JPH0744862B2 - Electric motor speed controller - Google Patents

Description

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

[Conventional technology]

As an automatic adjustment method of a control constant in a speed control device for an electric motor, for example, one disclosed in Japanese Patent Laid-Open No. 61-88780 is known. This is because the torque of the electric motor is changed and the rotation speed is changed, the moment of inertia of the mechanical system is obtained from the ratio of the integrated amount of torque at that time and the change width of the rotation speed, and the control constant of the speed adjuster is automatically To be set manually.

[Problems to be Solved by the Invention]

However, this method always performs a test operation to calculate the moment of inertia before actual operation (speed acceleration / deceleration operation).
Is required, and it is difficult to apply to a device such as a winder whose moment of inertia changes during operation.

Therefore, the present invention provides a speed control device capable of automatically and highly accurately setting the control constant of the speed regulator even in a device such as a winder that does not require test operation. The purpose is to provide.

[Means for Solving the Problems]

An observer that estimates the disturbance of the motor from the actual current value, the actual speed value, and the inertial moment setting value of the mechanical system, and a sine wave signal that has a constant amplitude and a frequency sufficiently smaller than the breakpoint frequency of the observer is generated. And a signal generation means to be added to the output of the deceleration controller, and the inertia moment set value and the estimated torque value of the observer when the signal is applied to the output of the speed controller and the inertia moment set value of the observer is changed. And a calculation means for calculating a proportional gain corresponding to the calculated inertia moment value, and speed control is performed based on the proportional gain.

[Operation] An observer that estimates the disturbance of the motor from the actual current value, actual speed value, and inertial moment setting value of the mechanical system is provided in the speed control device of the electric motor, and the drive torque of the electric motor is set to a frequency sufficiently smaller than the break frequency of the observer. Pay attention to the point that the fluctuation of the estimated torque is proportional to the inertia moment setting value of the observer when it is changed as a sine wave signal with, and superimpose a sine wave signal with a constant amplitude and frequency on the output of the speed regulator. While changing the motor torque by
By changing the inertial moment setting value of the observer, the inertial moment value is calculated from the relationship between the estimated torque fluctuation amount and the inertial moment setting value at that time, and a control gain proportional to this is set in the speed controller to control the speed. It can be so.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a circuit diagram showing a concrete example of the observer of FIG. In FIG. 1, 1 is an electric motor, 2 is a static power converter, 3 is a speed detector, 4 is a current detector, 5 is a rectifier, and 6
Is a speed controller (ASR), 7 is a current controller (ACR), 8 is a signal generator, 9 is an observer, and 10 is a control constant calculator.

On the other hand, the observer 9 has a multiplier 9 as shown in FIG.
1, adders 92A and 92B, integrators 93A and 93B, a divider 94, and coefficient units 95A and 95B.

Now, expressing the system of FIG. 1 using a transfer function,
It becomes like the figure. 11 is a speed controller, 12 is a current controller, 13
Is an electric motor, 14 is an adder, K _P and T _I are the proportional gain and time constant of the speed regulator, K and T _C are the proportional gain and time constant of the current regulator, and T _M is the moment of inertia of the electric motor mechanical system. (Starting time constant) is shown. S is a Laplace operator.

By doing so, the transfer function of the observer 9 in FIG. Becomes From the input / output relationship of the adder 92 of FIG. Is obtained, and from the input / output relationship of the integrator 93B and the coefficient unit 95B, Is derived, and τ _M −τ _L = NST _M (4) is obtained from the input / output relationship of the adder 14 in FIG. 3, τ _M = iφ (5 ) Depends on the establishment of the relationship. Note that τ _L is the disturbance torque (load torque) of the electric motor, Is the estimated value, τ _M is the driving torque of the motor, T _M ^* is the set value of T _M , g ₁ and g ₂ are proportional gains, i is the actual current value, φ is the magnetic flux, N is the actual speed value, and Each of the estimated values is shown.

Then, when the drive torque τ _M of the electric motor is changed as a sine wave signal having a frequency sufficiently smaller than the breakpoint frequency of the observer 9, the estimated torque is It can be seen that the fluctuation amount of is proportional to the observer's inertia moment setting value T _M ^{* as} in the following equation (6).

However, τ _M = τ _L + τ _K sin ωt (7) Here, τ _K is the amplitude value, and ω is the angular frequency that is sufficiently smaller than the corner frequency of the observer.

Therefore, in the present invention, the output of the speed regulator has a constant amplitude,
Superimpose a sinusoidal signal with frequency. That is, when a control constant tuning start command is issued during operation of the electric motor, a sine wave having a constant frequency and a constant amplitude is generated from the signal generator 8 and superposed on the output of the speed controller 6.
As a result, the motor torque τ _M changes at the same frequency, and when the set value T _M ^* of the observer 9 differs from the actual moment of the mechanical system, the estimated torque of the observer Fluctuates as shown in FIG. If the moment of inertia of the mechanical system can be predicted, the observer setting value T _M ^* is either larger or smaller than the predicted moment of inertia T
Set to _M1 and T _M2 , and observer change after a certain time Respectively detected. This gives the moment of inertia T
_M is Is required.

On the other hand, the open loop transfer function G (S) of FIG. 3 is expressed by the following equation (9), Since varying the gain K _P is a speed control system when the mechanical system inertia (T _M) is changed, the gain K _P of the speed regulator by T _M obtained by calculation in the previous equation (8) T _M It becomes possible to set in proportion to. Therefore, as the speed regulator 6, a type in which the control constant can be set and changed is used.

When the above processing is performed by using a control device such as a microcomputer, the results are as shown in FIG. 5 and FIG.
Fig. 5 shows the process of applying a sine wave signal of constant amplitude and frequency to the output of the speed regulator, and Fig. 6 shows the moment of inertia of the mechanical system from the inertia moment set value and the fluctuation of the estimated torque value. Then, the process of obtaining and setting the control constant of the speed adjuster will be described. The details are omitted because it is the same as that of FIG. 1 except that these processes are performed by the control device.

The case where the moment of inertia of the mechanical system can be predicted has been described above, but when this cannot be predicted, the procedure is as shown in FIG. The figure is a flow chart for explaining the processing operation when the moment of inertia of the mechanical system cannot be predicted.

That is, as in the case of FIG. 1 or FIG. 5, when the control constant tuning start command is issued during the operation of the electric motor, a sine wave signal having a constant amplitude and a constant frequency is output from the signal generator 8 as a torque command. Value, resulting in the estimated torque of the observer Fluctuates. In this state, the set value T _M ^* of the observer 9 is set to three values T _M1 , T _M2 , T _M3 (T _M1 <T _M2 with a constant difference ΔT _M.
<T _M3 , T _M3 −T _M2 = T _M2 −T _M1 = ΔT _M ), and the variation of the observer after a certain time has passed Detected as (reference), as well as Find the absolute value of the difference between and (see). Since when the difference between both match is either T _M1, T _M2, T _M3 both mechanical or greater than the inertia moment T _M small seeking of seeking T _M by the following equation, (However, n ≠ m, n = 1,2,3, m = 1,2,3) The gain K _P of the speed controller 6 is set by this value T _M (see ,,).

On the other hand, if the difference between the two does not match, the desired moment of inertia exists between T _M1 and T _M2 or between T _M2 and T _M3 , so a new T _M0 smaller than T _M1 or T _M4 larger than T _M3 is set as the observer. Set as the set value T _M ^* , and observer variation after a certain period of time Detected as (reference). Then, calculate the moment of inertia T _M from the above values (see), With this value T _M , the gain K _P of the speed regulator is obtained and set.

〔The invention's effect〕

According to the present invention, a sine wave signal having a constant amplitude and a constant frequency is superimposed on the output of the speed regulator during operation of the electric motor, and the estimated torque of the observer is changed by changing the electric motor drive torque. Obtain the fluctuation amount of the estimated torque when the set value (moment of inertia) is changed,
Accurately measure the moment of the mechanical system from these values,
Since the gain K _P of the speed controller is set based on this value, it is not necessary to perform a test operation before the actual operation to find the moment of inertia, and even if the load is such that the moment of inertia fluctuates during operation, The optimum response can always be controlled.

In addition, although the embodiment shows the case of controlling the DC machine, the same effect can be obtained even when applied to the case of controlling the AC machine.

[Brief description of drawings]

1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a circuit diagram showing a specific example of the observer of FIG. 1, FIG. 3 is a block diagram showing FIG. 1 using a transfer function, and FIG. The figure is a waveform diagram showing the fluctuation waveform in the observer. Fig. 5 is a flow chart showing the process of applying a sine wave signal of constant amplitude and frequency to the output of the speed controller. Fig. 6 is the inertia moment set value and estimated torque value. Is a flow chart showing the process of obtaining the moment of inertia of the mechanical system from the fluctuation amount of the mechanical system, and then obtaining the control constant of the speed regulator, and FIG. 7 is the same as FIG. 6 when the moment of inertia of the mechanical system cannot be predicted. 2 is a flow chart for explaining the processing of FIG. Code description 1,13 ...... Motor, 2 ...... Static power converter, 3 ...... Speed detector, 4 ...... Current detector, 5 ...... Rectifier, 6, 11 ...... Speed controller (ASR), 7, 12 ... Current regulator (ACR), 8 ... Signal generator, 9 ... Observer, 10 ... Control constant calculator,
14,92A, 92B …… Adder, 91 …… Multiplier, 93A, 93B …… Integrator, 94 …… Divider, 95A, 95B …… Coefficient unit.

Claims (2)

[Claims] 1. A speed control device for an electric motor when the speed moment of the electric motor is controlled by using at least a speed adjuster capable of changing a proportional gain, when the moment of inertia of the electric motor mechanical system can be predicted. , (A) An observer that estimates the disturbance torque of the electric motor from the actual current value, the actual speed value, and the inertia moment setting value of the electric motor mechanical system, and (b) has a constant amplitude and is sufficiently smaller than the break frequency of the observer. A signal generating means for generating a sine wave signal having a frequency; and (c) a sine wave signal from the signal generating means, which is expected by the observer in a state where the sine wave signal is added to and superposed on a torque command value which is an output of a speed controller. Of the first and second inertial moment setting values that are both larger (or smaller than both) than the inertial moment. Means, and (d) a means for obtaining a first fluctuation amount, which is a range between the maximum value and the minimum value observed by the observer after setting the first inertia moment set value, and (e) then the observer. The inertia moment set value to be set to the second inertia moment set value from the first inertia moment set value
Switching means for automatically switching to and setting the inertia moment set value of, and (f) the second range of the maximum and minimum values observed by the observer after setting the second inertia moment set value. Means for obtaining a variation, (g) the first and second inertia moment set values,
A means for calculating the inertia moment value of the electric motor mechanical system by the following equation (a) from the calculated first and second fluctuations, and (h) calculating the inertia moment value of the electric motor mechanical system. And a means for calculating a proportional gain of the speed controller corresponding thereto and setting it in the speed controller, and performing speed control based on the proportional gain set in the speed controller. Speed control device. Note T _M = Moment of inertia of motor system T _M1 = First inertia moment setting value T _M2 = Second inertia moment setting value When 2. A speed control device for an electric motor when the speed moment of the electric motor is controlled using at least a speed adjuster capable of changing a proportional gain, when the moment of inertia of the electric machine system is unpredictable. (A) an observer that estimates the disturbance torque of the electric motor from the actual current value, the actual speed value, and the inertia moment setting value of the electric motor mechanical system; and (b) a constant amplitude, which is more than the break frequency of the observer. A signal generating means for generating a sine wave signal having a small frequency; and (c) a sine wave signal from the signal generating means is added to and superposed on a torque command value which is an output of a speed controller, and the observer and the The first with a constant difference between,
Second and third three inertia moment set values (however,
Means for setting any one of the inertia moment set values among (1 <second <third), and (d) the maximum and minimum values observed by the observer after setting the inertia moment set values. A means for obtaining a first variation, which is a range of values, and (e) the inertia moment set value to be set next in the observer is automatically switched to one of the remaining two inertia moment set values. And (f) a means for obtaining a second variation which is a width between the maximum value and the minimum value observed by the observer after setting the inertia moment setting value, and (g) next, Switching means for automatically switching and setting the inertia moment set value to be set in the observer to the other of the remaining two inertia moment set values, and (h) after setting the inertia moment set value, the observer Means for obtaining a third variation that is the width between the maximum value and the minimum value observed by the bar, and (i) the absolute value of the difference between the first variation and the second variation (hereinafter referred to as the 1) and a means for obtaining the absolute value of the difference between the second variation and the third variation (hereinafter referred to as the second absolute value) by calculation, (j) the first absolute value If the two absolute values are compared and they match, the means for obtaining the inertia moment value of the electric motor mechanical system by the following equation (b), and (k) if they do not match, Means for setting any one of a fourth inertia moment setting value smaller than the first inertia moment setting value and a fifth inertia moment setting value larger than the third inertia moment setting value; (L) After setting the inertia moment setting value, the observer Means for obtaining a fourth fluctuation amount, which is the range of the maximum value and the minimum value observed more, and (m) automatically setting the inertia moment setting value to be set in the observer to the other one. Switching means; (n) means for obtaining a fifth variation which is a width between the maximum value and the minimum value observed by the observer after setting the inertia moment set value; and (o) the fourth and the fifth Inertia moment setting value of 5,
Means for calculating the inertia moment value of the electric motor mechanical system from the calculated fourth and fifth fluctuation amounts by the following equation (c) or equation (d): ) Means for calculating a proportional gain of the speed regulator corresponding to the obtained inertia moment value of the electric motor mechanical system and setting the proportional gain in the speed regulator, and a proportional gain set in the speed regulator. A speed control device for an electric motor, characterized in that speed control is performed based on. Note T _M = Motor system inertia moment value T _M1 = First inertia moment setting value T _M2 = Second inertia moment setting value T _M3 = Third inertia moment setting value When (However, n ≠ m, n = 1,2,3, m = 1,2,3) T _M0 = Fourth moment of inertia set value T _M4 = Fifth moment of inertia set value When