JP2003035289A - Refrigeration unit and compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reliable refrigeration unit and compressor having high efficiency with a minimized power consumption and drivable by a commercial power source. SOLUTION: This refrigeration unit comprises the compressor 1 driven by an electric motor, a condenser 3 and an evaporator 7. A refrigerant gas is compressed in a compression chamber formed of a fixed scroll 60 and a rotating scroll 57, and the compressed refrigerant gas is passed through the electric motor and a compression vessel provided on the lower part of the electric motor and having an oil basin part 66 arranged therein, and discharged out of the compressor. The electric motor comprises a winding wound on the iron core of a rotator 52 to function as an induction electric motor and a permanent magnet magnetized on the iron core of the rotator 52 to function as a synchronous electric motor, and it is driven as the induction electric motor in starting and as the synchronous electric motor in steady operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner, an outdoor unit, and a refrigerating apparatus that use a vapor compression refrigeration cycle, and in particular, enables an electric motor mounted in the compressor to be driven by a commercial power source. It is suitable for a wide range of applications, including high-priced products, as well as for promoting common use and facilitating model development.

[0002]

2. Description of the Related Art As a refrigerant compressor used in an air conditioner and an outdoor unit using a vapor compression refrigeration cycle, and a refrigerating apparatus, a constant speed compressor driven at a substantially constant rotation speed, and its rotation speed are controlled. There is an inverter type compressor,
An induction motor provided with a squirrel cage conductor (winding) is often used because it can be easily driven by an AC voltage of a commercial frequency. Further, from the viewpoint of high efficiency, it is also possible to adopt a DC motor having a rotor having a permanent magnet in the rotor core and an armature having three-phase windings in the armature core, for example, JP-A-5-211796. It is known as described in the publication.

Further, as an industrial motor, an embedded magnet synchronous motor has been proposed as a motor capable of being driven by a commercial power source with high efficiency in response to the demand for energy saving. For example, Hirano et al.
Name: New high rate motor and application: Technical report Yasukawa, Volume 62, No.
4, 1998, Volume 241.

[0004]

In the prior art described above, the one disclosed in Japanese Patent Laid-Open No. 5-211796 is good in terms of high efficiency, but the frequency can be varied to the power source for starting. The use of an inverter is inevitable, the power supply circuit and the like are complicated, and when viewed as a system having a refrigeration cycle, depending on the application, it may be unnecessarily complicated and expensive.

Further, in order to employ the embedded magnet synchronous motor according to the above-mentioned prior art in an air conditioner, an outdoor unit and a refrigerating apparatus in which a refrigerating cycle is used, for example, the rotation speed of the electric motor is also required in the refrigerating cycle. The amount of refrigerant discharged and the efficiency of the refrigeration cycle must be taken into consideration, and the volume of the compression chamber of the compressor, the size of the entire compressor, and the size of the outdoor unit equipped with the compressor must not be increased. I have to.

Further, when the refrigeration cycle is started, if the differential pressure between the discharge side and the suction side of the compressor is large, even the embedded magnet synchronous motor cannot be started, and its reliability is insufficient. There is a risk of becoming.

Further, when an overload occurs during steady operation of the refrigeration cycle, that is, during synchronous operation, the rotor of the embedded magnet synchronous motor is greatly stalled, or the winding temperature of the motor rises, in the worst case, The insulation material of the winding is deteriorated, or the insulation of the winding is broken, so that the reliability of the device is significantly impaired. Further, it is necessary to minimize the influence on the deterioration of the refrigerant and the lubricating oil circulating in the refrigeration cycle of the permanent magnet of the embedded magnet synchronous motor.

An object of the present invention is to provide a highly reliable refrigerating apparatus and compressor which consumes less power and has high efficiency, and which can be driven by a commercial power source.

Further, the object of the present invention is to achieve a high efficiency, but the volume of the compression chamber of the compressor, the size of the entire compressor, an outdoor unit in which the compressor is mounted, a refrigeration system (including air). The goal is to reduce the size of the harmony machine. In addition,
The present invention achieves at least one of the above objects and objectives.

[0010]

In order to solve the above problems, the present invention relates to a refrigerating apparatus provided with a compressor driven by an electric motor, a condenser, and an evaporator, wherein the refrigerant gas is composed of a fixed scroll and an orbiting scroll. Compressed in the compression chamber, the compressed refrigerant gas passes through the inside of the compression container in which the electric motor and the oil sump portion provided in the lower part of the electric motor are disposed, and is discharged to the outside of the compressor. ,
A winding wound around the iron core of the rotor so as to function as an induction motor, and a permanent magnet that is also magnetized around the iron core of the rotor so as to function as a synchronous motor are provided. As a result, it is driven as a synchronous motor during steady operation.

As a result, the compressor, the outdoor unit, the refrigerating device, etc. can be made small and compact, which is advantageous for improving the efficiency of the refrigerating cycle and reducing the noise. In particular, the efficiency of the refrigeration cycle is reduced because the electric motor is in a synchronous state during steady operation, power for slipping is not required, and the rotation speed of the compressor does not change even when the load increases due to changes in the outside air temperature. The fact that the refrigeration cycle itself can be stabilized even if there is a load change on the refrigeration cycle can be further improved.

Further, the compression mechanism can be shared with a variable speed air conditioner using an inverter, and the model can be easily developed and the cost can be reduced. Further, at the time of starting, a large amount of the refrigerant liquid returns to the compressor to reduce the oil viscosity of the lubricating oil, or at the time of starting the heating operation, the start-up becomes poor, but the refrigerant gas is allowed to pass through the electric motor chamber, Since it is driven in a non-synchronized state with slippage from the commercial power supply to the start of synchronization, the heat generated by the electric motor heats the refrigerant and lubricating oil, preventing damage to the compressor bearings and increasing the heating capacity. can do.

Further, according to the present invention, the refrigerant gas is compressed in a compression chamber formed by meshing the spiral wraps, and the compressed refrigerant gas is provided with an electric motor and an oil sump portion provided under the electric motor. After passing through the inside of the compression container and discharged to the outside of the compressor, the electric motor is wound around the iron core of the rotor to function as an induction motor, and the electric motor of the rotor also functions as a synchronous motor. And a permanent magnet magnetized at the same time, and is driven as an induction motor at the time of starting and as a synchronous motor at the time of steady operation.

As a result, at least in the heating operation,
Since the refrigeration cycle is started as an induction motor, the heat generation of the electric motor heats the refrigerant and the lubricating oil to prevent the viscosity from decreasing, the bearing of the compressor is prevented from being damaged, and the heating capacity can be increased. In spite of this, thereafter, the electric motor is brought into a synchronous state and the rotation speed of the compressor does not change, so that the compression efficiency can be prevented from lowering even if the outside air temperature changes and the load increases.

Further, in the above, a bypass circuit for bypassing the discharge side and the suction side of the compressor is provided,
It is desirable to bypass the discharge side and the suction side before starting. Further, in the above, it is desirable to use a neodymium or samarium-cobalt magnet as the permanent magnet. Further, in the above, it is desirable that the surface of the permanent magnet is coated or plated.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. In order to improve the efficiency of the air conditioner that uses the vapor compression refrigeration cycle, it is effective to improve the efficiency of the electric motor used for the refrigerant compressor that consumes the most power among the components that form the refrigeration cycle. Conventionally, an induction motor is often used as a refrigerant compressor, but a synchronous motor in which a permanent magnet is embedded in a rotor core is known as a motor having a higher efficiency than that. Since the synchronous motor rotates using the attraction of the rotating magnetic field generated by the permanent magnet embedded in the rotor of the electric motor and the stator, the induction motor does not generate the secondary current flowing in the rotor of the electric motor. The efficiency is high because there is no energy loss. However, when the synchronous motor is used as the electric motor used for the refrigerant compressor, the following matters must be considered. When a synchronous motor is used as the electric motor of the refrigerant compressor and a commercial power source is directly connected to the synchronous motor, the rotating magnetic field generated from the stator of the electric motor has a rotational speed (synchronous speed) corresponding to the power supply frequency (50/60 Hz). Becomes The rotor of the electric motor used in the refrigerant compressor has a large inertial force because it is integrated with the rotating parts of the refrigerant compressor. Therefore, at the time of starting, the rotor cannot follow the rotation speed of the rotating magnetic field generated by the stator, and the refrigeration cycle cannot be started. Therefore, when a constant speed compressor is required, it is preferable to drive on a commercial power source, so that the synchronous motor cannot be used.

1 and 2 show an air conditioner according to an embodiment of the present invention, in which a compressor is a constant speed compressor driven by a commercial power source, and an electric motor used in the compressor is shown. When the rotor core has a synchronous speed or less, a synchronous motor that acts as an induction motor is built in, that is, a permanent magnet magnetized with two poles is embedded in the rotor core. The air conditioner shown in FIG. 1 is configured by sequentially connecting a constant speed compressor 1, a four-way valve 2, an outdoor heat exchanger 3, an outdoor expansion device 5, an indoor expansion device 6, an indoor heat exchanger 7, and an accumulator 9. ing. As a motor used in the constant speed compressor 1, a squirrel cage winding (conductor) is formed in the rotor in the vicinity of the outer circumference of the rotor along the circumferential direction, and a permanent magnet is embedded in the rotor. Then, the rotor operates as an induction motor until the rotation speed of the rotor reaches the synchronous speed, and when the rotation speed of the rotor reaches the synchronous speed, it operates as the synchronous motor. Therefore, it is possible to start without using an inverter, and at the time of operation at synchronous speed, that is, steady operation at a rotation speed (3000r / min, 3600r / min) determined by the power supply frequency (50 / 60Hz) of the commercial power supply. In some cases, secondary current is not generated in the rotor of the electric motor, so that efficiency can be improved.

As the electric motor used in the constant speed compressor 1, a permanent magnet is embedded in the rotor of the electric motor. However, a simple permanent magnet type synchronous motor and a synchronous motor driven near the synchronous speed of the synchronous motor. It may be combined with an induction motor capable of In this case, at the time of starting, first, power is supplied only to the induction motor, and when the rotation speed of the rotor of the motor reaches close to the synchronous speed of the synchronous motor, the power supply to the induction motor is cut off, and at the same time, the electric power is supplied to the synchronous motor. Supply. As a result, the compressor 1 is driven only by the synchronous motor in the steady operation, the operating efficiency of the electric motor and the compressor 1 is increased, and the efficiency of the air conditioner as a whole is significantly improved.

That is, since the synchronous motor does not cause a slip between the stator and the rotor, which is present in an induction motor, the load fluctuation of the rotation speed of the rotor is smaller than that of the induction motor, and if the same load is applied, compression occurs. Since the rotation speed of the machine 1 becomes faster, the amount of refrigerant compressed by the refrigerant compression mechanism portion of the compressor 1 also increases, the refrigerant discharge amount of the compressor 1 increases, and as shown in FIG. Its capacity can be improved in the load range.

In particular, even when the refrigeration cycle is overloaded, the slippage becomes 0 in the synchronous state, and no current flows in the cage conductor. The effect of improving ability is very large. Further, if the compressor 1 is a scroll compressor, the fluctuation of the compression torque is small, and the load fluctuation of the electric motor is small, so that the efficiency can be further improved. Although FIG. 2 shows an example during the cooling operation, the same is true during the heating operation.

Further, since the rotation speed of the rotor of the electric motor is inversely proportional to the number of poles of the electric motor, by setting the number of poles of the electric motor to the minimum of two, the rotation speed of the rotor of the electric motor becomes faster,
The refrigerant discharge amount from the compressor 1 increases. Therefore, the volume of the compression chamber of the compressor 1 can be reduced, and the size of the compressor 1 and the outdoor unit 20 in which the compressor 1 is mounted can be reduced. Further, the compression mechanism portion or other components required for the refrigeration cycle can be shared with a variable speed air conditioner using an inverter, and the model development can be facilitated at a low cost. Details of the compressor 1 and the rotor 52 will be described with reference to FIGS. The compressor mechanism portion is formed by meshing a spiral wrap 63 which is upright on the end plate 61 of the fixed scroll 60 and a spiral wrap 68 which is upright on the end plate 58 of the orbiting scroll 57 to form the orbiting scroll 57 on the crankshaft. A compression operation is performed by making a turning motion by 55. Of the compression chambers 59 (59a, 59b ...) Formed by the fixed scroll 60 and the orbiting scroll 57, the compression chamber located on the outermost side is the scrolls 6 along with the orbiting motion.
Moving towards the center of 0, 57, the volume gradually decreases. Both compression chambers 59a and 59b have scrolls 60 and 57.
When reaching the vicinity of the center, the compressed refrigerant gas in both compression chambers is discharged from the discharge port 62 communicating with the compression chambers. The discharged refrigerant gas is used for the fixed scroll 60 and the frame 5.
6 passes through a gas passage provided in 6 to reach the inside of the compression container under the frame 56, and is discharged to the outside of the compressor from a discharge pipe 64 provided on the side wall of the compression container.

Further, an electric motor is enclosed in the pressure vessel (electric motor chamber), and the orbiting scroll 57 is driven by the electric motor to perform compression operation. At the bottom of the motor, an oil sump 66
Is provided, and the lubricating oil therein passes through an oil hole 65 provided in the crankshaft 55 due to a pressure difference generated by the rotary motion to lubricate a sliding portion between the orbiting scroll 57 and the crankshaft 55, a sliding bearing, and the like. To do.

The electric motor is an embedded magnet type synchronous electric motor composed of a stator 51 and a rotor 52, and the stator 51 has a stator core 53 and an armature winding (conductor) wound around it. Then, the rotor 52 is provided with the rotor core 52 in which the permanent magnet 71 is embedded and which has the inter-magnet slit 73.
FIG. 7 shows a detailed structure of the rotor 52. The permanent magnet 71 is magnetized to have two poles, and a conductor is embedded near the outer periphery of the rotor 52 to form a cage-shaped conductor (winding) 72. .

Next, another embodiment will be described with reference to FIG. When starting the refrigeration cycle, if the pressure difference between the discharge side and the suction side of the compressor 1 is large, the start becomes impossible or its reliability becomes insufficient. Therefore, it is necessary to secure a sufficient starting torque of the electric motor. There is. Therefore, even if the refrigeration cycle is started as an induction motor and then operated as a synchronous motor, the action as an induction motor is increased in order to increase the starting torque of the motor, that is, the amount of the cage conductor of the rotor is increased. Alternatively, the wire diameter must be increased in order to increase the current, which may increase the size of the compressor 1. In order to make it compact, it becomes structurally difficult to embed the permanent magnet in the iron core of the rotor provided with the cage conductor. Further, it takes several minutes after the compressor 1 is stopped to balance the pressure in the refrigeration cycle.

Therefore, the discharge side and the suction side of the compressor 1 are connected by a bypass pipe, an opening / closing valve 10 for opening and closing the bypass circuit is provided, and the opening / closing valve 10 is opened before starting, whereby the discharge pressure and the suction pressure are increased. Since it is possible to reduce the pressure difference with the compressor 1, the compressor 1 can be easily started, and the amount of the cage conductor can be reduced. Therefore, it is easy to install a permanent magnet on the rotor 52, which is suitable for compactness and is reliable. It is possible to secure the sex. Furthermore, when the torque applied to the rotor 52 of the electric motor of the compressor 1 is increased during the operation of the compressor 1, that is, the discharge pressure is increased, the rotor of the electric motor may stall. Therefore, the discharge pressure value Pdset at which the rotor 52 of the electric motor does not stall is set, the discharge pressure is measured by the discharge pressure detection device 14, and when the discharge pressure rises to Pdset, the on-off valve 10 is opened to lower the discharge pressure. As a result, it is possible to prevent the abnormality of the refrigeration cycle due to the stall of the electric motor. Further, if the compressor is a scroll compressor, the fluctuation of the compression torque is small, so that the abnormality of the refrigeration cycle can be further prevented, the reliability can be improved, and the noise reduction can be achieved.

The pressure detecting device 14 has a set pressure Pds.
The pressure switch may be set so that the switch of the electric circuit opens (or closes) when it becomes et.

Next, another embodiment of the present invention will be described with reference to FIG. In this air conditioner, a liquid receiver 11 is provided between the outdoor heat exchanger 3 and the indoor heat exchanger 7 (the outdoor heat exchanger 3 and the indoor expansion device 6), and the main pipe and the inside of the liquid receiver 11 are provided. A bypass pipe that bypasses the gas refrigerant in the liquid receiver 11 and a shutoff valve 10a, 10b that opens and closes the bypass circuit are provided on the downstream side with respect to the flow direction of the refrigerant inlet / outlet pipe or the main pipe that connects the There is.

During the cooling operation, by opening the on-off valve 10b, the gas refrigerant in the liquid receiver 11 can be led out, and the refrigerant dryness at the inlet and outlet of the liquid receiver 11 increases,
Since the degree of dryness of the refrigerant at the outlet of the outdoor heat exchanger 3 acting as a condenser is increased, the refrigerant can be effectively used as a condenser, so that the condensation pressure can be kept low and the discharge pressure can be lowered. On-off valve 10a during heating
By opening the, the same effect as when cooling can be obtained. Utilizing this, the discharge pressure Pdset at which the rotor 52 of the electric motor used for the compressor 1 does not stall is set, the discharge pressure is detected by the discharge pressure detection device 14, and when it reaches Pdset, the on-off valve 10b is turned on during cooling. On-off valve 10a during heating
The discharge pressure can be lowered by opening the valve, and abnormalities in the refrigeration cycle can be prevented.

Another embodiment will be described with reference to FIG. As the compressor 1, one variable speed compressor 1a and a constant speed compressor 1b driven by one or more commercial power sources are mounted, and a check valve 13 is provided on the discharge side of the constant speed compressor 1b. Further, an oil separator 12 is provided. The indoor unit is 21a,
21b, a plurality of them are provided, and the load greatly varies depending on the usage state of each. When the load on the indoor unit side is small, it is not necessary to drive all the compressors 1a and 1b,
The capacity control operation is performed by driving only the variable speed compressor 1a. When the load on the indoor unit side increases when only the variable speed compressor 1a is driven and the capacity cannot be secured only by the variable speed compressor 1a, the constant speed compressor 1a
drive b. At that time, since the variable speed compressor 1a has already been driven, the differential pressure between the discharge side pressure and the suction side pressure becomes large when viewed as the constant speed compressor 1b. Therefore,
The check valve 13 is installed on the discharge side of the constant speed compressor 1b to reduce the differential pressure between the discharge side pressure and the suction side pressure of the constant speed compressor 1b even while the variable speed compressor 1a is being driven. do it,
The start-up with commercial power can be facilitated. Therefore,
Even if a large capacity is required like a multi air conditioner, the capacity variable range can be increased without adding an inverter power supply.
In addition, fine control can be realized.

In the above, as the compressor 1, as a permanent magnet embedded in the iron core of the rotor 52 of the electric motor, neodymium, iron, boron magnet, or samarium.
Using a cobalt magnet reduces the size of the permanent magnet,
And the number can be reduced. Therefore, the rotor 52
It is structurally easy to provide the cage conductor and the permanent magnet in the iron core, and the compressor 1 can be downsized. Since the efficiency is also improved, the size of the outdoor unit (outdoor unit) 20 in which the compressor 1 is mounted can be reduced.

Furthermore, when neodymium, iron, boron magnets or samarium-cobalt magnets are used as the permanent magnets of the electric motor, the refrigerant and the lubricating oil come into contact with the permanent magnets, and neodymium or samarium which is a constituent material of the permanent magnets. Rare earth element of acts as a strong catalyst, deteriorates the lubricating oil,
The deteriorated product is deposited as sludge in the low temperature portion of the refrigeration cycle and blocks the capillary, which impedes the flow of the refrigerant and causes the temperature of the refrigerant compressor to rise abnormally. However, by coating the surface of the permanent magnet with nickel plating or aluminum plating, the refrigerant and the lubricating oil in the compressor 1 do not come into direct contact with the permanent magnet, so that the deterioration of the lubricating oil is suppressed. Therefore, the reliability can be improved.

[0032]

As described above, according to the present invention,
It is possible to provide a highly reliable refrigeration system and compressor that consumes less power, has higher efficiency, and can be driven by a commercial power source. Further, despite the high efficiency, it is possible to reduce the volume of the compression chamber of the compressor, the size of the entire compressor, and the outdoor unit and the refrigeration apparatus in which the compressor is mounted.

[Brief description of drawings]

FIG. 1 is a system diagram of a refrigeration cycle according to an embodiment of the present invention.

FIG. 2 is a graph showing the relationship between the outside air temperature and the cooling capacity of the air conditioner according to the embodiment of the present invention.

FIG. 3 is a system diagram of a refrigeration cycle according to still another embodiment of the present invention.

FIG. 4 is a system diagram of a refrigeration cycle according to still another embodiment of the present invention.

FIG. 5 is a system diagram of a refrigeration cycle according to still another embodiment of the present invention.

FIG. 6 is a side sectional view of a compressor according to an embodiment of the present invention.

FIG. 7 is a sectional view of a rotor of an electric motor according to an embodiment of the present invention.

[Explanation of symbols]

1, 1b ... Constant speed compressor, 1a ... Inverter compressor, 2
... four-way valve, 3 ... outdoor heat exchanger, 4 ... outdoor blower, 5,
5a ... outdoor expansion device, 6, 6a, 6b ... indoor expansion device,
7, 7a, 7b ... Indoor heat exchanger, 8, 8a, 8b ... Indoor blower, 9 ... Accumulator, 10, 10a, 10b
... electromagnetic on-off valve, 11 ... liquid receiver, 12 ... oil separator 13 ...
Check valve, 14 ... Discharge pressure detection device, 20 ... Outdoor unit, 21, 21a, 21b ... Indoor unit.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H02K 1/27 H02K 1/27 501K 21/14 21/14 M (72) Inventor Akira Saruta Shimizu City, Shizuoka Prefecture 390 Muramatsu Hitachi Shimizu Co., Ltd. Production Headquarters (72) Inventor Kazuki Urata 390 Muramatsu, Shimizu City, Shizuoka Prefecture F Term in Hitachi Shimizu Co., Ltd. Shimizu Production Headquarters (reference) 3H029 AA02 AA14 AB03 BB42 CC07 CC23 CC24 CC25 CC25 CC27 CC38 3H039 AA03 AA06 AA12 BB28 CC26 CC28 CC29 CC32 CC35 5H621 AA01 GA01 GA05 HH10 5H622 AA01 CA02 CA12 CB03 DD02 QA08

Claims (5)

[Claims] 1. A refrigerating apparatus including a compressor driven by an electric motor, a condenser, and an evaporator, wherein refrigerant gas is compressed in a compression chamber constituted by a fixed scroll and an orbiting scroll, and the compressed refrigerant gas is The electric motor and the oil reservoir provided at the lower part of the electric motor pass through the inside of the compression container and are discharged to the outside of the compressor.
A winding wound around the iron core of the rotor so as to function as an induction motor, and a permanent magnet that is also magnetized around the iron core of the rotor so as to function as a synchronous motor are provided. As a refrigerating device, it is driven as a synchronous motor during steady operation. 2. A compression container in which a refrigerant gas is compressed in a compression chamber formed by meshing spiral wraps, and the compressed refrigerant gas is provided with the electric motor and an oil sump portion provided under the electric motor. The electric motor passes through the inside and is discharged to the outside of the compressor, and the electric motor has windings wound around the iron core of the rotor so as to function as an induction motor, and also functions as a synchronous electric motor around the iron core of the rotor. And a permanent magnet that is magnetized at the same time, and is driven as an induction motor at the time of starting and as a synchronous motor at the time of steady operation. 3. The refrigeration system according to claim 1, wherein a bypass circuit for bypassing a discharge side and a suction side of the compressor is provided, and the discharge side and the suction side are bypassed before starting. apparatus. 4. The compressor according to claim 2, wherein a neodymium or samarium-cobalt magnet is used as the permanent magnet. 5. The compressor according to claim 2, wherein the surface of the permanent magnet is coated or plated.