JP2767532B2 - Inverter overcurrent limit control method - Google Patents
Inverter overcurrent limit control methodInfo
- Publication number
- JP2767532B2 JP2767532B2 JP5140117A JP14011793A JP2767532B2 JP 2767532 B2 JP2767532 B2 JP 2767532B2 JP 5140117 A JP5140117 A JP 5140117A JP 14011793 A JP14011793 A JP 14011793A JP 2767532 B2 JP2767532 B2 JP 2767532B2
- Authority
- JP
- Japan
- Prior art keywords
- frequency
- output
- current
- inverter
- overload
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- Control Of Ac Motors In General (AREA)
- Inverter Devices (AREA)
Description
【０００１】[0001]
【産業上の利用分野】一般にインバ−タ運転で、運転中
に過負荷が生じ出力電流が増大すると出力周波数を下げ
ることで、過負荷あるいは過電流保護機能が動作し、イ
ンバ−タの停止を防止しているが、例えば出力側電動機
の並列運転において１台の電動機を運転中に他の電動機
を運転する場合の様な急激な負荷の増大が生じた場合、
出力周波数を低下させると同時に出力電圧も低下するた
め、出力電流は逆に増加し、過負荷電流レベル以上とな
りインバ−タが停止してしまう事がある。本発明はこの
ような急激な負荷に対してもインバ−タを停止させない
機能の改善に関するものである。BACKGROUND OF THE INVENTION Generally, in an inverter operation, when an overload occurs during the operation and the output current increases, the output frequency is lowered to activate an overload or overcurrent protection function, thereby stopping the inverter. Although it is prevented, for example, in the case of parallel operation of the output side motor, when a sudden increase in load occurs, such as when operating one motor while driving another motor,
Since the output voltage is also lowered at the same time as the output frequency is lowered, the output current increases conversely, exceeding the overload current level and stopping the inverter. The present invention relates to an improvement in the function of not stopping the inverter even under such a sudden load.
【０００２】[0002]
【従来の技術】図１は運転中に過負荷が生じた場合の出
力周波数と出力電流の関係を示す。時間ｔ1において過
負荷により出力電流が増大し規定値以上になると出力周
波数を下げて出力電流がバランスした周波数で運転を継
続し、時間ｔ2で過負荷状態が解消されると出力電流が
元の状態に戻り、これに応じて出力周波数が設定周波数
まで加速し運転を継続する。図２は急激な負荷の増大し
た場合を示し、負荷が増加し出力周波数が低下しても出
力電流が過負荷電流レベルを越え、過電流保護機能によ
りインバ−タが停止する。この様に出力周波数を下げる
と出力電流も下がるファンやポンプなどの二乗低減トル
ク特性の負荷の場合は出力電流が設定値以上になると出
力周波数を下げることは効果はあるが短時間に出力電流
が増大する急激な負荷に対しての場合は効果的でなかっ
た。2. Description of the Related Art FIG. 1 shows a relationship between an output frequency and an output current when an overload occurs during operation. At time t1, the output current increases due to overload, and when the output current exceeds a specified value, the output frequency is reduced and operation is continued at a frequency at which the output current is balanced. When the overload state is resolved at time t2, the output current returns to the original state. Then, in response to this, the output frequency accelerates to the set frequency and the operation is continued. FIG. 2 shows a case where the load suddenly increases. Even if the load increases and the output frequency decreases, the output current exceeds the overload current level, and the inverter stops due to the overcurrent protection function. In this way, when the output frequency is lowered, the output current also decreases.For loads with squared reduction torque characteristics such as fans and pumps, lowering the output frequency when the output current exceeds the set value is effective, but the output current decreases in a short time. It was not effective for increasing sudden loads.
【０００３】[0003]
【発明が解決しようとする課題】電動機の運転中、急激
な負荷による過負荷が生じた場合、出力周波数を下げる
と出力電流は更に増加し場合によっては過負荷電流レベ
ルを越え、過電流保護機能によりインバ−タが停止する
ことになりやすいなどの問題点がある。When an overload occurs due to a sudden load during the operation of the motor, the output current further increases when the output frequency is lowered, and in some cases, exceeds the overload current level. Therefore, there is a problem that the inverter is easily stopped.
【０００４】[0004]
【課題を解決するための手段】出力電流が過負荷電流の
規定値を越えるときに，不揮発性記憶素子に格納してあ
る過負荷電流の上下２段に設定した過負荷電流の検出レ
ベルのデータを読み出し，低い方の検出レベルでは出力
周波数を最大の減速レートで減速し，もう一つの高い方
の検出レベルを越えたときは，ただちに出力周波数を０
にして，一定停止時間後，電動機の回転数に同期した周
波数を低電圧から発生させ設定周波数迄加速運転をし，
同時に前記検出レベルのデータを不揮発性記憶素子に格
納し，出力電流が規定値になったとき，前記出力周波数
を設定周波数に戻す方法により解決を図った。 When the output current SUMMARY OF THE INVENTION exceeds a specified value of the overload current detection les overload current set at upper and lower stages of the overload current that is stored in the nonvolatile memory element
The read data is read out, and at the lower detection level, the output frequency is decelerated at the maximum deceleration rate . When the output level exceeds another higher detection level , the output frequency is set to 0 immediately.
After a certain stop time, a frequency synchronized with the rotation speed of the motor is generated from a low voltage and accelerated to the set frequency.
At the same time, the detection level data is stored in a non-volatile storage element, and when the output current reaches a specified value, the output frequency is returned to a set frequency to solve the problem.
【０００５】[0005]
【発明の作用】電動機の運転中、急激な負荷による過負
荷が生じた場合でもインバ−タが停止することを防ぎ、
円滑に運転していくことができる。According to the present invention, it is possible to prevent the inverter from stopping even when an overload occurs due to a sudden load during operation of the motor.
You can drive smoothly.
【０００６】[0006]
【実施例】本発明は従来と同じ回路構成から成立し、図
４はインバ−タ回路構成図を示すものであり、１が商用
交流電源でコンバ−タ部２で直流電圧に変換し、３は該
直流電圧を平滑する平滑用コンデンサで、４は直流を交
流に変換するインバ−タ部でインバ−タ部４を通して出
力が電動機５に印加される。６は制御部で駆動回路部
７、Ａ／Ｄ変換器８、インタ−フェ−ス回路９、ＣＰＵ
部１０、不揮発性記憶素子１１から構成されている。１
５は直流電流を電圧に変換する電流センサ−で、モ−タ
５の負荷電流の電流検知用で平滑コンデンサ３とインバ
−タ部４との間の直流電流を検知するよう設置されてい
る。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is realized from the same circuit configuration as that of the prior art, and FIG. 4 shows an inverter circuit configuration diagram, wherein 1 is a commercial AC power supply, which is converted into a DC voltage by an converter unit 2, and 3 Reference numeral 4 denotes a smoothing capacitor for smoothing the DC voltage. Reference numeral 4 denotes an inverter for converting DC to AC, and an output is applied to the motor 5 through the inverter 4. Reference numeral 6 denotes a control unit, which is a drive circuit unit 7, an A / D converter 8, an interface circuit 9, and a CPU.
The unit 10 includes a nonvolatile storage element 11. 1
Reference numeral 5 denotes a current sensor for converting a DC current to a voltage, which is provided for detecting the DC current between the smoothing capacitor 3 and the inverter section 4 for detecting the load current of the motor 5.
【０００７】周波数設定器１２で設定されたアナログ信
号である周波数設定用入力電圧はＡ／Ｄ変換器８に入力
され、デジタル信号に変換されてＣＰＵ部１０に入力さ
れる。一方運転スイッチ１３を閉路すると外部信号をア
イソレ−トするインタ−フェ−ス回路９を通してＣＰＵ
部１０に入力される。ＣＰＵ部１０は全ての演算処理を
行なうところで、演算結果や各種パラメ−タのデ−タを
格納した不揮発性記憶素子１１からデ−タを読み出して
演算処理を行なう。前記電流センサ−１５によりモ−タ
５の負荷電流はアナログ信号に変換され、前記Ａ／Ｄ変
換器８に入力され、次にＣＰＵ部１０に入力される。Ｃ
ＰＵ部１０から演算された信号は駆動回路部７に入力さ
れ、更に増幅されてインバ−タ部４を駆動する。The input voltage for frequency setting which is an analog signal set by the frequency setting device 12 is input to the A / D converter 8, converted into a digital signal, and input to the CPU section 10. On the other hand, when the operation switch 13 is closed, the CPU passes through the interface circuit 9 for isolating external signals.
Input to the unit 10. The CPU section 10 performs all arithmetic processing, and performs arithmetic processing by reading data from the nonvolatile storage element 11 which stores arithmetic results and data of various parameters. The load current of the motor 5 is converted into an analog signal by the current sensor 15, input to the A / D converter 8, and then input to the CPU 10. C
The signal calculated from the PU unit 10 is input to the drive circuit unit 7 and is further amplified to drive the inverter unit 4.
【０００８】図３に本発明による運転中に急激な負荷に
よる過電流が生じた場合の出力周波数と出力電流の関係
を示す。時間ｔ１で出力電流が低い方の電流の設定レベ
ルである設定レベル１を越え，設定周波数を下げると出
力電流はさらに増加して時間ｔ２で設定レベル２を越え
る。設定レベル２に達するとただちに出力周波数を０に
して一定時間後のｔ３に電動機の回転数に同期した周波
数を低電圧より発生させ設定周波数まで加速する。不揮
発性記憶素子１１内に運転中の電動機の出力電流の電流
値の設定レベルを上下２段に設定し，低い方のレベルで
は出力周波数を最大の減速レートで減速し，もう一つの
高い方のレベルではただちに出力周波数を０にして，一
定時間後電動機の回転数に同期した周波数を低電圧から
発生させ設定周波数まで加速しピックアップ運転する２
つの方法により解決を図るが，図５は本発明の運転中に
急激な負荷による過負荷が生じた場合のＣＰＵ部１０内
のデータ処理フローチャート図である。FIG. 3 shows the relationship between output frequency and output current when an overcurrent occurs due to a sudden load during operation according to the present invention. Exceeds a preset level 1 is a set level of current towards the output current is low at time t 1, the output current lowers the set frequency is further increased by the time t 2 exceeds the set level 2. The frequency synchronized immediately output frequency when a set level 2 reaches a rotation speed of the motor to t 3 after a predetermined time is set to 0 is generated from the low voltage to accelerate up to the set frequency. The current level of the output current of the motor during operation is set in the nonvolatile memory element 11 in two upper and lower stages. At the lower level, the output frequency is decelerated at the maximum deceleration rate, and at the other higher level. At the level, the output frequency is immediately set to 0, and after a certain period of time, a frequency synchronized with the rotation speed of the motor is generated from a low voltage, accelerated to the set frequency, and the pickup is operated.
FIG. 5 is a flowchart of data processing in the CPU section 10 when an overload due to a sudden load occurs during operation of the present invention.
【０００９】運転中の急激な負荷による過負荷電流が生
じると，電流センサー１５からＡ／Ｄ変換器８に入力さ
れ，次にＣＰＵ部１０に入力されるが，同時に不揮発性
記憶素子１１に格納してある過負荷電流の設定レベルを
上下２段に設定してある該過負荷電流のデータを読み出
す。過負荷電流が生じたときのＣＰＵ部１０内のデータ
処理は以下のようになる。ステップ１０２で出力周波数
を０にしたというＲＡＭ上の特定番地に立てたフラグで
ある停止中フラグがＯＮされているか判断をする。ステ
ップ１０２で停止中フラグがＯＮされていなければ，ス
テップ１０３で低い方の出力電流のレベルである設定レ
ベル１以上にあるかどうかの確認へ進む。設定レベル１
以上でない場合は通常の運転状態ということで，ステッ
プ１１４の出力周波数＝設定周波数へ設定する内容へ進
み，出力周波数が設定周波数であればその段階で終了と
なる。出力周波数が設定周波数でなければステップ１１
５で加速レートを設定して出力周波数を加速し，設定周
波数迄上昇する。ステップ１０２で停止中フラグがＯＮ
されていれば，ステップ１０８の停止タイマー＝０すな
わち停止時間が経過したかへ進む。When an overload current occurs due to a sudden load during operation, the overload current is input from the current sensor 15 to the A / D converter 8 and then to the CPU 10, but is simultaneously stored in the nonvolatile storage element 11. The data of the overload current in which the set level of the overload current is set in the upper and lower stages is read. The data processing in the CPU 10 when an overload current occurs is as follows. In step 102, it is determined whether or not a stop flag, which is a flag set at a specific address on the RAM indicating that the output frequency has been set to 0, is ON. If the stop flag is not turned on in step 102, the process proceeds to step 103 in which it is determined whether the output current is equal to or higher than the set level 1 which is the lower output current level. Setting level 1
If not, the operation is in a normal operation state, and the process proceeds to step 114 in which the output frequency is set to the set frequency. If the output frequency is the set frequency, the process ends at that stage. If the output frequency is not the set frequency, step 11
The output frequency is accelerated by setting the acceleration rate in step 5, and increases to the set frequency. The stop flag is ON in step 102
If so, the process proceeds to step 108 where the stop timer = 0, that is, whether the stop time has elapsed.
【００１０】ステップ１０３で設定レベル１以上であれ
ば、次にステップ１０４で高い方の出力電流のレヘ゛ル
である設定レベル２以上にあるかどうか確認し、設定レ
ベル２以上でない場合はステップ１１３で減速レ−トを
最大にして出力周波数を減少する方法で処理をして終了
する。If the level is equal to or higher than the set level 1 in step 103, it is checked in step 104 whether or not the level is higher than the set level 2 which is the level of the higher output current. Processing is performed in such a manner that the output frequency is reduced by maximizing the rate, and the processing is terminated.
【００１１】ステップ１０４で設定レベル２以上である
場合は、ステップ１０５で停止中フラグをセットして、
ステップ１０６で出力周波数＝０にセットする。出力周
波数＝０にセットされたら次にステップ１０７で設定レ
ベル２を決定するｔ２の時間を設定し、ｔ３迄ダウンカ
ウントするタイマ−でＲＡＭ上の特定番地である停止タ
イマ−に停止設定時間をセットする。設定レベル２は過
負荷電流レベルより小さく設定してあるので過電流保護
機能を動作させないですむ。If the level is equal to or higher than the set level 2 in step 104, a stop flag is set in step 105,
In step 106, the output frequency is set to zero. When the output frequency is set to 0, the time of t2 for determining the set level 2 is set at step 107, and the stop set time is set to the stop timer, which is a specific address on the RAM, by the timer for counting down until t3. I do. Since the setting level 2 is set smaller than the overload current level, it is not necessary to operate the overcurrent protection function.
【００１２】次にステップ１０８で停止タイマ−＝０、
すなわち停止時間が経過したかを判断する。停止時間が
経過すれば、ステップ１１０で電動機の回転数に同期し
た周波数を低電圧から発生させ、設定周波数まで加速す
るピックアップ操作を行なう。ステップ１１１で出力周
波数＝設定周波数に一致したとき、ステップ１１２で停
止中フラグをリセットし終了となる。Next, at step 108, the stop timer = 0,
That is, it is determined whether the stop time has elapsed. If the stop time has elapsed, in step 110, a frequency synchronized with the number of revolutions of the electric motor is generated from a low voltage, and a pickup operation for accelerating to a set frequency is performed. When the output frequency is equal to the set frequency in step 111, the stop flag is reset in step 112, and the process ends.
【００１３】ステップ１０８で停止タイマ−＝０でない
場合、すなわち停止時間が経過していなければ停止タイ
マ−のデ−タから一定値を減算し、その結果をＲＡＭ上
の特定番地である停止タイマ−にセットする。インバ−
タ部の出力電流が規定値になったときに、出力周波数の
デ−タを設定周波数に戻して不揮発性記憶素子１１に格
納する。If the stop timer is not "0" in step 108, that is, if the stop time has not elapsed, a constant value is subtracted from the data of the stop timer, and the result is stored in the stop timer which is a specific address on the RAM. Set to. Inver
When the output current of the data section reaches a specified value, the data of the output frequency is returned to the set frequency and stored in the nonvolatile memory element 11.
【００１４】[0014]
【発明の効果】不揮発性記憶素子１１内に過負荷電流の
検出レベルを上下２段に設定して，前期過負荷電流レベ
ルが下段を越えるときは前期過負荷電流の出力周波数を
最大の減速レートで低減し，前記過負荷電流レベルが上
段を検出したときは，ただちに出力周波数を０に設定
し，一定時間後に電動機の回転周波数に同期した周波数
から設定周波数まで上昇させることにより，部品点数を
増やさないで，インバータ運転中の過電流停止を防ぐこ
とができる。The detection level of the overload current is set in the upper and lower stages in the nonvolatile memory element 11, and when the overload current level exceeds the lower stage, the output frequency of the overload current is reduced. The output frequency is reduced at the maximum deceleration rate, and when the overload current level detects the upper stage, the output frequency is immediately set to 0, and after a certain time, the output frequency is increased from the frequency synchronized with the rotation frequency of the motor to the set frequency. The overcurrent stop during inverter operation can be prevented without increasing the number of parts.
以下次のように説明する。 The following is a description.
【図１】運転中に過負荷が生じた場合の出力周波数と出
力電流の関係を示した図。FIG. 1 is a diagram showing a relationship between an output frequency and an output current when an overload occurs during operation.
【図２】運転中に急激な負荷が生じた場合の出力周波数
と出力電流の関係を示した図。FIG. 2 is a diagram showing a relationship between an output frequency and an output current when a sudden load occurs during operation.
【図３】本発明による運転中に急激な負荷が生じた場合
の出力周波数と出力電流の関係を示した図。FIG. 3 is a diagram showing a relationship between an output frequency and an output current when a sudden load occurs during operation according to the present invention.
【図４】従来実施されているインバ−タ回路構成図。FIG. 4 is a configuration diagram of an inverter circuit conventionally implemented.
【図５】本発明の運転中に急激な負荷が生じた場合のＣ
ＰＵ部１０内のデ−タ処理フロチャ−ト図。FIG. 5 is a graph showing C when a sudden load occurs during operation of the present invention.
FIG. 4 is a data processing flowchart in the PU unit 10.
１ 商用交流電源 ２ コンバ−タ部 ３ 平滑コンデンサ ４ インバ−タ部 ５ 電動機 ６ 制御部 ７ 駆動回路部 ８ Ａ／Ｄ変換器 ９ インタ−フェ−ス回路 １０ ＣＰＵ部 １１ 不揮発性記憶素子 １２ 周波数設定器 １３ 運転スイッチ １５ 電流センサ− DESCRIPTION OF SYMBOLS 1 Commercial AC power supply 2 Converter part 3 Smoothing capacitor 4 Inverter part 5 Motor 6 Control part 7 Drive circuit part 8 A / D converter 9 Interface circuit 10 CPU part 11 Nonvolatile storage element 12 Frequency setting Container 13 Operation switch 15 Current sensor
Claims (1)
ータ部と，該コンバータ部で変換した直流を交流出力に
変換するインバータ部と，該インバータ部をパルス幅制
御するＣＰＵ部を有する制御部と，前記インバータ出力
に接続した交流電動機の負荷電流に応じて周波数を制御
する機能を有するインバータにおいて，前記交流電動機
の負荷電流が過負荷電流の規定値を越えるときに，不揮
発性記憶素子に格納してある上下２段に設定した過負荷
電流の検出レベルと，該過負荷電流のデータを読み出す
手段と，前記過負荷電流の検出レベルが下段を越えると
きは前記過負荷電流の出力周波数を最大の減速レートで
周波数を低減する手段と，前記過負荷電流が急激な負荷
により上段検出レベルを越えたときは，ただちに出力周
波数を０に設定し，一定時間後に電動機の回転周波数に
同期した周波数から設定周波数迄上昇させる手段と，前
記インバータ部の出力電流が規定値になったときに出力
周波数のデータを設定周波数に戻して不揮発性記憶素子
に格納する手段よりなるインバータの過電流制限制御方
法。A converter for converting a commercial AC power supply into a DC power; an inverter for converting the DC converted by the converter to an AC output; a control unit having a CPU for controlling the pulse width of the inverter; in the inverter having the function of controlling the frequency in accordance with the load current of the AC motor connected to the inverter output, the load current of the AC motor when exceeding the specified value of the overload current, and stored in the nonvolatile memory element Overload set in upper and lower two stages
Means for reading a current detection level and the data of the overload current ; means for reducing the output frequency of the overload current at a maximum deceleration rate when the detection level of the overload current exceeds a lower level; The load where the overload current is sudden
When the output level exceeds the upper detection level, the output frequency is immediately set to 0, and after a certain period of time, means for increasing the frequency from the frequency synchronized with the rotation frequency of the motor to the set frequency, and the output current of the inverter section becomes the specified value. And a method of returning the output frequency data to the set frequency and storing the output frequency data in the nonvolatile storage element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5140117A JP2767532B2 (en) | 1993-05-19 | 1993-05-19 | Inverter overcurrent limit control method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5140117A JP2767532B2 (en) | 1993-05-19 | 1993-05-19 | Inverter overcurrent limit control method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06335289A JPH06335289A (en) | 1994-12-02 |
| JP2767532B2 true JP2767532B2 (en) | 1998-06-18 |
Family
ID=15261312
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5140117A Expired - Fee Related JP2767532B2 (en) | 1993-05-19 | 1993-05-19 | Inverter overcurrent limit control method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2767532B2 (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04299096A (en) * | 1991-03-27 | 1992-10-22 | Mitsubishi Electric Corp | Elevator door controller |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07108116B2 (en) * | 1987-07-28 | 1995-11-15 | 松下電工株式会社 | Electric motor controller |
-
1993
- 1993-05-19 JP JP5140117A patent/JP2767532B2/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04299096A (en) * | 1991-03-27 | 1992-10-22 | Mitsubishi Electric Corp | Elevator door controller |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH06335289A (en) | 1994-12-02 |
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| LAPS | Cancellation because of no payment of annual fees |