JP2017212794A - Compressor motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accelerate a motor of an electric compressor motor after start-up without a loss of synchronism by increasing a command speed in synchronous control.SOLUTION: A command speed that is set by a motor control part 15b is temporarily linearly increased after start-up of an electric motor 5, changed from acceleration to deceleration at a certain time point and returned to acceleration after the lapse of a fixed period. Thus, when a phase advance amount of a command angle to a real motor angle of the electric motor 5 is increased, a motor torque TM of the electric motor 5 is increased more as the phase advance amount (=current phase) is increased more. Therefore, even if the motor torque TM becomes less than a load torque TL and the advancement of the real motor angle is temporarily delayed in relative to advancement of the command angle of the electric motor 5, the motor torque TM is increased in such a manner that the motor torque becomes sufficiently more than the load torque TL during a fixed period in which the command speed is reduced. Thus, the subsequent phase advance amount of the command angle relative to the real motor angle of the electric motor 5 is decreased and a loss of synchronism in the electric motor 5 can be prevented.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a motor control device that rotates a compressor.

  For example, in a compressor used in a refrigeration cycle, a rotor in a cylinder is rotated to compress fluid sucked into the cylinder chamber and discharged outside the cylinder chamber. In an electric compressor that rotates a rotor with a motor, the rotation angle of the rotor is detected sensorlessly using the induced current flowing through the stator coil of the motor and applied to the stator coil of the motor according to the detected rotation angle of the rotor. Sensorless vector control for adjusting the voltage to be performed is performed.

  However, the induced current flowing through the stator coil at the start of the motor is weak because the amount of rotation of the rotor is small, and may be insufficient to specify the rotation angle of the rotor. Therefore, at the time of starting the motor, the rotor is forcibly rotated by rotating the motor by synchronous control for forcibly moving the pole excited by the stator coil at a constant frequency.

  However, when the motor is started, the load torque applied to the rotor may be large due to the differential pressure in the compressor. If the motor is started by synchronous control in this state, the current flowing through the stator coil is insufficient with respect to the load torque applied to the rotor. As a result, the motor torque exceeding the load torque is not generated, and the motor may fail to start.

  Therefore, it has been proposed to increase the motor torque by setting the command speed, which is the target speed for motor control, to be higher for a certain period from the start of the motor (for example, Patent Document 1).

JP 2009-225510 A

  By the way, the motor after starting is accelerated toward a rotational speed at which the rotational angle of the rotor can be detected by gradually increasing the command speed. At this time, the motor torque and the load torque respectively increase and decrease depending on the rotation angle of the rotor, and there is a period in which the motor torque is lower than the load torque.

  During the period when the motor torque is lower than the load torque, the progress of the actual angle of the rotor is delayed with respect to the progress of the command angle of the motor according to the command speed that gradually increases. When this delay increases and the motor current phase advances, the motor torque continues to decrease without increasing again, and as a result, the rotor stalls and the motor steps out.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a compressor motor control device capable of accelerating a motor of an electric compressor after starting without stepping out due to an increase in command speed in synchronous control. There is to do.

In order to achieve the above object, a compressor motor control device according to an aspect of the present invention includes:
When the rotational speed of the rotor of the motor that rotates the compression mechanism of the compressor that compresses the sucked gas is accelerated to a predetermined speed at which the rotational angle of the rotor can be detected from information such as current and voltage of the motor, synchronous control is performed. In the control device for switching from sensorless vector control to rotating the rotor,
During the period of the synchronous control, a command speed that is a target rotational speed in the control of the rotor is changed from acceleration to deceleration for a certain period, and the command speed is returned from deceleration to acceleration after the lapse of the certain period. Control means to perform,
During the period of the synchronous control, the motor current phase corresponding to the phase advance amount of the target angle of control of the rotor relative to the actual angle of the rotor is stepped out during the period of the synchronous control. It starts and ends at the timing when the step-out limit amount is equal to or less (however, the step-out limit amount ≧ 0).

  According to the present invention, the motor of the electric compressor after the start can be accelerated without being stepped out due to an increase in the command speed in the synchronous control.

It is sectional drawing which shows the electric compressor carrying the electric motor controlled by the compressor motor control apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which shows the electrical structure of the electric compressor of FIG. 2 is a graph showing an example of a change with time of an actual motor speed (actual speed) that is an actual rotational speed of a rotor when a command speed of the electric motor of FIG. 1 is linearly accelerated from the start. It is a graph which shows the time-dependent change of the motor torque of the electric motor and the load torque of an electric motor which generate | occur | produce when the electric current according to the command speed of FIG. 3 flows through the coil of each phase. Time course of the rotation angle (actual motor angle) of the rotor that rotates in accordance with the relationship between the motor torque and the load torque in FIG. 4 and the command angle of the electric motor that is the rotation angle in the control of the rotor corresponding to the command speed in FIG. It is a graph which shows a change. 6 is a graph showing a temporal change of a current phase that is a phase of a command angle based on an actual motor angle (actual angle) in FIG. 5 and a correlation between the current phase and the motor torque. FIG. 1 shows how the actual motor speed (actual speed) changes from the start when the motor control unit in FIG. It is a graph to show. It is a graph which shows the time-dependent change of the motor torque of the electric motor and the load torque of an electric motor which generate | occur | produce when the electric current according to the command speed of FIG. 7 flows through the coil of each phase. The time of the rotation angle (actual motor angle) of the rotor rotating in accordance with the relationship between the motor torque and the load torque in FIG. 8 and the command angle of the electric motor, which is the rotation angle in the control of the rotor corresponding to the command speed in FIG. It is a graph which shows a change. 10 is a graph showing a change with time of a current phase that is a phase of a command angle based on an actual motor angle (actual angle) in FIG. 9.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an electric compressor equipped with an electric motor controlled by a compressor motor control device according to an embodiment of the present invention. 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 side blocks 3a and 3b. A plurality of vane grooves (not shown) are opened in the peripheral surface of the rotor 3e, and vanes (not shown) that can be projected and retracted from the peripheral surface of the rotor 3e are supported in the respective vane grooves.

  When the rotor 3e is rotated in the cylinder chamber 3d by the electric motor 5, each vane of the rotor 3e protrudes and disappears from the vane groove along the inner peripheral surface of the cylinder chamber 3d, and the two vanes adjacent to the rotor 3e and the cylinder chamber The volume of the space constituted by 3d changes.

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

  The electric motor 5 (corresponding to the motor in the claims) is, for example, a three-phase AC motor, and includes a rotor 5b attached to the rotating shaft 5a and a stator 5c disposed outside the rotor 5b. The stator 5c has teeth (not shown) corresponding to a plurality of poles. A coil 5d is wound around each tooth. There are a plurality of coils 5d for each phase. In the present embodiment, a plurality of coils 5d for each phase are connected in parallel. Of course, the coils 5d for each phase may be connected in series.

  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.

  In this embodiment, the rotor 5b is of an embedded magnet type (IPM: Interior permanent Magnet) in which a permanent magnet is embedded. Therefore, the motor torque of the electric motor 5 is a combination of the magnet torque and the reluctance torque.

  In general, the magnet torque of an IPM motor is represented by a cosine wave (cos) waveform, and has a maximum value at a current phase = 0 deg. The reluctance torque is represented by a sine wave (sin) waveform and has a maximum value at a current phase = 45 deg. Therefore, the motor torque obtained by synthesizing the magnet torque and the reluctance torque of the electric motor 5 has a maximum value in the range of current phase = 0 to 45 deg.

  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.

  FIG. 2 is an explanatory diagram showing an electrical configuration of the electric compressor 1. As shown in FIG. 2, the controller 15 (corresponding to the compressor motor control device in the claims) has an inverter circuit 15a and a motor control unit 15b.

  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 control means in the claims) controls voltage application to each coil 5d in a predetermined pattern for generating a rotating magnetic field in the stator 5c of the electric motor 5. Consists of a computer. The motor control unit 15b has a memory 15c (corresponding to storage means in claims) that stores various data, tables, formulas used for control, and the like.

  As an alternative to the actual motor angle, the motor control unit 15b calculates the rotation angle of the rotor 5b as an actual motor angle (actual angle) from information such as the voltage and current of the motor. Then, sensorless vector control is performed to adjust the phase of the current flowing through the coil 5d in accordance with the calculated actual motor angle.

  However, the induced voltage generated in each coil 5d when the electric compressor 1 is started by the electric motor 5 is weak because the amount of rotation of the rotor 5b is small, and it is not possible for the motor control unit 15b to detect the actual motor angle. May be sufficient. If the actual motor angle cannot be detected, it is difficult for the motor control unit 15b to adjust the phase of the current flowing through the coil 5d so that a motor torque corresponding to the load torque of the rotor 5b is generated.

  Therefore, when the electric compressor 1 is started, the electric motor 5 is forcibly rotated by synchronous control until the rotational speed of the rotor 5b increases to a speed at which the actual motor angle can be detected (corresponding to a predetermined speed in the claims). . In the synchronous control, a rotating magnetic field is generated in the stator 5c with a preset frequency pattern, and the rotor 5b is forcibly rotated by rotating the rotor 5b with the rotating magnetic field.

  When the rotational speed of the rotor 5b increases to some extent and an induced voltage sufficient to detect the rotational angle of the rotor 5b is generated, the motor control unit 15b switches the control of the electric motor 5 from synchronous control to sensorless vector control. .

  By the way, in the synchronous control, the motor control unit 15b makes a current (phase) that flows through the coil 5d of each phase so that the motor torque surely exceeds the load torque of the rotor 5b and the rotor 5b reliably follows the rotating magnetic field. It is important to set the value of (current).

  Here, the value of the current flowing through the coil 5d of each phase is set based on the command speed of the electric motor 5 in the synchronous control. Accordingly, a case is considered where the command speed is gradually accelerated from the start of the electric motor 5 toward the rotation speed at which the motor control unit 15b detects the actual motor angle (rotation angle of the rotor 5b) and can be switched to sensorless vector control. .

  FIG. 3 is a graph showing an example of the change over time in the actual motor speed (actual speed) that is the actual rotational speed of the rotor 5b when the command speed of the electric motor 5 is linearly accelerated from the start. In FIG. 3, the broken line indicates the command speed of the electric motor 5, and the solid line indicates the actual motor speed (actual speed).

  FIG. 4 is a graph showing changes over time in the motor torque of the electric motor 5 and the load torque of the electric motor 5 that are generated when a current corresponding to the command speed in FIG. 3 flows through the coil 5d of each phase. In FIG. 4, the broken line indicates the load torque TL of the electric motor 5, and the solid line indicates the motor torque TM.

  FIG. 5 shows the rotation of the rotor 5b that rotates in accordance with the relationship between the command angle of the electric motor 5, which is the rotation angle in the control of the rotor 5b corresponding to the command speed of FIG. 3, and the motor torque and load torque TL of FIG. It is a graph which shows a time-dependent change with an angle (actual motor angle). In FIG. 5, the broken line indicates the command angle of the electric motor 5, and the solid line indicates the actual motor angle (actual angle).

  FIG. 6 is a graph showing the change over time in the current phase, which is the phase of the command angle based on the actual motor angle (actual angle) in FIG. 5, and a graph showing the relationship of the motor torque TM with respect to the current phase.

  Then, as indicated by the broken line in the graph of FIG. 3, when a current corresponding to the linearly accelerated command speed set by the motor control unit 15b flows through the coil 5d of each phase, the solid line and As indicated by broken lines, the motor torque TM and the load torque TL increase or decrease depending on the rotation angle of the rotor 5b. Since there is a phase difference between the increase / decrease in the motor torque TM and the increase / decrease in the load torque TL, there is also a period in which the motor torque TM is lower than the load torque TL as shown in the portion surrounded by the frame I in FIG. To do.

  In the period of the frame line I in FIG. 4 in which the motor torque TM is lower than the load torque TL, as shown in the graph of FIG. 5, the electric motor 5 that is the rotational angle in control of the rotor 5b corresponding to the command speed that gradually increases The actual rotation angle of the rotor 5b, that is, the actual motor angle is delayed with respect to the command angle.

  When this delay is expanded as shown in the portion surrounded by the frame line II in FIG. 5, the current phase corresponding to the phase of the command angle based on the actual motor angle of the electric motor 5 shown in the graph of FIG. As time passes, the process proceeds greatly as shown by the portion surrounded by the frame line III in FIG.

  When the current phase of the electric motor 5 greatly advances, the motor torque corresponding to the current phase as shown in the portion surrounded by the frame IV in the graph of the correlation between the current phase and the motor torque TM shown in an overlapped manner in FIG. TM decreases beyond the maximum value. Then, even if time passes and the rotation angle of the rotor 5b (actual angle of the electric motor 5) increases, the motor torque TM does not increase enough to exceed the load torque TL.

  Therefore, when the motor torque TM changes from increasing to decreasing, the subsequent motor torque TM continues to decrease without increasing again, as shown in the portion surrounded by the frame line V in FIG. As indicated by a solid line in FIG. 3, the rotor 5b stalls and the electric motor 5 steps out and stops.

  However, if the current phase of the electric motor 5 is kept within a certain phase range, the motor torque TM is maintained at a somewhat high value as can be seen from the graph showing the correlation between the current phase and the motor torque TM in FIG. be able to.

  Therefore, a control pattern of the electric motor 5 performed during the period of the synchronous control by the motor control unit 15b of the controller 15 of the present embodiment will be described below.

  FIG. 7 is a graph showing the change over time from the start of the actual motor speed (actual speed) in the acceleration control of the electric motor 5 performed by the motor control unit 15b. In FIG. 7, the broken line indicates the command speed of the electric motor 5, and the solid line indicates the actual motor speed (actual speed).

  FIG. 8 is a graph showing temporal changes in the motor torque TM of the electric motor 5 and the load torque TL of the electric motor 5 that are generated when a current corresponding to the command speed in FIG. 7 flows through the coil 5d of each phase. In FIG. 8, the broken line shows the load torque TL of the electric motor 5, and the solid line shows the motor torque TM.

  FIG. 9 shows the command angle of the electric motor 5, which is the control rotation angle of the rotor 5b corresponding to the command speed in FIG. 7, and the relationship between the motor torque TM and the load torque TL in FIG. It is a graph which shows a time-dependent change with a rotation angle (actual motor angle). In FIG. 9, the broken line indicates the command angle of the electric motor 5, and the solid line indicates the actual motor angle (actual angle).

  FIG. 10 is a graph showing the change over time of the current phase corresponding to the phase of the command angle based on the actual motor angle (actual angle) of FIG.

  Then, as indicated by a broken line in the graph of FIG. 7, the command speed set by the motor control unit 15 b is linearly accelerated once the electric motor 5 is started, and is indicated by a portion surrounded by a frame line VI in FIG. 7. Thus, the acceleration is once changed from deceleration to deceleration at a certain time (in the example of FIG. 7, when 0.04 sec has elapsed after the start).

  Until the command speed is changed to deceleration, the motor torque TM and the load torque TL of the electric motor 5 in which the current corresponding to the command speed linearly accelerated flows through the coil 5d of each phase are shown in the graph of FIG. As indicated by the solid line and the broken line, respectively, it is increased or decreased depending on the rotation angle of the rotor 5b.

  Since there is a phase difference between the increase / decrease in the motor torque TM and the increase / decrease in the load torque TL, in the acceleration period until the command speed is changed to the deceleration, the frame line VI in FIG. As shown in the portion of elapsed time corresponding to the portion surrounded by, there is also a period in which the motor torque TM is lower than the load torque TL.

  During the period when the motor torque TM is lower than the load torque TL, the actual motor angle progresses with respect to the progress of the command angle of the electric motor 5, which is the rotational angle on the control of the rotor 5b corresponding to the command speed that gradually increases. 9 is delayed as indicated by the portion surrounded by the frame line VII in the graph.

  Therefore, this delay increases, and the current phase corresponding to the phase of the command angle based on the actual motor angle of the electric motor 5 becomes the phase Ptp in which the motor torque TM becomes the maximum value and turns from increase to decrease (in claims) Before the torque peak current phase increases to 40 deg) in the correlation shown in the graph of FIG. 6, the motor control unit 15b decelerates the command speed from acceleration to acceleration as indicated by the portion surrounded by the frame line VI in FIG. Change to

  When the phase delay of the actual motor angle with respect to the progress of the command angle is reduced to some extent, the motor control unit 15b returns from the decrease again to the increase before the command speed becomes “0”, and switches from synchronous control to sensorless vector control. The command speed is linearly accelerated to a predetermined speed with an acceleration larger than the linear acceleration immediately after the start.

  Here, in the present embodiment, the start and end of the fixed period in which the command speed is once decelerated during the period of the synchronous control is as shown in the graph of FIG. 10 during the period of the synchronous control. The motor torque TM corresponding to the current phase advances is determined so as to fall within a range.

  For example, this range corresponds to a range of −50 to 40 degrees in the correlation shown in the graph of FIG. 6. However, here, since it is premised that the progress of the actual motor angle is delayed (the phase is delayed) with respect to the progress of the command angle of the electric motor 5, the above-described range of −50 to 40 degrees Excluding the negative value range is a more appropriate range as the current range of the current phase referred to here.

  Therefore, in the present embodiment, the delay of the progress of the actual motor angle relative to the progress of the command angle of the electric motor 5 is 0 to 40 degrees in the correlation shown in the graph of FIG. The phase amount is within the range of. Therefore, in this embodiment, the step-out limit amount in the claims is 40 deg.

  Note that the step-out of the electric motor 5 due to the increase in the delay of the actual motor angle with respect to the command angle of the electric motor 5 and the progress of the current phase causes the load torque TL of the electric motor 5 to peak (maximum value). It is easy to happen when you meet. Then, the inflection point P in FIG. 8 at which the load torque TL of the electric motor 5 first changes from increasing to decreasing after starting comes when the time exceeds 0.05 sec after starting the electric motor 5.

  However, in the example of FIG. 7, the motor control is performed when 0.04 sec or more has elapsed after the start of the electric motor 5 sufficiently before the load torque TL of the electric motor 5 reaches the inflection point P of FIG. The command speed set by the unit 15b is changed from acceleration to deceleration. Therefore, the timing at which the command speed is changed from acceleration to deceleration may be slightly delayed so as to be the time immediately before the load torque TL of the electric motor 5 reaches the inflection point P in FIG.

  As a result, the command speed is decelerated before the current phase progresses so that the step-out occurs, and the step-out is surely prevented, and as much as possible from the start of the electric motor 5 until the command speed is changed to the deceleration. The timing at which the electric motor 5 is accelerated to switch from synchronous control to sensorless vector control can be advanced.

  In addition, in the acceleration control pattern of the electric motor 5 performed by the motor control unit 15b, the start and end timings of the fixed period for decelerating the command speed are experimentally determined in advance according to the characteristics of the electric motor 5. It may be obtained and stored in the memory 15c of the controller 15.

  In that case, when the motor control unit 15b synchronously controls the electric motor 5, the acceleration control pattern is read from the memory 15c and executed, and during the period from the start to the switch to the sensorless vector control, The command speed can be temporarily switched from linear acceleration to linear deceleration at an appropriate timing, and then returned to linear acceleration again from deceleration.

  When the motor control unit 15b performs the acceleration control as described above, even if the motor torque TM and the load torque TL of the electric motor 5 are increased or decreased at different phases depending on the rotation angle of the rotor 5b, the actual motor of the electric motor 5 is obtained. When the phase advance amount of the command angle with respect to the angle increases, the motor torque TM of the electric motor 5 can be increased more as the phase advance amount (= current phase) increases.

  Therefore, even if the motor torque TM falls below the load torque TL and the progress of the actual motor angle is temporarily delayed with respect to the progress of the command angle of the electric motor 5, the load torque is reduced during a certain period in which the command speed is decelerated. The motor torque TM can be increased so as to sufficiently exceed TL, and the phase advance amount of the command angle with respect to the actual motor angle of the electric motor 5 thereafter can be decreased.

  As a result, the phase advance amount of the command angle with respect to the actual motor angle of the electric motor 5 is always kept below the step-out limit amount that the electric motor 5 will step out (however, the step-out limit amount ≧ 0) during the synchronous control period. Thus, it is possible to prevent the electric motor 5 from stepping out during the synchronous control.

  In the present embodiment, the acceleration period after deceleration for a certain period (corresponding to the second acceleration period in the claims) rather than the acceleration period before deceleration for a certain period (corresponding to the first acceleration period in the claims). Equivalent), the acceleration when accelerating the command speed of the electric motor 5 is increased. As a result, it is possible to prevent the electric motor 5 from taking a long time to reach a predetermined speed at which switching to the sensorless vector control is performed by reducing the command speed for a certain period.

  However, as long as the phase advance amount of the command angle with respect to the actual motor angle of the electric motor 5 can always be maintained below the step-out limit amount during the period of the synchronous control, the acceleration in the acceleration period before the deceleration and the acceleration period after the deceleration are constant. May be the same acceleration or different accelerations (either one may be higher than the other).

  Further, in the present embodiment, the range in which the corresponding motor torque TM increases as the current phase advances through the period of the synchronous control during the current phase of the electric motor 5 (for example, 0 to 40 deg in the correlation shown in the graph of FIG. 6). Range), the start and end of a certain period during which the command speed is once decelerated during the synchronous control period.

  However, as long as the phase advance amount of the command angle with respect to the actual motor angle of the electric motor 5 can always be kept below the step-out limit amount during the period of the synchronous control, for example, the phase exceeding 40 deg in the correlation shown in the graph of FIG. The upper limit of the step-out limit amount may be a range wider than the range described in the present embodiment.

  Furthermore, in the present embodiment, the case where the electric motor 5 is an IPM motor using an interior permanent magnet (IPM) rotor 5b in which a permanent magnet is embedded has been described. However, for example, an SPM motor using a surface permanent magnet (SPM) rotor 5 b in which a permanent magnet is exposed on the surface may be used for the electric motor 5.

  In that case, although the characteristics of the motor torque TM are different from the characteristics of the IPM motor shown in FIG. 6, the start and end timings of a certain period for once decelerating the command speed of the electric motor 5 are determined in accordance with the characteristics. Good.

  In the above 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 driven by an electric motor.

1 Electric compressor (compressor)
3 Compression mechanism 3a, 3b Side block 3c Cylinder block 3d Cylinder chamber 3e Rotor 5 Electric motor (motor)
5a Rotating shaft 5b Rotor 5c Stator 5d Coil 7 Housing 7a Discharge chamber 7b Suction chamber 7c Open 9 Lid 13 DC power supply 15 Controller (compressor motor control device)
15a Inverter circuit 15b Motor controller (control means)
15c memory (storage means)
P Load torque inflection point Ptp Current phase at which motor torque is maximum (current phase of torque peak)
TL Load torque TM Motor torque Q1-Q6 IGBT (Insulated gate bipolar transistor)

Claims (5)

The rotational speed of the rotor (5b) of the motor (5) that rotates the compression mechanism (3) of the compressor (1) in which the sucked gas is compressed is determined based on information such as current and voltage of the motor (5). In the control device (15) for rotating the rotor (5b) by switching from synchronous control to sensorless vector control when accelerated to a predetermined speed capable of detecting the rotation angle of 5b)
During the period of the synchronous control, the command speed, which is the target rotational speed for controlling the rotor (5b), is changed from acceleration to deceleration for a certain period, and the command speed is returned from deceleration to acceleration after the lapse of the certain period. A control means (15b) for performing acceleration control;
During the period of the synchronous control, the current phase of the motor (5), which is the phase advance amount of the target angle on the control of the rotor (5b) with respect to the actual angle of the rotor (5b), is the period of the synchronous control. Through and at the timing when the motor (5) is below the step-out limit amount (step-out limit amount ≧ 0).
Compressor motor control device (15).   2. The compressor motor according to claim 1, wherein the fixed period is started before the inflection point at which the load torque (TL) of the motor (5) first changes from increasing to decreasing after the motor (5) is started. Control device (15).   The step-out limit amount is defined as a torque peak current phase (Ptp) when the current phase at which the motor torque (TM) of the motor (5) corresponding to the current phase of the motor (5) is a maximum value is set. The compressor motor control device (15) according to claim 1 or 2, wherein a phase amount is equal to or less than a current phase (Ptp) of the torque peak.   The said control means (15b) is an acceleration higher than the 1st acceleration period before the said fixed period, and accelerates the said command speed in the 2nd acceleration period after the said fixed period progress. Compressor motor control device (15).   The compressor motor control device (15) according to claim 1, 2, 3 or 4, wherein the control means (15b) performs the acceleration control with an acceleration and deceleration pattern of the command speed stored in the storage means (15c).

Images