CN100499338C - Zero voltage zero current switch DC-DC converter - Google Patents

Abstract

A transfer DC-DC inverter of zero-voltage and zero-current type is prepared as forming booting DC-DC inverter by master switch tube A, power diode D and energy storage inductance L, realizing zero-voltage and zero-current on-off state of master switch tube A and realizing zero-current soft switch of auxiliary switch tubes B and C by utilizing auxiliary switch tube B to control auxiliary resonant network A and utilizing auxiliary switch tube C to control auxiliary resonant network B.

Description

A kind of zero-voltage zero-current shifts the DC-DC converter

Technical field

The present invention relates to a kind of zero-voltage zero-current and shift the DC-DC converter, specifically, relate to a kind of pwm converter of soft switch.

Background technology

The hard switching pwm converter is succinct with its topological structure, control mode is simple, operating frequency is constant and the output regulating characteristics is good and be used widely.In high pressure, high-power applications occasion, voltage, current stress that power device bears are big, and switching loss is big, and the electromagnetic interference brought of due to voltage spikes and current surge may influence the operate as normal of converter.Usually need to be aided with the absorption circuit with the switching device of larger capacity in traditional design, switching frequency is difficult to improve.For addressing these problems, many soft switch techniques have been proposed in recent years, both at home and abroad as resonant switch technology, zero switching technique and branch on zero technology etc.Wherein the branch on zero converter utilizes the resonant process of auxiliary switch control resonant element owing to adopt auxiliary network, has realized soft switch when keeping the pwm converter advantage, has reduced switching loss, becomes the research focus of field of power electronics.Although occur many novel circuit topologicals at present, but still exist some shortcomings,, auxiliary tube big as the switch tube voltage current stress can not realize that soft switch, main switch can not realize four zero, have big circulation energy etc.

Summary of the invention

The object of the present invention is to provide a kind of zero-voltage zero-current to shift the DC-DC converter.

The present invention constitutes like this: a kind of zero-voltage zero-current shifts the DC-DC converter, comprise by main switch (S1), the boost type DC-DC converter that power diode (D) and energy storage inductor (Lf) are formed, by the auxiliary resonant net 1 of first auxiliary switch (S2) control and the auxiliary resonant net of being controlled by second auxiliary switch (S3) 2, it is characterized in that: positive source is connected respectively to the collector electrode of main switch (S1) by energy storage inductor (Lf), one end of first electric capacity (C1), the collector electrode of second auxiliary switch (S3), the end of the same name of first inductance (L1), the non-same polarity of second inductance (L2), the anode of power diode (D); An other end of the emitter of main switch (S1), first electric capacity (C1) is connected to the negative terminal of power supply; The emitter of second auxiliary switch (S3) is connected with an end of the 4th inductance (Lr2) and the positive pole of the 3rd diode (D3) respectively, and the 4th inductance (Lr2) other end is connected to the negative terminal of power supply through second electric capacity (C2); The other end of first inductance (L1) links to each other with the positive pole of the 5th diode (D5), the 4th diode (D4) respectively through the 3rd inductance (Lr1), the negative pole of the 5th diode (D5) is connected respectively to the collector electrode of first auxiliary switch (S2), the negative pole of the 3rd diode (D3), and the emitter of first auxiliary switch (S2) links to each other with the negative terminal of power supply; The end of the same name of second inductance (L2) links to each other with the positive pole of second diode (D2), and the negative pole of power diode (D) is connected respectively to an end of negative pole, the 3rd electric capacity (C0) and the resistance (R0) of second diode (D2) and the 4th diode (D4); The 3rd electric capacity (C0) is connected with power supply negative terminal with the other end of resistance (R0); The base stage of main switch (S1), first auxiliary switch (S2), second auxiliary switch (S3) is connected respectively to three control circuits, described auxiliary resonant net 1 is made up of first inductance (L1), the 3rd inductance (Lr1), the 5th diode (D5), first auxiliary switch (S2) and first electric capacity (C1), be used to realize the no-voltage connection of main switch (S1), the coupling inductance that first inductance (L1) and second inductance (L2) are formed makes first auxiliary switch (S2) realize zero-current switching, has also reduced the current stress of first auxiliary switch (S2); Described auxiliary resonant net 2 is made up of the 4th inductance (Lr2), second auxiliary switch (S3) and second electric capacity (C2) and main switch (S1), be used to realize the zero current break-make of the zero-current switching and second auxiliary switch (S3) of main switch (S1), the resonant network that the 4th inductance (Lr2), second electric capacity (C2), the 3rd diode (D3) and first auxiliary switch (S2) are formed is used to make second electric capacity (C2) reversed polarity, for the work of auxiliary resonant net 2 creates conditions.

The present invention is the soft switch DC-DC converter circuit topology that a kind of zero-voltage zero-current shifts, and it has realized the soft switch of whole main and auxiliary switches by adopting two auxiliary resonance branch roads.Because main switch (S1) has been realized four zero, eliminated voltage and current the overlapping phenomenon, reduced switching loss; Four slopes have reduced

,

, switch stress reduces, and has also solved the EMI problem that the hard switching pwm converter causes, the reverse-recovery problems of diode simultaneously.In the loading range of broad, no-voltage, Zero Current Switch condition all can be guaranteed.This DC-DC converter is because main switch and auxiliary switch have all been realized the zero current break-make, and all available IGBT of main switch and auxiliary switch is used for high voltage, high-power applications occasion as switching device.

Description of drawings

Fig. 1 is soft switch circuit figure of the present invention;

Fig. 2 is the equivalent electric circuit of pattern 1 operating state of the present invention;

Fig. 3 is the equivalent electric circuit of pattern 2 operating states of the present invention;

Fig. 4 is the equivalent electric circuit of mode 3 operating state of the present invention;

Fig. 5 is the equivalent electric circuit of pattern 4 operating states of the present invention;

Fig. 6 is the equivalent electric circuit of pattern 5 operating states of the present invention;

Fig. 7 is the equivalent electric circuit of pattern 6 operating states of the present invention;

Fig. 8 is the equivalent electric circuit of mode 7 operating state of the present invention;

Fig. 9 is the equivalent electric circuit of pattern 8 operating states of the present invention.

Embodiment

The present invention relates to a kind of zero-voltage zero-current and shift the DC-DC converter, comprise by main switch (S1), the boost type DC-DC converter that power diode (D) and energy storage inductor (Lf) are formed, by the auxiliary resonant net 1 of first auxiliary switch (S2) control and the auxiliary resonant net of being controlled by second auxiliary switch (S3) 2, it is characterized in that: positive source is connected respectively to the collector electrode of main switch (S1) by energy storage inductor (Lf), one end of first electric capacity (C1), the collector electrode of second auxiliary switch (S3), the end of the same name of first inductance (L1), the non-same polarity of second inductance (L2), the anode of power diode (D); An other end of the emitter of main switch (S1), first electric capacity (C1) is connected to the negative terminal of power supply; The emitter of second auxiliary switch (S3) is connected with an end of the 4th inductance (Lr2) and the positive pole of the 3rd diode (D3) respectively, and the 4th inductance (Lr2) other end is connected to the negative terminal of power supply through second electric capacity (C2); The other end of first inductance (L1) links to each other with the positive pole of the 5th diode (D5), the 4th diode (D4) respectively through the 3rd inductance (Lr1), the negative pole of the 5th diode (D5) is connected respectively to the collector electrode of first auxiliary switch (S2), the negative pole of the 3rd diode (D3), and the emitter of first auxiliary switch (S2) links to each other with the negative terminal of power supply; The end of the same name of second inductance (L2) links to each other with the positive pole of second diode (D2), and the negative pole of power diode (D) is connected respectively to an end of negative pole, the 3rd electric capacity (C0) and the resistance (R0) of second diode (D2) and the 4th diode (D4); The 3rd electric capacity (C0) is connected with power supply negative terminal with the other end of resistance (R0); The base stage of main switch (S1), first auxiliary switch (S2), second auxiliary switch (S3) is connected respectively to three control circuits, described auxiliary resonant net 1 is made up of first inductance (L1), the 3rd inductance (Lr1), the 5th diode (D5), first auxiliary switch (S2) and first electric capacity (C1), be used to realize the no-voltage connection of main switch (S1), the coupling inductance that first inductance (L1) and second inductance (L2) are formed makes first auxiliary switch (S2) realize zero-current switching, has also reduced the current stress of first auxiliary switch (S2); Described auxiliary resonant net 2 is made up of the 4th inductance (Lr2), second auxiliary switch (S3) and second electric capacity (C2) and main switch (S1), be used to realize the zero current break-make of the zero-current switching and second auxiliary switch (S3) of main switch (S1), the resonant network that the 4th inductance (Lr2), second electric capacity (C2), the 3rd diode (D3) and first auxiliary switch (S2) are formed is used to make second electric capacity (C2) reversed polarity, for the work of auxiliary resonant net 2 creates conditions.

Above-mentioned DC-DC converter, as shown in Figure 2, its operation principle is such:

To simplify the analysis, suppose that all components and parts all are desirable in the circuit, input filter inductance L _fEnough big, use constant-current source I _iReplace, export the 3rd capacitor C ₀Enough big, use constant pressure source V ₀Replace.If t=t ₀In the past, main switch S ₁With auxiliary switch S ₂, S ₃All turn-off second capacitor C ₂Voltage be V _C2maxEight kinds of operational modes are arranged, as shown in Figure 2: (1) pattern 1 (t in the switch periods ₀～t ₁)

t ₀The time, the first auxiliary tube S ₂Zero current passing has two kinds of working conditions:

(a) the 3rd inductance L _R1Electric current is charged to by zero line

$i_{\mathrm{Lr}1}=i_{\mathrm{Lr}2}=\frac{I_i}{2},$ The rectifier diode current i _D=I _i-i _L1-i _L2=0, rectifier diode D zero-current switching, linear-charging time $t_{01}=\frac{I_i{L}_{r1}}{{2V}_0}.$

(b) L _R2Pass through S ₂, D ₃With C ₂Resonance takes place, and has:

$i_{\mathrm{Lr}2}=-\frac{V_{C2\max }}{Z_{r2}}\sin {\mathrm{\ω}}_2(t-t_4)---\left(1\right)$

u _c2＝V _C2maxcosω ₂(t-t ₄)(2)

In the formula, ${\mathrm{\ω}}_2=\frac{1}{\sqrt{L_{r2}{C}_2}},$ $Z_{r2}=\sqrt{\frac{L_{r2}}{C_2}}.$

Process

Stop resonance behind the harmonic period, this section period may be extended to pattern 2 and mode 3.

Pattern 2 (t ₁～t ₂)

t ₁The time i _D=0, rectifier diode D turn-offs, L _R1Pass through S ₂With C ₁Resonance takes place, and has:

$i_{\mathrm{Lr}1}=\frac{1}{2}{I}_i+\frac{V_0}{Z_{r1}}\sin {\mathrm{\ω}}_1(t-t_1)---\left(3\right)$

$U_{C1}=\frac{1}{2}{V}_0[1+\cos {\mathrm{\ω}}_1(t-t_1)]---\left(4\right)$

In the formula, ${\mathrm{\ω}}_1=\frac{2}{\sqrt{L_{r1}{C}_1}},$ $Z_{r1}=2\sqrt{\frac{L_{r1}}{C_1}}.$

C ₁Voltage u _C1Reduce gradually, simultaneously coupling inductance secondary current i _L2Pass through D ₂Flow to load, auxiliary switch bears less current stress, this time in stage $t_{12}=\frac{\mathrm{\π}}{{\mathrm{\ω}}_1}=\frac{\mathrm{\π}\sqrt{L_{r1}{C}_1}}{2}.$

(3) mode 3 (t ₂～t ₃)

t ₂The time, u _C1=0, anti-and diode D in the main switch body ₁Main switch S is given in conducting this moment ₁Add trigger impulse, S ₁No-voltage is connected.The 3rd inductance L _R1Electric current $i_{\mathrm{Lr}1}=\frac{1}{2}{I}_i-\frac{V_0}{L_{r1}}(t-t_2),$ The 3rd inductance L _R1Middle energy back is to load, and main switch S is flow through in the linear discharge of resonant inductance ₁Electric current is linear to increase S ₁For zero current is connected.When $t_{23}=\frac{I_i{L}_{r1}}{{2V}_0}$ The time, i _Lr1=0, the first auxiliary tube S ₂Current i _S2=0, after this to the second auxiliary tube S ₃Open the predecessor and when carve the shutoff first auxiliary switch S ₂All can realize the first auxiliary tube S ₂Zero-current switching.

(4) pattern 4 (t ₃～t ₄)

t ₃The time, main switch S ₁Drain-source current reach filter inductance L _fElectric current I _i, circuit returns to traditional PWM operating state.

(5) pattern 5 (t ₄～t ₅)

t ₄Before, main switch S ₁Conducting, C ₂Voltage is charged to-V _C2maxt ₄The time, the second auxiliary tube S ₃Zero current passing, L _R2Pass through S ₁, S ₃With C ₂Resonance takes place.Have in this time period:

$i_{\mathrm{Lr}2}=\frac{V_{C2\max }}{Z_{r2}}\sin {\mathrm{\ω}}_2(t-t_4)---\left(5\right)$

u _c2＝-V _C2maxcosω ₂(t-t ₄)(6)

Resonance current i _Lr2Force main switch S ₁Drain-source current i _S1=I _i-i _Lr2Reduce with sinusoidal rule, work as i _Lr2Resonance is to equaling input current I _iThe time, main switch S ₁In electric current drop to zero.Afterwards, i _Lr2Continue resonance and rise S ₁It is negative that the place branch current becomes, S ₁Anti-and diode current flow, process

Behind the harmonic period, $i_{\mathrm{Lr}2}=\frac{V_{C2\max }}{Z_{r2}}$ Reach maximum, resonance descends then.Work as i _Lr2Resonance drops to and equals I once more _iThe time, S ₁Anti-and diode D ₁Electric current drops to zero.At S ₁Anti-and diode D ₁Conduction period, turn-off main switch S ₁Can realize that zero-voltage zero-current turn-offs.This section time interval $t_{45}=\frac{\mathrm{\π}}{2}\sqrt{L_{r2}{C}_2}.$

(6) pattern 6 (t ₅～t ₆)

Main switch S ₁Have no progeny in the pass, L _R2With C ₂, C ₁Continue to take place resonance, first capacitor C ₁Voltage u _C1Increase C gradually by zero beginning ₂Voltage also continues to increase.Work as u _C1=V ₀The time, rectifier diode D conducting.

(7) mode 7 (t ₆～t ₇)

After the rectifier diode D conducting, L _R2With C ₂Continue resonance, this time be interrupted and have:

$i_{\mathrm{Lr}2}=\sqrt{{I_{\mathrm{LM}}}^2+{\left(\frac{V_{\mathrm{CM}}-V_0}{Z_{r2}}\right)}^2}\cos [{\mathrm{\ω}}_2(t-t_6)+\mathrm{\θ}]---\left(7\right)$

$U_{C2}=V_0+\sqrt{{(V_{\mathrm{CM}}-V_0)}^2+I_{\mathrm{LM}}^2{Z}_{r2}^2}\sin [{\mathrm{\ω}}_2(t-t_6)+\mathrm{\θ}]---\left(8\right)$

In the formula, $\mathrm{\θ}={\tan }^{-1}\frac{V_{\mathrm{CM}}-V_0}{Z_{r2}{I}_{\mathrm{LM}}},$ I _LM＝i _Lr2(t ₆)，V _CM＝u _c2(t ₆)

As resonance current i _Lr2When dropping to zero, resonance potential u _C2Reach maximum $V_{C2\max }=V_0+\sqrt{{(V_{\mathrm{CM}}-V_0)}^2+I_{\mathrm{LM}}^2{Z}_{r2}^2},$ This time period finishes, $t_{67}=(\frac{\mathrm{\π}}{2}-\mathrm{\θ})\sqrt{L_{r2}{C}_2}.$

(8) pattern 8[t ₇～t ₈(t ₀)]

t ₇The time, L _R2With C ₂Resonance stop u _C2Voltage remains on maximum V _C2max, i _Lr2=0, flow through the second auxiliary tube S ₃Drain-source current be zero, after this to the first auxiliary tube S ₂When open the predecessor carves and all can make the second auxiliary tube S ₃Zero-current switching.t ₇Rectifier diode D conducting fully later on, circuit is got back to traditional PWM operating state again.t ₈The time the first auxiliary tube S ₂Conducting, circuit repeat the work of one-period again.

By above analysis as can be known, realize main switch ZVS, key is pattern 1 and pattern 2.Pattern 1 has realized that the Zero-current soft of output rectifier diode D turn-offs, and the shutoff of D is L _R1And C ₁Resonance created condition.In pattern 2, realize S ₁No-voltage is connected and must be guaranteed u _C1At main switch S ₁Open preceding from V ₀Resonance need meet the following conditions to zero:

$T_{2\mathrm{on}}\≥t_{01}+t_{12}=\frac{I_i{L}_{r1}}{{2V}_0}+\frac{\mathrm{\π}\sqrt{L_{r1}{C}_1}}{2}---\left(9\right)$

In the formula, T _2onBe auxiliary tube S ₂Pulse duration.

Simultaneously, in order to make the second auxiliary tube S ₂Realize that zero-current switching also must satisfy following condition:

$T_{2\mathrm{on}}\≥t_{01}+t_{12}+t_{23}=\frac{I_i{L}_{r1}}{V_0}+\frac{\mathrm{\π}\sqrt{L_{r1}{C}_1}}{2}---\left(10\right)$

$T_{2\mathrm{on}}\≥\frac{\mathrm{\π}\sqrt{L_{r2}{C}_2}}{2}---\left(11\right)$

Obviously, make main switch S ₁The realization no-voltage is connected, the second auxiliary tube S ₂Also realize zero-current switching, must satisfy formula (10) and formula (11) simultaneously.

At the first auxiliary tube S ₂Conduction period, there are two branch currents to flow through the first auxiliary tube S ₂, one from the 3rd inductance L _R1Electric current, another is from the 4th inductance L _R2Electric current.During this period, L _R2, C ₂Resonance branch road u _C2By V _C2maxBecome-V _C2max, i _Lr2Return 0 from 0 resonance to maximum, keep the resonance value afterwards until the second auxiliary tube S ₃Open-minded, be main switch S ₁Zero-current switching creates conditions.

The key that realizes main switch ZCS is pattern 5, utilizes L _R2, C ₂The shunting action of resonant tank makes the electric current of main switch shift i _S1=I _i-i _Lr2, resonance branch current i _Lr2Increase the main switch current i gradually _S1Reduce gradually, until i _S1Realized zero-current switching at=0 o'clock.At this stage L _R2, C ₂The prerequisite that resonance is taken place is to give capacitor C ₂Give certain initial voltage, and main switch realizes that zero-current switching must meet the following conditions:

$i_{\mathrm{Lr}2\max }=\left|\frac{V_{C2\max }}{Z_{r2}}\right|\≥I_i---\left(12\right)$

Make the second auxiliary tube S ₃Realize that also zero-current switching also must satisfy:

T _3on≥t ₄₅+t ₅₆+t ₆₇(13)

T in the formula _3onBe auxiliary tube S ₃Pulse duration.

Claims (1)

1, a kind of zero-voltage zero-current shifts the DC-DC converter, comprise by main switch (S1), the boost type DC-DC converter that power diode (D) and energy storage inductor (Lf) are formed, by the auxiliary resonant net 1 of first auxiliary switch (S2) control and the auxiliary resonant net of being controlled by second auxiliary switch (S3) 2, it is characterized in that: positive source is connected respectively to the collector electrode of main switch (S1) by energy storage inductor (Lf), one end of first electric capacity (C1), the collector electrode of second auxiliary switch (S3), the end of the same name of first inductance (L1), the non-same polarity of second inductance (L2), the anode of power diode (D); An other end of the emitter of main switch (S1), first electric capacity (C1) is connected to the negative terminal of power supply; The emitter of second auxiliary switch (S3) is connected with an end of the 4th inductance (Lr2) and the positive pole of the 3rd diode (D3) respectively, and the 4th inductance (Lr2) other end is connected to the negative terminal of power supply through second electric capacity (C2); The other end of first inductance (L1) links to each other with the positive pole of the 5th diode (D5), the 4th diode (D4) respectively through the 3rd inductance (Lr1), the negative pole of the 5th diode (D5) is connected respectively to the collector electrode of first auxiliary switch (S2), the negative pole of the 3rd diode (D3), and the emitter of first auxiliary switch (S2) links to each other with the negative terminal of power supply; The end of the same name of second inductance (L2) links to each other with the positive pole of second diode (D2), and the negative pole of power diode (D) is connected respectively to an end of negative pole, the 3rd electric capacity (C0) and the resistance (R0) of second diode (D2) and the 4th diode (D4); The 3rd electric capacity (C0) is connected with power supply negative terminal with the other end of resistance (R0); The base stage of main switch (S1), first auxiliary switch (S2), second auxiliary switch (S3) is connected respectively to three control circuits, described auxiliary resonant net 1 is made up of first inductance (L1), the 3rd inductance (Lr1), the 5th diode (D5), first auxiliary switch (S2) and first electric capacity (C1), be used to realize the no-voltage connection of main switch (S1), the coupling inductance that first inductance (L1) and second inductance (L2) are formed makes first auxiliary switch (S2) realize zero-current switching, has also reduced the current stress of first auxiliary switch (S2); Described auxiliary resonant net 2 is made up of the 4th inductance (Lr2), second auxiliary switch (S3) and second electric capacity (C2) and main switch (S1), be used to realize the zero current break-make of the zero-current switching and second auxiliary switch (S3) of main switch (S1), the resonant network that the 4th inductance (Lr2), second electric capacity (C2), the 3rd diode (D3) and first auxiliary switch (S2) are formed is used to make second electric capacity (C2) reversed polarity, for the work of auxiliary resonant net 2 creates conditions.

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