CN102780388A - Direct current bus and capacitor mixed circuit and power inverter - Google Patents

Abstract

The invention discloses a direct current bus and capacitor mixed circuit, which comprises a parallel circuit and a power switch; the parallel circuit is connected with an direct current end of the power switch; the parallel circuit comprises a first type capacitor and a second type capacitor; and the first type capacitor and the second type capacitor are in parallel. The embodiment provided by the invention also provides a corresponding power inverter. According to the technical scheme provided by the invention, the two types of capacitors are used in parallel, so that the reliability and the service life of the circuit can be improved.

Description

A kind of dc-link capacitance is used circuit and power inverter with

Technical field

The present invention relates to the circuit engineering field, be specifically related to a kind of dc-link capacitance and use circuit and power inverter with.

Background technology

Power inverter dc bus major function comprises keeps that DC bus-bar voltage is stable, energy supports and several aspects such as High frequency filter.Traditional power inverter dc-link capacitance configuration is generally only selected one type electric capacity for use, perhaps all adopts electrochemical capacitor or all adopts thin-film capacitor.

Electrochemical capacitor unit volume appearance value is big; But it is because endophyte resistance is bigger, a little less than the anti-ripple current ability, and the high order harmonic component composition in the electric current that ripple current is meant; Can on electric capacity, dissipate; If the ripple composition of electric current is excessive, surpassed the maximum allowable ripple current of electric capacity, can cause electric capacity to burn.Simultaneously, the heating that causes more greatly of electrochemical capacitor dead resistance can cause electrolyte to be waved gradually and shorten life-span of electrochemical capacitor.And thin-film capacitor is just in time opposite, and the ability of its anti-ripple current is 4-5 a times of electrochemical capacitor, but its unit volume appearance value has only electrochemical capacitor 1/6 to 1/7.According to traditional dc-link capacitance collocation method; If select electrochemical capacitor merely for use, consider that the ripple current ability needs a greater number electrochemical capacitor, if select thin-film capacitor merely for use; Consider the stable and energy support of DC bus-bar voltage; Need a greater number thin-film capacitor again, it is big finally to cause taking up room, and overall cost is higher.

Summary of the invention

The embodiment of the invention provides a kind of dc-link capacitance to use circuit with, can improve the reliability and the life-span of circuit.The embodiment of the invention also provides corresponding power inverter.

First aspect present invention provides a kind of dc-link capacitance to use circuit with; Comprise parallel circuits and power switch; Said parallel circuits is connected with the dc terminal of said power switch; Said parallel circuits comprises the first kind electric capacity and the second type electric capacity, and said first kind electric capacity is parallelly connected with the said second type electric capacity.

In conjunction with first aspect, in first kind of possible implementation, said parallel circuits also comprises the inductance that is used to regulate electric current, and said inductance and the said first kind capacitances in series that is used to regulate electric current to keep the stable of DC bus-bar voltage, reduces ripple voltage.

In conjunction with first aspect or first kind of possible implementation of first aspect, in second kind of possible implementation, the said second type electric capacity is connected the side near said power switch.

In conjunction with first aspect or first kind of possible implementation of first aspect, in the third possible implementation, said parallel circuits has a plurality of, and each parallel circuits series connection, and each parallel circuits is connected with the dc terminal of said power switch.

In conjunction with first aspect or first kind of possible implementation of first aspect, in the 4th kind of possible implementation, said first kind electric capacity is electrochemical capacitor, and the said second type electric capacity is thin-film capacitor.

Second aspect present invention provides a kind of power inverter, comprises that dc-link capacitance uses circuit and battery component with, and said dc-link capacitance is used circuit with and is connected with said battery component, and the electric energy that said battery component provides is done direct current or exchanged conversion;

Said dc-link capacitance is used circuit with and is comprised parallel circuits and power switch; Said parallel circuits is connected with the dc terminal of said power switch; Said parallel circuits comprises the first kind electric capacity and the second type electric capacity, and said first kind electric capacity is parallelly connected with the said second type electric capacity.

The embodiment of the invention provides a kind of dc-link capacitance to use circuit with; Comprise parallel circuits and power switch; Said parallel circuits is connected with the dc terminal of said power switch; Said parallel circuits comprises first kind electric capacity, the second type electric capacity, and said first kind electric capacity is parallelly connected with the said second type electric capacity.Only use one type electric capacity to compare with power conversion circuit of the prior art, the power conversion circuit that the embodiment of the invention provides uses reliability and the life-span that can improve circuit with two types electric capacity parallel connection.

Description of drawings

Fig. 1 is that the direct current bus capacitor that the embodiment of the invention provides is used circuit diagram with;

Another dc-link capacitance that Fig. 2 embodiment of the invention provides is used circuit diagram with;

Fig. 3 is that another dc-link capacitance that the embodiment of the invention provides is used circuit diagram with.

Embodiment

The embodiment of the invention provides a kind of dc-link capacitance to use circuit with, can improve the reliability and the life-span of circuit.The embodiment of the invention also provides corresponding power inverter.Below be elaborated respectively.

Consult Fig. 1; The dc-link capacitance that the embodiment of the invention provides is used circuit with and is comprised parallel circuits 10 and power switch 20; The dc terminal of parallel circuits 10 power switchs 20 connects; Parallel circuits 10 comprises the first kind electric capacity 101 and the second type electric capacity 102, and first kind electric capacity 101 is parallelly connected with the second type electric capacity 102.

Wherein, first kind electric capacity 101 can be electrochemical capacitor, and the second type electric capacity 102 can be thin-film capacitor.

First kind electric capacity 101 equivalent parameterss comprise first capacitor C 1, the first equivalent series resistance ESR1, the first equivalent series inductance ES L1, and first capacitor C 1 is connected with the first equivalent series resistance ESR1 and the first equivalent series inductance ESL1.

The second type electric capacity equivalent parameters comprises second capacitor C 2, the second equivalent series resistance ESR2, the second equivalent series inductance ESL2, and second capacitor C 2 is connected with the second equivalent series resistance ESR2 and the second equivalent series inductance ESL2.

Among Fig. 1 and Fig. 2, ESR1 is an electrochemical capacitor equivalence dead resistance, and ERL1 is an electrochemical capacitor equivalence stray inductance; C1 is an electrochemical capacitor; ESR2 is a thin-film capacitor equivalence dead resistance, and ESL2 is a thin-film capacitor equivalence stray inductance, and C2 is a thin-film capacitor; I1 is the electrochemical capacitor branch current, and I2 is the thin-film capacitor branch current.

In the parallel circuits 10; Because of the anti-ripple ability of thin-film capacitor is strong, thus I2 can try one's best greatly, because of the anti-ripple ability of electrochemical capacitor; So it is littler that I1 is tried one's best; The relation of I1 and I2 and inductance can be set up through impedance, and establishing Z1 is the electrochemical capacitor branch impedance, and Z2 is the thin-film capacitor branch impedance;

$Z1=\sqrt{{\left(\mathrm{ESR}1\right)}^2+{[2\mathrm{\πf}\left(\mathrm{ESL}1\right)-\frac{1}{2\mathrm{\πfC}1}]}^2}$

$Z2=\sqrt{{\left(\mathrm{ESR}2\right)}^2+{[2\mathrm{\πf}\left(\mathrm{ESL}2\right)-\frac{1}{2\mathrm{\πfC}2}]}^2}$

Because of the circuit of every branch road than the inverse ratio that equals impedance, so arranged

In the embodiment of the invention, the ratio of electric current that can be is as required selected different thin-film capacitors and electrochemical capacitor for use.

In fact, there be not under the situation of outer coilloading stray inductance and cable or printed circuit board (PCB) (PCB, the stray inductance that PrintedCircuitBoard) wiring grade causes that on behalf of first kind electric capacity, ESL1 can produce.

In the embodiment of the invention; Dc-link capacitance is used circuit with; Comprise parallel circuits and power switch; Said parallel circuits is connected with the dc terminal of said power switch, and said parallel circuits comprises first kind electric capacity, the second type electric capacity, and said first kind electric capacity is parallelly connected with the said second type electric capacity.Only use one type electric capacity to compare with power conversion circuit of the prior art, the power conversion circuit that the embodiment of the invention provides uses reliability and the life-span that can improve circuit with two types electric capacity parallel connection.

On the basis of the corresponding embodiment of above-mentioned Fig. 1; Consult Fig. 2; The dc-link capacitance that the embodiment of the invention provides is used with in the parallel circuits of circuit and is also comprised the inductance L that is used to regulate electric current; Said inductance L that is used for regulating circuit and first kind capacitances in series 101, the second type electric capacity 102 are parallelly connected with first kind electric capacity 101 and inductance L.The second type electric capacity 102 is connected the side near power switch 20, and the high frequency ripple electric current that causes of power switch 20 switching processes can be absorbed by thin-film capacitor C2 like this.

First kind electric capacity 101 equivalent parameterss comprise first capacitor C 1, the first equivalent series resistance ESR1, the first equivalent series inductance ESL1, and first capacitor C 1 is connected with the first equivalent series resistance ESR1 and the first equivalent series inductance ESL1.

The second type electric capacity equivalent parameters comprises second capacitor C 2, the second equivalent series resistance ESR2, the second equivalent series inductance ESL2, and second capacitor C 2 is connected with the second equivalent series resistance ESR2 and the second equivalent series inductance ESL2.

Among Fig. 1 and Fig. 2, ESR1 is an electrochemical capacitor equivalence dead resistance, and ERL1 is an electrochemical capacitor equivalence stray inductance; C1 is an electrochemical capacitor, and ESR2 is a thin-film capacitor equivalence dead resistance, and ESL2 is a thin-film capacitor equivalence stray inductance; C2 is a thin-film capacitor; L is outer coilloading, and I1 is the electrochemical capacitor branch current, and I2 is the thin-film capacitor branch current.

Can reconcile electric current I 1 and I2 through reconciling inductance L in the parallel circuits 10; Because of the anti-ripple ability of thin-film capacitor is strong, thus I2 can try one's best greatly, because of the anti-ripple ability of electrochemical capacitor; So it is littler that I1 is tried one's best; The relation of I1 and I2 and inductance can be set up through impedance, and establishing Z1 is the electrochemical capacitor branch impedance, and Z2 is the thin-film capacitor branch impedance;

$Z1=\sqrt{{\left(\mathrm{ESR}1\right)}^2+{[2\mathrm{\πf}(\mathrm{ESL}1+L)-\frac{1}{2\mathrm{\πfC}1}]}^2}$

$Z2=\sqrt{{\left(\mathrm{ESR}2\right)}^2+{[2\mathrm{\πf}\left(\mathrm{ESL}2\right)-\frac{1}{2\mathrm{\πfC}2}]}^2}$

Because of the circuit of every branch road than the inverse ratio that equals impedance, so

arranged

Can find out that by above three formula will keep I2 bigger, I1 is less; Only need the value of conciliation L to accomplish, thereby can keep the stable of DC bus-bar voltage, reduce ripple voltage; When the equivalent inductance of circuit was enough reconciled I1 and I2, the value that adds inductance L can be 0.

The circuit that provides in the present embodiment is applicable to two level topological transformation devices; Only need thin-film capacitor parallelly connected with electrochemical capacitor; Be connected on the inductance L of electrochemical capacitor branch road through conciliation, can adjust the electric current that is fit to two branch roads, fully the advantage of use and thin-film capacitor and electrochemical capacitor; Avoid shortcoming separately, improved the reliability and the life-span of circuit.

Consult Fig. 3, Fig. 3 is the circuit diagram that is applicable to three level topological transformation devices, can find out by Fig. 3, and two parallel circuits 10 series connection, and each parallel circuits after the series connection is connected with the dc terminal of said power switch.The dead resistance and the stray inductance that do not have detailed draw thin-film capacitor C4 and electrochemical capacitor C3 among Fig. 3; In fact the equivalent parameters of the electrochemical capacitor C3 among Fig. 3 comprises first capacitor C 1, the first equivalent series resistance ESR1, the first equivalent series inductance ESL1 among Fig. 1 or Fig. 2, and first capacitor C 1 is connected with the first equivalent series resistance ESR1 and the first equivalent series inductance ESL1.The equivalent parameters of thin-film capacitor C4 comprises second capacitor C 2, the second equivalent series resistance ESR2, the second equivalent series inductance ESL2, and second capacitor C 2 is connected with the second equivalent series resistance ESR2 and the second equivalent series inductance ESL2.

Originally be that what to provide among the embodiment is the circuit diagram of three level topological transformation devices, when the present invention is applied in many level change in topology device, only need that many series connection are several both can like Fig. 1 or parallel circuits shown in Figure 2.

The embodiment of the invention also provides a kind of power inverter; The power inverter that the embodiment of the invention provides comprises like Fig. 1 ~ dc-link capacitance shown in Figure 3 uses circuit and battery component with; Said dc-link capacitance is used circuit with and is connected with said battery component, and the electric energy that said battery component provides is done direct current or exchanged conversion.

Technical scheme provided by the invention is applicable to the power inverter of various different application such as uninterrupted power supply (UPS, uninterrupted power supply), frequency converter, photovoltaic DC-to-AC converter, wind electric converter.

Embodiment among the present invention, the technology that adopts thin-film capacitor and electrochemical capacitor to use with is carried out the configuration of power inverter dc bus, is applicable to two level; Three level and many level topological transformation device; Utilize inductance to carry out the electric current reasonable distribution, given full play to the advantage of two kinds of electric capacity, avoided shortcoming separately; System cost be can effectively reduce and, lifetime of system and reliability improved the requirement in space.

More than the dc-link capacitance that the embodiment of the invention provided is used with circuit and power inverter has carried out detailed introduction; Used concrete example among this paper principle of the present invention and execution mode are set forth, the explanation of above embodiment just is used for helping to understand method of the present invention and core concept thereof; Simultaneously, for one of ordinary skill in the art, according to thought of the present invention, the part that on embodiment and range of application, all can change, in sum, this description should not be construed as limitation of the present invention.

Claims (6)

1. a dc-link capacitance is used circuit with; It is characterized in that; Comprise parallel circuits and power switch; Said parallel circuits is connected with the dc terminal of said power switch, and said parallel circuits comprises the first kind electric capacity and the second type electric capacity, and said first kind electric capacity is parallelly connected with the said second type electric capacity.

2. circuit according to claim 1 is characterized in that said parallel circuits also comprises the inductance that is used to regulate electric current, and said inductance and the said first kind capacitances in series that is used to regulate electric current to keep the stable of DC bus-bar voltage, reduces ripple voltage.

3. circuit according to claim 1 and 2 is characterized in that, the said second type electric capacity is connected the side near said power switch.

4. circuit according to claim 1 and 2 is characterized in that said parallel circuits has a plurality of, and each parallel circuits series connection, and each parallel circuits is connected with the dc terminal of said power switch.

5. circuit according to claim 1 and 2 is characterized in that, said first kind electric capacity is electrochemical capacitor, and the said second type electric capacity is thin-film capacitor.

6. a power inverter is characterized in that, comprises that dc-link capacitance uses circuit and battery component with, and said dc-link capacitance is used circuit with and is connected with said battery component, and the electric energy that said battery component provides is done direct current or exchanged conversion;

Said dc-link capacitance is used circuit with and is comprised parallel circuits and power switch; Said parallel circuits is connected with the dc terminal of said power switch; Said parallel circuits comprises the first kind electric capacity and the second type electric capacity, and said first kind electric capacity is parallelly connected with the said second type electric capacity.

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