KR20170026200A - Motor-driven compressor - Google Patents

Abstract

The present invention relates to an electric compressor capable of stopping reverse rotation of a rotor at an initial stage. The electric compressor includes: a three-phase motor having the rotor; a housing; a compression unit; a driving circuit; and a control unit. The driving circuit includes a U-phase upper arm switching element, a U-phase lower arm switching element, a V-phase upper arm switching element, a V-phase lower arm switching element, a W-phase upper arm switching element, and a W-phase lower arm switching element. The control unit controls speed reduction in response to rotation of the rotor in a direction opposite to the forward direction. The control unit controls the driving circuit in a switching control mode including a first mode and a second mode. One or more switching elements of three-phase upper arm switching element and the three-phase lower arm switching element are in an ON state while the remaining switching element are in an OFF state in the first mode. In a combination of the switching element in the ON state and the switching element in the OFF state, the second mode is different from the first mode.

Description

[0001] MOTOR-DRIVEN COMPRESSOR [0002]

The present invention relates to an electric compressor.

For example, Japanese Unexamined Patent Publication (Kokai) No. 2003-120555 discloses a compressor having a compressor having a movable scroll capable of orbital motion with respect to fixed scroll and fixed scroll, and an electric compressor having an electric motor for revolving the movable scroll Lt; / RTI > The motor-driven compressor has a compression chamber partitioned by the fixed scroll and the movable scroll, in which the suction fluid is sucked, and the movable scroll performs idle motion to compress the suction fluid in the compression chamber and to discharge the compressed fluid.

Japanese Unexamined Patent Application Publication No. 2003-120555 discloses an air compressor in which an injection port for introducing an intermediate pressure fluid of a higher pressure than a suction fluid is formed in a compression chamber and an air conditioner having the electric compressor. The air conditioning apparatus includes, for example, an injection pipe connected to an injection port and a gas-liquid separator connected to an injection pipe. The intermediate-pressure fluid separated by the gas-liquid separator flows into the compression chamber through the injection pipe and the injection port, thereby increasing the flow rate of the fluid flowing into the compression chamber.

In the configuration in which the intermediate-pressure fluid as described above is introduced into the compression chamber, the intermediate-pressure fluid remaining in the injection pipe sometimes flows into the compression chamber through the injection port at the time of stopping the operation of the electric compressor. In this case, the movable scroll may revolve in the opposite direction to the forward direction, and the rotor may also rotate in the reverse direction.

Here, for example, when starting the electric compressor, if the reverse rotation phenomenon occurs, it can be considered to wait until the reverse rotation of the rotor stops. However, in a configuration in which the rotor is kept waiting until the reverse rotation is stopped, the period required for starting the motor-driven compressor tends to be long, so that the responsiveness may be lowered.

An object of the present invention is to provide an electric compressor capable of stopping the reverse rotation of the rotor prematurely.

A motor compressor for achieving the above object comprises a housing having a three-phase motor having a rotor and a suction port for sucking fluid, and a motor driven by the three-phase motor for compressing the sucked fluid, which is the fluid sucked from the suction port And a control section for controlling the driving circuit. The motor-driven compressor according to claim 1, further comprising: a compression section for discharging the compressed fluid as the suction fluid compressed; a drive circuit for driving the three-phase motor; A fixed scroll fixed to the fixed scroll, a movable scroll engaged with the fixed scroll and configured to revolve with respect to the fixed scroll, and a compression chamber partitioned by the fixed scroll and the movable scroll, The movable scroll is revolved in the forward direction, and accordingly, And an injection port for introducing an intermediate-pressure fluid, which is higher in pressure than the suction fluid and lower in pressure than the compressed fluid, into the compression chamber, Phase and cuboid switch elements connected to each other, a v-phase and two-phase arm switching elements connected to each other, a v-phase and two-phase arm switching element connected to each other, Wherein the control unit is configured to perform deceleration control for decelerating the rotor in response to the rotor being rotated in a direction opposite to the forward direction, and the control unit, in the deceleration control, One or a plurality of switching elements of the three-phase arm switching element and the three-phase low arm switching element are turned ON, The driving circuit is controlled in a switching control mode in which the first aspect in which the switching device is in the OFF state and the second aspect in which the combination of the switching device to be in the ON state and the switching device in the OFF state is different from the first aspect .

1 is a schematic cross-sectional view of an electric compressor.
2 is a cross-sectional view of a compression unit included in the motor-driven compressor of FIG.
3 is a schematic view of a vehicle air conditioning apparatus.
4 is a circuit diagram showing the electrical configuration of the inverter.
Fig. 5 is a time chart of the lower arm switching element in the one-phase pattern, in which (a) shows ON / OFF of the u-phase lower arm switching element, (C) shows ON / OFF of the w-phase lower arm switching element.
6 is a graph schematically showing each phase current when the rotor is rotating in the forward direction.
7 is a graph schematically showing each phase current when the rotor is rotating in a direction opposite to the forward direction.
8 is a flowchart showing the reverse rotation control process.
9 is a diagram showing the switching pattern and the duty ratio in each deceleration control.
Fig. 10 is a time chart of the lower arm switching element in the two-phase pattern, in which (a) shows ON / OFF of the u-phase lower arm switching element, (C) shows ON / OFF of the w-phase lower arm switching element.
11 is a graph showing the change over time of the number of rotations of the rotor during deceleration control.

Hereinafter, an embodiment of the electric compressor will be described.

As shown in Fig. 1, the motor-driven compressor 10 includes a housing 11 having a suction port 11a through which fluid is sucked and a discharge port 11b through which fluid is discharged. The housing 11 is generally cylindrical in shape. Specifically, the housing 11 has a first part 12 and a second part 13, and each has a cylindrical shape having a bottom part and an opening end. The first part 12 and the second part 13 are installed so that their opening ends are in contact with each other. The suction port 11a is formed in the vicinity of the side wall portion 12a of the first part 12 and more particularly the bottom part 12b of the first part 12 of the side wall part 12a. The discharge port 11b is formed in the bottom portion 13a of the second part 13.

The motor-driven compressor 10 includes a rotary shaft 14, a compression unit 15 that compresses the fluid sucked from the suction port 11a, that is, the suction fluid, and discharges the compressed fluid from the discharge port 11b, And a motor (16). The rotary shaft 14, the compression section 15, and the electric motor 16 are accommodated in the housing 11. The electric motor 16 is disposed in the housing 11 on the side corresponding to the suction port 11a and the compressed portion 15 is disposed on the side corresponding to the discharge port 11b in the housing 11 have.

The rotary shaft (14) is accommodated in the housing (11) in a rotatable state. Specifically, a shaft supporting member 21 for axially supporting the rotary shaft 14 is formed in the housing 11. As shown in Fig. The shaft support member 21 is fixed to the housing 11 at a position between the compression section 15 and the electric motor 16, for example. The shaft support member 21 is formed with a through hole 23 through which the rotation shaft 14 can be inserted and in which the first bearing 22 is formed. The shaft supporting member 21 and the bottom portion 12b of the first part 12 are opposed to each other and a cylindrical boss 24 protrudes from the bottom portion 12b. A second bearing (25) is formed on the inner side of the boss (24). The rotary shaft 14 is rotatably supported by the first bearing 22 and the second bearing 25.

The compression section 15 includes a fixed scroll 31 fixed to the housing 11 and a movable scroll 32 capable of idle movement relative to the fixed scroll 31.

The fixed scroll 31 has a disk-like fixed substrate 31a formed on the same axis as the rotating shaft 14 and a fixed vortex wall 31b rising from the fixed substrate 31a. Likewise, the movable scroll 32 is provided with a movable substrate 32a on a disk and opposed to the fixed substrate 31a, and a movable swirl wall 32b rising from the movable substrate 32a toward the fixed substrate 31a have.

As shown in Figs. 1 and 2, the fixed scroll 31 and the movable scroll 32 are engaged with each other. More specifically, the stationary swirl wall 31b and the movable swirl wall 32b are engaged with each other. The distal end surface of the stationary swirl wall 31b contacts the movable substrate 32a, and the movable swirl wall 32b, Is in contact with the fixed substrate 31a. The compression chamber (33) is partitioned by the fixed scroll (31) and the movable scroll (32). 1, the shaft support member 21 is provided with a suction passage 34 for sucking the suction fluid into the compression chamber 33. [

The movable scroll (32) is configured to revolve along with the rotation of the rotary shaft (14). A part of the rotary shaft 14 is protruded toward the compression portion 15 via the insertion hole 23 of the shaft supporting member 21. [ An eccentric shaft 35 is formed at an eccentric position with respect to the axis L of the rotary shaft 14 in the section of the rotary shaft 14 opposed to the compression section 15. A bush 36 is formed on the eccentric shaft 35. The bush 36 and the movable scroll 32 (more specifically, the movable base plate 32a) are connected via a bearing 37.

The motor-driven compressor 10 is provided with a rotation restricting portion 38 for restricting the rotation of the movable scroll 32 while allowing the revolving movement of the movable scroll 32. A plurality of rotation restricting portions 38 are formed.

According to this configuration, when the rotary shaft 14 rotates in the predetermined forward direction, the orbiting motion of the movable scroll 32 in the forward direction is performed. Specifically, the movable scroll 32 revolves in the forward direction around the axis of the fixed scroll 31 (i.e., the axis L of the rotary shaft 14). As a result, the volume of the compression chamber (33) decreases, so that the suction fluid sucked into the compression chamber (33) through the suction passage (34) is compressed. The compressed suction fluid, that is, the compressed fluid is discharged from the discharge port 41 formed in the fixed substrate 31a, and then discharged from the discharge port 11b. The forward direction is also referred to as a direction in which the compression of the fluid is normally performed.

1, a discharge valve 42 for covering the discharge port 41 is formed on the fixed substrate 31a. The compressed fluid compressed in the compression chamber (33) is discharged from the discharge port (41) by pushing down the discharge valve (42).

As shown in Figs. 1 and 2, an injection port 43 is formed in the fixed substrate 31a, separately from the discharge port 41. As shown in Fig. A plurality of injection ports 43 are formed, for example, two in detail. The injection port 43 is disposed radially outward of the discharge port 41 in the fixed substrate 31a. An injection pipe 119 is connected to the injection port 43. The connection destination of the injection pipe 119 will be described later.

The electric motor 16 rotates the rotary shaft 14 so that the movable scroll 32 revolves. As shown in Fig. 1, the electric motor 16 includes a rotor 51 that rotates integrally with the rotating shaft 14, and a stator 52 that surrounds the rotor 51. As shown in Fig. The rotor 51 is connected to the rotating shaft 14. A permanent magnet (not shown) is formed in the rotor 51. The stator 52 is fixed to the inner peripheral surface of the housing 11 (specifically, the first part 12). The stator 52 has a stator core 53 opposed to the normal rotor 51 in the radial direction and a coil 54 wound around the stator core 53.

The electric compressor (10) is provided with an inverter (55) as a drive circuit for driving the electric motor (16). The inverter 55 is accommodated in a housing 11, specifically a cylindrical cover member 56 mounted on a bottom portion 12b of the first part 12. The inverter 55 and the coil 54 are electrically connected.

Here, in the present embodiment, the electric compressor 10 is mounted on a vehicle and used in the vehicle air conditioning system 100. That is, in this embodiment, the fluid compressed by the electric compressor 10 is a refrigerant. The vehicle air conditioning system 100 will be described in detail below.

3, the vehicle air conditioning system 100 includes a pipe switching valve 101, a first heat exchanger 102, a second heat exchanger 103, a first expansion valve 104, a second expansion valve 104, (105) and a gas-liquid separator (106).

The pipe switching valve 101 has a plurality of inlets 101a to 101d. The pipe switching valve 101 is connected to the first state in which the first inlet 101a communicates with the second inlet 101b and the third inlet 101c and the fourth inlet 101d communicate with each other, The first inlet 101a and the third inlet 101c communicate with each other and the second inlet 101b and the fourth inlet 101d communicate with each other.

The vehicle air conditioning system 100 includes a first pipe 111 for connecting the first inlet 101a and the discharge port 11b of the motor compressor 10 and a second pipe 111 for connecting the second inlet 101b and the first heat exchanger 102, And a third pipe 113 connecting the first heat exchanger 102 and the first expansion valve 104. The second pipe 112 connects the first heat exchanger 102 and the first expansion valve 104 to each other. The vehicle air conditioning system 100 includes a fourth pipe 114 connecting the first expansion valve 104 and the gas-liquid separator 106, and a fourth pipe 114 connecting the gas-liquid separator 106 and the second expansion valve 105, A sixth pipe 116 connecting the second expansion valve 105 and the second heat exchanger 103 to the pipe 115 and a sixth pipe 116 connecting the second heat exchanger 103 and the third inlet 101c 7 pipe (117). The vehicle air conditioning system 100 further includes an eighth pipe 118 connecting the fourth inlet 101d and the inlet 11a of the motor-driven compressor 10.

In this configuration, the injection pipe 119 connected to the injection port 43 is connected to the gas-liquid separator 106. On the injection pipe 119, a check valve 120 is formed.

The vehicle air conditioning system 100 of the present embodiment is capable of both cooling operation and heating operation. Specifically, the vehicle air conditioning system 100 is provided with an air conditioning ECU 121 that controls the entire vehicle air conditioning system 100 including the pipe changeover valve 101. The air conditioning ECU 121 sets the pipe switching valve 101 to the first state, for example, during the cooling operation. In this case, the refrigerant discharged from the discharge port 11b flows into the first heat exchanger 102 and is condensed by heat exchange with the outside air in the first heat exchanger 102. [ The condensed refrigerant is decompressed in the first expansion valve 104 and flows to the gas-liquid separator 106. Then, it is separated into liquid and gas in the gas-liquid separator 106. The liquid refrigerant is depressurized by the second expansion valve 105 and flows to the second heat exchanger 103. Then, the liquid refrigerant is evaporated by heat exchange with the air in the car by the second heat exchanger 103, and as a result, the air in the car is cooled. The refrigerant evaporated in the second heat exchanger (103) flows toward the suction port (11a) of the electric compressor (10). During the cooling operation, the check valve 120 is in a closed state.

On the other hand, the air conditioning ECU 121 sets the pipe switching valve 101 to the second state, for example, during the heating operation. In this case, the refrigerant discharged from the discharge port 11b flows into the second heat exchanger 103 and is condensed by heat exchange with the air in the second heat exchanger 103. As a result, The air is heated. The refrigerant condensed in the second heat exchanger 103 is decompressed by the second expansion valve 105, flows into the gas-liquid separator 106, and is separated into liquid and gas in the gas-liquid separator 106. The refrigerant in the separated liquid is decompressed in the first expansion valve 104, flows in the first heat exchanger 102, and is evaporated by heat exchange with the outside air in the first heat exchanger 102. Then, the evaporated refrigerant flows into the suction port 11a.

Here, the check valve 120 is in the open state during the heating operation. Thereby, the refrigerant of the gas separated by the gas-liquid separator 106 flows into the compression chamber 33 through the injection pipe 119 and the injection port 43. This increases the flow rate of the refrigerant flowing into the compression chamber (33).

The pressure of the refrigerant of the gas separated by the gas-liquid separator 106, that is, the refrigerant introduced into the compression chamber 33 through the injection port 43 is higher than the pressure of the refrigerant sucked from the suction port 11a, Is lower than the pressure of the refrigerant discharged from the discharge port (11b). The refrigerant sucked from the suction port 11a is referred to as suction refrigerant and the refrigerant discharged from the discharge port 11b is referred to as compressed refrigerant and introduced into the compression chamber 33 from the injection port 43. In the following description, Is referred to as an intermediate-pressure refrigerant. The suction refrigerant corresponds to the "suction fluid", and the compressed refrigerant corresponds to the "compressed fluid".

In the vehicular air conditioning system 100 configured as described above, after the operation of the motor-driven compressor 10 is stopped, the intermediate-pressure refrigerant remaining in the injection pipe 119 flows into the compression chamber 33, ) Rotates in the direction opposite to the normal direction, and as a result, the reverse rotation phenomenon in which the rotor 51 rotates in the direction opposite to the forward direction may occur.

On the other hand, the motor-driven compressor 10 of the present embodiment has a configuration for stopping the reverse rotation phenomenon prematurely. This configuration will be described together with the electrical configuration of the coil 54 of the electric motor 16 and the inverter 55. Fig.

4, the coil 54 includes, for example, a u-phase coil 54u, a v-phase coil 54v, and a w- Phase structure having a phase coil 54w. That is, the electric motor 16 is a three-phase motor. Each of the phase coils 54u, 54v, and 54w is, for example, Y-connected.

The inverter 55 includes a u-phase and iv-phase arm switching element Qu1 and a u-phase and lower arm switching element Qu2 corresponding to the u-phase coil 54u. Similarly, the inverter 55 includes the v-phase and i -amp arm switching device Qv1 and the v-phase and lower arm switching device Qv2 corresponding to the v-phase coil 54v and the w-phase corresponding to the w-phase coil 54w And includes an ivory arm switching element Qw1 and a w-phase and a lower arm switching element Qw2. In short, the inverter 55 is a so-called three-phase inverter.

Each of the switching elements Qu1, Qu2, Qv1, Qv2, Qw1, Qw2 is composed of, for example, an IGBT. However, the present invention is not limited to this, and may be a power type MOSFET or the like.

The inverter 55 has two power lines EL1 and EL2 connected to a DC power supply E mounted on the vehicle. The inverter 55 further includes an u-phase wiring ELu connected to the positive power lines EL1 and EL2 and also having the two switching elements Qu1 and Qu2 on the u-phase. The positive switching elements Qu1 and Qu2 on the u-phase are connected in series to each other via the u-phase wiring ELu, and the connection portions of the switching elements Qu1 and Qu2 of the u- and a u-phase coil 54u are connected. The DC power source E is, for example, a storage device such as a battery or an electric double layer capacitor.

Similarly, the inverter 55 is provided with a v-phase wiring ELv connected to both power lines EL1, EL2 and also having both switching elements Qv1, Qv2 on the v-phase. the connection portion of the v-phase switching elements Qv1 and Qv2 in the v-phase wiring ELv is connected to the v-phase coil 54v. The inverter 55 is provided with a w-phase wiring ELw connected to both power lines EL1 and EL2 and further including w-phase switching elements Qw1 and Qw2. the connection portion of the w-phase switching elements Qw1 and Qw2 in the w-phase wiring ELw is connected to the w-phase coil 54w.

The inverter 55 also has a smoothing capacitor C1 connected in parallel to the DC power supply E. The inverter 55 also has reflux diodes Du1 to Dw2 connected in parallel to the switching elements Qu1 to Qw2. The reflux diodes Du1 to Dw2 may be parasitic diodes of the switching elements Qu1 to Qw2 or may be formed separately from the switching elements Qu1 to Qw2.

The motor-driven compressor 10 is provided with a control device 60 as a control unit for controlling the inverter 55 (more specifically, the switching operation of each of the switching devices Qu1 to Qw2). The control device 60 is connected to the gates of the switching elements Qu1 to Qw2. The control device 60 can be realized by, for example, one or more dedicated hardware circuits and / or one or more processors (control circuits) operating in accordance with a computer program (software). The processor includes a CPU and a memory such as a RAM and a ROM, and the memory stores program codes or commands configured to cause the processor to execute the processing shown in Fig. 8, for example. The memory, or computer readable medium, includes all available media that can be accessed by a general purpose or dedicated computer.

The control device 60 performs PWM control of the inverter 55. [ Specifically, the control device 60 generates a control signal by using a carrier signal (carrier signal) and a command voltage value signal (comparison object signal). The control device 60 periodically applies a voltage having a predetermined pulse width DELTA T to each of the switching elements Qu1 to Qw2 using the generated control signal so that each of the switching elements Qu1 to Qw2 Is periodically turned on / off to convert the DC power from the DC power supply E into AC power. Then, the alternating-current power is input to the electric motor 16, whereby the electric motor 16 is driven, that is, rotated. The control device 60 is configured to be capable of changing the pulse width DELTA T of the switching elements Qu1 to Qw2, that is, the duty ratio D of ON / OFF.

The control device 60 is configured to be able to grasp the phase currents Iu, Iv, and Iw flowing in the phase coils 54u, 54v, and 54w as a current flowing in the electric motor 16. [ Specifically, as shown in Fig. 4, the inverter 55 is formed with current sensors 61 to 63 as current detecting portions for detecting the current flowing through the upper wirings (ELu to ELw). The current sensors 61 to 63 are formed between the lower arm switching elements Qu2 to Qw2 and the second power line EL2 in the upper wires ELu to ELw, for example. The current sensors 61 to 63 transmit the detection results to the control device 60. [ Based on the detection results of the current sensors 61 to 63, the control device 60 determines whether or not the u-phase current Iu, which is the current flowing in the u-phase coil 54u, The phase current Iv and the w-phase current Iw that is the current flowing in the w-phase coil 54w can be grasped.

The specific configuration of the current sensors 61 to 63 is arbitrary, but it is possible to consider, for example, a configuration having a shunt resistor and estimating the phase currents Iu to Iw from the voltage applied to the shunt resistor.

The control device 60 and the air conditioner ECU 121 are electrically connected, and information can be exchanged with each other. The control device 60 starts or stops the operation of the electric compressor 10 in accordance with a request from the air conditioning ECU 121, a result of the abnormality determination, or the like. The operation stop of the electric compressor 10 is to stop the supply of AC power to the electric motor 16 and more specifically to turn off all of the switching elements Qu1 to Qw2.

Here, the control device 60 of the present embodiment is configured such that, after a predetermined waiting period has elapsed after the operation of the motor-driven compressor 10 has been stopped, based on the detection results of the current sensors 61 to 63, And the rotational speed R, that is, the rotational speed of the vehicle. And the control device 60 that executes the holding process corresponds to the " holding portion ".

Specifically, the control device 60 keeps all the ivory arm switching elements Qu1, Qv1, and Qw1, which are the switching elements on the side not corresponding to the current sensors 61 to 63, in the OFF state. The control device 60 periodically turns ON / OFF the switching elements Qu2, Qv2, and Qw2, which are the switching elements on the side corresponding to the current sensors 61 to 63, with a predetermined switching pattern . In the present embodiment, each of the lower arm switching elements Qu2, Qv2 and Qw2 is subjected to a switching operation (that is, ON / OFF operation) and corresponds to a "three-phase target arm switching element".

For example, the control device 60 is a switching pattern in which the three-phase low-arm switching elements Qu2, Qv2 and Qw2 are turned ON in a predetermined order in a predetermined order, and when the one- (Hereinafter, referred to as a one-phase pattern) including a mode in which the lower-phase switching elements of the other two phases are turned OFF, thereby controlling the respective lower-arm switching elements Qu2, Qv2 and Qw2. In the present embodiment, as shown in Figs. 5A to 5C, in the one-phase pattern, the lower arm switching element to be turned ON is switched from the u-phase lower arm switching element Qu2 to the v- And the switching element Qv2 is switched in the order of the w-phase upper and lower arm switching elements Qw2.

For example, a combination mode of Qu2: ON and also of Qu1, Qv1, Qw1, Qv2 and Qw2: OFF is referred to as a first mode, and a combination mode of Qv2: ON and also Qu1, Qv1, Qw1, Qu2, . In this case, the control device 60 may be switched from the first mode to the second mode by periodically turning on / off each of the lower arm switching devices Qu2, Qv2, and Qw2. In other words, the switching mode in the deceleration control (one-phase pattern) includes the first mode and the second mode in which ON / OFF combinations of the switching elements Qu1 to Qw2 are different.

The one-phase pattern is a switching pattern set so that no lower-arm switching elements of a plurality of phases (two-phase or three-phase) among the three-phase low-arm switching elements Qu2, Qv2 and Qw2 are turned ON at the same time.

5A to 5C, the one-phase pattern is not limited to a switching pattern in which any one of the lower-arm switching elements is always in an ON-state, but all the lower-arm switching elements Qu2, Qv2, and Qw2 may be in the OFF state. For example, in the one-phase pattern, the lower arm switching elements are turned ON one by one in a predetermined order via the interval period, and when the one-phase lower arm switching element is ON, the other two- Or a switching pattern in which the device is in an OFF state.

Here, in the present embodiment, the timing at which each of the lower arm switching elements Qu2, Qv2, and Qw2 occurs in the ON state is different by a predetermined period? A. More specifically, during the period from the time when the lower arm switching device Qu2 occurs to the time when the lower arm switching device Qv2 occurs, and when the lower arm switching device Qw2 occurs from when the lower arm switching device Qv2 occurs And the period from when the lower arm switching element Qw2 takes place to when the lower arm switching element Qu2 occurs is the same predetermined period delta a. In this configuration, the one-phase pattern is a switching pattern in which the pulse width? T is set to be equal to or smaller than the predetermined period? A. When the pulse width DELTA T is less than the predetermined period delta a, the one-phase pattern is switched to the ON state by one phase in the predetermined order through the interval period (three-phase OFF period) . When the pulse width DELTA T is equal to the predetermined period DELTA a, the one-phase pattern becomes a switching pattern in which the lower-arm switching elements are turned ON one by one in a predetermined order without interposing an interval period.

Here, the relationship between the rotational direction and the number of rotations R of the rotor 51 and the phase currents Iu, Iv, and Iw will be described with reference to Figs. 6 and 7. Fig.

6 is a graph schematically showing the phase currents Iu, Iv and Iw detected when the rotor 51 rotates in the forward direction. Fig. 7 is a graph showing the relationship between the phase currents Iu, Iv and Iw when the rotor 51 rotates in the reverse direction (Iu, Iv, Iw) detected in the presence of the phase currents Iu, Iv, Iw. 6 and 7, the period of the minimum unit waveform (one triangular wave) of each of the phase currents Iu, Iv, and Iw is longer than the actual period.

6 and 7 show the current waveforms of the phase currents Iu, Iv and Iw when the lower arm switching elements Qu2, Qv2 and Qw2 are always turned on / off. Therefore, when each of the lower arm switching elements Qu2, Qv2 and Qw2 is actually switched in the one-phase pattern, the triangular wave signals Iu, Iv and Iw formed by the phase currents Iu, Iv and Iw shown in Figs. A triangular wave having a number of 1/3 of the number is obtained.

As shown in Figs. 6 and 7, the phase currents Iu, Iv, and Iw (specifically, the envelopes of the respective phase currents Iu, Iv, and Iw) have different phases from each other. For this reason, the phase current having a positive value transits sequentially with the lapse of time. The reason why the phase current becomes a positive value is that the back electromotive force generated in the phase coil corresponding to the phase current becomes lower than the back electromotive force generated in the other phase coil.

Here, the order in which the phase current to be a positive value transits is different between the case where the rotor 51 rotates in the forward direction and the case where the rotor 51 rotates in the reverse direction. Specifically, as shown in Fig. 6, when the rotor 51 is rotating in the forward direction, the phase current that becomes a positive value is the u-phase current Iu - > the v-phase current Iv- > ). On the other hand, as shown in Fig. 7, when the rotor 51 is rotating in the reverse direction, the phase current which becomes the positive value is the sum of the w-phase current Iw - > Transition in order.

The constant current period Ta in which the phase current becomes the positive value corresponds to 1/3 of one period of the electric angle of the rotor 51. [

The control device 60 calculates the current waveform based on the current waveforms obtained from the detection results of the respective current sensors 61 to 63 when the characteristics and the respective lower arm switching elements Qu2, Qv2 and Qw2 are switched in the one- , The rotational direction and the number of rotations (R) of the rotor (51).

In detail, when each of the lower arm switching elements Qu2, Qv2 and Qw2 switches in a one-phase pattern, the current waveforms of the respective phase currents Iu, Iv and Iw corresponding to the current rotational direction and the rotational speed R . The control device 60 grasps the transition order of the phase current that is a positive value from these current waveforms and determines whether the rotation direction of the rotor 51 is the forward direction or the reverse direction based on the detection result.

The control device 60 grasps the constant current period Ta from the current waveform obtained by the switching of the one-phase pattern and calculates the rotation number R of the rotor 51 based on the detected constant current period Ta .

For reference, these characteristics, specifically, the order in which the phase currents which are positive values are changed in accordance with the rotational direction and the points where the constant current period Ta corresponds to 1/3 of one period of the rotor 51 Do not vary according to the switching patterns of the respective lower arm switching elements Qu2, Qv2, Qw2. Therefore, even when the switching pattern of each of the lower arm switching elements Qu2, Qv2, Qw2 is a two-phase pattern, the control device 60 can obtain the above characteristics and the current waveforms obtained from the current sensors 61 to 63 The rotational direction and the number of rotations R of the rotor 51 can be grasped. Details of the two-phase pattern will be described later.

The control device 60 performs the reverse rotation control processing for decelerating and stopping the rotor 51 earlier than the natural deceleration stop based on the determination that the rotor 51 is rotating in the reverse direction by the above holding processing . This reverse rotation control processing will be described.

As shown in Fig. 8, the control device 60 first grasps the number of rotations R of the rotor 51 in step S101. Specifically, when the process of the step S101 is the first time, the control device 60 grasps the number of rotations (R) of the rotor 51 that is grasped in the grasping process that has become the execution time of the reverse rotation control process do. On the other hand, in the processing of the second and subsequent steps S101, on the other hand, the control device 60 determines whether or not the current sensors 61 to 63 are detected based on the detection results of the current sensors 61 to 63 obtained in the deceleration control executed in any of the processes of steps S103, S105, S107, To derive the number of rotations (R).

Thereafter, the control device 60 executes deceleration control in steps S102 to S109 when the number of rotations R detected in step S101 is relatively high (specifically, when it is equal to or greater than the fourth threshold value Rth4) . In the deceleration control, the control device 60 decelerates the rotor 51 by turning ON at least one switching element among the switching elements Qu1 to Qw2. In the present embodiment, in the deceleration control, the control device 60 periodically turns on / off each of the lower arm switching elements Qu2, Qv2, Qw2 with a predetermined switching pattern, and turns on the lower arm switching element And switches sequentially. That is, the switching control mode of the control device 60 in the deceleration control is such that the switching of the lower arm switching elements Qu2, Qv2, Qw2 to the ON / OFF switching states of the lower arm switching elements sequentially Operation). The reason that the lower arm switching elements to be turned ON sequentially is that the ON / OFF combination of the switching elements Qu1 to Qw2 (specifically, each of the lower arm switching elements Qu2, Qv2 and Qw2) It means change.

In this case, the switching frequencies of the lower arm switching elements Qu2, Qv2 and Qw2 are set equal to each other. The switching frequency of each of the lower arm switching elements Qu2, Qv2 and Qw2 is arbitrary as long as it is sufficiently higher than the maximum value of the number of rotations R of the rotor 51 assumed when the refrigerant reversely rotates by the intermediate-pressure refrigerant.

According to this configuration, when the phase current corresponding to the lower arm switching element in the ON state is fixed, heat is generated in the phase coil corresponding to the lower arm switching element in the ON state. Therefore, the kinetic energy of the rotor 51 is converted into thermal energy, and the rotor 51 decelerates. In the following description, the effect that the kinetic energy of the rotor 51 is converted into thermal energy and the rotor 51 is decelerated is referred to as a brake effect.

The phase currents and phase coils corresponding to the lower arm switching elements that are turned on mean that the u-phase current Iu and the u-phase coil 54u are in the ON state when the u-phase lower arm switching device Qu2 is in the ON state it means. Similarly, when the v-phase lower arm switching device Qv2 is in the ON state, it means the v-phase current Iv and the v-phase coil 54v, and when the w-phase lower arm switching device Qw2 is in the ON state w-phase current Iw and w-phase coil 54w.

In this case, the higher the respective phase currents Iu, Iv, Iw, the more easily the heat is generated, so that the braking effect is enhanced. That is, as the phase currents Iu, Iv, and Iw increase, the force applied to the deceleration imparted to the rotor 51 tends to increase.

Further, the counter electromotive force generated in each of the phase coils 54u, 54v, and 54w increases as the rotation speed R increases. Then, the phase currents Iu, Iv, and Iw tend to increase as the counter electromotive force increases. In short, the phase currents Iu, Iv, and Iw depend on the number of rotations R. [

On the other hand, in the present embodiment, in the deceleration control, the control device 60 sets the phase currents Iu, Iv, and Iw so that the phase currents Iu, Iv, and Iw do not exceed the predetermined allowable values, The switching pattern of the switching elements Qu2, Qv2 and Qw2 and the ON / OFF duty ratio D (that is, the pulse width DELTA T) are variably controlled. The allowable value is, for example, a rated current value of each switching element (Qu1 to Qw2) or a value lower by a predetermined margin than the rated current value.

Specifically, the control device 60 first determines in step S102 whether or not the number of rotations R detected in step S101 is equal to or greater than a predetermined first threshold value Rth1. When the number of rotations R is equal to or larger than the first threshold value Rth1, the control device 60 proceeds to step S103 to execute the first deceleration control.

As shown in Fig. 9, in the first deceleration control, the control device 60 sets the switching pattern to the one-phase pattern and sets the duty ratio D to the first duty ratio D1. The first duty ratio D1 is set so that the phase current Iu flowing through the switching of the one-phase pattern when the rotational speed R is the maximum value of the rotational speed R assumed under the situation that the rotational speed R is reversely rotated by the intermediate- , Iv, and Iw) is set to correspond to the counter electromotive force generated when the allowable value and the rotational speed (R) are the assumed maximum values, so as not to exceed the allowable value. That is, the first deceleration control is a deceleration control in which each of the phase currents Iu, Iv, Iw is set so as not to exceed the allowable value irrespective of the number of revolutions R of the rotor 51.

As shown in Fig. 8, after the execution of the first deceleration control, the control device 60 returns to step S101. In step S101 in this case, the control device 60 grasps the number of rotations R based on the detection results of the current sensors 61 to 63 obtained by the first deceleration control.

Further, the control device 60 makes an affirmative decision in step S102 in the situation where the first deceleration control is already being executed, and continues the first deceleration control when proceeding to step S103. That is, when the number of rotations R is equal to or larger than the first threshold value Rth1, the control device 60 continues the first deceleration control until the number of rotations R becomes less than the first threshold value Rth1 .

When the number of rotations R becomes less than the first threshold value Rth1, the control device 60 makes an affirmative decision in step S102 and proceeds to step S104. In step S104, the control device 60 determines whether the number of rotations R is equal to or greater than a second threshold value Rth2 that is lower than the first threshold value Rth1.

The control device 60 proceeds to step S105 to set the second phase current Iu, Iv, Iw higher than the first deceleration control so that the second phase current Iu, Iv, Iw is higher than the first deceleration control, when the number of rotations R is equal to or greater than the second threshold value Rth2 Deceleration control is executed. Specifically, as shown in Fig. 9, in the second deceleration control, the control device 60 sets the duty ratio D to the second duty ratio D2 and sets the switching pattern to the two-phase pattern .

Here, as shown in Figs. 10A to 10C, the two-phase pattern is a switching pattern in which the three-phase low-arm switching elements Qu2, Qv2 and Qw2 are turned ON in two predetermined orders in a predetermined order, And when the two-phase low-arm switching element is in the ON state, the other one-phase low-arm switching element is in the OFF state. For example, in the two-phase pattern, the lower arm switching element to be turned ON is the u-phase lower arm switching element Qu2 and the v-phase lower arm switching element Qv2 → the v-phase lower arm switching element Qv2 and w Upper and lower arm switching elements Qw2 → w upper and lower arm switching elements Qw2 and u upper and lower arm switching elements Qu2 → . In the two-phase pattern of the present embodiment, all of the ivory arm switching elements Qu1, Qv1, and Qw1 are maintained in the OFF state.

For example, a combination mode of Qu2, Qv2: ON and also of Qu1, Qv1, Qw1 and Qw2: OFF is referred to as a first mode and a combination mode of Qv2, Qw2: ON and Qu1, Qv1, . In this case, the control device 60 may be switched from the first mode to the second mode by periodically turning on / off each of the lower arm switching devices Qu2, Qv2, and Qw2. In other words, the switching manner in the deceleration control (two-phase pattern) includes the first aspect and the second aspect in which the ON / OFF combination of the switching elements Qu1 to Qw2 is different.

For reference, as shown in Figs. 10A to 10C, the two-phase pattern is not limited to a switching pattern in which any two-phase lower arm switching element is always in an ON state, and a two- And the one-phase ON mode in which the two-phase low-arm switching element becomes the OFF state. For example, a two-phase pattern can be expressed by the following expression: Qu2: ON and Qv2: Qw2: OFF? Qu2, Qv2: ON Qw2: OFF? Qv2: ON Qu2, Qw2: OFF? Qv2, Qw2: : ON also Qu2, Qv2: OFF → Qu2, Qw2: ON and Qv2: OFF → ... May be a switching pattern. That is, the two-phase pattern may be a switching pattern in which the lower-arm switching elements are turned on in a predetermined order by two phases via a one-phase ON period (two-phase OFF period).

The two-phase pattern may include a three-phase ON period in which all the child-element switching elements Qu2, Qv2, and Qw2 are in an ON state. For example, the 2-phase pattern can be represented as: Qu2, Qv2: ON, Qw2: OFF? Qu2, Qv2, Qw2: ON? Qv2, Qw2: ON, Qv2: OFF → Qu2, Qv2, Qw2: ON → Qu2, Qv2: ON and Qw2: OFF → ... May be a switching pattern. That is, the two-phase pattern may be a switching pattern in which the lower-arm switching elements are turned on in the predetermined order by two phases via the three-phase ON period.

Here, as described above, the timings at which the respective lower arm switching elements Qu2, Qv2 and Qw2 are brought into the ON state differ from one another by the predetermined period? A. More specifically, during the period from the time when the lower arm switching device Qu2 occurs to the time when the lower arm switching device Qv2 occurs, and when the lower arm switching device Qw2 occurs from when the lower arm switching device Qv2 occurs And the period from when the lower arm switching element Qw2 takes place to when the lower arm switching element Qu2 occurs is the same predetermined period delta a. The second duty ratio D2 is set such that the pulse width? T of each of the lower arm switching elements Qu2, Qv2 and Qw2 becomes longer than the predetermined period? A. Thereby, a two-phase pattern is realized. That is, in this embodiment, when the duty ratio D is set to the second duty ratio D2, the switching pattern is set to the two-phase pattern.

When the pulse width DELTA T of each of the lower arm switching elements Qu2, Qv2 and Qw2 is shorter than twice the predetermined period delta a, the two-phase pattern is a one- The switching pattern becomes an ON state for every two phases in a predetermined order. When the pulse width? T is longer than twice the predetermined period? A, the two-phase pattern is a switching pattern in which the lower-arm switching elements are turned ON by two phases in a predetermined order, . When the pulse width? T is equal to twice the predetermined period? A, the two-phase pattern does not include the one-phase ON period and the three-phase ON period, and the lower arm switching elements are arranged in two- The switching pattern becomes the ON state. The higher the duty ratio D, the higher the braking effect is.

For reference, the first threshold value Rth1 and the second duty ratio D2 are set such that the angular velocity generated when the second deceleration control is performed under the condition that the rotor 51 rotates at the rotation speed of the first threshold value Rth1 The phase currents Iu, Iv, and Iw are set so as not to exceed the allowable values. Therefore, the second deceleration control is referred to as deceleration control in which the phase currents Iu, Iv, Iw are set so as not to exceed the allowable values under the condition that the number of rotations R of the rotor 51 is less than the first threshold value Rth1 .

As shown in Fig. 8, after the execution of the second deceleration control, the control device 60 returns to step S101. In this case, in step S101, the control device 60 grasps the number of rotations R based on the detection results of the current sensors 61 to 63 obtained by the second deceleration control.

Further, the control device 60 makes an affirmative decision in step S104 in the situation where the second deceleration control is already being executed, and continues the second deceleration control when the process proceeds to step S105. That is, when the number of rotations R is equal to or greater than the second threshold value Rth2 and less than the first threshold value Rth1, the control device 60 determines whether the number of rotations R is less than the second threshold value Rth2 , The second deceleration control is continued.

When the number of rotations R becomes less than the second threshold value Rth2, the control device 60 makes an affirmative decision in step S104 and proceeds to step S106. In step S106, the control device 60 determines whether the number of rotations R is equal to or greater than a third threshold value Rth3 that is lower than the second threshold value Rth2.

The control device 60 proceeds to step S107 to set the third phase current Iu, Iv, Iw higher than the second deceleration control to be higher than the third deceleration control, Deceleration control is executed. More specifically, as shown in Fig. 9, the control device 60 sets the switching pattern to a two-phase pattern in the third deceleration control and sets the duty ratio D to be larger than the second duty ratio D2 And is set to a high third duty ratio D3. The third duty ratio D3 is a ratio of the phase currents I1 and I2 in the case where each of the lower arm switching elements Qu2, Qv2, and Qw2 switches in a two-phase pattern under a condition that the number of rotations R is less than the second threshold value Rth2 (Iu, Iv, Iw) do not exceed the allowable value. That is, the third deceleration control is performed so that the phase currents Iu, Iv, Iw are set so that the phase currents Iu, Iv, Iw do not exceed the allowable values under the condition that the number of rotations R of the rotor 51 is less than the second threshold value Rth2 .

As shown in Fig. 8, after the execution of the third deceleration control, the control device 60 returns to step S101. In step S101 in this case, the control device 60 grasps the number of rotations R based on the detection results of the current sensors 61 to 63 obtained by the third deceleration control.

Further, the control device 60 makes an affirmative decision in step S106 in the situation where the third deceleration control is already being executed, and continues the third deceleration control when the process proceeds to step S107. That is, when the number of rotations R is equal to or greater than the third threshold value Rth3 and less than the second threshold value Rth2, the control device 60 determines whether the number of rotations R is less than the third threshold value Rth3 , The third deceleration control is continued.

When the number of rotations R becomes less than the third threshold value Rth3, the control device 60 makes an affirmative decision in step S106 and proceeds to step S108. In step S108, the control device 60 determines whether or not the number of rotations R is equal to or greater than the fourth threshold value Rth4, which is lower than the third threshold value Rth3.

The control device 60 proceeds to step S109 to set the fourth phase current Iu, Iv, Iw higher than the third deceleration control so that the phase currents Iu, Iv, Iw are higher than the third deceleration control, when the number of rotations R is equal to or greater than the fourth threshold value Rth4 Deceleration control is executed. More specifically, as shown in Fig. 9, the control device 60 sets the switching pattern to a two-phase pattern in the fourth deceleration control and sets the duty ratio D to be larger than the third duty ratio D3 And a high fourth duty ratio D4. The fourth duty ratio D4 is a ratio of the phase currents in the case where the respective lower arm switching devices Qu2, Qv2, Qw2 switch in the two-phase pattern under the condition that the number of rotations R is less than the third threshold value Rth3 (Iu, Iv, Iw) do not exceed the allowable value. That is, the fourth deceleration control is performed so that the phase currents Iu, Iv, Iw are set so that the phase currents Iu, Iv, Iw do not exceed the allowable values under the condition that the number of rotations R of the rotor 51 is within the range smaller than the third threshold value Rth3 .

As shown in Fig. 8, after the execution of the fourth deceleration control, the control device 60 returns to step S101. In step S101 in this case, the control device 60 grasps the number of rotations R based on the detection results of the current sensors 61 to 63 obtained by the fourth deceleration control.

Further, the control device 60 makes an affirmative decision in step S108 in the situation where the fourth deceleration control is already being executed, and continues the fourth deceleration control when the process proceeds to step S109. That is, when the number of rotations R is equal to or greater than the fourth threshold value Rth4 and less than the third threshold value Rth3, the control device 60 determines whether the number of rotations R is less than the fourth threshold value Rth4 , The fourth deceleration control is continued.

When the number of rotations R becomes less than the fourth threshold value Rth4, the control device 60 makes an affirmative decision in step S108 and proceeds to step S110. In step S110, the control device 60 performs stop control to stop the rotation of the rotor 51. [ Specifically, the control device 60 holds all the lower arm switching elements Qu2, Qv2, and Qw2 in the ON state. That is, the control device 60 short-circuits all the phase coils 54u, 54v, and 54w. The stop control can also be referred to as deceleration control in which the three-phase low-arm switching elements Qu2, Qv2 and Qw2 are all set to the ON state and the duty ratio D is set to 100%.

For reference, the fourth threshold value Rth4 is set so that the number of rotations R is set so that the phase currents Iu, Iv, and Iw do not exceed the allowable values even when all the phase coils 54u, 54v, Is the fourth threshold value (Rth4).

When the control unit 60 receives the restart command from the air conditioning ECU 121 during the deceleration control or after stopping the reverse rotation of the rotor 51, the control unit 60 stops the reverse rotation of the rotor 51 And controls the inverter 55 so that the rotor 51 rotates in the forward direction.

Next, the operation of the present embodiment will be described with reference to Fig. Fig. 11 is a graph schematically showing the change of the rotation speed R after the deceleration control is started. 11, the rotational speed R obtained from the detection results of the current sensors 61 to 63 is indicated by a solid line and the actual rotational speed R is indicated by a one-dot chain line. In Fig. 11, the time change of the rotation speed R in the case of natural deceleration is indicated by a two-dot chain line.

As shown in Fig. 11, the number of rotations R and the actual number of rotations R, which are detected from the detection results of the current sensors 61 to 63, substantially coincide with each other.

When the number of rotations R is higher than the first threshold value Rth1 at the start of execution of the reverse rotation control processing, the first deceleration control is executed first. Thereafter, at the timing t1, when the number of rotations R becomes less than the first threshold value Rth1, the deceleration control shifts from the first deceleration control to the second deceleration control. At the timing t2, when the number of rotations R becomes less than the second threshold value Rth2, the deceleration control shifts from the second deceleration control to the third deceleration control. At the timing t3, when the number of rotations R becomes less than the third threshold value Rth3, the deceleration control shifts from the third deceleration control to the fourth deceleration control. At the timing t4, the rotation speed R becomes less than the fourth threshold value Rth4, whereby the low speed control is performed, and the rotation of the rotor 51 is stopped at the timing t5. As a result, as shown by the two-dot chain line in Fig. 11, the reverse rotation of the rotor 51 is stopped earlier than in the case of natural deceleration.

It is considered that the small change in the deceleration of the rotation speed R is caused by the decrease in the counter electromotive force accompanying the decrease in the rotation speed R although the deceleration control is successively changed to a higher brake effect .

Also, for the sake of convenience, each deceleration control is performed in such a manner that the phase currents Iu, Iv, Iw are increased in the order of the first deceleration control → the second deceleration control → the third deceleration control → the fourth deceleration control, Whether or not the phase currents Iu, Iv and Iw actually increase is determined in relation to the decrease of the counter electromotive force with the decrease in the number of rotations R. In this case, Therefore, the actual phase currents Iu, Iv, and Iw do not always increase in the order of the first deceleration control? Second deceleration control? Third deceleration control? Fourth deceleration control. That is to say, the variable control of the switching pattern and the duty ratio D such that the phase currents Iu, Iv and Iw become higher does not mean that the phase currents Iu, Iv and Iw actually need to be increased, So long as it is possible to suppress the decrease of the phase currents Iu, Iv and Iw. In other words, in the deceleration control, the control device 60 may employ a switching pattern and a duty ratio D that tend to increase the phase currents Iu, Iv, Iw as the rotational speed R becomes lower have.

According to the present embodiment described in detail above, the following effects are exhibited.

(1) The electric compressor 10 includes an electric motor 16 having a rotor 51, a housing 11 having a suction port 11a through which a refrigerant as a fluid is sucked, And a compression section (15) for discharging the compressed refrigerant. The compression section 15 includes a fixed scroll 31 fixed to the housing 11, a movable scroll 32 which is meshed with the fixed scroll 31 and capable of orbital motion with respect to the fixed scroll 31, And a compression chamber (33) partitioned by a scroll (31) and a movable scroll (32). The compression section 15 is configured to compress the suction refrigerant sucked into the compression chamber 33 by the idle movement of the movable scroll 32 in the forward direction when the rotor 51 rotates in the normal direction.

In this configuration, the motor-driven compressor 10 includes an injection port 43 for introducing an intermediate-pressure refrigerant, which is higher in pressure than the suction refrigerant and lower in pressure than the compressed refrigerant, into the compression chamber 33, (55), and a control device (60) for controlling the inverter (55). The inverter 55 has the ivory arm switching elements Qu1, Qv1, Qw1 and the lower arm switching elements Qu2, Qv2, Qw2 to which the same phases are connected. The controller 60 responds to the rotation of the rotor 51 in the direction opposite to the normal direction so that the lower arm switching elements Qu2, Qv2, and Qw2 are turned on so that the lower arm switching elements to be turned on are sequentially changed, The rotor 51 is decelerated to be decelerated.

According to such a configuration, the phase current corresponding to the lower arm switching element to be turned ON flows, so that the kinetic energy of the rotor 51 is converted into thermal energy. Thereby, the rotor 51 can be decelerated.

Here, it is also conceivable that the lower arm switching elements Qu2, Qv2, Qw2 are kept in the ON state without periodically turning them on and off. However, when the ON state of each of the lower arm switching elements Qu2, Qv2, and Qw2 is maintained, each of the phase currents Iu, Iv, and Iw becomes excessively high, possibly exceeding the allowable value. On the other hand, in the present embodiment, since the configuration in which the lower arm switching elements Qu2, Qv2, Qw2 are periodically turned on / off is employed, it is possible to suppress the phase currents Iu, Iv, Iw from becoming excessively high can do.

In the present embodiment, the phase currents Iu, Iv, and Iw are equal to each other because the lower arm switching elements to be turned on are sequentially changed. Thereby, the phase current per one for obtaining the desired brake effect can be reduced. Therefore, it is possible to suppress excessive increase in the phase currents Iu, Iv, and Iw for decelerating the rotor 51. [

Further, since the lower arm switching elements which are in the ON state are sequentially changed, it is possible to suppress the variation in the calorific value of the three lower arm switching elements Qu2, Qv2, Qw2. As a result, it is possible to suppress a situation in which only a specific lower arm switching element among the three subsidiary arm switching elements Qu2, Qv2 and Qw2 is overheated. Therefore, it is possible to stop the reverse rotation of the rotor 51 while suppressing the local heat generation of the specific lower arm switching element.

(2) In particular, the brake effect is generated when the lower arm switching element corresponding to the phase current becomes positive value. The phase currents that are positive values are sequentially changed in a predetermined order. For this reason, in a configuration in which only a predetermined fixed-phase lower arm switching element is periodically turned ON / OFF, deceleration is performed only during a period in which the phase current corresponding to the predetermined fixed phase becomes a positive value. In this case, intermittent deceleration is applied to the rotor 51, for example, a sufficient brake effect can not be obtained, or a problem that the reverse rotation of the rotor 51 becomes unstable may occur.

On the other hand, in the present embodiment, since the low-arm switching elements to be turned on are sequentially changed, the phase of the phase current corresponding to the phase current which is a positive value at a predetermined frequency (at least three times in this embodiment) The arm switching element can be turned ON. Thereby, the deceleration can be continuously performed, and the above problem can be suppressed.

It is also conceivable to grasp the constant current period Ta of each of the phase currents Iu, Iv and Iw in advance and control to periodically turn ON / OFF only the upper and lower arm switching elements corresponding to the constant current period Ta . However, in order to perform the control, it is necessary to grasp the rotational position of the rotor 51 and to synchronize the switching of the rotational positions with the switching of the lower arm switching elements Qu2, Qv2, Qw2. In this case, a rotation angle sensor such as a resolver is separately required or complicated control is required, which complicates the configuration.

On the contrary, in the present embodiment, since the lower arm switching elements to be in the ON state are sequentially changed as described above, the rotational position of the rotor 51 can be grasped, and the rotational position of the lower arm switching elements Qu2, Qv2 , Qw2 of the rotor 51 can be decelerated without switching. Therefore, the complexity of the configuration can be suppressed.

(3) The control device 60 grasps the rotational direction and the number of rotations (rotational speed) R of the rotor 51 and calculates the phase currents Iu, Iv, and Iv based on the detected number of rotations R, The switching pattern and the duty ratio D of each of the lower arm switching elements Qu2, Qv2, Qw2 are variably controlled so that the current Iw does not exceed a predetermined allowable value. With this configuration, even when the phase currents Iu, Iv, and Iw change in accordance with the number of rotations R, the phase currents Iu, Iv, and Iw can be prevented from exceeding the allowable values. Further, by the variable control of the switching pattern and the duty ratio D based on the number of rotations R, the brake effect can be enhanced.

(4) The control device 60 selects the switching pattern and the duty ratio D such that the phase currents Iu, Iv, and Iw become higher as the rotational speed R becomes lower. According to this configuration, since the switching pattern and the duty ratio D such that the phase currents Iu, Iv, Iw become higher as the rotation speed R is lowered, the brake effect can be enhanced. Thereby, the rotor 51 can be stopped early while suppressing excessive increase of the phase currents Iu, Iv, Iw.

As described above, each of the phase currents Iu, Iv, and Iw is likely to increase as the number of rotations R increases. If a switching pattern or a duty ratio D in which the phase currents Iu, Iv and Iw are high is used in a situation where the number of rotations R is high, the phase currents Iu, Iv and Iw are excessively large The operation of the inverter 55 may be interrupted.

On the other hand, in the present embodiment, when the number of rotations R is high, the switching pattern and the duty ratio D such that the phase currents Iu, Iv, Iw become low (for example, Duty ratio D1) is employed. As a result, the phase currents Iu, Iv, and Iw can be prevented from becoming excessively high.

On the other hand, when the rotation speed R is lowered, the counter electromotive force is lowered. Then, the phase currents Iu, Iv, and Iw are likely to be lowered. On the other hand, in the present embodiment, the switching pattern and the duty ratio D (for example, a two-phase pattern and a second duty ratio) such that the phase currents Iu, Iv and Iw become higher as the rotation speed R becomes lower, Ratio (D2), etc.) is employed. Thereby, it is possible to increase the braking effect while suppressing excessive increase of the phase currents Iu, Iv, Iw.

(5) In the switching pattern, the three-phase low-arm switching elements Qu2, Qv2 and Qw2 are turned ON in a predetermined order in a predetermined order. When the one-phase low-arm switching element is ON, And a one-phase pattern including an aspect in which the switching element is turned off. The one-phase pattern is a switching pattern in which a plurality of lower-arm switching elements are not turned ON at the same time.

In the switching pattern, the three-phase low-arm switching elements Qu2, Qv2 and Qw2 are turned ON in the predetermined order by two phases, and when the two-phase low-arm switching element is in the ON state, the other one- OFF state of the two-phase pattern.

When the number of rotations R is equal to or greater than the first threshold value Rth1, the control device 60 executes the first deceleration control in which the switching pattern is a one-phase pattern, and when the number of rotations R reaches the first threshold value Rth1), the deceleration control in which the switching pattern is a two-phase pattern, specifically, the second deceleration control, the third deceleration control, or the fourth deceleration control is executed.

With this configuration, when the number of rotations R is equal to or larger than the first threshold value Rth1, the switching pattern is set to the one-phase pattern. This one-phase pattern is a switching pattern in which each of the phase currents Iu, Iv, Iw tends to be lower than the two-phase pattern. Thereby, it is possible to decelerate the rotor 51 while suppressing excessive increase in the phase currents Iu, Iv, Iw in a situation where the rotation speed R is relatively high.

On the other hand, when the number of rotations R is less than the first threshold value Rth1, the phase currents Iu, Iv, and Iw do not become high. In this case, the switching pattern is set as a two-phase pattern. This two-phase pattern is a switching pattern in which each of the phase currents Iu, Iv, and Iw tends to be higher than the one-phase pattern. Specifically, since there is an aspect in which the two-phase low-arm switching element of the two phases is turned ON at the same time, the lower arm switching element corresponding to the phase current which becomes the positive value at two times of the three switching operations related to the present embodiment It can be turned ON. Therefore, since the brake effect can be enhanced, the rotor 51 can be stopped earlier.

(6) The control device 60 increases the duty ratio D as the rotational speed R is lowered. With this configuration, as the rotation speed R is lowered, the brake effect can be enhanced. As a result, the rotor 51 can be stopped earlier while suppressing excessive increase in the phase currents Iu, Iv, and Iw.

(7) The control device 60 grasps the rotational direction and the rotational speed R of the rotor 51 based on the phase currents Iu, Iv, and Iw flowing through the deceleration control. According to this configuration, since the rotation direction and the rotation number R of the rotor 51 can be grasped without forming a dedicated sensor or the like, sensorlessization can be achieved. It is also possible to effectively utilize the deceleration control by grasping the rotational direction and the number of rotations R of the rotor 51 based on the phase currents Iu, Iv, and Iw flowing through the deceleration control. In other words, it is possible to simplify the control by the amount of current control that is not required to be carried out in order to grasp the rotational direction and the number of rotations R of the rotor 51.

(8) The electric compressor 10 is mounted on a vehicle, and is used in the vehicle air conditioning system 100. Here, the vehicle air conditioning system 100 including the electric compressor 10 may be exposed under a low-temperature environment, for example, in relation to being mounted on a vehicle. Under such a low-temperature environment, since the density of the refrigerant is lowered, the ability of the motor-driven compressor 10 is likely to deteriorate. On the other hand, in the present embodiment, the ability of the motor-driven compressor 10 can be improved by sucking the intermediate-pressure refrigerant into the compression chamber 33 through the injection port 43 as described above. However, in this case, a reverse rotation phenomenon may occur when the operation of the electric compressor 10 is stopped. Then, since the motor-compressor 10 can not be restarted until the rotor 51 stops, the period required from the operation stop to the restart operation tends to become long.

Further, when the motor-driven compressor 10 is used in the vehicle air conditioning system 100, there are a plurality of factors for stopping and restarting the motor-driven compressor 10, such as an operation from the user and a running state of the vehicle. And, if the time is longer, the comfort of the room is deteriorated.

On the other hand, in the present embodiment, since the rotation of the rotor 51 can be stopped relatively early by performing the deceleration control as described above, the restart of the motor-driven compressor 10 can be realized early. This makes it possible to both suppress the deterioration of the performance of the vehicle air conditioning apparatus 100 at a low temperature and improve the comfort.

The above embodiment may be modified as follows.

In the embodiment, the three-phase target arm switching elements to be subjected to the switching operation are the respective lower arm switching elements Qu2, Qv2 and Qw2, but the present invention is not limited to this. For example, each of the ivory arm switching elements Qu1, Qv1, It may be. Specifically, the control device 60 periodically turns on / off each of the ivory arm switching elements Qu1, Qv1, and Qw1 so that the ivory arm switching elements to be turned on are sequentially switched, thereby rotating the rotor 51 It may be decelerated. In this case, the lower arm switching elements Qu2, Qv2, and Qw2 may be kept in the OFF state, for example. The current sensors 61 to 63 may be formed between the ivory arm switching elements Qu1 to Qw1 and the first power line EL1 in the upper wirings ELu to ELw.

That is, the switching control mode of the control device 60 in the deceleration control may be such that each of the ivory arm switching elements Qu1, Qv1, Qw1 is switched to operate so that the ivory arm switching elements to be turned on are sequentially switched .

The controller 60 also performs switching operation (that is, periodically ON / OFF) of each of the ivory arm switching elements Qu1, Qv1, Qw1 and each of the lower arm switching elements Qu2, Qv2, Qw2 do. That is, the three-phase target arm switching device to be a switching operation may be both of the three-phase ivory arm switching devices Qu1, Qv1, Qw1 and the three-phase lower arm switching devices Qu2, Qv2, Qw2. In this case, the control device 60 may be controlled such that the ivory arm switching element and the lower arm switching element of the same phase are not turned on at the same time. More specifically, the switching control mode of the control device 60 is such that the ivory arm switching elements that are turned on are sequentially switched so that the ivory arm switching element and the lower arm switching element of the same phase are not simultaneously turned on, It may be an aspect of sequentially switching the lower arm switching elements to be in the ON state.

That is, in the deceleration control, the control device 60 turns on at least one of the three-phase armature switching elements Qu1, Qv1, Qw1 and the three armature switching elements Qu2, Qv2, Qw2 of three phases So that the rotor 51 is decelerated. In this case, the switching control mode of the control device 60 in the deceleration control is such that one or a plurality of switching elements of all the switching elements Qu1 to Qw2 are turned on and the other switching elements are turned off And the combination of the switching element to be in the ON state and the switching element to be in the OFF state includes the second aspect which is different from the first aspect. Thereby, it is possible to suppress a situation in which only a specific switching element locally generates heat, and it is possible to stop the rotor 51 preferably through this.

In the second aspect, a combination of the ON / OFF states of the switching elements Qu1 to Qw2 may be different from the first aspect, and a part of the switching elements in the ON state may overlap with the first aspect. For example, in the two-phase pattern, an aspect of Qu2, Qv2: ON, and Qu1, Qv1, Qw1 and Qw2: OFF is referred to as a first mode, and Qv2, Qw2: ON and Qu1, Qv1, Qw1, It is called the second aspect. In this case, the v-phase and lower-arm switching device Qv2 is in the ON state in both the first and second aspects. On the other hand, in the first embodiment, the u-phase lower arm switching device Qu2 is turned ON and the w-phase lower arm switching device Qw2 is turned ON in the second mode. Therefore, in the first and second aspects, , The switching elements in the ON state are different.

The control device 60 may be configured to variably control either the switching pattern or the duty ratio D. [ For example, the control device 60 may fix the switching pattern to either the one-phase pattern or the two-phase pattern, and may variably control only the duty ratio D. Alternatively, the duty ratio D may be fixed, , A one-phase pattern or a two-phase pattern. In essence, the control device 60 may variably control at least one of the switching pattern and the duty ratio D in accordance with the number of rotations R.

Control device 60 may continuously and variably control the duty ratio D such that the duty ratio D gradually increases as the rotational speed R becomes lower.

The order of the lower arm switching elements to be turned ON in the one-phase pattern is arbitrary. For example, in the one-phase pattern, the lower arm switching element to be in the ON state is composed of the w-phase lower arm switching element Qw2 → v-phase lower arm switching element Qv2 → u-phase lower arm switching element Qu2 . The same applies to the two-phase pattern.

In the two-phase pattern, combinations of phases that are in the ON state at any time are arbitrary.

The switching pattern is arbitrary as long as the target arm switching element to be turned ON is sequentially changed. For example, the switching pattern may be an aspect in which the target arm switching elements are turned ON by one by one in a predetermined order through a three-phase ON period in which all the three-phase target arm switching elements are in the ON state.

In the two-phase pattern described in the embodiment, the timing at which each of the lower arm switching elements Qu2, Qv2, and Qw2 occurs in the ON state is shifted, but the present invention is not limited to this. For example, the two-phase pattern may be a switching pattern in which the timing of the two-phase low-arm switching element to occur in the ON state coincides with each other. For example, the two-phase pattern can be expressed as follows: Qu2, Qv2: ON, Qw2: OFF? Qu2, Qv2, Qw2: OFF? Qv2, Qw2: Qv2: OFF? Qu2, Qv2, Qw2: OFF? Qu2, Qv2: ON and Qw2: OFF? May be a switching pattern. That is, the two-phase pattern may be a switching pattern in which the target arm switching elements are turned on for every two phases in a predetermined order via an interval period in which all of the three-phase target arm switching elements are in the OFF state. In other words, the two-phase pattern includes a switching pattern including an interval period, a switching pattern including a one-phase ON period, a switching pattern including a three-phase ON period, and a switching period including an interval period, At least one of the switching patterns not including any period of the period is included.

In the embodiment, since the timing at which each of the lower arm switching elements Qu2, Qv2, Qw2 is turned ON is shifted, the duty ratio D is adjusted so that the switching pattern is a one-phase pattern or a two- It changed. However, as described above, even when the duty ratio D is adjusted, when two of the lower arm switching elements Qu2, Qv2 and Qw2 are ON at the same timing (that is, when there is no phase shift) Do not change. That is, the duty ratio D and the switching pattern may or may not be related to each other.

The specific configuration of the control device 60 for grasping the rotational direction and the rotational speed R of the rotor 51 is arbitrary, and for example, a rotational angle sensor such as a resolver is formed, and the detection result of the rotational angle sensor Or the like.

The position and the number of the injection port 43 are arbitrary.

The object to which the electric compressor 10 is to be mounted is not limited to the vehicle, but may be arbitrary.

Although the electric compressor 10 is used in the vehicle air conditioning system 100, the electric compressor 10 is not limited to this, and may be used in other devices. For example, when the vehicle is a fuel cell vehicle (FCV) equipped with a fuel cell, the electric compressor 10 may be used for a supply device for supplying air to the fuel cell. In essence, the fluid to be compressed is arbitrary, and may be a refrigerant or air.

The embodiments and the separate examples may be appropriately combined. For example, the control device 60 performs the switching operation of the three-phase armature switching elements Qu1, Qv1, and Qw1 so that the ivory arm switching elements to be turned on are sequentially changed, The switching operation of the three-phase lower arm switching devices Qu2, Qv2, and Qw2 may be performed so that the lower-arm switching devices sequentially change. For example, the control device 60 performs a switching operation on the three-phase upper arm switching elements Qu1, Qv1, Qw1 or the three-phase lower arm switching elements Qu2, Qv2, Qw2, The switching operation may be performed on the elements Qu1 to Qw2.

Claims (8)

A three-phase motor having a rotor,
A housing having a suction port through which fluid is sucked,
A compression unit that is driven by the three-phase motor and compresses the suction fluid that is the fluid sucked from the suction port and discharges the compressed fluid that is the compressed suction fluid;
A drive circuit for driving the three-phase motor,
And a control section for controlling the drive circuit,
Wherein the compression unit comprises:
A fixed scroll fixed to the housing,
A movable scroll engaging with the fixed scroll and configured to revolve against the fixed scroll;
Wherein the compression chamber is divided by the fixed scroll and the movable scroll, and when the rotor rotates in a predetermined normal direction, the movable scroll is revolved in the forward direction, Compressing the fluid,
Wherein the motor-driven compressor has an injection port for introducing an intermediate-pressure fluid having a higher pressure than the suction fluid and lower than the compressed fluid into the compression chamber,
Wherein the driving circuit comprises:
Phase u-phase arm switching element and u-phase lower arm switching element connected to each other,
A v-phase ivory arm switching element and a v-phase lower arm switching element connected to each other,
Phase woof-arm switching element and a wo-phase lower arm switching element connected to each other,
Wherein the control unit is configured to perform deceleration control for decelerating the rotor in response to the rotor being rotated in a direction opposite to the forward direction and wherein the control unit controls the three- A first aspect in which one or a plurality of switching elements among the three-phase lower arm switching elements are turned ON and the other switching elements are turned OFF, and a combination of a switching element which is turned ON and a switching element which is turned OFF, Wherein the drive circuit is configured to control the drive circuit in a switching control mode that includes a second aspect that is different from the first aspect. The method according to claim 1,
Wherein the switching control mode in the deceleration control includes:
An embodiment in which the three-phase arm switching element is switched so as to sequentially change the ivory arm switching elements to be turned ON,
An embodiment in which the three-phase lower arm switching element is switched so that the lower arm switching elements to be turned ON sequentially change,
or,
Both of the three-phase arm switching element and the three-phase subsidiary arm switching element are switched so that the switching elements which are also in the ON state are sequentially switched so that the ivory arm switching element and the lower arm switching element of the same phase are not simultaneously turned ON The motor-driven compressor comprising: 3. The method of claim 2,
And a grasping portion for grasping the rotational direction and the number of rotations of the rotor,
Wherein the control unit controls the three-phase target to be switched in the deceleration control so that the current flowing to the three-phase motor does not exceed a predetermined allowable value, based on the number of rotations detected by the holding unit, And to control at least one of a switching pattern and a duty ratio of the arm switching element to be variable. The method of claim 3,
The switching pattern includes:
When the target arm switching element of one phase of the three-phase arm switching elements is in the ON state, and the other two-phase target arm switching elements are in the OFF state, and when the target arm switching elements of the three phases are not in the ON state at the same time Phase pattern,
And a two-phase pattern including an aspect in which the target arm switching element of the other phase of the two-phase target arm switching element becomes the OFF state when the target arm switching element of the three-phase target arm switching element is in the ON state,
Wherein the control unit sets the switching pattern to the one-phase pattern when the number of rotations is equal to or greater than a predetermined threshold, and sets the switching pattern to the two-phase pattern when the number of rotations is less than the threshold. The method of claim 3,
Wherein the control unit is configured to increase the duty ratio as the rotation speed decreases. The method of claim 3,
Wherein the grasping portion grasps the rotational direction and the rotational speed of the rotor based on the current flowing through the three-phase motor by the deceleration control. The method of claim 3,
Wherein the controller is configured to select the switching pattern and the duty ratio which tend to increase the current flowing to the three-phase motor as the rotational speed decreases. 8. The method according to any one of claims 1 to 7,
Wherein the electric compressor is mounted on a vehicle and is used in a vehicle air conditioner.

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