Electric compressor

Abstract

An electric compressor (10) comprises: a compression section (30); an electric motor (40); and a control unit (50). The control unit (50) includes a motor information detector (51) for detecting the speed and energy consumption of the electric motor (40) and is connected to an intake pressure sensor (61) for detecting the intake pressure of a refrigerant and an exhaust pressure sensor (62) for detecting the exhaust pressure of the refrigerant. The control unit (50) further comprises: a memory for storing a characteristic map; an estimation device (53); and an operating control unit (54). The characteristic map specifies a correlation between the intake pressure, the exhaust pressure, the speed, the energy consumption, and the dryness of the refrigerant drawn into the compression section (30).The estimating device (53) estimates the dryness of the refrigerant based on the characteristic map using the rotational speed and energy consumption, the intake pressure and the discharge pressure. The operating control (54) controls the operation of the electric motor (40) according to the dryness level.

Description

[0001] The present invention relates to an electric compressor. STATE OF THE ART

[0002] Japanese patent application No. 2009-192090 discloses a refrigerant circuit device. The refrigerant circuit device comprises a compressor (electric compressor), a condenser, a pressure control valve, an evaporator, and an accumulator. The refrigerant circuit device includes a refrigerant state estimation device and a discharge capacity control device. The compressor compresses the refrigerant and discharges it into the condenser. The condenser releases the heat from the refrigerant discharged by the compressor. The pressure control valve reduces the pressure of the refrigerant that has released heat in the condenser, causing it to expand. The evaporator vaporizes the refrigerant that has been depressurized and expanded by the pressure control valve. The accumulator separates a liquid refrigerant from the refrigerant discharged from the evaporator.The refrigerant, from which the liquid refrigerant is separated by the accumulator, is reintroduced into the compressor and compressed by it.

[0003] The refrigerant condition estimator estimates the dryness of the refrigerant being drawn into the compressor. The refrigerant condition estimator estimates the enthalpy of the refrigerant being drawn into the compressor based on the pressure and temperature of the refrigerant being discharged from the compressor and the temperature of the refrigerant detected in the evaporator. The refrigerant condition estimator estimates the dryness of the refrigerant being drawn into the compressor based on the enthalpy. The refrigerant circuit device controls the compressor drive based on the estimated dryness, using the discharge capacity control device.

[0004] However, if the refrigerant discharged from the electric compressor contains liquid refrigerant, it is difficult to estimate the dryness of the refrigerant being drawn into the electric compressor based on the refrigerant's temperature. In other words, the electric compressor can continue to operate, but there is a risk of liquid refrigerant being present in the refrigerant. The electric compressor could fail if it compresses the liquid refrigerant.

[0005] The present invention, which was developed taking into account the above-mentioned problem, aims to provide an electric compressor that can avoid malfunctions caused by the compression of a liquid refrigerant. SUMMARY

[0006] According to one aspect of the present invention, an electric compressor is provided comprising: a compression section configured to compress a refrigerant; an electric motor configured to drive the compression section; and a controller configured to control the electric motor. The controller includes a motor information detector configured to detect the speed and energy consumption of the electric motor. The controller is connected to an intake pressure sensor for detecting the intake pressure of the refrigerant being drawn into the compression section and an exhaust pressure sensor for detecting the exhaust pressure of the refrigerant being discharged from the compression section. The controller includes: a memory for storing a characteristic map; an estimation device; and an operating control.The characteristic map specifies a correlation between the intake pressure, discharge pressure, rotational speed, energy consumption, and dryness of the refrigerant being drawn into the compression section. The estimation device is configured to estimate the dryness of the refrigerant based on the characteristic map, using the rotational speed and energy consumption detected by the motor information detector, the intake pressure detected by the intake pressure sensor, and the discharge pressure detected by the discharge pressure sensor. The operating control is configured to control the operation of the electric motor according to the dryness estimated by the estimation device.

[0007] Further aspects and advantages of the invention will become apparent from the following description in conjunction with the accompanying drawings, which illustrate the principles of the invention by way of example. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The invention, together with its aims and advantages, can best be understood by reference to the following description of the exemplary embodiments in conjunction with the accompanying drawings, in which the following applies: Fig. 1 is a side view of a vehicle that includes a vehicle air conditioning system; Fig. 2 is a view showing a refrigerant circuit of the vehicle air conditioning system; Fig. Figure 3 is a sectional view of an electric compressor; Fig. 4 is a block diagram of a controller; and Fig. Figure 5 is a flowchart of a control process carried out by the controller. DETAILED DESCRIPTION OF THE EXECUTION EXAMPLES

[0009] The following describes an exemplary embodiment of an electric compressor. The electric compressor according to this embodiment is, in particular, a scroll compressor. The scroll compressor is part of a vehicle air conditioning system installed in a vehicle.

[0010] Fig. Figure 1 shows a vehicle 100, which includes a vehicle air conditioning system 101. The vehicle air conditioning system 101 climate-controls the interior of the vehicle 100.

[0011] As in Fig. As shown in Figure 2, the vehicle air conditioning system 101 comprises a refrigerant circuit C. The refrigerant circuit C includes a scroll compressor 10, which serves as an electric compressor, a condenser 11, an expansion valve 12, and an evaporator 13. In other words, the scroll compressor 10 is attached to the vehicle 100 and is contained within the vehicle air conditioning system 101. The refrigerant circuit C is filled with refrigerant and sealed. The refrigerant flows within the refrigerant circuit C. The refrigerant flows in this order through the scroll compressor 10, the condenser 11, the expansion valve 12, and the evaporator 13. The refrigerant then flows through the evaporator 13 to the scroll compressor 10. That is, the refrigerant circulates through the refrigerant circuit C.

[0012] Specifically, the gaseous refrigerant flows from the scroll compressor 10 into the condenser 11 at high temperature and high pressure. The condenser 11 is configured to condense the refrigerant. The condenser 11 releases heat from the refrigerant to its surroundings to condense it. More precisely, the condenser 11 condenses the gaseous refrigerant at high temperature and high pressure into a liquid refrigerant at low temperature and high pressure. That is, the liquid refrigerant at low temperature and high pressure flows out of the condenser 11.

[0013] The refrigerant flows from the condenser 11 to the expansion valve 12. More precisely, the liquid refrigerant flows into the expansion valve 12 at low temperature and high pressure. The expansion valve 12 is configured to reduce the pressure of the refrigerant. That is, the liquid refrigerant at low temperature and high pressure expands through the expansion valve 12 to become liquid refrigerant at low temperature and low pressure.

[0014] The refrigerant then flows from the expansion valve 12 into the evaporator 13. More precisely, the liquid refrigerant flows into the evaporator 13 at low temperature and low pressure. The evaporator 13 is configured to evaporate the refrigerant. The evaporator 13 absorbs heat from its surroundings and transfers this heat to the refrigerant, causing it to evaporate. More precisely, the evaporator 13 converts the liquid refrigerant at low temperature and low pressure into a gaseous refrigerant at high temperature and low pressure. The evaporator 13 cools its surroundings through this evaporation process. Subsequently, the refrigerant is drawn through the evaporator 13 into the scroll compressor 10.

[0015] As in Fig. As shown in Figure 3, the scroll compressor 10 comprises a housing 20, a compression section 30, an electric motor 40 for driving the compression section 30, and a control unit 50. The housing 20 accommodates a rotating shaft 21, a support part 22 which supports the rotating shaft 21 via a first bearing 71, the compression section 30, and the electric motor 40. In other words, the housing 20 accommodates the compression section 30, the electric motor 40, and the control unit 50.

[0016] The rotating shaft 21 has an eccentric shaft 21a at one end. The eccentric shaft 21a is in an eccentric position relative to an axis L1 of the rotating shaft 21 and extends in the direction of the axis L1 of the rotating shaft 21 (i.e., in the axial direction of the rotating shaft 21). The rotating shaft 21 is connected to a counterweight 21b via the eccentric shaft 21a.

[0017] The housing 20 comprises a motor housing 23, a fixed scroll base plate 24, an ejection housing 25 and an inverter cover 26.

[0018] The engine housing 23 comprises an end wall 23a, a circumferential wall 23b, and an intake port 23c. The engine housing 23 has opposite ends that define the engine housing 23 in the axial direction of the rotating shaft 21, and the end wall 23a forms one of the opposite ends of the engine housing 23. The circumferential wall 23b has a cylindrical shape and extends from the outer circumferential edge of the end wall 23a. The axial direction of the circumferential wall 23b corresponds to the axial direction of the rotating shaft 21.

[0019] The rotary shaft 21 is rotatably inserted into the end wall 23a via a second bearing 72. In this embodiment, one end and the other end of the rotary shaft 21 are supported by the end wall 23a and by the support part 22, respectively.

[0020] The intake port 23c is formed in the circumferential wall 23b. In other words, the housing 20 has the intake port 23c. The intake port 23c extends from the outer circumferential surface of the circumferential wall 23b. The intake port 23c is connected to the evaporator 13. The refrigerant flowing out of the evaporator 13 is drawn into the housing 20 through the intake port 23c. An intake pressure sensor 61 is attached to the intake port 23c. The intake pressure sensor 61 is configured to detect the pressure of the refrigerant being drawn into the housing 20 through the intake port 23c.

[0021] The circumferential wall 23b has opposite ends, and one of the opposite ends is connected to the end wall 23a. The fixed scroll base plate 24 is attached to the other end of the opposite ends of the circumferential wall 23b. The fixed scroll base plate 24 has opposite surfaces, and a fixed scroll spiral wall 24a extends from one of the opposite surfaces of the fixed scroll base plate 24. The fixed scroll spiral wall 24a extends from the fixed scroll base plate 24 into the circumferential wall 23b. The fixed scroll base plate 24 and the fixed scroll spiral wall 24a work together to form a fixed scroll spiral 31.

[0022] The fixed scroll base plate 24 has an ejection opening 24b. The ejection opening 24b extends through the fixed scroll base plate 24 in the thickness direction of the fixed scroll base plate 24.

[0023] The ejection housing 25 is connected to the other of the opposing surfaces of the fixed scroll base plate 24 via a seal 27. The seal 27 seals a gap between the ejection housing 25 and the fixed scroll base plate 24.

[0024] The ejection housing 25 has an ejection chamber 25a and an ejection port 25d. The housing 20 therefore has the ejection port 25d.

[0025] The ejection chamber 25a is defined by the ejection housing 25 and the fixed scroll base plate 24. The ejection chamber 25a is connected to the ejection opening 24b. The ejection housing 25 has an ejection 25e at a position facing the fixed scroll base plate 24. The ejection 25e is connected to the ejection opening 24b via the ejection chamber 25a.

[0026] The discharge port 25d is connected to the condenser 11. The refrigerant is discharged from the housing 20 through the discharge port 25d towards the condenser 11. A discharge pressure sensor 62 is attached to the discharge port 25d. The discharge pressure sensor 62 is configured to detect the pressure of the refrigerant being discharged through the discharge port 25d into the condenser 11.

[0027] The compression section 30 of the scroll compressor 10 compresses the refrigerant drawn in through the intake port 23c. The compression section 30 is located in a part of the motor housing 23 next to the fixed scroll base plate 24 in the axial direction of the rotating shaft 21. The compression section 30 comprises the fixed scroll spiral 31, a rotating spiral 32, and a compression chamber 30a.

[0028] The circumferential spiral 32 faces the fixed scroll spiral 31. The circumferential spiral 32 comprises a circumferential scroll base plate 32a, which faces the fixed spiral base plate 24, and a circumferential scroll spiral wall 32b, which extends from the circumferential scroll base plate 32a. The circumferential scroll spiral wall 32b extends from the circumferential scroll base plate 32a towards the fixed scroll base plate 24. The fixed scroll spiral 31 and the circumferential scroll spiral 32 are arranged such that the fixed scroll spiral wall 24a engages with the circumferential scroll spiral wall 32b.

[0029] A pressure plate 28 is attached between the circumferential scroll base plate 32a and the carrier part 22.

[0030] The circumferential scroll base plate 32a has opposing surfaces, and the circumferential scroll spiral wall 32b extends from one of the opposing surfaces of the circumferential scroll base plate 32a. The counterweight 21b is connected to the other of the opposing surfaces of the circumferential scroll base plate 32a via a third bearing 73. The circumferential scroll base plate 32a is supported by the eccentric shaft 21a via a bushing of the counterweight 21b and the third bearing 73 such that the circumferential scroll base plate 32a rotates relative to the eccentric shaft 21a.

[0031] The other surface of the circumferential scroll base plate 32a faces the pressure plate 28 and has four ring elements 33. Each of the ring elements 33 receives a rotation-locking pin 22a, which protrudes from the carrier part 22 and penetrates the pressure plate 28.

[0032] The fixed scroll spiral wall 24a interlocks with the circumferential scroll spiral wall 32b, so that the compression chamber 30a is formed between the fixed scroll spiral 31 and the circumferential scroll spiral 32. The compression chamber 30a is connected to the discharge opening 24b.

[0033] The electric motor 40 is housed in the motor casing 23. The electric motor 40 is arranged in a space (i.e., a motor chamber 23e) that is bounded by the support part 22, the end wall 23a, and the circumferential wall 23b of the motor casing 23. The motor chamber 23e is part of a space in the circumferential wall 23b and adjoins the end wall 23a. The motor chamber 23e is connected to the compression chamber 30a via a recess 23f formed in the inner circumferential surface of the circumferential wall 23b. The refrigerant drawn in from the intake port 23c flows in this sequence through the motor chamber 23e, the recess 23f, the compression chamber 30a, and the discharge chamber 25a, and is discharged from the discharge port 25d.

[0034] The electric motor 40 comprises a stator 41 and a rotor 42, which is mounted inside the stator 41. The rotating shaft 21 passes through the rotor 42. The rotor 42 rotates together with the rotating shaft 21. The stator 41 surrounds the rotor 42.

[0035] The electric motor 40 is configured to rotate the rotor 42, which in turn rotates the rotating shaft 21. The rotation of the rotating shaft 21 is transmitted to the rotating spiral 32 via the eccentric shaft 21a, the counterweight bushing 21b, and the third bearing 73. The anti-rotation pin 22a engages the inner circumferential surface of the ring element 33 to prevent the rotating spiral 32 from rotating about its axis. Accordingly, the rotating spiral 32 rotates relative to the fixed scroll spiral 31. The rotating spiral 32 rotates with the rotating scroll spiral wall 32b in contact with the fixed scroll spiral wall 24a. Consequently, the volume of the compression chamber 30a decreases with the rotation of the rotating spiral 32.

[0036] In the scroll compressor 10, the refrigerant drawn into the housing 20 through the intake port 23c is introduced through the motor chamber 23e and the recess 23f into the outermost circumferential section of the compression chamber 30a. The refrigerant is then compressed in the compression chamber 30a by the rotating movement of the spiral 32. The refrigerant compressed by the compression section 30 flows through the discharge opening 24b, the discharge chamber 25a, and the discharge 25e, and is discharged from the housing 20 through the discharge port 25d. In this way, the compression section 30 of the scroll compressor 10 compresses the refrigerant. The scroll compressor 10 compresses the refrigerant drawn in through the intake port 23c through the compression section 30 and expels the compressed refrigerant from the housing 20 through the discharge port 25d.This means that the refrigerant to be compressed by the compression section 30 is drawn into the housing 20 through the intake port 23c. The refrigerant compressed by the compression section 30 is expelled from the housing 20 through the discharge port 25d. The intake pressure sensor 61 detects the intake pressure of the refrigerant being drawn into the compression section 30, and the discharge pressure sensor 62 detects the discharge pressure of the refrigerant expelled from the compression section 30. The intake pressure is the pressure of the refrigerant at the intake port 23c. The discharge pressure is the pressure of the refrigerant at the discharge port 25d.

[0037] The inverter cover 26 is attached to the end wall 23a. The control unit 50 is housed in a space bounded by the inverter cover 26 and the end wall 23a.

[0038] As in Fig. As shown in Figure 4, the control unit 50 is connected to the electric motor 40, the intake pressure sensor 61, and the exhaust pressure sensor 62. The control unit 50 receives a value of the intake pressure detected by the intake pressure sensor 61 and a value of the exhaust pressure detected by the exhaust pressure sensor 62.

[0039] The controller 50 is configured to control the electric motor 40. More precisely, the controller 50 outputs a speed value, which serves as a command value, to the electric motor 40 in order to control it. The controller 50 is powered by a power supply source (not shown) located outside the housing 20. The controller 50 is driven by this power supply.

[0040] The controller 50 comprises a motor, a motor information detector 51, a memory 52, an estimation device 53, and an operating controller 54. The controller 50 includes a processor (not shown). Examples of processors include a central processing unit (CPU), a graphics processing unit (GPU), and a digital signal processor (DSP). The memory 52 comprises random-access memory (RAM) and read-only memory (ROM). The memory 52 stores program code, or instructions, that the processor follows to perform operations. The memory 52 includes all available media accessible by general-purpose or specialized computers. The controller 50 may include a hardware circuit, such as an application-specific integrated circuit (ASIC) or a field-programmable gate array (FPGA).The controller 50, which is a processing circuit, can include one or more processors that operate according to a computer program, one or more hardware circuits, for example an ASIC or an FPGA, or a combination thereof.

[0041] The motor information detector 51 detects the rotational speed and energy consumption of the electric motor 40. For example, the motor information detector 51 is connected to a speed sensor (not shown) and detects the rotational speed via the speed sensor. The motor information detector 51 detects the energy consumption of the electric motor 40 by calculating it based on the current and voltage supplied to the electric motor 40, for example, by an inverter device (not shown) of the controller 50. The controller 50 receives values ​​for the rotational speed and energy consumption of the electric motor 40, which are detected by the motor information detector 51. The rotational speed of the electric motor 40 is simply referred to as rotational speed. The energy consumption of the electric motor 40 is simply referred to as energy consumption.

[0042] While the scroll compressor 10 is operating, the controller 50 receives the intake and discharge pressure values ​​and obtains the speed and energy consumption values. The controller 50 continuously receives the intake and discharge pressure values ​​and obtains the speed and energy consumption values. In other words, the intake pressure, discharge pressure, speed, and energy consumption values ​​can change continuously over time. The controller 50 can receive the intake and discharge pressure values ​​and acquire the speed and energy consumption values ​​at regular time intervals. That is, the controller 50 should be configured to acquire the intake pressure, discharge pressure, speed, and energy consumption values, which may change according to the operating conditions of the scroll compressor 10.

[0043] Memory 52 stores a characteristic map. This map shows a correlation between the intake pressure, discharge pressure, rotational speed, energy consumption, and the dryness of the refrigerant being drawn into the compression section 30 of the scroll compressor. Dryness refers to the weight ratio of the gaseous components in the refrigerant. That is, refrigerant with lower dryness contains more liquid refrigerant. The characteristic map provides a unique dryness value for each combination of intake pressure, discharge pressure, rotational speed, and energy consumption in the scroll compressor 10. The dryness of the refrigerant being drawn into the compression section 30 is simply referred to as dryness.

[0044] The characteristic map is generated by simulating the operation of the scroll compressor 10 under several conditions. Specifically, the characteristic map is generated as follows: First, the values ​​for the intake pressure, discharge pressure, dryness, and rotational speed are defined. Then, the operation of the scroll compressor 10 is simulated to calculate the energy consumption required to achieve each combination of these defined values. The required energy consumption for each combination of values ​​is determined by varying these values. The simulation results are then sorted according to the dryness of the refrigerant to generate the characteristic map.

[0045] The estimating device 53 estimates the dryness of the refrigerant to be drawn into the compression section 30 based on the characteristic map. The estimating device 53 estimates the dryness of the refrigerant based on the characteristic map with reference to the values ​​input into the estimating device 53. More precisely, the estimating device 53 receives the values ​​of the rotational speed and energy consumption, which are detected by the motor information detector 51, and the values ​​of the intake pressure and the exhaust pressure, which are detected by the intake pressure sensor 61 and the exhaust pressure sensor 62, respectively. That is, the estimating device 53 estimates the dryness of the refrigerant using the rotational speed and energy consumption detected by the motor information detector 51, the intake pressure detected by the intake pressure sensor 61, and the exhaust pressure detected by the exhaust pressure sensor 62.More precisely, the estimating device 53 uses the values ​​of the intake pressure, the discharge pressure, the rotational speed, and the energy consumption to obtain the dryness corresponding to each of these values ​​in the characteristic map. The estimating device 53 estimates the obtained dryness as the dryness of the refrigerant to be drawn into the scroll compressor 10. The estimating device 53 does not estimate the dryness based on the temperature of the refrigerant.

[0046] The estimating device 53 is configured to measure the time elapsed since the activation of the electric motor 40. For example, the controller 50 includes a timer (not shown), and the estimating device 53 refers to the timer's measurement results. The estimating device 53 can also refer to the measurement results of a timer located outside the controller 50. The estimating device 53 estimates the dryness of the refrigerant after a predetermined time has elapsed since the activation of the electric motor 40. According to this embodiment, the predetermined time is the time until a detection error in the energy consumption of the electric motor 40, detected by the motor information detector 51, falls within an acceptable range. According to this embodiment, the predetermined time is preset in the controller 50.

[0047] The operating control unit 54 controls the operation of the electric motor 40 according to the dryness level estimated by the estimating device 53. More precisely, the operating control unit 54 stops the electric motor 40 if the dryness level estimated by the estimating device 53 lies outside a predetermined range. According to this embodiment, the predetermined range is the acceptable dryness range of the refrigerant compressed by the compression section 30. This predetermined range is preset in the operating control unit 54.

[0048] The operating control unit 54 does not control the operation of the electric motor 40 until the predetermined time has elapsed. In other words, the operating control unit 54 controls the operation of the electric motor 40 while the estimating device 53 estimates the dryness of the refrigerant.

[0049] The following describes the control of the electric motor 40 by the control unit 50 with reference to the Fig. 4 and Fig. 5 described.

[0050] When activating the in Fig. In the vehicle air conditioning system 101 shown, the electric motor 40 starts to work and the control unit 50 begins to control the electric motor 40.

[0051] In step S1, the controller 50 determines whether the predefined time since the activation of the electric motor 40 has elapsed. If the controller 50 determines that the predefined time since the activation of the electric motor 40 has not elapsed, the controller 50 executes step 1 again.

[0052] When the controller 50 determines that the predetermined time has elapsed since the activation of the electric motor 40, the controller 50 executes step 2. Specifically, in step S2, the estimating device 53 of the controller 50 estimates the dryness of the refrigerant based on the characteristic map using the motor speed and energy consumption values ​​detected by the motor information detector 51, as well as the intake pressure and exhaust pressure values ​​detected by the intake pressure sensor 61 and the exhaust pressure sensor 62.

[0053] The controller 50 then executes step S3. In step S3, the controller 50 determines whether the estimated dryness is within the predetermined range. If the estimated dryness is within the predetermined range, the controller 50 executes step S4. In step S4, the controller 50 determines whether the electric motor 40 is stopped. If the electric motor 40 is running, the process returns from step S4 to step S2, and the controller 50 executes step S2 again. In other words, if the estimated dryness is within the predetermined range, the controller 50's estimating device 53 estimates the dryness while the electric motor 40 is running.

[0054] If, in step S3, the controller 50 determines that the estimated dryness is outside the predetermined range, the controller 50 executes step S5. In step S5, the controller 50 controls the operating controller 54 to stop the operation of the electric motor 40. Then, the controller 50 executes step S4. In this case, in step S4, the controller 50 determines that the electric motor 40 is stopped and terminates the control of the electric motor 40.

[0055] If a driver of vehicle 100 stops the vehicle air conditioning 101, the control unit 50 stops the operation of the electric motor 40, regardless of which step of steps S1 to S5 in Fig. 5 is currently being executed.

[0056] The advantageous effects according to the present embodiment are explained below. (1) The estimating device 53 of the controller 50 estimates the dryness of the refrigerant to be drawn into the compression section 30 based on the characteristic map stored in the memory 52. ​​That is, the estimating device 53 estimates the dryness of the refrigerant without using the temperature of the refrigerant discharged from the compression section 30. This allows the estimating device 53 to estimate the dryness of the refrigerant to be drawn into the compression section 30 even if the refrigerant contains liquid refrigerant, unlike when the dryness is estimated based on the temperature of the refrigerant discharged from the compression section 30. This allows the scroll compressor 10 to estimate the dryness of the refrigerant being drawn in, even if the discharged refrigerant contains liquid refrigerant.The operating control 54 of the control unit 50 controls the operation of the electric motor 40 according to the estimated dryness. For example, if the estimating device 53 of the control unit 50 estimates a dryness level that could cause the compression section 30 to compress the liquid refrigerant, the operating control 54 of the control unit 50 stops the operation of the electric motor 40. In this way, the scroll compressor 10 avoids malfunctions caused by the compression of the liquid refrigerant. (2) The accuracy of the energy consumption detected by the motor information detector 51 improves over time, from the activation of the electric motor 40 until its operation stabilizes. Since the estimating device 53 estimates the dryness of the refrigerant after the predetermined time has elapsed since the activation of the electric motor 40, it estimates the dryness more accurately than if it were estimated immediately after the activation of the electric motor 40. That is, the control unit 50 of the scroll compressor 10 controls the electric motor 40 more accurately after the predetermined time has elapsed since the activation of the electric motor 40. (3) If the motor information detector 51 detects the energy consumption of the electric motor 40 immediately after the electric motor 40 is switched on, the motor information detector 51 may detect the energy consumption of the electric motor 40 erroneously, and the estimating device 53 of the controller 50 may therefore estimate an abnormal dryness level based on the erroneously detected energy consumption value. However, according to the present embodiment of the controller, the estimating device 53 of the controller 50 estimates the dryness of the refrigerant after the predetermined time has elapsed since the activation of the electric motor 40. This allows the controller 50 to prevent the electric motor 40 from being stopped due to an abnormal dryness level. In other words, the operating controller 54 controls the electric motor 40 in the aforementioned manner, so that the scroll compressor 10 avoids an unintended stoppage of the electric motor 40. (4) In the scroll compressor 10, the operating control 54 can stop the electric motor 40 if the dryness estimated by the estimating device 53 is outside the predetermined range. The predetermined range according to the present embodiment is the acceptable dryness range of the refrigerant compressed by the compression section 30. This allows the scroll compressor 10 to avoid compressing the refrigerant with an undesired dryness. (5) For example, the arrangement of the intake pressure sensor 61 and the exhaust pressure sensor 62 according to the present embodiment enables the intake pressure sensor 61 and the exhaust pressure sensor 62 to detect the intake pressure and the exhaust pressure more accurately than in an arrangement where the

[0057] The intake pressure sensor 61 and the exhaust sensor 62 are located away from the intake port 23c and the exhaust port 25d. (6) The intake pressure sensor 61 and the discharge pressure sensor 62 are included in the scroll compressor 10. This configuration enables the scroll compressor 10 to estimate the dryness of the refrigerant drawn in through the intake port 23c without the refrigerant circuit C, which includes the scroll compressor 10, needing to include another intake pressure sensor 61 and another discharge pressure sensor 62. (7) This configuration eliminates the need for the refrigerant circuit C to include an additional intake pressure sensor 61 and an additional discharge pressure sensor 62, thus enabling miniaturization of the refrigerant circuit C. Accordingly, the scroll compressor 10 according to the present embodiment enables miniaturization of the vehicle air conditioning system 101, which includes the scroll compressor 10.

[0058] The aforementioned embodiments can be modified as described below. The embodiments can be combined with the following modifications within a technically consistent range.

[0059] The scroll compressor 10 is not necessarily attached to the vehicle 100. The scroll compressor 10 is not necessarily included in the vehicle air conditioning system 101. For example, the scroll compressor 10 may be included in a stationary air conditioning system.

[0060] The intake pressure sensor 61 can detect the refrigerant pressure downstream of the intake port 23c and upstream of the compression chamber 30a within the scroll compressor 10. In this configuration, the intake pressure sensor 61 is mounted in a part of the housing 20 upstream of the compression section 30. For example, the intake pressure sensor 61 can detect the refrigerant pressure in the motor chamber 23e.

[0061] The intake pressure sensor 61 is not necessarily located at the intake port 23c. For example, the intake pressure sensor 61 can be located downstream of the evaporator 13 and upstream of the intake port 23c in the refrigerant circuit C. That is, the intake pressure sensor 61 should be located in a position where it can detect the pressure of the refrigerant before the refrigerant is compressed by the compression section 30.

[0062] The discharge pressure sensor 62 can detect the refrigerant pressure upstream of the discharge port 25d and downstream of the compression chamber 30a within the scroll compressor 10. In this configuration, the discharge pressure sensor 62 is mounted in a part of the housing 20 downstream of the compression section 30. For example, the discharge pressure sensor 62 can detect the refrigerant pressure in the discharge chamber 25a.

[0063] The discharge pressure sensor 62 is not necessarily located at the discharge port 25d. For example, the discharge pressure sensor 62 can be located upstream of the condenser 11 and downstream of the discharge port 25d in the refrigerant circuit C. That is, the discharge pressure sensor 62 should be located in a position that allows it to detect the pressure of the refrigerant after the refrigerant has been compressed through the compression section 30.

[0064] The operating control 54 does not necessarily stop the electric motor 40 if the dryness of the refrigerant, as estimated by the estimating device 53, is outside the predetermined range. For example, if the dryness estimated by the estimating device 53 is outside the predetermined range, the operating control 54 can change the speed of the electric motor 40 so that the estimated dryness falls within the predetermined range.

[0065] The estimating device 53 can estimate the dryness immediately after the activation of the electric motor 40.

[0066] The characteristic map can be generated in a different way than in the exemplary embodiment. For example, the characteristic map can be generated by machine learning using the relationship between the intake pressure, exhaust pressure, rotational speed, energy consumption, and dryness, obtained from simulations, as training data.

[0067] The motor information detector 51 is not necessarily connected to the speed sensor. For example, the motor information detector 51 can detect a command value issued by the controller 50.

[0068] The electric compressor is not limited to the scroll compressor 10. For example, the electric compressor can be a centrifugal compressor. In this case, the compression section 30 comprises a variety of impellers and diffuser flow paths. Additional note

[0069] The following describes the technical ideas behind the exemplary implementations and modifications. 1. The electric compressor is attached to a vehicle and included in the vehicle's air conditioning system. 2. The electric compressor comprises a housing for receiving a compression section, an electric motor and a control system, wherein an intake pressure sensor is located in a part of the housing upstream of the compression section and an exhaust pressure sensor is located in a part of the housing downstream of the compression section. 3. The electric compressor includes an estimating device, wherein the estimating device does not estimate the dryness based on the temperature of a refrigerant. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2009-192090

[0002]

Claims

[1] Electric compressor (10) with: a compression section (30) configured to compress a refrigerant; an electric motor (40) configured to drive the compression section (30); and a controller (50) configured to control the electric motor (40), wherein the controller (50) includes a motor information detector (51) configured to detect the speed and energy consumption of the electric motor (40), wherein the controller (50) is connected to an intake pressure sensor (61) for detecting the intake pressure of the refrigerant to be drawn into the compression section (30) and an exhaust pressure sensor (62) for detecting the exhaust pressure of the refrigerant discharged from the compression section (30), wherein the control (50) includes: a storage device (52) for storing a characteristic map that specifies a correspondence between the intake pressure, the discharge pressure, the rotational speed, the energy consumption and a dryness of the refrigerant to be drawn into the compression section (30); an estimation device (53) configured to estimate the dryness of the refrigerant based on the characteristic map using the rotational speed and energy consumption detected by the motor information detector (51), the intake pressure detected by the intake pressure sensor (61), and the discharge pressure detected by the discharge pressure sensor (62); and an operating control (54) which is configured to control the operation of the electric motor (40) according to the dryness estimated by the estimating device (53). [2] Electric compressor (10) according to claim 1, wherein the estimating device (53) estimates the dryness of the refrigerant after a predetermined time has elapsed since the activation of the electric motor (40). [3] Electric compressor (10) according to claim 1 or 2, wherein the operating control (54) stops the electric motor (40) when the dryness estimated by the estimating device (53) is outside a predetermined range. [4] Electric compressor (10) according to claim 1 or 2, wherein the electric compressor (10) comprises a housing (20) for receiving the compression section (30), the electric motor (40) and the control (50), wherein the housing (20) has: an intake port (23c) through which the refrigerant to be compressed by the compression section (30) is drawn into the housing (20); and a discharge port (25d) through which the refrigerant compressed by the compression section (30) is discharged from the housing (20), the intake pressure sensor (61) is attached to the intake port (23c), and the discharge pressure sensor (62) is attached to the discharge port (25d).

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