CN103840694A - Topological structure of switch inductance inverted-L-shaped Z-source inverter - Google Patents

Abstract

Provided is a topological structure of a switch inductance inverted-L-shaped Z-source inverter. The topological structure comprises a direct-current power supply and an inverter bridge and is characterized in that an inverted-L-shaped Z-source network with a switch inductance unit is additionally arranged between the direct-current power supply and the inverter bridge, namely the front end of the inverter bridge is connected with the inverted-L-shaped Z-source network with the switch inductance unit. The topological structure has the advantages that capacitor voltage stress in the Z-source network always maintains twice the voltage of the direct-current power supply in the process that voltage of the inverter is amplified; the situation that capacitor voltage stress of a traditional Z-source inverter increases with a through duty ratio is avoided; compared with the traditional Z-source inverter and the switch inductance Z-source inverter, the inverter reduces inductance current stress on the condition of identical voltage gains; voltage gain obtained when the through duty ratio is small is improved; influences of impact currents on the inverter bridge can be avoided when the system is started.

Description

Switched inductors Γ type Z-source inverter topological structure

Technical field

The present invention relates to a kind of switched inductors Γ type Z-source inverter topological structure.

Background technology

The topological structure of existing Z-source inverter has multiple, as: traditional Z source inventer as shown in Figure 2, accurate Z-source inverter as shown in Figure 3, switched inductors Z-source inverter and accurate switched inductors Z-source inverter as shown in Figure 5 etc. as shown in Figure 4.Can find out from Fig. 2～5, in above various Z-source inverters, except having inductance, all contain two capacity cells, and the voltage stress of electric capacity increases along with the increase of straight-through duty ratio.Because capacitance voltage stress range is larger, this will reduce the useful life of electric capacity, and has limited the size of straight-through duty ratio; While startup, may there is impulse current in system; In addition, in above Z-source inverter, inductive current stress is larger.

Summary of the invention

For above problem, the object of this invention is to provide a kind of topological structure of switched inductors Γ type Z-source inverter, in the Z source network of this inverter, only contain a capacity cell, and to make capacitance voltage stress be certain value, and reduced inductive current stress under identical voltage gain condition.

For achieving the above object, the technical solution used in the present invention is: a kind of switched inductors Γ type Z-source inverter topological structure, this topological structure includes DC power supply, inverter bridge, it is characterized in that: between described DC power supply and inverter bridge, add a Γ type Z source network that contains switched inductors unit, connect at the front end of inverter bridge the Γ type Z source network that contains switched inductors unit.

The described Γ type Z source network that contains switched inductors unit comprises three inductance, an electric capacity and four diodes; If three inductance are respectively 1# inductance L ₁, 2# inductance L ₂with 3# inductance L ₃; Four diodes are respectively 1# diode D ₁, 2# diode D ₂, 3# diode D ₃with 4# diode D ₄; An electric capacity is 1# capacitor C;

Described 1# diode D ₁anode be connected with the positive pole of DC power supply Vdc, D ₁negative electrode respectively with 1# inductance L ₁one end, 2# inductance L ₂one end and 2# diode D ₂anode be connected; 1# inductance L ₁the other end be connected with the positive pole of capacitor C, the negative pole of capacitor C is connected with the negative pole of DC power supply Vdc and the lower brachium pontis of inverter bridge; 2# inductance L ₂the other end and 3# diode D ₃with 4# diode D ₄anode be connected; 3# inductance L ₃one end and 2# diode D ₂negative electrode and 3# diode D ₃negative electrode be connected, 3# inductance L ₃the other end and 4# diode D ₄negative electrode and the upper brachium pontis of inverter bridge be connected.

Described L ₁=L ₂=L ₃=L, L is the inductance value of inductance element in the Γ type Z source network that contains switched inductors unit.

The present invention has following advantage and technique effect:

1. by containing two electric capacity in traditional Z source network, be kept to and only contain an electric capacity, and capacitance voltage stress is certain value in the process of boosting, can extend useful life, the reduction system volume of system and reduce system cost.

2. under identical voltage gain, capacitance voltage stress is certain value, has reduced capacitance voltage stress compared with other type Z-source inverter.

3. because switched inductors unit is at the front end of inverter bridge, so the impulse current to inverter bridge when this inverter can avoid system to start.

4. under the condition of identical voltage gain, the inductive current gain of switched inductors Γ type Z-source inverter is less than traditional Z source inventer and switched inductors Z-source inverter.

Brief description of the drawings:

Fig. 1 is inductive type Z-source inverter topological structure of the present invention;

Fig. 2 is traditional Z source inventer;

Fig. 3 Z-source inverter that is as the criterion;

Fig. 4 is switched inductors Z-source inverter;

Fig. 5 is the accurate Z-source inverter of switched inductors;

Fig. 6 be the present invention in the time of pass-through state, switched inductors Γ type Z-source inverter topological structure;

Fig. 7 be the present invention in the time of non-pass-through state, switched inductors Γ type Z inverter topology;

Fig. 8 is traditional Z source inventer, switched inductors Z-source inverter and switched inductors Γ type Z-source inverter voltage gain correlation curve;

Fig. 9 is traditional Z source inventer, switched inductors Z-source inverter and switched inductors Γ type Z-source inverter capacitance voltage stress correlation curve;

Figure 10 is traditional Z source inventer and switched inductors Γ type Z-source inverter inductive current stress correlation curve;

Figure 11 is switched inductors Z-source inverter and switched inductors Γ type Z-source inverter inductive current stress correlation curve.

Embodiment

By reference to the accompanying drawings inductive type Z-source inverter topological structure of the present invention is illustrated.

In the switched inductors Γ type Z source network of inverter of the present invention, only contain a capacity cell; In the process of boosting, capacitance voltage stress is certain value; Inductive current stress under identical voltage gain condition is less.

As shown in Figure 1: a kind of switched inductors Γ type Z-source inverter topological structure, this topological structure includes DC power supply, inverter bridge.Between described DC power supply and inverter bridge, add a Γ type Z source network that contains switched inductors unit, connect at the front end of inverter bridge the Γ type Z source network that contains switched inductors unit.The described Γ type Z source network that contains switched inductors unit comprises three inductance, an electric capacity and four diodes; Wherein, three inductance are respectively 1# inductance L ₁, 2# inductance L ₂with 3# inductance L ₃; Four diodes are respectively 1# diode D ₁, 2# diode D ₂, 3# diode D ₃with 4# diode D ₄; An electric capacity is 1# capacitor C;

Described 1# diode D ₁anode be connected with the positive pole of DC power supply Vdc, D ₁negative electrode respectively with 1# inductance L ₁one end, 2# inductance L ₂one end and 2# diode D ₂anode be connected; 1# inductance L ₁the other end be connected with the positive pole of capacitor C, the negative pole of capacitor C is connected with the negative pole of DC power supply Vdc and the lower brachium pontis of inverter bridge; 2# inductance L ₂the other end and 3# diode D ₃with 4# diode D ₄anode be connected; 3# inductance L ₃one end and 2# diode D ₂negative electrode and 3# diode D ₃negative electrode be connected, 3# inductance L ₃the other end and 4# diode D ₄negative electrode and the upper brachium pontis of inverter bridge be connected.

Described L ₁=L ₂=L ₃=L, L is the inductance value of inductance element in the Γ type Z source network that contains switched inductors unit.

As shown in Figure 6: in the time working in pass-through state, 1#, 2# and 4# diode D in Γ type Z source network ₁, D ₂and D ₄conducting, 3# diode D ₃cut-off, wherein 2# and 3# inductance L ₂and L ₃be and be connected in parallel, now inductance stored energy;

As shown in Figure 7: in the time working in non-pass-through state, 1#, 2# and 4# diode D in Γ type Z source network ₁, D ₂and D ₄cut-off, 3# diode D ₃conducting, wherein 2# and 3# inductance L ₂and L ₃be and be connected in series, now inductance releases energy to load, and the voltage gain of this Z-source inverter is:

$B=\frac{2+D}{1-D}$

Wherein: B is voltage gain; D is straight-through duty ratio.

In this Z-source inverter, average inductor current is:

$L_L=\frac{L_{l}D+L(2+D)}{{\mathrm{LR}}_l}{V}_{\mathrm{dc}}$

Wherein: L is the inductance value of inductance element in Z source network; L _lfor load inductance; R _lfor load resistance; V _dcfor DC power supply voltage.

Load average electric current is:

$I_l=(2+D)\frac{V_{\mathrm{dc}}}{R_l}$

When load is pure when resistive, inductive current stress is:

$I_L=\frac{2+D}{1-D}\frac{V_{\mathrm{dc}}}{R_l}$

The voltage gain correlation curve of switched inductors Γ type Z-source inverter, traditional Z source inventer and switched inductors Z-source inverter as shown in Figure 8, known in figure, in the time of little straight-through duty ratio, the voltage gain of switched inductors Γ type Z-source inverter is larger.

The capacitance voltage stress correlation curve of switched inductors Γ type Z-source inverter, traditional Z source inventer and switched inductors Z-source inverter as shown in Figure 9.Visible, the capacitance voltage stress of switched inductors Γ type Z-source inverter does not change with the variation of straight-through duty ratio, and the capacitance voltage stress range of other two kinds of Z-source inverters is larger.Wherein: SL-ZSI is switched inductors type Z-source inverter; Trad.ZSI is traditional Z source inventer.

Inductive current stress correlation curve in switched inductors Γ type Z-source inverter as shown in figure 10 and traditional Z source inventer, inductive current stress correlation curve in the switched inductors Γ type Z-source inverter shown in Figure 11 and switched inductors Z-source inverter and traditional Z source inventer.

Can find out from Fig. 8,10 and 11, in switched inductors Γ type Z-source inverter, inductive current STRESS VARIATION is less, and under identical voltage gain condition, its inductive current stress is less than the inductive current stress in traditional Z source inventer and switched inductors Z-source inverter.

Claims (3)

1. a switched inductors Γ type Z-source inverter topological structure, this topological structure includes DC power supply, inverter bridge, it is characterized in that: between described DC power supply and inverter bridge, add a Γ type Z source network that contains switched inductors unit, connect at the front end of inverter bridge the Γ type Z source network that contains switched inductors unit.

2. switched inductors Γ type Z-source inverter topological structure according to claim 1, is characterized in that: described in contain switched inductors unit Γ type Z source network comprise three inductance, an electric capacity and four diodes; If three inductance are respectively 1# inductance L ₁, 2# inductance L ₂with 3# inductance L ₃; Four diodes are respectively 1# diode D ₁, 2# diode D ₂, 3# diode D ₃with 4# diode D ₄; An electric capacity is 1# capacitor C;

Described 1# diode D ₁anode be connected with the positive pole of DC power supply Vdc, D ₁negative electrode respectively with 1# inductance L ₁one end, 2# inductance L ₂one end and 2# diode D ₂anode be connected; 1# inductance L ₁the other end be connected with the positive pole of capacitor C, the negative pole of capacitor C is connected with the negative pole of DC power supply Vdc and the lower brachium pontis of inverter bridge; 2# inductance L ₂the other end and 3# diode D ₃with 4# diode D ₄anode be connected; 3# inductance L ₃one end and 2# diode D ₂negative electrode and 3# diode D ₃negative electrode be connected, 3# inductance L ₃the other end and 4# diode D ₄negative electrode and the upper brachium pontis of inverter bridge be connected.

3. switched inductors Γ type Z-source inverter topological structure according to claim 2, is characterized in that: described L ₁=L ₂=L ₃=L, L is the inductance value of inductance element in the Γ type Z source network that contains switched inductors unit.

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