JP5537399B2 - Control device - Google Patents

Description

  The present invention relates to a speed sensorless vector control device for an induction motor.

  As a conventional control device for an induction motor, Japanese Patent Application Laid-Open No. 2005-45847 describes that a minute d-axis current is applied because a torque shock occurs when a large current is applied when the speed is unknown. However, in a low speed range where the speed electromotive force is small and easily affected by a voltage error, the speed electromotive force is increased by increasing the d-axis current and increasing the magnetic flux, thereby improving the speed estimation accuracy. That is, in the low speed range, a voltage compensation value obtained from the estimated speed value, the d-axis current command value, and the d-axis current detection value is applied to the d-axis voltage command value to increase the magnetic flux, and the initial value of the estimated speed This is to prevent the speed estimation accuracy from deteriorating because the magnetic flux decreases in the process where the estimated speed generated when the polarity of the actual speed and the polarity of the actual speed are different from each other.

JP 2005-45847 A

  In the induction motor control device shown as the prior art, a torque shock may occur in order to increase the magnetic flux by applying the voltage compensation value to the d-axis voltage command value in the low speed region.

  The problem of the present invention is that speed estimation accuracy does not deteriorate even if voltage compensation is not performed on the d-axis voltage command in the low speed range, and high speed estimation is possible in all speed ranges from the low speed range to the high speed range. It is to provide a control device for an electric motor.

  In order to solve the above-described problem, the present invention provides a second d-axis of the rotating coordinate system so that the detected d-axis current value of the rotating coordinate system approaches the first d-axis current command value of the rotating coordinate system. A d-axis current command generation unit that generates a current command value; and a second axis of the rotating coordinate system so that a q-axis current detection value of the rotating coordinate system approaches a first q-axis current command value of the rotating coordinate system. A voltage command for the power converter is generated based on a q-axis current command generation unit that generates a q-axis current command value, the second d-axis current command value, and the second q-axis current command value. A voltage vector calculation unit; a q-axis current detection value; and a speed estimation unit that generates a motor speed estimation value based on the second q-axis current command value.

  According to the present invention, it is possible to improve speed estimation accuracy in a low speed range or prevent deterioration of speed estimation accuracy without performing voltage compensation on the d-axis voltage command.

It is a block diagram of the control apparatus of the induction motor by the 1st Embodiment of this invention. It is a lineblock diagram of a rail car drive system provided with a control device of a 1st embodiment of the present invention. It is a block diagram of the d-axis current command calculating part in the 1st Embodiment of this invention. It is a block diagram of the q-axis current command calculating part in the 1st Embodiment of this invention. It is a block diagram of the speed estimation calculating part in the 1st Embodiment of this invention. It is a block diagram of the control apparatus of the induction motor by the 2nd Embodiment of this invention.

  The details of the present invention will be described below with reference to the drawings.

  The induction motor control apparatus of the present embodiment will be described with reference to FIGS.

  FIG. 2 shows a railway vehicle drive system to which the present invention is applied. The DC voltage received from the overhead line 201 and the track 202 via the current collector 203 and the wheel 204 is input to the power converter 206 provided with the power semiconductor switching element via the power receiving filter 205. The power receiving filter 205 includes a filter reactor 205a and a filter capacitor 205b.

Master controller unit 209 converts a notch operation of the motorman the notch command alpha ^*, enter the notch command alpha ^* to the current command generator 210. The current command generation unit 210 generates a first d-axis current command value I _d ^* and a first q-axis current command value I _q ^* based on the notch command α ^* , and this d-axis current command I _d ^*. And the q-axis current command I _q ^* are input to the vector control unit 211. The vector control unit 211 includes a d-axis current command I _d ^* , a q-axis current command I _q ^*, and three-phase current detection values I _u , I _v , Three-phase voltage commands V _u ^* , V _v ^* , V _w ^* are generated from I _w .

The power converter 206 converts the collected DC voltage into a variable voltage and a variable frequency AC voltage in accordance with the three-phase voltage commands V _u ^* , V _v ^* , and V _w ^* sent from the vector control unit 211. Then, the induction motor 208 is driven. The induction motor 208 generates torque by the AC voltage supplied from the power converter 206, and drives the wheels 204 via a gear (not shown).

  In addition, although one induction motor is illustrated in FIG. 2, a plurality of induction motors such as two or four may be driven.

  Next, a detailed configuration of the vector control unit 211 will be described with reference to FIG.

The coordinate conversion unit 1 converts the three-phase current detection values I _u , I _v and I _w into a d-axis current I _d and a q-axis current I _q based on the phase command θ ^* . The d-axis current command calculation unit 6 and the q-axis current command calculation unit 7 are configured such that the detected current values I _d and I _q are the first d-axis and q-axis current command values I _d ^* and I given from the host device. The second d-axis and q-axis current command values I _d ^** and I _q ^** are calculated so as to match _q ^* .

The voltage vector calculation unit 8 calculates the voltage command values V _d ^* and V _q ^* using the calculated current command values I _d ^** and I _q ^** , the power converter frequency command ω ₁ ^*, and the induction motor constant. Based on the phase command θ ^* , the coordinate conversion unit 9 converts the voltage commands V _d ^* , V _q ^* into three-phase voltage commands V _u ^* , V _v ^* , V _w ^* based on the phase command θ ^* , and converts the power command to the power converter. Control the output voltage.

The speed estimation calculation unit 2 sets the first d-axis current command value I _d ^* , the second q-axis current command value I _q ^** , the q-axis current detection value I _q, and the power converter frequency command value ω ₁ ^* . Based on this, the estimated speed value ω _r ^ is calculated.

The slip calculation unit 3 calculates a slip frequency command ω _s ^* based on the first d-axis current command value I _d ^* and the first q-axis current command value I _q ^* . By adding the estimated speed value omega _r ^ and the slip frequency command omega _s ^* by the adder 4, and generates a power converter frequency command omega ₁ ^*. Phase calculating unit 5 integrates the power converter frequency command omega ₁ ^*, to generate a phase command theta ^*.

  The above is the basic operation of the voltage control and the speed estimation calculation in the speed sensorless vector control device of the induction motor of the present invention.

Next, the configuration of the d-axis current command calculation unit 6 and the q-axis current command calculation unit 7 will be described with reference to FIGS. 3 and 4. FIG. 3 shows the configuration of the d-axis current command calculation unit 6. The deviation between the first d-axis current command value I _d ^* and the d-axis current detection value I _d given from the host device is multiplied by the integral gain K _id. Integration processing is performed, and the second d-axis current command value I _d ^** is output. FIG. 4 shows the configuration of the q-axis current command calculation unit 7, which is obtained by multiplying the deviation between the first q-axis current command value I _q ^* and the q-axis current detection value I _{q given from} the _{host device} by an integral gain K _iq. Integration processing is performed, and the second q-axis current command value I _q ^** is output. Here, the d-axis current command calculation unit 6 and the q-axis current command calculation unit 7 perform the integral calculation process, but can be replaced with a proportional or proportional + integral calculation.

  Next, a detailed configuration of the voltage vector calculation unit 8 will be described.

In the voltage vector calculation unit 8, the second d-axis current command value I _d ^** , the second q-axis current command value I _q ^**, and the motor constant are set as shown in the equations (1) and (2). The voltage command values V _d ^** and V _q ^** are calculated to control the power converter output voltage.

In equations (1) and (2), R ₁ ^* , L _σ ^* , M ^* , L ₂ ^* , ω ₁ ^* , T ₂ , and s are the primary resistance setting value and leakage inductance setting value of induction motor 208, respectively. , Mutual inductance setting value, secondary inductance setting value, power converter frequency command value, secondary time constant, differential operator.

In addition, in the calculation of the voltage related to the time differentiation of the second d-axis current command value I _d ^** and the second q-axis current command value I _q ^** , the second current command value is the first current command value. And the deviation of the detected current value are calculated by integration processing, so that the integration of the d-axis current command calculation unit 6 and the q-axis current command calculation unit 7 and the differential operators of the equations (1) and (2) It is clear that the output is canceled and the output signal can be prevented from diverging to ± ∞ in the differential operation, so that the control operation can be executed stably. The second term in parentheses in the first term of the equation (1), the differential operation of the d-axis current command value I _d ^** in the third term in the equation (1), and the second item in the parenthesis of the first term in the equation (2). The differential calculation of the q-axis current command value I _q ^** of 2 terms was ignored in the conventional control, but in this application, by controlling these terms, it is possible to control with high accuracy even in a transient state. Can do. For the speed electromotive force term of the third term in the equation (2), since the d-axis current command is normally constant in the conventional control, the d-axis magnetic flux command value φ _d ^* is handled as constant. In the present application, since the fluctuation of the d-axis magnetic flux command value can be controlled with high accuracy by the second d-axis current command value I _d ^** , the control can be stably performed. In this way, when the current command value is calculated in the first stage and the voltage vector is calculated in the second stage based on the current command value, the motor current is made to match the current command value. The output voltage is controlled with high accuracy and high-precision control can be realized.

  Next, a detailed configuration of the speed estimation calculation unit 2 will be described with reference to FIG.

The q-axis voltage equation of the induction motor is as shown in Equation (3). For speed estimation, the speed electromotive force of the motor proportional to the speed ω _r and the d-axis magnetic flux φ _{d in} the third term on the right side is used. To do. Therefore, in order to estimate the speed with high accuracy, it is necessary that the speed ω _r and the d-axis magnetic flux φ _d are sufficiently large values and current detection can be performed with high accuracy. However, since the speed ω _r can vary in the range from near zero to the maximum speed depending on the driving state of the vehicle, the second d-axis current command value is used to perform speed estimation with high accuracy without depending on the speed. Based on the above, it is necessary to obtain a sufficiently large speed electromotive force by controlling the d-axis magnetic flux φ _d required for the operation of the motor with high accuracy by performing the d-axis voltage vector calculation.

The speed estimation calculation unit 2 uses the q-axis current detection value, the second q-axis current command value I _q ^** , the power converter frequency command ω ₁ ^*, and the motor constant as shown in Equation (4). Thus, the estimated speed value ω _r ^ is calculated. In equation (4), the first term in parentheses is the q-axis current command value proportional voltage calculation unit 501, the second term in parentheses is the q-axis current detection value proportional voltage calculation unit 503, and the third term is the q-axis current command value. This corresponds to the time differential voltage calculation unit 502. The gain K _alpha, may be adjusted at a value of 0 or more as desired velocity estimation performance.

  Further, since the second q-axis current command value is calculated by integrating the deviation between the first q-axis current command value and the q-axis current detection value, the integration and current of the q-axis current command calculation unit 7 are calculated. It is clear that the differentiation of the command value time differential voltage calculation unit 502 cancels, and the output signal of the q-axis current command value time differential voltage calculation unit 502 can be avoided to diverge to ± ∞. Can be executed.

In the speed estimation calculation, when the speed estimated value ω _r ^ and the actual speed ω _r do not match, the power converter frequency command ω, which is an addition value of the speed estimated value ω _r ^ and the slip frequency command ω _s ^* _{Since the} phase command θ ^* calculated by integrating ₁ ^* has a value including an error, the detected current values I _d and I _{q of the} d-axis and the q-axis calculated based on the phase command θ ^* also have an error. The output voltage is controlled by the d-axis current command calculation unit 6, the q-axis current command calculation unit 7, and the voltage vector calculation unit 8 so that the motor current matches the current command value. With this control, when the motor current matches the current command value, the power converter frequency command ω ₁ ^* and the slip frequency command ω _s ^* are accurately calculated, and the phase command θ ^* matches the phase of the motor. As a result, the estimated speed value ω _rと matches the actual speed ω _r .

By the way, in a railway vehicle, for example, when starting an electric power converter from an initial speed ω _r = 0 in a stopped state, when starting up from a state of retreating on an uphill, that is, starting from a negative initial speed ω _r <0, Since the power converter is stopped during coasting for the purpose of reducing the loss of the converter, there is a case where the power converter is restarted from a positive initial speed ω _r > 0. At these startups, in order to avoid torque shock, it is necessary to quickly match the estimated speed value ω _r ^ to the actual speed ω _r in the estimation of a wide range of initial speeds from the low speed range including the negative speed to the high speed range. . Therefore, a case where such an initial speed is estimated will be described.

At the time of initial speed estimation, control is not performed in a stopped, reverse, or coasting state. Therefore, when starting the power converter to estimate the speed, the first q-axis current command value I _q ^* = 0 And
At this time, since the slip frequency command ω _s ^* = 0, the power converter frequency command ω ₁ ^* = ω _r ＋+ ω _s ^* coincides with the speed estimated value ω _r ＾. The q-axis current detection value I _q is equal to the first q-axis current command value so that the d-axis current detection value matches the first d-axis current command value I _d ^* (current value necessary for the operation of the motor). When the output voltage is controlled so as to match the value I _q ^* = 0, the second q-axis current command I _q ^** = 0 and the q-axis current detection value I _q = 0, so that the speed estimation calculation The speed estimated value ω _r ^ which is the output of the unit 2 can be made to coincide with the actual speed ω _r . Further, if the output voltage is controlled so that the current becomes I _d = I _d ^* , I _q = I _q ^* = 0, and as a result, the magnetic flux converges to φ _d = φ _d ^* , φ _q = 0, Since a torque shock does not occur in principle, it is not necessary to give a minute current value to the first d-axis current command value I _d ^* . Here, although an initial value is not set for ω ₁ ^* , the speed estimation time can be shortened by giving a positive value between the speed ranges in which speed estimation is performed as an initial value.

As described above, the estimated speed ω _r ^ converges to the actual speed ω _r regardless of the polarity of the speed, and the speed can be estimated.

  FIG. 6 shows a second embodiment of the present invention.

Example 2 is an example in which a part of the configuration of the vector control unit 211 shown in FIG. 2 is different from Example 1, and the first d-axis and q-axis current command values I _d ^* , I _q ^* , The second d-axis and q-axis current command values I _d ^*** and I _q ^*** are calculated by adding the output values I _d ^** and I _q ^** of the current command calculation units 6 and 7. It is a method. In FIG. 6, 1 to 9 are the same as those in FIG. 10 is an adder that adds the first d-axis current command value I _d ^* and the output value I _d ^{** of the} d-axis current command calculation unit 6, and 11 is the first q-axis current command value I _q ^*. And an output value I _q ^{** of the} q-axis current command calculation unit 7.

In this embodiment, the current command value is basically supplied by I _d ^* and I _q ^* . Considering that I _d ^* and I _d , and I _q ^* and I _q match each other, it is clear that the operation is the same as in the above-described embodiment, and the same effect can be obtained. In addition, when the control calculation cycle is long, the control gain cannot be increased and high response cannot be realized. However, the responsiveness can be improved by performing the feedforward control as in this embodiment. become.

DESCRIPTION OF SYMBOLS 1 Coordinate conversion part 2 Speed estimation calculating part 3 Slip calculating part 4, 10, 11 Adder 5 Phase calculating part 6 d-axis current command calculating part 7 q-axis current command calculating part 8 Voltage vector calculating part 9 Coordinate converting part 201 Overhead line 202 Track 203 Current collector 204 Wheel 205 Power receiving filter 205a Filter reactor 205b Filter capacitor 206 Power converter 207 Current detector 208 Induction motor 209 Main controller 209 Current command generator 211 Vector controller 501 q-axis current command value proportional voltage calculator 502 q-axis current command value time differential voltage calculation unit 503 q-axis current detection value proportional voltage calculation unit 504 frequency calculation unit

Claims (5)

In a control device that controls the output voltage of a power converter that drives an electric motor,
A d-axis current command generation unit that generates a second d-axis current command value of the rotating coordinate system so that the d-axis current detection value of the rotating coordinate system approaches the first d-axis current command value of the rotating coordinate system. When,
A q-axis current command generation unit that generates a second q-axis current command value of the rotating coordinate system so that the q-axis current detection value of the rotating coordinate system approaches the first q-axis current command value of the rotating coordinate system. When,
A voltage vector calculation unit that generates a voltage command for the power converter based on the second d-axis current command value and the second q-axis current command value;
A speed estimation unit that generates an estimated speed value of the electric motor based on the q-axis current detection value and the second q-axis current command value ;
The speed estimator calculates using the q-axis current detection value, the second q-axis current command value, the time change rate of the second q-axis current command value, and a power converter frequency command. By doing so, the speed estimated value of the said electric motor is produced | generated . The control device according to claim 1,
The voltage vector calculation unit includes the second d-axis current command value, a time change rate of the second d-axis current command value, the second q-axis current command value, and the second q-axis. A control device that generates a voltage command for the power converter by calculating using a time change rate of a current command value . In a control device that controls the output voltage of a power converter that drives an electric motor,
A d-axis current command generation unit that generates a second d-axis current command value of the rotating coordinate system so that the d-axis current detection value of the rotating coordinate system approaches the first d-axis current command value of the rotating coordinate system. When,
A q-axis current command generation unit that generates a second q-axis current command value of the rotating coordinate system so that the q-axis current detection value of the rotating coordinate system approaches the first q-axis current command value of the rotating coordinate system. When,
The second d-axis current command value, the second q-axis current command value, the time change rate of the second d-axis current command value, and the time change rate of the second q-axis current command value A voltage vector calculation unit that generates a voltage command of the power converter by calculating a secondary magnetic flux command value of the d-axis based on a current command value of the second d-axis,
A speed estimation unit that generates a speed estimation value of the electric motor based on the q-axis current detection value and the second q-axis current command value;
The speed estimator calculates using the q-axis current detection value, the second q-axis current command value, the time change rate of the second q-axis current command value, and a power converter frequency command. By doing so, the speed estimated value of the said electric motor is produced | generated. The control apparatus according to claim 3 Symbol mounting,
The voltage vector calculation unit includes the second d- axis current command value, a time change rate of the second d- axis current command value, the second q-axis current command value, and the second q-axis. A control device that generates a voltage command for the power converter by calculating using a time change rate of a current command value.   5. A control device according to claim 1, a power converter controlled by the control device, and an induction motor driven by the power converter, wherein a wheel is driven by the induction motor. Traveling
  An electric vehicle characterized by.

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