TWI521851B - Hybrid mode active clamping power transformer - Google Patents

Description

Mixed mode active clamp power converter

The present invention relates to a power converter, and more particularly to a hybrid mode active clamp power converter.

With the advancement of modern technology and the booming of portable electronic products, the performance and applications of switching converters have received increasing attention. In recent years, due to the great advancement of power electronics technology and the development of nanotechnology, electronic equipment has become increasingly thin and light, energy-saving, and cost-reducing. The internal power converters also need to be light, short, and energy-saving. Trend design for increasing power and reducing production costs. The power supply is an electronic device necessary for most electronic products to convert the battery or mains input power into a special specification output power required for electronic products. With the evolution of technology, the conversion efficiency of power supplies is constantly being asked to a better level. Conversion efficiency is defined as the ratio of the output power of the output power supply to the input power of the input power supply.

A power conversion system receives an input direct current (DC) or alternating current (AC) power and converts it to a DC or AC output power, which typically exhibits a voltage different from the input power. The control of the output power may correspond to the output voltage or the output current. A boost converter (also known as a step-up converter) is a power converter having an output voltage greater than its input voltage. It is an at least one first electronically controlled switch (eg, a transistor), at least a first energy storage component (eg, an electrical coil), and an additional component (eg, a diode or a second electronically controlled switch) Switching Mode power supply. Typically, the electronically controlled switches and the two-pole system are disposed between the electrical coil and the output, wherein current is alternately drawn to charge the electrical coil to return to the first electronically controlled switch that should be turned off, and to be transmitted To a load, to return to the first electronically controlled switch that should be turned on. When the current is delivered to the load, the current passes through the diode or the second electronically controlled switch. A buck converter (also known as a step-down converter) is a power converter having an output voltage that is less than its input voltage. It is a type comprising at least a third electronically controlled switch (eg, a transistor), at least a second energy storage component (eg, an electrical coil), and an additional component (eg, a diode or a fourth electronic control) Switch mode power supply for switch). Generally, the electronically controlled switch and the two-pole system are disposed between the input power source and the electric coil, wherein current is alternately drawn to charge the electric coil via a load to return to the third electronically controlled switch that should be turned off. And continuously energizing the electrical coil toward the load to return to the third electronically controlled switch that should be opened. The diode or fourth electrically controlled open relationship is in series with the electrical coil when the electrical coil is energized toward the load. A flyback converter is a converter having an output voltage that can be greater or less than its input voltage. It is a switched mode power supply comprising: at least one electronically controlled switch; an energy storage component comprising at least one electrical coil (particularly a transformer) whereby the voltage ratio is increased with the added advantage of isolation; and at least An additional component (eg, a diode and/or an additional electronically controlled switch). Typically, a primary electrical coil of the transformer is coupled between the electronically controlled switch and the input voltage and a secondary electrical coil of the transformer is coupled between the additional component and the output. The power converters listed above represent some description of the topology, but are not meant to be limiting.

In low-power applications, flyback converters are currently widely used power circuits, but flyback converters suffer from electromagnetic interference from input current pulses and voltage surges caused by leakage inductance. Furthermore, the conventional active clamp SEPIC is difficult to achieve zero voltage switching in the full load range, so that the efficiency cannot be greatly improved.

Embodiments of the present invention provide a hybrid mode active clamp power converter, the hybrid mode active clamp power converter includes an input inductor, a lower bridge switch, an upper bridge switch, a first storage capacitor, a clamp capacitor, a resonant inductor, and a magnetizing inductor. , transformer, output diode and output capacitor. The first end of the input inductor is coupled to the positive terminal of the input voltage source, wherein the input voltage source operates between the first voltage and the second voltage. The control terminal of the lower bridge switch receives the first control signal, and the first end of the lower bridge switch is connected to the negative terminal of the input voltage source. The control end of the upper bridge switch receives the second control signal, and the first end of the upper bridge switch is connected to the second end of the lower bridge switch. The first end of the first storage capacitor is connected to the first end of the lower bridge switch. The first end of the clamp capacitor is connected to the second end of the upper bridge switch, and the second end of the clamp capacitor is connected to the second end of the first storage capacitor. The first end of the resonant inductor is coupled to the second end of the lower bridge switch. The first end of the magnetizing inductance is connected to the resonant inductor, and the second end of the exciting inductor is connected to the second end of the clamping capacitor. The transformer has a primary side inductance and a secondary side inductance, and the primary side inductance is connected in parallel with the excitation inductance, wherein the primary side inductance and the secondary side inductance have a mutual inductance effect. The anode of the output diode is connected to the first end of the secondary side inductor. The first end of the output capacitor is connected to the cathode of the output diode, and the second end of the output capacitor is connected to the second end of the secondary side inductor. The input inductor has a boundary inductance value and the boundary inductance value is set according to the first voltage and the heavy load as an initial condition of the hybrid mode active clamp power converter, so that when the lower bridge switch is turned on, the input inductor current will input the inductor Charging is performed, and the first switching current flowing through the lower bridge switch is equal to the sum of the input inductor current and the exciting inductor current to achieve zero voltage switching. When the input voltage source operates at the first voltage, the input inductor operates in the boundary conduction mode and causes the hybrid mode active clamp power converter to achieve zero voltage switching.

In one embodiment of the present invention, when the input voltage source operates at a greater than the first voltage, the input inductor current operates in a discontinuous conduction mode and generates a negative current such that the body diode of the lower bridge switch is easily turned on and The hybrid mode is actively clamped to the power converter for zero voltage switching.

In one of the embodiments of the present invention, the hybrid mode active clamp power converter achieves zero voltage switching to improve power conversion efficiency by operating the input inductor current in a boundary conduction mode or a discontinuous conduction mode.

In one embodiment of the invention, the magnetizing inductor current charges the parasitic capacitance of the lower bridge switch when the upper bridge switch is non-conducting and the input inductor current is zero.

In one embodiment of the present invention, when the voltage across the first end and the second end of the lower bridge switch is zero, the magnetizing inductor current flows through the body diode of the lower bridge switch, thereby making the first storage The capacitance voltage of the capacitor increases linearly as the magnetizing inductor current increases.

In one embodiment of the invention, the input inductor current and the magnetizing inductor current charge the parasitic capacitance of the lower bridge switch when the lower bridge switch is non-conducting.

In one embodiment of the present invention, when the body diode of the upper bridge switch begins to conduct, the on current charges the clamp capacitor, wherein the on current is the input inductor current and the magnetizing inductor current.

In one of the embodiments of the present invention, when the upper bridge switch is turned on, the first switch current will slowly drop to zero to achieve zero voltage switching.

In one embodiment of the present invention, the capacitance voltage of the clamp capacitor is such that the output diode of the secondary side of the hybrid mode active clamp power converter is forward-conducting, but the output voltage of the secondary side is mapped back by the transformer. Primary side.

In one embodiment of the invention, the voltage value of the first voltage is 90 volts and the voltage value of the second voltage is 264 volts.

In summary, the hybrid mode active clamp power converter proposed in the embodiment of the present invention sets the boundary inductance value of the input inductor according to the boundary condition to operate the input inductor in the hybrid mode to make the hybrid mode active clamp. The power converter achieves zero voltage switching over the full load range, which in turn increases the power conversion efficiency of the hybrid mode active clamp power converter.

The detailed description of the present invention and the accompanying drawings are to be understood by the claims The scope is subject to any restrictions.

100‧‧‧ Mixed mode active clamp power converter

C _b ‧‧‧first storage capacitor

C _c ‧‧‧Clamp Capacitor

C _e ‧‧‧Parasitic capacitance

C _o ‧‧‧output capacitor

CS1‧‧‧First control signal

CS2‧‧‧second control signal

D _o ‧‧‧ output diode

i _in ‧‧‧Input inductor current

i _S1 ‧‧‧first switch current

a second switching current i _S2 ‧‧‧

i _Lr ‧‧‧Resonant inductor current

i _Lm ‧‧‧Magnetic inductor current

L11‧‧‧ primary side inductance

L12‧‧‧secondary inductance

L _in ‧‧‧Input inductance

L _lk ‧‧‧Resonant Inductance

L _m ‧‧‧Magnetic inductance

S1‧‧‧Bridge switch

S2‧‧‧Upper Bridge Switch

T0~t8‧‧‧Time

R _o ‧‧‧load

Output voltage V _o ‧‧‧

V _Cb , V _Cc ‧‧‧ capacitor voltage

V _DS1 ‧‧‧cross pressure

Input voltage source V _g ‧‧‧

i _p , i _Do , i _im , i _p ‧ ‧ current

HT‧‧‧Transformer

_{V g, V gs1, V gs2} , V Do ‧‧‧ voltage

1 is a detailed circuit diagram of a hybrid mode active clamp power converter according to an exemplary embodiment of the invention.

2 is a signal waveform diagram of a hybrid mode active clamp power converter according to an exemplary embodiment of the invention.

Various illustrative embodiments are described more fully hereinafter with reference to the accompanying drawings. However, the inventive concept may be embodied in many different forms and should not be construed as being limited to the illustrative embodiments set forth herein. Rather, these exemplary embodiments are provided so that this invention will be in the In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity. Similar numbers always indicate similar components.

It will be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, such elements are not limited by the terms. These terms are used to distinguish one element from another. Thus, a first element discussed below could be termed a second element without departing from the teachings of the inventive concept. As used herein, the term "and/or" includes any of the associated listed items and all combinations of one or more.

The hybrid mode active clamp power converter will be described below in conjunction with various embodiments, however, the following embodiments are not intended to limit the invention.

[Embodiment of Mixed Mode Active Clamp Power Converter]

The present disclosure provides a hybrid mode active clamp power converter with an input inductor operable in a continuous conduction mode (CCM) and a Boundary Conduction Mode, that is, a single-ended primary inductor converter (Single- Ended Primary Industry Converter (SPEIC), which enables the primary-side switch of the hybrid mode active clamp power converter to have the effect of zero voltage switching to improve the power efficiency of mobile devices (such as notebook computers) and to operate at high frequencies. To significantly reduce the volume, where zero voltage switching (ZVS) is defined as changing the state of the switch from an off state to an on state when the voltage across the switch is zero or near zero. Please refer to FIG. 1. FIG. 1 is a detailed circuit diagram of a hybrid mode active clamp power converter according to an exemplary embodiment of the invention. As shown in FIG. 1, the hybrid mode active clamp power converter 100 operates in a boundary conduction mode (BCM) or discontinuous conduction mode (DCM) by inputting an inductor current i _in to enable a hybrid mode active clamp power converter. Zero voltage switching is achieved over the full load range, which in turn increases the power conversion efficiency of the hybrid mode active clamp power converter.

The hybrid mode active clamp power converter 100 includes an input inductor L _in , a lower bridge switch S ₁ , an upper bridge switch S ₂ , a first storage capacitor C _b , a clamp capacitor C _c , a resonant inductor L _lk , a magnetizing inductance L _m The transformer HT, the output diode D _o and the output capacitor C _o , wherein the hybrid mode active clamp power converter 100 is connected to a load R _o and outputs an output voltage V _o . A first input terminal of inductor L is connected _in the positive input terminal of the voltage source V _g, wherein the operation input voltage source V _g between the first and second voltages. The control terminal of the switch S ₁ under the bridge receives a first control signal CS1, the first end of the bridge switch S ₁ is connected at the negative input terminal of the voltage source V _g. A control terminal S ₂ of the switch bridge receives the second control signal CS2, a first end of the bridge switch S ₂ is connected at a second end of the bridge switches S _1. A first end of the first energy storage capacitance C _b connected to the first end of the bridge switch S _1. The first end of the clamp capacitor C _c is connected to the second end of the upper bridge switch S _{2 , and} the second end of the clamp capacitor C _c is connected to the second end of the first storage capacitor C _b . The first end of the resonant inductor L _lk is connected to the second end of the lower bridge switch S ₁ . The first end of the magnetizing inductance L _m is connected to the resonant inductor L _lk , and the second end of the exciting inductor L _m is connected to the second end of the clamping capacitor C _c . The transformer HT has a primary side inductance L11 and a secondary side inductance L12, and the primary side inductance L11 is connected in parallel with the exciting inductance L _m , wherein the primary side inductance L11 and the secondary side inductance L12 have a mutual inductance effect.

The anode of the output diode D _o is connected to the first end of the secondary side inductor L12 (having a dot). D _o of the output capacitor C _o a first end connected to the output of the diode cathode and the second terminal of the output capacitor C _o is connected a second end of the secondary side inductor L12. It is worth noting that the input inductor L _in has a Boundary Inductance Value (BIV) and the boundary inductance value is set according to the first voltage and a heavy load (boundary condition) as a hybrid mode active clamp power supply. when the initial conditions of the converter 100, such that the lower bridge switch S ₁ is turned on, the input current i _in the inductor L _in the input inductor will charge the bridge and through the first switch S ₁ is the switching current i _S1 will equal the input inductor The sum of the current i _in and the magnetizing inductor current i _Lm in order to achieve zero voltage switching (ZVS). When the input voltage source V _g during the first operating voltage, the inductor L _in the input will operate in boundary conduction mode (BCM) and mixed such that the active-clamp mode power converter 100 to achieve zero-voltage switching. When the input voltage source V _g operates at a greater than the first voltage, the input inductor current i _in operates in a discontinuous conduction mode (DCM) and generates a negative current phenomenon, so that the body diode of the lower bridge switch S ₁ is easily turned on and The hybrid mode is actively clamped to the power converter for zero voltage switching.

Further, in the present embodiment, the voltage value of the first voltage is 90 volts, and the voltage value of the second voltage is 264 volts. The boundary inductance value of the input inductor L _in is set according to 90 volts and heavy load (that is, the load R _{o of the} full load) as an initial condition, so that the valley of the input inductor current i _in of the sine wave waveform is brought into contact with the zero current Bit, so the input inductor L _in will be operated in the boundary conduction mode (BCM) to enable the lower bridge switch S ₁ to perform zero voltage switching. Further, when the input voltage source V _g is operated between 90 volts to 264 volts, the input inductor current i _in sinusoidal waveforms will be shifted down the phenomenon of negative current, so that the input is operated _in the inductance L in discontinuous conduction mode (DCM), and such that the body-side switch S ₁ is turned on easily diode, wherein the input current i _in the inductor will charge the input inductor L _in. In addition, when the lower bridge switch S _{1 is} turned on, the first switching current i _S1 flowing through the lower bridge switch S ₁ is equal to the sum of the input inductor current i _in and the exciting inductor current i _Lm , so that the lower bridge switch S ₁ realizes zero voltage. Switch.

What follows is to further explain the working principle of the hybrid mode active clamp power converter 100.

Referring to FIG. 1 and FIG. 2 simultaneously, during the time t ₀ ~ t ₁ (the input voltage source V _g is zero), when the hybrid mode active clamp power converter 100 is above the bridge switch S _{2 is} not turned on and the input inductor current i _{When in} is zero, the magnetizing inductor current i _Lm charges the parasitic capacitance C _e (Parasitic capacitance) of the lower bridge switch S ₁ . During the time t ₁ ~ t ₂ (the input voltage source V _g is zero), when the hybrid mode actively clamps the power converter 100, the voltage across the first end and the second end of the bridge switch S ₁ is V _DS1 At zero voltage, the magnetizing inductor current i _Lm flows through the body diode of the lower bridge switch S ₁ , so that the capacitor voltage V _{Cb of the} first storage capacitor C _b linearly increases as the magnetizing inductor current i _Lm rises. During the time t ₂ ~ t ₃ (the input voltage source V _g is equal to the voltage V _gs1 ), the lower bridge switch S ₁ will start to conduct due to ZVS, so the input inductor current i _in will start to charge and flow through the lower bridge switch S The first switching current i _{S1 of 1} is equal to the sum of the input inductor current i _in and the exciting inductor current i _Lm . During the time t ₃ ~ t ₄ (the input voltage source voltage V _g is zero), the active clamp when the mixing mode power converter 100 under the bridge when the switch S1 is not conducting, the input current i _in the inductor current i _Lm will magnetizing inductance The parasitic capacitance C _{e of the} lower bridge switch S ₁ is charged.

During time t ₄ ~ t ₅ (the input voltage source V _{g is} equal to zero voltage), when the body diode of the bridge switch S ₂ starts to conduct on the hybrid mode active clamp power converter 100, the on current is applied to the clamp capacitor C. _c is charged, wherein the on current is the input inductor current i _in and the magnetizing inductor current i _Lm . During time t ₅ ~ t ₆ (the input voltage source V _{g is} equal to zero voltage), when the bridge switch S _{2 is} turned on above the hybrid mode active clamp power converter 100, the first switch current i _S1 will slowly fall to zero. In order to achieve zero voltage switching. During the period t ₆ ~ t ₇ (the input voltage source V _g is equal to the voltage V _gs2 ), the capacitance voltage V _{Cc of the} clamp capacitor C _c is sufficient for the mixed mode to actively clamp the output diode of the secondary side of the power converter 100 D _{o is} guided, but the output voltage Vo of the secondary side is mapped back to the primary side by n times the transformer (the ratio of the primary side inductance to the secondary side inductance is n:1), where n is a positive integer. During time t ₇ ~ t ₈ (the input voltage source V _{g is} equal to zero voltage), the resonant inductor current i _Lr will be smaller than the magnetizing inductor current i _Lm , so the secondary side output diode will switch with zero current (Zero Current Switch, ZCS) ) Way to close.

[Possible effects of the examples]

In summary, the hybrid mode active clamp power converter proposed in the embodiment of the present invention sets the boundary inductance value of the input inductor according to the boundary condition to operate the input inductor in the hybrid mode to make the hybrid mode active clamp. The power converter achieves zero voltage switching over the full load range, which in turn increases the power conversion efficiency of the hybrid mode active clamp power converter.

The invention can be embodied in any suitable form, including hardware, software, firmware, or any combination of the above. The invention may also be implemented in part by computer software executing on one or more data processors and/or digital signal processors. The units and components of the embodiments of the invention may be implemented in any suitable manner, physically, functionally, and logically. In fact, a function can be implemented in a single unit, in a plurality of units, or as part of other functional units. As far as the invention is concerned, it can be implemented on a single unit, or physically and functionally distributed between different units and processors.

The above description is only an embodiment of the present invention, and is not intended to limit the scope of the invention.

100‧‧‧ Mixed mode active clamp power converter

C _b ‧‧‧first storage capacitor

C _c ‧‧‧Clamp Capacitor

C _e ‧‧‧Parasitic capacitance

C _o ‧‧‧output capacitor

CS1‧‧‧First control signal

CS2‧‧‧second control signal

D _o ‧‧‧ output diode

i _in ‧‧‧Input inductor current

i _S1 ‧‧‧first switch current

i _S2 ‧‧‧Second switch current

i _Lr ‧‧‧Resonant inductor current

Input voltage source V _g ‧‧‧

HT‧‧‧Transformer

i _Lm ‧‧‧Magnetic inductor current

L11‧‧‧ primary side inductance

L12‧‧‧secondary inductance

L _in ‧‧‧Input inductance

L _lk ‧‧‧Resonant Inductance

L _m ‧‧‧Magnetic inductance

S1‧‧‧Bridge switch

S2‧‧‧Upper Bridge Switch

R _o ‧‧‧load

Output voltage V _o ‧‧‧

V _Cb , V _Cc ‧‧‧ capacitor voltage

V _DS1 ‧‧‧cross pressure

i _p, i _Do ‧‧‧ current

VDo‧‧‧ voltage

Claims (10)

A hybrid mode active clamp power converter includes: an input inductor having a first end coupled to a positive terminal of an input voltage source, wherein the input voltage source operates between a first voltage and a second voltage; a switch, the control end receives a first control signal, the first end of which is connected to the negative end of the input voltage source; and the upper bridge switch, the control end receives a second control signal, and the first end thereof is connected to the lower bridge switch a second end; a first storage capacitor having a first end connected to the first end of the lower bridge switch; a clamp capacitor having a first end connected to the second end of the upper bridge switch and a second end connected to the second end a second end of the first storage capacitor; a resonant inductor having a first end connected to the second end of the lower bridge switch; a magnetizing inductor having a first end connected to the resonant inductor and a second end connected to the clamp capacitor a second end; a transformer having a primary side inductance and a secondary side inductance, the primary side inductance being connected in parallel to the excitation inductance, wherein the primary side inductance and the secondary side inductance have a mutual inductance effect; and an output diode Body, the anode is connected to the secondary side a first end of the sense; and an output capacitor having a first end connected to the cathode of the output diode and a second end connected to the second end of the secondary side inductor, wherein the input inductor has a boundary inductance value and the The boundary inductance value is set according to the first voltage and a heavy load as an initial condition of the hybrid mode active clamp power converter, so that when the lower bridge switch is turned on, an input inductor current will be the input inductor Charging, and a first switch current flowing through one of the lower bridge switches is equal to a sum of the input inductor current and a magnetizing inductor current to achieve zero voltage switching, wherein when the input voltage source operates at the first voltage, The input inductor operates in the boundary conduction mode and causes the hybrid mode active clamp power converter to implement zero Voltage switching. The hybrid mode active clamp power converter of claim 1, wherein when the input voltage source operates at greater than the first voltage, the input inductor current operates in a discontinuous conduction mode and generates a negative current to The body diode of the lower bridge switch is made easy to conduct and the hybrid mode actively clamps the power converter to achieve zero voltage switching. The hybrid mode active clamp power converter of claim 1, wherein the mixed mode active clamp power converter achieves zero voltage by operating the input inductor current in the boundary conduction mode or the discontinuous conduction mode. Switch to improve power conversion efficiency. The hybrid mode active clamp power converter of claim 1, wherein the magnetizing inductor current charges a parasitic capacitance of the lower bridge switch when the upper bridge switch is non-conducting and the input inductor current is zero. The hybrid mode active clamp power converter of claim 1, wherein the magnetizing inductor current flows through the lower bridge switch when a voltage across the first end and the second end of the lower bridge switch is zero The body diode further increases the capacitance voltage of the first storage capacitor linearly as the magnetizing inductor current increases. The hybrid mode active clamp power converter of claim 1, wherein the input inductor current and the magnetizing inductor current charge a parasitic capacitance of the lower bridge switch when the lower bridge switch is not conducting. The hybrid mode active clamp power converter according to claim 1, wherein when the body diode of the upper bridge switch starts to conduct, a conduction current charges the clamp capacitor, wherein the conduction current is the input inductor current. With the magnetizing inductor current. The hybrid mode active clamp power converter of claim 1, when the upper bridge switch is turned on, the first switch current is slowly decreased to zero to achieve zero voltage switching. The hybrid mode active clamp power converter of claim 1, the capacitor voltage of the clamp capacitor is such that the hybrid mode actively clamps the output of the secondary side of the power converter The diode is in turn, but one of the output voltages on the secondary side is mapped back to the primary side by the transformer. The hybrid mode active clamp power converter of claim 1, wherein the first voltage has a voltage value of 90 volts and the second voltage has a voltage value of 264 volts.