CN104967329A - Switch coupled inductor-type dual-bootstrap three-level zeta converter - Google Patents

Abstract

The invention discloses a switch coupled inductor-type dual-bootstrap three-level zeta converter, which relates to a high-gain DC-DC converter and aims at solving the problem that the voltage gain of the traditional DC-DC converter is limited by a circuit duty cycle. A coupled inductor element is applied to the high-gain DC-DC converter. A variable, that is, a coupled inductor turn ratio, is introduced in the DC-DC converter, limitation on the voltage gain in the circuit by the duty cycle ratio value in the DC-DC converter is fully solved, higher performance requirements on the DC converter by renewable energy equipment and the like can be better met, certain application situations with a high voltage gain can be met, and requirements on the voltage-resisting ability of a switching device by the circuit are reduced while the voltage gain is enhanced.

Description

Switch couples inductive type dual bootstrap three level zeta converter

Technical field

The present invention relates to high-gain DC-DC converter.

Background technology

The DC-DC converter applied in every field mostly at present is the circuit structure of two level, and by contrast, the circuit topology of the DC-DC converter of three level shows its distinctive advantage and feature.Three-level DC-DC converter and two level circuit structures are when the identical voltage gain had, and the voltage stress being arranged in switching tube and diode constant power switching device two ends is but only the half of two level-conversion circuits.Meanwhile, when the switching frequency of drive singal is identical, when the pulsation of inductive current pulsation and capacitance voltage is also identical, the value of the energy-storage travelling wave tube of inductance and electric capacity etc. also can reduce greatly than in former two level circuits.

Due to the advantage that three-level DC-DC converter circuit structure shows, increasing scholar expands a series of research to the various aspects of its circuit topology, service behaviour etc.Wherein, two level DC-DC converters of traditional structure are all converted to three-level DC-DC converter for being reduced in the voltage stress at switching tube and diode constant power switching device two ends and reducing the size of the filtering devices such as inductance capacitance by scholar according to the shift theory of three-level converter.But, because three-level DC-DC converter has identical voltage conversion ratio with two level circuits, so, convert via two common level circuits the voltage conversion ratio that the three-level DC-DC converter obtained can not reach very high.

Nowadays, the DC-DC converter with high gain voltage translation function has generally been applied in the battery backup system in electric automobile, cleaning cart and regenerative resource and uninterrupted power supply, therefore also gradually become the focus that Chinese scholars competitively study.In order to realize the high voltage conversion ratio of DC-DC converter, usually in traditional DC-DC converter, we have to duty ratio to be chosen for the situation of a relative extreme, and we select duty ratio to be less than 0.1 or be greater than 0.9 usually.And when the value of duty ratio is when extreme like this, will be very disadvantageous to the efficiency of the electric energy conversion in circuit.In addition, the method being promoted voltage gain in circuit by normal shock and flyback is not requiring that in the industrial equipment of isolating, the use of transformer can increase volume, increasing expense undoubtedly, also will reduce the efficiency of electric energy conversion simultaneously.Article proposes the form by cascaded inverters, obtains desired voltage conversion ratio.Cascade circuit is connected multiple identical DC-DC converter, so the efficiency of total efficiency in circuit after cascade and each independent circuit is identical, although the higher voltage conversion ratio of circuit realiration in this way, the use of cascade converter only increases expense and loss undoubtedly.Scholars generally notice, the voltage gain changed efficiently in circuit if think, the topological structure of original circuit changes, and then the lifting realizing its voltage gain is very necessary and desirable, therefore, switched inductors and Switch capacitor structure unit are also proposed to be applied in the high-gain DC-DC converter of non-isolation type by scholars in the recent period.

The change of circuit topological structure realizes a kind of good method raising DC-DC converter voltage gain beyond doubt, converter voltage gain can be made to get a promotion, but be only still cannot to solve in DC converter voltage gain in this way to the dependence of circuit duty ratio value.

Summary of the invention

The object of the invention is to solve traditional DC-DC converter, the size of its voltage gain, by the problem of circuit duty-cycle limit, provides a kind of switch couples inductive type dual bootstrap three level zeta converter.

Switch couples inductive type dual bootstrap three level zeta converter of the present invention, comprises electric capacity C ₀, electric capacity C ₁, electric capacity C ₂, electric capacity C ₃, electric capacity C ₄, electric capacity C ₅, electric capacity C ₆, diode D ₁, diode D ₂, diode D ₃, diode D ₄, diode D ₅, diode D ₆, diode D ₇, diode D ₈, diode D ₉, diode D ₁₀, inductance L ₀, coupling inductance L ₁, coupling inductance L ₂, resistance R ₀, main switch S ₁, main switch S ₂with auxiliary switch S ₀, described main switch S ₁, main switch S ₂with auxiliary switch S ₀metal-oxide-semiconductor is all adopted to realize;

Electric capacity C ₁with electric capacity C ₂series connection, forms series arm, and one end of this series arm connects main switch S ₁positive pole, the other end of series arm connects main switch S ₂negative pole, the two ends of the first series arm are as the input of described converter;

Form coupling inductance L ₁two inductance reversal connections, coupling inductance L ₁same Name of Ends connect diode D respectively ₇two ends, diode D ₇anode also connect main switch S simultaneously ₁negative pole, coupling inductance L ₁another terminals of former end connect diode D ₈anode, coupling inductance L ₁another terminals of secondary end connect diode D ₁anode, diode D ₁negative electrode connect main switch S ₂positive pole;

Diode D ₈negative electrode connect electric capacity C ₃one end, electric capacity C ₃the other end connect diode D simultaneously ₃negative electrode and auxiliary switch S ₀positive pole, diode D ₃anode connect main switch S ₁negative pole;

Auxiliary switch S ₀negative pole connect electric capacity C simultaneously ₄one end and diode D ₄anode, C ₄the other end connect diode D ₉anode, diode D ₄negative electrode connect main switch S ₂positive pole;

Form coupling inductance L ₂two inductance reversal connections, coupling inductance L ₂same Name of Ends connect diode D respectively ₉two ends, diode D ₉anode also connect diode D simultaneously ₂negative electrode, diode D ₂anode connect main switch S ₁negative pole, coupling inductance L ₂another terminals of former end connect diode D ₁₀anode, coupling inductance L ₂another terminals of secondary end connect diode D ₁₀anode, diode D ₁₀negative electrode also connect main switch S simultaneously ₂positive pole;

Diode D ₂anode also connect electric capacity C simultaneously ₅one end, diode D ₁₀negative electrode also connect electric capacity C simultaneously ₆one end, electric capacity C ₅the other end connect diode D simultaneously ₅negative electrode and inductance L ₀one end, diode D ₅anode connect diode D ₆negative electrode, diode D ₆anode connect electric capacity C simultaneously ₆the other end and electric capacity C ₀one end, electric capacity C ₀the other end connect inductance L ₀the other end, electric capacity C ₀two ends as the output of described converter;

Diode D ₅with diode D ₆common port connect electric capacity C ₁with electric capacity C ₂common port.

Coupling Induction is applied in high-gain DC-DC converter by the present invention.The introducing of this variable of coupling inductance turn ratio in DC-DC converter, solve duty ratio value in DC-DC converter fully and, to the restriction of voltage gain in circuit, better meet renewable energy source device etc. to requirement more high performance in DC converter.

Accompanying drawing explanation

Fig. 1 is the circuit topology figure of the switch couples inductive type dual bootstrap three level zeta converter described in execution mode one;

Fig. 2 is when in execution mode one, converter is in mode 1 or mode 3, the current flow paths of circuit;

Fig. 3 is when in execution mode one, converter is in mode 2, the current flow paths of circuit;

Fig. 4 is when in execution mode one, converter is in mode 4, the current flow paths of circuit;

Fig. 5 is the current waveform figure that in execution mode two, Matlab emulates two former ends of coupling inductance and the secondary end obtained, wherein i ₁represent the electric current of former end, i ₂the electric current of vice end;

Fig. 6 is that in execution mode two, Matlab emulates the electric capacity C obtained ₅the voltage oscillogram at two ends;

Fig. 7 is the voltage oscillogram that in execution mode two, Matlab emulates the converter output terminal obtained;

Fig. 8 is the current waveform figure of actual two the former ends of coupling inductance recorded and secondary end in execution mode two;

Fig. 9 is voltage oscillogram and the electric capacity C of the actual converter output terminal recorded in execution mode two ₅the voltage waveform at two ends.

Embodiment

Embodiment one: composition graphs 1 to Fig. 4 illustrates present embodiment, the switch couples inductive type dual bootstrap three level zeta converter described in present embodiment, comprises electric capacity C ₀, electric capacity C ₁, electric capacity C ₂, electric capacity C ₃, electric capacity C ₄, electric capacity C ₅, electric capacity C ₆, diode D ₁, diode D ₂, diode D ₃, diode D ₄, diode D ₅, diode D ₆, diode D ₇, diode D ₈, diode D ₉, diode D ₁₀, inductance L ₀, coupling inductance L ₁, coupling inductance L ₂, resistance R ₀, main switch S ₁, main switch S ₂with auxiliary switch S ₀, described main switch S ₁, main switch S ₂with auxiliary switch S ₀metal-oxide-semiconductor is all adopted to realize;

Electric capacity C ₁with electric capacity C ₂series connection, forms series arm, and one end of this series arm connects main switch S ₁positive pole, the other end of series arm connects main switch S ₂negative pole, the two ends of the first series arm are as the input of described converter;

Form coupling inductance L ₁two inductance reversal connections, coupling inductance L ₁same Name of Ends connect diode D respectively ₇two ends, diode D ₇anode also connect main switch S simultaneously ₁negative pole, coupling inductance L ₁another terminals of former end connect diode D ₈anode, coupling inductance L ₁another terminals of secondary end connect diode D ₁anode, diode D ₁negative electrode connect main switch S ₂positive pole;

Diode D ₈negative electrode connect electric capacity C ₃one end, electric capacity C ₃the other end connect diode D simultaneously ₃negative electrode and auxiliary switch S ₀positive pole, diode D ₃anode connect main switch S ₁negative pole;

Auxiliary switch S ₀negative pole connect electric capacity C simultaneously ₄one end and diode D ₄anode, C ₄the other end connect diode D ₉anode, diode D ₄negative electrode connect main switch S ₂positive pole;

Form coupling inductance L ₂two inductance reversal connections, coupling inductance L ₂same Name of Ends connect diode D respectively ₉two ends, diode D ₉anode also connect diode D simultaneously ₂negative electrode, diode D ₂anode connect main switch S ₁negative pole, coupling inductance L ₂another terminals of former end connect diode D ₁₀anode, coupling inductance L ₂another terminals of secondary end connect diode D ₁₀anode, diode D ₁₀negative electrode also connect main switch S simultaneously ₂positive pole;

Diode D ₂anode also connect electric capacity C simultaneously ₅one end, diode D ₁₀negative electrode also connect electric capacity C simultaneously ₆one end, electric capacity C ₅the other end connect diode D simultaneously ₅negative electrode and inductance L ₀one end, diode D ₅anode connect diode D ₆negative electrode, diode D ₆anode connect electric capacity C simultaneously ₆the other end and electric capacity C ₀one end, electric capacity C ₀the other end connect inductance L ₀the other end, electric capacity C ₀two ends as the output of described converter;

Diode D ₅with diode D ₆common port connect electric capacity C ₁with electric capacity C ₂common port.

Operation principle:

As main switch S ₁with main switch S ₂conducting, auxiliary switch S ₀during shutoff, the former end effect of two coupling inductances, is charged by power supply, and the voltage of two former ends of coupling inductance is the voltage U of power supply _i, according to the former secondary terminal voltage relation ratio of coupling inductance, the voltage that can obtain the pair end of two coupling inductances is nU _i, wherein no-load voltage ratio factor of n=N ₂/ N ₁, N ₁for coupling inductance L ₁with coupling inductance L ₂the number of turn of former end-coil, N ₂for coupling inductance L ₁with coupling inductance L ₂the number of turn of secondary end-coil.And as main switch S ₁with main switch S ₂in a shutoff, another conducting and auxiliary switch S ₀during conducting, the pair end effect of two coupling inductances, two secondary ends form discharge loop.

In this converter, when power supply charges to inductance, capacity cell, the effect due to coupling inductance makes the voltage of coupling inductance pair end be nU _i, compared to non-coupled inductive circuit before, voltage is promoted to original n doubly.Therefore, when the calculating voltage gain of circuit voltage-second balance, the voltage gain of this circuit is improved due to the introducing of no-load voltage ratio factor of n in Coupled Inductor Circuit.Meanwhile, compared with two traditional level circuits, the voltage stress of the device such as switching tube, diode in this three level zeta converter significantly reduces, and the realization for high gain boost circuit provides larger feasibility.

Under switch mode effect shown in table 1, the current flow paths of this circuit as shown in Figures 2 to 4.

The on off state of table 1 switch couples inductive type dual bootstrap three level zeta converter

The circuit mode 1 of this switch couples inductive type dual bootstrap three level zeta converter is identical with the type of action of mode 3 breaker in middle, and in circuit, the circulation path of electric current is also consistent.When on off state is in mode 1 and mode 3 time, main switch S ₁with main switch S ₂conducting, auxiliary switch S ₀turn off, in circuit, the circulation path of electric current as shown in Figure 2.Now the former end of two coupling inductances is in parallel connection, and power supply is to electric capacity C ₃with electric capacity C ₄charge, coupling inductance L ₁the voltage of former end and secondary end uses u respectively ₁₁and u ₁₂represent, coupling inductance L ₂the voltage of former end and secondary end uses u respectively ₂₁and u ₂₂represent, then have

u ₁₁＝u ₂₁＝U _i(7)

u _L0＝U _i+2u _c-U _o(8)

Wherein, U _orepresent the voltage of converter output terminal, u _crepresent electric capacity C ₅with electric capacity C ₅the voltage at two ends, u _l0represent inductance L ₀the voltage at two ends;

Can obtain the secondary terminal voltage of coupling inductance according to the voltage relationship at the former secondary two ends of coupling inductance is

u ₁₂＝u ₂₂＝nU _i(9)

When switch is in mode 2, main switch S ₁with auxiliary switch S ₀conducting, main switch S ₂turn off, now in circuit, type of action is as shown in Figure 3.Under this mode, the pair end of two coupling inductances is by auxiliary switch S ₀effect be in series connection, now have

$u_{12}=u_{22}=\frac{5U_i}{4}-\frac{u_c}{2}---\left(10\right)$

$u_{L0}=\frac{U_i}{2}+u_c-U_o---\left(11\right)$

Further, can obtain the secondary terminal voltage of coupling inductance according to the voltage relationship at the former secondary two ends of coupling inductance is

$u_{12}=u_{22}=\frac{1}{n}(\frac{5U_i}{4}-\frac{u_c}{2})---\left(12\right)$

When on-off action is in mode 4, main switch S ₁shutoff, main switch S ₂with auxiliary switch S ₀conducting, now in circuit, the circulation path of electric current is as shown in Figure 4.Circuit is when this mode effect, and the voltage stress at inductance two ends is identical with mode 2.

The circuit duty ratio supposing this switch couples inductive type dual bootstrap three level zeta converter is D, then can derive and draw in one-period T, and the action time of mode 1 and mode 3 is the action time of mode 2 and mode 4 is (1-D) T.In this circuit, the type of action of mode 1 and mode 3 is completely the same, and mode 2 and mode 4 are according to the symmetry of circuit, and type of action is also basically identical.Therefore, circuit reduction, when according to the calculating voltage gain of voltage-second balance principle, can be two kinds of effect mode, then have by this circuit

$U_i(D-\frac{1}{2})+\frac{1}{n}(\frac{5U_i}{4}-\frac{u_c}{2})(1-D)=0---\left(13\right)$

$(U_i+2u_c-U_o)(D-\frac{1}{2})-(\frac{U_i}{2}+u_c-U_o)(1-D)=0---\left(14\right)$

By equation (13), (14) simultaneous solution must the voltage gain of this switch couples inductive type dual bootstrap three level zeta converter be

$\frac{U_o}{U_i}=\frac{D}{1-D}\left(n\right(4D-2)+6(1-D\left)\right)---\left(15\right)$

Same, can obtain at main switch S ₁and S ₂and diode D ₅and D ₆when turning off, the voltage stress at two ends is

$u_{s1}=u_{s2}=u_{D5}=u_{D6}=\frac{U_o}{2D}---\left(16\right)$

U _s1and u _s2be respectively main switch S ₁and S ₂the voltage stress at two ends; u _d5and u _d6be respectively diode D ₅and D ₆the voltage stress at two ends.

In addition, at electric capacity C ₅with electric capacity C ₆be filter capacitor, the voltage stress at two ends is as shown in formula (17).

$u_c=\frac{1}{2}(\frac{U_o}{D}-U_i)---\left(17\right)$

From formula (15), in this switch couples inductive type dual bootstrap three level zeta converter, voltage gain formula introduces no-load voltage ratio factor of n, make voltage gain in this circuit no longer only be limited to choosing of duty cycle parameters, the voltage gain of this circuit have also been obtained further rising simultaneously.

The circuit topological structure that present embodiment proposes, the basis of traditional circuit adds special coupling inductance construction unit and boostrap circuit structure, improves the voltage gain of circuit greatly and reduce the dependence of voltage transitions comparison duty ratio value in circuit.Circuit is reduced while booster tension gain to the requirement of switch device withstand voltage ability while the object of the invention is the application scenario for meeting some high voltage gain.

Embodiment two: composition graphs 5 to Fig. 9 illustrates present embodiment, present embodiment is the checking to the switch couples inductive type dual bootstrap three level zeta converter described in execution mode one.

(1) in software Matlab software, simulation analysis is carried out to foregoing circuit topology.In artificial circuit, select main switch S ₁with main switch S ₂operating frequency be 50kHz, conduction phase angle differs 180 °, auxiliary switch S ₀with two main switch S ₁with main switch S ₂complementary conducting.Selecting circuit input voltage is 10V, and duty ratio in regulating circuit and load resistance, make the output voltage of circuit be 50V.Wherein, the former end of the coupling inductance obtained in Matlab software and current waveform, the electric capacity C of secondary end ₅the voltage waveform at two ends and output voltage waveforms are respectively as shown in Fig. 5, Fig. 6 and Fig. 7.

(2) build experiment porch according to Fig. 1, record actual waveform figure as shown in Figure 8 and Figure 9 according to this experiment porch.As can be seen from the figure, experimental data is identical with emulated data several.

Claims (1)

1. switch couples inductive type dual bootstrap three level zeta converter, is characterized in that: it comprises electric capacity C ₀, electric capacity C ₁, electric capacity C ₂, electric capacity C ₃, electric capacity C ₄, electric capacity C ₅, electric capacity C ₆, diode D ₁, diode D ₂, diode D ₃, diode D ₄, diode D ₅, diode D ₆, diode D ₇, diode D ₈, diode D ₉, diode D ₁₀, inductance L ₀, coupling inductance L ₁, coupling inductance L ₂, resistance R ₀, main switch S ₁, main switch S ₂with auxiliary switch S ₀, described main switch S ₁, main switch S ₂with auxiliary switch S ₀metal-oxide-semiconductor is all adopted to realize;

Electric capacity C ₁with electric capacity C ₂series connection, forms series arm, and one end of this series arm connects main switch S ₁positive pole, the other end of series arm connects main switch S ₂negative pole, the two ends of the first series arm are as the input of described converter;

Form coupling inductance L ₁two inductance reversal connections, coupling inductance L ₁same Name of Ends connect diode D respectively ₇two ends, diode D ₇anode also connect main switch S simultaneously ₁negative pole, coupling inductance L ₁another terminals of former end connect diode D ₈anode, coupling inductance L ₁another terminals of secondary end connect diode D ₁anode, diode D ₁negative electrode connect main switch S ₂positive pole;

Diode D ₈negative electrode connect electric capacity C ₃one end, electric capacity C ₃the other end connect diode D simultaneously ₃negative electrode and auxiliary switch S ₀positive pole, diode D ₃anode connect main switch S ₁negative pole;

Auxiliary switch S ₀negative pole connect electric capacity C simultaneously ₄one end and diode D ₄anode, C ₄the other end connect diode D ₉anode, diode D ₄negative electrode connect main switch S ₂positive pole;

Form coupling inductance L ₂two inductance reversal connections, coupling inductance L ₂same Name of Ends connect diode D respectively ₉two ends, diode D ₉anode also connect diode D simultaneously ₂negative electrode, diode D ₂anode connect main switch S ₁negative pole, coupling inductance L ₂another terminals of former end connect diode D ₁₀anode, coupling inductance L ₂another terminals of secondary end connect diode D ₁₀anode, diode D ₁₀negative electrode also connect main switch S simultaneously ₂positive pole;

Diode D ₂anode also connect electric capacity C simultaneously ₅one end, diode D ₁₀negative electrode also connect electric capacity C simultaneously ₆one end, electric capacity C ₅the other end connect diode D simultaneously ₅negative electrode and inductance L ₀one end, diode D ₅anode connect diode D ₆negative electrode, diode D ₆anode connect electric capacity C simultaneously ₆the other end and electric capacity C ₀one end, electric capacity C ₀the other end connect inductance L ₀the other end, electric capacity C ₀two ends as the output of described converter;

Diode D ₅with diode D ₆common port connect electric capacity C ₁with electric capacity C ₂common port.