JP3583208B2

JP3583208B2 - Switching power supply

Info

Publication number: JP3583208B2
Application number: JP25183995A
Authority: JP
Inventors: 実田中; 晴夫渡辺; 豊関根
Original assignee: Shindengen Electric Manufacturing Co Ltd
Current assignee: Shindengen Electric Manufacturing Co Ltd
Priority date: 1995-09-05
Filing date: 1995-09-05
Publication date: 2004-11-04
Anticipated expiration: 2015-09-05
Also published as: JPH0974762A

Description

【０００１】
【発明の属する技術分野】
本発明は、交流を入力とするスイッチング式直流安定化電源装置の力率改善に関するものである。
【０００２】
【従来の技術】
図１は、特開平７−１５９６７で開示されている力率改善型スイッチング電源の基本回路図である。
この技術は１組のスイッチング素子と制御回路からなる簡単な構成で高力率、高効率な交流入力スイッチング電源を提供することを目的とするものである。
【０００３】
構成は交流電源１に接続された全波整流器２、３、４、５の直流出力に平滑コンデンサ８を接続し、該平滑コンデンサ８の端子間にトランス７の１次巻線Ｎ１とスイッチ素子９の直列回路を接続し、該トランス７の２次巻線Ｎ２に、ダイオ −ド１０、１１、リアクトル１２及びコンデンサ１３から成る整流平滑回路を接続して出力側の負荷に電力を供給するスイッチング電源に於いて、全波整流器２、３、４、５の直流出力側の一端に、インダクタ６とトランス７の制御巻線Ｎ３の直列回路を接続して、平滑コンデンサ８の一端に接続する様に構成されている。
【０００４】
その動作は、スイッチ素子９がオン期間に、平滑コンデンサ８のエネルギ−はトランス７に蓄えられ、スイッチ素子７がオフの期間にトランス７に蓄えられたエネルギ−が、トランス７の２次側Ｎ２より整流平滑回路を介して負荷に送られる。
これと同時にインダクタ６の電流はトランス７の制御巻線Ｎ３を介して平滑コンデンサ８に流れ込み、同時に、トランス７の制御巻線Ｎ３に電流が流れた結果、トランス７の１次巻線Ｎ１と制御巻線Ｎ３との巻数比に対応する電流が、トランス７の２次巻線Ｎ２より整流平滑回路を通して出力平滑コンデンサ１３に流れる。
【０００５】
即ち、スイッチ素子９がオフの期間には、インダクタ６に蓄えられていたエネルギ−が入力平滑コンデンサ８と整流平滑回路のコンデンサ１３に送られる。
【０００６】
この結果、インダクタ６に流れる電流波形ピ−ク値のエンベロ−プ（包絡線）が正弦波状をえがく為、インダクタンス６とトランス７の制御巻線Ｎ３を加えるだけで力率を改善する事が出来る。
【０００７】
さらに、スイッチ素子９がオフの期間にインダクタ６に印加される電圧は、従来の交流入力スイッチング電圧の場合は、平滑コンデンサ８の電圧と入力電圧との差電圧であるのに対し、図１の回路では平滑コンデンサ８の電圧とトランス７の制御巻線Ｎ３に発生している電圧の和から入力電圧を差し引いた値なので、インダクタ６の電流をリセットするのに必要な平滑コンデンサ８の電圧は、従来の交流入力スイッチング電源に対し、トランス７の制御巻線Ｎ３に発生する電圧分だけ低くすることが出来る。
即ち、スイッチ素子として低耐圧で、オン抵抗の小さいものを使用する事が出来るので、スイッチング電源の高効率化を図ることが出来る。
【０００８】
図２は倍電圧整流回路を使用した力率改善型スイッチング電源の一実施例である。
図１で示したスイッチング電源に対して、第２のインダクタ６′とトランス７の第２の制御巻線Ｎ４の直列回路を設けて第２の平滑コンデンサ８′の一端に接続し、平滑コンデンサ８及び８′のコモン点より、交流電源の電圧が低い場合オンさせる第２のスイッチ素子１４を設けて、倍電圧入力回路を構成している。
【０００９】
交流電源１の電圧が低い場合は第２のスイッチ素子１４をオンさせる。
これにより、正の半サイクルでは、交流電源１→ダイオ−ド２→インダクタ６→制御巻線Ｎ３→平滑コンデンサ８→第２のスイッチ素子１４→ダイオ−ド５→交流電源１のル−トで電流が流れ、負の半サイクルでは、交流電源１→第２のスイッチ素子１４→第２の平滑コンデンサ８′→第２の制御巻線Ｎ４→第２のインダクタ６′→ダイオ−ド４→交流電源１のル−トで電流が流れる。
【００１０】
これによって平滑コンデンサ８及び８′はそれぞれ交流入力電圧のピ−ク値で充電される為、全波整流した場合の二倍の入力電圧を得ることが出来る。
【００１１】
尚交流電源１の電圧が高い場合は、第２のスイッチ素子１４をオフさせれば単なる全波整流回路となる。
【００１２】
力率改善に関するインダクタ及び制御巻線の動作は前述の図１の場合とほぼ同様であるので説明は省略する。
【００１３】
【発明が解決しようとする課題】
これまで述べた従来技術は、入力側整流回路にインダクタとトランス制御巻線の直列回路を設けるだけで力率改善及び高効率化が実現出来る点では非常に有効な回路である。
【００１４】
しかし、交流入力電圧が、例えば変動許容範囲内で急激に上昇した場合、力率改善用に設けたインダクタ及びトランスの制御巻線が逆に弊害となってしまう。すなわち、入力電圧急変により、図１の入力整流後の電圧（Ａ点）と平滑コンデンサ８の電圧（Ｂ点）との間に電位差が発生し、インダクタ６とトランスの制御巻線Ｎ３の直列インピ−ダンスで除した過大な電流が流れる。
【００１５】
この電流はトランス７の制御巻線Ｎ３から１次巻線Ｎ１に、巻数比に応じて誘起され、その結果スイッチ素子９に過大な電流が流れ、素子を破損させるおそれがある。
【００１６】
又、スイッチ素子９と直列に電流検出回路が設けてある場合は、通常動作状態であるにも拘らず、過電流として検出して垂下状態となり、出力電圧を大幅に低下させてしまうおそれがある。
これらの要因によって、電源システムの信頼性を低下させてしまう原因ともなる。
【００１７】
従って本発明は、かかる欠点を解決する為に、入力電圧の急激な上昇に対し、入力側回路に過大な電流が流れる事を抑制し、スイッチ素子の破壊や出力電圧の低下を防止する技術を提案するものである。
【００１８】
図２の倍電圧回路の場合についても、前述と全く同様な問題点がある。
【００１９】
【課題を解決するための手段】
従って本発明は、力率改善用に設けたインダクタとトランス制御巻線の直列回路と並列にダイオ−ドを設け、入力電圧が急上昇した時に生じようとする差電圧を、入力平滑コンデンサ電圧にクランプさせる様に回路構成した事を特徴とするスイッチング電源である。
【００２０】
【実施例】
図３は、図１の従来技術に本発明の技術を適用したスイッチング電源の一実施例である。
図１と同一符号は同一名称であるので説明を省略する。
図３に於いて、インダクタ６とトランス７の制御巻線Ｎ３の直列回路と並列に、平滑コンデンサ８Ｎの充電方向にダイオ−ド１４を設けてある。
【００２１】
これによって、交流電源１の電圧が入力電圧変動範囲内で急激に上昇した場合、入力整流後の電圧（Ａ点）と平滑コンデンサ８の電圧（Ｂ点）との間に電位差が発生するが、ダイオ−ド１４により入力整流後の電圧（Ａ点）と平滑コンデンサ８の電圧（Ｂ点）との間を短絡する事により、発生しようとする電位差を速やかに低下させる。
【００２２】
この結果、インダクタ６と制御巻線Ｎ３の直列インピ−ダンスで除いた電流はほぼ零となり、従って制御巻線Ｎ３から１次巻線Ｎ１に巻線比に応じて誘起される電流も零となる。
その結果スイッチ素子９には過大電流が流れることなく、スイッチ素子９を破損させたり、過電流検出による出力電圧低下といった不具合が生ずることはなくなる。
【００２３】
図４は、図１の従来技術に本発明の技術を適用したスイッチング電源の他の実施例である。図１と同一符号は同一名称であり、交流電源１の両極から各々ダイオ−ド１５、１６を通して平滑コンデンサ８への充電ル−トを設ける事により、入力電圧急上昇時にインダクタ６及び制御巻線Ｎ３に電位差が発生しない様にしている。
動作の説明は図２の場合とほぼ同様であるので省略する。
【００２４】
図５は、図２の倍電圧入力スイッチング電源に本発明の技術を適用した第１の実施例である。図２と同一符号は同一名称であり説明は省略する。
【００２５】
インダクタ６及び制御巻線Ｎ３の直列回路に並列に、平滑コンデンサ８を充電する方向にダイオ−ド１７を設けると共に、第２のインダクタ６′及び第２の制御巻線Ｎ′の直列回路と並列に、第２の平滑コンデンサ８′を放電する方向にダイオ−ド１８が設けてある。
入力電圧急上昇時、インダクタ及び制御巻線に発生しようとする電位差をダイオ−ドによって短絡する原理については前述と同じであるので説明は省略する。
【００２６】
図６は、図２の倍電圧入力のスイッチング電源に於ける本発明の他の実施例である。この場合も図２と同一符号のものは省略するが、本発明では交流入力１の両極よりダイオ−ド１９、２０を通して、平滑コンデンサ８への充電ル−トを設けると共に、平滑コンデンサ８′からの放電ル−トをダイオ−ド２１、２２を通して交流電源１の両極にそれぞれ帰還するル−トを設けている。これにより入力電圧が急上昇した時にインダクタ６及び制御巻線Ｎ３、第２のインダクタ６′及び第２の制御巻線Ｎ４に電位差が発生しない様にしている。
【００２７】
【発明の効果】
本発明によれば、入力電圧が急激に上昇した時、スイッチ素子を破損させる事もなく、又出力電圧の低下を抑制出来る為、信頼性の高い力率改善型スイッチング電源を提供し得るものである。
【図面の簡単な説明】
【図１】従来の力率改善型スイッチング電源の一実施例
【図２】倍電圧整流回路を使用した従来の力率改善型スイッチング電源の一実施例
【図３】図１の従来型スイッチング電源に本発明技術を適用したスイッチング電源の一実施例
【図４】図１の従来型スイッチング電源に本発明技術を適用したスイッチング電源の他の実施例
【図５】図２の倍電圧入力型スイッチング電源に本発明技術を適用したスイッチング電源の一実施例
【図６】図２の倍電圧入力型スイッチング電源に本発明技術を適用したスイッチング電源の他の実施例
【符号の説明】
１交流電源
２〜５全波整流器
６インダクタ
６′ 第２のインダクタ
７トランス
８平滑コンデンサ
８′ 第２の平滑コンデンサ
９スイッチ素子
１０、１１ダイオ−ド
１２リアクトル
１３コンデンサ
１４第２のスイッチ素子
１５〜２２ダイオ−ド
Ｎ１トランス７の１次巻線
Ｎ２トランス７の２次巻線
Ｎ３トランス７の制御巻線
Ｎ４トランス７の第２の制御巻線[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to improvement of a power factor of a switching type stabilized DC power supply device having an AC input.
[0002]
[Prior art]
FIG. 1 is a basic circuit diagram of a power factor correction type switching power supply disclosed in Japanese Patent Laid-Open No. 7-15967.
The purpose of this technique is to provide a high power factor and high efficiency AC input switching power supply with a simple configuration comprising a set of switching elements and a control circuit.
[0003]
The smoothing capacitor 8 is connected to the DC outputs of the full-wave rectifiers 2, 3, 4, and 5 connected to the AC power supply 1, and the primary winding N1 of the transformer 7 and the switching element 9 are connected between the terminals of the smoothing capacitor 8. A switching power supply for supplying power to a load on the output side by connecting a rectifying and smoothing circuit comprising diodes 10, 11, a reactor 12 and a capacitor 13 to a secondary winding N2 of the transformer 7 In this case, a series circuit of an inductor 6 and a control winding N3 of a transformer 7 is connected to one end of the full-wave rectifiers 2, 3, 4, and 5 on the DC output side, and connected to one end of a smoothing capacitor 8. It is configured.
[0004]
The operation is such that the energy of the smoothing capacitor 8 is stored in the transformer 7 while the switch element 9 is on, and the energy stored in the transformer 7 while the switch element 7 is off is converted to the secondary side N2 of the transformer 7. It is sent to the load via a rectifying and smoothing circuit.
At the same time, the current of the inductor 6 flows into the smoothing capacitor 8 via the control winding N3 of the transformer 7, and at the same time, the current flows in the control winding N3 of the transformer 7, so that the primary winding N1 of the transformer 7 A current corresponding to the turn ratio with the control winding N3 flows from the secondary winding N2 of the transformer 7 to the output smoothing capacitor 13 through the rectifying and smoothing circuit.
[0005]
That is, while the switch element 9 is off, the energy stored in the inductor 6 is sent to the input smoothing capacitor 8 and the capacitor 13 of the rectifying and smoothing circuit.
[0006]
As a result, the envelope (envelope) of the current waveform peak value flowing through the inductor 6 is sinusoidal, so that the power factor can be improved only by adding the control winding N3 of the inductor 6 and the transformer 7. .
[0007]
Further, the voltage applied to the inductor 6 while the switch element 9 is off is a difference voltage between the voltage of the smoothing capacitor 8 and the input voltage in the case of a conventional AC input switching voltage, whereas the voltage of FIG. In the circuit, since the input voltage is subtracted from the sum of the voltage of the smoothing capacitor 8 and the voltage generated in the control winding N3 of the transformer 7, the voltage of the smoothing capacitor 8 required to reset the current of the inductor 6 is The voltage can be reduced by the voltage generated in the control winding N3 of the transformer 7 as compared with the conventional AC input switching power supply.
That is, since a switch element having a low withstand voltage and a small on-resistance can be used as the switch element, the efficiency of the switching power supply can be increased.
[0008]
FIG. 2 shows an embodiment of a power factor improving type switching power supply using a voltage doubler rectifier circuit.
For the switching power supply shown in FIG. 1, a series circuit of a second inductor 6 'and a second control winding N4 of a transformer 7 is provided and connected to one end of a second smoothing capacitor 8'. And a second switch element 14 that is turned on when the voltage of the AC power supply is lower than the common point of 8 'and 8', to constitute a voltage doubler input circuit.
[0009]
When the voltage of the AC power supply 1 is low, the second switch element 14 is turned on.
Thus, in the positive half cycle, AC power supply 1 → diode 2 → inductor 6 → control winding N3 → smoothing capacitor 8 → second switch element 14 → diode 5 → route of AC power supply 1 In the negative half cycle, the AC power supply 1 → the second switch element 14 → the second smoothing capacitor 8 ′ → the second control winding N4 → the second inductor 6 ′ → the diode 4 → Current flows at the root of the AC power supply 1.
[0010]
As a result, the smoothing capacitors 8 and 8 'are each charged with the peak value of the AC input voltage, so that an input voltage twice as high as that obtained by full-wave rectification can be obtained.
[0011]
When the voltage of the AC power supply 1 is high, the second switch element 14 is turned off to provide a simple full-wave rectifier circuit.
[0012]
The operations of the inductor and the control winding relating to the power factor improvement are substantially the same as those in FIG.
[0013]
[Problems to be solved by the invention]
The prior art described so far is a very effective circuit in that power factor improvement and high efficiency can be realized only by providing a series circuit of an inductor and a transformer control winding in an input-side rectifier circuit.
[0014]
However, if the AC input voltage rises rapidly within, for example, an allowable fluctuation range, the control windings of the inductor and the transformer provided for improving the power factor adversely affect the operation. That is, the sudden change in the input voltage causes a potential difference between the voltage (point A) after the input rectification shown in FIG. 1 and the voltage (point B) of the smoothing capacitor 8, and the series impedance of the inductor 6 and the control winding N3 of the transformer. -Excessive current divided by dance flows.
[0015]
This current is induced from the control winding N3 of the transformer 7 to the primary winding N1 according to the turn ratio, and as a result, an excessive current flows through the switch element 9, which may damage the element.
[0016]
Further, when a current detection circuit is provided in series with the switch element 9, the current is detected as an overcurrent and becomes a drooping state in spite of the normal operation state, and there is a possibility that the output voltage is greatly reduced. .
These factors also cause a reduction in the reliability of the power supply system.
[0017]
Therefore, the present invention solves such a drawback by suppressing an excessive current from flowing to the input side circuit in response to a sudden rise in the input voltage, and a technique for preventing the destruction of the switch element and the decrease in the output voltage. It is a suggestion.
[0018]
The case of the voltage doubler circuit of FIG. 2 also has exactly the same problems as described above.
[0019]
[Means for Solving the Problems]
Therefore, according to the present invention, a diode is provided in parallel with the series circuit of the inductor and the transformer control winding provided for improving the power factor, and a difference voltage which is likely to be generated when the input voltage rises sharply is clamped to the input smoothing capacitor voltage. This is a switching power supply characterized by having a circuit configuration for causing the switching power supply.
[0020]
【Example】
FIG. 3 shows an embodiment of a switching power supply in which the technology of the present invention is applied to the conventional technology of FIG.
1 have the same names as in FIG.
In FIG. 3, a diode 14 is provided in parallel with a series circuit of an inductor 6 and a control winding N3 of a transformer 7 in a charging direction of a smoothing capacitor 8N.
[0021]
As a result, when the voltage of the AC power supply 1 rises rapidly within the input voltage fluctuation range, a potential difference occurs between the voltage after the input rectification (point A) and the voltage of the smoothing capacitor 8 (point B). By short-circuiting between the voltage (point A) after input rectification and the voltage (point B) of the smoothing capacitor 8 by the diode 14, the potential difference to be generated is quickly reduced.
[0022]
As a result, the current removed by the series impedance of the inductor 6 and the control winding N3 becomes almost zero, and the current induced from the control winding N3 to the primary winding N1 according to the turn ratio becomes zero. .
As a result, an excessive current does not flow through the switch element 9, and there is no problem such as damage to the switch element 9 or a decrease in output voltage due to overcurrent detection.
[0023]
FIG. 4 shows another embodiment of the switching power supply in which the technology of the present invention is applied to the conventional technology of FIG. The same reference numerals as those in FIG. 1 denote the same names. Charging routes from both poles of the AC power supply 1 to the smoothing capacitor 8 through the diodes 15 and 16 are provided. So that no potential difference occurs.
The description of the operation is substantially the same as that of FIG.
[0024]
FIG. 5 shows a first embodiment in which the technique of the present invention is applied to the double voltage input switching power supply of FIG. 2 have the same names as in FIG.
[0025]
A diode 17 is provided in parallel with the series circuit of the inductor 6 and the control winding N3 in a direction for charging the smoothing capacitor 8, and is connected in parallel with the series circuit of the second inductor 6 'and the second control winding N'. In addition, a diode 18 is provided in a direction for discharging the second smoothing capacitor 8 '.
The principle of short-circuiting the potential difference between the inductor and the control winding due to the diode when the input voltage sharply rises is the same as that described above, and a description thereof will be omitted.
[0026]
FIG. 6 shows another embodiment of the present invention in the switching power supply of the double voltage input of FIG. Also in this case, the same reference numerals as those in FIG. 2 are omitted, but in the present invention, a charging route to the smoothing capacitor 8 is provided from both poles of the AC input 1 through the diodes 19 and 20, and a smoothing capacitor 8 'is provided. Are provided to return the discharge route of the AC power source 1 to both poles of the AC power supply 1 through diodes 21 and 22. This prevents a potential difference between the inductor 6 and the control winding N3, the second inductor 6 'and the second control winding N4 when the input voltage rises sharply.
[0027]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, when an input voltage rises sharply, since a switch element is not damaged and a fall of an output voltage can be suppressed, a highly reliable power factor improvement type switching power supply can be provided. is there.
[Brief description of the drawings]
FIG. 1 is an example of a conventional power factor improving switching power supply. FIG. 2 is an example of a conventional power factor improving switching power supply using a voltage doubler rectifier circuit. FIG. 3 is a conventional switching power supply of FIG. FIG. 4 shows another embodiment of a switching power supply in which the present invention is applied to the conventional switching power supply of FIG. 1. FIG. 5 shows a double voltage input type switching of FIG. Embodiment of a switching power supply in which the present invention is applied to a power supply [FIG. 6] Another embodiment of a switching power supply in which the present invention is applied to a double voltage input type switching power supply of FIG.
1 AC power supply 2-5 Full-wave rectifier 6 Inductor 6 'Second inductor 7 Transformer 8 Smoothing capacitor 8' Second smoothing capacitor 9 Switch element 10, 11 Diode 12 Reactor 13 Capacitor 14 Second switch element 15- 22 Diode N1 Primary winding of transformer 7 N2 Secondary winding of transformer 7 Control winding of transformer 7 N4 Second control winding of transformer 7

Claims

A smoothing capacitor is connected between output terminals of a full-wave rectifier connected to an AC power supply, a primary winding of a transformer and a series circuit of a switch element are connected between terminals of the smoothing capacitor, and a secondary winding of the transformer is connected. In a switching power supply for supplying power to a load connected between output terminals of the rectifying / smoothing circuit, controlling an inductor and the transformer between the full-wave rectifier and the smoothing capacitor. A switching power supply , wherein a winding is connected in series, and a diode having a polarity for charging the smoothing capacitor is connected in parallel with a series circuit of the inductor and the control winding of the transformer.

A smoothing capacitor is connected between output terminals of a full-wave rectifier connected to an AC power supply, a primary winding of a transformer and a series circuit of a switch element are connected between terminals of the smoothing capacitor, and a secondary winding of the transformer is connected. In a switching power supply for supplying power to a load connected between output terminals of the rectifying / smoothing circuit, controlling an inductor and the transformer between the full-wave rectifier and the smoothing capacitor. connect the windings in series, each from both poles of the AC power supply, between the connection portion between the smoothing capacitor and the transformer of the control winding, diode polarity to charge the smoothing capacitor - that connects the de A switching power supply.

A smoothing capacitor is connected between output terminals of a full-wave rectifier connected to an AC power supply, a primary winding of a transformer and a series circuit of a switch element are connected between terminals of the smoothing capacitor, and a secondary winding of the transformer is connected. In a switching power supply for supplying power to a load connected between output terminals of the rectifying and smoothing circuit, an inductor is provided between an output terminal of the full-wave rectifier and each terminal of the smoothing capacitor. And a series circuit of control windings of the transformer, and the smoothing capacitor is configured by connecting a first and a second smoothing capacitor in series, and a connection point between the first smoothing capacitor and the second smoothing capacitor. A switch element is interposed between the AC power supply and one end of the AC power supply, and the switch element is turned on during a period in which the output voltage of the AC power supply is low. And configured to turn off the high period, in parallel to the series circuit of the control winding of the said inductor transformer, diode polarity to charge the smoothing capacitor - switching power supply, characterized in that connecting the de .

A smoothing capacitor is connected between output terminals of a full-wave rectifier connected to an AC power supply, a primary winding of a transformer and a series circuit of a switch element are connected between terminals of the smoothing capacitor, and a secondary winding of the transformer is connected. In a switching power supply for supplying power to a load connected between output terminals of the rectifying and smoothing circuit, an inductor is provided between an output terminal of the full-wave rectifier and each terminal of the smoothing capacitor. And a series circuit of control windings of the transformer, and the smoothing capacitor is configured by connecting a first and a second smoothing capacitor in series, and a connection point between the first smoothing capacitor and the second smoothing capacitor. A switch element is interposed between the AC power supply and one end of the AC power supply, and the switch element is turned on during a period in which the output voltage of the AC power supply is low. And configured to turn off the high period, each from both poles of the AC power source, respectively between a connection portion between the smoothing capacitor and the transformer of the control winding, the polarity of charging the smoothing capacitor diode - de A switching power supply characterized by being connected to.