JP4509010B2 - Permanent magnet synchronous motor control apparatus and method, and program - Google Patents

Description

  The present invention relates to control of a permanent magnet type synchronous motor used as a drive source of a compressor included in an in-vehicle air conditioner.

An electric compressor used for an in-vehicle air conditioner realizes a cooling function by compressing a refrigerant by using a rotational force transmitted from a built-in or coupled permanent magnet type synchronous motor. Control of the motor in such an electric compressor is so-called sensorless control, because control using a position sensor such as a Hall element cannot be performed because the interior in which the motor is housed is immersed in lubricating oil. .
By the way, in the sensorless control of the permanent magnet type synchronous motor, since the rotor position is unknown at the time of starting the electric motor, the synchronous operation cannot be performed immediately. Therefore, conventionally, a three-phase voltage (current) for rotating the rotor at a certain speed in a certain direction for a certain time is output to the motor and forcibly started (see, for example, Patent Document 1). .)
JP 2003-28073 A

  However, as described above, if control is performed such that a constant current flows unilaterally without grasping the state of the compressor linked to the motor, the possibility of starting failure increases. Considering an electric compressor as a product, it is preferable to eliminate as many startup failures as possible. In particular, since hybrid vehicles, FCEVs, HEVs, and the like drive wheels using a fixed battery as a power source, it has been required to avoid power consumption due to failure in starting an electric compressor that uses the same power source as much as possible.

  The present invention has been made to solve the above-described problem, and a permanent magnet type synchronous motor control device capable of smoothly starting a permanent magnet type synchronous motor used for driving a compressor of an in-vehicle air conditioner. And a method and program.

In order to solve the above problems, the present invention employs the following means.
The present invention is a control device for a permanent magnet type synchronous motor used as a drive source of a compressor of an in-vehicle air conditioner, and is a current limit obtained from the temperature of an inverter that supplies three-phase power to the permanent magnet type synchronous motor. According to the value, the current setting means for setting the synchronous operation current at the start-up, and the output voltage or output current of the inverter in the rotation stable period after the start-up is monitored, and the synchronous voltage is output using the output voltage or output current. A liquefaction determination value for determining whether or not the refrigerant in the compressor is liquefied is calculated using current update means for updating the operating current and the output voltage or output current of the inverter during the rotation speed stabilization period. Calculating means for determining, and determining means for determining whether or not the liquefaction determination value exceeds a liquefaction reference value, wherein the current update means includes the liquefaction determination value. If the value does not exceed the liquefaction reference value, to provide a control apparatus of the synchronous operation current permanent magnet synchronous motor for updating.

According to such a configuration, since the synchronous operation current at the time of startup is set according to the current limit value obtained from the temperature of the inverter that supplies the three-phase current to the permanent magnet type synchronous motor, Can be prevented from flowing to the inverter. Further, by setting the current as close as possible to the current limit value as the synchronous operation current, the startup success rate of the permanent magnet synchronous motor can be increased.
Further, after the start-up, the output voltage or output current of the inverter during the rotation stabilization period is monitored, so that the motor load can be estimated using these values. And after starting, it becomes possible to aim at reduction of electric power consumption by updating the above-mentioned synchronous operation current to the suitable current value which considered these motor loads, and to realize efficient motor drive. Can do.
Furthermore, according to the above configuration, if the temperature of the inverter can be acquired, it is possible to set the synchronous operation current at start-up, so it is necessary to acquire sensor information from a motor, a compressor, or the like. There is no. Thereby, the apparatus configuration can be simplified.
According to such a configuration, after startup, a liquefaction determination value for determining whether or not the refrigerant in the compressor is liquefied is calculated based on the output voltage or output current of the inverter during the rotation stabilization period. When the liquefaction determination value does not exceed the liquefaction reference value, the synchronous operation current is updated by the current update means. Thereby, when the refrigerant of the compressor is not liquefied, efficient motor operation is realized by the synchronous operation current updated by the current update means, while when the refrigerant of the compressor is liquefied. The operation corresponding to the liquefaction is performed.
The rotation stabilization period is a period during which the number of rotations of the motor is stable, and can be set as appropriate. For example, the rotation speed is 10 rps to 15 rps.

  In the control device for the permanent magnet synchronous motor, the current setting unit may obtain the current limit value according to a temperature characteristic of a switching element included in the inverter.

  According to such a configuration, the current limit value is obtained based on the temperature characteristics of the switching element that is the main component of the inverter. Thereby, it becomes possible to prevent deterioration and damage of the switching element due to overcurrent. Examples of the switching element include a power transistor.

  The above-described permanent magnet type synchronous motor control device is mounted on an electric vehicle such as a fuel cell vehicle (FCEV) or a hybrid electric vehicle (HEV), and is used for an air conditioner driven by a battery as a power source. It is suitable for That is, the permanent magnet type synchronous motor control device according to the present invention has a high startup success rate, so that the motor can be started smoothly. As a result, the power loss associated with the startup failure can be reduced, which is suitable for use in an electric vehicle or the like in which the influence of the power loss during startup is a concern.

Further, the control device for the permanent magnet type synchronous motor described above includes voltage command calculation means for setting a voltage command proportional to the motor frequency in two axes of a rotation rectangular coordinate system, and coordinates the two-axis voltage command into three phases. 2-phase / 3-phase conversion means for conversion, PWM control means for applying the 3-phase voltage command to the motor through power conversion by an inverter, and the motor terminal current without detecting the field direction of the motor Feedback means for feedback, power factor angle determining means for determining a power factor angle from the feedback current, and adjusting the power factor angle to a rotation angle used when converting the motor terminal current obtained in three phases into orthogonal coordinates. It is good also as providing the power factor angle lower limit means to do.
The voltage command calculation means is, for example, the voltage command calculation section 11 shown in FIG. 2, the 2-phase / 3-phase conversion means is, for example, the 2-phase / 3-phase conversion section 12, and the PWM control means is, for example, PWM In the control unit 13, a power factor angle determination unit corresponds to, for example, the power factor angle calculation unit 16, and a power factor angle adjustment unit corresponds to, for example, the three-phase / two-phase conversion unit 14.

The present invention relates to a control method for a permanent magnet type synchronous motor used as a drive source for a compressor of an in-vehicle air conditioner, and a current limit obtained from the temperature of an inverter that supplies three-phase power to the permanent magnet type synchronous motor. Depending on the value, the current setting process for setting the synchronous operation current at the start-up and the output voltage or output current of the inverter during the rotation stabilization period after the start-up are monitored, and the output voltage or output current is used to A liquefaction determination value for determining whether or not the refrigerant in the compressor is liquefied is calculated using a current update process for updating the operating current and the output voltage or output current of the inverter during the rotation speed stabilization period. And a determination process for determining whether or not the liquefaction determination value exceeds a liquefaction reference value, wherein the current update process includes the liquefaction determination value. If the value does not exceed the liquefaction reference value, a control method of the permanent magnet synchronous motor for updating the synchronous operation current.

  In the control method of the permanent magnet type synchronous motor, the current setting process may be to obtain the current limit value according to a temperature characteristic of a switching element included in the inverter.

The present invention is a control program for controlling a permanent magnet type synchronous motor used as a drive source of a compressor of an in-vehicle air conditioner, and is based on the temperature of an inverter that supplies three-phase power to the permanent magnet type synchronous motor. Depending on the required current limit value, the current setting process for setting the synchronous operation current at startup and the output voltage or output current of the inverter during the rotation stabilization period after startup are monitored, and this output voltage or output current is used. Liquefaction for determining whether or not the refrigerant in the compressor is liquefied using the current update process for updating the synchronous operation current and the output voltage or output current of the inverter in the rotation speed stabilization period. Calculation processing for calculating a determination value and determination processing for determining whether the liquefaction determination value exceeds a liquefaction reference value are executed on a computer So, the current update process, when said liquefaction determining value does not exceed the liquefaction reference value, providing the synchronous operation current permanent magnet synchronous motor control program for updating the.

  In the control program for the permanent magnet type synchronous motor, the current setting process may obtain the current limit value according to a temperature characteristic of a switching element included in the inverter.

  ADVANTAGE OF THE INVENTION According to this invention, there exists an effect that a permanent magnet type synchronous motor used for the drive of the compressor of a vehicle-mounted air conditioner can be started smoothly.

Embodiments according to the present invention will be described below with reference to the drawings.
First, a control device and a control method for a permanent magnet type synchronous motor in a normal state will be described with reference to FIGS. 1 to 5, and then a control method at the start-up related to the present invention will be described with reference to FIGS. To do.

FIG. 1 is a diagram illustrating a schematic configuration of a drive control device for an electric compressor to which a control device for a permanent magnet type synchronous motor according to the present embodiment is applied. In FIG. 1, a drive control device 1 for an electric compressor includes an inverter 2 and a control device (a control device for a permanent magnet type synchronous motor) 3.
The inverter 2 includes six power transistors 4a to 4f. These six power transistors 4a to 4f are turned on / off by the control device 3 to convert the DC voltage supplied from the battery 5 mounted on the vehicle into a three-phase pseudo AC voltage in the form of a rectangular pulse train, It supplies to the motor 7 with which the electric compressor 6 is provided. The control device 3 acquires each sensor detection information from the inverter 2, the motor 7, etc., and controls the inverter 2 based on these information. A control method realized by the control device 3 will be described later.
The motor 7 is, for example, a sensorless brushless motor, and includes a stator having a coil wound around a yoke and a rotor having a permanent magnet. The rotor is drivingly connected to the compressor 8 of the electric compressor 6, and the driving force of the motor 7 is transmitted to the compressor 8, so that the refrigerant is compressed.

  The torque τ of such a permanent magnet type synchronous motor is generally expressed by the following equation (1).

  Here, Λd is an induced voltage coefficient, and id and iq are armature currents of d-axis and q-axis, respectively. Ld and Lq are the d-axis and q-axis inductances, respectively, and n is the number of pole pairs. The d axis is an axis provided in the field direction of the motor rotor, and the q axis is an axis whose phase is advanced 90 degrees from the d axis.

  The first term of equation (1) represents the torque (magnet torque) generated by the q-axis current flowing in a direction perpendicular to the field direction by the magnet. Further, the second term of the same expression represents the torque (reluctance torque) generated when the reluctance is different between the d-axis direction and the q-axis direction. In the surface magnet type motor (SPM) where Ld = Lq, the second term can be ignored. Even in the case of an internal magnet type motor (IPM), if the difference between Ld and Lq is small, the second term is often ignored.

  Returning to FIG. 1, reference numeral 9 is a temperature sensor that detects the temperature of the inverter 2. Further, a current sensor (not shown) for detecting a current supplied from the inverter 2 to the motor 7 is provided. These sensor detection values are transferred to the control device 3 at a predetermined timing.

FIG. 2 is a functional block diagram of the control device 3. As shown in FIG. 2, the control device 3 includes a voltage command calculation unit 11, a 2 phase / 3 phase conversion unit 12, a PWM control device 13, a 3 phase / 2 phase conversion unit 14, a power factor angle calculation unit 15, a proportional device. 16 and an integrator 17.
In FIG. 2, ωm is the rotational speed command, n is the number of pole pairs of the motor, ω1 is the inverter output frequency (primary frequency), vδ * and vγ * are the δ-axis and γ-axis voltage commands, vu *, vv * and vw, respectively. * Is the voltage command for u-phase, v-phase, and w-phase, vu, vv, and vw are output voltages for u-phase, v-phase, and w-phase, respectively, iu, iv, and iw are u-phase, v-phase, and w-phase, respectively , Iδ, iγ are inverter output currents of the δ-axis and γ-axis, iδ is an exciting current component, and iγ is a torque current component. θ is the output voltage phase, and φ is the power factor angle.

The control device 3 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory) and the like (not shown). A series of processing procedures for realizing the functions of the respective units described above are recorded in a computer-readable recording medium in the form of a program, and the CPU reads the program into a RAM or the like to perform information processing / arithmetic processing. By executing the function, the functions of the respective units including the voltage command calculation unit 11 are realized.
Examples of the computer-readable recording medium include a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, and a semiconductor memory.

  In FIG. 2, the voltage command calculation unit 11 performs a three-phase / two-phase conversion on the detected three-phase currents iu, iv, and iw of u, v, and w, an inverter output frequency ω1, The δ-axis voltage command vδ * and the γ-axis voltage command vγ * are obtained by the following formulas (2-1) and (2-2) using the proportionality constant K, the d-axis induced voltage coefficient Λd, and the proportional gain K. .

  Below, the control when the voltage command calculation part 11 is made into said Formula (2-1) and (2-2) is demonstrated. First, in order to help understanding, a case where the power factor angle φ (i) is 0 will be described. Since φ is a power factor angle, when the phase difference between the voltage applied to the motor 7 and its current is 0, the power factor represented by cos φ is 1. Therefore, this control is so-called power factor 1 control.

In the voltage command calculation by the above formulas (2-1) and (2-2), for example, if the γ-axis voltage command vγ * is smaller than the motor terminal voltage, the δ-axis inverter output current iδ is negative in order to weaken the field. become. On the other hand, if vγ * is large, the field becomes stronger and iδ is positive.
Specifically, in the calculation of the equation (2-1), the δ-axis voltage command performs negative proportional control so that the δ-axis current iδ becomes zero. Thus, if there is a positive or negative fluctuation of i δ, the voltage command v δ * is determined so as to quickly eliminate the fluctuation of i δ by the gain Kδ.

  The γ-axis voltage command vγ * is set to a voltage value that compensates for the voltage of Λdω1 corresponding to the induced voltage, and in addition, in order to perform an operation for setting the δ-axis current iδ to 0, here, integral control for integrating iδ is performed. I do. That is, in the calculation of Expression (2-2), if the δ-axis current iδ accumulates with either positive or negative value, a voltage value that returns to the original value with a larger value is determined. Although integral control is used here, proportional control, proportional integral control, or the like may be used depending on control responsiveness.

  By doing so, iδ becomes 0, and when iδ becomes 0, vδ also becomes 0. Eventually, the current passed through the motor 7 and the motor applied voltage are only γ-axis components, and the phase coincides, so that the power factor is 1. This alone minimizes the product of voltage and current and enables power-saving control.

  However, in the permanent magnet type synchronous motor, since the reluctance torque which is the second term of the formula (1) can be used, the current can be further reduced by using both the magnet torque and the reluctance torque in a balanced manner. When the motor current (absolute value obtained by combining the δ axis and the γ axis) I flows with an advance angle θ with respect to the induced voltage, the d-axis current id and the q-axis current iq are expressed by the equations (3-1) and (3-2). ).

  The condition for maximizing the motor torque τ with respect to the motor current I is θ of τ (formula (4-1)) obtained by substituting formulas (3-1) and (3-2) into formula (1). The derivative with respect to is zero. If this is made into Formula (4-2), it will become as follows.

  When I · sin θ and I · cos θ in the above equation (4-2) are expressed by id and iq in the equations (3-1) and (3-2), the following equation (5) is obtained.

Equation (5) is an equation representing the relationship of (id + A) ² -iq ² = A ^{2 where} A = Λd / 2 (Ld−Lq), where id is the vertical axis and iq is the horizontal axis. It becomes a graph as shown in.

  Therefore, the figure shows the combination of id and iq when the minimum current is reached. However, since the relationship between id and iq includes a square root, a table for use in control is used. This method is required.

  Therefore, the inventor diligently investigated whether it was possible to control with the phase difference between the motor current I and the motor applied voltage V from a different viewpoint. First, since φ is the difference between the phase of the motor applied voltage V and the phase of the motor current I, it is expressed by the following equation (6).

As described above, the relationship between id and iq at the minimum current is (id + A) ² −iq ² = A ² , which is a hyperbola, and therefore, according to the hyperbolic function (sinh, cosh), the following equation (7-1) ) And (7-2).

When α is sufficiently small and can be regarded as 0, it can be approximated as id = Aα ² and iq = Aα, respectively. Further, vd and vq obtained by capturing the voltage applied to the motor on the d-axis and the q-axis can be regarded as the following expressions (8-1) and (8-1) from an equivalent expression of the motor circuit. This is because the resistance is negligible at the normal operation speed.

  Using these equations, the phase difference φ in equation (6) can be approximated as in the following equation (9).

Here, since the current I can be expressed by the following equation (10), the phase difference φ is eventually expressed by the following equation (11). That is, it has been found that the phase difference φ is substantially proportional to the current. Further, iδ = 0 by the control, and I is proportional to iγ, so that the phase difference φ is also proportional to iγ.
FIG. 4 shows the relationship between the phase difference φ and the current I obtained by plotting using the d-axis current and the q-axis current without approximation as described above. Even in such a case, it is almost proportional, and the validity of control using the proportional relationship can be understood.

  As described above, the control of the minimum current necessary for generating the torque can be realized by positively controlling the power factor angle (phase difference) instead of φ = 0. Therefore, in the present embodiment, as shown in FIG. 2, the power factor angle adjusting means is set so that the rotation axis used when the current of the motor terminal is converted into three-phase / two-phase is θ-φ instead of θ. did. Since φ is a function of the current I, as shown in the figure, first, I is obtained using the fed back γ-axis current (iδ is controlled to 0). When I is obtained, φ is obtained by multiplying it by a constant. Thus, φ is subtracted from the rotation axis θ of the three-phase / two-phase conversion.

  Then, the current subjected to the three-phase / two-phase conversion with θ-φ as the rotation axis is negatively fed back to the speed command nω *, which is a frequency multiplied by the gain Kω9, so that the synchronous motor operates stably. Is fixed. This is because the load increases and the current increases when the rotor position is delayed relative to the rotating magnetic field. Conversely, the load decreases and the current decreases as the rotor position advances relative to the rotating magnetic field. It stabilizes by correcting. (2-1) and (2-2) are controlled so that vδ = Iδ = 0, so that the phase used for current three-phase / 2-phase conversion and voltage two-phase / 3-phase conversion is used. Are different, the difference φ is controlled to be the power factor angle.

Since the relationship between the current I and the phase difference φ is a proportional relationship, an appropriate proportionality constant may be selected to derive φ through calculation, or accuracy in a large current value range may be obtained. For example, the relationship between I and φ may be tabulated. Even in the case of adopting a table configuration, there is an advantage that it is not necessary to take fine table data because it is almost proportional.
Even in this case, unlike referring to a two-dimensional table that is a combination of i δ and i γ, I can be obtained by actual feedback, so φ can be uniquely determined, and an appropriate phase difference φ can always be obtained. Can be sought.

  As described above, in the normal state, the torque of the permanent magnet type synchronous motor is controlled with the minimum current in consideration of the reluctance torque of the permanent magnet type synchronous motor. In addition, since the torque control by the minimum current is possible only by changing the rotation shaft angle at the time of the three-phase / two-phase conversion without requiring a complicated calculation, the configuration becomes simple and the maintainability is improved. Furthermore, in this embodiment, as shown in FIG. 5, the torque range in which V / f control is appropriate is expanded compared to the case of power factor 1 control, and simple V / f control from low speed rotation to high speed rotation is performed. It is possible to operate with the current minimized while maintaining the basic tone.

  Moreover, it becomes possible to contribute to size reduction of an industrial product and power saving by performing the above control. For example, a motor for a compressor of an air conditioner is strongly demanded to save power because the air conditioner is a device that consumes a large amount of power together with a request for downsizing. Permanent magnet type synchronous motors have been adopted as one of the manifestations. However, if minimum current control can be achieved with a compact configuration according to the present invention, the above requirements will be met.

Next, a control method at the time of starting the motor, which is performed by the above-described permanent magnet type synchronous motor control device, which is a feature of the present invention, will be described.
As described above, the control device according to the present embodiment determines the output voltage and frequency according to the motor rotation speed command, not the motor load, during normal operation, and drives the motor so as to obtain optimum characteristics at the time of rating. is doing. However, with such a control method, the stability is lost and it becomes difficult to drive at a low speed where the load cannot be ignored, for example, at the time of startup. Therefore, at the time of start-up, instead of the above-described V / F control, a constant synchronous operation current is supplied to the motor regardless of the position of the rotor of the motor and the magnitude of the motor load. The synchronous operation current is set appropriately.

  Hereinafter, the control procedure of the control device 3 at the time of activation will be described with reference to FIGS. 6 and 7. The processes shown in FIGS. 6 and 7 are realized by the voltage command calculation unit 11 shown in FIG. 2, for example. That is, in the present embodiment, the voltage command calculation unit 11 has a function realized by the current setting unit, the current update unit, the calculation unit, and the determination unit of the present invention. Specifically, the CPU built in the control device 3 executes the following control program corresponding to the function realized by the voltage command calculation unit 11, whereby each function of the voltage command calculation unit 11, the synchronous current setting And processing such as updating.

First, when a start command is given from a host computer, the voltage command calculation unit 11 obtains a current limit value based on the temperature of the inverter 2 (step SA1 in FIG. 6). This current limit value is a value determined according to the characteristics and temperature of the power transistors 4a to 4f included in the inverter 2. For example, as shown in FIG. 8, the voltage command calculation unit 11 has a table that associates the inverter temperature with the current limit value in advance, and by referring to this table, the current limit corresponding to the temperature at the time of startup is stored. Find the value. Here, the current limit value is set lower as the temperature becomes higher. Further, instead of the above table, the current limit value may be obtained by calculation using a function formula with temperature as a variable.
The sensor value transferred from the temperature sensor 9 can be used as the temperature of the inverter 2.

  Subsequently, the voltage command calculation unit 11 calculates an overcurrent determination value Th by further subtracting a predetermined value (for example, any value from 3A to 7A, preferably 5A) from the obtained current limit value. Furthermore, it is determined whether or not the overcurrent determination value Th exceeds a preset synchronous operation limit current TBDmax (step SA2).

  As a result, if the overcurrent determination value Th exceeds the synchronous operation limit current TDBmax, the synchronous operation limit current TDBmax is set as the synchronous operation current TDB at the time of startup (step SA3), while the overcurrent determination value Th Is equal to or less than the synchronous operation limit current TDBmax, an overcurrent determination value Th is set as the synchronous operation current TDB (step SA4). Note that the process from step SA1 to step SA4 corresponds to the current setting process of the present invention.

  Subsequently, the voltage command calculation unit 11 obtains a δ-axis voltage command vδ * and a γ-axis voltage command vγ * based on the set synchronous operation current TDB, respectively, and obtains a 2-phase / 3-phase conversion unit 12 (see FIG. 2). Output to. Thereby, the control of the inverter 2 based on these voltage commands is performed by PWM, and the synchronous operation current TDB is supplied to the motor 7 via the inverter 2. The motor 7 starts rotating by the supply of the synchronous operation current TDB, gradually increases the rotational speed, and stabilizes at the rotational speed corresponding to the synchronous operating current TDB.

  On the other hand, the current command calculation unit 11 monitors the γ-axis terminal voltage Vγ during the rotation stabilization period (for example, the period when the rotation speed is 10 to 15 rps) in which the rotation speed of the motor 7 is stable, and the rotation speed reaches 15 rps. At the time, the average value Vγave of the γ-axis terminal voltage Vγ during this rotation stabilization period is calculated (step SA6). Based on this average value Vγave, the synchronous operation current is updated (step SA7). Specifically, when the average value Vγave of the γ-axis terminal voltage Vγ is equal to or less than the reference value Vref (for example, 28.6 V) for starting load determination, the synchronous operation current is lower than the previously set synchronous operation current. Set to a value, for example 35A. On the other hand, when the average value Vγave exceeds the reference value Vref for starting load determination, it is updated to the current limit value. Note that the processing from step SA5 to step SA7 corresponds to the current update process of the present invention. The reference value Vref for starting load determination is a value that can be arbitrarily set based on experience. In the present embodiment, the reference value Vref is set to a value that minimizes start-up failure based on the average value Vγave.

  In this way, when the synchronous operation current is updated, it is subsequently determined whether or not a starting failure has occurred (step SA8). In this process, for example, it is determined whether or not an overcurrent is flowing through the inverter circuit and whether or not a command such as an emergency stop for notifying the abnormality of the vehicle on which the air conditioner is mounted is generated. .

  As a result, when it is determined in step SA8 that no startup failure has occurred, it is subsequently determined whether or not the compressor is operating normally (step SA9). Specifically, the maximum value Imax (hereinafter referred to as “current maximum value”) of the absolute value of the inverter output current when a predetermined time elapses after the inverter output reaches a value corresponding to the required rotational speed is based on the abnormality determination value Iref. It is determined whether or not it is larger. Here, the abnormality determination value Iref depends on the type and size of the motor 7, the type and size of the compressor 8, but the current value that is the minimum torque of the motor 7 within the operating conditions of the compressor 8, for example, The current value is set to about 3A.

  As a result, when the maximum current value Imax is equal to or less than the abnormality determination value Iref, it is determined that the operation of the compressor 8 is normally performed, and the operation is gradually shifted to the steady operation (step SA10). That is, the operating state of the motor 7 smoothly shifts to the above-described V / F control while gradually adjusting the control amount from control at startup to control at steady state.

  On the other hand, if the maximum current value Imax is equal to or less than the abnormality determination value Iref in step SA9, it is determined that an abnormality has occurred in the operation of the compressor 8, and output to the inverter 2 is stopped (step SA11). Then, after a predetermined time has elapsed (step SA12), the process proceeds to step SA17 shown in FIG.

Next, if it is determined in step SA8 that a startup failure has occurred, inverter failure determination is performed (step SA13). As a result, when an abnormality has occurred in the inverter 2, the drive of the inverter 2 is stopped, the drive of the motor 7 is stopped, and further, the occurrence of the abnormality is notified to the host computer, so that the user is notified. On the other hand, an abnormality is reported (step SA14). On the other hand, if it is determined that no failure has occurred in the inverter 2, after the predetermined time has elapsed (step SA15), the above-described processing from step SA1 to step SA15 is performed a predetermined number of times (for example, three times). It is determined whether or not it has been repeated (step SA16). As a result, if the predetermined number of times has not been repeated, the process returns to step SA1 and the processing from step SA1 is performed again according to the procedure described above.
On the other hand, if it is determined in step SA16 that the process has been repeated a predetermined number of times, the process proceeds to step SA17 in FIG.

  In step SA17 in FIG. 7, the synchronous operation current is reset. In the process of resetting the synchronous operation current, the same process as the process from steps SA1 to SA4 described above is performed. That is, when the overcurrent determination value Th exceeds the synchronous operation limit current TDBmax, the synchronous operation limit current TDBmax is set as the synchronous operation current TDB, while the overcurrent determination value Th is equal to or less than the synchronous operation limit current TDBmax. If there is, an overcurrent determination value Th is set as the synchronous operation current TDB. In this way, when the synchronous operation current is reset, the motor idling operation is subsequently performed. The idling operation is for discharging the liquid refrigerant in the compressor 8 and is rotated for a predetermined time (for example, about several seconds to several tens of seconds) at a constant low rotation speed.

When the idling operation is completed, the motor is then rotated at a moderate angular acceleration (step SA19). For example, the motor is rotated at an angular acceleration of 720 rpm / s. As a result, the same low speed start-up as the normal start control is achieved. Subsequently, similarly to the above step SA8, it is determined whether or not a start-up failure has occurred (step SA20). As a result, if no abnormality has occurred, an inverter failure is subsequently determined (step SA21). ). As a result, if an inverter failure has occurred, the operation is stopped (step SA22). On the other hand, if an inverter failure has not occurred, it is determined whether the processing of steps SA17 to SA21 has been repeated a certain number of times (step S22). SA23).
In step SA23, if the processes in steps SA17 to SA21 are not repeated a predetermined number of times or more, after waiting for a predetermined time (step SA24), the process returns to step SA17 to reset the synchronous operation current. On the other hand, if it is determined in step SA23 that the process has been repeated a predetermined number of times, the process returns to step SA1 shown in FIG.

  On the other hand, if it is determined in step SA20 in FIG. 7 that no startup failure has occurred, it is determined whether or not the compressor operation is normal (step SA25). If not normal (step SA26), the inverter output is stopped (step SA27), and then the process proceeds to step SA23 described above.

  As described above, according to the control device for a permanent magnet type synchronous motor according to the present embodiment, according to the current limit value obtained from the temperature of the inverter 2 that supplies a three-phase current to the permanent magnet type synchronous motor. Since the synchronous operation current at the time of starting is set, it is possible to prevent an overcurrent from flowing to the inverter at the time of starting. Further, by setting the current as close as possible to the current limit value as the synchronous operation current, the startup success rate of the permanent magnet synchronous motor can be increased. In this case, the current limit value is obtained based on the temperature characteristics of the power transistors 4a to 4f which are the main components of the inverter 2. As a result, it is possible to prevent the power transistors 4a to 4f from being deteriorated and damaged due to overcurrent.

Furthermore, since the output voltage or output current of the inverter is monitored during the rotation stabilization period after startup, the motor load can be estimated using these values. Then, by updating the synchronous operation current to a suitable current value in consideration of these motor loads, it is possible to reduce power consumption and realize efficient motor driving.
Furthermore, according to the above configuration, if the temperature of the inverter can be acquired, it is possible to set the synchronous operation current at start-up, so it is necessary to acquire sensor information from a motor, a compressor, or the like. There is no. Thereby, the apparatus configuration can be simplified.

In the above embodiment, the synchronous operation current is constantly updated in step SA7. For example, in step SA3, the overcurrent determination value Th is equal to or less than the synchronous operation limit current TDBmax, and in step SA4, the synchronous operation current is updated. If the overcurrent determination value Th is set, the synchronous operation current set in step SA4 may be maintained without updating the synchronous operation current in step SA7.
In addition, the update of the synchronous operation current is performed based on the voltage value of one of the three-phase output voltages of the inverter 2 instead of the method of updating the synchronous operation current based on the γ-axis terminal voltage Vγ described above. The current may be determined, or the synchronous operation current may be determined based on the output current of the inverter 2 instead of the voltage.

[Second Embodiment]
Next, a control device for a permanent magnet type synchronous motor according to a second embodiment of the present invention will be described with reference to the drawings.
The device configuration of the control device according to the second embodiment is basically the same as the device configuration of the control device 3 according to the first embodiment, but the control content performed in the voltage command calculation unit 11 is different. Specifically, a liquid compression determination (see step SB7 in FIG. 9) for determining whether or not the refrigerant in the compressor 8 is liquefied after the motor is started is further provided.
Hereinafter, the control performed in the voltage command calculating part 11 which concerns on this embodiment is demonstrated with reference to FIG. FIG. 9 is a flowchart showing a control procedure at the time of starting the permanent magnet type synchronous motor according to the second embodiment of the present invention. In FIG. 9, the same processing steps as those in FIGS. 6 and 7 are denoted by the same steps, and the description thereof is omitted.

First, by performing steps SA1 to SA4, the synchronous operation current TDB is set, and the operation of the motor 7 based on the synchronous operation current TDB is started. Thereafter, in step SA5, the γ-axis terminal voltage Vγ of the inverter 2 in the rotation stable period is monitored, and in step SA6, an average value Vγave of the γ-axis terminal voltage Vγ in the rotation stable period is calculated. Subsequently, in step SB7, a liquid compression determination which is a feature of the present embodiment is performed.
This liquid compression determination is to determine whether or not torque is unexpectedly required for compression as the refrigerant in the compressor 8 is liquefied. Specifically, the average value Vγave of the γ-axis terminal voltage Vγ calculated in step SA6 is determined as a liquefaction determination value L (= Vγave) for determining whether or not liquefaction has occurred, and this liquefaction determination value L Whether or not liquefaction exceeds the preset liquefaction reference value Lref is determined. Here, the liquefaction reference value Lref is a value that is empirically set. For example, the relationship between the liquefaction determination value L and the liquefaction of the refrigerant is obtained by experiments and the critical value for liquefaction is set as the liquefaction reference value Lref. It is possible to accurately determine whether or not the refrigerant is liquefied.

In step SB7 described above, when the liquefaction determination value L exceeds the liquefaction reference value Lref, it is determined that liquefaction has not occurred, that is, the refrigerant in the compressor 8 has not been liquefied. The process proceeds to step SA13, and thereafter, the process proceeds according to the process procedure according to the first embodiment.
On the other hand, when the liquefaction determination value L is equal to or less than the liquefaction reference value Lref in step SB7, it is determined that liquefaction has occurred, that is, the refrigerant in the compressor 8 has been liquefied, and the process proceeds to step SB8. Then, it waits for a predetermined period. Thus, by waiting for a predetermined period, it waits for the refrigerant in the compressor to stabilize.

  Next, the process proceeds to step SA17 shown in FIG. 7, where the synchronous operation current is reset based on the current temperature of the inverter 2, and then the motor idling operation is performed to discharge the liquid refrigerant ( Step SA18 in FIG. When the idling operation is completed, the motor is operated with a moderate angular acceleration (step SA19), and thereafter, the process proceeds according to the processing procedure according to the first embodiment.

  As described above, according to the control apparatus for a permanent magnet type synchronous motor according to the present embodiment, it is determined whether or not the refrigerant in the compressor is liquefied from the output voltage of the inverter in the rotation stable period after startup. The liquefaction determination value L is calculated, and the presence or absence of liquid compression is determined based on whether or not the liquefaction determination value L exceeds the liquefaction reference value Lref. When it is determined that liquefaction has occurred, suitable operation control for coping with liquefaction is performed. Therefore, even when liquefaction has occurred, the motor can be started smoothly.

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the specific structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.
For example, the control device for a permanent magnet type synchronous motor according to the present invention controls the torque of the permanent magnet type synchronous motor with a minimum current in consideration of the reluctance torque of the permanent magnet type synchronous motor during normal operation. Instead of such a control method, it is also possible to employ a configuration in which control of a known permanent magnet type synchronous motor that is normally performed, for example, control in which power factor = 1 is performed.
In the above-described embodiment, it is assumed that the control device is configured by a computer system, but it is not necessary to be limited to such a configuration. For example, each unit can be configured by separate hardware.

It is a block diagram which shows the system configuration | structure which concerns on one Embodiment of this invention. It is a figure which shows the functional block of the control apparatus shown in FIG. It is a graph which shows completion of d-axis current and q-axis current when it becomes the minimum current, the vertical axis is d-axis current, and the horizontal axis is q-axis current. It is a graph which shows the relationship between the electric current when it becomes the minimum electric current, and a phase difference, a vertical axis | shaft is phase difference and a horizontal axis is an electric current. It is a graph which shows the relationship between the electric current and torque in the case of power factor 1 control and the case of this invention, a vertical axis | shaft is a phase difference and a horizontal axis is a torque. It is a flowchart which shows the control procedure at the time of starting performed with the control apparatus which concerns on the 1st Embodiment of this invention. It is a flowchart which shows the control procedure at the time of starting performed with the control apparatus which concerns on the 1st Embodiment of this invention. It is a graph which shows the relationship between the temperature of a power transistor, and a current limiting value, a vertical axis | shaft is a current limiting value and a horizontal axis is temperature. It is a flowchart which shows the control procedure at the time of starting performed with the control apparatus which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric compressor drive control device 2 Inverter 3 Control devices 4a to 4f Power transistor 5 Battery 6 Electric compressor 7 Motor 8 Compressor 9 Temperature sensor 11 Voltage command calculation unit 12 Two-phase / three-phase conversion unit 13 PWM control device 14 3-phase / 2-phase conversion unit 15 Power factor angle calculation unit 16 Proportional device 17 Integrator

Claims (6)

A control device for a permanent magnet type synchronous motor used as a drive source of a compressor of an in-vehicle air conditioner,
Current setting means for setting a synchronous operation current at startup according to a current limit value obtained from the temperature of an inverter that supplies three-phase power to the permanent magnet type synchronous motor;
Current update means for monitoring the output voltage or output current of the inverter in the rotation stabilization period after startup, and using the output voltage or output current to update the synchronous operation current ;
A calculation means for calculating a liquefaction determination value for determining whether or not the refrigerant in the compressor is liquefied using the output voltage or output current of the inverter in the rotation speed stable period;
Determination means for determining whether the liquefaction determination value exceeds a liquefaction reference value,
It said current update means, the liquefied when the determination value does not exceed the liquefaction reference value, the permanent magnet for updating the synchronous operation current synchronous motor control device.   The control device for a permanent magnet type synchronous motor according to claim 1, wherein the current setting means obtains the current limit value according to a temperature characteristic of a switching element included in the inverter. A control method of a permanent magnet type synchronous motor used as a drive source of a compressor of an in-vehicle air conditioner,
A current setting process for setting a synchronous operation current at start-up according to a current limit value obtained from the temperature of an inverter that supplies three-phase power to the permanent magnet synchronous motor;
Monitors the output voltage or output current of the inverter in the rotation stabilizing period after startup, using the output voltage or output current, a current update process of updating the synchronous operation current,
A calculation process for calculating a liquefaction determination value for determining whether or not the refrigerant in the compressor is liquefied using the output voltage or output current of the inverter in the rotation speed stabilization period;
A determination process for determining whether or not the liquefaction determination value exceeds a liquefaction reference value,
The current update process, when the liquefaction determining value does not exceed the liquefaction reference value, the control method of the synchronous operation current permanent magnet synchronous motor to update the.   The method for controlling a permanent magnet type synchronous motor according to claim 3, wherein in the current setting process, the current limit value is obtained according to a temperature characteristic of a switching element included in the inverter. A control program for controlling a permanent magnet type synchronous motor used as a drive source of a compressor of an in-vehicle air conditioner,
A current setting process for setting a synchronous operation current at startup according to a current limit value obtained from the temperature of an inverter that supplies three-phase power to the permanent magnet synchronous motor;
A current update process for monitoring the output voltage or output current of the inverter in the rotation stabilization period after startup, and using the output voltage or output current to update the synchronous operation current ;
A calculation process for calculating a liquefaction determination value for determining whether or not the refrigerant in the compressor is liquefied using the output voltage or output current of the inverter in the rotation speed stabilization period;
A determination process for determining whether or not the liquefaction determination value exceeds a liquefaction reference value;
The current update process is a control program for a permanent magnet type synchronous motor that updates the synchronous operation current when the liquefaction determination value does not exceed the liquefaction reference value .   The control program for a permanent magnet type synchronous motor according to claim 5, wherein the current setting process obtains the current limit value according to a temperature characteristic of a switching element included in the inverter.

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