JP5023439B2 - Induction motor control method - Google Patents

Description

  The present invention relates to a method for controlling an induction motor driven by a power conversion device such as an inverter, and more particularly to a method for deriving an excitation inductance as a motor constant used when the induction motor is controlled at a variable speed.

  FIG. 11 is a circuit configuration diagram showing a conventional example of this type of induction motor control device, including an induction motor control method disclosed in Patent Document 1 below.

In FIG. 11, reference numeral 1 denotes each of the three-phase voltage command values v _U ^* , v _V ^* , and v _W ^* (alternating current amounts) from the control device 10 described later to form an inverter main circuit that incorporates PWM calculation. An inverter that converts the on / off drive signal to the semiconductor switch and generates a three-phase AC voltage from the inverter main circuit based on the on / off drive signal, and 2 is an induction motor fed by the inverter 1, 3 is a current detector for detecting a current from the inverter 1 to the induction motor 2, that is, a primary current i ₁ of the induction motor 2. 10 is a command value calculator 11, an integrator 12, coordinate converters 13 and 14, and a constant calculation. And a control device that controls the induction motor 2 through the inverter 1 at a variable speed.

In this control device 10, the command value calculator 11 instructs the primary angular frequency command value ω ₁ ^{* of the} induction motor 2 to be commanded, and the phase obtained by time integration calculation by the integrator 12 using the primary angular frequency command value ω ₁ ^*. I _1d , i _{1q obtained} by converting the primary current i ₁ of the induction motor 2 detected by the current detector 3 based on the angle command value θ ₁ ^* into three-phase to two-phase conversion and dq axis conversion by the coordinate converter 13; The d-axis voltage command value v _1d ^* and q-axis voltage command value v _1q ^* of the induction motor 2 are calculated from the excitation inductance calculation value Lm ^{# of the} induction motor 2 obtained from the constant calculator 15 described later and other motor constants. These values are output to the coordinate converter 14. In the coordinate converter 14, the voltage command obtained by subjecting the d-axis voltage command value v _1d ^* and the q-axis voltage command value v _1q ^* to α-β conversion and two-phase to three-phase conversion based on the phase angle command value θ ₁ ^*. Values v _U ^* , v _V ^* , and v _W ^* are generated, and the induction motor 2 is variable-speed controlled based on these voltage command values.

This control method of the induction motor 2 by the control device 10, the inverter 1, and the current detector 3 is called as adding a magnetic flux adjusting function to a general V / f control method.
JP 2003-244982 A (pages 3 and 4, FIG. 1 and the like)

In the conventional control device 10 for the induction motor 2 shown in FIG. 11, the constant calculator 15 first rotates the induction motor 2 in a no-load state, and at this time, the primary angular frequency command value ω ₁ ^* and the d-axis voltage The excitation inductance calculation value Lm ^# as the motor constant of the induction motor 2 is derived based on the command value v _1d ^* , the q-axis voltage command value v _1q ^*, and the current detection value i _1d. In the machine 15, when the induction motor 2 is incorporated in a mechanical facility or the like and it is not permitted to rotate the induction motor 2 in a no-load state, it is difficult to use the above derivation method.

  An object of the present invention is to provide a method of controlling an induction motor that can derive an excitation inductance as a motor constant when performing variable speed control of the induction motor without rotating the induction motor.

The control method of the induction motor according to the first aspect of the present invention is the voltage command value corresponding to the rated induction voltage of the induction motor commanded from the power converter that drives the induction motor before the normal operation of the induction motor. A DC voltage is generated based on the induction motor and applied to the induction motor. At this time, the excitation current of the induction motor is obtained by calculation based on the detected value of the current flowing in the induction motor and the rated induced voltage. The excitation inductance of the induction motor is obtained by calculation based on the calculated value, and the calculated value of the excitation inductance is used as a motor constant in variable speed control of the induction motor .

A second invention is the method of controlling an induction motor according to the first invention ,
A time T ₀ based on a value obtained by dividing the rated secondary magnetic flux value of the induction motor by the rated induced voltage value is calculated in advance, and the time T ₀ after applying the DC voltage to the induction motor is The excitation current calculation value of the induction motor is derived from the current detection value of the motor when the elapsed time, the rated induced voltage value, and the secondary resistance value of the induction motor, and the excitation inductance calculation value is It is based on a value obtained by dividing the next magnetic flux value by the exciting current calculation value.

A third invention is the method of controlling an induction motor according to the first invention,
The induction motor of previously calculated time T _0, based on the value obtained by dividing the rated secondary magnetic flux value at the rated induced voltage value, N corresponding to the time T ₀ (N ≧ 1) number of time T ₁ , T ₂ ,... _TN (T ₁ <T ₂ <... <T _N <T ₀ ) and the time T ₁ , T ₂ after applying the DC voltage to the induction motor ,..., T _N , T ₀ each time when the current detection value of the motor, the rated induced voltage value, and the secondary resistance value of the induction motor are used to calculate the excitation current calculation value of the induction motor. The excitation inductance calculation value is obtained by multiplying the rated secondary magnetic flux value by a coefficient T ₁ / T ₀ , T ₂ / T ₀ ,... _TN / T ₀ , T ₀ / T _0, respectively. It is based on each value obtained by dividing the corresponding exciting current calculation value.

4th invention is the control method of the induction motor of the said 2nd or 3rd invention ,
Before applying the DC voltage (V _F ) to the induction motor, first, a DC voltage (V _R ) having a polarity opposite to that of the V _F and having substantially the same amplitude is applied for T _R (T _R <T ₀ ). characterized by the time the said time T _R by applying the DC voltage (V _F) immediately after has passed the start point of the T _0.

A fifth invention is the method of controlling an induction motor according to the second or third invention ,
After the DC voltage (V _F ) is applied to the induction motor for the time T ₀ , a DC voltage (V _R ) having a polarity opposite to that of the V _F and substantially the same amplitude is applied for the time T ₀ , and the DC voltage ( An average value of the excitation inductance calculation value in V _F ) and the excitation inductance calculation value in the DC voltage (V _R ) is obtained, and this average value is used as a new excitation inductance calculation value of the induction motor. To do.

A sixth invention is the method of controlling an induction motor according to the first invention ,
Calculated induced voltage computation value of the induction motor on the basis of the secondary resistance value of the detection value and the induction motor of the current flowing immediately after the previous SL DC voltage is applied to said induction motor to said induction motor,
A period during which the DC voltage is applied to the induction motor by obtaining a secondary magnetic flux calculation value of the induction motor from the induced voltage calculation value, the rated induced voltage value, and a rated secondary magnetic flux value of the induction motor. An excitation current calculation value of the induction motor is obtained based on a detected value of the current flowing through the induction motor and the rated induction voltage value , and the induction motor is calculated from the secondary magnetic flux calculation value and the excitation current calculation value. The excitation inductance calculation value is obtained, and this excitation inductance calculation value is used as the motor constant in the variable speed control of the induction motor.

A seventh invention is the method for controlling an induction motor according to the first invention ,
Detection value and the respective current flowing through the induction motor at the start and end points of a predetermined interval during the period of pre-Symbol DC voltage is applied to the induction motor, the secondary resistance value of the induction motor Based on the induced voltage calculated value, the rated induced voltage value, and the rated secondary magnetic flux value of the induction motor, the secondary magnetic flux calculated value of the induction motor is determined based on the induced voltage calculated value of the induction motor. A calculation value of the excitation current of the induction motor is obtained based on a detected value of the current flowing in the induction motor and the rated induced voltage value during a period in which the DC voltage is applied to the induction motor, and the secondary magnetic flux An excitation inductance calculation value of the induction motor is obtained from the calculation value and the excitation current calculation value, and the excitation inductance calculation value is set as a motor constant in variable speed control of the induction motor.

An eighth invention is the method for controlling an induction motor according to the sixth or seventh invention , wherein
A time T ₀ based on a value obtained by dividing the rated secondary magnetic flux value of the induction motor by the rated induced voltage value is calculated in advance, and the time T ₀ after applying the DC voltage to the induction motor is A calculated excitation current value of the induction motor is derived from a current detection value of the motor when the elapsed time, the rated induced voltage value, and a secondary resistance value of the induction motor.

A ninth invention is the control method for an induction motor according to the eighth invention ,
Before applying the DC voltage (V _F ) to the induction motor, first, a DC voltage (V _R ) having a polarity opposite to that of the V _F and having substantially the same amplitude is applied for T _R (T _R <T ₀ ). characterized by the time the said time T _R by applying the DC voltage (V _F) immediately after has passed the start point of the T _0.

  According to the present invention, since the excitation inductance can be derived without rotating the induction motor, even when the induction motor is used for an application that is not allowed to rotate in a no-load state, the induction motor has high accuracy. Speed control and torque control.

  FIG. 1 is a circuit configuration diagram of an induction motor control apparatus showing a first embodiment of the present invention. In this figure, components having the same functions as those of the conventional configuration shown in FIG. The description thereof is omitted here.

  That is, in the control device 20 of the induction motor 2 shown in FIG. 1, instead of the command value calculator 11 and the constant calculator 15, any one of the command value calculators 21 to 23 and the constant calculator 24 are used. Any one of -27.

  FIG. 2 is a partial detailed circuit configuration diagram of the command value calculators 21 to 23 shown in FIG. 1. The command value calculator 21 includes an induced voltage generator 21a and a voltage command value calculator 21b as part thereof. Similarly, the command value calculator 22 includes an induced voltage generator 22a and a voltage command value calculator 22b, and the command value calculator 23 includes an induced voltage generator 23a and a voltage command value calculator 23b.

  FIG. 3 is a detailed circuit diagram of the constant calculators 24 to 27 shown in FIG. 1. The constant calculator 24 is formed of an exciting current calculator 24a and an exciting inductance calculator 24b. 25, from the exciting current calculator 25a and the exciting inductance calculator 25b, the constant calculator 26 from the exciting current calculator 26a and the exciting inductance calculator 26b, and the constant calculator 27 from the exciting current calculator 27a and the excitation inductance calculator 27b. Is formed.

  FIG. 4 is a circuit configuration diagram of an induction motor control apparatus showing a second embodiment of the present invention. Components having the same functions as those of the circuit configuration shown in FIG. 1 is basically the same except that the d-axis component of the induction motor 2 is used for the voltage command value and the current detection value, whereas the q-axis component is used in FIG.

  That is, the control device 30 of the induction motor 2 shown in FIG. 4 includes any one of the command value calculators 31 to 33 instead of the command value calculators 21 to 23.

  FIG. 5 is a partial detailed circuit configuration diagram of the command value calculators 31 to 33 shown in FIG. 4. The command value calculator 31 includes an induced voltage generator 31a and a voltage command value calculator 31b as a part thereof. Similarly, the command value calculator 32 includes an induced voltage generator 32a and a voltage command value calculator 32b, and the command value calculator 33 includes an induced voltage generator 33a and a voltage command value calculator 33b.

The derivation method of the calculated excitation inductance Lm ^# of the induction motor 2 in the control device 20 of the induction motor 2 shown in FIG. 1 and the control device 30 shown in FIG. 4 is shown in the equivalent circuit diagram of the induction motor 2 shown in FIG. This will be described below with reference to the operation waveform diagrams shown in FIGS.

FIG. 6 shows an equivalent circuit diagram of the induction motor 2 in a stationary state (slip s = 1). In this figure, the excitation current i _M is expressed by the following equation (1). In the following formula, the motor constants R ₁ , R ₂ , Lσ, etc. other than the excitation inductance Lm are fixed values or values obtained by a known calculation method.
[Equation 1]
i _M = i ₁ −i ₂ = i ₁ −e _2DC / R ₂
Here, the induced voltage e _2DC is expressed by the following formula 2.
[Equation 2]
e _2DC = v ₁ − (R ₁ + pLσ) i ₁
Here, p is a differential operator.

The exciting inductance Lm is expressed by the following equation (3).
[Equation 3]
Lm = φ ₂ / i _M
Here, φ ₂ is the secondary magnetic flux of the induction motor 2.

Further, when a DC voltage corresponding to the induced voltage e _2DC is applied to the induction motor ₂ , there is a relationship of the following formula 4 between the DC voltage passing time T and the φ ₂ , e _2DC .
[Equation 4]
φ ₂ = e _2DC · T
FIG. 7 is an operation waveform diagram showing the first embodiment of the control method of the induction motor according to the present invention. The command value calculator 21, the constant calculator 24, or the constant calculator 24 in the controller 20 shown in FIG. 6 is an operation waveform diagram in the command value calculator 31 and the constant calculator 24 in the control device 30 shown in FIG.

That is, when a DC voltage is applied from the inverter 1 to the induction motor 2 before normal operation and the motor is allowed to flow without rotating to calculate the excitation inductance Lm, the command value calculator 21 in the control device 20 is used. Then, when a DC induced voltage e _2DC0 corresponding to the rated secondary magnetic flux value of the induction motor 2 is generated as the induced voltage command value e _2DC ^* from the induced voltage command value generation unit 21a as shown in FIG. In the unit 21b, the d-axis voltage command value v as a value corresponding to the primary voltage v ₁ of the induction motor 2 is calculated from the induced voltage e _2DC0 and the current detection value i _1d from the coordinate converter 13 using the equation (2). _1d ^* is output. At this time, since the induced voltage command value e _2DC ^* is a DC voltage, the q-axis voltage command value v _1q ^* from the voltage command value calculator 21b and the current detection value i _1q from the coordinate converter 13 are Zero.

The constant calculator 24 calculates the time T ₀ based on the equation 4 from the rated secondary magnetic flux value φ _{20 of the} induction motor 2 and the corresponding DC induced voltage e _2DC0 in advance, and the excitation current calculator 24a. Then, the excitation current of the induction motor 2 is calculated from the voltage command value (v _1d ^* ), the current detection value (i _1d ), and the secondary resistance value (R ₂ ) when the time T ₀ has passed, based on the equation ( ₁ ). The calculated value i _M ^# is obtained, and the exciting inductance calculating unit 24b derives the calculated exciting inductance value Lm ^# from the excited current calculated value i _M ^# and the induced voltage e _2DC0 based on the equation (3). Is stored in a memory (not shown) in the constant calculator 24, and the stored value is output to the command value calculator 21. A memory for storing the magnetizing inductance calculation value Lm ^# obtained by the constant calculator 24 may be provided in the command value calculator 21.

  During the subsequent normal operation, the command value calculator 21 calculates the voltage command value based on the stored value as the motor constant of the induction motor 2 and other motor constants, similarly to the control device 10 shown in FIG. Thus, the induction motor 2 is controlled at a variable speed.

Further, in the command value calculator 31 in the control device 30, when the induced voltage generator 31 a generates a DC induced voltage e _2DC0 corresponding to the rated secondary magnetic flux value of the induction motor 2 as shown in FIG. In the value calculation unit 31b, a q-axis voltage command as a value corresponding to the primary voltage v ₁ of the induction motor 2 is calculated from the induced voltage e _2DC0 and the current detection value i _1q from the coordinate converter 13 using the equation (2). The value v _1q ^* is output. At this time, the d-axis voltage command value v _1d ^* from the voltage command value calculation unit 31b and the current detection value i _1d from the coordinate converter 13 are zero.

In this case, the constant calculator 24 replaces the voltage command value (v _1d ^* ) and current detection value (i _1d ) in the constant calculator 24 of the control device 20 described above with a voltage command value (v _1q ^* ) and current detection. This is basically the same as described above except that the calculated excitation current value i _M ^# of the induction motor 2 is derived based on the value (i _1q ).

  FIG. 8 is an operation waveform diagram showing a second embodiment of the method for controlling the induction motor according to the present invention. The command value calculator 21, the constant calculator 25, or the constant calculator 25 in the controller 20 shown in FIG. 6 is an operation waveform diagram in the command value calculator 31 and the constant calculator 25 in the control device 30 shown in FIG.

That is, in the constant calculator 25, the time T ₀ based on the equation 4 in advance from the rated secondary magnetic flux value φ _{20 of the} induction motor 2 and the corresponding DC induced voltage e _2DC0, and the implementation shown in FIG. In the example, a value T ₁ of T ₀ , for example, about 1/2 (not limited to 1/2) is calculated as N = 1, and the excitation current calculator 25 a first calculates the time T _1. Based on the above equation 1 from the voltage command value (v _1d ^* ), current detection value (i _1d ), induced voltage [e _2DC0 · T ₁ / T ₀ ], and secondary resistance value (R ₂ ) The excitation current calculation value i _M ^# (1) of the induction motor 2 is obtained, and the excitation inductance calculation unit 24b calculates the excitation current calculation value i _M ^# (1) and the induced voltage [e _2DC0 · T ₁ / T ₀ ] from the above. based on equation 3, the exciting inductance calculation value Lm ^# derives (1), then when the time T ₀ has elapsed Voltage command value (v _1d ^*) and the current detection value (i _1d) and the induced voltage (e _2DC00) and the secondary resistance value (R ₂₎ because of the induction motor 2 based on the equation (1) excitation current calculation value i _M ^# (0) is obtained, and the excitation inductance calculation unit 24b _derives the excitation inductance calculation value Lm ^# (0) from the excitation current calculation value i _M ^# (0) and the induced voltage e _2DC0 based on the above equation (3). These derived values are stored in a memory (not shown) in the constant calculator 25, and these stored values are output to the command value calculator 21. A memory for storing the excitation inductance calculation value Lm ^# obtained by the constant calculator 25 may be provided in the command value calculator 21.

  During the subsequent normal operation, the command value calculator 21 calculates the voltage command value based on the stored value as the motor constant of the induction motor 2 and other motor constants, similarly to the control device 10 shown in FIG. Thus, the induction motor 2 is controlled at a variable speed.

As a result, the control method for the induction motor 2 shown in FIG. 8 can derive a calculated value in consideration of the current dependency of the excitation inductance Lm. In the above embodiment, N = 1 is taken as an example. However, when N = 2 or more, T ₁ , T ₂ ,... T _N (T ₁ <T ₂ <... <T _N <T ₀ ) is set and excitation is performed from the voltage command value (v _1d ^* ), current detection value (i _1d ), and secondary resistance value R ₂ for each time T ₁ , T ₂ ,. Current calculation values i _M ^# (1), i _M ^# (2),... _Are obtained, and these calculation values and induced voltages e _2DC0 · T ₁ / T ₀ , e _2DC0 T ₂ / T _{0 ,.} Thus, the calculated inductance values Lm ^# (1), Lm ^# (2),. Thus, by setting one or more N, the induction motor 2 is suitable for highly accurate speed control and torque control of the induction motor from the constant field region to the weak field region. It is.

  FIG. 9 is an operation waveform diagram showing a third embodiment of the control method for the induction motor according to the present invention. FIG. 9 shows the command value calculator 22, the constant calculator 26, or FIG. 6 is an operation waveform diagram in the command value calculator 32 and the constant calculator 26 in the control device 30 shown in FIG.

That is, the control method of the induction motor 2 shown in FIG. 9 is different from the control method shown in FIG. 8 in that the induction motor 2 has a direct current voltage (V _F ) corresponding to the induction voltage e _2DC0 as shown in FIG. First, a DC voltage (V _R ) having a polarity opposite to that of the V _F and having substantially the same amplitude is applied for a period of T _R (T _R <T ₀ ), and immediately after that, the DC voltage (V _F ) is applied. Is the starting point of the times T ₁ and T ₀ when the time T _R elapses. By using this control method, the induction motor when deriving the excitation inductance Lm of the induction motor 2 is obtained. The effect of the residual magnetic flux 2 can be reduced.

It should be noted that the excitation inductance calculation value Lm ^# may be obtained by the method shown in FIG. 7 using the induced voltage command value e _2DC ^* shown in FIG.

  FIG. 10 is an operation waveform diagram showing a fourth embodiment of the method for controlling the induction motor according to the present invention. The command value calculator 23, the constant calculator 27, or FIG. 4 in the controller 20 shown in FIG. 6 is an operation waveform diagram in the command value calculator 33 and the constant calculator 27 in the control device 30 shown in FIG.

That is, the control method of the induction motor 2 shown in FIG. 10 is different from the control method shown in FIG. 8 in that the induction motor 2 is _supplied with the DC voltage (V _F ) corresponding to the induction voltage e _2DC0 as shown in FIG. After applying the time T _0, a DC voltage (V _R ) having a polarity opposite to that of V _F and having substantially the same amplitude is applied for the time T _0. At this time, the DC voltage (V _F ) is shown in FIG. the average value of the exciting inductance calculation value Lm ^# (1 _R) in the excitation inductance calculation value Lm ^# (1 _F) and the time T ₁ shown in FIG. 10 in the DC voltage (V _R) at time T ₁ The average value is the excitation inductance calculation value Lm ^# (1) of the induction motor 2, and the excitation inductance calculation value Lm ^# (0) at the time T ₀ shown in FIG. 10 in the DC voltage (V _F ). And use this control method The Rukoto, hysteresis characteristic of the excitation inductance Lm of the induction motor 2 can be canceled out.

Also, in the embodiments shown in FIGS. 9 and 10, assuming that N = 2 or more, T ₁ , T ₂ ,... T _N (T ₁ <T ₂ <... <T _N <T ₀ ) Set and calculate each excitation current calculation value from the voltage command value, current detection value, and secondary resistance value R ₂ for each time T ₁ , T ₂ ,. Based on this, the respective calculated inductance values may be obtained.

  FIG. 12 is a circuit configuration diagram of an induction motor control apparatus showing a third embodiment of the present invention. In this figure, components having the same functions as those of the conventional configuration shown in FIG. A description thereof will be omitted here.

  That is, in the control device 40 of the induction motor 2 shown in FIG. 12, instead of the command value calculator 11 and the constant calculator 15, any one of the command value calculators 41 and 42 and the constant calculator 43 Any one of -46.

  FIG. 13 is a partial detailed circuit configuration diagram of the command value calculators 41 and 42 shown in FIG. 12, and the command value calculator 41 includes an induced voltage generator 41a and a voltage command value calculator 41b as a part thereof. Similarly, the command value calculator 42 includes an induced voltage generator 42a and a voltage command value calculator 42b.

  FIG. 14 is a detailed circuit configuration diagram of the constant calculators 43 to 46 shown in FIG. 12. The constant calculator 43 is formed of an exciting current calculator 43a, a correction unit 43b, and an exciting inductance calculator 43c. The constant calculator 25 is from the excitation current calculator 44a, the correction unit 44b, and the excitation inductance calculator 44c. The constant calculator 45 is from the excitation current calculator 45a, the correction unit 45b and the excitation inductance calculator 45c, and the constant calculator 46 is The exciting current calculating unit 46a, the correcting unit 46b, and the exciting inductance calculating unit 46c are formed.

  FIG. 15 is a circuit configuration diagram of an induction motor control device showing a fourth embodiment of the present invention, and components having the same functions as the circuit configuration shown in FIG. In FIG. 12, the d-axis component of the induction motor 2 is used for the voltage command value and the current detection value, whereas in FIG. 15, the same except that the q-axis component is used.

  That is, the control device 50 of the induction motor 2 shown in FIG. 15 includes any one of the command value calculators 51 and 52 instead of the command value calculators 41 and 42.

  FIG. 16 is a partial detailed circuit configuration diagram of the command value calculators 51 and 52 shown in FIG. 15. The command value calculator 51 includes an induced voltage generator 51a and a voltage command value calculator 51b as a part thereof. Similarly, the command value calculator 32 includes an induced voltage generator 52a and a voltage command value calculator 52b.

Refer to the operation waveform diagrams shown in FIGS. 17 to 20 for the derivation method of the excitation inductance calculation value Lm ^# of the induction motor 2 in the control device 40 of the induction motor 2 shown in FIG. 12 and the control device 50 shown in FIG. However, the following will be described.

  FIG. 17 is an operation waveform diagram showing a fifth embodiment of the method for controlling the induction motor according to the present invention. The command value calculator 41, the constant calculator 43, or FIG. 15 in the controller 40 shown in FIG. 6 is an operation waveform diagram in the command value calculator 51 and the constant calculator 43 in the control device 50 shown in FIG.

That is, before normal operation, a DC voltage is applied from the inverter 1 to the induction motor 2 to allow the motor to flow without rotating and to calculate the excitation inductance Lm. Then, when a DC induced voltage e _2DC0 corresponding to the rated secondary magnetic flux value of the induction motor 2 is generated as the induced voltage command value e _2DC ^* from the induced voltage generating unit 41a, the voltage command value calculating unit 41b The d-axis voltage command value v _1d ^* as a value corresponding to the primary voltage v ₁ of the induction motor 2 is output from the equation 2 using the current detection value i _1d from the e _2DC0 and the coordinate converter 13. Yes. At this time, since the induced voltage command value e _2DC ^* is a DC voltage, the q-axis voltage command value v _1q ^* from the voltage command value calculation unit 41b and the current detection value i _1q from the coordinate converter 13 are Zero.

In the constant calculator 43, the time T ₀ based on the equation 4 is calculated in advance from the rated secondary magnetic flux value φ _{20 of the} induction motor 2 and the corresponding DC induced voltage e _2DC0, and the excitation current calculator 43a. The excitation current of the induction motor 2 based on the above equation 1 from the voltage command value (v _1d ^* ), the current detection value (i _1d ), and the secondary resistance value (R ₂ ) when the time T ₀ has passed. The calculated value i _M ^# is obtained.

At this time, the correction unit 43b pays attention to the fact that the current (i _M ) to the excitation inductance (Lm) immediately after the voltage command value (v _1d ^* ) is applied to the induction motor 2 can be regarded as almost zero (FIG. 6), the induced voltage calculation from the current detection value (i _1d ) immediately after the voltage command value (v _1d ^* ) is applied and the secondary resistance value (R ₂ ) of the induction motor 2 by the following equation (5) The value e _2DC is determined.
[Equation 5]
e _2DC = R ₂ · i ₁
Further, in the correction unit 43b, the secondary magnetic flux value corrected from the e _2DC obtained from the above equation (5), the rated secondary magnetic flux value (φ ₂₀ ) of the induction motor 2 and the corresponding induced voltage (e _2DC ^* ) ( φ _2C ) is obtained according to the following equation 6 and is output to the excitation inductance calculation unit 24b.
[Equation 6]
φ _2C = (e _2DC / e _2DC ^* ) φ ₂₀
That is, the excitation inductance calculation unit 43c derives the excitation inductance calculation value Lm ^# from the excitation current calculation value (i _M ^# ) and the secondary magnetic flux (φ _2C ) based on the following equation (7). .
[Equation 7]
Lm ^# = φ _2C / i _M ^#
The value derived from Equation 7 is stored in a memory (not shown) in the constant calculator 24 and the stored value is output to the command value calculator 21. A memory for storing the magnetizing inductance calculation value Lm ^# obtained by the constant calculator 43 may be provided in the command value calculator 41.

  During the subsequent normal operation, the command value calculator 41 calculates the voltage command value based on the stored value as the motor constant of the induction motor 2 and other motor constants in the same manner as the control device 10 shown in FIG. Thus, the induction motor 2 is controlled at a variable speed.

In addition, in the command value calculator 51 in the control device 50, when the DC induced voltage e _2DC0 corresponding to the rated secondary magnetic flux value of the induction motor 2 is generated from the induced voltage generator 51a, the voltage command value calculator 51b generates the induced voltage. The q-axis voltage command value v _1q ^* as a value corresponding to the primary voltage v ₁ of the induction motor 2 is output from the equation 2 using the current detection value i _1q from the e _2DC0 and the coordinate converter 13. Yes. At this time, the d-axis voltage command value v _1d ^* from the voltage command value calculation unit 51b and the current detection value i _1d from the coordinate converter 13 are zero.

In this case, the constant calculator 43 replaces the voltage command value (v _1d ^* ) and current detection value (i _1d ) in the constant calculator 43 of the control device 40 with the voltage command value (v _1q ^* ) and current detection. This is basically the same as described above, except that the excitation current calculation value i _M ^# of the induction motor 2 is derived based on the value (i _1q ).

  FIG. 18 is an operation waveform diagram showing the sixth embodiment of the method for controlling the induction motor according to the present invention. The command value calculator 41, the constant calculator 44, or FIG. 15 in the controller 40 shown in FIG. 6 is an operation waveform diagram in the command value calculator 51 and the constant calculator 44 in the control device 50 shown in FIG.

That is, the constant calculator 44 calculates the time T ₀ based on the equation (4) in advance from the rated secondary magnetic flux value φ _{20 of the} induction motor 2 and the corresponding DC induced voltage e _2DC0, and the excitation current calculator Excitation of the induction motor 2 based on the equation 1 from the voltage command value (v _1d ^* ), the current detection value (i _1d ), and the secondary resistance value (R ₂ ) when the time T ₀ has elapsed at 44a. The current calculation value i _M ^# is obtained.

At this time, in the correction unit 44b, the current detection value (i _1d ) immediately after the voltage command value (v _1d ^* ) is applied to the induction motor 2 is primarily delayed by the influence of the leakage inductance Lσ (see FIG. 6). Since the change occurs, the current detection value (i _1d ) changes linearly during the period in which the DC voltage is applied (see FIG. 18). Times t (1) and t (2) from the start of application ), Current i _1Lin equivalent to the formula 5 is obtained from the currents i ₁ (1) and i ₁ (2) flowing through the induction motor 2 in accordance with the following formula 8.
[Equation 8]
i _1Lin = ii (1)
_{-T (1) {i 1 (} 2) -i 1 (1)} / {t (2) -t (1)}
Further, a current i _1Lin at correcting portion above equation (8) in 44b, the following Equation 9 formula from the secondary resistance R ₂ Metropolitan of the induction motor 2, seeking induced voltage calculation value e _2DC.
[Equation 9]
e _2DC = R ₂ · i _1Lin
Further, the correction unit 44b corrects the secondary magnetic flux value corrected from e _2DC obtained from the above equation (9), the rated secondary magnetic flux value (φ ₂₀ ) of the induction motor 2 and the corresponding induced voltage (e _2DC ^* ) ( φ _2C ) is obtained according to the equation (6), and is output to the excitation inductance calculator 24c.

That is, in the excitation inductance calculation unit 44c, a value obtained by deriving the excitation inductance calculation value Lm ^# based on the equation 7 from the excitation current calculation value (i _M ^# ) and the secondary magnetic flux (φ _2C ), The value is stored in a memory (not shown) in the constant calculator 24 and the stored value is output to the command value calculator 21. A memory for storing the magnetizing inductance calculation value Lm ^# obtained by the constant calculator 43 may be provided in the command value calculator 41.

The constant calculator 44 in the control device 50 replaces the voltage command value (v _1d ^* ) and the current detection value (i _1d ) in the constant calculator 44 of the control device 40 with the voltage command value (v _1q ^*). ) And the detected current value (i _1q ), basically the same as described above, except that the excitation current calculation value i _M ^# of the induction motor 2 is derived.

  FIG. 19 is an operation waveform diagram showing a seventh embodiment of the method for controlling the induction motor according to the present invention. The command value calculator 42, the constant calculator 45, or FIG. 15 in the controller 40 shown in FIG. 6 is an operation waveform diagram in the command value calculator 52 and the constant calculator 45 in the control device 50 shown in FIG.

That is, the control method of the induction motor 2 shown in FIG. 19 is different from the control method shown in FIG. 17 in that the induction motor 2 has a direct current voltage (V _F ) corresponding to the induction voltage e _2DC0 as shown in FIG. First, a DC voltage (V _R ) having a polarity opposite to that of the V _F and having substantially the same amplitude is applied for a period of T _R (T _R <T ₀ ), and immediately after that, the DC voltage (V _F ) is applied. applying a by is to the time when the time T _R has passed the start point of the time T _0, by using this control method, the residual of the induction motor 2 when deriving the excitation inductance Lm of the induction motor 2 The influence of magnetic flux can be reduced.

  FIG. 20 is an operation waveform diagram showing an eighth embodiment of the method for controlling the induction motor according to the present invention. The command value calculator 42, the constant calculator 46, or FIG. 15 in the controller 40 shown in FIG. 6 is an operation waveform diagram in the command value calculator 52 and the constant calculator 46 in the control device 50 shown in FIG.

That is, the control method of the induction motor 2 shown in FIG. 20 is different from the control method shown in FIG. 18 in that the induction motor 2 has a direct current voltage (V _F ) corresponding to the induction voltage e _2DC0 as shown in FIG. First, a DC voltage (V _R ) having a polarity opposite to that of the V _F and having substantially the same amplitude is applied for a period of T _R (T _R <T ₀ ), and immediately after that, the DC voltage (V _F ) is applied. the applied the time T _R the time when a lapse T ₀ and t (1), is to have a starting point of t (2), by using this control method, the induction motor 2 excitation inductance Lm The influence of the residual magnetic flux of the induction motor 2 when deriving can be reduced.

The circuit block diagram of the control apparatus of the induction motor which shows 1st Embodiment of this invention Partial detailed circuit configuration diagram of FIG. Partial detailed circuit configuration diagram of FIG. The circuit block diagram of the control apparatus of the induction motor which shows 2nd Embodiment of this invention Partial detailed circuit configuration diagram of FIG. 1 and 4 are equivalent circuit diagrams of the induction motor for explaining the operation of FIG. Waveform diagram for explaining the operation of the first embodiment of the present invention Waveform diagram for explaining the operation of the second embodiment of the present invention Waveform diagram for explaining the operation of the third embodiment of the present invention. Waveform diagram for explaining the operation of the fourth embodiment of the present invention. Circuit diagram of induction motor control device showing conventional example The circuit block diagram of the control apparatus of the induction motor which shows the 3rd Embodiment of this invention Partial detailed circuit configuration diagram of FIG. Partial detailed circuit configuration diagram of FIG. The circuit block diagram of the control apparatus of the induction motor which shows 4th Embodiment of this invention FIG. 15 is a partial detailed circuit configuration diagram. Waveform diagram for explaining the operation of the fifth embodiment of the present invention. Waveform diagram for explaining the operation of the sixth embodiment of the present invention. Waveform diagram for explaining the operation of the seventh embodiment of the present invention Waveform diagram for explaining the operation of the eighth embodiment of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Inverter, 2 ... Induction motor, 3 ... Current detector, 10 ... Controller, 11 ... Command value calculator, 12 ... Integrator, 13, 14 ... Coordinate converter, 15 ... Constant calculator, 20 ... Controller DESCRIPTION OF SYMBOLS 21-23 ... Command value calculator, 24-27 ... Constant calculator, 30 ... Control device, 31-33 ... Command value calculator, 40 ... Control device, 41, 42 ... Command value calculator, 43-46 ... Constant calculator, 50... Control device, 51, 52 .. Command value calculator.

Claims (9)

Before normal operation of the induction motor, a DC voltage is generated from a power conversion device that drives the induction motor based on a voltage command value corresponding to a rated induced voltage value of the induction motor that is commanded to the induction motor. The excitation current of the induction motor is obtained by calculation based on the detected value of the current flowing in the induction motor at this time and the rated induced voltage value, and the excitation inductance of the induction motor is calculated based on the calculated excitation current value. And the calculated value of the excitation inductance is used as a motor constant in the variable speed control of the induction motor. In the control method of the induction motor according to claim 1 ,
A time T ₀ based on a value obtained by dividing the rated secondary magnetic flux value of the induction motor by the rated induced voltage value is calculated in advance;
From the detected current value of the motor when the time T ₀ after applying the DC voltage to the induction motor, the rated induced voltage value, and the secondary resistance value of the induction motor, the induction motor Deriving the calculated excitation current value,
The induction motor control value is based on a value obtained by dividing the rated secondary magnetic flux value by the excitation current calculation value. In the control method of the induction motor according to claim 1,
The induction motor of previously calculated time T _0, based on the value obtained by dividing the rated secondary magnetic flux value at the rated induced voltage value, N corresponding to the time T ₀ (N ≧ 1) number of time T ₁ , T ₂ ,... _TN (T ₁ <T ₂ <... <T _N <T ₀ )
A current detection value of the motor every time T ₁ , T ₂ ,... T _N , T ₀ after application of the DC voltage to the induction motor, and the rated induced voltage value ; Deriving the excitation current calculation value of the induction motor from the secondary resistance value of the induction motor,
The excitation inductance calculation value corresponds to the excitation corresponding to a value obtained by multiplying the rated secondary magnetic flux value by coefficients T ₁ / T ₀ , T ₂ / T ₀ ,... _TN / T ₀ , T ₀ / T _0. A control method for an induction motor, characterized in that it is based on respective values obtained by division calculation with current calculation values. In the control method of the induction motor according to claim 2 or 3 ,
Before applying the DC voltage (V _F ) to the induction motor, first, a DC voltage (V _R ) having a polarity opposite to that of the V _F and having substantially the same amplitude is applied for T _R (T _R <T ₀ ). The induction motor control method is characterized in that the DC voltage (V _F ) is applied immediately thereafter and the time T _R has elapsed is set as the starting point of the T ₀ . In the control method of the induction motor according to claim 2 or 3 ,
After the DC voltage (V _F ) is applied to the induction motor for the time T ₀ , a DC voltage (V _R ) having a polarity opposite to that of the V _F and an amplitude substantially equal to the voltage is applied for the time T ₀ ,
An average value of the excitation inductance calculation value at the DC voltage (V _F ) and the excitation inductance calculation value at the DC voltage (V _R ) is obtained, and this average value is set as a new excitation inductance calculation value of the induction motor. An induction motor control method characterized by the above. In the control method of the induction motor according to claim 1 ,
Calculated induced voltage computation value of the induction motor on the basis of the secondary resistance value of the detection value and the induction motor of the current flowing immediately after the previous SL DC voltage is applied to said induction motor to said induction motor,
From the induced voltage calculation value, the rated induced voltage value, and the rated secondary magnetic flux value of the induction motor, the secondary magnetic flux calculation value of the induction motor is obtained,
Obtaining the excitation current calculation value of the induction motor based on the detected value of the current flowing in the induction motor and the rated induced voltage value during the period in which the DC voltage is applied to the induction motor,
Obtaining the excitation inductance calculation value of the induction motor from the secondary magnetic flux calculation value and the excitation current calculation value,
A method for controlling an induction motor, wherein the calculated value of excitation inductance is used as a motor constant in variable speed control of the induction motor. In the control method of the induction motor according to claim 1 ,
Detection value and the respective current flowing through the induction motor at the start and end points of a predetermined interval during the period of pre-Symbol DC voltage is applied to the induction motor, the secondary resistance value of the induction motor Based on the induction voltage calculation value of the induction motor based on,
From the induced voltage calculation value, the rated induced voltage value, and the rated secondary magnetic flux value of the induction motor, obtain the secondary magnetic flux calculation value of the induction motor,
Obtaining the excitation current calculation value of the induction motor based on the detected value of the current flowing in the induction motor and the rated induced voltage value during the period in which the DC voltage is applied to the induction motor,
Obtaining the excitation inductance calculation value of the induction motor from the secondary magnetic flux calculation value and the excitation current calculation value,
A method for controlling an induction motor, wherein the calculated value of excitation inductance is used as a motor constant in variable speed control of the induction motor. In the control method of the induction motor according to claim 6 or 7 ,
A time T ₀ based on a value obtained by dividing the rated secondary magnetic flux value of the induction motor by the rated induced voltage value is calculated in advance;
From the detected current value of the motor when the time T ₀ after applying the DC voltage to the induction motor, the rated induced voltage value, and the secondary resistance value of the induction motor, the induction motor A method for controlling an induction motor, wherein an excitation current calculation value is derived. In the control method of the induction motor according to claim 8 ,
Before applying the DC voltage (V _F ) to the induction motor, first, a DC voltage (V _R ) having a polarity opposite to that of the V _F and having substantially the same amplitude is applied for T _R (T _R <T ₀ ). The induction motor control method is characterized in that the DC voltage (V _F ) is applied immediately thereafter and the time T _R has elapsed is set as the starting point of the T ₀ .

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