JP2003070291A - Motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deterioration of an apparatus, e.g. current oscillation, overheat, disconnection, short circuit and the like, of a motor. SOLUTION: The motor controller comprises a converter 1 for converting AC power into DC power; an inverter 2 for inverting DC power from the converter 1 into AC power of arbitrary frequency; and means 21-29 for controlling the converter 1 by a phase control signal, controlling the inverter 2 by a speed frequency signal based on a speed reference signal from an external reference means, and performing variable speed control of a motor 7 with AC power from the inverter 2. The controller is further provided with a stabilization compensating circuit comprising a ▵V compensation means for determining a powering state or a regenerating state from the phase control signal and, based on the voltage difference between a voltage reference 31 from a voltage reference calculating means and a motor voltage 32 from a detecting means, switching a speed frequency signal compensation value for controlling the inverter 2 on the powering side or the regenerating side thus judged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device for starting and stopping a high inertia induction motor used in, for example, a short-circuit test facility or restarting it from a free-run (natural elliptical) state, and more particularly to a motor. The present invention relates to a motor control device equipped with a stabilization compensation circuit capable of preventing deterioration of equipment such as current vibration, overheating, disconnection, and short circuit.

[0002]

2. Description of the Related Art FIG. 7 is a block circuit diagram showing an example of a basic configuration of a motor control device having a conventional stabilization compensation circuit of this type.

In FIG. 7, a converter 1 connected to an AC power source 6 converts AC power into DC power.

The inverter 2 converts direct current power into alternating current power having an arbitrary frequency and controls the induction motor 7 at a variable speed by this alternating current power.

The output voltage of the inverter 2 (= motor voltage),
The current and speed are detected by the voltage detector 3, the current detector 4, and the speed detector 5, respectively.

The control configuration is such that, with respect to the speed given by the external reference circuit 21, a speed pattern of operation modes such as forward / reverse rotation, acceleration / deceleration, remote / local, and jogging (inching) operation frequency jump is obtained. Then, the speed frequency signal is set by the speed reference circuit 23, and the V / f reference circuit 25 outputs the voltage reference signal corresponding to the load of the induction motor 7.

Then, the pulse generator 29B generates a switching pulse corresponding to the speed frequency signal, and the switching element of the inverter 2, for example, a thyristor element is activated to drive the induction conductive motor 7.

On the other hand, the converter 1 includes a voltage control circuit 26.
Performs proportional / integral calculation on the deviation between the voltage reference signal and the voltage feedback signal, and further, the current control circuit 27
The proportional / integral calculation is performed for the deviation between the current reference signal and the current feedback signal whose current has been limited by, and the phase adjuster 28 generates the phase control signal.

Then, a switching pulse corresponding to the phase control signal is generated by the pulse generator 29A, and the switching element of the converter 1, for example, a thyristor element is activated.

On the other hand, the restart command discrimination circuit 11, the operation preparation completion signal discrimination circuit 12, and the phase control signal discrimination circuit 1
3, the restart determination circuit 15 is configured based on the condition that the output signal is in the powering state, the operation preparation completion signal determination circuit 12 and the start / stop command determination circuit 14 are configured as output signal conditions. The start-stop circuit 16 is provided.

The output signal from the motor speed detection circuit 22 for detecting the speed of the induction conductive motor 7 is input to the offset circuit 24, and the signal offset by the offset circuit 24 and the speed reference circuit 23 are set. And the speed frequency signal from the restart determination circuit 15, and the output signal from the offset circuit 24 or the speed frequency signal from the speed reference circuit 23.
The "0" signal is switched by the output signal from the restart determination circuit 15 or the start / stop circuit 16.

In the case of a short-circuit test facility configured with a short-circuit generator 100 mechanically connected to the induction motor 7 driven by the motor control device, a short-circuit breaker 101, and a short-circuit EUT 102, an arbitrary frequency is set. After driving and exciting the short-circuit generator 100, the induction motor 7 is once brought into a free-run state, and the short-circuit strength of the short-circuit tested device 102 is tested. After that, the free-running induction motor 7 is restarted and the short circuit test is repeated.

In addition, the AC power source 6 also restarts in the same manner when a momentary power failure occurs due to a lightning strike or equipment failure.

Further, in the prior art, the control circuit at the time of such operation / stop and restart is the voltage reference from the voltage reference calculation means 31 which receives the output signal from the voltage control circuit 26 and the voltage detector 3. The ΔV compensating circuit 36 is provided as a stabilizing compensating circuit for compensating for the speed frequency signal for controlling the inverter 2 by multiplying the voltage deviation from the electric motor voltage from the electric motor voltage detecting means 32 by the gain adjuster 34. In this way, stabilization compensation is performed for sudden load changes in the steady state and transient responses at restart.

[0015]

However, the electric motor control device having the above-described conventional stabilization compensating circuit has the following problems.

FIG. 8 is a diagram for explaining the operation of the induction motor 7 driven by the V / f control of the inverter 2 when the load changes abruptly.

8 (a) and 8 (b) are diagrams showing the relationship (stationary coordinates) of each coordinate in the steady state and the sudden load change.

The d-q axes are stationary coordinates fixed in the induction motor 7, the de-qe axes are ideal motor stator coordinates, and de *-
The qe * axis is a coordinate that rotates in synchronization with the output of the inverter 2.

In the steady state, de-qe axis and de *-
It coincides with the qe * axis, and the induction motor 7 rotates stably.

When the load is suddenly applied to the induction motor 7 in such a state, the motor speed decreases and the slip increases, but since the output current of the inverter 2 is fixed at the output frequency, the ideal motor fixation is achieved. The de * -qe * axis rotates faster than the coordinate de-qe axis, and the coordinates are as shown in FIG. 8B.

For this reason, the locus of the current on the dq axes becomes as shown in FIG. 8C, and the magnetic flux inside the motor is reduced in the transient state.

The amount of decrease in the magnetic flux is recovered by increasing the motor current by the voltage control system, but a transient decrease in the magnetic flux and the shaft torque is unavoidable, and the speed decreases greatly due to the decrease in the shaft torque. If it cannot be recovered, the difference between the actual speed and the inverter frequency becomes larger and larger, and eventually the engine will stall.

Therefore, as a countermeasure against this, as described above,
The speed frequency signal is adjusted according to the voltage deviation between the motor voltage and the voltage reference to prevent the delay of the voltage control system and the delay of the stall control system.

Large load-> voltage decrease-> voltage control system-> current increase-> frequency decrease That is, the difference between the voltage reference and the voltage feedback is detected. If the voltage feedback is small, the frequency is decreased, and if it is large, the frequency is increased. I am trying.

As another stabilization compensation method, the speed frequency signal is adjusted in accordance with the amount of change of the phase control signal for controlling the converter 1 from the current control system, and the delay of the voltage control system and the stall control system are adjusted. I try to prevent delays.

However, the induction motor 7 is operated with a slip required to generate a torque corresponding to iron loss, friction loss and wind loss generated during operation, and is not rotated at a synchronous speed determined by the frequency and the number of poles. Can not.

Then, when a mechanical force corresponding to the loss generated at the time of operation is externally applied in the rotating direction of the induction motor 7, the induction motor 7 rotates at the synchronous speed.

In this state, the induced electromotive force of the secondary circuit is
In the case of a high inertia induction motor, when the load suddenly changes in a steady state, decelerates and stops, or restarts from a free run state, the slip "0" state or the regenerative state that acts as a generator is likely to occur. If the speed frequency signal is adjusted by the deviation between the voltage reference and the voltage reference or the amount of change in the phase control signal, on the contrary, current oscillation is caused, the overcurrent protection operation operates, and the device stops. is not.

An object of the present invention is to provide a motor control device provided with a stabilization compensation circuit capable of preventing deterioration of the device such as current vibration of the motor, overheating, disconnection and short circuit.

[0030]

To achieve the above object, a converter for converting AC power into DC power, an inverter for converting DC power from the converter into AC power having an arbitrary frequency, and an external reference. In a motor controller for controlling a converter by a phase control signal based on a speed reference signal from the means, and a control means for controlling an inverter by a speed frequency signal, and performing variable speed control of an electric motor by AC power from the inverter. In the invention according to claim 1, the power running state or the regenerative state is discriminated by the phase control signal, and the inverter is controlled based on the voltage deviation between the voltage reference from the voltage reference calculation means and the motor voltage from the detection means. The compensation value for compensating the speed frequency signal is switched between the power running state side and the regenerative state side, which are discriminated above. And a stabilizing compensation circuit consisting of V compensation means.

Therefore, in the motor control device of the invention according to claim 1, the compensation value for compensating the speed frequency signal for controlling the inverter is set to the power running state based on the voltage deviation between the voltage reference and the motor voltage. Side or the regenerative state side, that is, the converter phase is α <9, for example.
At 0 °, the phase of the fundamental wave of the output current of the inverter and the phase of the induced voltage of the motor are within ± 90 °, so the + side is compensated for the voltage deviation and the phase of the converter is α
When> 90 °, the phase of the fundamental wave of the output current of the inverter and the phase of the induced voltage of the motor are ± (90 to 180 °).
In particular, current oscillation at the start of deceleration operation is eliminated, and stable operation can be performed against load fluctuations.

In the invention according to claim 2, the speed reference signal is used to determine the acceleration state or the deceleration state, and based on the voltage deviation between the voltage reference from the voltage reference calculation means and the motor voltage from the detection means, There is provided a stabilization compensating circuit including a ΔV compensating means for switching the compensation value for compensating the speed frequency signal for controlling the inverter on the side of the acceleration state or the side of deceleration determined above.

Therefore, in the motor control device of the invention according to claim 2, the compensation value for compensating the speed frequency signal for controlling the inverter is accelerated based on the voltage deviation between the voltage reference and the motor voltage. By switching between the high-speed induction motor and the deceleration state side, stable operation can be performed regardless of the sudden change in the load in any operating state when the acceleration / deceleration time is long as in a high inertia induction motor.

Further, in the invention according to claim 3, the power running state or the regenerative state is discriminated by the phase control signal, and the speed frequency signal for controlling the inverter and the voltage reference calculating means for controlling the inverter based on the change amount of the phase control signal. There is provided a stabilization compensating circuit including frequency compensating means for switching the compensation value for compensating the voltage reference from each of the above-mentioned discriminated power running state side or regenerative state side.

Therefore, in the motor control device of the invention according to claim 3, the speed frequency signal for controlling the inverter and the compensation value for compensating the voltage reference are respectively based on the change amount of the phase control signal. The converter and inverter are controlled at the same response time by switching between the power running state side and the regenerative state side, that is, by switching the speed frequency signal and voltage reference between power running and regeneration according to the phase change amount of the converter to compensate. (Simultaneity), and stable operation can be achieved regardless of the sudden change in load under any operating condition.

On the other hand, in the invention according to claim 4, the acceleration state or the deceleration state is discriminated by the speed reference signal, and the speed frequency signal for controlling the inverter and the voltage reference are respectively determined based on the change amount of the phase control signal. There is provided a stabilization compensating circuit including frequency compensating means for switching a compensation value for compensating on the side of the acceleration state or the side of deceleration determined above.

Therefore, in the motor control device of the invention according to claim 4, the speed frequency signal for controlling the inverter and the compensation value for compensating the voltage reference are respectively based on the variation of the phase control signal. By switching between acceleration state and deceleration state side, that is, by switching the speed frequency signal and voltage reference between acceleration and deceleration according to the amount of phase change of the converter and compensating, the acceleration time / deceleration time like high inertia induction motor. When the load is long, stable operation can be performed regardless of the sudden change in the load under any operating condition.

Further, in the invention corresponding to claim 5, during the processing operation of the restart determination circuit composed of the restart command, the operation preparation completion signal, and the condition of being in the powering state from the phase control signal, A stabilization compensating circuit including restart compensating means for switching a compensation value for compensating the speed frequency signal for controlling the inverter to "0" is provided.

Therefore, in the motor control device of the invention according to claim 5, during the processing operation of the restart determination circuit,
By switching the compensation value for compensating the speed frequency signal for controlling the inverter to "0", the electric motor under restart processing is in a state where the induced electromotive force of the secondary circuit is zero for a while, Even if an electromotive force is generated, a pulsation of 6N times the inverter output frequency may be generated, and it is possible to prevent the velocity frequency signal from being compensated by the voltage deviation at this time and to fall into an unstable phenomenon.

Furthermore, in the invention corresponding to claim 6, the ΔV compensating means of the invention corresponding to claim 1 or 2 and the frequency compensating means of the invention corresponding to claim 3 or 4 are provided. The stabilization compensating circuit comprises the restart compensating means of the invention corresponding to claim 5.

Therefore, in the motor control device of the invention according to claim 6, the ΔV compensating means, the frequency compensating means, and the restart compensating means integrally perform the stabilization compensation to suppress the current oscillation. Therefore, it is possible to prevent the device from being stopped by the overcurrent protection operation due to the current vibration.

[0042]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First Embodiment) FIG. 1 is a block circuit diagram showing a configuration example of a motor control device according to the present embodiment. The same elements as those in FIG. It is omitted and only different parts will be described here.

In FIG. 1, the restart command discrimination circuit 1
1, the operation preparation completion signal determination circuit 12, the phase control signal determination circuit 13, the start / stop command determination circuit 14, the restart determination circuit 15, the start / stop circuit 16, the motor speed detection circuit 22, and the offset circuit 24 are shown in the drawing. Omitted.

In the electric motor control device according to this embodiment, the structure of the ΔV compensation circuit 36 which is a stabilizing compensation circuit forming a part of the electric motor control device in FIG. 7 is improved.

That is, the ΔV compensation circuit 3 of the present embodiment.
As shown in FIG. 1, reference numeral 6 designates a power control state or a regenerative state based on a phase control signal output from the phase adjuster 28, and a voltage reference and a voltage detector 3 calculated in a voltage control loop at a previous stage of current control. Gain adjuster 34A, a gain that is a compensation value for compensating the speed frequency signal for controlling the inverter 2 based on the voltage deviation from the motor voltage of
By 34B, switching is performed on the side of the power running state or the side of the regenerative state determined above.

A dead band circuit 33 is provided on the switching line to prevent frequent switching, and the limiter circuit 3 is provided on the output side of the gain adjusters 34A and 34B.
5A and 35B are provided.

Next, the operation of the electric motor control device according to the present embodiment configured as described above will be described.

The description of the operation of the same elements as those in FIG. 7 will be omitted, and only the operation of different parts will be described here.

In FIG. 1, the current control circuit 27 constituting the current control loop from the current detector 4 is a proportional / integral circuit.
(PI) adjuster, and operates the converter 1 based on the current reference value calculated from the current control circuit 27, and operates the phase adjuster 28 to match the current reference value.

On the other hand, in the ΔV compensation circuit 36, the power control state or the regenerative state is discriminated by the phase control signal output from the phase adjuster 28, and the voltage reference and the motor voltage calculated in the voltage control loop in the previous stage of the current control are determined. The gain, which is a compensation value for compensating the speed frequency signal for controlling the inverter 2, is switched on the power running state side or the regenerative state side determined by the gain adjusters 34A and 34B on the basis of the voltage deviation of.

That is, for example, the phase of the converter 1 is α
When <90 °, since the fundamental wave phase of the output current of the inverter 2 and the phase of the induced voltage of the induction motor 7 are within ± 90 °, the voltage deviation is compensated on the positive side, and the phase of the converter 1 is reduced. Is α> 90 °, the phase of the fundamental wave of the output current of the inverter 2 and the phase of the induced voltage of the induction motor 7 are ±.
Since it is (90 to 180 °), by compensating the negative side for the voltage deviation, current oscillation is eliminated particularly at the start of deceleration operation, and stable operation can be performed against load fluctuation.

As described above, in the motor control device according to the present embodiment, when a high inertia induction motor such as a short circuit test facility is repeatedly operated / stopped, or in a free-run state, the device under test is subjected to a short circuit test and retested. For starting up or restarting when the AC power source 6 has momentarily lost power,
Not only the suppression at the time of restart, but also the current oscillation that has occurred in other commercial synchronization or impact load can be suppressed, and the transient loss due to the current oscillation can be reduced.

Further, it is possible to prevent irregular rotation of the induction motor 7 and mechanical resonance due to the current vibration, and to prevent deterioration of the equipment such as torque vibration of the induction motor 7, overheating, and disconnection short circuit.

Further, unlike the vector control system which achieves the same effect, it is not necessary to add a current detector and a magnetic flux calculation circuit to the output side of the inverter 2, and the structure is simplified and the cost is reduced accordingly. It becomes possible.

(Second Embodiment) FIG. 2 is a block circuit diagram showing a configuration example of a motor control device according to the present embodiment. The same elements as those in FIG. It is omitted and only different parts will be described here.

In FIG. 2, the restart command discrimination circuit 1
1, the operation preparation completion signal determination circuit 12, the phase control signal determination circuit 13, the start / stop command determination circuit 14, the restart determination circuit 15, the start / stop circuit 16, the motor speed detection circuit 22, and the offset circuit 24 are shown in the drawing. Omitted.

In the electric motor control device according to the present embodiment, the structure of the ΔV compensation circuit 36 which is a stabilizing compensation circuit forming a part of the electric motor control device in FIG. 7 is improved.

That is, the ΔV compensation circuit 3 of the present embodiment.
As shown in FIG. 2, reference numeral 6 identifies the acceleration state or the deceleration state based on the speed reference signal output from the speed reference circuit 23, and the voltage reference and the voltage detector 3 calculated by the voltage control loop in the previous stage of the current control. Gain adjuster 34A, a gain that is a compensation value for compensating the speed frequency signal for controlling the inverter 2 based on the voltage deviation from the motor voltage of
34B, it is configured to switch between the determined acceleration state side and deceleration state side.

A dead band circuit 33 is provided on the switching line to prevent frequent switching, and the limiter circuit 3 is provided on the output side of the gain adjusters 34A and 34B.
5A and 35B are provided.

Next, the operation of the electric motor control device according to the present embodiment configured as described above will be described.

The description of the operation of the same elements as those in FIG. 7 is omitted, and only the operation of the different parts will be described here.

In FIG. 2, the .DELTA.V compensation circuit 36 discriminates the acceleration state or the deceleration state from the speed reference signal output from the speed reference circuit 23, and based on the voltage deviation calculated by the voltage control loop in the previous stage of the current control. Then, the gain, which is a compensation value for compensating the speed frequency signal for controlling the inverter 2, is switched on the acceleration state side or the deceleration state side determined by the gain adjusters 34A and 34B.

That is, by switching the compensation value for compensating the speed frequency signal for controlling the inverter 2 on the acceleration state side or the deceleration state side based on the voltage deviation between the voltage reference and the motor voltage, high inertia induction is achieved. When the acceleration / deceleration time is long as in an electric motor, stable operation can be performed regardless of the sudden change in the load under any operating condition.

As described above, in the motor control device according to this embodiment, the acceleration time
When the deceleration time is long, stable operation can be achieved regardless of the sudden change in load under any operating condition.

(Third Embodiment) FIG. 3 is a block circuit diagram showing an example of the configuration of a motor control device according to the present embodiment. The same elements as those in FIG. It is omitted and only different parts will be described here.

Incidentally, in FIG. 3, the restart command discrimination circuit 1
1, the operation preparation completion signal determination circuit 12, the phase control signal determination circuit 13, the start / stop command determination circuit 14, the restart determination circuit 15, the start / stop circuit 16, the motor speed detection circuit 22, and the offset circuit 24 are shown in the drawing. Omitted.

The electric motor control device according to the present embodiment omits the ΔV compensation circuit 36, which is a stabilization compensation circuit forming a part of the electric motor control device in FIG. 7, and replaces it with a new stabilization device. The frequency compensation circuit 44, which is a compensation circuit, is provided.

That is, the frequency compensating circuit 44 of the present embodiment discriminates the powering state or the regenerative state from the phase control signal output from the phase adjuster 28 as shown in FIG. 3, and changes in the phase control signal. Based on the quantity, the gain that is a compensation value for compensating the speed frequency signal for controlling the inverter 2 and the voltage reference calculated in the voltage control loop at the previous stage of the current control is set to the gain adjusters 42A and 4A.
2B and 42C are used to switch between the power running state side and the regenerative state side that have been discriminated above.

A dead band circuit 43 is provided on the switching line to prevent frequent switching, and a limiter circuit 41 is provided on the output side of the gain adjusters 42A and 42B.
B is provided, and further, a limiter circuit 41A is provided on the output side of the gain adjuster 42C.

Next, the operation of the electric motor control device according to the present embodiment configured as described above will be described.

The description of the operation of the same elements as in FIG. 7 will be omitted, and only the operation of the different parts will be described here.

In FIG. 3, the current control circuit 27 forming the current control loop from the current detector 4 is a proportional / integral circuit.
(PI) adjuster, and operates the converter 1 based on the current reference value calculated from the current control circuit 27, and operates the phase adjuster 28 to match the current reference value.

On the other hand, the frequency compensating circuit 44 discriminates the power running state or the regenerative state from the phase control signal output from the phase adjuster 28, and the speed frequency for controlling the inverter 2 based on the change amount of the phase control signal. The gain, which is the compensation value for compensating the signal and the voltage reference calculated in the voltage control loop in the previous stage of the current control, is determined by the gain adjusters 42A, 42B, and 42C on the power running state side or the regenerative state side. Switch.

That is, the converter and the inverter are controlled with the same response time (simultaneous control) by switching the speed frequency signal and the voltage reference between power running and regeneration according to the amount of phase change of the converter 1 for compensation. This enables stable operation regardless of the sudden change in load under any operating condition.

As described above, the motor control device according to the present embodiment can stably operate regardless of the sudden change in the load under any operating condition.

(Fourth Embodiment) FIG. 4 is a block circuit diagram showing an example of the configuration of a motor control device according to the present embodiment. The same elements as those in FIG. It is omitted and only different parts will be described here.

In FIG. 4, the restart command discrimination circuit 1
1, the operation preparation completion signal determination circuit 12, the phase control signal determination circuit 13, the start / stop command determination circuit 14, the restart determination circuit 15, the start / stop circuit 16, the motor speed detection circuit 22, and the offset circuit 24 are shown in the drawing. Omitted.

The electric motor control device according to the present embodiment omits the ΔV compensation circuit 36, which is a stabilization compensation circuit forming a part of the electric motor control device in FIG. 7, and replaces it with a new stabilization device. The frequency compensation circuit 44, which is a compensation circuit, is provided.

That is, as shown in FIG. 4, the frequency compensating circuit 44 of the present embodiment discriminates the acceleration state or the deceleration state from the speed reference signal output from the speed reference circuit 23, and outputs from the phase adjuster 28. The gain, which is a compensation value for compensating the speed frequency signal for controlling the inverter 2 and the voltage reference calculated in the voltage control loop in the previous stage of the current control, is adjusted based on the amount of change in the phase control signal. The devices 42A, 42B, and 42C are configured to switch between the determined acceleration state side and deceleration state side.

A dead band circuit 43 is provided on the switching line to prevent frequent switching, and a limiter circuit 41 is provided on the output side of the gain adjusters 42A and 42B.
B is provided, and further, a limiter circuit 41A is provided on the output side of the gain adjuster 42C.

Next, the operation of the electric motor control device according to the present embodiment configured as described above will be described.

The description of the operation of the same elements as those in FIG. 7 will be omitted, and only the operation of different parts will be described here.

In FIG. 4, in the frequency compensation circuit 44,
The speed reference signal output from the speed reference circuit 23 determines the acceleration state or the deceleration state, and based on the amount of change in the phase control signal output from the phase adjuster 28, the speed frequency signal for controlling the inverter 2 and the current. The gains, which are compensation values for compensating for the voltage references calculated in the voltage control loop at the pre-control stage, are set to the gain adjusters 42A and 42A.
B or 42C is used to switch between the determined acceleration state side and deceleration state side.

That is, by switching the speed frequency signal and the voltage reference between acceleration and deceleration according to the amount of phase change of the converter 1 and compensating, when the acceleration time / deceleration time is long as in a high inertia induction motor, Even if the load changes suddenly in any operating state, it can operate stably.

As described above, in the electric motor control device according to this embodiment, the acceleration time
When the deceleration time is long, stable operation can be achieved regardless of the sudden change in load under any operating condition.

(Fifth Embodiment) FIG. 5 is a block circuit diagram showing an example of the configuration of a motor control device according to the present embodiment. The same elements as those in FIG. It is omitted and only different parts will be described here.

In the electric motor control device according to the present embodiment, the structure of the ΔV compensation circuit 36 which is a stabilizing compensation circuit forming a part of the electric motor control device in FIG. 7 is improved.

That is, the ΔV compensation circuit 3 according to the present embodiment.
As shown in FIG. 5, reference numeral 6 indicates a restart command, a driving ready signal, and a phase control signal.
The restart compensating means for switching the gain of the gain adjuster 34, which is a compensation value for compensating the speed frequency signal for controlling the inverter 2, to "0" is provided.

A dead band circuit 33 is provided on the switching line so as to prevent frequent switching, and a limiter circuit 35 is provided on the output side of the gain adjuster 34.

Next, the operation of the electric motor control device according to the present embodiment configured as described above will be described.

The description of the actions of the same elements as those in FIG. 7 is omitted, and only the actions of the different parts will be described here.

In FIG. 5, a signal indicating that the restart process is being performed is output from the restart determination circuit 15, and the voltage deviation calculated in the voltage control loop in the previous stage of the current control causes the inverter 2 to operate.
The gain of the gain adjuster 34, which is a compensation value for compensating the speed frequency signal for operating the, is switched to "0" during the restart process.

That is, during the processing operation of the restart determination circuit 15, by switching the compensation value for compensating the speed frequency signal for controlling the inverter 2 to "0", the induction motor 7 undergoing the restart processing, Even if electromotive force is generated, pulsation of 6N times the inverter output frequency may be generated from the state where the induced electromotive force of the secondary circuit is zero for a while, and the speed frequency signal is changed by the voltage deviation at this time. It is possible to compensate and avoid falling into an unstable phenomenon.

As described above, in the motor control device according to the present embodiment, it is possible to prevent the unstable phenomenon by compensating the speed frequency signal by the voltage deviation.

(Sixth Embodiment) FIG. 6 is a block circuit diagram showing a configuration example of a motor control device according to the present embodiment. The same elements as those in FIGS. 1 to 5 are designated by the same reference numerals. The description is omitted, and only different parts will be described here.

Incidentally, in FIG. 6, the restart command discrimination circuit 1
1, operation ready signal discriminating circuit 12, phase control signal discriminating circuit 13, start / stop command discriminating circuit 14, start / stop circuit 1
6, the motor speed detection circuit 22 and the offset circuit 24 are not shown.

That is, as shown in FIG. 6, the electric motor control device according to the present embodiment is a ΔV compensating circuit shown in FIG. 1 or 2 as a stabilizing compensating circuit forming a part of the electric motor control device. 36, the frequency compensating circuit 44 shown in FIG. 3 or 4, and the restart compensating means shown in FIG. 5 are integrated.

Next, the operation of the electric motor control device according to the present embodiment configured as described above will be described.

The description of the operation of the same elements as those in FIGS. 1 to 5 will be omitted, and only the operation of different parts will be described here.

In FIG. 6, the ΔV compensation circuit 36 uses the phase signal output from the phase adjuster 28 or the speed reference signal output from the speed reference circuit 23 to determine the power running state / regeneration state or the acceleration state / deceleration state. The gain, which is a compensation value for compensating the speed frequency signal for controlling the inverter 2, is determined based on the voltage deviation calculated in the voltage control loop at the previous stage of the current control by determining the state.
4B, the power running state side / regeneration state side or the acceleration state side / deceleration state side, which are determined, is switched.

The frequency compensating circuit 44 uses the phase control signal output from the phase adjuster 28 or the speed reference signal output from the speed reference circuit 23 to indicate the power running state / regenerative state or the acceleration state / deceleration state. Based on the amount of change in the phase control signal, the gain, which is a compensation value for compensating the speed frequency signal for controlling the inverter 2 and the voltage reference calculated in the voltage control loop in the current control preceding stage, The gain adjusters 42A, 42B, and 42C switch between the determined power running state / regeneration state side or the acceleration state side / deceleration state side.

Further, the signal during the restart process output from the restart determination circuit 15 is used to compensate the speed frequency signal for operating the inverter 2 by the voltage deviation calculated in the voltage control loop in the previous stage of the current control. The gains of the gain adjusters 34A and 34B, which are compensation values, are switched to "0" during the restart process.

As described above, in the motor controller according to this embodiment, the ΔV compensation circuit 36 and the frequency compensation circuit 4 are used.
4. By performing the stabilization compensation integrally by the restart compensation means, it is possible to suppress the current oscillation and prevent the apparatus from being stopped by the overcurrent protection operation due to the current oscillation.

(Other Embodiments) The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention at the stage of implementation. Is. In addition, the respective embodiments may be implemented in combination as appropriate as possible, and in that case, combined operation effects can be obtained. Further, the above-described embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent features. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiment, the problem (at least one) described in the section of the problem to be solved by the invention can be solved, and When the effect (at least one) described in the section can be obtained, a structure in which this constituent element is deleted can be extracted as an invention.

[0106]

As described above, according to the electric motor control device of the present invention, when a high inertia induction motor such as a short circuit test facility is repeatedly operated / stopped, or a short circuit test of a device under test is performed in a free run state. Not only when the AC power source instantaneously loses power, but also when restarting, the current oscillation that occurs in other commercial synchronizations and impact loads is suppressed. It is possible to reduce the transient loss due to current oscillation.

Further, it is possible to prevent irregular rotation of the electric motor and mechanical resonance due to the above current vibration, and to prevent deterioration of the device such as torque vibration of the electric motor, overheating, and disconnection short circuit.

Further, unlike the vector control system for achieving the same effect, it is not necessary to add a current detector and a magnetic flux operation circuit to the output side of the inverter, and the structure can be simplified and the cost can be reduced accordingly. Is possible.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing a first embodiment of a motor control device according to the present invention.

FIG. 2 is a block circuit diagram showing a second embodiment of an electric motor control device according to the present invention.

FIG. 3 is a block circuit diagram showing a third embodiment of an electric motor control device according to the present invention.

FIG. 4 is a block circuit diagram showing a fourth embodiment of an electric motor control device according to the present invention.

FIG. 5 is a block circuit diagram showing a fifth embodiment of a motor control device according to the present invention.

FIG. 6 is a block circuit diagram showing a sixth embodiment of an electric motor control device according to the present invention.

FIG. 7 is a block circuit diagram showing a basic configuration example of a conventional electric motor control device.

FIG. 8 is a diagram showing stationary coordinates when a load of an inverter-driven electric motor suddenly changes.

[Explanation of symbols]

1 ... Converter 2 ... Inverter 3 ... Voltage detector 4 ... Current detector 5 ... Speed detector 6 ... AC power source 7 ... Induction motor 8 ... DC reactor l1 ... Restart command discrimination circuit 12 ... Operation ready judgment circuit 13 ... Phase signal discrimination circuit 14 ... Start / stop command discrimination circuit 15 ... Restart determination circuit 16 ... Start / stop circuit 21 ... External reference circuit 22 ... Motor speed detection circuit 23 ... Speed reference circuit 24 ... Offset circuit 25 ... V / f reference circuit 26 ... Voltage control circuit 27 ... Current limiting circuit 28 ... Current control circuit 29 ... Pulse generator 31 ... Voltage reference calculation means 32 ... Motor voltage detection means 33 ... Dead band circuit 34 ... Gain adjuster 35 ... Limiter circuit 36 ... ΔV compensation circuit 41 ... Limiter circuit 42 ... Gain adjuster 43 ... Dead band circuit 44 ... Frequency compensation circuit 100 ... Short-circuit generator 101 ... Short circuit breaker 102 ... Device under test.

Claims (6)

[Claims] 1. A phase control based on a converter for converting AC power into DC power, an inverter for converting DC power from the converter into AC power having an arbitrary frequency, and a speed reference signal from an external reference means. While controlling the converter by a signal, comprising a control means for controlling the inverter by a speed frequency signal, in a motor control device for variable speed control of the electric motor by the AC power from the inverter, the power running state by the phase control signal or The regenerative state is determined, and the compensation value for compensating the speed frequency signal for controlling the inverter is determined based on the voltage deviation between the voltage reference from the voltage reference calculation means and the motor voltage from the detection means. Switch between the power running state and the regenerative state side △
An electric motor control device comprising a stabilizing compensating circuit comprising V compensating means. 2. A phase control based on a converter for converting AC power into DC power, an inverter for converting DC power from the converter into AC power having an arbitrary frequency, and a speed reference signal from an external reference means. While controlling the converter by a signal, comprising a control means for controlling the inverter by a speed frequency signal, in a motor control device for variable speed control of the electric motor by the AC power from the inverter, in the acceleration state by the speed reference signal or The deceleration state is determined, and the compensation value for compensating the speed frequency signal for controlling the inverter is determined based on the voltage deviation between the voltage reference from the voltage reference calculation means and the motor voltage from the detection means. Switch between acceleration and deceleration side △
An electric motor control device comprising a stabilizing compensating circuit comprising V compensating means. 3. A converter for converting AC power into DC power, an inverter for converting DC power from the converter into AC power having an arbitrary frequency, and a phase control based on a speed reference signal from an external reference means. While controlling the converter by a signal, comprising a control means for controlling the inverter by a speed frequency signal, in a motor control device for variable speed control of the electric motor by the AC power from the inverter, the power running state by the phase control signal or A regenerative state is determined, and based on the amount of change in the phase control signal, a speed frequency signal for controlling the inverter, and a compensation value for compensating the voltage reference from the voltage reference calculation means, respectively,
An electric motor control device comprising a stabilization compensating circuit including frequency compensating means for switching between the determined power running state side or regenerative state side. 4. A phase control based on a converter for converting AC power into DC power, an inverter for converting DC power from the converter into AC power having an arbitrary frequency, and a speed reference signal from an external reference means. While controlling the converter by a signal, comprising a control means for controlling the inverter by a speed frequency signal, in a motor control device for variable speed control of the electric motor by the AC power from the inverter, in the acceleration state by the speed reference signal or A deceleration state is determined, and based on the amount of change in the phase control signal, a speed frequency signal for controlling the inverter, and a compensation value for compensating the voltage reference from the voltage reference calculation means, respectively,
An electric motor control device comprising a stabilization compensating circuit including frequency compensating means for switching between the determined acceleration state side and deceleration state side. 5. A phase control based on a converter for converting AC power into DC power, an inverter for converting DC power from the converter into AC power having an arbitrary frequency, and a speed reference signal from an external reference means. A controller for controlling the converter by a signal and a controller for controlling the inverter by a speed frequency signal, and in a motor controller for controlling a variable speed of an electric motor by AC power from the inverter, a restart command, an operation preparation completion signal , And during the processing operation of the restart determination circuit composed of the condition that the power control state is changed from the phase control signal, the compensation value for compensating the speed frequency signal for controlling the inverter is switched to “0”. An electric motor control device comprising a stabilization compensating circuit including a starting compensating means. 6. A phase control based on a converter for converting AC power into DC power, an inverter for converting DC power from the converter into AC power having an arbitrary frequency, and a speed reference signal from an external reference means. 3. A motor control device, comprising: a control unit that controls the converter by a signal and a control unit that controls the inverter by a speed frequency signal; and a variable speed control of an electric motor by AC power from the inverter. And a frequency compensating means according to claim 3 or 4, and a restart compensating means according to claim 5, comprising a stabilization compensating circuit. A characteristic motor control device.