JPH07143794A - Fail-safe circuit for multi-rotor motor system - Google Patents

Abstract

PURPOSE:To employ a simple single stage fail-safe circuit for the control of a plurality of motors. CONSTITUTION:Target values of torque TA*, PB* to be born are determined at the operating stages of induction motors 23A, 23B for a torque input command T* and then flux current commands ithetaAD, ithetaBD and torque current commands ideltaAD, ideltaBD are operated based on the TA*, TB*. These commands are subjected to D/A conversion at a two-phase/three-phase converting section 33 and then converted through a coordinate converter 38 into a three-phase AC signal for driving each motor through an inverter 22. An adder 14 adds the torque currents ideltaA, ideltaB for each motor. When the difference between the sum and the torque input command T* is larger than a decision criterion, a fail-safe signal is delivered to shut down the contactor 24 for each inverter 22. This circuit can detect a case where a value difference from a torque input command is operated due to the abnormality of a microcomputer constituting an operating stage positively while simplifying the circuitry.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fail-safe circuit for ensuring the safety and reliability of a multi-rotor motor system, and more particularly to a fail-safe circuit for a computer in the system.

[0002]

2. Description of the Related Art As a fail-safe circuit of a conventional computer, for example, as shown in FIG.
STEM ARCHITECTURES FOR SA
FETY CRITICAL AUTOMOTIVE
APPLICATIONS. 1990 IEEE CON
There is a circuit shown in "F".

In the circuit of FIG. 5, a control computer 40 performs arithmetic processing on an input and outputs a control output. The control computer 41 attached to this is the same as the previous control computer 4
It has the same configuration and software as 0, and performs the same control output for the same input. The failure determiner 42 compares and monitors the outputs of both the control computers 40 and 41. If there is a difference in the outputs, the failure determiner 42 determines that a failure has occurred in the control computer 40 or the control computer 41, and determines that the failure has occurred. -The fail-safe operation is performed and the fail-safe operation of the control system is performed by stopping the operation of the actuator. With this configuration, it is possible to reliably detect a failure of the computer that is difficult to detect and may impair safety, and it is possible to enhance the reliability of the control system together with the failure detection of the parts other than the computer. .

The fail-safe circuit shown in FIG. 6 does not detect all failures as the circuit shown in FIG. 5, but focuses on a portion which poses a safety problem. The control computer 40 ', as with the control computer 40 of FIG. 5, performs arithmetic processing on an input and outputs a control output. Failure determiner 44
Monitors the input / output signals of the control computer 40 'and the intermediate variables to detect faults in the operation of the control system that pose a safety problem. If a failure is detected, the same as above
The fail-safe operation is performed by shutting down the system with the fail-safe output, and the failure of the computer is surely detected to enhance the reliability of the control system.

[0005]

However, in the conventional fail-safe circuit of such a computer, two control computers 40 and 41 having the same structure are provided for detecting a failure. If there is a difference between the input signal and the output signal, the failure determination circuit 44 is configured to match, and one control stage requires one fail-safe circuit. , Multi-
When these fail-safe circuits are applied to a tamoter system, each motor control stage must have a fail-safe circuit, and the failure determiner is complicated. There was a problem that it would be a different configuration.

The present invention has been made in view of the above problems, and in a multi-rotor motor system for outputting torque from a plurality of motors sharing an output shaft, a plurality of motor control stages are provided. In contrast, a single-stage fail-safe
A multi-loft circuit that can reliably detect faults and perform failsafe operations with high safety and reliability.
It is an object of the present invention to provide a fail-safe circuit for a motor system.

[0007]

In order to achieve the above object, the present invention provides a multi-rotor motor system which generates an output torque according to a torque command from a plurality of induction motors sharing an output shaft. A plurality of calculation stages which are provided for each induction motor, calculate a shared torque target value based on a torque input command, and calculate a torque current command and a magnetic flux current command corresponding to the shared torque target value; Each induction motor is driven and each induction motor is driven by a control stage including a two-phase / three-phase conversion unit that converts a current command and a magnetic flux current command into a three-phase AC signal and an inverter to which the three-phase AC signal is input. -An adder that outputs the torque inverse calculation value by summing the torque component current commands extracted from the control stage corresponding to the controller, and a fader based on the error between the torque inverse calculation value and the torque input command. It was assumed to have an abnormality determination circuit that outputs a safe signal.

[0008]

In each operation stage, the shared torque target value of the corresponding induction motor is calculated based on the torque input command, and the torque current command and the magnetic flux current command corresponding to the target value are calculated. In the 2-phase / 3-phase converter, the torque current command and the magnetic flux current command are converted into a 3-phase AC signal and input to the inverter to drive the corresponding induction motor. A torque current command corresponding to each torque current command is extracted corresponding to each induction motor, and the sum thereof is output as a torque inverse calculation value. Then, in the abnormality determination circuit, a fail-safe signal is output when the error between the inverse torque calculation value and the torque input command input to each operation stage is larger than a predetermined reference value. As the torque component current command, a torque current command obtained by inversely converting the above three-phase AC signal into a three-phase two-phase signal, or a torque current command calculated at a calculation stage before being converted into a three-phase AC signal Is used.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a first embodiment applied to the control of two induction motors sharing an output shaft as a multi-rotor motor system. The control stage for each induction motor includes an operation stage 2, a two-phase / three-phase conversion unit 3, and a drive unit 4, and the operation stage 2 and the two-phase / three-phase conversion unit 3 are integrally configured by a microcomputer. ing.

Driving unit 4A for driving the induction motor 23A
Means that the current control type inverter 22 outputs the three-phase AC signals iuAD and ivAD output from the two-phase / three-phase conversion section 3A to D /
The iuA and ivA signals converted into analog by the A converters 18 and 19 and the iwA signal generated from iuA and ivA by the adder 21 are driven, and the inverter 22 is connected to the power source through the contactor 24.

Similarly, also on the induction motor 23B side, the inverter of the same configuration in the drive unit 4B uses the D / A converter to convert the three-phase AC signals iuBD and ivBD from the two-phase / three-phase conversion unit 3B. Converted iuB and ivB signals and iwB by adder
It is driven by a signal and is connected to a power supply via a contactor.

A torque input command T * is input to the operation stage 2A as A
The digital torque input command TD * digitized by the / D converter 1 is input. Inside the operation stage 2A,
The torque division calculator 5 uses the digital torque input command TD *
Based on the above, the shared torque target value TA * shared by the induction motor 23A is calculated, and this is input to the torque current calculation unit 7. The sharing torque target value TA * is also input to the magnetic flux command calculation unit 6, where the magnetic flux command is calculated.

[Outer 1] Is output. The magnetic flux command is input to the exciting current calculation unit 8,
The exciting current calculated here is output as the magnetic flux current command iγAD.

Magnetic flux command

[Outside 2] Is further input to the torque current calculator 7. In the torque current calculation unit 7, the shared torque target value TA * and the magnetic flux command

[Outside 3] Based on, the torque current command iδAD is output. The magnetic flux current command and the torque current command are calculated on the γ-δ coordinates, which is a two-phase rotation coordinate system, and the two-phase / three-phase conversion unit 3 is used.
It is output to the γ-δ / 3-phase AC coordinate conversion unit 11 of A.

On the other hand, the pulse output from the encoder 22 attached to the induction motor 23 with the rotation of the induction motor is output to the motor rotation angular frequency calculation unit 9 in the arithmetic stage 2A. It is input and the motor rotation angular frequency ωre is calculated. In the operation stage 2A, the torque current command and the magnetic flux command are further input to the slip angular frequency calculation unit 10 to calculate the slip angular frequency ωse according to the vector control law, and the sum of this and ωre becomes the output frequency ω.

In the 2-phase / 3-phase converter 3A, the output frequency ω is processed by the integrator 12 and the output voltage phase θ is output. The γ-δ / 3-phase AC coordinate conversion unit 11 calculates the 3 based on the magnetic flux current command, the torque current command, and the output voltage phase θ.
Outputs phase alternating current signals iuAD and ivAD. Further, in the two-phase / three-phase conversion section 3A, the three-phase / two-phase conversion circuit 13 converts and outputs the torque current command recalculation value iδAS from the three-phase AC signal and the output voltage phase θ by inverse conversion. This is converted by the D / A converter 20 into an analog signal iδA to create a comparison value of the fail-safe circuit.

Similarly, in the control of the induction motor 23B, in the operation stage 2B, the divided torque target value TB * shared by the induction motor 23B is calculated by the torque division calculation unit 5 from the digital torque input command TD *, Based on this, the γ-δ / 3-phase AC coordinate conversion section 11 of the 2-phase / 3-phase conversion section 3B outputs the 3-phase AC signals iuBD and ivBD. Further, in the two-phase / three-phase conversion section 3B, the three-phase / two-phase conversion circuit 13 converts and outputs the torque current command recalculation value iδBS by inverse conversion. The torque current command recalculated value iδBS is converted into a comparison analog signal iδB of the fail-safe circuit by the D / A converter 20 outside the microcomputer.

A comparison torque current command recalculated value analog signal iδA, iδB output from each D / A converter 20.
Are input to and added to the adder 14 of the fail-safe circuit. The torque inverse calculation value T of the addition output and the original torque input command T * are input to the differential amplifier 15 to obtain the error e, and the absolute value output is obtained through the absolute value amplifier 16. This absolute value output is compared with a predetermined judgment value Tδ0 by the comparator 17, and if the error e is larger than Tδ0, "H" is output as a fail-safe signal.

Next, the operation of the above configuration will be described. The torque input command T * is converted into a digital torque input command TD * by the A / D converter 1, and the induction stage 23A of each induction motor 23A is calculated by the torque dividing calculation unit 5 of the calculation stages 2A and 2B for each motor. , 23B, the shared torque target values TA * and TB * to be shared and output are calculated. Here, T * = TA *
It becomes + TB *. Each of the operation stages 2A and 2B performs a so-called vector control operation for separately controlling the magnetic flux current command and the torque current command based on the shared torque target values TA * and TB *.

That is, here, the slip angular frequency ωse of the motor is controlled as follows.

[Equation 1] Where ω: command frequency ωre: motor rotation frequency M: mutual inductance R: rotor resistance L: inductance iδ: torque current

[Outside 4] Is. The slip angular frequency calculation unit 10 calculates the slip angular frequency ωse, and the command frequency is obtained by ω = ωse + ωre. In the operation stage 2A, the command frequency ωA thus obtained is integrated by the integrator 12 to obtain the output voltage phase θA.

When the vector control is performed in the torque current calculation unit 7, the number of pole pairs is p and the torque is

[Equation 2] Is expressed as

[Equation 3] Is calculated as the torque current command. Further, in the exciting current calculation unit 8,

[Equation 4] Is calculated as the magnetic flux current command.

From the torque current command iδAD, the magnetic flux current command iγAD, and the output voltage phase θA obtained at the operation stage 2A, the two-phase / three-phase converter 3B uses the γ-δ / 3-phase AC coordinate converter 11 to generate the three-phase AC. The signals iuAD and ivAD are obtained by coordinate conversion by the following calculation.

[Equation 5]

As described above, the three-phase AC signal obtained by the vector control calculation is converted into analog signals iuA and ivA by the D / A converters 18 and 19 in the driving unit 4A, and iwA = -iuA by the adder 21. -IvA is created, and iuA, ivA, and iwA are input to the inverter 22. As a result, the current control inverter 22 drives the induction motor 23A to output the torque TA equal to the sharing torque target value TA *. This output torque is

[Equation 6] Becomes However, pA is the number of poles and MA is the mutual inductance. Therefore, TA becomes proportional to the torque current command iδA.

The same vector control calculation is performed in the control stage of the other induction motor 23B, and the torque generated by the induction motor 23B becomes equal to the shared torque target value TB *. Therefore, its output torque is

[Equation 7] And becomes proportional to the torque current command iδB.
However, pB is the number of poles and MB is the mutual inductance.
Therefore, the input torque input command T * is divided into the respective divided torque target values TA * and TB * of the respective motors, and these drive the induction motors 23A and 23B.

Next, the operation of the fail-safe circuit will be described. The 3-phase AC signals obtained by the γ-δ / 3-phase AC coordinate conversion unit 11 are inversely converted into 2-phase signals by the 3-phase 2-phase conversion circuit 13 again in the same 2-phase 3-phase conversion units 3A and 3B. , Torque current command recalculated values iδAS and iδBS are output. Each D / A converter 20 converts this into analog signals iδA and iδB.

The analog signals iδA and iδB of the comparison torque current command recalculated values which are detected and output from the control stage of each motor are added to the adder 14 of the fail-safe circuit.
Input to and take the sum of iδA and iδB,

[Outside 5] Is output.

[Outside 6] The original torque input command T * is compared with the original torque input command T * by the differential amplifier 15 to output the error e, and the error e is set as an absolute value by the absolute value amplifier 16, and the comparator 17 sets a predetermined judgment reference value Tδ.
Compare with 0. If the error value | e | is the criterion value Tδ
If it is greater than 0, the comparator 17 performs a fail-safe operation of shutting off the contactors 24 of the drive units 4A and 4B by outputting "H", and also outputs a separate alarm if necessary.

As described above, in this embodiment, only one stage of fail-safe is used for the control stage of two motors.
With a simple configuration of a f-circuit, a reliable fail-safe operation is possible, and the γ-δ / 3-phase AC coordinate conversion unit 11 and the 3-phase 2
Since the two-phase / three-phase conversion section including the phase conversion circuit 13 is also configured by the microcomputer, there is an advantage that other hardware is simplified. Further, the embodiment is an induction motor.
Although the description has been made on the case where the number of the motors is two, the configuration does not change even for a larger number of motor sets as far as the fail-safe circuit is concerned, only the number of inputs to the adder increases.

Next, FIGS. 3 and 4 show a second embodiment in which two-phase / three-phase coordinate conversion is performed by an external hardware. Operation stage 2A composed of a microcomputer
From the torque current calculation unit 7, the torque current command iδAD
The magnetic flux current calculation unit 8 outputs the magnetic flux current command iγAD to the outside. A command frequency ωA obtained by adding the rotation frequency ωre of the motor to the slip angular frequency ωse calculated by the slip angular frequency calculator 10 is also output from the calculation stage 2A.

Then, the torque current command iδAD and the magnetic flux current command iγAD are converted into a torque current iδA and a magnetic flux current iγA by the D / A converters 35 and 36 of the two-phase / three-phase converter 33A which is external to the microcomputer, and the commands Frequency ω
The output voltage phase θA is created by counting A with an external counter 37. Torque current iδA and magnetic flux current iγA
And the output voltage phase θA are calculated by the coordinate converter 3 outside the operation stage 2A.
It is input to 8 and converted into a three-phase AC signal. Then, this three-phase AC signal is sent to the inverter 22 which constitutes the drive unit 34A to drive the induction motor 23A.

On the other hand, similarly, the torque current command iδBD, the magnetic flux current command iγBD, and the command frequency ωB are output from the operation stage 2B to the outside, and the torque current iδB, the magnetic flux current iγB, and the command frequency ωB are used to output a three-phase coordinate converter. The AC signal is converted and output to the inverter of the drive unit 34B, and the induction motor 2
Drive 3B. The other structure is the same as that of the previous embodiment.

The torque current values i δA and i δB are input to the adder 14 of the fail-safe circuit, and the sum output and the torque input command T * are input to the differential amplifier 15 to input the error e.
Ask for. The comparator 17 compares the output error value | e | of the absolute value amplifier 16 with a predetermined determination reference value Tδ0,
If | e | is large, fail-safe output is performed.

As described above, in the present embodiment, the coordinate converter 38 and the like are configured as external hardware for the operation stages 2A and 2B composed of microcomputers, so that the operation load on the microcomputers is reduced. There is an advantage that it is possible to construct an effective fail-safe system even in a microcomputer having a slow operation speed.

[0032]

As described above, according to the present invention, in controlling the multi-rotor motor system, the torque component current command output from the control stage of each motor is transmitted to the hardware outside the arithmetic stage. It is assumed that the addition is performed by the adder of the fail-safe circuit constituted by the above, the sum is calculated, the error from the torque input command is detected, and the fail-safe is performed based on the size of the error. Even if the calculation stage is composed of a microcomputer, even if an abnormality occurs with respect to the torque that is a safety problem of the motor control system and a value different from the torque input command is calculated and output, this should be ensured. There is an effect that it is possible to detect and fail-safe, and the structure itself of the fail-safe circuit can be simplified.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a block diagram showing a first embodiment of the present invention.

FIG. 3 is a block diagram showing a second embodiment.

FIG. 4 is a block diagram showing a second embodiment.

FIG. 5 is a block diagram showing a conventional example.

FIG. 6 is a block diagram showing another conventional example.

[Explanation of symbols]

 1 A / D converter 2 Calculation stage 3 2 phase 3 phase conversion unit 4 Drive unit 5 Torque division calculation unit 6 Magnetic flux command calculation unit 7 Torque current calculation unit 8 Excitation current calculation unit 9 Motor rotation angular frequency calculation unit 10 Slip Angular frequency calculation unit 11 γ-δ / 3-phase AC coordinate conversion unit 12 Integrator 13 Three-phase two-phase conversion circuit 14 Adder 15 Differential amplifier 16 Absolute value amplifier 17 Comparators 18, 19, 20 D / A converter 21 Adder 22 Inverter 23 Induction Motor 24 Contactor 25 Encoder 33 2 Phase 3 Phase Converter 34 Drive 35, 36 D / A Converter 37 Counter 38 Coordinate Converter 40, 40 ', 41 Control Computer 42,44 Failure judgment device

Claims (5)

[Claims] 1. A multi-rotor motor system that generates output torque according to a torque command from a plurality of induction motors sharing an output shaft, is provided for each induction motor, and is based on a torque input command. A plurality of calculation stages for calculating a shared torque target value and calculating a torque current command and a magnetic flux current command corresponding to the shared torque target value, and converting the torque current command and the magnetic flux current command into a three-phase AC signal 2 Each induction motor is driven by a control stage including a three-phase conversion unit and an inverter to which the three-phase AC signal is input, and the torque extracted from the control stage corresponding to each induction motor. An adder that outputs the sum of the divided current commands and outputs a torque inverse calculated value; and an abnormality determination circuit that outputs a fail-safe signal based on the error between the torque inverse calculated value and the torque input command A fail-safe circuit for a multi-rotor motor system, which has: 2. In each of the control stages, the two-phase / three-phase conversion section is configured by a microcomputer together with an operation stage, and the three-phase AC signal is converted into three-phase / two-phase to output the torque-current command. 2. A fail-safe circuit for a multi-rotor motor system according to claim 1, further comprising a phase-to-two-phase conversion circuit. 3. In each of the control stages, the operation stage has a torque division operation unit for calculating a corresponding torque target value of the induction motor from the torque input command according to a predetermined torque allocation, and a rotation detection. A calculation unit that calculates the rotational angular frequency of the induction motor based on the input signal from the means, a torque current calculation unit that calculates a torque current command from the shared torque target value, and a magnetic flux that calculates a magnetic flux command from the shared torque target value. The rotation angular frequency and the slip are provided by including a command calculation unit, an excitation current calculation unit that calculates a magnetic flux current command from the magnetic flux command, and a slip angular frequency calculation unit that calculates a slip angular frequency from the torque current command and the magnetic flux command. A command frequency is calculated from a sum of angular frequencies, and the two-phase to three-phase conversion unit integrates the command frequency and outputs an output voltage phase, and 3. The multi-rotor motor system according to claim 2, further comprising: a .gamma .-. Delta./3-phase AC coordinate conversion unit for obtaining a 3-phase AC signal based on the torque current command, the magnetic flux current command, and the output voltage phase. Fail-safe circuit. 4. The control stage in each of the control stages is configured by a microcomputer, and the torque current command is output based on the torque current command calculated by the calculation stage. A fail-safe circuit of the multi-rotor motor system according to item 1. 5. In each of the control stages, the operation stage includes a torque division operation unit for calculating a corresponding torque target value of the induction motor from the torque input command according to a predetermined torque allocation, and a rotation detection. A calculation unit that calculates the rotational angular frequency of the induction motor based on the input signal from the means, a torque current calculation unit that calculates a torque current command from the shared torque target value, and a magnetic flux that calculates a magnetic flux command from the shared torque target value. The rotation angular frequency and the slip are provided by including a command calculation unit, an excitation current calculation unit that calculates a magnetic flux current command from the magnetic flux command, and a slip angular frequency calculation unit that calculates a slip angular frequency from the torque current command and the magnetic flux command. A command frequency is calculated from the sum of angular frequencies, and the two-phase / three-phase conversion unit counts the command frequency to obtain an output voltage phase, A D / A converter for D / A conversion serial torque current command and flux current command, respectively,
A coordinate converter that obtains a three-phase AC signal based on the output voltage phase and the D / A converted torque current command and the magnetic flux current command. The D / A converted torque current command is used as the torque component current command. 5. The fail-safe of a multi-rotor motor system according to claim 4, wherein the fail-safe is output.
Circuit.