CN206442300U - Three level Buck converters of ZVT - Google Patents

Abstract

The utility model is related to a kind of three level Buck converters of ZVT, electric capacity C₁、C₂、C₃With body diode D₁、D₂、D₃It is attempted by respective switching tube Q₁、Q₂、Q₃Drain electrode and source electrode on；Switching tube Q₁Drain electrode meet dc source V_inPositive pole, source electrode meet switching tube Q₂Drain electrode, switching tube Q₂Source electrode through primary side winding N_p2Meet switching tube Q₃Source electrode, switching tube Q₃Drain electrode all the way through primary side winding N_p1It is connected across switching tube Q₁With switching tube Q₂Contact on, another road meet switching tube Q₂With electric capacity C₄Contact on, switching tube Q₃Source electrode meet dc source V_dcNegative pole；The input side joint vice-side winding N of secondary rectifier bridge_s1, output side joint LC filter circuits, LC filter circuits include leakage inductance L₁, electric capacity C₅With resistance R.The utility model can realize switch tube zero voltage turn-on, reduce switching loss, improve circuit efficiency.

Description

Three level Buck converters of ZVT

Technical field

The utility model is related to a kind of three level Buck converters of ZVT, belongs to converters.

Background technology

Parallel network power generation is the Main way that people utilize photovoltaic power generation technology, has been obtained extensively in town and country now Application.At present, three traditional level Buck converters as shown in Figure 2, including switching tube Q₁And Q₂, electric capacity one end C₁Connect switch Pipe Q₁Source electrode and Q₂Between drain electrode, another terminate at sustained diode₁And D₂Between, the circuit structure has simple in construction Advantage.But when realizing higher step-down ratio, switching loss can be caused to increase simultaneously, not only circuit efficiency is low, and it is larger Dutycycle can cause the temperature rise of switching tube.Therefore, switching loss how is reduced, improving circuit efficiency turns into study hotspot.

The content of the invention

The purpose of this utility model, which is to provide one kind, can realize switch tube zero voltage turn-on, reduce switching loss, improve Three level Buck converters of the ZVT of the ZVT of circuit efficiency.

The utility model is that the technical scheme for reaching above-mentioned purpose is：A kind of three level Buck conversion of ZVT Device, it is characterised in that：Including primary side switch pipe Q₁、Q₂、Q₃, electric capacity C₁、C₂、C₃, the body diode D of switching tube₁、D₂、D₃, transformation The primary side winding N of device_p1、N_p2With vice-side winding N_s1And secondary rectifier bridge, wherein electric capacity C₁、C₂、C₃With body diode D₁、D₂、D₃And It is connected on each self-corresponding switching tube Q₁、Q₂、Q₃Drain electrode and source electrode on；The switching tube Q₁Drain electrode meet dc source V_dcPositive pole, Source electrode meets switching tube Q₂Drain electrode, switching tube Q₂Source electrode through primary side winding N_p2Meet switching tube Q₃Source electrode, switching tube Q₃Drain electrode All the way through primary side winding N_p1It is connected across switching tube Q₁With switching tube Q₂Contact on, another road meet switching tube Q₂With electric capacity C₄Connect On point, switching tube Q₃Source electrode meet dc source V_dcNegative pole；The input side joint vice-side winding N of the secondary rectifier bridge_s1, outlet side Connect LC filter circuits；Described LC filter circuits include leakage inductance L₁, electric capacity C₅With resistance R, electric capacity C₅One end after in parallel with resistance R Through leakage inductance L₁Connect one end, the other end of another termination secondary rectifier bridge outlet side of secondary rectifier bridge outlet side.

Three level Buck converters of the present utility model add switching tube Q3, by switching tube Q₂Source electrode through primary side winding N_p2Meet switching tube Q₃Source electrode, switching tube Q₃Drain electrode all the way through primary side winding N_p1It is connected across switching tube Q₁With switching tube Q₂Connect On point, another road meet switching tube Q₂With on electric capacity C4 contact, by switching tube Q₁Drain electrode and switching tube Q₃Source electrode connect direct current Source V_dcPositive and negative electrode on, by increasing the quantity of switching tube, while by primary side winding N_p1And primary side winding N_p2With electric capacity C₄With Switching tube Q₁、Q₂、Q₃Connection, and circuit structure is improved, pass through the parasitic capacitance and the leakage inductance of transformer being connected on each switching tube L₁ZVT is realized in energy storage, is efficiently reduced the loss of switching tube, is improved circuit efficiency, while also remaining tradition Three level Buck circuits reduce switch tube voltage stress and reduce the advantage of inductance.Each switching tube in the utility model circuit is equal Sofe Switch can be realized, can not only be held by reasonably controlling the turn-on sequence of each switching tube in converter with reducing switching tube By voltage, reduce the advantage of filter inductance, the level Buck converters of the utility model three are applied to vehicle power, photovoltaic generation etc. Application scenario.

Brief description of the drawings

Embodiment of the present utility model is described in further detail below in conjunction with the accompanying drawings.

Fig. 1 is three traditional level Buck circuit theory diagrams.

Fig. 2 is the circuit theory diagrams of three level Buck converters of the utility model ZVT.

Fig. 3 is the circuit theory diagrams of three level Buck converters operation modes 1 of the utility model ZVT.

Fig. 4 is the circuit theory diagrams of three level Buck converters operation modes 2 of the utility model ZVT.

Fig. 5 is the circuit theory diagrams of three level Buck converters operation modes 3 of the utility model ZVT.

Fig. 6 is the circuit theory diagrams of three level Buck converters operation modes 4 of the utility model ZVT.

Fig. 7 is the circuit theory diagrams of three level Buck converters operation modes 5 of the utility model ZVT.

Fig. 8 is the circuit theory diagrams of three level Buck converters operation modes 6 of the utility model ZVT.

Embodiment

As shown in Figure 2, three level Buck converters of ZVT of the present utility model, including primary side switch pipe Q₁、 Q₂、Q₃, electric capacity C₁、C₂、C₃, the body diode D of switching tube₁、D₂、D₃, the primary side winding N of transformer_p1、N_p2With vice-side winding N_s1And Secondary rectifier bridge, secondary rectifier bridge includes diode D₄~D₇.Electric capacity C₁、C₂、C₃With body diode D₁、D₂、D₃It is each right to be attempted by The switching tube Q answered₁、Q₂、Q₃Drain electrode and source electrode on, circuit realized by taking the energy of electric capacity away no-voltage turn on, effectively Switching loss is reduced, the purpose for improving circuit efficiency has been reached, as shown in Figure 2, each body diode positive pole of the utility model connects Source electrode, the negative pole of correspondence switching tube connect the drain electrode of switching tube, switching tube Q of the present utility model₁、Q₂、Q₃It is MOSFET pipes.

As shown in Figure 2, the utility model switching tube Q₁Drain electrode meet dc source V_dcPositive pole, source electrode meet switching tube Q₂Leakage Pole, switching tube Q2 source electrode connects switching tube Q3 source electrode, switching tube Q through primary side winding Np2₃Drain electrode all the way through primary side winding N_p1 It is connected across switching tube Q₁With switching tube Q₂Contact on, another road meet switching tube Q₂With on electric capacity C4 contact, and switching tube Q₃'s Source electrode meets dc source V_dcNegative pole.

As shown in Figure 2, the input side joint vice-side winding N of the utility model secondary rectifier bridge_s1, output side joint LC filtered electricals Road, secondary rectifier bridge of the present utility model uses diode D₄、D₅、D₆And D₇The full-bridge circuit of composition, and LC filter circuits include Leakage inductance L₁, electric capacity C₅With resistance R, electric capacity C₅Leakage inductance L of the one end through concatenating after in parallel with resistance R₁Connect secondary rectifier bridge outlet side One end, the other end of another termination secondary rectifier bridge outlet side, resistance R are used as load.

Can chronologically it be worked using three level Buck converters of ZVT of the present utility model, with following six kinds Operation mode, as shown in Fig. 3~8, wherein, primary side winding N_p1The number of turn and primary side winding N_p2The number of turn it is identical, i.e. N_p1=N_p2= W₁, vice-side winding N_s1The number of turn=W₂, the turn ratio n=W of transformer₂/W₁, transformer secondary is to the ratio between primary side, the utility model It is preferable component in circuit, the magnetizing inductance of transformer is sufficiently large, transformer leakage inductance and electric capacity C₄Harmonic period it is enough It is long.

And t₀、t₁、t₂、t₃、t₄And t₅For the initial time of six operation modes, t₆For the monocyclic final moment, and t is Converter operation time, three level Buck converter service times of the present utility model can be multiple cycles.

(1), in t₀≤t≤t₁Between operation mode 1：In t₀Before, sustained diode₃Conducting；t₀It is open-minded after moment Switching tube Q₁, on-off switching tube Q₂And Q₃, input power V_inIt is carried in winding N_p1On, V_C4Voltage-drop loading in winding N_p2On. In the presence of transformer leakage inductance, diode D in secondary rectifier bridge₄~D₇The all-pass change of current, transformer secondary short circuit V_inAnd V_c4Entirely Portion is added in transformer leakage inductance L₁On, in secondary rectifier bridge D₄、D₇And D₅、D₆The change of current terminates, I_d4=Io, I_d5=0, as shown in Figure 3, Switched at this in mode, switching tube Q₃No-voltage is open-minded, the electric current I of primary side_in, secondary voltage V_fuIt is expressed as：

V_fu=n (V_in+V_C4)；

I in formula_o1Output current during operation mode 1 is in for converter, D is the dutycycle of converter, V_c4For electric capacity C₄Both end voltage, V_inFor input voltage.

(2), in t₁＜ t≤t₂Between operation mode 2：In t₁After moment, leakage inductance L₁To parasitic capacitance C₁Charging, switch Pipe Q₁Voltage linear rises, switching tube Q₁Near zero voltage is turned off, as shown in Figure 4, in this operation mode, switching tube Q₁Zero electricity Pressure shut-off, switching tube Q₁Both sides voltage is expressed as：

V_C1=nI_o2Z₁Sinω₁(t-t₁)；

I in formula_o2Output current during mode 2, Z are in for converter₁Impedance is characterized, i.e.,ω₁It is electricity Circulate angle, i.e.,

(3), in t₂＜ t≤t₃Between operation mode 3：In t₂After moment, switching tube Q is turned on₃, on-off switching tube Q₁With Q₂, leakage inductance L₁Give electric capacity C2 electric discharges, switching tube Q₂Both end voltage linear decline, until electric charge is zero, as shown in Figure 5, is switched herein In mode, switching tube Q₂No-voltage is open-minded, electric capacity C₂The voltage at two ends is expressed as：

V_C2=V_in+V_C2-nI_o3Z₂Sinω₂(t-t₂)；

I in formula_o3Output current during mode 3, Z are in for converter₂Impedance is characterized, i.e.,ω₂It is electricity Circulate angle, i.e.,

(4), in t₃＜ t≤t₄Between operation mode 4：In t₃After moment, leakage inductance L₁Give electric capacity C₃Electric discharge, switching tube Q₃ Both end voltage linear rise, as shown in Figure 6, is switched in mode, switching tube Q at this₃Zero voltage turn-off, electric capacity C₃Both end voltage table It is shown as：

V_C3=nI_o4Z₃Sinω₃(t-t₃)；

I in formula_o4Output current during mode 4, Z are in for converter₃Impedance is characterized, i.e.,ω₃It is electricity Circulate angle, i.e.,

(5), in t₄＜ t≤t₅Between operation mode 5：In t₄After moment, leakage inductance L₁Give electric capacity C₁Electric discharge, electric capacity C₁'s Voltage linear declines, as shown in Figure 7, is switched at this in mode, switching tube Q₁No-voltage is open-minded, electric capacity C₁Both end voltage is expressed as：

V_C1=V_in-nI_o5Z₁Sinω(t-t₄)；

I in formula_o5Output current during mode 5 is in for converter.

(6), in t₅＜ t≤t₆Between operation mode 6：In t₅After moment, leakage inductance L₁To electric capacity C₂Charging, V_C2On linear Rise, as shown in Figure 8, switched at this in mode, switching tube Q2 zero voltage turn-offs, electric capacity C₂Both end voltage is expressed as：

V_C2=nI_o6Z₂Sinω₂(t-t₅)；

I in formula_o6Output current during mode 6 is in for converter.

The utility model above-mentioned electric capacity C1, C2 are identical with C3 capacitance, i.e. C₁=C₂=C₃=C, when the energy needed for Sofe Switch AmountWhen can realize Sofe Switch.

The utility model reduces switch tube voltage stress by reasonably controlling the turn-on sequence of each switching tube in converter With reduction inductance, while the switching tube in circuit can realize Sofe Switch, the loss of switching tube is efficiently reduced, electricity is improved The efficiency on road.

Claims (2)

1. a kind of three level Buck converters of ZVT, it is characterised in that：Including primary side switch pipe Q₁、Q₂、Q₃, electric capacity C₁、C₂、C₃, the body diode D of switching tube₁、D₂、D₃, the primary side winding N of transformer_p1、N_p2With vice-side winding N_s1And secondary rectification Bridge, wherein electric capacity C₁、C₂、C₃With body diode D₁、D₂、D₃It is attempted by each self-corresponding switching tube Q₁、Q₂、Q₃Drain electrode and source electrode On；The switching tube Q₁Drain electrode meet dc source V_dcPositive pole, source electrode meet switching tube Q₂Drain electrode, switching tube Q₂Source electrode through original Side winding N_p2Meet switching tube Q₃Source electrode, switching tube Q₃Drain electrode all the way through primary side winding N_p1It is connected across switching tube Q₁With switching tube Q₂Contact on, another road meet switching tube Q₂With electric capacity C₄Contact on, switching tube Q₃Source electrode meet dc source V_dcNegative pole；Institute State the input side joint vice-side winding N of secondary rectifier bridge_s1, output side joint LC filter circuits；Described LC filter circuits include leakage inductance L₁, electric capacity C₅With resistance R, electric capacity C₅One end is through leakage inductance L after in parallel with resistance R₁Connect one end, another of secondary rectifier bridge outlet side Terminate the other end of secondary rectifier bridge outlet side.

2. three level Buck converters of ZVT according to claim 1, it is characterised in that：The switching tube Q₁、 Q₂、Q₃It is MOSFET pipes.