JPH04127898A - Method for switching operating state of inverter - Google Patents
Method for switching operating state of inverterInfo
- Publication number
- JPH04127898A JPH04127898A JP2247905A JP24790590A JPH04127898A JP H04127898 A JPH04127898 A JP H04127898A JP 2247905 A JP2247905 A JP 2247905A JP 24790590 A JP24790590 A JP 24790590A JP H04127898 A JPH04127898 A JP H04127898A
- Authority
- JP
- Japan
- Prior art keywords
- inverter
- operating state
- carrier frequency
- state
- time
- 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.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims description 9
- 230000006698 induction Effects 0.000 claims description 8
- 230000007423 decrease Effects 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 4
- 238000007796 conventional method Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000007704 transition Effects 0.000 description 1
Landscapes
- Stopping Of Electric Motors (AREA)
- Control Of Ac Motors In General (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、誘導電動機を速度制御する電圧形ＰＷＭイン
バータの該電動機に対する直流制動状態からインバータ
運転状態への運転状態切替方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of switching the operating state of a voltage-type PWM inverter that controls the speed of an induction motor from a DC braking state to an inverter operating state.
従来のこの種のインバータの運転状態切替方法としては
、その負荷誘導電動機に対する前記インバータのキャリ
ア周波数変更を伴う直流制動状態からインバータ運転状
態への運転状態切替時、該両状態間に前記インバータの
動作停止期間２例えばトランジスタ式インバータにあっ
てはその主回路を構成するスイッチングトランジスタに
対するベースしゃ新期間、を設けずに前記の如き運転状
態の切替えを行うものが知られている。As a conventional method for switching the operating state of this type of inverter, when switching the operating state from a DC braking state to an inverter operating state accompanied by a change in the carrier frequency of the inverter for the load induction motor, the operation of the inverter is changed between the two states. Stop period 2 For example, in the case of a transistor type inverter, it is known that the above-mentioned operating state is switched without providing a base renewal period for the switching transistors constituting the main circuit thereof.
しかしながら上記の如き従来のインバータの運転状態切
替方法においては、前記電動機の直流制動時の低騒音化
を図るために該制動時のキャリア周波数の高周波化を行
えば、インバータ運転始動時と前記直流制動時とのキャ
リア周波数の差が大となり、前記電動機の残留電圧が高
い状態のまま低キャリア周波数のインバータ運転への切
替えが行われ、インバータ出力電流過大の異常状態を招
く危険があり、従って前記直流制動時キャリア周、波数
の増大は制約され該直流制動時における前記電動機の低
騒音化には限界があった。However, in the conventional inverter operating state switching method as described above, in order to reduce noise during DC braking of the motor, if the carrier frequency during braking is increased, it is possible to The difference in the carrier frequency between the DC and DC currents becomes large, and switching to inverter operation with a low carrier frequency is performed while the residual voltage of the motor remains high. The increase in carrier frequency and wave number during braking is restricted, and there is a limit to the reduction in noise of the motor during direct current braking.
第２図は上記の模様を示すものであり、図（イ）と図（
ロ）とはそれぞれキャリア周波数ｆ Ｃ＋電圧ＶＣのキ
ャリア信号とインバータ出力電流Ｉ。Figure 2 shows the above pattern, Figure (A) and Figure (
b) are the carrier signal of carrier frequency f C + voltage VC and the inverter output current I, respectively.
との動作波形図の例示である。第２図（イ）において、
運転状態切替時刻ｔ１以前は高キャリア周波数域（例え
ばｆｃ−３ｋＨｚ ）であり前記電動機の直流制動状態
に対応し、前記時刻ｔ、以降は低キャリア周波数域（例
えばｆｃ＝ ３００）（ｚ）であり前記電動機のインバ
ータ運転状態を示す。第２図（ロ）は前記図（イ）に対
応し、インバータ出力電流■、が前記時刻ｔ１において
その上限設定値ｌｉｐを過渡的に超過する模様を示すも
のであり、通常この電流超過時点で前記インバータに対
する運転停止保護が行われる。This is an example of an operation waveform diagram. In Figure 2 (a),
Before the operating state switching time t1, the frequency is in a high carrier frequency range (for example, fc-3kHz), which corresponds to the DC braking state of the motor, and after the time t, it is in a low carrier frequency range (for example, fc = 300) (z). The inverter operating state of the electric motor is shown. Figure 2 (b) corresponds to the above figure (a) and shows that the inverter output current ■ transiently exceeds its upper limit set value lip at the time t1, and normally at the time of this current excess. Operation stop protection is performed for the inverter.
上記に鑑み本発明は、誘導電動機のＰＷＭインバータに
よる直流制動状態からインバータ運転への切替えを該両
状態のキャリア周波数の差の大なる場合にも円滑に行い
得るインバータの運転状態切替方法の提供を目的とする
ものである。In view of the above, the present invention provides an inverter operating state switching method that can smoothly switch an induction motor from a DC braking state using a PWM inverter to inverter operation even when there is a large difference in carrier frequency between the two states. This is the purpose.
上記目的を達成するために、本発明のインバータの運転
状態切替方法は、誘導電動機の速度制御を行う電圧形Ｐ
ＷＭインバータにおいて、前記電動機に対する高キャリ
ア周波数による直流制動状態から低キャリア周波数によ
るインバータ運転状態へ切替える際に該前状態間に前記
インバータの動作停止期間を設けるものとし、更に該イ
ンバータの動作停止期間を、前記電動機の制動特性に従
って決定される許容最大停止時間から前記高低両キャリ
ア周波数間の周波数差に逆比例する値として得られた補
正時間を減算した値となすものとする。In order to achieve the above object, the inverter operating state switching method of the present invention provides a voltage source P for controlling the speed of an induction motor.
In the WM inverter, when switching the electric motor from a DC braking state using a high carrier frequency to an inverter operating state using a low carrier frequency, an operation stop period of the inverter is provided between the previous states, and an operation stop period of the inverter is further provided. , shall be the value obtained by subtracting the correction time obtained as a value inversely proportional to the frequency difference between the high and low carrier frequencies from the allowable maximum stop time determined according to the braking characteristics of the motor.
前記の如く、インバータのその負荷誘導電動機に対する
直流制動状態からインバータ運転状態への切替え時に、
該前状態間のキャリア周波数の差が大なる場合における
インバータ出力電流の過電流状態の発生は前記電動機の
残留電圧に起因するものである。As mentioned above, when the inverter switches its load induction motor from the DC braking state to the inverter operating state,
The occurrence of an overcurrent state in the inverter output current when the carrier frequency difference between the previous states is large is caused by the residual voltage of the motor.
上記に従い本発明は、前記の如き再運転状態の切替え時
に該前状態間に前記インバータの動作停止期間を設けて
前記残留電圧の減衰を待つものであり、且つ該動作停止
期間を前記キャリア周波数の差に応じて変化させ、下記
の式（１）により規定される時間となすものである。In accordance with the above, the present invention provides an operation stop period of the inverter between the previous states when switching the re-operation state as described above to wait for the residual voltage to decay, and also sets the operation stop period to the carrier frequency. The time is changed according to the difference, and the time is defined by the following equation (1).
但し、Ｔ４は前記インバータの動作停止時間、Ｔ４゜は
該Ｔ、の許容最大値、Ｋは定数、Δｆｃはキャリア周波
数差、ｆｅｂは直流制動時のキャリア周波数、ｆｃｉは
インバータ運転時のキャリア周波数である。However, T4 is the operation stop time of the inverter, T4° is the maximum allowable value of T, K is a constant, Δfc is the carrier frequency difference, feb is the carrier frequency during DC braking, and fci is the carrier frequency during inverter operation. be.
上記式（１）の示す通り、Δｆ、 ＝に／Ｔａ。にてＴ
４＝０となり、以後Δｆ、の増大と共にＴ４は増大する
。As shown in the above formula (1), Δf, =/Ta. At T
4=0, and thereafter T4 increases as Δf increases.
第１図は、本発明に従って前記の如きインバータの直流
制動状態からインバータ運転状態への切替え時に、該前
状態間に前記式（１）に従う時間Ｔ４の動作停止期間を
設けた場合の動作波形図の例示であり、図（イ）はキャ
リア周波数ｆｃ、電圧ｖｃの三角波キャリア信号の該周
波数ｆｃの変更模様を示し、時刻１．以前は高キャリア
周波数域（例えばｆｃ＝３ｋＨｚ ）であり前記電動機
の直流制動状態に対応し、時刻ｔ２以降は低キャリア周
波数（例えばｆｃ＝ ３００Ｈｚ）に切替えてインバー
タ運転となし、前記同時刻ｔ、とｔ２との間に継続時間
Ｔａ （Ｔ４＝ ｔｚ ｔ＋）のインバータ動作停止
期間を設けた状態を示すものである。なお図中、前記イ
ンバータ動作停止期間はトランジスタ式インバータを例
にベースしゃ断の期間として示している０次に第１図の
図（ロ）は同図（イ）に対応したインバータ出力電流１
．の変化模様を示すものであり、Ｔａ＝０となした前記
第２図の図（ロ）の場合と異り、時刻ｔ１にて前記電流
Ｉ□はその上限設定値１ ｉｐを超えることなく急速に
零に至り、前記時刻ｔ２以降指定された正常な値にて再
出力され、前記の直流制動状態からインバータ運転状態
への円滑な切替移行が行われていることを示すものであ
る。FIG. 1 is an operation waveform diagram when an operation stop period of time T4 according to the formula (1) is provided between the previous states when switching from the DC braking state of the inverter to the inverter operating state according to the present invention. Figure (a) shows a change pattern of the frequency fc of a triangular wave carrier signal of carrier frequency fc and voltage vc, and shows a change pattern of the frequency fc at time 1. Previously, it was in a high carrier frequency range (for example, fc = 3 kHz), corresponding to the DC braking state of the motor, and after time t2, it was switched to a low carrier frequency (for example, fc = 300 Hz) to perform inverter operation, and at the same time t, This shows a state in which an inverter operation stop period of duration Ta (T4=tz t+) is provided between and t2. In the figure, the inverter operation stop period is shown as a base cut-off period using a transistor type inverter as an example. Figure (B) in Figure 1 shows the inverter output current 1 corresponding to Figure (A).
．． This shows the pattern of change in the current I□ at time t1, which rapidly increases without exceeding its upper limit setting value 1ip, unlike the case of the diagram (b) in FIG. 2 where Ta=0. It reaches zero, and is re-outputted at the specified normal value after the time t2, indicating that a smooth transition from the DC braking state to the inverter operating state is being performed.
本発明によれば、誘導電動機の速度制御を行うｔ正形Ｐ
ＷＭインバータにおいて、前記電動機に対する高キャリ
ア周波数による直流制動状態から低キャリア周波数によ
るインバータ運転状態へ切替える際に該両状態間に前記
インバータの動作停止期間を設け、且つ該停止期間を、
前記電動機の制動特性に従って決定される許容最大停止
時間から前記高低両キャリア周波数間の周波数差に逆比
例する値として得られた補正時間を減算した値となすこ
とにより、前記周波数差に応じた適当な期間にわたる前
記電動機残留電圧の適当な低減が図られ、前記インバー
タの両状態間の切替えを該インバータの出力電流過大状
態を招くことなく円滑に行うことができる。According to the present invention, the t-shaped P that controls the speed of the induction motor
In the WM inverter, when switching the electric motor from a DC braking state using a high carrier frequency to an inverter operating state using a low carrier frequency, an operation stop period of the inverter is provided between the two states, and the stop period is
By subtracting the correction time obtained as a value inversely proportional to the frequency difference between the high and low carrier frequencies from the allowable maximum stop time determined according to the braking characteristics of the motor, an appropriate adjustment can be made according to the frequency difference. The residual voltage of the motor is appropriately reduced over a period of time, and the inverter can be smoothly switched between the two states without causing an excessive output current of the inverter.
第１図と第２図とは、インバータによるその負荷誘導電
動機の直流制動状態からインバータ運転への切替え時に
おけるキャリア信号とインバータ出力電流との動作波形
図であり、第１図は本発明の方法に従う場合、第２図は
従来の方法による場合を示す。1 and 2 are operational waveform diagrams of the carrier signal and the inverter output current when the inverter switches the load induction motor from a DC braking state to inverter operation, and FIG. 1 shows the method of the present invention. If the following is followed, FIG. 2 shows the case according to the conventional method.
Claims (1)
タにおいて、前記電動機に対する高キャリア周波数によ
る直流制動状態から低キャリア周波数によるインバータ
運転状態へ切替える際に該両状態間に前記インバータの
動作停止期間を設けたことを特徴とするインバータの運
転状態切替方法。 ２）請求項１記載のインバータの運転状態切替方法にお
いて、前記インバータの動作停止期間を、前記電動機の
制動特性に従って決定される許容最大停止時間から前記
高低両キャリア周波数間の周波数差に逆比例する値とし
て得られた補正時間を減算した値となしたことを特徴と
するインバータの運転状態切替方法。[Scope of Claims] 1) In a voltage source PWM inverter that controls the speed of an induction motor, when the motor is switched from a DC braking state with a high carrier frequency to an inverter operating state with a low carrier frequency, the inverter is A method for switching an operating state of an inverter, characterized by providing an operation stop period. 2) In the inverter operating state switching method according to claim 1, the operation stop period of the inverter is inversely proportional to the frequency difference between the high and low carrier frequencies from the allowable maximum stop time determined according to the braking characteristics of the electric motor. A method for switching an operating state of an inverter, characterized in that a value is obtained by subtracting a correction time obtained as a value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2247905A JPH04127898A (en) | 1990-09-18 | 1990-09-18 | Method for switching operating state of inverter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2247905A JPH04127898A (en) | 1990-09-18 | 1990-09-18 | Method for switching operating state of inverter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04127898A true JPH04127898A (en) | 1992-04-28 |
Family
ID=17170304
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2247905A Pending JPH04127898A (en) | 1990-09-18 | 1990-09-18 | Method for switching operating state of inverter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04127898A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5744927A (en) * | 1994-01-28 | 1998-04-28 | Mitsubishi Denki Kabushiki Kaisha | Inverter control method and apparatus |
-
1990
- 1990-09-18 JP JP2247905A patent/JPH04127898A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5744927A (en) * | 1994-01-28 | 1998-04-28 | Mitsubishi Denki Kabushiki Kaisha | Inverter control method and apparatus |
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