JP2009204173A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To significantly improve a maximum heating capacity by keeping a current value of an invertor circuit and an operating current value of an outdoor unit in a high load operation within allowable ranges, and maximizing a rotational frequency of a motor in a low load operation. <P>SOLUTION: In this air conditioner comprising a compressor 1 driven by a brushless DC motor of variable frequency, the invertor circuit for driving the motor, and a control circuit for controlling the invertor circuit, a current phase of the motor is controlled on the basis of the rotational frequency of the motor and the operating current of the motor. By controlling the current phase of the motor on the basis of the rotational frequency of the brushless DC motor and the operating current of the motor, the current value of the invertor circuit in the high load operation is kept within the allowable range, and the rotational frequency of the motor is increased to the greatest extent in the low-load operation, thus the maximum heating capacity is significantly improved. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an air conditioner that improves the maximum heating capacity.

Conventionally, as an air conditioner for improving the maximum heating capacity, the magnetic flux generated by the motor coil in the motor coil by shifting the phase of the current of the brushless DC motor for driving the compressor in the advance direction as shown in FIG. The maximum heating speed is increased to increase the maximum heating capacity (for example, see Patent Document 1).
JP-A-5-272823

  However, in the above conventional configuration, the degree of advancement of the motor current phase is not changed even when the operating condition changes, so that the current value of the inverter circuit and the operating current value of the outdoor unit are within an allowable range during high current operation at the maximum load. Therefore, it has been necessary to suppress the advance width of the motor current phase so as to be within the range, and as a result, the increase in the maximum heating capacity is reduced.

  The present invention solves the above-described conventional problems, and keeps the current value of the inverter circuit and the operation current value of the outdoor unit in a high load operation within an allowable range, and increases the rotation speed of the motor to the maximum in a low load operation. Thus, an object of the present invention is to provide an air conditioner that can greatly improve the maximum heating capacity.

  In order to solve the above-described conventional problems, an air conditioner according to the present invention controls the current phase of a motor based on the rotational speed of a brushless DC motor and the operating current of the motor, so The maximum heating capacity is greatly improved by keeping the current value within an allowable range and by increasing the rotational speed of the motor to the maximum during low load operation.

  In addition, the air conditioner of the present invention controls the motor current phase based on the rotation speed of the brushless DC motor and the operating current of the air conditioner, thereby keeping the operating current value of the outdoor unit in a high load operation within an allowable range. In the low load operation, the maximum heating capacity is greatly improved by increasing the rotational speed of the motor to the maximum.

  In addition, the air conditioner of the present invention maximizes the rotational speed of the motor by advancing the current phase of the motor with respect to the voltage when the rotational speed of the brushless DC motor has not reached the predetermined target rotational speed. Increase the maximum heating capacity significantly.

  The air conditioner of the present invention can control the current phase according to the load by changing the current phase of the motor during high load operation and low load operation.

  A first aspect of the present invention is an outdoor unit including a compressor driven by a brushless DC motor having a variable rotation speed, an inverter circuit that drives the motor, and a control circuit that controls the inverter circuit. By controlling the current phase of the motor based on the operating current of the motor, the current phase of the motor during high load operation and low load operation can be changed, and the current phase can be controlled according to the load.

  According to a second aspect of the present invention, there is provided an outdoor unit including a compressor driven by a brushless DC motor having a variable rotation speed, an inverter circuit that drives the motor, and a control circuit that controls the inverter circuit. By controlling the current phase of the motor based on the operating current of the outdoor unit, the current phase of the motor during high load operation and low load operation can be changed, and the current phase can be controlled according to the load.

  According to the third aspect of the invention, in particular, when the rotational speed of the motor of the first and second aspects of the invention does not reach a predetermined target rotational speed, the current phase of the motor is advanced with respect to the voltage, so that only the necessary amount is obtained. The current phase can be advanced.

  According to a fourth aspect of the present invention, particularly when the current value of the brushless DC motor of the first aspect exceeds a predetermined value, the motor current is always controlled by controlling the maximum value of the current phase of the motor to a predetermined value or less. Can be within the allowable range.

  In the fifth aspect of the invention, particularly when the operating current of the outdoor unit of the second aspect of the invention exceeds a predetermined value, the operating current of the outdoor unit is always controlled by controlling the maximum value of the current phase of the motor to a predetermined value or less. It can be within the allowable range.

  In a sixth aspect of the invention, particularly in the first to fifth aspects of the invention, the current phase of the motor is a rotational phase of the brushless DC motor or a phase with respect to the induced voltage.

  In a seventh aspect of the invention, particularly in the first to fifth aspects of the invention, the current phase of the motor is a phase with respect to the voltage applied to the brushless DC motor.

  The eighth invention is an air conditioner comprising at least two machine blocks that are spatially separated, particularly in the second or fifth invention, wherein an inverter circuit is provided as an operating current of the air conditioner. The operation current of the machine block on the other side or the input current of the inverter circuit is used.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited by this embodiment.

(Embodiment 1)
FIG. 1 shows a configuration of an air conditioner according to a first embodiment of the present invention.

  The compressor 1 is a variable capacity compressor driven by a brushless DC motor having a variable rotation speed, and the rotation speed is controlled by a control device 2 having a control circuit including an inverter circuit. The control device 2 detects the operating current values of the compressor 1 and the outdoor unit 3. The refrigerant discharged from the compressor 1 passes through the four-way valve 4 and is liquefied and condensed in the indoor heat exchanger 6 of the indoor unit 5 during heating, is decompressed and expanded by the decompression expansion valve 7, and absorbs heat by the outdoor heat exchanger 8. It is sucked into the compressor 1 through the four-way valve 2.

  About the air conditioner comprised as mentioned above, the operation | movement and an effect | action are demonstrated below using the flowchart of FIG.

  First, in step 1, the motor rotation speed NHz and motor current Im, and the outdoor unit 3 operating current Ig are detected, and in step 2, the characteristic of the phase advance width β with respect to NHz previously recorded in the microcomputer shown in FIG. Based on the above, the current phase β of the motor with respect to the motor voltage is determined from the characteristic of β0 when Im <predetermined value Imh and Ig <Igh, and otherwise the characteristic of β1.

  In STEP 3, when NHz has not reached the target rotational speed SHz, the process proceeds to β in STEP 4 and the width 1 is added to increase the advance width. If SHz has been reached, proceed directly to STEP5.

In STEP5, the motor current Im is compared with the predetermined current Ims, and if it exceeds Ims, β is set in STEP6 to a phase βs in which Im does not exceed the allowable current even at the maximum load. If it does not exceed Ims, proceed to STEP 7 as it is.
In STEP 7, the outdoor unit current Ig is compared with the predetermined current Igs. If it exceeds Igs, β is set to STEP βs in which Ig does not exceed the allowable current even in the maximum load in STEP 8, and the process proceeds to return to complete one cycle of control. . If the value does not exceed Img, the control cycle that proceeds to return is repeated.

  In this way, by controlling the motor current phase with the motor speed, motor operating current, and outdoor unit operating current, the current value of the inverter circuit and the operating current value of the outdoor unit during high-load operation are kept within an allowable range. In the low load operation, the maximum heating capacity can be greatly improved by maximizing the phase and maximizing the rotation speed of the motor.

  In the description of the embodiment, the example in which the operating current of the outdoor unit is used has been described. However, since most of the power consumption of the air conditioner is generally a compressor, the input current of the inverter circuit used for driving and the air conditioning The operating current of the entire machine can be substituted. In addition, this type of air conditioner also includes an air conditioner composed of at least two machine blocks that are spatially separated. In such an air conditioner, an inverter circuit is used as the operating current of the air conditioner. It is also possible to use the operating current of the machine block on the side provided with or the input current of the inverter circuit.

  As described above, the air conditioner of the present invention keeps the current value of the inverter circuit in the high load operation and the operation current value of the entire apparatus within the allowable range, and the motor speed is increased by maximizing the phase in the low load operation. Therefore, it can be applied to applications such as a heat pump water heater or a refrigerator that drives a brushless DC motor with an inverter.

The block diagram of the air conditioner in Embodiment 1 of this invention Flow chart of control in the first embodiment The figure which shows the characteristic of the phase advance width with respect to the operating frequency in Embodiment 1 The figure which shows the relationship between the motor voltage V and the electric current i of the conventional air conditioner.

Explanation of symbols

1 Compressor 2 Control device (control circuit)
8 Outdoor heat exchanger (outdoor unit)

Claims (8)

In an air conditioner comprising a compressor driven by a brushless DC motor having a variable rotation speed, an inverter circuit for driving the motor, and a control circuit for controlling the inverter circuit, the rotation speed of the motor and the operating current of the motor And controlling the current phase of the motor on the basis of the air conditioner. In an air conditioner comprising a compressor driven by a brushless DC motor having a variable rotation speed, an inverter circuit for driving the motor, and a control circuit for controlling the inverter circuit, the rotation speed of the motor and the air conditioner of the air conditioner An air conditioner that controls a current phase of the motor based on an operating current. The air conditioner according to claim 1 or 2, wherein when the rotation speed of the brushless DC motor does not reach a predetermined target rotation speed, the current phase of the motor is advanced. The air conditioner according to claim 1, wherein when the current value of the brushless DC motor exceeds a predetermined value, the maximum value of the current phase of the motor is controlled to be a predetermined value or less. The air conditioner according to claim 2, wherein when the operating current of the air conditioner exceeds a predetermined value, the maximum value of the current phase of the motor is controlled to a predetermined value or less. The air conditioner according to any one of claims 1 to 5, wherein the current phase of the motor is a rotational phase of the brushless DC motor or a phase with respect to an induced voltage. The air conditioner according to any one of claims 1 to 5, wherein the current phase of the motor is a phase with respect to a voltage applied to the brushless DC motor. An air conditioner composed of at least two machine blocks that are spatially separated, and the operating current of the machine block on the side provided with the inverter circuit or the input current of the inverter circuit is used as the operating current of the air conditioner. The air conditioner according to claim 2 or 5, wherein the air conditioner is used.