JP5851935B2 - Refrigeration cycle equipment - Google Patents

Description

  The present invention relates to a refrigeration cycle apparatus in which a compressor motor that drives a compressor and a fan motor that drives a blower fan are connected to a secondary side of a converter circuit via an inverter circuit.

  Conventionally, in an air conditioner or the like in which this type of refrigeration cycle apparatus is used, a compressor motor that drives a compressor in the refrigeration cycle via an inverter circuit on the secondary side of the converter circuit, as in Patent Document 1, and evaporation Some fans were connected to a fan motor that drives a blower fan for blowing air.

  Further, in the air conditioner, in order to perform the defrosting operation of the evaporator, there is one in which the blower fan is delayed and stopped after stopping the compressor, and then the compressor is started to perform the defrosting operation. .

JP 2000-337686 A

  However, in the case where the compressor motor and the fan motor are connected to the secondary side of the converter circuit via the inverter circuit as in Patent Document 1, when the compressor is stopped while the driving of the blower fan is continued, As the voltage on the side increases rapidly, the rotational speed of the fan motor increases temporarily and noise is generated.

In order to solve the above problems, a refrigerant pipe is provided with a compressor that compresses the refrigerant to a high pressure, a radiator that radiates the high-pressure refrigerant, a decompression unit that decompresses and expands the refrigerant from the radiator, and an evaporator that evaporates the low-pressure refrigerant. The refrigeration cycle connected in a ring shape, a blower fan for blowing air to the evaporator, a converter circuit for converting alternating current power into direct current, and a secondary side of the converter circuit are connected via an inverter circuit to drive the compressor A compressor motor that is connected to the secondary side of the converter circuit, drives the blower fan, controls the inverter circuit to drive the compressor motor at a desired rotational speed, and the fan motor Control means for varying a speed command value commanded to the fan motor so as to achieve a desired rotational speed; and the fan mode When stopping the driving of the compressor motor while continuing to drive the, in substantial synchronism with the timing of the drive stop of the compressor motor, and a speed command correcting means for correcting the velocity command value of the fan motor, wherein In the refrigeration cycle apparatus provided with the secondary side voltage detecting means for detecting the secondary side voltage of the converter circuit, the speed command correcting means is detected by the secondary side voltage detecting means immediately before stopping the driving of the compressor motor. The correction value is determined based on the voltage change width calculated based on the secondary side voltage and the secondary side voltage detected in advance while the compressor motor is stopped .

  ADVANTAGE OF THE INVENTION According to this invention, the rapid increase of the rotation speed of the fan motor resulting from the rapid increase of the secondary side voltage accompanying a compressor stop can be suppressed, and generation | occurrence | production of noise can be prevented.

The schematic block diagram of the air conditioner of one Embodiment of this invention The flowchart which shows the action | operation at the time of the defrost driving | operation of the same embodiment Time chart showing operation of the same embodiment

Next, an air conditioner in which the refrigeration cycle apparatus of the present invention is applied to an air conditioner composed of an indoor unit and an outdoor unit will be described with reference to the drawings.
1 is a compressor that compresses and discharges refrigerant to high pressure, 2 is a four-way valve that switches between heating and cooling by switching the flow direction of the high-temperature and high-pressure refrigerant from the compressor 1, and 3 is a fin that is provided in the indoor unit and exchanges heat with indoor air A tube-type indoor heat exchanger, 4 is a decompression means for decompressing high-pressure refrigerant such as an electronic expansion valve, 5 is a fin-tube outdoor heat exchanger that exchanges heat with outdoor air, 6 is a compressor 1, and a four-way valve 2 The refrigerant pipe which connects the indoor heat exchanger 3, the decompression means 4, and the outdoor heat exchanger 5 in an annular shape constitutes a refrigeration cycle.

  Here, the indoor heat exchanger 3 acts as a radiator that radiates the heat of the high-pressure refrigerant during heating, acts as an evaporator that evaporates the low-pressure refrigerant during cooling, and the outdoor heat exchanger 5 is a refrigerant that is fixed during heating. It acts as an evaporator that evaporates the water and acts as a radiator that radiates the heat of the high-pressure refrigerant during cooling.

  7 is an indoor fan that is provided in the indoor unit and blows indoor air to the indoor heat exchanger 3, 8 is an outdoor fan that blows outdoor air to the outdoor heat exchanger 5, and 9 is a refrigerant discharged from the compressor 1. A discharge temperature sensor 10 for detecting the temperature, a suction temperature sensor 10 for detecting the temperature of the refrigerant sucked into the compressor 1, and an outdoor heat exchange temperature sensor 11 for detecting the temperature of the outdoor heat exchanger 5.

  12 is a compressor motor comprising a three-phase DC brushless motor for driving the compressor 1, 13 is a fan motor comprising a DC brushless motor for driving the outdoor fan 8, and 14 is an FM rotational speed detection means for detecting the rotational speed of the fan motor 13. It is.

  Reference numeral 15 denotes a drive power supply circuit for the compressor motor 12 and the fan motor 13, which converts alternating current from the alternating current power supply 16 into direct current by a converter circuit 19 composed of a diode bridge 17 and a capacitor 18, 12, and the fan motor 13 is driven via a branch circuit 21 branched from the converter circuit 19 and the inverter circuit 20. Reference numeral 22 denotes a secondary voltage for measuring the secondary side voltage of the drive power supply circuit 15. Secondary voltage detection means.

  Reference numeral 23 denotes a discharge temperature sensor 9, an intake temperature sensor 10, an outdoor heat exchanger temperature sensor 11, FM rotation speed detection means 14, and detection values of the secondary side voltage detection means 22. In addition to controlling, the inverter circuit 20 is controlled so as to drive the compressor motor 12 at a desired rotational speed, and the fan motor 13 is referred to the rotational speed detected by the FM rotational speed detecting means 14 so that the fan motor 13 has a desired rotational speed. A control means for varying the speed command value commanded to the motor 13, which stores a program for controlling the operation of the air conditioner in advance and has a calculation, comparison, storage function, and timing function. is there.

  Here, the speed command value of the fan motor 13 is a duty ratio with respect to the voltage applied to the fan motor 13 from the secondary side of the converter circuit 19, and is applied to the fan motor 13 by varying this duty ratio. The rotational voltage can be controlled by varying the drive voltage.

  24 is provided as a function of the control means 23, and when the drive of the compressor motor 12 is stopped while continuing to drive the fan motor 13, the fan motor 13 is substantially synchronized with the drive stop timing of the compressor motor 12. The speed command correcting means 24 corrects the speed command value. The speed command correcting means 24 is a voltage detected by the secondary side voltage detecting means 22 converted into direct current by the converter circuit 19 when the compressor motor 12 is stopped. The value V1 is stored in advance.

  Here, the indoor side heat exchanger 3 and the indoor blower fan 7 are provided in the indoor unit, and other configurations are provided in the outdoor unit, and the indoor unit and the outdoor unit constitute a part of the refrigerant pipe 6. The refrigerant is connected to be circulated through the connecting pipe.

  Next, the operation when the outdoor heat exchanger 5 acting as an evaporator is frosted during the heating operation as an example of stopping the driving of the compressor motor 12 while continuing the driving of the fan motor 13 is shown in FIG. This will be described based on the flowchart of FIG.

  When the control means 23 detects that the outdoor heat exchanger 5 is in a frosted state based on the detected temperatures of the outdoor heat exchange temperature sensor 11 and the suction temperature sensor 10 (Yes in step S1), the secondary side voltage detection is performed. The means 22 detects the secondary voltage V2 before the compressor motor 12 stops (step S2), and the speed command correction means 24 calculates a correction value for the speed command value of the fan motor 13 when the compressor motor 12 is stopped (step S2). S3).

Here, the speed command correction means 24 stores the secondary side voltage value V1 stored when the compressor motor 12 is stopped in advance and the secondary side voltage V2 detected at step S2 before the compressor motor 12 stops. From the above, the correction value α of the speed command value of the fan motor 13 is calculated based on Equation 1.
α = (V2−V1) × β (Expression 1)
Here, β is a coefficient for converting the voltage change width into a correction value of the speed command value.

  Then, the control means 23 stops the drive of the compressor motor 12 (step S4), and then adds the correction value α calculated in step S3 to the speed command value to the fan motor 13 substantially in synchronization with the drive stop timing. Then, it is corrected and commanded to the fan motor 13 (step S5).

  At this time, as shown in the time chart of FIG. 3, the secondary side voltage rapidly rises at the moment when the compressor motor 12 is stopped. Here, when the fan motor 13 is simply controlled by the rotation speed feedback as in the conventional case, the drive voltage of the fan motor 13 rapidly increases, and as shown by the dotted line, the rotation speed of the fan motor 13 rapidly increases, and thereafter However, as shown in the present invention, the speed command correction means 24 uses the secondary-side voltage V2 before the compressor motor 12 stops in synchronism with the drive stop timing of the compressor motor 12, as in the present invention. By driving the fan motor 13 with the speed command value corrected with the correction value α corresponding to the voltage change width of the secondary side voltage V1 when the compressor motor 12 is previously stopped, the compressor motor 12 is stopped. Since the drive voltage of the fan motor 13 can be maintained at an appropriate value almost in synchronism, fluctuations in the rotational speed can be suppressed as shown by the thick line.

  Here, the “substantially synchronized timing” is not limited to exactly the same timing, but may be immediately before or after the compressor motor 12 is stopped. The fan is caused by a change in the secondary side voltage accompanying the stop of the compressor motor 12. If the timing at which the fluctuation of the rotational speed of the motor 13 can be suppressed is effective.

  Then, the control means 23 determines whether a certain time has elapsed since the compressor motor 12 was stopped. If the certain time has elapsed (Yes in step S6), the control means 23 switches the four-way valve 2 to the cooling side (step S7). ), The compressor motor 12 is started (step S8). Then, the high-temperature refrigerant discharged from the compressor 1 flows into the frosted outdoor heat exchanger 5 and melts frost attached to the fins of the outdoor heat exchanger 5 by the heat of the high-temperature refrigerant.

  When the outdoor heat exchanger temperature sensor 11 detects that the defrosting is completed (step S9), the compressor motor 12 is stopped (step S10), the four-way valve 2 is returned to the heating side (step S11), and the compressor motor 12 Is activated (step S12), the fan motor 13 is activated (step S13), and the defrosting operation is terminated.

  Here, since the four-way valve 2 is switched after the compressor motor 12 is reliably stopped, it is possible to prevent a sudden load fluctuation of the compressor 1 and realize stable control.

  Thus, in the case where the compressor motor 12 and the fan motor 13 are connected to the secondary side of the converter circuit 19 via the inverter circuit 20, the compressor motor 12 is stopped while the drive of the fan motor 13 is continued. Even if there is a sudden change in the voltage on the secondary side, the rapid increase in the rotational speed of the fan motor 13 can be suppressed, and the generation of noise can be prevented. Further, since a converter circuit dedicated to the fan motor 13 is not required, there is an advantage that it can be configured at low cost.

  In particular, when the present invention is applied during the defrosting operation, it is possible to suppress the generation of noise due to the rapid increase in the rotational speed of the fan motor 13 every time the defrosting operation frequently occurs in winter, and to further exhibit the effect. It is.

  In addition, this invention is not limited to said embodiment, It can modify | change within the range which does not change the summary of invention, It is not restricted only to an air conditioner, A heat pump type hot water heating apparatus and a heat pump type hot water heater In addition to the operation during the defrosting operation, it is applicable to the case where the compressor is stopped while continuing to drive the blower fan, such as the operation during an emergency stop of the compressor motor 12. It is possible.

1 Compressor 3 Indoor heat exchanger (heat radiator)
4 Pressure reducing means 5 Outdoor heat exchanger (evaporator)
6 Refrigerant piping 8 Outdoor fan 12 Compressor motor 13 Fan motor 16 AC power supply 19 Converter circuit 20 Inverter circuit 22 Secondary voltage detection means 23 Control means 24 Speed command correction means

Claims (1)

A refrigeration cycle in which a compressor that compresses refrigerant to high pressure, a radiator that dissipates heat from the high-pressure refrigerant, decompression means that decompresses and expands the refrigerant from the radiator, and an evaporator that evaporates the low-pressure refrigerant are connected in an annular manner by refrigerant piping. A fan that blows air to the evaporator, a converter circuit that converts AC power into DC, a compressor motor that is connected to the secondary side of the converter circuit via an inverter circuit and drives the compressor, and the converter The inverter circuit is connected to the secondary side of the circuit and drives the blower fan and the compressor motor to drive the compressor motor at a desired rotational speed, and the fan motor has a desired rotational speed. Control means for varying the speed command value commanded to the fan motor, and the front while continuing to drive the fan motor When stopping the driving of the compressor motor, said substantially synchronized with the timing of the drive stop of the compressor motor, and a speed command correcting means for correcting the velocity command value of the fan motor, the secondary side of the converter circuit In the refrigeration cycle apparatus provided with the secondary side voltage detecting means for detecting the voltage, the speed command correcting means detects in advance the secondary side voltage detected by the secondary side voltage detecting means immediately before stopping the driving of the compressor motor. A refrigeration cycle apparatus characterized in that a correction value is determined on the basis of a voltage change width calculated based on the secondary side voltage when the drive of the compressor motor is stopped .

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