【０００１】
【発明の属する技術分野】
放電管を点灯制御する電子安定器に関する
【０００２】
【従来の技術】
高輝度、高出力のガス入り放電管の点灯回路は交流電源にトランス、チョークコイルによる所謂インピーダンスの電圧制御の銅鉄型の安定器で、その形状および重量も大きく、、電源電圧の変動により大幅に光束、消費電力が変動する等の不安定性や管電圧に適合のためのチョーク、トランス銅損鉄損等のロスの大きさは高輝度、大電力、多灯数使用する場合の省エネ性には問題があるものの、その回路装置の簡便さとから、いまのところ古典的なこの銅鉄型が大半を占めているのが現状である。また最近小ワットの電子安定器も出現し始めているが、なにぶん高周波駆動なので発生ノイズ、高調波発生等の問題で本来必要とされる、大出力型のもの４００Ｗ以上のものは、更にノイズも大きくて、発熱、防湿等の対策費のコストアップ、折角高周波によるスイッチングロスが銅鉄型の鉄損、銅損よりましなものの、その実用化普及には今一歩の現状である。
【０００３】
【発明が解決しようとする課題】
これらを改善すべく、さきに特開平９−８２４８１号、特開平１０−１３４９８２号等で提案した直流チョッパー方式のものや脈流点灯制御装置もあるが（図２）それらは簡便、安価な回路であり、動作基本はＤＣ脈流であり、またかなり低い周波数でチョッパーするのでノイズ発生レベルも問題にならない程度まで低減可能であり、低い周波数でチョッパーするのでスイチングロスも発熱も低く効率も高い。発光効率ルーメンパーワツトで言えば銅鉄型安定器の水銀灯と比べ１９％は確実に高効率で（公的機関の成績表）、なおかつ大幅な自由調光機能と相まって放電管安定器として完成度は高いが、唯一弱点としてその回路は動作上ＰＷＭ電流検知の直流チョッパーによる、一方通行の放電であるため、直流放電管か同様構造で電極の頑丈さと管内電蝕の起きにくい封入ガスの選択等の管への直流対策をしたまたは改造した放電管が必要であつた。これらを従来からの交流点灯用の水銀灯、メタハラ管を使用しても、管へのダメージ問題のなく点灯制御できることが要望されてきた。
折角の小型、軽量、自動出力制御可能、大幅な自由調光、高効率、多数灯の同時制御等も簡単に可能という、数々の時代の要求にマッチした合理的省エネ的制御機能をもちながら惜しいことであった。本発明の回路はその問題を解決し従来の一般交流管をもＰＷＭ安定器の各機能を落とさず、かつ管にもマイルドな使用可能な安定器の開発が課題であった。
【０００４】
【課題を解決するための手段】
本発明は本発明の構成上の特徴は、前述したような電流検知制御のチョッパー型ＰＷＭスイッチング回路の発生する可変直流電圧の電流制御モードの電源をば、次の低周波で駆動するフルブリジ型インバーターの電源に接続、その負荷に交流放電管を接続し極性を低周波の期間（３０Ｈｚから５００Ｈｚ）でスイッチ回路として放電管極性を短時間で切り替えることによって基本の点灯制御回路であるＰＷＭスイッチ回路の優れた機能、つまり大幅な照度、電力制御（１０％から１５０％）、低ノイズ性、高効率、省エネ性等の各性能を全く損なわずに従来の交流用水銀灯、メタハラ管等全てを管へのストレス無く安定した点灯制御が可能になった。
【０００５】
【発明の実施の形態】
本発明の作用をまず説明すると制御基本のＰＷＭ定電流制御するチョッパー回路（図２）の作用は放電管の通電開始から管温度上昇に伴う放電電流増加に対応して、自動可変インピーダンス作用するチョークコイル的動作をするともいえる、つまり負特性放電管抵抗に対応する効率のよい直流の電子チョーク機能を発揮するといえる。しかも銅鉄型安定器の銅損、鉄損のエネルギーロスに比べてかなり少ないスイッチングロスで点灯制御出来るのである、またＰＷＭで電流制御し電力、照度を下げ調光するとＰＷＭでパルス巾狭くなるにつれて出力電圧が自動的に上がるので、（図２のＡ点波形は図３のＡ）今までの安定器では考えられない照度、電力とも最低１０％まで下げても安定に点灯継続する。（降圧型チョッパーのインダクタンス７．とＡ点のダイオードとの効用）そこでこの可変するＰＷＭ波形脈流ＤＣ出力（図２のＢ点図３のＢ１，Ｂ２は制御時の波形）の＋−を放電管でなくフルブリジインバーターの＋−に接続し統合したのが、本発明の電子安定器１図である。そしてそのスイッチングを４０Ｈｚから２００Ｈｚ位の低周波で１図のフルブリジのＦＥＴ１１及びＦＥＴ１４をＦＥＴ１２及びＦＥＴ１３を交互に切り替え、その出力部に接続した放電管６の電流の向き、つまり極性を切り替える。（第１図矢印点線矢印の方向交互）これらを統合した全体回路図が第１図である、この回路により従来の交流放電管を使用して先述した直流ＰＷＭチョツパーの電子チョークの性能をそのまま充分に発揮することが可能になった。なお類似的な回路として第４図のごとくフルブリッジでＦＥＴの１１、１２を４０ＫＨｚ、１３、１４を１００Ｈｚで駆動する回路もあるが、この回路では定電流の制御は出来ても、フルブリジ電源＋−は一定では大幅調光は不可能であり制御系も発振複数個必要で複雑になるうえ、小型とはいえ電圧制御用のチョークコイル１９（９ｍＨ以上）にて放電管の電圧維持のためインピーダンス制御も必要であり、ロスもその分かなり増える。この回路は銅鉄型安定器が５０ＨＺだったものが、５０ＫＨｚになっただけで本発明とは別の原理駆動バージョンである。まだ交流的制御の域をでないと考えられる。本発明は基本の制御の直流ＰＷＭ回路がブリッジ回路及びその負荷である放電管をも制御するシステムである。
【０００６】
【発明の効果】
本発明の基本の放電管の制御機能である直流ＰＭＷ点灯制御のもつ前記したように１９％も高効率の省エネ性よく、さらに大幅な調光機能もそのまま生かし、従来ある通常の交流用放電管、水銀灯、ばかりかメタハラ放電管、ハロゲン放電灯も問題なく点灯可能になった。（簡単なパルス回路付加は必要）そのため既設の交流管はそのままで本安定器の設置可能になった。低い周波数でフルブリッジをオンオフすることと、スイッチ素子の最近のＦＥＴのオン抵抗の低下（２５０Ｖ耐圧で０．１オーム）等の性能向上によりロスも発熱も僅少である。
（図３）のＢ１，Ｂ２波形のよう直流のリップル波形であるために数百ボルトの交流制御よりノイズの押さえ込みも楽である。またさらに自由広範囲の調光特性を生かし、朝夕の点灯時、簡単なＣＤＳセンサーで外光を取り入れ、暗くなると照明が段々明るくなり、また朝明るくなると段々暗くなる自動節電調光も可能、又放電管は点灯初期の管温の低いとき一番ストレスが懸かるので点滅を繰り返す程管寿命が半減する事が知られている。そのため点灯初期に自動調光して初期の２分間、５０％のソフトスタートさせ管にマイルド寿命延長につながる。昼休み又は幕間など消さなくとも１０％の照度にして時間がくれば２分で１００％になる５０％の時３０秒で１００％、６０％の時１０秒、等の動作をさせることも可能。また高輝度放電管は通常管寿命末期には照度５０％まで低下しますが、今度は調光を１２０％に上げて必要照度を保つことも可能、またいままで普通水銀灯のところ、同ワットのメタハラ管に変え、同一照度に調光すると５０％近い節電にも可能でなる。今まで貴方任せの銅鉄型安定器による放電管照明であつたものが、必要な時必要な照度という合理的省エネ的使用法ができ、安定器交換するだけで既設の交流放電管回路でも可能になった。また直流放電時には起きやすい放電アークの細いシヤープ化も防ぐことも出来た。ともあれ本安定器は単純な交流、ノイズ多大な高周波点灯では無く、マイルドなＤＣ脈流を交互に放電管に加えた高効率の電子安定器なのである。
【図面の簡単な説明】
【図１】本発明の放電管電子安定器
【図２】基本ＰＷＭ直流駆動回路
【図３】基本駆動回路各部出力波形
【図４】従来の類似的回路
【符号の説明】
１は電源
２はＰＷＭ駆動ＦＥＴ
３はＰＷＭ駆動ＩＣ（１０ＫＨｚＴＬ４９４等）
４はフォトカプラー
５は電流検知オペアンプ
６は放電管
７はチョッパー用コイル
８は電流検知用抵抗
９は基準電圧
１０は調光、出力制御ＶＲ
１１はフルブリッジのスイッチＦＥＴ（フローティング）１４と連動
１２はフルブリッジスイッチのＦＥＴ（フローティング）１３と連動
１３はフルブリッジスイッチのＦＥＴ１２と連動
１４はフルブリッジスイッチのＦＥＴ１１と連動
１５は駆動用フォトカプラー（出力アース線記入省略）
１６は駆動用フォトカプラー（出力アース線記入省略）
１７は駆用動フォトカプラー２回路独立（出力アース線記入省略）
１８はフルブリッジ切替発振ＩＣ（交互２回路発振、デッドタイム出力、低周波）
１９は電圧降下安定用インピーダンス（８ｍＨ以上）[0001]
TECHNICAL FIELD OF THE INVENTION
[0002] The present invention relates to an electronic ballast for controlling lighting of a discharge tube.
[Prior art]
The lighting circuit of the high-intensity, high-output gas-filled discharge tube is a so-called impedance-controlled, copper-iron type ballast with a transformer and a choke coil for the AC power supply, and its shape and weight are large. Instability such as fluctuation of luminous flux and power consumption, choke for adaptation to tube voltage, loss of transformer copper loss, iron loss, etc. are important for high brightness, large power, and energy saving when multiple lamps are used. Although there is a problem, at present, the classic copper-iron type occupies the majority because of the simplicity of the circuit device. Recently, electronic ballasts with small watts have also begun to appear. However, the high-power type 400 W or more, which is originally required due to problems such as noise generation and harmonic generation due to high frequency driving, has higher noise. However, although the cost of countermeasures such as heat generation and moisture prevention is increased, and the switching loss due to the high frequency is better than the iron loss and copper loss of the copper-iron type, it is just one step toward its practical use.
[0003]
[Problems to be solved by the invention]
In order to improve these, there are DC chopper type and pulsating flow lighting control devices proposed in Japanese Patent Application Laid-Open Nos. 9-82481 and 10-134982 (FIG. 2), but they are simple and inexpensive circuits. The operation is basically a DC pulsating flow, and since the chopper is performed at a considerably low frequency, the noise generation level can be reduced to a level that does not cause any problem. Since the chopper is performed at a low frequency, switching efficiency, heat generation is low, and efficiency is high. Luminous Efficiency Speaking of lumen lumens, 19% is definitely higher in efficiency than the mercury lamp of copper-iron type ballast (the result table of a public organization), and combined with a large free dimming function, completeness as a discharge tube ballast The only weak point is that the circuit is a one-way discharge using a DC chopper for detecting the PWM current in operation. It was necessary to provide a discharge tube with a DC countermeasure for the tube or a modified one. Even if a conventional mercury lamp for AC lighting or a meta-hara tube is used, it has been demanded that the lighting can be controlled without a problem of damage to the tube.
Small size, light weight, automatic output control, large free dimming, high efficiency, easy control of multiple lights at the same time. Was that. The problem of the circuit of the present invention is to solve the problem and to develop a ballast which can use a conventional general AC tube without reducing the functions of the PWM ballast and which can be used mildly for the tube.
[0004]
[Means for Solving the Problems]
The present invention is characterized in that a full bridge type inverter driven at the following low frequency is provided by using a power supply in a variable DC voltage current control mode generated by a chopper type PWM switching circuit for current detection control as described above. Of the PWM switch circuit, which is a basic lighting control circuit, by connecting an AC discharge tube to the load and switching the polarity of the discharge tube in a short time as a switch circuit during a low frequency period (30 Hz to 500 Hz). Excellent functions, such as large illuminance, power control (10% to 150%), low noise, high efficiency, energy saving, etc. Lighting control is now possible without stress.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
First, the operation of the present invention will be described. The operation of the chopper circuit (FIG. 2) for controlling the PWM constant current, which is a basic control method, is a choke which performs an automatic variable impedance operation in response to an increase in the discharge current due to a rise in the tube temperature from the start of energizing the discharge tube. It can be said that it operates like a coil, that is, it exhibits an efficient DC electronic choke function corresponding to the negative characteristic discharge tube resistance. In addition, the lighting can be controlled with much less switching loss than the copper loss and iron loss energy of the copper-iron type ballast. Also, when the power and the illuminance are reduced by controlling the current with PWM and the pulse width becomes narrower with PWM when dimming is performed. Since the output voltage is automatically increased (the waveform at point A in FIG. 2 is A in FIG. 3), the illuminance and the electric power, which cannot be considered in the conventional ballast, are stably maintained even when the illuminance and the power are reduced to at least 10%. (Effect of the inductance 7. of the step-down chopper and the diode at the point A) Then, this variable PWM waveform pulsating DC output (points B and B2 in FIG. 2 and points B1 and B2 in FIG. 3 at the time of control) discharges + and-. An electronic ballast 1 according to the present invention is connected to and integrated with +-of a full bridge inverter instead of a tube. The switching is performed at a low frequency of about 40 Hz to about 200 Hz by alternately switching the full bridge FET 11 and the FET 14 between the FET 12 and the FET 13 and switching the direction of the current of the discharge tube 6 connected to the output portion, that is, the polarity. FIG. 1 shows an overall circuit diagram in which these components are integrated. The circuit shown in FIG. 1 uses the conventional AC discharge tube to sufficiently improve the performance of the electronic choke of the DC PWM chopper described above. It became possible to demonstrate. As a similar circuit, as shown in FIG. 4, there is a circuit that drives FETs 11 and 12 at 40 KHz and 13 and 14 at 100 Hz using a full bridge. If-is constant, large dimming is impossible and the control system requires a plurality of oscillations, which makes it complicated. In addition, although the size is small, the impedance is maintained by the choke coil 19 (9 mH or more) for voltage control to maintain the voltage of the discharge tube. Control is also required, and the loss increases considerably. This circuit is a principle-driven version different from the present invention in that the copper-iron type ballast is 50 HZ, but only at 50 KHz. It is not considered to be in the area of AC control yet. The present invention is a system in which a DC PWM circuit for basic control also controls a bridge circuit and a discharge tube as a load thereof.
[0006]
【The invention's effect】
As described above, the DC PWM lighting control, which is the basic control function of the discharge tube of the present invention, has a high efficiency of 19% and good energy saving, and further utilizes the large dimming function as it is. , Mercury lamps, meta-hara discharge tubes, and halogen discharge lamps can be turned on without any problems. (It is necessary to add a simple pulse circuit.) Therefore, the ballast can be installed without changing the existing AC pipe. The loss and heat generation are small due to the performance improvement such as the on / off of the full bridge at a low frequency and the recent reduction in the ON resistance of the switching element (0.1 ohm at 250 V withstand voltage).
Since it is a DC ripple waveform like the B1 and B2 waveforms in FIG. 3, it is easier to suppress noise than AC control of several hundred volts. In addition, taking advantage of the light control characteristics of a wide range of freedom, a simple CDS sensor takes in external light when lighting in the morning and evening, and the lighting gradually becomes brighter when it gets darker, and it automatically darkens when it gets brighter in the morning. It is known that the life of a tube is halved as the tube repeats blinking because the tube is most stressed when the tube temperature is low at the beginning of lighting. Therefore, the dimming is automatically performed at the beginning of lighting, and the soft start of 50% is performed for the first two minutes, thereby extending the mild life of the tube. Even if you don't turn off the lights during lunch break or during the intermission, you can set 100% in 2 minutes if you have 10% illuminance. In the case of high-intensity discharge tubes, the illuminance usually drops to 50% at the end of the life of the tube, but this time it is possible to increase the dimming to 120% to maintain the required illuminance. By changing to a meta-hara tube and dimming to the same illuminance, it is possible to save power by nearly 50%. What used to be the discharge tube lighting using a copper-iron ballast that you can use can be used in a reasonable energy-saving manner, requiring the required illuminance when needed, and the existing AC discharge tube circuit can be used simply by replacing the ballast Became. Also, it was possible to prevent the discharge arc from becoming thin and sharp during the DC discharge. Anyway, this ballast is not a simple alternating current and high frequency lighting with a lot of noise, but a high efficiency electronic ballast in which a mild DC pulsating current is alternately applied to the discharge tube.
[Brief description of the drawings]
FIG. 1 is a discharge tube electronic ballast of the present invention. FIG. 2 is a basic PWM DC drive circuit. FIG. 3 is an output waveform of each part of the basic drive circuit. FIG. 4 is a conventional similar circuit.
1 is power supply 2 is PWM drive FET
3 is a PWM drive IC (10 kHz TL494, etc.)
4 is a photocoupler 5 is a current detection operational amplifier 6 is a discharge tube 7 is a chopper coil 8 is a current detection resistor 9 is a reference voltage 10 is dimming and output control VR
11 is a full bridge switch FET (floating) 14 and interlocking 12 is a full bridge switch FET (floating) 13 and interlocking 13 is a full bridge switch FET 12 and interlocking 14 is a full bridge switch FET 11 and interlocking 15 is a driving photocoupler (Omission of output ground wire)
16 is a drive photocoupler (output earth wire omitted)
17 is a drive dynamic photocoupler 2 circuit independent (output earth wire is omitted)
18 is a full-bridge switching oscillation IC (alternate two-circuit oscillation, dead time output, low frequency)
19 is a voltage drop stabilizing impedance (8 mH or more)
