JP2012082763A - Refrigeration cycle apparatus using inverter-integrated electric motor compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigeration cycle apparatus using an inverter-integrated electric compressor that can actively cool an inverter so that the inverter can be used even in a higher temperature atmosphere and can also contribute to increasing heating capacity when an ambient temperature is equal to or lower than -10°C.SOLUTION: The refrigeration cycle apparatus includes a liquid coolant pipe 5 connected to the compressor 1, which branches off right after a condensor 2. The compressor includes a liquid coolant passage 21 in communication with the liquid coolant pipe and a flow rate control valve 22 opening and closing the liquid coolant pipe. A back surface of an inverter installation wall is configured to cooled by an intake coolant and an inside of the inverter installation wall is configured to be cooled by the liquid coolant passing through the liquid coolant passage. Accordingly, the apparatus cools the inverter more effectively using the intake coolant and the liquid coolant, heats the liquid coolant pipe by a heating means under a low temperature and can thus increase an discharge capacity of a compressing mechanism part without generating excessive liquid compression.

Description

  The present invention relates to a refrigeration cycle using an inverter-integrated electric compressor in which an inverter is integrated with a body container containing a compression mechanism and an electric motor.

  An inverter-integrated electric compressor is used for cooling a car air conditioner for a hybrid vehicle, and various types have been proposed (see, for example, Patent Documents 1, 2, and 3).

  FIG. 5 shows an electric compressor described in Patent Document 1. This electric compressor houses a compression mechanism 105 and an electric motor 106 in a main body casing 101, and an inverter 103 in an inverter case portion of the main body casing 101. Configured. Here, the inverter 103 is provided on the opposite side of the electric motor 106 through the partition wall of the inverter case portion, and is cooled by the refrigerant sucked into the main body casing 101, and then the refrigerant further cooled the electric motor 106. Thereafter, the low-pressure compressor is sucked into the compression mechanism unit 105.

  6 is an electric compressor described in Patent Document 2. This electric compressor is opposite to the electric motor 12 with the compression mechanism unit 11, the main body casing 10 containing the electric motor 12, and the compression mechanism unit 11 interposed therebetween. An inverter case 13 containing an inverter 14 on the side is fastened with bolts or the like in the axial direction. Then, the refrigerant sucked into the main body casing 10 is once guided to a suction passage provided in the inverter case 13, cools the inverter 14, and then flows into the compression mechanism 11. The refrigerant gas compressed by the compression mechanism 11 is discharged from a discharge port provided in the main body casing 10 after the motor 12 is cooled. This is a so-called high-pressure compressor.

  Further, FIG. 7 shows an electric compressor described in Patent Document 3 and a refrigeration cycle apparatus using the electric compressor, which stores a compression mechanism Cp and an electric motor Mo in a main body casing 100, and an inverter Ic on it. The inverter Ic is cooled with a refrigerant from an injection circuit in the refrigeration cycle constituted by the condenser 200, the decompressor 400, the evaporator 500, and the liquid / liquid separation 310, or the refrigeration cycle described above. It is configured to be cooled by any of the refrigerant drawn from the apparatus.

Japanese Patent Laid-Open No. 2003-129983 JP 2007-290444 A JP 2002-5024 A

  The structure described in Patent Document 1 is sucked into the compression section after exchanging heat with the heat generating parts of the inverter and the electric motor by the sucked refrigerant, so that the volume efficiency is lowered by the rise of the sucked refrigerant temperature, and the performance of the compressor is reduced. It has a big effect.

On the other hand, the structure described in Patent Document 2 is different from the structure described in Patent Document 1 in that the suction refrigerant is used only for inverter cooling, and the lubricating oil separator is an empty body container in which the electric motor is accommodated. Since the space can be provided, there are great advantages in terms of performance and the size of the aircraft container. However, the suction refrigerant passage provided in the inverter case has a partition wall and is close to the discharge refrigerant passage, and the inverter case is connected to the compressor unit, which is a heating element, and the fuselage container containing the electric motor through the seal portion, so that heat conduction is achieved. As a result, the inverter case is heated, and it is necessary to devise an inexpensive structure together with an efficient cooling means in which the temperature of the inverter case is difficult to rise even in a higher temperature atmosphere.

  Further, in the configuration described in Patent Document 3, in the proposal of using the high-pressure liquid refrigerant from the injection circuit of the refrigeration cycle for cooling the inverter, the cooling passage and the heat insulating structure are extremely complicated. The method of controlling the heating degree of the refrigerant using the flow rate control valve has significant problems in terms of cost and size.

  On the other hand, a car air conditioner system equipped with an inverter-integrated electric compressor has recently been closed up as a heating function for electric vehicles. That is, in early electric vehicles, water is heated by electricity and used for heating, so that there is a problem that the amount of electricity used is large and the cruising distance in one charge is halved during heating. As efficient heating, it is better to devise a refrigeration cycle and heat it with outside air heat like a home air conditioner. However, when the outside air falls below −10 ° C., the heating capacity is insufficient. As a solution, there is a method of injecting high-pressure liquid refrigerant in the refrigeration cycle into the compression chamber in the middle of compression to increase the discharge amount of the compressor, which is well known for constant speed compressors, but has a wide rotation speed Electric compressors that change over a range have many problems such as reliability assurance for liquid compression, size and cost increase.

  The present invention has been made under such a background of the prior art, and in a refrigeration cycle equipped with an inverter-integrated compressor that cools an inverter with suction refrigerant, the inverter can be used even in a higher temperature atmosphere. A refrigeration cycle structure equipped with a compact, high-efficiency, low-cost and highly reliable inverter-integrated electric compressor that can be further cooled and contribute to increased heating capacity at low outside temperatures of -10 ° C or lower It is to provide.

  In order to solve the above-mentioned conventional problems, the present invention is a refrigeration cycle apparatus in which an inverter-integrated electric compressor, a condenser, an expansion valve, and an evaporator are connected in a ring shape by piping, and is branched from immediately after the condenser. A liquid refrigerant pipe connected to the inverter-integrated electric compressor, the inverter-integrated electric compressor being disposed on a main body case housing the motor and the compression mechanism, an inverter case incorporating the inverter, and an inverter installation wall And a flow rate control valve that opens and closes the liquid refrigerant pipe, and the back surface of the inverter installation wall is inhaled. An inverter that is cooled by a refrigerant and that is cooled by liquid refrigerant passing through the liquid refrigerant passage when the flow control valve is opened inside the inverter installation wall. There is as equipped with the structure of the integrated electric compressor.

  As a result, when the temperature sensor on the inverter installation wall rises above the first set value or when the air conditioning system using the refrigeration cycle is necessary, the flow control valve is opened to effectively cool the inverter. At the same time, when the temperature sensor is at a temperature lower than the third set value, the liquid refrigerant pipe is heated by the heating means, so that the discharge capacity of the compressor can be increased without causing excessive liquid compression.

  According to the above configuration, the present invention has a simple configuration and can be actively lowered by the liquid refrigerant in addition to the suction refrigerant even under a condition where the temperature of the inverter rises, and an efficient refrigerant cooling effect can be obtained. Furthermore, by allowing the liquid refrigerant to flow, the compressed gas can be cooled by the heat of vaporization of the liquid, and the discharge gas temperature of the compressor, which contributes to the rise in the inverter temperature, can be reduced. Exists.

  As a result, in order to reduce the heat generation of the conventional inverter, the cooling capacity is insufficient due to a decrease in the number of revolutions to reduce the inverter load, and the adverse effect of the cooling stop due to the compressor stop due to an abnormal increase in ambient temperature, discharge temperature or inverter temperature No longer bring

  In addition, in response to insufficient heating capacity at low outside air temperature, the refrigerant discharge rate is increased without significantly increasing the compression load input by injecting refrigerant mixed with liquid components into the compression chamber during compression. It can be a highly efficient heating capacity increasing means.

Refrigeration cycle diagram of a refrigeration cycle apparatus equipped with an inverter-integrated electric compressor according to Embodiment 1 of the present invention. Sectional drawing of the inverter integrated electric compression mechanism part of Embodiment 1 Refrigeration cycle diagram of a refrigeration cycle apparatus equipped with an inverter-integrated electric compressor in the second embodiment Sectional drawing of the inverter integrated electric compression mechanism part of Embodiment 2 Sectional drawing of the inverter-integrated electric compressor of Conventional Example 1 Sectional view of the inverter-integrated electric compressor of Conventional Example 2 Refrigeration cycle diagram of a refrigeration cycle apparatus equipped with the inverter-integrated electric compressor of Conventional Example 3

  A first invention is a refrigeration cycle apparatus in which an inverter-integrated electric compressor, a condenser, an expansion valve, and an evaporator are connected in an annular shape by piping, branching immediately after the condenser, and the inverter-integrated electric compressor The inverter-integrated electric compressor includes a main body case that houses an electric motor and a compression mechanism, an inverter case that incorporates an inverter, a temperature sensor that is disposed on an inverter installation wall, and the liquid A liquid refrigerant passage communicating with the refrigerant pipe and opened in a compression chamber in the middle of compression of the compression mechanism section and a flow rate control valve for opening and closing the liquid refrigerant pipe are provided, and the back surface of the inverter installation wall is cooled by the intake refrigerant. The inverter installation wall has an inverter-integrated electric compressor that is cooled by liquid refrigerant passing through the liquid refrigerant passage when the flow control valve is opened. Are you.

  According to a second aspect of the invention, the flow control valve is installed in the inverter case and operates by receiving power supply and a communication signal from the inverter.

  According to a third aspect of the present invention, the flow control valve is opened when the temperature sensor rises above the first set value, and closed when the temperature sensor falls below the second set value at a temperature lower than the first set temperature. It is as a configuration that works.

  According to a fourth aspect of the present invention, the flow rate control valve is opened when the temperature sensor rises above the first set value, and is closed when the temperature sensor falls below the second set value at a temperature lower than the first set temperature. It is as a configuration that works.

  In the fifth invention, the flow control valve is constituted by an electromagnetic on-off valve.

  In a sixth aspect of the present invention, the compression mechanism is an asymmetric scroll system, and the liquid refrigerant passage is opened to the compression chamber having the smaller maximum suction volume among the pair of compression chambers.

  In the seventh invention, the heating means of the liquid refrigerant pipe is constituted by a PTC heater.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a refrigeration cycle diagram of a refrigeration cycle apparatus using an inverter-integrated electric compressor according to Embodiment 1 of the present invention.

  In FIG. 1, this refrigeration cycle apparatus is configured by connecting an inverter-integrated electric compressor (hereinafter referred to as a compressor) 1, a condenser 2, an expansion valve 3, and an evaporator 4 in an annular shape by piping. The body-type electric compressor 1 is connected to a liquid refrigerant pipe 5 that branches from immediately after the condenser 2 and that introduces into the compressor 1 liquid refrigerant that has radiated heat and is condensed and liquefied by the condenser 2.

  FIG. 2 is a partial sectional view of inverter-integrated electric compressor 1 according to Embodiment 1 of the present invention.

  The compressor 1 includes an inverter case including a main body case 13 housing an electric motor 11 and a compression mechanism unit 12, an inverter 16 connected to a power line 14 for supplying power from the outside and a communication line 15 for receiving and transmitting communication signals. 17 and a temperature sensor 19 disposed on the inverter installation wall 18, and an intake refrigerant passage 20 through which the refrigerant from the liquid refrigerant pipe 5 is sucked is formed on the back surface of the inverter installation wall 18. Cooled by the suction refrigerant. A liquid refrigerant passage 21 branches from the liquid refrigerant pipe 5 immediately after the condenser 2 and is connected to the refrigerant refrigerant pipe 5. The liquid refrigerant passage 21 is formed inside the inverter installation wall 18 and is compressed in the compressor via the flow rate control valve 22. The compression chamber 23 is open. The flow control valve 22 is installed inside the inverter case 17 and is an electromagnetic on-off valve that operates by receiving electric power from the inverter 16.

  Next, the operation will be described.

  The inverter 16 has a power element 16a for converting a DC voltage supplied from the power line 14 into an AC, is fixed in close contact with the inverter installation wall 18 and is cooled by the suction refrigerant in the suction refrigerant passage 20 on the back surface. The generated heat is conducted to the wall 18 to be cooled. The temperature sensor 19 is a sensor for monitoring the temperature of the inverter installation wall 18, and the inverter installation wall 18 is normally controlled to be cooled to 100 ° C. or less.

  Here, for example, assuming that the inverter-integrated electric compressor is mounted in an engine room having an ambient temperature of 150 ° C., the inverter installation wall 18 conducts the ambient temperature, and the first set temperature is 80 ° C. The temperature exceeds this value.

  At this time, the flow control valve 22 is opened by receiving a signal from the temperature sensor 19, and the liquid refrigerant flows into the liquid refrigerant passage 21, and the inverter installation wall 18 is also deprived of heat by this liquid refrigerant, and has a certain balance. It is cooled down slowly until the temperature is reached. When the second set temperature is 50 ° C., the flow control valve 22 is closed when the vehicle is cooled to a temperature lower than the second set value due to a change in the driving speed of the vehicle, the outside air temperature, or the operating conditions of the electric compressor. It is set as control to valve.

(Embodiment 2)
FIG. 3 is a refrigeration cycle diagram of a refrigeration cycle apparatus using an inverter-integrated electric compressor according to Embodiment 2 of the present invention.

In FIG. 3, this refrigeration cycle apparatus is configured by connecting an inverter-integrated electric compressor 1, an indoor condenser 101, a throttle valve 102, an outdoor evaporator 103, an expansion valve 104, and an indoor evaporator 105 in an annular shape by piping. The inverter-integrated electric compressor 1 is a liquid for branching from between the indoor condenser 101 and the throttle valve 102 to dissipate heat and condense and liquefy the liquid refrigerant into the inverter-integrated electric compressor 1. A refrigerant pipe 106 is connected.

  The liquid refrigerant pipe 106 is provided with a heating means 107. Specific examples of the heating means 107 include a PTC heater and an electromagnetic induction heating (IH) heater for electric use, and exhaust heat for vehicle parts such as an engine, a drive motor and a drive. Candidates such as the use of inverters are candidates.

  FIG. 4 is a partial cross-sectional view of an inverter-integrated electric compressor according to Embodiment 2 of the present invention.

  Basically, the structure is almost the same as in FIG. 3, but the heating means 107 described above is installed in the liquid refrigerant pipe 106.

  Next, the operation will be described.

  The configuration of the refrigeration cycle in FIG. 3 is a configuration that assumes heating for a car air conditioner for an electric vehicle that does not have a heat source, for example, the indoor condenser 101 is a high-temperature heat source for indoor heating, and the indoor evaporator 105 is a low-temperature that performs dehumidification. The outdoor evaporator 103 is a heat source that takes heat from outside air and heats the room.

  If the outside air is about 20 ° C. to −5 ° C., sufficient heating can be performed with the current refrigerant. However, when the outside air temperature becomes −10 ° C. or lower, the refrigerant evaporates further and absorbs heat. When the pressure is low, that is, when the density is low, the circulating weight per unit time is reduced, and the amount of heat released into the room becomes insufficient.

  As one of means for increasing the heating capacity in such a case, there is liquid refrigerant injection (injection) into the compression chamber 23 during the compression process described above, and in this embodiment, the above-described operation is performed via the communication line 15 from the outside. A signal for opening the flow control valve 22 is received, and the discharge amount of the compression mechanism 12 is increased. Thereby, the refrigerant | coolant circulation amount which passes the indoor condenser 101 increases, and heating capability improves.

  In this embodiment, the compression mechanism unit 12 is an asymmetric type scroll compressor and starts compression from different maximum suction volumes. Therefore, the pressures of the pair of compression chambers are not the same. The above-described liquid injection (injection) is performed only on the compression chamber pressure side where the maximum suction volume is small, that is, the compression chamber pressure is small, and the pressure is increased by the injection to promote the pressure balance of both compression chambers (see FIG. (Omitted).

  When the outside air temperature is low and the heating capacity is insufficient even at the maximum number of revolutions, when the request signal for expanding the discharge capacity is input as a communication signal to the inverter 16 in the inverter-integrated electric compressor 1 as an air conditioner system, the flow control valve 22 is The valve is opened, and the liquid refrigerant is injected into the compression chamber 23 of the compression mechanism unit 12 during the aforementioned compression process.

  At this time, the liquid refrigerant absorbs the heat generated by the inverter 16 and also takes away the heat of the compressed gas and vaporizes. However, if the ratio of the injected liquid refrigerant is too large, it cannot be vaporized and remains as a liquid component, resulting in a liquid mixed compression state. Sometimes. Therefore, the pressure may abnormally increase for the gas compressor, and the load input may increase abnormally.

In the present embodiment, the temperature sensor 19 installed on the inverter installation wall 18 is used to monitor the temperature of the inverter installation wall 18 and to prevent liquid compression when the third set value is 10 ° C. or less, for example. For the purpose of increasing the internal energy (enthalpy) of the refrigerant in addition to increasing the amount of refrigerant circulating for heating, the heating means 107 installed in the liquid refrigerant pipe 106 is heated to partially vaporize the liquid refrigerant in advance. A communication signal is transmitted from the inverter 16 in order to activate the. At this time, when the heating means 107 is, for example, a PTC heater, if the temperature is low, the resistance is small and a large amount of heat is generated, but if the temperature is high, the resistance value naturally rises as a characteristic and the heat generation amount decreases. The refrigerant temperature can be self-controlled to about 30 ° C., for example. As a result, the amount of refrigerant sucked as a compressor increases at least due to liquid injection (injection), and the internal energy is increased by the heating means 107, so that the heating capacity for radiating heat to the indoor condenser 101 side is greatly increased. I can do it.

  As described above, in the refrigeration cycle apparatus equipped with the inverter-integrated electric compressor according to the present invention, the inverter installation wall is provided as necessary as a refrigeration cycle as compared with the conventional refrigeration cycle built-in type electric compressor. The temperature can be reduced relatively arbitrarily. Therefore, the operable temperature range of the inverter with respect to the ambient temperature and the discharge temperature of the compressor is greatly improved, and inexpensive electronic components can be employed by expanding the inverter cooling region. In addition, the reliability of electronic components is improved by improving the cooling efficiency. As a result, it can be easily mounted on an environmental vehicle having an engine that tends to be relatively hot, and can be widely applied to low-cost environmental vehicles such as mild hybrid vehicles.

  Furthermore, for environmental vehicles that do not have a heat source such as an electric vehicle, the energy saving (high efficiency) of heating using outside air heat and the compressor corresponding to insufficient heating capacity at a low outside air temperature of about −20 ° C. This can be combined with an increase in the discharge amount, which can greatly improve the air conditioner for electric vehicles and contribute to the popularization of electric vehicles that do not emit exhaust gas.

DESCRIPTION OF SYMBOLS 1 Inverter integrated electric compressor 2 Condenser 3 Expansion valve 4 Evaporator 5 Liquid refrigerant piping 11 Electric motor 12 Compression mechanism part 13 Main body case 14 Power line 15 Communication line 16 Inverter 17 Inverter case 18 Inverter installation wall 19 Temperature sensor 20 Intake refrigerant path 21 Liquid refrigerant passage 22 Flow rate control valve 23 Compression chamber 101 Indoor condenser 103 Outdoor evaporator 105 Indoor evaporator 106 Liquid refrigerant pipe 107 Heating means

Claims (7)

An inverter-integrated electric compressor, a condenser, an expansion valve, and an evaporator connected in a ring by a pipe, and a liquid refrigerant pipe branched from immediately after the condenser and connected to the inverter-integrated electric compressor The inverter-integrated electric compressor includes a main body case that houses an electric motor and a compression mechanism, an inverter case that incorporates an inverter, a temperature sensor that is disposed on an inverter installation wall, and a compression that communicates with the liquid refrigerant pipe. A liquid refrigerant passage opened in the compression chamber in the middle of compression of the mechanism part and a flow rate control valve for opening and closing the liquid refrigerant pipe are provided, and the back surface of the inverter installation wall is cooled by suction refrigerant and the interior of the inverter installation wall Is a refrigeration cycle apparatus using an inverter-integrated electric compressor cooled by liquid refrigerant passing through the liquid refrigerant passage when the flow control valve is opened. The refrigeration cycle apparatus using an inverter-integrated electric compressor according to claim 1, wherein the flow control valve is installed in the inverter case and operates upon receiving power supply and a communication signal from the inverter. The flow rate control valve is configured to open when the temperature sensor rises above a first set value, and to close when the temperature sensor falls below a second set value at a temperature lower than the first set temperature. Item 3. A refrigeration cycle apparatus using the inverter-integrated electric compressor according to Item 1 or 2. The flow control valve is opened by a communication signal from the outside, and when the temperature sensor is equal to or lower than a third set value at a temperature lower than the second set value, the heating means installed in the liquid refrigerant pipe is operated. A refrigeration cycle apparatus using the inverter-integrated electric compressor according to any one of claims 1 to 3, which is an inverter that transmits a communication signal. The refrigeration cycle apparatus using the inverter-integrated electric compressor according to any one of claims 1 to 4, wherein the flow control valve is an electromagnetic on-off valve. 6. The inverter integrated type according to claim 1, wherein the compression mechanism portion is an asymmetric scroll system, and a liquid refrigerant passage is opened in a compression chamber having a smaller maximum suction volume among the pair of compression chambers. A refrigeration cycle device that also cooks an electric compressor. The refrigeration cycle apparatus using the inverter-integrated electric compressor according to any one of the first to sixth aspects, wherein the heating means of the liquid refrigerant pipe is a PTC heater.