CN110311552B - A current linear non-resonant soft-switching circuit based on diode branch - Google Patents

Abstract

The invention discloses a current linear resonance-free soft switching circuit based on a diode branch circuit, which comprises: the circuit comprises an inductor, an auxiliary inductor, a switching tube, a diode and a shunt branch, wherein one end of the inductor, a first electrode of the switching tube and one end of the auxiliary inductor are connected with one end of the shunt branch, the other end of the inductor is connected with a first external circuit, a second electrode of the switching tube is connected with a second external circuit, the other end of the shunt branch is connected with a third external circuit, the other end of the auxiliary inductor is connected with an anode of the diode, and a cathode of the diode is connected with a fourth external circuit; and when the inductor meets a first preset condition, the diode is conducted, and the capacitor connected in series with the auxiliary inductor meets a second preset condition, controlling the ZCS of the switching tube and the ZCS of the diode in the power electronic converter to be switched on. The soft switching circuit has a simple structure, and can be widely applied to various power electronic converters with high frequency, high power density and high efficiency.

Description

A current linear non-resonant soft-switching circuit based on diode branch

technical field

The invention relates to the technical field of power electronics, in particular to a current linear non-resonant soft switching circuit based on a diode branch.

Background technique

With the development of power electronic conversion technology, high frequency, high power density and high efficiency have become the future direction of power electronics and technology. However, the traditional power electronic converter works in a hard switching state, and the switching loss of the converter is relatively large, which affects the efficiency of the converter. At the same time, because the switching loss is proportional to the switching frequency, it also limits the development of high frequency and high power density of the converter. Soft switching technology reduces switching loss and makes the converter more efficient because it can realize ZVS (Zero Voltage Switch) turn-on of the switch tube, ZCS (Zero Current Switch, zero current switch) turn-off and ZCS turn-off of the diode. It has attracted much attention due to its high power, higher switching frequency, and higher power density.

Traditional soft-switching technologies include quasi-resonant circuits, zero-switching PWM (Pulse Width Modulation, pulse width modulation) circuits, and zero-switching PWM circuits. The quasi-resonant soft-switching circuit makes the voltage and current in the converter work in a resonant state, so that the converter has a higher current peak value and voltage peak value, which increases the device stress. At the same time, the circuit works in the frequency modulation state, and the converter is not easy to control. Both zero-switching PWM circuits and zero-switching PWM circuits can achieve soft switching, but due to the existence of resonance, the voltage stress and current stress will increase. In addition, these two circuits need to add more devices to realize soft switching, which increases the complexity and cost of the circuit.

Therefore, the soft-switching conversion circuit applied to the power electronic converter still needs further research and development.

SUMMARY OF THE INVENTION

The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

Therefore, the purpose of the present invention is to propose a current linear non-resonant soft-switching circuit based on a diode branch, the soft-switching circuit has a simple structure, and can realize the opening of the switch tube ZCS and the diode ZCS in the power electronic converter without resonance Turn off, reduce the switching loss of the switch tube, suppress the reverse recovery current of the diode, and can be widely used in various power electronic converters with high frequency, high power density and high efficiency.

In order to achieve the above object, an embodiment of the present invention provides a current linear non-resonant soft switching circuit based on a diode branch, including: an inductor L ₁ , an auxiliary inductor L _a1 , a switch S ₁ , a diode D ₁ and a shunt branch circuit, wherein _one end of the inductance L1, the _first electrode of the switch tube S1, and one end of the auxiliary inductance L _a1 are all connected to _one end of the shunt branch, and the other end of the inductance L1 It is connected to the _first external circuit, the second electrode of the switch tube S1 is connected to the second external circuit, the other end of the shunt branch is connected to the third external circuit, and the other end of the auxiliary inductance L _a1 is connected to the second external circuit. _The anode of the diode D1 is connected to the anode of the diode D1, and the cathode _of the diode D1 is connected to the fourth external circuit; when the inductor L1 satisfies the _first preset condition, the diode D1 is turned _on and is connected to the auxiliary inductor L _a1 When the capacitors connected in series meet the second preset condition, the ZCS of the switch tube and the ZCS of the diode in the power electronic converter are controlled to be turned on.

The current linear non-resonant soft switching circuit based on the diode branch according to the embodiment of the present invention has a simple structure, and can realize the turn-on of the switch tube ZCS and the turn-off of the diode ZCS in the power electronic converter under the condition of no resonance, thereby reducing the switching loss of the switch tube and suppressing the The reverse recovery current of the diode does not increase the voltage stress and current stress of the switch tube and diode, so it can be widely used in various high frequency, high power density, high efficiency power electronic converters, for future power electronic converters Soft switching technology provides a new solution.

In addition, the current linear non-resonant soft switching circuit based on the diode branch according to the above embodiments of the present invention may also have the following additional technical features:

Further, in an embodiment of the present invention, when the switch tube S ₁ is turned off, the shunt branch and the auxiliary inductor L _a1 share the current I _L1 flowing through the inductor L ₁ .

Further, in an embodiment of the present invention, the first to fourth external circuits are circuits other than the soft switching circuit in the power electronic converter.

Further, in an embodiment of the present invention, the switch S1 is _an N-type MOSFET or an IGBT.

Further, in an embodiment of the present invention, when the switch S1 is _an N-type MOSFET, the first electrode is a drain electrode, and the second electrode is a source electrode.

Further, in an embodiment of the present invention, when the switch S1 is _an IGBT, the first electrode is a collector, and the second electrode is an emitter.

Further, in an embodiment of the present invention, the power electronic converter is a switched capacitor type high-gain converter, a clamped capacitor type high-gain converter, a high-gain converter based on a voltage doubling unit, a quadratic high-gain converter. Gain converters or high gain converters based on voltage boosting units.

Additional aspects and advantages of the present invention will be set forth, in part, from the following description, and in part will be apparent from the following description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of embodiments taken in conjunction with the accompanying drawings, wherein:

1 is a structural diagram of a current linear non-resonant soft switching circuit based on a diode branch according to an embodiment of the present invention;

FIG. 2 is a topology diagram of a clamped capacitor type high-gain DC converter applying a current linear non-resonant soft switching circuit based on a diode branch according to an embodiment of the present invention;

3 is a simulation result of switching on the switch tube ZCS in a clamp capacitor type high-gain DC converter using a current linear non-resonant soft switching circuit based on a diode branch according to an embodiment of the present invention;

4 is a simulation result of diode ZCS turn-off in a capacitor-clamped high-gain DC converter using a current linear non-resonant soft-switching circuit based on a diode branch according to an embodiment of the present invention.

Detailed ways

The following describes in detail the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, and are intended to explain the present invention and should not be construed as limiting the present invention.

The following describes a current linear non-resonant soft switching circuit based on a diode branch according to an embodiment of the present invention with reference to the accompanying drawings.

FIG. 1 is a schematic structural diagram of a current linear non-resonant soft switching circuit based on a diode branch according to an embodiment of the present invention.

As shown in FIG. 1 , the current linear non-resonant soft switching circuit 10 based on a diode branch includes: an inductor L ₁ , an auxiliary inductor L _a1 , a switch S ₁ , a diode D ₁ and a shunt branch.

_One end of the inductance L1, the _first electrode of the switch tube S1, and _one end of the auxiliary inductance L _a1 are all connected to _one end of the shunt branch, and the other end of the inductance L1 is connected to the first external circuit. The second electrode is connected to the second external circuit, the other end of the shunt branch is connected to the third external circuit, the other end of the auxiliary inductor L _a1 is connected to the anode _of the diode D1, and the cathode _of the diode D1 is connected to the fourth external circuit; When the inductor L ₁ satisfies the first preset condition, the diode D ₁ is turned on, and the capacitor connected in series with the auxiliary inductor L _a1 satisfies the second preset condition, the ZCS of the switch tube and the ZCS of the diode in the power electronic converter are controlled to be turned on . The soft switching circuit 10 of the embodiment of the present invention has a simple structure, and can realize the turn-on of the switch tube ZCS and the turn-off of the diode ZCS in the power electronic converter without resonance, reduce the switching loss of the switch tube, and suppress the reverse recovery current of the diode, which can be widely used. It is used in various high frequency, high power density and high efficiency power electronic converters.

The first preset condition can be understood as the inductance L ₁ is large enough and can be regarded as a constant current source, and the second preset condition can be understood as when the first diode D ₁ is turned on, and the first auxiliary inductor L The capacitor connected in series with _a1 is large enough to be regarded as a constant voltage source. The soft switching circuit 10 of the embodiment of the present invention can realize the ZCS turn-on of the switch tube and the ZCS turn-off of the diode in the converter without resonance, thereby reducing the switching loss of the switch tube of the converter and suppressing the reverse direction of the diode recovery current, and can be widely used in power electronic converters.

Further, in an embodiment of the present invention, the switch tube S1 may be _an N-type MOSFET or an IGBT. When the switch tube S1 is _an N-type MOSFET, the first electrode is the drain electrode, and the second electrode is the source electrode; When S1 is _an IGBT, the first electrode is the collector and the second electrode is the emitter.

Further, in an embodiment of the present invention, the first to fourth external circuits are other circuits in the power electronic converter except the current linear non-resonant soft switching circuit based on the diode branch. The shunt branch and the auxiliary inductance L _a1 share the branch of the current I _L1 flowing through the inductance L ₁ during the off period of the switch tube S ₁ .

Among them, power electronic converters include but are not limited to: (1) switched capacitor type high-gain converters; (2) clamped capacitor type high-gain converters; (3) high-gain converters based on voltage doubling units; (4) A quadratic high-gain converter; (5) a high-gain converter based on a voltage boosting unit.

The function verification and circuit simulation verification of the soft switch circuit 10 according to the embodiment of the present invention are performed below with reference to a specific embodiment.

2 is a topology diagram of a clamp capacitor type high-gain DC converter applying the soft switching circuit 10 of the embodiment of the present invention according to an embodiment of the present invention, wherein the part in bold is the soft switching circuit 10 of the embodiment of the present invention, The non-bold part is the external circuit in the embodiment of the present invention, the branch where the capacitor C ₁ is located is the shunt branch in the embodiment of the present invention, and the capacitor C ₂ is the first embodiment of the present invention when the diode D ₁ is turned on. The auxiliary inductance L _a1 is a capacitor connected in series, and the inductance L _s is the line parasitic inductance.

In order to verify the soft switching circuit 10 of the embodiment of the present invention, a simulation platform is built according to the simulation parameters in Table 1, and FIG. 3 and FIG. 4 are the simulation results. From the simulation results of FIG. 3 and FIG. 4 , it can be found that by applying the soft switch circuit 10 of the embodiment of the present invention, the switch tube S ₁ of the clamp capacitor type high gain realizes the ZCS turn-on, and the diodes D ₁ and D ₂ realize the ZCS It is turned off, and no resonance occurs in the circuit, and there is no current stress on the switch and diode. Among them, Table 1 is the simulation parameter table.

Table 1

parameter name parameter value Input source V_in 40V Switching frequency f_s 200kHz Duty cycle D 0.643 Inductance L₁ 300μH Auxiliary inductance L_a1 2μH Line parasitic inductance L_s 70nH Capacitor C₁ 30μF Capacitor C₂ 30μF Capacitor C₃ 200μF Output load R_L 500Ω

To sum up, the simulation constructed according to Table 1 and FIG. 2 verifies that the soft-switching circuit 10 of the embodiment of the present invention can be applied to a power electronic converter, realizes the ZCS turn-on of the switch tube and the ZCS turn-off of the diode, and reduces the switching loss of the converter , suppresses the reverse current of the diode.

The current linear non-resonant soft switching circuit based on the diode branch proposed by the embodiment of the present invention has a simple structure, and can realize the switching on of the switch ZCS and the off of the diode ZCS in the power electronic converter under the condition of no resonance, thereby reducing the switching loss of the switch. , suppress the reverse recovery current of the diode, and at the same time do not increase the voltage stress and current stress of the switch tube and diode, so that it can be widely used in various high frequency, high power density, high efficiency power electronic converters, for the future power electronics Converter soft switching technology provides a new solution.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise expressly and specifically defined.

In the present invention, unless otherwise expressly specified and limited, a first feature "on" or "under" a second feature may be in direct contact between the first and second features, or the first and second features indirectly through an intermediary touch. Also, the first feature being "above", "over" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is level higher than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature has a lower level than the second feature.

In the description of this specification, description with reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., mean specific features described in connection with the embodiment or example , structure, material or feature is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine the different embodiments or examples described in this specification, as well as the features of the different embodiments or examples, without conflicting each other.

Although the embodiments of the present invention have been shown and described above, it should be understood that the above-mentioned embodiments are exemplary and should not be construed as limiting the present invention. Embodiments are subject to variations, modifications, substitutions and variations.

Claims (7)

1. A current linear non-resonant soft switching circuit based on a diode branch, characterized in that it comprises: an inductance L ₁ , an auxiliary inductance L _a1 , a switch tube S ₁ , a diode D ₁ and a shunt branch, wherein, _One end of the inductance L1, the _first electrode of the switch tube S1, and one end of the auxiliary inductance L _a1 are all connected to _one end of the shunt branch, and the other end of the inductance L1 is connected to the first external connected to the circuit, the second electrode _of the switch tube S1 is connected to the second external circuit, the other end of the shunt branch is connected to the third external circuit, the other end _of the auxiliary inductor L _a1 is connected to the diode D1 _The anode of the diode D1 is connected to the fourth external circuit; When the inductor L ₁ satisfies the first preset condition, the diode D ₁ is turned on, and the capacitor connected in series with the auxiliary inductor L _a1 satisfies the second preset condition, the ZCS of the switch tube in the power electronic converter is controlled to be turned on and the ZCS of the diode is turned off, wherein the _first preset condition is that the inductance L1 is large enough, and when the inductance L1 satisfies the _first preset condition, the inductance L1 is regarded as _a constant current source; the The second preset condition is that the diode D1 is turned _on and the capacitance in series with the auxiliary inductor L _a1 is large enough, and the capacitor connected in series with the auxiliary inductor L _a1 when the diode D1 is turned _on satisfies the second preset condition When conditions are set, the diode D1 is regarded as _a constant voltage source. 2 . The soft switching circuit according to claim 1 , wherein during the period when the switch tube S ₁ is turned off, the shunt branch and the auxiliary inductance L _a1 share the responsibility of the power flowing through the inductance L ₁ . 3 . current I _L1 . 3 . The soft-switching circuit of claim 1 , wherein the first to fourth external circuits are circuits other than the soft-switching circuit in the power electronic converter. 4 . 4 . The soft switching circuit according to claim 1 , wherein the switch tube S ₁ is an N-type MOSFET or an IGBT. 5 . 5 . The soft switching circuit according to claim 4 , wherein when the switch S1 is _an N-type MOSFET, the first electrode is a drain electrode, and the second electrode is a source electrode. 6 . 6 . The soft switching circuit according to claim 4 , wherein when the switch S1 is _an IGBT, the first electrode is a collector, and the second electrode is an emitter. 7 . 7. The soft-switching circuit according to any one of claims 1-6, wherein the power electronic converter is a switched capacitor type high gain converter, a clamp capacitor type high gain converter, a voltage doubling unit based high-gain converters, quadratic high-gain converters or high-gain converters based on voltage boosting units.

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