Scroll-type electric compressor

Abstract

The invention provides a scroll electric compressor which can reduce the pressure in a scroll compression mechanism as soon as possible when a motor is stopped, smoothly and effectively prevent reverse rotation and improve noise. The control device (62) executes: a deceleration control in which, after receiving a stop instruction for the motor (2), the switching element is switched so as to reduce the rotational speed of the motor (2); and a braking control in which, after the rotational speed of the motor (2) is reduced by the deceleration control, the switching elements (66A-66F) are switched so that the rotor (29) of the motor (2) is stopped and fixed at an angle at which the back pressure hole of the movable scroll is not blocked or an angle at which the discharge hole of the fixed scroll is not blocked.

Description

Technical Field

[0001] The present invention relates to a scroll type electric compressor, and more particularly to control for preventing a scroll compression mechanism and a rotor from rotating in reverse. Background Art

[0002] The scroll-type electric compression mechanism is a scroll compression mechanism comprising a fixed scroll member having a spiral wrap on the surface of a mirror plate, and a movable scroll member having a spiral wrap on the surface of the mirror plate. The wraps of each scroll member are opposed to each other, and a compression chamber is formed between the wraps. The movable scroll member is caused to revolve and rotate relative to the fixed scroll member by a motor, so that the volume of the compression chamber is reduced while moving from the outside to the inside, thereby compressing the working fluid (refrigerant).

[0003] In addition, an inverter device is integrally provided in the scroll electric compressor, which includes a three-phase inverter circuit composed of multiple switching elements and a control device. The control device switches the switching elements to convert the DC voltage from a DC power source such as a battery into a three-phase AC voltage and applies it to the motor, thereby driving the motor.

[0004] Furthermore, if a stop instruction of the motor is received from the outside, the control device stops the switching action of the switch element to stop the driving of the motor. At this time, as the working fluid (refrigerant) remaining in the compression chamber expands, the movable scroll (and the rotor of the motor) rotates in the opposite direction due to the pressure difference between the discharge side and the suction side of the scroll compression mechanism, and noise is generated from the scroll compression mechanism. Therefore, a technology has been developed to prevent such reverse rotation by performing brake control using power generation braking when the motor is stopped and fixing the rotor (for example, see Patent Document 1). Prior art literature Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-56322 Summary of the invention Problems to be Solved by the Invention

[0006] Here, Figure 7 The figure shows a cross-sectional view of a movable scroll 100 and a fixed scroll 101 constituting a general scroll compression mechanism. A wrap 103 is formed on the surface of a mirror plate 102 of the movable scroll 100, and a wrap 106 is also formed on the surface of a mirror plate 104 of the fixed scroll 101. A compression chamber 107 is formed between these wraps 103 and 106.

[0007] A back pressure hole 108 is formed in the mirror plate 102 of the movable scroll 100. The back pressure hole 108 is a hole that connects the back pressure chamber 109 on the back side of the mirror plate 102 with the compression chamber 107, and releases the pressure to the compression chamber 107 of the intermediate pressure portion when the pressure (back pressure) of the back pressure chamber 109 is excessive. However, when the motor is stopped, if Figure 7 As shown in the figure, the wrap 106 of the fixed scroll 101 blocks the back pressure hole 108, and the pressure (refrigerant and oil) in the compression chamber 107 cannot be released from the back pressure hole 108 to the back pressure chamber 109, and the pressure release becomes slow. Therefore, when the brake control ends, the pressure remains in the compression chamber 107 of the scroll compression mechanism, and there is a risk of starting reverse rotation and generating noise.

[0008] Therefore, it is also conceivable to extend the time for executing the brake control, but since the switching element is energized for a correspondingly long time, this time there will be problems such as failure due to heat generation of the switching element and shortened life.

[0009] The present invention is made to solve the above-mentioned problems of the prior art, and its object is to provide a scroll type electric compressor which can reduce the pressure inside the scroll compression mechanism as soon as possible when the motor stops, thereby smoothly and effectively preventing reverse rotation and achieving noise improvement. Means for solving problems

[0010] The scroll electric compressor of the present invention is characterized in that it comprises: a scroll compression mechanism, comprising a movable scroll member and a fixed scroll member having a back pressure hole, for compressing a working fluid; a motor, for driving the movable scroll member; an inverter circuit, comprising a plurality of switching elements, for driving the motor; and a control device, for switching the switching elements, the control device performing the following controls: a deceleration control, for switching the switching elements after receiving a stop instruction from the motor to reduce the rotation speed of the motor; and a braking control, for switching the switching elements after reducing the rotation speed of the motor by the deceleration control to stop the rotor of the motor at an angle at which the back pressure hole of the movable scroll member is not blocked or at an angle at which the discharge hole of the fixed scroll member is not blocked and fixed at that angle.

[0011] The scroll electric compressor of the invention of technical solution 2 is characterized in that, in the above invention, the deceleration control performed by the control device includes: sensorless deceleration control, after receiving a stop instruction of the motor, the speed of the motor is reduced by sensorless vector control; and forced reversing deceleration control, after the speed of the motor is reduced by the sensorless deceleration control, the speed of the motor is reduced to a specified low value by forced reversing control.

[0012] The scroll electric compressor of the invention of technical solution 3 is characterized in that, in the above invention, the control device controls the value of the phase current in the forced reversing deceleration control and / or braking control based on the phase current in the sensorless deceleration control or the pressure state of the scroll compression mechanism.

[0013] The scroll electric compressor of the invention of claim 4 is characterized in that, in the invention of claim 1 , the control device performs braking control based on electromagnetic braking before the rotation speed of the motor reaches zero, and in the braking control, the value of the phase current of the motor is feedback controlled.

[0014] The scroll electric compressor of the invention of technical solution 5 is characterized in that, in the above-mentioned inventions, the control device uses the correlation between the phase current and the angle at which the back pressure hole or the discharge hole is not blocked, the predetermined rotor angle and at least one of the sensors for detecting the angle of the rotor to detect the angle at which the back pressure hole or the discharge hole is not blocked.

[0015] The scroll electric compressor of the invention of technical solution 6 is characterized in that, in the inventions of technical solutions 1 to technical solutions 4, the scroll compression mechanism is composed of a fixed scroll member and a movable scroll member having spiral wraps formed on the surfaces of each mirror plate respectively opposed to each other, so that the movable scroll member is caused to perform orbital rotational motion relative to the fixed scroll member, so that the compression chamber formed between the wraps of the two scroll members moves while shrinking from the outside to the inside, thereby compressing the working fluid, the discharge hole connects the discharge chamber on the back side of the mirror plate of the fixed scroll member with the compression chamber, the back pressure hole connects the back pressure chamber on the back side of the mirror plate of the movable scroll member with the compression chamber, and the back pressure hole is not blocked at an angle at which the wrap of the fixed scroll member does not block the back pressure hole of the movable scroll member when the rotor is stopped, and the discharge hole is not blocked at an angle at which the wrap of the movable scroll member does not block the discharge hole of the fixed scroll member when the rotor is stopped. Effects of the Invention

[0016] According to the present invention, the scroll electric compressor comprises: a scroll compression mechanism, comprising a movable scroll member and a fixed scroll member having a back pressure hole, for compressing a working fluid; a motor, for driving the movable scroll member; an inverter circuit, comprising a plurality of switching elements, for driving the motor; and a control device, for switching the switching elements, the control device performing the following control: a deceleration control, in which the switching elements are switched after receiving a stop instruction of the motor to reduce the rotation speed of the motor; and a braking control, in which the switching elements are switched after reducing the rotation speed of the motor by the deceleration control to stop the rotor of the motor at an angle at which the back pressure hole of the movable scroll member is not blocked or at an angle at which the discharge hole of the fixed scroll member is not blocked and is fixed at the angle, so that when the motor stops, the rotor is fixed at an angle at which the back pressure hole of the movable scroll member is not blocked by the wrap plate of the fixed scroll member or at an angle at which the discharge hole of the fixed scroll member is not blocked by the wrap plate of the movable scroll member as in the invention of technical solution 6.

[0017] Thus, the pressure inside the scroll compression mechanism can be released from the back pressure hole of the movable scroll or the discharge hole of the fixed scroll as soon as possible to reduce it. Therefore, the time for executing the braking control can be shortened, so the failure and shortening of the life caused by the heating of the switching element can be suppressed to a minimum, and the reverse rotation of the movable scroll can be effectively prevented, and the improvement of the noise generated by the scroll compression mechanism can be achieved.

[0018] In this case, the deceleration control performed by the control device includes, as in the invention of technical solution 2: sensorless deceleration control, after receiving a stop instruction from the motor, reducing the speed of the motor by sensorless vector control; and forced commutation deceleration control, after reducing the speed of the motor by the sensorless deceleration control, reducing the speed of the motor to a specified low value by forced commutation control, thereby enabling the speed of the motor to be reduced as early as possible by the sensorless deceleration control, and forcibly reducing the speed of the motor by forced commutation deceleration control in an area where position detection becomes difficult.

[0019] In addition, if, as in the invention of technical solution 3, the control device controls the value of the phase current in the forced reversing deceleration control and / or braking control based on the phase current in the sensorless deceleration control or the pressure state of the scroll compression mechanism, then, for example, when the value of the phase current in the sensorless deceleration control is small, the value of the phase current in the forced reversing deceleration control and braking control is also reduced accordingly, or when the residual pressure of the scroll compression mechanism is small, the value of the phase current in the forced reversing deceleration control and braking control is also reduced accordingly, thereby enabling the forced reversing deceleration control and braking control to be performed stably and effectively.

[0020] In addition, if the control device performs braking control before the motor speed reaches zero as in the invention of technical solution 4, the angle at which the rotor is stopped and fixed can be reliably and easily made consistent with the angle at which the back pressure hole of the movable scroll member is not blocked. At this time, by performing electromagnetic braking in the braking control and performing feedback control on the value of the phase current of the motor, it is possible to prevent the jump of the excess phase current caused by the regenerative current that was worried about in the previous power generation braking, and it is also possible to prevent adverse conditions such as failure of the component from happening.

[0021] In addition, as in the invention of claim 5, the angle at which the back pressure hole is not blocked can be detected using the amplitude change of the phase current caused by the torque pulsation, a predetermined rotor angle, and a sensor for detecting the rotor angle.

[0022] In addition, as for the details of the scroll compression mechanism, as in the invention of technical solution 6, it includes a fixed scroll member and a movable scroll member with spiral wraps formed on the surfaces of each mirror plate respectively opposed to each other, so that the movable scroll member revolves and rotates relative to the fixed scroll member, so that the compression chamber formed between the wraps of the two scroll members moves while shrinking from the outside to the inside, thereby compressing the working fluid, the discharge hole connects the discharge chamber on the back side of the mirror plate of the fixed scroll member with the compression chamber, the back pressure hole connects the back pressure chamber on the back side of the mirror plate of the movable scroll member with the compression chamber, the angle at which the back pressure hole is not blocked is the angle at which the wrap of the fixed scroll member does not block the back pressure hole of the movable scroll member as described above when the rotor is stopped, and the angle at which the discharge hole is not blocked is the angle at which the wrap of the movable scroll member does not block the discharge hole of the fixed scroll member when the rotor is stopped. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a longitudinal sectional side view of a scroll type electric compressor according to one embodiment of the present invention. Figure 2 yes Figure 1 Circuit diagram of a scroll electric compressor. Figure 3 Yes Figure 2 A flowchart illustrating the sensorless deceleration control, forced reversing deceleration control and braking control performed by a control device. Figure 4 Yes Figure 2 FIG. 2 is a diagram for explaining changes in the rotation speed of a motor during sensorless deceleration control, forced reversing deceleration control, and braking control executed by a control device. Figure 5 yes Figure 1 An enlarged cross-sectional view of a movable scroll and a fixed scroll in a state where the back pressure hole is not blocked. Figure 6This is a diagram showing changes in the amplitude of the phase current of the motor due to torque pulsation. Figure 7 It is a cross-sectional view of the movable scroll and the fixed scroll in a state where the back pressure hole is blocked. Figure 8 It is a graph showing the peak value and filter value of the phase current. DETAILED DESCRIPTION

[0024] Hereinafter, embodiments of the present invention will be described in detail based on the drawings. Figure 1 It is a longitudinal sectional side view of the scroll type electric compressor 1 according to one embodiment of the present invention.

[0025] (1) Scroll electric compressor 1 The scroll electric compressor 1 of the embodiment is a so-called horizontally mounted inverter-integrated scroll electric compressor, which is used, for example, in a refrigerant circuit of an air-conditioning device for an electric vehicle, and sucks in a refrigerant as a working fluid of the air-conditioning device, compresses the refrigerant and discharges it to a discharge pipe. The scroll electric compressor 1 includes a three-phase motor 2, an inverter device 3 for driving the motor 2 (for operating the motor 2), and a scroll compression mechanism 4 driven by the motor 2.

[0026] The scroll electric compressor 1 of the embodiment comprises: a stator housing 7, on the inside of which a motor 2 and a center housing 6 are housed; an inverter housing 8, which is mounted on an end wall 7A on one end side of the stator housing 7 and on the inside of which an inverter device 3 is housed; and a rear housing 9, which is mounted on the other end side of the stator housing 7.

[0027] The stator housing 7 , the inverter housing 8 , and the rear housing 9 are all made of metal (aluminum in the embodiment), and are integrally joined to form a housing 11 of the scroll type electric compressor 1 of the embodiment.

[0028] A motor chamber 12 for housing the motor 2 is formed in the stator housing 7, and one end face of the motor chamber 12 is substantially closed by an end wall 7A of the stator housing 7. The end wall 7A serves as a partition wall for dividing the motor chamber 12 from an inverter housing 13 described later. The other end face of the motor chamber 12 is open, and after housing the motor 2 through the opening, the center housing 6 is housed. In addition, a sub-bearing 16 is mounted on the inner surface (motor chamber 12 side) of the end wall 7A, and the sub-bearing 16 is used to support one end of the drive shaft 14 of the motor 2 so that it can rotate.

[0029] The center housing 6 is opened on the side opposite to the motor 2 (the other end side), and after accommodating the movable scroll member 22 of the scroll compression mechanism 4, the rear housing 9 to which the fixed scroll member 21 of the scroll compression mechanism 4 is fixed is fixed to the stator housing 7, thereby closing the opening.

[0030] In addition, a through hole 17 is opened in the center housing 6 for the other end of the driving shaft 14 of the motor 2 to pass through, and a main bearing 18 is installed in the center housing 6 on the side of the scroll compression mechanism 4 of the through hole 17. The main bearing 18 supports the other end of the driving shaft 14 on the side of the scroll compression mechanism 4 so that it can rotate.

[0031] The motor 2 is composed of a stator 25 on which a coil is wound and fixed to the inner side of the peripheral wall of the stator housing 7, and a rotor 29 rotating inside the stator 25. Figure 2 ) is converted into a three-phase AC voltage by the inverter device 3, and the rotor 29 is driven to rotate by supplying power to the coil of the stator 25 of the motor 2. In addition, the drive shaft 14 is fixed to the rotor 29.

[0032] In addition, the stator housing 7 is formed with a suction port 20, and the refrigerant sucked from the suction port 20 flows into the center housing 6 after passing through the motor 2 in the stator housing 7, and is sucked into the suction portion 37 outside the scroll compression mechanism 4. Thus, the motor 2 is cooled by the sucked refrigerant. In addition, the following structure is formed: the refrigerant compressed by the scroll compression mechanism 4 is discharged from the discharge chamber 27 described later through the discharge port 30 formed in the rear housing 9 to the discharge piping of the refrigerant circuit (not shown) outside the housing 11.

[0033] The scroll compression mechanism 4 is composed of the fixed scroll 21 and the movable scroll 22. The fixed scroll 21 is integrally provided with a disc-shaped mirror plate 23 and a spiral wrap 24 formed of an involute shape or a curve similar thereto and erected on the surface (one surface) of the mirror plate 23, and is fixed to the rear housing 9 with the surface of the mirror plate 23 on which the wrap 24 is erected being the center housing 6 side.

[0034] A discharge hole 26 is formed at the center of the scroll of the mirror plate 23 of the fixed scroll 21, and the discharge hole 26 is connected to the discharge chamber 27 in the rear housing 9. That is, the discharge hole 26 connects the discharge chamber 27 formed by the back side (the other side) of the mirror plate 23 of the fixed scroll 21 with the compression chamber 34. In the figure, "28" is a discharge valve provided at the opening of the discharge hole 26 on the back side of the mirror plate 23.

[0035] The movable scroll 22 is a scroll that revolves and rotates relative to the fixed scroll 21, and integrally includes a disc-shaped mirror plate 31, a spiral wrap 32 formed by an involute or a curve similar to an involute and uprightly arranged on the surface (one surface) of the mirror plate 31, and a boss 33 protruding from the center of the back side (the other surface) of the mirror plate 31.

[0036] The movable scroll 22 is arranged with the lap 32 protruding toward the fixed scroll 21 , the lap 32 faces and meshes with the lap 24 of the fixed scroll 21 , and a compression chamber 34 is formed between the laps 24 , 32 .

[0037] That is, the wrap 32 of the movable scroll 22 is opposed to the wrap 24 of the fixed scroll 21, and meshes with each other in such a manner that the front end of the wrap 32 contacts the surface of the mirror plate 23, and the front end of the wrap 24 contacts the surface of the mirror plate 31, and an eccentric portion 36 eccentrically provided from the axis at the other end of the drive shaft 14 is fitted into the boss 33 of the movable scroll 22. Furthermore, if the drive shaft 14 rotates together with the rotor 29 of the motor 2, the movable scroll 22 does not rotate on its own, but performs an orbital rotation motion relative to the fixed scroll 21.

[0038] The movable scroll 22 revolves eccentrically relative to the fixed scroll 21, so the eccentric direction and contact position of each wrap 24, 32 move while rotating, and the compression chamber 34 that sucks the refrigerant from the outer suction portion 37 gradually shrinks while moving inward. As a result, the refrigerant is compressed and finally discharged from the central discharge hole 26 to the discharge chamber 27 via the discharge valve 28.

[0039] exist Figure 1 In the figure, "38" is a circular thrust plate. The thrust plate 38 is used to divide the back pressure chamber 39 formed between the back side of the mirror plate 31 of the movable scroll 22 and the center housing 6 and the suction portion 37 on the outside of the scroll compression mechanism 4, and is located on the outside of the boss 33 and sandwiched between the center housing 6 and the movable scroll 22. In addition, "41" is a seal member installed on the back side of the mirror plate 31 of the movable scroll 22 and abutting against the thrust plate 38, and the back pressure chamber 39 and the suction portion 37 are divided by the seal member 41 and the thrust plate 38.

[0040] In addition, "48" is a centrifugal oil separator installed in the discharge chamber 27 of the rear housing 9 (housing 11). The oil separator 48 separates the lubricating oil mixed in the refrigerant discharged from the scroll compression mechanism 4 to the discharge chamber 27 from the refrigerant. The oil separator 48 is formed with an inlet 49, and the refrigerant containing oil flowing in from the inlet 49 rotates in the oil separator 48. The oil is separated by the centrifugal force at this time, and the refrigerant is discharged from the upper end of the outflow port toward the discharge port 30 to the discharge pipe as described above.

[0041] An oil storage chamber 44 is formed in the rear housing 9 below the oil separator 48, and the oil separated from the refrigerant by the oil separator 48 flows into the oil storage chamber 44 from the lower end of the oil separator 48. In the figure, "43" is a back pressure passage formed from the rear housing 9 to the center housing 6. The back pressure passage 43 is a path that connects the oil separator 48 in the discharge chamber 27 (discharge side of the scroll compression mechanism 4) in the rear housing 9 with the back pressure chamber 39, and has a throttle hole 50 in the embodiment. Thus, it is configured that the discharge pressure adjusted by the pressure reduction in the throttle hole 50 of the back pressure passage 43 is supplied to the back pressure chamber 39 together with the oil in the oil storage chamber 44 separated by the oil separator 48.

[0042] The pressure (back pressure) in the back pressure chamber 39 generates a back pressure load that presses the movable scroll 22 toward the fixed scroll 21. The back pressure load overcomes the compression reaction force from the compression chamber 34 of the scroll compression mechanism 4 and presses the movable scroll 22 toward the fixed scroll 21, thereby maintaining the contact between the wrap plates 24, 32 and the mirror plates 31, 23, and compressing the refrigerant in the compression chamber 34.

[0043] In addition, in the embodiment, back pressure holes 5 for connecting the back pressure chamber 39 and the compression chamber 34 are cut and provided at two locations of the mirror plate 31 of the movable scroll member 22. Each back pressure hole 5 serves to release the pressure (refrigerant and oil) from the back pressure chamber 39 to the compression chamber 34 when the pressure (back pressure) in the back pressure chamber 39 is excessive.

[0044] On the other hand, the inverter case 8 includes a case body 10 that internally forms an inverter housing portion 13 that houses the inverter device 3, and a cover member 15 that closes an opening of one end surface of the case body 10. After the inverter device 3 is housed in the inverter housing portion 13, the cover member 15 is mounted on the case body 10.

[0045] A sealing plate 52 is mounted on the end wall 7A (partition wall) of the stator housing 7, and a conductive sealing pin 53 is mounted on the sealing plate 52. One end of the sealing pin 53 penetrates the end wall 7A and enters the motor chamber 12 to be connected to the coil of the stator 25 of the motor 2. The other end of the sealing pin 53 is electrically connected to the circuit board 51 of the inverter device 3 via a press-fit terminal 56.

[0046] (2) Inverter device 3 then, Figure 2 The circuit of the scroll electric compressor 1 including the motor 2 and the inverter device 3 is shown. The inverter device 3 of the embodiment includes a three-phase inverter circuit 61 and a control device 62. The inverter circuit 61 is a circuit that converts the DC voltage of a DC power source (HV battery of a vehicle: for example, HV voltage 300V) 63 into a three-phase AC voltage and applies it to the motor 2.

[0047] The inverter circuit 61 includes a U-phase half-bridge circuit 64U, a V-phase half-bridge circuit 64V, and a W-phase half-bridge circuit 64W, and each phase half-bridge circuit 64U-64W has an upper arm switching element 66A-66C and a lower arm switching element 66D-66F. In addition, each switching element 66A-66F is connected in reverse parallel to a freewheeling diode 67. In the embodiment, each switching element 66A-66F is composed of an insulated gate bipolar transistor (IGBT) or the like in which a MOS structure is assembled in a gate portion.

[0048] The upper end sides of the upper arm switching elements 66A to 66C of the inverter circuit 61 are connected to the upper arm power supply line (positive side bus) 68 of the DC power supply 63. On the other hand, the lower end sides of the lower arm switching elements 66D to 66F of the inverter circuit 61 are connected to the lower arm power supply line (negative side bus) 69 of the DC power supply 63.

[0049] In this case, the upper arm switching element 66A and the lower arm switching element 66D of the U-phase half-bridge circuit 64U are connected in series, the upper arm switching element 66B and the lower arm switching element 66E of the V-phase half-bridge circuit 64V ​​are connected in series, and the upper arm switching element 66C and the lower arm switching element 66F of the W-phase half-bridge circuit 64W are connected in series.

[0050] In addition, the connection point between the upper arm switch element 66A and the lower arm switch element 66D of the U-phase half-bridge circuit 64U is connected to the armature coil of the U-phase of the motor 2, the connection point between the upper arm switch element 66B and the lower arm switch element 66E of the V-phase half-bridge circuit 64V ​​is connected to the armature coil of the V-phase of the motor 2, and the connection point between the upper arm switch element 66C and the lower arm switch element 66F of the W-phase half-bridge circuit 64W is connected to the armature coil of the W-phase of the motor 2.

[0051] In the figure, "71" is a low voltage power supply (LV battery of the vehicle: for example, LV voltage 12V), which is the power supply of the control device 62. In addition, "72" is a current sensor (for example, a shunt resistor), which is connected to the lower arm power supply line 69 and is used to detect the phase current of the motor 2.

[0052] The control device 62 is composed of a microcomputer having a processor, and driving instructions such as a rotation speed command value and a stop instruction are input to the control device 62 from the ECU 60 as the above-mentioned system of the electric vehicle. That is, the control device 62 inputs the rotation speed command value from the ECU 60 and the phase current of the motor 2 based on the current sensor 72, and based on these, outputs a switching instruction to each switching element 66A to 66F of the inverter circuit 61 to control their on / off state. Specifically, the gate voltage applied to the gate electrode of each switching element 66A to 66F is controlled.

[0053] The control device 62 detects the current value (the value of the shunt current) of the lower arm power supply line 69 through the current sensor 72, and calculates and estimates the phase current of each phase UVW based on the current value and the operating state of the motor 2. Then, the control device 62 of the embodiment estimates the position (angle θ) of the rotor 29 based on the current command value obtained from the speed command value of the motor 2 and the estimated phase current, switches the switching elements 66A to 66F of the inverter circuit 61, applies phase voltage to the armature coils of each phase UVW of the motor 2, and drives the rotor 29 to rotate and drive the movable scroll 22 of the scroll compression mechanism 4. In addition, the so-called angle θ in the present invention is set to be, for example, an angle from the electrical angle zero.

[0054] (3) Deceleration control and braking control of the motor 2 by the control device 62 Next, refer to Figure 3 to Figure 6 The deceleration control and the braking control when the control device 62 stops the motor 2 will be described. In this embodiment, the deceleration control of the motor 2 includes the sensorless deceleration control and the forced reversing deceleration control described later.

[0055] That is, in this embodiment, when the control device 62 receives the stop instruction of the motor 2 from the ECU 60 of the electric vehicle, Figure 3 In step S1 , first, the angle θ1 of the rotor 29 (the position of the rotor 29 ) at which the back pressure hole 5 of the movable scroll 22 is not blocked by the wrap 24 of the fixed scroll 21 is calculated.

[0056] exist Figure 5 2 shows a state where the back pressure hole 5 is not blocked. In this state, the two back pressure holes 5 of the movable scroll 22 are offset from the wrap 24 of the fixed scroll 21, and the back pressure holes 5 are not blocked by the wrap 24 of the fixed scroll 21 and are open (fully open), connecting the compression chamber 34 of the intermediate pressure portion with the back pressure chamber 39. The control device 62 calculates the movable scroll 22 to become the Figure 5 The angle θ1 of the rotor 29 is at the position (the position where the back pressure hole 5 is not blocked).

[0057] The method for calculating the angle θ1 of the rotor 29 when the back pressure hole 5 is not blocked is as follows. (i) Calculation based on the change in phase current amplitude caused by torque ripple Figure 6 The figure shows the change in the amplitude of the phase current of the motor 2 caused by the torque pulsation generated by the compression action of the scroll compression mechanism 4. As shown in the figure, the amplitude of the phase current becomes the maximum at the angle of discharging the refrigerant (the discharge valve 28 is open), and the amplitude of the phase current becomes the minimum at the angle of sucking the refrigerant (the discharge valve 28 is closed).

[0058] The correlation between the angle θ1 of the rotor 29 when the back pressure hole 5 is not blocked and the amplitude change of the phase current caused by the torque pulsation (an example of the correlation between the phase current and the angle when the back pressure hole is not blocked) is obtained in advance by experiments and stored in the control device 62. Then, the angle θ1 of the rotor 29 is calculated by the control device 62 based on the amplitude change of the phase current.

[0059] (ii) Calculation based on the maximum and minimum phase currents Alternatively, calculation may be performed based on the correlation between the angles at which the amplitude of the phase current becomes maximum / minimum and the angle θ1 of the rotor 29 at which the back pressure hole 5 is not blocked (another example of the correlation between the phase current and the angle at which the back pressure hole is not blocked).

[0060] (iii) Calculation based on the peak value and filtered value of the phase current Alternatively, calculation may be performed based on the correlation between the angle of intersection of the phase current information and the lagged phase current information after filtering and the angle θ1 of the rotor 29 at which the back pressure hole 5 is not blocked (another example of the correlation between the phase current and the angle at which the back pressure hole is not blocked). In this case, the control device 62 stores in advance Figure 8 The illustrated graph shows a correlation between an angle at which a peak value of a phase current (phase current information) and a filtered value obtained by filtering the phase current (lag phase current information after filtering) intersect and an angle θ1 of the rotor 29 when the back pressure hole 5 is not blocked.

[0061] (3-1) Sensorless deceleration control Next, the control device 62 executes the sensorless deceleration control in step S2. Figure 4 Indicates the change of the rotation speed N of the motor 2. As described above, the control device 62 controls the rotation speed N of the motor 2 by the sensorless vector control in normal operation, but from the moment when the ECU 60 of the electric vehicle receives the stop instruction of the motor 2, the sensorless deceleration control ( Figure 4 In the sensorless deceleration control, the rotational speed N may be reduced continuously at a predetermined reduction rate, or the rotational speed N may be reduced in stages, that is, by repeating deceleration and maintenance (without reducing the rotational speed N).

[0062] Next, the control device 62 Figure 3 In step S3, it is determined whether the rotation speed N of the motor 2 becomes less than a predetermined minimum value, that is, the predetermined rotation speed N1. If it is not less than the predetermined rotation speed N1, the process returns to step S2 and repeats the process. Here, if the rotation speed N of the motor 2 is reduced by the sensorless deceleration control as described above, the position (angle θ) of the rotor 29 cannot be estimated soon.

[0063] (3-2) Forced reversing deceleration control Therefore, when the rotation speed N of the motor 2 is reduced to less than the predetermined rotation speed N1 by the sensorless deceleration control (after the rotation speed N1 is less than the predetermined rotation speed N1), the control device 62 proceeds to step S4 to execute the forced reversing deceleration control ( Figure 4 In the forced commutation deceleration control, the control device 62 determines the rotation speed and performs forced commutation control of forced switching of the switching elements 66A to 66F to reduce the rotation speed N of the motor 2.

[0064] In this forced switching deceleration control, the rotation speed N may be continuously reduced to a predetermined rotation speed N2 described later at a predetermined reduction rate, or the rotation speed N2 may be maintained for a certain period of time after being reduced to the predetermined rotation speed N2.

[0065] Next, the control device 62 Figure 3 In step S5, it is determined whether the rotation speed N of the motor 2 is less than a value smaller than the specified rotation speed N1 and is a value before reaching zero, that is, the specified rotation speed N2 (prescribed low value), and the angle θ of the rotor 29 becomes the angle θ1 calculated in step S1 at which the back pressure hole 5 is not blocked. If this condition is not met, return to step S4 and repeat the process.

[0066] In addition, since it is forced commutation control, the control device 62 itself grasps the rotation speed N of the motor 2. In addition, the angle θ of the rotor 29 can be grasped by adding the angle of the rotor 29 grasped in the forced commutation control to the position (angle) of the rotor 29 estimated in the above-mentioned sensorless vector control.

[0067] In addition, Figure 4 The phase current of the motor 2 is detected in the sensorless deceleration control in the region (A), so in this embodiment, the control device 62 controls the value of the phase current in the forced commutation deceleration control to a required appropriate value based on the phase current in the sensorless deceleration control. That is, the control device 62 estimates the torque based on the value of the phase current in the sensorless deceleration control, and changes the value of the phase current in the forced commutation deceleration control to decrease if the torque is small, and conversely increase the value of the phase current in the forced commutation deceleration control if the torque is large.

[0068] (3-3) Braking control When the rotational speed N of the motor 2 is less than the specified rotational speed N2 and the angle θ of the rotor 29 becomes angle θ1 through the forced reversing deceleration control as described above, that is, when the angle θ of the rotor 29 becomes angle θ1 after the rotational speed N is less than the specified rotational speed N2, the control device 62 proceeds from step S5 to step S6, performs braking control, and fixes the angle θ of the rotor 29 to angle θ1.

[0069] In this braking control, the control device 62 performs electromagnetic braking by turning on each switching element 66A to 66F at a target angle and a target output voltage duty ratio, so that current flows through the motor 2 and the angle θ of the rotor 29 is fixed to an angle θ1 ( Figure 4 In this case, the control device 62 performs feedback control on the value of the phase current of the motor 2 by electromagnetic braking. Here, when there are multiple compression chambers 34 or a single back pressure hole 5 or a group of back pressure holes 5, only the angle θ1 may be changed a predetermined number of times.

[0070] In this embodiment, even in this braking control, the control device 62 controls the value of the phase current to a required appropriate value based on the phase current in the sensorless deceleration control. That is, the control device 62 estimates the torque based on the value of the phase current in the sensorless deceleration control, and changes the value of the phase current in the braking control to decrease if the torque is small, and to increase the value of the phase current in the braking control if the torque is large.

[0071] By such brake control, the angle θ of the rotor 29 of the motor 2 is fixed to the angle θ1, so that the pressure (refrigerant and oil) in the compression chamber 34 of the scroll compression mechanism 4 is released from the back pressure hole 5 to the back pressure chamber 39. Thus, the reverse rotation of the scroll compression mechanism 4 is avoided.

[0072] The control device 62 then determines in step S7 whether a predetermined time t1 has passed since the start of the braking control. If the predetermined time t1 has not passed, the control device 62 returns to step S6 to continue the braking control. If the predetermined time t1 has passed since the start of the braking control, the control device 62 proceeds to step S8 to end the braking control and turn off all the switch elements 66A to 66F.

[0073] According to the present invention described in detail above, the control device 62 performs the following control: deceleration control, after receiving the stop instruction of the motor 2, the switch elements 66A~66F are switched to reduce the rotational speed N of the motor 2; and braking control, after the rotational speed N of the motor 2 is reduced by the deceleration control, the switch elements 66A~66F are switched to stop the rotor 29 of the motor 2 at the angle θ1 at which the back pressure hole of the movable scroll member 22 is not blocked and fixed at the angle θ1, so that when the motor 2 stops, the rotor 29 is fixed at the angle θ1 at which the wrap 24 of the fixed scroll member 21 does not block the back pressure hole 5 of the movable scroll member 22.

[0074] Thus, the pressure inside the scroll compression mechanism 4 can be released from the back pressure hole 5 of the movable scroll 22 as soon as possible to reduce the pressure. Therefore, the time for executing the braking control can be shortened, so the failure and shortening of the life of the switching elements 66A to 66F caused by the heat can be suppressed to a minimum, and the reverse rotation of the movable scroll 22 can be effectively prevented, and the noise generated from the scroll compression mechanism 4 can be improved.

[0075] In this case, in the embodiment, the control device 62 performs in the deceleration control: sensorless deceleration control, after receiving the stop instruction of the motor 2, the rotational speed N of the motor 2 is reduced by sensorless vector control; and forced commutation deceleration control, after the rotational speed N of the motor 2 is reduced by the sensorless deceleration control, the rotational speed N of the motor 2 is reduced to a specified low value by forced commutation control, thereby, the rotational speed N of the motor 2 can be reduced as early as possible by the sensorless deceleration control, and the rotational speed N of the motor 2 can be forcibly reduced by the forced commutation deceleration control in an area where position detection is difficult.

[0076] In addition, in the embodiment, the control device 62 controls the value of the phase current in the forced commutation deceleration control and the braking control based on the phase current in the sensorless deceleration control. Therefore, as described above, when the value of the phase current in the sensorless deceleration control is small, the value of the phase current in the forced commutation deceleration control and the braking control is correspondingly reduced, thereby enabling the forced commutation deceleration control and the braking control to be performed stably and effectively.

[0077] In addition, in the embodiment, the control device 62 performs braking control before the rotation speed N of the motor 2 reaches zero, so that the angle θ at which the rotor 29 is stopped and fixed can be reliably and easily made consistent with the angle θ1 at which the back pressure hole 5 of the movable scroll member 22 is not blocked. At this time, in the embodiment, the value of the phase current of the motor 2 is feedback-controlled by electromagnetic braking, so that the jump of the excessive phase current caused by the regenerative current that is worried about in the power generation braking can be prevented, and the unfavorable situation of the failure of the switching element, etc., can also be prevented before it occurs.

[0078] In the embodiment, the control device 62 calculates the angle θ1 at which the back pressure hole 5 is not blocked in step S1 and detects the angle of the rotor 29 in step S5 to be the calculated angle θ1. However, the angle θ1 may be detected in step S5 as follows without calculating the angle θ1.

[0079] (A) Detection based on a predetermined angle of the rotor 29 The angle θ1 of the rotor 29 when the back pressure hole 5 is not blocked is obtained in advance by experiments, and the control device 62 stores the angle θ1. Then, the angle θ obtained by adding the position of the rotor 29 that can be grasped in the forced commutation control described later to the position of the rotor 29 estimated in the above-mentioned sensorless vector control is made into the angle θ1, and the situation where the angle of the rotor 29 reaches the angle θ1 is detected.

[0080] (B) Detection by a sensor that detects the angle θ (position) of the rotor 29 The angle θ1 of the rotor 29 when the back pressure hole 5 is not blocked is experimentally obtained in advance and stored in the control device 62. A position detection sensor for the rotor 29 is provided and the angle θ1 of the rotor 29 when the back pressure hole 5 is not blocked is detected based on the output of the sensor.

[0081] In step S5, the control device 62 may calculate the angle θ1 in step S1, detect the situation where the angle θ of the rotor 29 becomes the angle θ1 as described above, or detect it using any one of the above methods (A) and (B), or detect it using a combination of them.

[0082] In addition, in the embodiment, the control device 62 stops and fixes the rotor 29 at the angle θ1 at which the back pressure hole 5 is not blocked, but when the discharge valve 28 with a clearance of the discharge hole 26 is used, the angle at which the wrap 32 of the movable scroll 22 does not block the discharge hole 26 located at the center of the scroll of the mirror plate 23 of the fixed scroll 21 can be set to θ1, and the rotor 29 can be stopped and fixed at the angle θ1. Even in this way, the pressure inside the scroll compression mechanism 4 can be released from the discharge hole 28 as early as possible to reduce it.

[0083] In addition, in the embodiment, the control device 62 performs the sensorless deceleration control and the forced commutation deceleration control in the deceleration control, but in the invention of technical solution 1, all the deceleration controls may be set to the forced commutation deceleration control. In addition, in the embodiment, the sensorless deceleration control is switched to the forced commutation deceleration control at the predetermined speed N1, but it is not limited to this, and it may be switched to the forced commutation deceleration control based on the change of the phase current such as the speed N decreases during the sensorless deceleration control, the sensorless vector control becomes difficult, and the phase current increases.

[0084] In addition, in the embodiment, the forced reversing deceleration control is switched to the braking control based on the specified speed N2, but it is not limited to this, and the switch can also be made based on the condition of the residual pressure of the scroll compression mechanism 4. In this case, the speed N of the motor 2 is maintained at the moment when the speed N is reduced to the specified speed N2. If it is maintained at the specified speed N2, the suction pressure of the scroll electric compressor 1 increases, so the motor load torque caused by the suction pressure increases. On the other hand, the discharge pressure of the scroll electric compressor 1 decreases, so the motor load torque caused by the discharge pressure decreases. The above mechanism can also be used to grasp the condition of the residual pressure of the scroll compression mechanism 4 and transfer from the forced reversing deceleration control to the braking control. The pressure information at this time can be set according to the current and the applied voltage information, the pressure sensor information can be obtained from the ECU60 of the electric vehicle, or a sensor can be set in the scroll electric compressor 1 itself, and the information of the sensor can be used.

[0085] In addition, in the embodiment, in both the forced commutation deceleration control and the braking control, the value of the phase current is changed based on the phase current in the sensorless deceleration control, but it can also be performed in only one of the forced commutation deceleration control and the braking control.

[0086] In addition, in the embodiment, the value of the phase current in the forced reversing deceleration control and the braking control is changed based on the phase current in the sensorless deceleration control, but it is not limited to this. The value of the phase current in the forced reversing deceleration control and the braking control may also be changed based on the pressure state (the above-mentioned residual pressure state) of the scroll compression mechanism 4. In this case, for example, when the residual pressure of the scroll compression mechanism 4 is small, the value of the phase current in the forced reversing deceleration control and the braking control is also reduced accordingly.

[0087] In addition, in the embodiment, the present invention is applied to the scroll electric compressor 1 used in the refrigerant circuit of the air conditioning device for the vehicle, but it is not limited to this. The present invention is effective for the scroll electric compressor used in the refrigerant circuit of various refrigeration devices. In addition, in the embodiment, the present invention is applied to the so-called inverter-integrated scroll electric compressor, but it is not limited to this. The present invention can also be applied to a general scroll electric compressor that does not have an inverter integrally. Description of reference numerals:

[0088] 1: scroll electric compressor; 2: motor; 3: inverter device; 4: scroll compression mechanism; 5: back pressure hole; 21: fixed scroll member; 22: movable scroll member; 23, 31: mirror plate; 24, 32: roll plate; 26: discharge hole; 27: discharge chamber; 29: rotor; 34: compression chamber; 61: inverter circuit; 62: control device; 63: DC power supply; 66A~66F: switching element; 72: current sensor.

Claims

1. A scroll electric compressor, characterized in that: have: The scroll compression mechanism includes a movable scroll member having a back pressure hole and a fixed scroll member, and compresses the working fluid; A motor drives the movable scroll member; an inverter circuit having a plurality of switching elements and driving the motor; as well as a control device for switching the switch element, The control device performs the following control: deceleration control, after receiving a stop instruction of the motor, switching the switching element to reduce the rotation speed of the motor; and The braking control switches the switching element after the rotation speed of the motor is reduced by the deceleration control so that the rotor of the motor stops at an angle at which the back pressure hole of the movable scroll part is not blocked or the discharge hole of the fixed scroll part is not blocked and is fixed at this angle.

2. The scroll electric compressor according to claim 1, characterized in that: The deceleration control performed by the control device includes: sensorless deceleration control, after receiving a stop instruction of the motor, reducing the rotation speed of the motor by sensorless vector control; and The forced commutation deceleration control reduces the rotation speed of the motor to a predetermined low value by forced commutation control after the rotation speed of the motor is reduced by the sensorless deceleration control.

3. The scroll electric compressor according to claim 2, characterized in that: The control device controls the value of the phase current in the forced commutation deceleration control and / or the braking control based on the phase current in the sensorless deceleration control or the pressure state of the scroll compression mechanism.

4. The scroll electric compressor according to claim 1, characterized in that: The control device performs the braking control using electromagnetic braking before the rotation speed of the motor reaches zero, and performs feedback control on the value of the phase current of the motor during the braking control.

5. The scroll electric compressor according to any one of claims 1 to 4, characterized in that: The control device detects the angle at which the back pressure hole or the discharge hole is not blocked by using the correlation between the phase current and the angle at which the back pressure hole or the discharge hole is not blocked, the amplitude change of the phase current caused by torque pulsation, the predetermined angle of the rotor and at least one of the sensors for detecting the angle of the rotor.

6. The scroll electric compressor according to any one of claims 1 to 4, characterized in that: The scroll compression mechanism is composed of the fixed scroll member and the movable scroll member, each of which has a spiral wrap formed on each surface of each mirror plate. The movable scroll member is made to orbit and rotate relative to the fixed scroll member, so that the compression chamber formed between the wraps of the two scroll members moves while shrinking from the outside to the inside, thereby compressing the working fluid, the discharge hole connects the discharge chamber on the back side of the mirror plate of the fixed scroll member with the compression chamber, the back pressure hole connects the back pressure chamber on the back side of the mirror plate of the movable scroll member with the compression chamber, and, The angle at which the back pressure hole is not blocked is an angle at which the wrap plate of the fixed scroll does not block the back pressure hole of the movable scroll when the rotor is stopped, and the angle at which the discharge hole is not blocked is an angle at which the wrap plate of the movable scroll does not block the discharge hole of the fixed scroll when the rotor is stopped.

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