receives the target air volume Qs determined by the target air volume instruction unit 25, and changes the amplification factor of the amplification unit 21 of a predetermined phase according to the magnitude of the target air volume Qs.

  As will be described in detail later, the speed control unit 27 outputs a duty to the inverter circuit 17 based on a comparison result between the current output air volume Qn output from the air volume calculating unit 24 and the target air volume Qs, and sensorless brushless DC. The number of rotations of the motor 8 is controlled.

  In this way, the sensorless brushless DC motor 8 outputs the necessary air volume by varying the rotation speed.

  Hereinafter, the operation of the ventilation device of the present embodiment will be described with reference to FIG.

  A user operates the remote controller 11 to operate the ventilator to turn on the main body 3 of the ventilator, and sets the fan notch setting switch 11b to, for example, a weak notch. Then, power is applied to the control circuit 10 and the target air volume instruction unit 25 determines the target air volume Qs corresponding to the weak notch according to the setting “weak notch” of the fan notch setting switch 11b. The method for determining the target air volume Qs may be determined with reference to a table stored in the memory, or may be based on a preset calculation formula. This target air volume Qs is transmitted to the air volume calculator 24, the DC voltage varying means 14, and the amplification factor changing means 26.

  The DC voltage varying means 14 changes the DC voltage to be output according to the inputted target air volume Qs.

  Here, the voltage output by the DC voltage varying means 14 is set so as to be an output voltage that can satisfy a predetermined target air volume in the case of a maximum duty (for example, 95%) output in the case of a weak notch. Yes. Thereby, the electric current which flows into the winding of a motor will increase, and the electric current value which the air volume calculating part 24 recognizes will increase.

  When the target air volume Qs is determined, the amplification factor of any one of the three phases is changed by the amplification factor changing means 26 according to the target air volume Qs. The speed control unit 27 outputs a duty to the inverter circuit 17 based on the comparison result between the current output air volume output from the air volume calculating unit 24 and the target air volume Qs.

  When the duty is output to the inverter circuit 17, the six switching elements are sequentially turned on to drive the sensorless brushless DC motor 8. When the sensorless brushless DC motor 8 is driven, a current flows through the shunt resistor 20. The amplifying unit 21 amplifies the potential difference between both ends of each shunt resistor 20. The current detector 22 detects a potential difference between both ends of each amplified shunt resistor 20, and detects a current (winding current) flowing through the motor winding for each phase based on the potential difference. Two phases of the detected winding current are input to the rotation detector 23. As will be described in detail later, the remaining winding current for one phase is input to the air volume calculation unit 24. The rotation detector 23 calculates the rotation speed and position of the sensorless brushless DC motor 8 from the winding currents for two phases.

  Next, the air volume calculation unit 24 calculates the current output air volume Qn from the current value for one phase detected by the current detection unit 22 and the rotation speed detected by the rotation detection unit 23. Then, the air volume calculation unit 24 compares the calculated output air volume Qn with the target air volume Qs. When the output air volume Qn is smaller than the target air volume Qs, the air volume calculator 24 instructs the speed controller 27 to output a large duty. When the output air volume Qn is larger than the target air volume Qs, the air volume calculation unit 24 instructs the speed control unit 27 to output a small duty, and controls to reduce the deviation between the output air volume Qn and the target air volume Qs. Will be.

  Here, when the output air volume Qn is sufficiently small with respect to the rated air volume, the current flowing through the shunt resistor 20 is small, and it is difficult for the current detector 22 to accurately detect the current flowing through the winding current. Therefore, when the target air volume Qs is smaller than the predetermined air volume Qa, the amplification factor changing unit 26 performs a process of increasing the amplification factor of the amplifier 21 for detecting the current value input to the air volume calculator 24. The predetermined air volume Qa is an air volume value stored in advance. This Qa is set to a value that is sufficiently small with respect to the rated air volume and that the current detector 22 cannot accurately detect the winding current unless the amplification factor is switched and detected.

  In the ventilator configured as described above, the current flowing through the sensorless brushless DC motor 8 has a shunt resistor 20 inserted between the lower stage and the negative potential side of each phase of the inverter circuit 17, and the current flowing through the shunt resistor 20. The winding current can be detected with high accuracy by detecting.

  Further, the DC voltage output by the DC voltage varying means 14 is changed according to the target air volume Qs. In particular, in the case of a small air volume, the output DC voltage is reduced to increase the current flowing through the winding of the sensorless brushless DC motor 8. In this way, by increasing the current value recognized by the air volume calculating unit 24 and reducing the recognition error, the current of the motor winding is accurately detected, so that the ventilation air volume can always be kept constant.

  Further, the winding current can be accurately detected by changing the amplification factor of any one of the phases by the amplification factor changing means 26. Accordingly, ventilation from a small air volume to a large air volume utilizing the characteristics of the DC motor can be performed with one main body.

  Further, in the present embodiment, the amplification factor changing means 26 is configured to switch the amplification factor corresponding to the target air volume Qs. However, the amplification factor may be switched based on the current value detected by the current detection unit 22. .

  In this embodiment, the sensorless brushless DC motor 8 is used. However, the gain changing means 26 for switching the gain uses the output of the magnetic sensor to determine the relative position of the rotor 19 with respect to the stator 18. It is also possible to apply to a brushless DC motor that detects the position. That is, the effect is the same in the configuration in which the shunt resistor 20 is connected to any one phase and the amplification factor changing unit 26 switches the amplification factor of the amplification unit 21 that amplifies the potential difference between both ends of the shunt resistor 20.

  Further, although the target air volume instruction unit 25 uses the notch set by the remote control device 11 as an input, a switch may be provided in the main body and the notch set by the switch may be input.

  The ventilation device attached to a building according to the present invention is widely useful in products that can obtain an air volume within a predetermined time regardless of duct resistance and external wind pressure.

DESCRIPTION OF SYMBOLS 1 Indoor 2 Ceiling back 3 Main body 4 Adapter 5 Exhaust duct 7 Blade 8 Sensorless brushless DC motor 9 Louver 10 Control circuit 11 Remote control device 11a Power on / off switch 11b Fan notch setting switch 12 Commercial power supply 13 AC / DC conversion circuit 14 DC voltage variable means DESCRIPTION OF SYMBOLS 15 Power supply circuit 16 Smoothing capacitor 17 Inverter circuit 18 Stator 19 Rotor 20 Shunt resistance 21 Amplifying part 22 Current detection part 23 Rotation detection part 24 Air volume calculating part 25 Target air volume instruction | indication part 26 Amplification rate change means 27 Speed control part

Claims (3)

A ventilation device with variable air volume,
Inside this ventilator,
A motor for driving the blades;
A control circuit for controlling this motor is provided,
In this control circuit,
Three arms consisting of an upper stage and a lower stage and two switching elements that perform opposite ON / OFF operations connected in series to a DC voltage are connected in a three-phase bridge shape, and a three-phase PWM voltage is applied to the motor. An inverter circuit to be applied;
A power supply circuit comprising a DC voltage variable means for generating a desired DC voltage after rectifying and smoothing a commercial power supply in the inverter circuit;
A shunt resistor inserted for each phase between the lower stage of each phase of the inverter circuit and the negative potential side;
An amplifier for amplifying the voltage across the terminals of the shunt resistor;
A current detector for detecting the current of each phase flowing from the output of the amplifier to the motor;
A rotation detector that calculates the rotational speed and position of the motor based on the current detected by the current detector;
A target air volume instruction section for instructing the target air volume;
The current output air volume is calculated by inputting the current value of any one phase among the current values of each phase detected by the current detection unit and the rotation speed calculated by the rotation detection unit, and the calculated output An air volume calculating unit for comparing the air volume with the target air volume ;
Based on the comparison result of the air volume calculation unit, the inverter circuit includes a speed control unit that controls the rotational speed of the motor by varying the duty.
The DC voltage varying means is a ventilator that varies a DC voltage output in accordance with a target air volume indicated by the target air volume indicating unit. The control circuit includes amplification factor changing means for changing the amplification factor of the amplification unit,
The amplification factor changing unit ventilator of claim 1, wherein switching the amplification factor of the front Symbol amplifying unit based on the target air amount. The control circuit includes amplification factor changing means for changing the amplification factor of the amplification unit,
The amplification factor changing unit ventilator of claim 1, wherein switching the amplification factor of the front Symbol amplifying section based on the current the current detection section detects.

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