JP2008109798A - Control device for multiphase rotary machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve response of q-axis current during an increase of required torque to a multiphase rotary machine. <P>SOLUTION: A command current iqc is calculated based on the required torque Td, and a command voltage vqc is calculated based on a gap between the command current and an actual current iq. A command voltage vdc in d-axis is calculated based on a gap between the command current idc and the actual current id. The command current idc in the d-axis is the sum of feedback current idb and open loop current idf. The feedback current idb is calculated based on a gap between the length of the command voltage vectors (vdc, vqc) and permissible voltage Vom. The open loop current idf is calculated by open loop control so that the length of the command voltage vectors may become within the permissible voltage Vom when the command current iqc flows. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a control device for a multiphase rotating machine that controls the output of the multiphase rotating machine by operating a switching element of an inverter.

  For example, in a control device for a three-phase motor, the upper limit value of the output voltage of the inverter is limited by the input voltage of the inverter. For this reason, when the induced voltage of the motor increases as the rotational speed of the motor increases, the voltage required to generate a desired output increases, making it difficult to perform output control appropriately. For this reason, under such circumstances, it is well known to perform so-called field weakening control that suppresses the induced voltage by increasing the d-axis current. Thereby, the rotation speed area | region which can control the output of an electric motor can be expanded.

Specifically, for example, the correction amount of the d-axis command current is calculated by feedback control based on a difference between the output voltage value of the inverter calculated from the command voltage on the dq axis for the electric motor and a predetermined value. Has also been proposed (Patent Document 1).
Japanese Patent No. 3566163

  However, depending on the feedback control based on the difference between the output voltage value and a predetermined value, for example, when the required torque increases, the output voltage value exceeds the input voltage of the inverter due to a request to increase the q-axis current. Therefore, it is difficult to increase the d-axis current so as to suppress this quickly. For this reason, it may be difficult to quickly cope with the demand for increasing the q-axis current.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a control device for a multi-phase rotating machine that can appropriately cope with a demand for an increase in q-axis current when the required torque is increased. It is to provide.

  Hereinafter, means for solving the above-described problems and the operation and effects thereof will be described.

  According to a first aspect of the present invention, there is provided a command voltage calculating means for calculating a command voltage for the d-axis and the q-axis for flowing a command current for the d-axis and the q-axis to the inverter, and when the command current for the q-axis is increased And an operation amount calculation means for calculating an operation amount for keeping an output voltage value of the inverter within an allowable range within an allowable range determined according to the command voltage by open loop control.

  When the q-axis command current increases, the output voltage value in the calculation may increase beyond the allowable range. Here, in the above configuration, the operation amount for controlling the output voltage value within the allowable range is calculated by the open loop control. For this reason, compared with the case where the operation amount is calculated to feedback control the output voltage value within the allowable range, the operation amount can be calculated quickly, or the amount of change in the operation amount immediately after the q-axis command current increases. Can be increased. That is, in the feedback control, in order to increase the amount of change in the operation amount immediately after the increase of the q-axis command current, it is necessary to increase the gain. In this case, hunting is likely to occur. For this reason, depending on the feedback control, it is difficult to increase the amount of change in the operation amount immediately after the increase of the q-axis command current.

  According to a second aspect of the present invention, in the first aspect of the present invention, the operation amount to be within the allowable range is a d-axis command current.

  The q-axis command voltage required for flowing the q-axis current decreases as the d-axis current increases. In this regard, in the above configuration, by using the d-axis command current, the q-axis command voltage for flowing a desired q-axis current can be suitably reduced, and the output voltage value is within an allowable range. Can fit.

  According to a third aspect of the present invention, in the second aspect of the invention, the operation amount calculation means calculates an upper limit value of the q-axis command voltage based on the upper limit value of the allowable range and the d-axis command voltage. And a d-axis command current is calculated based on the difference between the command voltage on the q-axis and the upper limit value.

  From the upper limit value of the allowable range and the q-axis command voltage, calculating the upper limit value of the q-axis command voltage that allows the operation output voltage value determined according to the dq-axis command voltage to be within the allowable range Can do. When the actual q-axis command voltage is larger than the upper limit value, it means that the output voltage value in the calculation is a large value exceeding the allowable range. At this time, the difference between the q-axis command voltage and the upper limit value has a correlation with the d-axis current necessary for setting the output voltage value within the allowable range. In this regard, in the above configuration, the d-axis current is calculated based on the difference between the q-axis command voltage and the upper limit value under such circumstances.

  The invention according to claim 4 is the invention according to claim 2, wherein the operation amount calculation means calculates the command current of the d-axis based on a difference between the command current and the actual current in the q-axis. To do.

  When the command current on the q-axis increases, the difference between the command current on the q-axis and the actual current increases, and consequently the command voltage on the q-axis increases. As a result, it is considered that a situation occurs in which the calculated output voltage value determined in accordance with the command voltage exceeds the allowable range. In this regard, in the above configuration, the d-axis command current can be calculated by a simple method by calculating the d-axis command current based on the difference between the q-axis command current and the actual current. In addition, in a device provided with means for calculating the q-axis command voltage based on the difference between the command current and the actual current in the q-axis, based on the difference between the command current and the actual current in the q-axis, This method is particularly effective because the increase amount of the command voltage can be grasped with high accuracy.

  The invention according to claim 5 is the invention according to claim 3 or 4, wherein the manipulated variable calculation means uses the rotational speed of the multiphase rotating machine when calculating the d-axis command current. .

  The amount of decrease in the q-axis voltage when the d-axis current is increased depends on the rotation speed. In this regard, in the above configuration, the required d-axis command current can be calculated more appropriately by using the rotational speed when calculating the d-axis command current.

  According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, when the output voltage value in operation is larger than a threshold voltage, the command voltage is not reduced without decreasing the d-axis command voltage. It further comprises a limiting means for limiting the output voltage value within a threshold voltage by correcting.

  When the operation output voltage value is larger than the threshold voltage, operating the inverter with this command voltage may cause inconveniences such as overmodulation control and reduced controllability. For this reason, there is known a method of correcting the command voltage so that the calculated output voltage value is equal to or lower than the threshold voltage when the threshold voltage is exceeded. However, this may cause the d-axis command voltage to decrease, and thus the d-axis current increase rate may decrease. In this regard, in the above configuration, such a problem can be avoided because the d-axis command voltage is not reduced when the command voltage is corrected.

  The invention according to claim 7 is the invention according to claim 6, wherein the limiting means corrects only the q-axis command voltage when the output voltage value in the calculation is larger than a threshold voltage. .

  In the above configuration, by correcting (reducing and correcting) only the q-axis command voltage, the output voltage value can be made equal to or less than the threshold voltage while the d-axis command voltage remains unchanged. For this reason, an output voltage value can be made below a threshold voltage, without preventing the increase of the d-axis current.

  The invention according to claim 8 is the invention according to claim 6, wherein, when the output voltage value in the calculation is larger than a threshold voltage, the restricting means sets the command voltage while keeping the output voltage value within the threshold voltage. The command voltage is corrected so as to change the phase of the vector to the negative side of the d-axis.

  In the above configuration, by changing the phase of the vector of the command voltage to the negative side of the d-axis while keeping the output voltage value within the threshold voltage, the output voltage value is within the threshold voltage while promoting the increase of the d-axis current. be able to.

  According to a ninth aspect of the present invention, in the eighth aspect of the invention, the phase change is performed by changing the upper limit value of the q-axis command voltage determined based on the d-axis command voltage and the threshold voltage, and the current q-axis command voltage. It is performed according to the difference between and.

  From the difference between the d-axis command voltage and the threshold voltage, the upper limit value of the q-axis command voltage for setting the output voltage value within the threshold voltage can be calculated. For this reason, the upper limit value of the q-axis command voltage can be grasped based on these two values. The excess of the current q-axis command voltage with respect to the upper limit value of the q-axis command voltage determines the amount of increase required for the d-axis command current. In this regard, in the above configuration, the d-axis current can be appropriately increased by changing the phase according to the difference between the upper limit value of the q-axis command voltage and the current q-axis command voltage.

  According to a tenth aspect of the present invention, in the invention according to any one of the sixth to ninth aspects, the command voltage calculating means is configured to determine d based on a cumulative value of a difference between the command current and the actual current in the d-axis and the q-axis. Each of the command voltages for the axes and q-axis is calculated, and when the output voltage value in calculation is larger than a threshold voltage, the increase of the cumulative value is prohibited only for the q-axis.

  When the cumulative value is calculated at the time of restriction by the restriction means, it becomes an appropriate value when the q-axis command voltage is actually applied to the q-axis of the multiphase rotating machine, regardless of the restriction by the restriction means. Thus, the cumulative value will increase. For this reason, the accumulated value becomes excessive, and it becomes difficult to set the command voltage appropriately. In this regard, in the above configuration, such a problem can be avoided by prohibiting an increase in the cumulative value on the q axis when the restriction is performed.

  In particular, in the above configuration, since the d-axis is not limited by the limiting means, the accumulated value used for calculating the d-axis command voltage is desirably updated according to the difference between the command current and the actual current. In this respect, in the above configuration, since the increase in the accumulated value of the d-axis is not prohibited, the accumulated value of the d-axis can be set to an appropriate value, and the d-axis controllability can be kept good. can do.

  According to an eleventh aspect of the present invention, in the invention according to any one of the fifth to tenth aspects, an upper limit value of the allowable range is set to be equal to or lower than the threshold voltage.

  In the above configuration, by setting the upper limit value of the allowable range to be equal to or lower than the threshold voltage, the open loop control for keeping the output voltage value within the allowable range can be quickly started. As a result, when the q-axis command current increases The d-axis current can be increased rapidly.

  The invention according to claim 12 is the invention according to any one of claims 1 to 11, wherein the upper limit value of the allowable range and the arithmetic value are set so that the output voltage value in the calculation is within the allowable range. Feedback means for operating the d-axis command current based on the difference from the output voltage value is further provided.

  In the above configuration, by providing the feedback means, the output voltage value can be more appropriately controlled so as to be within the allowable range.

  According to a thirteenth aspect of the present invention, there is provided a command voltage calculation means for calculating a command voltage for the d axis and the q axis for flowing a command current for the d axis and the q axis to the inverter, and an operation determined according to the command voltage. When the output voltage value of the inverter is larger than the threshold voltage, a limiting unit is provided that limits the output voltage value within the threshold voltage by correcting the command voltage without decreasing the d-axis command voltage. It is characterized by.

  When the operation output voltage value determined in accordance with the command voltage is larger than the threshold voltage, operating the inverter with this command voltage may cause inconvenience such as overmodulation control and lower controllability. For this reason, there is known a method of correcting the command voltage so that the calculated output voltage value is equal to or lower than the threshold voltage when the threshold voltage is exceeded. However, this may cause the d-axis command voltage to decrease, and thus the d-axis current increase rate may decrease. In this regard, in the above configuration, such a problem can be avoided because the d-axis command voltage is not reduced when the command voltage is corrected.

  According to a fourteenth aspect of the present invention, in the invention according to the thirteenth aspect, in order to feedback control the output voltage value within the allowable range, a d-axis command is determined based on a difference between the upper limit value of the allowable range and the output voltage value. Feedback means for correcting the voltage is further provided, and the limiting means corrects only the q-axis command voltage when the calculated output voltage value is larger than a threshold voltage.

  In the above configuration, when the q-axis current increases, the d-axis command voltage can be increased by the feedback means. When the output voltage value becomes larger than the threshold voltage, the command voltage on the q axis is corrected (reduced correction) to keep the command voltage on the d axis as it is, while keeping the output voltage value within the allowable range. It can be. For this reason, the output voltage value can be within an allowable range without hindering an increase in d-axis current.

  According to a fifteenth aspect of the present invention, in the thirteenth aspect of the present invention, when the output voltage value in the calculation is larger than a threshold voltage, the limiting means sets the output voltage value within the threshold voltage and the command voltage. The command voltage is corrected so as to change the phase of the vector to the negative side of the d-axis.

  In the above configuration, by changing the phase of the vector of the command voltage to the negative side of the d-axis while keeping the output voltage value within the threshold voltage, the output voltage value is within the threshold voltage while promoting the increase of the d-axis current. be able to.

  According to a sixteenth aspect of the present invention, in the fifteenth aspect of the invention, the change of the phase is performed by determining the upper limit value of the q-axis command voltage determined based on the operation output voltage value and the d-axis command voltage and the current q It is performed according to the difference from the command voltage of the shaft.

  From the d-axis command voltage and the threshold voltage, an upper limit value of the q-axis command voltage for setting the output voltage value within the threshold voltage can be calculated. For this reason, the upper limit value of the q-axis command voltage can be grasped based on these two values. The excess of the current q-axis command voltage relative to the upper limit value of the q-axis command voltage determines the amount of increase required for the d-axis current. In this regard, in the above configuration, the d-axis current can be appropriately increased by changing the phase according to the difference between the upper limit value of the q-axis command voltage and the current q-axis command voltage.

  According to a seventeenth aspect of the present invention, in the invention according to any one of the thirteenth to sixteenth aspects, the command voltage calculation means is configured to determine d based on a cumulative value of a difference between the command current and the actual current on the d axis and the q axis. Each of the command voltages for the axes and q-axis is calculated, and when the output voltage value in calculation is larger than a threshold voltage, the increase of the cumulative value is prohibited only for the q-axis.

  When the cumulative value is calculated at the time of restriction by the restriction means, it becomes an appropriate value when the q-axis command voltage is actually applied to the q-axis of the multiphase rotating machine, regardless of the restriction by the restriction means. Thus, the cumulative value will increase. For this reason, the accumulated value becomes excessive, and it becomes difficult to set the command voltage appropriately. In this regard, in the above configuration, such a problem can be avoided by prohibiting an increase in the cumulative value on the q axis when the restriction is performed.

  In particular, in the above configuration, since the d-axis is not limited by the limiting means, the accumulated value used for calculating the d-axis command voltage is desirably updated according to the difference between the command current and the actual current. In this respect, in the above configuration, since the increase in the accumulated value of the d-axis is not prohibited, the accumulated value of the d-axis can be set to an appropriate value, and the d-axis controllability can be kept good. can do.

  The invention according to claim 18 is the invention according to any one of claims 1 to 17, wherein the multiphase rotating machine is a surface magnet synchronous rotating machine.

  In the surface magnet synchronous rotating machine, the current vector that can generate the maximum torque with the minimum current is the current vector with the d-axis current set to zero. For this reason, it is desirable not to let a current flow through the d-axis as much as possible unless the computational output voltage value determined according to the command voltage exceeds the input voltage of the inverter. On the other hand, if the d-axis current is not passed until the output voltage value approximates the input voltage, it is difficult to increase the d-axis current rapidly when the output voltage value exceeds the input voltage. In this regard, if the manipulated variable calculation means is provided, the d-axis current can be increased rapidly, so that the d-axis current can be suppressed as much as possible until the output voltage value approximates the input voltage. Even when the limiting means is provided, the d-axis current can be increased rapidly, so that the d-axis current can be suppressed as much as possible until the output voltage value approximates the input voltage.

  The invention according to claim 19 is the invention according to any one of claims 1 to 18, wherein the multi-phase rotating machine is used as an actuator of an electric power steering.

  A power steering actuator is desired to have a particularly quick response to a required torque. In this regard, in the above configuration, by providing the operation amount calculating means and the limiting means, it is possible to quickly cope with an increase in the q-axis command current and, in turn, quickly cope with an increase in the required torque.

  According to a twenty-second aspect of the present invention, there is provided command voltage calculating means for calculating a command voltage for the d-axis and the q-axis for causing a command current for the d-axis and the q-axis to flow through the inverter, and the output voltage value is fed back within an allowable range. Feedback means for correcting the d-axis command voltage based on the difference between the upper limit value of the allowable range and the output voltage value to control, and the current flowing through the multiphase rotating machine as the q-axis command current increases And a means for increasing the d-axis current response immediately after the increase of the required torque to be higher than the q-axis current response.

  In the above configuration, the d-axis current response immediately after the increase of the q-axis command current is made higher than the q-axis current response, and as a result, the q-axis current can be rapidly increased.

  According to a twenty-first aspect of the present invention, in the invention according to any one of the first to twelfth and twentieth aspects, the q-axis command current is obtained based on a required torque.

  In the above configuration, by providing the operation amount calculating means and the limiting means, the actual q-axis current can be rapidly increased when the q-axis command current increases as the required torque increases.

  According to a twenty-second aspect of the present invention, when the current in the d-axis flowing through the multiphase rotating machine is changed as the required torque for the multiphase rotating machine is increased, the amount of change is maximized immediately after the increase of the required torque. It has the means to do, It is characterized by the above-mentioned.

  In the above configuration, in order to maximize the amount of change in the d-axis current flowing through the multiphase rotating machine as the required torque increases, immediately after the increase in the required torque, the field current is increased rapidly when the required torque increases. Can do. For this reason, the q-axis current can be increased rapidly, and as a result, it is possible to appropriately cope with the increase in the required torque.

  Note that the above means may function only in a region where the amplitude of the phase voltage applied to the multiphase rotating machine approximates a value twice the input voltage of the inverter.

(First embodiment)
Hereinafter, a first embodiment in which a control device for a multiphase rotating machine according to the present invention is applied to a control device for an electric motor as an actuator of an in-vehicle power steering will be described with reference to the drawings.

  FIG. 1 shows an overall configuration of an electric motor control system according to the present embodiment.

  As shown in the drawing, the electric motor 10 is a power steering actuator, and here, is constituted by a surface magnet synchronous motor (SPMSM). In power steering, torque generated by a handle operation (not shown) is detected, and a required torque Td is calculated accordingly.

  The two-phase converter 20 converts the three-phase actual currents iu, iv, and iw flowing through the motor 10 into a d-axis actual current id and a q-axis actual current iq based on the electrical angle θ of the motor 10. The q-axis current setting unit 22 calculates a q-axis command current iqc based on the required torque Td. Specifically, here, the command current iqc is calculated by multiplying the torque constant Kt by the required torque Td. Incidentally, the torque constant Kt is a product of the counter electromotive force constant of the electric motor 10 and the number of pole pairs.

  The deviation calculation unit 24 calculates the difference between the command current iqc and the q-axis actual current iq. The command voltage calculation unit 26 calculates a command voltage vqc for flowing the command current iqc based on the output of the deviation calculation unit 24. Specifically, here, the command voltage vqc is calculated by proportional-integral control based on the proportional gain Kpq and the integral gain Kiq.

  On the other hand, the deviation calculation unit 28 calculates a difference between a command current idc, which will be described later, with respect to the d-axis actual current id. The command voltage calculation unit 30 calculates a command voltage vdc for flowing the command current idc based on the output of the deviation calculation unit 28. Specifically, here, the command voltage vdc is calculated by proportional-integral control based on the proportional gain Kpd and the integral gain Kid.

  The three-phase conversion unit 32 converts the command voltages vdc, vqc into three-phase command voltages vuc, vvc, vwc based on the electrical angle θ of the electric motor 10. The PWM signal generation unit 34 generates an operation signal of the switching element of the inverter 36 for applying the command voltages vuc, vvc, vwc to each phase of the electric motor 10 based on the command voltages vuc, vvc, vwc, and outputs this To do. The inverter 36 supplies the electric power of the battery B to the electric motor 10 according to the operation signal.

Here, since the electric motor 10 of this embodiment is SPMSM as described above, the output of the electric motor 10 can be controlled so that the required torque Td is obtained only by the q-axis current. In particular, in SPMSM, since the maximum torque can be generated with the minimum current when the d-axis current is zero, basically, the d-axis command current idc is set to zero to perform the maximum torque control. . However, when the rotational speed ω of the electric motor 10 (more precisely, the rotational speed ω that is the time differential value of the electrical angle θ) increases, the induced voltage generated in the electric motor 10 increases. This is due to the following reason. The voltage equation on the dq axis is expressed by the following equation using the resistance R, d axis inductance Ld, q axis inductance Lq, and counter electromotive force constant Φ of the electric motor 10.

vd = (R + sLd) id−ωLq × iq (c1)
vq = (R + sLq) iq + ω (Φ + Ld × id) (c2)

In the above, the second term on the right side of the above formula (c2) is a term related to the induced voltage. As can be seen from the above equation, when the rotational speed ω increases, the absolute value of the second term on the right side of the above equation (c2) increases and the induced voltage increases. As a result, the voltage vq increases. However, the voltages vd and vq are limited by the input voltage of the inverter 36, that is, the voltage VB of the battery B. That is, the vector length “√ {(vd) ^ 2 + (vq) ^ 2}]” of the voltages vd and vq cannot be larger than “√ (3/8)” times the voltage VB of the battery B. . For this reason, in the high rotational speed region, field weakening control is performed to decrease the q-axis voltage vq by increasing the d-axis current (by making the d-axis current negative and increasing its absolute value). . As a result, the second term on the right side of the above equation (c2) can be reduced, and thus the voltage vq can be reduced. As a result, as shown in FIG. 2, it is possible to drive the electric motor 10 in the high rotation speed region as compared with the maximum torque control in which the d-axis current is zero.

  In the present embodiment, in order to perform the field weakening control, in this embodiment, the output voltage value of the inverter 36 determined in accordance with the command voltages vdc and vqc (the length of the vector of the command voltages vdc and vqc “√ {(vdc) ^ 2 + ( Feedback control is performed so that vqc) ^ 2} ") falls within the allowable range.

  That is, as shown in FIG. 1, the norm calculation unit 40 calculates the vector lengths of the command voltages vdc and vqc. The allowable voltage setting unit 42 calculates the allowable voltage Vom, which is the upper limit value of the allowable range, by multiplying the voltage VB of the battery B by the constant A. This allowable voltage Vom is set to a value equal to or less than “√ (3/8)” times the voltage VB of battery B. This is a setting for setting the amplitude of the command voltages vuc, vvc, and vwc to be equal to or lower than the voltage (“VB / 2”) that can be realized by the battery B. For this reason, the constant A is set to a value equal to or less than “√ (3/8)”. Here, from the viewpoint of giving priority to the maximum torque control as much as possible, it is desirable that the constant A be a value as large as possible. However, in order to quickly increase the d-axis current when the required torque Td is increased, it is desirable that the constant A be a small value. In view of these two requirements, the constant A is set. Incidentally, in this embodiment, the constant A is set to a value of about “0.9 × √ (3/8)”.

  The deviation calculation unit 44 calculates the difference of the allowable voltage Vom with respect to the vector length of the command voltages vdc and vqc. On the other hand, the voltage correction amount calculation unit 46 calculates a d-axis voltage correction amount ΔV based on the output of the deviation calculation unit 44. Here, the correction amount ΔV is calculated by proportional-integral control using the proportional gain Kp and the integral gain Ki. The feedback current calculation unit 48 calculates a d-axis command current (feedback current idb) as an operation amount of feedback control based on the correction amount ΔV. Here, the feedback current idb is calculated by dividing the correction amount ΔV by the multiplication value of the rotational speed ω and the d-axis inductance Ld. Here, the reason why the rotational speed ω is used in calculating the feedback current idb is that the q-axis voltage amount that can be reduced by the d-axis current depends on the rotational speed ω, as shown in the above equation (c2).

  Field weakening control can be performed by manipulating the d-axis command current in the feedback control. However, in this case, as shown in FIG. 3, the response of the feedback current idb is low. For this reason, if the required torque Td increases when the vector length of the command voltages vdc and vqc is in the vicinity of a value “√ (3/8)” times the voltage VB of the battery B, the q-axis actual current iq is reduced. It cannot be changed quickly. That is, in this case, although the command current iqc increases according to the required torque Td, in order to increase the q-axis actual current iq, first, the d-axis actual current id must be increased as a negative value. However, since the change in the command current idf is slow, the increase in the actual current id is also slow.

Therefore, in this embodiment, an open-loop control term for the d-axis command current idc, which is an operation amount for keeping the vector length of the command voltages vdc and vqc within the allowable voltage Vom, is provided. Specifically, as shown in FIG. 1 above, in the open loop term calculation unit 50, based on the command voltages vdc and vqc, the length of the vector of the command voltages vdc and vqc is set to fall within the allowable voltage Vom. A correction amount Δid of the command current idc is calculated. Here, when the d-axis current changes by the correction amount Δid, the q-axis voltage is considered to change simply by “ωLd × Δid” from the above equation (c2). As shown in FIG. 4, the condition for keeping the vector lengths of the command voltages vdc and vqc within the allowable voltage Vom by the correction amount Δid is expressed by the following equation (c3).

Vom = √ {(vdc) ^ 2 + (vqc + ωLd × Δid) ^ 2} (c3)

When the above equation (c3) is solved for the correction amount Δid, the following equation (c4) is obtained.

Δid = [√ {Vom ^ 2- (vdc) ^ 2} -vqc] / ωLd (c4)

In the open loop term calculation unit 50 shown in FIG. 1, the correction amount Δid is calculated by the above equation (c4). Then, the gain setting unit 52 calculates the open loop current idf by multiplying the correction amount Δid by the gain Kf. The strong field prohibiting unit 54 corrects the open loop current idf to zero when the open loop current idf is larger than zero. This is done to avoid this when the open loop current idf is larger than zero in view of the fact that it acts to increase the induced voltage in the above equation (c2). Further, the command current calculation unit 56 calculates the d-axis command current by adding the feedback current idb to the open loop current idf. Further, when the output of the command current calculation unit 56 is greater than zero, the strong field prohibition unit 58 corrects this to zero. This is also done to avoid this when the output is greater than zero in view of the effect of increasing the induced voltage in the above equation (c2). Thus, the final command current idc for the d axis is calculated.

  FIG. 5 shows a procedure of processing related to the calculation of the command currents idc and iqc. This process is repeatedly executed at a predetermined cycle by, for example, a microcomputer.

  In this series of processes, first, in step S10, a q-axis command current iqc is calculated based on the required torque Td. In the subsequent step S12, the command voltage vqc is calculated based on the command current iqc and the actual current iq. In the subsequent step S14, the command voltage vdc is calculated based on the command current idc and the actual current id. In step S16, the feedback current idb is calculated based on the command voltages vdc and vqc calculated in steps S12 and S14, the allowable voltage Vom and the rotational speed ω. Further, in step S18, the open loop current idf is calculated based on the command voltages vdc and vqc calculated in steps S12 and S14, the allowable voltage Vom and the rotational speed ω.

  In a succeeding step S20, it is determined whether or not the open loop current idf is smaller than zero. And when it is more than zero, the open loop current idf is set to zero. On the other hand, when an affirmative determination is made in step S20 or when the process of step S22 is completed, the process proceeds to step S24. In step S24, the command current idc at the next processing of this series of processing is the sum of the open loop current idf and the feedback current idb. In step S26, it is determined whether or not the command current idc is smaller than zero. If it is determined that the value is greater than or equal to zero, the command current idc is set to zero in step S28. When an affirmative determination is made in step S26 or when the process of step S28 is completed, this series of processes is temporarily terminated.

  According to the embodiment described in detail above, the following effects can be obtained.

  (1) When the required torque Td for the electric motor 4 increases, the operation amount for keeping the length of the vector (command voltage vector) of the command voltages vdc and vqc within the allowable voltage Vom is calculated by the open loop control. Thereby, compared with the case where the operation amount is calculated by feedback control, the operation amount can be calculated quickly, and the change amount of the operation amount immediately after the increase of the required torque Td can be increased. That is, in order to increase the amount of change in the operation amount immediately after the increase of the output torque by feedback control, it is necessary to increase the gains Kp and Ki. In this case, hunting is likely to occur. For this reason, depending on the feedback control, it is difficult to increase the amount of change in the operation amount immediately after the increase in the required torque Td.

  (2) The operation amount for keeping the command voltage vector within the allowable voltage Vom is the d-axis command current idc. As a result, the q-axis command voltage for allowing the q-axis current to flow according to the required torque Td can be suitably reduced, and the command voltage vector can be kept within the allowable voltage Vom. In the present embodiment, since the PWM control is performed using the voltage applied to each phase of the electric motor 10 as the command voltage, the operation amount is actually the command voltage. However, since this command voltage is determined from the command currents idc and iqc, the command current idc is defined as the manipulated variable here.

  (3) An upper limit value (√ {Vom ^ 2- (vdc) ^ 2}) of the q-axis command voltage vqc is calculated based on the allowable voltage Vom and the d-axis command voltage vdc, and the command voltage vqc and the upper limit value are calculated. Based on the difference, a correction amount Δid for the d-axis command current was calculated. Thereby, it is possible to appropriately calculate the correction amount Δid of the d-axis command current for setting the command voltage vector to be equal to or less than the allowable voltage Vom.

  (4) In calculating the open loop current idf, the rotational speed ω was used. Thereby, the required d-axis current can be calculated more appropriately.

  (5) In order to keep the command voltage vector within the allowable voltage Vom, the feedback current idb was calculated based on the difference between the length of the command voltage vector and the allowable voltage Vom. As a result, the command voltage vector can be more appropriately controlled so as to be within the allowable voltage Vom.

(Second Embodiment)
Hereinafter, the second embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  FIG. 6 shows an overall configuration of a control system of the electric motor 10 according to the present embodiment. In FIG. 6, the same members as those shown in FIG. 1 are given the same reference numerals for the sake of convenience.

  As illustrated, in the present embodiment, the open loop term calculation unit 60 calculates the open loop current idf based on the difference between the q-axis command current iqc and the actual current iq. This is due to the following reason.

  The reason why the vector lengths of the command voltages vdc and vqc exceed the allowable voltage Vom is considered to be that the q-axis command voltage vqc increases as the required torque Td increases. Therefore, if the expansion of the vector due to the increase in the q-axis command voltage vqc can be compensated by the increase in the d-axis current, the vector length of the command voltages vdc and vqc can be made equal to or less than the allowable voltage Vom. it is conceivable that. On the other hand, the increase in the q-axis command voltage vqc is caused by the increase in the q-axis command current iqc. Therefore, it is considered that the d-axis current for compensating for the extension of the vector length can be calculated according to the difference of the command current idc with respect to the q-axis actual current id.

Particularly in this embodiment, since the command voltage calculation unit 26 performs proportional-integral control, the increase amount Δvqc of the command voltage vqc immediately after the command current iqc increases is approximated by “Kpq (iqc−iq)”. Can do. On the other hand, the q-axis voltage amount that can be reduced by the open loop current idf is “ωLd × idf”. From the above, the open loop term calculation unit 60 calculates the open loop current idf by the following equation (c5).

idf = KF (iqc−iq) / ωLd (c5)

The gain KF in the above equation (c5) may be the same as the proportional gain Kpq, but may be different from this.

  FIG. 7 shows a procedure of processing related to the calculation of the command currents idc and iqc. This process is repeatedly executed at a predetermined cycle by, for example, a microcomputer.

  In this series of processes, first, in step S30, a q-axis command current iqc is calculated based on the required torque Td. In the subsequent step S32, the command voltage vqc is calculated based on the command current iqc and the actual current iq. In the subsequent step S34, an open loop current idf is calculated based on the command current iqc, the actual current iq, and the rotational speed ω. In a succeeding step S36, it is determined whether or not the open loop current idf is smaller than zero. If it is equal to or greater than zero, the open loop current idf is set to zero in step S38. On the other hand, when an affirmative determination is made in step S36, or when the process of step S38 is completed, the process proceeds to step S40.

  In step S40, the command current idc is the sum of the open loop current idf and the feedback current idb. In step S42, it is determined whether or not the command current idc is smaller than zero. If it is determined that the value is greater than or equal to zero, the command current idc is set to zero in step S44. When an affirmative determination is made at step S42 or when the processing at step S44 is completed, the routine proceeds to step S46. In step S46, command voltage vdc is calculated based on command current idc and actual current id. In step S48, based on the command voltages vdc and vqc calculated in steps S32 and S46, the allowable voltage Vom, and the rotation speed ω, the feedback current idb at the next processing of this series of processing is calculated. When the process of step S48 is completed, this series of processes is temporarily terminated.

  According to the present embodiment described above, in addition to the effects (1), (2), (4), and (5) of the first embodiment, the following effects can be obtained. .

  (6) The open loop current idf was calculated based on the difference between the command current iqc and the actual current iq on the q axis. Thereby, the open loop current idf can be calculated by a simple method. In particular, in the present embodiment, since the q-axis command voltage vqc is calculated based on the difference between the command current iqc and the actual current iq on the q-axis, the command on the q-axis is calculated based on the difference between the command current iqc and the actual current iq. This method is effective because the increase amount of the voltage vqc can be grasped with high accuracy.

(Third embodiment)
Hereinafter, the third embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  As described above, when the required torque Td increases, the response of the feedback current idb is slow, and as a result, the response of the actual current id is delayed. Here, in the above embodiment, the response of the actual current id is increased by increasing the response of the command current idc. On the other hand, in this embodiment, as shown in FIG. 8, it is considered that the actual current id quickly follows the feedback current idb. As shown in FIG. 9, this can be done by giving priority to the increase of the actual current id when the command current iqc is increased. In other words, the command currents idc and iqc are based on the above equation (c1) under the condition that the length of the voltage vector (vd, vq) is a value “√ (3/8)” times the voltage VB of the battery B. ) And (c2) are related to each other and are limited to a circle determined. As shown, this circle has a center coordinate (Φ / Ld, 0) and a radius “{√ (3/8)} VB / ω”. Here, the q-axis current cannot be increased in the manner indicated by the broken line in the figure, but the q-axis current can be increased by increasing the d-axis current once.

  As shown in FIG. 9, increasing the d-axis current is effective in increasing the q-axis current, but setting for maintaining high controllability is an obstacle to increasing the d-axis current. Sometimes. That is, when the length of the vector determined by the command voltages vdc and vqc exceeds a value “√ (3/8)” times the voltage VB of the battery B, the command voltages vqc and vdc are applied to the motor 10 via the inverter 36. I can't do it. For this reason, when integral control is performed when calculating the command voltages vdc and vqc, the absolute value of the integral term becomes excessively large, and as a result, the controllability of the voltage applied to the electric motor 10 is lowered. Therefore, from the viewpoint of maintaining high controllability, when the length of the vector determined by the command voltages vdc and vqc exceeds a value “√ (3/8)” times the voltage VB of the battery B, the command voltage vdc, There is a case where the length of the vector determined by vqc is limited to a value that is “√ (3/8)” times the voltage VB and the update of the integral term is prohibited. However, according to this process, there is a risk that even the command voltage vdc that is originally to be preferentially increased may be reduced. For this reason, the increase of the d-axis current is delayed, and as a result, the q-axis current cannot be increased rapidly.

  Therefore, in this embodiment, when the length of the vector determined by the command voltages vdc and vqc is larger than the threshold voltage Vm, the command voltage vector length becomes the threshold voltage Vm while fixing the d-axis command voltage vdc. To correct. FIG. 10 shows an overall configuration of a control system for the electric motor 10 according to the present embodiment. In FIG. 10, members corresponding to those shown in FIG. 1 are given the same reference numerals for convenience.

  As illustrated, the present embodiment includes a limiting unit 70 that limits the length of a vector determined by the command voltages vdc and vqc within the threshold voltage Vm. Here, the threshold voltage Vm is set by multiplying the voltage of the battery B by a constant C in the threshold voltage setting unit 72. Here, the constant C is desirably set to a value equal to or greater than the constant A. In other words, the threshold voltage Vm is preferably equal to or higher than the allowable voltage Vom. In the present embodiment, the constant C is set to “√ (3/8)”. This makes it possible to avoid limiting the length of the vector determined by the command voltages vdc and vqc until the maximum voltage that can be applied to the electric motor 10 is reached. For this reason, control based on the command voltages vdc and vqc can be performed satisfactorily. When the vector length determined by the command voltages vdc and vqc exceeds the threshold voltage Vm, the vector length can be reduced by correcting the decrease of the q-axis command voltage vqc without correcting the d-axis command voltage vdc. Let this be the threshold voltage Vm. Further, at this time, the update of the integral term in the command voltage calculation unit 26 is prohibited.

  FIG. 11 shows a procedure of processing related to calculation of the command currents idc and iqc according to the present embodiment. This process is repeatedly executed at a predetermined cycle by, for example, a microcomputer.

  In this series of processes, first, in step S50, a q-axis command current iqc is calculated based on the required torque Td. In the subsequent step S52, the command voltage vqc is calculated based on the command current iqc and the actual current iq. In the subsequent step S54, the command voltage vdc is calculated based on the command current idc and the actual current id. In step S56, it is determined whether or not the length of the vector determined by the command voltages vdc and vqc calculated in steps S12 and S14 exceeds the threshold voltage Vm. When it is determined that the threshold voltage Vm is exceeded, in step S58, correction is performed so that the length of the vector determined by the command voltages vdc and vqc is the threshold voltage Vm. Here, the square root of the value obtained by subtracting the square of the d-axis command voltage vdc from the square of the threshold voltage Vm is taken as the q-axis command voltage vqc, and the d-axis command voltage vdc is left as it is. At this time, the calculation of the integral term used when calculating the q-axis command voltage vqc is prohibited. Specifically, the update of the integral term at the time of calculating the q-axis command voltage vqc is invalidated. As a result, the integral term used for calculating the q-axis command voltage vqc is held at a value before the vector length is limited. On the other hand, when it is determined in step S56 that the voltage is equal to or lower than the threshold voltage Vm, or when the process of step S58 is completed, the process proceeds to step S60. In step S60, the next feedback current idb in the next process of this series of processes is calculated based on the allowable voltage Vom, the rotational speed ω, and the command voltages vdc and vqc. Subsequently, in step S62, it is determined whether or not the feedback current idb is smaller than zero. If it is determined that the value is greater than or equal to zero, the feedback current idb is set to zero in step S64. When an affirmative determination is made in step S62 or when the process of step S64 is completed, this series of processes is temporarily terminated.

  According to the embodiment described above in detail, the following effects can be obtained in addition to the effects (1) to (5) of the first embodiment.

  (7) When the length of the vector determined by the command voltages vdc and vqc is larger than the threshold voltage Vm, the length of the vector is reduced by correcting the command voltages vdc and vqc without decreasing the d-axis command voltage vdc. It was limited within the threshold voltage Vm. Thereby, when the length of the vector exceeds the threshold voltage Vm, it is possible to avoid a possibility that the increasing speed of the d-axis current is lowered.

  (8) When the length of the vector determined by the command voltages vdc and vqc is larger than the threshold voltage Vm, the q-axis command voltage vqc is reduced and corrected without correcting the d-axis command voltage vdc. Thereby, the length of the vector can be within the allowable voltage Vom without hindering an increase in d-axis current.

  (9) The command voltages vdc and vqc for the d-axis and the q-axis are calculated based on the cumulative value (integral term) of the difference between the command currents idc and iqc and the actual currents id and iq, and are determined by the command voltages vdc and vqc. When the vector length is larger than the threshold voltage Vm, an increase in the absolute value of the integral term is prohibited only for the q axis. Thereby, it is possible to avoid a decrease in controllability of the command voltage vqc. Further, since the command voltage vdc is not limited for the d-axis, the integral term used to calculate the command voltage vdc for the d-axis may be updated according to the difference between the command current idc and the actual current id. desirable. In this respect, in this embodiment, since the increase of the d-axis integral term is not prohibited, the d-axis integral term can be set to an appropriate value, and the d-axis controllability can be improved. Can be maintained.

(Fourth embodiment)
Hereinafter, the fourth embodiment will be described with reference to the drawings with a focus on differences from the third embodiment.

  FIG. 12 shows an overall configuration of a control system for the electric motor 10 according to the present embodiment. In FIG. 12, members corresponding to those shown in FIG. 10 are given the same reference numerals for convenience.

  As illustrated, the present embodiment includes a limiting unit 74 that limits the length of a vector determined by the command voltages vdc and vqc within the threshold voltage Vm. The limiting unit 74 changes the phase of the vector to the negative side of the d-axis while setting the length of the vector determined by the command voltages vdc and vqc to the threshold voltage Vm.

  FIG. 13 shows a procedure of processing related to calculation of the command currents idc and iqc according to the present embodiment. This process is repeatedly executed at a predetermined cycle by, for example, a microcomputer.

In this series of processing, first, in steps S70 to S76, step S in FIG.
The same processing as the processing of 50 to S56 is performed. If it is determined in step S76 that the length of the vector determined by the command voltages vdc and vqc exceeds the threshold voltage Vm, the length of the vector determined by the command voltages vdc and vqc is determined in step S78. To correct.

  Here, the value obtained by subtracting the command voltage vqc from the square root of the value obtained by subtracting the square of the d-axis command voltage vdc from the square of the threshold voltage Vm is multiplied by the gain Kθ to obtain the vector phase correction amount Δθ. Is calculated. Then, the phase φ of the vector determined by the command voltages vdc and vqc is corrected to “φ + Δθ” and the length thereof becomes the threshold voltage Vm. At this time, as in step S58 of FIG. 11, the integral term used for calculating the q-axis command voltage vqc is prohibited.

  When the process of step S78 is completed, the processes of steps S80 to S84 are performed in the same manner as steps S60 to S64 of FIG.

  According to this embodiment detailed above, the effects (1) to (5) of the previous first embodiment and the effects (7) and (9) of the previous third embodiment are achieved. In addition, the following effects can be obtained.

  (10) When the vector lengths of the command voltages vdc and vqc are larger than the threshold voltage Vm, the command voltages vdc and vqc are set to change the phase of the vector to the negative side of the d-axis while setting the length to the threshold voltage Vm. Corrected. Thereby, the length of the vector can be set to the threshold voltage Vm while promoting the increase of the d-axis current.

  (11) The phase was changed according to the difference between the upper limit value of the q-axis command voltage vqc determined based on the d-axis command voltage vdc and the threshold voltage Vm and the current q-axis command voltage vqc. Thereby, the d-axis current can be appropriately increased.

(Fifth embodiment)
Hereinafter, the fifth embodiment will be described with reference to the drawings with a focus on differences from the third embodiment.

  In FIG. 14, the whole structure of the control system of the electric motor 10 concerning this embodiment is shown. In FIG. 14, members corresponding to those shown in FIG. 10 and the like are given the same reference numerals for the sake of convenience.

  As shown in the figure, in this embodiment, the length of the vector determined by the limiting unit 70 in the previous third embodiment, that is, the command voltages vdc and vqc, is added to the threshold voltage Vm in the configuration of the first embodiment. The limiting part 70 which restricts inside is provided. As a result, the d-axis current can be increased more quickly, and the q-axis current can be increased more quickly.

  FIG. 15 shows the experimental results of the d-axis and q-axis current responsiveness according to the present embodiment. In this figure, the final command currents idc and iqc that have increased in response to an increase in the required torque are normalized to “100%”, and the changes in the actual currents id and iq are plotted.

  As shown in the figure, when the command current iqc changes abruptly (stepwise), first, the actual current id on the d axis rises. Thus, by increasing the response of the d-axis actual current id, the response of the q-axis actual current iq can also be increased. In particular, when the actual currents id and iq change due to the contribution of the open loop current idf and the like, the amount of change in the d-axis actual current id is maximized immediately after the required torque Td is increased (immediately after the command current iqc is increased). . Further, by limiting the length of the voltage vector without correcting the d-axis command voltage vdc and prohibiting the q-axis integral calculation, the overshoots of the actual currents id and iq are suitably suppressed. be able to. In FIG. 15, the overshoot amount is suppressed to about 15%. However, the inventors have found that it is easy to set the overshoot amount to “25%” or less under any circumstances. Has been found.

  According to the present embodiment described above, each effect of the first embodiment and the third embodiment can be obtained, and the responsiveness of the q-axis actual current as the required torque Td increases. Can be further enhanced.

(Sixth embodiment)
Hereinafter, the sixth embodiment will be described with reference to the drawings with a focus on differences from the second embodiment.

  FIG. 16 shows the overall configuration of the control system of the electric motor 10 according to the present embodiment. In FIG. 16, members corresponding to those shown in FIG. 10 and the like are given the same reference numerals for the sake of convenience.

  As shown in the figure, in this embodiment, the length of a vector determined by the limiting unit 70 in the previous third embodiment, that is, the command voltages vdc and vqc, is added to the threshold voltage Vm in the configuration of the previous second embodiment. The limiting part 70 which restricts inside is provided. This also makes it possible to increase the d-axis current more quickly, and consequently increase the q-axis current more quickly.

(Seventh embodiment)
Hereinafter, the seventh embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  In FIG. 17, the whole structure of the control system of the electric motor 10 concerning this embodiment is shown. In FIG. 12, members corresponding to those shown in FIG. 10 are given the same reference numerals for convenience.

  As shown in the figure, in the present embodiment, as an operation amount for keeping the vector lengths of the command voltages vdc and vqc within the allowable voltage Vom, the correction amount of the d-axis command voltage vdc ( Open loop voltage vdf) is calculated. That is, in this embodiment, the open loop term calculation unit 50a calculates a value obtained by subtracting the command voltage vqc from the square root of the value obtained by subtracting the square of the command voltage vdc from the square of the allowable voltage Vom. The open loop voltage vdf is calculated by multiplying this value by the gain Kv. Then, the adder 82 calculates the sum of the open loop voltage vdf and the command voltage vdc output from the command voltage calculator 30, and this is the final command voltage.

  Also according to the present embodiment described above, it is possible to obtain an effect according to the above-described effect of the first embodiment.

(Other embodiments)
Each of the above embodiments may be modified as follows.

  In the third to sixth embodiments, when the length of the vector determined by the command voltages vdc and vqc is limited within the threshold voltage Vm, the update of the q-axis integral calculation is prohibited, but this is not limitative. For example, the integral term may be reset.

  In the configuration of the seventh embodiment, the length of the vector determined by the command voltages vdc and vqc is corrected within the threshold voltage Vm by correcting only the limiter 70 in the previous third embodiment, that is, the command voltage vqc. You may provide the restriction | limiting part 70 to restrict | limit.

  In the configuration of the first, second, and seventh embodiments, the length of the limiting unit 74 in the previous fourth embodiment, that is, the phase of the vector determined by the command voltages vdc and vqc is set to the negative side of the d axis. A limiting unit 74 that limits the threshold voltage Vm may be provided.

The calculation method by open loop control of the command current idc as the operation amount for keeping the length of the vector determined by the command voltages vdc and vqc within the allowable voltage Vom is exemplified in the first and second embodiments. Not limited to things. For example, based on the above formulas (c1) and (c2), the d-axis current id for the length of the voltage vector (vd, vq) to be the allowable voltage Vom is calculated as the following formula without using an approximate formula. May be.

id = [√ {Vom ^ 2− (Rid + sLdid−ωLqiq) ^ 2} − (R + sLq) iq−ωΦa] / ωLd

The method for calculating the command voltage vdc is not limited to the one exemplified in the above embodiment. For example, it may be a proportional term based on the difference between the command current idc and the actual current id, or may be the sum of a proportional term, an integral term, and a derivative term. Furthermore, in order to perform non-interference control, the second term of the above formula (c1) may be calculated based on the q-axis actual current iq and added to the feedback term.

  The calculation method of the command voltage vqc is not limited to the one exemplified in the above embodiment. For example, it may be a proportional term based on the difference between the command current iqc and the actual current iq, or may be the sum of a proportional term, an integral term, and a differential term. Furthermore, in order to perform non-interference control, the second term of the above formula (c2) may be calculated based on the actual current id of the d axis and added to the feedback term.

  The setting of the allowable voltage Vom and the threshold voltage Vm is not limited to the above setting. However, the allowable voltage Vom is preferably equal to or lower than the threshold voltage Vm, and more preferably, the allowable voltage Vom is smaller than the threshold voltage Vm. Further, it is desirable that these allowable voltage Vom and threshold voltage Vm have a value not more than “√ (3/8)” times the voltage VB of battery B. However, in view of the fact that the controllability by overmodulation PWM control can be ensured up to a value of “1.28” times the value of “√ (3/8)” times the voltage VB of the battery B, the threshold value The voltage Vm may be less than or equal to this value.

  In each of the above-described embodiments, the present invention is applied when the q-axis command current increases as the required torque increases. However, the present invention is not limited to this. For example, when the rotational speed is controlled as desired, the output is important. It is sufficient that the q-axis command current is increased by controlling the change to a desired value.

  In each of the above embodiments, the electric motor 10 is used as an actuator for power steering. However, the electric motor 10 is not limited to this, and may be used as a prime mover for a hybrid vehicle or an electric vehicle, for example.

  The electric motor 10 is not limited to a surface magnet synchronous motor, and may be, for example, an embedded magnet synchronous motor.

  -As a multiphase rotating machine, not only an electric motor but a generator may be sufficient.

The figure which shows the whole structure of the control system of the electric motor concerning 1st Embodiment. The figure which shows the expansion effect of the driving | operation possible rotation area | region by field weakening control. The time chart explaining the setting method of the d-axis command current according to the embodiment. The figure explaining the setting method of the d-axis command current concerning the embodiment. The flowchart which shows the procedure of the setting process of the command current of the dq axis concerning the embodiment. The figure which shows the whole structure of the control system of the electric motor concerning 2nd Embodiment. The flowchart which shows the procedure of the setting process of the command current of the dq axis concerning the embodiment. The time chart explaining the d-axis current control method according to the third embodiment. The figure explaining the ideal d-axis current control method. The figure which shows the whole structure of the control system of the electric motor concerning 3rd Embodiment. The flowchart which shows the procedure of the setting process of the command current of the dq axis concerning the embodiment. The figure which shows the whole structure of the control system of the electric motor concerning 4th Embodiment. The flowchart which shows the procedure of the setting process of the command current of the dq axis concerning the embodiment. The figure which shows the whole structure of the control system of the electric motor concerning 5th Embodiment. The time chart which shows the responsiveness of the dq-axis current concerning the embodiment. The figure which shows the whole structure of the control system of the electric motor concerning 6th Embodiment. The figure which shows the whole structure of the control system of the electric motor concerning 7th Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Electric motor, 26, 30 ... Command voltage calculation part, 50, 50a, 60 ... Open loop term calculation part, 70, 74 ... Restriction part.

Claims (22)

In the control device for a multi-phase rotating machine that controls the output of the multi-phase rotating machine by operating the switching element of the inverter,
Command voltage calculating means for calculating a command voltage for the d-axis and the q-axis for flowing a command current for the d-axis and the q-axis to the inverter;
An operation amount calculating means for calculating an operation amount for keeping an output voltage value of the inverter within an allowable range within an allowable range when the q-axis command current increases according to the command voltage by open loop control; A control device for a multi-phase rotating machine.   2. The control device for a multi-phase rotating machine according to claim 1, wherein the operation amount to be within the allowable range is a d-axis command current.   The operation amount calculation means includes means for calculating an upper limit value of the q-axis command voltage based on the upper limit value of the allowable range and the d-axis command voltage, and the command voltage on the q-axis is larger than the upper limit value. The controller for a multi-phase rotating machine according to claim 2, wherein the command current for the d-axis is calculated based on the difference between the two.   3. The control device for a multi-phase rotating machine according to claim 2, wherein the manipulated variable calculation means calculates the d-axis command current based on a difference between the command current and the actual current in the q-axis.   5. The control device for a multi-phase rotating machine according to claim 3, wherein the operation amount calculating means uses a rotation speed of the multi-phase rotating machine in calculating the d-axis command current. 6.   Limiting means for limiting the output voltage value within the threshold voltage by correcting the command voltage without decreasing the d-axis command voltage when the arithmetic output voltage value is greater than the threshold voltage. The control device for a multi-phase rotating machine according to any one of claims 1 to 5.   7. The control device for a multi-phase rotating machine according to claim 6, wherein the limiting means corrects only the q-axis command voltage when the calculated output voltage value is larger than a threshold voltage.   The limiting means is configured to change the phase of the command voltage vector to the negative side of the d-axis while keeping the output voltage value within the threshold voltage when the calculated output voltage value is greater than the threshold voltage. The control device for a multi-phase rotating machine according to claim 6, wherein the voltage is corrected.   9. The phase change is performed according to a difference between an upper limit value of a q-axis command voltage determined based on a d-axis command voltage and the threshold voltage and a current q-axis command voltage. The control apparatus of the multiphase rotating machine of description.   The command voltage calculating means calculates each command voltage for the d-axis and the q-axis based on a cumulative value of the difference between the command current and the actual current for the d-axis and the q-axis, and the calculation output 10. The control device for a multi-phase rotating machine according to claim 6, wherein when the voltage value is larger than a threshold voltage, the increase of the cumulative value is prohibited only for the q-axis.   The control device for a multi-phase rotating machine according to any one of claims 5 to 10, wherein an upper limit value of the allowable range is set to be equal to or lower than the threshold voltage.   Feedback means for operating a d-axis command current based on a difference between an upper limit value of the allowable range and the calculated output voltage value so that the calculated output voltage value falls within the allowable range. The control device for a multiphase rotating machine according to any one of claims 1 to 11. In the control device for a multi-phase rotating machine that controls the output of the multi-phase rotating machine by operating the switching element of the inverter,
Command voltage calculating means for calculating a command voltage for the d-axis and the q-axis for flowing a command current for the d-axis and the q-axis to the inverter;
When the output voltage value of the inverter determined in accordance with the command voltage is larger than the threshold voltage, the output voltage value is corrected by correcting the command voltage without reducing the d-axis command voltage. A control device for a multi-phase rotating machine, comprising limiting means for limiting the voltage. Feedback means for correcting a command voltage for the d-axis based on a difference between an upper limit value of the allowable range and the output voltage value in order to feedback control the output voltage value within the allowable range;
14. The control device for a multi-phase rotating machine according to claim 13, wherein the limiting means corrects only the q-axis command voltage when the calculated output voltage value is larger than a threshold voltage.   The limiting means is configured to change the phase of the command voltage vector to the negative side of the d-axis while keeping the output voltage value within the threshold voltage when the calculated output voltage value is greater than the threshold voltage. 14. The control device for a multi-phase rotating machine according to claim 13, wherein the voltage is corrected.   The phase change is performed in accordance with a difference between an upper limit value of a q-axis command voltage determined based on an output voltage value in calculation and a d-axis command voltage and a current q-axis command voltage. The control device for a multiphase rotating machine according to claim 15.   The command voltage calculating means calculates each command voltage for the d-axis and the q-axis based on a cumulative value of the difference between the command current and the actual current for the d-axis and the q-axis, and the calculation output The control device for a multi-phase rotating machine according to any one of claims 13 to 16, wherein when the voltage value is larger than a threshold voltage, an increase in the cumulative value is prohibited only for the q-axis.   The control device for a multiphase rotating machine according to any one of claims 1 to 17, wherein the multiphase rotating machine is a surface magnet synchronous rotating machine.   The control device for a multi-phase rotating machine according to any one of claims 1 to 18, wherein the multi-phase rotating machine is used as an actuator for an electric power steering. In the control device for a multi-phase rotating machine that controls the output of the multi-phase rotating machine by operating the switching element of the inverter,
Command voltage calculating means for calculating a command voltage for the d-axis and the q-axis for flowing a command current for the d-axis and the q-axis to the inverter;
Feedback means for correcting the d-axis command voltage based on the difference between the upper limit value of the allowable range and the output voltage value in order to feedback-control the output voltage value within the allowable range;
Means for increasing the response of the d-axis current immediately after the increase of the required torque to be higher than the response of the q-axis current when the current flowing through the multiphase rotating machine is changed with the increase of the q-axis command current; A control device for a multi-phase rotating machine.   The control device for a multi-phase rotating machine according to any one of claims 1 to 12, wherein the q-axis command current is obtained based on a required torque. In the control device for a multi-phase rotating machine that controls the output torque of the multi-phase rotating machine by operating the switching element of the inverter,
And a means for maximizing the amount of change immediately after the increase of the required torque when changing the current in the d-axis flowing through the multi-phase rotary machine as the required torque of the multi-phase rotary machine increases. Control device for multi-phase rotating machines.

Images