JP2997278B2 - Motor control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a motor control device that controls a motor speed in a main loop while controlling an armature current of a motor coupled to a load via a shaft.

[Prior art]

Conventionally, as a control device of this type, the present applicant has provided a delay element to which a signal proportional to the shaft torque is input, and adds the output of the delay element and the output of the speed adjustment loop to the input of the current adjustment loop. A method of controlling shaft torsional vibration by performing control as described above has been proposed (Japanese Patent Application No. 63-83130).

[Problems to be solved by the invention]

The proposed control device is based on the control of suppressing the shaft torsional vibration without a gear, and the effect of the control device on the control of the shaft torsional vibration with a gear is not clear. Furthermore, when the parameters of the torsional vibration system are unclear or fluctuate, the response of the speed adjustment loop cannot be kept optimal. Therefore, the present invention suppresses the vibration even when the control target is a non-linear torsional vibration system with a gear interposed, and performs a new adjustment even when the parameters of the torsional vibration system are unclear or fluctuate. An object of the present invention is to provide a control device for an electric motor that can maintain an optimum response of a speed adjustment loop without performing the operation.

[Means for Solving the Problems]

In order to solve such a problem, the present invention provides a reference model which receives a deviation between a motor torque and a compensation output and outputs a signal corresponding to a motor speed, and a difference between an output of the reference model and an actual speed value. And a compensation gain element for generating a compensation output by multiplying the reference model by a predetermined value.The reference model is provided with a motor start time constant element that gives a deviation between the motor torque and the compensation output, and an output signal of the motor start time constant element. And a delay operator for outputting a signal corresponding to the motor speed, wherein the current control loop calculates an addition amount obtained by adding a compensation output generated from the compensation gain element and an output of the speed regulator in the speed regulation loop. The feature is to give to.

[Operation]

According to the present invention, the difference between the output of the model and the control target is multiplied by a predetermined value, and is added to the speed adjustment loop of the control target as a compensation output, so that the model becomes a new control target even when the model and the control target are different. Therefore, even when the controlled object is a non-linear torsional vibration system with a gear interposed, the vibration can be suppressed. Further, according to the present invention, even when a parameter to be controlled is unclear or fluctuates, the speed adjustment loop can be maintained at an optimum response without performing new adjustment. This will be described in more detail based on the principle of the present invention. FIG. 1 is a principle diagram for explaining the principle of the present invention. In FIG. 1, 51 is an input element, 52 is a controlled object, 53 is a compensator, 531 is a reference model for the controlled object, 5
32 is a compensation gain element having a compensation gain L, and 533 is an adjustment gain element having an adjustment gain K. It is assumed that the input element 51 can be approximately set to 1 and that the disturbance D (s) = 0. When the input R (s) is given as U (s) to the control target 52 and the model 53, an output Y (s) of the control target 52 and an output W (s) of the model 531 are generated. When the control target 52 and the model 531 are different, their outputs are also different, but the compensation output C (s) obtained by multiplying the deviation by the compensation gain element 532 by a predetermined factor is further multiplied by the adjustment gain element 533 to obtain a compensator. An output of 53 is added to the input R (s). On the other hand, the compensation output C (s) is subtracted from the amount of U (s) to adjust the amount of U (s) input to the model 531. Thus, the input R (s) and the output Y (s)
The relationship is When L → ∞ and K = 1, Thus, the relationship between the input R (s) and the output Y (s) becomes a model P _m (s) regardless of the control target P (s). on the other hand,
The relationship between the disturbance D (s) and the output Y (s) is as follows: input R (s) = 0.
After all, When L → ∞ and K = 1, Thus, the output Y (s) is not affected by the disturbance D (s). Now, assume that the control target P (s) is represented in FIG.
In FIG. 2, reference numeral 61 denotes a block indicating a load,
S is Laplace operator in its transfer relationship 1 / _S T _L, T _L is the integration time of the integrator 61 corresponding to the moment of inertia of the load. Reference numerals 63 and 62 denote blocks indicating axes, 62 denotes a dead zone formed by gears, and 63 denotes an integrator whose output θ indicates the angle between the blades of the gear. 64 is a block showing the motor, and _Tm is the integration time of the integrator 64 corresponding to the moment of inertia of the motor. In these blocks 61,62,63,64,
It constitutes a shaft torsional vibration system including non-linear elements due to gears. Also, τ _M is the motor torque, _nm is the motor speed,
τ _c indicates shaft torque, τ _L indicates load torque, and n _L indicates load speed. FIG. 3 shows a model for the controlled object, where T _m ′ is the integration time of the integrator 65. Thus, when the control object P (s) is represented in FIG. 2 and the model P _m (s) is represented in FIG. 3, the gear of FIG. 2 is interposed as shown in equation (2). The shaft torsional vibration system is replaced by an integrator 65 shown in FIG. That is, even when the parameter to be controlled is unclear or fluctuates, the speed adjustment loop can be maintained at an optimum response without performing new adjustment, and vibration can be suppressed.

【Example】

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 4 is a block diagram showing one embodiment of the present invention.
In FIG. 4, 1 is a thyristor Leonard speed control device, 2 is a compensator, 3 is a thyristor converter, 4 is a current detector, 5 is a load, 6 is an elastic shaft, 7 is a DC motor, and 8 is a speed detector. , 9 are gears. In the thyristor Leonard speed control device 1 for controlling the thyristor converter 3 for supplying power to the armature circuit of the DC motor 7, 11 is a speed regulator (ASR), and 12 is a current regulator (AC).
R) and 13 are pulse generators. The speed of the motor 7 is detected by the speed detector 8 and adjusted by the speed adjuster 11 so as to be equal to the set speed value n ^* . The output of the speed controller 11 is given as _a current command i _a ^* of the current controller 12, and the armature current of the electric motor 7 is controlled by the thyristor converter 3 via the pulse generator 13. On the other hand, a compensator 2 that outputs a compensation signal of a shaft torsional vibration system formed by the electric motor 7, the elastic shaft 6, the load 5, and the gear 9
, 20 is a motor model, 21 and 25 are field simulation elements that provide a gain φ or 1 / φ corresponding to the field magnetic flux φ, 22
Is a motor start time constant element having a sampling period t as a function, 23 is an addition element, 24 is a delay operator, 26 is a proportional gain element, and 27 is an adjustment gain element. Elements 22, 23 and 24 correspond to the integrator 65 of FIG. 3, and are here digitally constructed. Also, C (i) is the compensation output, τ _M (i) is the motor torque, i _C (i) is the current conversion value of the compensation output, i _a (i) is the motor current, n _m (i) is an electric circuit speed , W (i) are the outputs of the motor model. Note that i in parentheses indicates the i-th sampling. Motor speed n _m (i) to be controlled and model output W
Compensation output C obtained by multiplying the difference from (i) by a proportional gain
When added to the output of the regulator 11 multiplied by the adjustment gain 27 to the current conversion value i _c of (i) (i) entering into the current regulator 12 as a current command i _a ^*, current command i _a ^* and the electric motor Since the transfer function between the current i _a can be approximately i _a ^* / i _a = 1, the first
It is equivalent to the figure. That is, it is possible to suppress the torsional vibration caused by the gear 9 and to perform no new adjustment even when the moment of inertia of the electric motor 7 or the load 5 or the spring constant of the elastic shaft 6 is unclear or fluctuates. The speed control loop can be kept at an optimum response. Further, as shown in equation (4), the motor speed with respect to the disturbance
Since the sensitivity of _nm can be reduced, torsional vibration can be suppressed without impairing the response of the speed control system.
The speed control loop can be maintained at an optimum response even to a change in the parameter of the control target. The present invention is particularly effective when applied to a shaft torsional vibration system in which a gear is interposed. However, as a control device, the present invention is also applicable to a shaft torsion system without a gear and a system having no shaft torsional vibration. In addition, the present invention can be applied to a system in which the parameter of the control target fluctuates.

【The invention's effect】

According to the present invention, it is possible to maintain good output response even for a vibration system in which gears are combined in many stages or a system in which a control object changes with time.

[Brief description of the drawings]

FIG. 1 is a principle diagram for explaining the principle of the present invention, FIG. 2 is a block diagram of an object to be controlled in FIG. 1, and FIG.
FIG. 4 is a block diagram of a model in the compensator in the figure, and FIG. 4 is a configuration diagram showing an embodiment of the present invention. 51 ... input element, 52 ... controlled object, 53 ... compensator, 531
…… model, 532 …… compensation gain element, 533 …… adjustment gain element.

Claims (1)

(57) [Claims] In a motor control device having a current control loop for controlling a motor current as a minor loop with respect to a speed adjustment loop for controlling a motor speed, a deviation between the motor torque and a compensation output is input and corresponds to the motor speed. A reference model that outputs a signal, and a compensation gain element that generates the compensation output by multiplying a difference between the output of the reference model and the actual speed value by a predetermined number.The reference model includes the motor torque and the compensation output. And a delay operator to which an output signal of the motor start time constant element is given and outputs a signal corresponding to the motor speed, and a compensation generated from the compensation gain element. An electric motor characterized in that an addition amount obtained by adding an output and an output of a speed controller in the speed control loop is given to the current control loop. The control device.