JP2018003787A - Compressor motor control device and electric compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of logics executed every time an electric compressor is stopped in its operation and further to restrict burden for processing and consumption power.SOLUTION: When a compressor 1 being operated is stopped, an electric current is flowed at a coil 5d of each of the phases of a stator 5c for a quite short time in which a rotor 5b is not rotated to attain α-axis current iα and β-axis current iβ from electric currents flowed at the coil 5d of each of the phases and an electric angle of an electric motor 5 is calculated in reference to a table from the combination of the attained values. Then, if the calculated electric angle is an electric angle corresponding to a rotating angle other than a rotating angle where it is stopped only when the compressor 1 is stopped due to loss of synchronism of the electric motor 5 or stoppage of electrical energization, it is judged that a mechanical lock is produced at the compressor 1.SELECTED DRAWING: Figure 16

Description

  The present invention relates to an electric compressor and a control device for a motor that rotates the electric compressor.

  If the electric compressor that drives the compression mechanism to rotate with the electric motor stops during operation, the reason for this is mechanical locking due to poor lubrication of the rotating part or biting of foreign matter, or the rotational speed command value for the electric motor. A step-out of the electric motor due to an overload caused by a sudden change can be considered.

  If the cause of the stop of the electric compressor is an overload of the electric motor, the electric compressor may be restarted. However, if the cause is a mechanical lock, the electric compressor will not operate even if it is restarted unless the cause is resolved. Rather, it will cause the electric motor to fall into an overcurrent state by restarting the electric compressor. The situation may be further exacerbated.

  Therefore, it is very useful to confirm whether the stop is caused by a mechanical lock when the electric compressor is stopped, and a method for that purpose has been proposed. In the proposed method, when the electric compressor is stopped, a high-frequency current corresponding to 360 ° of the electrical angle is caused to flow through the rotor of an interior permanent magnet (IPM) rotor of the electric motor to detect the rotor stop angle. , Make a DC forced current flow.

  If there is no mechanical lock, the electric motor should rotate and the stop angle should change by allowing a DC forcing current to flow. A stop angle is detected, and it is determined whether or not it matches the previously detected stop angle. Thereby, when a mechanical lock | rock occurs, it can detect that (for example, patent document 1).

Japanese Patent No. 4449290

  However, the proposed method described above must be performed by executing a complicated logic by a combination of AC driving and DC driving every time the electric compressor is stopped, and the processing load is large and the power consumption is large. There are disadvantages.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce the logic executed each time the electric compressor is stopped, and to reduce the processing load and power consumption. And it is providing the suitable electric compressor using this.

In order to achieve the above object, a compressor motor control device according to a first aspect of the present invention comprises:
In a motor control device that rotates a rotating shaft connected to a rotating body of a compression mechanism of a compressor in which inhaled gas is compressed,
An orthogonal coordinate system according to the electrical angle of the rotor of the motor based on the position of the stator of the motor from the current flowing through the coil by passing a current for position detection to the coil of the motor while the motor is stopped Shaft current detecting means for detecting the shaft current of
Electrical angle detection means for detecting the electrical angle corresponding to the shaft current detected by the shaft current detection means;
Lock detection means for evaluating the electrical angle detected by the electrical angle detection means, and detecting from the result of the evaluation that the mechanical lock of the compressor has occurred;
Is provided.

In order to achieve the above object, an electric compressor according to the second aspect of the present invention includes:
A compression mechanism in which the sucked gas is compressed by rotation of the rotating body;
A motor for rotating a rotating shaft connected to the rotating body;
A control device for controlling the motor,
The compressor motor control device according to claim 1, 2, 3, 4 or 5 is used as the control device.

  According to the present invention, it is possible to reduce the logic executed each time the electric compressor is stopped, and to reduce the processing load and power consumption.

It is sectional drawing which shows the electric compressor which concerns on one Embodiment of this invention. It is an expanded sectional view of the compression mechanism of FIG. It is explanatory drawing which shows the electrical structure of the electric compressor of FIG. It is a graph which shows the relationship between the rotor rotation angle of the compression mechanism of FIG. 1, and load torque. It is a graph which shows the relationship between the mechanical angle of the rotor of the compression mechanism of FIG. 1, and the rotation angle which a rotor stops by rotational frictional force. It is explanatory drawing which shows the logarithm of the magnetic pole which the rotor of the electric motor of FIG. 1 has. It is a graph which shows the relationship between the mechanical angle of the rotor of the compression mechanism of FIG. 1, the electrical angle of an electric motor, and the rotation angle which a rotor stops by rotational frictional force. The relationship between the current of each axis and the mechanical angle of the rotor when the vector of the current flowing through the coils of each phase of the UVW of the electric motor in FIG. 1 is converted into the α-axis and β-axis orthogonal coordinate systems based on the position of the stator. It is a graph which shows. It is a graph which shows the relationship between each axis | shaft current of (alpha) axis | shaft of FIG. 8, and the electrical angle of an electric motor. It is a graph which shows the relationship between each axial electric current of (alpha) axis | shaft of FIG. It is explanatory drawing which shows the state of the inverter circuit at the time of energizing the coil of a stator in order for the motor control part of FIG. 3 to detect the electrical angle of an electric motor. It is a graph which shows the relationship between the switching waveform of the motor control part with respect to the inverter circuit of FIG. 11, and the waveform of the electric current which passed through the coil of the electric motor. It is a graph which shows the alpha-axis current and beta-axis current of the coil of the electric motor calculated | required by the electricity supply which the motor control part of FIG. 3 performed. It is a flowchart which shows the procedure of the control which the motor control part of FIG. 3 performs when a compressor stops. It is a flowchart which shows the procedure of the electrical angle detection process of FIG. It is explanatory drawing which shows the relationship between the mechanical angle of the rotor of the compression mechanism of FIG. 1, the rotation angle which a rotor stops by rotational friction force, and the rotation angle which a rotor stops at the time of a mechanical lock of a compressor. It is a flowchart which shows the procedure of the control which the motor control part of FIG. 3 in the electric compressor which concerns on other embodiment of this invention performs when a compressor stops.

  Hereinafter, an embodiment in which the present invention is applied to an electric compressor having a vane rotary type compression mechanism will be described with reference to the drawings.

  FIG. 1 is a front sectional view showing a schematic configuration of an electric compressor according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of the compression mechanism of FIG. In the present embodiment, an electric compressor having a vane rotary type compression mechanism having three vanes will be described as an example. An electric compressor 1 according to the present embodiment shown in FIG. 1 compresses a refrigerant by driving a rotary compression mechanism 3 with an electric motor 5.

  The electric compressor 1 (corresponding to the compressor in the claims) includes a compression mechanism 3 and an electric motor 5, a housing 7 in which these are accommodated, and a controller 15.

  The compression mechanism 3 includes a pair of side blocks 3a and 3b, a cylinder block 3c sandwiched between them, and a columnar rotor 3e accommodated in an elliptical cylinder chamber 3d formed inside the cylinder block 3c. doing.

  The rotor 3e (corresponding to the rotating body in the claims) is attached to the rotating shaft 5a of the electric motor 5 supported by the bearing portions 3f, 3g of the side blocks 3a, 3b. As shown in FIG. A vane 33 is supported in each of the three vane grooves 31 opened on the peripheral surface of 3e so as to be able to protrude and retract from the peripheral surface of the rotor 3e. The vane groove 31 and the vane 33 are arranged at intervals of 120 ° in the rotation direction X (forward direction) of the rotor 3e.

  When the rotor 3e is rotated in the rotation direction X (positive direction) in the cylinder chamber 3d by the electric motor 5, each vane 33 of the rotor 3e protrudes and retracts from the vane groove 31 along the inner peripheral surface of the cylinder chamber 3d. The volume of the compression chamber 35 composed of the two vanes 33 adjacent to 3e and the cylinder chamber 3d changes.

  Then, while the volume of the compression chamber 35 increases, a low-pressure refrigerant is sucked through a suction port (not shown) formed in the side block 3 a, and the sucked refrigerant is compressed as the volume of the compression chamber 35 decreases. Is done. The compressed high-pressure refrigerant opens the discharge valve 3m of the discharge port 3l of the cylinder block 3c, and is further discharged from a discharge port (not shown) formed in the side block 3b.

  As shown in FIG. 1, an electric motor 5 (corresponding to a motor in claims) includes a rotor 5b (corresponding to a rotor in claims) attached to a rotating shaft 5a, and a stator disposed outside the rotor 5b. 5c. The stator 5c has teeth (not shown) corresponding to a plurality of poles, and a coil 5d is wound around each tooth. The electric motor 5 rotates the rotor 5b by generating a rotating magnetic field in the stator 5c by applying a voltage in a predetermined pattern to each coil 5d.

  The housing 7 has a cylindrical shape with one end closed. The housing 7 accommodates the compression mechanism 3, and the accommodated compression mechanism 3 exposes the inside of the housing 7 to the closed discharge chamber 7 a on the closed side where the side block 3 b is exposed and the side block 3 a. It is partitioned off from the suction chamber 7b on the opening side. An electric motor 5 is accommodated in the suction chamber 7 b, and the suction chamber 7 b is sealed by a lid portion 9 attached to the opening 7 c of the housing 7.

  The suction chamber 7b described above is a space where the low-temperature and low-pressure refrigerant compressed by the compression mechanism 3 is sucked from the outside of the electric compressor 1 (for example, an evaporator of the refrigeration cycle) through a suction port (not shown).

  Further, the discharge chamber 7a, which is hermetically partitioned from the suction chamber 7b by the compression mechanism 3, allows the high-temperature and high-pressure refrigerant compressed by the compression mechanism 3 to be discharged to the outside of the electric compressor 1 (for example, refrigeration This is the space discharged to the condenser of the cycle. A liquid reservoir 7d for storing the lubricating oil 11 is formed in the lower portion of the discharge chamber 7a. A liquid phase refrigerant (not shown) in the discharge chamber 7a is also retained in the liquid reservoir 7d.

  The lubricating oil 11 in the liquid pool portion 7d is supplied to the bearing portions 3f and 3g of the side blocks 3a and 3b by the pressure of the refrigerant in the discharge chamber 7a, and is used for lubricating the rotating shaft 5a that the bearing portions 3f and 3g support. . The bearing portions 3f and 3g are formed by annular grooves formed on the inner peripheral surface of the through hole through which the rotation shaft 5a of the side blocks 3a and 3b passes.

  The lubricating oil 11 in the liquid reservoir 7d is supplied to the bearing portion 3f of the side block 3a through the passage 3h of the side block 3b, the passage 3i of the cylinder block 3c, and the passage 3j of the side block 3a. The lubricating oil 11 in the liquid reservoir 7d is supplied to the bearing portion 3g of the side block 3b through the passage 3k of the side block 3b.

  The lubricating oil 11 supplied to the bearing portions 3f and 3g of the side blocks 3a and 3b flows into the suction chamber 7b through a gap with the rotating shaft 5a and accumulates at the bottom of the suction chamber 7b. The liquid-phase refrigerant sucked into the suction chamber 7b also collects at the bottom of the suction chamber 7b. Lubricating oil 11 and liquid-phase refrigerant accumulated at the bottom of the suction chamber 7b ride on the refrigerant flow in the suction chamber 7b and are sucked into the cylinder chamber 3d of the compression mechanism 3, where they are mixed with the compressed high-pressure refrigerant. It is discharged into the discharge chamber 7a.

  Therefore, the discharge chamber 7a is provided with an oil separator 7e that separates the lubricating oil 11 from the high-pressure refrigerant. The lubricating oil 11 separated from the refrigerant by the oil separator 7e is retained in the liquid reservoir 7d at the lower part of the discharge chamber 7a together with the liquid-phase refrigerant (not shown) in the discharge chamber 7a.

  The controller 15 (corresponding to the control device and the compressor motor control device in the claims) has an inverter circuit 15a and a motor control unit 15b as shown in the explanatory diagram of FIG.

  The inverter circuit 15 a converts the electric power of the DC power supply 13 into AC and supplies it to the U, V, W phase coils 5 d of the stator 5 c of the electric motor 5. The inverter circuit 15a includes IGBTs (Insulated Gate Bipolar Transistors) Q1 to Q6 as power switching elements for the upper arm and the lower arm corresponding to the coils 5d of each phase.

  The IGBTs Q1 to Q6 may be replaced with power transistors such as MOSFETs (Metal Oxide Semiconductor Field Effect Transistors).

  The motor control unit 15b (corresponding to the shaft current detection means, the electrical angle detection means, and the activation control means in the claims) applies to each coil 5d according to a predetermined pattern for generating a rotating magnetic field in the stator 5c of the electric motor 5. For controlling voltage application, for example, a microcomputer is used.

  The motor control unit 15b performs voltage application to each coil 5d by sensorless vector control in a steady period after the rotor 5b reaches a constant rotational speed. In sensorless vector control, the rotation angle of the rotor 5b is specified sensorlessly using the induced current or voltage flowing through the non-excited phase coil 5d of the stator 5c, and the rotating magnetic field rotates in accordance with the rotation angle of the rotor 5b. Thus, a voltage is applied to each coil 5d.

  On the other hand, since the induced current or voltage flowing through the coil 5d of the stator 5c is small during the start-up period from when the rotor 5b starts to reach a certain rotational speed, the rotation angle of the rotor 5b is specified using this. I can't. Accordingly, the motor control unit 15b performs voltage application to each coil 5d by synchronous control (synchronous operation) during the start-up period. In the synchronous control, a voltage is applied to each coil 5d so that the rotor 5b whose rotation angle is unknown rotates in synchronization with the rotation of the rotating magnetic field generated in the stator 5c.

  During synchronous control, the motor control unit 15b applies a voltage to the coils 5d of the U, V, and W phases of the stator 5c so that a torque exceeding the starting torque of the rotor 3e of the compression mechanism 3 is generated. It is necessary to prevent the electric compressor 1 from starting up.

  Incidentally, as shown in the graph of FIG. 4, the load torque of the rotor 3e varies depending on the rotation angle of the rotor 3e. The load torque varies depending on the rotation angle of the rotor 3e because the volume of the compression chamber 35 between the two adjacent vanes 33 and 33 in the cylinder chamber 3d changes as the rotor 3e rotates, and the refrigerant in the compression chamber 35 changes. This is because the pressure increases due to compression.

  That is, at the rotation angle of the rotor 3e when the refrigerant is sucked into the compression chamber 35, the load torque of the rotor 3e is low because the refrigerant pressure in the compression chamber 35 is low. On the other hand, at the rotation angle of the rotor 3e when the sucked refrigerant is compressed to the point of discharge in the compression chamber 35, the load torque of the rotor 3e is high because the refrigerant pressure in the compression chamber 35 is high. For this reason, the fluctuation of the load torque of the rotor 3e fluctuates at a period interlocked with the rotation of the rotor 3e.

  Further, when the electric motor 5 is stopped, the rotor 3e rotates in the reverse direction (reverse rotation) by the differential pressure between the refrigerant pressure in the discharge chamber 7a and the refrigerant pressure in the suction chamber 7b. When the rotational friction force applied to the rotor 3e due to the sliding of the vane 33 with respect to the inner peripheral surface of the cylinder chamber 3d exceeds the differential pressure between the refrigerant pressure in the discharge chamber 7a and the refrigerant pressure in the suction chamber 7b, the reverse of the rotor 3e. The rotation stops.

  In the electric compressor 1 of the present embodiment, the three vanes 33 protruding from the three vane grooves 35 formed on the peripheral surface of the rotor 3e at intervals of 120 ° slide on the inner peripheral surface of the cylinder chamber 3d. For this reason, the position where the rotor 3e, which rotates in reverse after the electric motor 5 stops, is stopped by the rotational frictional force (vane friction) between the vane 33 and the inner peripheral surface of the cylinder chamber 3d, as shown in the graph of FIG. There are three locations at intervals of 120 ° during one rotation of 3e.

  As a method for detecting the rotation angle of the rotor 5b, it is detected from the current that actually flows through the coil 5d when the rotor 5b of the electric motor 5 energizes the coils 5d of the U, V, and W phases of the stator 5c. It is conceivable to use the electrical angle of the electric motor 5.

  Here, the electrical angle of the electric motor 5 is an angle obtained by multiplying the rotation angle of the rotor 5b by the number of magnetic pole pairs (number of pole pairs) formed by the permanent magnets of the rotor 5b. In the present embodiment, as shown in the explanatory diagram of FIG. 6, the rotor 5 b has two pairs of the S pole and the N pole, and therefore, with respect to the rotation angle of the rotor 5 b having two pole pairs. The electrical angle of the electric motor 5 is twice as shown in the graph of FIG.

  By the way, when the electric angle of the electric motor 5 is obtained from the current flowing through the coil 5d of the stator 5c, the orthogonal coordinate system (α (Axis, β axis) vector.

  The currents (α-axis current iα, β-axis current iβ) in the orthogonal coordinate system after the coordinate conversion change at a cycle twice the electrical angle of the electric motor 5 as shown in the graph of FIG. Such a change is significant when the electric motor 5 is an IPM motor using an interior permanent magnet (IPM) rotor 5b in which a permanent magnet is embedded as shown in FIG. Become. This is because the motor torque of the electric motor 5 is a combination of the magnet torque and the reluctance torque.

  Even in an SPM motor using a surface permanent magnet (SPM) rotor 5b with a permanent magnet exposed on the surface, the motor torque includes a slight reluctance torque. For this reason, even when the electric motor 5 is an SPM motor, although the amplitude is smaller than the change shown in the graph of FIG. 8, the α-axis current iα and the β-axis current iβ periodically change.

  Then, at the electrical angles corresponding to the three rotational angles at which the rotor 3e of the compression mechanism 3 is stopped by the rotational frictional force between the vane 33 and the inner peripheral surface of the cylinder chamber 3d due to the step-out of the electric motor 5 or the stop of energization, The values of the α-axis current iα and the β-axis current iβ corresponding to the angle are combinations of different values as indicated by points C, D, and E in FIG.

  Therefore, in the electric compressor 1 of the present embodiment, before starting the electric motor 5, the motor control unit 15b detects the electric angle of the electric motor 5 for such a short time that the rotor 5b does not rotate. Energization is performed on the coils 5d of each phase of the stator 5c.

  In this energization, for example, a single shunt method is used, and a pulse signal shown at the top of the graph of FIG. 12 for turning on the IGBTs Q1, Q5, and Q6 of the inverter circuit 15a with a pattern shown in the explanatory diagram of FIG. The unit 15b outputs. Accordingly, when the current (iu, iv, iw) having the waveform shown in the lower part of the graph of FIG. 12 flows through the coils 5d of the U, V, W phases of the stator 5c, the current (iu, iv, iw) The motor control unit 15b obtains the values of the α-axis current iα and the β-axis current iβ using the conversion formula shown in FIG.

  Then, the motor control unit 15b refers to a table 15d stored in advance in a memory 15c (not shown) inside, and the motor control unit 15b corresponds to the combination of the α-axis current iα and the β-axis current iβ obtained by the motor control unit 15b. The electrical angle of the motor 5 is specified. In this table 15d, the combination of the α-axis current iα and the β-axis current iβ, the electrical angle of the electric motor 5 at which the rotor 3e of the compression mechanism 3 stops due to the rotational frictional force between the vane 33 and the inner peripheral surface of the cylinder chamber 3d, Are associated.

  Here, if the combination of the values of the α-axis current iα and the β-axis current iβ is the value of the α-axis current iα and the β-axis current iβ at the point a in the graph of FIG. 13, the motor control unit 15b It is confirmed whether or not the electrical angle of the electric motor 5 corresponding to the combination of values is defined in the table 15d of FIG.

  Then, when the electrical angle of the electric motor 5 corresponding to the combination of the values of the α-axis current iα and the β-axis current iβ is defined in the table 15d of FIG. This is used to determine the cause of the electric compressor 1 being stopped by the procedure.

  Note that the rotation angle at which the rotor 3e of the compression mechanism 3 stops due to the rotational frictional force between the vane 33 and the inner peripheral surface of the cylinder chamber 3d, and the electrical angles of the electric motor 5 when the rotor 3e is at that rotation angle. The corresponding α-axis current iα and β-axis current iβ are determined by the number of counter electrodes of the rotor 5 b of the electric motor 5 and the number of vanes 33.

  The motor control unit 15b performs a process of determining the cause when the electric compressor 1 in operation is stopped. The reason why the motor control unit 15b determines is that the mechanical lock generated in the rotating portion of the electric compressor 1, particularly the compression mechanism 3 or the electric motor 5, or the normal stop due to the electric motor 5 being stepped out or being de-energized. This is a rotational friction force (vane friction) that sometimes occurs between the inner peripheral surface of the cylinder chamber 3d and the vane 33 and exceeds the differential pressure between the refrigerant pressure in the discharge chamber 7a and the refrigerant pressure in the suction chamber 7b.

  Hereinafter, a procedure of processing when the motor control unit 15b determines the cause when the electric compressor 1 in operation is stopped will be described with reference to the flowcharts of FIGS.

  First, the motor control unit 15b periodically and repeatedly executes the process of the flowchart shown in FIG. Then, the motor control unit 15b first checks whether or not the operating electric compressor 1 has stopped (step S1).

  The fact that the electric compressor 1 in operation has stopped is, for example, the state in which the motor control unit 15b receives a command value (however, other than zero) for the torque or the number of rotations of the electric motor 5 from the controller 15. It can be recognized by the fact that the input of the rotation pulse from has stopped.

  If the operating electric compressor 1 is not stopped (NO in step S1), the series of processing ends, and if it is stopped (YES in step S1), the motor control unit 15b The electrical angle of the rotor 5b of No. 5 is detected (step S3).

  In this electrical angle detection process, as shown in FIG. 15, the motor control unit 15 b applies energization for detecting the electrical angle of the electric motor 5 to the coils 5 d of the U, V, and W phases of the stator 5 c. For a short time (step S21).

  Next, the motor control unit 15b obtains the α-axis current iα and the β-axis current iβ from the currents (iu, iv, iw) flowing through the coils 5d of each phase using the conversion formula shown in FIG. 12 (step S23). Further, the electrical angle of the electric motor 5 is obtained with reference to the table 15d of FIG. 3 (step S25). Then, the electrical angle detection process is terminated and the process returns to the flowchart of FIG.

  After completion of the electrical angle detection process in step S3 shown in FIG. 14, the motor control unit 15b performs an evaluation process (step S5). In the evaluation process of step S5, the motor control unit 15b determines whether the electrical angle detected in step S3 matches the electrical angle corresponding to the rotation angle at which the rotor 5b stops only when the electric compressor 1 is mechanically locked. Confirm whether or not.

  In the present embodiment, the memory 15c of the motor control unit 15b shown in FIG. 3 stores an electrical angle database 15e corresponding to the rotation angle at which the rotor 5b stops only when the electric compressor 1 is mechanically locked. ing.

  In the present embodiment, the database 15e is stored in the memory 15c as shown in FIG. 5 in which the rotor 3e is stopped by the rotational frictional force between the vane 33 and the inner peripheral surface of the cylinder chamber 3d. This is the electrical angle of the stop position of the rotor 5b existing at the location.

  Therefore, when the electric motor 5 stops due to step-out or when the compressor 1 stops normally due to the energization stop of the electric motor 5, as shown in the explanatory diagram of FIG. The rotor 3e does not stop at the rotation angle. If the rotor 3e stops at a rotation angle other than the electrical angle of the database 15e, it is nothing but the rotor 3e stopped due to the mechanical lock of the compressor 1 being generated. Therefore, the evaluation process in step S5 is performed by confirming whether or not the rotation angle of the database 15e matches.

  After the evaluation process in step S5, the motor control unit 15b checks whether or not the occurrence of mechanical lock of the electric compressor 1 has been detected (step S7). Here, in the evaluation process of step S5, if the electrical angle detected in step S3 does not match the electrical angle of the database 15e in the memory 15c, it means that the occurrence of lock is detected, and if it matches, the occurrence of lock is detected. It will not be.

  If no occurrence of lock has been detected (NO in step S7), the motor control unit 15b determines that no lock has occurred (step S9), and ends the series of processes. If the occurrence of a lock is detected (YES in step S7), it is determined that a lock has occurred (step S11), and the series of processing ends.

  As is clear from the above description, in the present embodiment, step S23 in the flowchart of FIG. 15 is processing corresponding to the shaft current detecting means in the claims. Moreover, in this embodiment, step S25 in FIG. 15 is a process corresponding to the electrical angle detection means in the claims.

  Furthermore, in this embodiment, step S7 in the flowchart of FIG. 14 is a process corresponding to the lock detecting means in the claims.

  Thus, according to the controller 15 of this embodiment, when the compressor 1 in operation stops, a current flows through the coils 5d of the respective phases of the stator 5c for a very short time such that the rotor 5b does not rotate. The α-axis current iα and β-axis current iβ are obtained from the currents (iu, iv, iw) flowing through the coils 5d of each phase, and the electrical angle of the electric motor 5 is referred to by referring to the table 15d from the combination of the values. I asked for.

  Then, the obtained electrical angle is a rotation angle other than the rotation angle of the database 15e stored in the memory 15c of the motor control unit 15b, which is stopped only when the compressor 1 is stopped due to step-out of the electric motor 5 or stop of energization. If the electrical angle is a corresponding one, it is determined that a mechanical lock has occurred in the compressor 1.

  For this reason, it is possible to suppress power consumption only by executing a simple logic of energizing the coils 5d of each phase of the stator 5c of the electric motor 5 for a short time to detect the electrical angle and collate it with the electrical angle of the database 15e. It can be detected that a mechanical lock has occurred in the compressor 1.

  In the above-described embodiment, the electrical angle detected in step S3 is collated with the electrical angle in the database 15e to detect the occurrence of mechanical lock of the electric compressor 1. However, without using the database 15e, the step S3 is performed. It is also possible to detect the occurrence of mechanical lock of the electric compressor 1 using the electrical angle detected in step (b).

  Hereinafter, another embodiment of the present invention that performs lock detection as described above will be described with reference to FIG. FIG. 17 is a flowchart showing a processing procedure when the motor control unit 15b determines the cause when the electric compressor according to another embodiment of the present invention stops during operation. The motor control unit 15b periodically and repeatedly executes the process of the flowchart shown in FIG.

  Then, the motor control unit 15b first checks whether or not the operating electric compressor 1 has stopped (step S1), similarly to the procedure shown in the flowchart of FIG. 14, and if not stopped (in step S1) NO), a series of processing ends.

  On the other hand, when the operating electric compressor 1 is stopped (YES in step S1), the motor control unit 15b performs a process of detecting the electrical angle of the rotor 5b of the electric motor 5 (step S3). Here, the electrical angle detection process performed by the motor control unit 15b is the process described with reference to the flowchart of FIG.

  And after completion | finish of the electrical angle detection process of step S3, the motor control part 15b performs the forced commutation operation | movement of the electric motor 5 which makes the coil 5d of each phase flow the confirmation electric current for forcibly rotating the rotor 5b. This is performed for a certain period (step S13).

  Note that the period during which the forced commutation operation is performed in step S13 may be, for example, a period in which the rotor 5b rotates about 50 ° to 60 ° in terms of control based on the electrical angle of the rotor 5b detected in step S3.

  Further, in the forced commutation operation in step S13, a confirmation current may be caused to flow in each phase coil 5d in the energization direction (direction in which the electrical angle increases) when the compressor 1 is normally operated. However, the confirmation current may be caused to flow through the coil 5d of each phase in the energization direction opposite to the energization direction of the normal operation.

  That is, when the compressor 1 is stopped by stopping energization of the electric motor 5, the rotor 3e rotates in the reverse direction (reverse rotation) due to the differential pressure between the refrigerant pressure in the discharge chamber 7a and the refrigerant pressure in the suction chamber 7b. The reverse rotation of the rotor 3e stops when the rotational frictional force (vane friction) between the vane 33 and the inner peripheral surface of the cylinder chamber 3d exceeds the differential pressure between the refrigerant pressure in the discharge chamber 7a and the refrigerant pressure in the suction chamber 7b. .

  For this reason, if the forced commutation operation in step S13 causes the confirmation current to flow in the coils 5d of each phase in the direction opposite to the energization direction when the compressor 1 is normally operated, the refrigerant pressure in the discharge chamber 7a is increased. Even in a state where the refrigerant pressure in the suction chamber 7b is higher than the refrigerant pressure in the suction chamber 7b before being equalized with the refrigerant pressure in the suction chamber 7b, the rotor 3e can be easily forcibly rotated with a small confirmation current.

  After the forced commutation operation in step S13, the motor control unit 15b performs a process for detecting the electrical angle of the rotor 5b of the electric motor 5 (step S15). This electrical angle detection process is performed with the contents shown in FIG. 15 as in the electrical angle detection process performed in step S3.

  After completion of the electrical angle detection process in step S15 shown in FIG. 17, the motor control unit 15b performs an evaluation process (step S17). In the evaluation process in step S17, the motor control unit 15b matches the electrical angle detected in step S15 after the forced commutation process in step S13 with the electrical angle detected in step S3 before the forced commutation process in step S13. , Done by checking the discrepancy.

  After the evaluation process in step S17, the motor control unit 15b checks whether or not the occurrence of mechanical lock of the electric compressor 1 is detected (step S19). Here, in the evaluation process of step S17, if the electrical angles detected in step S3 and step S15 match, it means that the occurrence of lock has been detected. If not, the occurrence of lock has not been detected. become.

  If no occurrence of lock is detected (NO in step S19), the motor control unit 15b determines that no lock is generated (step S21), and ends the series of processes. If the occurrence of a lock is detected (YES in step S19), it is determined that a lock has occurred (step S23), and the series of processing ends.

  As is clear from the above description, in the present embodiment, step S19 in the flowchart of FIG. 17 is processing corresponding to the lock detecting means in the claims. Moreover, in this embodiment, step S13 in FIG. 17 is a process corresponding to the forced rotation means in the claims.

  Thus, according to the controller 15 of this embodiment, when the compressor 1 in operation stops, a current flows through the coils 5d of the respective phases of the stator 5c for a very short time such that the rotor 5b does not rotate. Thus, the α-axis current iα and the β-axis current iβ are obtained from the currents (iu, iv, iw) flowing through the coils 5d of each phase, and the electrical angle of the electric motor 5 is obtained from the combination of the values.

  Then, after energizing the confirmation current for forcibly commutating the rotor 5b of the electric motor 5, the electric angle of the electric motor 5 is obtained by the same method as when the motor is stopped. Judged that a mechanical lock occurred.

  For this reason, it is possible to suppress power consumption only by confirming whether or not the mechanical lock has occurred in the compressor 1 due to the coincidence or mismatch of the electrical angles before and after the forced commutation process detected in step S3 and step S15, respectively. However, it is possible to detect that a mechanical lock has occurred in the compressor 1.

  In this embodiment, it is not necessary to store the database 15e in the memory 15c.

  Note that, as a result of step S7 in the flowchart of FIG. 14, if the occurrence of lock is not detected (NO in step S7), the processing after step S13 of FIG. 17 may be continuously performed.

  In the present embodiment, the case where the present invention is applied to the electric compressor 1 having the vane rotary type compression mechanism 3 that rotates the rotor 3e in the cylinder chamber 3d has been described as an example. However, the present invention has a rotary compression mechanism that sucks and compresses gas by rotating a rotating body, such as a scroll compressor that rotates a movable scroll with respect to a fixed scroll to compress gas. This is widely applicable when the compressor is rotated by a motor.

  The present invention can be used in an electric compressor in which a refrigerant compression mechanism is rotated by an electric motor.

1 Electric compressor (compressor)
3 Compression mechanism 3a, 3b Side block 3c Cylinder block 3d Cylinder chamber 3e Rotor (rotating body)
3f, 3g Bearing part 3h, 3i, 3j, 3k Passage 3l Discharge port 3m Discharge valve 5 Electric motor (motor)
5a Rotating shaft 5b Rotor (rotor)
5c Stator 5d Coil 7 Housing 7a Discharge chamber 7b Suction chamber 7c Opening 7d Oil reservoir 7e Oil separator 9 Lid 11 Lubricating oil 13 DC power supply 15 Controller (control device, compressor motor control device)
15a Inverter circuit 15b Motor controller (shaft current detection means, electrical angle detection means, lock detection means, forced rotation means)
15c memory (storage means)
15d table 15e database 31 vane groove 33 vane 35 compression chamber iα α-axis current iβ β-axis current Q1 to Q6 IGBT
X direction of rotation

Claims (6)

In the control device (15) of the motor (5) for rotating the rotating shaft (5a) connected to the rotating body (3e) of the compression mechanism (3) of the compressor (1) in which the sucked gas is compressed,
While the motor (5) is stopped, the coil (5d) of the motor (5) is energized with a position detection current, and the stator (5c) of the motor (5) is obtained from the current flowing through the coil (5d). An axis current detection means (15b) for detecting an axis current (iα, iβ) in an orthogonal coordinate system corresponding to the electrical angle of the rotor (5b) of the motor (5) with reference to the position of
Electrical angle detection means (15b) for detecting the electrical angle corresponding to the shaft current (iα, iβ) detected by the shaft current detection means (15b);
Lock detection means (15b) for evaluating the electrical angle detected by the electrical angle detection means (15b), and detecting from the result of the evaluation that a mechanical lock of the compressor (1) has occurred;
A compressor motor control device (15).   And further comprising a storage means (15c) for storing a database (15e) relating to the electrical angle corresponding to a rotation angle at which the rotor (5b) stops only when mechanical compression of the compressor (1) occurs. The compressor according to claim 1, wherein the means (15b) detects that the lock has occurred from a result of evaluating the electrical angle detected by the electrical angle detection means (15b) against the database (15e). Motor control device (15).   The compression mechanism (3) is protruded from a plurality of positions at equal intervals in the rotation direction (X) of the rotating body (3e), and the rotating body (3e) rotates inside the cylinder chamber (3d). In the compression chamber (35) between the vanes (33) that are in sliding contact with the peripheral surface, the gas sucked into the cylinder chamber (3d) is compressed, and the storage means (15c) is configured to store the rotating body (3e). The compressor motor control device (15) according to claim 2, wherein the electric angle corresponding to a rotation angle at a position where the rotation is stopped by a rotational frictional force with the inner peripheral surface of the cylinder chamber (3d) is stored as the database (15e). .   The lock detecting means (15b) is a forced rotating means for forcibly rotating the rotor (5b) by supplying a current for confirmation to the rotor (5b) after the electrical angle is detected by the electrical angle detecting means (15b). (15b) corresponding to the shaft current (iα, iβ) detected by the shaft current detection means (15b) while the motor (5) is stopped after the forced rotation by the forced rotation means (15b). The evaluation of the electrical angle detected by the electrical angle detection means (15b) and the electrical angle detected by the electrical angle detection means (15b) before the forced rotation by the forced rotation means (15b) The lock has occurred when the electrical angles detected by the electrical angle detection means (15b) are the same before and after the forced rotation by the forced rotation means (15b). The compressor motor control device (15) according to claim 1, wherein   The compressor motor control device (15) according to claim 4, wherein the forced rotation means (15b) forcibly rotates the rotor (5b) in a direction opposite to that during operation of the compressor (1). A compression mechanism (3) in which the sucked gas is compressed by the rotation of the rotating body (3e);
A motor (5) for rotating a rotating shaft (5a) connected to the rotating body (3e);
A control device (15) for controlling the motor (5),
The compressor motor control device (15) according to claim 1, 2, 3, 4 or 5 is used as the control device (15).
Electric compressor (1).

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