JP2019187073A

JP2019187073A - DC power supply

Info

Publication number: JP2019187073A
Application number: JP2018075143A
Authority: JP
Inventors: 晴之宮崎; Haruyuki Miyazaki; 京極　章弘; Akihiro Kyogoku; 章弘京極
Original assignee: Panasonic Intellectual Property Management Co Ltd
Current assignee: Panasonic Intellectual Property Management Co Ltd
Priority date: 2018-04-10
Filing date: 2018-04-10
Publication date: 2019-10-24

Abstract

【課題】力率改善を行わない場合にも、交流電源からの交流電流が逆向きに流れることなく、安定した同期整流を実現し、直流電源装置の変換効率を向上する。【解決手段】同期整流動作とともに交流電源の力率改善を行う第一の動作モード及び、同期整流のみを実施し、力率改善を行わない第二の動作モードで動作する直流電源装置において、正と負の閾値を予め記憶させておく閾値記憶部とを備え、前記交流電源からの交流電圧の極性が正の場合に、交流電流が前記閾値記憶部で記憶した正の閾値未満の時には、少なくとも前記フルブリッジ回路４のローサイド開放することで同期整流を部分的に禁止し、前記交流電源からの交流電圧の極性が負の場合に、交流電流が前記閾値記憶部で記憶した負の閾値超過の時には、少なくとも前記フルブリッジ回路４のハイサイドを開放することで同期整流を部分的に禁止する。【選択図】図１An object of the present invention is to realize a stable synchronous rectification without an AC current from an AC power supply flowing in a reverse direction even when a power factor is not improved, and to improve a conversion efficiency of a DC power supply device. In a DC power supply device operating in a first operation mode for improving the power factor of an AC power supply together with a synchronous rectification operation and in a second operation mode for performing only synchronous rectification and not performing a power factor improvement, And a threshold storage unit that stores a negative threshold in advance, when the polarity of the AC voltage from the AC power supply is positive, when the AC current is less than the positive threshold stored in the threshold storage unit, at least Opening the low side of the full bridge circuit 4 partially inhibits synchronous rectification, and when the polarity of the AC voltage from the AC power supply is negative, the AC current exceeds the negative threshold value stored in the threshold storage unit. In some cases, synchronous rectification is partially prohibited by opening at least the high side of the full bridge circuit 4. [Selection diagram] Fig. 1

Description

本発明は、力率改善機能を有した直流電源装置に関するものである。 The present invention relates to a DC power supply device having a power factor correction function.

ＭＯＳＦＥＴを用いて同期整流を行うフルブリッジ構成の直流電源装置において、交流電圧が低く、交流電流が流れていないタイミングでＭＯＳＦＥＴがオン状態になると、交流電流が逆向きに流れる期間ができ、歪みなど交流電流波形に影響を及ぼし、直流電源装置の変換効率が低下する。
そこで、交流電流の指令値あるいは検出値の絶対値と所定の閾値との比較結果にもとづき、同期整流を実施あるいは禁止する方法がある（例えば、特許文献１参照。） In a DC power supply with a full bridge configuration that performs synchronous rectification using a MOSFET, when the MOSFET is turned on at a timing when the AC voltage is low and no AC current is flowing, there is a period in which the AC current flows in the reverse direction, distortion, etc. This affects the AC current waveform and reduces the conversion efficiency of the DC power supply.
Therefore, there is a method of performing or prohibiting synchronous rectification based on a comparison result between an AC current command value or an absolute value of a detection value and a predetermined threshold (see, for example, Patent Document 1).

特開２０１５−１３９３０１号公報JP2015-139301A

しかしながら、交流電流指令値の絶対値と閾値との比較結果にもとづき、同期整流の実施あるいは禁止を判断すると、交流電源の力率改善を行わない場合には、交流電流の指令値がゼロとなるため、同期整流が常時禁止され直流電源装置の変換効率を向上することができない。同様に、交流電流検出値の絶対値を用いて同期整流を実施あるいは禁止を判断する場合にも、交流電流が逆流しているか否かを判断することができない。
本発明は上記課題を解決するもので、力率改善を行わない場合にも、交流電源からの交流電流が逆向きに流れることなく、安定した同期整流を実現し、直流電源装置の変換効率を向上することを目的とする。 However, based on the comparison result between the absolute value of the alternating current command value and the threshold value, if it is determined whether to perform synchronous rectification or not, the alternating current command value becomes zero when the power factor of the alternating current power supply is not improved. Therefore, synchronous rectification is always prohibited and the conversion efficiency of the DC power supply cannot be improved. Similarly, even when performing synchronous rectification or determining prohibition using the absolute value of the AC current detection value, it cannot be determined whether the AC current is flowing backward.
The present invention solves the above-described problem. Even when the power factor is not improved, the AC current from the AC power source does not flow in the reverse direction, and stable synchronous rectification is realized, thereby improving the conversion efficiency of the DC power source device. The purpose is to improve.

前記従来技術の課題を解決するために本発明の直流電源装置では、ＭＯＳＦＥＴあるいはＧａＮトランジスタを用いたフルブリッジ回路と、リアクタと、平滑コンデンサと、交流電流検出手段と、交流電圧位相検出手段と、交流電圧極性判断部と、閾値記憶部とを含み、前記交流電流検出手段にて検出した交流電流と前記閾値記憶部にて予め設けた閾値との比較結果にもとづき同期整流を実施あるいは禁止する。
さらに、前記閾値記憶部において、前記交流電源の力率改善を行わない場合に対し、前記交流電源の力率改善を行う場合の閾値の絶対値が大きくなるように設定する。
あるいは、前記閾値記憶部において、同期整流を実施する閾値と同期整流を禁止する閾値とを設け、同期整流を実施する閾値あるいは同期整流を禁止する閾値の少なくとも一方を、前記リアクタの値や前記交流電源からの交流電流の大きさあるいは前記交流電源の力率改善を行っているか否かに応じて変更する。 In order to solve the problems of the prior art, in the DC power supply device of the present invention, a full bridge circuit using a MOSFET or a GaN transistor, a reactor, a smoothing capacitor, an AC current detection means, an AC voltage phase detection means, An AC voltage polarity determination unit and a threshold value storage unit are included, and synchronous rectification is performed or prohibited based on a comparison result between the AC current detected by the AC current detection means and a threshold value provided in advance in the threshold value storage unit.
Further, the threshold value storage unit is set so that the absolute value of the threshold value when the power factor of the AC power source is improved is larger than when the power factor of the AC power source is not improved.
Alternatively, in the threshold value storage unit, a threshold value for performing synchronous rectification and a threshold value for prohibiting synchronous rectification are provided, and at least one of a threshold value for performing synchronous rectification or a threshold value for prohibiting synchronous rectification is set as the value of the reactor or the alternating current. It changes depending on the magnitude of the alternating current from the power supply or whether the power factor of the alternating current power supply is being improved.

本発明の直流電源装置は、力率改善を行わない場合にも交流電源からの交流電流が逆向きに流れることなく、安定した同期整流を実現し、直流電源装置の変換効率を向上できる。 The direct current power supply device of the present invention can realize stable synchronous rectification without increasing the alternating current from the alternating current power supply in the reverse direction even when the power factor is not improved, and can improve the conversion efficiency of the direct current power supply device.

本発明の実施の形態１における力率改善装置の構成を示す図The figure which shows the structure of the power factor improvement apparatus in Embodiment 1 of this invention. 本発明の実施の形態１における、第一及び第二のモードで動作した場合のフルブリッジ回路のスイッチングパターンを示す図The figure which shows the switching pattern of a full bridge circuit at the time of operate | moving in the 1st and 2nd mode in Embodiment 1 of this invention. 本発明の実施の形態１における、第一の動作モードでの同期整流判定部９ｄ及びフルブリッジ回路４の動作に関する概要を示す図The figure which shows the outline | summary regarding operation | movement of the synchronous rectification determination part 9d and the full bridge circuit 4 in 1st operation mode in Embodiment 1 of this invention. 本発明の実施の形態１における、第二の動作モードでの同期整流判定部９ｄ及びフルブリッジ回路４の動作に関する概要を示す図The figure which shows the outline | summary regarding operation | movement of the synchronous rectification determination part 9d and the full bridge circuit 4 in 2nd operation mode in Embodiment 1 of this invention. 本発明の実施の形態２における力率改善装置の構成を示す図The figure which shows the structure of the power factor improvement apparatus in Embodiment 2 of this invention.

第１の発明は、ＭＯＳＦＥＴあるいはＧａＮトランジスタがそれぞれ直列に接続された第一及び第二の直列回路が並列に接続されたフルブリッジ回路と、前記フルブリッジ回路と交流電源との間に設けられたリアクタと、前記フルブリッジ回路の出力側に並列接続された平滑コンデンサと、前記交流電源からの交流電流を検出する交流電流検出手段と、前記交流電源からの交流電圧の位相を検出する交流電圧位相検出手段と、前記交流電圧位相検出手段からの情報にもとづき交流電圧の極性を判断する交流電圧極性判断部とを有し、前記交流電源からの交流電圧の極性が正であれば、前記第一の直列回路のローサイドを短絡及び開放して、前記交流電源からの交流電流が略正弦波となるように力率改善を行うとともに、前記第一の直列回路のローサイドを開放している期間のみ前記第一の直列回路のハイサイドを短絡することに加え、前記第二の直列回路のローサイドを短絡し、前記第二の直列回路のハイサイドを開放することで同期整流を実施し、前記交流電源からの交流電圧の極性が負であれば、前記第一の直列回路のハイサイドを短絡及び開放して、前記交流電源からの交流電流が略正弦波となるように力率改善を行うとともに、前記第一の直列回路のハイサイドを開放している期間のみ前記第一の直列回路のローサイドを短絡することに加え、前記第二の直列回路のハイサイドを短絡し、前記第二の直列回路のローサイドを開放することで同期整流を実施する第一の動作モードと、前記交流電源からの交流電圧の極性が正であれば、前記第一の直列回路のハイサイド及び前記第二の直列回路のローサイドを短絡し、前記第一の直列回路のローサイド及び前記第二の直列回路のハイサイドを開放することで同期整流を実施し、前記交流電源からの交流電圧の極性が負であれば、前記第一の直列回路のローサイド及び前記第二の直列回路のハイサイドを短絡し、前記第一の直列回路のハイサイド及び前記第二の直列回路のローサイドを開放することで同期整流を実施する第二の動作モードとを有し、前記第一の動作モードと第二の動作モードのいずれかで動作する直流電源装置であって、正と負の閾値を予め記憶させておく閾値記憶部とを備え、前記交流電源からの交流電圧の極性が正の場合に、交流電流が前記閾値記憶部で記憶した正の閾値未満の時には、少なくとも前記第二の直列回路のローサイドを開放することで同期整流を部分的に禁止し、前記交流電源からの交流電圧の極性が負の場合に、交流電流が前記閾値記憶部で記憶した負の閾値超過の時には、少なくとも第二の直列回路のハイサイドを開放することで同期整流を部分的に禁止することを特徴とする直流電源装置である。
これにより、力率改善を行わない場合にも、交流電源からの交流電流が逆向きに流れることなく、安定した同期整流を実現し、直流電源装置の変換効率を向上できる。
第２の発明は、第１の発明において、第二の動作モードよりも、第一の動作モードの正と負の両閾値の絶対値が大きくなるようにしたものである。
第３の発明は、第１の発明あるいは第２の発明において、同期整流を実施する閾値と同期整流を禁止する閾値とを設けたものである。
これにより、交流電源からの交流電流のリプル等の影響により、閾値近傍で同期整流の実施と禁止とが頻繁に発生することを回避し、より一層直流電源装置を安定に動作できる。第４の発明は、第３の発明において、同期整流を実施する閾値あるいは同期整流を禁止する閾値の少なくとも一方を、前記リアクタの値や前記電流検出手段にて検出した交流電流の大きさあるいは前記交流電源の力率改善を行っているか否かに応じて変更するものである。
これにより、交流電源からの交流電流のリプルの大きさに寄与するリアクタの値や交流電
流の大きさあるいは力率改善を行っているか否かに応じて、同期整流を許可する閾値と同期整流を禁止する閾値との差を必要最小限に設定できるため、交流電源からの交流電流のリプル等の影響により、閾値近傍で同期整流の実施と禁止とが頻繁に発生することを回避しつつ、同期整流による直流電源装置の効率を最大限向上できる。
以下、本発明の実施の形態について、図面を参照しながら説明する。尚、この実施の形態によって本発明が限定されるものではない。
（実施の形態１）
図１は、本発明の第１の実施の形態における直流電源装置の構成を示す図である。
図１に示すように、本実施の形態における直流電源装置は、交流電源１の一方の交流ラインに接続されたリアクタ３と、交流電源１の一端に接続され交流電源１から流れる電流を検出する交流電流検出手段２と、ＭＯＳＦＥＴあるいはＧａＮトランジスタがそれぞれ直列に接続された第一及び第二の直列回路が並列に接続されたフルブリッジ回路４と、フルブリッジ回路４の出力側に並列接続された平滑コンデンサ５と、フルブリッジ回路４の出力側の直流電圧を検出する平滑コンデンサ５に並列接続された直流電圧検出手段６を具備する。
本実施の形態の直流電源装置は、マイクロコンピュータなどから構成される制御部９と、交流電源１の両端に接続された交流電圧位相検出手段８（例えばゼロクロス検出回路など）を備えており、制御部９は交流電圧位相検出手段８から得られる交流電源１からの交流電圧のゼロクロス点と交流電圧の周期から、交流電源１からの交流電圧の位相を推定演算する交流電圧位相演算部９ａと、交流電圧位相検出手段８において交流電圧とゼロクロス基準電圧とを比較することで交流電圧の極性を判断する交流電圧極性判定部９ｇと、直流電圧検出手段６の検出値と直流電圧指令値との比較結果に応じて比例積分補償演算を行う電圧制御部９ｆと、電圧位相演算部９ａから得られる交流電圧の位相に相当する略正弦波状の基準電流波形の電流振幅値と電圧制御部９ｆの出力とを乗算することで電流指令を生成し、交流電流検出手段２で検出した交流電流検出値と等しくなるように比例積分補償演算する電流制御部９ｂと、電流制御部９ｂの出力と三角波状の搬送波を比較しフルブリッジ回路４のＰＷＭ駆動信号を生成するＰＷＭ信号生成部９ｃと、正と負の閾値を予め記憶する閾値記憶部９ｅと、交流電圧極性判定部９ｇからの情報にもとづき、交流電圧の極性ごとに交流電流検出手段２から検出した電流値と閾値記憶部１０ｅで記憶した正負の閾値との大小関係に応じて、フルブリッジ回路４の同期整流を実施あるいは禁止を判定する同期整流実施・禁止判定部９ｄを有し、フルブリッジ回路４を短絡及び開放させることで直流電圧が直流電圧指令と等しくなるように制御し、直流電圧を負荷７へ供給する。
以下に、同期整流判定部９ｄと閾値記憶部９ｅの詳細について説明する。
まず、閾値記憶部９ｅでは正と負の閾値を各々設けることに加え、交流電流のリプルなどの影響により、閾値近傍で同期整流の実施と禁止が頻繁に発生することを回避し、より一層安定に同期整流を実施するために、第二の動作モードよりも電流リプルが大きくなる第一の動作モードの方が、正負の両閾値の絶対値が大きくなるようにする。
次に、同期整流判定部９ｄについて、図２〜図４を用いて説明する。
第一の動作モードでは、図２のように交流電圧極性判定部９ｇにおいて交流電圧の極性が正であると判定した場合、交流電流検出手段２で検出した電流値が閾値記憶部９ｅで記憶した正の閾値以上であれば、フルブリッジ回路４の第二の直列回路のハイサイド４ｃを開放し、フルブリッジ回路４の第二の直列回路のローサイド４ｄを短絡することに加え、フルブリッジ回路４の第一の直列回路のローサイド４ｂはＰＷＭ信号生成部９ｃで生成されたＰＷＭ信号を出力するとともに、フルブリッジ回路４の第一の直列回路のハイサイド４ａはＰＷＭ信号生成部９ｃで生成されたＰＷＭ信号に対し相補のＰＷＭ信号、あるいはＰＷＭ信号に対し相補のＰＷＭ信号から所定のデッドタイムを考慮したＰＷＭ信号を出力することで、交流電源の力率改善を行うとともに、同期整流を実施する。一方、交流電流検出手段２で検出した電流値が閾値記憶部９ｅで記憶した正の閾値未満であれば、フルブリッジ回路４の第一の直列回路のローサイド４ｂはＰＷＭ信号生成部９ｃで生成されたＰＷＭ信号を出力するとともに、少なくとも前記フルブリッジ回路４のローサイド４ｄを開放
し、同期整流を部分的に禁止することで、図３のように少なくとも前記フルブリッジ回路４のローサイド４ｄがダイオードの状態となるため、交流電源の力率改善を行いながら、前記交流電源からの交流電流が逆向きに流れることを防止できる。
また、図２のように交流電圧極性判定部９ｇにおいて交流電圧の極性が負であると判定した場合、交流電流検出手段２で検出した電流値が閾値記憶部９ｅで記憶した負の閾値以下であれば、フルブリッジ回路４の第二の直列回路のローサイド４ｄを開放し、フルブリッジ回路４の第二の直列回路のハイサイド４ｃを短絡することに加え、フルブリッジ回路４の第一の直列回路のハイサイド４ａはＰＷＭ信号生成部９ｃで生成されたＰＷＭ信号を出力するとともに、フルブリッジ回路４の第一の直列回路のローサイド４ｂはＰＷＭ信号生成部９ｃで生成されたＰＷＭ信号に対し相補のＰＷＭ信号、あるいはＰＷＭ信号に対し相補のＰＷＭ信号から所定のデッドタイムを考慮したＰＷＭ信号を出力することで、交流電源の力率改善を行うとともに、同期整流を実施する。一方、交流電流検出手段２で検出した電流値が閾値記憶部９ｅで記憶した負の閾値超過であれば、フルブリッジ回路４の第一の直列回路のハイサイド４ａはＰＷＭ信号生成部９ｃで生成されたＰＷＭ信号を出力するとともに、少なくともフルブリッジ回路４のハイサイド４ｃを開放し、同期整流を部分的に禁止することで、図３のように少なくとも前記フルブリッジ回路４のハイサイド４ｃがダイオードの状態となるため、交流電源の力率改善を行いながら、前記交流電源からの交流電流が逆向きに流れることを防止できる。
第二の動作モードでは、図２のように交流電圧極性判定部９ｇにおいて交流電圧の極性が正であると判定した場合、交流電流検出手段２で検出した電流値が閾値記憶部９ｅで記憶した正の閾値以上であれば、フルブリッジ回路４の第一の直列回路のハイサイド４ａ及びフルブリッジ回路４の第二の直列回路のローサイド４ｄを短絡するとともに、フルブリッジ回路４の第一の直列回路のローサイド４ｂ及びフルブリッジ回路４の第二の直列回路のハイサイド４ｃを開放することで同期整流を実施する。一方、交流電流検出手段２で検出した電流値が閾値記憶部９ｅで記憶した正の閾値未満であれば、フルブリッジ回路４の第一の直列回路のローサイド４ｂ及びフルブリッジ回路４の第二の直列回路のハイサイド４ｃに加え、フルブリッジ回路４の第一の直列回路のハイサイド４ａあるいはフルブリッジ回路４の第二の直列回路のローサイド４ｄの少なくとも一方を開放し、同期整流を部分的に禁止することで、図４のようにフルブリッジ回路４の第一の直列回路のハイサイド４ａあるいはフルブリッジ回路４の第二の直列回路のローサイド４ｄの少なくとも一方がダイオードの状態となるため、前記交流電源からの交流電流が逆向きに流れることを防止できる。
また、図２のように交流電圧極性判定部９ｇにおいて交流電圧の極性が負であると判定した場合、交流電流検出手段２で検出した電流値が閾値記憶部９ｅで記憶した負の閾値以下であれば、フルブリッジ回路４の第一の直列回路のローサイド４ｂ及びフルブリッジ回路４の第二の直列回路のハイサイド４ｃを短絡するとともに、フルブリッジ回路４の第一の直列回路のハイサイド４ａ及びフルブリッジ回路４の第二の直列回路のローサイド４ｄを開放することで同期整流を実施する。一方、交流電流検出手段２で検出した電流値が閾値記憶部９ｅで記憶した負の閾値超過であれば、フルブリッジ回路４の第一の直列回路のハイサイド４ａ及びフルブリッジ回路４の第二の直列回路のローサイド４ｄに加え、フルブリッジ回路４の第一の直列回路のローサイド４ｂあるいはフルブリッジ回路４の第二の直列回路のハイサイド４ｃの少なくとも一方を開放し、同期整流を部分的に禁止することで、図４のようにフルブリッジ回路４の第一の直列回路のローサイド４ｂあるいはフルブリッジ回路４の第二の直列回路のハイサイド４ｃの少なくとも一方がダイオードの状態となるため、前記交流電源からの交流電流が逆向きに流れることを防止できる。
本発明では、検出した交流電流と予め設けた閾値との大小関係に応じて、ＭＯＳＦＥＴあるいはＧａＮトランジスタがそれぞれ直列に接続された第一及び第二の直列回路が並列に接続されたフルブリッジ回路の同期整流を実施あるいは禁止することで、力率改善を行わない場合にも、交流電源からの交流電流が逆向きに流れることなく、安定した同期整流を実現し、直流電源装置の変換効率を向上できる。
（実施の形態２）
図５は、本発明の第２の実施の形態における直流電源装置の構成を示す図である。
尚、本発明の第２の実施の形態における力率改善装置は、実施の形態１と同じ回路構成であるため、実施の形態１と差異のある閾値記憶部９ｅの動作についてのみ説明する。
閾値記憶部９ｅでは、交流電流のリプルなどの影響により、閾値近傍で同期整流の実施と禁止が頻繁に発生することを回避し、より一層安定に同期整流を実施するために、交流電流検出手段２から検出した電流値との比較により同期整流を実施する閾値及び同期整流を禁止する閾値を各々設け、同期整流を実施する閾値の絶対値が同期整流を禁止する閾値の絶対値よりも大きくなるように設定する。尚、同期整流を許可する閾値と同期整流を禁止する閾値との差が過度に大きくなると同期整流による、直流電源装置の変換効率向上効果が低下してしまうため、交流電流のリプル幅に応じて、同期整流を許可する閾値と同期整流を禁止する閾値との差を変更する。例えば、電流リプルの大きさは、リアクタ３や交流電流検出手段２で検出した交流入力電流の大きさあるいは交流電源の力率改善を行っているか否かにによって異なる為、それらの関係を予め記憶したマップを設け、リアクタ３や交流電流検出手段２あるいは交流電圧位相検出手段８で検出した交流入力電流の大きさあるいは交流電源の力率改善を行っているか否かにもとづき、予め記憶したマップから電流リプルの大きさを判断し、電流リプルの大きさに応じて同期整流を実施する閾値あるいは同期整流を禁止する閾値の少なくとも一方を変更する。
本発明では、検出した交流電流と予め設けた閾値との大小関係に応じて、ＭＯＳＦＥＴあるいはＧａＮトランジスタがそれぞれ直列に接続された第一及び第二の直列回路が並列に接続されたフルブリッジ回路の同期整流を実施あるいは禁止することで、力率改善を行わない場合にも、交流電源からの交流電流が逆向きに流れることなく、安定した同期整流を実現し、直流電源装置の変換効率を向上できる。 A first invention is provided between a full bridge circuit in which a first and second series circuit each having a MOSFET or a GaN transistor connected in series are connected in parallel, and the full bridge circuit and an AC power supply. A reactor, a smoothing capacitor connected in parallel to the output side of the full bridge circuit, AC current detection means for detecting an AC current from the AC power supply, and an AC voltage phase for detecting the phase of the AC voltage from the AC power supply An AC voltage polarity determination unit that determines the polarity of the AC voltage based on information from the AC voltage phase detection unit, and the first voltage is positive if the polarity of the AC voltage from the AC power supply is positive. The low side of the series circuit is short-circuited and opened, and the power factor is improved so that the alternating current from the alternating-current power supply becomes a substantially sine wave, and the first series circuit In addition to shorting the high side of the first series circuit only during the period when the side is open, shorting the low side of the second series circuit and opening the high side of the second series circuit If synchronous rectification is performed and the polarity of the AC voltage from the AC power source is negative, the high side of the first series circuit is short-circuited and opened, and the AC current from the AC power source becomes a substantially sine wave. In addition to short-circuiting the low side of the first series circuit only during the period when the high side of the first series circuit is opened, the high side of the second series circuit is If the first operation mode for performing the synchronous rectification by short-circuiting and opening the low side of the second series circuit and the polarity of the AC voltage from the AC power supply is positive, the first series circuit High side and front Synchronous rectification is performed by short-circuiting the low side of the second series circuit and opening the low side of the first series circuit and the high side of the second series circuit, and the polarity of the AC voltage from the AC power source is If negative, short-circuit the low side of the first series circuit and the high side of the second series circuit, and open the high side of the first series circuit and the low side of the second series circuit. A DC power supply device having a second operation mode for performing synchronous rectification and operating in either the first operation mode or the second operation mode, wherein positive and negative threshold values are stored in advance. A threshold storage unit, and when the polarity of the AC voltage from the AC power source is positive, when the alternating current is less than the positive threshold stored in the threshold storage unit, at least the low side of the second series circuit is To open If the polarity of the AC voltage from the AC power source is negative and the AC current exceeds the negative threshold stored in the threshold storage unit, at least the second series circuit is at a high level. The DC power supply device is characterized in that synchronous rectification is partially prohibited by opening a side.
As a result, even when the power factor is not improved, stable synchronous rectification is realized without the alternating current from the alternating current flowing in the reverse direction, and the conversion efficiency of the direct current power supply device can be improved.
According to a second aspect, in the first aspect, the absolute values of both positive and negative thresholds in the first operation mode are larger than those in the second operation mode.
According to a third invention, in the first invention or the second invention, a threshold value for executing synchronous rectification and a threshold value for prohibiting synchronous rectification are provided.
As a result, it is possible to avoid the frequent occurrence and prohibition of synchronous rectification near the threshold due to the influence of ripples of alternating current from the alternating current power supply, and to operate the direct current power supply more stably. In a fourth aspect based on the third aspect, at least one of a threshold value for performing synchronous rectification and a threshold value for prohibiting synchronous rectification is set to a value of the reactor, a magnitude of an alternating current detected by the current detection means, or the It is changed according to whether or not the power factor of the AC power source is improved.
Thus, depending on the value of the reactor that contributes to the magnitude of the AC current ripple from the AC power supply, the magnitude of the AC current, or whether the power factor is being improved, the threshold value that allows synchronous rectification and the synchronous rectification Since the difference from the prohibited threshold can be set to the minimum necessary, synchronous rectification is frequently performed and prohibited in the vicinity of the threshold due to the influence of ripples of alternating current from the alternating current power supply. The efficiency of the DC power supply by rectification can be improved to the maximum.
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiment.
(Embodiment 1)
FIG. 1 is a diagram showing a configuration of a DC power supply device according to the first embodiment of the present invention.
As shown in FIG. 1, the DC power supply in the present embodiment detects a reactor 3 connected to one AC line of an AC power supply 1 and a current flowing from the AC power supply 1 connected to one end of the AC power supply 1. The full-bridge circuit 4 in which the alternating current detection means 2 and the first and second series circuits each having a MOSFET or GaN transistor connected in series are connected in parallel and the output side of the full-bridge circuit 4 are connected in parallel A smoothing capacitor 5 and DC voltage detecting means 6 connected in parallel to the smoothing capacitor 5 for detecting the DC voltage on the output side of the full bridge circuit 4 are provided.
The DC power supply device according to the present embodiment includes a control unit 9 constituted by a microcomputer and the like, and AC voltage phase detection means 8 (for example, a zero cross detection circuit) connected to both ends of the AC power supply 1 for control. The unit 9 is an AC voltage phase calculation unit 9a that estimates and calculates the phase of the AC voltage from the AC power source 1 from the zero cross point of the AC voltage from the AC power source 1 obtained from the AC voltage phase detection means 8 and the cycle of the AC voltage. The AC voltage phase detection means 8 compares the AC voltage with the zero-cross reference voltage to determine the polarity of the AC voltage, and compares the detected value of the DC voltage detection means 6 with the DC voltage command value. A voltage control unit 9f that performs proportional integral compensation calculation according to the result, and a current amplitude of a substantially sinusoidal reference current waveform corresponding to the phase of the AC voltage obtained from the voltage phase calculation unit 9a Current control unit 9b that generates a current command by multiplying the voltage control unit 9f by the output of the voltage control unit 9f and performs proportional-integral compensation calculation so as to be equal to the AC current detection value detected by the AC current detection means 2, and a current control unit A PWM signal generation unit 9c that compares the output of 9b with a triangular wave carrier wave to generate a PWM drive signal of the full bridge circuit 4, a threshold storage unit 9e that stores positive and negative threshold values in advance, and an AC voltage polarity determination unit 9g Based on the information from, the full bridge circuit 4 is synchronously rectified according to the magnitude relationship between the current value detected from the AC current detection means 2 and the positive / negative threshold value stored in the threshold value storage unit 10e for each polarity of the AC voltage. Alternatively, it includes a synchronous rectification execution / prohibition determination unit 9d that determines prohibition, and controls the DC voltage to be equal to the DC voltage command by short-circuiting and opening the full bridge circuit 4 to The supply to the load 7.
Details of the synchronous rectification determination unit 9d and the threshold storage unit 9e will be described below.
First, in the threshold storage unit 9e, in addition to providing positive and negative thresholds, it is possible to avoid the frequent occurrence and prohibition of synchronous rectification near the threshold due to the influence of AC current ripple, etc. In order to implement synchronous rectification, the absolute value of both positive and negative threshold values is made larger in the first operation mode in which the current ripple is larger than in the second operation mode.
Next, the synchronous rectification determination unit 9d will be described with reference to FIGS.
In the first operation mode, when the AC voltage polarity determination unit 9g determines that the polarity of the AC voltage is positive as shown in FIG. 2, the current value detected by the AC current detection means 2 is stored in the threshold storage unit 9e. If the threshold value is greater than or equal to the positive threshold, the high side 4c of the second series circuit of the full bridge circuit 4 is opened, the low side 4d of the second series circuit of the full bridge circuit 4 is short-circuited, and the full bridge circuit 4 The low side 4b of the first series circuit outputs the PWM signal generated by the PWM signal generation unit 9c, and the high side 4a of the first series circuit of the full bridge circuit 4 is generated by the PWM signal generation unit 9c. By outputting a PWM signal that is complementary to the PWM signal or a PWM signal that takes into account a predetermined dead time from the PWM signal that is complementary to the PWM signal, the power factor of the AC power supply is improved. It performs to implement synchronous rectification. On the other hand, if the current value detected by the alternating current detection means 2 is less than the positive threshold value stored in the threshold value storage unit 9e, the low side 4b of the first series circuit of the full bridge circuit 4 is generated by the PWM signal generation unit 9c. The PWM signal is output, at least the low side 4d of the full bridge circuit 4 is opened, and synchronous rectification is partially prohibited, so that at least the low side 4d of the full bridge circuit 4 is in a diode state as shown in FIG. Therefore, the AC current from the AC power supply can be prevented from flowing in the opposite direction while improving the power factor of the AC power supply.
In addition, when the AC voltage polarity determination unit 9g determines that the polarity of the AC voltage is negative as shown in FIG. 2, the current value detected by the AC current detection means 2 is equal to or less than the negative threshold value stored in the threshold value storage unit 9e. If so, in addition to opening the low side 4d of the second series circuit of the full bridge circuit 4 and shorting the high side 4c of the second series circuit of the full bridge circuit 4, the first series of the full bridge circuit 4 The high side 4a of the circuit outputs the PWM signal generated by the PWM signal generation unit 9c, and the low side 4b of the first series circuit of the full bridge circuit 4 is complementary to the PWM signal generated by the PWM signal generation unit 9c. The power factor of the AC power supply is improved by outputting a PWM signal in consideration of a predetermined dead time from a PWM signal complementary to the PWM signal or a PWM signal complementary to the PWM signal To implement the synchronous rectification. On the other hand, if the current value detected by the AC current detection means 2 exceeds the negative threshold value stored in the threshold value storage unit 9e, the high side 4a of the first series circuit of the full bridge circuit 4 is generated by the PWM signal generation unit 9c. The PWM signal is output, and at least the high side 4c of the full bridge circuit 4 is opened, and synchronous rectification is partially prohibited, so that at least the high side 4c of the full bridge circuit 4 is a diode as shown in FIG. Therefore, the AC current from the AC power supply can be prevented from flowing in the opposite direction while improving the power factor of the AC power supply.
In the second operation mode, when the AC voltage polarity determination unit 9g determines that the polarity of the AC voltage is positive as shown in FIG. 2, the current value detected by the AC current detection means 2 is stored in the threshold storage unit 9e. If it is equal to or greater than the positive threshold, the high side 4a of the first series circuit of the full bridge circuit 4 and the low side 4d of the second series circuit of the full bridge circuit 4 are short-circuited and the first series of the full bridge circuit 4 is short-circuited. Synchronous rectification is performed by opening the low side 4b of the circuit and the high side 4c of the second series circuit of the full bridge circuit 4. On the other hand, if the current value detected by the AC current detecting means 2 is less than the positive threshold value stored in the threshold value storage unit 9e, the low side 4b of the first series circuit of the full bridge circuit 4 and the second value of the full bridge circuit 4 are used. In addition to the high side 4c of the series circuit, at least one of the high side 4a of the first series circuit of the full bridge circuit 4 or the low side 4d of the second series circuit of the full bridge circuit 4 is opened to partially perform synchronous rectification. By prohibiting, at least one of the high side 4a of the first series circuit of the full bridge circuit 4 or the low side 4d of the second series circuit of the full bridge circuit 4 is in a diode state as shown in FIG. It is possible to prevent the alternating current from the alternating current power supply from flowing in the reverse direction.
In addition, when the AC voltage polarity determination unit 9g determines that the polarity of the AC voltage is negative as shown in FIG. 2, the current value detected by the AC current detection means 2 is equal to or less than the negative threshold value stored in the threshold value storage unit 9e. If present, the low side 4b of the first series circuit of the full bridge circuit 4 and the high side 4c of the second series circuit of the full bridge circuit 4 are short-circuited, and the high side 4a of the first series circuit of the full bridge circuit 4 is short-circuited. And the synchronous rectification is implemented by opening the low side 4d of the second series circuit of the full bridge circuit 4. On the other hand, if the current value detected by the alternating current detection means 2 exceeds the negative threshold value stored in the threshold value storage unit 9e, the high side 4a of the first series circuit of the full bridge circuit 4 and the second value of the full bridge circuit 4 are used. In addition to the low side 4d of the series circuit, at least one of the low side 4b of the first series circuit of the full bridge circuit 4 or the high side 4c of the second series circuit of the full bridge circuit 4 is opened to partially perform synchronous rectification. By prohibiting, at least one of the low side 4b of the first series circuit of the full bridge circuit 4 or the high side 4c of the second series circuit of the full bridge circuit 4 is in a diode state as shown in FIG. It is possible to prevent the alternating current from the alternating current power supply from flowing in the reverse direction.
In the present invention, according to the magnitude relationship between the detected alternating current and a predetermined threshold value, a full bridge circuit in which a first and a second series circuit in which MOSFETs or GaN transistors are respectively connected in series is connected in parallel is provided. By implementing or prohibiting synchronous rectification, even when power factor improvement is not performed, AC current from the AC power supply does not flow in the reverse direction, realizing stable synchronous rectification and improving the conversion efficiency of the DC power supply device it can.
(Embodiment 2)
FIG. 5 is a diagram showing a configuration of a DC power supply device according to the second embodiment of the present invention.
Since the power factor correction apparatus according to the second embodiment of the present invention has the same circuit configuration as that of the first embodiment, only the operation of the threshold value storage unit 9e which is different from that of the first embodiment will be described.
In the threshold storage unit 9e, in order to avoid the frequent occurrence and prohibition of synchronous rectification in the vicinity of the threshold due to the influence of AC current ripple or the like, and to implement synchronous rectification more stably, the alternating current detection means The threshold value for performing synchronous rectification and the threshold value for prohibiting synchronous rectification are respectively provided by comparison with the current value detected from No. 2, and the absolute value of the threshold value for performing synchronous rectification is larger than the absolute value of the threshold value for prohibiting synchronous rectification. Set as follows. In addition, if the difference between the threshold value that allows synchronous rectification and the threshold value that prohibits synchronous rectification becomes excessively large, the effect of improving the conversion efficiency of the DC power supply device due to synchronous rectification will decrease, so depending on the ripple width of the AC current Then, the difference between the threshold value that permits synchronous rectification and the threshold value that prohibits synchronous rectification is changed. For example, the magnitude of the current ripple varies depending on the magnitude of the AC input current detected by the reactor 3 or the AC current detecting means 2 or whether or not the power factor of the AC power source is being improved. From the map stored in advance based on whether the AC input current detected by the reactor 3, the AC current detecting means 2 or the AC voltage phase detecting means 8 or the power factor of the AC power source is being improved. The magnitude of the current ripple is determined, and at least one of a threshold value for performing synchronous rectification and a threshold value for prohibiting synchronous rectification is changed according to the magnitude of the current ripple.
In the present invention, according to the magnitude relationship between the detected alternating current and a predetermined threshold value, a full bridge circuit in which a first and a second series circuit in which MOSFETs or GaN transistors are respectively connected in series is connected in parallel is provided. By implementing or prohibiting synchronous rectification, even when power factor improvement is not performed, AC current from the AC power supply does not flow in the reverse direction, realizing stable synchronous rectification and improving the conversion efficiency of the DC power supply device it can.

以上のように本発明にかかる直流電源装置は、力率改善を行っていない場合にも電流不連続モード時に同期整流を実施することで、交流電源からの交流電流が想定方向を逆側に流れることを回避しつつ直流電源装置の変換効率向上できるため、エアコンや冷蔵庫、洗濯機等の直流電源装置を用いた電化製品に適用出来る。 As described above, in the DC power supply device according to the present invention, even when the power factor is not improved, the AC current from the AC power supply flows in the opposite direction by performing synchronous rectification in the current discontinuous mode. Therefore, the conversion efficiency of the DC power supply device can be improved while avoiding this, so that it can be applied to electrical appliances using DC power supply devices such as air conditioners, refrigerators, and washing machines.

１交流電源
２交流電流検出手段
３リアクタ
４フルブリッジ回路
５平滑コンデンサ
６直流電圧検出手段
７負荷
８交流電圧位相検出手段
９制御部 DESCRIPTION OF SYMBOLS 1 AC power supply 2 AC current detection means 3 Reactor 4 Full bridge circuit 5 Smoothing capacitor 6 DC voltage detection means 7 Load 8 AC voltage phase detection means 9 Control part

Claims

A full bridge circuit in which first and second series circuits each having a MOSFET or a GaN transistor connected in series are connected in parallel; a reactor provided between the full bridge circuit and an AC power supply; and the full bridge A smoothing capacitor connected in parallel to the output side of the circuit; AC current detecting means for detecting an AC current from the AC power supply; AC voltage phase detecting means for detecting the phase of the AC voltage from the AC power supply; and the AC An AC voltage polarity determination unit that determines the polarity of the AC voltage based on information from the voltage phase detection means, and if the polarity of the AC voltage from the AC power supply is positive, the low side of the first series circuit is Short circuit and open circuit to improve the power factor so that the alternating current from the alternating current power source becomes a substantially sine wave, and open the low side of the first series circuit. In addition to short-circuiting the high side of the first series circuit only during the period, the low side of the second series circuit is short-circuited, and the high side of the second series circuit is opened to perform synchronous rectification. If the polarity of the AC voltage from the AC power source is negative, the high side of the first series circuit is short-circuited and opened so that the AC current from the AC power source becomes a substantially sine wave. In addition to performing a rate improvement and short-circuiting the low side of the first series circuit only during the period of opening the high side of the first series circuit, short-circuiting the high side of the second series circuit, If the first operation mode for performing synchronous rectification by opening the low side of the second series circuit and the polarity of the AC voltage from the AC power supply is positive, the high side of the first series circuit and Said second series If the polarity of the alternating voltage from the alternating current power source is negative, the low side of the first series circuit is subjected to synchronous rectification by opening the low side of the first series circuit and the high side of the second series circuit. Synchronous rectification is performed by short-circuiting the low side of the first series circuit and the high side of the second series circuit, and opening the high side of the first series circuit and the low side of the second series circuit. A threshold value storage unit that has a second operation mode and operates in either the first operation mode or the second operation mode, and stores positive and negative threshold values in advance. When the polarity of the AC voltage from the AC power supply is positive and the AC current is less than the positive threshold value stored in the threshold value storage unit, synchronization is achieved by opening at least the low side of the second series circuit. Rectification part When the polarity of the AC voltage from the AC power source is negative and the AC current exceeds the negative threshold value stored in the threshold value storage unit, at least the high side of the second series circuit is opened. Thus, the DC power supply device is characterized in that synchronous rectification is partially prohibited.

2. The DC power supply device according to claim 1, wherein absolute values of both positive and negative thresholds in the first operation mode are larger than those in the second operation mode.

3. The DC power supply device according to claim 1, wherein a threshold value for executing synchronous rectification and a threshold value for prohibiting synchronous rectification are provided.

Whether at least one of the threshold value for executing synchronous rectification or the threshold value for prohibiting synchronous rectification is the value of the reactor, the magnitude of the alternating current detected by the current detection means, or the power factor improvement of the alternating current power supply The DC power supply device according to claim 3, wherein the DC power supply device is changed according to