JP3715277B2

JP3715277B2 - Active filter device

Info

Publication number: JP3715277B2
Application number: JP2002378573A
Authority: JP
Inventors: 正二羽田
Original assignee: 株式会社エヌ・ティ・ティ・データ・イー・エックス・テクノ
Priority date: 2002-12-26
Filing date: 2002-12-26
Publication date: 2005-11-09
Anticipated expiration: 2022-12-26
Also published as: JP2004215324A

Description

【０００１】
【発明の属する技術分野】
この発明は、商用電源と負荷との間に挿入され、電流補償、力率改善などを行うアクティブフィルタ装置に関するものであり、特に、装置の構成が簡易であり、かつ、応答速度に優れたアクティブフィルタ装置に関するものである。
【０００２】
【従来の技術】
最近の家電機器、例えば、パソコン、冷蔵庫、エアコン、照明器具などにおいては、その内部にインバータ電源が組み込まれている。このインバータ電源が組み込まれた機器は、５０Ｈｚ／６０Ｈｚの切り換えが不要であるとか、静音、省電力といった特徴を有しているので、今後、さらに、利用が促進されて行くものと予想される。一方、このインバータ電源が組み込まれた機器は、負荷に流れる高調波電流によって、負荷の力率を悪化させ、電力の利用効率を低下させるといった弊害も問題視されている。
【０００３】
これらの問題を解決する従来技術として、例えば、特許文献１に記載されたアクティブフィルタ装置がある。この文献に記載されたアクティブフィルタ装置は、補償能力判定器、力率改善補償電流制御回路、無効電流補償電流制御回路、補償電流制御回路などを備え、補償能力判定器が、インバータの直流側に接続された直流電源装置の電圧に基づいてインバータで発生可能な補償電流の余剰補償能力を判定し、力率改善補償電流制御回路が、補償能力判定器で判定された余剰補償能力に見合った力率改善補償電流を算出し、一方、無効電流補償電流制御回路が、その余剰補償能力に見合った無効電流補償電流を算出し、補償電流制御回路が、高調波補償電流と力率改善補償電流あるいは高調波補償電流と無効電流補償電流に基づいて補償電流を算出してインバータに制御指令を出すことで、高調波電流の補償や力率改善補償を行っている。
【０００４】
【特許文献１】
特開平８−１４０２６７号公報（第３−５頁、図１）
【０００５】
【発明が解決しようとする課題】
ところで、上述した従来技術のアクティブフィルタ装置では、電源系統に流れる基本波電流を検出する回路および高調波電流を検出する回路、電源電圧の位相信号と基本波電流とから運転力率を検出する回路、補償電流を発生させる回路、その他、位相反転回路、位相シフト回路、加算器、掛け算器等の多種多様の回路が用いられているので、装置構成が複雑であり、そのため、装置が高価であるという欠点を有していた。また、補償電流を発生させるために信号波形の波形解析が必須なので、応答速度が遅いという問題点があった。
【０００６】
この発明は、上記に鑑みてなされたものであって、装置構成が簡単であり、波形解析等の手段を特に必要とせず応答速度に優れたアクティブフィルタ装置を得ることを目的とする。
【０００７】
【課題を解決するための手段】
上述した課題を解決し、目的を達成するために、この発明にかかるアクティブフィルタ装置は、商用電源に接続された負荷から発生する高調波電流を補償するための補償電流の送出／引込を行うインバータと、該インバータの直流側に接続されて前記補償電流の供給源となる補償電流供給手段と、前記インバータを制御するための制御手段とを備えたアクティブフィルタ装置において、前記制御手段は、前記商用電源に流れる電流成分を検出する商用電流検出手段と、前記商用電源の電圧成分を検出する商用電圧検出手段と、前記商用電流検出手段が検出した商用電流検出信号を増幅する電流検出信号増幅器と、を備え、前記電流検出信号増幅器の出力信号と前記商用電圧検出手段が検出した商用電圧検出信号との合成信号に基づいて前記インバータが制御され、前記インバータが行う前記補償電流の送出／引込制御が、該補償電流に基づいた前記電流検出信号増幅器の利得制御によって行われることを特徴とする。
【０００８】
この発明によれば、商用電源に流れる電流成分を検出する商用電流検出手段と、商用電源の電圧成分を検出する商用電圧検出手段とを具備する制御手段には、商用電流検出手段が検出した商用電流検出信号を増幅する電流検出信号増幅器が備えられ、電流検出信号増幅器の出力信号と商用電圧検出手段が検出した商用電圧検出信号との合成信号に基づいてインバータが制御され、インバータが行う補償電流の送出／引込制御が、補償電流に基づく電流検出信号増幅器の利得制御によって行われる。
【００１３】
商用電源に接続された負荷から発生する高調波電流を補償するための補償電流の送出／引込を行うインバータと、該インバータの直流側に接続されて前記補償電流の供給源となる補償電流供給手段と、前記インバータを制御するための制御手段とを備えたアクティブフィルタ装置において、前記制御手段は、前記商用電源に流れる電流成分を検出する商用電流検出手段と、前記商用電源の電圧成分を検出する商用電圧検出手段と、前記商用電圧検出手段が検出した商用電圧検出信号を増幅する電圧検出信号増幅器と、を備え、前記電圧検出信号増幅器の出力信号と前記商用電流検出手段が検出した商用電流検出信号との合成信号に基づいて前記インバータが制御され、前記補償電流供給手段の充電量の制御が、該補償電流供給手段の端子電圧に基づいた前記電圧検出信号増幅器の利得制御によって行われることを特徴とする。
【００１４】
この発明によれば、商用電源に流れる電流成分を検出する商用電流検出手段と、商用電源の電圧成分を検出する商用電圧検出手段とを具備する制御手段には、商用電圧検出手段が検出した商用電圧検出信号を増幅する電圧検出信号増幅器が備えられ、電圧検出信号増幅器の出力信号と商用電流検出手段が検出した商用電流検出信号との合成信号に基づいてインバータが制御され、補償電流供給手段の充電量の制御が、補償電流供給手段の端子電圧に基づいた電圧検出信号増幅器の利得制御によって行われる。
【００１５】
商用電源に接続された負荷から発生する高調波電流を補償するための補償電流の送出／引込を行うインバータと、該インバータの直流側に接続されて前記補償電流の供給源となる補償電流供給手段と、前記インバータを制御するための制御手段とを備えたアクティブフィルタ装置において、前記制御手段は、前記商用電源に流れる電流成分を検出する商用電流検出手段と、前記商用電源の電圧成分を検出する商用電圧検出手段と、前記商用電流検出手段が検出した商用電流検出信号を増幅する電流検出信号増幅器と、前記商用電圧検出手段が検出した商用電圧検出信号を増幅する電圧検出信号増幅器と、を備え、前記電流検出信号増幅器の出力信号と前記電圧検出信号増幅器の出力信号との合成信号に基づいて前記インバータが制御され、前記インバータが行う前記補償電流の送出／引込制御が、該補償電流に基づいた前記電流検出信号増幅器の利得制御によって行われ、前記補償電流供給手段の充電量の制御が、該補償電流供給手段の端子電圧に基づいた前記電圧検出信号増幅器の利得制御によって行われることを特徴とする。
【００１６】
この発明によれば、商用電源に流れる電流成分を検出する商用電流検出手段と、商用電源の電圧成分を検出する商用電圧検出手段とを具備する制御手段には、商用電流検出手段が検出した商用電流検出信号を増幅する電流検出信号増幅器と、商用電圧検出手段が検出した商用電圧検出信号を増幅する電圧検出信号増幅器とが備えられ、電流検出信号増幅器の出力信号と電圧検出信号増幅器の出力信号との合成信号に基づいてインバータが制御され、インバータが行う補償電流の送出／引込制御が、補償電流に基づく電流検出信号増幅器の利得制御によって行われるとともに、補償電流供給手段の充電量の制御が、補償電流供給手段の端子電圧に基づいた電圧検出信号増幅器の利得制御によって行われる。
【００１７】
商用電源に接続された負荷から発生する位相遅れ／進み電流を補償するための補償電流の送出／引込を行うインバータと、該インバータの直流側に接続されて前記補償電流の供給源となる補償電流供給手段と、前記インバータを制御するための制御手段とを備えたアクティブフィルタ装置において、前記制御手段は、前記商用電源に流れる電流成分を検出する商用電流検出手段と、前記商用電源の電圧成分を検出する商用電圧検出手段と、前記商用電流検出手段が検出した商用電流検出信号を増幅する電流検出信号増幅器と、を備え、前記電流検出信号増幅器の出力信号と前記商用電圧検出手段が検出した商用電圧検出信号との合成信号に基づいて前記インバータが制御され、前記インバータが行う前記補償電流の送出／引込制御が、該補償電流に基づいた前記電流検出信号増幅器の利得制御によって行われることを特徴とする。
【００１８】
この発明によれば、商用電源に流れる電流成分を検出する商用電流検出手段と、商用電源の電圧成分を検出する商用電圧検出手段とを具備する制御手段には、商用電流検出手段が検出した商用電流検出信号を増幅する電流検出信号増幅器が備えられ、電流検出信号増幅器の出力信号と商用電圧検出手段が検出した商用電圧検出信号との合成信号に基づいてインバータが制御され、インバータが行う補償電流の送出／引込制御が、補償電流に基づく電流検出信号増幅器の利得制御によって行われる。
【００１９】
商用電源に接続された負荷から発生する位相遅れ／進み電流を補償するための補償電流の送出／引込を行うインバータと、該インバータの直流側に接続されて前記補償電流の供給源となる補償電流供給手段と、前記インバータを制御するための制御手段とを備えたアクティブフィルタ装置において、前記制御手段は、前記商用電源に流れる電流成分を検出する商用電流検出手段と、前記商用電源の電圧成分を検出する商用電圧検出手段と、前記商用電圧検出手段が検出した商用電圧検出信号を増幅する電圧検出信号増幅器と、を備え、前記電圧検出信号増幅器の出力信号と前記商用電流検出手段が検出した商用電流検出信号との合成信号に基づいて前記インバータが制御され、前記補償電流供給手段の充電量の制御が、該補償電流供給手段の端子電圧に基づいた前記電圧検出信号増幅器の利得制御によって行われることを特徴とする。
【００２０】
この発明によれば、商用電源に流れる電流成分を検出する商用電流検出手段と、商用電源の電圧成分を検出する商用電圧検出手段とを具備する制御手段には、商用電圧検出手段が検出した商用電圧検出信号を増幅する電圧検出信号増幅器が備えられ、電圧検出信号増幅器の出力信号と商用電流検出手段が検出した商用電流検出信号との合成信号に基づいてインバータが制御され、補償電流供給手段の充電量の制御が、補償電流供給手段の端子電圧に基づいた電圧検出信号増幅器の利得制御によって行われる。
【００２１】
商用電源に接続された負荷から発生する位相遅れ／進み電流を補償するための補償電流の送出／引込を行うインバータと、該インバータの直流側に接続されて前記補償電流の供給源となる補償電流供給手段と、前記インバータを制御するための制御手段とを備えたアクティブフィルタ装置において、前記制御手段は、前記商用電源に流れる電流成分を検出する商用電流検出手段と、前記商用電源の電圧成分を検出する商用電圧検出手段と、前記商用電流検出手段が検出した商用電流検出信号を増幅する電流検出信号増幅器と、前記商用電圧検出手段が検出した商用電圧検出信号を増幅する電圧検出信号増幅器と、を備え、前記電流検出信号増幅器の出力信号と前記電圧検出信号増幅器の出力信号との合成信号に基づいて前記インバータが制御され、前記インバータが行う前記補償電流の送出／引込制御が、該補償電流に基づいた前記電流検出信号増幅器の利得制御によって行われ、前記補償電流供給手段の充電量の制御が、該補償電流供給手段の端子電圧に基づいた前記電圧検出信号増幅器の利得制御によって行われることを特徴とする。
【００２２】
この発明によれば、商用電源に流れる電流成分を検出する商用電流検出手段と、商用電源の電圧成分を検出する商用電圧検出手段とを具備する制御手段には、商用電流検出手段が検出した商用電流検出信号を増幅する電流検出信号増幅器と、商用電圧検出手段が検出した商用電圧検出信号を増幅する電圧検出信号増幅器とが備えられ、電流検出信号増幅器の出力信号と電圧検出信号増幅器の出力信号との合成信号に基づいてインバータが制御され、インバータが行う補償電流の送出／引込制御が、補償電流に基づく電流検出信号増幅器の利得制御によって行われるとともに、補償電流供給手段の充電量の制御が、補償電流供給手段の端子電圧に基づいた電圧検出信号増幅器の利得制御によって行われる。
【００２３】
前記補償電流供給手段は、コンデンサで構成されることを特徴とする。
【００２４】
この発明によれば、コンデンサを用いてアクティブフィルタ装置を簡易に構成することができる。
【００２５】
【発明の実施の形態】
以下、この発明にかかるアクティブフィルタ装置の実施の形態を図面に基づいて詳細に説明する。なお、この実施の形態によりこの発明が限定されるものではない。
【００２６】
図１は、この発明の実施の形態にかかる回路構成を示す図である。同図において、入力端子と出力端子とをそれぞれ有したアクティブフィルタ装置１０は、電圧トランスＰＴ、電流トランスＣＴ１、ＣＴ２、可変利得電圧制御アンプＡＧＣ１、ＡＧＣ２、反転回路ＰＲ１、加算回路ＳＵＭ１、双方向インバータＩＮＶ１、ダイオードＤ１およびコンデンサＣ１、Ｃ２を備えている。アクティブフィルタ装置１０の入力端子には商用電源が接続され、出力端子には負荷が接続されている。
【００２７】
つぎに、実施の形態にかかるアクティブフィルタ装置１０の回路構成について説明する。図１において、電圧トランスＰＴは、一次巻線および二次巻線を備えている。電圧トランスＰＴの一次巻線は、アクティブフィルタ装置１０内の電源ラインに接続される。また、二次巻線は、反転回路ＰＲ１に接続される。電流トランスＣＴ１は、アクティブフィルタ装置１０内の電源ラインの一端上で、電源ラインに挿入させることなく電源ラインに流れる電流を検出するため、電源ライン（給電線）を挟み込んで接続される。加算回路ＳＵＭ１は、入力側が電流トランスＣＴ１に接続された可変利得電圧制御アンプＡＧＣ１と反転回路ＰＲ１に接続された可変利得電圧制御アンプＡＧＣ２とに接続され、出力側は双方向インバータＩＮＶ１と接続される。
【００２８】
双方向インバータＩＮＶ１は、一対の直流側端子ＤＴ１、ＤＴ２と、一対の交流側端子ＡＴ１、ＡＴ２とを備えている。双方向インバータＩＮＶ１の交流側端子ＡＴ１は、一方の電源ラインに接続され、交流側端子ＡＴ２は、他方の電源ラインに接続される。双方向インバータＩＮＶ１の直流側端子ＤＴ１は、コンデンサＣ１の一端と接続され、直流側端子ＤＴ２は、コンデンサＣ１の他端（同時に回路グランドにも接地されている接地端）に接続される。また、双方向インバータＩＮＶ１の直流側端子ＤＴ１と接続されたコンデンサＣ１の一端は、可変利得電圧制御アンプＡＧＣ２にも接続される。双方向インバータＩＮＶ１の直流側端子ＤＴ１と一方の電源ラインとを接続するライン上には、ダイオードＤ１のアノードと接続された電流トランスＣＴ２が、このラインを挟み込んで接続される。ダイオードＤ１のカソードは、可変利得電圧制御アンプＡＧＣ１に接続されるとともに、コンデンサＣ２の一端にも接続される。コンデンサＣ２の他端は、コンデンサＣ１と同様に回路グランドに設置される。
【００２９】
つぎに、図１に示すアクティブフィルタ装置１０の動作について説明する。同図に図示したＩ１、Ｉ２、Ｉ３は、それぞれ、商用電源側に流れる商用電流、双方向インバータＩＮＶ１から出力されるインバータ電流、負荷側に流れる負荷電流を表している。ところで、同図からも明らかなように、商用電源と負荷との間には、商用電源を給電する電源ライン上に電流トランスＣＴ１が存在するのみである。電流トランスＣＴ１は、電源ラインに挿入されることなく、負荷に流れる電流を検出するものであり、商用電源と負荷との間の動作に影響を与えることはない。したがって、このアクティブフィルタ装置１０が商用電源や負荷に対して何も作用しないとき、すなわち、インバータ電流Ｉ２が流れないときは、商用電流がそのまま負荷電流となる。
【００３０】
図１において、電圧トランスＰＴは、商用電源が供給した電源電圧Ｖｉｎを検出し、電流トランスＣＴ１は、電源ラインに流れる商用電流Ｉ１を検出する。電圧トランスＰＴで検出された電圧信号は、反転回路ＰＲ１で反転され、可変利得電圧制御アンプＡＧＣ２に入力される。一方、電流トランスＣＴ１で検出された電流信号は、そのまま可変利得電圧制御アンプＡＧＣ１に入力される。これらの信号は、可変利得電圧制御アンプＡＧＣ１、ＡＧＣ２によって増幅され、加算回路ＳＵＭ１で加算され、双方向インバータＩＮＶ１への入力信号として加算回路ＳＵＭ１から出力される。
【００３１】
双方向インバータＩＮＶ１の直流側端子ＤＴ１、ＤＴ２に接続されたコンデンサＣ１は、所定の直流電圧を保持するためのものである。また、コンデンサＣ１は、双方向インバータＩＮＶ１が電源ラインに流すインバータ電流Ｉ２の供給源である。コンデンサＣ１では、インバータ電流Ｉ２の流れる方向に応じた充電動作と放電動作とが交互に行われる。すなわち、インバータ電流Ｉ２が図１に示す向きの場合（商用電流Ｉ１に対してインバータ電流Ｉ２を供給するように動作する場合）には、コンデンサＣ１は放電動作を行う。インバータ電流Ｉ２が図１に示す向きと逆の場合（商用電流Ｉ１からインバータ電流Ｉ２を引き込むように動作する場合）には、コンデンサＣ１は充電動作を行う。
【００３２】
双方向インバータＩＮＶ１の交流側端子ＡＴ１、ＡＴ２には加算回路ＳＵＭ１から出力される出力信号に基づいた所定の電圧が発生し、交流側端子ＡＴ１から所定のインバータ電流Ｉ２が流れ、電源ラインに供給される。図１から明らかなように、商用電流Ｉ１、インバータ電流Ｉ２および負荷電流Ｉ３との間には、Ｉ３＝Ｉ１＋Ｉ２の関係がある。この式が意味するところは、商用電源と双方向インバータＩＮＶ１とが負荷に供給する電流を分配するということにある。ところで、負荷には、負荷自体に依存した多様な電流が流れる。例えば、負荷には高調波が重畳した電流や位相遅れ／進みの電流が流れるが、これらの高調波電流や位相遅れ／進み電流の補償をインバータ電流Ｉ２が受け持つことによって、商用電源に流れる商用電流Ｉ１の波形を改善することができる。この作用により、商用電源側の力率を改善したり利用効率を向上させることができるのである。なお、このインバータ電流Ｉ２が供給される動作については後述する。
【００３３】
電流トランスＣＴ２は、双方向インバータＩＮＶ１が供給するインバータ電流Ｉ２の電流を検出する。この検出電流は、ダイオードＤ１を通じてコンデンサＣ２に充電される。コンデンサＣ２に充電された電圧は、可変利得電圧制御アンプＡＧＣ１の制御信号として用いられる。この制御信号は、インバータ電流Ｉ２の電流垂下用制御信号として、すなわち、インバータ電流Ｉ２が双方向インバータＩＮＶ１が供給できる許容能力を超えた場合にインバータ電流Ｉ２を急激に遮断（電源ラインに供給しない）するためのものである。したがって、コンデンサＣ２に充電された電圧が所定の電圧値を越えた場合には、可変利得電圧制御アンプＡＧＣ１の利得が下げられ、加算回路ＳＵＭ１への供給信号は小さくなる。なお、コンデンサＣ２に充電された電圧は、コンデンサＣ２の容量値や、図示しない抵抗、可変利得電圧制御アンプＡＧＣ１の入力インピーダンスなどによって決まる時定数に基づき、所定の周期ごと（例えば、商用電源の１周期ごと）に放電される。
【００３４】
一方、コンデンサＣ１に充電された電圧は、可変利得電圧制御アンプＡＧＣ２の制御信号として用いられる。この制御信号は、コンデンサＣ１に充電されている充電量の制御のために可変利得電圧制御アンプＡＧＣ２に供給されるものである。後述するインバータ電流Ｉ２の動作説明で明らかにするが、加算回路ＳＵＭ１からの出力が負の場合にはコンデンサＣ１が充電され、逆に、加算回路ＳＵＭ１からの出力が正の場合には、コンデンサＣ１から放電電流が流れる。したがって、コンデンサＣ１の電圧が大きいときには、可変利得電圧制御アンプＡＧＣ２の利得が下がるように制御され、逆に、コンデンサＣ１の電圧が小さいときには、可変利得電圧制御アンプＡＧＣ２の利得が上がるように制御される。また、可変利得電圧制御アンプＡＧＣ１の利得がコンデンサＣ２の電圧に基づいて急激に制御されるのに対し、可変利得電圧制御アンプＡＧＣ２の利得は、コンデンサＣ１の端子電圧に応じて連続的に制御される。
【００３５】
図２（ａ）はアクティブフィルタ装置１０の主要部の電圧信号または電流信号の波形を示す図であり、（ｂ）は双方向インバータＩＮＶ１への入力信号の波形を示す図である。同図（ａ）において、細い実線で示した部分、すなわち信号Ｋ１は、電圧トランスＰＴによって検出された商用電源の電圧信号である。また、太い実線で示した部分、すなわち信号Ｋ２は、電流トランスＣＴ１で検出された電流信号である。また、この電流信号である信号Ｋ２のうち、信号Ｋ３の部分は、負荷に生じた高調波電流によるものである。一方、破線で示した部分、すなわち信号Ｋ４は、反転回路ＰＲ１によって反転された反転波形である。
【００３６】
信号Ｋ２が可変利得電圧制御アンプＡＧＣ１に入力され、信号Ｋ４が可変利得電圧制御アンプＡＧＣ２に入力され、可変利得電圧制御アンプＡＧＣ１および可変利得電圧制御アンプＡＧＣ２がそれぞれ所定の利得に設定されると、加算回路ＳＵＭ１から同図（ｂ）に示す信号が出力される。このとき、双方向インバータＩＮＶ１の通常の機能によって、この信号が正のときは、同図（ｂ）に示す電流に比例したインバータ電流Ｉ２が双方向インバータＩＮＶ１から電源ラインに向かって供給される。逆に、この信号が負のときは、同図（ｂ）に示す電流に比例したインバータ電流Ｉ２が電源ラインから双方向インバータＩＮＶ１側に引き抜かれる。同図（ｂ）を用いて説明すると、網掛けのＬ１の部分では電流が引き抜かれ、網掛けのＬ２の部分では電流が供給される。これらの動作に連動して、コンデンサＣ１は、充電または放電の動作をそれぞれ行う。すなわち、Ｌ１の部分では、電源ラインから引き抜かれたインバータ電流Ｉ２によってコンデンサＣ１が充電され、Ｌ２の部分では、コンデンサＣ２から放電される電流により、電源ラインに向かうインバータ電流Ｉ２が供給される。
【００３７】
図３は、負荷に高調波を含んだ負荷電流が流れた場合に双方向インバータＩＮＶ１の補償電流によって商用電流が改善される様子を示す説明図であり、（ａ）は電源電圧（Ｖｉｎ）の波形を示す図であり、（ｂ）は（ａ）の電源電圧の反転信号の波形を示す図であり、（ｃ）は高調波を含んだ負荷電流の波形を示す図であり、（ｄ）は双方向インバータＩＮＶ１から抽出された補償電流の波形を示す図であり、（ｅ）は最終的な商用電流の波形を示す図である。
【００３８】
電圧トランスＰＴは、図３（ａ）に示す信号を検出し、反転回路ＰＲ１は、同図（ｂ）に示す信号を生成する。一方、電流トランスＣＴ１は、同図（ｃ）に示す信号を検出する。この検出信号は、高調波を含んだ負荷電流Ｉ３が商用電源側を流れた瞬間の商用電流Ｉ１を検出したものである。これらの同図（ｂ）および同図（ｃ）に示す信号が、可変利得電圧制御アンプＡＧＣ２および可変利得電圧制御アンプＡＧＣ１にそれぞれ入力され、可変利得電圧制御アンプＡＧＣ１および可変利得電圧制御アンプＡＧＣ２のそれぞれの利得が適正に制御されることで、上述した動作に従って、双方向インバータＩＮＶ１から同図（ｄ）に示す補償電流（インバータ電流Ｉ２）が電源ラインに供給される。このように、高調波電流を含んだ負荷電流Ｉ３が負荷に流れ、この高調波電流が商用電源側に流れたとき、商用電源側の商用電流Ｉ１の変化が検出され、この変化成分がインバータ電流Ｉ２によって補償される。その結果、商用電流Ｉ１は、同図（ｅ）に示すような正弦波形の電流が流れるようになる。
【００３９】
図４は、負荷に位相が遅れた位相遅れ電流が流れた場合に双方向インバータＩＮＶ１の補償電流によって位相遅れが改善される様子を示す説明図であり、（ａ）は電源電圧（Ｖｉｎ）の波形を示す図であり、（ｂ）は（ａ）の電源電圧の反転信号の波形を示す図であり、（ｃ）は遅れ電流の波形を示す図であり、（ｄ）は双方向インバータＩＮＶ１から抽出された補償電流の波形を示す図であり、（ｅ）は最終的な商用電流の波形を示す図である。
【００４０】
この場合においても、商用電源側に高調波電流が流れたときと全く同じ動作が行われ、双方向インバータＩＮＶ１の補償電流によって、商用電源側の波形が改善される。この波形改善は、双方向インバータＩＮＶ１の補償電流によって行われるので、負荷に流れる電流がどのような波形の電流であっても構わない。例えば、負荷に流れる電流が、進み電流であっても、また、高調波電流と遅れ電流または進み電流が同時に発生する場合であっても、商用電流の波形を改善することができる。
【００４１】
このように、負荷に発生した高調波電流や遅れ／進み電流が商用電源側に流れるときに、商用電源側に流れたこれらの電流を検出し、これらの電流を双方向インバータＩＮＶ１が補償するように動作するので、商用電源側に流れる電流信号の高調波成分を除去するとともに、遅れ／進み電流を補償することができ、商用電流の波形を改善することができる。また、コンデンサＣ１は、充電または放電を交互に行うように動作するので、大容量のコンデンサを用いることなく回路を実現することができる。また、コンデンサＣ１およびコンデンサＣ２の電圧に基づいて、それぞれ、可変利得電圧制御アンプＡＧＣ２および可変利得電圧制御アンプＡＧＣ１の利得を制御するようにしているので、双方向インバータＩＮＶ１の能力に応じた適正なインバータ電流Ｉ２を電源ラインに供給することができる。
【００４２】
以上説明したように、この実施の形態によれば、商用電源に接続された負荷から発生する高調波電流を補償するための補償電流の送出／引込を行うインバータと、インバータの直流側に接続されて補償電流の供給源となる補償電流供給手段と、インバータを制御するための商用電流検出手段および商用電圧検出手段を備えた制御手段とが備えられ、商用電流検出手段が検出した商用電流検出信号と商用電圧検出手段が検出した商用電圧検出信号との合成信号に基づいてインバータを制御するようにしているので、負荷に流れる電流によって商用電源側にどのような波形の電流が流れたとしても、商用電流の波形を改善することができるという効果を奏する。
【００４３】
また、この実施の形態によれば、制御手段は、インバータの直流側に接続された補償電流供給手段の端子電圧の変化に基づいて補償電流供給手段の充電／放電を制御するようにしているので、補償電流供給手段の供給能力に応じた補償電流の制御が実現できるという効果を奏する。
【００４４】
また、この実施の形態によれば、商用電流検出信号を増幅する第１の増幅器と、商用電圧検出信号を増幅する第２の増幅器とを備えた制御手段は、電流供給手段の端子電圧に基づいた第２の増幅器の利得を制御することにより、電流供給手段の充電量の制御を行うとともに、補償電流に基づいた第１の増幅器の利得制御により、インバータが行う補償電流の送出／引込の制御を行うようにしているので、波形解析等を行う必要がなく、応答速度に優れるとともに、装置が簡単かつ安価に構成できるという効果を奏する。
【００４５】
なお、ここでいうところの制御手段は、電圧トランスＰＴ、電流トランスＣＴ１、ＣＴ２、可変利得アンプＡＧＣ１、ＡＧＣ２、反転回路ＰＲ１、加算回路ＳＵＭ１、コンデンサＣ１、ダイオードＤ１により実現される。
【００４６】
また、ここでいうところの、商用電流検出手段は電流トランスＣＴ１に対応する。同様に、商用電圧検出手段は電圧トランスＰＴに対応し、補償電流供給手段はコンデンサＣ１に対応し、第１の増幅器は可変利得アンプＡＧＣ２に対応し、第２の増幅器は可変利得アンプＡＧＣ１に対応する。
【００４７】
【発明の効果】
以上説明したように、この発明によれば、インバータを制御するための商用電流検出手段および商用電圧検出手段を備えた制御手段とが備えられ、商用電流検出手段が検出した商用電流検出信号と商用電圧検出手段が検出した商用電圧検出信号との合成信号に基づいてインバータを制御するようにしているので、負荷に流れる電流によって商用電源側にどのような波形の電流が流れたとしても、商用電流の波形を改善することができるという効果を奏する。
【００４８】
また、この発明によれば、商用電流検出信号を増幅する第１の増幅器と、商用電圧検出信号を増幅する第２の増幅器とを備えた制御手段によって、電流供給手段の端子電圧に基づいた第２の増幅器の利得制御によって電流供給手段の充電量が制御され、また、補償電流に基づいた第１の増幅器の利得制御によってインバータが行う補償電流の送出／引込の制御が行われるので、商用電流や負荷電流の波形解析等を行う必要がなく、応答速度に優れるとともに、装置を簡単かつ安価に構成できるという効果を奏する。
【図面の簡単な説明】
【図１】この発明の実施の形態にかかる回路構成を示す図である。
【図２】（ａ）はアクティブフィルタ装置の主要部の電圧信号または電流信号の波形を示す図であり、（ｂ）は双方向インバータへの入力信号の波形を示す図である。
【図３】（ａ）は電源電圧の波形を示す図であり、（ｂ）は（ａ）の電源電圧の反転信号の波形を示す図であり、（ｃ）は高調波を含んだ負荷電流の波形を示す図であり、（ｄ）は双方向インバータから抽出された補償電流の波形を示す図であり、（ｅ）は最終的な商用電流の波形を示す図である。
【図４】（ａ）は電源電圧の波形を示す図であり、（ｂ）は（ａ）の電源電圧の反転信号の波形を示す図であり、（ｃ）は遅れ電流の波形を示す図であり、（ｄ）は双方向インバータから抽出された補償電流の波形を示す図であり、（ｅ）は最終的な商用電流の波形を示す図である。
【符号の説明】
１０アクティブフィルタ装置
ＡＧＣ１，ＡＧＣ２可変利得アンプ
ＡＴ１，ＡＴ２交流側端子
Ｃ１，Ｃ２コンデンサ
ＣＴ１，ＣＴ２電流トランス
Ｄ１ダイオード
ＤＴ１，ＤＴ２直流側端子
Ｉ１商用電流
Ｉ２インバータ電流
Ｉ３負荷電流
ＩＮＶ１双方向インバータ
Ｋ１，Ｋ２，Ｋ３，Ｋ４信号
ＰＲ１反転回路
ＰＴ電圧トランス
ＳＵＭ１加算回路
Ｖｉｎ電源電圧[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an active filter device that is inserted between a commercial power source and a load and performs current compensation, power factor improvement, and the like. In particular, the active filter device has a simple configuration and excellent response speed. The present invention relates to a filter device.
[0002]
[Prior art]
In recent home appliances such as a personal computer, a refrigerator, an air conditioner, and a lighting fixture, an inverter power supply is incorporated therein. Since the device incorporating this inverter power supply does not require switching of 50 Hz / 60 Hz, or has features such as quietness and power saving, it is expected that the use will be further promoted in the future. On the other hand, a device in which this inverter power supply is incorporated is also regarded as a problem that the power factor of the load is deteriorated due to the harmonic current flowing in the load, and the power use efficiency is lowered.
[0003]
As a conventional technique for solving these problems, for example, there is an active filter device described in Patent Document 1. The active filter device described in this document includes a compensation capability determination unit, a power factor correction compensation current control circuit, a reactive current compensation current control circuit, a compensation current control circuit, and the like, and the compensation capability determination unit is provided on the DC side of the inverter. Based on the voltage of the connected DC power supply, the surplus compensation capability of the compensation current that can be generated by the inverter is judged, and the power factor improvement compensation current control circuit is a force that matches the surplus compensation capability judged by the compensation capability judgment unit. On the other hand, the reactive current compensation current control circuit calculates the reactive current compensation current commensurate with the surplus compensation capability, and the compensation current control circuit calculates the harmonic compensation current and the power factor correction compensation current or Compensation of the harmonic current and power factor improvement compensation are performed by calculating a compensation current based on the harmonic compensation current and the reactive current compensation current and issuing a control command to the inverter.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 8-140267 (page 3-5, FIG. 1)
[0005]
[Problems to be solved by the invention]
By the way, in the above-described conventional active filter device, a circuit for detecting the fundamental wave current flowing in the power supply system, a circuit for detecting the harmonic current, and a circuit for detecting the driving power factor from the phase signal of the power supply voltage and the fundamental wave current. Since a wide variety of circuits such as a circuit for generating a compensation current, a phase inversion circuit, a phase shift circuit, an adder, and a multiplier are used, the device configuration is complicated, and thus the device is expensive. Had the disadvantages. Further, since waveform analysis of the signal waveform is indispensable for generating the compensation current, there is a problem that the response speed is slow.
[0006]
The present invention has been made in view of the above, and an object of the present invention is to obtain an active filter device that has a simple device configuration, does not particularly require means such as waveform analysis, and has excellent response speed.
[0007]
[Means for Solving the Problems]
  In order to solve the above-described problems and achieve the object, an active filter device according to the present invention is an inverter that sends / leads compensation current for compensating harmonic current generated from a load connected to a commercial power source. When,TheIn an active filter device comprising compensation current supply means connected to the DC side of an inverter and serving as a supply source of the compensation current, and control means for controlling the inverter, the control means flows to the commercial power source Commercial current detection means for detecting current components; commercial voltage detection means for detecting voltage components of the commercial power supply;A current detection signal amplifier that amplifies the commercial current detection signal detected by the commercial current detection means, and a combined signal of the output signal of the current detection signal amplifier and the commercial voltage detection signal detected by the commercial voltage detection means The inverter is controlled based on the control signal, and the compensation current sending / pulling control performed by the inverter is performed by gain control of the current detection signal amplifier based on the compensation current.
[0008]
  According to this invention,A commercial current detection signal detected by the commercial current detection means is amplified in a control means having a commercial current detection means for detecting a current component flowing in the commercial power supply and a commercial voltage detection means for detecting a voltage component of the commercial power supply. A current detection signal amplifier is provided, the inverter is controlled based on a composite signal of the output signal of the current detection signal amplifier and the commercial voltage detection signal detected by the commercial voltage detection means, and the compensation current sending / pulling control performed by the inverter is controlled. The gain control of the current detection signal amplifier based on the compensation current is performed.
[0013]
  An inverter for sending / withdrawing a compensation current for compensating for a harmonic current generated from a load connected to a commercial power source, and a compensation current supply means connected to the DC side of the inverter and serving as the supply source of the compensation current And a control means for controlling the inverter, wherein the control means detects a commercial current detection means for detecting a current component flowing in the commercial power supply, and detects a voltage component of the commercial power supply A commercial voltage detection means; and a voltage detection signal amplifier that amplifies the commercial voltage detection signal detected by the commercial voltage detection means, and the commercial current detection detected by the output signal of the voltage detection signal amplifier and the commercial current detection means The inverter is controlled based on a combined signal with the signal, and the charge amount of the compensation current supply means is controlled by the terminal voltage of the compensation current supply means. Characterized in that it is performed by the gain control of the voltage detection signal amplifier based.
[0014]
  According to this invention,The control means having the commercial current detection means for detecting the current component flowing in the commercial power supply and the commercial voltage detection means for detecting the voltage component of the commercial power supply amplifies the commercial voltage detection signal detected by the commercial voltage detection means. A voltage detection signal amplifier is provided, the inverter is controlled based on a combined signal of the output signal of the voltage detection signal amplifier and the commercial current detection signal detected by the commercial current detection means, and the charge amount control of the compensation current supply means is controlled, This is done by gain control of the voltage detection signal amplifier based on the terminal voltage of the compensation current supply means.
[0015]
  An inverter for sending / withdrawing a compensation current for compensating for a harmonic current generated from a load connected to a commercial power source, and a compensation current supply means connected to the DC side of the inverter and serving as the supply source of the compensation current And a control means for controlling the inverter, wherein the control means detects a commercial current detection means for detecting a current component flowing in the commercial power supply, and detects a voltage component of the commercial power supply A commercial voltage detection unit; a current detection signal amplifier that amplifies the commercial current detection signal detected by the commercial current detection unit; and a voltage detection signal amplifier that amplifies the commercial voltage detection signal detected by the commercial voltage detection unit. The inverter is controlled based on a combined signal of the output signal of the current detection signal amplifier and the output signal of the voltage detection signal amplifier; The compensation current sending / withdrawing control performed by the inverter is performed by gain control of the current detection signal amplifier based on the compensation current, and the charge amount of the compensation current supply means is controlled by a terminal of the compensation current supply means. It is performed by gain control of the voltage detection signal amplifier based on voltage.
[0016]
  According to this invention,A commercial current detection signal detected by the commercial current detection means is amplified in a control means having a commercial current detection means for detecting a current component flowing in the commercial power supply and a commercial voltage detection means for detecting a voltage component of the commercial power supply. A current detection signal amplifier; and a voltage detection signal amplifier that amplifies the commercial voltage detection signal detected by the commercial voltage detection means, and is based on a combined signal of the output signal of the current detection signal amplifier and the output signal of the voltage detection signal amplifier The inverter is controlled, and the compensation current sending / withdrawing control performed by the inverter is performed by the gain control of the current detection signal amplifier based on the compensation current, and the charge amount control of the compensation current supply means is controlled by the compensation current supply means. This is performed by controlling the gain of the voltage detection signal amplifier based on the terminal voltage.
[0017]
  An inverter for sending / withdrawing a compensation current for compensating for a phase lag / lead current generated from a load connected to a commercial power supply, and a compensation current connected to the DC side of the inverter and serving as a supply source of the compensation current In an active filter device comprising a supply means and a control means for controlling the inverter, the control means comprises a commercial current detection means for detecting a current component flowing through the commercial power supply, and a voltage component of the commercial power supply. A commercial voltage detecting means for detecting, and a current detection signal amplifier for amplifying the commercial current detection signal detected by the commercial current detecting means, and the commercial signal detected by the output signal of the current detection signal amplifier and the commercial voltage detecting means The inverter is controlled based on a combined signal with the voltage detection signal, and the compensation current sending / withdrawing control performed by the inverter is the compensation signal. Characterized in that it is performed by the gain control of the current detection signal amplifier based on flow.
[0018]
  According to this invention,A commercial current detection signal detected by the commercial current detection means is amplified in a control means having a commercial current detection means for detecting a current component flowing in the commercial power supply and a commercial voltage detection means for detecting a voltage component of the commercial power supply. A current detection signal amplifier is provided, the inverter is controlled based on a composite signal of the output signal of the current detection signal amplifier and the commercial voltage detection signal detected by the commercial voltage detection means, and the compensation current sending / pulling control performed by the inverter is controlled. The gain control of the current detection signal amplifier based on the compensation current is performed.
[0019]
  An inverter for sending / withdrawing a compensation current for compensating for a phase lag / lead current generated from a load connected to a commercial power supply, and a compensation current connected to the DC side of the inverter and serving as a supply source of the compensation current In an active filter device comprising a supply means and a control means for controlling the inverter, the control means comprises a commercial current detection means for detecting a current component flowing through the commercial power supply, and a voltage component of the commercial power supply. A commercial voltage detection means for detecting; and a voltage detection signal amplifier for amplifying a commercial voltage detection signal detected by the commercial voltage detection means, wherein the commercial signal detected by the output signal of the voltage detection signal amplifier and the commercial current detection means The inverter is controlled based on a combined signal with a current detection signal, and the charge amount of the compensation current supply means is controlled by the compensation current supply means. Characterized in that it is performed by the gain control of the voltage detection signal amplifier based on the child voltage.
[0020]
  According to this invention,The control means having the commercial current detection means for detecting the current component flowing in the commercial power supply and the commercial voltage detection means for detecting the voltage component of the commercial power supply amplifies the commercial voltage detection signal detected by the commercial voltage detection means. A voltage detection signal amplifier is provided, the inverter is controlled based on a combined signal of the output signal of the voltage detection signal amplifier and the commercial current detection signal detected by the commercial current detection means, and the charge amount control of the compensation current supply means is controlled, This is done by gain control of the voltage detection signal amplifier based on the terminal voltage of the compensation current supply means.
[0021]
  An inverter for sending / withdrawing a compensation current for compensating for a phase lag / lead current generated from a load connected to a commercial power supply, and a compensation current connected to the DC side of the inverter and serving as a supply source of the compensation current In an active filter device comprising a supply means and a control means for controlling the inverter, the control means comprises a commercial current detection means for detecting a current component flowing through the commercial power supply, and a voltage component of the commercial power supply. A commercial voltage detection means for detecting, a current detection signal amplifier for amplifying the commercial current detection signal detected by the commercial current detection means, a voltage detection signal amplifier for amplifying the commercial voltage detection signal detected by the commercial voltage detection means, And the inverter is controlled based on a combined signal of the output signal of the current detection signal amplifier and the output signal of the voltage detection signal amplifier. The compensation current sending / withdrawing control performed by the inverter is performed by gain control of the current detection signal amplifier based on the compensation current, and the charge amount of the compensation current supply means is controlled by the compensation current supply. It is performed by gain control of the voltage detection signal amplifier based on the terminal voltage of the means.
[0022]
  According to this invention,A commercial current detection signal detected by the commercial current detection means is amplified in a control means having a commercial current detection means for detecting a current component flowing in the commercial power supply and a commercial voltage detection means for detecting a voltage component of the commercial power supply. A current detection signal amplifier; and a voltage detection signal amplifier that amplifies the commercial voltage detection signal detected by the commercial voltage detection means, and is based on a combined signal of the output signal of the current detection signal amplifier and the output signal of the voltage detection signal amplifier The inverter is controlled, and the compensation current sending / withdrawing control performed by the inverter is performed by the gain control of the current detection signal amplifier based on the compensation current, and the charge amount control of the compensation current supply means is controlled by the compensation current supply means. This is performed by controlling the gain of the voltage detection signal amplifier based on the terminal voltage.
[0023]
  The compensation current supply means is constituted by a capacitor.
[0024]
  According to the present invention, an active filter device can be simply configured using a capacitor.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of an active filter device according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.
[0026]
FIG. 1 is a diagram showing a circuit configuration according to an embodiment of the present invention. In the figure, an active filter device 10 having an input terminal and an output terminal includes a voltage transformer PT, current transformers CT1 and CT2, variable gain voltage control amplifiers AGC1 and AGC2, an inverter circuit PR1, an adder circuit SUM1, and a bidirectional inverter. INV1, a diode D1, and capacitors C1 and C2 are provided. A commercial power supply is connected to the input terminal of the active filter device 10, and a load is connected to the output terminal.
[0027]
Next, a circuit configuration of the active filter device 10 according to the embodiment will be described. In FIG. 1, the voltage transformer PT includes a primary winding and a secondary winding. The primary winding of the voltage transformer PT is connected to a power supply line in the active filter device 10. The secondary winding is connected to the inverting circuit PR1. The current transformer CT1 is connected across the power supply line (feed line) in order to detect a current flowing through the power supply line on one end of the power supply line in the active filter device 10 without being inserted into the power supply line. The adder circuit SUM1 is connected to the variable gain voltage control amplifier AGC1 connected to the current transformer CT1 on the input side and the variable gain voltage control amplifier AGC2 connected to the inverting circuit PR1, and connected to the bidirectional inverter INV1 on the output side. .
[0028]
The bidirectional inverter INV1 includes a pair of DC side terminals DT1 and DT2 and a pair of AC side terminals AT1 and AT2. The AC side terminal AT1 of the bidirectional inverter INV1 is connected to one power supply line, and the AC side terminal AT2 is connected to the other power supply line. The DC-side terminal DT1 of the bidirectional inverter INV1 is connected to one end of the capacitor C1, and the DC-side terminal DT2 is connected to the other end of the capacitor C1 (a ground end that is also grounded to the circuit ground at the same time). One end of the capacitor C1 connected to the DC side terminal DT1 of the bidirectional inverter INV1 is also connected to the variable gain voltage control amplifier AGC2. A current transformer CT2 connected to the anode of the diode D1 is connected across the line on the line connecting the DC side terminal DT1 of the bidirectional inverter INV1 and one power supply line. The cathode of the diode D1 is connected to the variable gain voltage control amplifier AGC1, and is also connected to one end of the capacitor C2. The other end of the capacitor C2 is installed on the circuit ground in the same manner as the capacitor C1.
[0029]
Next, the operation of the active filter device 10 shown in FIG. 1 will be described. I1, I2, and I3 shown in the figure represent the commercial current flowing to the commercial power supply side, the inverter current output from the bidirectional inverter INV1, and the load current flowing to the load side, respectively. Incidentally, as is clear from the figure, only the current transformer CT1 exists on the power supply line for supplying the commercial power supply between the commercial power supply and the load. The current transformer CT1 detects the current flowing through the load without being inserted into the power supply line, and does not affect the operation between the commercial power supply and the load. Therefore, when this active filter device 10 does not act on the commercial power supply or the load, that is, when the inverter current I2 does not flow, the commercial current becomes the load current as it is.
[0030]
In FIG. 1, a voltage transformer PT detects a power supply voltage Vin supplied by a commercial power supply, and a current transformer CT1 detects a commercial current I1 flowing through the power supply line. The voltage signal detected by the voltage transformer PT is inverted by the inverter circuit PR1 and input to the variable gain voltage control amplifier AGC2. On the other hand, the current signal detected by the current transformer CT1 is directly input to the variable gain voltage control amplifier AGC1. These signals are amplified by the variable gain voltage control amplifiers AGC1 and AGC2, added by the adder circuit SUM1, and output from the adder circuit SUM1 as an input signal to the bidirectional inverter INV1.
[0031]
The capacitor C1 connected to the DC side terminals DT1 and DT2 of the bidirectional inverter INV1 is for holding a predetermined DC voltage. The capacitor C1 is a supply source of the inverter current I2 that the bidirectional inverter INV1 passes through the power supply line. In the capacitor C1, a charging operation and a discharging operation corresponding to the direction in which the inverter current I2 flows are alternately performed. That is, when the inverter current I2 is in the direction shown in FIG. 1 (when the inverter current I2 operates so as to supply the inverter current I2 with respect to the commercial current I1), the capacitor C1 performs a discharging operation. When the inverter current I2 is opposite to the direction shown in FIG. 1 (when operating so as to draw the inverter current I2 from the commercial current I1), the capacitor C1 performs a charging operation.
[0032]
A predetermined voltage based on the output signal output from the adder circuit SUM1 is generated at the AC side terminals AT1 and AT2 of the bidirectional inverter INV1, and a predetermined inverter current I2 flows from the AC side terminal AT1 and is supplied to the power supply line. The As is apparent from FIG. 1, there is a relationship of I3 = I1 + I2 among the commercial current I1, the inverter current I2, and the load current I3. This equation means that the commercial power supply and the bidirectional inverter INV1 distribute the current supplied to the load. By the way, various currents depend on the load itself. For example, a current in which harmonics are superimposed or a phase lag / lead current flows in the load, and the inverter current I2 is responsible for compensation of these harmonic currents or phase lag / lead currents, so that the commercial current flowing in the commercial power source The waveform of I1 can be improved. With this action, the power factor on the commercial power source side can be improved and the utilization efficiency can be improved. The operation for supplying the inverter current I2 will be described later.
[0033]
The current transformer CT2 detects the current of the inverter current I2 supplied from the bidirectional inverter INV1. This detection current is charged to the capacitor C2 through the diode D1. The voltage charged in the capacitor C2 is used as a control signal for the variable gain voltage control amplifier AGC1. This control signal is a control signal for drooping the inverter current I2, that is, when the inverter current I2 exceeds the allowable capacity that the bidirectional inverter INV1 can supply, the inverter current I2 is suddenly cut off (not supplied to the power supply line). Is to do. Therefore, when the voltage charged in the capacitor C2 exceeds a predetermined voltage value, the gain of the variable gain voltage control amplifier AGC1 is lowered, and the supply signal to the adding circuit SUM1 becomes small. Note that the voltage charged in the capacitor C2 is based on a time constant determined by a capacitance value of the capacitor C2, a resistor (not shown), an input impedance of the variable gain voltage control amplifier AGC1, and the like (for example, 1 of the commercial power supply). Discharged every cycle).
[0034]
On the other hand, the voltage charged in the capacitor C1 is used as a control signal for the variable gain voltage control amplifier AGC2. This control signal is supplied to the variable gain voltage control amplifier AGC2 in order to control the amount of charge charged in the capacitor C1. As will be apparent from the description of the operation of the inverter current I2 described later, when the output from the adder circuit SUM1 is negative, the capacitor C1 is charged. Conversely, when the output from the adder circuit SUM1 is positive, the capacitor C1 is charged. Discharge current flows from. Therefore, when the voltage of the capacitor C1 is large, the gain of the variable gain voltage control amplifier AGC2 is controlled to decrease. Conversely, when the voltage of the capacitor C1 is small, the gain of the variable gain voltage control amplifier AGC2 is controlled to increase. The In addition, the gain of the variable gain voltage control amplifier AGC1 is rapidly controlled based on the voltage of the capacitor C2, whereas the gain of the variable gain voltage control amplifier AGC2 is continuously controlled according to the terminal voltage of the capacitor C1. The
[0035]
2A is a diagram showing the waveform of the voltage signal or current signal of the main part of the active filter device 10, and FIG. 2B is a diagram showing the waveform of the input signal to the bidirectional inverter INV1. In FIG. 5A, a portion indicated by a thin solid line, that is, a signal K1 is a voltage signal of a commercial power source detected by the voltage transformer PT. Further, a portion indicated by a thick solid line, that is, a signal K2 is a current signal detected by the current transformer CT1. Further, in the signal K2, which is the current signal, the portion of the signal K3 is due to the harmonic current generated in the load. On the other hand, a portion indicated by a broken line, that is, the signal K4 is an inverted waveform inverted by the inverter circuit PR1.
[0036]
When the signal K2 is input to the variable gain voltage control amplifier AGC1, the signal K4 is input to the variable gain voltage control amplifier AGC2, and the variable gain voltage control amplifier AGC1 and the variable gain voltage control amplifier AGC2 are set to predetermined gains, The adder circuit SUM1 outputs a signal shown in FIG. At this time, when this signal is positive due to the normal function of the bidirectional inverter INV1, an inverter current I2 proportional to the current shown in FIG. 5B is supplied from the bidirectional inverter INV1 toward the power supply line. Conversely, when this signal is negative, an inverter current I2 proportional to the current shown in FIG. 5B is drawn from the power supply line to the bidirectional inverter INV1 side. Explaining with reference to FIG. 2B, the current is drawn in the shaded portion L1, and the current is supplied in the shaded portion L2. In conjunction with these operations, the capacitor C1 performs a charging or discharging operation. That is, in the portion L1, the capacitor C1 is charged by the inverter current I2 drawn from the power supply line, and in the portion L2, the inverter current I2 toward the power supply line is supplied by the current discharged from the capacitor C2.
[0037]
FIG. 3 is an explanatory diagram showing how the commercial current is improved by the compensation current of the bidirectional inverter INV1 when a load current containing harmonics flows in the load. FIG. 3A is a diagram illustrating the power supply voltage (Vin). It is a figure which shows a waveform, (b) is a figure which shows the waveform of the inversion signal of the power supply voltage of (a), (c) is a figure which shows the waveform of the load current containing a harmonic, (d) FIG. 6 is a diagram showing a waveform of a compensation current extracted from the bidirectional inverter INV1, and FIG. 5E is a diagram showing a final waveform of a commercial current.
[0038]
The voltage transformer PT detects the signal shown in FIG. 3A, and the inverting circuit PR1 generates the signal shown in FIG. On the other hand, the current transformer CT1 detects the signal shown in FIG. This detection signal is obtained by detecting the commercial current I1 at the moment when the load current I3 including harmonics flows through the commercial power supply side. These signals shown in FIG. 5B and FIG. 6C are input to the variable gain voltage control amplifier AGC2 and the variable gain voltage control amplifier AGC1, respectively, and the variable gain voltage control amplifier AGC1 and the variable gain voltage control amplifier AGC2 By appropriately controlling the respective gains, the compensation current (inverter current I2) shown in FIG. 4D is supplied from the bidirectional inverter INV1 to the power supply line in accordance with the above-described operation. As described above, when the load current I3 including the harmonic current flows to the load and this harmonic current flows to the commercial power supply side, a change in the commercial current I1 on the commercial power supply side is detected, and this change component becomes the inverter current. Compensated by I2. As a result, a sine waveform current as shown in FIG.
[0039]
FIG. 4 is an explanatory diagram showing how the phase lag is improved by the compensation current of the bidirectional inverter INV1 when a phase lag current flowing in the load flows through the load. FIG. 4A is a diagram illustrating the power supply voltage (Vin). It is a figure which shows a waveform, (b) is a figure which shows the waveform of the inversion signal of the power supply voltage of (a), (c) is a figure which shows the waveform of a delay current, (d) is a bidirectional | two-way inverter INV1. It is a figure which shows the waveform of the compensation current extracted from (e), and (e) is a figure which shows the waveform of the final commercial current.
[0040]
Even in this case, the same operation as when the harmonic current flows to the commercial power supply side is performed, and the waveform on the commercial power supply side is improved by the compensation current of the bidirectional inverter INV1. Since the waveform improvement is performed by the compensation current of the bidirectional inverter INV1, the current flowing through the load may be any waveform. For example, the waveform of the commercial current can be improved even when the current flowing through the load is a leading current, or when a harmonic current and a lagging current or a leading current are generated simultaneously.
[0041]
As described above, when the harmonic current or the lag / lead current generated in the load flows to the commercial power source side, these currents flowing to the commercial power source side are detected, and these currents are compensated by the bidirectional inverter INV1. Therefore, the harmonic component of the current signal flowing to the commercial power source side can be removed, the delay / lead current can be compensated, and the commercial current waveform can be improved. Further, since the capacitor C1 operates so as to alternately perform charging or discharging, a circuit can be realized without using a large-capacitance capacitor. Further, since the gains of the variable gain voltage control amplifier AGC2 and the variable gain voltage control amplifier AGC1 are controlled based on the voltages of the capacitor C1 and the capacitor C2, respectively, an appropriate value according to the capability of the bidirectional inverter INV1 is obtained. The inverter current I2 can be supplied to the power supply line.
[0042]
As described above, according to this embodiment, the inverter is connected to the inverter for sending / withdrawing the compensation current for compensating the harmonic current generated from the load connected to the commercial power source, and the DC side of the inverter. Compensation current supply means serving as a supply source of compensation current, and control means including commercial current detection means and commercial voltage detection means for controlling the inverter, and a commercial current detection signal detected by the commercial current detection means And the commercial voltage detection signal detected by the commercial voltage detection means, the inverter is controlled, so that no matter what waveform current flows to the commercial power source due to the current flowing through the load, There is an effect that the waveform of the commercial current can be improved.
[0043]
Further, according to this embodiment, the control means controls charging / discharging of the compensation current supply means based on a change in the terminal voltage of the compensation current supply means connected to the DC side of the inverter. The compensation current can be controlled according to the supply capability of the compensation current supply means.
[0044]
According to this embodiment, the control means including the first amplifier that amplifies the commercial current detection signal and the second amplifier that amplifies the commercial voltage detection signal is based on the terminal voltage of the current supply means. Further, the charge amount of the current supply means is controlled by controlling the gain of the second amplifier, and the compensation current is sent and drawn by the inverter by the gain control of the first amplifier based on the compensation current. Therefore, there is no need to perform waveform analysis or the like, and the response speed is excellent, and the apparatus can be configured easily and inexpensively.
[0045]
The control means mentioned here is realized by a voltage transformer PT, current transformers CT1 and CT2, variable gain amplifiers AGC1 and AGC2, an inverting circuit PR1, an adding circuit SUM1, a capacitor C1, and a diode D1.
[0046]
Further, the commercial current detecting means mentioned here corresponds to the current transformer CT1. Similarly, the commercial voltage detection means corresponds to the voltage transformer PT, the compensation current supply means corresponds to the capacitor C1, the first amplifier corresponds to the variable gain amplifier AGC2, and the second amplifier corresponds to the variable gain amplifier AGC1. To do.
[0047]
【The invention's effect】
As described above, according to the present invention, the commercial current detection means for controlling the inverter and the control means including the commercial voltage detection means are provided, and the commercial current detection signal detected by the commercial current detection means and the commercial current are detected. Since the inverter is controlled based on the combined signal with the commercial voltage detection signal detected by the voltage detection means, no matter what waveform current flows to the commercial power source due to the current flowing through the load, the commercial current There is an effect that the waveform can be improved.
[0048]
Further, according to the present invention, the control means including the first amplifier that amplifies the commercial current detection signal and the second amplifier that amplifies the commercial voltage detection signal, the first amplifier based on the terminal voltage of the current supply means. Since the charge amount of the current supply means is controlled by the gain control of the amplifier 2 and the compensation current is sent / drawn by the inverter by the gain control of the first amplifier based on the compensation current, the commercial current There is no need to perform waveform analysis of the load current or the like, and the response speed is excellent, and the apparatus can be configured easily and inexpensively.
[Brief description of the drawings]
FIG. 1 is a diagram showing a circuit configuration according to an embodiment of the present invention.
2A is a diagram showing a waveform of a voltage signal or a current signal of a main part of the active filter device, and FIG. 2B is a diagram showing a waveform of an input signal to a bidirectional inverter.
3A is a diagram illustrating a waveform of a power supply voltage, FIG. 3B is a diagram illustrating a waveform of an inverted signal of the power supply voltage of FIG. 3A, and FIG. 3C is a load current including harmonics; (D) is a figure which shows the waveform of the compensation current extracted from the bidirectional | two-way inverter, (e) is a figure which shows the waveform of the final commercial current.
4A is a diagram showing a waveform of a power supply voltage, FIG. 4B is a diagram showing a waveform of an inverted signal of the power supply voltage in FIG. 4A, and FIG. 4C is a diagram showing a waveform of a delayed current; (D) is a figure which shows the waveform of the compensation current extracted from the bidirectional | two-way inverter, (e) is a figure which shows the waveform of the final commercial current.
[Explanation of symbols]
10 Active filter device
AGC1, AGC2 variable gain amplifier
AT1, AT2 AC side terminal
C1, C2 capacitors
CT1, CT2 Current transformer
D1 diode
DT1, DT2 DC side terminal
I1 Commercial current
I2 Inverter current
I3 Load current
INV1 bidirectional inverter
K1, K2, K3, K4 signals
PR1 Inversion circuit
PT voltage transformer
SUM1 addition circuit
Vin power supply voltage

Claims

An inverter for performing sending / pull compensation current for compensating the harmonic current generated from a load connected to a commercial power source, is connected to the DC side of the inverter becomes a source of said compensation current compensating current supplying means And an active filter device comprising control means for controlling the inverter,
The control means includes
Commercial current detection means for detecting a current component flowing in the commercial power supply;
Commercial voltage detecting means for detecting a voltage component of the commercial power supply;
A current detection signal amplifier that amplifies the commercial current detection signal detected by the commercial current detection means ;
With
The inverter is controlled based on a combined signal of the output signal of the current detection signal amplifier and the commercial voltage detection signal detected by the commercial voltage detection means ,
The active filter device , wherein the compensation current sending / withdrawing control performed by the inverter is performed by gain control of the current detection signal amplifier based on the compensation current .

An inverter for sending / withdrawing a compensation current for compensating for a harmonic current generated from a load connected to a commercial power source, and a compensation current supply means connected to the DC side of the inverter and serving as the supply source of the compensation current And an active filter device comprising control means for controlling the inverter,
  The control means includes
  Commercial current detection means for detecting a current component flowing in the commercial power supply;
  Commercial voltage detecting means for detecting a voltage component of the commercial power supply;
  A voltage detection signal amplifier that amplifies the commercial voltage detection signal detected by the commercial voltage detection means;
  With
  The inverter is controlled based on a combined signal of the output signal of the voltage detection signal amplifier and the commercial current detection signal detected by the commercial current detection means,
  An active filter device characterized in that the charge amount of the compensation current supply means is controlled by gain control of the voltage detection signal amplifier based on the terminal voltage of the compensation current supply means.

An inverter for performing sending / pull compensation current for compensating the harmonic current generated from a load connected to a commercial power source, is connected to the DC side of the inverter becomes a source of said compensation current compensating current supplying means And an active filter device comprising control means for controlling the inverter,
The control means includes
Commercial current detection means for detecting a current component flowing in the commercial power supply;
Commercial voltage detecting means for detecting a voltage component of the commercial power supply;
A current detection signal amplifier that amplifies the commercial current detection signal detected by the commercial current detection means;
A voltage detection signal amplifier that amplifies the commercial voltage detection signal detected by the commercial voltage detection means;
With
The inverter is controlled based on a combined signal of the output signal of the current detection signal amplifier and the output signal of the voltage detection signal amplifier,
Sending / withdrawing the compensation current performed by the inverter is performed by gain control of the current detection signal amplifier based on the compensation current,
An active filter device characterized in that the charge amount of the compensation current supply means is controlled by gain control of the voltage detection signal amplifier based on the terminal voltage of the compensation current supply means.

An inverter for sending / withdrawing a compensation current for compensating a phase lag / lead current generated from a load connected to a commercial power source, and a compensation current connected to the DC side of the inverter and serving as a supply source of the compensation current In an active filter device comprising supply means and control means for controlling the inverter,
The control means includes
Commercial current detection means for detecting a current component flowing in the commercial power supply;
Commercial voltage detecting means for detecting a voltage component of the commercial power supply;
A current detection signal amplifier that amplifies the commercial current detection signal detected by the commercial current detection means;
With
The inverter is controlled based on a combined signal of the output signal of the current detection signal amplifier and the commercial voltage detection signal detected by the commercial voltage detection means,
The active filter device, wherein the compensation current sending / withdrawing control performed by the inverter is performed by gain control of the current detection signal amplifier based on the compensation current.

An inverter for sending / withdrawing a compensation current for compensating for a phase lag / lead current generated from a load connected to a commercial power supply, and a compensation current connected to the DC side of the inverter and serving as a supply source of the compensation current In an active filter device comprising supply means and control means for controlling the inverter,
  The control means includes
  Commercial current detection means for detecting a current component flowing in the commercial power supply;
  Commercial voltage detecting means for detecting a voltage component of the commercial power supply;
  A voltage detection signal amplifier that amplifies the commercial voltage detection signal detected by the commercial voltage detection means;
  With
  The inverter is controlled based on a combined signal of the output signal of the voltage detection signal amplifier and the commercial current detection signal detected by the commercial current detection means,
  An active filter device characterized in that the charge amount of the compensation current supply means is controlled by gain control of the voltage detection signal amplifier based on the terminal voltage of the compensation current supply means.

An inverter for sending / withdrawing a compensation current for compensating a phase lag / lead current generated from a load connected to a commercial power source, and a compensation current connected to the DC side of the inverter and serving as a supply source of the compensation current In an active filter device comprising supply means and control means for controlling the inverter,
The control means includes
Commercial current detection means for detecting a current component flowing in the commercial power supply;
Commercial voltage detecting means for detecting a voltage component of the commercial power supply;
A current detection signal amplifier that amplifies the commercial current detection signal detected by the commercial current detection means;
A voltage detection signal amplifier that amplifies the commercial voltage detection signal detected by the commercial voltage detection means;
With
The inverter is controlled based on a combined signal of the output signal of the current detection signal amplifier and the output signal of the voltage detection signal amplifier,
Sending / withdrawing the compensation current performed by the inverter is performed by gain control of the current detection signal amplifier based on the compensation current,
An active filter device characterized in that the charge amount of the compensation current supply means is controlled by gain control of the voltage detection signal amplifier based on the terminal voltage of the compensation current supply means.

The active filter device according to claim 1, wherein the compensation current supply unit includes a capacitor.