CN101588126B - Wide load characteristic ZVZCS three-level DC-DC converter - Google Patents

Abstract

A wide load characteristic ZVZCS three-level DC-DC converter relates to a three-level converter. The aim of the invention is to settle the problems of large switching loss, generation of large voltagepeak, easily switching tube damage and series electromagnetic interference problem existing in the prior three-level converter. The anode of a voltage source is simultaneously connected with one end of a first capacitor, one end of a fifth capacitor, a drain end of a first insulated-gate type field effect transistor, the cathode of a first diode, the cathode of a fifth diode and the collector electrode end of a fifth triode. The cathode of the voltage source is simultaneously connected with one end of a fourth capacitor, one end of the sixth capacitor, a source end of a fourth insulated-gate type field effect transistor, an anode of a fourth diode, an anode of a sixth diode and the emitter end of a sixth triode (S6). The wide load characteristic ZVZCS three-level DC-DC converter of the invention is also added with an auxiliary rectifying circuit and an active clamp circuit. The wide load characteristic ZVZCS three-level DC-DC converter of the invention has the advantages of high resetting speed of the primary side current, no overshoot voltage of the secondary side, etc. Furthermore the wide load characteristic ZVZCS three-level DC-DC converter of the invention settles the problems of duty ratio loss, primary side circumfluence, parasitic oscillation, etc. The efficiency of the converter is increased. The switching loss and the electromagnetic interference are reduced.

Description

The ZVZCS three-level DC-DC converter of wide load characteristic

Technical field

The present invention relates to three-level DC-DC converter, be specifically related to the ZVZCS three-level converter.

Background technology

In some occasions, Arc Welding Power etc. for example can often operate in open-circuit condition and can not shut down.In this case, the ZVS of common three-level converter (zero voltage switch) condition disappears, and switching tube is operated under the hard switching state, and switching loss is big, and efficient is low, and can produce big due to voltage spikes, easily causes the damage of switching tube; Electromagnetic interference (Electro Magnetic Interference is called for short EMI) problem is serious simultaneously, the normal operation of electronic equipment around the influence.

Summary of the invention

The present invention produces excessive due to voltage spikes for the switching loss that solves existing three-level converter existence is big, easily causes the damage of switching tube, the serious problem of while electromagnetic interference, and the ZVZCS three-level DC-DC converter of a kind of wide load characteristic that proposes.

The ZVZCS three-level DC-DC converter of wide load characteristic, it comprises first diode to the, eight diodes, first electric capacity to the, six electric capacity, first insulating gate type field effect tube to the, four insulating gate type field effect tubes, the 5th triode, the 6th triode, striding capacitance, resonant inductance, first inductance, filter capacitor, load resistance, first rectifier diode, second rectifier diode and main transformer; One end of the 5th electric capacity links to each other with the drain electrode end of positive voltage terminal, first insulating gate type field effect tube, the negative electrode of first diode, an end of first electric capacity, the collector terminal of the 5th triode and the negative electrode of the 5th diode simultaneously; The other end of the 5th electric capacity links to each other with the anode of the 7th diode, the negative electrode of the 8th diode and an end of the 6th electric capacity simultaneously, and the other end of the 6th electric capacity links to each other with the source terminal of negative voltage side, the 4th insulating gate type field effect tube, the anode of the 4th diode, an end of the 4th electric capacity, the emitter terminal of the 6th triode and the anode of the 6th diode simultaneously; The negative electrode of the 7th diode links to each other with an end of striding capacitance, the source terminal of first insulating gate type field effect tube, the drain electrode end of second insulating gate type field effect tube, the anode of first diode, the negative electrode of second diode, the other end of first electric capacity and an end of second electric capacity simultaneously; The anode of the 8th diode links to each other with the other end of striding capacitance, the source terminal of the 3rd insulating gate type field effect tube, the drain electrode end of the 4th insulating gate type field effect tube, the anode of the 3rd diode, the negative electrode of the 4th diode, an end of the 3rd electric capacity and the other end of the 4th electric capacity simultaneously; The source terminal of second insulating gate type field effect tube links to each other with the drain electrode end of the 3rd insulating gate type field effect tube, the anode of second diode, the negative electrode of the 3rd diode, the other end of second electric capacity, the other end of the 3rd electric capacity and the end of the same name of the former limit of main transformer winding simultaneously; The non-same polarity of the former limit of main transformer winding links to each other with an end of resonant inductance; The other end of resonant inductance links to each other with the emitter terminal of the 5th triode, the collector terminal of the 6th triode, the anode of the 5th diode and the negative electrode of the 6th diode simultaneously; The non-same polarity of main transformer secondary winding links to each other with the anode of first rectifier diode, the end of the same name of main transformer secondary winding links to each other with the anode of second rectifier diode, the negative electrode of first rectifier diode links to each other with an end of first inductance and the negative electrode of second rectifier diode simultaneously, and the other end of first inductance links to each other with an end of filter capacitor and an end of load resistance simultaneously; The other end of filter capacitor links to each other with the other end of load resistance and the centre tap of main transformer secondary winding simultaneously; It also comprises auxiliary transformer, the 3rd rectifier diode, the 4th rectifier diode, second inductance, the 7th insulating gate type field effect tube and clamp capacitor; The source terminal of the 7th insulating gate type field effect tube links to each other with the negative electrode of first rectifier diode, the negative electrode of second rectifier diode and an end of first inductance simultaneously; The drain electrode end of the 7th insulating gate type field effect tube links to each other with an end of clamp capacitor and an end of second inductance simultaneously, and the other end of second inductance links to each other with the negative electrode of the 3rd rectifier diode and the negative electrode of the 4th rectifier diode simultaneously; The anode of the 3rd rectifier diode links to each other with the non-same polarity of auxiliary transformer secondary winding, and the anode of the 4th rectifier diode links to each other with the end of the same name of auxiliary transformer secondary winding; The other end of clamp capacitor links to each other with the other end of filter capacitor simultaneously, the centre tap of auxiliary transformer secondary winding, the centre tap of main transformer secondary winding and the other end of load resistance link to each other; The end of the same name of the former limit of auxiliary transformer winding links to each other with the other end of the 5th electric capacity, an end of the 6th electric capacity, the anode of the 7th diode and the negative electrode of the 8th diode simultaneously; The non-same polarity of the former limit of auxiliary transformer winding links to each other with the source terminal of second insulating gate type field effect tube, the drain electrode end of the 3rd insulating gate type field effect tube, the anode of second diode, the negative electrode of the 3rd diode, the other end of second electric capacity, the other end of the 3rd electric capacity and the end of the same name of the former limit of main transformer winding simultaneously.

The present invention has low, the no excessive low advantage of due to voltage spikes, electromagnetic interference of switching loss.Increased auxiliary transformer between dividing potential drop electric capacity mid point and the three level brachium pontis mid points, finished the discharging and recharging of three level brachium pontis switching tube junction capacitance, realized the zero voltage switch when unloaded by the former limit of auxiliary transformer exciting current; Simultaneously auxiliary transformer provides energy for clamp capacitor, and clamp voltage is maintained higher level, makes electric current return zero rapidly after reflexing to former limit, thereby realizes the Zero Current Switch of two level brachium pontis switching tubes.Compare with traditional Zero Current Switch converter, novel topology has solved problems such as duty-cycle loss, former side ring stream, parasitic oscillation when primary current returns the advantage that zero velocity is fast, there is not voltage overshoot in secondary having, improve the efficient of converter, expanded its range of application.

Description of drawings

Fig. 1 is circuit theory diagrams of the present invention; Fig. 2 is a groundwork oscillogram of the present invention; Fig. 3 is the circuit theory diagrams of switch mode 1; Fig. 4 is the circuit theory diagrams of switch mode 2; Fig. 5 is the circuit theory diagrams of switch mode 3; Fig. 6 is the circuit theory diagrams of switch mode 4; Fig. 7 is the circuit theory diagrams of switch mode 5; Fig. 8 is the circuit theory diagrams of switch mode 6; Fig. 9 is the circuit theory diagrams of switch mode 7; Figure 10 is the circuit theory diagrams of switch mode 8; Figure 11 is the circuit theory diagrams of switch mode 9; Figure 12 is the circuit theory diagrams of switch mode 10; Figure 13 is the circuit theory diagrams of switch mode 11; Figure 14 is driving and the drain-source voltage oscillogram of the first insulating gate type field effect tube S1 when nominal load, wavy curve 1 is at the 10V/ lattice, the drive waveforms of the first insulating gate type field effect tube S1 under the 5 μ s/ lattice, wavy curve 2 is the 100V/ lattice, the drain-source voltage waveform of the first insulating gate type field effect tube S1 under the 5 μ s/ lattice; Figure 15 is driving and the drain-source voltage oscillogram of the second insulating gate type field effect tube S2 when nominal load, wavy curve 1 is at the 10V/ lattice, the drive waveforms of the second insulating gate type field effect tube S2 under the 5 μ s/ lattice, wavy curve 2 is the 100V/ lattice, the drain-source voltage waveform of the second insulating gate type field effect tube S2 under the 5 μ s/ lattice; Figure 16 is driving and the main transformer Tr1 primary current oscillogram of the 5th triode S5 when nominal load, wavy curve 1 is the 10V/ lattice, the drive waveforms of the 5th triode S5 under the 5 μ s/ lattice, wavy curve 2 is the 2V/ lattice, main transformer Tr1 primary current waveform under the 5 μ s/ lattice; Figure 17 is the voltage oscillogram of two brachium pontis mid point Vab, and wavy curve 1 is the 100V/ lattice, the voltage waveform of two brachium pontis mid point Vab under the 5 μ s/ lattice; Figure 18 is the voltage oscillogram of three level brachium pontis and two level brachium pontis mid-point voltage Vab, and wavy curve 1 is the 100V/ lattice, the voltage waveform of three level brachium pontis and two level brachium pontis mid-point voltage Vab under the 10 μ s/ lattice; Figure 19 is driving and the drain-source voltage oscillogram of the first insulating gate type field effect tube S1 when zero load, wavy curve 1 is the 10V/ lattice, the drive waveforms of the first insulating gate type field effect tube S1 under the 5 μ s/ lattice, wavy curve 2 is the 100V/ lattice, the drain-source voltage waveform of the first insulating gate type field effect tube S1 under the 5 μ s/ lattice; Figure 20 is driving and the drain-source voltage oscillogram of the second insulating gate type field effect tube S2 when zero load, wavy curve 1 is at the 10V/ lattice, the drive waveforms of the second insulating gate type field effect tube S2 under the 5 μ s/ lattice, wavy curve 2 is the 100V/ lattice, the drain-source voltage waveform of the second insulating gate type field effect tube S2 under the 5 μ s/ lattice; Figure 21 is an efficiency curve diagram of the present invention.

Embodiment

Embodiment one: in conjunction with Fig. 1 present embodiment is described, present embodiment comprises the first diode D1 to the, eight diode D8, first capacitor C, 1 to the 6th capacitor C 6, the first insulating gate type field effect tube S1 to the, four insulating gate type field effect tube S4, the 5th triode S5, the 6th triode S6, striding capacitance Css, resonant inductance Lr, the first inductance L f1, filter capacitor C0, load resistance R0, the first rectifier diode DR1, the second rectifier diode DR2 and main transformer Tr1; One end of the 5th capacitor C 5 links to each other with the drain electrode end of positive voltage terminal, the first insulating gate type field effect tube S1, the negative electrode of the first diode D1, an end of first capacitor C 1, the collector terminal of the 5th triode S5 and the negative electrode of the 5th diode D5 simultaneously; The other end of the 5th capacitor C 5 links to each other with the anode of the 7th diode D7, the negative electrode of the 8th diode D8 and an end of the 6th capacitor C 6 simultaneously, and the other end of the 6th capacitor C 6 links to each other with the source terminal of negative voltage side, the 4th insulating gate type field effect tube S4, the anode of the 4th diode D4, an end of the 4th capacitor C 4, the emitter terminal of the 6th triode S6 and the anode of the 6th diode D6 simultaneously; The negative electrode of the 7th diode D7 links to each other with the end of striding capacitance Css, the source terminal of the first insulating gate type field effect tube S1, the drain electrode end of the second insulating gate type field effect tube S2, the anode of the first diode D1, the negative electrode of the second diode D2, the other end of first capacitor C 1 and an end of second capacitor C 2 simultaneously; The anode of the 8th diode D8 links to each other with the other end of striding capacitance Css, the source terminal of the 3rd insulating gate type field effect tube S3, the drain electrode end of the 4th insulating gate type field effect tube S4, the anode of the 3rd diode D3, the negative electrode of the 4th diode D4, an end of the 3rd capacitor C 3 and the other end of the 4th capacitor C 4 simultaneously; The source terminal of the second insulating gate type field effect tube S2 links to each other with the drain electrode end of the 3rd insulating gate type field effect tube S3, the anode of the second diode D2, the negative electrode of the 3rd diode D3, the other end of second capacitor C 2, the other end of the 3rd capacitor C 3 and the end of the same name of the former limit of main transformer Tr1 winding simultaneously; The non-same polarity of the former limit of main transformer Tr1 winding links to each other with the end of resonant inductance Lr; The other end of resonant inductance Lr links to each other with the emitter terminal of the 5th triode S5, the collector terminal of the 6th triode S6, the anode of the 5th diode D5 and the negative electrode of the 6th diode D6 simultaneously; The non-same polarity of main transformer Tr1 secondary winding links to each other with the anode of the first rectifier diode DR1, the end of the same name of main transformer Tr1 secondary winding links to each other with the anode of the second rectifier diode DR2, the negative electrode of the first rectifier diode DR1 links to each other with the end of the first inductance L f1 and the negative electrode of the second rectifier diode DR2 simultaneously, and the other end of the first inductance L f1 links to each other with the end of filter capacitor C0 and the end of load resistance R0 simultaneously; The other end of filter capacitor C0 links to each other with the other end of load resistance R0 and the centre tap of main transformer Tr1 secondary winding simultaneously; It also comprises auxiliary transformer Tr2, the 3rd rectifier diode DR3, the 4th rectifier diode DR4, the second inductance L f2, the 7th insulating gate type field effect tube S7 and clamp capacitor Cc; The source terminal of the 7th insulating gate type field effect tube S7 links to each other with the negative electrode of the first rectifier diode DR1, the negative electrode of the second rectifier diode DR2 and the end of the first inductance L f1 simultaneously; The drain electrode end of the 7th insulating gate type field effect tube S7 links to each other with the end of clamp capacitor Cc and the end of the second inductance L f2 simultaneously, and the other end of the second inductance L f2 links to each other with the negative electrode of the 3rd rectifier diode DR3 and the negative electrode of the 4th rectifier diode DR4 simultaneously; The anode of the 3rd rectifier diode DR3 links to each other with the non-same polarity of auxiliary transformer Tr2 secondary winding, and the anode of the 4th rectifier diode DR4 links to each other with the end of the same name of auxiliary transformer Tr2 secondary winding; The other end of clamp capacitor Cc links to each other with the other end of filter capacitor C0 simultaneously, the centre tap of auxiliary transformer Tr2 secondary winding, the centre tap of main transformer Tr1 secondary winding and the other end of load resistance R0 link to each other; The end of the same name of the former limit of auxiliary transformer Tr2 winding links to each other with the other end of the 5th capacitor C 5, an end of the 6th capacitor C 6, the anode of the 7th diode D7 and the negative electrode of the 8th diode D8 simultaneously; The non-same polarity of the former limit of auxiliary transformer Tr2 winding links to each other with the source terminal of the second insulating gate type field effect tube S2, the drain electrode end of the 3rd insulating gate type field effect tube S3, the anode of the second diode D2, the negative electrode of the 3rd diode D3, the other end of second capacitor C 2, the other end of the 3rd capacitor C 3 and the end of the same name of the former limit of main transformer Tr1 winding simultaneously.Operation principle of the present invention:

Before analyzing its operation mode, make following hypothesis: (1) all switching tubes, diode, inductance, electric capacity are desirable components and parts; (2) C5 and C6 divide equally input voltage, can equivalence be two V _In/ 2 voltage source; (3) striding capacitance Css control is proper, and voltage keeps V on it _In/ 2 is constant; (4) junction capacitance of each switching tube is Cp, and transformer voltage ratio is K.

In one-period, being divided into is 22 mode, the main circuit waveform of first work period as shown in Figure 2, its operational modal analysis is as follows:

(1) switch mode 1[t ₀, t ₁].Referring to Fig. 3, t ₀In the past, the 3rd insulating gate type field effect tube S3, the 5th triode S5 conducting, the former limit of main transformer Tr1 provides energy to its secondary, and the voltage on the former and deputy limit of main transformer Tr1 is respectively V _In/ 2, V _In/ (2k ₁), primary current i _pBe I _o/ k ₁, k wherein ₁Be the main transformer no-load voltage ratio.

t ₀Constantly turn-off the 3rd insulating gate type field effect tube S3, output current I _oReflex to the former limit of main transformer Tr1 and the former limit exciting current of auxiliary transformer Tr2 and give second capacitor C 2 discharges jointly, give the 3rd capacitor C 3 chargings, v _C2Linear decline, v _C3Beginning is linear rises v _AbThe linear rising.

$v_{C3}\left(t\right)=\frac{\frac{I_o}{{\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="H2009100723654E00011.png,H2009100723654E00042.png"\; state="\{\{state\}\}">k</figure-callout>}}_1}+I_{\mathrm{<figure-callout\; id="2"\; label="m\; max\; C"\; filenames="H2009100723654E00032.png,H2009100723654E00041.png"\; state="\{\{state\}\}">m</figure-callout>}\max }}{C_{}}(t-t_0)$ Formula 1

$v_{C2}\left(t\right)=\frac{V_{\mathrm{in}}}{2}-\frac{\frac{I_o}{{\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="H2009100723654E00011.png,H2009100723654E00042.png"\; state="\{\{state\}\}">k</figure-callout>}}_1}+I_{\mathrm{<figure-callout\; id="2"\; label="m\; max\; C"\; filenames="H2009100723654E00032.png,H2009100723654E00041.png"\; state="\{\{state\}\}">m</figure-callout>}\max }}{C_{}}(t-t_0)$ Formula 2

$v_{\mathrm{ab}}\left(t\right)=\frac{\frac{I_o}{{\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="H2009100723654E00011.png,H2009100723654E00042.png"\; state="\{\{state\}\}">k</figure-callout>}}_1}+I_{\mathrm{<figure-callout\; id="2"\; label="m\; max\; C"\; filenames="H2009100723654E00032.png,H2009100723654E00041.png"\; state="\{\{state\}\}">m</figure-callout>}\max }}{C_{}}(t-t_0)-\frac{V_{\mathrm{in}}}{2}$ Formula 3

At t ₁Constantly, v _C2Drop to zero, v _C3Rise to V _InThe/2, the 3rd insulating gate type field effect tube S3 is that no-voltage is turn-offed v _AbBe zero.In this mode, i _pMaintain I _o/ k ₁The duration of this mode is

${\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="H2009100723654E00011.png,H2009100723654E00042.png"\; state="\{\{state\}\}">t</figure-callout>}}_{\mathrm{0,1}}=\frac{V_{\mathrm{in}}({\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="H2009100723654E00032.png,H2009100723654E00041.png"\; state="\{\{state\}\}">C</figure-callout>}}_2+C_3)}{2(\frac{I_o}{{\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="H2009100723654E00011.png,H2009100723654E00042.png"\; state="\{\{state\}\}">k</figure-callout>}}_1}+I_{m\max })}$ Formula 4

(2) switch mode 2[t ₁, t ₂].Referring to Fig. 4, t ₁The first diode D1 of the first insulating gate type field effect tube S1, the second insulating gate type field effect tube S2 parallel connection and second diode D2 nature conducting constantly, the current potential of the first insulating gate type field effect tube S1, the second insulating gate type field effect tube S2 is clamped zero, and it is then open-minded for no-voltage to open the first insulating gate type field effect tube S1, the second insulating gate type field effect tube S2 this moment.At this mode, v _Ab=0, i _pMaintain I _o/ k ₁

(3) switch mode 3[t ₂, t ₃].Referring to Fig. 5, t ₂Constantly open the first insulating gate type field effect tube S ₁, the second insulating gate type field effect tube S2 and the 7th insulating gate type field effect tube S7, clamp capacitor Cc begins discharge, clamp voltage V _CcReflex to its former limit by main transformer Tr1, affact on the resonant inductance Lr, make primary current i _pReturn zero rapidly, a part of load current I _oThe clamp capacitor Cc that flows through, its discharging current i _CcLinear increasing.

$i_p\left(t\right)=\frac{k_1{V}_{\mathrm{CC}}}{L_r}(t-t_2)-\frac{I_o}{{\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="H2009100723654E00011.png,H2009100723654E00042.png"\; state="\{\{state\}\}">k</figure-callout>}}_1}$ Formula 5

$i_{\mathrm{Cc}}\left(t\right)=\frac{k^2{V}_{\mathrm{CC}}}{L_r}(t-t_2)$ Formula 6

At t ₃Constantly, i _pRise to zero, i _CcRise to I _o, the duration of this mode is

${\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="H2009100723654E00032.png,H2009100723654E00041.png"\; state="\{\{state\}\}">\; <figure-callout\; id="3"\; label="t"\; filenames="H2009100723654E00032.png,H2009100723654E00042.png"\; state="\{\{state\}\}">t</figure-callout>\; </figure-callout>}}_{\mathrm{2,3}}=\frac{I_o{\mathrm{<figure-callout\; id="1"\; label="L\; r\; k"\; filenames="H2009100723654E00011.png,H2009100723654E00042.png"\; state="\{\{state\}\}">L</figure-callout>}}_r}{{k_{}}^{}}$ Formula 7

(4) switch mode 4[t ₃, t ₄].Referring to Fig. 6, in this mode, main transformer Tr1 primary current i _pBe zero, clamp capacitor Cc is in conducting state, the electric current I of load resistance R0 _oThrough clamp capacitor Cc afterflow, the first rectifier diode Dr1, the second rectifier diode Dr2 all are in cut-off state.

(5) switch mode 5[t ₄, t ₅].Referring to Fig. 7, t ₄Constantly turn-off the 7th insulating gate type field effect tube S7, commutating voltage V _rReduce to zero rapidly, the first rectifier diode Dr1, the second rectifier diode Dr2 remove partially anti-, the electric current I of load resistance R0 _oThrough the first rectifier diode Dr1, the second rectifier diode Dr2 afterflow, v _AbAnd i _pAll maintain zero.Auxiliary transformer Tr2 begins to charge to clamp capacitor Cc.The duration of this mode is determined by the phase shift value.

(6) switch mode 6[t ₅, t ₆].Referring to Fig. 8, t ₅Constantly turn-off the 5th triode S5, because i _pBe zero, all few sons of the 5th triode S5 are all compound to be fallen, and therefore the 5th triode S5 is a zero-current switching, has solved the current tail phenomenon when IGBT turn-offs.V in this mode _Ab=0, auxiliary transformer Tr2 continues to charge to clamp capacitor Cc.The duration of this mode is by the Dead Time decision that lags behind between pipe the 5th triode S5, the 6th triode S6.

(7) switch mode 7[t ₆, t ₇].Referring to Fig. 9, at t ₆Constantly open the 6th triode S6, this moment, the first rectifier diode Dr1 and the second rectifier diode Dr2 were in conducting afterflow state, and the former and deputy limit winding voltage of main transformer Tr1 is zero, and voltage source vin is added on the resonant inductance Lr, primary current i _pRise by zero beginning is linear.

$i_p\left(t\right)=\frac{V_{\mathrm{in}}}{L_r}(t-t_6)$ Formula 8

t ₇Moment i _pRise to I _o/ k ₁(k ₁Be transformer T ₁No-load voltage ratio), the second rectifier diode Dr2 turn-offs, the first rectifier diode Dr1 conducting.In this mode, v _Ab=V _In, auxiliary transformer Tr2 gives clamp capacitor Cc charging.The duration of this mode is

${\mathrm{<figure-callout\; id="6"\; label="t"\; filenames="H2009100723654E00031.png,H2009100723654E00041.png"\; state="\{\{state\}\}">\; <figure-callout\; id="7"\; label="t"\; filenames="H2009100723654E00011.png,H2009100723654E00041.png"\; state="\{\{state\}\}">t</figure-callout>\; </figure-callout>}}_{\mathrm{6,7}}=\frac{L_r{I}_o}{k_1{V}_{\mathrm{in}}}$ Formula 9

(8) switch mode 8[t ₇, t ₈].Referring to Figure 10, in this mode, the first insulating gate type field effect tube S1, the second insulating gate type field effect tube S2 and the 6th triode S6 conducting, v _Ab=V _In, load current flow over commutation diode DR1, former limit begins to provide energy to load.At this mode, v _Ab=V _In, i _pMaintain I _o/ k ₁, auxiliary transformer Tr2 continues to charge to clamp capacitor Cc.t ₈Clamp capacitor Cc charging constantly finishes.

(9) switch mode 9[t ₈, t ₉].Referring to Figure 11, in the mode, the first insulating gate type field effect tube S1, the second insulating gate type field effect tube S2 and the 6th triode S6 continue conducting, v thus _Ab=V _In, load current flows through the first rectifier diode DR1, and former limit begins to provide energy to load.At this mode, v _Ab=V _In, i _pMaintain I _o/ k ₁

(10) switch mode 10[t ₉, t ₁₀].Referring to Figure 12, at t ₉Constantly turn-off the first insulating gate type field effect tube S1, output current I _oReflex to the former limit of main transformer and the former limit exciting current of auxiliary transformer Tr2 and give first capacitor C 1 charging jointly, give the 4th capacitor C 4 discharges, v _C1Beginning is linear rises v _C4Linear decline, v _AbLinear decline.

$v_{C1}\left(t\right)=\frac{\frac{I_o}{{\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="H2009100723654E00011.png,H2009100723654E00042.png"\; state="\{\{state\}\}">k</figure-callout>}}_1}+I_{m\max }}{({\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="H2009100723654E00011.png,H2009100723654E00042.png"\; state="\{\{state\}\}">C</figure-callout>}}_1+C_4)}(t-t_9)$ Formula 10

$v_{C4}\left(t\right)=\frac{V_{\mathrm{in}}}{2}-\frac{\frac{I_o}{{\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="H2009100723654E00011.png,H2009100723654E00042.png"\; state="\{\{state\}\}">k</figure-callout>}}_1}+I_{m\max }}{({\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="H2009100723654E00011.png,H2009100723654E00042.png"\; state="\{\{state\}\}">C</figure-callout>}}_1+C_4)}(t-t_9)$ Formula 11

$v_{\mathrm{ab}}\left(t\right)=V_{\mathrm{in}}-\frac{\frac{I_o}{{\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="H2009100723654E00011.png,H2009100723654E00042.png"\; state="\{\{state\}\}">k</figure-callout>}}_1}+I_{m\max }}{({\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="H2009100723654E00011.png,H2009100723654E00042.png"\; state="\{\{state\}\}">C</figure-callout>}}_1+C_4)}(t-t_9)$ Formula 12

At t ₁₀Constantly, v _C1Rise to V _In/ 2, v _C4Drop to zero, v _AbDrop to V _In/ 2, the first insulating gate type field effect tube S1 is that no-voltage is turn-offed.In this mode, i _pMaintain I _o/ k ₁The duration of this mode is

$t_{\mathrm{9,10}}=\frac{V_{\mathrm{in}}({\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="H2009100723654E00011.png,H2009100723654E00042.png"\; state="\{\{state\}\}">C</figure-callout>}}_1+C_4)}{2(\frac{I_o}{{\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="H2009100723654E00011.png,H2009100723654E00042.png"\; state="\{\{state\}\}">k</figure-callout>}}_1}+I_{m\max })}$ Formula 13

(11) switch mode 11[t ₁₀, t ₁₁].Referring to Figure 13, t ₁₀Constantly, the conducting of the 8th diode D8 nature, to be seen as voltage be V because striding capacitance Css can be similar to _In/ 2 constant pressure source, therefore the voltage of the 4th insulating gate type field effect tube S4 is clamped to 0, v _Ab=V _In/ 2, i _pMaintain I _o/ k ₁, former limit continues to provide energy to load.

So far half work period finishes t ₁₁Constantly turn-off S2, begin half period down, identical with above-mentioned 11 mode, repeat no more.

The condition that ZVZCS of the present invention (zero-voltage and zero-current switch) realizes

During nominal load, because output current participates in the discharging and recharging of three level brachium pontis switching tube junction capacitance, ZVS more easily realizes.The first insulating gate type field effect tube S1 junction capacitance is connected with the second insulating gate type field effect tube S2 junction capacitance when unloaded, the 3rd insulating gate type field effect tube S3 junction capacitance is connected the back parallel connection with the 4th insulating gate type field effect tube S4 junction capacitance, and equivalent capacitance value is three level brachium pontis switching tube junction capacitance Cj.The ZVS of three level brachium pontis when realizing zero load must be at Dead Time t _DBIn finish to the discharging and recharging of three level brachium pontis switching tube junction capacitance, promptly

t _DB〉=C _jV _P2/ i _mFormula 14

I in the formula _mBe the former limit of auxiliary transformer exciting current, V _P2Be the auxiliary transformer original edge voltage, be 150V.The setting of Dead Time is subjected to the restriction of original edge voltage maximum duty cycle in addition.

The ZCS of converter realizes by resonant inductance and active clamp.In the former side ring stream incipient stage, open the 7th insulating gate type field effect tube S7, make clamp voltage V _CcReflex to the former limit of main transformer Tr1, affact on the resonant inductance, make main transformer Tr1 primary current i _pReturn zero, turn-off to realize no-voltage.Therefore the ON time of the 7th insulating gate type field effect tube S7 should be greater than primary current resetting time, promptly

${\mathrm{<figure-callout\; id="7"\; label="t\; S"\; filenames="H2009100723654E00011.png,H2009100723654E00041.png"\; state="\{\{state\}\}">t</figure-callout>}}_S\&GreaterEqual;\frac{L_r{I}_o}{{{\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="H2009100723654E00011.png,H2009100723654E00042.png"\; state="\{\{state\}\}">k</figure-callout>}}_1}^2{V}_{\mathrm{Cc}}}$ Formula 15

Simultaneously, t _S7Can not be too big, otherwise have more electric current by the 7th insulating gate type field effect tube S7, auxiliary rectifier circuit and clamp capacitor Cc, thus increase loss, lower efficiency.Therefore, under the prerequisite that guarantees hysteresis pipe ZCS, t _S7As far as possible little.In addition, in order to guarantee ZCS, sub-recombination time should be lacked more than or equal to IGBT at interval in the minimum dead band of hysteresis pipe.Maximum dead band is subject to the original edge voltage maximum duty cycle at interval.

Embodiment two: in conjunction with figure explanation present embodiment, present embodiment and embodiment one difference are that the main electrical parameter of converter of the present invention is: U _In=240V～320V, U _o=24V, output-current rating are 6A, and switching frequency is 50kHz.The model that the first insulating gate type field effect tube S1～the 4th insulating gate type field effect tube S4, the 7th insulating gate type field effect tube S7 adopt is IRF740, first capacitor C 1～the 4th capacitor C 4 is the switching tube junction capacitance, the model that the 5th triode S5～the 6th triode S6 adopts is HGTP20N60C3, clamp capacitor Cc=2.2 μ F, main transformer Tr1 no-load voltage ratio k ₁=63: 9, auxiliary transformer Tr2 no-load voltage ratio k ₂The model that=36: 12, the first rectifier diode DR1～the 4th rectifier diode DR4 selects for use is MUR1520, the first inductance L f1=50 μ H, filter capacitor Co=2200 μ F.

Figure 14 and Figure 15 are copped wave pipe S1 and driving and the drain-source voltage waveform of advance pipe S2 when nominal load.The amplitude of drain-source voltage is about 150V, is half of input voltage, and has dropped to zero before driving voltage rises.And in off-phases, its junction capacitance has limited the climbing of drain-source voltage, has realized ZVS.Figure 16 is driving and the primary current waveform of pipe S5 when nominal load that lag behind.When the drive signal trailing edge arrived, drain current had dropped to zero, and drain-source voltage raises gradually then, has realized zero-current switching; After the drive signal rising edge arrived, because the effect of resonant inductance, drain current rose gradually, has realized zero current turning-on, has solved the current tail phenomenon of IGBT.Figure 17 is two brachium pontis mid-point voltage V _AbWaveform, it comprises ± V _In, ± V _In/ 2 and 0 five kind of level.

When unloaded, copped wave pipe and advance pipe turn on and off simultaneously, and converter runs on two level modes, this moment, phase shifting angle reached maximum, the pipe nature that lags behind is realized ZCS, and copped wave pipe and advance pipe are finished discharging and recharging between junction capacitance by the former limit exciting current of auxiliary transformer, thereby realizes ZVS.Figure 18 has provided three level brachium pontis and two level brachium pontis mid-point voltage v _AbExperimental waveform, it only comprises ± V _InWith 0 three kinds of level, keep the stable of output voltage by it when unloaded.The driving and the drain-source voltage waveform of copped wave pipe and advance pipe when Figure 19 and Figure 20 are unloaded, this moment, copped wave pipe and advance pipe synchronization action were as can be seen from the figure realized ZVS.The transformer primary current only is an exciting current when unloaded, realizes ZCS naturally.Figure 21 is measured efficiency curve.As can be seen from the figure, efficient has reached 87.2% when nominal load.Other composition is identical with embodiment one with connected mode.

Claims (1)

1. the ZVZCS three-level DC-DC converter of wide load characteristic, it comprise first diode (D1) to the 8th diode (D8), first electric capacity (C1) to the 6th electric capacity (C6), a N type insulating gate type field effect tube (S1) to the 4th N type insulating gate type field effect tube (S4), the 5th NPN type triode (S5), the 6th NPN type triode (S6), striding capacitance (Css), resonant inductance (Lr), first inductance (Lf1), filter capacitor (C0), load resistance (R0), first rectifier diode (DR1), second rectifier diode (DR2) and main transformer (Tr1); One end of the 5th electric capacity (C5) links to each other with the drain electrode end of positive voltage terminal, a N type insulating gate type field effect tube (S1), the negative electrode of first diode (D1), an end of first electric capacity (C1), the collector terminal of the 5th NPN type triode (S5) and the negative electrode of the 5th diode (D5) simultaneously; The other end of the 5th electric capacity (C5) links to each other with the anode of the 7th diode (D7), the negative electrode of the 8th diode (D8) and an end of the 6th electric capacity (C6) simultaneously, and the other end of the 6th electric capacity (C6) links to each other with the source terminal of negative voltage side, the 4th N type insulating gate type field effect tube (S4), the anode of the 4th diode (D4), an end of the 4th electric capacity (C4), the emitter terminal of the 6th NPN type triode (S6) and the anode of the 6th diode (D6) simultaneously; The negative electrode of the 7th diode (D7) links to each other with an end of striding capacitance (Css), the source terminal of a N type insulating gate type field effect tube (S1), the drain electrode end of the 2nd N type insulating gate type field effect tube (S2), the anode of first diode (D1), the negative electrode of second diode (D2), the other end of first electric capacity (C1) and an end of second electric capacity (C2) simultaneously; The anode of the 8th diode (D8) links to each other with the other end of striding capacitance (Css), the source terminal of the 3rd N type insulating gate type field effect tube (S3), the drain electrode end of the 4th N type insulating gate type field effect tube (S4), the anode of the 3rd diode (D3), the negative electrode of the 4th diode (D4), an end of the 3rd electric capacity (C3) and the other end of the 4th electric capacity (C4) simultaneously; The source terminal of the 2nd N type insulating gate type field effect tube (S2) links to each other with the drain electrode end of the 3rd N type insulating gate type field effect tube (S3), the anode of second diode (D2), the negative electrode of the 3rd diode (D3), the other end of second electric capacity (C2), the other end of the 3rd electric capacity (C3) and the end of the same name of the former limit of main transformer (Tr1) winding simultaneously; The non-same polarity of the former limit of main transformer (Tr1) winding links to each other with an end of resonant inductance (Lr); The other end of resonant inductance (Lr) links to each other with the emitter terminal of the 5th NPN type triode (S5), the collector terminal of the 6th NPN type triode (S6), the anode of the 5th diode (D5) and the negative electrode of the 6th diode (D6) simultaneously; The non-same polarity of main transformer (Tr1) secondary winding links to each other with the anode of first rectifier diode (DR1), the end of the same name of main transformer (Tr1) secondary winding links to each other with the anode of second rectifier diode (DR2), the negative electrode of first rectifier diode (DR1) links to each other with an end of first inductance (Lf1) and the negative electrode of second rectifier diode (DR2) simultaneously, and the other end of first inductance (Lf1) links to each other with an end of filter capacitor (C0) and an end of load resistance (R0) simultaneously; The other end of filter capacitor (C0) links to each other with the other end of load resistance (R0) and the centre tap of main transformer (Tr1) secondary winding simultaneously; It is characterized in that it also comprises auxiliary transformer (Tr2), the 3rd rectifier diode (DR3), the 4th rectifier diode (DR4), second inductance (Lf2), the 7th N type insulating gate type field effect tube (S7) and clamp capacitor (Cc); The source terminal of the 7th N type insulating gate type field effect tube (S7) links to each other with the negative electrode of first rectifier diode (DR1), the negative electrode of second rectifier diode (DR2) and an end of first inductance (Lf1) simultaneously; The drain electrode end of the 7th N type insulating gate type field effect tube (S7) links to each other with an end of clamp capacitor (Cc) and an end of second inductance (Lf2) simultaneously, and the other end of second inductance (Lf2) links to each other with the negative electrode of the 3rd rectifier diode (DR3) and the negative electrode of the 4th rectifier diode (DR4) simultaneously; The anode of the 3rd rectifier diode (DR3) links to each other with the non-same polarity of auxiliary transformer (Tr2) secondary winding, and the anode of the 4th rectifier diode (DR4) links to each other with the end of the same name of auxiliary transformer (Tr2) secondary winding; The other end of clamp capacitor (Cc) links to each other with the other end of filter capacitor (C0) simultaneously, the centre tap of auxiliary transformer (Tr2) secondary winding, the centre tap of main transformer (Tr1) secondary winding and the other end of load resistance (R0) link to each other; The end of the same name of the former limit of auxiliary transformer (Tr2) winding links to each other with the other end of the 5th electric capacity (C5), an end of the 6th electric capacity (C6), the anode of the 7th diode (D7) and the negative electrode of the 8th diode (D8) simultaneously; The non-same polarity of the former limit of auxiliary transformer (Tr2) winding links to each other with the source terminal of the 2nd N type insulating gate type field effect tube (S2), the drain electrode end of the 3rd N type insulating gate type field effect tube (S3), the anode of second diode (D2), the negative electrode of the 3rd diode (D3), the other end of second electric capacity (C2), the other end of the 3rd electric capacity (C3) and the end of the same name of the former limit of main transformer (Tr1) winding simultaneously.

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