JP4131129B2

JP4131129B2 - DC motor drive control device

Info

Publication number: JP4131129B2
Application number: JP2002155323A
Authority: JP
Inventors: 陽一宿里; 浩二木下; 真年弥栄
Original assignee: Matsushita Electric Works Ltd
Current assignee: Panasonic Electric Works Co Ltd
Priority date: 2002-05-29
Filing date: 2002-05-29
Publication date: 2008-08-13
Anticipated expiration: 2022-05-29
Also published as: JP2003348877A

Description

【０００１】
【発明の属する技術分野】
本発明は、エアコン，給湯機などの家電機器に使用され、効率の良いＰＷＭ制御で能力可変をするＤＣモータの駆動制御装置に関するものである。
【０００２】
【従来の技術】
ＰＷＭ制御を用いて能力可変するＤＣモータにおいて、従来そのＰＷＭ信号発生回路は、三角波信号とアナログ信号をコンパレータ（比較器）に入力し、その出力信号を用いるものであった。この従来のＤＣモータを負荷装置としてポンプに用いた場合を図１１〜１７に基づいて説明する。図１１は従来のＰＷＭ信号発生回路を用いた従来のＤＣモータの駆動装置である。また図１２はスイッチング素子のＯＮ／ＯＦＦ特性図、図１３は従来のＰＷＭ信号発生回路内の第１の信号波形図、図１４は従来のＰＷＭ信号発生回路内の第２の信号波形図、図１５は従来のＰＷＭ信号発生回路内の第３の信号波形図、図１６は従来の能力信号発生手段から発生されるアナログ信号の電圧とＰＷＭ信号のデュティの関係の説明図である。また図１７は能力信号発生手段内の積分回路からの出力信号であるアナログ信号の時間変化を表す波形図である。まず図１１から説明する。
【０００３】
図１１において、１０１は直流電源、１０２は直流電源１０１から電気を給電されるモータ巻線、１０３はマグネットロータ、１０４は磁極位置検出素子である。モータ巻線１０２に電流が流れることによって発生する磁界と、マグネットロータ１０３の磁界との吸引・反発の磁力によりモータの回転トルクが発生する。この時一定回転方向に効率良く回転トルクを発生させるために、マグネットの磁極位置を検出する磁極位置検出素子１０４がモータ巻線１０２のスロット間の適当な位置に配置される。
【０００４】
１０５は通電切替回路、１０６は第１スイッチング素子群、１０７は第２スイッチング素子群である。通電切替回路１０５は磁極位置検出素子１０４の出力信号を受け、どのモータ巻線１０２のどちら方向に電流を流すと効率良く一定方向に回転トルクを発生するか判断する。第１スイッチング素子群１０６は、この通電切替回路１０５の出力信号に合わせ、モータ巻線１０２のどの端子に直流電源１０１の＋極を接続するかをスイッチし、第２スイッチング素子群１０７は、モータ巻線１０２のどの端子に直流電源１０１の−極を接続するかをスイッチする。
【０００５】
また、１０８は負荷検出手段、１０９は能力信号発生手段、１１０は駆動モータの能力を変えるための指令値となるアナログ信号である。負荷検出手段１０８は、モータの能力を制御するために、モータの負荷(この場合ポンプ)の仕事の結果（圧力もしくは流量）を検出する。能力信号発生手段１０９は、この検出信号を受け、現在の負荷の仕事の結果（圧力もしくは流量）を検知し、目標の負荷の仕事の結果（圧力もしくは流量）になるようにするものである。能力信号発生手段１０９は負荷の仕事の結果（圧力もしくは流量）を制御するため、駆動モータの能力をかえるアナログ信号１１０を出力する。実際にモータの能力を可変にするための駆動制御方法としては、第２スイッチング素子群１０７に入力する信号を生成するとき、通電切替回路１０５内でＰＷＭ信号の積をとることで第２スイッチング素子群１０７が給電期間を調整することで行われる。
【０００６】
次にこのＰＷＭ信号の発生方法を説明する。１１１はＰＷＭ信号を発生するＰＷＭ信号発生回路、１１２はＰＷＭ信号発生回路内で特定の周期（数ｋＨｚ程度）の三角波信号を発生する三角波発生回路、１１３は比較回路、１２０は三角波信号、１３８はＣＲ積分回路である。比較回路１１３は、図１２に示すように三角波発生回路１１２の出力信号である三角波信号１２０とアナログ信号１１０と電圧の比較を行い、比較回路出力信号１２１を出力する。
【０００７】
次に図１２は、スイッチング素子群１０６，１０７がＦＥＴの場合のゲート−ソース間（ＧＳ間）の電圧とドレイン−ソース間（ＤＳ間）の抵抗特性を表している。一般にＧＳ間の電圧が２〜３ＶまではＯＦＦ状態で、それから５〜６Ｖ程度まで可変抵抗状態、それ以上の電圧がＧＳ間に印可されるとＯＮ状態となり、非常に小さい抵抗値をもった特性となる。ここで注意すべきは、可変抵抗器の状態ではＦＥＴの損失が非常に大きくなり、かなり素子から発熱して、最悪時には素子の破壊をまねくことになる。またここではＦＥＴの場合の特性を表したが、バイポーラのトランジスタの場合も同様で、ベース−エミッタ間（ＢＥ間）が低い電圧では十分なベース電流を流すことができずにトランジスタでの電圧降下が大きくなり、損失が大きくなる。
【０００８】
次に図１３に基づきＰＷＭ信号発生回路１１１内の信号波形について説明する。三角波発生回路１１２の出力はほぼ対称な三角波信号１２０となる。三角波信号１２０と所定の期間一定の大きさの電圧をもつアナログ信号１１０とが、比較回路１１３に入力される。電圧の大きさを比較し、その結果ＨとＬの幅が決定され、比較回路出力信号１２１となって出力される。比較回路出力信号１２１は通電切替回路１０５において反転信号となり、この信号が第２スイッチング素子群１０７のＯＮ／ＯＦＦ信号となる。この信号が、ＰＷＭ信号１２２として駆動モータの能力を可変するものである。
【０００９】
図１３において、１２３はスイッチング素子がＯＦＦ状態と可変抵抗状態の境界のＧＳ間電圧値を表し、１２４は可変抵抗状態とＯＮ状態の境界のＧＳ間電圧値を表している。すなわち、図１３に示す場合は可変抵抗状態の期間が短く、ほとんどがＯＮかＯＦＦの状態で素子の損失が異常に増大することはない。しかし、可変抵抗状態が長いと異常な損失を招く。図１４はＰＷＭ信号のデュティが小さい時（〜数％程度）のＰＷＭ信号発生回路内の信号波形であり、図１５はＰＷＭ信号のデュティが大きい時（〜９０％以上）のＰＷＭ信号発生回路内の信号波形を示している。図１４，１５とも共通しているのは、ＰＷＭ信号１２２の可変抵抗状態の期間が長いことである。図１４の場合は、ＯＦＦ状態での素子の損失はほとんど無いが、ＯＮ状態が無く可変抵抗状態のみであり、その期間が長いとモータの起動時に十分巻線に電流が流れないため、マグネットロータが回転せず、スイッチング素子群１０６，１０７のそれぞれ1つのスイッチング素子に電流が流れ続け、これにより異常な損失が起こり、延いては素子が破壊してしまう。また図１５の場合、ＯＮ状態でかなり損失が大きい上、スイッチング時の可変抵抗の状態で異常な損失の増大を生む。つまりデュティが１００％の時より図１５の場合の方が素子に流れる電流は小さいが、素子での損失はかなり大きくなり、延いては素子が破壊してしまう。
【００１０】
次に図１６に基づいてアナログ信号１１０とＰＷＭデュティの関係をそれぞれ説明する。ＰＷＭ信号発生回路１１１として三角波信号１２０を使用する場合、アナログ信号とＰＷＭデュティは直線１２５で示すようにリニアな関係となる。目標のＰＷＭデュティが決定された場合は、アナログ信号１１０の大きさもこの直線１２５が表す簡単な式で一意的に決定される。また同じ大きさのアナログ信号のステップであれば、ＰＷＭデュティのステップの大きさも同じになる。そして、モータの起動時や能力を上昇させるときなど、モータの能力を決定するＰＷＭ信号のデュティの変化量を過度に大きくする場合においてもスイッチング素子群（ＦＥＴ等）に過渡的に大電流が流れることを防止するため、能力信号発生手段１０９内にその出力信号であるアナログ信号の時間変化量を制限するためのコンデンサＣと抵抗器Ｒから構成されるＣＲ積分回路１３８を内蔵している。
【００１１】
また図１７に積分回路１３８を通過したアナログ信号の時間変化を表している。最も過渡的にスイッチング素子群（ＦＥＴ等）に電流が流れやすいのはモータ起動時であり、起動時にアナログ信号の時間変化量をＣＲ積分回路１３８の定数Ｃ，Ｒで決定した場合のアナログ信号１１０ａに表している。起動指令直後から充電開始し、三角波発生回路１１２の三角波信号１２０の下限値を越えた時点でＰＷＭ信号が発生し、モータ巻線１０２に通電が開始される。アナログ信号１１０ａをみて分かるように、通常の充放電回路（ＣＲ回路）では充電開始（起動指令）点で最もｄＶ／ｄｔ（傾き）が最も大きく、電圧が大きいほど傾きが小さくなる特徴を持つ。
【００１２】
【発明が解決しようとする課題】
しかしながら従来の方法では、ＰＷＭのデュティがある下限値以下のときや、ある上限値以上（１００％は除く）のとき、図１４でも分かるようにスイッチング時に過渡的な状態でスイッチング素子群（ＦＥＴ等）が完全にＯＮしない状態が発生し、スイッチング素子群（ＦＥＴ等）での損失が急激に上昇する。これにより、効率の低下が起こり、最終的には部品の破壊も発生してしまう。このための対策として十分余裕をもった部品を使ったり、温度上昇を抑えるために大きな放熱器を取りつける必要が生じる。これによって小型・低価格のモータが提供できないという課題を有していた。
【００１３】
さらにモータの起動時や負荷の増加に応じて能力を上昇するとき、過渡的に電流がスイッチング素子群（ＦＥＴ等）に異常に流れないようにするＣＲ回路を用いた従来のソフトスタートの方法では、ＰＷＭ信号発生開始時点でのアナログ信号のｄＶ／ｄｔを固定的に設定するため、モータの能力を急激に変えたい場合に対応できず、制御性の悪化をもたらすという課題を有していた。
【００１４】
そこで本発明は、スイッチング素子群の可変抵抗の状態となる期間を低減し、効率のよい、安価で、制御性の高い、ＤＣモータの駆動制御装置を提供することを目的とする。
【００１５】
【課題を解決するための手段】
この課題を解決するために本発明のＤＣモータの駆動制御装置は、ＤＣモータを駆動する複数相のモータ駆動コイルと、当該モータ駆動コイルに給電する直流電源の＋極と前記各モータ駆動コイルとの間にそれぞれ挿入されたスイッチング素子からなる第１スイッチング素子群と、前記直流電源の−極と前記各モータ駆動コイルとの間にそれぞれ挿入されたスイッチング素子からなる第２スイッチング素子群と、回転子の磁極位置を検出する複数個の磁極位置検出素子と、前記磁極位置検出素子の出力信号に基づいて前記第１スイッチング素子群および前記第２スイッチング素子群を制御し前記直流電源から給電する前記モータ駆動コイルを切換える通電切替え回路と、前記ＤＣモータの負荷装置の仕事の結果に応じた電圧値のアナログ信号を発生する能力信号発生手段と、前記第２スイッチング素子群のスイッチング素子のＯＮ／ＯＦＦ信号となるＰＷＭ信号を出力して前記直流電源から前記モータ駆動コイルへの給電量を調整するＰＭＷ信号発生回路とを備え、前記ＰＷＭ信号発生回路は、ＰＭＷ信号を出力するにあたってはＰＭＷ信号のデュティを入力された前記アナログ信号の電圧値に応じた値に設定するＤＣモータの駆動制御装置において、前記能力信号発生手段のアナログ信号の電圧値を監視し、該電圧値がＰＷＭ信号のデュティ指定範囲の上下限にそれぞれ対応する上限値と下限値になったことを示す信号を出力する電圧監視手段と、前記電圧監視手段の出力信号を受けて、前記アナログ信号の電圧値が前記上限値を越えたときは前記アナログ信号の電圧値を第１電圧に変換してＰＷＭ信号発生回路に出力し、前記アナログ信号の電圧値が前記下限値より下がったときは前記アナログ信号の電圧値を第２電圧に変換してＰＷＭ信号発生回路に出力し、前記アナログ信号の電圧値が前記上限値以下前記下限値以上であるときは電圧値を変換せずに前記アナログ信号をＰＷＭ信号発生回路に出力する信号変換手段とを備え、前記第１電圧は、ＰＷＭ信号のデュティを１００％とする電圧値であり、前記第２電圧は、ＰＷＭ信号のデュティを０％とする電圧値であることを特徴とする。
【００１６】
これにより、スイッチング素子群の可変抵抗の状態となる期間を低減し、効率のよい、安価で、制御性の高い、ＤＣモータの駆動制御装置とすることができる。
【００１７】
【発明の実施の形態】
本発明の請求項１に記載された発明は、ＤＣモータを駆動する複数相のモータ駆動コイルと、当該モータ駆動コイルに給電する直流電源の＋極と前記各モータ駆動コイルとの間にそれぞれ挿入されたスイッチング素子からなる第１スイッチング素子群と、前記直流電源の−極と前記各モータ駆動コイルとの間にそれぞれ挿入されたスイッチング素子からなる第２スイッチング素子群と、回転子の磁極位置を検出する複数個の磁極位置検出素子と、前記磁極位置検出素子の出力信号に基づいて前記第１スイッチング素子群および前記第２スイッチング素子群を制御し前記直流電源から給電する前記モータ駆動コイルを切換える通電切替え回路と、前記ＤＣモータの負荷装置の仕事の結果に応じた電圧値のアナログ信号を発生する能力信号発生手段と、前記第２スイッチング素子群のスイッチング素子のＯＮ／ＯＦＦ信号となるＰＷＭ信号を出力して前記直流電源から前記モータ駆動コイルへの給電量を調整するＰＭＷ信号発生回路とを備え、前記ＰＷＭ信号発生回路は、ＰＭＷ信号を出力するにあたってはＰＭＷ信号のデュティを入力された前記アナログ信号の電圧値に応じた値に設定するＤＣモータの駆動制御装置において、前記能力信号発生手段のアナログ信号の電圧値を監視し、該電圧値がＰＷＭ信号のデュティ指定範囲の上下限にそれぞれ対応する上限値と下限値になったことを示す信号を出力する電圧監視手段と、前記電圧監視手段の出力信号を受けて、前記アナログ信号の電圧値が前記上限値を越えたときは前記アナログ信号の電圧値を第１電圧に変換してＰＷＭ信号発生回路に出力し、前記アナログ信号の電圧値が前記下限値より下がったときは前記アナログ信号の電圧値を第２電圧に変換してＰＷＭ信号発生回路に出力し、前記アナログ信号の電圧値が前記上限値以下前記下限値以上であるときは電圧値を変換せずに前記アナログ信号をＰＷＭ信号発生回路に出力する信号変換手段とを備え、前記第１電圧は、ＰＷＭ信号のデュティを１００％とする電圧値であり、前記第２電圧は、ＰＷＭ信号のデュティを０％とする電圧値であることを特徴とするＤＣモータの駆動制御装置であるから、ＰＷＭ信号のデュティの可変範囲（０〜１００％）の中の所定のデュティ指定範囲外で電圧を指定でき、時間的な変化量（ｄＶ／ｄｔ）を管理することができる。
【００１８】
また、スイッチング素子群の可変抵抗状態の期間が長い状態で使用することを禁止し、スイッチング素子群の異常発熱を低減し、安価で小型のモータ駆動装置を提供できる。
【００１９】
本発明の請求項２に記載された発明は、ＤＣモータを駆動する複数相のモータ駆動コイルと、当該モータ駆動コイルに給電する直流電源の＋極と前記各モータ駆動コイルとの間にそれぞれ挿入されたスイッチング素子からなる第１スイッチング素子群と、前記直流電源の−極と前記各モータ駆動コイルとの間にそれぞれ挿入されたスイッチング素子からなる第２スイッチング素子群と、回転子の磁極位置を検出する複数個の磁極位置検出素子と、前記磁極位置検出素子の出力信号に基づいて前記第１スイッチング素子群および前記第２スイッチング素子群を制御し前記直流電源から給電する前記モータ駆動コイルを切換える通電切替え回路と、前記ＤＣモータの負荷装置の仕事の結果に応じた電圧値のアナログ信号を発生する能力信号発生手段と、前記第２スイッチング素子群のスイッチング素子のＯＮ／ＯＦＦ信号となるＰＷＭ信号を出力して前記直流電源から前記モータ駆動コイルへの給電量を調整するＰＭＷ信号発生回路とを備え、前記ＰＷＭ信号発生回路は、ＰＭＷ信号を出力するにあたってはＰＭＷ信号のデュティを入力された前記アナログ信号の電圧値に応じた値に設定するＤＣモータの駆動制御装置において、前記能力信号発生手段のアナログ信号の電圧値を監視し、該電圧値がＰＷＭ信号のデュティ指定範囲の上下限にそれぞれ対応する上限値と下限値になったことを示す信号を出力する電圧監視手段と、前記電圧監視手段の出力信号を受けて、前記アナログ信号の電圧値が前記上限値を越えたときは前記ＰＷＭ信号発生回路が出力するＰＭＷ信号のデュティを１００％に変換し、前記アナログ信号の電圧値が前記下限値より下がったときは前記ＰＷＭ信号発生回路が出力するＰＭＷ信号のデュティを０％に変換し、前記アナログ信号の電圧値が前記上限値以下前記下限値以上であるときは前記ＰＷＭ信号発生回路に出力するＰＭＷ信号のデュティを変換しない信号変換手段とを備えたことを特徴とするＤＣモータの駆動制御装置であるから、ＰＷＭ信号の所定のデュティ指定範囲外でデュティを指定でき、ＰＷＭ信号の時間変化量を管理することができ、応答性のよいモータ駆動装置を提供できる。
【００２０】
本発明の請求項３に記載された発明は、請求項１または２において、１相の誘起電圧をＶ^＊、給電用電源電圧をＶ、巻線に印加される電圧をＶ_１、モータ起動時の許容初期デュティをＤ_ｍｉｎ(％)、βを係数（β＝１．３５〜１．５５）としたとき、Ｖ_１＝Ｖ−β×Ｖ^＊であり、ＰＷＭ信号のデュティの最大変化量Ｄ_ｍａｘ（％）が、Ｄ_ｍａｘ＝Ｄ_ｍｉｎ＋Ｄ_ｍｉｎ×（β×Ｖ^＊／Ｖ_１）で与えられ、ＰＷＭ信号のデュティ指定範囲の上限をＤ_ｍａｘ（％）、下限をＤ_ｍｉｎ(％)に設定したことを特徴とするＤＣモータの駆動制御装置であるから、起動時にスイッチング素子群に流れる電流を制限し、部品の破壊を防止するとともに、応答性のよいＤＣモータの駆動装置を提供できる。
【００２１】
（実施の形態１）
以下、本発明の実施の形態１におけるモータの駆動制御装置について説明する。図１は本発明の実施の形態１におけるモータの駆動制御装置の構成図である。従来の技術と同一符号にものについては説明を割愛する。１０１は直流電源、１０２は直流電源１０１から電気を給電されるモータ巻線（本発明のモータ駆動コイル）、１０３はマグネットロータ、１０４は磁極位置検出素子である。１０５は通電切替回路、１０６は第１スイッチング素子群、１０７は第２スイッチング素子群である。１０８は負荷検出手段、１０９は能力信号発生手段、１１０は駆動モータの能力を変える指令値となるアナログ信号である。１１１はモータ巻線１０２への給電指令をパルス幅と比例させたＰＷＭ信号を発生するＰＷＭ信号発生回路、１１２はＰＷＭ信号発生回路内で特定の周期（数ｋＨｚ程度）の三角波信号を発生する三角波発生回路、１１３は比較回路、１２０は三角波信号、１３８はＣＲ積分回路である。
【００２２】
１５０は電圧の大きさを監視する電圧監視手段、１５１はその電圧監視検出信号、１５２は電圧監視検出信号１５１を受け取る信号変換手段である。
【００２３】
負荷検出手段１０８の検出信号を受け、現在の負荷の仕事の結果（負荷がポンプであれば圧力もしくは流量）を検知し、目標の負荷の仕事の結果（圧力もしくは流量）になるように能力信号発生手段１０９から駆動モータの能力をかえるアナログ信号１１０を出力する。
【００２４】
このアナログ信号１１０は、電圧の大きさを監視する電圧監視手段１５０に入力され、電圧監視手段１５０が電圧の大きさが設定された下限値以下、または設定された上限値以上かを判断する。判断された結果の電圧監視検出信号１５１は信号変換手段１５２に入力される。さらに、この信号変換手段１５２にはアナログ信号１１０が直接能力信号発生手段１０９から入力される。信号変換手段１５２によって変換後の信号は、変換されたアナログ信号１１０^*として、ＰＷＭ信号発生回路１１１に入力される。
【００２５】
次に図２，３を用いて本発明の実施の形態１の電圧監視手段１５０について説明する。図２，３は電圧監視手段１５０のそれぞれ別の形態である。図２は本発明の実施の形態１におけるＦＥＴを用いた電圧監視装置の構成図である。図２において、１５０ａは出力信号を反転させるインバータ、１５３はアナログ信号１１０の下限値または上限値となる設定電圧、１５４はスイッチ手段であるＦＥＴ、１５５，１５６は抵抗器である。この図２の形態の電圧監視手段１５０は、能力信号発生手段１０９で発生した出力のアナログ信号１１０に対してＦＥＴ１５４を用い、アナログ信号１１０の大きさでＯＮ／ＯＦＦさせるものである。アナログ信号１１０の設定電圧１５３、抵抗器１５５，１５６の抵抗値の大きさ、ＦＥＴ１５４のＯＮするゲート−ソース間の電圧、電源＋ＰＷＲの大きさという４つの要素に従ってＦＥＴ１５４がＯＮ／ＯＦＦする。本実施の形態においては設定電圧１５３よりアナログ信号１１０が大きいときＬｏｗを出力するようにインバータ１５０ａで信号反転されて、電圧監視検出信号１５１が出力される。
【００２６】
次に、図３は本発明の実施の形態１におけるコンパレータを用いた電圧監視装置の構成図である。図３において、１５７はコンパレータである。本実施の形態では能力信号発生手段１０９の出力であるアナログ信号１１０をこのコンパレータ１５７の−極に接続し、設定電圧１５３と同等の電圧値を設定した分圧抵抗による信号を＋極に接続することで、アナログ信号１１０が下限値もしくは上限値となる設定電圧１５３より大きくなったとき、コンパレータ１５７の電圧監視検出信号１５１がＬｏｗになって出力されるものである。
【００２７】
次に図４を用いて本発明の実施の形態１における信号変換手段について説明する。図４は本発明の実施の形態１におけるＤＣモータの駆動制御装置の能力信号発生手段の出力を変換する信号変換手段の説明図である。
【００２８】
図４において、１５１ａ，１５１ｂは電圧監視手段１５０の許容電圧監視検出信号、１５３ａはデュティ指定範囲におけるアナログ信号１１０の下限値、１５３ｂはデュティ指定範囲におけるアナログ信号１１０の上限値、１５８は１倍バッファアンプである。能力信号発生手段１０９の出力は下限値１５３ａと上限値１５３ｂでＯＮ／ＯＦＦされ、電圧監視手段１５０から２つに許容電圧監視検出信号１５１ａ，１５１ｂが出力される。信号変換手段１５２では、下限値１５３ａに対応した許容電圧監視検出信号１５１ａはＮ型のトランジスタのベースに接続され、上限値１５３ｂに対応した許容電圧監視検出信号１５１ｂはＰ型のトランジスタのベースが接続される。Ｎ型とＰ型の２つのトランジスタはトーテンポールで接続され、１つの出力信号として出力される。この出力信号は、能力信号発生手段１０９からのアナログ信号１１０が１倍バッファアンプ１５８を通過した信号と接続され、その重畳された信号が信号変換手段１５２の出力信号（変換後のアナログ信号１１０^*）として出力される。この変換後のアナログ信号１１０^*は図４のように、下限値１５３ａから上限値１５３ｂまでアナログ信号１１０と同じ値となるが、下限の設定値１５３ａ以下ではＬｏｗ（ＰＷＭ信号のデュティが０％となる値）の電圧（本発明の第２電圧）となり、上限の設定値１５３ｂ以上ではＨｉｇｈ（ＰＷＭ信号のデュティが１００％となる値）の電圧（本発明の第１電圧）となる。
【００２９】
続いて図７に基づいて、本発明の実施の形態１における変換前のアナログ信号１１０とＰＷＭデュティの関係曲線１２６について説明する。図７は本発明の実施の形態１における変換前のアナログ信号とＰＷＭデュティの関係の説明図である。信号変換手段１５２が能力信号発生手段１０９のアナログ信号１１０を受ける位置に設けられているため、ＰＷＭ信号発生回路１１１に入力される変換後のアナログ信号１１０^*は、下限値と上限値で２ヶ所ステップ的に電圧値が変化する。なお、図７においてはＰＷＭデュティもこの２ヶ所でステップ的に変化するため、変換前のアナログ信号１１０が、下限値以下ではデュティは０％、上限値以上ではデュティは１００％になることを示している。本実施の形態１においてはデュティ指定範囲をスイッチング素子群の発熱防止という側面から決定したが、他の側面から目的に応じたデュティ指定範囲を指定することができる。
【００３０】
（実施の形態２）
以下、本発明の実施の形態２におけるモータの駆動制御装置について説明する。実施の形態２のモータの駆動制御装置は、信号変換手段をＰＷＭ信号発生回路の出力を受ける位置に配置したことを特徴としている。実施の形態１のモータの駆動制御装置と同一符号は同一内容であるから、図２，３を参照するとともに詳細な説明は省略する。
【００３１】
図５は本発明の実施の形態２におけるモータの駆動制御装置の構成図、図６は本発明の実施の形態２におけるモータの駆動制御装置の信号変換手段の説明図である。図５，６において、１０１は直流電源、１０２はモータ巻線、１０３はマグネットロータ、１０４は磁極位置検出素子、１０５は通電切替回路、１０６は第１スイッチング素子群、１０７は第２スイッチング素子群である。１０８は負荷検出手段、１０９は能力信号発生手段、１１０はアナログ信号である。１１１はＰＷＭ信号を発生するＰＷＭ信号発生回路、１１２は三角波発生回路、１１３は比較回路、１２０は三角波信号、１３８はＣＲ積分回路である。１５０は電圧監視手段、１５１は電圧監視検出信号、１５２は信号変換手段である。
【００３２】
実施の形態２のモータの駆動制御装置も負荷検出手段１０８の検出信号を受け、現在の負荷の仕事の結果（負荷がポンプであれば圧力もしくは流量）を検知し、目標の負荷の仕事の結果（圧力もしくは流量）になるように能力信号発生手段１０９から駆動モータの能力を変えるアナログ信号１１０を出力する。
【００３３】
このアナログ信号１１０は、電圧の大きさを監視する電圧監視手段１５０に入力され、電圧監視手段１５０が電圧の大きさが設定された下限値以下、または設定された上限値以上かを判断する。判断された結果の電圧監視検出信号１５１は信号変換手段１５２に入力される。さらに、この信号変換手段１５２にはＰＷＭ信号発生回路１１１の比較回路出力信号１２１が入力される。この比較回路出力信号１２１は、能力信号発生手段１０９から出力されたアナログ信号１１０と三角波発生回路１１２から出力された三角波信号１２０とを比較回路１１３で比較して得られたものである。信号変換手段１５２によって変換後の信号は、比較回路出力信号１２１^*として通電切替回路１０５に入力される。
【００３４】
次に図２，３を用いて本発明の実施の形態２の電圧監視手段１５０について説明する。図２は実施の形態２におけるＦＥＴを用いた電圧監視装置を示す。図２において、１５０ａはインバータ、１５３は設定電圧、１５４はＦＥＴ、１５５，１５６は抵抗器である。設定電圧１５３よりアナログ信号１１０が大きい時Ｌｏｗになるようにインバータ１５０ａで信号反転されて、電圧監視検出信号１５１となり出力される。
【００３５】
次に、図３は実施の形態２におけるコンパレータを用いた電圧監視装置を示している。図３において、１５７はコンパレータである。アナログ信号１１０が下限値もしくは上限値１５３より大きくなったとき、コンパレータ１５７の電圧監視検出信号１５１がＬｏｗになって出力される。
【００３６】
次に図６を用いて本発明の実施の形態２における信号変換手段について説明する。図６において、電圧監視手段１５０の出力信号については実施の形態１と同様であり、説明を省略する。図６において、１５９，１６０はフォトカプラである。能力信号発生手段１０９の出力であるアナログ信号１１０がＰＷＭ信号発生回路１１１に入力され、アナログ信号１１０の大きさに応じてデュティの大きさが決定され、比較回路出力信号１２１としてＰＷＭ信号発生回路１１１から出力される。
【００３７】
一方信号変換手段１５２は、電圧監視手段１５０からの下限値を示す許容電圧監視検出信号１５１ａと、上限値を示す許容電圧監視検出信号１５１ｂを受け、それぞれバッファを通し、その出力信号がそれぞれフォトカプラ１５９，１６０の１次側に接続される。その後フォトカプラ１５９，１６０の２次側が図６のようにトーテンポールで接続されるとともに、比較回路出力信号１２１も接続された形で信号変換手段１５２の出力信号となり、変換された比較回路出力信号１２１^*として出力される。この変換された比較回路出力信号１２１^*は、下限のデュティ及び上限のデュティまでは連続して選択可能であるが、下限値以下ではデュティ０％となり、上限値以上ではデュティ１００％となる。
【００３８】
続いて本発明の実施の形態２における変換前のアナログ信号１１０とＰＷＭデュティの関係曲線１２６について説明する。信号変換手段１５２がＰＷＭ信号発生回路１１１の比較回路出力信号１２１を受けるとともに電圧監視検出信号１５１も受けているため、比較回路出力信号１２１は、下限値以下と上限値以上の２ヶ所で電圧監視検出信号１５１をトリガとしてＨｉｇｈとＬｏｗになる電圧が印加されステップ的にデュティが変化する。変換前のアナログ信号１１０が、下限値以下ではデュティは０％、上限値以上ではデュティは１００％になる。
【００３９】
（実施の形態３）
次に図８，９，１０を用いて、本発明の実施の形態３におけるＰＷＭデュティの変化量を制御するモータの駆動制御装置について説明する。図８は本発明の実施の形態３における３相モータの電気回路図で、図９は本発明の実施の形態３における３相ブラシレモータの誘起電圧の２相分の合成電圧波形図、図１０は本発明の実施の形態３におけるＰＷＭデュティの変化の状態図である。
【００４０】
まず図８において、１４０Ｕ，１４０Ｖ，１４０ＷはそれぞれＵ相，Ｖ相，Ｗ相の誘起電圧、１４１Ｕ，１４１Ｖ，１４１ＷはそれぞれＵ相，Ｖ相，Ｗ相のインダクタンス成分、１４２Ｕ，１４２Ｖ，１４２ＷはそれぞれＵ相，Ｖ相，Ｗ相の抵抗成分、１４３Ｕ，１４３Ｖ，１４３ＷはそれぞれＵ相，Ｖ相，Ｗ相の端子である。３相ブラシレスモータの各相の巻線にはマグネットロータ１０３が回転することにより誘起電圧１４０Ｕ，１４０Ｖ，１４０Ｗが発生するとともに、各巻線は電気回路上インダクタンス成分１４１Ｕ，１４１Ｖ，１４１Ｗと抵抗成分１４２Ｕ，１４２Ｖ，１４２Ｗをもつことを示している。とくに３相ＤＣモータの一般的駆動方法である１２０度通電方式では、各巻線で誘起電圧１４０Ｕ，１４０Ｖ，１４０Ｗうち大きい２相の端子１４３Ｕ，１４３Ｖ，１４３Ｗに電源電圧を印加するように、第１スイッチング素子群１０６の内1つの素子と、第２スイッチング素子群１０７の内1つの素子がＯＮする。
【００４１】
次に図９において、１４４は１２０度通電方式で相切替区間の1つの区間（通電する２相が他の１相より誘起電圧が大きい期間）の波形、１４５は電源電圧、１４６は相切替直後に巻線にかかる電圧である。すなわち図９の拡大図に示しているのは、通電する２相１４０Ｕ，１４０Ｖが他の１相１４０Ｗより誘起電圧が大きい区間であり、1相の誘起電圧の大きさをＶ^*とすると、２相分の誘起電圧の大きさは波形１４４に示すように１．５Ｖ^*から１．７Ｖ^*の間を変動する。相切替のタイミングを少し進ませると、進角させることで相切替直後に巻線にかかる電圧１４６は大きくなる。すなわちこの巻線にかかる電圧１４６は図８の斜線部分で示され、電源電圧１４５から２相分の誘起電圧の合成（波形１４４）を差し引いた電圧Ｖ₁である。また進角させることで２相の誘起電圧の合成電圧が最も大きいときに電流も十分流れるため、モータの最大出力が得られる特徴がある。
【００４２】
ところで誘起電圧Ｖ^*は、
Ｖ^*＝α・Ｎ
ここでα（V/rpm）は係数（モータごとに決まる誘起電圧定数）、Ｎ（rpm）は回転数である。従って巻線にかかる電圧１４６は、回転数が低い起動時にはＶ^*が小さくなるためこのとき最も大きくなる。これによって起動時に流れる電流を押さえるために最小のＰＷＭデュティ（Ｄ_min（％））を設定することができる。
【００４３】
次に図１０において、１１０ａはＣＲ積分回路でアナログ信号の変化量を制限したときのＰＷＭデュティの時間変化曲線、１４７はデュティの許容最大変化量Ｄ_max（％）を算出したときのＰＷＭデュティの時間変化曲線である。能力信号発生手段１０９とＰＷＭ信号発生回路１１１をマイコン（中央処理装置）で構成したときには、マイコンから直接ＰＷＭ信号が出力される。なおこの場合、図示しないメモリからマイコンに制御プログラムがロードされ、能力信号発生手段１０９が機能実現手段として構成される。同様にＰＷＭ信号発生回路１１１もメモリから制御プログラムがロードされ、マイコン上の機能実現手段として構成される。マイコン入力して設定すれば、ＰＷＭ信号のデュティの変化量も自由に制御できる。
【００４４】
ところで、実施の形態３においては、以下のような式でＰＷＭ信号のデュティの許容最大変化量Ｄ_max（％）を設定する。
【００４５】
Ｄ_max＝Ｄ_min＋Ｄ_min×（β×Ｖ^*／Ｖ₁）
βは係数（相切替の進角に依存し、β＝１．３５〜１．５５）、D_min(％)はモータ起動時の許容初期デュティである。なお、１２０度通電方式ではＶ₁＝Ｖ−β×Ｖ^*があり、起動時のＰＭＷ信号のデュティＤ_minとＤ_maxの間にＤ_max／Ｄ_min＝Ｖ／（Ｖ−β×Ｖ^*）の関係が成り立つことから、上式は導かれるものである。誘起電圧Ｖ^*は上述したように回転数Ｎに比例することから、磁極位置検出素子１０４の検出信号から回転数信号の周期を計測して回転数を算出し、その結果と係数αの積をとって誘起電圧Ｖ^*を求めればよい。
【００４６】
実施の形態３の駆動制御装置は、この許容最大変化量Ｄ_max（％）を計算し、実施の形態１，２の駆動制御装置において、ＰＷＭ信号の上限値をＤ_max（％）、下限値をＤ_min(％)として設定するものである。この駆動制御装置によって起動したときのＰＷＭデュティの時間変化曲線１４７は、図１０に示すようにきわめて速い立ち上がりを示している。すなわち、デュティ上昇時にその最大変化量Ｄ_max（％）を制限することで、過渡的に流れる電流を抑え、スイッチング素子へのストレスを軽減することができる。従来のＣＲ積分回路でアナログ信号の変化量を制限した時間変化曲線１１０ａは緩慢な応答であり、本発明の実施の形態３の駆動装置の方が従来のＣＲ積分回路より明らかに制御の応答性がよいことが分かる。
【００４７】
【発明の効果】
以上のように本発明のモータの駆動制御装置によれば、スイッチング素子群を可変抵抗の状態となる期間を低減し、効率のよい、安価な、小型のモータ駆動装置を提供できる。またデュティ上昇時にその最大変化量Ｄ_max（％）を制限することで、過渡的に流れる電流を抑え、スイッチング素子へのストレスを軽減するとともに、その範囲内での制御の応答性を最大限に向上できるモータ駆動装置を提供できる。
【図面の簡単な説明】
【図１】本発明の実施の形態１におけるモータの駆動制御装置の構成図
【図２】本発明の実施の形態１におけるＦＥＴを用いた電圧監視装置の構成図
【図３】本発明の実施の形態１におけるコンパレータを用いた電圧監視装置の構成図
【図４】本発明の実施の形態１におけるＤＣモータの駆動制御装置の能力信号発生手段の出力を変換する信号変換手段の説明図
【図５】本発明の実施の形態２におけるモータの駆動制御装置の構成図
【図６】本発明の実施の形態２におけるモータの駆動制御装置の信号変換手段の説明図
【図７】本発明の実施の形態１における変換前のアナログ信号とＰＷＭデュティの関係の説明図
【図８】本発明の実施の形態３における３相モータの電気回路図
【図９】本発明の実施の形態３における３相ブラシレスモータの誘起電圧の２相分の合成電圧波形図
【図１０】本発明の実施の形態３におけるＰＷＭデュティの変化の状態図
【図１１】従来のＰＷＭ信号発生回路を用いた従来のＤＣモータの駆動装置の構成図
【図１２】スイッチング素子のＯＮ／ＯＦＦ特性図
【図１３】従来のＰＷＭ信号発生回路内の第１の信号波形図
【図１４】従来のＰＷＭ信号発生回路内の第２の信号波形図
【図１５】従来のＰＷＭ信号発生回路内の第３の信号波形図
【図１６】従来の能力信号発生手段から発生されるアナログ信号の電圧とＰＷＭ信号のデュティの関係の説明図
【図１７】能力信号発生手段内の積分回路からの出力信号であるアナログ信号の時間変化を表す波形図
【符号の説明】
１０１直流電源
１０２モータ巻線
１０３マグネットロータ
１０４磁極位置検出素子
１０５通電切替回路
１０６第１スイッチング素子群
１０７第２スイッチング素子群
１０８負荷検出手段
１０９能力信号発生手段
１１０アナログ信号
１１０^* 信号変換後の指令アナログ電圧
１１０ａＰＷＭ信号のデュティの時間変化曲線
１１１ＰＷＭ信号発生回路
１１２三角波発生回路
１１３比較回路
１２０三角波信号
１２１比較回路出力信号
１２１^* 信号変換後の比較回路出力信号
１２２ＰＷＭ信号
１２３スイッチング素子のＯＦＦと可変抵抗状態の境界のＧＳ間電圧値
１２４スイッチング素子のＯＮと可変抵抗状態の境界のＧＳ間電圧値
１２５直線
１２６ＰＷＭデュテイの関係曲線
１３８ＣＲ積分回路
１４０Ｕ，１４０Ｖ，１４０Ｗ誘起電圧
１４１Ｕ，１４１Ｖ，１４１ＷＵ，Ｖ，Ｗ相のインダクタンス成分
１４２Ｕ，１４２Ｖ，１４２ＷＵ，Ｖ，Ｗ相の抵抗成分
１４３Ｕ，１４３Ｖ，１４３ＷＵ，Ｖ，Ｗ相の端子
１４４通電する２相の誘起電圧の合成波形
１４５電源電圧
１４６巻線にかかる電圧
１４７デュティの時間変化曲線
１５０電圧監視手段
１５０ａインバータ
１５１電圧監視検出信号
１５１ａ，１５１ｂ許容電圧監視検出信号
１５２信号変換手段
１５３設定電圧
１５３ａ下限値
１５３ｂ上限値
１５４ＦＥＴ
１５５抵抗器
１５６抵抗器
１５７コンパレータ
１５８１倍バッファアンプ
１５９フォトカプラ
１６０フォトカプラ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a drive control device for a DC motor that is used in home appliances such as an air conditioner and a water heater, and whose capacity is variable by efficient PWM control.
[0002]
[Prior art]
In a DC motor whose capacity is variable using PWM control, the PWM signal generation circuit conventionally inputs a triangular wave signal and an analog signal to a comparator (comparator) and uses the output signal. The case where this conventional DC motor is used for a pump as a load device will be described with reference to FIGS. FIG. 11 shows a conventional DC motor driving apparatus using a conventional PWM signal generating circuit. 12 is an ON / OFF characteristic diagram of the switching element, FIG. 13 is a first signal waveform diagram in the conventional PWM signal generation circuit, and FIG. 14 is a second signal waveform diagram in the conventional PWM signal generation circuit. 15 is a third signal waveform diagram in the conventional PWM signal generating circuit, and FIG. 16 is an explanatory diagram of the relationship between the voltage of the analog signal generated from the conventional capability signal generating means and the duty of the PWM signal. FIG. 17 is a waveform diagram showing a time change of an analog signal which is an output signal from the integrating circuit in the capability signal generating means. First, FIG. 11 will be described.
[0003]
In FIG. 11, 101 is a DC power source, 102 is a motor winding supplied with electricity from the DC power source 101, 103 is a magnet rotor, and 104 is a magnetic pole position detecting element. The rotational torque of the motor is generated by the magnetic force of attraction and repulsion between the magnetic field generated by the current flowing through the motor winding 102 and the magnetic field of the magnet rotor 103. At this time, a magnetic pole position detecting element 104 for detecting the magnetic pole position of the magnet is disposed at an appropriate position between the slots of the motor winding 102 in order to efficiently generate rotational torque in a constant rotational direction.
[0004]
Reference numeral 105 denotes an energization switching circuit, 106 denotes a first switching element group, and 107 denotes a second switching element group. The energization switching circuit 105 receives the output signal of the magnetic pole position detection element 104, and determines which direction of which motor winding 102 the current is to flow to efficiently generate the rotational torque in a certain direction. The first switching element group 106 switches which terminal of the motor winding 102 is connected to the positive pole of the DC power supply 101 in accordance with the output signal of the energization switching circuit 105. The second switching element group 107 It is switched which terminal of the winding 102 is connected to the negative pole of the DC power source 101.
[0005]
Reference numeral 108 denotes a load detection means, 109 denotes a capability signal generation means, and 110 denotes an analog signal serving as a command value for changing the capability of the drive motor. The load detection means 108 detects the work result (pressure or flow rate) of the motor load (in this case, the pump) in order to control the motor capacity. The capability signal generating means 109 receives this detection signal, detects the work result (pressure or flow rate) of the current load, and makes it become the work result (pressure or flow rate) of the target load. The capability signal generator 109 outputs an analog signal 110 that changes the capability of the drive motor in order to control the work result (pressure or flow rate) of the load. As a drive control method for actually making the motor capacity variable, the second switching element is obtained by taking the product of the PWM signal in the energization switching circuit 105 when generating a signal to be input to the second switching element group 107. This is performed by the group 107 adjusting the power supply period.
[0006]
Next, a method for generating this PWM signal will be described. 111 is a PWM signal generating circuit that generates a PWM signal, 112 is a triangular wave generating circuit that generates a triangular wave signal having a specific period (about several kHz) in the PWM signal generating circuit, 113 is a comparison circuit, 120 is a triangular wave signal, and 138 is CR integration circuit. As shown in FIG. 12, the comparison circuit 113 compares the voltage of the triangular wave signal 120, which is the output signal of the triangular wave generation circuit 112, with the analog signal 110, and outputs a comparison circuit output signal 121.
[0007]
Next, FIG. 12 shows the gate-source voltage (between GS) voltage and the drain-source (between DS) resistance characteristics when the switching element groups 106 and 107 are FETs. In general, the voltage between GS is in the OFF state until 2 to 3V, then it is in the variable resistance state until about 5 to 6V, and when it is applied between GS, it is in the ON state and has a very small resistance value. It becomes. It should be noted that the loss of the FET becomes very large in the state of the variable resistor, and heat is considerably generated from the element, and in the worst case, the element is destroyed. In addition, although the characteristics in the case of the FET are shown here, the same applies to the case of the bipolar transistor. If the voltage between the base and the emitter (between BE) is low, a sufficient base current cannot flow, and the voltage drop in the transistor. Increases and loss increases.
[0008]
Next, a signal waveform in the PWM signal generation circuit 111 will be described with reference to FIG. The output of the triangular wave generating circuit 112 is a substantially symmetrical triangular wave signal 120. The triangular wave signal 120 and the analog signal 110 having a constant voltage for a predetermined period are input to the comparison circuit 113. The magnitudes of the voltages are compared, and as a result, the widths of H and L are determined and output as a comparison circuit output signal 121. The comparison circuit output signal 121 becomes an inverted signal in the energization switching circuit 105, and this signal becomes the ON / OFF signal of the second switching element group 107. This signal is used as the PWM signal 122 to vary the capability of the drive motor.
[0009]
In FIG. 13, reference numeral 123 denotes a voltage value between GS at the boundary between the OFF state and the variable resistance state, and reference numeral 124 denotes a voltage value between GS at the boundary between the variable resistance state and the ON state. That is, in the case shown in FIG. 13, the period of the variable resistance state is short, and the loss of the element does not increase abnormally when it is mostly ON or OFF. However, if the variable resistance state is long, an abnormal loss is caused. 14 shows a signal waveform in the PWM signal generation circuit when the duty of the PWM signal is small (˜about several percent), and FIG. 15 shows the inside of the PWM signal generation circuit when the duty of the PWM signal is large (˜90% or more). The signal waveform is shown. What is common to FIGS. 14 and 15 is that the period of the variable resistance state of the PWM signal 122 is long. In the case of FIG. 14, there is almost no loss of the element in the OFF state, but there is no ON state and only the variable resistance state. If the period is long, sufficient current does not flow through the winding when the motor is started. Does not rotate, and a current continues to flow through one switching element in each of the switching element groups 106 and 107, thereby causing an abnormal loss and eventually destroying the element. In the case of FIG. 15, the loss is considerably large in the ON state, and an abnormal increase in loss occurs in the state of the variable resistance at the time of switching. That is, the current flowing through the element is smaller in the case of FIG. 15 than when the duty is 100%, but the loss in the element becomes considerably large, and the element is eventually destroyed.
[0010]
Next, the relationship between the analog signal 110 and the PWM duty will be described based on FIG. When the triangular wave signal 120 is used as the PWM signal generation circuit 111, the analog signal and the PWM duty have a linear relationship as indicated by a straight line 125. When the target PWM duty is determined, the magnitude of the analog signal 110 is also uniquely determined by a simple expression represented by the straight line 125. If the steps are analog signal steps of the same size, the step size of the PWM duty is the same. Even when the amount of change in the duty of the PWM signal that determines the motor capacity is excessively large, such as when the motor is started or when the capacity is increased, a large current flows transiently in the switching element group (FET, etc.). In order to prevent this, a CR integration circuit 138 including a capacitor C and a resistor R for limiting the time change amount of the analog signal that is the output signal is built in the capability signal generation means 109.
[0011]
FIG. 17 shows the time change of the analog signal that has passed through the integration circuit 138. The most transient current flows through the switching element group (FET, etc.) most easily when the motor is started, and the analog signal 110a when the time change amount of the analog signal is determined by the constants C and R of the CR integration circuit 138 at the time of startup. It represents. Charging is started immediately after the start command, and when the lower limit value of the triangular wave signal 120 of the triangular wave generation circuit 112 is exceeded, a PWM signal is generated and energization of the motor winding 102 is started. As can be seen from the analog signal 110a, the normal charge / discharge circuit (CR circuit) has a feature that dV / dt (slope) is the largest at the charging start (start command) point, and the slope becomes smaller as the voltage increases.
[0012]
[Problems to be solved by the invention]
However, in the conventional method, when the PWM duty is below a certain lower limit value or above a certain upper limit value (excluding 100%), as can be seen from FIG. ) Does not completely turn on, and the loss in the switching element group (FET, etc.) increases rapidly. As a result, the efficiency is lowered, and eventually the parts are destroyed. As countermeasures for this, it is necessary to use a part having a sufficient margin or to attach a large heat sink to suppress the temperature rise. As a result, there has been a problem that a small and low-priced motor cannot be provided.
[0013]
  In addition, the conventional soft start method using a CR circuit that prevents transient current from flowing abnormally to the switching element group (FET, etc.) when the capacity is increased at the start of the motor or in response to an increase in load. Since dV / dt of the analog signal at the time of starting the PWM signal generation is fixedly set, it is not possible to cope with a case where the motor capacity is suddenly changed, and the controllability is deteriorated.MotaHad a problem.
[0014]
Accordingly, an object of the present invention is to provide a DC motor drive control device that reduces the period during which the switching element group is in a variable resistance state, is efficient, is inexpensive, and has high controllability.
[0015]
[Means for Solving the Problems]
  In order to solve this problem, the DC motor drive control device of the present invention is:A first switching element group comprising a plurality of phase motor driving coils for driving a DC motor, a switching element inserted between each of the motor driving coils and a positive pole of a DC power source for supplying power to the motor driving coil; A second switching element group consisting of switching elements inserted between the negative pole of the DC power supply and each motor drive coil, a plurality of magnetic pole position detecting elements for detecting the magnetic pole position of the rotor, and the magnetic poles An energization switching circuit that controls the first switching element group and the second switching element group based on an output signal of the position detection element and switches the motor driving coil to be fed from the DC power source, and the work of the load device of the DC motor Capability signal generating means for generating an analog signal having a voltage value corresponding to the result of the above, and a scan of the second switching element group. A PMW signal generation circuit that adjusts the amount of power supplied from the DC power source to the motor drive coil by outputting a PWM signal that is an ON / OFF signal of the switching element, and the PWM signal generation circuit outputs the PMW signal In this case, in the DC motor drive control device that sets the duty of the PMW signal to a value corresponding to the voltage value of the input analog signal, the voltage value of the analog signal of the capability signal generating means is monitored, and the voltage value is A voltage monitoring means for outputting a signal indicating that an upper limit value and a lower limit value respectively corresponding to upper and lower limits of the duty specification range of the PWM signal; and an output signal of the voltage monitoring means, and a voltage value of the analog signal Exceeds the upper limit value, the voltage value of the analog signal is converted to a first voltage and output to the PWM signal generation circuit, and the voltage of the analog signal is output. When the value falls below the lower limit value, the voltage value of the analog signal is converted into a second voltage and output to the PWM signal generation circuit, and the voltage value of the analog signal is equal to or lower than the upper limit value and higher than the lower limit value Comprises a signal conversion means for outputting the analog signal to the PWM signal generation circuit without converting the voltage value, and the first voltage is a voltage value with the duty of the PWM signal being 100%, and the second voltage Is a voltage value that makes the duty of the PWM signal 0%.
[0016]
As a result, the period during which the switching element group is in the variable resistance state can be reduced, and an efficient, inexpensive, and highly controllable DC motor drive control device can be obtained.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
  The invention described in claim 1 of the present invention isDriving a DC motorA multi-phase motor drive coil;The positive pole of the DC power supply that feeds the motor drive coilEachmotorBetween the drive coilEach consisting of inserted switching elementsA first switching element group;DCPower supply-PoleAnd each of the abovemotorBetween the drive coilEach consisting of inserted switching elementsBased on a second switching element group, a plurality of magnetic pole position detecting elements for detecting the magnetic pole position of the rotor, and an output signal of the magnetic pole position detecting elementThe motor drive for controlling the first switching element group and the second switching element group and supplying power from the DC power supplyAn energization switching circuit for switching coils;A capability signal generating means for generating an analog signal having a voltage value corresponding to a work result of the load device of the DC motor, and a PWM signal which is an ON / OFF signal of a switching element of the second switching element group, A PMW signal generation circuit that adjusts the amount of power supplied from the DC power source to the motor drive coil, and the PWM signal generation circuit outputs a voltage value of the analog signal to which the duty of the PMW signal is input when outputting the PMW signal. In the DC motor drive control device set to a value according to the above,Voltage monitoring means for monitoring the voltage value of the analog signal of the capability signal generating means and outputting a signal indicating that the voltage value has reached an upper limit value and a lower limit value respectively corresponding to the upper and lower limits of the duty specification range of the PWM signal; ,AboveIn response to the output signal from the voltage monitoring means,When the voltage value of the analog signal exceeds the upper limit value, the voltage value of the analog signal is converted into a first voltage and output to the PWM signal generation circuit, and the voltage value of the analog signal falls below the lower limit value When the voltage value of the analog signal is converted into a second voltage and output to the PWM signal generation circuit, the voltage value is not converted when the voltage value of the analog signal is not more than the upper limit value and not less than the lower limit value. The analog signal is output to the PWM signal generation circuitSignal conversion means,The first voltage is a voltage value that makes the duty of the PWM signal 100%, and the second voltage is a voltage value that makes the duty of the PWM signal 0%.Therefore, the voltage can be specified outside a predetermined duty specification range in the variable range (0 to 100%) of the duty of the PWM signal, and the temporal change amount (dV / dt) can be managed.
[0018]
  Also,It is prohibited to use the switching element group in a state where the variable resistance state is long, the abnormal heat generation of the switching element group is reduced, and an inexpensive and small motor driving device can be provided.
[0019]
  Claims of the invention2The invention described inDriving a DC motorA multi-phase motor drive coil;The positive pole of the DC power supply that feeds the motor drive coilEachmotorBetween the drive coilEach consisting of inserted switching elementsA first switching element group;DCPower supply-PoleAnd each of the abovemotorBetween the drive coilEach consisting of inserted switching elementsBased on a second switching element group, a plurality of magnetic pole position detecting elements for detecting the magnetic pole position of the rotor, and an output signal of the magnetic pole position detecting elementThe motor drive for controlling the first switching element group and the second switching element group and supplying power from the DC power supplyAn energization switching circuit for switching coils;A capability signal generating means for generating an analog signal having a voltage value corresponding to a work result of the load device of the DC motor, and a PWM signal which is an ON / OFF signal of a switching element of the second switching element group, A PMW signal generation circuit that adjusts the amount of power supplied from the DC power source to the motor drive coil, and the PWM signal generation circuit outputs a voltage value of the analog signal to which the duty of the PMW signal is input when outputting the PMW signal. In the DC motor drive control device set to a value according to the above,Voltage monitoring means for monitoring the voltage value of the analog signal of the capability signal generating means and outputting a signal indicating that the voltage value has reached an upper limit value and a lower limit value respectively corresponding to the upper and lower limits of the duty specification range of the PWM signal; ,AboveIn response to the output signal from the voltage monitoring means,When the voltage value of the analog signal exceeds the upper limit value, the duty of the PMW signal output from the PWM signal generation circuit is converted to 100%, and when the voltage value of the analog signal falls below the lower limit value, The duty of the PMW signal output from the PWM signal generation circuit is converted to 0%. When the voltage value of the analog signal is equal to or lower than the upper limit value and equal to or higher than the lower limit value, the duty of the PMW signal output to the PWM signal generation circuit is changed. Provided with signal conversion means that does not convertTherefore, it is possible to designate a duty outside the predetermined duty designation range of the PWM signal, to manage the amount of time change of the PWM signal, and to provide a motor drive device with good responsiveness. Can be provided.
[0020]
  Claims of the invention3The invention described inIn claim 1 or 2,The induced voltage of one phase is V^*, Power supply voltage for power supply is V, voltage applied to winding is V₁, D is the allowable initial duty when starting the motor_min(%), Where β is a coefficient (β = 1.35 to 1.55), V₁= V-β × V^*And the maximum change amount D of the duty of the PWM signal_max(%) Is D_max= D_min+ D_min× (β × V^*/ V₁), And the upper limit of the duty specification range of the PWM signal is D_max(%), Lower limit is D_minSince the DC motor drive control device is characterized in that it is set to (%), the current flowing through the switching element group at the time of startup is limited to prevent the destruction of parts, and the responsive DC motor drive device Can provide.
[0021]
(Embodiment 1)
The motor drive control apparatus according to Embodiment 1 of the present invention will be described below. FIG. 1 is a configuration diagram of a motor drive control apparatus according to Embodiment 1 of the present invention. The description of the same reference numerals as those of the conventional technology is omitted. Reference numeral 101 denotes a DC power source, 102 denotes a motor winding (motor driving coil of the present invention) supplied with electricity from the DC power source 101, 103 denotes a magnet rotor, and 104 denotes a magnetic pole position detecting element. Reference numeral 105 denotes an energization switching circuit, 106 denotes a first switching element group, and 107 denotes a second switching element group. 108 is a load detecting means, 109 is a capability signal generating means, and 110 is an analog signal serving as a command value for changing the capability of the drive motor. Reference numeral 111 denotes a PWM signal generation circuit that generates a PWM signal in which a power supply command to the motor winding 102 is proportional to the pulse width. Reference numeral 112 denotes a triangular wave that generates a triangular wave signal having a specific period (several kHz) in the PWM signal generation circuit. A generation circuit, 113 is a comparison circuit, 120 is a triangular wave signal, and 138 is a CR integration circuit.
[0022]
Reference numeral 150 denotes voltage monitoring means for monitoring the magnitude of the voltage, 151 denotes its voltage monitoring detection signal, and 152 denotes signal conversion means for receiving the voltage monitoring detection signal 151.
[0023]
The detection signal of the load detection means 108 is received, the work result of the current load (pressure or flow rate if the load is a pump) is detected, and the capability signal so that the work result (pressure or flow rate) of the target load is obtained. An analog signal 110 for changing the capability of the drive motor is output from the generation means 109.
[0024]
The analog signal 110 is input to the voltage monitoring unit 150 that monitors the magnitude of the voltage, and the voltage monitoring unit 150 determines whether the voltage magnitude is equal to or lower than the set lower limit value or higher than the set upper limit value. The determined voltage monitoring detection signal 151 is input to the signal conversion unit 152. Further, the analog signal 110 is directly input from the capability signal generator 109 to the signal converter 152. The signal converted by the signal conversion means 152 is converted into the converted analog signal 110.^*Is input to the PWM signal generation circuit 111.
[0025]
Next, the voltage monitoring unit 150 according to the first embodiment of the present invention will be described with reference to FIGS. 2 and 3 show different forms of the voltage monitoring means 150, respectively. FIG. 2 is a configuration diagram of a voltage monitoring apparatus using an FET according to the first embodiment of the present invention. In FIG. 2, 150a is an inverter that inverts the output signal, 153 is a set voltage that becomes a lower limit value or an upper limit value of the analog signal 110, 154 is an FET that is a switching means, and 155 and 156 are resistors. The voltage monitoring means 150 in the form shown in FIG. 2 uses the FET 154 for the output analog signal 110 generated by the capability signal generation means 109 and turns it on / off according to the magnitude of the analog signal 110. The FET 154 is turned on / off according to four factors: the set voltage 153 of the analog signal 110, the resistance value of the resistors 155 and 156, the voltage between the gate and the source where the FET 154 is turned on, and the magnitude of the power supply + PWR. In the present embodiment, when the analog signal 110 is larger than the set voltage 153, the signal is inverted by the inverter 150a so as to output Low, and the voltage monitoring detection signal 151 is output.
[0026]
Next, FIG. 3 is a configuration diagram of a voltage monitoring apparatus using the comparator according to Embodiment 1 of the present invention. In FIG. 3, reference numeral 157 denotes a comparator. In the present embodiment, the analog signal 110 that is the output of the capability signal generating means 109 is connected to the negative pole of the comparator 157, and the signal from the voltage dividing resistor that sets a voltage value equivalent to the set voltage 153 is connected to the positive pole. Thus, when the analog signal 110 becomes larger than the set voltage 153 that is the lower limit value or the upper limit value, the voltage monitoring detection signal 151 of the comparator 157 becomes Low and is output.
[0027]
Next, the signal conversion means in Embodiment 1 of this invention is demonstrated using FIG. FIG. 4 is an explanatory diagram of signal conversion means for converting the output of the capability signal generation means of the DC motor drive control apparatus according to Embodiment 1 of the present invention.
[0028]
4, 151a and 151b are allowable voltage monitoring detection signals of the voltage monitoring means 150, 153a is a lower limit value of the analog signal 110 in the duty designation range, 153b is an upper limit value of the analog signal 110 in the duty designation range, and 158 is a 1 × buffer. It is an amplifier. The output of the capability signal generation means 109 is turned on / off at a lower limit value 153a and an upper limit value 153b, and the allowable voltage monitoring detection signals 151a and 151b are output from the voltage monitoring means 150 to two. In the signal converting means 152, the allowable voltage monitoring detection signal 151a corresponding to the lower limit value 153a is connected to the base of the N-type transistor, and the allowable voltage monitoring detection signal 151b corresponding to the upper limit value 153b is connected to the base of the P-type transistor. Is done. The N-type and P-type transistors are connected by a totem pole and output as one output signal. This output signal is connected to a signal obtained by passing the analog signal 110 from the capability signal generating means 109 through the 1 × buffer amplifier 158, and the superimposed signal is output from the signal converting means 152 (the converted analog signal 110).^*) Is output. The converted analog signal 110^*As shown in FIG. 4, the value is the same as that of the analog signal 110 from the lower limit value 153a to the upper limit value 153b. However, when the lower limit setting value 153a or less, the voltage (the value at which the duty of the PWM signal becomes 0%) is low. When the upper limit setting value 153b is exceeded, the voltage becomes high (a value at which the duty of the PWM signal becomes 100%) (the first voltage of the present invention).
[0029]
Next, a relation curve 126 between the analog signal 110 before conversion and the PWM duty in the first embodiment of the present invention will be described with reference to FIG. FIG. 7 is an explanatory diagram of the relationship between the analog signal before conversion and the PWM duty in the first embodiment of the present invention. Since the signal conversion means 152 is provided at a position for receiving the analog signal 110 of the capability signal generation means 109, the converted analog signal 110 input to the PWM signal generation circuit 111.^*The voltage value changes in two steps at the lower limit value and the upper limit value. In FIG. 7, since the PWM duty also changes stepwise at these two locations, the analog signal 110 before conversion shows that the duty is 0% when the value is lower than the lower limit, and the duty is 100% when the upper limit is exceeded. ing. In the first embodiment, the duty designation range is determined from the aspect of preventing heat generation of the switching element group. However, the duty designation range according to the purpose can be designated from other aspects.
[0030]
(Embodiment 2)
The motor drive control apparatus according to the second embodiment of the present invention will be described below. The motor drive control apparatus according to the second embodiment is characterized in that the signal conversion means is arranged at a position for receiving the output of the PWM signal generation circuit. Since the same reference numerals as those of the motor drive control apparatus of the first embodiment are the same, the detailed description will be omitted with reference to FIGS.
[0031]
FIG. 5 is a block diagram of a motor drive control apparatus according to Embodiment 2 of the present invention, and FIG. 6 is an explanatory diagram of signal conversion means of the motor drive control apparatus according to Embodiment 2 of the present invention. 5 and 6, 101 is a DC power source, 102 is a motor winding, 103 is a magnet rotor, 104 is a magnetic pole position detecting element, 105 is an energization switching circuit, 106 is a first switching element group, and 107 is a second switching element group. It is. 108 is a load detecting means, 109 is a capability signal generating means, and 110 is an analog signal. 111 is a PWM signal generating circuit for generating a PWM signal, 112 is a triangular wave generating circuit, 113 is a comparison circuit, 120 is a triangular wave signal, and 138 is a CR integrating circuit. Reference numeral 150 denotes voltage monitoring means, 151 denotes a voltage monitoring detection signal, and 152 denotes signal conversion means.
[0032]
The motor drive control apparatus according to the second embodiment also receives the detection signal from the load detection means 108, detects the current load work result (pressure or flow rate if the load is a pump), and the target load work result. An analog signal 110 for changing the capacity of the drive motor is output from the capacity signal generating means 109 so that the pressure or flow rate is obtained.
[0033]
The analog signal 110 is input to the voltage monitoring unit 150 that monitors the magnitude of the voltage, and the voltage monitoring unit 150 determines whether the voltage magnitude is equal to or lower than the set lower limit value or higher than the set upper limit value. The determined voltage monitoring detection signal 151 is input to the signal conversion unit 152. Further, the comparison circuit output signal 121 of the PWM signal generation circuit 111 is input to the signal conversion means 152. The comparison circuit output signal 121 is obtained by comparing the analog signal 110 output from the capability signal generation means 109 with the triangular wave signal 120 output from the triangular wave generation circuit 112 by the comparison circuit 113. The signal converted by the signal conversion means 152 is the comparison circuit output signal 121.^*Is input to the energization switching circuit 105.
[0034]
Next, the voltage monitoring unit 150 according to the second embodiment of the present invention will be described with reference to FIGS. FIG. 2 shows a voltage monitoring apparatus using FETs in the second embodiment. In FIG. 2, 150a is an inverter, 153 is a set voltage, 154 is an FET, and 155 and 156 are resistors. When the analog signal 110 is larger than the set voltage 153, the signal is inverted by the inverter 150a so as to become Low, and the voltage monitor detection signal 151 is output.
[0035]
Next, FIG. 3 shows a voltage monitoring apparatus using a comparator in the second embodiment. In FIG. 3, reference numeral 157 denotes a comparator. When the analog signal 110 becomes larger than the lower limit value or the upper limit value 153, the voltage monitoring detection signal 151 of the comparator 157 becomes Low and is output.
[0036]
Next, the signal conversion means in Embodiment 2 of this invention is demonstrated using FIG. In FIG. 6, the output signal of the voltage monitoring means 150 is the same as that in the first embodiment, and the description thereof is omitted. In FIG. 6, reference numerals 159 and 160 denote photocouplers. The analog signal 110 that is the output of the capability signal generation means 109 is input to the PWM signal generation circuit 111, the magnitude of the duty is determined according to the magnitude of the analog signal 110, and the PWM signal generation circuit 111 is used as the comparison circuit output signal 121. Is output from.
[0037]
On the other hand, the signal converting means 152 receives the allowable voltage monitoring detection signal 151a indicating the lower limit value and the allowable voltage monitoring detection signal 151b indicating the upper limit value from the voltage monitoring means 150, passes through the respective buffers, and the output signals thereof are photocouplers. 159 and 160 are connected to the primary side. Thereafter, the secondary sides of the photocouplers 159 and 160 are connected by a totem pole as shown in FIG. 6, and the comparison circuit output signal 121 is also connected to become an output signal of the signal conversion means 152, and the converted comparison circuit output signal 121 is converted.^*Is output as The converted comparison circuit output signal 121^*Can be selected continuously up to the lower limit duty and the upper limit duty, but the duty is 0% below the lower limit, and 100% above the upper limit.
[0038]
Next, the relationship curve 126 between the analog signal 110 before conversion and the PWM duty in Embodiment 2 of the present invention will be described. Since the signal conversion means 152 receives the comparison circuit output signal 121 of the PWM signal generation circuit 111 and also receives the voltage monitoring detection signal 151, the comparison circuit output signal 121 monitors the voltage at two places below the lower limit and above the upper limit. A voltage that goes High and Low is applied using the detection signal 151 as a trigger, and the duty changes stepwise. When the analog signal 110 before conversion is equal to or lower than the lower limit value, the duty is 0%, and when the analog signal 110 is equal to or higher than the upper limit value, the duty is 100%.
[0039]
(Embodiment 3)
Next, a motor drive control apparatus for controlling the amount of change in PWM duty in Embodiment 3 of the present invention will be described with reference to FIGS. FIG. 8 is an electric circuit diagram of the three-phase motor according to the third embodiment of the present invention, and FIG. 9 is a composite voltage waveform diagram for two phases of the induced voltage of the three-phase brushless motor according to the third embodiment of the present invention. 10 is a state diagram of a change in PWM duty in the third embodiment of the present invention.
[0040]
First, in FIG. 8, 140U, 140V, and 140W are U-phase, V-phase, and W-phase induced voltages, 141U, 141V, and 141W are U-phase, V-phase, and W-phase inductance components, and 142U, 142V, and 142W are respectively The U-phase, V-phase, and W-phase resistance components, 143U, 143V, and 143W are U-phase, V-phase, and W-phase terminals, respectively. Inductive voltages 140U, 140V, and 140W are generated by the rotation of the magnet rotor 103 in the windings of each phase of the three-phase brushless motor, and each winding has an inductance component 141U, 141V, 141W and a resistance component 142U on the electric circuit. It shows having 142V and 142W. In particular, in the 120-degree energization method, which is a general driving method of a three-phase DC motor, the first voltage is applied so that the power supply voltage is applied to the large two-phase terminals 143U, 143V, and 143W among the induced voltages 140U, 140V, and 140W in each winding. One element in the switching element group 106 and one element in the second switching element group 107 are turned on.
[0041]
Next, in FIG. 9, 144 is a 120-degree energization method and is a waveform of one phase switching interval (a period in which the energized two phases have a larger induced voltage than the other one), 145 is a power supply voltage, and 146 is immediately after phase switching Is the voltage applied to the winding. That is, the enlarged view of FIG. 9 shows a section in which the energized two-phase 140U, 140V has a larger induced voltage than the other one-phase 140W, and the magnitude of the induced voltage of one phase is V^*Then, the magnitude of the induced voltage for two phases is 1.5 V as shown in the waveform 144.^*To 1.7V^*Fluctuate between. When the phase switching timing is slightly advanced, the voltage 146 applied to the winding immediately after the phase switching increases by advancing the angle. That is, the voltage 146 applied to this winding is indicated by the hatched portion in FIG.₁It is. Further, since the current sufficiently flows when the resultant voltage of the two-phase induced voltage is the largest by advancing, there is a feature that the maximum output of the motor can be obtained.
[0042]
By the way, induced voltage V^*Is
V^*= Α ・ N
Here, α (V / rpm) is a coefficient (an induced voltage constant determined for each motor), and N (rpm) is a rotation speed. Therefore, the voltage 146 applied to the winding is V.^*Becomes smaller at this time. This minimizes the PWM duty (D_min(%)) Can be set.
[0043]
Next, in FIG. 10, 110a is a time change curve of PWM duty when the change amount of the analog signal is limited by the CR integration circuit, and 147 is an allowable maximum change amount D of the duty._maxIt is a time change curve of PWM duty when (%) is calculated. When the capability signal generation means 109 and the PWM signal generation circuit 111 are configured by a microcomputer (central processing unit), a PWM signal is directly output from the microcomputer. In this case, a control program is loaded from a memory (not shown) to the microcomputer, and the capability signal generating means 109 is configured as a function realizing means. Similarly, the PWM signal generation circuit 111 is also loaded with a control program from the memory and is configured as a function realization unit on the microcomputer. If it is set by input from a microcomputer, the amount of change in duty of the PWM signal can be controlled freely.
[0044]
By the way, in Embodiment 3, the allowable maximum change amount D of the duty of the PWM signal is expressed by the following equation._maxSet (%).
[0045]
D_max= D_min+ D_min× (β × V^*/ V₁)
β is a coefficient (depending on the advance angle of phase switching, β = 1.35 to 1.55), D_min(%) Is the allowable initial duty when the motor starts. In the 120-degree conduction method, V₁= V-β × V^*PMW signal duty at startup D_minAnd D_maxD during_max/ D_min= V / (V−β × V^*) Holds, the above equation is derived. Induced voltage V^*Is proportional to the rotational speed N as described above, the rotational speed signal is calculated from the detection signal of the magnetic pole position detecting element 104 to calculate the rotational speed, and the product of the result and the coefficient α is used to generate the induced voltage. V^*You can ask for.
[0046]
The drive control apparatus according to the third embodiment has the allowable maximum change amount D._max(%) Is calculated, and the upper limit value of the PWM signal is set to D in the drive control devices of the first and second embodiments._max(%), Lower limit is D_minIt is set as (%). The time change curve 147 of the PWM duty when activated by this drive control device shows a very fast rise as shown in FIG. That is, the maximum amount of change D when the duty increases_maxBy limiting (%), transient current can be suppressed and stress on the switching element can be reduced. The time change curve 110a in which the change amount of the analog signal is limited by the conventional CR integration circuit is a slow response, and the driving device according to the third embodiment of the present invention is clearly more control responsive than the conventional CR integration circuit. It turns out that is good.
[0047]
【The invention's effect】
As described above, according to the motor drive control device of the present invention, it is possible to reduce the period during which the switching element group is in a variable resistance state, and to provide an efficient, inexpensive, and small motor drive device. The maximum amount of change D when the duty increases_maxBy limiting (%), it is possible to provide a motor drive device that suppresses transiently flowing current, reduces stress on the switching element, and maximizes control responsiveness within the range.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a motor drive control device according to a first embodiment of the present invention.
FIG. 2 is a configuration diagram of a voltage monitoring device using an FET according to the first embodiment of the present invention.
FIG. 3 is a configuration diagram of a voltage monitoring apparatus using a comparator according to the first embodiment of the present invention.
FIG. 4 is an explanatory diagram of signal conversion means for converting the output of the capability signal generation means of the DC motor drive control apparatus according to Embodiment 1 of the present invention;
FIG. 5 is a configuration diagram of a motor drive control device according to a second embodiment of the present invention.
FIG. 6 is an explanatory diagram of signal conversion means of the motor drive control device according to the second embodiment of the present invention.
7 is an explanatory diagram of a relationship between an analog signal before conversion and PWM duty in Embodiment 1 of the present invention; FIG.
FIG. 8 is an electric circuit diagram of a three-phase motor according to Embodiment 3 of the present invention.
FIG. 9 is a composite voltage waveform diagram of two phases of the induced voltage of the three-phase brushless motor according to the third embodiment of the present invention.
FIG. 10 is a state diagram of a change in PWM duty in Embodiment 3 of the present invention.
FIG. 11 is a configuration diagram of a conventional DC motor driving apparatus using a conventional PWM signal generation circuit.
FIG. 12: ON / OFF characteristic diagram of switching element
FIG. 13 is a first signal waveform diagram in a conventional PWM signal generation circuit;
FIG. 14 is a second signal waveform diagram in the conventional PWM signal generation circuit;
FIG. 15 is a third signal waveform diagram in the conventional PWM signal generation circuit;
FIG. 16 is an explanatory diagram of the relationship between the voltage of an analog signal generated from a conventional capability signal generating means and the duty of a PWM signal.
FIG. 17 is a waveform diagram showing a time change of an analog signal which is an output signal from an integrating circuit in the capability signal generating means.
[Explanation of symbols]
101 DC power supply
102 Motor winding
103 Magnet rotor
104 Magnetic pole position detection element
105 Energization switching circuit
106 First switching element group
107 Second switching element group
108 Load detection means
109 Capability signal generating means
110 Analog signal
110^*  Command analog voltage after signal conversion
110a Time variation curve of PWM signal duty
111 PWM signal generation circuit
112 Triangular wave generator
113 Comparison circuit
120 triangular wave signal
121 Comparison circuit output signal
121^*  Comparison circuit output signal after signal conversion
122 PWM signal
123 GS voltage value at the boundary between switching element OFF and variable resistance state
124 GS voltage value at the boundary between switching element ON and variable resistance state
125 straight line
126 Relationship curve of PWM duty
138 CR integration circuit
140U, 140V, 140W induced voltage
141U, 141V, 141W U, V, W phase inductance components
142U, 142V, 142W U, V, W phase resistance components
143U, 143V, 143W U, V, W phase terminals
144 Combined waveform of two-phase induced voltage
145 Power supply voltage
146 Voltage applied to winding
147 Duty time curve
150 Voltage monitoring means
150a inverter
151 Voltage monitoring detection signal
151a, 151b Permissible voltage monitoring detection signal
152 Signal conversion means
153 Setting voltage
153a Lower limit
153b Upper limit
154 FET
155 resistor
156 resistor
157 Comparator
158 1x buffer amplifier
159 Photocoupler
160 Photocoupler

Claims

A motor driving coil of a plurality of phases to drive the DC motor, and a first switching element group composed of switching elements inserted respectively between the positive pole of the DC power source for supplying power to the motor driving coil and the respective motor driving coils, A second switching element group consisting of switching elements inserted between the negative pole of the DC power supply and each motor drive coil, a plurality of magnetic pole position detecting elements for detecting the magnetic pole position of the rotor, and the magnetic poles An energization switching circuit that controls the first switching element group and the second switching element group based on an output signal of the position detection element and switches the motor driving coil to be fed from the DC power source, and the work of the load device of the DC motor Capability signal generating means for generating an analog signal having a voltage value corresponding to the result of the above, and a scan of the second switching element group. A PMW signal generation circuit that adjusts the amount of power supplied from the DC power source to the motor drive coil by outputting a PWM signal that is an ON / OFF signal of the switching element, and the PWM signal generation circuit outputs the PMW signal In the DC motor drive control device for setting the duty of the PMW signal to a value corresponding to the voltage value of the input analog signal,
Wherein monitoring the voltage value of the analog signal capability signal generating means, the voltage monitoring means for said voltage value to output a signal indicating that it's upper and lower limit values corresponding respectively to the upper and lower limits of the duty specified range of the PWM signal When,
In response to the output signal of the voltage monitoring means, when the voltage value of the analog signal exceeds the upper limit value, the voltage value of the analog signal is converted into a first voltage and output to the PWM signal generating circuit, and the analog signal is output. When the voltage value of the signal falls below the lower limit value, the voltage value of the analog signal is converted to a second voltage and output to the PWM signal generation circuit, and the voltage value of the analog signal is equal to or lower than the upper limit value and higher than the lower limit value A signal converting means for outputting the analog signal to the PWM signal generating circuit without converting the voltage value .
The first voltage is a voltage value in which the duty of the PWM signal is 100%,
2. The DC motor drive control device according to claim 1, wherein the second voltage is a voltage value that sets the duty of the PWM signal to 0% .

A first switching element group comprising a plurality of phase motor driving coils for driving a DC motor, a switching element inserted between each of the motor driving coils and a positive pole of a DC power source for supplying power to the motor driving coil; A second switching element group consisting of switching elements inserted between the negative pole of the DC power supply and each motor drive coil, a plurality of magnetic pole position detecting elements for detecting the magnetic pole position of the rotor, and the magnetic poles An energization switching circuit that controls the first switching element group and the second switching element group based on an output signal of the position detection element and switches the motor driving coil to be fed from the DC power source, and the work of the load device of the DC motor Capability signal generating means for generating an analog signal having a voltage value corresponding to the result of the above, and a scan of the second switching element group. A PMW signal generation circuit that adjusts the amount of power supplied from the DC power source to the motor drive coil by outputting a PWM signal that is an ON / OFF signal of the switching element, and the PWM signal generation circuit outputs the PMW signal In the DC motor drive control device for setting the duty of the PMW signal to a value corresponding to the voltage value of the input analog signal,
Voltage monitoring means for monitoring the voltage value of the analog signal of the capability signal generating means and outputting a signal indicating that the voltage value has reached an upper limit value and a lower limit value respectively corresponding to the upper and lower limits of the duty specification range of the PWM signal When,
In response to the output signal of the voltage monitoring means, when the voltage value of the analog signal exceeds the upper limit, the duty of the PMW signal output from the PWM signal generation circuit is converted to 100%, and the voltage of the analog signal When the value falls below the lower limit value, the duty of the PMW signal output from the PWM signal generation circuit is converted to 0%, and when the voltage value of the analog signal is lower than the upper limit value and higher than the lower limit value, the PWM signal is output. D C motor drive control device you characterized in that a signal converting means does not convert the duty of the PMW signals to be output to the signal generating circuit.

The induced voltage for one phase is V ^* , the power supply voltage for power supply is V, the voltage applied to the winding is V ₁ , the allowable initial duty at the start of the motor is D _min ( % ) , and β is a coefficient (β = 1.35) ~ 1.55)
V ₁ = V−β × V ^* ,
The maximum amount of change D _max (%) of the duty of the PWM signal is
D _max = D _min + D _min × (β × V ^* / V ₁ ),
The DC motor drive control device according to claim 1 or 2, wherein the upper limit of the duty specification range of the PWM signal is set to D _max (%) and the lower limit is set to D _min ( % ) .