JP2014230467A - Induction motor control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect abnormality such as erroneous wiring of an induction motor.SOLUTION: An induction motor control device comprises: one or more induction motors 101-104; a torque control section which stops torque control of the induction motors 101-104 in response to a test command (t), applies a fixed voltage in a sinusoidal wave shape to the induction motors 101-104 and allows currents to flow; current detection sections 201-204 for detecting the currents inputted to the induction motors 101-104; a current vector calculation section 5 for calculating rotation directions of current vectors i1-i4 of the currents inputted to the induction motors 101-104; and a rotation direction abnormality detection section 6 for detecting that any one of the rotation directions of the current vectors i1-i4 is abnormal.

Description

  The present invention relates to an induction motor control device that controls one or more induction motors.

  In general, in vehicles such as trains, the torque of a plurality of induction motors is collectively controlled to perform cart control or single vehicle control.

  FIG. 2 is a block diagram showing a configuration example of a conventional induction motor control apparatus that performs such control. In FIG. 2, four induction motors 101 to 104 are shown, but any number of induction motors may be used. Hereinafter, it is assumed that there are four induction motors and that the motor constants of the induction motors 101 to 104 are the same, but other configurations may be adopted.

  In the induction motor control apparatus shown in FIG. 2, as described in Patent Document 1 and the like, a rotation speed detector is not attached to the induction motor from the viewpoint of miniaturization and the like. Then, the rotational speed ωm of the induction motor is calculated from the total current i of the induction motor and the voltage command v input to the power converter 2. The procedure is shown below.

  The total current detection unit 200 detects a total current i that is the sum of the three-phase currents flowing from the power conversion unit 2 to the individual induction motors 101 to 104.

  The voltage system magnetic flux calculation unit 3 calculates the induction motor magnetic flux φ from the total current i and the voltage command v input to the power conversion unit 2 by the equation (1).

  Here, R1 is a primary resistance composite value of all induction motors, L2 is a secondary self-inductance composite value, M is a mutual inductance composite value, and Lek is a leakage inductance composite value. The leakage inductance composite value Lek is given by the following equation (2).

  Here, L1 is a primary self-inductance composite value of the all induction motor.

  The rotation speed calculation unit 4 calculates the induction motor rotation speed ωm from the total current i and the induction motor magnetic flux φ using the equations (3) to (5).

  Here, R2 is a secondary resistance composite value of all induction motors, and FA and FB are each component of induction motor magnetic flux φ.

  The induction motor rotational speed ωm calculated by Expression (5) is an average value of the rotational speeds ωm1 to ωm4 of the induction motors 101 to 104, as shown in Expression (6).

  Here, ωm1 to ωm4 are rotational speeds of the induction motors 101 to 104, respectively.

  Next, based on the induction motor rotational speed ωm and the total current i, the torque control unit 1 determines a voltage command such that the induction motor magnetic flux φ becomes the magnetic flux command φ * and the total torque of all the induction motors becomes the torque command τ *. Output v.

  The power converter 2 amplifies the voltage command v and supplies power to the induction motors 101 to 104 that are loads.

  With the above configuration, it is possible to control the total torque of all the induction motors to follow the torque command τ *. In the example shown here, since each induction motor has the same motor constant, each induction motor outputs a torque (τ * / 4) that is 1/4 of the torque command τ *.

JP-A-11-69895

  The conventional induction motor control apparatus as described above has the following problems.

  The induction motor control device performs the above-described control based on a known motor constant of the induction motor.

  Here, when one of the induction motors is miswired, specifically, the case where the V phase and the W phase of the induction motor 101 are connected to the W phase and the V phase of the power conversion unit 2, respectively. Think.

  In this case, the induction motor 101 behaves so as to have different motor constants for the same voltage input as compared to the case where the wiring is normally performed. As a result, since the motor constant of the induction motor is different from that assumed by the induction motor control device, the induction motor may not be correctly controlled, and overcurrent may occur.

  In such a case, it is necessary to quickly detect and deal with erroneous wiring of the induction motor. However, a vehicle with a train is usually not controlled by one induction motor control device, and for example, a plurality of vehicles each having an induction motor control device are connected and operated. Therefore, even if one of the induction motors is miswired, the operation of the entire vehicle is maintained and may not be noticed until a major abnormality such as overcurrent occurs.In the worst case, There was a risk of destruction of the power converter element.

  The present invention has been made to solve such problems, and an object of the present invention is to detect an abnormality such as an incorrect wiring of an induction motor.

  The induction motor control device according to the present invention stops torque control of each induction motor in response to a test command with one or more induction motors, applies a constant sine wave voltage to each induction motor, A torque control unit for supplying current, a current detection unit for detecting the current input to each induction motor, a current vector calculation unit for obtaining a rotation direction of a current vector of the current input to each induction motor, and the current A rotation direction abnormality detection unit that detects that any of the rotation directions of the vector is abnormal.

  And preferably, the current vector calculation unit obtains the rotation direction of the current vector from the outer product of the differentiation of the current vector and the current vector, and the rotation direction abnormality detection unit An abnormality in the rotation direction of the current vector is detected based on the sign of the component of the outer product that is orthogonal to the current vector.

  According to the induction motor control device of the present invention, it is possible to detect an abnormality such as an incorrect wiring of the induction motor.

It is a block diagram which shows the example of 1 structure of the induction motor control apparatus of this invention. It is a block diagram which shows the example of 1 structure of the conventional induction motor control apparatus. It is a figure which shows the relationship between the rotation direction RotX of the electric current vector of the electric current input into an induction motor, and KX which a rotation direction abnormality detection part calculates.

  As shown in FIG. 1, the induction motor control device according to the embodiment of the present invention is provided with a rotation direction abnormality detection unit 6 and a current vector calculation unit 5, so that any one of the induction motors 101 to 104 is provided. Abnormalities such as incorrect wiring can be detected. And the cab 7 can receive the detection signal K which the rotation direction abnormality detection part 6 outputs, and can display that it is miswired, for example on a cab display part.

  FIG. 1 is a block diagram showing a configuration example of the present invention. In addition, about the component similar to FIG. 2 mentioned above, the same code | symbol as FIG. 2 is attached | subjected and description is abbreviate | omitted. Further, as described above, it is assumed that there are four induction motors and the motor constants of the induction motors 101 to 104 are the same, but other configurations may be adopted.

  Current detectors 201 to 204 detect currents input to induction machines 101 to 104, respectively. In the present embodiment, the current vector calculation unit 5 converts the three-phase currents detected by the current detection units 201 to 204 and input to the induction machines 101 to 104 into two-phase currents in the αβ coordinate system. Here, the α axis coincides with the U-phase axis of each induction machine, and the β axis is orthogonal to the α axis.

  The current vector calculation unit 5 uses the current vectors i1 to i4 to obtain the outer product of the differentiation of the current vectors i1 to i4 and the current vector as in the equations (7) to (10).

  Here, the symbol “p” indicates a differential operator. The elements of the vectors Rot1 to Rot4 are represented as (0, 0, rot 1), (0, 0, rot 2), (0, 0, rot 3), (0, 0, rot 4), and current vectors i1 to i4. The symbols rot1 to rot4, which are components orthogonal to each other, indicate the rotation direction of the current vectors i1 to i4.

  In this embodiment, the differentiation of the current vectors i1 to i4 is calculated based on the amount of change of the current vectors i1 to i4 acquired at a predetermined sampling period. However, the differentiation of the current vectors i1 to i4 is performed by other methods. Can also be requested.

  The rotation direction abnormality detection unit 6 receives the values rot1 to rot4 obtained by the current vector calculation unit 5 and outputs a detection signal K based on the signs of rot1 to rot4. The detection signal K indicates that one of the rotation directions of the current vectors i1 to i4 of the currents input to the induction motors 101 to 104 is abnormal.

  A method for calculating the detection signal K will be described in more detail. First, rotation direction information K1 to K4 of each induction motor 101 to 104 is obtained by the following equations (11) to (14). FIG. 3 shows the relationship between rotX (X = 1 to 4 in this embodiment) shown in the equations (11) to (14) and KX.

  Then, the detection signal K is obtained by taking the product of K1, K2, K3, and K4 as shown in the equation (15) and output. Note that the symbol “x” in Equation (15) indicates a simple product.

  That is, the detection signal K is 1 if all of K1, K2, K3, and K4 are positive values, and 0 if any of them is 0 or less.

  Based on the detection signal K, the cab 7 displays the presence or absence of incorrect wiring of the induction motor on a cab display stand (not shown). It is also possible to display which induction motor is miswired.

  The cab 7 constituting the test command creation unit receives the detection signal K obtained by the rotation direction abnormality detection unit 6 and the test command t, obtains the test command T by taking the logical product of K and t, Output.

  The test command t is set to 1 when an erroneous wiring of the induction machines 101 to 104 is detected, and is set to 0 in other cases. The case where the test command t is set to 1 is, for example, after vehicle manufacture or after replacement of the electric induction machine.

  When the test command T is on (1), the torque control unit 1 stops the torque control of the induction motors 101 to 104, and when the induction motors 101 to 104 are correctly wired, the above-described rot1, rot2 , Rot3 and rot4 are each output a constant sinusoidal voltage command v so that currents flowing through the induction motors 101 to 104 are positive values.

  On the other hand, when the test command T is off (1), the torque control unit 1 determines that the magnetic flux and total torque of all the induction motors are the magnetic flux command φ * and the torque command τ based on the induction motor rotational speed ωm and the total current i. A voltage command v such that * is output, and torque control of each of the induction motors 101 to 104 is performed.

  The power converter 2 amplifies the voltage command v and supplies power to the induction motors 101 to 104 that are loads. The power can be supplied by PWM control or the like.

  With the above configuration, by inputting a test command t that is an external signal to the cab 7, it is detected that any of the induction motors has been miswired before starting the train operation. be able to.

  In the embodiment shown in FIG. 1, the induction motor rotation speed ωm is calculated by the rotation speed calculation unit 4, but the induction motor rotation speed can be measured instead.

  The induction motor control device according to the present invention is suitable for controlling a plurality of induction motors when used in a vehicle such as a train.

101, 102, 103, 104 Induction motors 201, 202, 203, 204 Current detection unit 200 Total current detection unit 1 Torque control unit 2 Power conversion unit 3 Magnetic flux calculation unit 4 Rotational speed calculation unit 5 Current vector calculation unit 6 Abnormal rotational direction Detector 7 cab

Claims (2)

One or more induction motors,
A torque control unit that stops torque control of each induction motor in response to a test command, applies a constant sinusoidal voltage to each induction motor, and flows current;
A current detector for detecting the current input to each induction motor;
A current vector calculation unit for obtaining a rotation direction of a current vector of the current input to each induction motor;
A rotation direction abnormality detection unit for detecting that any of the rotation directions of the current vector is abnormal;
An induction motor control device comprising: The current vector computing unit obtains the rotation direction of the current vector from the outer product of the differentiation of the current vector and the current vector,
The induction motor control device according to claim 1, wherein the rotation direction abnormality detection unit detects an abnormality in the rotation direction of the current vector based on a sign of a component of the outer product that is orthogonal to the current vector.

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