JPH0767320B2 - Control gain adjustment method for vector control type induction motor drive - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for automatically adjusting a control gain of a vector control type induction motor drive device using an adaptive observer of an induction motor (induction motor).

[Conventional technology]

As an automatic adjusting method for this type of vector control type induction motor driving device, conventionally, for example, a speed controller 10 as shown in FIG.
1, magnetic flux setting device 102, torque current gain (L ₂ / M) 103, exciting current gain (1 / M) 104, control device 10 including vector control unit 105 and secondary resistance calculation unit 106, power conversion Vessel 4,
In the vector control type induction motor driving device including the induction motor 5 and the speed detector 6, the induction motor required for calculating the slip angular frequency command ω _S ^* and the primary angular frequency command ω ^* according to the torque command Next resistance estimated value R ₂ ^*
From the primary voltage V _U , V _V , V _W and the primary current i _U , i _W supplied by the power converter to the induction motor and the speed ω _r , the secondary resistance calculation means 106.
Was calculated and set.

[Problems to be Solved by the Invention]

However, in such a method, vector control means, power converter gain error, torque component current gain (L ₂ / M), exciting current gain (1 / M) setting error, or voltage, current, and speed detection error If there is an estimation error of the secondary resistance estimated value R ₂ ^* due to the above, there arises a problem that it becomes impossible to output the torque as instructed by the set secondary magnetic flux.

Therefore, the present invention does not depend on the vector control means, the control error of the power converter or the measurement error of the induction machine equivalent circuit constant,
An object of the present invention is to provide a control gain adjusting method for a vector control type induction motor drive device capable of adjusting an exciting current gain, a torque component current gain, and a slip adjusting gain so that an accurate output torque can be obtained with a set secondary magnetic flux. To do.

[Means for Solving the Problems]

In order to achieve the above object, in the present invention, a vector control type motor drive device for controlling an induction motor by dividing its current into an exciting current component parallel to the secondary magnetic flux and a torque current component orthogonal thereto ( Drive device) for calculating a secondary magnetic flux from a detected primary current value and a detected primary voltage value
The induction circuit equivalent circuit constant is adjusted so that the calculation results of the magnetic flux calculation unit, the second magnetic flux calculation unit that calculates the secondary magnetic flux from the detected primary current value and the rotation speed, and the calculation results of the first and second magnetic flux calculation units match. An adaptive observer including a controller, a torque calculator that estimates and calculates an output torque from the output of the first magnetic flux calculator and the detected primary current, and a torque setter that generates an output torque command when adjusting the control gain. The secondary magnetic flux output from the adaptive observer, the equivalent circuit constant of the induction motor, the output torque, and the torque command output from the torque setter are input,
Excitation current gain, which is the reciprocal of mutual inductance, and
A torque current gain, which is a value obtained by dividing the secondary inductance by the mutual inductance, and a computing unit that computes a slip adjustment gain, which is a secondary resistance, are provided, and the gain computing unit is the adaptive observer during control gain adjustment. The excitation current gain, torque current gain, and slip adjustment gain of the drive device are set by using the induction motor equivalent circuit constant output from the motor, and the secondary magnetic flux estimated by the adaptive observer is used for excitation during no-load operation. After adjusting the current gain, adjust the current gain and slip adjustment gain for the torque so that the deviation between the output torque and the secondary magnetic flux estimated by the adaptive observer and its command value during acceleration / deceleration operation are within the allowable values. .

[Action]

By doing as described above, the control gain can be automatically adjusted regardless of the control error and the gain setting error of the vector control unit and the power converter.

〔Example〕

FIG. 1 is a flow chart showing a second embodiment of the present invention.
Fig. 3 is a block diagram showing the entire system to which the present invention is applied, Fig. 3 is a block diagram showing a concrete example of the adaptive observer of Fig. 2, and Fig. 4 is a measurement of output torque and secondary magnetic flux by the adaptive observer. It is a waveform diagram for explaining the operation.

First, FIG. 2 will be described. Here, speed controller 1, magnetic flux setting device 2, vector control unit 3, power converter 4, induction motor 5
And a vector control type induction motor driving device composed of a speed detector 6 and a torque command setting device 7, a gain calculation unit 8 and an adaptive observer 9. However, the induction motor is unloaded. As shown in FIG. 3, the adaptive observer 9 internally includes the primary voltage V ₁ and the current i ₁ of the induction machine. 91A for calculating the secondary magnetic flux in accordance with
_{From 1} (i _1α , i _1β ) and velocity ω _r The calculation unit 91B for calculating the secondary magnetic flux in accordance with the above, the controller 92 for adjusting the circuit constant so that the calculation results of the equations (1) and (2) match, and the error compensating means 93 are provided. The estimation result of the machine equivalent circuit constant, the secondary magnetic flux absolute value φ ₂ and the output torque T represented by the following equation are output from the magnetic flux / torque calculating unit 94.

In the vector control type induction motor drive device, the gain calculation unit 8 uses the torque component current gain (L / M) ^* and the excitation current gain (1 /
When M) ^* and slip adjustment gain R ₂ ^* are set and a constant torque command T ^* is given by the torque command setter 7, the following relationship holds.

I ₁ ² = I _d ^{* 2} + I _q ^{* 2} (I ₁ ; primary current effective value) …… (4) ω _S = ω _S ^* ＝ R ₂ ^* / φ ₂ ^{* 2} …… (5) where I _d ^* is the excitation current command, I _q ^* is the torque current command,
It is expressed by the following equation.

I _d ^* = (1 / M) ^* φ ₂ ^* ... (6) I _q ^* = (L ₂ / M) ^* T ^* / φ ₂ ^* ... (7) Therefore, output torque and secondary magnetic flux In order to make the command values T ^* , φ ₂ ^* and the measured values T, φ ₂ by the adaptive observer match, each gain of the vector control induction motor drive unit is set according to the flow of FIG. To adjust.

Initial gain setting For example, the torque current gain (L ₂ / M), excitation current gain (1 / M), and slip adjustment gain R ₂ (first-order conversion value) obtained from the rating and characteristics of the induction machine are set in advance. Start the controlled induction motor drive. For faster adjustment, it is desirable to set each gain, which is obtained by calculating the induction machine equivalent circuit constant by the adaptive observer, as follows.

However, Indicates the value estimated by the adaptive observer.

Excitation current gain adjustment T ^* = T = 0, I _q ^* = I _q = 0, ω _S ^* = ω _S
If = 0 and ω _r = constant, from equation (6), φ ₂ ^* = (1 / M) ^{* -1} I _d ^* = MI _d ^* φ ₂ must be set, but (1 / M) ^* Φ ₂ if there is an error
= Φ ₂ ^* does not hold. Therefore, in the gain calculator 8, φ ₂ = φ ₂
Change the excitation current adjustment gain as follows so that it becomes ^* .

Measurement of output torque and secondary magnetic flux Make the output of the speed controller 1 forcibly the torque command given from the torque setting device 7, and set the speed lower limit with the torque command pattern as shown in Fig. 4 (b). Output torque when acceleration / deceleration is performed as shown in Fig. 4 (a) between the value (ω _r ) min and the upper limit (ω _r ) max, and acceleration is performed with a constant torque command T _0.
T _a , secondary magnetic flux φ _2a (see Fig. 4 (c)) and output torque when decelerated with a constant torque command −T ₀ −T _b , secondary magnetic flux φ _2b
(See Fig. 4 (c)) is measured with an adaptive observer. Here, the output torque T of the induction machine and the secondary magnetic flux φ ₂ can be expressed by the following equations.

From the above equation, T _a = T _b and φ _2a = φ _2b , but to reduce the measurement error, take the average as in the following equation. The average value is shown with (-).

Output torque relative to the absolute value of tolerance epsilon _T of the difference between a checking torque command T ₀ of the secondary magnetic flux and the output torque average value, | T ₀ - | met <ε _T ...... (12), and the magnetic flux When the absolute value of the difference between the command φ ₂ and the secondary magnetic flux average value ₂ satisfies the following equation | φ ₂ ^* − ₂ | <ε _φ …… (13) for the allowable error ε _φ , the adjustment is terminated If the above formula is not satisfied, make the following adjustments.

Adjustment of current gain for torque component and slip adjustment gain To keep the exciting current _Id constant, near the steady value (ω _S0 ,
Of small changes ΔT, Δφ ₂ , Δω _S , ΔI _q (“Δ” indicates small changes) in I _d0 , I _q0 , T ₀ , φ ₂₀ (subscript “0” indicates a steady value) From the equation (10), the relation is R ₂ ΔT = φ ₂₀ ² Δω _S +2 φ ₂₀ ω _S0 Δφ ₂ …… (14) Therefore, ΔT and Δφ ₂ are set as ΔT = −T ₀ , Δφ ₂ = ₂₋ φ ₂ ^* (16), Substituting into Eqs. (14) and (15) as Δω _S , ΔI
_q is Therefore, if ΔT and Δφ are generated due to the control error, the torque current gain and the slip adjustment gain are By replacing with, the control error can be canceled. Therefore, in this step, the gain calculation unit 7
The gain is corrected according to the equations (0) and (21), and then the procedure returns to.

At the end of the adjustment, Then, the gain of the vector control type induction motor drive device is automatically adjusted.

〔The invention's effect〕

According to the present invention, the secondary magnetic flux and the output torque can be measured by adding the adaptive observer of the induction motor.
The control error of the secondary magnetic flux and output torque can be detected, and the secondary magnetic flux and output torque that are equal to the command value can be obtained regardless of the control error of the vector control unit and power converter and the setting error of the gain. The advantage is that the gain can be automatically adjusted.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flow chart showing an embodiment of the present invention.
Fig. 3 is a block diagram showing the entire system to which the present invention is applied, Fig. 3 is a block diagram showing a concrete example of the adaptive observer of Fig. 2, and Fig. 4 is a measurement of output torque and secondary magnetic flux by the adaptive observer. FIG. 5 is a waveform diagram for explaining the operation, and FIG. 5 is a block diagram for explaining a conventional example of the control gain adjusting method. Explanation of code 1,101 …… Speed adjuster, 2,102 …… Magnetic flux setter, 3,105…
... Vector control unit, 4 ... Power converter, 5 ... Induction motor, 6 ... Speed detector, 7 ... Torque command setter, 8 ...
… Gain calculator, 9 …… Adaptive observer, 10 …… Control device,
91A, 91B ... Secondary magnetic flux calculation unit, 92 ... Adjuster, 93 ... Error compensation means, 94 ... Flux / torque calculation unit, 103 ... Torque current gain, 104 ... Excitation current gain, 106 ... Secondary resistance calculator.

Claims (1)

[Claims] 1. A vector control type motor driving device (driving device) for controlling an induction motor by dividing its current into an exciting current component parallel to a secondary magnetic flux and a torque current component orthogonal thereto.
On the other hand, the first magnetic flux calculation unit that calculates the secondary magnetic flux from the primary current detection value and the primary voltage detection value, and the primary magnetic flux detection value and the rotation speed
The second magnetic flux calculation unit that calculates the next magnetic flux, the controller that adjusts the induction motor equivalent circuit constant to match the calculation results of the first and second magnetic flux calculation units, the output of the first magnetic flux calculation unit, and the primary current detection An adaptive observer consisting of a torque calculator for estimating and calculating the output torque from the value, a torque setter for generating an output torque command when adjusting the control gain, and a secondary magnetic flux equivalent to the induction motor output from the adaptive observer. The circuit constant, the output torque, and the torque command output from the torque setting device are input, and the exciting current gain that is the reciprocal of the mutual inductance and the torque current gain that is the value obtained by dividing the secondary inductance by the mutual inductance, A calculation means for calculating a slip adjustment gain, which is a secondary resistance, is provided, and the gain calculation means is configured to adjust the control gain and to output the induction output from the adaptive observer. The exciting current gain, the torque current gain, and the slip adjustment gain of the drive unit were set using the motor equivalent circuit constant, and the exciting current gain was adjusted using the secondary magnetic flux estimated by the adaptive observer during no-load operation. After that, the current gain and the slip adjustment gain are adjusted so that the output torque estimated by the adaptive observer during acceleration / deceleration operation and the deviations between the secondary magnetic flux and its command value fall within the allowable values. A control gain adjustment method for a vector control type induction motor drive device.