JP3632120B2

JP3632120B2 - Uninterruptible power system

Info

Publication number: JP3632120B2
Application number: JP19416499A
Authority: JP
Inventors: 幹也野原; 茂太上田; 秀恭梅津; 玲彦叶田
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 1999-07-08
Filing date: 1999-07-08
Publication date: 2005-03-23
Anticipated expiration: 2019-07-08
Also published as: JP2001025178A

Description

【発明の属する技術分野】
【０００１】
本発明は、無停電電源装置に係り、特に、負荷に安定した電力を供給するとともに、蓄電池を最適に充電する回路構成に関する。
【従来の技術】
【０００２】
第１交直変換器を出力端に並列接続し、第２交直変換器を入力端と出力端との間に直列接続した無停電電源装置が、IEEE TRANSACTIONS ON POWER ELECTRONICS,VOL.13,No.3,MAY 1998,"A Novel On-Line UPS with Universal Filtering Capabilities"に記載されている。
【０００３】
図１０は、従来の無停電電源装置の一例の系統構成を示すブロック図である。この無停電電源装置は、第１交直変換器１と第２交直変換器２とを備えている。第１交直変換器１の交流側は、フィルタ用リアクトル１４を介して、出力端に並列接続してあり、フィルタ用コンデンサ７も、出力端に並列接続してある。この出力端には、負荷１０が接続される。
【０００４】
外部交流電源９が接続されている入力端からは、スイッチ１３を介して、交流電力が導入される。第２交直変換器２の交流側は、巻数比１：ｎ２の変圧器５を介して、入力端と出力端との間に直列接続してある。
【０００５】
第１交直変換器１の直流側には、直流コンデンサ６を並列接続し、蓄電池放電防止用リアクトル１５を介して、蓄電池３を接続してある。
【０００６】
電流検出器１１９は、入力電流Ｉinを検出する。電流検出器１１３は、蓄電池電流Ｉbattを検出する。電流検出器１１０は、出力電流Ｉoutを検出する。電圧検出器１１４は、出力電圧Ｖoutを検出する。制御回路１２は、これらの電流検出値と電圧検出値とに基づき制御演算を実行し、第１，第２交直変換器１，２を制御する。
【０００７】
外部交流電源９が停電した場合は、スイッチ１３を開き、第１交直変換器１で蓄電池３の電力を交流に変換し、負荷１０に交流電力を供給する。
【０００８】
外部交流電源９が正常な通常状態では、制御回路１２は、出力電圧Ｖoutおよび出力電流Ｉoutから負荷１０の平均電力を演算する。第２交直変換器２は、演算された負荷１０への平均電力と蓄電池３への充電電力とを供給し、制御回路１２は、入力電流Ｉinが正弦波となるように、第２交直変換器２の電圧を制御する。制御回路１２は、また、出力電圧Ｖoutと入力電流Ｉin，出力電流Ｉoutとから、完全次元オブザーバにより、第１交直変換器１の入力電流を推定し、有限制定応答制御により、出力電圧Ｖoutを一定に保つように、第１交直変換器１の電圧を制御する。
【０００９】
このように、上記文献の技術を用いれば、入力電源９や負荷１０が急変しても入力電流Ｉinを正弦波に保ち、アクティブフィルタの機能により、負荷１０と蓄電池３とに安定した電力を供給できるとされている。
【発明が解決しようとする課題】
【００１０】
無停電電源装置は、コンピュータ機器に最も広く使用される。これらのコンピュータ機器は、５，７，９，１１次などの低次の高調波を多く含む。
【００１１】
前記従来の無停電電源装置においては、第２交直変換器２が負荷に供給する電力を平均値で計算し、入力電流Ｉinを正弦波に保てば、充電電流が高調波の分だけ減少するとしている。
【００１２】
充電電流が高調波に比べて充分大きければ、問題は無い。しかし、蓄電池３が満充電に近くなると、充電電流を小さくしなければならないので、直流部から負荷１０に高調波成分を含む電力を供給することになる。このとき、蓄電池３を放電させないためには、蓄電池放電防止用リアクトル１５を挿入し、蓄電池３の低次高調波に対するインピーダンスを直流コンデンサ６に対して充分大きくする必要がある。
【００１３】
図１１は、図１０に示した従来の無停電電源装置における電圧電流波形を示す図である。出力電圧Ｖoutと入力電流Ｉinとは、正弦波となるように制御されている。負荷１０は、コンピュータ機器を想定しているので、負荷電流Ｉoutは、低次の高調波を多く含む波形となる。リアクトル１５の働きで、充電電流Ｉbattは、ほぼ直流であるが、直流コンデンサ６の電流ＩCdcとしては、第１交直変換器１のスイッチングに伴う高次の高調波成分の他に、出力電流Ｉoutの低次の高調波成分が流れる。
【００１４】
そこで、直流コンデンサ６のリプル耐量を大きくする必要がある。蓄電池放電防止用リアクトル１５と大きなリプル耐量の直流コンデンサ６とが必要なことから、無停電電源装置の体積が大きくなる。また、制御演算が複雑となるために、高機能のマイクロコンピュータを搭載しなければならない。
【００１５】
本発明の目的は、直流コンデンサのリプル耐量を上げたり、蓄電池放電防止用リアクトルを設けたりせずに、第１交直変換器と第２交直変換器との間で電力を授受するとともに、蓄電池を安定に充電できる無停電電源装置を提供することである。
【課題を解決するための手段】
【００１６】
本発明は、上記目的を達成するために、入力端に接続した外部交流電源から交流電力を導入し、第１交直変換器の交流側を出力端に並列接続し、第２交直変換器の交流側を入力端と出力端との間に直列接続し、第１交直変換器および第２交直変換器の直流側に直流電力貯蔵手段および直流コンデンサを並列接続し、通常時は出力端に接続された負荷に交流電力を供給するとともに直流電力貯蔵手段を充電しておき、外部交流電源の停電時に第１交直変換器が直流電力貯蔵手段の直流電力を交流電力に変換し負荷に供給する無停電電源装置において、第１交直変換器の交流側電流を検出する手段と、第２交直変換器の直流側電流を検出する手段と、直流電力貯蔵手段の充電電流および直流電圧を検出する手段と、無停電電源装置の出力電圧を検出する手段と、第２交直変換器の直流側電流検出値の高次の高調波成分を除去する手段とを備え、外部交流電源からの入力電圧と第２交直変換器の交流側電圧との和が所定の出力電圧になるように第２交直変換器を制御する手段と、直流電圧の検出値に応じた充電電流の指令値を算出し、充電電流の指令値と充電電流の検出値との誤差成分と第２交直変換器の直流側電流検出値の高次の高調波を除去した値との和を出力電圧の検出値が正か負かにより正負を反転させ、第１交直変換器の交流側電流の指令値とし、第１交直変換器の交流側電流の検出値を指令値に追従させる手段とを備えた無停電電源装置を提案する。
【００１７】
本発明は、さらに、入力端に接続した外部交流電源から交流電力を導入し、第１交直変換器の交流側を出力端に並列接続し、第２交直変換器の交流側を入力端と出力端との間に直列接続し、第１交直変換器および第２交直変換器の直流側に直流電力貯蔵手段および直流コンデンサを並列接続し、通常時は出力端に接続された負荷に交流電力を供給するとともに直流電力貯蔵手段を充電しておき、外部交流電源の停電時に第１交直変換器が直流電力貯蔵手段の直流電力を交流電力に変換し負荷に供給する無停電電源装置において、第１交直変換器の直流側電流および交流側電流を検出する手段と、第２交直変換器の直流側電流を検出する手段と、直流電力貯蔵手段の直流電圧を検出する手段と、無停電電源装置の出力電圧を検出する手段と、第１交直変換器の直流側電流検出値および第２交直変換器の直流側電流検出値の高次の高調波成分をそれぞれ除去する手段とを備え、外部交流電源からの入力電圧と第２交直変換器の交流側電圧との和が所定の出力電圧となるように第２交直変換器を制御する手段と、直流電圧の検出値に応じた充電電流の指令値を算出し、充電電流の指令値および第２交直変換器の直流側電流検出値の高次の高調波を除去した値の和と第１交直変換器の直流側電流の検出値の高次の高調波を除去した値との差の成分を出力電圧の検出値が正か負かにより正負を反転させ、第１交直変換器の交流側電流の指令値とし、第１交直変換器の交流側電流の検出値を指令値に追従させる手段とを備えた無停電電源装置を提案する。
【００１８】
本発明は、入力端に接続した外部交流電源から交流電力を導入し、第１交直変換器の交流側を出力端に並列接続し、第２交直変換器の交流側を入力端と出力端との間に直列接続し、第１交直変換器および第２交直変換器の直流側に直流電力貯蔵手段および直流コンデンサを並列接続し、通常時は出力端に接続された負荷に交流電力を供給するとともに直流電力貯蔵手段を充電しておき、外部交流電源の停電時に第１交直変換器が直流電力貯蔵手段の直流電力を交流電力に変換し負荷に供給する無停電電源装置において、第１交直変換器の交流側電流を検出する手段と、第２交直変換器の直流側電流を検出する手段と、直流電力貯蔵手段の直流電圧を検出する手段と、無停電電源装置の出力電圧を検出する手段と、第２交直変換器の直流側電流検出値の高次の高調波成分を除去する手段とを備え、外部交流電源からの入力電圧と第２交直変換器の交流側電圧との和が所定の出力電圧となるように第２交直変換器を制御する手段と、直流電圧の検出値に応じた充電電流の指令値を算出し、充電電流の指令値と第２交直変換器の直流側電流の検出値の高次の高調波を除去した値との和を出力電圧の検出値が正か負かにより正負を反転させ、第１交直変換器の交流側電流の指令値とし、第１交直変換器の交流側電流の検出値に出力電圧の検出値と直流電圧の検出値との比を掛けた値を第１交直変換器の交流側電流の指令値に追従させる手段とを備えた無停電電源装置を提案する。
【００１９】
本発明は、また、入力端に接続した外部交流電源から交流電力を導入し、第１交直変換器の交流側を出力端に並列接続し、第２交直変換器の交流側を入力端と出力端との間に直列接続し、第１交直変換器および第２交直変換器の直流側に直流電力貯蔵手段および直流コンデンサを並列接続し、通常時は出力端に接続された負荷に交流電力を供給するとともに直流電力貯蔵手段を充電しておき、外部交流電源の停電時に第１交直変換器が直流電力貯蔵手段の直流電力を交流電力に変換し負荷に供給する無停電電源装置において、第１交直変換器の交流側電流を検出する手段と、第２交直変換器の交流側電流および電圧を検出する手段と、直流電力貯蔵手段の直流電圧を検出する手段と、無停電電源装置の出力電圧を検出する手段とを備え、外部交流電源からの入力電圧と第２交直変換器の交流側電圧との和が所定の出力電圧となるように第２交直変換器を制御する手段と、直流電圧の検出値に応じた充電電流の指令値を算出し、第２交直変換器の交流側電流の検出値に第２交直変換器の交流側電圧の検出値と直流電圧の検出値との比を掛けて第２交直変換器の直流側電流の検出値とし、充電電流の指令値と第２交直変換器の直流側電流の検出値との和を出力電圧の検出値が正か負かにより正負を反転させ、第１交直変換器の交流側電流の指令値とし、第１交直変換器の交流側電流の検出値に出力電圧の検出値と直流電圧の検出値との比を掛けた値を第１交直変換器の交流側電流の指令値に追従させる手段とを備えた無停電電源装置を提案する。
【００２０】
本発明は、さらに、入力端に接続した外部交流電源から交流電力を導入し、第１交直変換器の交流側を出力端に並列接続し、第２交直変換器の交流側を入力端と出力端との間に直列接続し、第１交直変換器および第２交直変換器の直流側に直流電力貯蔵手段および直流コンデンサを並列接続し、通常時は出力端に接続された負荷に交流電力を供給するとともに直流電力貯蔵手段を充電しておき、外部交流電源の停電時に第１交直変換器が直流電力貯蔵手段の直流電力を交流電力に変換し負荷に供給する無停電電源装置において、第１交直変換器の交流側電流を検出する手段と、第２交直変換器の交流側電流を検出する手段と、直流電力貯蔵手段の直流電圧を検出する手段と、無停電電源装置の出力電圧を検出する手段とを備え、外部交流電源からの入力電圧と第２交直変換器の交流側電圧との和が所定の出力電圧となるように第２交直変換器を制御する手段と、直流電圧の検出値に応じた充電電流の指令値を算出し、第２交直変換器の交流側電流の検出値に第２交直変換器の交流側電圧の指令値と直流電圧の検出値との比を掛けて第２交直変換器の直流側電流の検出値とし、充電電流の指令値と第２交直変換器の直流側電流の検出値との和を出力電圧の検出値が正か負かにより正負を反転させ、第１交直変換器の交流側電流の指令値とし、第１交直変換器の交流側電流の検出値に出力電圧の検出値と直流電圧の検出値との比を掛けた値を第１交直変換器の交流側電流の指令値に追従させる手段とを備えた無停電電源装置を提案する。
【発明の実施の形態】
【００２１】
《実施例１》
図１は、本発明による無停電電源装置の実施例１の系統構成を示すブロック図である。第１交直変換器１の交流側は、巻数比１：ｎ１の変圧器４を介して、出力端に並列接続してあり、フィルタ用コンデンサ７も、出力端に並列接続してある。この出力端には、負荷１０が接続される。
【００２２】
外部交流電源９が接続されている入力端からは、スイッチ１３を介して、交流電力が導入される。第２交直変換器２の交流側は、巻数比１：ｎ２の変圧器５を介して、入力端と出力端との間に直列接続してある。変圧器５と並列に、フィルタ用コンデンサ８を接続する。
【００２３】
第１交直変換器１および第２交直変換器２の直流側は、蓄電池３および直流コンデンサ６に並列接続してある。
【００２４】
検出器１１１は、第１交直変換器１の交流側電流Ｉinv1acを検出する。検出器１１２は、第２交直変換器２の直流側電流を検出する。検出器１１３は、蓄電池３の充電電流Ｉbattを検出する。検出器１１４は、出力電圧Ｖoutを検出する。検出器１１５は、直流電圧Ｖdcを検出する。ローパスフィルタ１６１は、直流側電流から高次の高調波成分をカットした直流側電流Ｉinv2dcを出力する。
【００２５】
指令値出力手段１２１は、直流電圧Ｖdcに応じた充電電流指令値Ｉbatt_refを出力する。演算増幅器１２２は、充電電流指令値Ｉbatt_refと充電電流Ｉbattとの誤差を増幅する。
【００２６】
正負極性判定手段１２３は、出力電圧Ｖoutの正負極性を出力する。すなわち、出力電圧Ｖoutが正のとき、１を出力し、負のとき、−１を出力する。
【００２７】
充電電流指令値Ｉbatt_refおよび充電電流Ｉbattの誤差成分と直流側電流Ｉinv2dcとを加算し、正負極性判定手段１２３の出力を掛けると、第１交直変換器１の交流側電流指令値Ｉinv1ac_refとなる。制御手段１２４は、交流側電流Ｉinv1acが交流側電流指令値Ｉinvac_refを追従するように、第１交直変換器１を制御する。
【００２８】
基準値出力手段１２５は、出力電圧基準値Ｖout_refを出力する。指令値出力手段１２６は、出力電圧Ｖoutが出力電圧基準値Ｖout_refとなるように第２交直変換器２の交流側電圧指令値Ｖ2ac_refを出力する。制御手段１２７は、交流側電圧指令値Ｖ2ac_refに基づいて、第２交直変換器２を制御する。
【００２９】
図２は、図１に示した無停電電源装置における電圧電流波形を示す図である。出力電圧Ｖoutは、一定の振幅の正弦波となる。負荷１０が、コンピュータ機器である場合、交流側入力電流Ｉin，交流側出力電流Ｉoutは、低次の高調波を多く含む波形となる。充電電流Ｉbattは、出力電圧Ｖoutの２倍の周波数のリプル電流を含むが、直流コンデンサ６の電流ＩＣdcは、第１交直変換器１のスイッチングに伴う高次の高調波電流のみである。
【００３０】
ここでは、無停電電源装置が、外部交流電源９からの入力電圧Ｖinと第２交直変換器２の交流側電圧との和を出力電圧Ｖoutとする場合の動作を説明した。
【００３１】
第２交直変換器２は、出力電圧Ｖoutを一定にするため、入力電圧Ｖinが低いときは、昇圧し、入力電圧Ｖinが高いときは、降圧する。
【００３２】
外部交流電源９が停電した場合は、スイッチ１３が開き、第１交直変換器１が蓄電池３の電力を交流に変換し、負荷１０に供給する。
【００３３】
本実施例１において、充電電流Ｉbattと直流側電流Ｉinv2dcとを検出すると、Ｖdc＝１とした場合の蓄電池３と第２交直変換器２との瞬時電力をそれぞれ検出していることになる。直流側電流Ｉinv2dcをフィードフォワード項として、充電電流指令値Ｉbatt_refおよび充電電流Ｉbattの誤差成分をゼロとするように、交流側電流指令値Ｉinv1ac_refを制御すると、第１交直変換器１は、蓄電池３の瞬時充電電力と第２交直変換器２の瞬時出力電力とを正確に供給できる。
【００３４】
ローパスフィルタ１６１が、高次の高調波成分をカットするので、第１交直変換器１は、第２交直変換器２が出力する低次の高調波成分のみを供給すればよいことになる。直流コンデンサ６には、高次の高調波は流れるが、低次の高調波と比較して、リプル耐量を小さくできる。
【００３５】
また、入力電圧Ｖinと第２交直変換器２の交流側電圧との和を出力し、入力電圧Ｖinの大小に応じて昇圧または降圧するので、負荷１０に安定した電圧を供給できる。
【００３６】
《実施例２》
図３は、本発明による無停電電源装置の実施例２の系統構成を示すブロック図である。第１交直変換器１の交流側は、巻数比１：ｎ１の変圧器４を介して、出力端に並列接続してあり、フィルタ用コンデンサ７も、出力端に並列接続してある。この出力端には、負荷１０が接続される。
【００３７】
外部交流電源９が接続されている入力端からは、スイッチ１３を介して、交流電力が導入される。第２交直変換器２の交流側は、巻数比１：ｎ２の変圧器５を介して、入力端と出力端との間に直列接続してある。変圧器５と並列に、フィルタ用コンデンサ８を接続する。
【００３８】
第１交直変換器１および第２交直変換器２の直流側は、蓄電池３および直流コンデンサ６に並列接続してある。
【００３９】
検出器１１１は、第１交直変換器１の交流側電流Ｉinv1acを検出する。検出器１１２は、第２交直変換器２の直流側電流を検出する。検出器１１４は、出力電圧Ｖoutを検出する。検出器１１５は、直流電圧Ｖdcを検出する。検出器１１６は、第１交直変換器１の直流側電流を検出する。ローパスフィルタ１６１は、直流側電流から高次の高調波成分をカットしたＩinv2dcを出力し、ローパスフィルタ１６２は、直流側電流から高次の高調波成分をカットしたＩinv1dcを出力する。
【００４０】
指令値出力手段１２１は、直流電圧Ｖdcに応じた充電電流指令値Ｉbatt_refを出力する。演算増幅器１２２は、充電電流Ｉbattおよび直流側電流Ｉinv2dcの和と直流側電流Ｉinv1dcとの誤差を増幅する手段である。
【００４１】
正負極性判定手段１２３は、Ｖoutの正負極性を出力する。出力電圧Ｖoutが正のとき、１を出力し、負のとき、−１を出力する。
【００４２】
充電電流指令値Ｉbatt_refおよび直流側電流Ｉinv2dcの和と直流側電流Ｉinv1dcとの誤差のＫ2倍の値に、正負極性判定手段１２３の出力を掛けると、第１交直変換器１の交流側電流指令値Ｉinv1ac_refとなる。制御手段１２４は、交流側電流Ｉinv1acが交流側電流指令値Ｉinvac_refを追従するように、第１交直変換器１を制御する。
【００４３】
基準値出力手段１２５は、出力電圧基準値Ｖout_refを出力する。指令値出力手段１２６は、出力電圧Ｖoutが出力電圧基準値Ｖout_refとなるように、第２交直変換器２の交流側電圧指令値Ｖ2ac_refを出力する。制御手段１２７は、交流側電圧指令値Ｖ2ac_refに基づいて、第２交直変換器２を制御する。
【００４４】
ここでは、無停電電源装置が、外部交流電源９からの入力電圧Ｖinと第２交直変換器２の交流側電圧との和を出力電圧Ｖoutとする場合の動作を説明した。
【００４５】
第２交直変換器２は、出力電圧Ｖoutを一定にするため、入力電圧Ｖinが低いときは、昇圧し、入力電圧Ｖinが高いときは、降圧する。
【００４６】
外部交流電源９が停電した場合は、スイッチ１３を開き、第１交直変換器１が蓄電池３の電力を交流に変換し、負荷１０に供給する。
【００４７】
本実施例２において、直流側電流Ｉinv1dcと直流側電流Ｉinv2dcを検出すると、Ｖdc＝１とした場合の第１交直変換器１と第２交直変換器２のそれぞれの瞬時電力を検出したことになる。充電電流指令値Ｉbatt_refおよび直流側電流Ｉinv2dcの和が直流側電流Ｉinv1dcと等しくなるように交流側電圧指令値Ｉinv1ac_refを制御すると、第１交直変換器１は、蓄電池３の瞬時充電電力と第２交直変換器２の瞬時出力電力とを供給できる。
【００４８】
ローパスフィルタ１６１および１６２が、高次の高調波成分をカットするので、第１交直変換器１は、第２交直変換器２が出力する低次の高調波成分のみを供給すればよいことになる。直流コンデンサ６には、高次の高調波は流れるが、低次の高調波と比較して、リプル耐量を小さくできる。
【００４９】
また、入力電圧Ｖinと第２交直変換器２の交流側電圧との和を出力し、入力電圧Ｖinの大小に応じて昇圧または降圧するので、負荷１０に安定した電圧を供給できる。
【００５０】
《実施例３》
図４は、本発明による無停電電源装置の実施例３の系統構成を示すブロック図である。第１交直変換器１の交流側は、巻数比１：ｎ１の変圧器４を介して、出力端に並列接続してあり、フィルタ用コンデンサ７も、出力端に並列接続してある。この出力端には、負荷１０が接続される。
【００５１】
外部交流電源９が接続されている入力端からは、スイッチ１３を介して、交流電力が導入される。第２交直変換器２の交流側は、巻数比１：ｎ２の変圧器５を介して、入力端と出力端との間に直列接続してある。変圧器５と並列に、フィルタ用コンデンサ８を接続する。
【００５２】
第１交直変換器１および第２交直変換器２の直流側は、蓄電池３および直流コンデンサ６に並列接続してある。
【００５３】
検出器１１１は、第１交直変換器１の交流側電流Ｉinv1acを検出する。検出器１１２は、第２交直変換器２の直流側電流を検出する。検出器１１４は、出力電圧Ｖoutを検出する。検出器１１５は、直流電圧Ｖdcを検出する。ローパスフィルタ１６１は、直流側電流から高次の高調波成分をカットしたＩinv2dcを出力する。
【００５４】
指令値出力手段１２１は、直流電圧Ｖdcに応じた充電電流の指令値Ｉbatt_refを出力する。
【００５５】
正負極性判定手段１２３は、出力電圧Ｖoutの正負極性を出力する。出力電圧Ｖoutが正のとき、１を出力し、負のとき、−１を出力する。
【００５６】
充電電流指令値Ｉbatt_refおよび直流側電流Ｉinv2dcの和に、正負極性判定手段１２３の出力を掛けると、第１交直変換器１の交流側電流指令値Ｉinv1ac_refとなる。演算手段１２８は、出力電圧Ｖoutと直流電圧Ｖdcとの比を求める。すなわち、変圧器４の巻数換算のため、｜Ｖout｜／（n1・Ｖdc）を演算して出力する。制御手段１２４は、交流側電流Ｉinv1acに演算手段１２８の出力を掛けた値が交流側電流指令値Ｉinvac_refを追従するように、第１交直変換器１を制御する。
【００５７】
基準値出力手段１２５は、出力電圧基準値Ｖout_refを出力する。指令値出力手段１２６は、出力電圧Ｖoutが出力電圧基準値Ｖout_refとなるように、第２交直変換器２の交流側電圧指令値Ｖ2ac_refを出力する。制御手段１２７は、交流側電圧指令値Ｖ2ac_refに基づいて、第２交直変換器２を制御する。
【００５８】
ここでは、無停電電源装置が、外部交流電源９からの入力電圧Ｖinと第２交直変換器２の交流側電圧との和を出力電圧Ｖoutとする場合の動作を説明した。
【００５９】
第２交直変換器２は、出力電圧Ｖoutを一定にするため、入力電圧Ｖinが低いときは、昇圧し、入力電圧Ｖinが高いときは、降圧する。
【００６０】
外部交流電源９が停電した場合は、スイッチ１３が開き、第１交直変換器１が蓄電池３の電力を交流に変換し、負荷１０に供給する。
【００６１】
本実施例３において、直流側電流Ｉinv2dcを検出すると、Ｖdc＝１とした場合の第２交直変換器２の瞬時電力を検出したことになる。また、交流側電流Ｉinv1acに出力電圧Ｖoutと直流電圧Ｖdcとの比を掛けて、第１交直変換器１の直流電圧Ｖdc＝１とした場合の瞬時電力を推定する。この第１交直変換器１の推定瞬時電力を交流側電圧指令値Ｉinv1ac_refに追従させるので、第１交直変換器１は、蓄電池３の瞬時充電電力と第２交直変換器２の瞬時出力電力とを供給できる。
【００６２】
ローパスフィルタ１６１は、高次の高調波成分をカットするので、第１交直変換器１は、第２交直変換器２が出力する低次の高調波成分のみを供給すればよいことになる。直流コンデンサ６には、高次の高調波が流れるが、低次の高調波と比較して、リプル耐量を小さくできる。
【００６３】
また、入力電圧Ｖinと第２交直変換器２の交流側電圧との和を出力し、入力電圧Ｖinの大小に応じて昇圧または降圧するので、負荷１０に安定した電圧を供給できる。
【００６４】
《実施例４》
図５は、本発明による無停電電源装置の実施例４の系統構成を示すブロック図である。第１交直変換器１の交流側は、巻数比１：ｎ１の変圧器４を介して、出力端に並列接続してあり、フィルタ用コンデンサ７も、出力端に並列接続してある。この出力端には、負荷１０が接続される。
【００６５】
第１交直変換器１および第２交直変換器２の直流側は、蓄電池３および直流コンデンサ６に並列に接続してある。
【００６６】
外部交流電源９が接続されている入力端からは、スイッチ１３を介して、交流電力が導入される。第２交直変換器２の交流側は、巻数比１：ｎ２の変圧器５を介して、入力端と出力端との間に直列接続してある。変圧器５と並列に、フィルタ用コンデンサ８を接続する。
【００６７】
検出器１１１は、第１交直変換器１の交流側電流Ｉinv1acを検出する。検出器１１４は、出力電圧Ｖoutを検出する。検出器１１５は、直流電圧Ｖdcを検出する。検出器１１７は、第２交直変換器２の交流側電流Ｉinv2acを検出する。検出器１１８は、第２交直変換器２の交流側電圧Ｖ2acを検出する。
【００６８】
指令値出力手段１２１は、直流電圧Ｖdcに応じた充電電流の指令値Ｉbatt_refを出力する。演算手段１２９は、第２交直変換器２の交流側電圧Ｖ2acと直流電圧Ｖdcとの比を求める。すなわち、Ｖ2ac／（n2・Ｖdc）を演算して出力する。
【００６９】
交流側電流Ｉinv2acと演算手段１２９の出力とを掛けると、等価的に第２交直変換器２の直流側電流をローパスフィルタに通した値となる。
【００７０】
正負極性判定手段１２３は、出力電圧Ｖoutの正負極性を出力する。出力電圧Ｖoutが正のとき、１を出力し、負のとき、−１を出力する。
【００７１】
交流側電流Ｉinv2acに演算手段１２９の出力を掛けた値と充電電流指令値Ｉbatt_refとの和に、正負極性判定手段１２３の出力を掛けると、第１交直変換器１の交流側電流指令値Ｉinv1ac_refとなる。演算手段１２８は、出力電圧Ｖoutと直流電圧Ｖdcとの比を求める。すなわち、変圧器７の巻数換算のため、｜Ｖout｜／（n1・Ｖdc）を演算して出力する。制御手段１２４は、交流側電流Ｉinv1acに演算手段１２８の出力を掛けた値が交流側電流指令値Ｉinvac_refを追従するように、第１交直変換器１を制御する。
【００７２】
基準値出力手段１２５は、出力電圧基準値Ｖout_refを出力する。指令値出力手段１２６は、出力電圧Ｖoutが出力電圧基準値Ｖout_refとなるように、第２交直変換器２の交流側電圧指令値Ｖ2ac_refを出力する。制御手段１２７は、交流側電圧指令値Ｖ2ac_refに基づき、第２交直変換器２を制御する。
【００７３】
ここでは、無停電電源装置が、外部交流電源９からの入力電圧Ｖinと第２交直変換器２の交流側電圧の和を出力電圧Ｖoutとする場合の動作を説明した。
【００７４】
第２交直変換器２は、出力電圧Ｖoutを一定にするため、入力電圧Ｖinが低いときは、昇圧し、入力電圧Ｖinが高いときは、降圧する。
【００７５】
外部交流電源９が停電した場合は、スイッチ１３を開き、第１交直変換器１が蓄電池３の電力を交流に変換し、負荷１０に供給する。
【００７６】
本実施例４は、検出対象が第２交直変換器２の直流側電流Ｉinv2dcであった実施例３とは、第２交直変換器２の交流側電流Ｉinv2acを検出する点で異なるが、実施例３と同様の効果が得られる。
【００７７】
《実施例５》
図６は、本発明による無停電電源装置の実施例５の系統構成を示すブロック図である。第１交直変換器１の交流側は、巻数比１：ｎ１の変圧器４を介して、出力端に並列接続してあり、フィルタ用コンデンサ７も、出力端に並列接続してある。この出力端には、負荷１０が接続される。
【００７８】
外部交流電源９が接続されている入力端からは、スイッチ１３を介して、交流電力が導入される。第２交直変換器２の交流側は、巻数比１：ｎ２の変圧器５を介して、入力端と出力端との間に直列接続してある。変圧器５と並列に、フィルタ用コンデンサ８を接続する。
【００７９】
第１交直変換器１および第２交直変換器２の直流側は、蓄電池３および直流コンデンサ６に並列接続してある。
【００８０】
検出器１１１は、第１交直変換器１の交流側電流Ｉinv1acを検出する。検出器１１４は、出力電圧Ｖoutを検出する。検出器１１５は、直流電圧Ｖdcを検出する。検出器１１７は、第２交直変換器２の交流側電流Ｉinv2acを検出する。
【００８１】
指令値出力手段１２１は、直流電圧Ｖdcに応じた充電電流の指令値Ｉbatt_refを出力する。演算手段１２９は、第２交直変換器２の交流側電圧と直流電圧Ｖdcとの比を求める。ここでは、第２交直変換器２の交流側電圧を検出せずに、指令値を用いて変圧器８の巻数を換算し、Ｖ2ac_ref／（n2・Ｖdc）を演算して出力する。交流側電流Ｉinv2acに演算手段１２９の出力を掛けると、等価的に第２交直変換器２の直流側電流をローパスフィルタに通した値となる。
【００８２】
正負極性判定手段１２３は、出力電圧Ｖoutの正負極性を出力する。出力電圧Ｖoutが正のとき、１を出力し、負のとき、−１を出力する。
【００８３】
交流側電流Ｉinv2acに演算手段１２９の出力を掛けた値と充電電流指令値Ｉbatt_refとの和に、正負極性判定手段１２３の出力を掛けると、第１交直変換器１の交流側電流指令値Ｉinv1ac_refになる。演算手段１２８は、出力電圧Ｖoutと直流電圧Ｖdcとの比を求める。変圧器７の巻数を換算するため、｜Ｖout｜／（n1・Ｖdc）を演算して出力する。制御手段１２４は、交流側電流Ｉinv1acに演算手段１２８の出力を掛けた値が交流側電流指令値Ｉinvac_refに追従するように、第１交直変換器１を制御する。
【００８４】
基準値出力手段１２５は、出力電圧基準値Ｖout_refを出力する。指令値出力手段１２６は、出力電圧Ｖoutが出力電圧基準値Ｖout_refとなるように、第２交直変換器２の交流側電圧指令値Ｖ2ac_refを出力する。第２交直変換器制御手段１２７は、交流側電圧指令値Ｖ2ac_refにより、第２交直変換器２を制御する。
【００８５】
ここでは、無停電電源装置が、外部交流電源９からの入力電圧Ｖinと第２交直変換器２の交流側電圧との和を出力する場合の動作を説明した。
【００８６】
出力電圧Ｖoutを一定にするため、第２交直変換器２は、入力電圧Ｖinが低いときは、昇圧し、入力電圧Ｖinが高いときは、降圧する。
【００８７】
外部交流電源９が停電した場合は、スイッチ１３を開き、第１交直変換器１が、蓄電池３の電力を交流に変換し、負荷１０に供給する。
【００８８】
本実施例５は、第２交直変換器２の交流側電圧であった実施例３とは、第２交直変換器２の直流側電圧を検出する点で異なるが、実施例３と同様の効果が得られる。検出対象が第２交直変換器２の直流側電流Ｉinv2dcであった実施例３とは、第１交直変換器１の交流側電流Ｉinv１acを検出する点で異なるが、実施例３と同様の効果が得られる。
【００８９】
《第１交直変換器１の実施例１》
図７は、本発明の各実施例における第１交直変換器１および第１交直変換器制御手段１２４の実施例１の回路構成を示す図である。第１交直変換器１は、パワーＭＯＳＦＥＴ１０１〜１０４を用いたフルブリッジ構成である。比例積分演算器１２４１は、交流側電流指令値Ｉinv1ac_refと交流側電流Ｉinv1acとの誤差を比例積分演算する。鋸歯状波発生回路１２４２，１２４３は、それぞれ所定のキャリア周波数を持ち、０〜１および−１〜０で変化する波形を出力する。比較器１２４４は、（１２４１の出力）≧（１２４２の出力）で１を出力し、（１２４１の出力）＜（１２４２の出力）で０を出力する。比較器１２４５は、（１２４１の出力）＜（１２４３の出力）で１を出力し、（１２４１の出力）≧（１２４３の出力）で０を出力する。ゲート駆動回路１２４６１〜１２４６４は、それぞれ１０１〜１０４を駆動する。入力が正のとき、パワーＭＯＳＦＥＴをＯＮさせ、入力が負のとき、パワーＭＯＳＦＥＴをＯＦＦさせる。
【００９０】
《第１交直変換器１の実施例２》
図８は、本発明の各実施例における第１交直変換器１および第１交直変換器制御手段１２４の実施例２の回路構成を示す図である。第１交直変換器１は、パワーＭＯＳＦＥＴ１０１〜１０４を用いたフルブリッジ構成である。比較器１２４７は、ヒステリシス付きの比較器である。すなわち、交流側電流指令値Ｉin1vac_refと交流側電流Ｉinv1acとの大小関係の変化で、１，０を出力する。極性判定回路１２４８は、出力電圧Ｖoutの極性を判定する。出力電圧Ｖoutが正のとき、１を出力し、負のとき、０を出力する。ゲート駆動回路１２４６１〜１２４６４は、それぞれパワーＭＯＳＦＥＴ１０１〜１０４を駆動する。入力が正のとき、パワーＭＯＳＦＥＴをＯＮさせ、入力が負のとき、パワーＭＯＳＦＥＴをＯＦＦさせる。
【００９１】
《第２交直変換器２の実施例》
図９は、本発明の各実施例における第２交直変換器２の回路構成と制御回路の具体例を示す図である。第２交直変換器２は、パワーＭＯＳＦＥＴ２０１〜２０４を用いたフルブリッジ構成である。鋸歯状波発生回路１２７１，１２７２は、それぞれ所定のキャリア周波数で０〜１および−１〜０で変化する波形を出力する。比較器１２７３は、交流側電圧指令値Ｖ2ac_ref≧（１２７１の出力）で１を出力し、交流側電圧指令値Ｖ2ac_ref＜（１２７１の出力）で０を出力する。比較器１２７４は、交流側電圧指令値Ｖ2ac_ref＜（１２７２の出力）で１を出力し、交流側電圧指令値Ｖ2ac_ref≧（１２７２の出力）で０を出力する。ゲート駆動回路１２７５１〜１２７５４は、それぞれパワーＭＯＳＦＥＴ２０１〜２０４を駆動する。入力が正のとき、パワーＭＯＳＦＥＴをＯＮさせ、入力が負のとき、パワーＭＯＳＦＥＴをＯＦＦさせる。
【発明の効果】
【００９２】
本発明によれば、第１交直変換器および第２交直変換器の瞬時電力をそれぞれ検出しまたは推定する手段と、外部交流電源からの入力電圧と第２交直変換器の交流側電圧との和が所定の出力電圧になるように第２交直変換器を制御する手段と、第２交直変換器が出力する瞬時電力と蓄電池への瞬時充電電力とを供給するように第１交直変換器を制御する手段とを備えたので、直流部分に蓄電池放電防止用リアクトルを接続したり、直流コンデンサのリプル耐量を上げたりせずに、第１交直変換器と第２交直変換器との間で電力を授受して、負荷に所定の電圧を供給するとともに、蓄電池を安定に充電でき、しかも、蓄電池放電防止用リアクトルが不要となりコンデンサを小型化した分だけ、装置全体を小型化しコストダウンできる無停電電源装置が得られる。
【図面の簡単な説明】
【００９３】
【図１】本発明による無停電電源装置の実施例１の系統構成を示すブロック図である。
【図２】図１に示した無停電電源装置における電圧電流波形を示す図である。
【図３】本発明による無停電電源装置の実施例２の系統構成を示すブロック図である。
【図４】本発明による無停電電源装置の実施例３の系統構成を示すブロック図である。
【図５】本発明による無停電電源装置の実施例４の系統構成を示すブロック図である。
【図６】本発明による無停電電源装置の実施例５の系統構成を示すブロック図である。
【図７】本発明の各実施例における第１交直変換器および第１交直変換器制御手段の実施例１の回路構成を示す図である。
【図８】本発明の各実施例における第１交直変換器および第１交直変換器制御手段の実施例２の回路構成を示す図である。
【図９】本発明の各実施例における第２交直変換器および第２交直変換器制御手段の実施例の回路構成を示す図である。
【図１０】従来の無停電電源装置の一例の系統構成を示すブロック図である。
【図１１】図１０に示した従来の無停電電源装置における電圧電流波形を示す図である。
【符号の説明】
【００９４】
１第１交直変換器
２第２交直変換器
３蓄電池
４変圧器
５変圧器
６直流コンデンサ
７フィルタ用コンデンサ
８フィルタ用コンデンサ
９交流電源
１０負荷
１２制御回路
１３スイッチ
１４フィルタ用リアクトル
１５蓄電池放電防止用リアクトル
１０１〜１０４パワーＭＯＳＦＥＴ
１１０〜１１９電流および電圧検出器
１２１蓄電池充電電流指令値出力手段
１２２演算増幅器
１２３正負極性判定手段
１２４第１交直変換器制御手段
１２４１比例積分演算器
１２４２鋸歯状波発生器
１２４３鋸歯状波発生器
１２４４比較器
１２４５比較器
１２４６１〜１２４６４ゲート駆動回路
１２４７ヒステリシス付き比較器
１２４８入力正負極性判定手段
１２５出力電圧基準値出力手段
１２６交流側電圧指令値制御手段
１２７第２交直変換器制御手段
１２７１鋸歯状波発生器
１２７２鋸歯状波発生器
１２７３比較器
１２７４比較器
１２７５１〜１２７５４ゲート駆動回路
１２８除算器
１２９除算器
１６１ローパスフィルタ
１６２ローパスフィルタ
２０１〜２０４パワーＭＯＳＦＥＴBACKGROUND OF THE INVENTION
[0001]
The present invention relates to an uninterruptible power supply, and more particularly to a circuit configuration for supplying stable power to a load and optimally charging a storage battery.
[Prior art]
[0002]
An uninterruptible power supply unit in which the first AC / DC converter is connected in parallel to the output end and the second AC / DC converter is connected in series between the input end and the output end is IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL.13, No.3 , MAY 1998, “A Novel On-Line UPS with Universal Filtering Capabilities”.
[0003]
FIG. 10 is a block diagram showing a system configuration of an example of a conventional uninterruptible power supply. The uninterruptible power supply device includes a first AC / DC converter 1 and a second AC / DC converter 2. The AC side of the first AC / DC converter 1 is connected in parallel to the output end via the filter reactor 14, and the filter capacitor 7 is also connected in parallel to the output end. A load 10 is connected to the output end.
[0004]
AC power is introduced through the switch 13 from the input end to which the external AC power source 9 is connected. The AC side of the second AC / DC converter 2 is connected in series between the input end and the output end via the transformer 5 having a turns ratio of 1: n2.
[0005]
A DC capacitor 6 is connected in parallel to the DC side of the first AC / DC converter 1, and the storage battery 3 is connected via a storage battery discharge prevention reactor 15.
[0006]
The current detector 119 detects the input current Iin. The current detector 113 detects the storage battery current Ibatt. The current detector 110 detects the output current Iout. The voltage detector 114 detects the output voltage Vout. The control circuit 12 executes a control calculation based on the detected current value and the detected voltage value, and the first circuit , Second The AC / DC converters 1 and 2 are controlled.
[0007]
When the external AC power supply 9 fails, the switch 13 is opened, the power of the storage battery 3 is converted into AC by the first AC / DC converter 1, and AC power is supplied to the load 10.
[0008]
In a normal state where the external AC power supply 9 is normal, the control circuit 12 calculates the average power of the load 10 from the output voltage Vout and the output current Iout. The second AC / DC converter 2 supplies the calculated average power to the load 10 and charging power to the storage battery 3, Control circuit 12 Controls the voltage of the second AC / DC converter 2 so that the input current Iin becomes a sine wave. The control circuit 12 also estimates the input current of the first AC / DC converter 1 from the output voltage Vout, the input current Iin, and the output current Iout by a complete dimension observer, and makes the output voltage Vout constant by finite establishment response control. The voltage of the 1st AC / DC converter 1 is controlled so that it may be kept at.
[0009]
As described above, if the technique of the above-mentioned document is used, even if the input power supply 9 or the load 10 changes suddenly, the input current Iin is maintained as a sine wave, and stable power is supplied to the load 10 and the storage battery 3 by the function of the active filter. It is supposed to be possible.
[Problems to be solved by the invention]
[0010]
Uninterruptible power supplies are most widely used in computer equipment. These computer devices contain many low-order harmonics such as the fifth, seventh, ninth and eleventh orders.
[0011]
In the conventional uninterruptible power supply, if the power supplied to the load by the second AC / DC converter 2 is calculated as an average value and the input current Iin is maintained as a sine wave, the charging current is reduced by the amount of harmonics. It is said.
[0012]
If the charging current is sufficiently larger than the harmonics, there is no problem. However, when the storage battery 3 is nearly fully charged, the charging current must be reduced, so that power including harmonic components is supplied from the direct current portion to the load 10. At this time, in order not to discharge the storage battery 3, it is necessary to insert a storage battery discharge preventing reactor 15 and make the impedance of the storage battery 3 with respect to the lower harmonics sufficiently larger than the DC capacitor 6.
[0013]
FIG. 11 is a diagram showing a voltage-current waveform in the conventional uninterruptible power supply shown in FIG. The output voltage Vout and the input current Iin are controlled to be a sine wave. Since the load 10 is assumed to be a computer device, the load current Iout has a waveform including many low-order harmonics. The charging current Ibatt is substantially DC due to the action of the reactor 15, but the current ICdc of the DC capacitor 6 includes the output current Iout in addition to the higher-order harmonic components accompanying the switching of the first AC / DC converter 1. Low-order harmonic components flow.
[0014]
Therefore, it is necessary to increase the ripple tolerance of the DC capacitor 6. Since the storage battery discharge preventing reactor 15 and the DC capacitor 6 having a large ripple resistance are required, the volume of the uninterruptible power supply increases. In addition, since the control calculation becomes complicated, a high-function microcomputer must be installed.
[0015]
The object of the present invention is to transfer power between the first AC / DC converter and the second AC / DC converter without increasing the ripple tolerance of the DC capacitor or providing a reactor for preventing the battery discharge, and The object is to provide an uninterruptible power supply that can be stably charged.
[Means for Solving the Problems]
[0016]
In order to achieve the above object, the present invention introduces AC power from an external AC power source connected to the input end, connects the AC side of the first AC / DC converter in parallel to the output end, and sets the AC of the second AC / DC converter. Side is connected in series between the input end and output end, DC power storage means and DC capacitor are connected in parallel on the DC side of the first AC / DC converter and the second AC / DC converter, and normally connected to the output end AC power is supplied to the load and the DC power storage means is charged, and the first AC / DC converter converts the DC power of the DC power storage means to AC power and supplies it to the load when the external AC power supply fails In the power supply device, means for detecting the AC side current of the first AC / DC converter, means for detecting the DC side current of the second AC / DC converter, means for detecting the charging current and DC voltage of the DC power storage means, Check the output voltage of the UPS And means for removing higher-order harmonic components of the DC-side current detection value of the second AC / DC converter, and the sum of the input voltage from the external AC power supply and the AC-side voltage of the second AC / DC converter Means for controlling the second AC / DC converter so that becomes a predetermined output voltage, a command value for the charging current according to the detected value of the DC voltage is calculated, and the command value of the charging current and the detected value of the charging current are The sum of the error component and the value obtained by removing high-order harmonics of the DC side current detection value of the second AC / DC converter is inverted depending on whether the detected value of the output voltage is positive or negative, and the first AC / DC converter's Proposed is an uninterruptible power supply comprising a command value for an alternating current and a means for causing the detected value of the alternating current of the first AC / DC converter to follow the command value.
[0017]
The present invention further introduces AC power from an external AC power source connected to the input terminal, connects the AC side of the first AC / DC converter in parallel to the output terminal, and outputs the AC side of the second AC / DC converter to the input terminal and the output terminal. DC power storage means and a DC capacitor are connected in parallel to the DC side of the first AC / DC converter and the second AC / DC converter, and AC power is normally supplied to the load connected to the output terminal. In the uninterruptible power supply apparatus, the first AC / DC converter converts the DC power of the DC power storage means into AC power and supplies it to the load at the time of power failure of the external AC power supply. Means for detecting the DC side current and AC side current of the AC / DC converter, means for detecting the DC side current of the second AC / DC converter, means for detecting the DC voltage of the DC power storage means, and an uninterruptible power supply Means for detecting the output voltage; Means for removing high-order harmonic components of the DC-side current detection value of the AC / DC converter and the DC-side current detection value of the second AC / DC converter, respectively, and an input voltage from the external AC power source and the second AC / DC converter Means for controlling the second AC / DC converter so that the sum of the AC voltage and the AC side voltage becomes a predetermined output voltage, and calculates a charging current command value corresponding to the detected value of the DC voltage, and the charging current command value and The difference between the sum of the values obtained by removing high-order harmonics of the DC side current detection value of the second AC / DC converter and the value obtained by removing high-order harmonics of the DC side current detection value of the first AC / DC converter The component is inverted depending on whether the detected value of the output voltage is positive or negative, and is used as the command value for the AC side current of the first AC / DC converter, and the detected value of the AC side current of the first AC / DC converter is made to follow the command value. An uninterruptible power supply with means is proposed.
[0018]
The present invention introduces AC power from an external AC power source connected to the input end, connects the AC side of the first AC / DC converter in parallel to the output end, and connects the AC side of the second AC / DC converter to the input end and the output end. Are connected in series, DC power storage means and a DC capacitor are connected in parallel on the DC side of the first AC / DC converter and the second AC / DC converter, and AC power is supplied to a load connected to the output terminal in normal times. In the uninterruptible power supply, the DC power storage means is charged and the first AC / DC converter converts the DC power of the DC power storage means into AC power and supplies it to the load at the time of power failure of the external AC power supply. Means for detecting the AC side current of the converter, means for detecting the DC side current of the second AC / DC converter, means for detecting the DC voltage of the DC power storage means, means for detecting the output voltage of the uninterruptible power supply And the DC side current of the second AC / DC converter And a second AC / DC converter so that the sum of the input voltage from the external AC power source and the AC side voltage of the second AC / DC converter becomes a predetermined output voltage. The charging current command value corresponding to the DC voltage detection value is calculated, and the higher harmonics of the charging current command value and the DC current detection value of the second AC / DC converter are removed. The sum of the detected value and the detected value of the output voltage is inverted depending on whether the detected value of the output voltage is positive or negative, and used as the command value for the AC side current of the first AC / DC converter, and output to the AC side current detected value of the first AC / DC converter Proposed is an uninterruptible power supply comprising means for causing a value obtained by multiplying a ratio of a detected value of voltage to a detected value of DC voltage to follow a command value of an AC side current of a first AC / DC converter.
[0019]
The present invention also introduces AC power from an external AC power source connected to the input terminal, connects the AC side of the first AC / DC converter in parallel to the output terminal, and outputs the AC side of the second AC / DC converter to the input terminal and the output terminal. DC power storage means and a DC capacitor are connected in parallel to the DC side of the first AC / DC converter and the second AC / DC converter, and AC power is normally supplied to the load connected to the output terminal. In the uninterruptible power supply apparatus, the first AC / DC converter converts the DC power of the DC power storage means into AC power and supplies it to the load at the time of power failure of the external AC power supply. Means for detecting AC side current of AC / DC converter, means for detecting AC side current and voltage of second AC / DC converter, means for detecting DC voltage of DC power storage means, output voltage of uninterruptible power supply And means for detecting the external Means for controlling the second AC / DC converter so that the sum of the input voltage from the AC power source and the AC side voltage of the second AC / DC converter becomes a predetermined output voltage, and a charging current corresponding to the detected value of the DC voltage. The command value is calculated, and the detected value of the AC side current of the second AC / DC converter is multiplied by the ratio of the detected value of the AC side voltage of the second AC / DC converter and the detected value of the DC voltage to obtain the DC of the second AC / DC converter. The first AC / DC converter converts the detected value of the output current to the sum of the command value of the charging current and the detected value of the DC side current of the second AC / DC converter depending on whether the detected value of the output voltage is positive or negative. The AC side current of the first AC / DC converter is a value obtained by multiplying the detected value of the AC side current of the first AC / DC converter by the ratio of the detected value of the output voltage and the detected value of the DC voltage. An uninterruptible power supply device having means for following the command value is proposed.
[0020]
The present invention further introduces AC power from an external AC power source connected to the input terminal, connects the AC side of the first AC / DC converter in parallel to the output terminal, and outputs the AC side of the second AC / DC converter to the input terminal and the output terminal. DC power storage means and a DC capacitor are connected in parallel to the DC side of the first AC / DC converter and the second AC / DC converter, and AC power is normally supplied to the load connected to the output terminal. In the uninterruptible power supply apparatus, the first AC / DC converter converts the DC power of the DC power storage means into AC power and supplies it to the load at the time of power failure of the external AC power supply. Means for detecting AC side current of AC / DC converter, means for detecting AC side current of second AC / DC converter, means for detecting DC voltage of DC power storage means, and detecting output voltage of uninterruptible power supply And an external AC power source Means for controlling the second AC / DC converter so that the sum of the input voltage and the AC side voltage of the second AC / DC converter becomes a predetermined output voltage, and a charging current command value corresponding to the detected value of the DC voltage Is calculated by multiplying the detected value of the AC side current of the second AC / DC converter by the ratio of the command value of the AC side voltage of the second AC / DC converter and the detected value of the DC voltage, and the DC side current of the second AC / DC converter. The positive / negative is inverted depending on whether the detected value of the output voltage is positive or negative, and the sum of the command value of the charging current and the detected value of the DC side current of the second AC / DC converter is AC of the first AC / DC converter The command value of the AC current of the first AC / DC converter is obtained by multiplying the detected value of the AC side current of the first AC / DC converter by the ratio of the detected value of the output voltage and the detected value of the DC voltage. An uninterruptible power supply with a means for following the value is proposed.
DETAILED DESCRIPTION OF THE INVENTION
[0021]
Example 1
FIG. 1 is a block diagram showing a system configuration of Embodiment 1 of the uninterruptible power supply according to the present invention. The AC side of the first AC / DC converter 1 is connected in parallel to the output end via the transformer 4 having a turns ratio of 1: n1, and the filter capacitor 7 is also connected in parallel to the output end. A load 10 is connected to the output end.
[0022]
AC power is introduced through the switch 13 from the input end to which the external AC power source 9 is connected. The AC side of the second AC / DC converter 2 is connected in series between the input end and the output end via the transformer 5 having a turns ratio of 1: n2. A filter capacitor 8 is connected in parallel with the transformer 5.
[0023]
The DC side of the first AC / DC converter 1 and the second AC / DC converter 2 is connected in parallel to the storage battery 3 and the DC capacitor 6.
[0024]
The detector 111 detects the AC side current Iinv1ac of the first AC / DC converter 1. The detector 112 detects the direct current on the second AC / DC converter 2. The detector 113 detects the charging current Ibatt of the storage battery 3. The detector 114 detects the output voltage Vout. The detector 115 detects a DC voltage Vdc. The low-pass filter 161 outputs a direct current Iinv2dc obtained by cutting high-order harmonic components from the direct current.
[0025]
The command value output means 121 outputs a charging current command value Ibatt_ref corresponding to the DC voltage Vdc. The operational amplifier 122 amplifies an error between the charging current command value Ibatt_ref and the charging current Ibatt.
[0026]
The positive / negative polarity determining means 123 outputs the positive / negative polarity of the output voltage Vout. That is, when the output voltage Vout is positive, 1 is output, and when it is negative, -1 is output.
[0027]
When the charging current command value Ibatt_ref and the error component of the charging current Ibatt are added to the direct current Iinv2dc and multiplied by the output of the positive / negative polarity determination means 123, the alternating current command value Iinv1ac_ref of the first AC / DC converter 1 is obtained. The control means 124 controls the first AC / DC converter 1 so that the AC side current Iinv1ac follows the AC side current command value Iinvac_ref.
[0028]
The reference value output means 125 outputs the output voltage reference value Vout_ref. The command value output means 126 outputs the AC side voltage command value V2ac_ref of the second AC / DC converter 2 so that the output voltage Vout becomes the output voltage reference value Vout_ref. The control means 127 controls the second AC / DC converter 2 based on the AC side voltage command value V2ac_ref.
[0029]
FIG. 2 is a diagram showing a voltage-current waveform in the uninterruptible power supply shown in FIG. The output voltage Vout is a sine wave having a constant amplitude. When the load 10 is a computer device, the AC-side input current Iin and the AC-side output current Iout have waveforms that contain many low-order harmonics. The charging current Ibatt includes a ripple current having a frequency twice that of the output voltage Vout, but the current ICdc of the DC capacitor 6 is only a high-order harmonic current associated with the switching of the first AC / DC converter 1.
[0030]
Here, the operation when the uninterruptible power supply apparatus uses the sum of the input voltage Vin from the external AC power supply 9 and the AC side voltage of the second AC / DC converter 2 as the output voltage Vout has been described.
[0031]
In order to keep the output voltage Vout constant, the second AC / DC converter 2 increases the voltage when the input voltage Vin is low, and decreases the voltage when the input voltage Vin is high.
[0032]
When the external AC power supply 9 fails, the switch 13 is opened, and the first AC / DC converter 1 converts the electric power of the storage battery 3 into AC and supplies it to the load 10.
[0033]
In the first embodiment, when the charging current Ibatt and the DC side current Iinv2dc are detected, the instantaneous powers of the storage battery 3 and the second AC / DC converter 2 when Vdc = 1 are detected. When the AC side current command value Iinv1ac_ref is controlled so that the error component of the charging current command value Ibatt_ref and the charging current Ibatt is zero using the DC side current Iinv2dc as a feedforward term, the first AC / DC converter 1 The instantaneous charging power and the instantaneous output power of the second AC / DC converter 2 can be accurately supplied.
[0034]
Since the low-pass filter 161 cuts higher-order harmonic components, the first AC / DC converter 1 only needs to supply the lower-order harmonic components output by the second AC / DC converter 2. Although higher-order harmonics flow through the DC capacitor 6, the ripple tolerance can be reduced as compared with the lower-order harmonics.
[0035]
In addition, the sum of the input voltage Vin and the AC side voltage of the second AC / DC converter 2 is output, and the voltage is stepped up or down according to the magnitude of the input voltage Vin, so that a stable voltage can be supplied to the load 10.
[0036]
Example 2
FIG. 3 is a block diagram showing a system configuration of Embodiment 2 of the uninterruptible power supply according to the present invention. The AC side of the first AC / DC converter 1 is connected in parallel to the output end via the transformer 4 having a turns ratio of 1: n1, and the filter capacitor 7 is also connected in parallel to the output end. A load 10 is connected to the output end.
[0037]
AC power is introduced through the switch 13 from the input end to which the external AC power source 9 is connected. The AC side of the second AC / DC converter 2 is connected in series between the input end and the output end via the transformer 5 having a turns ratio of 1: n2. A filter capacitor 8 is connected in parallel with the transformer 5.
[0038]
The DC side of the first AC / DC converter 1 and the second AC / DC converter 2 is connected in parallel to the storage battery 3 and the DC capacitor 6.
[0039]
The detector 111 detects the AC side current Iinv1ac of the first AC / DC converter 1. The detector 112 detects the direct current on the second AC / DC converter 2. The detector 114 detects the output voltage Vout. The detector 115 detects a DC voltage Vdc. The detector 116 detects the direct current on the first AC / DC converter 1. The low-pass filter 161 outputs Iinv2dc obtained by cutting high-order harmonic components from the direct current, and the low-pass filter 162 outputs Iinv1dc obtained by cutting high-order harmonic components from the direct current.
[0040]
The command value output means 121 outputs a charging current command value Ibatt_ref corresponding to the DC voltage Vdc. The operational amplifier 122 is means for amplifying an error between the sum of the charging current Ibatt and the DC side current Iinv2dc and the DC side current Iinv1dc.
[0041]
The positive / negative polarity determining means 123 outputs the positive / negative polarity of Vout. When the output voltage Vout is positive, 1 is output, and when it is negative, -1 is output.
[0042]
By multiplying the value of K2 times the error between the sum of the charging current command value Ibatt_ref and the DC side current Iinv2dc and the DC side current Iinv1dc by the output of the positive / negative polarity determining means 123, the AC side current command value of the first AC / DC converter 1 is obtained. Iinv1ac_ref. The control means 124 controls the first AC / DC converter 1 so that the AC side current Iinv1ac follows the AC side current command value Iinvac_ref.
[0043]
The reference value output means 125 outputs the output voltage reference value Vout_ref. The command value output means 126 outputs the AC side voltage command value V2ac_ref of the second AC / DC converter 2 so that the output voltage Vout becomes the output voltage reference value Vout_ref. The control means 127 controls the second AC / DC converter 2 based on the AC side voltage command value V2ac_ref.
[0044]
Here, the operation when the uninterruptible power supply apparatus uses the sum of the input voltage Vin from the external AC power supply 9 and the AC side voltage of the second AC / DC converter 2 as the output voltage Vout has been described.
[0045]
In order to keep the output voltage Vout constant, the second AC / DC converter 2 increases the voltage when the input voltage Vin is low, and decreases the voltage when the input voltage Vin is high.
[0046]
When the external AC power supply 9 fails, the switch 13 is opened, and the first AC / DC converter 1 converts the electric power of the storage battery 3 into AC and supplies it to the load 10.
[0047]
In the second embodiment, when the DC side current Iinv1dc and the DC side current Iinv2dc are detected, the instantaneous powers of the first AC / DC converter 1 and the second AC / DC converter 2 when Vdc = 1 are detected. . When the AC side voltage command value Iinv1ac_ref is controlled so that the sum of the charging current command value Ibatt_ref and the DC side current Iinv2dc becomes equal to the DC side current Iinv1dc, the first AC / DC converter 1 causes the instantaneous charging power of the storage battery 3 and the second AC / DC The instantaneous output power of the converter 2 can be supplied.
[0048]
Since the low-pass filters 161 and 162 cut high-order harmonic components, the first AC / DC converter 1 need only supply the low-order harmonic components output by the second AC / DC converter 2. . Although higher-order harmonics flow through the DC capacitor 6, the ripple tolerance can be reduced as compared with the lower-order harmonics.
[0049]
In addition, the sum of the input voltage Vin and the AC side voltage of the second AC / DC converter 2 is output, and the voltage is stepped up or down according to the magnitude of the input voltage Vin, so that a stable voltage can be supplied to the load 10.
[0050]
Example 3
FIG. 4 is a block diagram showing a system configuration of Embodiment 3 of the uninterruptible power supply according to the present invention. The AC side of the first AC / DC converter 1 is connected in parallel to the output end via the transformer 4 having a turns ratio of 1: n1, and the filter capacitor 7 is also connected in parallel to the output end. A load 10 is connected to the output end.
[0051]
AC power is introduced through the switch 13 from the input end to which the external AC power source 9 is connected. The AC side of the second AC / DC converter 2 is connected in series between the input end and the output end via the transformer 5 having a turns ratio of 1: n2. A filter capacitor 8 is connected in parallel with the transformer 5.
[0052]
The DC side of the first AC / DC converter 1 and the second AC / DC converter 2 is connected in parallel to the storage battery 3 and the DC capacitor 6.
[0053]
The detector 111 detects the AC side current Iinv1ac of the first AC / DC converter 1. The detector 112 detects the direct current on the second AC / DC converter 2. The detector 114 detects the output voltage Vout. The detector 115 detects a DC voltage Vdc. The low-pass filter 161 outputs Iinv2dc obtained by cutting high-order harmonic components from the direct current.
[0054]
The command value output means 121 outputs a command value Ibatt_ref of the charging current corresponding to the DC voltage Vdc.
[0055]
The positive / negative polarity determining means 123 outputs the positive / negative polarity of the output voltage Vout. When the output voltage Vout is positive, 1 is output, and when it is negative, -1 is output.
[0056]
When the sum of the charging current command value Ibatt_ref and the DC side current Iinv2dc is multiplied by the output of the positive / negative polarity determining means 123, the AC side current command value Iinv1ac_ref of the first AC / DC converter 1 is obtained. The computing means 128 obtains the ratio between the output voltage Vout and the DC voltage Vdc. That is, in order to convert the number of turns of the transformer 4, | Vout | / (n1 · Vdc) is calculated and output. The control unit 124 controls the first AC / DC converter 1 so that the value obtained by multiplying the AC side current Iinv1ac by the output of the calculation unit 128 follows the AC side current command value Iinvac_ref.
[0057]
The reference value output means 125 outputs the output voltage reference value Vout_ref. The command value output means 126 outputs the AC side voltage command value V2ac_ref of the second AC / DC converter 2 so that the output voltage Vout becomes the output voltage reference value Vout_ref. The control means 127 controls the second AC / DC converter 2 based on the AC side voltage command value V2ac_ref.
[0058]
Here, the operation when the uninterruptible power supply apparatus uses the sum of the input voltage Vin from the external AC power supply 9 and the AC side voltage of the second AC / DC converter 2 as the output voltage Vout has been described.
[0059]
In order to keep the output voltage Vout constant, the second AC / DC converter 2 increases the voltage when the input voltage Vin is low, and decreases the voltage when the input voltage Vin is high.
[0060]
When the external AC power supply 9 fails, the switch 13 is opened, and the first AC / DC converter 1 converts the electric power of the storage battery 3 into AC and supplies it to the load 10.
[0061]
In the third embodiment, when the DC side current Iinv2dc is detected, the instantaneous power of the second AC / DC converter 2 when Vdc = 1 is detected. Further, the instantaneous power is estimated when the DC voltage Vdc of the first AC / DC converter 1 is set to 1 by multiplying the AC side current Iinv1ac by the ratio of the output voltage Vout and the DC voltage Vdc. Since the estimated instantaneous power of the first AC / DC converter 1 is made to follow the AC side voltage command value Iinv1ac_ref, the first AC / DC converter 1 calculates the instantaneous charging power of the storage battery 3 and the instantaneous output power of the second AC / DC converter 2. Can supply.
[0062]
Since the low-pass filter 161 cuts high-order harmonic components, the first AC / DC converter 1 needs to supply only the low-order harmonic components output by the second AC / DC converter 2. Although higher-order harmonics flow through the DC capacitor 6, the ripple tolerance can be reduced as compared with the lower-order harmonics.
[0063]
In addition, the sum of the input voltage Vin and the AC side voltage of the second AC / DC converter 2 is output, and the voltage is stepped up or down according to the magnitude of the input voltage Vin, so that a stable voltage can be supplied to the load 10.
[0064]
Example 4
FIG. 5 is a block diagram showing a system configuration of embodiment 4 of the uninterruptible power supply according to the present invention. The AC side of the first AC / DC converter 1 is connected in parallel to the output end via the transformer 4 having a turns ratio of 1: n1, and the filter capacitor 7 is also connected in parallel to the output end. A load 10 is connected to the output end.
[0065]
The DC side of the first AC / DC converter 1 and the second AC / DC converter 2 is connected in parallel to the storage battery 3 and the DC capacitor 6.
[0066]
AC power is introduced through the switch 13 from the input end to which the external AC power source 9 is connected. The AC side of the second AC / DC converter 2 is connected in series between the input end and the output end via the transformer 5 having a turns ratio of 1: n2. A filter capacitor 8 is connected in parallel with the transformer 5.
[0067]
The detector 111 detects the AC side current Iinv1ac of the first AC / DC converter 1. The detector 114 detects the output voltage Vout. The detector 115 detects a DC voltage Vdc. The detector 117 detects the AC side current Iinv2ac of the second AC / DC converter 2. The detector 118 detects the AC side voltage V2ac of the second AC / DC converter 2.
[0068]
The command value output means 121 outputs a command value Ibatt_ref of the charging current corresponding to the DC voltage Vdc. The calculating means 129 calculates the ratio between the AC side voltage V2ac and the DC voltage Vdc of the second AC / DC converter 2. That is, V2ac / (n2 · Vdc) is calculated and output.
[0069]
When the AC side current Iinv2ac is multiplied by the output of the calculation means 129, the DC side current of the second AC / DC converter 2 is equivalently passed through a low-pass filter.
[0070]
The positive / negative polarity determining means 123 outputs the positive / negative polarity of the output voltage Vout. When the output voltage Vout is positive, 1 is output, and when it is negative, -1 is output.
[0071]
When the output of the positive / negative polarity judging means 123 is multiplied by the sum of the value obtained by multiplying the AC side current Iinv2ac by the output of the computing means 129 and the charging current command value Ibatt_ref, the AC side current command value Iinv1ac_ref of the first AC / DC converter 1 is obtained. Become. The computing means 128 obtains the ratio between the output voltage Vout and the DC voltage Vdc. That is, in order to convert the number of turns of the transformer 7, | Vout | / (n1 · Vdc) is calculated and output. The control unit 124 controls the first AC / DC converter 1 so that the value obtained by multiplying the AC side current Iinv1ac by the output of the calculation unit 128 follows the AC side current command value Iinvac_ref.
[0072]
The reference value output means 125 outputs the output voltage reference value Vout_ref. The command value output means 126 outputs the AC side voltage command value V2ac_ref of the second AC / DC converter 2 so that the output voltage Vout becomes the output voltage reference value Vout_ref. The control means 127 controls the second AC / DC converter 2 based on the AC side voltage command value V2ac_ref.
[0073]
Here, the operation when the uninterruptible power supply apparatus uses the sum of the input voltage Vin from the external AC power supply 9 and the AC side voltage of the second AC / DC converter 2 as the output voltage Vout has been described.
[0074]
In order to keep the output voltage Vout constant, the second AC / DC converter 2 increases the voltage when the input voltage Vin is low, and decreases the voltage when the input voltage Vin is high.
[0075]
When the external AC power supply 9 fails, the switch 13 is opened, and the first AC / DC converter 1 converts the electric power of the storage battery 3 into AC and supplies it to the load 10.
[0076]
The fourth embodiment is different from the third embodiment in which the detection target is the DC side current Iinv2dc of the second AC / DC converter 2, but is different in that the AC side current Iinv2ac of the second AC / DC converter 2 is detected. The same effect as 3 is obtained.
[0077]
Example 5
FIG. 6 is a block diagram showing a system configuration of embodiment 5 of the uninterruptible power supply according to the present invention. The AC side of the first AC / DC converter 1 is connected in parallel to the output end via the transformer 4 having a turns ratio of 1: n1, and the filter capacitor 7 is also connected in parallel to the output end. A load 10 is connected to the output end.
[0078]
AC power is introduced through the switch 13 from the input end to which the external AC power source 9 is connected. The AC side of the second AC / DC converter 2 is connected in series between the input end and the output end via the transformer 5 having a turns ratio of 1: n2. A filter capacitor 8 is connected in parallel with the transformer 5.
[0079]
The DC side of the first AC / DC converter 1 and the second AC / DC converter 2 is connected in parallel to the storage battery 3 and the DC capacitor 6.
[0080]
The detector 111 detects the AC side current Iinv1ac of the first AC / DC converter 1. The detector 114 detects the output voltage Vout. The detector 115 detects a DC voltage Vdc. The detector 117 detects the AC side current Iinv2ac of the second AC / DC converter 2.
[0081]
The command value output means 121 outputs a command value Ibatt_ref of the charging current corresponding to the DC voltage Vdc. The calculating means 129 calculates | requires ratio of the alternating current side voltage of the 2nd AC / DC converter 2, and DC voltage Vdc. Here, without detecting the AC side voltage of the second AC / DC converter 2, the number of turns of the transformer 8 is converted using the command value, and V2ac_ref / (n2 · Vdc) is calculated and output. When the AC side current Iinv2ac is multiplied by the output of the computing means 129, the DC side current of the second AC / DC converter 2 is equivalently passed through a low-pass filter.
[0082]
The positive / negative polarity determining means 123 outputs the positive / negative polarity of the output voltage Vout. When the output voltage Vout is positive, 1 is output, and when it is negative, -1 is output.
[0083]
When the sum of the value obtained by multiplying the AC side current Iinv2ac by the output of the computing means 129 and the charging current command value Ibatt_ref is multiplied by the output of the positive / negative polarity determining means 123, the AC side current command value Iinv1ac_ref of the first AC / DC converter 1 is obtained. Become. The computing means 128 obtains the ratio between the output voltage Vout and the DC voltage Vdc. In order to convert the number of turns of the transformer 7, | Vout | / (n1 · Vdc) is calculated and output. The control unit 124 controls the first AC / DC converter 1 so that a value obtained by multiplying the AC side current Iinv1ac by the output of the calculation unit 128 follows the AC side current command value Iinvac_ref.
[0084]
The reference value output means 125 outputs the output voltage reference value Vout_ref. The command value output means 126 outputs the AC side voltage command value V2ac_ref of the second AC / DC converter 2 so that the output voltage Vout becomes the output voltage reference value Vout_ref. The second AC / DC converter control means 127 controls the second AC / DC converter 2 based on the AC side voltage command value V2ac_ref.
[0085]
Here, the operation when the uninterruptible power supply outputs the sum of the input voltage Vin from the external AC power supply 9 and the AC side voltage of the second AC / DC converter 2 has been described.
[0086]
In order to make the output voltage Vout constant, the second AC / DC converter 2 increases the voltage when the input voltage Vin is low, and decreases the voltage when the input voltage Vin is high.
[0087]
When the external AC power supply 9 fails, the switch 13 is opened, and the first AC / DC converter 1 converts the power of the storage battery 3 into AC and supplies it to the load 10.
[0088]
The fifth embodiment is different from the third embodiment that is the AC side voltage of the second AC / DC converter 2 in that the DC side voltage of the second AC / DC converter 2 is detected, but the same effect as the third embodiment. Is obtained. The third embodiment is different from the third embodiment in which the object to be detected is the DC side current Iinv2dc of the second AC / DC converter 2, but is different in that the AC side current Iinv1ac of the first AC / DC converter 1 is detected. can get.
[0089]
<< Example 1 of the first AC / DC converter 1 >>
FIG. 7 is a diagram showing a circuit configuration of the first embodiment of the first AC / DC converter 1 and the first AC / DC converter control means 124 in each embodiment of the present invention. The first AC / DC converter 1 has a full bridge configuration using power MOSFETs 101 to 104. The proportional-plus-integral calculator 1241 performs a proportional-integral calculation on the error between the AC-side current command value Iinv1ac_ref and the AC-side current Iinv1ac. The sawtooth wave generation circuits 1242 and 1243 each have a predetermined carrier frequency and output a waveform that varies between 0 and 1 and -1 to 0. The comparator 1244 outputs 1 when (output of 1241) ≧ (output of 1242), and outputs 0 when (output of 1241) <(output of 1242). The comparator 1245 outputs 1 when (output of 1241) <(output of 1243), and outputs 0 when (output of 1241) ≧ (output of 1243). Gate drive circuits 12461 to 12464 drive 101 to 104, respectively. When the input is positive, the power MOSFET is turned on. When the input is negative, the power MOSFET is turned off.
[0090]
<< Embodiment 2 of the first AC / DC converter 1 >>
FIG. 8 is a diagram showing a circuit configuration of the second embodiment of the first AC / DC converter 1 and the first AC / DC converter control means 124 in each embodiment of the present invention. The first AC / DC converter 1 has a full bridge configuration using power MOSFETs 101 to 104. The comparator 1247 is a comparator with hysteresis. That is, 1 and 0 are output by the change in the magnitude relationship between the AC side current command value Iin1vac_ref and the AC side current Iinv1ac. The polarity determination circuit 1248 determines the polarity of the output voltage Vout. When the output voltage Vout is positive, 1 is output, and when it is negative, 0 is output. Gate drive circuits 12461 to 12464 drive power MOSFETs 101 to 104, respectively. When the input is positive, the power MOSFET is turned on. When the input is negative, the power MOSFET is turned off.
[0091]
<< Example of Second AC / DC Converter 2 >>
FIG. 9 is a diagram showing a specific example of the circuit configuration and control circuit of the second AC / DC converter 2 in each embodiment of the present invention. The second AC / DC converter 2 has a full bridge configuration using power MOSFETs 201 to 204. The sawtooth wave generation circuits 1271 and 1272 output waveforms that change from 0 to 1 and −1 to 0 at predetermined carrier frequencies, respectively. The comparator 1273 outputs 1 when the AC side voltage command value V2ac_ref ≧ (1271 output) and outputs 0 when the AC side voltage command value V2ac_ref <(1271 output). The comparator 1274 outputs 1 when the AC side voltage command value V2ac_ref <(1272 output), and outputs 0 when the AC side voltage command value V2ac_ref ≧ (1272 output). Gate drive circuits 12751 to 12754 drive power MOSFETs 201 to 204, respectively. When the input is positive, the power MOSFET is turned on. When the input is negative, the power MOSFET is turned off.
【The invention's effect】
[0092]
According to the present invention, the means for detecting or estimating the instantaneous power of the first AC / DC converter and the second AC / DC converter, respectively, the sum of the input voltage from the external AC power source and the AC side voltage of the second AC / DC converter The first AC / DC converter is controlled so as to supply means for controlling the second AC / DC converter so that the voltage becomes a predetermined output voltage, and the instantaneous power output from the second AC / DC converter and the instantaneous charging power to the storage battery. Therefore, without connecting a storage battery discharge prevention reactor to the DC part or increasing the ripple resistance of the DC capacitor, power is supplied between the first AC / DC converter and the second AC / DC converter. An uninterruptible power supply that can supply and receive a specified voltage to the load, stably charge the storage battery, and eliminate the need for a battery discharge prevention reactor, reducing the overall size of the device and reducing costs. Location can be obtained.
[Brief description of the drawings]
[0093]
FIG. 1 is a block diagram showing a system configuration of embodiment 1 of an uninterruptible power supply according to the present invention.
FIG. 2 is a diagram showing a voltage / current waveform in the uninterruptible power supply shown in FIG. 1;
FIG. 3 is a block diagram showing a system configuration of embodiment 2 of the uninterruptible power supply according to the present invention.
FIG. 4 is a block diagram showing a system configuration of embodiment 3 of the uninterruptible power supply according to the present invention.
FIG. 5 is a block diagram showing a system configuration of embodiment 4 of the uninterruptible power supply according to the present invention.
FIG. 6 is a block diagram showing a system configuration of embodiment 5 of the uninterruptible power supply according to the present invention.
FIG. 7 is a diagram showing a circuit configuration of the first embodiment of the first AC / DC converter and the first AC / DC converter control means in each embodiment of the present invention.
FIG. 8 is a diagram showing a circuit configuration of a second embodiment of the first AC / DC converter and the first AC / DC converter control means in each embodiment of the present invention.
FIG. 9 is a diagram showing a circuit configuration of an embodiment of a second AC / DC converter and second AC / DC converter control means in each embodiment of the present invention.
FIG. 10 is a block diagram showing a system configuration of an example of a conventional uninterruptible power supply.
11 is a diagram showing a voltage / current waveform in the conventional uninterruptible power supply shown in FIG.
[Explanation of symbols]
[0094]
1 1st AC / DC converter
2 Second AC / DC converter
3 storage battery
4 transformers
5 transformers
6 DC capacitor
7 Filter capacitors
8 Filter capacitors
9 AC power supply
10 Load
12 Control circuit
13 switch
14 Reactor for filter
15 Reactor for preventing battery discharge
101-104 Power MOSFET
110-119 Current and voltage detector
121 Storage battery charging current command value output means
122 operational amplifier
123 Positive / negative polarity judging means
124 1st AC / DC converter control means
1241 Proportional integral calculator
1242 sawtooth generator
1243 sawtooth generator
1244 Comparator
1245 comparator
12461-12464 gate drive circuit
1247 Comparator with hysteresis
1248 Input positive / negative polarity judging means
125 Output voltage reference value output means
126 AC side voltage command value control means
127 Second AC / DC converter control means
1271 sawtooth wave generator
1272 Sawtooth Wave Generator
1273 comparator
1274 comparator
12751-12754 gate drive circuit
128 Divider
129 Divider
161 Low-pass filter
162 Low-pass filter
201-204 Power MOSFET

Claims

AC power is introduced from an external AC power source connected to the input end, the AC side of the first AC / DC converter is connected in parallel to the output end, and the AC side of the second AC / DC converter is connected between the input end and the output end. Are connected in series, and DC power storage means and a DC capacitor are connected in parallel to the DC side of the first AC / DC converter and the second AC / DC converter, and AC power is supplied to the load connected to the output terminal in normal times. And the DC power storage means is charged, and the first AC / DC converter converts the DC power of the DC power storage means into AC power and supplies it to the load at the time of a power failure of the external AC power supply. In
Means for detecting an AC side current of the first AC / DC converter, means for detecting a DC side current of the second AC / DC converter, means for detecting a charging current and a DC voltage of the DC power storage means, Means for detecting the output voltage of the uninterruptible power supply, and means for removing higher-order harmonic components of the DC-side current detection value of the second AC / DC converter,
Means for controlling the second AC / DC converter so that the sum of the input voltage from the external AC power source and the AC side voltage of the second AC / DC converter becomes a predetermined output voltage;
A command value of the charging current is calculated according to the detected value of the DC voltage, and an error component between the command value of the charging current and the detected value of the charging current and a DC-side current detected value of the second AC / DC converter are calculated. The first AC / DC conversion is performed by inverting the positive / negative depending on whether the detected value of the output voltage is positive or negative, and using the sum of the value obtained by removing higher-order harmonics as a command value of the AC side current of the first AC / DC converter An uninterruptible power supply comprising: means for causing the detected value of the AC side current of the battery to follow the command value.

AC power is introduced from an external AC power source connected to the input end, the AC side of the first AC / DC converter is connected in parallel to the output end, and the AC side of the second AC / DC converter is connected between the input end and the output end. Are connected in series, and DC power storage means and a DC capacitor are connected in parallel to the DC side of the first AC / DC converter and the second AC / DC converter, and AC power is supplied to the load connected to the output terminal in normal times. And the DC power storage means is charged, and the first AC / DC converter converts the DC power of the DC power storage means into AC power and supplies it to the load at the time of a power failure of the external AC power supply. In
Means for detecting the DC side current and AC side current of the first AC / DC converter, means for detecting the DC side current of the second AC / DC converter, means for detecting the DC voltage of the DC power storage means, The means for detecting the output voltage of the uninterruptible power supply, and the higher-order harmonic components of the DC side current detection value of the first AC / DC converter and the DC side current detection value of the second AC / DC converter are respectively removed. Means and
Means for controlling the second AC / DC converter so that the sum of the input voltage from the external AC power source and the AC side voltage of the second AC / DC converter becomes a predetermined output voltage;
A command value of the charging current corresponding to the detected value of the DC voltage is calculated, and a sum of values obtained by removing the higher harmonics of the command value of the charging current and the detected DC side current of the second AC / DC converter And the component of the difference between the detected value of the DC voltage of the first AC / DC converter and the value obtained by removing higher harmonics is inverted depending on whether the detected value of the output voltage is positive or negative, An uninterruptible power supply comprising: a command value for the AC side current of the AC / DC converter, and means for causing the detected value of the AC side current of the first AC / DC converter to follow the command value.

AC power is introduced from an external AC power source connected to the input end, the AC side of the first AC / DC converter is connected in parallel to the output end, and the AC side of the second AC / DC converter is connected between the input end and the output end. Are connected in series, and DC power storage means and a DC capacitor are connected in parallel to the DC side of the first AC / DC converter and the second AC / DC converter, and AC power is supplied to the load connected to the output terminal in normal times. And the DC power storage means is charged, and the first AC / DC converter converts the DC power of the DC power storage means into AC power and supplies it to the load at the time of a power failure of the external AC power supply. In
Means for detecting an AC side current of the first AC / DC converter, means for detecting a DC side current of the second AC / DC converter, means for detecting a DC voltage of the DC power storage means, and the uninterruptible power supply Means for detecting the output voltage of the device, and means for removing higher-order harmonic components of the DC-side current detection value of the second AC / DC converter,
Means for controlling the second AC / DC converter so that the sum of the input voltage from the external AC power source and the AC side voltage of the second AC / DC converter becomes a predetermined output voltage;
The charge current command value corresponding to the detected value of the DC voltage is calculated, and the charge current command value and a value obtained by removing higher-order harmonics of the detected value of the DC side current of the second AC / DC converter; Is inverted depending on whether the detected value of the output voltage is positive or negative, and is used as a command value for the AC side current of the first AC / DC converter, and the detected value of the AC side current of the first AC / DC converter is An uninterruptible power supply comprising: means for causing a value obtained by multiplying a ratio between a detected value of the output voltage and a detected value of the DC voltage to follow a command value of the AC side current of the first AC / DC converter .

AC power is introduced from an external AC power source connected to the input end, the AC side of the first AC / DC converter is connected in parallel to the output end, and the AC side of the second AC / DC converter is connected between the input end and the output end. Are connected in series, and DC power storage means and a DC capacitor are connected in parallel to the DC side of the first AC / DC converter and the second AC / DC converter, and AC power is supplied to the load connected to the output terminal in normal times. And the DC power storage means is charged, and the first AC / DC converter converts the DC power of the DC power storage means into AC power and supplies it to the load at the time of a power failure of the external AC power supply. In
Means for detecting the AC side current of the first AC / DC converter, means for detecting the AC side current and voltage of the second AC / DC converter, means for detecting the DC voltage of the DC power storage means, Means for detecting the output voltage of the power failure power supply,
Means for controlling the second AC / DC converter so that the sum of the input voltage from the external AC power source and the AC side voltage of the second AC / DC converter becomes a predetermined output voltage;
A command value of the charging current according to the detected value of the DC voltage is calculated, and the detected value of the AC side voltage of the second AC / DC converter and the DC voltage are detected as the detected value of the AC side current of the second AC / DC converter. To the detected value of the DC side current of the second AC / DC converter, and the sum of the charging current command value and the detected value of the DC side current of the second AC / DC converter is output. Depending on whether the detection value of the voltage is positive or negative, the positive / negative is inverted to obtain a command value of the AC side current of the first AC / DC converter, and the detection value of the output voltage is detected as the AC side current detection value of the first AC / DC converter And a means for causing a value obtained by multiplying a ratio of the detected value of the DC voltage to a command value of the AC side current of the first AC / DC converter.

AC power is introduced from an external AC power source connected to the input end, the AC side of the first AC / DC converter is connected in parallel to the output end, and the AC side of the second AC / DC converter is connected between the input end and the output end. Are connected in series, and DC power storage means and a DC capacitor are connected in parallel to the DC side of the first AC / DC converter and the second AC / DC converter, and AC power is supplied to the load connected to the output terminal in normal times. And the DC power storage means is charged, and the first AC / DC converter converts the DC power of the DC power storage means into AC power and supplies it to the load at the time of a power failure of the external AC power supply. In
Means for detecting an AC side current of the first AC / DC converter, means for detecting an AC side current of the second AC / DC converter, means for detecting a DC voltage of the DC power storage means, and the uninterruptible power supply Means for detecting the output voltage of the device,
Means for controlling the second AC / DC converter so that the sum of the input voltage from the external AC power source and the AC side voltage of the second AC / DC converter becomes a predetermined output voltage;
A command value of the charging current according to the detected value of the DC voltage is calculated, and the command value of the AC side voltage of the second AC / DC converter and the DC voltage are added to the detected value of the AC side current of the second AC / DC converter. To the detected value of the DC side current of the second AC / DC converter, and the sum of the charging current command value and the detected value of the DC side current of the second AC / DC converter is output. Depending on whether the detection value of the voltage is positive or negative, the positive / negative is inverted to obtain a command value of the AC side current of the first AC / DC converter, and the detection value of the output voltage is detected as the AC side current detection value of the first AC / DC converter And a means for causing a value obtained by multiplying a ratio of the detected value of the DC voltage to a command value of the AC side current of the first AC / DC converter.