JP2008236853A - Control device of rotating machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that the responsiveness of control likely deteriorates at an operation of a high-modulation rate, when controlling the rotating state of a rotating machine by operating an output voltage of an inverter applied to the rotating machine. <P>SOLUTION: An actual difference of voltages (voltage differences ΔVd, ΔVq) with respect to a voltage to be outputted to a motor 10 in order to make command currents idc, iqc flow is calculated by inputting differences between actual currents id, iq flowing in the motor 10 and the command currents idc, iqc into a voltage equation. In a d-axis integration operation part 46 and a q-axis integration operation part 48, command voltages Vdc1, Vqc1 are calculated by integration operations of the voltage differences ΔVd, ΔVq, respectively. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a control device for a rotating machine that controls the rotation state of the rotating machine by manipulating an output voltage of an inverter with respect to the rotating machine.

  As this type of control device, for example, as seen in Patent Document 1 below, the command voltage on the dq axis for the inverter is calculated by proportional integration based on the difference between the command current on the dq axis and the actual current. A control device for a three-phase motor has also been proposed. Then, after the command voltage on the dq axis is converted into a three-phase command voltage, the output voltage of the inverter is manipulated based on this command voltage. However, the output voltage of the inverter is limited by the input voltage of the inverter. That is, when the command voltage of the inverter exceeds the input voltage of the inverter, the output voltage of the inverter cannot be used as the command voltage. At this time, if the integral calculation is continued, the absolute value of the integral term may become excessive.

Therefore, in the above control device, when the command voltage on the dq axis exceeds the limit value, the integral calculation for increasing the command voltage on the dq axis is stopped. Thereby, it can be avoided that the absolute value of the integral term becomes excessive.
JP 2006-296116 A

  Incidentally, the command voltage on the dq axis exceeds the limit value mainly in the high rotation speed region of the electric motor. In the high rotational speed region, it is desired to advance the phase of the command voltage vector on the dq axis in order to flow a desired current through the q axis. However, in the above control device, it is possible to prevent the absolute value of the integral term from becoming excessive by stopping the integral calculation, but the command when the command voltage on the dq axis is close to the limit value. It was difficult to advance the phase of the voltage vector quickly. For this reason, there is a problem that the responsiveness of the actual current to the command current is lowered, and as a result, the responsiveness of the control of the rotation state (rotation speed, torque, etc.) of the rotating machine is lowered.

  The present invention has been made in order to solve the above-mentioned problems, and its purpose is to increase the control responsiveness when controlling the rotation state of the rotating machine by manipulating the output voltage of the inverter with respect to the rotating machine. It is an object of the present invention to provide a control device for a rotating machine that can handle the above.

  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, dq to be output to the rotating machine in order to flow the command current based on the d-axis and q-axis command currents of the rotating machine and the actual currents of the d-axis and the q-axis. A voltage deviation calculating means for calculating a deviation of an actual voltage with respect to a voltage on the shaft, and an operating means for operating the output voltage so as to reduce the calculated deviation.

  When the output voltage of the inverter changes near the limit value determined according to the input voltage, it is necessary to advance the phase of the voltage vector. Here, the voltage deviation is noticeably generated on the side where the phase of the voltage vector is advanced. In other words, it indicates that the voltage on the d-axis is insufficient. In this respect, in the above-described invention, by operating the output voltage so as to reduce the deviation of the calculated voltage, the vector phase of the output voltage can be rapidly advanced, and thus the responsiveness of the output control can be improved. .

  According to a second aspect of the present invention, in the first aspect of the invention, the voltage deviation calculating means calculates the voltage deviation based on a voltage equation that converts the current on the dq axis into a voltage on the dq axis. It is characterized by that.

  In the said invention, the deviation of a voltage can be calculated appropriately by using a voltage equation.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the operating means calculates a command voltage for the inverter based on a plurality of values that vary in time series about the calculated deviation. Voltage calculating means is provided, and the output voltage of the inverter is operated based on the command voltage.

  In the above invention, in order to calculate the command voltage for the inverter based on a plurality of values that change in time series, the command voltage can be set in consideration of the voltage deviation history and the like.

  According to a fourth aspect of the present invention, in the third aspect of the invention, the command voltage calculation means calculates the command voltage based on the means for calculating a cumulative value of the deviation of the calculated voltage. Means.

  The accumulated value is a constant value when the operating state of the rotating machine is steady, and the value corresponds to a value required to make the voltage deviation zero. For this reason, in the said invention, in the steady state, the command voltage from which the voltage deviation is always zero can be set.

  According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the command voltage calculation means includes the means for calculating an actual output voltage on the dq axis based on the actual current on the dq axis, and the calculation. And a means for correcting the command voltage according to the actual output voltage.

  In the above invention, the degree of freedom of control such as gain setting can be improved by providing means for correcting the command voltage calculated based on the accumulated value.

  According to a sixth aspect of the present invention, in the fourth or fifth aspect of the present invention, when the length of the command voltage vector calculated by the command voltage calculating means exceeds a limit voltage, the limiting means limits the calculation of the cumulative value. Is further provided.

  The output voltage of the inverter is limited by the input voltage of the inverter. For this reason, when the length of the command voltage vector is greater than or equal to a predetermined length, the output voltage of the inverter cannot be used as the command voltage. At this time, the output voltage may not correspond to the accumulated value, and the accumulated value may not be correctly reflected in the control. In this case, the absolute value of the cumulative value may become excessively large. In this regard, in the above invention, such a problem can be avoided by providing the limiting means.

  The invention according to claim 7 is the invention according to claim 6, wherein when the length of the command voltage vector calculated by the command voltage calculation means exceeds the limit voltage, the limiting means has a d-axis component of the cumulative value. And a prohibiting means for prohibiting calculation of the increasing direction of the absolute value of the q-axis component.

  In the above invention, prohibiting an increase in the absolute value of the accumulated value of the d-axis component and the q-axis component can prevent the absolute value of the accumulated value from becoming excessively large.

  According to an eighth aspect of the present invention, in the sixth aspect of the present invention, when the length of the command voltage vector calculated by the command voltage calculation unit exceeds the limit voltage, the limiting unit converts the command voltage to the vector. And a means for forcibly changing the accumulated value in accordance with the corrected command voltage.

  The corrected command voltage reflects the actual output voltage of the inverter because the length of the vector is not more than the limit voltage. Therefore, if the accumulated value is corrected according to the command voltage, it is possible to avoid the accumulated value from becoming an inappropriate value.

  According to a ninth aspect of the invention, in the invention according to any one of the first to eighth aspects, prior to inputting the command current and the actual current to the voltage deviation calculating means, a low pass having the same characteristics for both of them. A filtering process using a filter is performed.

  Since the high-frequency noise is mixed in the real current compared with the cycle of the real current in the rotating coordinate system, it is desirable to remove the noise by filtering this. However, in this case, the actual current after the filter processing tends to be delayed. If a delay occurs between the command current and the actual current, it becomes difficult to calculate the voltage deviation with high accuracy. This decrease in the calculation accuracy of the deviation becomes particularly noticeable as the rotational speed of the rotating machine becomes higher. In this regard, in the above-described invention, the delay amount of the command current and the actual current can be made the same by applying the filtering process with the same characteristics to both the command current and the actual current, and thus the calculation accuracy of the voltage deviation is improved. It can be kept high regardless of the rotating speed of the rotating machine.

  A tenth aspect of the present invention is the method according to any one of the first to ninth aspects, further comprising means for acquiring a rotation angle and a rotation speed of the rotating machine, wherein the operation means is configured to calculate the calculated voltage. Command voltage calculation means for calculating a command voltage on the dq axis so as to reduce the deviation, and the amount of rotation of the rotating machine in the time from the acquisition timing of the rotation angle to the timing of updating the output voltage of the inverter A means for calculating based on the obtained rotation speed, and a command voltage on the dq axis based on an angle advanced by the amount of rotation with respect to the obtained rotation angle as a command voltage for each phase of the inverter. Converting means, and operating the output voltage based on the command voltage of each phase.

  When converting the command voltage on the dq axis to the command voltage of each phase of the inverter, when the acquired rotation angle is directly used, the rotation angle acquisition timing and the inverter output voltage update timing In the meantime, the rotating machine rotates. For this reason, if the output voltage converted by directly using the obtained rotation angle is used, the output voltage is delayed with respect to an appropriate value. In this regard, in the above invention, the output voltage is changed according to the rotation angle by performing conversion using the rotation angle that is advanced by the rotation amount rather than the rotation angle acquired in anticipation of the timing at which the output voltage is updated. More appropriate.

  The invention according to any one of claims 1 to 10 may be characterized in that, as in the invention according to claim 11, the rotating machine has a pole pair number of "5" or more.

  According to a twelfth aspect of the present invention, in the invention according to any one of the first to eleventh aspects, the rotating machine is used as an actuator for an electric power steering.

  A power steering actuator is desired to have a particularly quick response to a demand for an increase in q-axis current. In this regard, in the above invention, the responsiveness can be enhanced by providing the operation means.

(First embodiment)
Hereinafter, an embodiment in which a control device for a rotating machine according to the present invention is applied to a control device for a three-phase 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). The number of pole pairs of the electric motor 10 is “7” in the present embodiment.

  An inverter 12 is connected to the three phases (U phase, V phase, and W phase) of the electric motor 10. The inverter 12 is a three-phase inverter, and includes a parallel connection body of switching elements SW1 and SW2, switching elements SW3 and SW4, and switching elements SW5 and SW6 corresponding to the three phases. Further, the inverter 12 includes diodes D1 to D6 connected in antiparallel to the switching elements SW1 to SW6. And the connection point which connects switching element SW1 and switching element SW2 in series is connected with the U phase of the electric motor 10. FIG. Further, a connection point connecting the switching element SW3 and the switching element SW4 in series is connected to the V phase of the electric motor 10. Further, a connection point connecting the switching element SW5 and the switching element SW6 in series is connected to the W phase of the electric motor 10. Incidentally, these switching elements SW1 to SW6 are constituted by insulated gate bipolar transistors (IGBT) in this embodiment.

  The voltage of the battery 16 is applied to both ends of each set of switching elements SW1 and SW2, switching elements SW3 and SW4, and switching elements SW5 and SW6 of the inverter 12 via a smoothing capacitor.

  On the other hand, the microcomputer (microcomputer 20) takes in the detection results of the position sensor 22 that detects the rotation angle of the output shaft of the electric motor 10 and the current sensors 24 and 26 that detect the current flowing in the U phase and the V phase. The microcomputer 20 calculates the current flowing in the W phase from the current flowing in the U phase and the current flowing in the V phase based on Kirchhoff's law. Then, the microcomputer 20 operates the switching elements SW1 to SW6 via the gate drive circuit GD based on the rotation angle of the output shaft of the electric motor 10, the currents flowing through the three phases, and the like. Specifically, in the power steering, torque generated by a steering operation (not shown) is detected, and the microcomputer 20 calculates the required torque Td according to this. Further, the microcomputer 20 operates the switching elements SW1 to SW6 so that the output torque of the electric motor 10 becomes the required torque Td.

  FIG. 2 shows a functional block diagram of processing related to generation of an operation signal for operating the switching elements SW1 to SW6 among the processing performed by the microcomputer 20. In the present embodiment, since the actual current flowing through the electric motor 10 is controlled to become the command currents idc and iqc on the dq axis, various calculation parameter calculation processes on the dq axis are particularly shown. Therefore, an equivalent model on the dq axis is also illustrated for the electric motor 10 to be controlled.

In the present embodiment, using the voltage equation, the deviation of the actually output voltage from the command current idc, iqc and the actual current id, iq to the voltage to be output to the electric motor 10 to flow the command current idc, iqc. And the command voltages vdc1 and vqc1 are set so that this becomes zero. Here, the voltage equation of the electric motor 10 is expressed by the following equation using the resistance R, the d-axis inductance Ld, the q-axis inductance Lq, and the 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 formula, if the command currents idc and iqc are substituted in place of the actual currents id and iq, it is considered that the voltage to be output to the electric motor 10 to calculate the command currents idc and iqc is calculated. Therefore, the d-axis component of the deviation can be calculated by substituting the difference between the command current idc and the actual current id in the above formula (c1), and the command current in the above formula (c2). By substituting the difference between iqc and actual current iq, the q-axis component of the deviation can be calculated.

  That is, the d-axis deviation calculating unit 30 calculates the difference between the actual current id and the command current idc, and the q-axis deviation calculating unit 32 calculates the difference between the actual current iq and the command current iqc. Then, the d-axis non-interference term calculation unit 34 performs an operation related to the first term on the right side of the equation (c1) based on the output of the d-axis deviation calculation unit 30. On the other hand, the d-axis interference term calculation unit 36 performs a calculation related to the second term on the right side of the equation (c1) based on the output of the q-axis deviation calculation unit 32. Then, the d-axis voltage deviation calculation unit 38 calculates the d-axis voltage deviation ΔVd by subtracting the output of the d-axis interference term calculation unit 36 from the output of the d-axis non-interference term calculation unit 34.

  On the other hand, the q-axis non-interference term calculation unit 40 performs an operation related to the first term on the right side of the equation (c2) based on the output of the q-axis deviation calculation unit 32. On the other hand, the q-axis interference term calculation unit 42 performs an operation related to the second term on the right side of the equation (c2) based on the output of the d-axis deviation calculation unit 30. Then, the q-axis voltage deviation calculation unit 44 calculates the q-axis voltage deviation ΔVq by adding the output of the q-axis non-interference term calculation unit 40 and the output of the q-axis interference term calculation unit 42.

  The d-axis integration calculation unit 46 calculates the command voltage Vdc1 by integration calculation of the d-axis voltage deviation ΔVd using the integration gain Kω. On the other hand, the q-axis integration calculation unit 48 calculates the command voltage Vqc1 by integration calculation of the q-axis voltage deviation ΔVq using the integration gain Kω. The command voltages Vdc1 and Vqc1 are values for reducing the difference between the actual voltage and the voltage to be output to the electric motor 10 in order to flow the command currents idc and iqc.

  In the voltage limiting unit 50, when the vector lengths of the command voltages Vdc1 and Vqc1 exceed the limit voltage Vth, the vector lengths of the final command voltages Vdc and Vqc are limited by correcting the command voltages Vdc1 and Vqc1. The voltage is set to be equal to or lower than Vth. The final command voltages Vdc and Vqc are converted into UVW-phase command voltages in the PWM / inverter 52, and the inverter 12 shown in FIG. 1 is operated by PMW control. That is, the operation signals gup, gun, gvp, vn, gwp, and gwn calculated by PWM control so as to set the UVW phase command voltage as the output voltage are output to the gate drive circuit GD shown in FIG. The inverter 12 is operated.

  Hereinafter, the effect of setting the command voltages Vdc and Vqc according to the above aspect will be described.

  FIG. 3 illustrates how the command voltages Vdc and Vqc are set when the motor 10 is in the low rotation speed region and when the motor 10 is in the high rotation speed region.

  In this embodiment, since SPMSM is used as the electric motor 10, the output of the electric motor 10 can be controlled so that the required torque 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, the d-axis command current idc is basically set to zero in order to perform the maximum torque control. Therefore, in view of the fact that the rotational speed ω can be ignored in the low rotational speed region of the electric motor 10, the q-axis command voltage Vq can be approximated to “Riq”, and the d-axis command voltage Vq is substantially zero. . Therefore, the command voltages Vdc and Vqc vary on the q axis in accordance with the change in the q axis command current iqc.

  On the other hand, in the high rotation speed region of the electric motor 10, since the rotation speed ω is large, the second term on the right side of the above equations (c1) and (c2) is a large value. Therefore, the q-axis command voltage Vq can be approximated to “ωΦa”, and the d-axis command voltage can be approximated to “−ωLq × iq”. For this reason, when the command current iqc is increased to increase the required torque, it is necessary to advance the command voltage vector (Vdc, Vqc).

  Here, according to the above process, the command voltage vector (Vdc, Vqc) can be rapidly advanced. This is a voltage deviation vector (ΔVd, ΔVq), which is a deviation vector of the voltage actually output with respect to the voltage to be output to the motor 10 in order to flow the command currents idc, iqc. This is because when iqc increases, a request to increase the d-axis voltage to be output occurs. For this reason, for example, as illustrated in FIG. 4 when the length of the command voltage vector (Vdc, Vqc) becomes the limit voltage Vth, the voltage deviation vector (ΔVd, ΔVq) is equal to the command voltage vector (Vdc, Vqc). It is the direction to advance the phase. In other words, the direction approximates the tangential direction of the curve at the intersection of the curve determined by the limit voltage Vth and the command voltage vector (Vdc, Vqc). For this reason, the command voltage vectors (Vdc1, Vqc1) calculated by performing the integral operation of the voltage deviation vectors (ΔVd, ΔVq) do not increase greatly in length, and are advanced in phase. Become.

  Therefore, according to the above process, the phase of the command voltage vector (Vdc1, Vqc1) can be advanced rapidly. In calculating the q-axis voltage deviation ΔVq, the term of the back electromotive force in the voltage equation was simply deleted. This is because the phase of the command voltage vector (Vdc1, Vqc1) can be rapidly advanced according to the processing of the present embodiment, and therefore the influence of the change in the back electromotive force due to the change in the rotation speed of the motor 10 is This is because compensation is possible by integral control of the voltage deviation vector (ΔVd, ΔVq).

  However, when the length of the command voltage vector (Vdc1, Vqc1) exceeds the limit voltage Vth, the corrected command voltage vector (Vdc1, Vqc1) is used as the command voltage vector (Vdc, Vqc), and the integration calculation is limited. To do. Hereinafter, this will be described with reference to FIG. FIG. 5 shows processing performed by the voltage limiting unit 50 shown in FIG. This process is actually repeatedly executed by the microcomputer 20 at a predetermined cycle, for example.

  In this series of processing, first, in step S10, the voltage deviations ΔVd and ΔVq are calculated by the above-described processing based on the command currents idc and iqc and the actual currents id and iq. In a succeeding step S12, it is determined whether or not the limit over flag is on. The limit over flag is turned on when the length Vom (n−1) of the command voltage vector (Vdc1, Vqc1) calculated in the previous control cycle exceeds the limit voltage Vth. This process is for determining whether or not to limit the integral operation.

  Here, the limit voltage Vth is obtained by multiplying a value “√ (3/8)” times the voltage VB of the battery 16 by a predetermined value A. Here, it is desirable that the predetermined value A is, for example, a value of about “1.05 to 1.10”. In other words, if the length of the command voltage vector is greater than or equal to “√ (3/8)” times the voltage VB of the battery 16, the output voltage of the inverter 12 cannot be used as the command voltage. For this reason, the limit voltage Vth is normally set to a value not more than “√ (3/8)” times the voltage VB of the battery 16. However, in the present embodiment, when the length of the command voltage vector is in the vicinity of a value “√ (3/8)” times the voltage VB of the battery 16, the command voltage vector is calculated so that the phase advances by the integration calculation. It is not calculated so that the length becomes excessively large. At this time, if the integral calculation is prohibited when the voltage VB of the battery 16 is a value less than “√ (3/8)” times, the phase of the command voltage vector is rapidly advanced by the integral calculation. There is a concern that it will be an obstacle. For this reason, the limit voltage Vth is set to a value larger than “√ (3/8)” times the voltage VB of the battery 16.

  If it is determined in step S12 that the limit over flag is on, in steps S14 to S24, processing for limiting the integral calculation is performed. That is, in step S14, it is determined whether or not the product of the current voltage deviation ΔVd and the previous command voltage Vdc1 (n−1) is negative. That is, it is determined whether or not the integral calculation value (command voltage Vdc1) of the d-axis is increased by the integral calculation. This process determines whether or not the d-axis integral calculation need not be restricted. If an affirmative determination is made in step S14, it is determined that there is no need to limit the d-axis integral calculation, and the process proceeds to step S16. In step S16, the current d-axis command voltage Vdc1 (n) is calculated by integration. That is, Vdc1 (n) is calculated by multiplying the previous command voltage Vdc1 (n−1) by an amount corresponding to the voltage deviation ΔVd. On the other hand, when a negative determination is made in step S14, the current command voltage Vdc1 (n) is set to the previous command voltage Vdc1 (n-1) in step S18.

  When the processes of steps S16 and S18 are completed, the process proceeds to step S20. In step S20, it is determined whether or not the product of the previous command voltage Vqc1 (n-1) and the current voltage deviation ΔVq is negative. That is, it is determined whether or not the integral calculation value (command voltage Vqc1) of the q axis is increased by the integral calculation. This process determines whether or not the q-axis integral calculation need not be limited. If an affirmative determination is made in step S20, it is determined that the q-axis integration calculation need not be restricted, and the process proceeds to step S22. In step S22, the current q-axis command voltage Vqc1 (n) is calculated by integration. That is, the command voltage Vqc1 (n) is calculated by multiplying the previous command voltage Vqc1 (n-1) by an amount corresponding to the voltage deviation ΔVq. On the other hand, when a negative determination is made in step S20, the current command voltage Vqc1 (n) is set to the previous command voltage Vqc1 (n-1) in step S22.

  On the other hand, when a negative determination is made in step S12, command voltages Vdc (n) and Vqc (n) are calculated by a normal integration operation in step S26. Then, when the processes of steps S22, S24, and S26 are completed, the process proceeds to step S28.

  In step S28, the length of the current command voltage vector (Vdc1, Vqc1) is calculated. In the following step S30, it is determined whether or not the length of the command voltage vector (Vdc1, Vqc1) is larger than the limit voltage Vth. When it is determined that the voltage is higher than the limit voltage Vth, the final command voltage vector (Vdc, Vqc) is calculated by correcting the command voltage vector (Vdc1, Vqc1) in step S32. That is, the length of the vector is changed by multiplying the command voltage vector (Vdc1, Vqc1) by the ratio of the limit voltage Vth to the length Vom. At this time, the restriction over flag is turned on. On the other hand, when a negative determination is made in step S30, the current command voltage vector (Vdc, Vqc) is set as the current command voltage vector (Vdc1, Vqc1) in step S34. At this time, the restriction over flag is turned off.

  When the processes in steps S32 and S34 are completed, this series of processes is temporarily terminated.

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

  (1) Based on the command currents idc, iqc and the actual currents id, iq, the actual voltage deviation (voltage deviations ΔVd, ΔVq) with respect to the voltage on the dq axis to be output to the electric motor 10 to flow the command currents idc, iqc ) Was calculated, and the output voltage for the inverter 12 was manipulated to reduce it. As a result, the phase of the output voltage vector can be rapidly advanced, and the response of output control can be improved.

  (2) The voltage deviations ΔVd and ΔVq were calculated based on a voltage equation for converting a current on the dq axis into a voltage on the dq axis. Thereby, the voltage deviations ΔVd and ΔVq can be appropriately calculated.

  (3) The command voltages Vdc1 and Vqc1 were calculated by integrating the voltage deviations ΔVd and ΔVq. Thus, the command voltages Vdc1 and Vqc1 can be set so that the voltage deviations ΔVd and ΔVq are always zero in the steady state.

  (4) When the length of the command voltage vector (Vdc1, Vqc1) exceeds the limit voltage Vth, the calculation of the integral calculation is limited. Thereby, it can be avoided that the length of the command voltage vector (Vdc1, Vqc1) becomes excessively large.

  (5) When the length of the command voltage vector (Vdc1, Vqc1) exceeds the limit voltage Vth, the calculation of the increasing direction of the absolute values of the d-axis and q-axis command voltages Vdc1, Vqc1 is prohibited. Thereby, it can avoid that an integral calculation value becomes large too much.

  (6) The number of pole pairs of the electric motor 10 is set to “7”. As described above, in an electric motor having a large number of pole pairs, the rotational speed tends to increase easily, and thus the above-described effects can be achieved particularly suitably.

  (7) The electric motor 10 was used as an actuator for electric power steering. Since the power steering actuator is desired to have a particularly quick response to a request for increasing the q-axis current, the above-described effects can be achieved particularly suitably.

(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 a procedure of processing performed by the voltage limiting unit 50 according to the present embodiment. This process is actually repeatedly executed by the microcomputer 20 at a predetermined cycle, for example.

  In this series of processing, first, in step S40, the voltage deviations ΔVd and ΔVq are calculated in the same manner as in step S10 of FIG. In the following step S42, command voltages Vdc1 (n) and Vqc1 (n) are calculated based on the integral calculation of the voltage deviations ΔVd and ΔVq. Further, in step S44, the length Vom (n) of the command voltage vector (Vdc1, Vqc1) is calculated in the same manner as in step S28 of FIG. In the subsequent step S46, it is determined whether or not the length Vom (n) exceeds the limit voltage Vth, as in step S30 of FIG. If it is determined that the voltage exceeds the limit voltage Vth, the same processing as in step S32 of FIG. 5 is performed in step S48. If it is determined that the voltage is less than or equal to the limit voltage Vth, the process proceeds to step S52. The same process as step S34 in FIG.

  When the process of step S48 is completed, in this embodiment, the current command voltages Vdc1 (n) and Vqc (n) are set as the command voltages Vdc and Vqc subjected to the process of step S48. Thereby, it can avoid that an integral calculation value becomes excessive. In particular, in this embodiment, unlike the first embodiment, the IF statement is not used for the process for limiting the integral calculation value, so that the calculation load of the microcomputer 20 can be reduced.

  FIG. 7 shows the responsiveness of the above processing when the required torque is increased stepwise in the high rotational speed region. Specifically, in FIG. 7 (a), the change of the modulation factor when the voltage VB of the battery 16 is "35V" is shown by a thick line, and the case where the voltage VB is "30V" by a one-dot chain line. Shows the transition of the modulation rate. In FIG. 7 (b), the thick line shows the transition of the voltage phase when the voltage VB of the battery 16 is set to “35V”, and the voltage when the voltage VB is set to “30V” by the one-dot chain line. The phase transition is shown. Further, in FIG. 7C, the bold axis shows the transition of the q-axis actual current when the voltage VB of the battery 16 is set to “35V”, and the same voltage VB is set to “30V” by the one-dot chain line. Of the q-axis actual current, and the transition of the q-axis command current iqc is indicated by a two-dot chain line. As shown in the figure, although the modulation rate increases as the voltage VB of the battery 16 is lower, there is no great difference in the response.

  On the other hand, when the required torque is increased stepwise in the high rotation speed region in the case where the integration calculation units 46 and 48 of FIG. 2 are arranged immediately after the deviation calculation units 30 and 32 in FIG. Shows the responsiveness. 8A to 8C correspond to FIGS. 7A to 7C. As shown in the figure, the responsiveness decreases due to the fact that the modulation rate increases as the voltage VB of the battery 16 decreases. That is, as shown in FIG. 9, when the length of the voltage vector is in the vicinity of a value “√ (3/8)” times the voltage VB of the battery 16, the responsiveness of the voltage vector is lowered. This is because the integration calculation is stopped because the command voltage vector is calculated in the direction in which the length of the command voltage vector extends when the value of the current deviation is substituted into the voltage equation. For this reason, responsiveness falls in the high rotation speed area | region shown in FIG.

According to this embodiment described above, in addition to the effects (1) to (4), (6), and (7) of the first embodiment, the following effects can be obtained. .
(8) When the length of the command voltage vector (Vdc1, Vqc1) exceeds the limit voltage Vth, the command voltage (Vdc1, Vqc1) is corrected so that the length of the vector is equal to or less than the limit voltage Vth. Thereby, it can be avoided that the integral calculation value becomes an excessively inappropriate value.

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

  FIG. 11 is a functional block diagram of processing related to generation of an operation signal for operating the switching elements SW1 to SW6 according to the present embodiment. In FIG. 11, processes corresponding to those in FIG. 2 are given the same reference numerals for convenience.

  As shown in the figure, in the present embodiment, the actual output voltage of the inverter 12 is estimated according to the actual currents id and iq, and the values of the integral calculation units 46 and 48 are corrected based on this. That is, the d-axis non-interference term calculation unit 60 performs a calculation related to the first term on the right side of the equation (c1) based on the actual current id. On the other hand, the d-axis interference term calculation unit 62 performs an operation related to the second term on the right side of the equation (c1) based on the actual current iq. The d-axis voltage calculation unit 64 calculates the d-axis voltage Vd by subtracting the output of the d-axis interference term calculation unit 62 from the output of the d-axis non-interference term calculation unit 60. Further, the proportional term calculation unit 66 multiplies the d-axis voltage Vd by a proportional gain Kp. Then, the d-axis command voltage correction unit 68 corrects the command voltage Vdc1 that is the output of the integral calculation unit 46 by subtracting the output of the proportional term calculation unit 66 from the output of the integration calculation unit 46, and the voltage limiting unit 50. Output to.

  On the other hand, the q-axis non-interference term calculation unit 70 performs an operation on the first term on the right side of the above formula (c2) based on the actual current iq. On the other hand, the q-axis interference term calculation unit 72 performs a calculation related to the second term on the right side of the above formula (c2) based on the actual current id (however, the term of the back electromotive voltage is simply excluded). Then, the q-axis voltage calculation unit 74 calculates the q-axis voltage Vq by adding the output of the q-axis non-interference term calculation unit 70 and the output of the q-axis interference term calculation unit 72. Further, the proportional term calculation unit 76 multiplies the q-axis voltage Vq by a proportional gain Kp. Then, the q-axis command voltage correction unit 78 corrects the command voltage Vqc1 that is the output of the integral calculation unit 48 by subtracting the output of the proportional term calculation unit 76 from the output of the integration calculation unit 48, and the voltage limiting unit 50. Output to. The voltage limiting unit 50 performs the processing shown in the first embodiment based on the corrected command voltages Vdc1 and Vqc1.

According to such processing, the degree of freedom in design can be increased by providing the proportional gain Kp.
(9) The actual output voltages Vd and Vq on the dq axis are calculated based on the actual currents id and iq on the dq axis, and the command voltages Vdc1 and Vqc1 are corrected accordingly. Thereby, the freedom degree of control, such as a gain setting, can be improved.

(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 is a functional block diagram of processing relating to generation of an operation signal for operating the switching elements SW1 to SW6 according to the present embodiment. In FIG. 12, the same reference numerals are assigned for convenience to the processes corresponding to those in FIG.

  As shown in the drawing, in the present embodiment, the actual currents id and iq are filtered by the low-pass filters 92 and 94 and then used by the deviation calculation units 30 and 32, for example. This is because high-frequency noise is more likely to be mixed into the actual currents id and iq than the rotation period of the electrical angle of the electric motor 10. Further, in the present embodiment, the command currents idc and iqc are also subjected to filter processing by the low-pass filters 96 and 98. These low-pass filters 90 to 98 have the same characteristics. As a result, the delay amounts of the actual currents id and iq and the delay amounts of the command currents idc and iqc can be made the same.

  In the present embodiment, first-order lag filters are used as the low-pass filters 90 to 98, and their time constants and the like are set to be the same.

  According to the present embodiment described above, the following effects can be obtained in addition to the effects of the third embodiment.

  (10) Both the command currents idc and iqc and the actual currents id and iq were subjected to filter processing using low-pass filters 90 to 96 having the same characteristics. As a result, the delay amounts of the command currents idc and iqc and the actual currents id and iq can be made the same, so that the voltage deviations ΔVd and ΔVq, the output voltages Vdc and Vqc, and the like can be calculated with higher accuracy. .

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

  FIG. 13 is a functional block diagram of processing related to generation of an operation signal for operating the switching elements SW1 to SW6 according to the present embodiment. In FIG. 13, the processes corresponding to those in FIG. 2 are given the same reference numerals for the sake of convenience.

  In the present embodiment, the command voltages Vdc, Vqc are converted into UVW phase command voltages Vuc, Vvc, Vwc by an angle advanced by an advance amount Δθ with respect to the current rotation angle θ (electrical angle). Based on the above, the output voltage of the inverter 12 is manipulated.

  FIG. 14 shows a procedure for converting the command voltages Vdc, Vqc to the UVW phase command voltages Vuc, Vvc, Vwc according to the present embodiment. This process is repeatedly executed by the microcomputer 20 at a predetermined cycle, for example.

  In this series of processing, first, in step S70, the rotation angle θ and the rotation speed ω are detected. In the following step S72, the rotation amount (advance amount Δθ) of the electric motor 10 within the time T from the detection timing of the rotation angle θ to the operation timing of the output voltage of the inverter 12 corresponding to the command voltages Vuc, Vvc, Vwc is calculated. calculate. This can be calculated by multiplying the rotational speed ω by the time T.

  In subsequent step S74, the command voltages Vdc and Vqc are set to the UVW phase command voltage at an angle “θ + Δθ” obtained by adding the advance amount Δθ calculated in step S72 to the rotation angle θ detected in step S70. Convert to Vuc, Vvc, Vwc. In step S76, the operation signals gup, gun, gvp, gvn, gwp, gwn of the switching elements SW1 to SW6 are generated according to the UVW phase command voltages Vuc, Vvc, Vwc. Here, for example, the operation signals gup, gun, gvp, gvn, gwp, and gwn may be generated by triangular wave PWM processing of the UVW phase command voltages Vuc, Vvc, and Vwc. When the process of step S76 is completed, this series of processes is temporarily ended.

  According to the above processing, it is possible to calculate the command voltages Vuc, Vvc, Vwc appropriate for the rotation angle at the timing when the output voltage of the inverter 12 is operated. For this reason, the error of the rotation angle resulting from the time lag from the detection timing of the rotation angle θ to the operation timing of the output voltage of the inverter 12 can be suitably compensated.

  According to this embodiment described above, in addition to the effects (1) to (7) of the first embodiment, the following effects can be obtained.

  (11) Based on the angle obtained by advancing the rotation angle θ by the advance amount Δθ, the command voltages Vdc, Vqc are converted into UVW phase command voltages Vuc, Vvc, Vwc. Thereby, the output voltage can be made more appropriate according to the rotation angle.

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

  The calculation method of the command voltages Vdc1 and Vqc1 is not limited to the integral calculation of the voltage deviations ΔVd and ΔVq. For example, proportional integral calculation or proportional integral differential calculation of the voltage deviations ΔVd and ΔVq may be used. Further, it may be a proportional calculation of the voltage deviations ΔVd and ΔVq or a differential calculation of the voltage deviations ΔVd and ΔVq.

  The changes in the second embodiment from the first embodiment may be applied to the third to fifth embodiments.

  A change in the third embodiment from the first embodiment may be applied to the second and fifth embodiments.

  A change in the fourth embodiment from the third embodiment may be applied to the first, second, and fifth embodiments.

  -The change in 5th Embodiment from 1st Embodiment may be applied to 2nd-4th Embodiment.

  In the third and fourth embodiments, instead of adding the proportional gain Kp to the calculated voltages Vd and Vq, a proportional integration calculation and a proportional integration differential calculation of the calculated voltages Vd and Vq may be performed.

  In the fourth embodiment, the low-pass filters 92 to 98 are not limited to the first-order lag filter, but may be, for example, a second-order lag filter.

  In calculating the q-axis voltage deviation ΔVq, the term of the back electromotive force in the voltage equation may be taken into consideration.

  The method for setting the limit voltage Vth is not limited to that exemplified in the above embodiment. Here, the predetermined value A is desirably “1” or more, and more desirably greater than “1”.

  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. Further, the number of pole pairs is not limited to “7”. For example, it may be “5” or more. However, since the electrical angular frequency tends to increase as the number of pole pairs increases, the voltage vector needs to be manipulated so that the phase advances in the vicinity of the modulation rate of “1”. it can.

  -The rotating machine is not limited to an electric motor but may be a generator.

The figure which shows the whole structure of the control system of the electric motor concerning 1st Embodiment. The block diagram which shows the process regarding calculation of the operation signal of the inverter concerning the embodiment. The figure which shows the setting aspect of the command voltage of a high rotational speed area | region and a low rotational speed area | region. The figure which shows the voltage deviation vector and command voltage vector concerning the said embodiment. The flowchart which shows the procedure of the calculation process of the command voltage concerning the embodiment. The flowchart which shows the procedure of the calculation process of the command voltage concerning 2nd Embodiment. The time chart which shows the responsiveness of the phase of the voltage vector and q-axis current concerning the embodiment. The time chart which shows the responsiveness of the phase of a voltage vector by a prior art, and q-axis current. The figure which shows the example of a transition of the voltage vector by the said prior art. The figure which shows the responsiveness fall area | region by the said prior art. The block diagram which shows the process regarding calculation of the operation signal of the inverter concerning 3rd Embodiment. The block diagram which shows the process regarding calculation of the operation signal of the inverter concerning 4th Embodiment. The block diagram which shows the process regarding calculation of the operation signal of the inverter concerning 5th Embodiment. The flowchart which shows the procedure of the three-phase conversion process of the command voltage concerning the embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Electric motor, 12 ... Inverter, 20 ... Microcomputer (one Embodiment of a control apparatus).

Claims (12)

In the control device for a rotating machine that controls the rotation state of the rotating machine by manipulating the output voltage of the inverter with respect to the rotating machine,
Based on the d-axis and q-axis command currents of the rotating machine and the actual currents of the d-axis and the q-axis, the actual voltage with respect to the voltage on the dq-axis to be output to the rotating machine in order to flow the command current Voltage deviation calculating means for calculating the deviation of
An operation device for operating the output voltage so as to reduce the calculated deviation.   2. The control device for a rotating machine according to claim 1, wherein the voltage deviation calculating unit calculates the voltage deviation based on a voltage equation for converting the current on the dq axis into a voltage on the dq axis.   The operation means includes command voltage calculation means for calculating a command voltage for the inverter based on a plurality of values that are chronologically related to the calculated deviation, and operates the output voltage of the inverter based on the command voltage. The control device for a rotating machine according to claim 1, wherein:   4. The rotating machine according to claim 3, wherein the command voltage calculation means includes means for calculating a cumulative value of the calculated voltage deviation and means for calculating the command voltage based on the cumulative value. Control device.   The command voltage calculating means is means for calculating an actual output voltage on the dq axis based on an actual current on the dq axis, and means for correcting the command voltage in accordance with the calculated actual output voltage. The rotating machine control device according to claim 4, further comprising:   6. The rotating machine according to claim 4, further comprising a limiting unit that limits calculation of the cumulative value when a length of a vector of the command voltage calculated by the command voltage calculating unit exceeds a limit voltage. Control device.   The restriction means prohibits the calculation of the increasing direction of the absolute value of the d-axis component and the q-axis component of the cumulative value when the length of the command voltage vector calculated by the command voltage calculation means exceeds the limit voltage. The rotating machine control device according to claim 6, further comprising: means.   The limiting means corrects the command voltage so that the length of the vector becomes equal to or less than the limit voltage when the length of the vector of the command voltage calculated by the command voltage calculation means exceeds the limit voltage; 7. The rotating machine control device according to claim 6, further comprising means for forcibly changing the cumulative value in accordance with the corrected command voltage.   9. The input of the command current and the actual current to the voltage deviation calculating means is performed by performing a filtering process with a low-pass filter having the same characteristics on both of them. Control device for rotating machine. Means for obtaining a rotation angle and a rotation speed of the rotating machine;
The operation means includes command voltage calculation means for calculating a command voltage on the dq axis so as to reduce the deviation of the calculated voltage, and from the timing of obtaining the rotation angle to the timing of updating the output voltage of the inverter. Means for calculating the amount of rotation of the rotating machine at the time of time based on the acquired rotation speed, and a command on the dq axis based on an angle advanced by the amount of rotation with respect to the acquired rotation angle 10. A rotating machine according to claim 1, further comprising means for converting a voltage into a command voltage for each phase of the inverter, and operating the output voltage based on the command voltage for each phase. Control device.   The control device for a rotating machine according to claim 1, wherein the rotating machine has a pole pair number of “5” or more.   The control device for a rotating machine according to claim 1, wherein the rotating machine is used as an actuator for an electric power steering.

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