JP3868265B2

JP3868265B2 - Air conditioner

Info

Publication number: JP3868265B2
Application number: JP2001333954A
Authority: JP
Inventors: 輝夫藤社; 泰山下
Original assignee: Daikin Industries Ltd; Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Daikin Industries Ltd; Panasonic Corp; Panasonic Holdings Corp
Priority date: 2001-10-31
Filing date: 2001-10-31
Publication date: 2007-01-17
Anticipated expiration: 2021-10-31
Also published as: JP2003139418A

Description

【０００１】
【発明の属する技術分野】
この発明は、圧縮機を保護する空気調和機に関する。
【０００２】
【従来の技術】
従来、圧縮機から吐出された冷媒が冷媒回路を循環するヒートポンプ方式の空気調和機において、運転中に冷媒回路の配管内部が析出物やアイスチョーク(氷結)などにより閉塞されて冷媒が流れにくい状態が続くと、圧縮機の内部温度が上昇し、圧縮機内のモータ巻線が高熱により破損したり絶縁性が劣化したりして、運転不能,信頼性低下の原因になるという問題がある。そこで、従来の空気調和機では、圧縮機内部に巻線温度を検出するための温度センサを設けて、その温度センサにより検出された巻線温度が所定温度以上になると、圧縮機の運転を停止して、圧縮機を保護するようにしている。
【０００３】
【発明が解決しようとする課題】
ところが、上記空気調和機では、温度センサにより検出された巻線温度が所定温度のときに圧縮機を停止するだけでは、温度センサを設けるコストが多大になるだけでなく、上記所定温度の設定値によっては実使用運転領域で圧縮機を確実に保護することができず、正常運転時に誤って圧縮機を停止させてしまうという欠点がある。
【０００４】
そこで、この発明の目的は、圧縮機内部に温度センサを設けることなく、低コストで圧縮機を確実に保護できる空気調和機を提供することにある。
【０００５】
【課題を解決するための手段】
上記目的を達成するため、請求項１の空気調和機は、圧縮機,室内熱交換器,減圧手段および室外熱交換器が環状に接続された冷媒回路と、上記圧縮機の運転周波数を制御する制御装置とを備えた空気調和機において、上記室内熱交換器の温度を検出する室内熱交換器温度センサと、室内空気の温度を検出する室内温度センサとを備え、上記制御装置は、暖房運転時、上記室内熱交換器温度センサにより検出された上記室内熱交換器の温度と上記室内温度センサにより検出された上記室内空気の温度との温度差の絶対値が所定温度未満であって、かつ、上記圧縮機の運転周波数が下限周波数以上で、かつ、上記圧縮機に入力される入力電流が、上記圧縮機の保護が必要な所定電流以上の運転領域にあるとき、運転停止条件を満足したものとして上記圧縮機を保護するための運転停止処理を行うことにより、上記圧縮機の巻線温度が上昇しない上記所定電流未満の小入力電流領域で運転停止しないようにすることを特徴としている。
【０００６】
上記請求項１の空気調和機によれば、上記圧縮機,室内熱交換器,減圧手段および室外熱交換器が環状に接続された冷媒回路により暖房運転を行うとき、析出物やアイスチョークなどにより冷媒回路が閉塞されて冷媒流が流れにくい状態が続くと、圧縮機の巻線温度が上昇すると共に、凝縮器として働く室内熱交換器の温度も上昇するが、閉塞率が高くなると、冷媒流量が少なくなるため、室内熱交換器の温度は室内空気の温度に近づく。また、上記圧縮機の運転周波数が例えば３０Ｈz未満の低い周波数の運転領域では、冷媒回路が閉塞しても圧縮機の巻線温度が破損,絶縁劣化を引き起こすような高温にならないので、冷媒回路閉塞時に圧縮機を保護する範囲の下限周波数は上記３０Ｈz以上となる。そこで、上記制御装置により、上記室内熱交換器温度センサにより検出された室内熱交換器の温度と上記室内温度センサにより検出された室内空気の温度との温度差の絶対値が所定温度未満であって、かつ、上記圧縮機の運転周波数が下限周波数(例えば３０Ｈz)以上で、かつ、圧縮機に入力される入力電流が、圧縮機の保護が必要な所定電流以上の運転領域にあるとき、運転停止条件を満足したものとして圧縮機の運転を停止することによって、圧縮機内部に温度センサを設けることなく、低コストで冷媒回路閉塞時の温度上昇による破損,絶縁劣化等から圧縮機を保護できる。また、上記入力電流が小さい場合は、上記圧縮機の巻線温度が上昇しないので、圧縮機に入力される入力電流が保護の必要がある所定電流以上のときのみ、運転停止処理を行うようにすることによって、圧縮機を確実に保護でき、圧縮機の巻線温度が上昇しない小入力電流領域で停止することがないようにできる。
【０００７】
また、請求項２の空気調和機は、圧縮機,室外熱交換器,減圧手段および室内熱交換器が環状に接続された冷媒回路と、上記圧縮機の運転周波数を制御する制御装置とを備えた空気調和機において、上記室外熱交換器の温度を検出する室外熱交換器温度センサと、室外空気の温度を検出する室外温度センサとを備え、上記制御装置は、冷房運転時または除湿運転時、上記室外熱交換器温度センサにより検出された上記室外熱交換器の温度と上記室外温度センサにより検出された上記室外空気の温度との温度差の絶対値が所定温度未満であって、かつ、上記圧縮機の運転周波数が下限周波数以上で、かつ、上記圧縮機に入力される入力電流が、上記圧縮機の保護が必要な所定電流以上の領域にあるとき、運転停止条件を満足したものとして上記圧縮機を保護するための運転停止処理を行うことにより、上記圧縮機の巻線温度が上昇しない上記所定電流未満の小入力電流領域で運転停止しないようにすることを特徴としている。
【０００８】
上記請求項２の空気調和機によれば、上記圧縮機,室外熱交換器,減圧手段および室内熱交換器が環状に接続された冷媒回路により冷房運転または除湿運転を行うとき、析出物やアイスチョークなどにより冷媒回路が閉塞されて冷媒流が流れにくい状態が続くと、圧縮機の巻線温度が上昇すると共に、凝縮器として働く室外熱交換器の温度も上昇するが、閉塞率が高くなると、冷媒流量が少なくなるため、室外熱交換器の温度は室外空気の温度に近づく。また、上記圧縮機の運転周波数が例えば２０Ｈz未満の低い周波数の運転領域では、冷媒回路が閉塞しても圧縮機の巻線温度が破損,絶縁劣化を引き起こすような高温にならないので、冷媒回路閉塞時に圧縮機を保護する範囲の下限周波数は上記２０Ｈz以上となる。そこで、上記制御装置により、上記室外熱交換器温度センサにより検出された室外熱交換器の温度と上記室外温度センサにより検出された室外空気の温度との温度差の絶対値が所定温度未満であって、かつ、上記圧縮機の運転周波数が下限周波数(例えば２０Ｈz)以上で、かつ、圧縮機に入力される入力電流が、圧縮機の保護が必要な所定電流以上の領域にあるとき、運転停止条件を満足したものとして圧縮機の運転を停止することによって、圧縮機内部に温度センサを設けることなく、低コストで冷媒回路閉塞時の温度上昇による破損,絶縁劣化等から圧縮機を保護できる。また、上記入力電流が小さい場合は、上記圧縮機の巻線温度が上昇しないので、圧縮機に入力される入力電流が保護の必要がある所定電流以上のときのみ、運転停止処理を行うようにすることによって、圧縮機を確実に保護でき、圧縮機の巻線温度が上昇しない小入力電流領域で停止することがないようにできる。
【０００９】
【００１０】
【００１１】
また、請求項３の空気調和機は、請求項１または２の空気調和機において、上記制御装置は、上記運転停止条件を満足したときの上記圧縮機の運転周波数が上記下限周波数よりも高い所定周波数未満であるとき、上記運転停止処理を行う前に上記圧縮機の運転周波数を強制的に上記所定周波数に上げても、上記温度差が上記所定温度未満であるときは、上記圧縮機を保護するための運転停止処理を行う一方、上記温度差が上記所定温度以上であるときは、上記圧縮機を保護するための運転停止処理を行わないことを特徴としている。
【００１２】
上記請求項３の空気調和機によれば、上記圧縮機の運転周波数が上記下限周波数以上でかつ所定周波数未満であるときは、圧縮機の運転周波数を強制的に所定周波数に上げて、もう一度、上記制御装置により上記温度差が上記所定温度未満であるか否かを判定することによって、圧縮機の運転停止の判断をより正確に行うことができる。
【００１３】
【発明の実施の形態】
以下、この発明の空気調和機を図示の実施の形態により詳細に説明する。
【００１４】
（第１実施形態）
図１はこの発明の第１実施形態の空気調和機の構成図を示している。この空気調和機は、図１に示すように、圧縮機１と、上記圧縮機１の吐出側に一端が接続された四方弁２と、上記四方弁２の他端に一端が接続された室外熱交換器３と、上記室外熱交換器３の他端に一端が接続されたフィルタ４と、上記フィルタ４の他端に一端が接続された電動膨張弁５と、上記電動膨張弁５の他端に一端が接続されたドライヤ６と、上記ドライヤ６の他端に一端が接続された閉鎖弁７と、上記閉鎖弁７の他端に一端が接続された室内熱交換器８と、上記室内熱交換器８の他端に一端が接続された閉鎖弁９と、上記閉鎖弁９の他端に四方弁２を介して一端が接続され、他端が上記圧縮機１の吸込側に接続されたフィルタ１０とを備えている。上記圧縮機１,四方弁２,室外熱交換器３,フィルタ４,電動膨張弁５,ドライヤ６,閉鎖弁７,室内熱交換器８,閉鎖弁９およびフィルタ１０で冷媒回路を構成している。
【００１５】
また、上記空気調和機は、上記室外熱交換器３の温度を検出する室外熱交換器温度センサ１１と、室外空気の温度を検出する室外温度センサ１２と、室内熱交換器８の温度を検出する室内熱交換器温度センサ１３と、室内空気の温度を検出する室内温度センサ１４とを備えると共に、室外熱交換器３近傍に配置された室外ファン(プロペラファン)１５と、室内熱交換器８近傍に配置された室内ファン(クロスフローファン)１６とを備えている。
【００１６】
また、図２は上記空気調和機の要部の構成を示している。図２に示すように、交流電源５１が室内制御部５０に接続され、その室内制御部５０を介して交流電源５１が室外制御部６０に接続されている。また、上記室内制御部５０は、室内熱交換器温度センサ１３からの室内熱交換器８の温度を表す信号および室内温度センサ１４からの室内空気の温度を表す信号が入力されると共に、室外制御部６０は、室外温度センサ１２により検出された室外空気の温度を表す信号および室外熱交換器温度センサ１１により検出された室外熱交換器３の温度を表す信号が入力される。上記室内制御部５０と室外制御部６０とは互いに制御信号をやり取りし、室内制御部５０と室外制御部６０で制御装置を構成している。
【００１７】
上記室内制御部５０は、リモートコントローラ(図２ではリモコン)５４の指令信号に従って、室内ファンモータ５６を駆動する速度制御回路５５を制御すると共に、異常運転情報を異常運転表示部５７に表示する。また、上記室外制御部６０は、室内制御部５０からの制御信号に従って、室外ファンモータ６７を駆動する速度制御回路６６を制御すると共に、四方弁２と電動膨張弁５を制御し、圧縮機１を駆動するインバータ回路６４を制御する。上記室外制御部６０は、電流センサ６３により検出された圧縮機１の入力電流を表す信号が入力される。
【００１８】
また、図３は冷凍サイクルの閉塞状態を表す閉塞率と運転周波数について、保護すべき領域を説明するための図であり、閉塞率は、
閉塞率＝閉塞断面積／冷媒配管断面積×１００ [％]
で表される。図３において、“全開”が閉塞率０％を表し、“全閉”が閉塞率１００％を表している。
【００１９】
図３に示すように、閉塞率８０％ラインの左側すなわち閉塞率が８０％未満のエリアＡでは、運転周波数の全領域で正常に運転される。一方、閉塞率８０％ラインの右側すなわち閉塞率が８０％以上かつ運転周波数が２０Ｈz未満のエリアＢでは、運転周波数が低速であるので、圧縮機１の温度は、破損,絶縁劣化するほどの高温には上昇しない。そして、閉塞率が８０％以上かつ運転周波数が２０Ｈz以上のエリアＣでは、圧縮機１の温度上昇による破損,絶縁不良などを防ぐために保護制御が必要となる。
【００２０】
なお、上記エリアＣの境界条件である閉塞率が８０％は、所定の暖房負荷運転条件および所定の冷房負荷運転条件において閉塞率に対する圧縮機の巻線温度は、図９に示すように、閉塞率が８０％近傍になると巻線温度限界(圧縮機の仕様により異なる)に達することによる。また、上記エリアＣの境界条件である運転周波数２０Ｈzは、所定の暖房運転条件において閉塞率に対する圧縮機の巻線温度は、図１０に示すように、運転周波数が２０Ｈz近傍になると巻線温度限界(圧縮機の仕様により異なる)に達することによる。
【００２１】
上記構成の空気調和機において、暖房運転時は、四方弁２を点線の切換位置に切り換えて、圧縮機１を駆動すると、圧縮機１から吐出された高温冷媒は、凝縮器としての室内熱交換器８で凝縮した後、電動膨張弁５により減圧され、減圧された冷媒は、蒸発器としての室外熱交換器３で蒸発した後、圧縮機１の吸込側に戻る。一方、冷房運転時は、四方弁２を実線の切換位置に切り換えて、圧縮機１を駆動すると、圧縮機１から吐出された高温冷媒は、凝縮器としての室外熱交換器３で凝縮した後、電動膨張弁５により減圧され、減圧された冷媒は、蒸発器としての室内熱交換器８で蒸発した後、圧縮機１の吸込側に戻る。
【００２２】
図４は暖房運転時の閉塞率に対する圧縮機温度,吐出温度,入力電流,室内熱交換器の温度,室外熱交換器の温度および圧力の変化を示している。図４において、Ｐdは吐出圧力を表し、Ｐsは吸込側圧力を表している。
【００２３】
図４に示すように、閉塞率が高くなるほど圧縮機１の温度は上昇する。また、吐出温度は閉塞率が高くなるほど上昇するが、閉塞率が８０％近くになると、冷媒量が少なくなるために吐出温度は下がり始める。同様に、入力電流も閉塞率が高くなるほど上昇するが、閉塞率８０％よりもさらに手前で、冷媒量が少なくなり負荷が小さくなるために入力電流は下がり始める。また、凝縮器としての室内熱交換器の温度は、閉塞率が高くなるほど上昇するが、閉塞率８０％よりもさらに手前で、ピーク温度となった後、徐々に室内空気の温度に近づいていく。一方、室外熱交換器の温度は、閉塞率が高くなるほど下がり、閉塞率が８０％以上になると上昇して、室内空気の温度に近づいていく。なお、吐出圧力Ｐdは、室内熱交換器の温度と同様の変化を示し、吐出圧力Ｐdと室内熱交換器の温度とは等価とみなせる。一方、吸込側圧力Ｐsは、閉塞率が高くなるほど、徐々に下がる。
【００２４】
図４から明らかなように、凝縮器としての室内熱交換器の温度と室内空気の温度との温度差の絶対値を判定することによって、冷媒回路の閉塞状態による異常運転を判断することが可能となる。なお、冷房運転または除湿運転においても、同様に、凝縮器としての室外熱交換器の温度と室外空気の温度との温度差の絶対値を判定することによって、冷媒回路の閉塞状態による異常運転を判断することが可能となる。
【００２５】
次に、上記空気調和機の室内制御部５０と室外制御部６０による圧縮機１を高熱から保護する保護制御処理について、図５〜図８に示すフローチャートにしたがって説明する。
【００２６】
まず、保護制御処理がスタートすると、図５に示すステップＳ１で運転モードが暖房運転かまたは冷房運転(または除湿運転)であるかを判定して、ステップＳ１で暖房運転であると判定すると、ステップＳ２に進む。
【００２７】
次に、ステップＳ２で圧縮機１の運転周波数が、下限周波数よりも高い所定周波数としての第１所定値以上か否かを判定して、圧縮機１の運転周波数が第１所定値以上であると判定すると、ステップＳ６に進む一方、圧縮機１の運転周波数が第１所定値未満であると判定すると、ステップＳ３に進む。ここで第１所定値は、図３に示すエリアＣのうちの運転周波数が比較的低い低周波数領域の上限値として設定する。
【００２８】
次に、ステップＳ３で圧縮機１の運転周波数が上記下限周波数としての第２所定値(＜第１所定値)以上か否かを判定して、圧縮機１の運転周波数が第２所定値以上であると判定すると、ステップＳ４に進む一方、圧縮機１の運転周波数が第２所定値未満であると判定すると、ステップＳ１に戻る。ここで、第２所定値は、冷媒回路が閉塞しても圧縮機１の巻線温度が破損,絶縁劣化等を引き起こすような高温にならない図３に示すエリアＢの上側であって、エリアＣの下限値(下限周波数)を設定する。
【００２９】
そして、ステップＳ４で圧縮機１の入力電流が所定電流Ｃ未満で、かつ、△Ｔ１が４ｄｅｇ未満である状態が２０分連続したか否かを判定して、条件を満足したときは、ステップＳ５に進む一方、条件を満足しないときは、ステップＳ１に戻る。ここで、所定電流Ｃは、
Ｃ＝Ａ×運転周波数＋Ｂ (Ａ,Ｂは定数)
また、△Ｔ１は、
【数１】

である。
【００３０】
次に、ステップＳ５で圧縮機１の運転周波数を第１所定値に強制的に上げる。
【００３１】
次に、ステップＳ６に進み、タイマＴ１をスタートして、図６に示すステップＳ７に進む。
【００３２】
そして、ステップＳ７で圧縮機１の入力電流が所定電流Ｃ未満で、かつ、△Ｔ１が４ｄｅｇ未満である状態が１０分連続したか否かを判定し、条件を満足したときは、ステップＳ１０に進み、冷凍サイクルの閉塞状態による異常運転と判断し、圧縮機１の運転を停止して、この処理を終了する。
【００３３】
一方、ステップＳ７で条件を満足しないときは、ステップＳ８に進み、タイマＴ１が１２０分未満か否かを判定し、タイマＴ１が１２０分未満であると判定すると、ステップＳ７に戻る一方、タイマＴ１が１２０分以上であると判定すると、ステップＳ９に進み、圧縮機１の運転周波数が第１所定値の強制運転を解除した後、ステップＳ１に戻り、通常の運転周波数で暖房運転を行いこの処理を続ける。
【００３４】
一方、図１のステップＳ１で運転モードが冷房運転(または除湿運転)であると判定すると、図７に示すステップＳ１１に進み、圧縮機１の運転周波数が、下限周波数よりも高い所定周波数としての第３所定値以上か否かを判定して、圧縮機１の運転周波数が第３所定値以上であると判定すると、ステップＳ１５に進む一方、圧縮機１の運転周波数が第３所定値未満であると判定すると、ステップＳ１２に進む。ここで第３所定値は、図３に示すエリアＣのうちの運転周波数が比較的低い低周波数領域の上限値として設定する。
【００３５】
次に、ステップＳ１２で圧縮機１の運転周波数が上記下限周波数としての第４所定値(＜第３所定値)以上か否かを判定して、圧縮機１の運転周波数が第４所定値以上であると判定すると、ステップＳ１３に進む一方、圧縮機１の運転周波数が第４所定値未満であると判定すると、ステップＳ１１に戻る。ここで、第４所定値は、冷媒回路が閉塞しても圧縮機１の巻線温度が破損,絶縁劣化等を引き起こすような高温にならない図３に示すエリアＢの上側であって、エリアＣの下限値(下限周波数)を設定する。
【００３６】
そして、ステップＳ１３で圧縮機１の入力電流が所定電流Ｃ未満で、かつ、△Ｔ２が４ｄｅｇ未満である状態が２０分連続したか否かを判定して、条件を満足したときは、ステップＳ１４に進む一方、条件を満足しないときは、ステップＳ１１に戻る。ここで、△Ｔ２は、
【数２】

である。
【００３７】
次に、ステップＳ１４で圧縮機１の運転周波数を第３所定値に上げる。
【００３８】
次に、ステップＳ１５に進み、タイマＴ２をスタートして、図８に示すステップＳ１６に進む。
【００３９】
そして、ステップＳ１６で圧縮機１の入力電流が所定電流Ｃ未満で、かつ、△Ｔ２が４ｄｅｇ未満である状態が１０分連続したか否かを判定し、条件を満足したときは、ステップＳ１９に進み、冷凍サイクルの閉塞状態による異常運転と判断し、圧縮機１の運転を停止して、この処理を終了する。
【００４０】
一方、ステップＳ１６で条件を満足しないときは、ステップＳ１７に進み、タイマＴ２が１２０分未満か否かを判定し、タイマＴ２が１２０分未満であると判定すると、ステップＳ１６に戻る一方、タイマＴ２が１２０分以上であると判定すると、ステップＳ１８に進み、圧縮機１の運転周波数が第３所定値の強制運転を解除した後、ステップＳ１１に戻り、通常の運転周波数で冷房運転(または除湿運転)を行い、この処理を続ける。
【００４１】
このように、暖房運転時、室内制御部５０と室外制御部６０により、室内熱交換器温度センサ１３により検出された室内熱交換器８の温度と室内温度センサ１４により検出された室内空気の温度との温度差△Ｔ１の絶対値が所定温度(４ｄｅｇ)未満であって、かつ、圧縮機１の運転周波数が下限周波数(第２所定値)以上のとき、運転停止条件を満足したものとして圧縮機１の運転を停止することによって、圧縮機１内部に温度センサを設けることなく、低コストで暖房運転時の冷媒回路閉塞時の温度上昇による破損,絶縁劣化等から圧縮機を保護することができる。
【００４２】
また、冷房運転(または除湿運転)時、室内制御部５０と室外制御部６０により、室外熱交換器温度センサ１１により検出された室外熱交換器３の温度と室外温度センサ１２により検出された室外空気の温度との温度差△Ｔ２の絶対値が所定温度(４ｄｅｇ)未満であって、かつ、圧縮機１の運転周波数が下限周波数(第４所定値)以上のとき、運転停止条件を満足したものとして圧縮機１の運転を停止することによって、圧縮機１内部に温度センサを設けることなく、低コストで冷房運転(または除湿運転)時の冷媒回路閉塞時の温度上昇による破損,絶縁劣化等から圧縮機を保護することができる。
【００４３】
また、上記圧縮機１に入力される入力電流が保護の必要がある所定電流Ｃ以上のときのみ、運転停止処理を行うようにすることによって、圧縮機１を確実に保護できると共に、圧縮機の巻線温度が上昇しない小入力電流領域で停止することを防止することができる。
【００４４】
また、上記保護制御処理では、運転周波数が第２所定値以上かつ第１所定値未満(または第４所定値以上かつ第３所定値未満)のときは、１段目の判定を行った後、その判定条件を満足した場合に運転周波数を第１所定値(または第３所定値未満)に上げて強制運転して、２段目の判定を行うことによって、誤った判定をすることなく、確実に圧縮機の運転を停止して保護することができる。
【００４５】
（第２実施形態）
上記第１実施形態では、室内熱交換器を１つ備えた空気調和機について説明したが、この第２実施形態では、第１室内熱交換器と第２室内熱交換器を備え、冷房サイクルにおいて第１室内熱交換器を凝縮器とし、第２室内熱交換器を蒸発器として働かせて除湿を行う再熱ドライ運転を行う空気調和機について説明する。
【００４６】
図１１はこの発明の第２実施形態の空気調和機の構成図を示している。なお、制御装置は、上記第１実施形態の図２と同様の構成をしている。
【００４７】
上記空気調和機は、図１１に示すように、圧縮機２１と、上記圧縮機２１の吐出側に一端が接続された四方弁２２と、上記四方弁２２の他端に一端が接続された室外熱交換器２３と、上記室外熱交換器２３の他端に一端が接続されたフィルタ２４と、上記フィルタ２４の他端に一端が接続された電動膨張弁２５と、上記電動膨張弁２５の他端に一端が接続されたドライヤ２６と、上記ドライヤ２６の他端に一端が接続された閉鎖弁２７と、上記閉鎖弁７の他端に一端が接続された第１室内熱交換器２８と、上記第１室内熱交換器２８の他端に一端が接続された分岐部２９と、上記分岐部２９の一方の分岐端に一端が接続された電磁弁３０と、上記分岐部２９の他方の分岐端に一端が接続されたキャピラリ３１と、上記キャピラリ３１の他端に一端が接続され、一端が電動弁３０の他端に接続されたフィルタ３２と、上記電磁弁３０の他端に一端が接続された第２室内熱交換器３３と、上記第２室内熱交換器３３の他端に一端が接続された閉鎖弁３４と、上記閉鎖弁３４の他端に四方弁２２を介して一端が接続され、他端が上記圧縮機１の吸込側に接続されたフィルタ３５とを備えている。上記圧縮機２１,四方弁２２,室外熱交換器２３,フィルタ２４,電動膨張弁２５,ドライヤ２６,閉鎖弁２７,第１室内熱交換器２８,分岐部２９,電磁弁３０,キャピラリ３１,フィルタ３２,第２室内熱交換器３３,閉鎖弁３４およびフィルタ３５で冷媒回路を構成している。
【００４８】
また、上記空気調和機は、上記室外熱交換器２３の温度を検出する室外熱交換器温度センサ４１と、室外空気の温度を検出する室外温度センサ４２と、第２室内熱交換器３３の温度を検出する室内熱交換器温度センサ４３と、室内空気の温度を検出する室内温度センサ４４とを備えると共に、室外熱交換器２３近傍に配置された室外ファン(プロペラファン)４５と、第１,第２室内熱交換器２８,３３近傍に配置された室内ファン(クロスフローファン)４６とを備えている。
【００４９】
上記構成の空気調和機において、暖房運転時は、四方弁２２を点線の切換位置に切り換えて、電磁弁３０を開いた状態で圧縮機２１を駆動すると、圧縮機２１から吐出された高温冷媒は、凝縮器としての第２室内熱交換器３３,第１室内熱交換器２８で凝縮した後、電動膨張弁２５により減圧され、減圧された冷媒は、蒸発器としての室外熱交換器２３で蒸発した後、圧縮機２１の吸込側に戻る。一方、冷房運転時は、四方弁２２を実線の切換位置に切り換えて、電磁弁３０を開いた状態で圧縮機２１を駆動すると、圧縮機２１から吐出された高温冷媒は、凝縮器としての室外熱交換器２３で凝縮した後、電動膨張弁２５により減圧され、減圧された冷媒は、蒸発器としての第１室内熱交換器２８,第２室内熱交換器３３で蒸発した後、圧縮機２１の吸込側に戻る。
【００５０】
一方、再熱ドライ運転時は、四方弁２２を実線の切換位置に切り換えて、電動膨張弁２５を全開にし、電磁弁３０を閉じた状態で圧縮機２１を駆動すると、圧縮機２１から吐出された高温冷媒は、凝縮器としての室外熱交換器２３,第１室内熱交換器２８で凝縮した後、キャピラリ３１により減圧され、減圧された冷媒は、蒸発器としての第２室内熱交換器３３で蒸発した後、圧縮機２１の吸込側に戻る。
【００５１】
この第２実施形態の空気調和機は、第１実施形態の空気調和機と同じ保護制御処理を行い、同様の効果を有する。
【００５２】
上記第１,第２実施形態では、室内熱交換器８の温度と室内空気の温度との温度差の絶対値△Ｔ１および室外熱交換器３の温度と室外空気の温度との温度差の絶対値△Ｔ２の判定に用いる所定温度を４ｄｅｇとしたが、上記所定温度はこれに限らず、空気調和機の能力等に応じて適宜設定すればよい。
【００５３】
【発明の効果】
以上より明らかなように、請求項１の発明の空気調和機は、圧縮機,室内熱交換器,減圧手段および室外熱交換器が環状に接続された冷媒回路と、上記圧縮機の運転周波数を制御する制御装置とを備えた空気調和機において、暖房運転時、上記制御装置によって、室内熱交換器温度センサにより検出された室内熱交換器の温度と室内温度センサにより検出された室内空気の温度との温度差の絶対値が所定温度未満であって、かつ、圧縮機の運転周波数が下限周波数以上で、かつ、圧縮機に入力される入力電流が、圧縮機の保護が必要な所定電流以上の運転領域にあるとき、運転停止条件を満足したものとして圧縮機を保護するための運転停止処理を行うので、圧縮機内部に温度センサを設けることなく、低コストで冷媒回路閉塞時の温度上昇による破損,絶縁劣化等から圧縮機を保護することができる。また、上記制御装置によって、圧縮機に入力される入力電流が保護の必要がある所定電流以上のときのみ、運転停止処理を行うことにより、圧縮機の巻線温度が上昇しない上記所定電流未満の小入力電流領域で運転停止しないようにすることによって、圧縮機を確実に保護できると共に、圧縮機の巻線温度が上昇しない小入力電流領域で停止することがないようにできる。
【００５４】
また、請求項２の発明の空気調和機によれば、圧縮機,室外熱交換器,減圧手段および室内熱交換器が環状に接続された冷媒回路と、上記圧縮機の運転周波数を制御する制御装置とを備えた空気調和機において、冷房運転時または除湿運転時、上記制御装置によって、室外温度センサにより検出された室外空気の温度と室外熱交換器温度センサにより検出された室外熱交換器の温度との温度差の絶対値が所定温度未満であって、かつ、圧縮機の運転周波数が下限周波数以上で、かつ、圧縮機に入力される入力電流が、圧縮機の保護が必要な所定電流以上の領域にあるとき、運転停止条件を満足したものとして圧縮機を保護するための運転停止処理を行うので、圧縮機内部に温度センサを設けることなく、低コストで冷媒回路閉塞時の温度上昇による破損,絶縁劣化等から圧縮機を保護することができる。また、上記制御装置によって、圧縮機に入力される入力電流が保護の必要がある所定電流以上のときのみ、運転停止処理を行うことにより、圧縮機の巻線温度が上昇しない上記所定電流未満の小入力電流領域で運転停止しないようにすることによって、圧縮機を確実に保護できると共に、圧縮機の巻線温度が上昇しない小入力電流領域で停止することがないようにできる。
【００５５】
【００５６】
また、請求項３の発明の空気調和機によれば、請求項１または２の空気調和機において、上記制御装置は、上記運転停止条件を満足したときの圧縮機の運転周波数が下限周波数よりも高い所定周波数未満であるとき、上記運転停止処理を行う前に圧縮機の運転周波数を強制的に所定周波数に上げて、上記温度差が所定温度未満であるとき、圧縮機を保護するための運転停止処理を行う一方、上記温度差が所定温度以上であるとき、圧縮機を保護するための運転停止処理を行わないので、圧縮機の運転を停止する判断をより正確に行うことができる。
【図面の簡単な説明】
【図１】図１はこの発明の第１実施形態の空気調和機の構成図である。
【図２】図２は上記空気調和機の要部の構成を示すブロック図である。
【図３】図３は上記空気調和機の冷凍サイクルの閉塞状態と運転周波数について保護すべき領域について説明するための図である。
【図４】図４は上記空気調和機の暖房運転時の閉塞率に対する圧縮機温度,吐出温度,入力電流,室内熱交換器の温度,室外熱交換器の温度および圧力の変化を示す図である。
【図５】図５は上記空気調和機の保護制御処理を説明するフローチャートである。
【図６】図６は図５に続くフローチャートである。
【図７】図７は図５に続くフローチャートである。
【図８】図８は図７に続くフローチャートである。
【図９】図９は閉塞率と圧縮機の巻線温度との関係を示す図である。
【図１０】図１０は運転周波数と圧縮機の巻線温度との関係を示す図である。
【図１１】図１１はこの発明の第２実施形態の空気調和機の構成図である。
【符号の説明】
１,２１…圧縮機、
２,２２…四方弁、
３,２３…室外熱交換器、
４,１０,２４,３２,３５…フィルタ、
５,２５…電動膨張弁、
６,２６…ドライヤ、
７,９,２７,３４…閉鎖弁、
８…室内熱交換器、
１１,４１…室外熱交換器温度センサ、
１２,４２…室外温度センサ、
１３,４３…室内熱交換器温度センサ、
１４,４４…室内温度センサ
１５,４５…室外ファン、
１６,４６…室内ファン、
２８…第１室内熱交換器、
２９…分岐部、
３０…電磁弁、
３１…キャピラリ、
３３…第２室内熱交換器、
５０…室内制御部、
５１…交流電源、
５４…リモコン、
５５…速度制御回路、
５６…室内ファンモータ、
５７…異常運転表示部、
６０…室外制御部、
６３…電流センサ、
６４…インバータ回路、
６６…速度制御回路、
６７…室外ファンモータ。[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an air conditioner that protects a compressor.
[0002]
[Prior art]
  Conventionally, in a heat pump type air conditioner in which refrigerant discharged from the compressor circulates in the refrigerant circuit, the refrigerant circuit piping is blocked by precipitates or ice chalk (freezing) during operation and the refrigerant does not flow easily If this continues, there is a problem that the internal temperature of the compressor rises and the motor windings in the compressor are damaged by high heat or the insulation is deteriorated, resulting in inoperability and reduced reliability. Therefore, in a conventional air conditioner, a temperature sensor for detecting the winding temperature is provided inside the compressor, and when the winding temperature detected by the temperature sensor exceeds a predetermined temperature, the operation of the compressor is stopped. And protect the compressor.
[0003]
[Problems to be solved by the invention]
  However, in the air conditioner, simply stopping the compressor when the winding temperature detected by the temperature sensor is a predetermined temperature not only increases the cost of providing the temperature sensor, but also sets the predetermined temperature. In some cases, the compressor cannot be reliably protected in the actual operation range, and the compressor is erroneously stopped during normal operation.
[0004]
  Therefore, an object of the present invention is to provide an air conditioner that can reliably protect a compressor at a low cost without providing a temperature sensor inside the compressor.
[0005]
[Means for Solving the Problems]
  In order to achieve the above object, an air conditioner according to claim 1 controls a refrigerant circuit in which a compressor, an indoor heat exchanger, a pressure reducing means, and an outdoor heat exchanger are connected in an annular shape, and an operating frequency of the compressor. An air conditioner comprising a control device, comprising: an indoor heat exchanger temperature sensor for detecting the temperature of the indoor heat exchanger; and an indoor temperature sensor for detecting the temperature of the indoor air, wherein the control device comprises a heating operation The absolute value of the temperature difference between the temperature of the indoor heat exchanger detected by the indoor heat exchanger temperature sensor and the temperature of the indoor air detected by the indoor temperature sensor is less than a predetermined temperature, and When the operating frequency of the compressor is equal to or higher than the lower limit frequency and the input current input to the compressor is in an operating range of a predetermined current or higher that requires protection of the compressor, the operation stop condition is satisfied. As a thing Stopping the operation process for protecting the serial compressorBy doing so, the operation is prevented from being stopped in a small input current region less than the predetermined current at which the winding temperature of the compressor does not increase.It is characterized by that.
[0006]
  According to the air conditioner of the first aspect, when the heating operation is performed by the refrigerant circuit in which the compressor, the indoor heat exchanger, the pressure reducing unit, and the outdoor heat exchanger are connected in an annular shape, If the refrigerant circuit is blocked and the refrigerant flow does not flow easily, the winding temperature of the compressor rises and the temperature of the indoor heat exchanger that functions as a condenser also rises. Therefore, the temperature of the indoor heat exchanger approaches the temperature of room air. Also, in the low frequency operating region where the operating frequency of the compressor is lower than 30 Hz, for example, even if the refrigerant circuit is blocked, the winding temperature of the compressor is not damaged and does not reach a high temperature causing insulation deterioration. Sometimes the lower limit frequency of the range protecting the compressor is above 30 Hz. Therefore, the absolute value of the temperature difference between the temperature of the indoor heat exchanger detected by the indoor heat exchanger temperature sensor and the temperature of the indoor air detected by the indoor temperature sensor is less than a predetermined temperature by the control device. And when the operating frequency of the compressor is equal to or higher than the lower limit frequency (for example, 30 Hz) and the input current input to the compressor is in an operating range higher than a predetermined current that requires protection of the compressor. By stopping the compressor operation assuming that the stop condition is satisfied, it is possible to protect the compressor from damage due to temperature rise, insulation deterioration, etc. at low cost without providing a temperature sensor inside the compressor. . In addition, when the input current is small, the winding temperature of the compressor does not rise, so that the operation stop process is performed only when the input current input to the compressor is equal to or higher than a predetermined current that needs to be protected. By doing so, the compressor can be reliably protected, and the compressor winding temperature can be prevented from stopping in a small input current region where the winding temperature does not rise.
[0007]
  According to a second aspect of the present invention, there is provided an air conditioner comprising: a refrigerant circuit in which a compressor, an outdoor heat exchanger, a decompression means, and an indoor heat exchanger are connected in an annular shape; and a control device that controls an operating frequency of the compressor. The air conditioner includes an outdoor heat exchanger temperature sensor that detects the temperature of the outdoor heat exchanger, and an outdoor temperature sensor that detects the temperature of the outdoor air, and the control device is in a cooling operation or a dehumidifying operation. The absolute value of the temperature difference between the temperature of the outdoor heat exchanger detected by the outdoor heat exchanger temperature sensor and the temperature of the outdoor air detected by the outdoor temperature sensor is less than a predetermined temperature, and When the operation frequency of the compressor is equal to or higher than the lower limit frequency, and the input current input to the compressor is in a region of a predetermined current or higher that requires protection of the compressor, the operation stop condition is satisfied. Above pressure Stopping the operation process for protecting the machineBy Do not stop operation in a small input current range below the specified current that does not increase the winding temperature of the compressor.It is characterized by that.
[0008]
  According to the air conditioner of claim 2, when the cooling operation or the dehumidifying operation is performed by the refrigerant circuit in which the compressor, the outdoor heat exchanger, the pressure reducing means, and the indoor heat exchanger are connected in a ring shape, If the refrigerant circuit is blocked by choke or the like and the refrigerant flow does not flow easily, the winding temperature of the compressor rises and the temperature of the outdoor heat exchanger that acts as a condenser also rises. Since the refrigerant flow rate decreases, the temperature of the outdoor heat exchanger approaches the temperature of the outdoor air. Also, in the low frequency operating region where the operating frequency of the compressor is lower than 20 Hz, for example, even if the refrigerant circuit is blocked, the winding temperature of the compressor is not damaged and does not reach a high temperature causing insulation deterioration. Sometimes the lower limit frequency of the range protecting the compressor is 20 Hz or more. Therefore, the absolute value of the temperature difference between the temperature of the outdoor heat exchanger detected by the outdoor heat exchanger temperature sensor and the temperature of the outdoor air detected by the outdoor temperature sensor is less than a predetermined temperature by the control device. In addition, when the operating frequency of the compressor is equal to or higher than the lower limit frequency (for example, 20 Hz) and the input current input to the compressor is in a region higher than a predetermined current that requires protection of the compressor, the operation is stopped. By stopping the operation of the compressor assuming that the conditions are satisfied, it is possible to protect the compressor from damage due to temperature rise, deterioration of insulation, and the like at a low cost without providing a temperature sensor inside the compressor. In addition, when the input current is small, the winding temperature of the compressor does not rise, so that the operation stop process is performed only when the input current input to the compressor is equal to or higher than a predetermined current that needs to be protected. By doing so, the compressor can be reliably protected, and the compressor winding temperature can be prevented from stopping in a small input current region where the winding temperature does not rise.
[0009]
[0010]
[0011]
  According to a third aspect of the present invention, there is provided the air conditioner according to the first or second aspect, wherein the control device has a predetermined operating frequency of the compressor higher than the lower limit frequency when the operation stop condition is satisfied. When the temperature difference is less than the predetermined temperature even if the operating frequency of the compressor is forcibly increased to the predetermined frequency before performing the operation stop process when the frequency is lower than the frequency, the compressor is protected. On the other hand, when the temperature difference is equal to or higher than the predetermined temperature, the operation stop process for protecting the compressor is not performed.
[0012]
  According to the air conditioner of claim 3, when the operating frequency of the compressor is equal to or higher than the lower limit frequency and lower than a predetermined frequency, the operating frequency of the compressor is forcibly increased to a predetermined frequency, By determining whether or not the temperature difference is less than the predetermined temperature by the control device, it is possible to more accurately determine whether or not to stop the compressor.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, the air conditioner of this invention is demonstrated in detail by embodiment of illustration.
[0014]
  (First embodiment)
  FIG. 1 shows a configuration diagram of an air conditioner according to a first embodiment of the present invention. As shown in FIG. 1, this air conditioner includes a compressor 1, a four-way valve 2 having one end connected to the discharge side of the compressor 1, and an outdoor unit having one end connected to the other end of the four-way valve 2. A heat exchanger 3; a filter 4 having one end connected to the other end of the outdoor heat exchanger 3; an electric expansion valve 5 having one end connected to the other end of the filter 4; A dryer 6 having one end connected to the end, a closing valve 7 having one end connected to the other end of the dryer 6, an indoor heat exchanger 8 having one end connected to the other end of the closing valve 7, and the indoor A closing valve 9 having one end connected to the other end of the heat exchanger 8, one end connected to the other end of the closing valve 9 via the four-way valve 2, and the other end connected to the suction side of the compressor 1. The filter 10 is provided. The compressor 1, the four-way valve 2, the outdoor heat exchanger 3, the filter 4, the electric expansion valve 5, the dryer 6, the closing valve 7, the indoor heat exchanger 8, the closing valve 9 and the filter 10 constitute a refrigerant circuit. .
[0015]
  The air conditioner detects the temperature of the outdoor heat exchanger 3 that detects the temperature of the outdoor heat exchanger 3, the outdoor temperature sensor 12 that detects the temperature of outdoor air, and the temperature of the indoor heat exchanger 8. An indoor heat exchanger temperature sensor 13 and an indoor temperature sensor 14 for detecting the temperature of the indoor air, an outdoor fan (propeller fan) 15 disposed in the vicinity of the outdoor heat exchanger 3, and an indoor heat exchanger 8 And an indoor fan (cross flow fan) 16 disposed in the vicinity.
[0016]
  Moreover, FIG. 2 has shown the structure of the principal part of the said air conditioner. As shown in FIG. 2, an AC power supply 51 is connected to the indoor control unit 50, and the AC power supply 51 is connected to the outdoor control unit 60 via the indoor control unit 50. The indoor control unit 50 receives a signal indicating the temperature of the indoor heat exchanger 8 from the indoor heat exchanger temperature sensor 13 and a signal indicating the temperature of the indoor air from the indoor temperature sensor 14, and also controls the outdoor control. The unit 60 receives a signal indicating the temperature of the outdoor air detected by the outdoor temperature sensor 12 and a signal indicating the temperature of the outdoor heat exchanger 3 detected by the outdoor heat exchanger temperature sensor 11. The indoor control unit 50 and the outdoor control unit 60 exchange control signals with each other, and the indoor control unit 50 and the outdoor control unit 60 constitute a control device.
[0017]
  The indoor control unit 50 controls the speed control circuit 55 that drives the indoor fan motor 56 in accordance with a command signal from a remote controller (remote controller in FIG. 2), and displays abnormal operation information on the abnormal operation display unit 57. The outdoor control unit 60 controls the speed control circuit 66 that drives the outdoor fan motor 67 in accordance with a control signal from the indoor control unit 50, and controls the four-way valve 2 and the electric expansion valve 5. The inverter circuit 64 for driving is controlled. The outdoor control unit 60 receives a signal representing the input current of the compressor 1 detected by the current sensor 63.
[0018]
  Moreover, FIG. 3 is a figure for demonstrating the area | region which should be protected about the obstruction | occlusion rate and operating frequency showing the obstruction | occlusion state of a refrigerating cycle,
      Blockage rate = Blocking cross-sectional area / Refrigerant piping cross-sectional area x 100 [%]
It is represented by In FIG. 3, “fully open” represents a blockage rate of 0%, and “fully closed” represents a blockage rate of 100%.
[0019]
  As shown in FIG. 3, in the left side of the line with the blockage rate of 80%, that is, in the area A where the blockage rate is less than 80%, the operation is normally performed in the entire region of the operation frequency. On the other hand, in the area B on the right side of the 80% blockage rate line, that is, in the area B where the blockage rate is 80% or more and the operation frequency is less than 20 Hz, the operation frequency is low, so the temperature of the compressor 1 is high enough to cause breakage and insulation deterioration. Does not rise. In area C where the blockage rate is 80% or more and the operation frequency is 20 Hz or more, protection control is required to prevent damage, insulation failure, and the like due to the temperature rise of the compressor 1.
[0020]
  Note that when the blockage rate that is the boundary condition of the area C is 80%, the winding temperature of the compressor with respect to the blockage rate in the predetermined heating load operation condition and the predetermined cooling load operation condition is as shown in FIG. When the rate is close to 80%, it reaches the winding temperature limit (depending on the compressor specifications). In addition, the operating frequency 20 Hz which is the boundary condition of the area C is that the coil winding temperature of the compressor with respect to the blockage rate in a predetermined heating operation condition is, as shown in FIG. 10, the winding temperature limit when the operating frequency is near 20 Hz. (Depending on the compressor specifications).
[0021]
  In the air conditioner having the above-described configuration, when the four-way valve 2 is switched to the dotted line switching position and the compressor 1 is driven during the heating operation, the high-temperature refrigerant discharged from the compressor 1 is subjected to indoor heat exchange as a condenser. After being condensed in the compressor 8, the pressure is reduced by the electric expansion valve 5, and the reduced pressure refrigerant is evaporated in the outdoor heat exchanger 3 as an evaporator, and then returns to the suction side of the compressor 1. On the other hand, during the cooling operation, when the four-way valve 2 is switched to the solid line switching position and the compressor 1 is driven, the high-temperature refrigerant discharged from the compressor 1 is condensed in the outdoor heat exchanger 3 as a condenser. The refrigerant decompressed by the electric expansion valve 5 evaporates in the indoor heat exchanger 8 as an evaporator and then returns to the suction side of the compressor 1.
[0022]
  FIG. 4 shows changes in compressor temperature, discharge temperature, input current, indoor heat exchanger temperature, outdoor heat exchanger temperature and pressure with respect to the blockage rate during heating operation. In FIG. 4, Pd represents the discharge pressure, and Ps represents the suction side pressure.
[0023]
  As shown in FIG. 4, the temperature of the compressor 1 increases as the blockage rate increases. The discharge temperature increases as the blockage rate increases, but when the blockage rate approaches 80%, the discharge amount starts to decrease because the amount of refrigerant decreases. Similarly, the input current increases as the blockage rate increases, but the input current begins to decrease because the amount of refrigerant decreases and the load decreases further before the blockage rate of 80%. Further, the temperature of the indoor heat exchanger as the condenser increases as the blockage rate increases, but after reaching the peak temperature even before the blockage rate of 80%, it gradually approaches the temperature of the room air. . On the other hand, the temperature of the outdoor heat exchanger decreases as the blockage rate increases, and increases when the blockage rate reaches 80% or more, and approaches the temperature of the room air. The discharge pressure Pd shows the same change as the temperature of the indoor heat exchanger, and the discharge pressure Pd and the temperature of the indoor heat exchanger can be regarded as equivalent. On the other hand, the suction side pressure Ps gradually decreases as the blocking rate increases.
[0024]
  As is apparent from FIG. 4, it is possible to determine abnormal operation due to the blocked state of the refrigerant circuit by determining the absolute value of the temperature difference between the temperature of the indoor heat exchanger as the condenser and the temperature of the indoor air. It becomes. Similarly, in the cooling operation or the dehumidifying operation, the abnormal operation due to the blocked state of the refrigerant circuit is similarly determined by determining the absolute value of the temperature difference between the temperature of the outdoor heat exchanger as the condenser and the temperature of the outdoor air. It becomes possible to judge.
[0025]
  Next, protection control processing for protecting the compressor 1 from high heat by the indoor control unit 50 and the outdoor control unit 60 of the air conditioner will be described with reference to the flowcharts shown in FIGS.
[0026]
  First, when the protection control process is started, it is determined in step S1 shown in FIG. 5 whether the operation mode is a heating operation or a cooling operation (or a dehumidifying operation). Proceed to S2.
[0027]
  Next, it is determined in step S2 whether or not the operating frequency of the compressor 1 is equal to or higher than a first predetermined value as a predetermined frequency higher than the lower limit frequency, and the operating frequency of the compressor 1 is equal to or higher than the first predetermined value. If it is determined, the process proceeds to step S6, whereas if it is determined that the operating frequency of the compressor 1 is less than the first predetermined value, the process proceeds to step S3. Here, the first predetermined value is set as an upper limit value in a low frequency region where the operation frequency is relatively low in the area C shown in FIG.
[0028]
  Next, in step S3, it is determined whether or not the operating frequency of the compressor 1 is equal to or higher than a second predetermined value (<first predetermined value) as the lower limit frequency, and the operating frequency of the compressor 1 is equal to or higher than a second predetermined value. If it is determined that the operation frequency of the compressor 1 is less than the second predetermined value, the process returns to step S1. Here, the second predetermined value is an upper side of the area B shown in FIG. 3 where the winding temperature of the compressor 1 is not damaged and the insulation temperature is deteriorated even if the refrigerant circuit is blocked, and the area C Set the lower limit value (lower limit frequency).
[0029]
  In step S4, it is determined whether or not the state where the input current of the compressor 1 is less than the predetermined current C and ΔT1 is less than 4 deg is continued for 20 minutes. If the condition is not satisfied, the process returns to step S1. Here, the predetermined current C is
      C = A x operating frequency + B (A and B are constants)
ΔT1 is
[Expression 1]

It is.
[0030]
  Next, in step S5, the operating frequency of the compressor 1 is forcibly increased to a first predetermined value.
[0031]
  Next, it progresses to step S6, the timer T1 is started, and it progresses to step S7 shown in FIG.
[0032]
  Then, in step S7, it is determined whether or not the state in which the input current of the compressor 1 is less than the predetermined current C and ΔT1 is less than 4 deg has continued for 10 minutes. Then, it is determined that the operation is abnormal due to the closed state of the refrigeration cycle, the operation of the compressor 1 is stopped, and this process is terminated.
[0033]
  On the other hand, when the condition is not satisfied in step S7, the process proceeds to step S8, where it is determined whether or not the timer T1 is less than 120 minutes. If it is determined that the timer T1 is less than 120 minutes, the process returns to step S7, while the timer T1 Is determined to be 120 minutes or more, the process proceeds to step S9, the forced operation with the operating frequency of the compressor 1 is canceled at the first predetermined value, and then the process returns to step S1 to perform the heating operation at the normal operating frequency. Continue.
[0034]
  On the other hand, when it is determined in step S1 of FIG. 1 that the operation mode is the cooling operation (or dehumidifying operation), the process proceeds to step S11 shown in FIG. 7, and the operation frequency of the compressor 1 is set as a predetermined frequency higher than the lower limit frequency. If it is determined whether the operating frequency of the compressor 1 is equal to or higher than the third predetermined value by determining whether the operating frequency is equal to or higher than the third predetermined value, the process proceeds to step S15, while the operating frequency of the compressor 1 is less than the third predetermined value. If it is determined that there is, the process proceeds to step S12. Here, the third predetermined value is set as an upper limit value in a low frequency region where the operation frequency is relatively low in the area C shown in FIG.
[0035]
  Next, in step S12, it is determined whether or not the operating frequency of the compressor 1 is equal to or higher than a fourth predetermined value (<third predetermined value) as the lower limit frequency, and the operating frequency of the compressor 1 is equal to or higher than a fourth predetermined value. If it is determined that the operating frequency of the compressor 1 is less than the fourth predetermined value, the process returns to step S11. Here, the fourth predetermined value is an upper side of the area B shown in FIG. 3 where the winding temperature of the compressor 1 is not damaged and the insulation temperature is deteriorated even if the refrigerant circuit is blocked, and the area C Set the lower limit value (lower limit frequency).
[0036]
  In step S13, it is determined whether or not the state in which the input current of the compressor 1 is less than the predetermined current C and ΔT2 is less than 4 deg is continued for 20 minutes. On the other hand, if the condition is not satisfied, the process returns to step S11. Where ΔT2 is
[Expression 2]

It is.
[0037]
  Next, the operating frequency of the compressor 1 is raised to a third predetermined value in step S14.
[0038]
  Next, it progresses to step S15, the timer T2 is started, and it progresses to step S16 shown in FIG.
[0039]
  In step S16, it is determined whether or not the state where the input current of the compressor 1 is less than the predetermined current C and ΔT2 is less than 4 deg continues for 10 minutes. If the condition is satisfied, the process goes to step S19. Then, it is determined that the operation is abnormal due to the closed state of the refrigeration cycle, the operation of the compressor 1 is stopped, and this process is terminated.
[0040]
  On the other hand, if the condition is not satisfied in step S16, the process proceeds to step S17 to determine whether or not the timer T2 is less than 120 minutes. If the timer T2 is determined to be less than 120 minutes, the process returns to step S16 while the timer T2 Is determined to be 120 minutes or more, the process proceeds to step S18, after the forced operation of the compressor 1 having the third predetermined value is canceled, the process returns to step S11, and the cooling operation (or dehumidification operation) is performed at the normal operation frequency. ) And continue this process.
[0041]
  As described above, during the heating operation, the indoor controller 50 and the outdoor controller 60 detect the temperature of the indoor heat exchanger 8 detected by the indoor heat exchanger temperature sensor 13 and the temperature of the indoor air detected by the indoor temperature sensor 14. When the absolute value of the temperature difference ΔT1 is less than the predetermined temperature (4 deg) and the operating frequency of the compressor 1 is equal to or higher than the lower limit frequency (second predetermined value), the compressor is compressed as satisfying the operation stop condition. By stopping the operation of the machine 1, it is possible to protect the compressor from damage due to temperature rise, insulation deterioration, etc. at a low cost without providing a temperature sensor inside the compressor 1 during heating operation. it can.
[0042]
  In the cooling operation (or dehumidifying operation), the indoor controller 50 and the outdoor controller 60 detect the temperature of the outdoor heat exchanger 3 detected by the outdoor heat exchanger temperature sensor 11 and the outdoor temperature detected by the outdoor temperature sensor 12. The operation stop condition was satisfied when the absolute value of the temperature difference ΔT2 from the air temperature was less than the predetermined temperature (4 deg) and the operating frequency of the compressor 1 was equal to or higher than the lower limit frequency (fourth predetermined value). By stopping the operation of the compressor 1 as a matter of course, without providing a temperature sensor inside the compressor 1, damage due to temperature rise at the time of the refrigerant circuit blockage during cooling operation (or dehumidification operation), insulation deterioration, etc. Can protect the compressor from.
[0043]
  Further, by performing the operation stop process only when the input current input to the compressor 1 is equal to or higher than the predetermined current C that needs to be protected, the compressor 1 can be reliably protected, and the compressor Stopping in a small input current region where the winding temperature does not rise can be prevented.
[0044]
  In the protection control process, when the operation frequency is equal to or higher than the second predetermined value and lower than the first predetermined value (or higher than the fourth predetermined value and lower than the third predetermined value), the first stage determination is performed, When the determination condition is satisfied, the operation frequency is increased to the first predetermined value (or less than the third predetermined value), the operation is forcibly performed, and the second determination is performed, so that an erroneous determination can be made without making an erroneous determination. It is possible to protect the compressor by stopping the operation.
[0045]
  (Second Embodiment)
  In the said 1st Embodiment, although the air conditioner provided with one indoor heat exchanger was demonstrated, in this 2nd Embodiment, the 1st indoor heat exchanger and the 2nd indoor heat exchanger are provided, and it is in a cooling cycle. An air conditioner that performs a reheat dry operation in which dehumidification is performed by using the first indoor heat exchanger as a condenser and the second indoor heat exchanger as an evaporator will be described.
[0046]
  FIG. 11 shows a configuration diagram of an air conditioner according to a second embodiment of the present invention. The control device has the same configuration as that of FIG. 2 of the first embodiment.
[0047]
  As shown in FIG. 11, the air conditioner includes a compressor 21, a four-way valve 22 having one end connected to the discharge side of the compressor 21, and an outdoor unit having one end connected to the other end of the four-way valve 22. A heat exchanger 23; a filter 24 having one end connected to the other end of the outdoor heat exchanger 23; an electric expansion valve 25 having one end connected to the other end of the filter 24; A dryer 26 having one end connected to the end, a closing valve 27 having one end connected to the other end of the dryer 26, a first indoor heat exchanger 28 having one end connected to the other end of the closing valve 7, A branch portion 29 having one end connected to the other end of the first indoor heat exchanger 28, an electromagnetic valve 30 having one end connected to one branch end of the branch portion 29, and the other branch of the branch portion 29 A capillary 31 having one end connected to the end, and the other end of the capillary 31 A filter 32 having one end connected to the other end of the motor-operated valve 30, a second indoor heat exchanger 33 having one end connected to the other end of the electromagnetic valve 30, and the second indoor heat exchanger. A closing valve 34 having one end connected to the other end of 33, and a filter 35 having one end connected to the other end of the closing valve 34 via the four-way valve 22 and the other end connected to the suction side of the compressor 1. And. The compressor 21, the four-way valve 22, the outdoor heat exchanger 23, the filter 24, the electric expansion valve 25, the dryer 26, the closing valve 27, the first indoor heat exchanger 28, the branch portion 29, the electromagnetic valve 30, the capillary 31, and the filter 32, the second indoor heat exchanger 33, the shut-off valve 34, and the filter 35 constitute a refrigerant circuit.
[0048]
  The air conditioner includes an outdoor heat exchanger temperature sensor 41 that detects the temperature of the outdoor heat exchanger 23, an outdoor temperature sensor 42 that detects the temperature of outdoor air, and the temperature of the second indoor heat exchanger 33. An indoor heat exchanger temperature sensor 43 for detecting the indoor air temperature and an indoor temperature sensor 44 for detecting the temperature of the indoor air, and an outdoor fan (propeller fan) 45 disposed in the vicinity of the outdoor heat exchanger 23; And an indoor fan (cross flow fan) 46 disposed in the vicinity of the second

indoor heat exchangers

28 and 33.
[0049]
  In the air conditioner having the above configuration, during heating operation, when the compressor 21 is driven with the four-way valve 22 switched to the dotted line switching position and the electromagnetic valve 30 opened, the high-temperature refrigerant discharged from the compressor 21 is After being condensed in the second indoor heat exchanger 33 and the first indoor heat exchanger 28 as condensers, the pressure is reduced by the electric expansion valve 25, and the reduced refrigerant evaporates in the outdoor heat exchanger 23 as an evaporator. After that, it returns to the suction side of the compressor 21. On the other hand, during the cooling operation, when the compressor 21 is driven with the four-way valve 22 switched to the solid line switching position and the electromagnetic valve 30 opened, the high-temperature refrigerant discharged from the compressor 21 is outdoors as a condenser. After being condensed in the heat exchanger 23, the pressure is reduced by the electric expansion valve 25, and the reduced pressure refrigerant is evaporated in the first indoor heat exchanger 28 and the second indoor heat exchanger 33 as evaporators, and then the compressor 21. Return to the suction side.
[0050]
  On the other hand, when the reheat dry operation is performed, the compressor 21 is driven with the four-way valve 22 switched to the solid line switching position, the electric expansion valve 25 is fully opened, and the electromagnetic valve 30 is closed. After the high-temperature refrigerant is condensed in the outdoor heat exchanger 23 and the first indoor heat exchanger 28 as condensers, the refrigerant is decompressed by the capillary 31, and the decompressed refrigerant is the second indoor heat exchanger 33 as an evaporator. After evaporating at, return to the suction side of the compressor 21.
[0051]
  The air conditioner of the second embodiment performs the same protection control process as the air conditioner of the first embodiment, and has the same effect.
[0052]
  In the first and second embodiments, the absolute value ΔT1 of the temperature difference between the temperature of the indoor heat exchanger 8 and the temperature of the indoor air and the absolute value of the temperature difference between the temperature of the outdoor heat exchanger 3 and the temperature of the outdoor air. Although the predetermined temperature used for the determination of the value ΔT2 is 4 deg, the predetermined temperature is not limited to this, and may be set as appropriate according to the capability of the air conditioner.
[0053]
【The invention's effect】
  As is clear from the above, the air conditioner of the first aspect of the present invention includes a refrigerant circuit in which a compressor, an indoor heat exchanger, a pressure reducing means, and an outdoor heat exchanger are connected in an annular shape, and an operating frequency of the compressor. In the air conditioner provided with a control device for controlling, the temperature of the indoor heat exchanger detected by the indoor heat exchanger temperature sensor and the temperature of the indoor air detected by the indoor temperature sensor by the control device during the heating operation The absolute value of the temperature difference is less than the predetermined temperature, the compressor operating frequency is equal to or higher than the lower limit frequency, and the input current input to the compressor is equal to or higher than the predetermined current that requires protection of the compressor Because the operation stop process is performed to protect the compressor assuming that the operation stop condition is satisfied, the temperature rise when the refrigerant circuit is closed at low cost without providing a temperature sensor inside the compressor. In That damage, it is possible to protect the compressor from insulation deterioration or the like. Further, the control device performs the operation stop process only when the input current input to the compressor is equal to or higher than a predetermined current that needs to be protected.Therefore, the compressor winding temperature does not rise, and the operation is not stopped in a small input current region below the predetermined current.By doing so, the compressor can be reliably protected, and it can be prevented from stopping in a small input current region where the winding temperature of the compressor does not rise.
[0054]
  According to the air conditioner of the second aspect of the invention, the refrigerant circuit in which the compressor, the outdoor heat exchanger, the pressure reducing means, and the indoor heat exchanger are connected in a ring shape, and the control for controlling the operating frequency of the compressor In the air conditioner equipped with the apparatus, during the cooling operation or the dehumidifying operation, the temperature of the outdoor air detected by the outdoor temperature sensor and the outdoor heat exchanger temperature sensor is detected by the control device by the control device. The absolute value of the temperature difference from the temperature is less than the predetermined temperature, the operating frequency of the compressor is equal to or higher than the lower limit frequency, and the input current input to the compressor is a predetermined current that requires protection of the compressor When it is in the above range, the shutdown process is performed to protect the compressor as if the shutdown condition has been satisfied, so the temperature rise when the refrigerant circuit is closed at low cost without providing a temperature sensor inside the compressor. In That damage, it is possible to protect the compressor from insulation deterioration or the like. Further, the control device performs the operation stop process only when the input current input to the compressor is equal to or higher than a predetermined current that needs to be protected.Therefore, the compressor winding temperature does not rise, and the operation is not stopped in a small input current region below the predetermined current.By doing so, the compressor can be reliably protected, and it can be prevented from stopping in a small input current region where the winding temperature of the compressor does not rise.
[0055]
[0056]
  Moreover, according to the air conditioner of the invention of claim 3, in the air conditioner of

claim

1 or 2, the control device is configured such that the operating frequency of the compressor when the operation stop condition is satisfied is lower than the lower limit frequency. When the temperature is below a high predetermined frequency, the operation frequency of the compressor is forcibly increased to a predetermined frequency before performing the operation stop processing, and when the temperature difference is less than the predetermined temperature, an operation for protecting the compressor is performed. While the stop process is performed, when the temperature difference is equal to or higher than the predetermined temperature, the operation stop process for protecting the compressor is not performed, so that the determination to stop the operation of the compressor can be made more accurately.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an air conditioner according to a first embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of a main part of the air conditioner.
FIG. 3 is a diagram for explaining a region to be protected with respect to a closed state and an operating frequency of the refrigeration cycle of the air conditioner.
FIG. 4 is a diagram showing changes in compressor temperature, discharge temperature, input current, indoor heat exchanger temperature, outdoor heat exchanger temperature and pressure with respect to the blockage rate during the heating operation of the air conditioner. is there.
FIG. 5 is a flowchart illustrating protection control processing for the air conditioner.
FIG. 6 is a flowchart subsequent to FIG.
FIG. 7 is a flowchart subsequent to FIG.
FIG. 8 is a flowchart subsequent to FIG.
FIG. 9 is a diagram showing the relationship between the blockage rate and the winding temperature of the compressor.
FIG. 10 is a diagram showing the relationship between the operating frequency and the winding temperature of the compressor.
FIG. 11 is a configuration diagram of an air conditioner according to a second embodiment of the present invention.
[Explanation of symbols]
  1,21 ... Compressor,
  2,22 ... Four-way valve,
  3, 23 ... Outdoor heat exchanger,
  4, 10, 24, 32, 35 ... filter,
  5, 25 ... Electric expansion valve,
  6,26 ... dryer,
  7, 9, 27, 34 ... shut-off valve,
  8 ... Indoor heat exchanger,
  11, 41 ... outdoor heat exchanger temperature sensor,
  12, 42 ... outdoor temperature sensor,
  13, 43 ... Indoor heat exchanger temperature sensor,
  14,44 ... Indoor temperature sensor
  15,45 ... outdoor fan,
  16, 46 ... indoor fans,
  28 ... 1st indoor heat exchanger,
  29 ... Branch part,
  30 ... Solenoid valve,
  31 ... capillary,
  33. Second indoor heat exchanger,
  50. Indoor control unit,
  51 ... AC power supply,
  54 ... remote control,
  55. Speed control circuit,
  56 ... Indoor fan motor,
  57: Abnormal operation display section,
  60: outdoor control unit,
  63 ... Current sensor,
  64. Inverter circuit,
  66 ... speed control circuit,
  67: Outdoor fan motor.

Claims

A refrigerant circuit in which the compressor (1), the indoor heat exchanger (8), the pressure reducing means (5) and the outdoor heat exchanger (3) are connected in a ring shape, and a control for controlling the operating frequency of the compressor (1). In an air conditioner equipped with a device (50, 60),
An indoor heat exchanger temperature sensor (13) for detecting the temperature of the indoor heat exchanger (8);
An indoor temperature sensor (14) for detecting the temperature of indoor air,
The controller (50, 60) detects the temperature of the indoor heat exchanger (8) detected by the indoor heat exchanger temperature sensor (13) and the indoor temperature sensor (14) during heating operation. The absolute value of the temperature difference with the temperature of the indoor air is less than a predetermined temperature, the operating frequency of the compressor (1) is not less than the lower limit frequency, and the input is input to the compressor (1) current, when in a predetermined current or more operating space required protection of the compressor (1), by stopping the operation process for protecting the compressor (1) as satisfying the operation stop condition The air conditioner is characterized in that the operation is not stopped in a small input current region less than the predetermined current at which the winding temperature of the compressor ( 1 ) does not increase .

A refrigerant circuit in which the compressor (1), the outdoor heat exchanger (3), the pressure reducing means (5) and the indoor heat exchanger (8) are connected in an annular shape, and a control for controlling the operating frequency of the compressor (1). In an air conditioner equipped with a device (50, 60),
An outdoor heat exchanger temperature sensor (11) for detecting the temperature of the outdoor heat exchanger (3);
An outdoor temperature sensor (12) for detecting the temperature of the outdoor air,
The control device (50, 60) includes the temperature of the outdoor heat exchanger (3) detected by the outdoor heat exchanger temperature sensor (11) during the cooling operation or the dehumidifying operation, and the outdoor temperature sensor (12). The absolute value of the temperature difference with the temperature of the outdoor air detected by the above is less than a predetermined temperature, the operating frequency of the compressor (1) is not less than the lower limit frequency, and the compressor (1) When the input current that is input is in a region that exceeds the predetermined current that needs to be protected by the compressor (1), an operation stop process is performed to protect the compressor (1) as satisfying the operation stop condition. By performing, the air conditioner is characterized in that the operation is not stopped in a small input current region less than the predetermined current at which the winding temperature of the compressor ( 1 ) does not increase .

In the air conditioner according to claim 1 or 2,
When the operation frequency of the compressor (1) when the operation stop condition is satisfied is less than a predetermined frequency higher than the lower limit frequency, the control device (50, 60) performs the operation stop process before performing the operation stop process. Even if the operating frequency of the compressor (1) is forcibly increased to the predetermined frequency, if the temperature difference is less than the predetermined temperature, an operation stop process is performed to protect the compressor (1). On the other hand, when the temperature difference is equal to or higher than the predetermined temperature, the operation stop process for protecting the compressor (1) is not performed.