JP4140244B2 - Inverter control method and power saving device using the control method - Google Patents

Description

【００４３】
【式２】

【００４４】
なお、Ｖｄｃはコンデンサ９ｃの両端電圧のＤＣリンク電圧で、ｉ１はリアクトル７ａ、７ｂに流れる電流、ｉ２はリアクトル７ｃ、７ｄに流れる電流である。ここで、個別の変調率で制御する変調率制御手段の制御フローについて、スイッチングパターンを交流電源Ｖｉｎと双方向インバータ１の出力電圧Ｖｏｕｔが同位相の場合と逆位相の場合の２つに分けて説明する。
【００４５】
同位相の場合のタイミングチャートを図２に示す。図２に示すように、各アームの変調率とキャリア波との比較を定義し、交流電源Ｖｉｎと双方向インバータ１の出力電圧Ｖｏｕｔのそれぞれが正の半周期、交流電源Ｖｉｎが双方向インバータ１の出力電圧Ｖｏｕｔより大きい時、モードは４パターンある。スイッチング素子３ａがＯＮ、３ｂがＯＦＦ、３ｃがＯＦＦ、３ｄがＯＮ、３ｅがＯＦＦ、３ｆがＯＮのパターンＡと、３ａがＯＮ、３ｂがＯＦＦ、３ｃがＯＦＦ、３ｄがＯＮ、３ｅがＯＮ、３ｆがＯＦＦのパターンＢと、３ａがＯＮ、３ｂがＯＦＦ、３ｃがＯＮ、３ｄがＯＦＦ、３ｅがＯＮ、３ｆがＯＦＦのパターンＣと、３ａがＯＦＦ、３ｂがＯＮ、３ｃがＯＦＦ、３ｄがＯＮ、３ｅがＯＦＦ、３ｆがＯＮのパターンＤである。また、交流電源Ｖｉｎと双方向インバータ１の出力電圧Ｖｏｕｔのそれぞれが負の半周期の時、同様にモードは４パターンある。スイッチング素子３ａがＯＦＦ、３ｂがＯＮ、３ｃがＯＮ、３ｄがＯＦＦ、３ｅがＯＮ、３ｆがＯＦＦのパターンＥと、３ａがＯＮ、３ｂがＯＦＦ、３ｃがＯＮ、３ｄがＯＦＦ、３ｅがＯＮ、３ｆがＯＦＦのパターンＦと、３ａがＯＦＦ、３ｂがＯＮ、３ｃがＯＮ、３ｄがＯＦＦ、３ｅがＯＦＦ、３ｆがＯＮのパターンＧと、３ａがＯＦＦ、３ｂがＯＮ、３ｃがＯＦＦ、３ｄがＯＮ、３ｅがＯＦＦ、３ｆがＯＮのパターンＨである。
【００４６】
逆位相の場合のタイミングチャートを図３に示す。図３に示すように、交流電源Ｖｉｎが正の半周期時で、かつ双方向インバータ１の出力電圧Ｖｏｕｔが負の半周期の時、モードは４パターンある。スイッチング素子３ａがＯＮ、３ｂがＯＦＦ、３ｃがＯＦＦ、３ｄがＯＮ、３ｅがＯＦＦ、３ｆがＯＮのパターンＡと、３ａがＯＮ、３ｂがＯＦＦ、３ｃがＯＮ、３ｄがＯＦＦ、３ｅがＯＦＦ、３ｆがＯＮのパターンＢと、３ａがＯＮ、３ｂがＯＦＦ、３ｃがＯＮ、３ｄがＯＦＦ、３ｅがＯＮ、３ｆがＯＦＦのパターンＣと、３ａがＯＦＦ、３ｂがＯＮ、３ｃがＯＦＦ、３ｄがＯＮ、３ｅがＯＦＦ、３ｆがＯＮのパターンＤである。また、交流電源Ｖｉｎが負の半周期で、かつ双方向インバータ１の出力電圧Ｖｏｕｔが正の半周期の時、同様にモードは４パターンある。すなわち、スイッチング素子３ａがＯＮ、３ｂがＯＦＦ、３ｃがＯＮ、３ｄがＯＦＦ、３ｅがＯＮ、３ｆがＯＦＦのパターンＥと、３ａがＯＦＦ、３ｂがＯＮ、３ｃがＯＮ、３ｄがＯＦＦ、３ｅがＯＮ、３ｆがＯＦＦのパターンＦと、３ａがＯＦＦ、３ｂがＯＮ、３ｃがＯＦＦ、３ｄがＯＮ、３ｅがＯＮ、３ｆがＯＦＦのパターンＧと、３ａがＯＦＦ、３ｂがＯＮ、３ｃがＯＦＦ、３ｄがＯＮ、３ｅがＯＦＦ、３ｆがＯＮのパターンＨである。
【００４７】
同位相の場合、図１中の各部の電圧、すなわち、スイッチング素子３ｂの両端電圧Ｖａ、スイッチング素子３ｄの両端電圧Ｖｂ、スイッチング素子３ｆの両端電圧ＶｃにはＶａ＞Ｖｂ、Ｖｃ＞ＶｂあるいはＶａ＜Ｖｂ、Ｖｃ＜Ｖｂの２つの組合せがある。
【００４８】
Ｖａ＞Ｖｂ、Ｖｃ＞Ｖｂの場合、交流電源電圧が正の期間にスイッチング素子３ａ、３ｄがＯＮの期間にスイッチング素子３ｅをＯＮにすることにより、双方向インバータ１の出力電圧は正の電圧すなわちＶｃ＞Ｖｂを印加することができる。従ってスイッチング素子３ａ、３ｄがＯＮの期間の間にスイッチング素子３ｅをＯＮさせることで交流電源の正の期間と同位相の双方向インバータ１の出力、すなわちＶａ＞Ｖｂの時にＶｃ＞Ｖｂの双方向インバータ１の出力が可能となる。Ｖａ＜Ｖｂ、Ｖｃ＜Ｖｂの場合は、スイッチング素子３ｂ、３ｃがＯＮの期間にスイッチング素子３ｆをＯＮすることで交流電源の負の期間と同位相の双方向インバータ１の出力、すなわちＶａ＜Ｖｂの時にＶｃ＜Ｖｂの双方向インバータ１の出力が可能となる。
【００４９】
図４に示すように、スイッチング素子３ａ〜３ｆのスイッチングパターンを各Ｔ１〜Ｔ６し、キャリア周期をＴ、パターンＡ〜Ｄまでの各時間をＴａ〜Ｔｄとした場合、同位相時の各モードにおける回路方程式は式３となる。
【００５０】
【式３】

【００５１】
式３の各式の両辺に各ＴａからＴｄ倍し、総和を計算、整理すると式１となる。
【００５２】
次に逆位相の場合、図１中の各部の電圧Ｖａ、Ｖｂ、ＶｃにはＶａ＞Ｖｂ、Ｖｃ＜ＶｂあるいはＶａ＜Ｖｂ、Ｖｃ＞Ｖｂの２つの組合せがある。
【００５３】
Ｖａ＞Ｖｂ、Ｖｃ＜Ｖｂの場合、スイッチング素子３ｂ、３ｃがＯＮの期間にスイッチング素子３ｆをＯＮにすることにより、交流電源の正の期間に双方向インバータ１の出力電圧は負の電圧すなわちＶｃ＜Ｖｂを印加することができる。従ってスイッチング素子３ｂ、３ｃがＯＮの期間の間にスイッチング素子３ｆをＯＮさせることで、交流電源に対して逆位相の双方向インバータ１の出力、すなわちＶａ＞Ｖｂの時にＶｃ＜Ｖｂの双方向インバータ１の出力が可能となる。Ｖａ＜Ｖｂ、Ｖｃ＞Ｖｂの場合は、スイッチング素子３ａ、３ｄがＯＮの期間にスイッチング素子３ｅをＯＮすることで、交流電源に対して逆位相の双方向インバータ１の出力、すなわちＶａ＜Ｖｂの時にＶｃ＞Ｖｂの双方向インバータ１の出力が可能となる。逆位相時も同位相時と同様に式１を導くことができる。
【００５４】
以上のように同位相、逆位相共にスイッチング素子３ａ〜３ｆをＯＮ／ＯＦＦ比で制御することにより双方向インバータ１の出力電圧制御が可能となる。
【００５５】
スイッチング素子３ａ〜３ｆのデューティＤ１、Ｄ２の決定方法については、式１、式２からデューティＤ１、Ｄ２により双方向インバータ１の入出力電圧は決定することができるため、デューティＤ１、Ｄ３の計算を行うと、式４のようになる。
【００５６】
【式４】

【００５７】
このようにキャリア信号との比較により、デューティＤ１〜Ｄ３を決定し、スイッチング素子３ａ〜３ｆを制御することとなる。
【００５８】
以上のように本実施例によれば、交流電源に対してインバータは同位相、逆位相共に出力することができる。
【００５９】
なお、本実施例においては、各アームの変調率とキャリア波の比較から各スイッチング素子のデューティを出力する際に正論理としたが、負論理であっても効果に差異はない。
【００６０】
（実施例２）
以下、本発明の第２実施例（実施例２〜４に対応）について、図５及び図６を参照しながら説明する。
【００６１】
なお、第１実施例と同一部分には同一番号を付し、その詳細な説明は省略する。
【００６２】
図１の回路において、スイッチング素子３ａとスイッチング素子３ｄ、スイッチング素子３ｂとスイッチング素子３ｃの各組合せが互いに符号を反転させた変調率でＯＮしている状態において、双方向インバータ１の出力電圧目標値が双方向インバータ１の出力電圧限界を超えた場合について説明する。
【００６３】
上記のスイッチング素子３ａとスイッチング素子３ｄの組合せが変調率ｍ＿ｃ、スイッチング素子３ｂとスイッチング素子３ｃの組合せが変調率−ｍ＿ｃすなわちスイッチング素子３ａ、３ｄの組み合わせの符号を反転した変調率で、かつ異なるタイミングでＯＮしている状態の場合、交流電源電圧Ｖｉｎは式５のように、負荷８側の電圧Ｖｏｕｔは式６のように計算することができる。
【００６４】
【式５】

【００６５】
【式６】

【００６６】
ここで、個別の変調率で制御する変調率制御手段の制御フローについて、スイッチングパターンを交流電源Ｖｉｎと双方向インバータ１の出力電圧Ｖｏｕｔが同位相の場合と逆位相の場合の２つに分けて説明する。
【００６７】
同位相の場合のタイミングチャートを図５に示す。図５に示すように、交流電源Ｖｉｎと双方向インバータ１の出力電圧Ｖｏｕｔのそれぞれが正の半周期の時で、かつＶｏｕｔ＜Ｖｉｎの時、モードは次の４パターンある。すなわち、スイッチング素子３ａがＯＮ、３ｂがＯＦＦ、３ｃがＯＦＦ、３ｄがＯＮ、３ｅがＯＦＦ、３ｆがＯＮのパターンＡと、３ａがＯＮ、３ｂがＯＦＦ、３ｃがＯＦＦ、３ｄがＯＮ、３ｅがＯＮ、３ｆがＯＦＦのパターンＢと、３ａがＯＮ、３ｂがＯＦＦ、３ｃがＯＮ、３ｄがＯＦＦ、３ｅがＯＮ、３ｆがＯＦＦのパターンＣと、３ａがＯＦＦ、３ｂがＯＮ、３ｃがＯＦＦ、３ｄがＯＮ、３ｅがＯＦＦ、３ｆがＯＮのパターンＤである。また、交流電源Ｖｉｎと双方向インバータ１の出力電圧Ｖｏｕｔのそれぞれが負の半周期の時、同様にモードは４パターンある。スイッチング素子３ａがＯＮ、３ｂがＯＦＦ、３ｃがＯＮ、３ｄがＯＦＦ、３ｅがＯＮ、３ｆがＯＦＦのパターンＥと、３ａがＯＦＦ、３ｂがＯＮ、３ｃがＯＮ、３ｄがＯＦＦ、３ｅがＯＮ、３ｆがＯＦＦのパターンＦと、３ａがＯＦＦ、３ｂがＯＮ、３ｃがＯＮ、３ｄがＯＦＦ、３ｅがＯＦＦ、３ｆがＯＮのパターンＧと、３ａがＯＦＦ、３ｂがＯＮ、３ｃがＯＦＦ、３ｄがＯＮ、３ｅがＯＦＦ、３ｆがＯＮのパターンＨである。
【００６８】
逆位相の場合のタイミングチャートを図６に示す。図６に示すように、交流電源Ｖｉｎが正の半周期時で、かつ双方向インバータ１の出力電圧Ｖｏｕｔが負の半周期の時、モードは４パターンある。スイッチング素子３ａがＯＮ、３ｂがＯＦＦ、３ｃがＯＦＦ、３ｄがＯＮ、３ｅがＯＦＦ、３ｆがＯＮのパターンＡと、３ａがＯＮ、３ｂがＯＦＦ、３ｃがＯＮ、３ｄがＯＦＦ、３ｅがＯＦＦ、３ｆがＯＮのパターンＢと、３ａがＯＮ、３ｂがＯＦＦ、３ｃがＯＮ、３ｄがＯＦＦ、３ｅがＯＮ、３ｆがＯＦＦのパターンＣと、３ａがＯＦＦ、３ｂがＯＮ、３ｃがＯＦＦ、３ｄがＯＮ、３ｅがＯＦＦ、３ｆがＯＮのパターンＤである。また、交流電源Ｖｉｎが負の半周期で、かつ双方向インバータ１の出力電圧Ｖｏｕｔが正の半周期の時、同様にモードは４パターンある。スイッチング素子３ａがＯＮ、３ｂがＯＦＦ、３ｃがＯＮ、３ｄがＯＦＦ、３ｅがＯＮ、３ｆがＯＦＦのパターンＥと、３ａがＯＦＦ、３ｂがＯＮ、３ｃがＯＮ、３ｄがＯＦＦ、３ｅがＯＮ、３ｆがＯＦＦのパターンＦと、３ａがＯＦＦ、３ｂがＯＮ、３ｃがＯＦＦ、３ｄがＯＮ、３ｅがＯＮ、３ｆがＯＦＦのパターンＧと、３ａがＯＦＦ、３ｂがＯＮ、３ｃがＯＦＦ、３ｄがＯＮ、３ｅがＯＦＦ、３ｆがＯＮのパターンＨである。
【００６９】
同位相の時に、双方向インバータ１の出力電圧目標値が出力限界値を超えている場合、すなわちフルブリッジインバータ専用アーム６の変調率が１あるいは−１を超えている場合は、変調率の超過分△ｍをフルブリッジコンバータ専用アーム４の変調率ｍ＿ｃｎｖとコンバータ／インバータ共通アーム５の変調率ｍ＿ｃｏｍから減算あるいは加算する。この減算あるいは加算した変調率からスイッチング素子３ａ〜３ｆを制御することにより、フルブリッジコンバータの入力電圧Ｖｃｎｖ、フルブリッジインバータの出力電圧Ｖｉｎｖは目標とする電圧にすることができる。また逆位相の時に、双方向インバータ１の出力電圧目標値が出力限界値を超えている場合、すなわちフルブリッジインバータ専用アーム６の変調率が１あるいは−１を超えている場合は、変調率の超過分△ｍをフルブリッジコンバータ専用アーム４の変調率ｍ＿ｃｎｖとコンバータ／インバータ共通アーム５の変調率ｍ＿ｃｏｍから減算あるいは加算する。この減算あるいは加算した変調率からスイッチング素子３ａ〜３ｆを制御することにより、Ｖｃｎｖ、Ｖｉｎｖは目標とする電圧にすることができる。
【００７０】
以上のように本実施例によれば、同位相、逆位相共にインバータ出力電圧目標値が出力限界値を超えた場合に変調率を加算、減算することによりインバータ出力電圧は目標とする電圧を出力することができる。
【００７１】
（実施例３）
以下、本発明の第３実施例（実施例５〜８に対応）について、図７〜図９を参照しながら説明する。
【００７２】
なお、第１及び第２実施例と同一部分には同一番号を付し、その詳細な説明は省略する。
【００７３】
図７に示すように節電装置１０は、図１に示す双方向インバータ１の一方を直列変圧器１１の２次側巻線に、もう一方を交流電源に接続している。図において商用負荷１２に供給される負荷電源電圧Ｖｒは、交流電源電圧Ｖｉｎ、直列変圧器１１の変圧比を１０：１、双方向インバータ１の出力電圧をＶｉｎｖとすると、式７で示すことができる。
【００７４】
【式７】

【００７５】
図８では、交流電源電圧２１４Ｖｒｍｓ、出力設定電圧１９０Ｖｒｍｓ、直列変圧器１１の変圧比は約１０：１、また直流電圧Ｖｄｃは３８０Ｖ、負荷条件は抵抗負荷５Ωにて個別の変調率で制御した一例である。双方向インバータ１の出力電圧ピーク値は直流電圧Ｖｄｃの３８０Ｖまで可能となっており、すなわち商用負荷１２に供給する負荷電源電圧Ｖｒは約１９０Ｖｒｍｓの目標電圧となっている。
【００７６】
図９では、交流電源電圧１８２Ｖｒｍｓ、出力設定電圧１９０Ｖｒｍｓ、直列変圧器１１の変圧比は約１０：１、また直流電圧Ｖｄｃは３８０Ｖ、負荷条件は抵抗負荷５Ωにて個別の変調率で制御した一例である。双方向インバータ１の出力電圧ピーク値は直流電圧Ｖｄｃの３８０Ｖから交流電源電圧１８２Ｖｒｍｓを減算し、ピーク値は約１１８Ｖまで可能となっており、商用負荷１２に供給する負荷電源電圧Ｖｒは約１９０Ｖｒｍｓの目標電圧となっている。
【００７７】
以上のように本実施例によれば、交流電源に対して双方向インバータは同位相、逆位相共に電圧出力が可能とすることができ、直列変圧器により交流電源の電圧制御範囲がより広範囲とすることができる。
【００７８】
【発明の効果】
以上の実施例から明らかなように本発明によれば、スイッチング素子と逆並列したダイオードを上下に直列接続した第一アーム、第二アーム、第三アームと、前記第一アーム、第二アーム、第三アーム、コンデンサを相互に並列に接続し、交流電源と第一アームのダイオードの直列接続点との間、及び負荷と第三アームのダイオードの直列接続点との間にそれぞれ配したリアクトルを有する双方向インバータを構成し、前記第一アーム、第二アーム、第三アームはそれぞれフルブリッジコンバータ専用アーム、コンバータ／インバータ共通アーム、インバータ専用アームとして、それぞれが個別の変調率で動作する構成とすることで、電力損失が少なく、安価に、かつ交流電源に対して双方向インバータからの電圧出力を同位相、逆位相のインバータ電圧出力を可能とし、スイッチング素子のデューティ変化を滑らかにすることで、入力電流の歪みを抑え、フィルタ用のリアクトルの小型、軽量化と、入力電流の歪みを抑え、高精度のゼロクロス検出を必要とせず、低コストを可能とすることができるという効果のあるインバータ制御方法を提供できる。
【００７９】
また、フルブリッジコンバータ専用アームの上アームとコンバータ／インバータ共通アームの下アーム、及びフルブリッジコンバータ専用アームの下アームとコンバータ／インバータ共通アームの上アームが同一変調率あるいは互いに符号を反転させた変調率で制御している状態において、双方向インバータの出力電圧目標値がインバータ出力電圧限界を超えた場合に同一変調率あるいは互いに符号を反転させた変調率から個別の変調率に変更する構成とすることで、３つのアームのそれぞれを個別の変調率で動作させることで、電力損失が少なく、安価に、かつ交流電源に対して双方向インバータからの広範囲の電圧出力を同位相、逆位相のインバータ電圧出力を可能とし、スイッチング素子のデューティ変化を滑らかにすることで、入力電流の歪みを抑え、フィルタ用のリアクトルの小型、軽量化と、入力電流の歪みを抑え、高精度のゼロクロス検出を必要とせず、低コストを可能とすることができるという効果のあるインバータ制御方法を提供できる。
【００８０】
さらに、フルブリッジコンバータ専用アームの上アームとコンバータ／インバータ共通アームの下アーム、及びフルブリッジコンバータ専用アームの下アームとコンバータ／インバータ共通アームの上アームが同一変調率あるいは互いに符号を反転させた変調率で制御している状態において、双方向インバータの交流電源と同相の出力電圧目標値がインバータ出力電圧限界を超えた場合に、フルブリッジコンバータ専用アームの上アームとコンバータ／インバータ共通アームの下アームは、同一変調率あるいは互いに符号を反転させた変調率から個別の変調率に変更する構成とすることで、インバータの出力電圧目標値がインバータ出力電圧限界を超えた際に３つのアームのそれぞれを個別の変調率で動作させることで、同位相、逆位相のインバータ電圧出力を可能とし、インバータ出力電圧範囲を拡大することが可能とすることができるという効果のあるインバータ制御方法を提供できる。
【００８１】
また、フルブリッジコンバータ専用アームの上アームとコンバータ／インバータ共通アームの下アーム、及びフルブリッジコンバータ専用アームの下アームとコンバータ／インバータ共通アームの上アームが同一変調率あるいは互いに符号を反転させた変調率で制御している状態において、双方向インバータの交流電源と逆相の出力電圧目標値がインバータ出力電圧限界を超えた場合に、フルブリッジコンバータ専用アームの上アームとコンバータ／インバータ共通アームの下アームは、同一変調率あるいは互いに符号を反転させた変調率から個別の変調率に変更する構成とすることで、インバータの出力電圧目標値がインバータ出力電圧限界を超えた際に３つのアームのそれぞれを個別の変調率で動作させることで、同位相、逆位相のインバータ電圧出力を可能とし、インバータ出力電圧範囲を拡大することが可能とすることができるという効果のあるインバータ制御方法を提供できる。
【００８２】
さらに、節電装置において、交流電源と負荷の間に１次巻線を配した直列変圧器と、出力側が前記直列変圧器の２次巻線に接続された双方向インバータを備え、前記双方向インバータにより前記負荷に印加する電圧を制御する節電装置において、前記双方向インバータは、スイッチング素子と逆並列したダイオードを上下に直列接続した第一アーム、第二アーム、第三アームと、前記第一アーム、第二アーム、第三アーム、コンデンサを相互に並列に接続し、交流電源と第一アームのダイオードの直列接続点との間、及び負荷と第三アームのダイオードの直列接続点との間にそれぞれ配したリアクトルを有する双方向インバータを構成し、前記第一アーム、第二アーム、第三アームはそれぞれフルブリッジコンバータ専用アーム、コンバータ／インバータ共通アーム、インバータ専用アームとして、それぞれが個別の変調率で動作する構成とすることで、３つのアームのそれぞれを個別の変調率で動作させることで、電力損失が少なく、安価に、かつ交流電源に対して双方向インバータからの電圧出力を同位相、逆位相のインバータ電圧出力を可能とし、スイッチング素子のデューティ変化を滑らかにすることで、入力電流の歪みを抑え、フィルタ用のリアクトルの小型、軽量化と、入力電流の歪みを抑え、高精度のゼロクロス検出を必要とせず、低コストを可能とするインバータ制御方法を用いたことで、交流電源の電圧低下が発生した際には昇圧し、電圧上昇が発生した際には降圧する効果のある節電装置を提供できる。
【００８３】
また、節電装置において、フルブリッジコンバータ専用アームの上アームとコンバータ／インバータ共通アームの下アーム、及びフルブリッジコンバータ専用アームの下アームとコンバータ／インバータ共通アームの上アームが同一変調率あるいは互いに符号を反転させた変調率で制御している状態において、双方向インバータの出力電圧目標値がインバータ出力電圧限界を超えた場合に同一変調率あるいは互いに符号を反転させた変調率から個別の変調率に変更する構成とすることで、双方向インバータの出力電圧目標値が双方向インバータ出力電圧限界を超えた際に３つのアームのそれぞれを個別の変調率で動作させることで、同位相、逆位相の双方向インバータからの出力電圧を可能とし、インバータ出力電圧範囲を拡大する、すなわち節電装置の昇降電圧範囲を拡大することができるという効果のあるインバータ制御方法を用いた節電装置を提供できる。
【００８４】
さらに、節電装置において、フルブリッジコンバータ専用アームの上アームとコンバータ／インバータ共通アームの下アーム、及びフルブリッジコンバータ専用アームの下アームとコンバータ／インバータ共通アームの上アームが同一変調率あるいは互いに符号を反転させた変調率で制御している状態において、双方向インバータの交流電源と同相の出力電圧目標値がインバータ出力電圧限界を超えた場合に、フルブリッジコンバータ専用アームの上アームとコンバータ／インバータ共通アームの下アームは、同一変調率あるいは互いに符号を反転させた変調率から個別の変調率に変更する構成とすることで、双方向インバータの出力電圧目標値が双方向インバータ出力電圧限界を超えた際に３つのアームのそれぞれを個別の変調率で動作させることで、同位相、逆位相の双方向インバータからの出力電圧を可能とし、インバータ出力電圧範囲を拡大する、すなわち節電装置の昇降電圧範囲を拡大することができるという効果のあるインバータ制御方法を用いた節電装置を提供できる。
【００８５】
また、節電装置において、フルブリッジコンバータ専用アームの上アームとコンバータ／インバータ共通アームの下アーム、及びフルブリッジコンバータ専用アームの下アームとコンバータ／インバータ共通アームの上アームが同一変調率あるいは互いに符号を反転させた変調率で制御している状態において、双方向インバータの交流電源と逆相の出力電圧目標値がインバータ出力電圧限界を超えた場合に、フルブリッジコンバータ専用アームの上アームとコンバータ／インバータ共通アームの下アームは、同一変調率あるいは互いに符号を反転させた変調率から個別の変調率に変更する構成とすることで、双方向インバータの出力電圧目標値が双方向インバータ出力電圧限界を超えた際に３つのアームのそれぞれを個別の変調率で動作させることで、同位相、逆位相の双方向インバータ電圧出力を可能とし、双方向インバータ出力電圧範囲を拡大する、すなわち節電装置の昇降電圧幅を拡大することができるという効果のあるインバータ制御方法を用いた節電装置を提供できる。
【図面の簡単な説明】
【図１】 本発明の実施例１におけるインバータの回路図
【図２】 同インバータ出力（同位相）のタイミングチャート
【図３】 同インバータ出力（逆位相）のタイミングチャート
【図４】 同タイミングチャート拡大図
【図５】 本発明の実施例２における同位相時のタイミングチャート
【図６】 同逆位相時のタイミングチャート
【図７】 本発明の実施例３における節電装置の構成図
【図８】 節電装置の降圧制御波形例を示す図
【図９】 同節電装置の昇圧制御波形例を示す図
【図１０】 従来のインバータ装置の一例を示す電気回路ブロック図
【図１１】 同降圧時のタイミングチャート
【図１２】 同昇圧時のタイミングチャート
【符号の説明】
１ 双方向インバータ
２ ダイオード
３ スイッチング素子
４ フルブリッジコンバータ専用アーム
５ コンバータ／インバータ共通アーム
６ フルブリッジインバータ専用アーム
７ リアクトル
８ 負荷
９ コンデンサ
１０ 節電装置
１１ 直列変圧器
１２ 商用負荷[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a method for controlling an inverter including a motor, and a method for controlling an inverter in a household or business power saving apparatus having a function of reducing an excessive voltage of an AC power source and reducing power consumption.
[0002]
[Prior art]
  In recent years, it has been possible to effectively use power and save energy from the viewpoint of preventing environmental destruction and global warming. In addition, it is possible to stabilize the supplied voltage, protect the terminal, and reduce the cost of the circuit configuration. There is a demand for an inverter control method that can realize the above.
[0003]
  A conventional inverter control method of this type will be described with reference to FIGS.
[0004]
  FIG. 10 shows a step-up / step-down power regulator described in Japanese Patent Laid-Open No. 10-42559, in which first to third series circuits composed of diodes 101a and 101b, 101c and 101d, and 101e and 101f are arranged in parallel. Switching elements 201a to 201f are connected in reverse parallel to the diodes 101a to 101f of the three-phase bridge circuit configured to be connected, and one of the AC power supplies 401 is connected from the connection point of the first series circuit via the reactor 301a. The terminal is connected to one terminal of the load 501 from the connection point of the third series circuit via the reactor 301b, and the other terminal of the load 501 is connected to the connection point of the second series circuit, respectively. Furthermore, a capacitor 601c is placed between the + and-poles of the three-phase bridge circuit, and in parallel with the AC power supply 401 and the load 501. Re capacitor 601a, which are connected to 601b. In such a configuration, an arbitrary output having the same phase and voltage amplitude, that is, a step-up operation and a step-down operation are realized with respect to the AC power supply by the control method as shown in the timing charts of FIGS.
[0005]
[Problems to be solved by the invention]
  In such a conventional inverter control method, there is a problem that only an output voltage having the same phase as that of the AC power supply can be obtained.
[0006]
  In addition, since the distortion of the input current is large, there is a problem that the reactor for the filter is large and the apparatus is increased in size and weight.
[0007]
  Furthermore, since the duty change of the switching element is large in the vicinity of the zero cross of the AC power supply, the zero cross detection is required to be highly accurate for control and there is a problem that the cost increases.
[0008]
  Also, when combined with a transformer, that is, when the inverter control method is applied to a power saving device, the AC power supply can only be controlled by boosting or stepping down, and stable power supply to the load side cannot be achieved. There is.
[0009]
  The present invention solves the above-mentioned problems, and a total of three arms, that is, six switching elements, reduce power loss, is inexpensive, and outputs the voltage output from the bidirectional inverter to the AC power source in phase and in reverse. It is a first object to provide an inverter control method capable of outputting phases.
[0010]
  The second object is to provide an inverter control method capable of smoothing a duty change of a switching element, suppressing distortion of an input current, and enabling a filter reactor to be reduced in size and weight.
[0011]
  The third object is to provide a low-cost inverter control method that smoothes the duty change of the switching element, suppresses distortion of the input current, does not require highly accurate zero cross detection, and is low in cost.
[0012]
  The fourth purpose is to use an inverter control method capable of outputting positive and negative phase inverter voltage to the AC power supply. When the voltage drop of the AC power supply occurs, the voltage is increased and when the voltage increase occurs. An object of the present invention is to provide a power saving device with a function of stepping down.
[0013]
[Means for Solving the Problems]
  In order to achieve the above object, the inverter control method of the present invention includes a first arm, a second arm, a third arm, and a first arm, a second arm, and a diode that are connected in series with a switching element and an antiparallel diode. A third arm and a capacitor are connected in parallel to each other, and reactors are arranged between the AC power supply and the series connection point of the diode of the first arm and between the load and the series connection point of the diode of the third arm. The first arm, the second arm, and the third arm are configured as a full bridge converter dedicated arm, a converter / inverter common arm, and an inverter dedicated arm, respectively.The upper arm of the full-bridge converter arm and the lower arm of the converter / inverter common arm, and the lower arm of the full-bridge converter arm and the upper arm of the converter / inverter common arm have the same modulation rate or modulation rates with the signs reversed. In the controlled state, when the output voltage target value in phase with the AC power supply of the bidirectional inverter exceeds the inverter output voltage limit, the upper arm of the full bridge converter dedicated arm and the lower arm of the converter / inverter common arm are Change from the same modulation rate or modulation rates with opposite signs to individual modulation rates by subtracting or adding the excess of the modulation rate from the modulation rate of the full bridge converter dedicated arm and the modulation rate of the converter / inverter common arm Inverter control method characterized byIt is what.
[0014]
  According to the present invention, by operating each of the three arms at an individual modulation rate, the power loss is low, the cost is low, and the voltage output from the bidirectional inverter is in-phase and anti-phase with respect to the AC power supply. By enabling inverter voltage output and smoothing the duty change of the switching element, distortion of the input current is suppressed, and the filter reactor is reduced in size and weight, and distortion of the input current is suppressed, and high-precision zero-cross detection is achieved. It is not necessary, and low cost can be realized.
[0015]
  In addition, the upper arm of the full bridge converter arm and the lower arm of the converter / inverter common arm, and the lower arm of the full bridge converter arm and the upper arm of the converter / inverter common arm have the same modulation rate or modulation with the signs reversed. When the output voltage target value of the bidirectional inverter exceeds the inverter output voltage limit in a state controlled by the rate, the modulation rate is changed from the same modulation rate or the modulation rate with the signs reversed to the individual modulation rate. Is.
[0016]
  According to the present invention, by operating each of the three arms at individual modulation rates, the power loss is low, the cost is low, and the wide-range voltage output from the bidirectional inverter is in-phase and reverse with respect to the AC power supply. Enables phase inverter voltage output and smoothes the duty change of the switching element, thereby suppressing distortion of the input current, reducing the size and weight of the filter reactor, and suppressing distortion of the input current, and highly accurate zero crossing Detection is not required and low cost can be achieved.
[0017]
  In addition, the upper arm of the full bridge converter arm and the lower arm of the converter / inverter common arm, and the lower arm of the full bridge converter arm and the upper arm of the converter / inverter common arm have the same modulation rate or modulation with the signs reversed. When the output voltage target value in the same phase as the AC power supply of the bidirectional inverter exceeds the inverter output voltage limit in the state controlled by the rate, the upper arm of the full bridge converter arm and the lower arm of the converter / inverter common arm Is a configuration in which the modulation rate is changed from the modulation rate with the same modulation rate or the signs inverted from each other to an individual modulation rate.
[0018]
  According to the present invention, when the output voltage target value of the inverter exceeds the inverter output voltage limit, each of the three arms is operated at an individual modulation rate, thereby enabling in-phase and anti-phase inverter voltage output. The inverter output voltage range can be expanded.
[0019]
  In addition, the upper arm of the full bridge converter arm and the lower arm of the converter / inverter common arm, and the lower arm of the full bridge converter arm and the upper arm of the converter / inverter common arm have the same modulation rate or modulation with the signs reversed. When the output voltage target value of the opposite phase to the AC power supply of the bidirectional inverter exceeds the inverter output voltage limit in the state controlled by the rate, the upper arm of the full bridge converter dedicated arm and the converter / inverter common arm The arm is configured to change the modulation rate from the same modulation rate or the modulation rate with the signs reversed to each other.
[0020]
  According to the present invention, when the output voltage target value of the inverter exceeds the inverter output voltage limit, each of the three arms is operated at an individual modulation rate, thereby enabling in-phase and anti-phase inverter voltage output. The inverter output voltage range can be expanded.
[0021]
  further,A series transformer having a primary winding disposed between an AC power supply and a load, and a bidirectional inverter having an output side connected to the secondary winding of the series transformer are applied to the load by the bidirectional inverter. In the power-saving device for controlling the voltage, the bidirectional inverter includes a first arm, a second arm, a third arm, and a first arm, a second arm, Three arms, capacitors connected in parallel with each other, and reactors arranged between the AC power supply and the series connection point of the diode of the first arm and between the load and the series connection point of the diode of the third arm A bidirectional inverter is constructed, and the first arm, the second arm, and the third arm are the full-bridge converter dedicated arm, the converter / inverter common arm, As a converter dedicated arm,The upper arm of the full-bridge converter arm and the lower arm of the converter / inverter common arm, and the lower arm of the full-bridge converter arm and the upper arm of the converter / inverter common arm have the same modulation rate or modulation rates with the signs reversed. In the controlled state, when the output voltage target value in phase with the AC power supply of the bidirectional inverter exceeds the inverter output voltage limit, the upper arm of the full bridge converter dedicated arm and the lower arm of the converter / inverter common arm are From the same modulation rate or modulation rates with opposite signs, Subtract or add the excess of the modulation rate from the modulation rate of the full bridge converter arm and the modulation rate of the converter / inverter common armThe power saving device uses an inverter control method characterized by changing to an individual modulation rate.
[0022]
  According to the present invention, by operating each of the three arms at an individual modulation rate, the power loss is low, the cost is low, and the voltage output from the bidirectional inverter is in-phase and anti-phase with respect to the AC power supply. By enabling inverter voltage output and smoothing the duty change of the switching element, distortion of the input current is suppressed, and the filter reactor is reduced in size and weight, and distortion of the input current is suppressed, and high-precision zero-cross detection is achieved. By using an inverter control method that does not require low cost, a power-saving device with a function of boosting when the voltage drop of the AC power supply occurs and stepping down when the voltage rise occurs It is to provide.
[0023]
  In the power saving device, the upper arm of the full bridge converter arm and the lower arm of the converter / inverter common arm, and the lower arm of the full bridge converter arm and the upper arm of the converter / inverter common arm have the same modulation rate or the same sign. When the output voltage target value of the bidirectional inverter exceeds the inverter output voltage limit in the state where the control is performed with the inverted modulation rate, the modulation rate is changed from the same modulation rate or the modulation rate with the signs reversed to each other. It is set as the structure which carries out.
[0024]
  According to the present invention, in the power saving device, when the output voltage target value of the bidirectional inverter exceeds the limit of the bidirectional inverter output voltage, each of the three arms is operated at the individual modulation rate, so The output voltage from the phase bidirectional inverter is made possible, and the inverter output voltage range can be expanded, that is, the step-up voltage range of the power saving device can be expanded.
[0025]
  Further, in the power saving device, the upper arm of the full bridge converter dedicated arm and the lower arm of the converter / inverter common arm, and the lower arm of the full bridge converter dedicated arm and the upper arm of the converter / inverter common arm have the same modulation rate or the same sign. When the output voltage target value in the same phase as the AC power supply of the bidirectional inverter exceeds the inverter output voltage limit when the inverter is controlled at the inverted modulation rate, the upper arm of the full-bridge converter arm and the converter / inverter are common The lower arm of the arm is configured to change the modulation rate from the same modulation rate or the modulation rate with the signs reversed to each other.
[0026]
  According to the present invention, when the output voltage target value of the bidirectional inverter exceeds the limit of the bidirectional inverter output voltage in the power saving device, each of the three arms is operated at the individual modulation rate. The output voltage from the bidirectional inverter can be increased, and the inverter output voltage range can be expanded, that is, the step-up voltage range of the power saving device can be expanded.
[0027]
  In the power saving device, the upper arm of the full bridge converter arm and the lower arm of the converter / inverter common arm, and the lower arm of the full bridge converter arm and the upper arm of the converter / inverter common arm have the same modulation rate or the same sign. When the output voltage target value in the opposite phase to the AC power supply of the bidirectional inverter exceeds the inverter output voltage limit when the inverter is controlled with the inverted modulation rate, the upper arm of the full bridge converter arm and the converter / inverter The lower arm of the common arm is configured to change the modulation rate from the same modulation rate or the modulation rate with the signs reversed to each other.
[0028]
  According to the present invention, in the power saving device, when the output voltage target value of the bidirectional inverter exceeds the limit of the bidirectional inverter output voltage, each of the three arms is operated at the individual modulation rate, so The bidirectional inverter voltage output of the phase can be realized, and the bidirectional inverter output voltage range can be expanded, that is, the step-up voltage width of the power saving device can be expanded.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
  In order to achieve the above object, the inverter control method of the present invention includes a first arm, a second arm, a third arm, and a first arm, a second arm, and a diode that are connected in series with a switching element and an antiparallel diode. A third arm and a capacitor are connected in parallel to each other, and reactors are arranged between the AC power supply and the series connection point of the diode of the first arm and between the load and the series connection point of the diode of the third arm. The first arm, the second arm, and the third arm are configured as a full bridge converter dedicated arm, a converter / inverter common arm, and an inverter dedicated arm, respectively.Full-bridge converter upper arm, converter / inverter common arm lower arm, and full-bridge converter Output voltage target value in the same phase as the AC power supply of the bi-directional inverter when the lower arm of the inverter dedicated arm and the upper arm of the converter / inverter common arm are controlled at the same modulation rate or the modulation rate with the signs reversed. When the inverter output voltage limit is exceeded, the upper arm of the full-bridge converter dedicated arm and the lower arm of the converter / inverter common arm will detect the excess of the modulation rate based on the same modulation rate or the modulation rate with the signs reversed. Inverter control method characterized by changing to individual modulation rate subtracted or added from modulation rate of full bridge converter dedicated arm and modulation rate of converter / inverter common armBy doing so, the distortion of the input current can be suppressed, the filter reactor can be made smaller and lighter, and the distortion of the input current can be suppressed. Have
[0030]
  In addition, the upper arm of the full bridge converter arm and the lower arm of the converter / inverter common arm, and the lower arm of the full bridge converter arm and the upper arm of the converter / inverter common arm have the same modulation rate or modulation with the signs reversed. When the output voltage target value of the bidirectional inverter exceeds the inverter output voltage limit in a state controlled by the rate, the modulation rate is changed from the same modulation rate or the modulation rate with the signs reversed to the individual modulation rate. By operating each of the three arms at individual modulation rates, the power loss is low, the cost is low, and a wide-range voltage output from the bidirectional inverter is in-phase and anti-phase inverter with respect to the AC power supply. Enables voltage output and smoothes the duty change of the switching element. Suppressing the distortion of the flow, with a small reactor for the filter, and light weight, preventing distortion of input current, without requiring high precision of the zero-cross detection, the effect that it is possible to enable a low cost.
[0031]
  In addition, the upper arm of the full bridge converter arm and the lower arm of the converter / inverter common arm, and the lower arm of the full bridge converter arm and the upper arm of the converter / inverter common arm have the same modulation rate or modulation with the signs reversed. When the output voltage target value in the same phase as the AC power supply of the bidirectional inverter exceeds the inverter output voltage limit in the state controlled by the rate, the upper arm of the full bridge converter arm and the lower arm of the converter / inverter common arm Is configured to change the modulation rate from the same modulation rate or the modulation rate with the signs inverted to individual modulation rates, so that when the inverter output voltage target value exceeds the inverter output voltage limit, each of the three arms By operating at individual modulation rates, in-phase and anti-phase To allow the converter voltage output, such an action may be possible to enlarge the inverter output voltage range.
[0032]
  In addition, the upper arm of the full bridge converter arm and the lower arm of the converter / inverter common arm, and the lower arm of the full bridge converter arm and the upper arm of the converter / inverter common arm have the same modulation rate or modulation with the signs reversed. When the output voltage target value of the opposite phase to the AC power supply of the bidirectional inverter exceeds the inverter output voltage limit in the state controlled by the rate, the upper arm of the full bridge converter dedicated arm and the converter / inverter common arm The arm is configured to change the modulation rate from the same modulation rate or the modulation rate with the signs reversed to the individual modulation rate, so that when the output voltage target value of the inverter exceeds the inverter output voltage limit, each of the three arms By operating at different modulation rates, It possible to over-Capacitor Voltage output, an effect that may be possible to enlarge the inverter output voltage range.
[0033]
  further,A series transformer having a primary winding disposed between an AC power supply and a load, and a bidirectional inverter having an output side connected to the secondary winding of the series transformer are applied to the load by the bidirectional inverter. In the power-saving device for controlling the voltage, the bidirectional inverter includes a first arm, a second arm, a third arm, and a first arm, a second arm, Three arms, capacitors connected in parallel to each other, AC A bidirectional inverter having a reactor arranged between the power source and the series connection point of the diode of the first arm and between the load and the series connection point of the diode of the third arm is configured. The second arm and the third arm are a full-bridge converter arm, a converter / inverter common arm, and an inverter arm, respectively.The upper arm of the full-bridge converter arm and the lower arm of the converter / inverter common arm, and the lower arm of the full-bridge converter arm and the upper arm of the converter / inverter common arm have the same modulation rate or modulation rates with the signs reversed. In the controlled state, when the output voltage target value in phase with the AC power supply of the bidirectional inverter exceeds the inverter output voltage limit, the upper arm of the full bridge converter dedicated arm and the lower arm of the converter / inverter common arm are From the same modulation rate or modulation rates with opposite signs, Subtract or add the excess of the modulation rate from the modulation rate of the full bridge converter arm and the modulation rate of the converter / inverter common armIt is characterized by changing to individual modulation rateRuReduced input current distortion, reduced filter current reactor size and weight, reduced input current distortion, and does not require high-accuracy zero-cross detection. By using the inverter control method that enables the power supply, it is possible to provide a power saving device with a function of increasing the voltage when the voltage drop of the AC power supply occurs and decreasing the voltage when the voltage increase occurs. Has an effect.
[0034]
  In the power saving device, the upper arm of the full bridge converter arm and the lower arm of the converter / inverter common arm, and the lower arm of the full bridge converter arm and the upper arm of the converter / inverter common arm have the same modulation rate or the same sign. When the output voltage target value of the bidirectional inverter exceeds the inverter output voltage limit in the state where the control is performed with the inverted modulation rate, the modulation rate is changed from the same modulation rate or the modulation rate with the signs reversed to each other. With this configuration, when the output voltage target value of the bi-directional inverter exceeds the bi-directional inverter output voltage limit, each of the three arms is operated at an individual modulation rate, so that both in-phase and anti-phase are operated. Enables output voltage from the inverter, and expands the inverter output voltage range. An effect that it is possible to enlarge the elevator voltage range of the power saving device.
[0035]
  Further, in the power saving device, the upper arm of the full bridge converter dedicated arm and the lower arm of the converter / inverter common arm, and the lower arm of the full bridge converter dedicated arm and the upper arm of the converter / inverter common arm have the same modulation rate or the same sign. When the output voltage target value in the same phase as the AC power supply of the bidirectional inverter exceeds the inverter output voltage limit when the inverter is controlled at the inverted modulation rate, the upper arm of the full-bridge converter arm and the converter / inverter are common The lower arm of the arm is configured to change to the individual modulation rate from the same modulation rate or the modulation rate with the signs reversed, so that the output voltage target value of the bidirectional inverter exceeded the bidirectional inverter output voltage limit Each of the three arms is operated at a separate modulation rate. In Rukoto, has the effect of a possible output voltage from the same phase, reverse phase bi-directional inverter, expanding the inverter output voltage range, that is, to expand the lifting voltage range of the power saving device.
[0036]
  In the power saving device, the upper arm of the full bridge converter arm and the lower arm of the converter / inverter common arm, and the lower arm of the full bridge converter arm and the upper arm of the converter / inverter common arm have the same modulation rate or the same sign. When the output voltage target value in the opposite phase to the AC power supply of the bidirectional inverter exceeds the inverter output voltage limit when the inverter is controlled with the inverted modulation rate, the upper arm of the full bridge converter arm and the converter / inverter The lower arm of the common arm is configured to change to the individual modulation rate from the same modulation rate or the modulation rate with the signs reversed, so that the output voltage target value of the bidirectional inverter exceeds the limit of the bidirectional inverter output voltage. Each of the three arms is operated at a separate modulation rate. It is, has an effect of the same phase, and enables bidirectional inverter voltage output of the inverse phase, expanding the bidirectional inverter output voltage range, that is, to increase the lifting voltage width of the power-saving device.
[0037]
【Example】
  Embodiments of the present invention will be described below with reference to the drawings.
[0038]
  Example 1
  Hereinafter, a first embodiment of the present invention (corresponding to the first embodiment) will be described with reference to FIGS.
[0039]
  FIG. 1 shows a circuit diagram of the bidirectional inverter 1. In the figure, a switching element 3a is connected in reverse parallel to the diode 2a, a switching element 3b is connected in reverse parallel to the diode 2b, a diode 2a connected in reverse parallel to the switching element 3a, and a diode 2b connected in reverse parallel to the switching element 3b. Are connected in series in the vertical direction to form a full bridge converter dedicated arm 4 as a first arm. The switching element 3c is connected in antiparallel with the diode 2c, the switching element 3d is connected in antiparallel with the diode 2d, the diode 2c connected in antiparallel with the switching element 3c, and the diode 2d connected in antiparallel with the switching element 3d The converter / inverter common arm 5 is formed as a second arm by connecting in series. The switching element 3e is connected in antiparallel with the diode 2e, the switching element 3f is connected in antiparallel with the diode 2f, the diode 2e connected in antiparallel with the switching element 3e, and the diode 2f connected in antiparallel with the switching element 3f A full bridge inverter dedicated arm 6 is formed as a third arm by connecting in series. Furthermore, the connection point between the diodes 2a and 2b is connected to the reactor 7a, the connection point between the diodes 2c and 2d is connected to the reactor 7b, and the connection point between the reactor 7c and the diodes 2e and 2f is connected to the reactor 7d. Further, the reactors 7 a and 7 b are connected to an AC power source, and the reactors 7 c and 7 d are connected to a load 8. The capacitor 9a is connected to the AC power supply side of the reactors 7a and 7b, the capacitor 9b is connected to the load 8 side of the reactors 7c and 7d, and the capacitor 9c is connected to the cathode side of the diode 2a and the anode side of the diode 2b. To do.
[0040]
  In the circuit of FIG. 1, the case where each arm operates at an individual modulation rate will be described.
[0041]
  Under the above conditions, the duty of the switching element 3a of the full-bridge converter dedicated arm 4 is D1, the duty of the switching element 3b of the full-bridge converter dedicated arm 4 is 1-D1, and the duty of the switching element 3c of the converter / inverter common arm 5 is D2 and the duty of switching element 3d of converter / inverter common arm 5 are 1-D2, the duty of switching element 3e of full-bridge inverter dedicated arm 6 is D3, and the duty of switching element 3f of full-bridge inverter dedicated arm 6 is 1- If the combined reactance of D3 and reactors 7a and 7b is L1, and the combined reactance of reactors 7c and 7d is L2, the AC power supply voltage Vin is calculated as shown in Equation 1 and the voltage Vout on the load 8 side is calculated as shown in Equation 2. Rukoto can. However, dead time is ignored.
[0042]
[Formula 1]

[0043]
[Formula 2]

[0044]
  Vdc is a DC link voltage of the voltage across the capacitor 9c, i1 is a current flowing through the reactors 7a and 7b, and i2 is a current flowing through the reactors 7c and 7d. Here, regarding the control flow of the modulation rate control means that controls with individual modulation rates, the switching pattern is divided into two cases, when the AC power supply Vin and the output voltage Vout of the bidirectional inverter 1 are in the same phase and in the opposite phase. explain.
[0045]
  A timing chart in the case of the same phase is shown in FIG. As shown in FIG. 2, the comparison between the modulation factor of each arm and the carrier wave is defined, and each of the AC power supply Vin and the output voltage Vout of the bidirectional inverter 1 is a positive half cycle, and the alternating current power supply Vin is the bidirectional inverter 1. When the output voltage Vout is larger than the output voltage Vout, there are four modes. Switching element 3a is ON, 3b is OFF, 3c is OFF, 3d is ON, 3e is OFF, 3f is ON, pattern A, 3a is ON, 3b is OFF, 3c is OFF, 3d is ON, 3e is ON, Pattern B with 3f OFF, 3a ON, 3b OFF, 3c ON, 3d OFF, 3e OFF, 3f OFF Pattern C, 3a OFF, 3b ON, 3c OFF, 3d OFF ON, 3e is OFF, and 3f is ON. Further, when each of the AC power supply Vin and the output voltage Vout of the bidirectional inverter 1 has a negative half cycle, there are four modes in the same manner. Switching element 3a is OFF, 3b is ON, 3c is ON, 3d is OFF, 3e is ON, 3f is OFF, pattern E, 3a is ON, 3b is OFF, 3c is ON, 3d is OFF, 3e is ON, Pattern F with 3f OFF, 3a OFF, 3b ON, 3c ON, 3d OFF, 3e OFF, 3f ON pattern G, 3a OFF, 3b ON, 3c OFF, 3d The pattern H is ON, 3e is OFF, and 3f is ON.
[0046]
  A timing chart in the case of an antiphase is shown in FIG. As shown in FIG. 3, when the AC power source Vin is in a positive half cycle and the output voltage Vout of the bidirectional inverter 1 is in a negative half cycle, there are four modes. Switching element 3a is ON, 3b is OFF, 3c is OFF, 3d is ON, 3e is OFF, 3f is ON, pattern A, 3a is ON, 3b is OFF, 3c is ON, 3d is OFF, 3e is OFF, Pattern B with 3f ON, 3a ON, 3b OFF, 3c ON, 3d OFF, 3e ON, 3f OFF Pattern C, 3a OFF, 3b ON, 3c OFF, 3d ON, 3e is OFF, and 3f is ON. Similarly, when the AC power source Vin has a negative half cycle and the output voltage Vout of the bidirectional inverter 1 has a positive half cycle, there are four modes in the same manner. That is, the switching element 3a is ON, 3b is OFF, 3c is ON, 3d is OFF, 3e is ON, 3f is ON, pattern 3E is OFF, 3a is OFF, 3b is ON, 3c is ON, 3d is OFF, 3e is OFF ON, 3f OFF pattern F, 3a OFF, 3b ON, 3c OFF, 3d ON, 3e ON, 3f OFF pattern G, 3a OFF, 3b ON, 3c OFF, 3d is ON, 3e is OFF, and 3f is ON.
[0047]
  In the case of the same phase, the voltages of the respective parts in FIG. 1, that is, the voltage Va across the switching element 3b, the voltage Vb across the switching element 3d, and the voltage Vc across the switching element 3f are Va> Vb, Vc> Vb or Va < There are two combinations of Vb and Vc <Vb.
[0048]
  When Va> Vb and Vc> Vb, the switching element 3e is turned on while the switching elements 3a and 3d are ON while the AC power supply voltage is positive, so that the output voltage of the bidirectional inverter 1 is a positive voltage, Vc> Vb can be applied. Accordingly, by turning ON the switching element 3e while the switching elements 3a and 3d are ON, the output of the bidirectional inverter 1 in phase with the positive period of the AC power supply, that is, when Va> Vb, Vc> Vb bidirectional The output of the inverter 1 becomes possible. When Va <Vb and Vc <Vb, the switching element 3f is turned ON while the switching elements 3b and 3c are ON, so that the output of the bidirectional inverter 1 in phase with the negative period of the AC power supply, that is, Va <Vb At this time, the output of the bidirectional inverter 1 with Vc <Vb becomes possible.
[0049]
  As shown in FIG. 4, when the switching patterns of the switching elements 3a to 3f are T1 to T6, the carrier period is T, and the times from the patterns A to D are Ta to Td, in each mode at the same phase The circuit equation is Equation 3.
[0050]
[Formula 3]

[0051]
  Formula 1 is obtained by multiplying each side of Formula 3 by Td from each Ta, and calculating and organizing the sum.
[0052]
  Next, in the case of reverse phase, there are two combinations of voltages Va, Vb, and Vc in FIG. 1 such that Va> Vb and Vc <Vb or Va <Vb and Vc> Vb.
[0053]
  When Va> Vb and Vc <Vb, the switching element 3f is turned ON while the switching elements 3b and 3c are ON, so that the output voltage of the bidirectional inverter 1 becomes a negative voltage or Vc during the positive period of the AC power supply. <Vb can be applied. Accordingly, by turning on the switching element 3f while the switching elements 3b and 3c are on, the output of the bidirectional inverter 1 having an antiphase with respect to the AC power supply, that is, the bidirectional inverter of Vc <Vb when Va> Vb. 1 output is possible. In the case of Va <Vb, Vc> Vb, the switching element 3e is turned on while the switching elements 3a and 3d are on, so that the output of the bidirectional inverter 1 in reverse phase with respect to the AC power source, that is, Va <Vb. Sometimes the output of the bidirectional inverter 1 with Vc> Vb becomes possible. Equation 1 can be derived in the opposite phase as in the same phase.
[0054]
  As described above, the output voltage of the bidirectional inverter 1 can be controlled by controlling the switching elements 3a to 3f with the ON / OFF ratio in both the same phase and the opposite phase.
[0055]
  Regarding the determination method of the duty D1, D2 of the switching elements 3a-3f, since the input / output voltage of the bidirectional inverter 1 can be determined by the duty D1, D2 from the equations 1 and 2, the calculation of the duty D1, D3 is performed. If it does, it will become like Formula 4.
[0056]
[Formula 4]

[0057]
  Thus, by comparing with the carrier signal, the duties D1 to D3 are determined, and the switching elements 3a to 3f are controlled.
[0058]
  As described above, according to this embodiment, the inverter can output both in-phase and anti-phase to the AC power supply.
[0059]
  In the present embodiment, the positive logic is used when outputting the duty of each switching element from the comparison of the modulation factor of each arm and the carrier wave, but there is no difference in the effect even if the negative logic is used.
[0060]
  (Example 2)
  Hereinafter, a second embodiment (corresponding to the second to fourth embodiments) of the present invention will be described with reference to FIGS.
[0061]
  The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
[0062]
  In the circuit of FIG. 1, the output voltage target value of the bidirectional inverter 1 in a state in which each combination of the switching element 3 a and the switching element 3 d, and each combination of the switching element 3 b and the switching element 3 c is turned on with a modulation rate with the signs reversed. A case where the output voltage limit of the bidirectional inverter 1 is exceeded will be described.
[0063]
  The combination of the switching element 3a and the switching element 3d is the modulation factor m_c, the combination of the switching element 3b and the switching element 3c is the modulation factor -m_c, that is, the modulation factor obtained by inverting the sign of the combination of the switching elements 3a and 3d, and different timings. In the state of being turned on, the AC power supply voltage Vin can be calculated as shown in Equation 5, and the voltage Vout on the load 8 side can be calculated as shown in Equation 6.
[0064]
[Formula 5]

[0065]
[Formula 6]

[0066]
  Here, regarding the control flow of the modulation rate control means that controls with individual modulation rates, the switching pattern is divided into two cases, when the AC power supply Vin and the output voltage Vout of the bidirectional inverter 1 are in the same phase and in the opposite phase. explain.
[0067]
  A timing chart in the case of the same phase is shown in FIG. As shown in FIG. 5, when each of the AC power source Vin and the output voltage Vout of the bidirectional inverter 1 is a positive half cycle and Vout <Vin, the mode has the following four patterns. That is, the switching element 3a is ON, 3b is OFF, 3c is OFF, 3d is ON, 3e is OFF, 3f is ON, pattern A is 3a, 3a is ON, 3b is OFF, 3c is OFF, 3d is ON, 3e is ON, 3f OFF pattern B, 3a ON, 3b OFF, 3c ON, 3d OFF, 3e ON, 3f OFF pattern C, 3a OFF, 3b ON, 3c OFF, 3d is ON, 3e is OFF, and 3f is ON. Further, when each of the AC power supply Vin and the output voltage Vout of the bidirectional inverter 1 has a negative half cycle, there are four modes in the same manner. Switching element 3a is ON, 3b is OFF, 3c is ON, 3d is OFF, 3e is ON, 3f is OFF, pattern E, 3a is OFF, 3b is ON, 3c is ON, 3d is OFF, 3e is ON, Pattern F with 3f OFF, 3a OFF, 3b ON, 3c ON, 3d OFF, 3e OFF, 3f ON pattern G, 3a OFF, 3b ON, 3c OFF, 3d The pattern H is ON, 3e is OFF, and 3f is ON.
[0068]
  A timing chart in the case of an antiphase is shown in FIG. As shown in FIG. 6, when the AC power supply Vin is in the positive half cycle and the output voltage Vout of the bidirectional inverter 1 is in the negative half cycle, there are four modes. Switching element 3a is ON, 3b is OFF, 3c is OFF, 3d is ON, 3e is OFF, 3f is ON, pattern A, 3a is ON, 3b is OFF, 3c is ON, 3d is OFF, 3e is OFF, Pattern B with 3f ON, 3a ON, 3b OFF, 3c ON, 3d OFF, 3e ON, 3f OFF Pattern C, 3a OFF, 3b ON, 3c OFF, 3d ON, 3e is OFF, and 3f is ON. Similarly, when the AC power source Vin has a negative half cycle and the output voltage Vout of the bidirectional inverter 1 has a positive half cycle, there are four modes in the same manner. Switching element 3a is ON, 3b is OFF, 3c is ON, 3d is OFF, 3e is ON, 3f is OFF, pattern E, 3a is OFF, 3b is ON, 3c is ON, 3d is OFF, 3e is ON, Pattern F with 3f OFF, 3a OFF, 3b ON, 3c OFF, 3d ON, 3e ON, 3f OFF Pattern G, 3a OFF, 3b ON, 3c OFF, 3d OFF The pattern H is ON, 3e is OFF, and 3f is ON.
[0069]
  When the output voltage target value of the bidirectional inverter 1 exceeds the output limit value at the same phase, that is, when the modulation rate of the full bridge inverter dedicated arm 6 exceeds 1 or −1, the modulation rate is exceeded. The minute Δm is subtracted or added from the modulation factor m_cnv of the full bridge converter dedicated arm 4 and the modulation factor m_com of the converter / inverter common arm 5. By controlling the switching elements 3a to 3f from the subtracted or added modulation rate, the input voltage Vcnv of the full bridge converter and the output voltage Vinv of the full bridge inverter can be set to target voltages. Further, when the output voltage target value of the bidirectional inverter 1 exceeds the output limit value in the opposite phase, that is, when the modulation factor of the full-bridge inverter dedicated arm 6 exceeds 1 or -1, The excess Δm is subtracted or added from the modulation factor m_cnv of the full bridge converter dedicated arm 4 and the modulation factor m_com of the converter / inverter common arm 5. By controlling the switching elements 3a to 3f from the subtracted or added modulation rate, Vcnv and Vinv can be set to target voltages.
[0070]
  As described above, according to this embodiment, when the inverter output voltage target value exceeds the output limit value for both in-phase and anti-phase, the inverter output voltage outputs the target voltage by adding and subtracting the modulation factor. can do.
[0071]
  (Example 3)
  Hereinafter, a third embodiment (corresponding to the fifth to eighth embodiments) of the present invention will be described with reference to FIGS.
[0072]
  In addition, the same number is attached | subjected to the same part as 1st and 2nd Example, and the detailed description is abbreviate | omitted.
[0073]
  As shown in FIG. 7, the power saving apparatus 10 has one of the bidirectional inverters 1 shown in FIG. 1 connected to the secondary winding of the series transformer 11 and the other connected to an AC power source. In the figure, the load power supply voltage Vr supplied to the commercial load 12 is expressed by Equation 7 where the AC power supply voltage Vin, the transformation ratio of the series transformer 11 is 10: 1, and the output voltage of the bidirectional inverter 1 is Vinv. it can.
[0074]
[Formula 7]

[0075]
  In FIG. 8, an example in which the AC power supply voltage is 214 Vrms, the output setting voltage is 190 Vrms, the transformation ratio of the series transformer 11 is about 10: 1, the DC voltage Vdc is 380 V, and the load conditions are controlled by individual modulation rates with a resistance load of 5Ω. It is. The output voltage peak value of the bidirectional inverter 1 can be up to 380 V of the DC voltage Vdc, that is, the load power supply voltage Vr supplied to the commercial load 12 is a target voltage of about 190 Vrms.
[0076]
  In FIG. 9, an example in which the AC power supply voltage is 182 Vrms, the output set voltage is 190 Vrms, the transformation ratio of the series transformer 11 is about 10: 1, the DC voltage Vdc is 380 V, and the load condition is controlled by individual modulation rates with a resistance load of 5Ω. It is. The output voltage peak value of the bidirectional inverter 1 is obtained by subtracting the AC power supply voltage 182 Vrms from the DC voltage Vdc of 380 V, and the peak value can be up to about 118 V. The load power supply voltage Vr supplied to the commercial load 12 is about 190 Vrms. The target voltage is reached.
[0077]
  As described above, according to this embodiment, the bidirectional inverter can output voltage in both the same phase and the opposite phase with respect to the AC power supply, and the voltage control range of the AC power supply can be broadened by the series transformer. can do.
[0078]
【The invention's effect】
  As is clear from the above embodiments, according to the present invention, the first arm, the second arm, the third arm, and the first arm, the second arm, and the first arm, which are connected in series with the diode in reverse parallel to the switching element, A third arm and a capacitor are connected in parallel to each other, and reactors are arranged between the AC power supply and the series connection point of the diode of the first arm and between the load and the series connection point of the diode of the third arm. A bidirectional inverter having the first arm, the second arm, and the third arm as a full-bridge converter dedicated arm, a converter / inverter common arm, and an inverter dedicated arm, each operating at an individual modulation rate, and By doing so, the power output from the bidirectional inverter is reduced in phase and in phase with respect to the AC power source with low power loss and low cost. Enables the output of a barter voltage and smoothes the duty change of the switching element to suppress distortion of the input current, reducing the size and weight of the reactor for the filter, and suppressing the distortion of the input current to achieve highly accurate zero cross detection. It is possible to provide an inverter control method that is not required and that can achieve low cost.
[0079]
  In addition, the upper arm of the full bridge converter arm and the lower arm of the converter / inverter common arm, and the lower arm of the full bridge converter arm and the upper arm of the converter / inverter common arm have the same modulation rate or modulation with the signs reversed. When the output voltage target value of the bidirectional inverter exceeds the inverter output voltage limit in a state controlled by the rate, the modulation rate is changed from the same modulation rate or the modulation rate with the signs reversed to the individual modulation rate. By operating each of the three arms at individual modulation rates, the power loss is low, the cost is low, and a wide-range voltage output from the bidirectional inverter is in-phase and anti-phase inverter with respect to the AC power supply. Enables voltage output and smoothes the duty change of the switching element. Inverter control method that has the effect of reducing current distortion, reducing the size and weight of the filter reactor, reducing distortion of the input current, and eliminating the need for highly accurate zero-cross detection and enabling low cost. Can provide.
[0080]
  In addition, the upper arm of the full bridge converter arm and the lower arm of the converter / inverter common arm, and the lower arm of the full bridge converter arm and the upper arm of the converter / inverter common arm have the same modulation rate or modulation with the signs reversed. When the output voltage target value in the same phase as the AC power supply of the bidirectional inverter exceeds the inverter output voltage limit in the state controlled by the rate, the upper arm of the full bridge converter arm and the lower arm of the converter / inverter common arm Is configured to change the modulation rate from the same modulation rate or the modulation rate with the signs inverted to individual modulation rates, so that when the inverter output voltage target value exceeds the inverter output voltage limit, each of the three arms By operating at individual modulation rates, in-phase and anti-phase To allow the converter voltage output, can provide an inverter control method is effective in that it can be possible to enlarge the inverter output voltage range.
[0081]
  In addition, the upper arm of the full bridge converter arm and the lower arm of the converter / inverter common arm, and the lower arm of the full bridge converter arm and the upper arm of the converter / inverter common arm have the same modulation rate or modulation with the signs reversed. When the output voltage target value of the opposite phase to the AC power supply of the bidirectional inverter exceeds the inverter output voltage limit in the state controlled by the rate, the upper arm of the full bridge converter dedicated arm and the converter / inverter common arm The arm is configured to change the modulation rate from the same modulation rate or the modulation rate with the signs reversed to the individual modulation rate, so that when the output voltage target value of the inverter exceeds the inverter output voltage limit, each of the three arms By operating at different modulation rates, It possible to over-Capacitor Voltage output, can provide an inverter control method is effective in that it can be possible to enlarge the inverter output voltage range.
[0082]
  The power saving device further includes a series transformer in which a primary winding is arranged between an AC power supply and a load, and a bidirectional inverter having an output side connected to the secondary winding of the series transformer, the bidirectional inverter In the power-saving device that controls the voltage applied to the load by the first and second arms, the bidirectional inverter includes a first arm, a second arm, a third arm, and a first arm that are connected in series with a diode in antiparallel with a switching element. , Second arm, third arm, capacitor connected in parallel to each other, between the AC power source and the series connection point of the diode of the first arm, and between the load and the series connection point of the diode of the third arm A bidirectional inverter having a reactor arranged in each case is constructed, and the first arm, the second arm, and the third arm are a full bridge converter dedicated arm and a converter, respectively. The inverter common arm and inverter dedicated arm are configured to operate at individual modulation rates, so that each of the three arms operates at individual modulation rates, resulting in low power loss, low cost, and AC The voltage output from the bidirectional inverter to the power supply can be output in the same or opposite phase, and the duty change of the switching element is made smooth, so that distortion of the input current is suppressed and the filter reactor is compact. By using an inverter control method that reduces weight, suppresses distortion of the input current, does not require high-precision zero-cross detection, and enables low cost, it boosts the voltage when the AC power supply voltage drops. When the voltage rises, it is possible to provide a power saving device that has an effect of reducing the voltage.
[0083]
  In the power saving device, the upper arm of the full bridge converter arm and the lower arm of the converter / inverter common arm, and the lower arm of the full bridge converter arm and the upper arm of the converter / inverter common arm have the same modulation rate or the same sign. When the output voltage target value of the bidirectional inverter exceeds the inverter output voltage limit in the state where the control is performed with the inverted modulation rate, the modulation rate is changed from the same modulation rate or the modulation rate with the signs reversed to each other. With this configuration, when the output voltage target value of the bi-directional inverter exceeds the bi-directional inverter output voltage limit, each of the three arms is operated at an individual modulation rate, so that both in-phase and anti-phase are operated. Enables output voltage from the inverter, and expands the inverter output voltage range. Possible to provide a power saving device using the inverter control method is effective in that it is possible to enlarge the elevator voltage range of the power saving device.
[0084]
  Further, in the power saving device, the upper arm of the full bridge converter dedicated arm and the lower arm of the converter / inverter common arm, and the lower arm of the full bridge converter dedicated arm and the upper arm of the converter / inverter common arm have the same modulation rate or the same sign. When the output voltage target value in the same phase as the AC power supply of the bidirectional inverter exceeds the inverter output voltage limit when the inverter is controlled at the inverted modulation rate, the upper arm of the full-bridge converter arm and the converter / inverter are common The lower arm of the arm is configured to change to the individual modulation rate from the same modulation rate or the modulation rate with the signs reversed, so that the output voltage target value of the bidirectional inverter exceeded the bidirectional inverter output voltage limit Each of the three arms is operated at a separate modulation rate. Therefore, an inverter control method that has the effect of enabling the output voltage from the in-phase and anti-phase bidirectional inverters to expand the inverter output voltage range, that is, to expand the step-up voltage range of the power saving device. The power saving device used can be provided.
[0085]
  In the power saving device, the upper arm of the full bridge converter arm and the lower arm of the converter / inverter common arm, and the lower arm of the full bridge converter arm and the upper arm of the converter / inverter common arm have the same modulation rate or the same sign. When the output voltage target value in the opposite phase to the AC power supply of the bidirectional inverter exceeds the inverter output voltage limit when the inverter is controlled with the inverted modulation rate, the upper arm of the full bridge converter arm and the converter / inverter The lower arm of the common arm is configured to change to the individual modulation rate from the same modulation rate or the modulation rate with the signs reversed, so that the output voltage target value of the bidirectional inverter exceeds the limit of the bidirectional inverter output voltage. Each of the three arms is operated at a separate modulation rate. Therefore, it is possible to output bidirectional inverter voltages in the same phase and in opposite phases, and use an inverter control method that has the effect of expanding the bidirectional inverter output voltage range, that is, expanding the step-up voltage range of the power saving device. It is possible to provide a power saving device.
[Brief description of the drawings]
FIG. 1 is a circuit diagram of an inverter according to a first embodiment of the present invention.
Fig. 2 Timing chart of same inverter output (same phase)
FIG. 3 is a timing chart of the same inverter output (reverse phase)
FIG. 4 is an enlarged view of the same timing chart
FIG. 5 is a timing chart at the same phase in Embodiment 2 of the present invention.
FIG. 6 is a timing chart at the opposite phase.
FIG. 7 is a configuration diagram of a power saving device according to a third embodiment of the present invention.
FIG. 8 is a diagram illustrating a step-down control waveform example of the power saving device
FIG. 9 is a diagram showing an example of a boost control waveform of the power saving device
FIG. 10 is an electric circuit block diagram showing an example of a conventional inverter device.
FIG. 11 is a timing chart at the same step-down time.
FIG. 12 is a timing chart at the same boosting time.
[Explanation of symbols]
  1 Bidirectional inverter
  2 Diode
  3 Switching elements
  4 Full-bridge converter arm
  5 Converter / inverter common arm
  6 Full-bridge inverter arm
  7 Reactor
  8 Load
  9 Capacitor
  10 Power saving device
  11 Series transformer
  12 Commercial load

Claims (4)

A first arm, a second arm, and a third arm that are connected in series with a diode in reverse parallel to the switching element, and the first arm, the second arm, the third arm, and a capacitor are connected in parallel to each other, and an AC power supply A bidirectional inverter having a reactor disposed between the load and the series connection point of the diode of the first arm and between the load and the series connection point of the diode of the third arm, respectively. The arm and the third arm are the full bridge converter dedicated arm, the converter / inverter common arm, and the inverter dedicated arm, respectively, the upper arm of the full bridge converter dedicated arm, the lower arm of the converter / inverter common arm, and the full bridge converter dedicated arm. The upper arm of the arm and the converter / inverter common arm have the same modulation rate. Or when the output voltage target value in phase with the AC power supply of the bidirectional inverter exceeds the inverter output voltage limit in the state where the control is performed with the modulation rate with the signs reversed, the upper arm of the full bridge converter dedicated arm The lower arm of the converter / inverter common arm subtracts the excess of the modulation rate from the modulation rate of the full-bridge converter dedicated arm and the modulation rate of the converter / inverter common arm from the same modulation rate or from the modulation rate with the signs reversed. Or the inverter control method characterized by changing to the added individual modulation rate.   The upper arm of the full bridge converter arm and the lower arm of the converter / inverter common arm, and the lower arm of the full bridge converter arm and the upper arm of the converter / inverter common arm have the same modulation rate or modulation rates with the signs reversed. In the controlled state, when the output voltage target value opposite to the AC power supply of the bidirectional inverter exceeds the inverter output voltage limit, the upper arm of the full bridge converter arm and the lower arm of the converter / inverter common arm 2. The inverter control method according to claim 1, wherein the modulation rate is changed from the same modulation rate or a modulation rate with the signs inverted to an individual modulation rate. A series transformer having a primary winding disposed between an AC power supply and a load, and a bidirectional inverter having an output side connected to the secondary winding of the series transformer are applied to the load by the bidirectional inverter. In the power-saving device for controlling the voltage, the bidirectional inverter includes a first arm, a second arm, a third arm, and a first arm, a second arm, Three arms, capacitors connected in parallel with each other, and reactors arranged between the AC power supply and the series connection point of the diode of the first arm and between the load and the series connection point of the diode of the third arm A bidirectional inverter is constructed, and the first arm, the second arm, and the third arm are the full-bridge converter dedicated arm, the converter / inverter common arm, As converter dedicated arms, full bridge converter dedicated arm and the converter / inverter common arm of the lower arm on the arm, and the full-bridge converter dedicated arm on the lower arm and the converter / inverter common arm of the arm by the same modulation rate, or together inverting the sign When the output voltage target value in the same phase as the AC power supply of the bidirectional inverter exceeds the inverter output voltage limit when controlled by the controlled modulation rate, the upper arm of the full bridge converter arm and the converter / inverter common arm The lower arm is an individual modulation obtained by subtracting or adding the excess of the modulation rate from the modulation rate of the full-bridge converter dedicated arm and the modulation rate of the converter / inverter common arm from the same modulation rate or the modulation rate with the signs reversed. Characterized by changing rate Power saving device using Louis inverter control method. The upper arm of the full-bridge converter arm and the lower arm of the converter / inverter common arm, and the lower arm of the full-bridge converter arm and the upper arm of the converter / inverter common arm have the same modulation rate or modulation rates with the signs reversed. In the controlled state, when the output voltage target value opposite to the AC power supply of the bidirectional inverter exceeds the inverter output voltage limit, the upper arm of the full bridge converter arm and the lower arm of the converter / inverter common arm 4. The power-saving device using the inverter control method according to claim 3, wherein the modulation rate is changed from the same modulation rate or the modulation rates having the signs inverted to each other to individual modulation rates.

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