KR100825158B1 - Rotary electric machine constant measuring method - Google Patents

Abstract

It is an object of the present invention to provide a rotary electric constant measuring device and a constant measuring method capable of performing constant water measurement in a non-rotating state without taking a complicated configuration or method for a rotary electric driven by an inverter.

A constant frequency and variable voltage supplied via a power converter for variable speed operation of a rotary electric constant measuring device, comprising: a voltage command calculator for giving a voltage command value to a power converter, a current detector for detecting a current flowing in the rotating electric machine; And a time measuring instrument for measuring the time for which the electric current of the rotary electric current flows, and an integer arithmetic operator for calculating the constant of the electric rotary electric machine from the detected current and time, and giving a voltage command value in a step shape to change the current value at that time. Is measured from an arbitrary time T1 to T2, and the secondary time constant of the rotary electric machine is obtained from the change amount.

Description

How to measure the constant of rotary electricity {ROTARY ELECTRIC MACHINE CONSTANT MEASURING METHOD}

TECHNICAL FIELD The present invention relates to an apparatus and a method for measuring the electrical constant of a rotating electric machine driven by an inverter with no rotation.

As a conventional technique, there is a method of measuring a winding resistance, a no load test, and a restraint test shown in JEC-37 to obtain a rotary electric constant. Moreover, there exists patent document 1 as a method of identifying the constant of an induction motor in the state which stopped the rotary electric machine. In this method, single-phase alternating current was supplied to a rotary electric machine, the d-axis current detection value or the q-axis current detection value was Fourier series expansion, and the constant of a rotary electric machine was calculated | required.

Moreover, patent document 2 is another method. In this method, a constant value is given to the rotating electric machine as a voltage command value, the current value flowing through the rotating electric machine at that time is measured, and the current value is converged to a constant value to use the constant of the rotating electric machine. Was saving.

Patent Document 1: Japanese Patent Laid-Open No. 7-55899

Patent Document 2: Japanese Patent Application Laid-Open No. 2002-199798

In the above prior art, the method shown in JEC-37 requires operations such as fixing and releasing of the rotor of the rotating electric machine during the no-load test and the restraint test, and a surface which is not suitable for automatic measurement by inverter drive is required. have. In addition, in the no-load test, it is necessary to operate by a rotating electric unit, and when the load is already coupled, the operation of disconnecting the load once and rotating it by the rotating electric unit requires a problem of poor efficiency. .

Moreover, in the method shown in Patent Document 1, since single-phase alternating current is applied and obtained using Fourier series expansion, there is a problem that the software becomes complicated, the processing time of the software is long, and the software requires a large storage capacity. .

In addition, in the method shown in Patent Document 2, it is necessary to flow a current many times, and because there are many approximations, the software becomes complicated, the processing time of the software is long, and there is a problem that the software requires a large storage capacity. .

It is an object of the present invention to provide a rotary electric constant measuring device and a constant measuring method capable of performing constant water measurement in a non-rotating state, without taking complicated configurations or methods for rotating electrics driven by an inverter.

In the rotary electric constant measuring apparatus according to the present invention, a variable frequency, variable voltage is supplied via a power converter, the variable speed operation of the rotary electric constant measurement device, the voltage command calculator for giving a voltage command value to the power converter, And a current detector for detecting a current flowing through the rotary electric machine, a time meter for measuring the time for the current of the rotating electric current to flow, and an integer calculator for calculating the constant of the rotary electric machine from the detected current and time. It is given in a step shape, and the change of the current value at that time is measured from an arbitrary time T1 to T2, and the secondary time constant of the rotating electric machine is obtained based on the change amount.

In the constant measuring method of the rotary electric machine according to the present invention, a constant frequency and a variable voltage are supplied through a power converter to measure the secondary time constant of the rotating electric machine in which the variable speed operation is performed. The voltage command value is given in a step shape to measure a current value at a predetermined time flowing in the rotary electric machine and a time corresponding to the half life of the current value, and a straight line based on the current value at the predetermined time and the current value corresponding to the half life. The secondary time constant is calculated by an approximation equation based on the interpolation current point at time zero obtained by interpolation.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram of the rotary electric constant measuring device concerning Embodiment 1 of this invention.

2 is a diagram showing a T-type equivalent circuit of a general induction motor.

3 is a diagram showing a voltage command signal and a current response signal in Embodiment 1 of the present invention.

4 is a diagram illustrating a voltage command signal and a current response signal in Embodiment 2 of the present invention.

5 is a flowchart showing a measuring method according to the first embodiment of the present invention.

6 is a flowchart showing a measuring method according to the second embodiment of the present invention.

<Description of the code>

1 turn electric,

2 power converter,

3 voltage command calculator,

4 current detector,

5 hour instrument,

6 integer operator.

EMBODIMENT OF THE INVENTION Hereinafter, Embodiment 1 of this invention is described.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram for demonstrating the structure of the rotary electric constant measurement apparatus which concerns on embodiment of this invention, FIG. 2 is a figure which shows the T type equivalent circuit of a general induction motor, and FIG. It is a figure which shows a voltage command signal and a current response signal. 5 is a flowchart showing a constant measuring method according to the first embodiment.

1 shows the case where the secondary time constant of a rotating electric machine 1 such as an induction motor driven by an inverter is generated by a power converter 2 that generates an output voltage according to the voltage command value from the voltage command calculator 3. The schematic configuration of the water purification device shows a current detector 4 for detecting a current flowing through the rotary electric machine 1, a time measuring device 5 for measuring time with respect to a state where the current is changing, and a current detector ( A constant calculator 6 for calculating the constant of the rotary electric machine 1 is provided based on the current value detected from 4) and the time measured by the time measuring instrument 5.

And this constant measuring apparatus produces | generates the voltage command value in the voltage command calculator 3 based on the predetermined voltage command value, and outputs the voltage based on the voltage command value from the power converter 2 to the rotating electric machine 1. When supplied, the current flowing in the rotary electric machine 1 is detected by the current detector 4, the constant value calculator 6 stores the current value, and is based on the current value in the time meter 5. The time is measured, and the integer arithmetic operation 6 calculates the secondary time constant based on the stored current value and the time measured value.

Next, the secondary time constant measuring method of the rotary electric machine 1 which concerns on Embodiment 1 is demonstrated.

As an equivalent circuit of the rotary electric machine 1, the T-type equivalent circuit of the general induction motor shown in FIG. 2 is demonstrated as an example. In the drawing, Rs: primary side resistance, Ls: primary side leakage inductance, Lr: secondary side leakage inductance, M: mutual inductance, Rr: secondary side resistance, is: primary side current, vs: primary side voltage. In addition, Ts: 1st time constant, Tr: 2nd time constant, (sigma): leakage coefficient are defined by Formula (1)-(3).

[Equation 1]

(1)

(One)

[Equation 2]

(2)

(2)

[Equation 3]

(3)

(3)

The transfer function G (s) from voltage vs to current is is shown in (4). It is also the s: Laplace operator.

[Equation 4]

(4)

(4)

Here, in the region where the frequency is sufficiently lower than Ts + Tr / σTsTr, it can be approximated as in Equation (5).

[Equation 5]

(5)

(5)

Next, a method of giving a voltage command value to the power converter 2 will be described. In Fig. 3A, the voltage command value 0 [V] is given until time zero. Then, at time 0, the voltage command value VA [V] finally converged on the current IA [A] is given.

In addition, since IA is a current having a value of time O, depending on the state of the rotary electric machine 1, the current IU_INF and the initial value I (0) when IA is sufficiently long as shown in Fig. 3B. Let's assume the difference.

IA = IU_INF-I (0) (6)

It is devised using the equation (5) for the current response when the voltage command value is changed to rise in a step shape from O to VA [V] as shown in Fig. 3 (a). The final value IU_INF of the current is from the final value theorem s → O

[Equation 6]

(7)

(7)

to be. The current I (ΔT) immediately after the voltage cascade is applied from the initial value theorem s → ∞.

[Equation 7]

(8)

(8)

to be. (Step S11 of Fig. 5)

In addition, the current of the step response changes at the time constant (Ts + Tr). This change is shown in Fig. 3 (b).

When the voltage cascades at time 0 seconds, the equation (5) ignores frequencies higher than Ts + Tr / σTsTr, and when Rs ≒ Rr, Ls ≒ Lr,

[Equation 8]

(9)

(9)

An approximation of is established. Here, the time T1 is set to a value sufficiently larger than? Ls / 2Rs. At time T1 [sec], the current is measured and stored as IB [A] as the difference between the current at IU_INF [A] and time T1.

IB = IU_INF-I (T1) (10)

At the same time, the current IC is stored as IB / 2 [A]. (Step S12 of Fig. 5)

Continue to measure current and condition

IU_INF-I (t) = IC (11)

It is stored as T2 [seconds].

 The relationship between the half-life of the current amplitude and the time constant is shown in (12).

[Equation 9]

(12)

(12)

 (13) is obtained from (12). The time constant (Ts + Tr) is obtained by the equation (13). (Step S13 of Fig. 5)

[Equation 10]

(13)

(13)

By interpolating linearly based on point B and point C in FIG.3 (b), the point Z which is an interpolation current point in time 0 is obtained. (Step S14 of FIG. 5)

 From the relationship between this interpolation current point Z point and (8)

 [Equation 11]

Since the relation of (14) is derived.

[Equation 12]

(14)

(14)

From (13) and (14)

 [Equation 13]

(15)

(15)

The second time constant Tr is obtained. (Step S15 of Fig. 5)

As described above, according to the first embodiment, the voltage command value rising in the step shape as the voltage command value of the power converter 2 is given, and the current value of the predetermined time flowing through the rotary electric machine 1 and the current value The second time constant is calculated by an approximation equation based on the interpolated current point at time zero obtained by measuring the time corresponding to the half life and linearly interpolating based on the current value at the predetermined time and the current value corresponding to the half life. By doing so, the secondary time constant can be easily calculated in the non-rotating state, and the processing time which can be executed by simple software can be shortened as compared with the prior art.

Embodiment 2.

Next, Embodiment 2 will be described. The configuration of the constant electric measurement device of rotary electric machine is the same as that of the first embodiment. 4 is a diagram illustrating a signal of a voltage command signal and a current response in the second embodiment. FIG. 6 is a flowchart showing a constant measuring method according to the second embodiment. FIG. Also in this case, the T-type equivalent circuit similar to the first embodiment is considered as the equivalent circuit of the rotary electric machine 1.

Next, a method of giving a voltage command value to the power converter 2 will be described. In Fig. 4A, the voltage command value VD [V] is given until time zero. After a sufficiently long time for the current value to converge to the constant value ID [A] has elapsed with respect to the voltage command value VD, the voltage command value is lowered stepwise from VD to O [V] as shown in Fig. 4 (a). Think about the current response when you change it.

First of all, the final value of the current IU_INF is 0 [A].

Next, since the current I (ΔT) immediately after the voltage step drop is considered to be the step response of the voltage VD? 0 [V],

 [Equation 14]

(16)

(16)

It becomes (Step S21 of FIG. 6)

In addition, the current of the step response changes at the time constant (Ts + Tr). This change is shown in Fig. 4B.

When voltage changes stepwise at time 0 seconds, (5) ignores frequencies higher than Ts + Tr / σTsTr, and sets T3 to a value sufficiently larger than σLs / 2Rs from (9). At time T3 [sec], the current is measured and stored as IE [A]. At the same time, the current IF is stored as IE / 2 [A]. (Step S22 of Fig. 6)

Continue to measure current

I (t) = IF (17)

The stored time is stored as T4 [second]. (Step S23 in FIG. 6)

By interpolating linearly between point E and point F in FIG. 4 (b), the interpolated current point Y point which is the interpolated current point at time 0 is obtained. (Step S24 of FIG. 6)

From the relationship between this interpolation current point Y point and (16)

 [Equation 15]

Since the relation of (18) is derived.

[Equation 16]

(18)

(18)

From (13) and (18)

Formula 17

(19)

(19)

The second time constant Tr is obtained. (Step S25 of Fig. 6)

As described above, according to the second embodiment, as the voltage command value of the power converter 2, the voltage command value falling in the step shape is given, and the current value at the predetermined time flowing through the rotary electric machine 1 and the current value By measuring the time corresponding to the half life and calculating the second time constant by an approximation equation based on the interpolated current point at time zero obtained by linear interpolation based on the current value at the predetermined time and the current value corresponding to the half life. In this case, the secondary time constant can be easily calculated in a non-rotating state, and can be executed by simple software as compared with the prior art, thereby reducing the processing time.

According to the present invention, the measurement of the constant of the inverter driven rotary electricity can be performed by a simple configuration and method without rotating the rotary electricity, and the processing time can be shortened by simple software compared with the conventional software. There is an effect that does not require a large memory capacity for.

Claims (6)

delete delete delete delete In the constant electric measurement method of the rotary electric machine which measures the secondary time constant of the rotary electric machine by which a variable frequency and a variable voltage are supplied through a power converter, and a variable speed operation is performed, Providing a voltage command value rising in a step shape as a voltage command value of the power converter, measuring a current value of a predetermined time flowing through the rotary electric machine and a time corresponding to a half-life of the current value, and A secondary time constant is calculated by the following approximation equation based on the interpolation current point at time zero obtained by linear interpolation based on the current value at time and the current value corresponding to the half life. Method for measuring the constant of rotating electricity. [Equation 18]

Tr: 2nd time constant IA: Current value finally converged by voltage command value VA T1: Time set to a value sufficiently larger than σ Ls / 2Rs (Ls: primary leakage inductance, Lr: secondary leakage inductance, σ: leakage coefficient) IB: current value at time T1 IC, T2: Current value stored as IB / 2 and time of that current value In the constant electric power measuring method of the rotary electric machine which measures the secondary time constant of the rotary electric machine by which a variable frequency and a variable voltage are supplied through a power converter, and a variable speed operation is performed, A voltage command value rising in a step shape as a voltage command value of the power converter is provided, the time corresponding to the current value at a predetermined time flowing through the rotary electric machine and the half-life of the current value is measured, and the current value at the predetermined time. And a second time constant is calculated by the following approximation formula based on the interpolation current point at time zero obtained by linear interpolation based on the current value corresponding to the half-life. [Equation 19]

Tr: 2nd time constant ID: Current value flowing when voltage command value VD T3: Time set to a value sufficiently larger than σ Ls / 2Rs (Ls: primary leakage inductance, Lr: secondary leakage inductance, σ: leakage coefficient) IE: current value at time T3 IF, T4: Current value stored as IE / 2 and time of the current value

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