TWI756102B - Forward-flyback conversion device with zero current switching and method of zero current switching the same - Google Patents

Forward-flyback conversion device with zero current switching and method of zero current switching the same Download PDF

Info

Publication number
TWI756102B
TWI756102B TW110113059A TW110113059A TWI756102B TW I756102 B TWI756102 B TW I756102B TW 110113059 A TW110113059 A TW 110113059A TW 110113059 A TW110113059 A TW 110113059A TW I756102 B TWI756102 B TW I756102B
Authority
TW
Taiwan
Prior art keywords
switch
current
primary side
main switch
zero
Prior art date
Application number
TW110113059A
Other languages
Chinese (zh)
Other versions
TW202220355A (en
Inventor
周政彥
郭貝倉
王啟信
Original Assignee
亞元科技股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 亞元科技股份有限公司 filed Critical 亞元科技股份有限公司
Application granted granted Critical
Publication of TWI756102B publication Critical patent/TWI756102B/en
Publication of TW202220355A publication Critical patent/TW202220355A/en

Links

Images

Classifications

    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Landscapes

  • Dc-Dc Converters (AREA)

Abstract

A forward-flyback conversion device includes a forward-flyback converter and a control unit, and the forward-flyback converter includes a transformer, a transformer, a main switch, a capacitor bank, and a switch assembly. The transformer includes a primary-side winding and a secondary-side winding, and the main switch is coupled to the primary winding. The capacitor bank includes a first capacitor and a second capacitor connected in series, and one end of the secondary-side winding is coupled to the first capacitor and the second capacitor. The switch assembly is connected in parallel with the capacitor bank, and includes a first switch and a second switch connected in series, and the other end of the secondary-side winding is coupled to the first switch and the second switch. When the control unit turns on the main switch and the second switch, a primary-side current with resonance is generated in the primary-side winding, and after less than or equal to one-half of a natural period, the control unit turns off the second switch.

Description

具有零電流切換之順向-返馳式轉換裝置及其零電流切換方法Forward-flyback converter with zero-current switching and zero-current switching method

本發明係有關一種具有零電流切換之順向-返馳式轉換裝置及其零電流切換方法，尤指一種利用諧振延遲達成零電流切換的順向-返馳式轉換裝置及其切換方法。The present invention relates to a forward-flyback conversion device with zero current switching and a zero current switching method thereof, in particular to a forward-flyback conversion device and a switching method for achieving zero current switching by utilizing resonance delay.

現今比較常見的電源轉換器(power converter)之架構可以為順向式(forward)或者返馳式(flyback)，但無論是順向式還是返馳式電源轉換器，其都具有各自的優點。為了將兩者的優點整合為一，因此發展出將兩者電路整合為一的順向-返馳式電源轉換器(forward-flyback converter)。當操作於順向式轉換模式時，利用順向式作為倍壓迴路應用而提高增益比，並減少高增益所需的次級側繞線比。當操作於返馳式轉換模式時，利用返馳式（Flyback）在功率元件截止時輸出能量給負載。The architecture of the more common power converters today can be forward or flyback, but both forward and flyback power converters have their own advantages. In order to integrate the advantages of the two into one, a forward-flyback converter is developed which integrates the two circuits into one. When operating in forward switching mode, using forward as a voltage doubler loop application increases the gain ratio and reduces the secondary side winding ratio required for high gain. When operating in the flyback conversion mode, the flyback is used to output energy to the load when the power element is turned off.

如圖1所示為現有技術的順向-返馳式轉換裝置之波形圖。順向-返馳式電源轉換器中，初級側電流Ip係由變壓器初級側的電感電流Il與諧振電流Ir所合成。但是，由於在初級側的主開關被關斷時(即時間t3)，由電感電流Il與諧振電流Ir所合成初級側電流Ip並未下降到0，因此，在此時將主開關關斷的操作方式屬於硬切換(hard switch)。此種切換方式會造成切換損失較高、無法有效地降低電磁干擾(EMI)，也因為主開關的電流應力過大容易造成主開關損壞或者使用耐電流能力較高的主開關而增加成本的缺點。FIG. 1 is a waveform diagram of a forward-flyback conversion device in the prior art. In the forward-flyback type power converter, the primary side current Ip is synthesized by the inductor current Il and the resonant current Ir on the primary side of the transformer. However, since the primary side current Ip synthesized by the inductor current I1 and the resonant current Ir does not drop to 0 when the main switch on the primary side is turned off (ie, time t3), the main switch is turned off at this time. The mode of operation is a hard switch. This switching method will result in high switching loss, cannot effectively reduce electromagnetic interference (EMI), and also has the disadvantage of increasing the cost because the current stress of the main switch is too large, which may easily damage the main switch or increase the cost by using a main switch with a high current withstand capability.

為此，如何設計出一種具有零電流切換之順向-返馳式轉換裝置及其零電流切換方法，來降低主開關切換時的電流應力、切換損失與有效降低電磁干擾，乃為本案發明人所研究的重要課題。Therefore, how to design a forward-flyback converter with zero-current switching and a zero-current switching method to reduce the current stress, switching loss and effectively reduce electromagnetic interference during the switching of the main switch is the inventor of the present application. important topics studied.

本發明之目的在於提供一種具有零電流切換之順向-返馳式轉換裝置，解決現有技術之問題。The purpose of the present invention is to provide a forward-flyback conversion device with zero current switching to solve the problems of the prior art.

為達成前揭目的，本發明所提出的順向-返馳式轉換裝置包括：順向-返馳式轉換器與控制單元，且順向-返馳式轉換器包括：變壓器、主開關、電容組及開關組。變壓器包括初級側繞組與次級側繞組。主開關耦接初級側繞組。電容組包括串聯的第一電容與第二電容，且次級側繞組的一端耦接第一電容與第二電容。及開關組並聯電容組，且包括串聯的第一開關與第二開關，次級側繞組的另一端耦接第一開關與第二開關。控制單元耦接主開關與開關組。其中，控制單元導通主開關與第二開關時，在初級側繞組產生具有諧振的初級側電流，且在小於或等於二分之一的自然週期時，控制單元關斷第二開關。In order to achieve the purpose disclosed above, the forward-flyback conversion device proposed by the present invention includes: a forward-flyback converter and a control unit, and the forward-flyback converter includes: a transformer, a main switch, a capacitor group and switch group. The transformer includes a primary side winding and a secondary side winding. The main switch is coupled to the primary side winding. The capacitor group includes a first capacitor and a second capacitor connected in series, and one end of the secondary side winding is coupled to the first capacitor and the second capacitor. The switch group is connected in parallel with the capacitor group, and includes a first switch and a second switch connected in series, and the other end of the secondary side winding is coupled to the first switch and the second switch. The control unit is coupled to the main switch and the switch group. When the control unit turns on the main switch and the second switch, a primary side current with resonance is generated in the primary side winding, and when the natural period is less than or equal to half of the natural period, the control unit turns off the second switch.

於一實施例中，初級側電流由變壓器與電容組諧振時所產生的諧振電流與初級側繞組儲能時所產生的電感電流而合成。In one embodiment, the primary side current is synthesized by the resonant current generated when the transformer and the capacitor bank resonate and the inductor current generated when the primary side winding stores energy.

於一實施例中，自然週期為諧振電流的諧振頻率的倒數，且諧振頻率的由變壓器的漏電感與電容組的電容值決定。In one embodiment, the natural period is the inverse of the resonant frequency of the resonant current, and the resonant frequency is determined by the leakage inductance of the transformer and the capacitance value of the capacitor bank.

於一實施例中，在控制單元關斷主開關前的四分之一自然週期內，控制單元導通第二開關。In one embodiment, the control unit turns on the second switch within a quarter of a natural period before the control unit turns off the main switch.

於一實施例中，在控制單元關斷主開關時，控制單元同時關斷第二開關。In one embodiment, when the control unit turns off the main switch, the control unit turns off the second switch at the same time.

於一實施例中，當主開關達到工作責任時間，控制單元在初級側電流為零區間時，關斷主開關與第二開關。In one embodiment, when the main switch reaches the duty time, the control unit turns off the main switch and the second switch when the primary side current is zero.

本發明之再另一目的在於提供一種順向-返馳式轉換裝置之零電流切換方法，解決現有技術之問題。Yet another object of the present invention is to provide a zero-current switching method of a forward-flyback converter device to solve the problems of the prior art.

為達成前揭目的，本發明所提出的零電流切換方法係控制耦接於變壓器的初級側繞組的主開關，以及耦接於變壓器的次級側繞組的開關組，開關組並聯電容組，且包括串聯的第一開關與第二開關，其中零電流切換方法包括下列步驟：控制主開關、第一開關與第二開關的切換而將輸入電壓通過變壓器與電容組轉換為輸出電壓。導通主開關與第二開關，使初級側繞組產生具有諧振的初級側電流。及在導通主開關與第二開關，且小於或等於二分之一的自然週期時，關斷第二開關。In order to achieve the aforementioned purpose, the zero-current switching method proposed by the present invention controls the main switch coupled to the primary side winding of the transformer, and the switch group coupled to the secondary side winding of the transformer, the switch group is connected in parallel with the capacitor group, and It includes a first switch and a second switch connected in series, wherein the zero current switching method includes the following steps: controlling the switching of the main switch, the first switch and the second switch to convert the input voltage into an output voltage through a transformer and a capacitor bank. The main switch and the second switch are turned on, so that the primary side winding generates a primary side current with resonance. and when the main switch and the second switch are turned on and less than or equal to one half of the natural period, the second switch is turned off.

於一實施例中，初級側電流由變壓器與電容組諧振時所產生的諧振電流與初級側繞組儲能時所產生的電感電流而合成。In one embodiment, the primary side current is synthesized by the resonant current generated when the transformer and the capacitor bank resonate and the inductor current generated when the primary side winding stores energy.

於一實施例中，自然週期為諧振電流的諧振頻率的倒數，且諧振頻率的由變壓器的漏電感與電容組的電容值決定。In one embodiment, the natural period is the inverse of the resonant frequency of the resonant current, and the resonant frequency is determined by the leakage inductance of the transformer and the capacitance value of the capacitor bank.

於一實施例中，在關斷該主開關前的四分之一的自然週期內，導通第二開關。In one embodiment, the second switch is turned on within a quarter of a natural period before turning off the main switch.

於一實施例中，在關斷該主開關時，同時關斷第二開關。In one embodiment, when the main switch is turned off, the second switch is turned off at the same time.

於一實施例中，在到達工作責任時間時，初級側電流下降至零區間，且在初級側電流為零區間時，關斷主開關與第二開關。In one embodiment, when the duty time is reached, the primary side current drops to the zero interval, and when the primary side current is zero interval, the main switch and the second switch are turned off.

本發明之主要目的及功效在於，在控制訊號導通主開關期間，利用第二控制訊號控制第二開關的導通與關閉而使得諧振電流產生諧振延遲，以使初級側電流在特定的時間會下降至零區間後，控制單元再控制主開關關斷，可以使得主開關的關斷為零電流切換，進而達成降低開關切換時的損耗與提高電路效率之功效。The main purpose and effect of the present invention is to use the second control signal to control the turn-on and turn-off of the second switch during the period when the control signal turns on the main switch, so that the resonant current generates a resonant delay, so that the primary side current will drop to After the zero interval, the control unit then controls the main switch to be turned off, so that the main switch can be turned off with zero current switching, thereby achieving the effects of reducing switch switching losses and improving circuit efficiency.

為了能更進一步瞭解本發明為達成預定目的所採取之技術、手段及功效，請參閱以下有關本發明之詳細說明與附圖，相信本發明之目的、特徵與特點，當可由此得一深入且具體之瞭解，然而所附圖式僅提供參考與說明用，並非用來對本發明加以限制者。In order to further understand the technology, means and effect adopted by the present invention to achieve the predetermined purpose, please refer to the following detailed description and accompanying drawings of the present invention. For specific understanding, however, the accompanying drawings are only provided for reference and description, and are not intended to limit the present invention.

茲有關本發明之技術內容及詳細說明，配合圖式說明如下。The technical content and detailed description of the present invention are described as follows in conjunction with the drawings.

請參見圖2為本發明具有零電流切換之順向-返馳式轉換裝置之電路方塊圖。順向-返馳式轉換裝置10接收輸入電壓Vin，且轉換輸入電壓Vin為輸出電壓Vo，以提供輸出電壓Vo對負載20供電。順向-返馳式轉換裝置10包括順向-返馳式轉換器12與控制單元14，且控制單元14用以控制順向-返馳式轉換器12將輸入電壓Vin轉換為輸出電壓Vo。順向-返馳式轉換器12包括變壓器122、主開關124、電容組126及開關組128，且變壓器122包括初級側繞組122-1與次級側繞組122-2。初級側繞組122-1的一端接收輸入電壓Vin，且初級側繞組122-1的另一端耦接主開關124。電容組126包括串聯的第一電容C1與第二電容C2，且次級側繞組122-2的一端耦接第一電容C1與第二電容C2之間的節點。開關組128並聯電容組126，且包括串聯的第一開關Q1與第二開關Q2，次級側繞組122-2的另一端耦接第一開關Q1與第二開關Q2。其中，變壓器122更包括等效的初級側等效漏感Llk1、次級側等效漏感Llk2及激磁電感Lm，其應用將會於下文中有進一步地說明。Please refer to FIG. 2 , which is a circuit block diagram of the forward-flyback conversion device with zero current switching according to the present invention. The forward-flyback conversion device 10 receives the input voltage Vin, and converts the input voltage Vin into the output voltage Vo, so as to provide the output voltage Vo to power the load 20 . The forward-flyback converter 10 includes a forward-flyback converter 12 and a control unit 14 , and the control unit 14 is used for controlling the forward-flyback converter 12 to convert the input voltage Vin into the output voltage Vo. The forward-flyback converter 12 includes a transformer 122, a main switch 124, a capacitor bank 126 and a switch bank 128, and the transformer 122 includes a primary side winding 122-1 and a secondary side winding 122-2. One end of the primary side winding 122 - 1 receives the input voltage Vin, and the other end of the primary side winding 122 - 1 is coupled to the main switch 124 . The capacitor group 126 includes a first capacitor C1 and a second capacitor C2 connected in series, and one end of the secondary side winding 122-2 is coupled to a node between the first capacitor C1 and the second capacitor C2. The switch group 128 is connected in parallel with the capacitor group 126, and includes a first switch Q1 and a second switch Q2 connected in series, and the other end of the secondary side winding 122-2 is coupled to the first switch Q1 and the second switch Q2. The transformer 122 further includes an equivalent primary-side equivalent leakage inductance Llk1 , a secondary-side equivalent leakage inductance Llk2 and a magnetizing inductance Lm, the application of which will be further described below.

控制單元14耦接主開關124、第一開關Q1及第二開關Q2，且提供控制訊號Sc、第一控制訊號Sc1及第二控制訊號Sc2分別控制主開關124、第一開關Q1及第二開關Q2的切換，以控制順向-返馳式轉換器12將輸入電壓Vin轉換為輸出電壓Vo。其中，控制單元14提供控制訊號Sc控制主開關124導通時，順向-返馳式轉換器12***作於順向式轉換模式，且控制主開關124關斷時，順向-返馳式轉換器12***作於返馳式轉換模式。順向-返馳式轉換器12的特點在於，順向-返馳式轉換器12可以補足典型的返馳式轉換無法設計在高功率輸出之缺點。當操作於順向式轉換模式時(即主開關124導通時)，利用順向式（Forward）做為倍壓迴路應用而提高增益比，並減少高增益所需的次級側繞線比。當操作於返馳式轉換模式時(即主開關124關斷時)，利用返馳式（Flyback）在功率元件截止時輸出能量給負載20。值得一提，於本發明之一實施例中，順向-返馳式轉換裝置10可包括整流單元10-1。整流單元10-1耦接順向-返馳式轉換器12，且將交流電壓Vac整流為直流的輸入電壓Vin，以提供直流的輸入電壓Vin至順向-返馳式轉換器12。The control unit 14 is coupled to the main switch 124, the first switch Q1 and the second switch Q2, and provides the control signal Sc, the first control signal Sc1 and the second control signal Sc2 to control the main switch 124, the first switch Q1 and the second switch respectively The switching of Q2 controls the forward-flyback converter 12 to convert the input voltage Vin to the output voltage Vo. Wherein, when the control unit 14 provides the control signal Sc to control the main switch 124 to be turned on, the forward-flyback converter 12 is operated in the forward conversion mode, and when the main switch 124 is controlled to be turned off, the forward-flyback converter 124 is turned off. The controller 12 is operated in a flyback switching mode. The feature of the forward-flyback converter 12 is that the forward-flyback converter 12 can make up for the disadvantage that the typical flyback converter cannot be designed for high power output. When operating in the forward conversion mode (ie when the main switch 124 is turned on), the forward is used as a voltage doubler loop application to increase the gain ratio and reduce the secondary side winding ratio required for high gain. When operating in the flyback conversion mode (ie, when the main switch 124 is turned off), the flyback is used to output energy to the load 20 when the power element is turned off. It is worth mentioning that, in an embodiment of the present invention, the forward-flyback conversion device 10 may include a rectifying unit 10-1. The rectifying unit 10 - 1 is coupled to the forward-flyback converter 12 and rectifies the AC voltage Vac into a DC input voltage Vin to provide the DC input voltage Vin to the forward-flyback converter 12 .

請參閱圖3為本發明具有零電流切換之順向-返馳式轉換裝置之波形圖，復配合參閱圖1~2。如圖1所示，由於在控制單元14欲關斷主開關124時(即圖1的時間t3)，流過主開關124的初級側電流Ip仍然很高，因此在此時關斷主開關124的電流應力很大，屬於硬切換式的操作。此操作會造成開關的損耗大、電路效率不佳、無法有效地降低電磁干擾、主開關易損壞之缺點。本發明之主要目的在於，在控制訊號Sc導通主開關124期間，利用第二控制訊號Sc2控制第二開關Q2的導通與關閉而使得諧振電流Ir產生諧振延遲，以使初級側電流Ip在特定的時間會下降至零區間。在初級側電流Ip下降至零區間時，控制單元14再控制主開關124關斷，可以使得主開關124的關斷為零電流切換(即零電流關斷)，進而達成降低開關切換時的損耗、提高電路效率與有效地降低電磁干擾之功效。Please refer to FIG. 3 for a waveform diagram of the forward-flyback conversion device with zero-current switching according to the present invention, and refer to FIGS. 1-2 in combination. As shown in FIG. 1 , when the control unit 14 wants to turn off the main switch 124 (ie, time t3 in FIG. 1 ), the primary side current Ip flowing through the main switch 124 is still high, so the main switch 124 is turned off at this time. The current stress is very large, which belongs to the hard switching operation. This operation will lead to the disadvantages of large switch loss, poor circuit efficiency, inability to effectively reduce electromagnetic interference, and easy damage to the main switch. The main purpose of the present invention is to use the second control signal Sc2 to control the turn-on and turn-off of the second switch Q2 during the period when the control signal Sc turns on the main switch 124 to cause the resonant current Ir to generate a resonant delay, so that the primary side current Ip is at a specific Time will drop to the zero zone. When the primary side current Ip drops to the zero interval, the control unit 14 then controls the main switch 124 to turn off, so that the turn-off of the main switch 124 is zero-current switching (ie, zero-current turn-off), thereby reducing the switching loss during switching. , Improve circuit efficiency and effectively reduce the effect of electromagnetic interference.

請參閱圖3，在時間t0時，控制單元14提供控制訊號Sc導通主開關124，且同步地提供第二控制訊號Sc2導通第二開關Q2。在主開關124被導通時，輸入電壓Vin與接地端產生電位差，因此電流流過激磁電感Lm而產生電感電流Il。此時，由於第二開關Q2也被導通，因此使得初級側等效漏感Llk1、次級側等效漏感Llk2、第一電容C1及第二電容C2構成諧振電路Cr。此諧振電路Cr的總電感量換算至變壓器的初級側可表示為Llk1+N2Llk2，且總電容量換算至變壓器的初級側可表示為(C1+C2)N2。其中，N為變壓器122的匝數比。通過此諧振電路Cr的諧振，會使得初級側繞組122-1感應到諧振電流Ir，因此電感電流Il與諧振電流Ir所合成的電流即為初級側電流Ip。Referring to FIG. 3 , at time t0 , the control unit 14 provides the control signal Sc to turn on the main switch 124 , and simultaneously provides the second control signal Sc2 to turn on the second switch Q2 . When the main switch 124 is turned on, a potential difference is generated between the input voltage Vin and the ground terminal, so the current flows through the magnetizing inductor Lm to generate the inductor current I1. At this time, since the second switch Q2 is also turned on, the primary side equivalent leakage inductance Llk1 , the secondary side equivalent leakage inductance Llk2 , the first capacitor C1 and the second capacitor C2 form the resonance circuit Cr. The total inductance of the resonant circuit Cr converted to the primary side of the transformer can be expressed as Llk1+N2Llk2, and the total capacitance converted to the primary side of the transformer can be expressed as (C1+C2)N2. where N is the turns ratio of the transformer 122 . Through the resonance of the resonant circuit Cr, the primary side winding 122-1 induces the resonant current Ir, so the combined current of the inductor current Il and the resonant current Ir is the primary side current Ip.

進一步而言，諧振電路Cr會使得諧振電流Ir為具有諧振頻率的電流，此諧振頻率可通過初級側等效漏感Llk1、次級側等效漏感Llk2、第一電容C1及第二電容C2的數值而獲得。意即，諧振頻率由該變壓器的漏電感(初級側等效漏感Llk1與次級側等效漏感Llk2)與電容組(第一電容C1及第二電容C2)的電容值決定。諧振頻率的倒數即為自然週期Tn，在此先決條件下，通過對諧振電路Cr的設計使得控制單元14欲關斷主開關124時(時間t3)時，初級側電流Ip會因為諧振電流Ir諧振的影響而下降至0。因此，初級側電流Ip在控制訊號Sc關斷主開關124時的電流值，可以通過調整諧振電路Cr的參數(即初級側等效漏感Llk1、次級側等效漏感Llk2、第一電容C1及第二電容C2)而改變。Further, the resonant circuit Cr makes the resonant current Ir a current having a resonant frequency, and the resonant frequency can be passed through the equivalent leakage inductance Llk1 on the primary side, the equivalent leakage inductance Llk2 on the secondary side, the first capacitor C1 and the second capacitor C2. value obtained. That is, the resonance frequency is determined by the leakage inductance of the transformer (the equivalent leakage inductance Llk1 on the primary side and the equivalent leakage inductance Llk2 on the secondary side) and the capacitance values of the capacitor group (the first capacitor C1 and the second capacitor C2). The reciprocal of the resonant frequency is the natural period Tn. Under this prerequisite, when the control unit 14 wants to turn off the main switch 124 (time t3) by designing the resonant circuit Cr, the primary side current Ip will resonate due to the resonant current Ir. drop to 0. Therefore, the current value of the primary side current Ip when the control signal Sc turns off the main switch 124 can be adjusted by adjusting the parameters of the resonant circuit Cr (ie, the equivalent leakage inductance Llk1 of the primary side, the equivalent leakage inductance Llk2 of the secondary side, the first capacitor C1 and the second capacitance C2).

復參閱圖3，在時間為t0至t1時，電流持續流過激磁電感Lm而使初級側繞組122-1持續儲能，使得電感電流Il持續上升。此時，由於第二開關Q2導通，因此使第一電容C1與第二電容C2充電而使諧振電路Cr諧振。此諧振通過變壓器122的耦合效應，於初級側繞組122-1產生到正半週的諧振電流Ir。此諧振電流Ir加上電感電流Il即為初級側電流Ip，所以初級側電流Ip呈現大致上為半波的形狀。在到達大致上等於(其可以為小於或等於)二分之一的自然週期Tn(時間t1)時，諧振電流Ir的正半週接近0而準備進入負半週。此時，控制單元14關斷第二開關Q2，使初級側電流Ip暫時停止向負半週諧振。Referring to FIG. 3 again, when the time is from t0 to t1, the current continues to flow through the magnetizing inductance Lm, so that the primary side winding 122-1 continues to store energy, so that the inductor current I1 continues to rise. At this time, since the second switch Q2 is turned on, the first capacitor C1 and the second capacitor C2 are charged to resonate the resonance circuit Cr. This resonance generates a resonant current Ir to the positive half cycle in the primary side winding 122 - 1 through the coupling effect of the transformer 122 . The resonant current Ir plus the inductor current Il is the primary-side current Ip, so the primary-side current Ip has a substantially half-wave shape. Upon reaching a natural period Tn (time t1 ) approximately equal to (which may be less than or equal to) one-half, the positive half cycle of the resonant current Ir approaches 0 and is ready to enter the negative half cycle. At this time, the control unit 14 turns off the second switch Q2 to temporarily stop the primary side current Ip from resonating toward the negative half cycle.

在時間為t1至t2時，由於第二開關Q2被關斷，因此諧振電流Ir維持在0。由於電流持續流過激磁電感Lm而使初級側繞組122-1持續儲能，電感電流Il仍然持續上升。因此，初級側電流Ip呈現大致上等於電感電流Il的波形。在時間為t2時，為控制單元欲關斷主開關124前的四分之一的自然週期Tn內。此時，控制單元14導通第二開關Q2，使得諧振電流Ir再次開始諧振而使諧振電流Ir向負半週的方向降低。利用此時間點導通第二開關Q2可以使得控制單元14欲關斷主開關124時，初級側電流Ip恰巧下降至0。意即，初級側方向繼續產生諧振電流Ir，使諧振電流Ir與電感電流Il在初級側方向相互抵消，而使初級側電流Ip下降至零區間。值得一提，時間在t1至t2之間並非為四分之一的自然週期Tn。具體而言，由於自然週期Tn為時間固定的週期，但主開關124的切換週期為控制單元14根據回授順向-返馳式轉換器10所回授的訊號而調整的，其為不固定的週期。因此，時間在t1至t2之間例如但不限於，可能間隔了多個自然週期Tn。From t1 to t2, since the second switch Q2 is turned off, the resonant current Ir is maintained at 0. Since the current continues to flow through the magnetizing inductor Lm, the primary side winding 122-1 continues to store energy, and the inductor current I1 continues to rise. Therefore, the primary side current Ip exhibits a waveform substantially equal to the inductor current Il. When the time is t2, it is within a quarter of the natural period Tn before the control unit wants to turn off the main switch 124. At this time, the control unit 14 turns on the second switch Q2, so that the resonance current Ir starts to resonate again and the resonance current Ir decreases in the direction of the negative half cycle. Turning on the second switch Q2 at this time point can make the primary side current Ip drop to 0 when the control unit 14 wants to turn off the main switch 124 . That is, the resonant current Ir continues to be generated in the primary side direction, so that the resonant current Ir and the inductor current Il cancel each other out in the primary side direction, and the primary side current Ip drops to the zero range. It is worth mentioning that the time between t1 and t2 is not a quarter of the natural period Tn. Specifically, since the natural period Tn is a fixed time period, the switching period of the main switch 124 is adjusted by the control unit 14 according to the feedback signal from the forward-flyback converter 10 , which is not fixed. cycle. Therefore, the time between t1 and t2 may be separated by a number of natural periods Tn, for example, but not limited to.

在時間為t2至t3時，諧振電流Ir持續向負半週的方向降低，且電感電流Il仍然持續上升之故，因此初級側電流Ip呈現諧振電流Ir與電感電流Il相互抵銷的狀況而逐漸下降。在時間為t3時，初級側電流Ip會因為諧振電流Ir與電感電流Il相互抵銷的原因而下降至零區間Z。其中，零區間Z所指的是電流大致上為0，其可以包括一個微小的誤差範圍(例如但不限於正負3%的範圍)。此時，控制單元14關斷主開關124與第二開關Q2。在時間為t3關斷主開關124的原因在於，此時的初級側電流Ip恰巧下降至零區間Z，主開關124兩端的電流應力很小而使得在此時可進行主開關124的零電流關斷。由於主開關124操作在零電流關斷之故，主開關124的功率損耗小，可以提高電路整體效率、降低主開關124損壞的風險及有效地降低電磁干擾。其中，時間t0~t3為工作責任時間，工作責任時間為控制單元14根據順向-返馳式轉換裝置10所回授的訊號而設定。工作責任時間可能為不固定，其原因在於順向-返馳式轉換裝置10可能操作於變頻模式，而時間t0至t3即為一個工作責任週期。From t2 to t3, the resonant current Ir continues to decrease in the direction of the negative half cycle, and the inductor current I1 continues to rise, so the primary side current Ip presents a situation in which the resonant current Ir and the inductor current I1 cancel each other out and gradually decline. At time t3, the primary side current Ip will drop to the zero interval Z due to the mutual cancellation of the resonant current Ir and the inductor current I1. Wherein, the zero interval Z refers to that the current is substantially 0, which may include a small error range (for example, but not limited to a range of plus or minus 3%). At this time, the control unit 14 turns off the main switch 124 and the second switch Q2. The reason why the main switch 124 is turned off at time t3 is that the primary side current Ip at this time happens to drop to the zero interval Z, and the current stress across the main switch 124 is very small, so that the zero-current shutdown of the main switch 124 can be performed at this time. break. Since the main switch 124 operates at zero current turn-off, the power loss of the main switch 124 is small, which can improve the overall efficiency of the circuit, reduce the risk of damage to the main switch 124 and effectively reduce electromagnetic interference. The time t0 to t3 is the work responsibility time, and the work responsibility time is set by the control unit 14 according to the signal returned by the forward-flyback conversion device 10 . The duty duty time may not be fixed because the forward-flyback conversion device 10 may operate in the frequency conversion mode, and the time t0 to t3 is a duty duty cycle.

值得一提，於本發明之一實施例中，在時間為t3時，初級側電流Ip下降至0為較佳的實施方式，但是因諧振電路Cr的設計及數值的計算在實際應用中會具有非理想上的落差，因此在實務上可以依照實際需求，合理的擴大零區間Z的範圍(例如但不限於正負10%的區間等)。It is worth mentioning that in one embodiment of the present invention, when the time is t3, the primary side current Ip drops to 0, which is a better implementation. The gap is not ideal, so in practice, the scope of the zero interval Z can be reasonably expanded according to the actual needs (such as but not limited to the interval of plus or minus 10%, etc.).

請參閱圖4為本發明順向-返馳式轉換裝置之零電流切換方法流程圖，復配合參閱圖2~3。順向-返馳式轉換裝置的零電流切換方法首先包括，控制主開關與開關組的切換而將輸入電壓通過變壓器與電容組轉換為輸出電壓(S100)。控制單元14分別提供控制訊號Sc、第一控制訊號Sc1及第二控制訊號Sc2控制主開關124、第一開關Q1及第二開關Q2的切換，以控制順向-返馳式轉換器12將輸入電壓Vin轉換為輸出電壓Vo。Please refer to FIG. 4 for a flow chart of the zero-current switching method of the forward-flyback conversion device of the present invention, and refer to FIGS. 2 to 3 in combination. The zero-current switching method of the forward-flyback conversion device firstly includes controlling the switching of the main switch and the switch group to convert the input voltage into the output voltage through the transformer and the capacitor group ( S100 ). The control unit 14 respectively provides the control signal Sc, the first control signal Sc1 and the second control signal Sc2 to control the switching of the main switch 124, the first switch Q1 and the second switch Q2, so as to control the forward-flyback converter 12 to input the input The voltage Vin is converted into the output voltage Vo.

然後，導通主開關與第二開關，使初級側繞組產生具有諧振的初級側電流(S120)。在主開關124被導通時，輸入電壓Vin與接地端產生電位差，因此電流流過激磁電感Lm而產生電感電流Il。此時，由於第二開關Q2也被導通，因此使得初級側等效漏感Llk1、次級側等效漏感Llk2、第一電容C1及第二電容C2構成諧振電路Cr。通過此諧振電路Cr的諧振，會使得初級側繞組122-1感應到諧振電流Ir，因此電感電流Il與諧振電流Ir所合成的電流即為初級側電流Ip。進一步而言，諧振電路Cr會使得諧振電流Ir為具有諧振頻率的電流，此諧振頻率可通過初級側等效漏感Llk1、次級側等效漏感Llk2、第一電容C1及第二電容C2的數值而獲得。意即，諧振頻率的由該變壓器的漏電感(初級側等效漏感Llk1與次級側等效漏感Llk2)與電容組(第一電容C1及第二電容C2)的電容值決定。Then, the main switch and the second switch are turned on, so that the primary side winding generates a primary side current with resonance ( S120 ). When the main switch 124 is turned on, a potential difference is generated between the input voltage Vin and the ground terminal, so the current flows through the magnetizing inductor Lm to generate the inductor current I1. At this time, since the second switch Q2 is also turned on, the primary side equivalent leakage inductance Llk1 , the secondary side equivalent leakage inductance Llk2 , the first capacitor C1 and the second capacitor C2 form the resonance circuit Cr. Through the resonance of the resonant circuit Cr, the primary side winding 122-1 induces the resonant current Ir, so the combined current of the inductor current Il and the resonant current Ir is the primary side current Ip. Further, the resonant circuit Cr makes the resonant current Ir a current having a resonant frequency, and the resonant frequency can be passed through the equivalent leakage inductance Llk1 on the primary side, the equivalent leakage inductance Llk2 on the secondary side, the first capacitor C1 and the second capacitor C2. value obtained. That is, the resonance frequency is determined by the leakage inductance of the transformer (the equivalent leakage inductance Llk1 on the primary side and the equivalent leakage inductance Llk2 on the secondary side) and the capacitance values of the capacitor group (the first capacitor C1 and the second capacitor C2).

最後，在導通主開關與第二開關，且小於或等於二分之一的自然週期時，關斷第二開關(S140)。在控制訊號Sc導通主開關124期間，利用第二控制訊號Sc2控制第二開關Q2的導通與關閉而使得諧振電流Ir產生諧振延遲，以使初級側電流Ip在特定的時間會下降至零區間。在初級側電流Ip下降至零區間時，控制單元14再控制主開關124關斷，可以使得主開關124的關斷為零電流切換，進而達成降低開關切換時的損耗與提高電路效率之功效。Finally, when the main switch and the second switch are turned on and less than or equal to one half of the natural period, the second switch is turned off ( S140 ). During the period when the control signal Sc turns on the main switch 124, the second control signal Sc2 is used to control the turn-on and turn-off of the second switch Q2 to cause the resonance current Ir to generate a resonance delay, so that the primary side current Ip drops to the zero interval at a specific time. When the primary side current Ip drops to the zero range, the control unit 14 then controls the main switch 124 to turn off, so that the main switch 124 can be turned off to zero current switching, thereby reducing switching losses and improving circuit efficiency.

在控制訊號Sc導通主開關124期間中，當到達大致上等於(其可以為小於或等於)二分之一的自然週期Tn(時間t1)時，諧振電流Ir的正半週接近0(即零區間Z)而準備進入負半週。此時，控制單元14關斷第二開關Q2，使初級側電流Ip暫時停止向負半週諧振。當控制單元欲關斷主開關124前的四分之一的自然週期Tn內(時間t2)，控制單元14導通第二開關Q2，使得諧振電流Ir再次開始諧振而使諧振電流Ir向負半週的方向降低。當控制單元關斷主開關124時(時間t3)，初級側電流Ip會因為諧振電流Ir與電感電流Il相互抵銷的原因而下降至零區間Z。此時的初級側電流Ip恰巧下降至零區間Z，主開關124兩端的電流應力很小而使得在此時可進行主開關124的零電流關斷。同時，控制單元14也關斷第二開關Q2。During the period during which the control signal Sc turns on the main switch 124, when the natural period Tn (time t1) which is approximately equal to (which may be less than or equal to) half of the natural period Tn (time t1) is reached, the positive half period of the resonant current Ir is close to 0 (ie zero Zone Z) and prepare to enter the negative half cycle. At this time, the control unit 14 turns off the second switch Q2 to temporarily stop the primary side current Ip from resonating toward the negative half cycle. When the control unit wants to turn off the main switch 124 within a quarter of the natural period Tn (time t2), the control unit 14 turns on the second switch Q2, so that the resonant current Ir starts to resonate again and the resonant current Ir goes to the negative half cycle direction decreases. When the control unit turns off the main switch 124 (time t3), the primary side current Ip will drop to the zero interval Z due to the mutual cancellation of the resonant current Ir and the inductor current I1. The primary-side current Ip at this time happens to drop to the zero interval Z, and the current stress across the main switch 124 is very small, so that the zero-current turn-off of the main switch 124 can be performed at this time. At the same time, the control unit 14 also turns off the second switch Q2.

值得一提，於本發明之一實施例中，上述零電流切換方法並不限定僅能操作於圖2所出示的順向-返馳式轉換裝置10。具體而言，由於順向-返馳式轉換裝置具有可變形的電路結構(例如但不限於初級側或次級側使用全橋電路等變形的結構)，因此上述操作方法同樣適用於經變形的順向-返馳式轉換裝置的電路結構，其控制單元14所控制的方式可施行於經變形的順向-返馳式轉換裝置中，具有相似操作特徵的開關。It is worth mentioning that, in an embodiment of the present invention, the above-mentioned zero-current switching method is not limited to only operate on the forward-flyback conversion device 10 shown in FIG. 2 . Specifically, since the forward-flyback conversion device has a deformable circuit structure (such as but not limited to a deformed structure using a full-bridge circuit on the primary side or the secondary side), the above-mentioned operation method is also applicable to the deformed circuit structure. The circuit structure of the forward-flyback switching device, and the manner controlled by the control unit 14 can be implemented in a modified forward-flyback switching device, with switches having similar operating characteristics.

以上所述，僅為本發明較佳具體實施例之詳細說明與圖式，惟本發明之特徵並不侷限於此，並非用以限制本發明，本發明之所有範圍應以下述之申請專利範圍為準，凡合於本發明申請專利範圍之精神與其類似變化之實施例，皆應包含於本發明之範疇中，任何熟悉該項技藝者在本發明之領域內，可輕易思及之變化或修飾皆可涵蓋在以下本案之專利範圍。The above descriptions are only detailed descriptions and drawings of the preferred embodiments of the present invention, but the features of the present invention are not limited thereto, and are not intended to limit the present invention. The entire scope of the present invention should be defined as the following claims All the embodiments that conform to the spirit of the scope of the patent application of the present invention and similar variations thereof shall be included in the scope of the present invention. Modifications can be covered by the following patent scope of this case.

10:順向-返馳式轉換裝置10: Forward-flyback conversion device

10-1:整流單元10-1: Rectifier unit

12:順向-返馳式轉換器12: Forward-Flyback Converter

122:變壓器122: Transformer

122-1:初級側繞組122-1: Primary side winding

122-2:次級側繞組122-2: Secondary side winding

Llk1:初級側等效漏感Llk1: Primary side equivalent leakage inductance

Llk2:次級側等效漏感Llk2: secondary side equivalent leakage inductance

Lm:激磁電感Lm: magnetizing inductance

124:主開關124: main switch

126:電容組126: Capacitor bank

C1:第一電容C1: first capacitor

C2:第二電容C2: second capacitor

128:開關組128: switch group

Cr:諧振電路Cr: resonant circuit

Q1:第一開關Q1: The first switch

Q2:第二開關Q2: Second switch

14:控制單元14: Control unit

20:負載20: load

Vin:輸入電壓Vin: input voltage

Vo:輸出電壓Vo: output voltage

Vac:交流電壓Vac: AC voltage

Sc:控制訊號Sc: control signal

Sc1:第一控制訊號Sc1: The first control signal

Sc2:第二控制訊號Sc2: The second control signal

Ip:初級側電流Ip: Primary side current

Il:電感電流Il: inductor current

Ir:諧振電流Ir: resonant current

Tn:自然週期Tn: natural cycle

Z:零區間Z: zero interval

t0~t3:時間t0~t3: time

圖1為現有技術的順向-返馳式轉換裝置之波形圖；1 is a waveform diagram of a forward-flyback conversion device in the prior art;

圖2為本發明具有零電流切換之順向-返馳式轉換裝置之電路方塊圖；FIG. 2 is a circuit block diagram of a forward-flyback conversion device with zero current switching according to the present invention;

圖3為本發明具有零電流切換之順向-返馳式轉換裝置之波形圖；及3 is a waveform diagram of a forward-flyback conversion device with zero current switching according to the present invention; and

圖4為本發明順向-返馳式轉換裝置之零電流切換方法流程圖。FIG. 4 is a flow chart of the zero current switching method of the forward-flyback conversion device of the present invention.

Ip:初級側電流 Ip: Primary side current

Il:電感電流 Il: inductor current

Ir:諧振電流 Ir: resonant current

Tn:自然週期 Tn: natural cycle

Z:零區間 Z: zero interval

t0~t3:時間 t0~t3: time

Claims (12)

一種具有零電流切換之順向-返馳式轉換裝置，包括： 一順向-返馳式轉換器，包括： 一變壓器，包括一初級側繞組與一次級側繞組； 一主開關，耦接該初級側繞組； 一電容組，包括串聯的一第一電容與一第二電容，且該次級側繞組的一端耦接該第一電容與該第二電容；及 一開關組，並聯該電容組，且包括串聯的一第一開關與一第二開關，該次級側繞組的另一端耦接該第一開關與該第二開關；及 一控制單元，耦接該主開關與該開關組； 其中，該控制單元導通該主開關與該第二開關時，在該初級側繞組產生具有諧振的一初級側電流，且在小於或等於二分之一的一自然週期時，該控制單元關斷該第二開關。 A forward-flyback conversion device with zero current switching, comprising: A forward-flyback converter, including: a transformer, including a primary side winding and a secondary side winding; a main switch, coupled to the primary side winding; a capacitor group including a first capacitor and a second capacitor connected in series, and one end of the secondary side winding is coupled to the first capacitor and the second capacitor; and a switch group, connected in parallel with the capacitor group, and comprising a first switch and a second switch connected in series, and the other end of the secondary side winding is coupled to the first switch and the second switch; and a control unit, coupled to the main switch and the switch group; Wherein, when the control unit turns on the main switch and the second switch, a primary side current with resonance is generated in the primary side winding, and when a natural period less than or equal to one half, the control unit is turned off the second switch. 如請求項1所述之順向-返馳式轉換裝置，其中該初級側電流由該變壓器與該電容組諧振時所產生的一諧振電流與該初級側繞組儲能時所產生的一電感電流合成。The forward-flyback conversion device of claim 1, wherein the primary side current is a resonant current generated when the transformer and the capacitor bank resonate and an inductor current generated when the primary side winding stores energy synthesis. 如請求項2所述之順向-返馳式轉換裝置，其中該自然週期為該諧振電流的一諧振頻率的倒數，且該諧振頻率的由該變壓器的一漏電感與該電容組的一電容值決定。The forward-flyback conversion device of claim 2, wherein the natural period is the inverse of a resonant frequency of the resonant current, and the resonant frequency is determined by a leakage inductance of the transformer and a capacitance of the capacitor bank value decision. 如請求項1所述之順向-返馳式轉換裝置，其中在該控制單元關斷該主開關前的四分之一該自然週期內，該控制單元導通該第二開關。The forward-flyback conversion device of claim 1, wherein the control unit turns on the second switch within a quarter of the natural period before the control unit turns off the main switch. 如請求項1所述之順向-返馳式轉換裝置，其中在該控制單元關斷該主開關時，該控制單元同時關斷該第二開關。The forward-flyback conversion device as claimed in claim 1, wherein when the control unit turns off the main switch, the control unit turns off the second switch at the same time. 如請求項1所述之順向-返馳式轉換裝置，其中當該主開關達到一工作責任時間，該控制單元在該初級側電流為該零區間時，關斷該主開關與該第二開關。The forward-flyback conversion device as claimed in claim 1, wherein when the main switch reaches an operating duty time, the control unit turns off the main switch and the second switch when the primary side current is in the zero interval switch. 一種順向-返馳式轉換裝置之零電流切換方法，係控制耦接於一變壓器的一初級側繞組的一主開關，以及耦接於該變壓器的一次級側繞組的一開關組，該開關組並聯一電容組，且包括串聯的一第一開關與一第二開關，其中該零電流切換方法包括下列步驟： 控制該主開關、該第一開關與該第二開關的切換而將一輸入電壓通過該變壓器與該電容組轉換為一輸出電壓； 導通該主開關與該第二開關，使該初級側繞組產生具有諧振的一初級側電流；及 在導通該主開關與該第二開關，且小於或等於二分之一的一自然週期時，關斷該第二開關。 A zero-current switching method of a forward-flyback conversion device controls a main switch coupled to a primary side winding of a transformer, and a switch group coupled to a secondary side winding of the transformer, the switch A capacitor group is connected in parallel, and includes a first switch and a second switch connected in series, wherein the zero-current switching method includes the following steps: Controlling the switching of the main switch, the first switch and the second switch to convert an input voltage into an output voltage through the transformer and the capacitor bank; turning on the main switch and the second switch so that the primary side winding generates a primary side current with resonance; and When the main switch and the second switch are turned on and less than or equal to one half of a natural period, the second switch is turned off. 如請求項7所述之零電流切換方法，其中該初級側電流由該變壓器與該電容組諧振時所產生的一諧振電流與該初級側繞組儲能時所產生的一電感電流合成。The zero-current switching method of claim 7, wherein the primary side current is synthesized by a resonant current generated when the transformer and the capacitor bank resonate and an inductor current generated when the primary side winding stores energy. 如請求項8所述之零電流切換方法，其中該自然週期為該諧振電流的一諧振頻率的倒數，且該諧振頻率的由該變壓器的一漏電感與該電容組的一電容值決定。The zero-current switching method of claim 8, wherein the natural period is an inverse of a resonant frequency of the resonant current, and the resonant frequency is determined by a leakage inductance of the transformer and a capacitance value of the capacitor bank. 如請求項7所述之零電流切換方法，其中在關斷該主開關前的四分之一該自然週期內，導通該第二開關。The zero-current switching method of claim 7, wherein the second switch is turned on within a quarter of the natural period before turning off the main switch. 如請求項7所述之零電流切換方法，其中在關斷該主開關時，同時關斷該第二開關。The zero-current switching method according to claim 7, wherein when the main switch is turned off, the second switch is turned off at the same time. 如請求項7所述之零電流切換方法，其中在到達一工作責任時間時，該初級側電流下降至一零區間，且在該初級側電流為該零區間時，關斷該主開關與該第二開關。The zero-current switching method as claimed in claim 7, wherein when a duty time is reached, the primary-side current drops to a zero interval, and when the primary-side current is in the zero interval, the main switch and the main switch are turned off second switch.
TW110113059A 2020-11-13 2021-04-12 Forward-flyback conversion device with zero current switching and method of zero current switching the same TWI756102B (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
TW109139689 2020-11-13
TW109139689 2020-11-13

Publications (2)

Publication Number Publication Date
TWI756102B true TWI756102B (en) 2022-02-21
TW202220355A TW202220355A (en) 2022-05-16

Family

ID=81329286

Family Applications (1)

Application Number Title Priority Date Filing Date
TW110113059A TWI756102B (en) 2020-11-13 2021-04-12 Forward-flyback conversion device with zero current switching and method of zero current switching the same

Country Status (1)

Country Link
TW (1) TWI756102B (en)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TW201442408A (en) * 2013-04-19 2014-11-01 Univ Nat Kaohsiung Applied Sci Single-stage high power factor flyback-forward converter and light source system
TW201543798A (en) * 2014-05-07 2015-11-16 Lite On Technology Corp Hybrid mode active clamping power transformer
US20160294294A1 (en) * 2015-04-01 2016-10-06 Futurewei Technologies, Inc. Resonant Converters with an Improved Voltage Regulation Range
US20170033701A1 (en) * 2013-01-11 2017-02-02 Futurewei Technologies, Inc. Resonant Converters and Methods
US20180102713A1 (en) * 2013-11-12 2018-04-12 Futurewei Technologies, Inc. Gate Drive Apparatus for Resonant Converters
US20190140639A1 (en) * 2013-02-27 2019-05-09 Hengchun Mao Resonant Power Converters with Switchable Resonant Modes

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170033701A1 (en) * 2013-01-11 2017-02-02 Futurewei Technologies, Inc. Resonant Converters and Methods
US20190140639A1 (en) * 2013-02-27 2019-05-09 Hengchun Mao Resonant Power Converters with Switchable Resonant Modes
TW201442408A (en) * 2013-04-19 2014-11-01 Univ Nat Kaohsiung Applied Sci Single-stage high power factor flyback-forward converter and light source system
US20180102713A1 (en) * 2013-11-12 2018-04-12 Futurewei Technologies, Inc. Gate Drive Apparatus for Resonant Converters
TW201543798A (en) * 2014-05-07 2015-11-16 Lite On Technology Corp Hybrid mode active clamping power transformer
US20160294294A1 (en) * 2015-04-01 2016-10-06 Futurewei Technologies, Inc. Resonant Converters with an Improved Voltage Regulation Range

Also Published As

Publication number Publication date
TW202220355A (en) 2022-05-16

Similar Documents

Publication Publication Date Title
CN106059313B (en) The circuit of reversed excitation and its control method of active clamp
US10637363B2 (en) Converters with hold-up operation
JP5088386B2 (en) Switching power supply
KR101516988B1 (en) Switching power supply device
JP4844674B2 (en) Switching power supply
TWI382642B (en) Resonant circuit with narrow operating frequency band and resonant power converter
JP4238871B2 (en) Switching power supply
KR101304777B1 (en) DC/DC converter with wide input voltage range
CN111669055B (en) Voltage conversion circuit and control method thereof
US20230113753A1 (en) Dc/dc converter and method for controlling output voltage thereof
KR102009351B1 (en) High Efficiency LLC Resonant Converter with Balanced Secondary Currents using the Two Transformer Structure
KR20180004675A (en) Bidirectional Converter with Auxiliary LC Resonant Circuit and Operating Method thereof
CN115378266A (en) Converter suitable for wide-range output voltage and control method thereof
TWI650927B (en) Zero voltage switching flyback converter for primary switch turn-off transitions
CN114583972B (en) Resonant converter, control method and device thereof, and power supply equipment
US11764693B2 (en) Dual-capacitor resonant circuit for use with quasi-resonant zero-current-switching DC-DC converters
KR20140091191A (en) Single Stage AC/DC converter
CN107171563B (en) The combined converter of tight adjustment output
TWI756102B (en) Forward-flyback conversion device with zero current switching and method of zero current switching the same
KR20170059390A (en) Soft-switching full-bridge converter and control method thereof
TWI653813B (en) Forced zero voltage switching flyback converter and using method
CN114679061A (en) Forward-flyback conversion device with zero current switching and switching method thereof
TWI832416B (en) Power converter
KR101721321B1 (en) Hybride type LED Power Supply
TWI818776B (en) Power converter