JP2006262598A - Variable speed controller of motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance torque precision by adding a temperature compensation term. <P>SOLUTION: An inverter 12 for variably controlling a motor 11 is provided, and in order to enhance output torque precision of the motor 11 for a torque command, a torque-current conversion table for converting a torque command and a current command is constituted as a multi-dimension table 13. The multi-dimension table 13 is supplied with a torque command and motor speed information detected by a speed detector 14, and further is supplied with motor temperature information detected by a temperature detector 15, arranged in the motor 11 thus constituting the multi-dimension table 13. When a torque command is imparted to the multi-dimension table 13, a current command is delivered from the multi-dimension table 13. The current command and a current outputted from the inverter 12 are detected by a current detector 16 and are supplied to a deviation unit 17. The output from the deviation unit 17 is amplified by a current amplifier 18, before being supplied to a gate signal generator. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a variable speed control device for an electric motor using an inverter device.

  When high speed torque accuracy (accuracy of motor output torque with respect to torque command) is to be obtained when variable speed control of the motor is performed using an inverter device, nonlinear table compensation is used to model the nonlinear elements of the motor. Is required.

  When this table compensation is applied to the entire operating range of the motor, it becomes a form of a multi-dimensional table that treats the current command as a function of the motor speed and torque command.

  Conventionally, it is a current table based on the torque command and motor speed obtained from the torque command and motor speed image explanatory diagram shown in FIG. 5, and therefore, when the temperature of the motor changes, the induction motor has a resistance component, particularly a secondary component. The resistance fluctuates to cause a torque error, and in the permanent magnet type synchronous motor, the magnetic flux density of the permanent magnet changes to cause a torque error. In contrast, temperature variation compensation using a model has been conventionally used. However, in reality, there are problems in convergence and compensation accuracy due to modeling errors and various detection errors.

  Table 1 is a table illustrating the current command table image according to the torque command and the motor speed shown in FIG.

JP 11-299300 A

  In order to compensate for characteristic changes due to temperature fluctuations of an electric motor, an observer or simulator is configured using an internal model of the electric motor, and means for adjusting fluctuation components so as to match the model from the detected current and voltage has been taken.

  However, the current situation is that the modeling error due to the non-linearity of the motor and the detection error of the current and voltage cause an error, and the convergence, stability, and compensation accuracy are not fully satisfied.

  The present invention has been made in view of the above circumstances, and in order to compensate the output torque accuracy of the motor, a compensation term due to temperature is added to the torque-current conversion table to improve the torque accuracy. It is an object to provide a variable speed control device for an electric motor.

  In order to achieve the above object, the present invention provides a first invention in which a variable speed control of an electric motor is performed by an inverter device using a torque-current conversion table for converting a torque command and a current command. It is a multi-dimensional table in which the temperature information of the motor is added to the torque command and the motor speed information as elements of the current conversion table, and the temperature information of the motor is obtained from the temperature detection means installed in the motor. The torque accuracy was improved.

  The second invention is a device that performs variable speed control of an electric motor with an inverter device using a torque-current conversion table for converting a torque command and a current command, and is obtained from the motor model installed in the inverter device. The variation compensation is performed by referring to the torque-current conversion table from the temperature information, and the reproducibility is improved because the compensation is performed using an error of an element proportional to the temperature information.

  As described above, according to the present invention, since the temperature information of the electric motor is detected and added to the torque-current conversion table, more accurate torque accuracy can be obtained, and the electric motor model can be obtained. By installing, it becomes unnecessary to install a temperature detecting means outside, and it is possible to obtain temperature fluctuation compensation with excellent stability and high accuracy.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of the present invention, which includes an inverter device 12 that variably controls an electric motor (hereinafter referred to as a motor) 11, and for improving the output torque accuracy of the motor 11 with respect to a torque command. In addition, a torque-current conversion table for converting the torque command and the current command is configured in the multidimensional table 13.

  As shown in FIG. 2, the multidimensional table 13 is composed of a plurality of tables having a torque command, motor speed information, and temperature information.

  The multi-dimensional table 13 is supplied with motor speed information detected by a speed detector 14 including a torque command and a tachometer, and motor temperature information obtained by a temperature detector 15 including a thermistor installed in the motor. When supplied, a current command is sent from the multidimensional table 13.

  When a torque command, motor speed information, and temperature information are given to the multidimensional table 13 configured as described above, a current command is sent from the multidimensional table 13. The current command and the current output from the inverter device 12 are detected by a current detector 16 including a current transformer and supplied to a deviation unit 17.

  The deviation unit 17 outputs a deviation between the current command and the current detected by the current detector 16, and the deviation output is amplified by the current amplifier 18. A voltage command is sent from the current amplifier 18, and the voltage command is given to the inverter device 12 via a gate signal generator (not shown) to control the inverter device 12.

  As described above, the torque command, the motor speed, and the motor temperature information are further supplied to the multi-dimensional table 13 to obtain the current command, and the inverter device 12 is controlled based on this command. Torque accuracy can be improved.

  FIG. 3 is a block diagram showing a second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals and described. In the second embodiment, temperature information is not obtained from the temperature detector 15 installed in the motor 11 but is obtained from the motor model 21 provided in the inverter device 12 as follows.

  The motor model 21 receives motor speed information from the speed detector 14, current information from the current detector 16, and voltage command information from the current amplifier 18, and a temperature obtained from an error between the information and the motor model 21. Information (substantially temperature is not necessary. For example, voltage error is also acceptable) is supplied to the multidimensional table 13, and fluctuation compensation is performed with reference to the multidimensional table 13.

  Here, the motor model 21 will be described. An example of the motor model 21 is configured as shown in FIG. 4, for example. In FIG. 4, 21a and 21b are first and second deviators, 21c to 21e are first to third integrators, and 21f is a speed detector.

  The first deviator 21a is given a voltage detection value, an integrated value obtained by integrating the q-axis current detection of the motor and the primary resistance by the first accumulator 21c, and the deviation is supplied to the second accumulator 21d. . The second integrator 21d is provided with the detected speed value of the motor, integrated and supplied to the second deviator 21b. A value obtained by integrating the d-axis current detection and the d-axis inductance by the third accumulator 21e is supplied to the second deviator 21b, and an estimated magnetic flux value is obtained in the deviation output of the second deviator 21b.

  The estimated magnetic flux value changes when the magnet temperature changes, and the motor model output (magnetic flux estimated value) also changes. For this reason, if a function that changes the current according to this value is used, torque control that is more robust against temperature changes can be performed.

  In the case of this second embodiment, the difference from the conventional simple temperature compensation is that there is no need for a convergence calculation to match the motor model, and an error of an element that would be proportional to the temperature (in an inverter device that performs current control). Since the compensation is performed using a voltage error (this may be a detection error), the reproducibility is high. Therefore, in the second embodiment, stable and highly accurate compensation is possible.

The block diagram which shows 1st Embodiment of this invention. FIG. 3 is a diagram illustrating a specific configuration of a multidimensional table. The block diagram which shows 2nd Embodiment of this invention. The block diagram which shows an example of a motor model. Current command table image explanatory diagram.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Electric motor 12 ... Inverter apparatus 13 ... Multidimensional table 14 ... Speed detector 15 ... Temperature detector 16 ... Current detector 17 ... Deviation device 18 ... Current amplifier 21 ... Motor model

Claims (2)

A device for variable speed control of an electric motor with an inverter device using a torque-current conversion table for converting a torque command and a current command,
A multi-dimensional table in which the temperature information of the motor is added to the torque command and motor speed information as elements of the torque-current conversion table, and the temperature information of the motor is obtained from temperature detection means installed in the motor. Shift control device. A device for variable speed control of an electric motor with an inverter device using a torque-current conversion table for converting a torque command and a current command,
A variable speed control device for a motor, wherein a motor model is installed inside the inverter device, and fluctuation compensation is performed by referring to a torque-current conversion table from temperature information obtained from the model.

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