JP3123220B2 - Pickup method of PM motor in inverter system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter system which is free running due to an instantaneous power failure or failure.
Picked up operation or picking up of the PM motor Tsu about picking up top-up of how to stop.

[0002]

2. Description of the Related Art Conventionally, an inverter system using a PM motor has the following functions.

(1) Pickup Function of Inverter The PM motor that has become free-run due to an instantaneous power failure or the like is picked up and operated. In this case, the inverter detects the phase of the induced voltage from the PM motor according to the flow shown in FIG. 6, outputs a voltage having a frequency corresponding to the phase at a timing synchronized with the phase, and picks up the motor to perform the operation.

(2) Inverter overcurrent cutoff function When a load is temporarily applied to the PM motor while the inverter is operating, the inverter operates at an overcurrent level (about 15 times the rated current).
0%), the output of the inverter main circuit element is base-blocked, the output is temporarily stopped, and the operation is automatically restarted after 100 msec. If the PM motor has not reached the overcurrent level, the operation is continued.

[0005] However, the number of retries for re-operation after the detection of the overcurrent cutoff level is determined. If the overcurrent level is exceeded after the number of retries, the inverter is stopped and re-operation is not performed. I have.

In the inverter without the overcurrent cutoff function, the inverter stops at the overcurrent protection level (about 300% of the rated value) and does not restart.

[0007]

The above two functions exist independently, and the overcurrent cutoff function in the pick-up operation is not applied. For this reason, if there is a sudden change in the rotation speed of the PM motor during detection of the induced voltage of the pick-up operation, the inverter outputs a voltage in a phase different from the actual rotation of the PM motor, and overcurrent flows and overcurrent flows. Stop at protection level.

Originally, the pick-up operation function is to pick up the motor and continue the operation even when an instantaneous power failure or the like occurs. If it stops due to overcurrent at the time of picking up, the effect of the picking up function will be diminished. The same applies to pick-up and stop.

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem, and an object of the present invention is to use an overcurrent cut-off retry function at the time of picking up operation and to stop an overcurrent at the time of picking up. and to provide a top down how picking the PM motor in can reduce inverter system.

[0010]

SUMMARY and effects of the Invention The above up how picking the PM motor in the inverter system in the present invention in order to achieve the above object, when the PM motor driven by the inverter becomes coasting drive Inverter or pick-up stop dedicated inverter detects the induced voltage of the PM motor, judges the phase of the induced voltage, and outputs when the phase substantially matches the phase of the inverter voltage.
Picked on Gedo operation of the motor, or picked up in which the picking up execution of the operation for stopping, the pick operation <br/> performed after the PM motor current is determined whether overcurrent level, overcurrent level In the above case, the pick-up operation is stopped, an overcurrent cut-off retry function for judging the number of retries after a predetermined time has elapsed and retrying from the beginning is provided , and the current to the PM motor at the time of executing the pick-up operation is an overcurrent level. a predetermined number of retries until below, is performed reliably on up picking the PM motor.

[0011]

In EXAMPLE 1 FIG. 1, 1 is an inverter, PM motor 2 is driven by the inverter 1, MC inverter 1 and the PM motor
2 shows an electromagnetic contactor connected between them . The pick-up operation of the PM motor 2 that has become free-run due to an instantaneous power failure or the like uses an arithmetic unit (not shown) of the inverter 1 to take in the induced voltage of the PM motor and perform the processing shown in FIG. In FIG. 2, A indicates an overcurrent cut-off retry function that is conventionally added to the flow shown in FIG.

[0012] PM when the inverter power supply is momentarily interrupted
The motor pick-up processing operation will be described with reference to FIGS.

[0013] If the inverter power supply is momentary power failure, power failure t ₁ at the same time the inverter 1 stops output, it starts the process of FIG. 2 at time t ₂ when power is restored. The PM motor 2 is temporarily rotating due to inertia. Inverter 1 is
First, the induced voltage of the PM motor 2 is detected from the taken-in voltage, the phase thereof is determined, and when it is determined that the phases are substantially matched, the PM motor pick-up operation is executed (S1 to S1).
S3).

At this time, it is determined whether or not the output current of the inverter flowing into the PM motor 2 has reached the overcurrent level (OCR level = approximately 150% of the rated current ) (S4) .
If the OCR level has not been reached, it is determined that the pickup has been successful, and the operation is continued as it is (S5 ).

The execution of the pick-up operation (S3) causes the current to exceed the OCR level, and the result of determination in step S4 becomes Y.
When it is picked up fails regarded pick up stop operation (S6), to retry from the beginning on the action execution frequency picked at 100msec delay (S7) a (number of tries) is determined (S8) (S1 to S8).

[0016] When the current at the time of re-try to pick up operation execution has exceeded the OCR level is failed and regarded again, to try from the beginning. Judging how many times the number of tries is, if the number reaches the predetermined N times, the inverter is completely stopped and a failure output is issued assuming that it is impossible to pick up (S8 to S1).
0).

As described above, if an overcurrent of about 150% flows during execution of the pick-up operation, retry is performed in the same manner as pick-up failure, so that the electromagnetic contactor MC has an overcurrent protection level (about 300% of the rated value). Retry can be performed up to a predetermined N times without interruption.

Thus, the pickup operation can be continued during the retry up to N times. Further, since the retry is repeated at an overcurrent of about 150% of the rated value, it is possible to prevent a secondary disaster such as a breakdown of a main circuit transistor element of the inverter due to the overcurrent protection level.

Embodiment 2 In FIG. 4, 1 is a drive inverter, 2 is a PM motor driven by the inverter 1, 3 is a pick-up and stop inverter for stopping the PM motor that has become free run, and a and b are electromagnetic contacts. Indicates the contacts of the container.

As shown in FIG. 4, when a single inverter 1 is driving a plurality of PM motors, the inverter 3 dedicated to picking up and stopping is controlled by an electromagnetic contactor a1.
PM motor 2 ₁ became a free run disconnected from the 3,
Especially in the case of a roll load, since a significant amount of time to stop consuming defective products increases, and is for stopping the motor 2 ₁ from which it free-run electromagnetic contactor a2 early (prior art).

In the second embodiment, the pick-up and stop process is performed in accordance with the flow of FIG. 5 by incorporating the induced voltage of the PM motor that has become free run into the pick-up and stop dedicated inverter of FIG. Differences in the processing of FIG. 5 of treatment as in Example 2 in FIG. 2 of Example 1, the judgment result is picked operation succeeds step S4
When N becomes N, the operation is continuously performed in the next step S5 ( FIG. 2 ), or the frequency is rapidly decreased to stop the engine rapidly ( FIG. 2 ) .
5 ) The only difference is.

Therefore, according to the second embodiment, if the PM motor 2 separated from the inverter 1 is picked up and failed to be picked up by the stop-dedicated inverter 3 as in the first embodiment, the PM motor 2 can be picked up quickly by retry. can, can be stopped more frequency of the inverter 3 continuously rapidly lowered in step S 5.

[0023]

Since the present invention is configured as described above, the following effects can be obtained.

(1 ) Since the retry is performed at the overcurrent level lower than the overcurrent protection level during the pick-up operation of the PM motor, the pick- up failure is reduced.

(2) Since the retry is repeated at the low overcurrent level, a secondary disaster such as destruction of the transistor element of the inverter main circuit can be prevented when the pickup fails.

[0026] (3) enables reliable pick by arbitrarily setting the number of retries picking physician up, picked stop can be reliably performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an inverter system.

FIG. 2 is a flowchart showing the contents of a pick-up operation process of the inverter.

FIG. 3 is a timing chart illustrating a pick-up operation.

FIG. 4 is a configuration diagram of an inverter system including an inverter dedicated to picking up and stopping.

FIG. 5 is a flowchart showing the contents of a pick-up stop process performed by a pick-up stop dedicated inverter.

FIG. 6 is a flowchart showing the contents of a conventional pick-up operation process.

[Explanation of symbols]

 1: Inverter 2: PM motor 3: Pickup dedicated inverter MC: Electromagnetic contactor

────────────────────────────────────────────────── ─── Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02P 5/408-5/412 H02P 7/628-7/632 H02P 7/74

Claims (3)

(57) [Claims] 1. When a PM motor driven by an inverter becomes free-run, the inverter detects an induced voltage of the PM motor, determines a phase of the induced voltage, and a phase substantially coincides with a phase of the voltage of the inverter. Output when PM
In performing the motor pick-up operation, it is determined whether or not the inflow current to the PM motor is at an overcurrent level after the execution of the pick-up operation. the overcurrent interrupt retry function to retry from the beginning to determine the post-retry number is provided, characterized in that as can be predetermined number of retries until current to the PM motor when the picking operation performed is below the overcurrent level top up how to pick up the PM motor in the inverter system that was. 2. When the PM motor driven by the inverter becomes free-run, the pick-up / stop dedicated inverter detects the induced voltage of the PM motor, determines the phase of the induced voltage, and determines that the phase is substantially equal to the voltage of the inverter. phase substantially matched in which the picking up execution of operations for picking stop the output to the PM motor from the pick stop inverter dedicated to PM motor case, current flowing into the picking operation performed after the PM motor overcurrent level The pickup operation is stopped when the current is equal to or higher than the overcurrent level, and the overcurrent cutoff retry function is provided to determine the number of retries after a predetermined time has elapsed and to retry the PM motor pickup from the beginning, and execute the pickup operation. that it has to be a predetermined number of retries until current to PM motor when it falls below the overcurrent level Top up how to pick up the PM motor in the inverter system and butterflies. 3. The overcurrent cutoff retry function according to claim 3, wherein the number of retries can be arbitrarily set.
1 or 2 above up how picking the PM motor in the inverter system according.