JP5659971B2 - Rotating machine control device - Google Patents

Description

  The present invention relates to a power conversion circuit including a switching element that opens and closes between a voltage applying unit having a plurality of different voltage values and a terminal of a rotating machine. The present invention relates to a control device for a rotating machine that controls a control amount having at least one of a current flowing through the rotating machine, a torque of the rotating machine, and a magnetic flux of the rotating machine by an on / off operation.

  As this type of control device, an operation state that can predict the current of the three-phase motor when the operation state of the inverter is set variously, and minimize the deviation between the predicted current and the command current, Thus, what performs so-called model predictive control for operating an inverter has been proposed.

  By the way, according to the model predictive control, since the values of the predicted current and the command current are to be minimized, the switching frequency of the switching state may be increased.

  Therefore, conventionally, as can be seen, for example, in Patent Document 1 below, when the absolute value of the difference between the predicted current and the command current when the current operation state is maintained is within a predetermined range, the current operation state is maintained. Has also been proposed.

JP 2011-50121 A

  However, in the case of the above technique, when the operation state when the state is shifted to within the predetermined range is an operation state in which the current of the rotating machine is rapidly changed, the period of staying within the predetermined range is shortened. Switching is not necessarily limited appropriately.

  The present invention has been made in the process of solving the above-mentioned problems, and its object is to include a switching element that opens and closes between a voltage applying means having a plurality of different voltage values and a terminal of the rotating machine. And a control having at least one of a current flowing through the rotating machine, a torque of the rotating machine, and a magnetic flux of the rotating machine by an on / off operation of a switching element constituting the power converting circuit. An object of the present invention is to provide a new control device for a rotating machine that controls the amount.

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

A first invention relates to a power conversion circuit configured to include a switching element that opens and closes between a voltage applying unit having a plurality of different voltage values and a terminal of a rotating machine, and the switching that configures the power conversion circuit In the control device for a rotating machine that controls a control amount having at least one of an electric current flowing through the rotating machine, a torque of the rotating machine, and a magnetic flux of the rotating machine by an on / off operation of an element. A control amount prediction means for temporarily setting an operation state of the power conversion circuit expressed by a voltage vector determined by an operation, and predicting the control amount realized by the temporarily set operation state; and The absolute value of the difference between the predicted control amount and its command value when the operation state is temporarily set to the same operation state as the current operation state is equal to or less than a specified value. The operation state of the power conversion circuit represented by a voltage vector determined by the on / off operation is temporarily set, and the temporary setting is performed. Relative speed prediction means for predicting the relative speed with respect to the command value for the control amount corresponding to each of the operated states, and the difference between the actual control amount and the command value exceeds the specified value and the specified value Predicted by the relative speed prediction means among those that do not increase the absolute value of the difference between the control amount and the command value in a situation that enters from outside the relative speed evaluation area that is an area that is less than or equal to a threshold value greater than the value. On the condition that the operation state corresponding to the small absolute value of the relative speed is different from the current operation state, the operation state corresponding to the small absolute value of the relative speed Characterized in that it comprises a changing means for changing the.

  According to the limiting means, if the absolute value of the difference between the predicted control amount and its command value is less than or equal to the specified value, the current operation state tends to be maintained, but less than the specified value. When the operation state employed when the absolute value of the relative speed is increased, the time during which the absolute value of the difference between the control amount and the command value remains below the specified value is shortened. In this regard, in the above-described invention, a relative speed evaluation area is provided, and in this area, by changing to an operation state in which the absolute value of the relative speed is small, the time remaining in the area that is equal to or less than the specified value can be made as long as possible.

According to a second invention, in the first invention, the changing means determines that the absolute value of the difference is the threshold value by comparing the difference between the predicted control amount and its command value with the threshold value and the specified value. Area determination means for determining whether or not the difference between the predicted control amount and the command value is within the relative speed evaluation area by determining whether or not it is equal to or less than a specified value. And determining that it is in the situation on condition that it is determined to be within the area by the area determining means.

  When it is determined that the absolute value of the difference between the predicted control amount and its command value is less than the threshold value and greater than the specified value, the absolute value of the difference between the actual control amount and its command value is also the threshold value. It may be less than or equal to the specified value. In particular, when the above determination is made a plurality of times, there is a high probability that the absolute value of the difference between the actual control amount and the command value is not more than a threshold value and not less than a specified value. In view of this point, the above invention includes an area determination unit.

A third invention is characterized in that, in the second invention, the specified value is set separately for each of a zero voltage vector and an effective voltage vector among voltage vectors representing an operation state of the power conversion circuit.

  The change rate of the control amount can be different between the case where the zero voltage vector is used and the case where the effective voltage vector is used. In the above-mentioned invention, in view of this point, it is possible to set a prescribed value corresponding to the change rate of the controlled variable by setting the prescribed values separately for the zero voltage vector and the effective voltage vector.

A fourth invention is characterized in that, in the third invention, the specified value is variable in accordance with time in a mode that can be a value smaller than the threshold value.

  The inventors have found that when the prescribed value is fixed, a steady divergence is likely to occur between the controlled variable and its command value. In view of this point, the above invention makes it possible to suppress the occurrence of a steady divergence tendency by making the specified value variable.

In a fifth aspect based on the first aspect , the changing means is such that the difference between the actual control amount and its command value is less than or equal to the threshold value among the changeable timings of the operation state. It is characterized by further comprising a transition determination means for determining that the situation is present only after a predetermined number of times closest to the transition timing, which is a timing after the transition to the state.

  In the above invention, when not much time has passed since the transition from the state above the threshold to the state below the threshold, the absolute value of the difference between the control amount and the command value remains in the region above the specified value. Probability is high. In view of this point, the above invention provides a shift determination means.

A sixth invention is characterized in that, in any one of the first to fifth inventions, the relative speed prediction means substitutes a change speed of the control amount as the relative speed.

  In a steady state where the command value of the control amount does not change, the change rate of the control amount and the relative speed of the control amount with respect to the command value are in a proportional relationship at least with respect to their absolute values. In view of this point, the above invention predicts the change rate of the control amount.

In a seventh aspect based on any one of the first to sixth aspects, the power conversion circuit includes a switching element that selectively connects a terminal of the rotating machine to each of a positive electrode and a negative electrode of a DC voltage source. It is a DC / AC converter circuit.

1 is a system configuration diagram according to a first embodiment. FIG. The figure which shows the voltage vector expressing the operation state of an inverter. The flowchart which shows the procedure of the model prediction process concerning the said embodiment. The figure which shows the operation state used as the temporary setting candidate concerning the embodiment. The time chart which shows the change process of the operation state concerning the embodiment. The flowchart which shows the procedure of the change process of the regulation value concerning the embodiment. The figure which shows the effect concerning the embodiment. The flowchart which shows the procedure of the model prediction process concerning 2nd Embodiment. The system block diagram concerning 3rd Embodiment.

<First Embodiment>
Hereinafter, a first embodiment in which a control device for a rotating machine according to the present invention is applied to a control device for a hybrid vehicle will be described with reference to the drawings.

  FIG. 1 shows the overall configuration of a motor generator control system according to this embodiment. The motor generator 10 as an in-vehicle main machine is a three-phase permanent magnet synchronous motor. The motor generator 10 is a rotating machine (saliency pole machine) having saliency. Specifically, the motor generator 10 is an embedded magnet synchronous motor (IPMSM).

  The motor generator 10 is connected to the high voltage battery 12 via the inverter IV. The inverter IV includes three sets of series connection bodies of switching elements S * p, S * n (* = u, v, w), and the connection points of these series connection bodies are U, V, Each is connected to the W phase. In the present embodiment, insulated gate bipolar transistors (IGBTs) are used as the switching elements S * # (* = u, v, w; # = p, n). In addition, a diode D * # is connected in antiparallel to each of these.

  In this embodiment, the following is provided as detection means for detecting the state of the motor generator 10 and the inverter IV. First, a rotation angle sensor 14 for detecting the rotation angle (electrical angle θ) of the motor generator 10 is provided. Further, a current sensor 16 that detects currents iu, iv, and iw flowing through the phases of the motor generator 10 is provided. Further, a voltage sensor 18 for detecting an input voltage (power supply voltage VDC) of the inverter IV is provided.

  The detection values of the various sensors are taken into the control device 20 constituting the low voltage system via an interface (not shown). The control device 20 generates and outputs an operation signal for operating the inverter IV based on the detection values of these various sensors. Here, the signal for operating the switching element S * # of the inverter IV is the operation signal g * #.

  The control device 20 operates the inverter IV to control the torque of the motor generator 10 to the required torque Tr. Specifically, inverter IV is operated so that the command current for realizing required torque Tr matches the current flowing through motor generator 10. That is, in the present embodiment, the torque of the motor generator 10 becomes the final control amount. In order to control the torque, the current flowing through the motor generator 10 is directly controlled as a control current. To do. In particular, in the present embodiment, in order to control the current flowing through the motor generator 10 to a command current, the current of the motor generator 10 is predicted and predicted when the operation state of the inverter IV is temporarily set to each of a plurality of types. The temporarily set operation state is evaluated based on the current. Then, model predictive control is performed in which the highly evaluated one is adopted as the actual operation state of the inverter IV.

  Specifically, the phase currents iu, iv, iw detected by the current sensor 16 are converted into actual currents id, iq in the rotating coordinate system by the dq converter 22. Further, the electrical angle θ detected by the rotation angle sensor 14 is input to the speed calculation unit 23, and thereby the rotation speed (electrical angular speed ω) is calculated. On the other hand, the command current setting unit 24 receives the required torque Tr and outputs command currents idr and iqr in the dq coordinate system. The command currents idr and iqr, the actual currents id and iq, and the electrical angle θ are input to the model prediction control unit 30. Based on these input parameters, the model prediction control unit 30 determines a voltage vector Vi that defines the operation state of the inverter IV and inputs the voltage vector Vi to the operation unit 26. The operation unit 26 generates the operation signal g * # based on the input voltage vector Vi and outputs it to the inverter IV.

  Here, the voltage vectors expressing the operation state of the inverter IV are eight voltage vectors shown in FIG. For example, a voltage vector representing an operation state (indicated as “lower” in the drawing) in which the low-potential side switching elements Sun, Svn, Swn are turned on is the voltage vector V0, and the high-potential side switching elements Sup, A voltage vector representing an operation state (indicated as “upper” in the drawing) in which Svp and Swp are turned on is a voltage vector V7. These voltage vectors V0 and V7 are for short-circuiting all phases of the motor generator 10 and are called zero voltage vectors because the voltage applied to the motor generator 10 from the inverter IV becomes zero. On the other hand, the remaining six voltage vectors V1 to V6 are defined by an operation pattern in which switching elements that are turned on exist in both the upper arm and the lower arm, and are called effective voltage vectors. Yes. As shown in FIG. 2B, each of the voltage vectors V1, V3, and V5 corresponds to the positive side of the U phase, the V phase, and the W phase, respectively.

  Next, details of the processing of the model prediction control unit 30 will be described. In the operation state setting unit 31 shown in FIG. 1, the operation state of the inverter IV is set. Here, voltage vectors V0 to V7 shown in FIG. 2 are set as the operation state of inverter IV. The dq conversion unit 32 calculates the voltage vector Vdq = (vd, vq) in the dq coordinate system by performing dq conversion on the voltage vector set by the operation state setting unit 31. In order to perform such conversion, the voltage vectors V0 to V7 in the operation state setting unit 31 are, for example, “upper” as “VDC / 2” and “lower” as “−VDC / 2” in FIG. It can be expressed as above. In this case, for example, the voltage vector V0 is (−VDC / 2, −VDC / 2, −VDC / 2), and the voltage vector V1 is (VDC / 2, −VDC / 2, −VDC / 2). .

In the prediction unit 33, the current id when the operation state of the inverter IV is set to the state set by the operation state setting unit 31 based on the voltage vector (vd, vq), the actual currents id, iq, and the electrical angular velocity ω. , Iq is predicted. Here, the voltage equation expressed by the following (c1) and (c2) is discretized from the following state equations (formulas (c3) and (c4)) obtained by solving the current differential term. Predict.
vd = (R + pLd) id−ωLqiq (c1)
vq = ωLdid + (R + pLq) iq + ωφ (c2)
pid
= − (R / Ld) id + ω (Lq / Ld) iq + vd / Ld (c3)
piq
= −ω (Ld / Lq) id− (Rd / Lq) iq + vq / Lq−ωφ / Lq (c4)
Incidentally, in the above formulas (c1) and (c2), the resistance R, the differential operator p, the d-axis inductance Ld, the q-axis inductance Lq, and the armature flux linkage constant φ are used.

  The prediction of the current is performed for each of a plurality of operation states temporarily set by the operation state setting unit 31.

  On the other hand, the operation state determination unit 34 receives the predicted currents ide and iq predicted by the prediction unit 33 and the command currents idr and iqr, and determines the operation state of the inverter IV. Based on the operation state thus determined, the operation unit 26 generates and outputs an operation signal g * #.

  FIG. 3 shows a model prediction control processing procedure according to the present embodiment. This process is repeatedly executed at a predetermined cycle (control cycle Tc).

  In this series of processing, first, in step S10, the voltage vector V (n + 1) representing the operation state at the next update timing of the operation state of the inverter IV is changed to the voltage vector V (n) adopted at the current update timing. Temporarily set the operation state expressed as

  In subsequent step S12, predicted currents ide (n + 2) and iqe (n + 2) after one control cycle Tc are calculated by adopting voltage vector V (n + 1) at the next update timing. As a method for calculating the predicted currents ide (n + 2) and iqe (n + 2), for example, as described in the specification of Japanese Patent Application No. 2009-096443, the current value is predicted at the next update timing. A method using currents ide (n + 1) and iqe (n + 1) may be employed. Here, the predicted currents ide (n + 1) and iqe (n + 1) may be predicted using the actual currents id (n) and iq (n) detected at the current update timing as initial values.

  In the subsequent step S14, it is determined whether or not the voltage vector V (n + 1) representing the temporarily set operation state is a zero voltage vector. If an affirmative determination is made in step S14, the norm (error edq (n + 2)) of the vector difference between the predicted currents ide (n + 2) and iqe (n + 2) and the command currents idr and iqr is determined in step S16. It is determined whether or not the threshold value eth is equal to or smaller than a coefficient α (a value obtained by multiplying 0 <α <1). Here, “α · eth” is a parameter that defines a region in which change of the operation state is prohibited when the voltage vector representing the operation state adopted is a zero voltage vector.

  Here, the threshold value eth is variably set according to the required torque Tr, the electrical angular velocity ω, and the power supply voltage VDC. That is, as the required torque Tr is larger, the command currents idr and iqr are larger. Therefore, even if the difference is the same, the ratio of error to the command currents idr and iqr is smaller. For this reason, it is judged whether the ratio of the error with respect to the command currents idr and iqr is excessively large by setting the threshold value eth to a larger value as the required torque Tr is larger. Further, in view of the fact that the electric current is more likely to change as the electrical angular velocity ω is smaller, the threshold eth is set to a larger value as the electrical angular velocity ω is smaller, thereby preventing a situation exceeding “α · eth” from occurring. Furthermore, in view of the fact that the current is likely to change as the power supply voltage VDC increases, the threshold eth is set to a larger value as the power supply voltage VDC is increased, thereby preventing a situation exceeding “α · eth” from occurring.

  On the other hand, when a negative determination is made in step S14, it is determined in step S18 whether or not the error edq (n + 2) is equal to or less than a specified value (a value obtained by multiplying the threshold eth by a coefficient β (0 <β <1)). . Here, “β · eth” is a parameter that defines a region in which the change of the operation state is prohibited when the voltage vector representing the operation state adopted is an effective voltage vector.

  In step S16 and step S18, the regions where switching of the operation state is prohibited are set separately because the change rate of the current flowing through the motor generator 10 is different between the zero voltage vector and the effective voltage vector. Therefore, it is based on the knowledge that the appropriate region for prohibiting the change of the operation state can be different.

  If a negative determination is made in step S16 or step S18, the process proceeds to step S20. In step S20, the voltage vector V (n + 1) in the next control cycle is the one in which the number of switching terminals in the switching state from the operation state represented by the voltage vector V (n) in the current control cycle is equal to or less than “1”. ) Is temporarily set, it is determined whether any temporarily set operation state satisfies the following condition. This condition is that (a) the error edq (n + 2) is less than or equal to the threshold eth, and (b) the change rate of the error edq (n + 2) is negative (the error edq (n + 2) is the error edq (n + 1). Is the condition that the logical product of the Here, the threshold value eth defines a boundary of a region (relative speed evaluation region) for selecting an appropriate operation state while the error edq (n + 2) stays in the region defined in steps S16 and S18 for a long time. belongs to.

  Note that the number of switching terminals in the switching state from the operation state represented by the voltage vector V (n) in the current control cycle is “1” or less is as follows. That is, if the voltage vector V (n) is the effective voltage vector Vi (i = 1 to 6), whether the voltage vector V (n + 1) is the voltage vector Vi−1, Vi, Vi + 1 (i: mod 6). The zero voltage vector. However, as the zero voltage vector, if V (n) = V2k (k = 1 to 3), the zero voltage vector V7 is selected. If V (n) = V2k−1, the zero voltage vector V0 is selected. select. FIG. 4A shows four voltage vectors that can be temporarily set as the voltage vector V (n + 1) when V (n) = V1. Further, when the current voltage vector V (n) is the zero voltage vector V0, as shown in FIG. 4B, the voltage vector V (n + 1) is changed to an odd voltage vector V1, V3, V5 or a zero voltage vector. V0. Further, when the current voltage vector V (n) is the zero voltage vector V7, as shown in FIG. 4C, the voltage vector V (n + 1) is converted into an even voltage vector V2, V4, V6 or a zero voltage vector. V7.

  When a positive determination is made in step S20, the process proceeds to step S22. Here, among those satisfying the conditions (a) and (b) above, the norm of the difference between the vectors of the predicted currents ide (n + 1), iqe (n + 1) and the predicted currents ide (n + 2), iqe (n + 2) ( The voltage vector corresponding to the one having the smallest change rate ΔIdqe (n + 2)) is selected as the voltage vector representing the operation state in the next control cycle of the inverter IV. This is a setting for reducing the switching frequency of the switching state. That is, when the rate of change ΔIdqe (n + 2) is large, the actual currents id and iq change greatly during one control cycle Tc, so that it is necessary for the error edq to exceed “α · eth” or “β · eth”. Time is shortened. In this case, a negative determination is made in steps S16 and S18, and the process proceeds to step S20, so that the voltage vector is changed and the switching state is likely to be switched. On the other hand, when the rate of change ΔIdqe (n + 2) is small, the amount of change in the actual currents id and iq during one control cycle Tc is small, so that the error edq is “α · eth” or “β · eth”. It takes a long time to exceed the limit, and as a result, it is difficult to change the switching state. This is because the vector indicating the change in the error edq (the relative velocity vector of the predicted currents ide and iq with respect to the command currents idr and iqr) is the difference between the average output voltage (fundamental voltage) of the inverter IV and the current voltage vector. It is because it is expressed by. That is, in this case, in a steady state where the changes in the command currents idr and iqr are small, there is a high probability that the same voltage vector is evaluated as a voltage vector that minimizes the relative speed even in the next control cycle. On the other hand, since there is a proportional relationship between the relative speed and the rate of change ΔIdqe (n + 2) in the steady state, there is a high probability that the same voltage vector is evaluated as a voltage vector that minimizes the rate of change ΔIdqe (n + 2). Become.

  On the other hand, if a negative determination is made in step S20, in step S24, the condition that (c) error edq (n + 2) is less than or equal to twice the threshold value eth and (d) error edq (n + 2) in step S24. It is determined whether or not the logical product of the change rate of ()) is negative can be satisfied. If the determination in step S24 is affirmative, in step S26, the number of switching state switching terminals from the operation state represented by the voltage vector V (n) in the current control cycle is equal to or less than “1”. Adopt zero voltage vector.

  On the other hand, if a negative determination is made in step S24, in step S28, the number of switching terminals in the switching state from the operation state represented by the voltage vector V (n) in the current control cycle becomes “1” or less. Of the operating states, the one that minimizes the error edq (n + 2) is determined as the final operating state.

  In addition, when the process of said step S22, S26, S28 is completed, or when affirmation determination is made in step S16, S18, this series of processes are once complete | finished.

  When the negative determination is made in steps S16 and S18, the case shown in FIG. 5A and the case shown in FIG. 5B are included. In FIG. 5A, the error edq (n + 1) is less than or equal to the threshold eth until the next control cycle (timing of “n + 1”) depending on the operation state expressed by the voltage vector V (n) in the current control cycle. Shows the case. Here, there are a plurality of operation states newly employed in the next control cycle in which the error edq (n + 2) is equal to or less than the threshold value eth. For this reason, the one that minimizes the change speed under the condition that the error edq is reduced is adopted.

  On the other hand, FIG. 5B shows that the operation state represented by the voltage vector V (n) in the current control cycle is adopted in the next control cycle (timing of “n + 1”), so that the next control cycle. Up to (timing of “n + 2”), the case where the error edq (n + 2) exceeds “α · eth” or “β · eth” is shown. For this reason, in this case as well, the operation state can be changed in the next control cycle so that the change speed is minimized. Incidentally, as a result, when the error edq (n + 2) actually exceeds “α · eth” or “β · eth”, the one with the smallest change rate is considered again. In other words, in this case, a case where the change speed is minimized is examined again by shifting from the region where the actual error is “α · eth” or “β · eth” or less to the relative velocity evaluation region. It will be.

  FIG. 6 shows the processing for setting the coefficients α and β according to the present embodiment. This process is repeatedly executed at the control cycle Tc.

  In this series of processes, first, in step S30, it is determined whether or not the value of the counter that counts the period during which the values of the coefficients α and β are continued is equal to or greater than a threshold value. Here, the threshold value is for defining the continuous period. If a negative determination is made in step S30, the counter is incremented in step S32.

  On the other hand, if a positive determination is made in step S30, the counter is cleared and the 2-bit address is updated in step S34. This address is for designating the values of the coefficients α and β. The reason for this address being 2 bits is that, in the present embodiment, four combinations are exemplified as the coefficients α and β.

  When the processes of steps S32 and S34 are completed, the coefficients α and β are variably set according to the address in step S36. In the present embodiment, the coefficients α and β are set so that the coefficient α is statistically larger than the coefficient β and also causes a reverse phenomenon in which the coefficient β is larger than the coefficient α. Set. Here, the reason why the coefficient α is set to be statistically larger than the coefficient β is that the change rate ΔIdq (n + 2) is likely to be larger for the effective voltage vector. That is, when the rate of change ΔIdq (n + 2) is large, if the coefficient β is excessively large, the degree of surplus may be excessively large when the error edq (n + 2) exceeds “β · eth”. Further, the reason why the reverse rotation phenomenon in which the coefficient β is larger than the coefficient α is also set to suppress a situation where the sign of the difference between the current flowing through the motor generator 10 and the command current is biased.

  FIG. 7A shows the high-frequency current, and FIG. 7B shows the phase current in comparison with the present embodiment and the comparative example. Here, the comparative example shows a case where an operation state selection process in which the change rate ΔIdq (n + 2) is the minimum among the cases where the error edq is equal to or less than the threshold eth is performed. As shown in the figure, the harmonic current of the comparative example is larger, but this is considered to be caused by not considering the above condition (a).

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

  (1) The absolute value (error edq (n + 2)) of the difference between the predicted currents ide (n + 2) and iqe (n + 2) and the command currents idr and iqr is equal to or less than the threshold eth and the specified value α · eth (β · eth ) If it is determined that the value is equal to or greater, the operation state is changed to a state in which the error edq (n + 2) is reduced and the change rate ΔIdq (n + 2) is minimized. Thus, the operation state can be reviewed before the difference between the actual current and the command current becomes equal to or greater than the specified value α · eth (β · eth). In addition, by constantly performing the above determination, it is possible to change to an operation state in which the change rate ΔIdq (n + 2) is minimized even after the difference between the actual current and the command current is equal to or less than the threshold value eth. Become. Here, when the difference between the actual current and the command current is equal to or less than the threshold eth, there is a low probability that there are a plurality of operation states that can be equal to or less than the threshold eth. There is a high probability that there are a plurality of operation states that can be eth or less. For this reason, there is a high probability that there are a plurality of operation states that reduce the error edq (n + 2). As a result, it is possible to select a plurality of candidates that minimizes the change rate ΔIdq (n + 2).

  (2) Specified values α · eth and β · eth that define areas where the change of the operation state is prohibited, depending on whether the voltage vector expressing the current operation state is a zero voltage vector or an effective voltage vector Set separately. As a result, the specified value can be set more appropriately in view of the fact that the change rate of the control amount can be different between when the zero voltage vector is used and when the effective voltage vector is used.

(3) The specified values α · eth and β · eth are variable according to time in such a manner that the values can be smaller than the threshold value eth. Thereby, it can suppress that the steady deviation tendency arises.
<Second Embodiment>
Hereinafter, the second embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  FIG. 8 shows a processing procedure of model predictive control according to the present embodiment. This process is repeatedly executed at a predetermined cycle (control cycle Tc).

  In this series of processing, after the processing in steps S10 and S12 of FIG. 3 is performed in steps S40 and S42, the voltage vector V (n) employed at the current update timing is expressed in step S44. It is determined whether or not the error edq (n + 2) when the operation state is adopted at the next update timing is equal to or less than the threshold value eth. If a negative determination is made in step S44, in step S46, the operation state in which the number of switching terminals from the operation state represented by the voltage vector V (n) in the current control cycle is “1” or less. Among them, the one that minimizes the error edq (n + 2) is determined as the final operation state. In step S48, the permission flag for permitting the change of the operation state is turned on. In this process, the error edq (n + 2) when the operation state expressed by the voltage vector V (n) adopted at the current update timing is also adopted at the next update timing exceeds the threshold eth. It is for memorizing the history.

  On the other hand, if an affirmative determination is made in step S44, it is determined in step S50 whether or not the change permission flag is on. Here, after a negative determination is made in step S44, the change permission flag is turned on, for example, when an affirmative determination is made for the first time in step S44. In this case, in step S52, the error edq (n + 1) assumed to be realized by the operation state represented by the voltage vector V (n) adopted at the current update timing is equal to or less than the threshold eth. Determine whether or not. This process is for determining whether or not the absolute value of the difference between the current flowing through the motor generator 10 and the command current is equal to or less than the threshold value eth.

  If a positive determination is made in step S52, the process proceeds to step S54. In step S54, an operation state in which the number of switching terminals from the operation state represented by the voltage vector V (n) in the current control cycle is “1” or less satisfies the following condition. Determine as the operation state. That is, (e) the error edq (n + 2) is less than or equal to the threshold eth, (f) the error edq (n + 2) is reduced compared to the error edq (n + 1), and (c) the change rate Idq (n + 2) is This is a logical product condition of the three conditions of becoming the minimum.

  When the process of step S54 is completed, the change permission flag is turned off in step S56.

  In addition, when the process of said step S48, S56 is completed, or when negative determination is made in step S50, S52, this series of processes is once complete | finished.

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

(4) After the timing (S52: YES) at which the difference between the actual current and the command current (edq (n + 1)) shifts from the state above the threshold value eth to the state below the threshold value (S52: YES), based on the rate of change ΔIdq (n + 2) The operation state was selected. Thereby, it is possible to select an operation state in which the time for staying in the region that is equal to or less than the threshold value eth is long.
<Third Embodiment>
Hereinafter, the third embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  In the present embodiment, torque and magnetic flux are directly controlled variables, and the operation state of the inverter IV is determined using these command values and predicted values as inputs.

  FIG. 9 shows a system configuration according to the present embodiment. In FIG. 9, processes corresponding to the processes shown in FIG. 1 are given the same reference numerals for convenience.

  As shown in the figure, the torque / magnetic flux prediction unit 37 predicts the magnetic flux vector Φ and the torque T of the motor generator 10 based on the predicted currents ide and iqe. Here, the magnetic flux vector Φ = (Φd, Φq) is predicted by the following equations (c5) and (c6), and the torque T is predicted by the following equation (c7).

Φd = Ld · id + φ (c5)
Φq = Lq · iq (c6)
T = P (Φd · iq−Φq · id) (c7)
Incidentally, the number P of pole pairs is used in the above formula (c7).

  On the other hand, in the magnetic flux map 38, the command magnetic flux vector Φr is set based on the required torque Tr. Here, the command magnetic flux vector Φr is set according to a request for realizing, for example, maximum torque control that can obtain the maximum torque with the minimum current among those satisfying the required torque Tr.

  In the operation state determination part 34a, the process which changed the electric current into the magnetic flux and the torque in the corresponding process concerning the said 1st Embodiment is performed. That is, when the current operation state is temporarily set as the operation state at the next update timing, the difference between the predicted torque Te and the required torque Tr and the difference between the components of the predicted magnetic flux vector Φe and the command magnetic flux vector Φr. If the value to be quantified based on the threshold value is equal to or less than the threshold value and equal to or greater than the specified value, an operation state that remains for a long time in the region that is equal to or less than the specified value is considered. That is, the one having the smallest sum of the change rate of the predicted torque Te and the change rate of the predicted magnetic flux vector Φe is selected.

The quantification is determined based on the sum of values obtained by multiplying the squares of these differences by weighting factors a and b (a ≠ b, a ≠ 0, b ≠ 0). Here, the weighting factors a and b are taken into consideration that the magnitudes of torque and magnetic flux are different. That is, for example, when setting a unit in which the numerical value of the torque is larger, the torque deviation tends to be larger. Therefore, when the weighting factors a and b are not used, the voltage vector has a low magnetic flux controllability. However, there is a possibility that disadvantages such as that the evaluation does not become so low. For this reason, the weight coefficients a and b are used as means for compensating for the difference in absolute value of the plurality of input parameters for evaluation.
<Other embodiments>
Each of the above embodiments may be modified as follows.

"Region determination means"
In the first embodiment, the operation state represented by the voltage vector can be changed at all times while in the relative speed evaluation region. However, the present invention is not limited to this, and may be limited to, for example, a predetermined number of updatable timings. .

"About migration judgment means"
In the second embodiment, the error edq (n + 1) between the predicted current and the command current corresponding to the operation state currently employed is less than or equal to the threshold value eth, so that the relative speed evaluation region has shifted from the inside to the inside. Although it is determined that the situation is present, the present invention is not limited to this. For example, when the error edq (n + 2) between the predicted current and the command current corresponding to the temporarily set operation state is equal to or less than the threshold eth and there are a plurality of operation states in which the error edq (n + 2) decreases, the above-described situation You may judge that. This is because the difference between the control amount realized by the currently adopted operation state and its command value enters the relative speed evaluation region, so that the error can be reduced to a threshold value or less and the error can be reduced. This is because it is considered that there are a plurality of operation states that change to. The reason that a plurality of candidates can exist in this way is the reason for providing the relative speed evaluation area. However, since there is no guarantee that a plurality of candidates always exist, the specified number of times can be changed from the timing when the error edq (n + 2) between the predicted current and the command current corresponding to the temporarily set operation state is equal to or less than the threshold eth. When the plurality of candidates do not exist within the timing, this determination may be aborted.

"Relative speed evaluation area"
Only when the current voltage vector is an effective voltage vector, it is good also as an area | region which permits the change to the operation state which makes a relative speed the minimum.

  At this time, instead of selecting the error edq (n + 2) smaller than the error edq (n + 1), the error edq (n + 2) may be selected to be equal to or less than the error edq (n + 1).

"Relative speed prediction means"
It is not limited to the difference between the predicted current Idq (n + 2) as the current value at the next update of the voltage vector V (n + 1) and the predicted current Idq (n + 1) as the current value generated by the voltage vector V (n). For example, according to the above (c3) and (c4), based on the predicted current Idq (n + 1) and the voltage vector V (n + 1) as the current values at the next update of the voltage vector V (n + 1), the voltage vector V ( The change rate of the d-axis current and the change rate of the q-axis current generated by (n + 1) can be calculated. Therefore, the change rate may be calculated based on this.

  The present invention is not limited to predicting only the rate of change of current caused by the next voltage vector V (n + 1). For example, in the case of sequentially predicting up to the control amount by the operation of the inverter IV at the update timing several control cycles ahead, these average speeds may be predicted.

  The relative speed between the command currents idr and iqr and the predicted currents ide and iqe may be evaluated. Here, the changing speed of the command currents idr and iqr is the difference between the command currents idr (n + 2) and iqr (n + 2) and the command currents idr (n + 1) and iqr (n + 1), and the predicted currents ide and iqe A vector generated by the difference from the change speed is a relative speed vector. Here, when the change rate ΔIdqe (n + 2) is replaced with the norm of the relative velocity vector in the first embodiment, when the command currents idr and iqr do not change, it is mathematically equivalent to the process of the first embodiment. Become.

“Relative velocity quantification method”
For example, in the first embodiment, the absolute value of the difference between the predicted current ide (n + 2) and the predicted current ide (n + 1) and the absolute value of the difference between the predicted current iqe (n + 2) and the predicted current iqe (n + 1). The weighted average processing value may be used as a parameter for evaluating the relative speed (change speed). In short, in order to quantify the fact that the evaluation becomes lower as the relative speed is larger, it may be quantified by a parameter having a positive or negative correlation with the relative speed.

“Parameters for evaluating the degree of deviation between the controlled variable and its command value”
For example, in the first embodiment, the absolute value of the difference between the predicted current ide (n + 2) and the command current idr (n + 2) and the absolute value of the difference between the predicted current iqe (n + 2) and the command current iqr (n + 2) The weighted average processing value may be used as a parameter for evaluating the degree of deviation. In short, in order to quantify that the evaluation becomes lower as the degree of divergence is larger, it may be quantified by a parameter having a positive or negative correlation with the degree of divergence.

"About the threshold eth"
The threshold value eth is not limited to those that are variably set according to the required torque Tr, electrical angular velocity ω, and power supply voltage VDC, but is variably set according to one or two of these three parameters. There may be. Further, instead of the required torque Tr, an estimated torque estimated from the actual currents id and iq may be used. Further, actual currents id and iq and command currents idr and iqr may be used instead of the required torque Tr.

  The threshold value eth may be a fixed value. However, in this case, it is desirable that an object to be compared with the threshold value eth is an error normalized by the absolute value of the control amount (ratio of the norm of the error vector to the norm of the command current vector).

“Regulated values (α · eth, β · eth)”
The voltage vector expressing the operation state is not limited to one set separately depending on whether the voltage vector is a zero voltage vector or an effective voltage vector.

  Moreover, it is not restricted to what changes a regulation value according to progress of time.

“Temporarily set operation status”
The number of switching phases in the switching state is not limited to “1” or less, and may be “2” or less. Moreover, all of voltage vectors V0-V7 may be sufficient.

"About controlled variables"
The control amount used for determining the operation of the inverter IV based on the command value and the predicted value is not limited to any of torque, magnetic flux, and current. For example, only torque or magnetic flux may be used. For example, torque and current may be used. Here, when the control amount is other than the current, the direct detection target by the sensor may be other than the current.

  In each of the above embodiments, the ultimate control amount of the rotating machine (the control amount that is ultimately required to be a desired amount regardless of whether or not it is a prediction target) is the torque. For example, the rotational speed may be used.

"others"
The rotating machine is not limited to an embedded magnet synchronous machine, and may be an arbitrary synchronous machine such as a surface magnet synchronous machine or a field winding type synchronous machine. Furthermore, it is not limited to a synchronous machine, but may be an induction rotating machine such as an induction motor.

  The rotating machine is not limited to that mounted on a hybrid vehicle, but may be mounted on an electric vehicle. Further, the rotating machine is not limited to the one used as the main machine of the vehicle.

  In the above embodiment, it is assumed that the stator windings are star-connected, but the present invention is not limited to this and may be delta-connected. In this case, the terminal and phase of the rotating machine do not match.

  The DC voltage source is not limited to the high voltage battery 12 and may be, for example, an output terminal of a converter that boosts the voltage of the high voltage battery 12.

  The power conversion circuit configured to include a switching element that opens and closes between a voltage applying unit having a plurality of different voltage values and a terminal of the rotating machine is not limited to the inverter IV. For example, it may be provided with a switching element that selectively opens and closes between the voltage application means for applying three or more different voltages to each terminal of the multiphase rotating machine and the terminal of the rotating machine. . An example of a power conversion circuit for applying three or more different voltages to a terminal of a rotating machine is exemplified in Japanese Patent Application Laid-Open No. 2006-174697.

  DESCRIPTION OF SYMBOLS 10 ... Motor generator, 12 ... High voltage battery (one Embodiment of DC voltage source), 14 ... Control apparatus (One Embodiment of the control apparatus of a rotary machine).

Claims (5)

ON / OFF operation of switching elements constituting a power conversion circuit including a switching element that opens and closes between a voltage applying means having a plurality of different voltage values and a terminal of a rotating machine In the control device for a rotating machine that controls a control amount having at least one of the current flowing through the rotating machine, the torque of the rotating machine, and the magnetic flux of the rotating machine,
A control amount prediction means for temporarily setting an operation state of the power conversion circuit expressed by a voltage vector determined by the on / off operation, and predicting the control amount realized by the temporarily set operation state;
The predicted controlled variable and the command value of the control period of the next definitive when the operational state of the control period is temporarily set to the current the same operating conditions and have been operated state adopted in the control period of after next of the power converter circuit If the absolute value of the difference between the two is defined as an absolute value one after another and the absolute value is equal to or less than a predetermined value, the operation state of the next control cycle is changed from the operation state employed in the current control cycle. Limiting means to limit
The operation state of the power conversion circuit expressed by a voltage vector determined by the on / off operation is temporarily set in a plurality of ways, and the predicted control amount and the command according to each of the temporarily set operation states An error prediction means for predicting an error from the value;
The absolute value of the difference between the control amount and the command value in the next control cycle that is assumed to be realized by the operation state adopted in the current control cycle is defined as the next error, and the absolute value after the next time is in situations where there What Do less greater threshold than the prescribed value exceeds a and該規value, the out of temporarily set operational state to the plurality of ways, the error of the control cycle after next predicted by the error estimating means Is an operation state that changes to a side that decreases with respect to the next error, and the target operation state that minimizes the rate of change of the error is different from the operation state adopted in the current control cycle . Changing means for changing the operation state of the next control cycle to the target operation state;
A control device for a rotating machine. ON / OFF operation of switching elements constituting a power conversion circuit including a switching element that opens and closes between a voltage applying means having a plurality of different voltage values and a terminal of a rotating machine In the control device for a rotating machine that controls a control amount having at least one of the current flowing through the rotating machine, the torque of the rotating machine, and the magnetic flux of the rotating machine,
A control amount prediction means for temporarily setting an operation state of the power conversion circuit expressed by a voltage vector determined by the on / off operation, and predicting the control amount realized by the temporarily set operation state;
The predicted control amount and its command value of the next control cycle when the operation state of the next control cycle of the power conversion circuit is provisionally set to the same operation state as that adopted in the current control cycle, The absolute value of the difference between the two is defined as an absolute value one after another, and when the next successive absolute value is less than or equal to the threshold, it is limited to change the operation state of the next control cycle from the operation state adopted in the current control cycle Limiting means to
The operation state of the power conversion circuit expressed by a voltage vector determined by the on / off operation is temporarily set in a plurality of ways, and the predicted control amount and the command according to each of the temporarily set operation states An error prediction means for predicting an error from the value;
The absolute value of the difference between the control amount and the command value in the next control cycle that is assumed to be realized by the operation state adopted in the current control cycle is defined as the next error, and the absolute value after the next time is The operation temporarily set in a plurality of ways only during a specified number of times closest to the transition timing after the transition timing from the state above the threshold to the state below the threshold. Among the states, there is an operation state in which the error of the next control cycle predicted by the error prediction unit changes to a side where the error decreases with respect to the next error, and the target operation state in which the rate of change of the error is the minimum On the condition that the operation state is different from the operation state adopted in the current control cycle, the operation state of the next control cycle is determined even if the absolute value is not more than the threshold value one after another. And the change means that allows you to change the serial target operation state,
A control device for a rotating machine. Wherein the prescribed value, the rotating machine of the control device according to claim 1, wherein the set to each other at zero voltage vector and the effective voltage vectors of the voltage vector representing the operation state of the power conversion circuit.   The control device for a rotating machine according to claim 3, wherein the specified value is variable according to time in a manner that can be a value smaller than the threshold value. The power conversion circuit, any of claims 1-4, characterized in that the DC-AC converter comprising a switching element for selectively connecting said rotating machine terminals to each of the positive electrode and the negative electrode of the DC voltage source The control device for a rotating machine according to Item 1.

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