JP2005204397A - Motor control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a work to advance smoothly without necessity of setting a control parameter by a manual input by an operator since a model selection can be performed even in a motor using a resolver as a rotor position detecting means and to enable an increase in the number of the models and an increase in management/service costs to be decreased sharply since the motor and an amplifier are not necessarily made to correspond one-on-one. <P>SOLUTION: A motor control system includes: a servo motor 1 which uses the resolver as a means for detecting a rotor position; a current detector 3 having a servo amplifier for controlling the servo motor from rotor position information detected by the resolver 2 to detect the phase current of the motor; a pulse generator 7 for forming an energization timing signal to the motor; a motor constant estimator 8 for presuming the motor characteristics of the servo motor; a parameter setter 9 for calculating a control parameter from the presumed motor constant to set the control parameter; and a motor controller for controlling the servo motor based on the set control parameter. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a motor control system using a resolver as a rotor position detection device of a motor in a servo motor control device including a motor and an amplifier that require high-precision positioning control and speed tracking control.

In the fields of industrial robots and semiconductor devices, highly accurate positioning and speed following performance are required. A rotary encoder is used as a position detector for the servo motor. Rotary encoders are roughly classified into incremental encoders and absolute encoders. The incremental encoder includes A and B phase signals having a phase difference of 90 degrees, a reference Z signal of 1 pulse per rotation, and commutation signals U, V, and W for switching the energized phase of the rotor. The absolute encoder is an encoder that can recognize the absolute position within one rotation immediately after the power is turned on, and is rapidly spreading. In recent years, as shown in FIG. 11, in addition to such a position detection function, the rotary encoder is required to control the motor such as the motor resistance, inductance, back electromotive voltage, and rotary encoder type in order to identify the motor. Some of them have a memory that stores constants. (For example, see Patent Document 1)
An example of a motor control system using a conventional rotary encoder is shown in FIG. An example of a motor control system using a conventional resolver is shown in FIG. An example of a conventional resolver configuration is shown in FIG. FIG. 13A is an explanatory diagram showing an outline of the configuration of the resolver, and FIG. 13B is an explanatory diagram of a waveform of a signal output from the resolver.

  This is because when the motor and amplifier are connected and the power is turned on, the information necessary for motor control can be sent from the memory installed in the rotary encoder to the amplifier and the initial setting of the amplifier can be made. There is no need to change the control parameters of the amplifier.

One resolver is configured as shown in FIG. 13, which is a one-phase excitation, two-phase output type resolver. There are other two-phase excitation and two-phase output types, but the principle is the same. When a sine wave voltage is applied to the excitation phase of FIG. 13, a sine wave and a cosine wave are output to the output phase. Since the inductance changes as the rotor rotates, the amplitudes of the output sine wave and cosine wave change, and the rotor position is determined from the change in amplitude. As shown in FIG. 13, the resolver is composed of a rotor, a stator, and a winding made of an iron plate material such as a silicon steel plate, and is therefore very robust, and it is not necessary to mount electronic components on the resolver. It is widely used in electric vehicles and high-speed rotation applications that require high reliability under high temperature and high humidity conditions.
JP-A-7-75364

  However, resolvers with excellent environmental resistance and reliability do not have a memory for storing parameters required for motor control, unlike rotary encoders, so if the combination of motor and amplifier changes, the operator must manually input it. The control parameter must be set with. As a matter of course, in the configuration in which the control parameter storage memory is mounted on the motor, it is difficult to set the control parameter in a situation where the working environment is not favorable. In addition, when the motor and the amplifier are made to correspond one-to-one, there is a problem that the number of models increases and the management / service cost increases. As described above, the conventional motor control system has a configuration in which a problem is easily caused in workability regarding the setting of the control parameter.

  In order to solve the above problems, a motor control system of the present invention comprises a servo motor that uses a resolver as means for detecting a rotor position, and a servo amplifier that controls the servo motor from rotor position information detected by the resolver. A current detector for detecting the phase current of the motor, a pulse generator for creating a timing signal for energizing the motor, a motor constant estimator for estimating the motor characteristics of the servo motor, and a control parameter or control parameter group from the estimated motor constant And a parameter setting unit that sets the control parameter or control parameter group, and a motor controller that controls the servo motor based on the set control parameter or control parameter group.

  The above will be described in more detail.

The motor control system of the first invention is
A servo motor,
A resolver as means for detecting rotor position information of the servo motor;
A servo amplifier that controls the servo motor from rotor position information detected by the resolver;
A current detector for detecting a phase current of the servo motor;
A pulse generator for creating an energization timing signal to the servo motor;
A motor constant estimator for estimating the motor characteristics of the servo motor;
A parameter setter for obtaining a control parameter by calculating based on the estimated motor constant and setting the control parameter;
A motor controller that sets the control parameter and controls the servo motor based on the control parameter.

The motor control system of the second invention is
A servo motor,
A resolver as means for detecting rotor position information of the servo motor;
A servo amplifier that controls the servo motor from rotor position information detected by the resolver;
A current detector for detecting a phase current of the servo motor;
A pulse generator for creating an energization timing signal to the servo motor;
A motor constant estimator for estimating the motor characteristics of the servo motor;
A parameter MAP setter for obtaining a control parameter or control parameter group by calculating based on the estimated motor constant and setting the control parameter or control parameter group;
A motor controller that sets the control parameter or the control parameter group and controls the servomotor based on the control parameter or the control parameter group.

The motor control system of the third invention is
A servo motor,
A servo motor having a resolver as means for detecting the rotor position of the servo motor; and a servo amplifier for controlling the servo motor from rotor position information detected by the resolver;
A current detector for detecting a phase current of the servo motor;
A pulse generator for creating an energization timing signal to the servo motor;
A motor constant estimator for estimating a motor constant of the servo motor;
A parameter MAP comprising another motor constant group (motor constant group B) corresponding to the motor constant and a control parameter group corresponding to each motor constant of the other motor constant group (motor constant group B);
A parameter MAP selector for selecting a control parameter group corresponding to the motor constant by the motor constant estimator from the parameter MAP;
A motor controller that controls the servo motor based on the control parameter group selected by the parameter MAP selector.

The motor control system of the fourth invention is:
A resolver as means for detecting rotor position information of a controlled servo motor;
A servo amplifier that controls the controlled servo motor from rotor position information detected by the resolver;
A current detector for detecting a phase current of the controlled servo motor;
A pulse generator for creating an energization timing signal to the controlled servo motor;
A motor constant estimator for estimating the motor characteristics of the controlled servo motor;
A parameter setter for obtaining a control parameter by calculating based on the estimated motor constant and setting the control parameter;
A motor controller for controlling the controlled servo motor based on the set control parameter.

The motor control system of the fifth invention is
A resolver as means for detecting rotor position information of a controlled servo motor;
A servo amplifier that controls the controlled servo motor from rotor position information detected by the resolver;
A current detector for detecting a phase current of the controlled servo motor;
A pulse generator for creating an energization timing signal to the controlled servo motor;
A motor constant estimator for estimating the motor characteristics of the controlled servo motor;
A parameter MAP setting device that calculates based on the estimated motor constant to obtain a control parameter or control parameter group and sets the control parameter or control parameter group;
A motor controller for controlling the controlled servo motor based on the set control parameter or control parameter group.

  The motor control system according to a sixth aspect of the present invention is the motor control system according to any one of the first to fifth aspects, wherein the energization timing signal output from the pulse generator to the motor short-circuits at least two phases of the motor. In this configuration, the constant time is turned on and the constant time is turned off.

  A motor control system according to a seventh aspect of the present invention has a configuration in which, in the first to sixth aspects of the invention, the time for turning on is increased when the reference current value is not reached.

  A motor control system according to an eighth aspect of the present invention is a configuration in which, in the first to seventh aspects of the invention, the method of increasing the ON time is increased from the initial time by the ratio between the reference current value and the detected current value.

  According to a ninth aspect of the present invention, in the first to eighth aspects of the invention, the energization timing signal output from the pulse generator to the motor is set so as to short-circuit the windings of at least two phases of the motor. In this configuration, a voltage is applied to the motor only for a period of time, and the motor constant is estimated from the detected phase current of the motor.

  A motor control system according to a tenth aspect of the invention is a configuration in which, in the first to ninth aspects of the invention, the voltage application to the motor uses a signal that repeats ON / OFF.

  A motor control system according to an eleventh aspect of the invention is a configuration in which, in the first to tenth aspects of the invention, the set time is 100 μs or more and 100 ms or less.

  The motor control system of the present invention estimated a current detector that detects a phase current of the motor, a pulse generator that generates a current-carrying timing signal for the motor, a motor constant estimator that estimates the motor characteristics of the servo motor, and A parameter setter that calculates a control parameter from a motor constant and sets the control parameter, and a motor controller that controls the servo motor based on the set control parameter are provided. This makes it possible to select a model even in a motor that uses a resolver as the rotor position detecting means, and it is possible for the operator to proceed smoothly without having to manually set control parameters. . In addition, since there is no need for one-to-one correspondence between motors and amplifiers, it is possible to drastically reduce the increase in the number of models and the increase in management and service costs. Thus, the motor control system of the present invention can provide a configuration that can further improve workability with respect to setting of control parameters.

  In addition, the motor control system of the present invention includes a constant estimator and a parameter MAP selector configured to select a corresponding control parameter or control parameter group from the control parameter or control parameter group using the estimated motor constant. A large and detailed model selection is possible.

  In addition, the motor control system of the present invention is configured such that the energization timing signal output from the pulse generator to the motor short-circuits the windings for at least two phases of the motor for a certain period of time. By repeatedly turning OFF, it is possible to prevent the amplifier and the motor from being destroyed by limiting the current at the time of detecting the motor phase current.

  Further, the motor control system of the present invention can increase the motor constant estimation accuracy by increasing the ON time when the detected motor phase current does not reach the reference current value.

  Further, in the motor control system of the present invention, the time required for motor constant estimation can be shortened by increasing the ON time from the initial time by the ratio of the reference current value and the detected current value. .

  In addition, the motor control system of the present invention detects by applying a voltage to the motor for a set time so that the energization timing signal output from the pulse generator to the motor shorts the windings for at least two phases of the motor. Various motor models can be estimated by estimating the motor constant from the motor phase current.

  In addition, the motor control system of the present invention is preferably configured to use a signal that repeats ON / OFF for voltage application to the motor.

  In the motor control system of the present invention, it is preferable that the set time is 100 μs or more and 100 ms or less.

(Embodiment 1)
The basic configuration of the motor control system of the first embodiment will be described with reference to FIG.

  First, a basic configuration of a servo motor and an amplifier using a resolver as a position detector will be described. A motor device 30 includes a servo motor 1 and a resolver 2. As the servo motor 1, a three-phase AC brushless motor is often used in terms of efficiency, vibration and noise. The resolver 2 detects the rotor position of the motor. By applying a sine wave excitation voltage using the difference in inductance between the resolver rotor position, the amplitude of the two-phase output signal of the sine wave and cosine wave is obtained. Output the modulated waveform.

  The R / D converter 11 outputs position information as a 10-bit or 12-bit digital signal based on the sine wave and cosine wave signals output from the resolver 2. Recently, it has been made into one chip IC. The current detector 3 detects a current flowing through the phase winding of the motor, and a CT or a shunt resistor is usually used, and converts the current value into a voltage value and outputs it. The A / D converter 10 converts the voltage value from the current detector 4 into a digital signal so that the microcomputer can recognize it. The power converter 4 is used to separate phases to be supplied to the motor. In the case of a three-phase motor, the power converter 4 includes six power elements and six diodes as shown in FIG.

  The position / speed command 16 is a command for the rotor rotation angle and the motor rotation speed given from the outside to the motor. For the position command, for example, in the case of a pulse command value, the number of pulses corresponding to one rotation of the rotor is set as a set value, and the number of pulses to be input determines how many times the rotor is rotated. In the speed command, for example, in the case of an analog command, the motor rotation speed and the command voltage value are set as set values, and the motor is rotated by the command value by giving the speed command voltage. The command value I / F device 6 converts the signal given from the position / speed command 16 into a digital signal that can be recognized by a microcomputer.

  Based on the command value given from the position / speed command 16, the motor controller 5 receives the motor rotor position information given from the R / D converter 11 and the motor phase current information given from the A / D converter 11. Therefore, it functions to control the timing of energizing each phase of the motor and outputs a signal to the power converter 4. The above is the basic configuration of the motor and the amplifier.

  Next, the motor control system according to the first embodiment will be described with reference to FIGS. 1, 3, 4 and 7. FIG.

  A control parameter setting block 1 is indicated by reference numeral 31 and outputs control parameters necessary for motor control to the controller 5. The control parameter setting block 1 (reference numeral 31) includes a pulse generator 7, a motor constant estimator 8, and a parameter setter 9. The pulse generator 7 gives a control signal necessary for motor constant estimation to the power converter 4 and gives the control information to the motor constant estimator 8. As shown in FIG. 4, the control signal gives a PWM signal (Pulse Width Modulation) that turns on the power element 22c and turns on / off the power element 22a. When the control signal is given in this way, the motor winding is in a state in which the U-V phase is short-circuited as shown in FIG. At this time, the current 25 of the motor U-phase winding 17 is as shown in FIG. The motor constant estimator 8 estimates the motor constant from the motor characteristic value (motor current, etc.) and the control information of the motor as follows. Here, assuming that the main power supply 17 is Vdc and the duty (duty ratio) of the PWM output from the pulse generator 7 is α%, the resistance Ru of the motor U-phase winding 17 of the motor constants is expressed by Equation 1.

  Ru = (Vdc · α / 100) / Iave · 1/2 [Ω] (Equation 1)

  The parameter setting unit 9 sets a control parameter from the motor constant obtained by Equation 1. The winding resistance of the motor can be classified as shown in Table 1 according to the motor capacity.

  Since the capacity of the motor can be estimated from this, the parameter selector 9 can provide the motor controller 5 with a control parameter or a control parameter group necessary for motor control.

  The α of the PWM duty (duty ratio) output from the pulse generator 7 is set to 0.4 to 4% or less in accordance with the amplifier capacity. For example, α is 0.4% at 30 W, and α is 4% or less at 750 W. Other capacitors also change the value of α in inverse proportion to the instantaneous maximum current value of the amplifier. Usually, in the servo motor, the instantaneous maximum torque is generally 500% of the rated torque. The power element is selected so as to allow current flowing when 500% torque is generated. For example, if the amplifier capacity is 30W, α is 0.4%, and Vdc is 280V, when a 30W motor is connected, the motor current is 2.8A, which is less than the instantaneous maximum current that the amplifier can tolerate. The model of the motor can be estimated without destruction.

  When the motor phase resistance is large, the PWM duty (duty ratio) α can be set large. For example, if the phase resistance of the motor is doubled for all capacities, the value of α may be doubled.

  Moreover, although it is the short circuit method of a motor winding, you may short-circuit a U-VW phase like FIG. The operation of the power element in this case is as shown in FIG.

  4 and 6, only the power element 22a is PWMed as shown in FIGS. 4 and 6, but the power element 22e or both of the power elements 22e and 22f may be PWM, and conversely the power element 22a. The power element 22e or the power elements 22e and 22f may be PWMed.

(Embodiment 2)
A second embodiment is shown in FIG. Differences from the first embodiment will be described. The parameter MAP selector (parameter map selector) 12 stores control parameters or control parameter groups necessary for motor control. The motor constant group (motor constant group B), control parameters, and / or control parameter groups stored in Table 2 are examples. The value of the phase resistance estimated by the motor constant estimator 8 is input to the parameter MAP selector (parameter map selector) 12, and the corresponding phase resistance is retrieved from Table 2. The control parameter or control parameter group for each selected motor model is transmitted to the motor controller 5. The control parameter setting block 2 is indicated by reference numeral 32.

  Further, Table 2 is stored in the motor controller 5, and the parameter MAP selector (parameter map selector) 12 stores only the phase resistance and the motor model, and transmits the motor model number to the motor controller 5. Gives the same result.

  In addition, the motor constant group (motor constant group B) in Table 2 indicates a numerical group described in the column of phase resistance. Further, the control parameter or / and control parameter group refers to a numerical group described in the columns of torque constant, induced voltage constant, phase inductance, rated rotational speed, rotor inertia, resolver resolution, and control gain.

(Embodiment 3)
A third embodiment is shown in FIG. Differences from the first embodiment and the second embodiment will be described. The duty α of the PWM signal output from the pulse generator 7 is set for each amplifier capacity, but the setting range is set to 0. 0 in consideration of the case where a motor having a small phase resistance is connected. A relatively small value of several percent to several percent is set. When a motor having a large phase resistance is connected, the motor phase current decreases and the detection error increases. As shown in FIG. 8, the PWM duty is increased when the motor phase current is below the reference value. The motor constant is estimated using the value when the motor phase current exceeds the reference value. The method of increasing the PWM duty may be increased by the set% value as shown in FIG.

  Further, in order to shorten the time for estimating the motor constant, the duty may be increased from the ratio between the reference current value and the detected current value.

(Embodiment 4)
A motor control system according to Embodiment 4 will be described with reference to FIG. The PWM signal from the pulse generator 7 continues to be ON for Δt1 as shown in FIG. The motor model is estimated by detecting the motor phase current Ip in this case and calculating the phase inductance L of the motor. The phase inductance L can be obtained by Equation 2. Since the obtained phase inductance L differs depending on the motor model as shown in Table 2, the motor can be selected.

  L = 1 / Ia · ∫ (Vdc−R · Iu) dt (Formula 2)

  In FIG. 9, the signal is continuously turned on during the period Δt1, but as shown in FIG. 10, the PWM signal may be applied during the period Δt2.

  In addition, the duty α in this case is configured as shown in the second and third embodiments, so that the phase inductance L can be estimated accurately and safely.

  Further, although the measurement periods Δt1 and Δt2 are set, since the time constant of the motor is usually several ms to several hundreds ms, the measurement period is preferably 100 μs to 100 ms.

  Further, by creating a parameter MAP that combines the phase resistance R and the phase inductance L and selecting a motor model, it is possible to select more and more detailed models.

  Note that the resolver and the servo motor described in the first to fourth embodiments may be either an integral component or a component that combines separate components. For example, a structure in which a resolver as a separate component is attached to a part of the output shaft of the controlled servo motor may be used. Further, an integral structure including the resolver structure may be used in the servo motor structure.

  The motor control system according to the present invention has a configuration capable of further improving workability with respect to setting of control parameters, and is useful as a motor control system using a resolver as a rotor position detection device of a motor.

Explanatory drawing of the block of the motor control system of Embodiment 1 Explanatory drawing of the block of the motor control system of Embodiment 2. Explanatory drawing which shows the motor short circuit state of Embodiment 1. Explanatory drawing of the power converter at the time of the motor short circuit state of Embodiment 1 Explanatory drawing which shows the motor short circuit state of Embodiment 1. Explanatory drawing of the power converter at the time of the motor short circuit state of Embodiment 1 Explanatory diagram of motor phase current waveform and PWM signal waveform of the first embodiment Explanatory diagram of motor phase current waveform and PWM signal waveform of the third embodiment Explanatory drawing which shows the motor short circuit state of Embodiment 4. Explanatory diagram of motor phase current waveform and PWM signal waveform of the fourth embodiment Block diagram of a motor control system using a conventional rotary encoder Block diagram of a motor control system using a conventional resolver An explanatory view showing the structure of a conventional resolver, (a) an explanatory view showing an outline of the resolver structure, and (b) an explanatory view of a waveform of a signal output from the resolver

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Servo motor 2 Resolver 3 Current detector 4 Power converter 5 Motor controller 6 Command I / F device 7 Pulse generator 8 Motor constant estimator 9 Parameter setter 10 A / D converter 11 R / D converter 12 Parameter MAP selector (parameter map selector)
13 Rotary encoder 14 Parameter I / F device 15 Memory 16 Position command, speed command 17 Main power supply 18 Power switch 19 U-phase winding 20 V-phase winding 21 W-phase winding 22a, 22b, 22c, 22d, 22e, 22f Power Elements 23a, 23b, 23c, 23d, 23e, 23f Flywheel diode 24 PWM signal 25 Motor phase current 26 Excitation phase 27 Sine wave output phase 28 Cosine wave output phase 29 Resolver rotor 30 Motor device 31 Control parameter setting block 1
32 Control parameter setting block 2
33 PWM Duty (PWM duty)
34 Reference current value

Claims (11)

A servo motor,
A resolver as means for detecting rotor position information of the servo motor;
A servo amplifier that controls the servo motor from rotor position information detected by the resolver;
A current detector for detecting a phase current of the servo motor;
A pulse generator for creating an energization timing signal to the servo motor;
A motor constant estimator for estimating the motor characteristics of the servo motor;
A parameter setter for obtaining a control parameter by calculating based on the estimated motor constant and setting the control parameter;
A motor control system comprising: a motor controller that sets the control parameter and controls the servo motor based on the control parameter. A servo motor,
A resolver as means for detecting rotor position information of the servo motor;
A servo amplifier that controls the servo motor from rotor position information detected by the resolver;
A current detector for detecting a phase current of the servo motor;
A pulse generator for creating an energization timing signal to the servo motor;
A motor constant estimator for estimating the motor characteristics of the servo motor;
A parameter MAP setter for obtaining a control parameter or control parameter group by calculating based on the estimated motor constant and setting the control parameter or control parameter group;
A motor control system comprising: a motor controller that sets the control parameter or the control parameter group and controls the servo motor based on the control parameter or the control parameter group. A servo motor,
A servo motor having a resolver as means for detecting the rotor position of the servo motor; and a servo amplifier for controlling the servo motor from rotor position information detected by the resolver;
A current detector for detecting a phase current of the servo motor;
A pulse generator for creating an energization timing signal to the servo motor;
A motor constant estimator for estimating a motor constant of the servo motor;
A parameter MAP comprising another motor constant group corresponding to the motor constant and a control parameter group corresponding to each motor constant of the other motor constant group;
A parameter MAP selector for selecting a control parameter group corresponding to the motor constant by the motor constant estimator from the parameter MAP;
A motor control system comprising: a motor controller that controls the servo motor based on the control parameter group selected by the parameter MAP selector. A resolver as means for detecting rotor position information of a controlled servo motor;
A servo amplifier that controls the controlled servo motor from rotor position information detected by the resolver;
A current detector for detecting a phase current of the controlled servo motor;
A pulse generator for creating an energization timing signal to the controlled servo motor;
A motor constant estimator for estimating the motor characteristics of the controlled servo motor;
A parameter setter for obtaining a control parameter by calculating based on the estimated motor constant and setting the control parameter;
A motor control system comprising: a motor controller that controls the controlled servo motor based on the set control parameter. A resolver as means for detecting rotor position information of a controlled servo motor;
A servo amplifier that controls the controlled servo motor from rotor position information detected by the resolver;
A current detector for detecting a phase current of the controlled servo motor;
A pulse generator for creating an energization timing signal to the controlled servo motor;
A motor constant estimator for estimating the motor characteristics of the controlled servo motor;
A parameter MAP setter for obtaining a control parameter or control parameter group by calculating based on the estimated motor constant and setting the control parameter or control parameter group;
A motor control system comprising: a motor controller that controls the controlled servo motor based on the set control parameter or control parameter group. The energization timing signal output from the pulse generator to the motor is repeatedly turned on for a certain period and turned off for a certain period so as to short-circuit the windings of at least two phases of the motor. The motor control system according to any one of claims 1 to 5. The motor control system according to any one of claims 1 to 6, wherein a time for turning on is increased when the reference current value is not reached. The motor control system according to any one of claims 1 to 7, wherein the ON time is increased from the initial time by a ratio of the reference current value and the detected current value. The energization timing signal output from the pulse generator to the motor applies a voltage to the motor for the set time so that the windings for at least two phases of the motor are short-circuited, and the motor constant is estimated from the detected phase current of the motor The motor control system according to any one of claims 1 to 8, wherein: The motor control system according to any one of claims 1 to 9, wherein the voltage application to the motor is a signal in which ON / OFF is repeated. The motor control system according to any one of claims 1 to 10, wherein the set time is 100 µs or more and 100 ms or less.

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