WO2015166580A1

WO2015166580A1 - Compressor, refrigeration cycle device, and method for controlling compressor

Info

Publication number: WO2015166580A1
Application number: PCT/JP2014/062161
Authority: WO
Inventors: 増本　浩二; 裕貴田村
Original assignee: 三菱電機株式会社
Priority date: 2014-05-02
Filing date: 2014-05-02
Publication date: 2015-11-05

Abstract

A compressor according to the present invention is provided with a shell (1), a compression mechanism unit (5) that is disposed in the shell (1) and compresses and discharges an inflowing refrigerant to outside, a motor (3) that has a permanent magnet (3b) and supplies power to the compression mechanism unit (5), and a control device (14) that applies a voltage having a non-conduction interval for detecting an induced voltage of the motor (3) to the motor (3) to control power supplied to the motor (3). The temperature of the magnet is estimated on the basis of the induced voltage detected in the non-conduction interval, whereby the temperature in the compressor can be estimated with high accuracy and high performance and high reliability can be maintained.

Description

Compressor, refrigeration cycle apparatus and compressor control method

The present invention relates to a compressor or the like used in a refrigeration cycle apparatus such as an air conditioner, a refrigeration apparatus, or a refrigeration apparatus.

Conventionally, refrigeration cycle devices such as air conditioners have been required to be improved in consideration of environment, resources, and the like. For example, in order to prevent global warming, a refrigerant having a low GWP (global warming potential) is required. In addition, rare earth magnets used in permanent magnets of permanent magnet motors for the purpose of high efficiency are required to reduce the amount of heavy rare earth metals (especially dysprosium) used in order to save resources and stabilize procurement. It has been. Furthermore, in order to reduce environmental load, it is calculated | required to reduce the usage-amounts, such as an alloy containing lead.

However, if a magnet that does not contain dysprosium is used, the coercivity of the magnet at high temperatures generally deteriorates. In addition, many of the slidable alloys used for compressor bearings contain metals with high environmental impact such as lead. Thus, reducing dysprosium, lead, etc. generally leads to a decrease in the reliability of the compressor.

Here, for example, as a refrigerant, an R32 refrigerant having a GWP of 650 and having no toxicity, strong flammability, or the like is attracting attention. In addition, the magnetic flux density has been increased, and development for realizing a predetermined magnetic flux in a smaller volume has been advanced. The proposal of the compressor carrying the electric motor which employ | adopts such a refrigerant | coolant and a magnet is made | formed (for example, refer patent document 1).

For example, in the case of R32 refrigerant, the discharge temperature of the refrigerant that is compressed and discharged by the compressor is about 20 ° C. higher than that of the conventional refrigerant, which may increase the temperature inside the compressor. Therefore, in order to ensure quality, it is necessary to make improvements such as limiting the driving capability of the compressor and reducing performance.

For example, the compressor described in Patent Document 1 has a structure in which the electric motor is cooled with the compressed refrigerant, and the magnet of the electric motor is likely to be hot. For this reason, a magnet having a high coercive force (for example, a coercive force of 23 kOe (about 1830 A / m or more)) must be employed to increase the thickness of the magnet of the motor, and a heavy rare earth metal (for example, dispro This leads to the use of a magnet containing a large amount of (sium). As a result, the cost and size of the compressor are increased.

Also, since the motor is exposed to a high temperature, Joule loss increases due to an increase in resistance value due to an increase in the temperature of the winding, and the loss of the motor increases. The heat generated by this loss spurs an increase in the discharge temperature of the R32 refrigerant, which is higher than the original, leading to a reduction in efficiency of the refrigeration cycle.

Furthermore, for example, when the inside of the compressor is in a high temperature atmosphere, the bearings are likely to become high temperature. For this reason, in consideration of slidability, a bearing using an expensive alloy must be employed, which increases costs. In some cases, a material having a high environmental load is selected.

JP 2001-115963 A

In order to solve the above problems, a compressor is conventionally provided by attaching a temperature sensor to the outer shell of the compressor (a suction pipe for sucking refrigerant, a discharge pipe for discharging refrigerant, the outside of a closed container close to the temperature of oil, etc.) Estimating the internal temperature has been done. Then, based on the temperature inside the compressor, the drive is limited so that the electric motor, the bearing and the like do not become high temperature.

Here, the temperature inside the compressor by the temperature sensor described above is a temperature obtained by indirectly estimating from the outside. It is also predicted that there will be individual differences in temperature sensors due to temperature detection variations and mounting conditions. For this reason, there is a tendency that the timing for applying the drive restriction with an allowance increases, and there is a possibility that an overprotection situation occurs. For example, there is a possibility of stopping or shifting the compressor without driving the compressor necessary for the operation of the refrigeration cycle apparatus, and the efficiency of the entire refrigeration cycle apparatus is reduced.

The present invention has been made to solve the above-described problems, and an object thereof is to provide a compressor or the like that can maintain high performance and high reliability regardless of the compression target.

A compressor according to the present invention includes a sealed container that is an outer shell, a compression mechanism that is installed in the sealed container, compresses the fluid that has flowed in, and discharges the fluid to the outside, and supplies power to the compression mechanism. And a control device for controlling the power supplied to the motor by applying a voltage provided with a non-energized section for detecting the induced voltage of the motor to the motor.

According to the compressor according to the present invention, since the induced voltage of the motor can be detected by providing a non-energized section in the voltage applied to the motor, for example, the magnetic flux density of the magnet is calculated from the induced voltage, By estimating the temperature of the magnet from the magnetic flux density, the temperature in the compressor can be estimated with high accuracy.

It is sectional drawing of the compressor 101 which concerns on Embodiment 1 of this invention. It is a figure which shows the outline of a structure in the control apparatus 14 which concerns on Embodiment 1 of this invention. It is the figure (the 1) showing the voltage waveform which concerns on Embodiment 1 of this invention in time. It is the figure (the 2) showing the voltage waveform which concerns on Embodiment 1 of this invention in time. It is the figure (the 3) which represented the voltage waveform which concerns on Embodiment 1 of this invention in time. It is sectional drawing of the compressor 101 which concerns on Embodiment 2 of this invention. It is a figure showing the structural example of the refrigerating-cycle apparatus which concerns on Embodiment 5 of this invention.

Hereinafter, a compressor and the like according to an embodiment of the invention will be described with reference to the drawings. Here, in FIG. 1 and the following drawings, the same reference numerals denote the same or corresponding parts, and are common to the whole text of the embodiments described below. And the form of the component represented by the whole specification is an illustration to the last, Comprising: It does not limit to the form described in the specification. In particular, the combination of the components is not limited to the combination in each embodiment, and the components described in the other embodiments can be applied to another embodiment. In addition, the upper side in the figure will be described as “upper side” and the lower side will be described as “lower side”. In the drawings, the size relationship of each component may be different from the actual one. The level of temperature, pressure, etc. is not particularly determined in relation to absolute values, but is relatively determined in the state, operation, etc. of the system, apparatus, and the like.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view of a compressor 101 according to Embodiment 1 of the present invention. Based on FIG. 1, the structure of the compressor 101 in this Embodiment is demonstrated. The compressor 101 of this Embodiment becomes a component of the refrigerating-cycle apparatus used as a refrigerator, a freezer, a vending machine, an air conditioning apparatus, a freezing apparatus, a hot water supply apparatus etc., for example.

In the compressor 101, the shell 1 is a container that accommodates the electric motor 3, the compression mechanism 5 and the like inside. The shell 1 is a sealed container that seals the inside. The suction pipe 2 is installed in the shell 1. The suction pipe 2 is a pipe that guides the refrigerant 10 that is the fluid to be compressed into the suction space in the shell 1 (compressor 101). The electric motor 3 is driven by power supply (voltage application) to rotate the main shaft 4. The electric motor 3 of the present embodiment is configured by a brushless DC motor. The electric motor 3 has a rotor 3a and a stator 3c. A permanent magnet 3b is inserted into the rotor 3a. The rotor 3 a is connected to the main shaft 4. Further, the stator 3 c is fixed to the shell 1. The main shaft 4 rotates with the rotation of the rotor 3 a of the electric motor 3, and transmits the driving torque generated by the rotation to the compression mechanism unit 5.

The compression mechanism 5 has a compression chamber formed by combining a fixed scroll and a swing scroll. The orbiting scroll is connected to the main shaft 4 and rotates with the rotation of the main shaft 4. When the rocking scroll is swung with respect to the fixed scroll fixed to the shell 1, the volume of the compression chamber is gradually reduced, and the refrigerant flowing from the suction space into the compression chamber is compressed. As shown in FIG. 1, in the shell 1, the compression mechanism part 5 is arrange | positioned at the upper side, and the electric motor 3 is arrange | positioned at the lower side. The discharge space 6 is a space that becomes a high-pressure refrigerant atmosphere by the refrigerant flowing out of the compression mechanism unit 5. The discharge space 6 communicates with the discharge pipe 7, and the refrigerant that has flowed into the discharge space 6 is discharged from the compressor 101 through the discharge pipe 7. Here, in this embodiment, R32 refrigerant that is HFC refrigerant or R744 refrigerant that is carbon dioxide refrigerant is used as the refrigerant 10 that is the fluid to be compressed by the compressor 101 in this embodiment.

The suction temperature thermistor 11 detects the temperature of the suction pipe 2 of the compressor 101 (the temperature of the refrigerant 10 sucked into the compressor 101). The discharge temperature thermistor 12 detects the temperature of the discharge pipe 7 (the temperature of the refrigerant 10 discharged from the compressor 101). Further, the oil temperature thermistor 13 indirectly detects the temperature (oil temperature) of the refrigerating machine oil inside the compressor 101 from the outside of the shell 1.

FIG. 2 is a diagram showing an outline of the configuration within the control device 14 according to Embodiment 1 of the present invention. The control device 14 according to the present embodiment controls the compressor 101. The control device 14 is electrically connected to the electric motor 3 in the compressor 101 via the terminal 8 and supplies electric power to the electric motor 3. Control for adjusting the rotational speed of the electric motor 3 is performed by controlling the electric power supplied by controlling the phase and the like. Here, the control device 14 according to the present embodiment includes a control unit and a drive unit. The control unit includes a microcomputer having a control calculation processing means such as a CPU (Central Processing Unit), a storage means (not shown), etc. ing. Then, based on the physical quantities related to the detection of various sensors, the control arithmetic processing means executes processing based on the program data to realize control. Further, the drive unit includes an inverter circuit that generates power to be supplied to the electric motor 3 based on a signal sent from the control unit. Further, the control device 14 of the present embodiment has a detection circuit for detecting a voltage related to the electric motor 3. For example, when the electric motor 3 of the present embodiment is a brushless DC motor, the potential difference (UN, VN) between the U phase, the V phase, and the W phase and the neutral point potential N (N potential of the bus voltage). , W−N), the voltage divided by the detection circuit is applied to the control unit, so that the control unit can detect the voltage generated in the electric motor 3. Here, although the control device 14 of the present embodiment is described as a device constituting the compressor 101, for example, the control device 14 may be configured as a part of a device different from the compressor 101.

Next, the driving operation of the compressor 101 according to the present embodiment will be described. When electrical input is given from the outside of the compressor 101 to the stator 3c of the electric motor 3 from the control device 14, rotational torque is generated in the rotor 3a. When the rotor 3a rotates, the main shaft 4 fixed to the rotor 3a rotates. The rotational torque generated by the rotation of the main shaft 4 is transmitted to the compression mechanism unit 5 and the compression mechanism unit 5 is driven. When the compression mechanism unit 5 is driven, the refrigerant in the suction space flows into the compression chamber of the compression mechanism unit 5. In the compression chamber, the refrigerant is compressed by continuously reducing the volume of the compression chamber. Then, it becomes a high-temperature and high-pressure refrigerant and flows out of the compression chamber. The high-temperature and high-pressure refrigerant is discharged out of the compressor 101 from the discharge pipe 7 through the discharge space 6.

Next, the state of the refrigerant 10 when the compressor 101 is driven will be described. The refrigerant 10 flows into the compressor 101 from the suction pipe 2 in a low pressure and low temperature state (for example, about 10 to 20 ° C.). The refrigerant that has flowed in cools the motor 3, the bearing portion 9, and the lubricating oil 15, and is taken into the compression mechanism portion 5. Thereafter, the refrigerant is compressed into a high-temperature and high-pressure refrigerant. However, the temperature of the refrigerant after compression is about 20 ° C. higher than that of the conventional R22 refrigerant.

FIGS. 3 to 5 are diagrams that temporally represent the voltage waveforms according to the first embodiment of the present invention. 3 is a waveform of a voltage (applied voltage) applied to the compressor 101 by the control device 14. On the other hand, the B wave shown in FIG. 4 is a waveform of an induced voltage generated by the electric motor 3 of the compressor 101 which is a permanent magnet type electric motor. In a normal control state, the induced voltage (B wave) is hidden behind the applied voltage (A wave) and cannot be detected. Therefore, as shown in FIG. 5, it is possible to detect the induced voltage by providing a non-energized section in which the application of the voltage from the control device 14 is stopped.

The magnitude of the induced voltage changes according to the rotation speed (drive frequency) of the compressor 101, the magnetic flux density of the permanent magnet 3b, and the number of turns of the coil of the stator 3c. Here, the control device 14 can grasp the rotation speed of the compressor 101. The number of turns of the stator 3c is determined in advance. For this reason, the control apparatus 14 can obtain | require the magnetic flux density of the permanent magnet 3b based on the rotation speed of the electric motor 3 (compressor 101), and the magnitude | size of an induced voltage. Here, the magnetic flux density of the permanent magnet 3b has a temperature gradient. Therefore, the control device 14 obtains a relationship between the magnetic flux density of the permanent magnet 3b and the temperature in advance, and has data indicating the relationship. It becomes possible to estimate the temperature of the permanent magnet 3b (the temperature of the electric motor 3, the temperature in the shell 1) from the magnetic flux density.

As shown in FIG. 1, the rotor 3 a rotates inside the stator 3 c of the electric motor 3 inside the shell 1 (compressor 101) and is in close contact with the main shaft 4. For this reason, in order to estimate the temperature of the motor 3, the temperature of the lubricating oil 15 in the shell 1 (compressor 101), etc., the suction temperature thermistor 11, the discharge temperature thermistor 12, the oil temperature attached to the outside of the compressor 101 Compared to the case where the temperature in the shell (compressor 101) is estimated from the temperature related to the detection of the thermistor 13, it can be estimated with high accuracy.

As described above, according to the compressor 101 of the first embodiment, when the control device 14 supplies power to the compressor 101 main body, the non-energized section is provided so as to perform control to stop the voltage application. Thus, the induced voltage generated by the electric motor 3 can be detected. For this reason, it is possible to estimate the temperature of the electric motor 3 and the bearing portion 9 in the shell 1 with high accuracy and to estimate the estimation error at a low level. Driving can be continued. Further, for example, in order to improve the performance of the compressor 101, it is not necessary to select an alloy containing a large amount of heavy rare earth metal such as dysprosium, which is difficult to obtain in the material of the permanent magnet 3b. Can measure. Moreover, since it is not necessary to select an alloy containing lead or the like as the material of the bearing portion 9 in order to improve the slidability, the environmental load can be reduced.

Embodiment 2. FIG.
FIG. 6 is a cross-sectional view of the compressor 101 according to Embodiment 2 of the present invention. In FIG. 6, the same reference numerals as those in FIG. As shown in FIG. 6, in the compressor 101 of the present embodiment, the suction pipe 2 is in direct communication with the compression mechanism unit 5. The refrigerant compressed by the compression mechanism unit 5 is discharged from the discharge pipe 7 after being opened to the discharge space 6 where the electric motor 3, the bearing unit 9, and the lubricating oil 15 are located below the compression mechanism unit 5. As described above, the compressor 101 having a different component arrangement from the compressor 101 described in the first embodiment also exists depending on the application.

In the compressor 101 configured as described above, when the R32 refrigerant and the R744 refrigerant are used as the gas to be compressed, the electric motor 3, the bearing portion 9, the lubricating oil 15 and the like located in the discharge space 6 become high temperature. It is difficult to estimate the temperature of each part in the compressor 101 using only the suction temperature thermistor 11, the discharge temperature thermistor 12, and the oil temperature thermistor 13.

Therefore, also in the compressor 101 having the structure as in the present embodiment, as described in the first embodiment, a voltage provided with a non-energized section is applied, and an induced voltage is detected in the non-energized section. The compressor 101 can be effectively protected by estimating the temperature of the electric motor 3 with high accuracy based on the induced voltage.

Embodiment 3 FIG.
Although not specified in the first and second embodiments, the material of the permanent magnet 3b is a rare earth magnet containing neodymium (neodymium). A rare earth magnet containing neodymium has a high magnetic flux density and a large magnetic force.

As described in the first embodiment, the magnitude of the induced voltage varies depending on the magnetic flux density of the permanent magnet 3b and the number of turns of the stator 3c. For example, the contribution of the magnetic flux density of the permanent magnet 3b to the induced voltage is increased by employing a rare earth magnet containing neodymium having a magnetic flux density exceeding 1T in the permanent magnet 3b of the electric motor 3. Since the magnetic flux density of the permanent magnet 3b has temperature characteristics, the contribution of the magnetic flux density of the permanent magnet 3b to the induced voltage increases, so that the temperature of the permanent magnet 3b is easily reflected in the magnitude of the induced voltage. Therefore, the sensitivity of the temperature of the electric motor 3 based on the induced voltage is improved, and the temperature estimation accuracy of the electric motor 3 can be further increased.

Embodiment 4 FIG.
In the first to third embodiments described above, the compressor 101 is shown as an example of a scroll compressor. However, the present invention is not limited to this, and the present invention is not limited to this, and may be applied to other types of compressors and the like. Can be applied.

Embodiment 5 FIG.
FIG. 7 is a diagram illustrating a configuration example of a refrigeration cycle apparatus according to Embodiment 5 of the present invention. Here, FIG. 7 shows an air conditioner as the refrigeration cycle apparatus. The air conditioner of FIG. 7 connects an outdoor unit (outdoor unit) 100 and an indoor unit (indoor unit) 200 through a gas refrigerant pipe 300 and a liquid refrigerant pipe 400. The outdoor unit 100 includes the compressor 101, the four-way valve 102, the outdoor heat exchanger 103, the expansion valve 104, and the outdoor blower 105 described in the first to fourth embodiments. The indoor unit 200 has an indoor heat exchanger 201.

Compressor 101 compresses and discharges the sucked refrigerant. Here, although not particularly limited, the capacity of the compressor 101 (the amount of refrigerant sent out per unit time) is changed by arbitrarily changing the operating frequency of the compressor 101 using, for example, an inverter circuit. You may be able to. The four-way valve 102 is, for example, a valve for switching the refrigerant flow between the cooling operation and the heating operation.

The outdoor heat exchanger 103 performs heat exchange between the refrigerant and air (outdoor air). For example, it functions as an evaporator during heating operation, evaporating and evaporating the refrigerant. Moreover, it functions as a condenser during the cooling operation, and condenses and liquefies the refrigerant.

An expansion valve 104 such as a throttle device (flow rate control means) expands the refrigerant by decompressing it. For example, in the case of an electronic expansion valve or the like, the opening degree is adjusted based on an instruction from a control means (not shown) or the like. The indoor heat exchanger 201 performs heat exchange between air to be air-conditioned and a refrigerant, for example. During heating operation, it functions as a condenser and condenses and liquefies the refrigerant. Moreover, it functions as an evaporator during cooling operation, evaporating and evaporating the refrigerant.

As described above, according to the refrigeration cycle apparatus of the fifth embodiment, by using the compressor 101 described in the first to fourth embodiments as a constituent element, the entire apparatus can be operated efficiently. it can.

In Embodiment 4 described above, the refrigeration cycle apparatus taking the air conditioner as an example has been described, but it can also be used for a refrigeration apparatus, a hot water supply apparatus, and the like.

1 shell, 2 suction pipe, 3 motor, 3a rotor, 3b permanent magnet, 3c stator, 4 main shaft, 5 compression mechanism part, 6 discharge space, 7 discharge pipe, 8 terminal, 9 bearing part, 10 refrigerant, 11 suction Temperature thermistor, 12 Discharge temperature thermistor, 13 Oil temperature thermistor, 14 Control device, 15 Lubricating oil, 100 Outdoor unit, 101 Compressor, 102 Four-way valve, 103 Outdoor heat exchanger, 104 Expansion valve, 105 Outdoor blower, 200 Indoor unit 201, indoor heat exchanger, 300 gas refrigerant piping, 400 liquid refrigerant piping.

Claims

A sealed container as an outer shell,
A compression mechanism that is installed in the sealed container and compresses the fluid that flows in and discharges the fluid to the outside;
An electric motor having a magnet and supplying power to the compression mechanism;
A compressor comprising: a control device that controls a power supplied to the motor by applying a voltage provided with a non-energized section for detecting an induced voltage of the motor to the motor.
The compressor according to claim 1, wherein the electric motor is a permanent magnet type brushless DC motor.
The compressor according to claim 1 or 2, wherein the electric motor is installed in a high-pressure side space serving as an atmosphere of gas flowing out from the compression mechanism section in the sealed container.
The compressor according to any one of claims 1 to 3, wherein the magnet of the electric motor is a rare earth magnet containing neodymium.
The compressor according to any one of claims 1 to 4, wherein the fluid is an R32 refrigerant or an R744 refrigerant.
The compressor according to any one of claims 1 to 5, wherein the control device performs a process of estimating a temperature in the compressor based on the induced voltage detected in the non-energized section.
7. A refrigeration cycle apparatus in which the compressor, the condenser, the expansion device, and the evaporator according to any one of claims 1 to 6 are connected by a refrigerant pipe to constitute a refrigerant circuit.
A compressor provided with a hermetic container serving as an outer shell, a compression mechanism part that is installed in the hermetic container, compresses the refrigerant that has flowed in, and is discharged to the outside, and a motor that has a magnet and supplies power to the compression mechanism part Control method,
Applying a voltage with a non-energized section to the motor;
And a step of estimating a temperature in the compressor based on an induced voltage of the electric motor detected in the non-energized section.
The compression according to claim 8, wherein the magnetic flux density of the magnet is obtained based on the rotation speed of the electric motor and the magnitude of the induced voltage, and the temperature in the compressor is estimated based on the relationship between the magnetic flux density of the magnet and the temperature. How to control the machine.