JP2010166715A - Controller and control system for rotating machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem of a conventional system that the controllability of torque is not always favorable when controlling the torque of a motor generator by operating an inverter connected to the motor generator. <P>SOLUTION: A controller predicts currents ide and iqe in the case where the operation state of an inverter is set at a voltage vector Vn, based on a power voltage VDC, with the present current detected values id and iq as initial values (step S14). It performs this prediction for all voltage vectors V0-V7 (YES in step S22). It predicts a torque based on these predicted currents (step S28). It uses a voltage vector where the deviation between a predicted torque and a requested torque becomes the minimum, as an actual operation state of the inverter. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device and a control for a rotating machine that controls a torque of the rotating machine by operating a power conversion circuit including a switching element that electrically connects each of a positive electrode and a negative electrode of a DC power source to a terminal of the rotating machine. About the system.

  As this type of control device, as shown in, for example, Patent Document 1 below, when the norm of the output voltage vector of the inverter exceeds a predetermined value, the output of the inverter is to be feedback-controlled to the required torque of the three-phase motor torque. It has also been proposed to manipulate the phase of the voltage. That is, as the operation amount for feedback control of the torque of the three-phase motor estimated from the current flowing through the three-phase motor to the required torque, the phase of the output voltage of the inverter is set, and the phase of the voltage having a predetermined vector norm is set. Operate to this set phase. As a result, the torque of the three-phase motor can be feedback controlled to the required torque.

  Other conventional control devices are also described in, for example, Patent Document 2 below.

Japanese Patent Laid-Open No. 11-299297 Japanese Patent No. 3727268

  By the way, when the torque feedback control is performed as described above, the phase is changed only when the torque of the three-phase motor is separated from the required torque. There is a concern that the torque may become unexpected.

  In addition, not only those that perform feedback control of the torque described above, but those that control the torque of the rotating machine to the required torque, there is a concern that the actual torque may be unexpected, such circumstances are generally common It has become.

  The present invention has been made to solve the above problems, and an object of the present invention is to operate a power conversion circuit including a switching element that electrically connects each of a positive electrode and a negative electrode of a DC power source to a terminal of a rotating machine. Thus, an object of the present invention is to provide a control device and a control system for a rotating machine that can more suitably control the torque of the rotating machine.

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

  According to the first aspect of the present invention, there is provided a rotating machine that controls the torque of the rotating machine by operating a power conversion circuit including a switching element that electrically connects each of a positive electrode and a negative electrode of a DC power supply to a terminal of the rotating machine. In the control device, prediction means for predicting the torque realized by each of the output voltages of the power conversion circuit according to each of the operation states when the operation state of the power conversion circuit is set to a plurality of ways, Operation means for operating the power conversion circuit by determining an actual operation state of the power conversion circuit based on the predicted torque and the target value is provided.

  The current flowing through the rotating machine is determined by the output voltage (input voltage of the rotating machine) of the power converting circuit determined by the input voltage of the power converting circuit and the operation state of the power converting circuit. The current flowing through the rotating machine is a parameter having a correlation with torque. Therefore, the torque can be predicted from the output voltage of the power conversion circuit when the operation state of the power conversion circuit is set. In particular, by setting a plurality of operation states of the power conversion circuit, it is possible to select a more appropriate operation state in controlling the torque of the rotating machine to the target value. For this reason, according to the said invention, the torque of a rotary machine can be controlled more suitably.

  In addition, it is desirable that the prediction means predicts a torque realized when the operation state of the power conversion circuit is set to all of the non-zero vectors and at least one zero vector.

  According to a second aspect of the present invention, in the first aspect of the present invention, the operation means operates the power conversion circuit so as to be in an operation state that minimizes a deviation between the predicted torque and a target value. It is characterized by.

  According to the above invention, the torque of the rotating machine can be suitably brought close to the target value by operating the power conversion circuit.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the prediction means is predicted to include a means for predicting a current flowing through the rotating machine when an operation state of the power conversion circuit is set. Means for predicting the torque based on the current.

  Since the torque of the rotating machine depends on the current flowing through the rotating machine, it can be estimated based on the current flowing through the rotating machine. Further, the current flowing through the rotating machine can be predicted by the voltage applied from the power conversion circuit to the rotating machine. In the above invention, in view of this point, the torque of the rotating machine when the operation state of the power conversion circuit is set can be predicted by predicting the current flowing through the rotating machine.

  The invention according to claim 4 is the invention according to claim 3, wherein the operation means operates the power conversion circuit while avoiding an operation state in which the predicted current exceeds an allowable range. To do.

  In the said invention, when controlling a torque, it can avoid that an electric current becomes an excessively inappropriate value.

  A fifth aspect of the present invention is a rotating machine control system comprising the rotating machine control device according to any one of the first to fourth aspects and the power conversion circuit.

  In the above invention, since the operation means is provided, a system with high torque controllability is realized.

The system block diagram concerning one Embodiment. The figure which shows a voltage vector. The flowchart which shows the process sequence of the torque control concerning the said 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 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 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 a high voltage battery 12 via an inverter IV and a boost converter CV. Here, the boost converter CV boosts the voltage (for example, “288V”) of the high-voltage battery 12 up to a predetermined voltage (for example, “666V”). On the other hand, the inverter IV includes a series connection body of the switching elements Sup and Sun, a series connection body of the switching elements Svp and Svn, and a series connection body of the switching elements Swp and Swn. The points are connected to the U, V, and W phases of the motor generator 10, respectively. In the present embodiment, insulated gate bipolar transistors (IGBTs) are used as the switching elements Sup, Sun, Svp, Svn, Swp, and Swn. In addition, diodes Dup, Dun, Dvp, Dvn, Dwp, and Dwn are connected in antiparallel to 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 15 that detects a rotation angle θ (electrical angle) of the motor generator 10 is provided. Further, current sensors 16, 17, and 18 that detect currents iu, iv, and iw flowing through the phases of the motor generator 10 are provided. Furthermore, a voltage sensor 19 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 14 constituting the low pressure system via the interface 13. The control device 14 generates and outputs an operation signal for operating the inverter IV and the converter CV based on the detection values of these various sensors. Here, the signals for operating the switching elements Sup, Sun, Svp, Svn, Swp, Swn of the inverter IV are the operation signals gup, gun, gvp, gvn, gwp, gwn. The signals for operating the two switching elements of the boost converter CV are the operation signals gup and gcn.

  The control device 14 operates the inverter IV in order to control the torque of the motor generator 10 to the required torque. In particular, in the present embodiment, the model predictive control for predicting the torque of the motor generator 10 when the operation state of the inverter IV is set and operating the inverter IV so that the torque becomes an operation state close to the required torque is performed. Do. Here, the operation state of the inverter IV will be described first.

  The operation state of the inverter IV can be expressed by eight voltage vectors shown in FIG. Here, for example, the voltage vector representing the operation state (indicated as “lower” in the figure) 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 element A voltage vector representing an operation state (indicated as “upper” in the drawing) in which Sup, 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 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 non-zero 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.

  In this embodiment, the torque of the motor generator 10 when the operation state of the inverter IV is set to each of these eight voltage vectors V0 to V7 is predicted, and based on this, the voltage vector to be in the actual operation state is selected.

  FIG. 3 shows a model prediction control processing procedure according to the present embodiment. The processing shown in FIG. 3 is repeatedly executed by the control device 14 at a predetermined cycle, for example.

In this series of processing, first, in step S10, the current current detection values id and iq are acquired. This process is a process for converting the actual currents iu, iv, and iw detected by the current sensors 16 to 18 into the actual currents id and iq by performing three-phase conversion. In subsequent step S12, parameter n specifying voltage vectors V0 to V7 is set to zero. In the subsequent step S14, the current when the initial value of the current is the actual current id, iq in step S10 and the operation state of the inverter IV is the voltage vector Vn is predicted (currents ide, iq are calculated). In this prediction process, a voltage equation expressed by the following equations (c1) and (c2) is used.
vd = (R + pLd) id−ωLqiq (c1)
vq = ωLdid (R + pLq) iq + ωΦ (c2)
In the voltage equation, the resistance R, the d-axis inductance Ld, the q-axis inductance Lq, the flux linkage constant Φ, and the electrical angular velocity ω of the motor generator 10 are used. The following equation of state (formulas (c3) and (c4)) can be derived by solving these voltage equations for the differential term of the current.
pid
= − (R / Ld) id + ω (Lq / Ld) iq + vd / Ld (c3)
piq
= −ω (Ld / Lq) id− (Rd / Lq) iq + vq / Lq−ωΦ / Lq (c4)
In the present embodiment, the state equation expressed by the above equations (c3) and (c4) is discretized, and the current one step ahead is predicted. Incidentally, in the state equations expressed by the above equations (c3) and (c4), the output voltage vector (vd, vq) is selected when the zero vector (V0, V7) is selected as the operation state of the inverter IV. When a zero vector is selected and a non-zero vector is selected, the vector norm shown in FIG. 2B is used as the input voltage (power supply voltage VDC) of the inverter IV, and this is a vector obtained by dq conversion. . The electrical angular velocity ω may be a value calculated based on a time differential calculation of the rotation angle detected by the rotation angle sensor 15.

  In subsequent step S16, three-phase currents (iue, ive, iwe) are predicted by performing three-phase conversion on the currents ide, iq predicted in step S14. In the subsequent step S18, it is determined whether or not the maximum value of these three-phase currents iue, ive, and iwe exceeds the threshold current Ith. Here, the threshold current Ith is the maximum allowable current of the inverter IV. Here, the maximum allowable current may be an upper limit value that can maintain the reliability of the inverter IV due to its structure. In addition, when a drive circuit that drives the inverter IV has a function of forcibly shutting down the inverter IV due to an excessively large current flowing through the inverter IV, a current that is not shut down. It is good also as an upper limit of.

  When it is determined in step S18 that the threshold current Ith is exceeded, in step S20, the voltage vector Vn is excluded from candidates for the operation state of the inverter IV.

  When the process of step S20 is completed or when a negative determination is made in step S18, it is determined in step S22 whether or not the parameter n is “7”. This process is for determining whether or not the prediction of the current when all of the voltage vectors V0 to V7 are in the operation state of the inverter IV is completed. If a negative determination is made in step S22, the parameter n is incremented by “1” in step S24, and the process proceeds to step S14.

  On the other hand, when it is determined in step S22 that the parameter n is “7”, in step S26, the torque T is predicted based on the currents ide and iq predicted in step S14. Here, the torque T can be predicted by using the following model formula (formula (c5)).

T = p {Φ · ide + (Ld−Lq) · ide · iqe} (c5)
In the subsequent step S28, the voltage vector that minimizes the deviation between the predicted torque and the required torque is determined as the operation state of the inverter IV, and the inverter IV is set so that the actual operation state of the inverter IV becomes this voltage vector. To operate.

  In addition, when the process of step S28 is completed, this series of processes is once complete | finished.

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

  (1) The actual operation state of the inverter IV is determined on the basis of the torque and the required torque that are predicted when the operation state of the inverter IV is set to all the non-zero vectors and the zero vector. Was operated. Thereby, it is possible to select a more appropriate operation state for the control to the required torque.

  (2) The inverter IV was operated so as to obtain an operation state that minimizes the deviation between the predicted torque and the required torque. Thereby, the followability to a required torque can be improved as much as possible.

  (3) When the operation state of the inverter IV is set, the current flowing through the motor generator 10 is predicted, and the torque is predicted based on the predicted current. Thereby, the torque of the motor generator 10 can be suitably predicted.

  (4) The inverter IV was operated avoiding an operation state in which the predicted currents ide and iq exceeded the allowable range. Thereby, when controlling torque, it can avoid that an electric current becomes an excessively inappropriate value.

(Other embodiments)
The above embodiment may be modified as follows.

  In the above embodiment, model predictive control is performed in the entire region, but the present invention is not limited to this. For example, in a region where the voltage usage rate is less than or equal to a predetermined value, the triangular wave PWM control may be performed and the model prediction control may be performed when the voltage usage rate becomes equal to or higher than a predetermined value. Further, for example, the model predictive control may be performed in a region where the voltage usage rate is equal to or lower than a predetermined value, and the well-known rectangular wave control may be performed when the voltage usage rate becomes higher than a predetermined level.

  The model predictive control is not limited to setting a voltage vector for setting the operation state of the inverter IV based on the prediction of torque after one control cycle. For example, based on the prediction of the torque of the motor generator 10 in each control cycle when setting the voltage vector in each of the plurality of control cycles, the voltage vector for operating the inverter IV in each of the plurality of control cycles is set. You may do.

  The model predictive control is not limited to predicting torque when all voltage vectors V0 to V7 that can be in the operation state of the inverter IV are set as the operation state of the inverter IV, but one of the voltage vectors V0 to V7. Each torque when set to a part may be predicted.

  -Model predictive control is not limited to predicting torque based on predicted current. For example, the torque may be predicted by predicting the magnetic flux generated when the operation state of the inverter IV is set.

  In each of the above embodiments, the voltage vector that minimizes the deviation between the estimated torque and the required torque is selected from the candidates. However, the present invention is not limited to this. For example, the command current required by the maximum torque control or field weakening control is set, and the sum of the deviation between the predicted current and the command current and the torque deviation multiplied by a predetermined coefficient and weighted. A function that minimizes this as an evaluation function may be selected. Here, when the current for maximum torque control cannot be realized by the power supply voltage VDC, it is desirable to calculate the value of the evaluation function using the deviation between the command current for field weakening control and the predicted current. At this time, in the situation where the value of the evaluation function is calculated based on the deviation from the command current by the field weakening control, the operation state of the inverter IV in which the predicted current increases the magnetic flux in the magnetic pole direction more than the current by the maximum torque control And the final operating state of the inverter IV may be determined. Here, when the value of the evaluation function is calculated using the deviation from the command current by the field weakening control, the current allowable range is a range in which the magnetic flux in the magnetic pole direction is not strengthened more than the current by the maximum torque control.

  Further, for example, the sum of weighted values obtained by multiplying each of the torque deviation and the switching frequency by a predetermined coefficient may be minimized as an evaluation function. Furthermore, the sum of the number of switching elements for switching the switching state at the time of switching the voltage vector and the deviation of the torque multiplied by a predetermined coefficient may be minimized as an evaluation function. In such a case, the coefficient of the evaluation function may be learned and corrected in accordance with the degree of deviation between the torque actually realized by the voltage vector selected based on the evaluation function and the required torque. Thus, for example, when the accumulated deviation degree becomes excessively large, the followability to the required torque can be improved by performing a correction that relatively increases the weight by which the torque deviation is multiplied.

  -The model used to predict the current is not limited to the model based on the fundamental wave. For example, a model including higher-order components for inductance and induced voltage may be used. The current predicting means is not limited to using a model formula, and may use a map. At this time, the input parameters of the map may be voltage (vd, vq) and electrical angular velocity ω, and may further include temperature and the like. Here, the map is storage means in which output parameter values corresponding to discrete values for input parameters are stored.

  The model used for predicting the current is not limited to a model that ignores iron loss, and may be a model that takes this into consideration.

  In the above embodiment, the torque is predicted using the model based on the predicted current, but the present invention is not limited to this. For example, a map using an estimated current as an input parameter may be used. At this time, temperature or the like may be further added to the input parameters of the map.

  The rotating machine is not limited to an embedded magnet synchronous machine, but 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.

  -As a rotary machine, not only what is mounted in a hybrid vehicle but the thing mounted in an electric vehicle may be sufficient. Further, the rotating machine is not limited to the one used as the main machine of the vehicle.

  The DC power source is not limited to the converter CV but may be a high voltage battery 12. In other words, the input terminal of the inverter IV may be connected to the high voltage battery 12 without providing the converter CV.

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

Claims (5)

In a control device for a rotating machine that controls the torque of the rotating machine by operating a power conversion circuit including a switching element that electrically connects each of a positive electrode and a negative electrode of a DC power source to a terminal of the rotating machine,
Predicting means for predicting torques realized by each of the output voltages of the power conversion circuit according to each of the operation states when the operation states of the power conversion circuit are set to a plurality of ways,
An apparatus for controlling a rotating machine comprising: operating means for operating the power conversion circuit by determining an actual operation state of the power conversion circuit based on the predicted torque and a target value.   2. The control device for a rotating machine according to claim 1, wherein the operation means operates the power conversion circuit so as to be in an operation state in which a deviation between the predicted torque and a target value is minimized.   The said prediction means is provided with a means to predict the electric current which flows into the said rotary machine when the operation state of the said power converter circuit is set, and a means to estimate a torque based on this estimated electric current. Item 3. A control device for a rotating machine according to item 1 or 2.   4. The rotating machine control device according to claim 3, wherein the operating means operates the power conversion circuit while avoiding an operating state in which the predicted current exceeds an allowable range. A control device for a rotating machine according to any one of claims 1 to 4,
A control system for a rotating machine comprising the power conversion circuit.

Images