JP3299416B2 - Vector control method of induction motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a vector control method for an induction motor, and more particularly to a method for measuring a primary resistance of an induction motor.

[0002]

2. Description of the Related Art In a vector control method, constants of an equivalent circuit must be accurately set in order to control an equivalent circuit of an induction motor as a control model.

[0003]

Therefore, there is a function for automatically adjusting the primary resistance. However, in the conventional technology, the U phase
A voltage was applied between the V phases or between the V and W phases or between the W and U phases, and the resistance was measured from the current flowing therethrough. Therefore, accurate adjustment could not be performed if the primary resistance of each phase varied. When an appropriate voltage is applied, an overcurrent may flow. Further, in order to prevent an overcurrent from flowing and to cope with a variation in the primary resistance, the voltage applied between the U phase and the V phase, between the V phase and the W phase, and between the W phase and the U phase is controlled by the current. , hours to current control by noise or the like
And automatic adjustment took time.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a vector control method of an induction motor that can automatically adjust a primary resistance in a short time without flowing an overcurrent.

[0005]

According to the first aspect of the present invention, a primary frequency and a voltage are controlled by an exciting current and a torque current detected from a primary current of an induction motor, and a primary resistance is controlled. The exciting component voltage is obtained from the value obtained by multiplying the set value of the exciting current and the primary frequency, and the multiplied value obtained by multiplying the set value of the primary resistance by the torque current, the magnetic flux command value and In the vector control method of the induction motor, a torque component voltage is obtained from the multiplied value obtained by multiplying the primary frequency, and the command voltage of the voltage type inverter is obtained from the excitation component voltage and the torque component voltage. Of the windings, a period during which a current flows between the first phase, a period during which the current flows between the second phase, and a period during which the current flows between the third phase are sequentially set. Set in advance during the flowing period Performs current measurement with determining the voltage applied to the induction motor while the current control such that the current flowing in the flow matches during the second phase, the duration of each passing a current between the third phase between the first phase The current is measured while applying the applied voltage determined during the current flowing period to the induction motor,
It is characterized in that the set value of the primary resistance is adjusted from the average value of the measured current and the applied voltage during these periods, and the primary resistance can be automatically adjusted in a short time without flowing an overcurrent.

According to a second aspect of the present invention, in the first aspect of the present invention, the primary resistance value is not adjusted unless the average value of the measured current is within the matching width of the set current value when the primary resistance value is adjusted. There is no erroneous adjustment when automatically adjusting the primary resistance.

[0007]

Voltage equation of the embodiment of the invention] induction motor, given by equation (1) in an orthogonal coordinate system that rotates at the secondary interlinkage flux angular frequency (primary frequency) omega (hereinafter referred to as d-q coordinate system) Can be

[0008]

(Equation 1)

In the equation (1), r ₁ and r ₂ are the primary and secondary resistances of the induction motor, respectively, L ₁ and L ₂ are the primary and secondary inductances including the leakage inductance, and M is Mutual inductance between primary winding and secondary winding
The wardrobe values, the σ is _{^{1-M 2 / (L 1}} L 2) becomes leakage factor, .omega.s is a slip angular frequency, p is the d / dt becomes a differential operator, V _1d, V _1q are each primary voltage The d-axis and q-axis components, i _1d and i _1q are the d-axis and q-axis components of the primary current, ie, the exciting current and the torque current, and φ _2d and φ _2q are the d-axis and q of the secondary interlinkage flux, respectively. Represents the axis component.

[0010] The secondary flux linkage can be expressed as follows. φ _2d = Mi _1d + L ₂ i _2d φ _2q = Mi _1q q + L ₂ i _2q (2) i _2d and i _2q indicate the d-axis and q-axis components of the secondary current, respectively. Vector control means φ _2d = Mi _1d (constant), φ _2q
The primary voltage or the primary current is controlled so that = 0. If this condition is satisfied, the slip angular frequency ωs is given by equation (3).

[0011]

(Equation 2)

(3) In the voltage-type inverter, in a steady state (the differential term is zero), φ _2d = Mi _1d (constant) and φ _2q = 0 are substituted into equation (1) and given by equation (4). It can be realized by applying a given voltage.

[0013]

[Equation 3]

(4) However, in the transient state, an error term due to the differential term appears, and the slip angular frequency ωs becomes as shown in equation (5).

[0015]

(Equation 4)

(5) This is obtained by substituting equation (4) into equation (6) obtained by transforming equation (1) into a state equation and solving for ωs.

[0017]

(Equation 5)

(6) l ₁ , l ₂ = primary and secondary leakage inductance r ₂ ′ = r ₂ (M / L ₂ ) ² l ₂ ′ = l ₂ M / L ₂ Next, FIG. An operation performed by the vector operation device 1 based on the circuit of the embodiment shown in FIG. Vector processor 1 to multiplication setting value of the excitation current command i _1d ^* and primary resistance r _1, further current control compensation value .DELTA.i _1d of the excitation current i _1d obtained by subtracting from the exciting current command i _1d ^* adds a value obtained through vessel 1 _2, leakage factor σ primary Lee from the added value
Those multiplied by the multiplier 1 ₃ multiplication values? L ₁ of inductance L ₁ and the primary frequency omega, obtains the excitation-related voltage V _1d ^* by subtracting. Vector operation unit 1 first primary inductance L ₁ and by multiplying the excitation current command determining the excitation command value phi. Next, the torque current value i _1q and the primary resistance r
And multiplied by the _first set value, it obtains a torque portion voltage V _1q ^* by adding the one obtained by multiplying a magnetic flux command value φ and the primary frequency ω in the multiplier 1 _1. The coordinate converter 3 has a PW
Where obtaining the three-phase output voltages of the M control of the inverter 2 performs operations such as (7), performs seek primary voltage V _1, also this primary voltage V _1, the operation from the primary frequency omega, 3 Find the output voltage of the phase.

[0019]

(Equation 6)

.. (7) More specifically, the vector operation device 1 determines that φ _2d = Mi
_1d (constant), the d-axis and q-axis components V _1d ^* and V _1q ^* of the primary voltage are calculated from the excitation current command i _1d ^* , the torque current i _1q, and the primary frequency ω so that φ _2q = 0 (3) Is calculated by The coordinate converter 3 converts the voltages V _1d ^* and V _1q ^* from the vector operation device 1 into the phase angle command θ of the secondary linkage flux vector.
The inverter 2 is composed of a PWM inverter that controls the voltage applied to the induction motor 4 by the voltages Vu ^* , Vv ^* , Vw ^* from the coordinate converter 3, and the induction motor 4 is an inverter. 2 is speed controlled. The current detector 5 detects the phase current i of the induction motor 4.
u, iv, and iw are detected. The coordinate converter 6 converts the phase currents iu, iv, iw into a rotating coordinate system according to the phase angle command θ of the secondary flux linkage vector, and outputs an excitation current i _1d and a torque current i _1q . The delay circuit 7 has a torque current i _1q
And outputs a delayed torque current i _1q ′. The multiplier 8 multiplies the delay torque current i _1q ′ by the slip constant (Km) and outputs a slip angular frequency ωs. The adder 9 adds the rotational speed ωr ^* to the slip angular frequency ωs to obtain a primary frequency ω
Is output. The integrator 10 integrates the primary frequency ω and outputs a phase angle command θ of the secondary flux linkage vector. Multiplier 1
Reference numeral ₁ designates a magnetic flux command value φ obtained by multiplying the primary inductance L ₁ and the exciting current command i _1d ^* as an initial value. The magnetic flux command value φ is multiplied by the primary frequency ω and output.

The delay circuit 7 is composed of a subtractor 7 ₁ and a controller 7 _{2. The} subtracter 7 ₁ outputs a difference between the torque current i _1q and the delayed torque current i _1q ′ to the controller 7 ₂ for controlling. bowl 7 ₂ outputs a delayed torque current i _1q 'as the difference becomes zero, for example, a proportional-integral control. The embodiments of the present invention for automatically adjusting the primary resistance r ₁ value to be used in the above vector control will be described with reference to FIG. The configuration shown in FIG. 1 is provided alongside the overall configuration of FIG. 2 and is used at the time of measuring the primary resistance.

The command voltage calculator 11 shown in FIG. 1 calculates the command voltage V by proportional / integral control from the deviation between the set current and the U-phase current, and changes the phase in which the current flows to the commander 12 at the next stage. And a control unit that outputs a signal together with a signal for
2 has a function of storing a command voltage, determines a phase and a voltage to be applied, and determines a phase and a voltage to be applied.
, The commands Vu ^* , Vv ^* , Vw ^* of the voltage to be applied. Inverter 2 receives commands Vu ^* , Vv ^* , Vw
PWM control of the induction motor 4 is performed based on ^* . Detector 5
Is composed of the detector shown in FIG. 1 and outputs the detected current to the primary resistance calculating unit 13 when measuring the primary resistance,
The detected current of the U phase is subtracted from the set current and sent to the subtractor 14 to obtain a deviation. The primary resistance calculation unit 13 calculates a value of the primary resistance r ₁ from the detected current value and the voltage applied to the winding of the induction motor 4, and calculates and obtains the value of the primary resistance r ₁ from the storage function of storing the detected current value from the detector 5. The value of the primary resistance r ₁ is set in the primary resistance setting device 15.

The primary resistance setting device 15 is intended to be incorporated in the vector arithmetic unit 1 of FIG. 2, it is shown as a primary resistance r ₁ in FIG. 1. Next, a description will be given of adjustment of the primary resistance r _1. First, as shown in FIGS.
In Lu, CLv, and CLw, a current flows between the U phase and the W phase, a B period flows a current between the U phase and the V phase, and a current flows between the W phase and the V phase. A period C to be set is set. Here, between the A phase performs current control, B period, C
Period applies a voltage determined between A phase. In other words, in the period A, the command voltage calculation unit 11 gives the command unit 12 a signal indicating the command voltage V and the phase in which the current flows so that the current flows between the U phase and the W phase. Based on the command voltage V and the signal indicating the phase in which the current flows, the command device 12 gives a command of the applied voltage to the inverter 2, in this case, Vu ^* , Vw ^* , and the inverter 2 receives the command Vu ^* , Vw ^* . To apply a voltage to the corresponding windings CLu and CLw. Here the detector 5
Is subtracted by the subtractor 14 from the U-phase current and the set current, and the command voltage calculator 11 sets the absolute value of the difference between the U-phase current and the set current in advance as shown in FIG. It is detected whether or not there is a continuous Ta time within the current matching width X, and a matching signal is output to the commander 12 when it is determined that the matching has occurred. The command device 12 outputs the command voltage V at that time.
Is stored, and a signal is given to the primary resistance calculating unit 13. Upon receiving this signal, the primary resistance calculating unit 13 measures the U-phase current a plurality of times based on the detection output of the U-phase current from the detector 5 and stores the measured value. The W-phase current at this time is the same as the value of the U-phase current as shown in FIG. When the measurement is completed, the primary resistance calculating section 13 outputs a measurement end signal to the command device 12. The commander 12 gives commands Vu ^* and Vv ^* for applying a voltage based on the stored command voltage V between the U-phase and the V-phase to the inverter 2. To apply a voltage to flow a current. That is, the process shifts to the period B.

In the period B, the commander 14 outputs a signal to the primary resistance calculator 13 when the time Tb has elapsed, and the primary resistance calculator 13 detects the U-phase current from the detector 5 in the same manner as described above. The current is measured a plurality of times and the measured value is stored. Note that the value is the same as the value of the U-phase current as indicated by the V-phase current ha4 (b) at this time. When the measurement is completed, the primary resistance calculating section 13 outputs a measurement end signal to the command device 12. The command device 12 outputs a voltage based on the stored command voltage V to the W phase-
Commands Vw ^* and Vv ^* to be applied between the V phases are given to the inverter 2, and the inverter 2 thereby performs the W-phase to V-phase winding CL.
A voltage is applied to w and CLv to flow a current. That is, the process proceeds to the period C.

In the period C, the command unit 14 outputs T
After the elapse of the time b, a signal is output to the primary resistance calculation unit 13, and the primary resistance calculation unit 13 measures the W-phase current a plurality of times based on the detection output of the W-phase current from the detector 5, and stores the measured value. Note that the value is the same as the value of the U-phase current as indicated by the V-phase current ha4 (b) at this time. When this measurement is completed, the output is stopped.

Next, the primary resistance calculation unit 13 calculates the U-phase current, which is measured a plurality of times in the periods A, B, and C, by the calculation function .
The primary resistance r ₁ is calculated from the average value of the V-phase current and the W-phase current and the applied voltage, and is set in the primary resistance setting device 15. Here, A period between B phase, was measured the plurality of times of period C
The average value of the current of each phase is the current matching width X with respect to the set current.
If not within the set of primary resistance r ₁ is not performed.
The stop primary resistance r ₁ of the adjustment operation by stopping the output of the inverter 2 when the number times the current setting current flows during measurement.

Although the description has been made with reference to the phase to which the voltage is applied and the phase to which the current flows, the same can be done by changing the phase.

[0028]

According to the first aspect of the present invention, the primary frequency and the voltage are controlled by the exciting current and the torque current detected from the primary current of the induction motor, and the set value of the primary resistance is multiplied by the exciting current and the primary frequency. The excitation component voltage is obtained from the value obtained by the above, the multiplication value obtained by multiplying the set value of the primary resistance by the torque current, and the multiplication value obtained by multiplying the magnetic flux command value and the primary frequency are obtained. In the vector control method of the induction motor, which obtains the command voltage of the voltage-type inverter from the excitation voltage and the torque voltage, a current is applied between the first phase of the windings of each phase of the induction motor. A current flowing period, a current flowing period between the second phases, and a current flowing period between the third phases are sequentially set, and during the current flowing between the first phases, the current flowing to the preset current matches. Current control so that While current measurement with determining the voltage applied to the induction motor, during the second phase, the in the period of each passing a current between the third phase induction motor applied voltage determined by the period of time in which current is supplied between the first phase The current is measured while the voltage is being applied, and the set value of the primary resistance is adjusted based on the average value of the measured current and the applied voltage during these periods, so the primary resistance can be automatically adjusted in a short time without flowing overcurrent. There is an effect that can be.

According to a second aspect of the present invention, in the first aspect of the present invention, when the primary resistance value is adjusted, the primary resistance value is not adjusted unless the average value of the measured current is within the matching width of the set current value. There is an effect that erroneous adjustment is not performed when automatically adjusting.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part of an embodiment of the present invention.

FIG. 2 is a system configuration diagram of an induction motor vector control device used in an embodiment of the present invention.

FIG. 3 is an explanatory diagram of an operation of flowing through a winding of the induction motor according to the first embodiment.

FIG. 4 is an explanatory diagram of an operation of a current flowing through a winding of the induction motor according to the first embodiment.

[Explanation of symbols]

2 Inverter 4 Induction motor 5 Detector 11 Command voltage calculator 12 Commander 13 Primary resistance calculator 14 Subtractor 15 Primary resistance measuring instrument V Command voltage Vu ^* , Vv ^* , Vw ^* command r ₁ Primary resistance

Continuation of the front page (56) References JP-A-8-33194 (JP, A) JP-A-7-143800 (JP, A) JP-A-1-136596 (JP, A) JP-A-6-222118 (JP) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H02P 21/00 H02P 5/41 302

Claims (2)

(57) [Claims] A primary frequency and a voltage are controlled by an exciting current and a torque current detected from a primary current of an induction motor, and a primary resistance set value is multiplied by a value obtained by multiplying the exciting current by the primary frequency. A multiplied value obtained by multiplying the excitation component voltage by the set value of the primary resistance and the torque current,
Obtaining the torque portion voltage and a multiplied value obtained by multiplying the magnetic flux command value and the primary frequency, Oite the vector control method for an induction motor from these exciting component voltage and the torque portion voltage to obtain a command voltage of the voltage-type inverter Among the windings of each phase of the induction motor, a period in which current flows between the first phase, a period in which current flows in the second phase, and a period in which current flows in the third phase are sequentially set. In the period during which the current flows between the phases, the applied voltage of the induction motor is determined and the current is measured while controlling the current so that the current flowing to the preset current matches, and the current is measured between the second phase and the third phase. In each of the periods, the current is measured while applying the applied voltage determined during the period in which the current flows between the first phases to the induction motor, and the average value of the measured current and the applied voltage during these periods are used to determine the primary resistance. Adjusting the set value Vector control method for an induction motor according to symptoms. 2. The induction motor according to claim 1, wherein, when adjusting the primary resistance, the set value of the primary resistance is not adjusted unless the average value of the measured currents is within the matching width of the set current value. Vector control method.