JP2008043112A - Induction machine controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that, in a batch control of a plurality of induction machines, errors are caused to occur in the calculation of the speed of the induction machines, actual slipping of the induction machines expands, and the induction machines fall into a step-out state, if speed difference between the induction machines is large. <P>SOLUTION: A magnetic flux amount calculation device, which calculates the magnitude of the magnetic flux of the induction machines from induction machine magnetic flux, a magnetic flux error calculation device, which inputs the magnitude of the induction machine magnetic flux and a magnetic flux reference value and outputs an error rate, an integrator that integrates the error rate and outputs an error period of time, a comparator, which compares a time set value with the error period of time and outputs a detection signal, and an operation logic device, which creates a control command from the operation command and the detection signal, are newly added. The control command instead of the operation command is inputted into a torque control means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to torque control of induction machines, and in particular, avoids a step-out state during collective torque control of a plurality of induction machines.

FIG. 2 is a block diagram showing a conventional example. 101, 102, 103 and 104 are induction machines, 2 is a current detector, 3 is a power converter, 4 is torque control means, 5 is a magnetic flux calculator, and 6 is a speed calculator.
In FIG. 2, only four induction machines are shown, but any number of induction machines may be used as long as there are a plurality of induction machines. Hereinafter, description will be made assuming that there are four induction machines.

The current detector 2 detects a total current i that is a sum of currents flowing through the individual induction machines connected to the power converter 3 for each phase.
The voltage system magnetic flux calculator 5 calculates the induction machine magnetic flux φ from the total current i and the voltage command v input to the power converter 3 by the equation (1).

ここで、Ｒ１は全誘導機の一次抵抗合成値、Ｌ２は二次自己インダクタンス合成値、Ｍは相互インダクタンス合成値、Lekは漏れインダクタンス合成値である。漏れインダクタンス合成値Lekは、

Here, R1 is a primary resistance composite value of all induction machines, L2 is a secondary self-inductance composite value, M is a mutual inductance composite value, and Lek is a leakage inductance composite value. Leakage inductance composite value Lek is

で与えられる。ここで、Ｌ１は全誘導機の一次自己インダクタンス合成値である。

Given in. Here, L1 is a primary self-inductance composite value of all induction machines.

  The speed calculator 6 calculates the induction machine speed ωm from the total current i and the induction machine magnetic flux φ using the equations (3) to (5).

ここで、Ｒ２は全誘導機の二次抵抗合成値、ＦＡとＦＢは誘導機磁束φの成分である。

Here, R2 is a secondary resistance composite value of all induction machines, and FA and FB are components of induction machine magnetic flux φ.

The induction machine speed ωm calculated by Expression (5) is an average value of the individual induction machine speeds, and is a value expressed by Expression (6).
ωm = (ωm1 + ωm2 + ωm3 + ωm4) / 4 Formula (6)
Here, ωm1 is the speed of the induction machine 101, ωm2 is the speed of the induction machine 102, ωm3 is the speed of the induction machine 103, and ωm4 is the speed of the induction machine 104.

When the operation command N is ON, the torque control means 4 is based on the induction machine speed ωm and the total current i so that the magnetic flux and total torque of all induction machines become the flux command φ * and the torque command τ *. Command v is output. When the operation command N is OFF, the voltage command v is set to 0, and the induction machine is brought into an uncontrolled state.
The power converter 3 amplifies the voltage command v and supplies power to the induction machines 101 to 104 that are loads.

  The operation command N is input to the power converter 3 instead of being input to the torque control means 4, and when the operation command N is ON, power corresponding to the voltage command v is supplied to the induction machines 101 to 104, and the operation command N is OFF. Even when the power supply is stopped, the same function can be obtained.

  With the above configuration, when the operation command is ON, the total torque of the plurality of induction machines can be controlled to the torque command τ *. If the operation command is turned off, the plurality of induction machines can be brought into an uncontrolled state.

  In vehicles, since bogie control and vehicle control are common, collective torque control of multiple induction machines is frequently used.

Japanese Patent Application Laid-Open No. 11-069895

The prior art has the following problems.
When some wheel shafts that are collectively controlled in the vehicle are idle, for example, when the speed ωm3 of the induction machine 103 is larger than ωm1, ωm2, and ωm4, according to equation (6), ωm1, ωm2, ωm3, A calculation error of the induction machine speed ωm with respect to ωm4 occurs. If the idler of the induction machine 103 is large and the calculation error of the induction machine speed ωm is large, the induction machine 103 is out of step. Furthermore, if the idling of the induction machine 103 becomes large, not only the induction machine 103 but also the induction machine 101, the induction machine 102, and the induction machine 104 will be out of step.

  In addition, when the sliding of some wheel shafts becomes large, the induction machine may be out of step as in the case of idling.

When the induction machine goes out of step, torque control becomes impossible, and in the worst case, overcurrent and overvoltage lead to destruction of the induction machine and power converter element.
The present invention has been made to solve the above problems.

  In order to solve the above-described problems, in claim 1, a magnetic flux amount calculator 7 for calculating the induction machine magnetic flux magnitude φvol from the induction machine magnetic flux φ, the induction machine magnetic flux magnitude φvol and the magnetic flux reference value φn are input. A magnetic flux error calculator 8 for outputting the error rate dφ, an integrator 9 for integrating the error rate dφ and outputting the error time Tφ, and a comparator for comparing the time set value Tn and the error time Tφ and outputting the detection signal K. 10 and a new operation logic unit 11 for generating a control command NN from the operation command N and the detection signal K is added, and the control command NN is input to the torque control means 4 instead of the operation command N.

In claims 2 to 4, an arithmetic expression of the magnetic flux error calculator 8 is configured.
According to the fifth aspect of the present invention, the magnetic flux reference value φn is created by the reference value setter 12 which receives the magnetic flux command φ *. In claim 6, the magnetic flux reference value φn is the product of the magnetic flux command φ * and the attenuation factor β.

Before the induction machine is out of step, it can be detected that some of the wheel shafts are idling and sliding, and torque control of the induction machine can be stopped.
Depending on the degree of idling and sliding of some wheel shafts, the time until detection can be changed.

  By newly adding a magnetic flux amount calculator 7, a magnetic flux error calculator 8, an integrator 9, and a comparator 10, it can be detected that idling or sliding has occurred on some wheel shafts in all induction machines. Further, depending on the calculation contents of the magnetic flux error calculator 8, it is possible to change the time until detection with respect to the degree of idling and sliding of some wheel shafts. The detected logic is processed by the driving logic unit 11 to create a control command and input it to the torque control means 4 to stop the torque control of the induction machine.

  FIG. 1 is a block diagram showing an embodiment of the present invention, wherein 7 is a magnetic flux amount calculator, 8 is a magnetic flux error calculator, 9 is an integrator, 10 is a comparator, and 11 is an operation logic unit.

  The magnetic flux amount calculator 7 receives the induction machine magnetic flux φ and calculates the induction machine magnetic flux magnitude φvol from the equation (7).

The magnetic flux error calculator 8 receives the induction machine magnetic flux magnitude φvol and the magnetic flux reference value φn, and outputs an error rate dφ. In the magnetic flux error calculator 8, an error rate dφ that satisfies the following three points is calculated from the induction machine magnetic flux magnitude φvol.
・ Dφ should be a dimensionless unit.
• dφ = 0 at φvol = φn.
・ If φvol <φn, dφ ≧ 0. In particular, when φvol = 0, dφ> 0.

  The integrator 9 integrates the error rate dφ to obtain an error time Tφ. However, the error time Tφ is 0 or more, and less than 0 is 0. The comparator 10 receives the error time Tφ and the time set value Tn, turns the detection signal K ON when Tφ <Tn, and turns OFF the detection signal K when Tφ> Tn.

  When the magnetic flux magnitude φvol becomes smaller than the magnetic flux reference value φn by combining the magnetic flux error calculator 8, the integrator 9, and the comparator 10, the detection signal K changes from ON to OFF after elapse of time depending on the time set value Tn. And switch.

  The operation logic unit 11 performs an AND operation between the operation command N and the detection signal K, and outputs a control command NN. If either the operation command N or the detection signal K is OFF, the control command NN is OFF.

  When the control command NN is ON, the torque control means 4 is based on the induction machine speed ωm and the total current i so that the magnetic flux and total torque of all induction machines become the flux command φ * and the torque command τ *. Command v is output. When the control command NN is OFF, the voltage command v is set to 0, and the induction machine is brought into a non-control state.

  The control command NN is input to the power converter 3 instead of being input to the torque control means 4, and when the control command NN is ON, power corresponding to the voltage command v is supplied to the induction machines 101 to 104, and the control command NN is OFF. Even when the power supply is stopped, the same function can be obtained.

  It is assumed that only the induction machine 103 is idle among the induction machines 101 to 104, and ωm3 becomes larger than ωm1, ωm2, and ωm4. According to Equation (6), the speed calculation errors are ωm> ωm1, ωm> ωm2, ωm> ωm4, and ωm <ωm3. As a result, the actual slips of the induction machines 101, 102, 104 increase and the actual slip of the induction machine 103 decreases with respect to the slip command ωs scheduled from the torque command τ * and the magnetic flux command φ *.

  In this state, when torque control is performed by the torque control means 4 so that the total current i is constant, the total torque matches the torque command τ *, but the individual induction machine magnetic flux magnitude is different from the magnetic flux command φ *. . The magnetic flux size of the induction machines 101, 102, 104 is smaller than the magnetic flux command φ *. The magnitude of the magnetic flux of the induction machine 103 depends on the degree of idling, but if idling is large, it becomes smaller than the flux command φ *. If idling is large, the magnetic flux size φvol is small. Using the fact that the induction machine magnetic flux magnitude φvol is smaller than the magnetic flux command φ * in the above circumstances, the detection signal K is created using the magnetic flux reference value φn and the time set value Tn. Here, the idling is taken as an example, but the same applies to the case of sliding.

  With the above configuration, the detection signal K is turned OFF after the induction machine magnetic flux magnitude φvol is smaller than the magnetic flux reference value φn and the time dependent on the time set value Tn has elapsed. As a result, it is possible to detect that some of the axles have slipped and slipped before the induction machine is out of step, and torque control of the induction machine can be stopped.

  FIG. 5 is a diagram showing an example of creating the magnetic flux reference value φn. The reference value setting unit 12 creates the magnetic flux reference value φn based on the magnetic flux command φ *. For example, the magnetic flux reference value φn is calculated as the product of the magnetic flux command φ * and the attenuation rate β. The attenuation rate β is a value from 0 to 1.

  By configuring FIG. 5, after the induction machine magnetic flux magnitude φvol becomes smaller than the magnetic flux command φ * and the time dependent on the attenuation rate β and the time set value Tn has elapsed, the detection signal K is turned OFF. If φn = β · φ *, the detection signal K is turned OFF after φvol <β · φ * and the time dependent on the time set value Tn has elapsed. As a result, it is possible to detect that some of the axles have slipped and slipped before the induction machine is out of step, and torque control of the induction machine can be stopped.

  This is not limited to the speed calculation error due to idling or sliding of some wheel shafts in vehicle control, but even if there is a difference in the shaft speeds of some induction machines that are subject to collective torque control. The invention is effective.

  FIG. 3 is a diagram showing an embodiment of the magnetic flux error calculator 8. The error rate dφ is 0 when φvol> φn, and the error rate dφ is 1 when φvol <φn. The error rate dφ is input to the integrator 9.

  Hereinafter, the integrator 9, the comparator 10, the operation logic unit 11, the torque control means 4, and the power converter 3 are the same as those in the first embodiment.

  With the above configuration, when the state of φvol <φn exists for a total time Tn, the detection signal K is turned off. As a result, it is possible to detect that some of the axles have slipped and slipped before the induction machine is out of step, and torque control of the induction machine can be stopped.

  By the way, if the error time Tφ which is the output of the integrator 9 is set to 0 in the induction machine torque control stop state, the detection signal K is turned ON, and the torque control can be started again. At this time, if the idling and sliding of a part of the axle are similarly increased, the detection of the present invention is performed again from the initial state, and if the condition is satisfied, the torque control of the induction machine is stopped.

  If the error time Tφ, which is the output of the integrator 9, is set to 0 when φvol> φn, the detection returns to the initial state when φvol> φn before the time Tn elapses. Therefore, the detection signal K is turned OFF when the state of φvol <φn continues for the time Tn.

FIG. 4 is a diagram showing an embodiment of the magnetic flux error calculator 8. The error rate dφ is calculated by the equation (8) using the calculation gain α.
dφ = (φn−φvol) / [(1−α) · φn] Equation (8)
The level of the error rate dφ with respect to the induction machine magnetic flux magnitude φvol varies depending on the value of the calculation gain α. The calculation gain α is a value less than 1. In particular, when α = 0, equation (9) is obtained, and dφ = 1 when φvol = 0.
dφ = (φn−φvol) / φn formula (9)
The error rate dφ is input to the integrator 9.

  Hereinafter, the integrator 9, the comparator 10, the operation logic unit 11, the torque control means 4, and the power converter 3 are the same as those in the first embodiment.

  Due to the configuration of the magnetic flux error calculator 8, the integrator 9, and the comparator 10, the detection signal K is turned OFF in the time that contributes to φvol. For example, when the state of φvol = α · φn continues for a time Tn, the detection signal K is turned OFF. In another example, when the state of φvol = 0 continues for time Tn / (1−α), the detection signal K is turned off. In another example, the detection signal K is not turned off if φvol ≧ φn. Thus, the time until the detection signal K is turned off varies depending on the induction machine magnetic flux magnitude φvol.

  As described in the first embodiment, if the degree of idling and sliding is large and the induction machine magnetic flux magnitude φvol is substantially less than the magnetic flux reference value φn, the error rate dφ becomes large and the detection signal K Will be turned off early. On the contrary, if the degree of idling and sliding is small and the induction machine magnetic flux magnitude φvol is slightly smaller than the magnetic flux reference value φn, the error rate dφ becomes small and the detection signal K does not readily turn off. Depending on the degree of idling and sliding, the time until the detection signal K turns off changes.

  By adopting the above configuration, it is possible to detect that the idling and sliding of some axles have increased before the induction machine is in a step-out state, and torque control of the induction machine can be stopped. The time until the torque control of the induction machine is stopped can be changed depending on the degree of idling and sliding.

  By the way, if the error time Tφ which is the output of the integrator 9 is set to 0 in the induction machine torque control stop state, the detection signal K is turned ON, and the torque control can be started again. At this time, if the idling and sliding of a part of the axle are similarly increased, the detection of the present invention is performed again from the initial state, and if the condition is satisfied, the torque control of the induction machine is stopped.

  Further, if the calculation result 0 or less of the equations (8) and (9) of the magnetic flux error calculator 8 is limited to 0 as a lower limit, the error time Tφ is not reduced even if φvol> φn. Thereby, even if φvol oscillates at φn as a boundary, the detection signal K is turned off over time. Conversely, if the calculation result 0 or less of the magnetic flux error calculator 8 is not lower limit to 0, the detection signal K is OFF when φvol oscillates at φn. It becomes difficult to become.

  If the error time Tφ, which is the output of the integrator 9, is set to 0 when φvol> φn, the detection signal K is turned OFF when the state of φvol <φn continues for a time depending on the time set value Tn.

  In the control of a plurality of induction machines such as a vehicle, it is possible to detect idling and sliding of some wheel shafts. Furthermore, the induction machine control can be stopped by the detection signal K before reaching the induction machine step-out state caused by the idling and sliding of some wheel shafts.

  Depending on how the magnetic flux error calculator 8 calculates, it is possible to change the time required for detection based on the degree of slipping and sliding of some wheel shafts. For example, if the degree of idling and sliding of some wheel shafts is small, the time until detection can be lengthened. If the degree of idling and sliding of some wheel shafts is large, the time until detection can be shortened.

  Not only the speed calculation error due to idling or sliding of some wheel shafts in vehicle control, but also when there is a difference in the shaft speed of some induction machines that are subject to collective torque control. The induction machine control can be stopped by the detection signal K before reaching the machine step-out state.

  By stopping the induction machine control, it is possible to prevent the destruction of the induction machine and the element destruction of the power converter 3 due to the overcurrent and overvoltage caused by the induction machine step-out state.

FIG. 1 is a block diagram showing an embodiment of the present invention. FIG. 2 is a block diagram showing a conventional example. FIG. 3 is a diagram showing an embodiment of the magnetic flux error calculator. FIG. 4 is a diagram showing an embodiment of the magnetic flux error calculator. FIG. 5 is a diagram showing an example of creating a magnetic flux reference value.

Explanation of symbols

101, 102, 103, 104 Induction machine 2 Current detector 3 Power converter 4 Torque control means 5 Magnetic flux calculator 6 Speed calculator 7 Magnetic flux calculator 8 Magnetic flux error calculator 9 Integrator
10 Comparator
11 Operation logic
12 Reference value setter

i Total current v Voltage command τ * Torque command φ * Magnetic flux command ωm Induction machine speed φ Induction machine magnetic flux N Operation command Φvol Induction machine magnetic flux size Φn Magnetic flux reference value α Calculation gain β Decay rate
dφ error rate
Tφ error time
Tn Time set value K Detection signal
NN control command

Claims (6)

A plurality of induction machines, a magnetic flux calculator that calculates the induction machine magnetic flux from the total current and voltage of all induction machines, and a speed calculator that calculates the induction machine speed from the induction machine magnetic flux and the total current, In the induction machine control device having torque control means for collectively controlling the torque of the induction machines based on the total current, the induction machine speed, the magnetic flux instruction, the torque instruction, and the operation instruction,
A magnetic flux amount calculator for calculating the induction machine magnetic flux magnitude from the induction machine magnetic flux, a magnetic flux error calculator for inputting the induction machine magnetic flux magnitude and the magnetic flux reference value and outputting an error rate, and integrating the error rate to obtain an error time Are newly added to the integrator that outputs a detection signal by comparing the time set value and the error time, and an operation logic unit that creates a control command from the operation command and the detection signal. An induction machine control device, wherein the control command is input to the torque control means instead of the command. In the magnetic flux error calculator,
2. The induction according to claim 1, wherein the induction machine magnetic flux magnitude φvol and the magnetic flux reference value φn are compared, and the error rate is 0 when φvol> φn, and the error rate is 1 when φvol <φn. Machine control device. In the magnetic flux error calculator,
The error rate dφ is calculated from the induction machine magnetic flux magnitude φvol and the magnetic flux reference value φn.
dφ = (φn−φvol) / φn
The induction machine control device according to claim 1, wherein the calculation is performed by: In the magnetic flux error calculator,
The error rate dφ is calculated from the induction machine magnetic flux magnitude φvol, the magnetic flux reference value φn, and the calculation gain α.
dφ = (φn−φvol) / [(1-α) · φn]
The induction machine control device according to claim 1, wherein the calculation is performed by:   2. The induction machine control device according to claim 1, wherein the magnetic flux reference value φn is created by a reference value setter that receives the magnetic flux command φ *. 2. The induction machine control device according to claim 1, wherein the magnetic flux reference value φn is a product of the magnetic flux command φ * and an attenuation factor β.

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