JP2004064904A

JP2004064904A - Power supply device and motor control device using the same

Info

Publication number: JP2004064904A
Application number: JP2002220591A
Authority: JP
Inventors: Yasuo Notohara; 能登原　保夫; Hisanori Suzuki; 鈴木　尚礼; Tsunehiro Endo; 遠藤　常博; Junichi Takagi; 高木　純一
Original assignee: Hitachi Ltd; Hitachi Home and Life Solutions Inc
Current assignee: Hitachi Ltd; Hitachi Appliances Inc
Priority date: 2002-07-30
Filing date: 2002-07-30
Publication date: 2004-02-26
Anticipated expiration: 2022-07-30
Also published as: JP3806678B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply device that detects the abnormality of an AC power supply and stops a short-circuit operation. <P>SOLUTION: An input cycle of a zero cross signal from a zero cross detection circuit that detects the zero cross point of the AC power supply is measured, the circuit operation of a short-circuit circuit is stopped when the input cycle reaches a prescribed value or is out of a prescribed range, and also the short-circuit operation of the short-circuit circuit is stopped when the input cycle of the input signal of the zero cross signal is changed, or when the input signal of the zero cross signal is not inputted for a prescribed time. Furthermore, the short-circuit operation of the circuit for short-circuiting is stopped when the zero cross signal is not inputted during a range from the input time of the zero cross signal to a second prescribed time after a first prescribed time. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は交流電力を直流電力に変換する電源装置に係り、特に交流電源半周期に一回もしくは複数回の短絡動作で電源電流波形を正弦波状に制御して力率改善を行う電源装置に関する。
【０００２】
【従来の技術】
交流電源の電源半周期に一回の短絡動作を行って入力電流波形を正弦波状に制御し力率改善を行う電源装置が、特開２００２−１０１５５０号公報に開示されている。特開２００２−１０１５５０号公報には力率改善方法と、全波整流回路と倍電圧整流回路を切り替える回路構成の電源装置が記載されていて、前記電源装置の過電圧や過電流時の保護動作が記載されている。
【０００３】
前記従来技術では、整流回路出力側の直流電流や短絡回路の電流の値が所定値を超えたら短絡動作を停止し、短絡回路を過電流から保護し、同時に整流回路構成を全波整流回路に切り替え、空調機用モータ制御装置などのシステムを初期状態に戻す処理を記載している。
【０００４】
【発明が解決しようとする課題】
前記特開２００２−１０１５５０号公報に記載の従来技術では、交流電源の異常時のように電源周期が検出できない場合の保護方法や、交流電源の異常検出方法については記載がない。言い換えると、前記従来技術のように交流電源の電源周期（零クロス信号）に同期して短絡回路の短絡動作を行う力率改善方法では、交流電源の電源周期（零クロス信号）が正しく得られていることを前提にしているために、誤った電源周期（零クロス信号）を基に短絡動作を行うと過電流や短絡回路の破壊等の不都合を招く。
【０００５】
一般的に過電流時の保護は速い動作が要求されるため、過電流検出回路も瞬時に動作する設定となっている。このため、外来ノイズ等の影響を受けやすく誤検出する可能性が大きい。しかし、前記従来技術では、過電流検出回路の誤検出時の誤動作防止については考慮されていない。
【０００６】
さらに、前記従来技術では過電流保護動作を行うと同時に空調機用モータ制御装置などのシステムを初期状態に戻しているが、過電流保護動作が動作するたびに初期状態に戻っていてはシステムの動作を継続できない。空調機用モータ制御装置を例に説明すると、いったん過電流保護動作が動作すると、モータ制御装置はモータを停止（初期状態に設定）させ再度起動を行うが、空調機の圧縮機駆動用モータ制御装置では圧縮機の負荷（圧力）をバランスさせるため３分間停止する。このため、空調機は３分間仕事をしないことになり、使用者に不快感を与える。
【０００７】
本発明の目的は交流電源の異常を検出し短絡動作を停止する電源装置を提供することである。
【０００８】
【課題を解決するための手段】
本発明の電源装置は、交流電源の異常を正しく検出する。交流電源の異常には瞬停，停電，周波数変動，電圧変動がある。さらに、日本の場合、商用交流電源の周波数は５０Ｈｚと６０Ｈｚとがあるので、電源周波数の検出と自動認識（設定）も必要である。
【０００９】
本発明の電源装置は、交流電源の零クロス点を検出する零クロス検出回路からの零クロス信号の入力周期を測定し入力周期が所定値、例えば６０Ｈｚ電源の場合８．３３３ｍｓ　、５０Ｈｚ電源の場合１０ｍｓ、もしくは所定の範囲、例えば６０Ｈｚ電源の場合８．３ｍｓ　から８．３６ｍｓ　、５０Ｈｚ電源の場合９．９６ｍｓから１０．０４ｍｓ以外の場合に短絡回路の短絡動作を停止する。
【００１０】
本発明の電源装置は、零クロス信号の入力信号の入力周期が変化したときに短絡回路の短絡動作を停止する。
【００１１】
本発明の電源装置は、零クロス信号の入力信号が所定の時間入力されないときに短絡回路の短絡動作を停止する。
【００１２】
本発明の電源装置は、零クロス信号の入力時点から第１の所定時間以降第２の所定時間までの範囲に零クロス信号の入力がない時に短絡回路の短絡動作を停止する。
【００１３】
本発明の電源装置は、零クロス信号の入力時点から所定の時間だけ次の零クロス信号の入力を受け付けない。
【００１４】
本発明の電源装置は、零クロス信号の入力時点から第１の所定時間以降第２の所定時間までの範囲に前記零クロス信号の入力が無いと、零クロス信号が異常であると判断し零クロス信号を受け付けない。
【００１５】
本発明の電源装置は、検出した零クロス信号の入力周期から所定値もしくは所定の範囲を決定することにより自動的に電源の周期（周波数）を設定できる。
【００１６】
本発明の電源装置は、電源に異常があるときには短絡回路の短絡動作を速やかに停止し、交流電源の異常による誤動作を防止できる。
【００１７】
本発明の電源装置は、短絡回路が短絡している期間にのみ過電流検出信号を受け付け、システム停止を含む過電流保護動作を行う。
【００１８】
本発明の電源装置は、前記保護動作の動作時間を積算もしくは動作回数をカウントし、その値が所定値に達したところでシステムを停止もしくはシステムに異常信号を出力する。また、本発明の電源装置は、前記カウントを保護動作が連続的に続いた期間もしくは回数として、システムの停止頻度を最小限に抑える。
【００１９】
【発明の実施の形態】
以下、本発明の電源装置について、図面を用いて詳しく説明する。各図面の同じ符号は同じ構成要素を示す。
【００２０】
本実施例の電源装置は、交流電源の電源半周期に１回もしくは複数回リアクトルを介して交流電源を短絡し、電源の力率を改善する。図１に本実施例の電源装置１３を示す。図１は、電源装置１３のインバータ回路７に空調機圧縮機駆動用のモータ８を接続した空調機の圧縮機駆動用モータの制御装置の場合の回路構成を示す。
【００２１】
図１に示す本実施例の電源装置１３は交流電源１の一方の端子に接続されたリアクトル２と、リアクトル２を介して交流電源１を短絡するように接続した短絡回路３と、リアクトル２を介して接続している、交流を直流に変換する整流回路４と、整流回路４を全波整流回路構成と倍電圧整流回路構成とに切替える切替スイッチ５と、平滑回路６とを備えており、短絡回路３と切替スイッチ５は、制御回路９が出力する短絡信号３Ｓと切替信号５Ｓとによって動作する。
【００２２】
図１に示すように、制御回路９には、交流電源１の電圧がゼロになる零クロス点を検出する零クロス検出回路１０が出力する零クロス信号１０Ｓと、電源装置１３に流入する電流を検出する入力電流検出回路１１が出力する入力電流値１１Ｓとが入力される。前記各信号は短絡回路３と、切替スイッチ５とを制御するために使用する。
【００２３】
短絡回路３は双方向に電流が流せる双方向スイッチであり、本実施例ではダイオードブリッジ回路と、ＩＧＢＴやパワーＭＯＳＦＥＴなどの電力半導体スイッチング素子とを備えている。切替スイッチ５も短絡回路３と同様に双方向スイッチであり、本実施例ではパワーリレーである。平滑回路６は図１に示すように平滑コンデンサを直列接続しており、中間点が切替スイッチ５に接続していて、切替スイッチ５で全波整流回路構成と倍電圧整流回路構成とに切り替える。
【００２４】
モータ８の回転数制御は制御回路９内のソフトウエア処理で行い、ＰＷＭ信号７Ｓでインバータ回路７を駆動する。本実施例ではモータ制御の方法についての詳細な説明は省略するが、インバータ回路７に流入する直流電流を抵抗１２Ａと直流電流検出回路１２とで検出し、その出力である直流電流値１２Ｓを制御回路９に入力してモータ８に流れるモータ電流を再現し、そのモータ電流情報を基にベクトル制御を行って、モータの回転数とトルクとを制御する。
【００２５】
次に図２と、図３とを用いて本実施例の電源回路の力率改善動作と短絡信号の発生方法を説明する。図２は交流電源１の電源電圧と入力電流と、零クロス信号１０Ｓと、短絡信号３Ｓとの時間変化を示した波形図である。以下、本実施例では電源周波数の半周期に一回短絡動作を行う場合を説明するが、電源周波数の半周期に複数回短絡動作をする場合も同様である。
【００２６】
図２に示すように零クロス信号１０Ｓは、電源電圧の零点で「Ｈ」と「Ｌ」とが反転する矩形波信号であり、信号が反転するエッジ部分が零クロス点である。短絡信号３Ｓは、零クロス信号１０Ｓのエッジ部分を基準にディレイ時間Ｔｄ，パルス幅Ｔｐとなるパルスである。ここで、ディレイ時間Ｔｄとは零クロス点（基準点）から短絡動作を開始するまでの時間、パルス幅Ｔｐとは短絡している時間を示す。短絡信号３Ｓで短絡回路３を動作させると、図２に示すように電源装置１３の入力電流の通流幅が増加するので力率が向上する。
【００２７】
本実施例の制御回路９は市販のシングルチップマイクロコンピュータ（以下マイコンと呼ぶ）を用い、全ての処理をソフトウエアで処理した。図３に、零クロス信号１０Ｓと、前記マイコン内のフリーランタイマの値と、このフリーランタイマ値と逐次比較を行い一致した時に割込を発生するアウトプットコンペアマッチレジスタ（以下ＯＰレジスタと呼ぶ）の値と、短絡信号３Ｓとを時系列に示す。
【００２８】
時刻Ｔ０で零クロス信号１０Ｓが反転すると、第１の割込処理によりＯＰレジスタにディレイ時間ＴｄのデータＤ０が書き込まれる。時刻Ｔ１でフリーランタイマの値とＯＰレジスタの値とが一致して第２の割込処理が起動され、短絡信号３Ｓを「Ｈ」出力すると同時に前記ＯＰレジスタにパルス幅ＴｐのデータＤ１が書き込まれる。
【００２９】
時刻Ｔ２では再度フリーランタイマの値とＯＰレジスタの値とが一致して第３の割込処理が起動され短絡信号３Ｓを「Ｌ」出力にする。この後は、再度零クロス信号１０Ｓの反転が発生するまで短絡信号３Ｓは「Ｌ」出力を維持する。ここで、短絡信号３Ｓは「Ｈ」が短絡、「Ｌ」が開放を意味する。前記動作を零クロス信号１０Ｓが入力（反転）する度に繰り返して電源周波数の半周期毎に所定の短絡動作を続ける。
【００３０】
本実施例の電源装置１３が交流電源１の異常を検出し、短絡動作を停止する保護方法を説明する。図４は、交流電源１の電源電圧波形と電源電圧から作成される零クロス信号１０Ｓと、零クロス信号１０Ｓの入力に応じて動作する割込処理の動作を禁止する割込マスク信号とを示し、瞬停や重畳ノイズなどで電圧歪みが生じて零クロス信号１０Ｓにチャタリングが発生した場合を示す。図４に示すように零クロス信号１０Ｓがチャタリングを起こすと、割込処理が続けて起動され所定のタイミングの短絡動作ができなくなり過電流等を発生するおそれがある。
【００３１】
そこで、図４に示すように、零クロス信号１０Ｓの入力（反転）後の一定時間、零クロス信号に伴う割込処理を実行しない、言い換えると、割込マスク時間Ｔｍの間、零クロス信号１０Ｓを受け付けない割込マスク信号を発生する。割込マスク信号処理により、電源環境が悪くても零クロス信号の誤検出による短絡動作の誤動作を無くし、過電流発生やシステム停止を予防し、正規の動作を維持できる。なお、零クロス検出回路１０の出力特性が悪く零クロス信号１０Ｓがチャタリングを起こす回路構成である場合にも前記割込マスク信号処理が有効である。
【００３２】
図５を用いて、零クロス信号１０Ｓが所定の周期で正しく制御回路９に入力されているかどうかを監視する方法を説明する。日本国内では、商用交流電源の電源周波数は５０Ｈｚと６０Ｈｚであるが、この周波数が極端に変動することは皆無である。本実施例では、瞬停や雷サージ等により零クロス信号１０Ｓが所定の周期以外で発生した場合の誤動作を主に防止する。
【００３３】
商用交流電源の電源周波数は安定しているので、いったん電源周波数が検出できれば、その後は決まった周期で零クロス信号１０Ｓが入力されるはずである。そこで、零クロス信号１０Ｓが入力された図５のＡ点から次に零クロス信号１０Ｓが入力されるＣ点までの周期（時間）を測り、その周期が電源周波数の周期もしくはその付近の周期になっているかを確認し、そうでない場合は短絡信号３Ｓを停止（「Ｌ」出力）にする。あるいは、零クロス信号１０Ｓが入力されたＡ点の時刻から次に零クロス信号１０Ｓが入力される予定のＣ点の時刻もしくはその付近の時刻（Ｂ点からＤ点）のみ前記零クロス信号１０Ｓの入力を受け付けてもよい。これらの方法によって、所定の周期もしくは時刻以外に入る誤った零クロス信号１０Ｓやノイズなどを排除できる。
【００３４】
図６に示すフローチャートを用いて零クロス信号１０Ｓの前記異常判定方法を説明する。図６（あ）のステップで図５のＡに示す零クロス信号１０Ｓの入力時刻Ａ点から、図５のＣに示す次回入力時刻Ｃ点までの時間間隔を測定し、ステップ（い）でその時間間隔（周期）が８．３３３ｍｓ（１／６０Ｈｚ／２（ｓ））、あるいは１０ｍｓ（１／５０Ｈｚ／２（ｓ））に一致、あるいは、実際には電源周波数は５０Ｈｚ，６０Ｈｚの何れの場合にも±０．２Ｈｚ　程度の変動があるのでその変動を含んだ８．３０ｍｓ〜８．３６ｍｓの範囲、あるいは９．９６ｍｓ〜１０．０４ｍｓ　の範囲になっているかどうかを判断する。Ｙｅｓであれば正常動作と判定してステップ（う），ステップ（え）へ進み、Ｎｏであれば異常動作と判定してステップ（お）に進み短絡動作を停止させる。ここで、ステップ（う）で測定した周期を用いて電源が５０Ｈｚか６０Ｈｚかを判断すれば自動的に電源周波数の検出ができる。
【００３５】
また、設置場所が固定されれば商用交流電源の電源周波数は固定されるので、動作中に電源周波数が変化することはないので、電源周期が変化すること自体が電源異常である。従って、動作中に前記測定周波数が変わった場合にも短絡動作を停止する。これにより、偶然比較値（周期）と同じようなタイミングで入力した誤信号による異常動作も予防できる。図７にこの場合のフローチャートを示す。
【００３６】
図８を用いて、零クロス信号１０Ｓが所定の周期で正しく入力されているかどうかを監視する方法を説明する。零クロス信号１０Ｓの入力時刻Ａ点から時刻Ｂ点までの期間と、時刻Ｄ点以降の期間には、零クロス信号１０Ｓ入力を受け付けないようにする。言い換えると、時刻Ｂ点から時刻Ｄ点の範囲のみ零クロス信号１０Ｓの入力を許可しそれ以外は許可しない。もしくは、零クロス信号１０Ｓの入力が許可された時間範囲に零クロス信号１０Ｓの入力がない場合は短絡動作を停止する。図８では電源周波数が５０Ｈｚの場合を例に、ある程度の周波数変動に対応できるように、時刻Ａ点から時刻Ｂ点までの時間幅Ｔ５５を電源周波数５５Ｈｚの半周期相当に設定、時刻Ａ点から時刻Ｄ点までの時間幅Ｔ４５を電源周波数４５Ｈｚの半周期相当に設定したものである。電源周波数がｆ（Ｈｚ）の場合には、前記のようにｆ±０．１ｆ　の範囲に図８の時刻Ａ点からの時間幅を決めればよい。
【００３７】
図９は零クロス信号１０Ｓと、短絡信号３Ｓと、零クロス信号１０Ｓの入力状態から短絡動作を許可／停止する短絡動作許可信号と、電源異常状態が連続的に続いたときに上位システムに異常を知らせる電源異常信号との関係をタイミングチャートに示す。図９は電源周波数５０Ｈｚで動作中に、時刻Ｔ２で停電が発生し時刻Ｔ２以降零クロス信号１０Ｓの入力がない状態を示す。
【００３８】
この場合、時刻Ｔ２までは正しく零クロス信号１０Ｓが入力されているので短絡信号３Ｓは出力されるが、時刻Ｔ３では零クロス信号１０Ｓが入力されないので短絡動作を停止する。その後時刻Ｔ５になっても零クロス信号１０Ｓが入力されない場合、引き続き短絡動作を停止すると同時に電源異常信号を上位システムに知らせる。本実施例では圧縮機を駆動するモータの運転を停止する。ここで、時刻Ｔ５とは最後の零クロス信号１０Ｓ入力時刻Ｔ２から予め設定されている時間Ｔｗ経過した時刻である。本実施例では電源周期の３倍に設定した場合を示す。これにより零クロス信号１０Ｓの入力が所定時間以上無いときに短絡動作を停止し、同時に上位システムに異常を知らせてシステムを停止できる。また、零クロス検出回路１０が故障した場合にも同様に動作するので、零クロス検出回路の異常判定に使用できる。
【００３９】
図１０を用いて過電流検出回路の誤検出に伴う過電流保護動作の誤動作防止方法を説明する。図１０は零クロス信号１０Ｓと、短絡信号３Ｓと、図１の入力電流検出回路１１内で検出する過電流検出信号と、マイコン内部で使用している過電流フラグと、過電流カウンタ（過電流保護動作回数をカウント）と、上位システムに知らせる過電流エラー信号との関係を示すタイミングチャートである。図１０は過電流信号に外来ノイズが重畳している状態を示し、「Ｆ」と示す信号が誤検出信号、「Ｔ」と示す信号が正規の過電流信号である。
【００４０】
図１０に示すように誤った過電流信号に反応して過電流保護動作を行うとシステムとして安定した制御ができない。そこで、短絡信号３Ｓが「Ｈ」、つまり短絡回路３が短絡中に入力される過電流信号のみに反応するように設定する。このように設定すると、図１０に示す過電流信号「Ｆ」入力時には過電流保護が動作せず、本当に過電流状態のときのみ保護動作がするので安定した制御ができる。ここで、過電流保護動作が実行されたときに図１０に示すようにマイコン内部の過電流フラグが「Ｈ」状態に変化する。
【００４１】
図１０では過電流保護動作を実行すると過電流フラグを「Ｈ」にする。その後、次の零クロス信号１０Ｓのエッジ入力時に過電流フラグが「Ｈ」であれば過電流カウンタを一つダウンカウントすると同時に前記過電流フラグをクリアする。過電流フラグが「Ｌ」の場合は、前記過電流カウンタを初期値に戻す。この動作を繰り返すことにより保護動作が連続的に実行される回数（もしくは時間）を計測する。過電流カウンタが０になったときに上位システムに過電流エラー信号を出力して異常を知らせる。本実施例では圧縮機を駆動するモータの運転を停止する。
【００４２】
以上により保護動作発生時の頻繁なシステムの停止を防止でき安定したシステムの動作ができる。また、本当にシステムを停止しなければならない異常時には確実にシステムを停止できる。なお、本保護動作は電源異常保護動作時にも適用できることは言うまでもない。
【００４３】
また、本実施例では前記で説明したすべての保護動作を常時行っており、安全性と安定性を確保している。本実施例の電源装置は、空調機や冷蔵庫の圧縮機のモータの駆動に好適である。
【００４４】
【発明の効果】
以上説明したように本発明の電源装置を用いれば、交流電源異常時の保護が容易にできる。また、外来ノイズ等の大きな環境でも保護動作の誤動作を防げ、システムの安定性に貢献できる。さらに、保護動作発生時の頻繁なシステムの停止を防止でき安定したシステムの動作ができる。
【図面の簡単な説明】
【図１】実施例のモータ制御装置の回路構成の説明図。
【図２】実施例の電源装置の力率改善と、短絡信号の発生方法の説明図。
【図３】実施例の電源装置の短絡信号作成方法の説明図。
【図４】実施例の電源装置の割込マスク信号の説明図。
【図５】実施例の電源装置の電源周期異常保護の説明図。
【図６】実施例の電源装置の零クロス信号異常判定フローチャート。
【図７】実施例の電源装置の零クロス信号異常判定の別の方法のフローチャート。
【図８】実施例の電源装置の電源周期保護の説明図。
【図９】実施例の電源装置の停電時保護の説明図。
【図１０】実施例の電源装置の過電流保護の説明図。
【符号の説明】
１…交流電源、２…リアクトル、３…短絡回路、４…整流回路、５…切替スイッチ、６…平滑回路、７…インバータ回路、８…モータ、９…制御回路、１０…零クロス検出回路、１１…入力電流検出回路、１２…直流電流検出回路、３Ｓ…短絡信号、５Ｓ…切替信号、６Ｓ…直流電圧値、７Ｓ…インバータＰＷＭ信号、１０Ｓ…零クロス信号、１１Ｓ…入力電流値、１２Ｓ…直流電流値。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a power supply device that converts AC power into DC power, and more particularly to a power supply device that controls a power supply current waveform in a sine wave shape by performing a short-circuit operation once or a plurality of times in a half cycle of an AC power supply to improve a power factor.
[0002]
[Prior art]
Japanese Unexamined Patent Application Publication No. 2002-101550 discloses a power supply device that performs a short-circuit operation once in a power supply half cycle of an AC power supply to control an input current waveform in a sine wave shape to improve a power factor. Japanese Unexamined Patent Application Publication No. 2002-101550 describes a power factor improving method and a power supply device having a circuit configuration for switching between a full-wave rectifier circuit and a voltage doubler rectifier circuit. Has been described.
[0003]
In the prior art, when the value of the DC current on the output side of the rectifier circuit or the current of the short circuit exceeds a predetermined value, the short circuit operation is stopped, the short circuit is protected from overcurrent, and at the same time, the rectifier circuit configuration is changed to a full-wave rectifier circuit. It describes a process of switching and returning a system such as an air conditioner motor control device to an initial state.
[0004]
[Problems to be solved by the invention]
In the prior art described in Japanese Patent Application Laid-Open No. 2002-101550, there is no description about a protection method when a power supply cycle cannot be detected, such as when an AC power supply is abnormal, or a method for detecting an AC power supply abnormality. In other words, in the power factor improving method of performing the short-circuit operation of the short circuit in synchronization with the power supply cycle (zero cross signal) of the AC power supply as in the above-described related art, the power supply cycle (zero cross signal) of the AC power supply can be obtained correctly. Therefore, if a short-circuit operation is performed based on an erroneous power supply cycle (zero cross signal), inconveniences such as overcurrent and breakage of a short-circuit will be caused.
[0005]
In general, protection against overcurrent requires a fast operation, so that the overcurrent detection circuit is set to operate instantaneously. For this reason, it is susceptible to external noise and the like, and the possibility of erroneous detection is high. However, the prior art does not take into consideration malfunction prevention at the time of erroneous detection of the overcurrent detection circuit.
[0006]
Further, in the above prior art, the system such as the air conditioner motor control device is returned to the initial state at the same time as performing the overcurrent protection operation. However, the system returns to the initial state every time the overcurrent protection operation is performed. Operation cannot be continued. Taking the motor control device for an air conditioner as an example, once the overcurrent protection operation is activated, the motor control device stops the motor (sets the motor to an initial state) and restarts the motor. The apparatus is stopped for 3 minutes to balance the load (pressure) of the compressor. For this reason, the air conditioner does not work for three minutes, which gives the user discomfort.
[0007]
An object of the present invention is to provide a power supply device that detects an abnormality of an AC power supply and stops a short circuit operation.
[0008]
[Means for Solving the Problems]
The power supply device of the present invention correctly detects an abnormality in the AC power supply. Abnormalities in AC power supply include instantaneous power failure, power failure, frequency fluctuation, and voltage fluctuation. Further, in the case of Japan, since the frequency of the commercial AC power supply is 50 Hz or 60 Hz, it is necessary to detect the power supply frequency and automatically recognize (set) it.
[0009]
The power supply device of the present invention measures the input cycle of a zero-cross signal from a zero-cross detection circuit that detects a zero-cross point of an AC power supply, and determines that the input cycle is a predetermined value, for example, 8.333 ms for a 60 Hz power supply, and 8.333 ms for a 50 Hz power supply. The short-circuit operation of the short-circuit circuit is stopped in a time period other than 10 ms or a predetermined range, for example, 8.3 ms to 8.36 ms for a 60 Hz power supply, and 9.96 ms to 10.04 ms for a 50 Hz power supply.
[0010]
The power supply device of the present invention stops the short circuit operation of the short circuit when the input cycle of the input signal of the zero cross signal changes.
[0011]
The power supply device of the present invention stops the short circuit operation of the short circuit when the input signal of the zero cross signal is not input for a predetermined time.
[0012]
The power supply device of the present invention stops the short-circuit operation of the short circuit when there is no input of the zero cross signal in a range from the first predetermined time to the second predetermined time from the input time of the zero cross signal.
[0013]
The power supply device of the present invention does not accept the input of the next zero cross signal for a predetermined time from the time of input of the zero cross signal.
[0014]
The power supply device according to the present invention determines that the zero-cross signal is abnormal if the zero-cross signal is not input within a range from the first predetermined time to the second predetermined time from the input time of the zero-cross signal, and determines that the zero-cross signal is abnormal. Does not accept cross signals.
[0015]
The power supply device of the present invention can automatically set the cycle (frequency) of the power supply by determining a predetermined value or a predetermined range from the input cycle of the detected zero cross signal.
[0016]
ADVANTAGE OF THE INVENTION The power supply device of this invention can stop the short circuit operation | movement of a short circuit immediately when there is abnormality in a power supply, and can prevent malfunction by abnormalities of AC power supply.
[0017]
The power supply device of the present invention receives an overcurrent detection signal only during a period in which the short circuit is short-circuited, and performs an overcurrent protection operation including a system stop.
[0018]
The power supply device of the present invention integrates the operation time of the protection operation or counts the number of operations, and stops the system when the value reaches a predetermined value or outputs an abnormal signal to the system. Further, the power supply device of the present invention minimizes the frequency of stopping the system by setting the count as a period or the number of times that the protection operation is continuously performed.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the power supply device of the present invention will be described in detail with reference to the drawings. The same reference numerals in the drawings indicate the same components.
[0020]
In the power supply device of the present embodiment, the AC power supply is short-circuited via the reactor once or plural times in a half cycle of the power supply of the AC power supply, thereby improving the power factor of the power supply. FIG. 1 shows a power supply device 13 of the present embodiment. FIG. 1 shows a circuit configuration of a control device for a compressor driving motor of an air conditioner in which an inverter circuit driving motor 8 is connected to an inverter circuit 7 of a power supply device 13.
[0021]
A power supply device 13 of the present embodiment shown in FIG. 1 includes a reactor 2 connected to one terminal of an AC power supply 1, a short circuit 3 connected to short-circuit the AC power supply 1 via the reactor 2, and a reactor 2 A rectifier circuit 4 for converting alternating current into direct current, a switch 5 for switching the rectifier circuit 4 between a full-wave rectifier circuit configuration and a voltage doubler rectifier circuit configuration, and a smoothing circuit 6, The short circuit 3 and the changeover switch 5 operate according to the short circuit signal 3S and the changeover signal 5S output from the control circuit 9.
[0022]
As shown in FIG. 1, the control circuit 9 includes a zero cross signal 10S output by a zero cross detection circuit 10 for detecting a zero cross point at which the voltage of the AC power supply 1 becomes zero, and a current flowing into the power supply device 13. The input current value 11S output from the input current detection circuit 11 to be detected is input. The signals are used to control the short circuit 3 and the changeover switch 5.
[0023]
The short circuit 3 is a bidirectional switch that allows current to flow in both directions. In this embodiment, the short circuit 3 includes a diode bridge circuit and a power semiconductor switching element such as an IGBT or a power MOSFET. The changeover switch 5 is also a bidirectional switch, like the short circuit 3, and is a power relay in this embodiment. As shown in FIG. 1, the smoothing circuit 6 has a smoothing capacitor connected in series, and an intermediate point is connected to the changeover switch 5, and the changeover switch 5 switches between a full-wave rectification circuit configuration and a voltage doubler rectification circuit configuration.
[0024]
The rotation speed of the motor 8 is controlled by software processing in the control circuit 9, and the inverter circuit 7 is driven by the PWM signal 7S. Although a detailed description of the motor control method is omitted in this embodiment, the DC current flowing into the inverter circuit 7 is detected by the resistor 12A and the DC current detection circuit 12, and the DC current value 12S that is the output thereof is controlled. The motor current flowing to the motor 8 is input to the circuit 9 to reproduce the motor current, and the vector control is performed based on the motor current information to control the rotation speed and torque of the motor.
[0025]
Next, a power factor improving operation and a method of generating a short-circuit signal of the power supply circuit according to the present embodiment will be described with reference to FIGS. FIG. 2 is a waveform diagram showing a time change of the power supply voltage and the input current of the AC power supply 1, the zero cross signal 10S, and the short circuit signal 3S. In the following, this embodiment describes a case where a short-circuit operation is performed once in a half cycle of the power supply frequency, but the same applies to a case where a short-circuit operation is performed a plurality of times in a half cycle of the power supply frequency.
[0026]
As shown in FIG. 2, the zero cross signal 10S is a rectangular wave signal in which “H” and “L” are inverted at the zero point of the power supply voltage, and the edge where the signal is inverted is the zero cross point. The short-circuit signal 3S is a pulse having a delay time Td and a pulse width Tp based on the edge portion of the zero cross signal 10S. Here, the delay time Td indicates the time from the zero crossing point (reference point) to the start of the short-circuit operation, and the pulse width Tp indicates the time of the short-circuit. When the short circuit 3 is operated by the short circuit signal 3S, as shown in FIG. 2, the flow width of the input current of the power supply device 13 is increased, so that the power factor is improved.
[0027]
The control circuit 9 of the present embodiment used a commercially available single-chip microcomputer (hereinafter referred to as a microcomputer), and all processes were performed by software. FIG. 3 shows an output compare match register (hereinafter referred to as an OP register) for generating an interrupt when the zero-cross signal 10S, the value of the free-run timer in the microcomputer, and the free-run timer value are successively compared and matched. And the short-circuit signal 3S are shown in chronological order.
[0028]
When the zero cross signal 10S is inverted at the time T0, the data D0 of the delay time Td is written to the OP register by the first interrupt processing. At time T1, the value of the free-run timer coincides with the value of the OP register, the second interrupt processing is started, and the short-circuit signal 3S is output "H", and at the same time, the data D1 having the pulse width Tp is written to the OP register. It is.
[0029]
At time T2, the value of the free-run timer matches the value of the OP register again, the third interrupt process is started, and the short-circuit signal 3S is set to "L" output. Thereafter, the short-circuit signal 3S maintains the "L" output until the inversion of the zero cross signal 10S occurs again. Here, as for the short-circuit signal 3S, "H" means short-circuit, and "L" means open. The above operation is repeated every time the zero cross signal 10S is input (inverted), and the predetermined short-circuit operation is continued every half cycle of the power supply frequency.
[0030]
A protection method in which the power supply device 13 of this embodiment detects an abnormality of the AC power supply 1 and stops the short-circuit operation will be described. FIG. 4 shows a power supply voltage waveform of the AC power supply 1 and a zero-cross signal 10S generated from the power supply voltage, and an interrupt mask signal for inhibiting the operation of an interrupt process that operates in response to the input of the zero-cross signal 10S. This shows a case where a voltage distortion occurs due to an instantaneous stop or superimposed noise and chattering occurs in the zero cross signal 10S. As shown in FIG. 4, when the zero cross signal 10S causes chattering, the interrupt processing is continuously started and short-circuit operation cannot be performed at a predetermined timing, which may cause an overcurrent or the like.
[0031]
Therefore, as shown in FIG. 4, the interrupt processing associated with the zero cross signal is not executed for a certain time after the input (inversion) of the zero cross signal 10S. In other words, the zero cross signal 10S is not interrupted during the interrupt mask time Tm. Generates an interrupt mask signal that does not accept By the interrupt mask signal processing, even if the power supply environment is bad, the malfunction of the short-circuit operation due to the erroneous detection of the zero cross signal can be eliminated, the occurrence of overcurrent and the stop of the system can be prevented, and the normal operation can be maintained. The interrupt mask signal processing is also effective when the output characteristic of the zero cross detection circuit 10 is poor and the zero cross signal 10S has a circuit configuration that causes chattering.
[0032]
A method of monitoring whether the zero cross signal 10S is correctly input to the control circuit 9 at a predetermined cycle will be described with reference to FIG. In Japan, the power supply frequencies of the commercial AC power supply are 50 Hz and 60 Hz, but this frequency never fluctuates extremely. In the present embodiment, malfunction is mainly prevented when the zero cross signal 10S is generated at a period other than a predetermined period due to a momentary power failure, a lightning surge, or the like.
[0033]
Since the power supply frequency of the commercial AC power supply is stable, once the power supply frequency can be detected, the zero cross signal 10S should be input at a fixed cycle thereafter. Therefore, the period (time) from the point A in FIG. 5 where the zero cross signal 10S is input to the point C where the zero cross signal 10S is next input is measured, and the period is set to the period of the power supply frequency or a period near the same. It is confirmed that the short-circuit signal 3S is stopped. If not, the short-circuit signal 3S is stopped ("L" output). Alternatively, only the time at point C where the zero cross signal 10S is input and the time at point C at which the next zero cross signal 10S is to be input or at a time near the time (points B to D) are obtained. Input may be accepted. By these methods, an erroneous zero cross signal 10S, noise, or the like falling outside the predetermined cycle or time can be eliminated.
[0034]
The abnormality determination method for the zero cross signal 10S will be described with reference to the flowchart shown in FIG. In the step of FIG. 6A, the time interval from the input time point A of the zero cross signal 10S shown in FIG. 5A to the next input time point C shown in FIG. 5C is measured. When the time interval (period) matches 8.333 ms (1/60 Hz / 2 (s)) or 10 ms (1/50 Hz / 2 (s)), or the power supply frequency is actually 50 Hz or 60 Hz Since there is a fluctuation of about ± 0.2 Hz, it is determined whether the fluctuation is in the range of 8.30 ms to 8.36 ms or the range of 9.96 ms to 10.04 ms including the fluctuation. If Yes, it is determined that the operation is normal, and the process proceeds to steps (U) and (E). If No, it is determined that the operation is abnormal and the process proceeds to Step (O) to stop the short-circuit operation. Here, if it is determined whether the power supply is 50 Hz or 60 Hz using the cycle measured in step (c), the power supply frequency can be automatically detected.
[0035]
In addition, if the installation location is fixed, the power frequency of the commercial AC power supply is fixed, so that the power frequency does not change during operation, and the change in the power cycle itself is a power abnormality. Therefore, even when the measurement frequency changes during operation, the short-circuit operation is stopped. As a result, it is possible to prevent an abnormal operation due to an erroneous signal input at the same timing as the accidental comparison value (cycle). FIG. 7 shows a flowchart in this case.
[0036]
A method of monitoring whether the zero cross signal 10S is correctly input at a predetermined cycle will be described with reference to FIG. The input of the zero cross signal 10S is not accepted during the period from the time point A to the time point B of the input of the zero cross signal 10S and during the period after the time point D. In other words, the input of the zero cross signal 10S is permitted only in the range from the time point B to the time point D, and is not permitted in any other range. Alternatively, if there is no input of the zero cross signal 10S in the time range in which the input of the zero cross signal 10S is permitted, the short-circuit operation is stopped. In FIG. 8, a case where the power supply frequency is 50 Hz is taken as an example, and a time width T55 from the time point A to the time point B is set to a half cycle of the power supply frequency 55 Hz so as to be able to cope with some frequency fluctuation. The time width T45 up to the time point D is set to be equivalent to a half cycle of the power supply frequency of 45 Hz. When the power supply frequency is f (Hz), the time width from the point A in FIG. 8 may be determined in the range of f ± 0.1f as described above.
[0037]
FIG. 9 shows a zero-cross signal 10S, a short-circuit signal 3S, a short-circuit operation permission signal for permitting / stopping the short-circuit operation from the input state of the zero-cross signal 10S, and an abnormality in the host system when the power supply abnormal state continues continuously. Is shown in a timing chart. FIG. 9 shows a state in which a power failure occurs at time T2 during operation at the power supply frequency of 50 Hz, and there is no input of the zero cross signal 10S after time T2.
[0038]
In this case, the short-circuit signal 3S is output because the zero-cross signal 10S has been correctly input until time T2, but the short-circuit operation is stopped at time T3 because the zero-cross signal 10S is not input. If the zero cross signal 10S is not input even after time T5, the short-circuit operation is stopped and the power supply abnormality signal is notified to the host system. In this embodiment, the operation of the motor that drives the compressor is stopped. Here, the time T5 is a time when a preset time Tw has elapsed from the input time T2 of the last zero cross signal 10S. This embodiment shows a case where the power supply cycle is set to three times. Thus, when the input of the zero cross signal 10S has not been performed for a predetermined time or more, the short-circuit operation is stopped, and at the same time, the system can be stopped by notifying the host system of the abnormality. In addition, since the same operation is performed when the zero-cross detection circuit 10 has failed, it can be used for abnormality determination of the zero-cross detection circuit.
[0039]
With reference to FIG. 10, a method for preventing a malfunction of the overcurrent protection operation due to an erroneous detection of the overcurrent detection circuit will be described. FIG. 10 shows a zero-cross signal 10S, a short-circuit signal 3S, an overcurrent detection signal detected in the input current detection circuit 11 of FIG. 1, an overcurrent flag used inside the microcomputer, and an overcurrent counter (overcurrent counter). 6 is a timing chart showing the relationship between the protection operation count and the overcurrent error signal notified to the host system. FIG. 10 shows a state in which external noise is superimposed on the overcurrent signal. The signal indicated by “F” is an erroneous detection signal, and the signal indicated by “T” is a normal overcurrent signal.
[0040]
If an overcurrent protection operation is performed in response to an erroneous overcurrent signal as shown in FIG. 10, stable control cannot be performed as a system. Therefore, the setting is made so that the short-circuit signal 3S is "H", that is, the short-circuit 3 responds only to the overcurrent signal input during the short-circuit. With this setting, the overcurrent protection does not operate when the overcurrent signal “F” shown in FIG. 10 is input, and the protection operation is performed only when the overcurrent is in a real overcurrent state, so that stable control can be performed. Here, when the overcurrent protection operation is performed, the overcurrent flag inside the microcomputer changes to the “H” state as shown in FIG.
[0041]
In FIG. 10, when the overcurrent protection operation is performed, the overcurrent flag is set to “H”. Thereafter, if the overcurrent flag is "H" at the next edge input of the zero cross signal 10S, the overcurrent counter is down-counted by one and the overcurrent flag is cleared at the same time. When the overcurrent flag is "L", the overcurrent counter is returned to the initial value. By repeating this operation, the number of times (or time) that the protection operation is continuously executed is measured. When the overcurrent counter becomes 0, an overcurrent error signal is output to the host system to notify the abnormality. In this embodiment, the operation of the motor that drives the compressor is stopped.
[0042]
As described above, frequent system stoppage at the time of occurrence of the protection operation can be prevented, and stable system operation can be performed. In addition, the system can be reliably stopped in the event of an abnormal situation where the system must be stopped. Needless to say, the present protection operation can be applied to the power supply abnormality protection operation.
[0043]
Further, in the present embodiment, all the protection operations described above are always performed, so that safety and stability are ensured. The power supply device of the present embodiment is suitable for driving a motor of an air conditioner or a compressor of a refrigerator.
[0044]
【The invention's effect】
As described above, the use of the power supply device of the present invention facilitates protection when an AC power supply is abnormal. In addition, malfunction of the protection operation can be prevented even in a large environment such as external noise, which contributes to system stability. In addition, frequent system stoppage when a protection operation occurs can be prevented, and stable system operation can be performed.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a circuit configuration of a motor control device according to an embodiment.
FIG. 2 is an explanatory diagram of a power factor improvement of the power supply device according to the embodiment and a method of generating a short-circuit signal.
FIG. 3 is an explanatory diagram of a method for generating a short-circuit signal of the power supply device according to the embodiment.
FIG. 4 is an explanatory diagram of an interrupt mask signal of the power supply device according to the embodiment.
FIG. 5 is an explanatory diagram of power cycle abnormality protection of the power supply device according to the embodiment.
FIG. 6 is a flowchart of a zero cross signal abnormality determination of the power supply device according to the embodiment.
FIG. 7 is a flowchart of another method for determining a zero-cross signal abnormality in the power supply device according to the embodiment.
FIG. 8 is an explanatory diagram of power supply cycle protection of the power supply device according to the embodiment.
FIG. 9 is an explanatory diagram of protection during a power failure of the power supply device according to the embodiment.
FIG. 10 is an explanatory diagram of overcurrent protection of the power supply device according to the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... AC power supply, 2 ... Reactor, 3 ... Short circuit, 4 ... Rectifier circuit, 5 ... Switch, 6 ... Smoothing circuit, 7 ... Inverter circuit, 8 ... Motor, 9 ... Control circuit, 10 ... Zero cross detection circuit, 11: input current detection circuit, 12: DC current detection circuit, 3S: short circuit signal, 5S: switching signal, 6S: DC voltage value, 7S: inverter PWM signal, 10S: zero cross signal, 11S: input current value, 12S: DC current value.

Claims

A rectifier circuit for converting the AC power into DC, a zero-cross detection circuit for detecting a zero-cross point of the AC power and outputting a zero-cross signal, and short-circuiting the AC power via a reactor based on the zero-cross signal; In a power supply device including a short circuit and a smoothing circuit connected to an output terminal of the rectifier circuit,
A power supply device comprising: a control unit configured to detect an abnormality of the zero cross signal and stop a short circuit operation of the short circuit.

2. The power supply device according to claim 1, wherein the control unit measures an input cycle of the zero cross signal, and determines that the zero cross signal is abnormal when the input cycle deviates from a predetermined value. A power supply device, wherein the short-circuit operation of the short-circuit is stopped.

2. The power supply device according to claim 1, wherein the control unit determines that the zero cross signal is abnormal when an input cycle of the zero cross signal deviates from a value within a predetermined range, and determines that the short circuit has occurred. 3. A power supply device for stopping a short-circuit operation of the power supply.

4. The power supply device according to claim 3, wherein the predetermined range is 10.04 ms to 9.96 ms when the AC power supply frequency is 50 Hz, and 8.3 ms to 8.36 ms when the AC power supply frequency is 60 Hz. 5. A power supply device, comprising:

2. The power supply device according to claim 1, wherein the abnormality of the zero cross signal is determined based on a change in the input cycle of the zero cross signal, and the short circuit operation of the short circuit is stopped. 3.

2. The power supply device according to claim 1, wherein the abnormality of the zero cross signal is determined by not inputting the zero cross signal for a predetermined time or more, and the short circuit operation of the short circuit is stopped. 3.

2. The power supply device according to claim 1, wherein the input of the zero cross signal is received after a predetermined time has elapsed from the time of input of the zero cross signal.

2. The power supply device according to claim 1, wherein the zero cross signal is determined to be abnormal when the zero cross signal is not input in a range from a first predetermined time to a second predetermined time from the input time of the zero cross signal. And a short-circuit operation of the short-circuit is stopped.

A rectifier circuit for converting the AC power into DC, a zero-cross detection circuit for detecting a zero-cross point of the AC power and outputting a zero-cross signal, and short-circuiting the AC power via a reactor based on the zero-cross signal; In a power supply device including a short circuit, an input current detection circuit, a smoothing circuit connected to an output terminal of the rectifier circuit, and a control circuit,
An overcurrent detection circuit configured to detect an overcurrent from a detection signal of the input current detection circuit; anda control unit configured to stop a short circuit operation of the short circuit based on an overcurrent detection signal output by the overcurrent detection circuit. An overcurrent stop circuit that notifies an upper system of an overcurrent state, and performs the overcurrent stop circuit operation when the short circuit is controlled to be short-circuited.

A rectifier circuit for converting the AC power into DC, a zero-cross detection circuit for detecting a zero-cross point of the AC power and outputting a zero-cross signal, and short-circuiting the AC power via a reactor based on the zero-cross signal; In a power supply device including a short circuit, an input current detection circuit, a smoothing circuit connected to an output terminal of the rectifier circuit, and a control circuit,
An overcurrent detection circuit configured to detect an overcurrent from a detection signal of the input current detection circuit; anda control unit configured to stop a short circuit operation of the short circuit based on an overcurrent detection signal output by the overcurrent detection circuit. A power supply device comprising: an overcurrent stop circuit that notifies an upper system of an overcurrent state, and receives only the overcurrent detection signal generated when the short circuit controls the short circuit.

2. The power supply device according to claim 1, wherein the power supply device includes an inverter circuit connected to the smoothing circuit, and the inverter circuit is driven by a control signal output from the control unit.

The power supply device according to claim 11, wherein the power supply device connects a motor to a load of an inverter circuit, and the control unit detects an overcurrent from an input current detection signal, and the overcurrent detection circuit An overcurrent stop circuit that stops a short circuit operation of the short circuit based on an overcurrent detection signal output by a detection circuit, and notifies an overcurrent state to a host system, wherein the zero cross signal abnormality or the overcurrent A power supply device, wherein the operation of the motor is stopped when the operation of the prevention circuit occurs continuously for a predetermined period and occurs a predetermined number of times.