KR102033478B1 - Active Clamp Forward Converter And Method Of Driving The Same - Google Patents

Abstract

The present invention provides a clamping capacitor and a first inductor connected to a high potential terminal of an input voltage; A first switch connected to the low potential terminal of the input voltage; A second switch connected between the clamping capacitor and the first switch; A second inductor connected between the first inductor and the first switch; A transformer connected to the second inductor in parallel; First to fourth diodes connected to the transformer; First and second output inductors coupled to the transformer; A first output capacitor and a first output resistor connected to the first output inductor and outputting a first output voltage; A third switch and a fifth diode connected to the second output inductor; A multi-output double-ended active clamp forward converter is connected to the fifth diode and includes a second output capacitor and a second output resistor.

Description

Active Clamp Forward Converter And Method Of Driving The Same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active clamp forward converter, and in particular, by configuring the secondary side of the transformer in parallel, the output of the output inductor is reduced and the voltage of the output diode is limited, thereby improving efficiency. It relates to a driving method.

Recently, with the development of vehicle safety and autonomous driving technology, the power required by the vehicle is increasing year by year.

In addition, the development of a mild hybrid vehicle for fuel efficiency improvement is underway due to carbon dioxide emission restrictions.

Accordingly, a vehicle electric system having an output voltage of 48V higher than the existing 14V has been researched and developed. In particular, an output voltage of 14V and a newly required output voltage of a low voltage DC-DC converter (LDC) Attention is drawn to DC-DC converters that simultaneously output 48V.

In addition, as a low voltage DC-DC converter (LDC) that requires high power density, zero voltage switching (ZVS) is possible, and a double-ended active clamp forward converter that reduces the number of switches and the size of the output inductor ( Doubled-ended active clamp forward converter) is widely used, which will be described with reference to the drawings.

1 is a circuit diagram illustrating a conventional multiple output double ended active clamp forward converter, and FIG. 2 is a waveform diagram of a plurality of signals of a conventional multiple output double ended active clamp forward converter.

In FIG. 2, the input voltage Vi is 360V, the first and second output voltages Vo1 and Vo2 are 14V (1.2kW) and 48V (600W), respectively, and the third gate-source voltage Vgs3 and the third voltage. The first and second output inductor currents Ilo1 and Ilo2 are graphs changed at 1/2 magnification for easy understanding.

As shown in FIGS. 1 and 2, the conventional multiple output double-ended active clamp forward converter 10 generates the first and second output voltages Vo1 and Vo2 using the input voltage Vi.

To this end, the multi-output double-ended active clamp forward converter 10 includes the first to third switches S1, S2, and S3, the clamping capacitor Cc, the first and second inductors L1 and L2, and a transformer ( T), first to third diodes D1, D2 and D3, first and second output inductors Lo1 and Lo2, first and second output capacitors Co1 and Co2, and first and second output resistors. (Ro1, Ro2), the first and second switches (S1, S2), the clamping capacitor (Cc), the first and second inductors (L1, L2) constitute the primary side of the transformer (T), First to third diodes D1, D2, and D3, first and second output inductors Lo1 and Lo2, first and second output capacitors Co1 and Co2, and first and second output resistors Ro1, Ro2) and the third switch S3 constitute the secondary side of the transformer T.

The first switch S1, which is the main switch, is connected between the input voltage Vi and the second inductor L2, and according to the first gate-source voltage Vgs1, the input voltage Vi and the second inductor L2. The first switch current Is1 flows through the channel of the first switch S1 to which the first drain-source voltage Vds1 is applied.

Here, the first drain-source voltage Vds1 of the first switch S1 in the turn-off state is clamped to the sum Vds1 to (Vi + Vc) of the input voltage Vi and the capacitor voltage Vc. )do.

The second switch S2, which is an auxiliary switch, is connected between the clamping capacitor Cc and the second inductor L2, and according to the second gate-source voltage Vgs2, the clamping capacitor Cc and the second inductor L2. The second switch current Is2 flows through the channel of the second switch S2 to which the second drain-source voltage Vds2 is applied.

The clamping capacitor Cc is connected between the first inductor L1 and the second switch S2, stores the inductor energy of the first inductor L1 as the capacitor voltage Vc, and stores the stored capacitor voltage Vc. And outputs clamping energy corresponding to the second inductor L2.

The first inductor L1, which is a leakage inductor, is connected between the input voltage Vi and the clamping capacitor Cc and the second inductor L2. The first inductor L1 is connected to one end of the primary side of the transformer T so as to be connected to the transformer T. Leakage Stores or outputs leakage energy due to magnetic flux.

The second inductor L2, which is a magnetization inductor, is connected between the first and second switches S1 and S2 and the first inductor L1, and is connected to both ends of the primary side of the transformer T to connect the first inductor L1. Stores or outputs magnetization energy according to mutual magnetic flux.

The transformer T is connected between the second inductor L2 and the first and second diodes D1 and D2, and the transformer T has different leakage energy and magnetization energy stored in the first and second inductors L1 and L2. Convert it to voltage and output it.

The first and second diodes D1 and D2 are connected to both ends of the secondary side of the transformer T, respectively, and rectify the transformer voltage output from the transformer T. The first and second diodes D1 are connected to each other. , D2) flows first and second diode currents Id1 and Id2, respectively.

One end of the first output inductor Lo1 is connected to the negative terminals of the first and second diodes D1 and D2, and the first output capacitor Co1 and the first output resistor Ro1 are connected to the first output inductor Lo1. Is connected between the other end of the and the secondary neutral point of the transformer (T), the first output inductor (Lo1), the first output capacitor (Co1) and the first output resistor (Ro1) outputs the first output voltage (Vo1). do.

One end of the second output inductor Lo2 is connected to the other end of the first output inductor Lo1, the third diode D3 is connected to the other end of the second output inductor Lo2, and the second output capacitor Co2 And a second output resistor Ro2 is connected to the other end of the second output inductor Lo2, wherein the second output inductor Lo2, the second output capacitor Co2, and the second output resistor Ro2 are connected to the second output voltage. Outputs (Vo2).

The third switch S3 is connected between the other end of the second output inductor Lo2 and the neutral side of the secondary side of the transformer T, and according to the third gate-source voltage Vgs3, the second output inductor Lo2 and the transformer The third switch current Is3 flows through the channel of the third switch S3 to which the third drain-source voltage Vds3 is applied, while switching the electrical connection of the neutral side of the secondary side T.

In this conventional multiple output double ended active clamp forward converter 10, a first switch S1 is turned on and a second switch S2 is turned off. During the time period TP1, the primary side of the transformer T forms a current path leading to the input voltage Vi, the transformer T, and the first switch S1 so that the first and second inductors L1, L2. The first and second inductor currents Il1 and Il2 increase, and the secondary side of the transformer T operates in a powering mode in which the first diode current Id1 flows through the first diode D1. .

In addition, during the second time interval TP2 when the first switch S1 is turned off and the second switch S2 is turned on, the primary side of the transformer T is the capacitor voltage Vc and the transformer T. ), A current path leading to the second switch S2 is formed so that the first and second inductor currents Il and Il2 of the first and second inductors L1 and L2 decrease, and the transformer T resets. After the reset, the secondary side of the transformer T operates in a powering mode in which the second diode current Id2 flows through the second diode D2.

In addition, during the third time interval TP3 when the third switch S3 is turned on, the second output inductor Lo2 on the secondary side of the transformer T is built up, and the third During the fourth time interval TP4 when the switch S3 is turned off, the secondary side of the transformer T operates in a powering mode in which the third diode current Id3 flows through the third diode D3.

However, in the conventional multi-output double-ended active clamp forward converter 10, since the second output voltage Vo2 is outputted through the first output voltage Vo1, the first output inductor current of the first output inductor Lo1. Ilo1 is the sum of the first and second load currents of the first and second output resistors Ro1 and Ro2, and as a result, the burden of the first output inductor Lo1 is affected by the second output voltage Vo2. There is a growing problem.

In addition, the first and second diode voltages Vd1 and Vd2 of the first and second diodes D1 and D2 may have voltages at both ends of the primary inductor L2 of the transformer T and the winding ratio of the transformer T. In the first and second diodes D1 and D2, resonance occurs largely due to the presence of parasitic capacitors. As a result, the first and second diode voltages of the first and second diodes D1 and D2 are increased. There is a problem in that the voltage stress of the first and second diodes D1 and D2 is increased due to an increase in Vd1 and Vd2.

The present invention has been made to solve the above problems, by configuring the first and second output inductors on the secondary side of the transformer in parallel, the current of the first output inductor is reduced to reduce the overhead of the first output inductor An object of the present invention is to provide a multi-output double-ended active clamp forward converter with improved efficiency and a driving method thereof.

In addition, the present invention connects the third and fourth diodes, which are clamping diodes, to the first and second diodes on the secondary side of the transformer, respectively, thereby limiting the voltages of the first and second diodes. Another object of the present invention is to provide a multi-output double-ended active clamp forward converter and a method of driving the same, which reduce voltage stress and improve efficiency.

In order to achieve the above object, the present invention, the clamping capacitor and the first inductor connected to the high potential terminal of the input voltage; A first switch connected to the low potential terminal of the input voltage; A second switch connected between the clamping capacitor and the first switch; A second inductor connected between the first inductor and the first switch; A transformer connected to the second inductor in parallel; First to fourth diodes connected to the transformer; First and second output inductors coupled to the transformer; A first output capacitor and a first output resistor connected to the first output inductor and outputting a first output voltage; A third switch and a fifth diode connected to the second output inductor; A multi-output double-ended active clamp forward converter is connected to the fifth diode and includes a second output capacitor and a second output resistor.

The first and second output inductors may be connected in parallel to the neutral point of the transformer.

In addition, the third and fourth diodes may be connected to the first and second diodes, respectively, to limit the voltage of the negative terminal of the first and second diodes to be equal to or less than the second output voltage.

The anode terminals of the first and second diodes include the first output capacitor and the second terminal of the first output resistor, the source of the third switch, the second output capacitor and the second terminal of the second output resistor. A cathode terminal of the first diode and an anode terminal of the third diode are connected to a second output terminal of the transformer, and a cathode terminal of the second diode and an anode terminal of the fourth diode are connected to the first terminal of the transformer. The negative terminal of the third and fourth diodes may be connected to an output terminal, and the negative terminal of the fifth diode, the second output capacitor, and the first terminal of the second output resistor.

In addition, a first terminal of the first output inductor is connected to the neutral point of the transformer, a second terminal of the first output inductor is connected to the first terminal of the first output capacitor and the first output resistor, The second terminal of the second output inductor is connected to the neutral point of the transformer, the second terminal of the second output inductor is connected to the positive terminal of the drain and the fifth diode of the third switch, The negative electrode terminal may be connected to the second output capacitor and the first terminal of the second output resistor.

The first switch switches the electrical connection between the input voltage and the second inductor according to a first gate-source voltage, and the second switch includes the clamping capacitor and the second gate-source voltage. The electrical connection of the second inductor is switched, and the third switch may switch the electrical connection of the second output inductor and the first and second diodes according to a third gate-source voltage.

On the other hand, the present invention, the first to third switches, clamping capacitors, first and second inductors, transformers, first to fifth diodes, first and second output inductors, first and second output capacitors, the first And a second output resistor, wherein the multiple output double-ended active clamp forward converter includes: turning on the first and second switches during the first time period; turn-off to form a current path leading to an input voltage, said transformer, and said first switch; During the second time period, turning off and on the first and second switches, respectively, to form a current path leading to the capacitor voltage of the clamping capacitor, the transformer, and the second switch; During the third time period overlapping the entire first time period and overlapping a portion of the tip of the second time period, the third switch is turned on, so that the transformer, the second output inductor, the third switch, Forming a current path leading to the first and second diodes; During the fourth time period overlapping a part of the rear end of the fourth time period, the third switch is turned off, so that the transformer, the second output inductor, the fifth diode, the second output capacitor and the second A method of driving a multi-output double-ended active clamp forward converter comprising forming an output resistance and a current path leading to the first and second diodes.

The present invention has the effect that by configuring the first and second output inductors on the secondary side of the transformer in parallel, the current of the first output inductor is reduced to reduce the overhead of the first output inductor and improve the efficiency.

In addition, the present invention connects the third and fourth diodes, which are clamping diodes, to the first and second diodes on the secondary side of the transformer, respectively, thereby limiting the voltages of the first and second diodes. The voltage stress is reduced and the efficiency is improved.

1 is a circuit diagram illustrating a conventional multiple output double ended active clamp forward converter.
2 is a waveform diagram of multiple signals of a conventional multiple output double ended active clamp forward converter.
3 is a circuit diagram illustrating a multiple output double ended active clamp forward converter in accordance with an embodiment of the present invention.
4 is a waveform diagram of multiple signals of a multiple output double ended active clamp forward converter in accordance with an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a circuit diagram illustrating a multiple output double ended active clamp forward converter according to an embodiment of the present invention.

As shown in FIG. 3, the multiple output double ended active clamp forward converter 110 according to an embodiment of the present invention generates the first and second output voltages Vo1 and Vo2 using the input voltage Vi. .

To this end, the multi-output double-ended active clamp forward converter 110 includes the first to third switches S1, S2, and S3, the clamping capacitor Cc, the first and second inductors L1 and L2, and a transformer ( T), first to fifth diodes D1, D2, D3, D4, D5, first and second output inductors Lo1, Lo2, first and second output capacitors Co1, Co2, first and second The second output resistor (Ro1, Ro2), the first and second switches (S1, S2), the clamping capacitor (Cc), the first and second inductors (L1, L2) are the primary side of the transformer (T) The first to fifth diodes (D1, D2, D3, D4, D5), the first and second output inductors (Lo1, Lo2), the first and second output capacitors (Co1, Co2), the first And the second output resistors Ro1 and Ro2 and the third switch S3 constitute the secondary side of the transformer T.

The first to third switches S1, S2, and S3 may be transistors.

The first switch S1, which is the main switch, is connected between the input voltage Vi and the second inductor L2, and according to the first gate-source voltage Vgs1, the input voltage Vi and the second inductor L2. The first switch current Is1 flows through the channel of the first switch S1 to which the first drain-source voltage Vds1 is applied.

For example, when the first switch S1 is a negative N type transistor, the gate of the first switch S1 is connected to the first gate-source voltage Vgs1 and the source of the first switch S1 is used. Is connected to the low potential terminal of the input voltage (Vi), the drain of the first switch (S1) is the source of the second switch (S2), the second terminal of the second inductor (L2), the second of the transformer (T) It is connected to the input terminal.

Here, the first drain-source voltage Vds1 of the first switch S1 in the turn-off state is clamped to the sum Vds1 to (Vi + Vc) of the input voltage Vi and the capacitor voltage Vc. )do.

The second switch S2, which is an auxiliary switch, is connected between the clamping capacitor Cc and the second inductor L2, and according to the second gate-source voltage Vgs2, the clamping capacitor Cc and the second inductor L2. The second switch current Is2 flows through the channel of the second switch S2 to which the second drain-source voltage Vds2 is applied.

For example, when the second switch S2 is a negative N type transistor, the gate of the second switch S2 is connected to the second gate-source voltage Vgs2 and the source of the second switch S2 is connected. Is connected to the drain of the first switch (S1), the second terminal of the second inductor (L2), the second input terminal of the transformer (T), the drain of the second switch (S2) of the clamping capacitor (Cc) It is connected to two terminals.

The clamping capacitor Cc is connected between the first inductor L1 and the second switch S2, stores the inductor energy of the first inductor L1 as the capacitor voltage Vc, and stores the stored capacitor voltage Vc. And outputs clamping energy corresponding to the second inductor L2.

For example, the first terminal of the clamping capacitor Cc is connected to the high potential terminal of the input voltage Vi, the first terminal of the first inductor L1, and the second terminal of the clamping capacitor Cc is the second terminal. It is connected to the drain of the switch S2.

The first inductor L1, which is a leakage inductor, is connected between the input voltage Vi and the clamping capacitor Cc and the second inductor L2. The first inductor L1 is connected to one end of the primary side of the transformer T so as to be connected to the transformer T. Leakage Stores or outputs leakage energy due to magnetic flux.

For example, a first terminal of the first inductor L1 is connected to a first terminal of the clamping capacitor Cc, a second terminal of the first inductor L1 is a first terminal of the second inductor L2, It is connected to the first input terminal of the transformer (T).

The second inductor L2, which is a magnetization inductor, is connected between the first and second switches S1 and S2 and the first inductor L1, and is connected to both ends of the primary side of the transformer T to connect the first inductor L1. Stores or outputs magnetization energy according to mutual magnetic flux.

For example, the first terminal of the second inductor L2 is connected to the second terminal of the first inductor L1, the first input terminal of the transformer T, and the second terminal of the second inductor L2 is connected. It is connected to the drain of the first switch (S1), the source of the second switch (S2), the second input terminal of the transformer (T).

The transformer T is connected between the second inductor L2 and the first to fourth diodes D1, D2, D3, and D4, and the leakage energy and magnetization stored in the first and second inductors L1 and L2. The energy is converted into different transformer voltages and output.

For example, the first input terminal of the transformer T is connected to the second terminal of the first inductor L1, the first terminal of the second inductor L2, and the second input terminal of the transformer T The second terminal of the second inductor (L2), the drain of the first switch (S1), the source of the second switch (S2), the first output terminal of the transformer (T) and the negative terminal of the second diode (D2) and Connected to the positive terminal of the fourth diode D4, the second output terminal of the transformer T is connected to the negative terminal of the first diode D1 and the positive terminal of the third diode D3, and The neutral point is connected to the first terminals of the first and second output inductors Lo1 and Lo2.

The first and third diodes D1 and D3 connected in series with each other are connected to one end of the secondary side of the transformer T, and the second and fourth diodes D2 and D4 connected in series with each other are the transformer T. The first to fourth diodes D1, D2, D3, and D4 are connected to the other ends of the second side of the rectifier to rectify the transformer voltage output from the transformer T. The first to fourth diodes D1 and D2 are rectified. The first through fourth diode currents Id1, Id2, Id3, and Id4 flow through D3 and D4, respectively.

For example, the positive terminals of the first and second diodes D1 and D2 may include a second terminal of the first output capacitor Co1, a second terminal of the first output resistor Ro1, and a source of the third switch S3. And a second terminal of the second output capacitor Co2 and a second terminal of the second output resistor Ro2, and the negative terminal of the first diode D1 and the positive terminal of the third diode D3 are transformers (T). Is connected to the second output terminal of the second terminal (D2), the cathode terminal of the second diode (D2) and the positive terminal of the fourth diode (D4) is connected to the first output terminal of the transformer (T), the third and fourth diode (D3) , The negative terminal of D4 is connected to the negative terminal of the fifth diode D5, the second output capacitor Co2 and the first terminal of the second output resistor Ro2.

One end of the first output inductor Lo1 is connected to the neutral side of the secondary side of the transformer T, and the first output capacitor Co1 and the first output resistor Ro1 are connected to the other end and the first end of the first output inductor Lo1. And a positive terminal of the second diodes D1 and D2, wherein the first output inductor Lo1, the first output capacitor Co1, and the first output resistor Ro1 output the first output voltage Vo1. do.

For example, the first terminal of the first output inductor Lo is connected to the neutral terminal of the secondary side of the transformer T, the first terminal of the second output inductor Lo2, and the second terminal of the first output inductor Lo1. The terminal is connected to the first terminal of the first output capacitor Co1 and the first output resistor Ro1, and the second terminal of the first output capacitor Co1 and the first output resistor Ro1 is first and second. The first terminal of the diodes D1 and D2, the drain of the third switch S3, the second output capacitor Co2 and the second terminal of the second output resistor Ro2 are connected to each other. It is output between the first output capacitor Co1 and the first and second terminals of the first output resistor Ro1.

One end of the second output inductor (Lo2) is connected to the neutral side of the secondary side of the transformer (T), the positive terminal of the fifth diode (D5) is connected to the other end of the second output inductor (Lo2), the fifth diode (D5) The negative terminal of is connected to the negative terminal of the third and fourth diodes (D3, D4), the second output capacitor (Co2) and the second output resistor (Ro2) is connected to the other end of the second output inductor (Lo2). The second output inductor Lo2, the second output capacitor Co2, and the second output resistor Ro2 output the second output voltage Vo2.

For example, the first terminal of the second output inductor Lo2 is connected to the neutral point of the secondary side of the transformer T, the first terminal of the first output inductor Lo1, and the second terminal of the second output inductor Lo2. The terminal is connected to the drain of the third switch S3 and the positive terminal of the fifth diode D5, and the negative terminal of the fifth diode D5 is connected to the second output capacitor Co2 and the second output resistor Ro2. It is connected to the first terminal, the second terminal of the second output capacitor (Co1) and the second output resistor (Ro2), the positive terminal of the first and second diodes (D1, D2), the first output capacitor (Co1) and The second terminal of the first output resistor Ro1 is connected to the source of the third switch S3, and the second output voltage Vo2 is the first of the second output capacitor Co2 and the second output resistor Ro2. And a second terminal.

The third switch S3 is connected between the other end of the second output inductor Lo2 and the positive terminal of the first and second diodes D1 and D2 and according to the third gate-source voltage Vgs3. The third switch current Is3 is switched to the channel of the third switch S3 to which the inductor Lo2 and the first and second diodes D1 and D2 are switched, and to which the third drain-source voltage Vds3 is applied. ) Flows.

For example, when the third switch S3 is a negative N type transistor, the gate of the third switch S3 is connected to the third gate-source voltage Vgs3 and the source of the third switch S3 is used. Is the positive terminal of the first and second diodes D1 and D2, the second terminal of the first output capacitor Co1 and the first output resistor Ro1, the second output capacitor Co2 and the second output resistor Ro2. ) Is connected to the second terminal of the second switch (S3), the drain of the third switch (S3) is connected to the second terminal of the second output inductor (Lo2), the positive terminal of the fifth diode (D5).

In the multiple output double ended active clamp forward converter 110 according to the embodiment of the present invention, the first and second output inductors Lo1 and Lo2 on the secondary side of the transformer T are configured in parallel, and the first and second The second output voltages Vo1 and Vo2 are independently output through the first and second output inductors Lo1 and Lo2, respectively.

Specifically, the first output voltage Vo1 is determined by the duty ratio of the first and second switches S1 and S2, and the second output voltage Vo2 is determined by using the third switch S3. As a result, the second output inductor Lo2 may be built up to have a value greater than a voltage between both ends of the secondary side of the transformer T.

As such, since the first and second output voltages Vo1 and Vo2 are independently output from each other, the first output inductor current Ilo1 of the first output inductor Lo1 is the second of the second output resistor Ro2. It becomes the first load current of the first output resistance Ro1 independent of the load current, and as a result, the first output inductor current Ilo1 of the first output inductor Lo1 is reduced, so that the burden of the first output inductor Lo1 is reduced. This reduces the power consumption generated in the first output inductor Lo1 and improves the saturation problem of the first output inductor Lo1.

The first and second diodes D3 and D4, which are clamping diodes, are connected to the first and second diodes D1 and D2 on the secondary side of the transformer T, respectively. When the voltage at the second output terminal (ie, the voltage at the negative terminals of the first and second diodes D1 and D2) exceeds the second output voltage Vo2, the third and fourth diodes D3 and D4 are turned on. Can be turned on.

Accordingly, the voltages of the negative terminals of the first and second diodes D1 and D2 may be clamped to the second output voltage Vo2 or less by the third and fourth diodes D3 and D4. As a result, the first and second diode voltages Vd1 and Vd2 of the first and second diodes D1 and D2 are reduced to reduce the voltage stress of the first and second diodes D1 and D2 and to reduce the converter. The efficiency of 110 can be improved.

In the multiple output double-ended active clamp forward converter 110 according to the exemplary embodiment of the present invention, the first switch S1 is turned on and the second switch S2 is turned off. the first time period (TP1 in FIG. 4) that is off), and the second time period (TP2 in FIG. 4), in which the first switch S1 is turned off and the second switch S2 is turned on, The third time period (TP3 of FIG. 4) when the switch S3 is turned on, and the fourth time period (TP4 of FIG. 4) when the third switch S3 is turned off, is driven and is a constant DC voltage. The first and second output voltages Vo1 and Vo2 are output, which will be described with reference to the drawings.

4 is a waveform diagram of a plurality of signals of a multiple output double-ended active clamp forward converter according to an embodiment of the present invention, which will be described with reference to FIG. 3.

In FIG. 4, the input voltage Vi is 360V, the first and second output voltages Vo1 and Vo2 are 14V (1.2kW) and 48V (600W), respectively, and the third gate-source voltage Vgs3 and the third voltage. The first and second output inductor currents Ilo1 and Ilo2 are graphs changed at 1/2 magnification for easy understanding.

 As shown in FIG. 4, during the first time period TP1 of the multi-output double-ended active clamp forward converter 110 according to the embodiment of the present invention, the first gate-source voltage Vgs1 becomes high level. The first switch S1 is turned on, the second gate-source voltage Vgs2 is turned low, and the second switch S2 is turned off.

That is, in the first switch S1 in the turn-on state, the first drain-source voltage Vds1 becomes low level and the first switch current Is1 of the channel becomes high level (current flow), and is turned off. In the second switch S2 in the state, the second drain-source voltage Vds2 becomes high level and the second switch current Is2 of the channel becomes low level (current cutoff).

Accordingly, the primary side of the transformer T forms a current path that leads to the input voltage Vi, the transformer T, and the first switch S1 so that the first and second inductors L1 and L2 of the first and second inductors L1 and L2 are formed. The second inductor current Il1, Il2 gradually increases, and the first output inductor Lo1 on the secondary side of the transformer T is powered by the first diode current Id1 flowing through the first diode D1. ) Mode.

For example, the first gate-source voltage Vgs1 and the first drain-source voltage Vds1 are voltages that allow the first switch S1 to be completely turned on, respectively, and the second gate-source voltage. Vgs2 and the second drain-source voltage Vds2 are about 0V and about 580V, respectively, and the second switch S2 is completely turned off, and the first inductor current Il1 is about 10A to about 20A. The second inductor current Il2 may increase from about 0A to about 12A.

The first diode voltage Vd1 is about 0V, the average value of the second diode voltage Vd2 is about 40V, the first diode current Id1 increases from about 110A to about 150A, and the second diode current ( Id2) is about 0A, and the first output inductor current Ilo1 may increase from about 80A to about 100A.

In addition, during the second time period TP1 of the multi-output double-ended active clamp forward converter 110 according to the exemplary embodiment of the present invention, the first gate-source voltage Vgs1 becomes low level so that the first switch S1 is turned on. Is turned off, and the second gate-source voltage Vgs2 becomes high level, so that the second switch S2 is turned on.

That is, in the first switch S1 in the turn-off state, the first drain-source voltage Vds1 becomes high level and the first switch current Is1 of the channel becomes low level (current cutoff). In the second switch S2 in the state, the second drain-source voltage Vds2 becomes low level and the second switch current Is2 of the channel becomes high level (current flow).

Accordingly, the primary side of the transformer T forms a current path that leads to the capacitor voltage Vc, the transformer T, and the second switch S2 so that the first and second inductors L1 and L2 of the first and second inductors L1 and L2 are formed. The second inductor current Il1, Il2 gradually decreases, the transformer T is reset, and the secondary side of the transformer T has power through which the second diode current Id2 flows through the second diode D2. Operate in ring mode.

For example, the first gate-source voltage Vgs1 and the first drain-source voltage Vds1 are about 0V and about 580V, respectively, and the first switch S1 is completely turned off and the second gate- The source voltage Vgs2 and the second drain-source voltage Vds2 are voltages which allow the second switch S2 to be completely turned on, respectively, and the first inductor current Il1 is about -5A to about 5A. And the second inductor current Il2 may decrease from about 12A to about 0A.

The average value of the first diode voltage Vd1 is about 25V, the second diode voltage Vd2 is about 0V, the first diode current Id1 is about 0A, and the second diode current Id2 is about 150A. At about 110A and the first output inductor current (Ilo1) can be reduced from about 100A to about 80A.

On the other hand, during the third time period TP3 of the multiple output double-ended active clamp forward converter 110 according to the embodiment of the present invention, the third gate-source voltage Vgs3 becomes high level so that the third switch S3 Is turned on.

That is, in the third switch S3 in the turn-on state, the third drain-source voltage Vds3 becomes low level and the third switch current Is3 of the channel becomes high level (current flow).

Accordingly, the secondary side of the transformer T forms a current path leading to the transformer T, the second output inductor Lo2, the third switch S3, and the first and second diodes D1 and D2. The second output inductor Lo2 on the secondary side of (T) is build-up.

For example, the third gate-source voltage Vgs3 is a voltage that causes the third switch S3 to be turned on completely, and the third switch current Is3 increases from about 40A to about 45A, The fifth diode current Id5 may be about 0A, and the second output inductor current Ilo2 may increase from about 40A to about 44A.

In addition, during the fourth time period TP4 of the multi-output double-ended active clamp forward converter 110 according to the exemplary embodiment of the present invention, the third gate-source voltage Vgs3 becomes low level so that the third switch S3 is turned on. Is turned on.

That is, in the third switch S3 in the turn-off state, the third drain-source voltage Vds3 becomes high level and the third switch current Is3 of the channel becomes low level (current cutoff).

Accordingly, the secondary side of the transformer T may include the transformer T, the second output inductor Lo2, the fifth diode D5, the second output capacitor Co2, and the second output resistor Ro2, the first and the like. The second output inductor Lo2 on the secondary side of the transformer T forms a current path leading to the second diodes D1 and D2 so that a fifth diode current Id5 flows through the fifth diode D5. It works.

For example, the third gate-source voltage Vgs3 is about 0V, the third switch S3 is completely turned off, the third switch current Is3 is 0A, and the fifth diode current Id5. May decrease from about 45A to about 40A, and the second output inductor current Ilo2 may decrease from about 44A to about 40A.

Here, the first time section TP1 overlaps a part of the tip of the third time section TP3, and the second time section TP2 overlaps the entire fourth time section TP4 and the third time section TP3. The third time period TP3 overlaps with the entire first time period TP1, overlaps with a portion of the front end of the second time period TP2, and the fourth time period TP4 overlaps the second end of the second time period TP4. It overlaps with a part of the rear end of the time section TP2.

As described above, in the multiple output double-ended active clamp forward converter 110 according to the embodiment of the present invention, the first and second output inductors Lo1 and Lo2 on the secondary side of the transformer T configured in parallel are formed. Since the first and second output voltages Vo1 and Vo2 are output independently of each other, the first output inductor current Ilo1 of the first output inductor Lo1 is independent of the second load current of the second output resistor Ro2. The first load current of the first output resistor Ro1 becomes a result, and as a result, the first output inductor current Ilo1 of the first output inductor Lo1 is the entire time interval (first and second time intervals TP1 and TP2). Or from about 80 A to about 100 A during the third and fourth time periods (TP3, TP4).

That is, the first output inductor current Ilo1 of the first output inductor Lo1 of the present invention is the first output inductor current (Ilo1 of FIG. 2) of the conventional first output inductor Lo1 (about 130A to about 150A). By maintaining a smaller value, the burden on the first output inductor Lo1 is reduced, the power consumption generated in the first output inductor Lo1 is reduced, and the saturation problem of the first output inductor Lo1 is improved.

In addition, voltages of the first and second output terminals of the transformer T (that is, the cathode terminals of the first and second diodes D1 and D2) are controlled by the third and fourth diodes D3 and D4, which are clamping diodes. Voltage) is limited, so that the voltages of the negative terminals of the first and second diodes D1 and D2 are respectively increased during the first and second time periods TP1 and TP2 or during the third and fourth time periods TP3 and TP4, respectively. Maintained below about 50V.

That is, the voltages of the negative electrode terminals of the first and second diodes D1 and D2 of the present invention are smaller than the voltage of the negative electrode terminal of the conventional second diode D2 (Vd2 of FIG. 2) (about 80 V or less). The voltage stress of the first and second diodes D1 and D2 is reduced and the efficiency of the converter 110 is improved.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art various modifications and changes of the present invention without departing from the spirit and scope of the present invention described in the claims below I can understand that you can.

110: Multiple Output Double Ended Active Clamp Forward Converter
Vi: input voltage Vo1, Vo2: first and second output voltages
S1 to S3: first to third switches
Cc: clamping capacitor L1, L2: first and second inductors
T: transformers D1 to D5: first to fifth diodes
Lo1, Lo2: first and second output inductors
Co1, Co2: first and second output capacitor
Ro1, Ro2: first and second output resistors

Claims (7)

A clamping capacitor and a first inductor connected to the high potential terminal of the input voltage;
A first switch connected to the low potential terminal of the input voltage;
A second switch connected between the clamping capacitor and the first switch;
A second inductor connected between the first inductor and the first switch;
A transformer connected to the second inductor in parallel;
First to fourth diodes connected to the transformer;
First and second output inductors coupled to the transformer;
A first output capacitor and a first output resistor connected to the first output inductor and outputting a first output voltage;
A third switch and a fifth diode connected to the second output inductor;
A second output capacitor and a second output resistor connected to the fifth diode and outputting a second output voltage
Multiple output double ended active clamp forward converter comprising a.
The method of claim 1,
And the first and second output inductors are connected in parallel to the neutral point of the transformer.
The method of claim 1,
The third and fourth diodes are connected to the first and second diodes, respectively, to limit the voltages of the negative terminals of the first and second diodes to the output voltage below the second output voltage. .
The method of claim 1,
Positive terminals of the first and second diodes are connected to the first output capacitor and the second terminal of the first output resistor, the source of the third switch, the second output capacitor, and the second terminal of the second output resistor. Become,
The negative terminal of the first diode and the positive terminal of the third diode are connected to the second output terminal of the transformer,
The negative terminal of the second diode and the positive terminal of the fourth diode is connected to the first output terminal of the transformer,
The negative terminal of the third and fourth diodes is a multiple output double-ended active clamp forward converter connected to the negative terminal of the fifth diode, the second output capacitor and the first terminal of the second output resistor.
The method of claim 4, wherein
The first terminal of the first output inductor is connected to the neutral point of the transformer, the second terminal of the first output inductor is connected to the first terminal of the first output capacitor and the first output resistor,
The second terminal of the second output inductor is connected to the neutral point of the transformer, the second terminal of the second output inductor is connected to the drain terminal of the third switch and the positive terminal of the fifth diode,
And a cathode terminal of the fifth diode is connected to the second output capacitor and the first terminal of the second output resistor.
The method of claim 1,
The first switch switches an electrical connection between the input voltage and the second inductor according to a first gate-source voltage.
The second switch switches an electrical connection between the clamping capacitor and the second inductor according to a second gate-source voltage.
And the third switch switches an electrical connection between the second output inductor and the first and second diodes in accordance with a third gate-source voltage.
First to third switches, clamping capacitors, first and second inductors, transformers, first to fifth diodes, first and second output inductors, first and second output capacitors, and first and second output resistors. In the driving method of a multiple output double-ended active clamp forward converter comprising:
During the first time period, the first and second switches are turned on and off, respectively, to form an input voltage, the transformer, and a current path leading to the first switch. Making a step;
During the second time period, turning off and on the first and second switches, respectively, to form a current path leading to the capacitor voltage of the clamping capacitor, the transformer, and the second switch;
During the third time period overlapping the entire first time period and overlapping a portion of the tip of the second time period, the third switch is turned on, so that the transformer, the second output inductor, the third switch, Forming a current path leading to the first and second diodes;
During the fourth time period overlapping with a part of the rear end of the second time period, the third switch is turned off, so that the transformer, the second output inductor, the fifth diode, the second output capacitor and the second Forming an output resistance and a current path leading to the first and second diodes
Method of driving a multi-output double-ended active clamp forward converter comprising a.

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