JP5063570B2 - Fan drive device and air conditioner equipped with the same - Google Patents

Description

  The present invention relates to a fan drive device, and more particularly to a fan installed in an environment receiving wind from outside such as outdoors.

  As a conventional fan driving device, there is one that suppresses a DC voltage increase by adjusting the phase of the output voltage for the purpose of avoiding circuit damage caused by a fan using a permanent magnet motor rotating at high speed due to strong wind. It is disclosed (for example, see Patent Document 1).

Japanese Patent Laying-Open No. 2008-160916 (pages 4, 5 and 1)

However, the fan drive device described above performs a protective operation from the concern that it exceeds the circuit rating when the electromotive voltage is generated between the terminals by being rotated by a strong wind and the electromotive voltage exceeds the DC voltage of the inverter. However, there is a problem that the rotational energy due to the strong wind is consumed without being used in the apparatus, and the energy cannot be used.
In addition, since an outdoor unit to which a plurality of indoor units are connected needs to respond to the operation request of any indoor unit, a power source for standby is necessary, and there is a problem that energy is wasted due to this standby power. is there.

  The present invention has been made to solve the above-described problems, and regenerates and uses the energy of electromotive force generated by the rotation of a fan generated by outside wind to realize standby power reduction and power consumption reduction. It aims at obtaining a fan drive device.

A fan driving device according to the present invention is driven by a converter that rectifies and smoothes an AC power source and generates a DC voltage in a smoothing capacitor, an inverter that converts a DC voltage generated by the converter into an AC voltage, Permanent magnet type synchronous motor for rotationally driving the connected fan, rotational speed detecting means for detecting the rotational speed of the fan, voltage detecting means for detecting the voltage across the smoothing capacitor, and input current or output of the inverter Current detecting means for detecting current; and control means for PWM controlling the opening / closing operation of the switching element of the inverter, wherein the control means converts the rotational power received by the fan by the external wind into electric energy and converts the smoothness Regenerative operation mode for storing electric power in a capacitor and the rotational power of the fan as electrical energy Has converted two modes of operation of the constant voltage operation mode for controlling so as to hold the voltage across the smoothing capacitor to a predetermined value, have a operation mode switching means for switching the two operation modes, the operation mode The switching means switches to the constant voltage operation mode when the rotation speed detected by the rotation speed detection means is higher than a predetermined rotation speed or when the both-end voltage detected by the voltage detection means is higher than a predetermined voltage. Switching, when the rotational speed detected by the rotational speed detection means is less than or equal to a predetermined rotational speed and the voltage across the terminals detected by the voltage detection means is lower than or equal to a predetermined voltage, the control means is switched to the regenerative operation mode. Is the both-end voltage detected by the voltage detection means and the current detected by the current detection means in the regenerative operation mode. Regenerative power is calculated repeatedly based on this, and when the regenerative power calculated this time is larger than the regenerative power calculated last time, the duty ratio of the PWM control of the inverter is increased, and the regenerative power calculated this time is calculated last time. The duty ratio of PWM control of the inverter is reduced when the regenerative power is equal to or less .

  According to the fan drive device of the present invention, it is possible to regenerate the electromotive force energy generated by the rotation of the fan generated by the external wind, and to realize standby power reduction and power consumption reduction. In addition, since the components related to the realization are elements that are normally provided in the motor drive device, such as an inverter, a rotation detection means, and a DC voltage detection means, it can be realized at a very low cost.

Embodiment 1 FIG.
(Overall configuration of fan drive unit)
FIG. 1 is a configuration diagram of a fan drive device according to Embodiment 1 of the present invention.
In FIG. 1, an AC power source 1 is connected to a converter 2 that converts the AC voltage into a DC voltage, and a DC / DC converter 3 is connected to the output side of the converter 2 as a load. Further, an inverter 4 for converting a DC voltage output from the converter 2 into an AC voltage is connected to the output side of the converter 2. Current detection means 13 is installed on the input side of the inverter 4, and thereby the current Idc input to the inverter 4 is detected. The current detection means 13 may be installed on the output side of the inverter 4 to detect the output current of the inverter 4. A brushless DC motor 5, which is a permanent magnet type synchronous motor, is connected to the output side of the inverter 4 and is driven to rotate by an AC voltage output from the inverter 4. A fan 6 is connected to the rotation shaft of the brushless DC motor 5, and rotates with the rotation of the brushless DC motor 5 to generate wind force (hereinafter referred to as fan wind). Further, the brushless DC motor 5 is provided with a rotational speed detecting means 14 for detecting the rotational speed N of the fan 6. The converter 2 is connected to the reactor 9 connected to the AC power supply 1, the rectifying means 10 connected to the AC power supply 1 via the reactor 9, and the voltage output from the rectifying means 10 connected to the output side of the rectifying means 10. It is comprised by the smoothing capacitor 11 which smoothes. DC voltage detecting means 12 is connected to both ends of the smoothing capacitor 11 to detect the voltage Vdc across the smoothing capacitor 11. The inverter 4 is a three-phase bridge type inverter configured by switching elements 15a to 15f and diodes 16a to 16f. Moreover, the control means 7 which inputs the operation command from the outside, outputs a control signal with respect to the switching elements 15a-15f of the inverter 4 based on the command, and carries out PWM control of the opening / closing operation | movement is provided. The control means 7 includes a voltage Vdc across the smoothing capacitor 11 detected by the DC voltage detection means 12, a current Idc detected by the current detection means 13, and the rotational speed N of the fan 6 detected by the rotational speed detection means 14. Enter a value for. Further, the control means 7 includes an operation mode switching means 8 for switching between a regenerative operation mode and a constant voltage operation mode, which will be described later, and a memory 17 for storing control information and the like. The memory 17 may be provided outside the control unit 7 so that information is transmitted to and received from the control unit 7. The above-described converter 2, DC / DC converter 3, inverter 4, brushless DC motor 5, control means 7, DC voltage detection means 12, current detection means 13 and rotation speed detection means 14 constitute a fan drive device 31.

(Regenerative operation of fan drive unit)
FIG. 2 is a flowchart showing the operation of the control means 7 when the fan driving device receives external wind. Here, the outside wind referred to in the present invention is not the fan wind generated by the rotation of the fan 6 but the wind received by the fan 6 from the outside as shown in FIG. In general, the fan 6 has an external operation command ON state (with a rotation request) and an OFF state (no rotation request). When the operation command is ON, the control means 7 However, since the present invention is based on the premise that the operation command is OFF, only the operation in this case will be described. Hereinafter, the operation of the fan driving device 31 will be described with reference to FIGS. 2 and 3.

  First, the control means 7 initializes the PWM duty ratio and the PWM increase / decrease flag stored in the memory 17 (step S1). Next, it is determined whether or not an external operation command is OFF (step S2). As a result of the determination, if the operation command is ON, it is a normal fan drive operation, so the in-control flag described later is turned OFF (step S4), and the process ends. On the other hand, when the operation command is OFF, it is determined whether or not the rotational speed N of the fan 6 is larger than the power generation maintenance lower limit rotational speed Nen, which is the minimum rotational speed capable of maintaining power generation (step S3). As a result of the determination, when the rotation speed N is equal to or lower than the power generation maintenance lower limit rotation speed Nen, a control flag to be described later is turned OFF (step S4), and the process is terminated. On the other hand, when the rotation speed N is larger than the power generation maintenance lower limit rotation speed Nen, the previous regenerative power P (t−1) stored in the memory 17 is updated with the latest regenerative power P (t), and the DC voltage detection means 12 is updated. Based on the both-end voltage Vdc detected by the current detection unit 13 and the current Idc detected by the current detection unit 13, the current (time t) regenerative power is calculated and newly stored in the memory 17 as the latest regenerative power P (t). (Step S5).

  Next, it is determined whether power generation is possible by comparing the rotation speed N with the cut-in rotation speed Nci that enables power generation by external wind (step S6). As a result of the determination, if the rotational speed N is equal to or lower than the cut-in rotational speed Nci, it is determined that the rotational speed of the fan 6 for power generation is insufficient, and it is determined whether the in-control flag is ON (step) S7). As a result of the determination, if this in-control flag is OFF, the in-control flag is turned ON (step S8), the PWM duty ratio is set to 0%, the PWM increase / decrease flag is set to “increase”, and the memory 17 is set. (Step S9), the PWM duty ratio is set to 0%, PMW control, that is, a PWM control signal for turning off the switching elements 15d to 15f on the lower arm side of the inverter 4 is output (step S15), and the process returns to step S2. . On the other hand, if this in-control flag is ON, the process proceeds to step S10 described later. In step S7, if the rotational speed N is greater than the cut-in rotational speed Nci, whether the rotational speed N is greater than the cut-out rotational speed Nco that cannot generate power due to the strong external wind, or a smoothing capacitor 11 is determined whether the both-ends voltage Vdc of 11 is larger than the predetermined voltage upper limit value Vdcmax (step S10). As a result of the determination, when the rotation speed N is larger than the cut-out rotation speed Nco or the both-ends voltage Vdc is larger than the voltage upper limit value Vdcmax, the PWM duty ratio is set to 100% and the PWM increase / decrease flag is “decreased”. Is stored in the memory 17 (step S11), the PWM duty ratio is set to 100%, PWM control, that is, a PWM control signal for turning on the switching elements 15d to 15f on the lower arm side of the inverter 4 is output, and brushless The terminals of the DC motor 5 are electrically short-circuited (step S15), and the process returns to step S2. At this time, since no voltage is generated in the terminal voltage of the brushless DC motor 5, there is no regeneration of power to the smoothing capacitor 11, and the voltage Vdc at both ends thereof does not increase. On the other hand, when the rotational speed N is equal to or lower than the cut-out rotational speed Nco and the both-ends voltage Vdc is equal to or lower than the voltage upper limit value Vdcmax, the regenerative operation by the hill-climbing method is performed by operating in the regenerative operation mode described below. Is done. First, the latest regenerative power P (t) is compared with the previous regenerative power P (t-1) (step S12). If the latest regenerative power P (t) is equal to or lower than the previous regenerative power P (t−1) as a result of the comparison, the PWM increase / decrease flag is inverted and stored in the memory 17 (step S13), and based on the PWM increase / decrease flag. The PWM duty ratio is calculated and stored in the memory 17 (step S14). On the other hand, when the latest regenerative power P (t) is larger than the previous regenerative power P (t−1), the PWM increase / decrease flag is left as it is, and the PWM duty ratio is calculated and stored in the memory 17 (step S14). After calculating the PWM duty ratio in step S14, a PWM control signal is output based on the PWM duty ratio (step S15). It is controlled to regenerate at the maximum power point by the above regenerative operation mode. At this time, since the above-mentioned regenerative power flows into the DC / DC converter 3, which is a load connected in parallel to the smoothing capacitor 11, the power supply from the AC power supply 1 is reduced, and the power consumption of the fan driving device is reduced. Is suppressed.

  In step S10, when the voltage Vdc across the smoothing capacitor 11 is an overvoltage, that is, Vdc> Vdcmax, Vdc gradually decreases due to power consumption of the DC / DC converter 3 that is a load. Thereafter, when the both-end voltage Vdc becomes equal to or lower than the voltage upper limit value Vdcmax, the regenerative operation is performed again, the both-end voltage Vdc rises, and the both-end voltage Vdc is controlled to be a constant voltage by repeating this. Here, the operation mode in which the both-end voltage Vdc is maintained at a constant voltage is referred to as a constant voltage operation mode. As described above, the regenerative operation mode that is controlled so as to perform the regenerative operation at the maximum regenerative power point that can generate power in the state of the wind speed of the external wind and the constant voltage operation mode that maintains the both-end voltage Vdc at a constant voltage are controlled. The regenerative operation is performed by appropriately switching by the operation mode switching means 8 of the means 7.

  In step S10, the determination is performed based on the value of the rotational speed N of the fan 6 and the voltage Vdc across the smoothing capacitor 11. However, the present invention is not limited to this, and only the rotational speed N or only the voltage Vdc across the voltage is detected. The determination may be performed based on the current Idc, or may be performed based on the current Idc detected by the current detection unit 13.

FIG. 3 is a time chart showing the operation of the control means when the fan driving device receives external wind. Hereinafter, the behavior of the rotational speed N of the fan 6, the regenerative power, the both-ends voltage Vdc of the smoothing capacitor 11, etc. when the wind speed of the outside wind changes will be described with reference to FIG.
First, when outside wind is generated, the rotational speed N of the fan 6 increases, and when the rotational speed N reaches the cut-in rotational speed Nci, the PWM duty ratio is gradually increased, power generation is started, and the regenerative power is also increased. The smoothing capacitor 11 is charged and the voltage Vdc across the terminal increases. When the vicinity of the maximum regenerative power point that can generate power in the state of the wind speed of the outside wind, the PWM duty ratio repeatedly increases and decreases and stabilizes at a substantially maximum efficiency operating point. When the outside wind speed further increases and the both-end voltage Vdc increases to reach the voltage upper limit value Vdcmax, the PWM duty ratio is 100%, that is, the switching elements 15d to 15f on the lower arm side of the inverter 4 are turned on, and the regenerative power Is set to 0 and operates to suppress the increase in Vdc.

(Effect of Embodiment 1)
With the configuration and operation as described above, it is possible to regenerate the electromotive force energy generated by the rotation of the fan 6 caused by the external wind, and it is possible to reduce standby power consumption and power consumption.
Moreover, since the components related to the realization are elements provided in a normal motor driving device such as an inverter, a rotation speed detection means, and a DC voltage detection means, it can be realized at a very low cost.
Since the voltage Vdc across the smoothing capacitor 11 charged by the regenerative operation by the rotation of the fan 6 can be controlled to a constant voltage, circuit damage due to overvoltage can be avoided.
Further, in the first embodiment, only the lower arm of the inverter 4 is used as the control method for the regenerative power and the both-end voltage Vdc, so that the both-end voltage Vdc is low and the drive voltage of the upper arm of the inverter 4 is insufficient. Operation is possible and a highly reliable device can be obtained.

The above regenerative operation is performed by PWM control only for the lower arm in the inverter 4, but is not limited to this, and can also be performed by PWM control only for the upper arm.
Moreover, although PWM control of a switching element is used as a control method of this regenerative operation, it is not limited to this, and it is also possible by voltage phase phase shift control implemented in the blower driving device according to Patent Document 1. It is.

Embodiment 2. FIG.
(Overall configuration of air conditioner)
FIG. 4 is a circuit configuration diagram of an air conditioner according to Embodiment 2 of the present invention, and FIG. 5 is an external perspective view of an outdoor unit in the air conditioner.
The refrigerant flow path circulating in the air conditioner according to Embodiment 2 passes through the compressor 32, the four-way valve 33, the outdoor unit heat exchanger 34, the expansion valve 35, the indoor unit heat exchanger 36, and again through the four-way valve 33. Then, the refrigerant pipes are connected in the order of returning to the compressor 32. The outdoor unit heat exchanger 34 is provided with a fan 6, and the fan 6 is connected to a fan driving device 31. The fan drive device 31 receives supply of AC voltage from the AC power source 1. An indoor fan 37 is installed in the indoor unit heat exchanger 36, and the indoor fan 37 is connected to an indoor fan motor 38. The compressor 32, the four-way valve 33, the outdoor unit heat exchanger 34, the fan driving device 31, and the fan 6 constitute the outdoor unit 21, and the expansion valve 35, the indoor unit heat exchanger 36, and the indoor fan 37. The indoor unit 22 is configured by the indoor fan motor 38.

(Basic operation of air conditioner)
The refrigerant flowing into the compressor 32 is compressed and becomes a high-temperature and high-pressure gas refrigerant, and is sent to the outdoor unit heat exchanger 34 via the four-way valve 33. The gas refrigerant that has flowed into the outdoor unit heat exchanger 34 is subjected to heat exchange with the air fed by the fan 6 that is rotated by the drive of the fan driving device 31, condensed to become a liquid refrigerant, and is sent to the expansion valve 35. The liquid refrigerant flowing into the expansion valve 35 is reduced in pressure to become a low-pressure two-phase refrigerant and sent to the indoor unit heat exchanger 36. The two-phase refrigerant that has flowed into the indoor unit heat exchanger 36 undergoes heat exchange with the air sent by the indoor fan 37 that is rotated by the drive of the indoor fan motor 38, evaporates into a gas refrigerant, and passes through the four-way valve 33. Then, it is sent to the compressor 32 again. Thereafter, the above operation is repeated.

  As shown in FIG. 5, when the fan 6 of the outdoor unit 21 receives external wind from the outside, the fan 6 receives rotational power, and an electromotive force is generated inside the fan driving device 31 along with the rotation. A regenerative operation similar to that in Embodiment 1 is performed.

(Power supply wiring form for air conditioner)
FIG. 6 is a diagram illustrating an example of a power supply wiring form of the air conditioner.
6A is a diagram illustrating an indoor unit power receiving type in which the indoor unit 22 receives AC power from a commercial power supply via the outlet 25 and supplies power to the outdoor unit 21, and FIG. 6B is a diagram illustrating the outdoor unit. 21 is a diagram showing an outdoor unit power receiving type in which AC power is received from a commercial power source via an outlet 25 and power is supplied to the indoor unit 22, and FIG. It is a figure which shows the independent power receiving type which receives alternating current power from a commercial power source independently via. At this time, in any of the power supply wiring forms, control by a controller (not shown), a remote controller, or the like is performed on the indoor unit 22 side, so that the indoor unit 22 needs a power supply for always being in a standby state. In the case of (a), when the indoor unit 22 detects the operation command and supplies power to the outdoor unit 21 and transmits the operation command, the standby power of the outdoor unit 21 can be easily reduced to zero. Can be realized. In the case of (b) and (c), since the outdoor unit 21 is directly supplied with power from a commercial power source, standby power cannot be saved and energy loss occurs.

  The air conditioner according to the second embodiment has a power supply wiring configuration shown by (b) or (c) in FIG. 6, and an outdoor unit is performed by performing the same regenerative operation as in the first embodiment. The standby power generated at 21 is reduced. In addition, as shown in (b) or (c) in FIG. 6, the outdoor unit 21 may be shared, and a plurality of indoor units 22 may be installed.

(Effect of Embodiment 2)
With the configuration and operation described above, an air conditioner that can regenerate the energy of the electromotive force generated by the rotation of the fan 6 generated by the outside wind as in the first embodiment and realizes standby power reduction and power consumption reduction is obtained. be able to.
Further, in the power supply wiring forms shown in (b) and (c) in FIG. 6, since the ratio of the standby power of the outdoor unit to the total power consumption of the air conditioner is large, the regenerative power generated by the rotation of the fan 6 Therefore, the effect of reducing standby power consumption and power consumption is great.

  Although the standby power reduction effect of the air conditioner has been exemplified in the second embodiment, it can be widely applied as long as the outdoor blower is an independent power receiving system. For example, it can be applied to a heat pump water heater or a defrost fan. Is possible.

It is a block diagram of the fan drive device which concerns on Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the control means when the fan drive device is receiving external wind. It is a time chart which shows operation | movement of the control means when the fan drive device receives the external wind. It is a circuit block diagram of the air conditioner which concerns on Embodiment 2 of this invention. It is an external appearance perspective view of the outdoor unit in the air conditioner. It is a figure which shows the example of the power supply wiring form of the air conditioner.

Explanation of symbols

1 AC power supply, 2 converter, 3 DC / DC converter, 4 inverter, 5 brushless DC motor, 6 fan, 7 control means, 8 operation mode switching means, 9 reactor, 10 rectifying means, 11 smoothing capacitor, 12 DC voltage detecting means , 13 Current detection means, 14 Rotation speed detection means, 15a to 15f Switching element, 16a to 16f Diode, 17 Memory, 21 Outdoor unit, 22 Indoor unit, 25 Outlet, 31 Fan drive unit, 32 Compressor, 33 Four-way valve, 34 outdoor unit heat exchanger 35 expansion valve, 36 indoor unit heat exchanger, 37 indoor fan, 38 indoor fan motor.

Claims (5)

A converter that rectifies and smoothes an AC power supply and generates a DC voltage in a smoothing capacitor;
An inverter that converts a DC voltage generated by the converter into an AC voltage;
A permanent magnet type synchronous motor driven by the inverter and rotationally driving a connected fan;
A rotational speed detection means for detecting the rotational speed of the fan;
Voltage detecting means for detecting a voltage across the smoothing capacitor;
Current detecting means for detecting an input current or an output current of the inverter;
Control means for PWM control of the switching operation of the switching element of the inverter;
With
The control means includes
Regenerative operation mode in which the rotational power received by the fan by the external wind is converted into electric energy and electric power is stored in the smoothing capacitor, and the rotational power of the fan is converted into electric energy and the voltage across the smoothing capacitor is held at a predetermined value. Has two operation modes of constant voltage operation mode to control,
Have a operation mode switching means for switching the two operation modes,
The operation mode switching means is
When the rotational speed detected by the rotational speed detection means is higher than a predetermined rotational speed, or when the both-end voltage detected by the voltage detection means is higher than a predetermined voltage, switching to the constant voltage operation mode,
When the rotational speed detected by the rotational speed detection means is equal to or lower than a predetermined rotational speed, and the both-end voltage detected by the voltage detection means is equal to or lower than a predetermined voltage, switching to the regenerative operation mode,
The control means includes
In the regenerative operation mode,
Based on the both-end voltage detected by the voltage detection means and the current detected by the current detection means, regenerative power is repeatedly calculated,
When the regenerative power calculated this time is larger than the regenerative power calculated last time, the duty ratio of PWM control of the inverter is increased,
The fan drive device according to claim 1, wherein when the regenerative power calculated this time is equal to or less than the regenerative power calculated last time, a duty ratio of PWM control of the inverter is decreased . Wherein, the in the regeneration operation mode, according to claim 1 Symbol placement of the fan drive, characterized in that PWM control the opening and closing operation of the switching elements in only or only the upper arm lower arm of the inverter. It is composed of an outdoor unit, an indoor unit, and a refrigerant pipe connecting the outdoor unit and the indoor unit,
The said outdoor unit is provided with the fan drive device of Claim 1 or Claim 2. The air conditioner characterized by the above-mentioned. The air conditioner according to claim 3 , wherein the number of the outdoor units is one, and the number of the indoor units is plural. The air conditioner according to claim 3 or 4 , wherein the outdoor unit is directly supplied with power from a commercial power source.

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