CN203352432U - Topological structure of induction type Z-source inverter - Google Patents

Abstract

The utility model provides a topological structure of an inductive Z-source inverter, which includes a DC power supply and an inverter bridge, and a network composed of only inductors and diodes between the DC power supply and the inverter bridge; the network is equipped with n(n≥2) inductors, there should be 3×(n-1) diodes to match, and form an inductor and diode network, n inductors in the network form n-1 circuit units, each unit Contains two inductors and three diodes. The effect of the utility model is that the capacitive element is removed as a necessary component in the Z-source network of the Z-source inverter, which can prolong the service life of the system, reduce the system volume and reduce the system cost. The inductive Z-source inverter avoids the resonance phenomenon caused by the coexistence of capacitance and inductance, and avoids the inrush current that exists when the Z-source inverter starts. Under the condition of the same voltage gain, the inductor current stress of the inductive Z-source inverter is smaller than that of the traditional Z-source inverter and switched inductor Z-source inverter.

Description

Inductive Z-source Inverter Topology

technical field

The utility model relates to a topological structure of an inductance type Z source inverter.

Background technique

There are many topologies of existing Z-source inverters, such as: the traditional Z-source inverter shown in Figure 2, the quasi-Z-source inverter shown in Figure 3, and the switch inverter shown in Figure 4. The inductance Z source inverter and the quasi-switching inductance Z source inverter shown in Figure 5, etc. It can be seen from Figures 2 to 5 that all of the above Z-source inverters contain capacitive components in addition to inductance. Due to the existence of capacitive components, it is inevitable that the life of the system is short, there may be resonance between the inductor and the capacitor, and there may be inrush current when the system starts; in addition, the inductor current stress in the above Z-source inverter is relatively large, and The voltage gain can only be changed by changing the direct duty cycle.

Contents of the invention

In response to the above problems, the purpose of this utility model is to provide a topological structure of an inductive Z-source inverter. The Z-source network of the inverter only contains inductive elements, which eliminates the previous topology that must contain capacitive elements in the Z-source network. Structure; the voltage gain can be adjusted by adjusting the number of inductive elements and the direct duty cycle; the inductor current stress is small under the same voltage gain condition.

In order to achieve the above purpose, the technical solution adopted by the utility model is to provide a topological structure of an inductive Z-source inverter. The topological structure of an inductive Z-source inverter includes a DC power supply and an inverter bridge. There is only a network composed of inductors and diodes between the DC power supply and the inverter bridge; if there are n (n≥2) inductors in the network, there should be 3×(n-1) diodes to match, and the formed Inductor and diode network, n inductors in the network form n-1 circuit units, each unit contains two inductors and three diodes; n inductors form n-1 units; the two inductors are 1# Inductance and 2# inductance; the three diodes are 1# diode, 2# diode and 3# diode; for two adjacent units, the 2# inductance of the previous unit is the 1# inductance of the latter unit;

One end of the 1# inductance of any unit in the network is connected to the anode of the 1# diode, the other end of the 1# inductance is connected to the anodes of the 2# and 3# diodes; one end of the 2# inductance is connected to the 1# and 2# diodes The cathode of the 2# inductor is connected to the cathode of the 3# diode;

When working in the straight-through state, in any unit in the network, 1# and 3# diodes are turned on, 2# diodes are turned off, and the 1# and 2# inductors in each unit are connected in parallel, and the inductors store energy at this time; when When working in the non-through state, any unit in the network, 1# and 3# diodes are cut off, 2# diodes are turned on, and the 1# and 2# inductances in each unit are connected in series, and the inductance releases energy to the load at this time .

The utility model has the following effects:

1. The capacitive element is removed as a necessary part of the Z-source network in the Z-source inverter, which can prolong the service life of the system, reduce the system volume and reduce the system cost.

2. Due to the removal of capacitive components, the inductive Z-source inverter avoids the resonance phenomenon caused by the coexistence of capacitance and inductance.

3. Due to the removal of capacitive components, the inductive Z-source inverter avoids the inrush current that exists when the Z-source inverter starts.

4. Under the condition of the same voltage gain, the inductive current stress of the inductive Z-source inverter is smaller than that of the traditional Z-source inverter and the switched inductance Z-source inverter.

Description of drawings

Fig. 1 is the topology structure of the inductance type Z source inverter of the present utility model;

Figure 2 is a traditional Z-source inverter;

Figure 3 is a quasi-Z source inverter;

Figure 4 is a switched inductor Z source inverter;

Figure 5 is a switched inductance quasi-Z source inverter;

Fig. 6 is the topology structure of the inductive Z-source inverter in the straight-through state of the present utility model;

Fig. 7 is the topological structure of the inductive Z inverter in the non-straight-through state of the present invention;

Figure 8 is the voltage gain curve of the inductive Z-source inverter for different n values of the present invention;

Fig. 9 is the comparison curve of the voltage gain of the inductive type Z source inverter when different types of Z source inverters of the present invention and n take different values;

Fig. 10 is the comparison curve of inductance current stress in the inductance type Z source inverter of the present invention and the switching inductance Z source inverter;

Fig. 11 is a comparison curve of inductor current stress between the inductive Z-source inverter of the present invention and the traditional Z-source inverter.

Detailed ways

The topology structure of the inductive Z-source inverter of the present invention is described in conjunction with the accompanying drawings.

The Z source network of the inverter of the present invention only contains inductive elements, which removes the topology structure that must contain capacitive elements in the previous Z source network; the voltage gain can be adjusted by adjusting the number of inductive elements and the direct duty cycle ; The inductor current stress is smaller under the same voltage gain condition.

The topology structure of the inductance type Z source inverter of the utility model includes a DC power supply and an inverter bridge, and only includes a network composed of an inductor and a diode between the DC power supply and the inverter bridge; in the network If there are n (n ≥ 2) inductors, there should be 3×(n-1) diodes to match and form an inductor and diode network. The n inductors in the network form n-1 circuit units, each A unit contains two inductors and three diodes; n inductors make up n-1 units; the two inductors are 1# inductor and 2# inductor; the three diodes are 1# diode, 2# diode and 3# Diode; for two adjacent units, the 2# inductance of the previous unit is the 1# inductance of the latter unit;

One end of the 1# inductance of any unit in the network is connected to the anode of the 1# diode, the other end of the 1# inductance is connected to the anodes of the 2# and 3# diodes; one end of the 2# inductance is connected to the 1# and 2# diodes The cathode of the 2# inductor is connected to the cathode of the 3# diode;

When working in the straight-through state, in any unit in the network, 1# and 3# diodes are turned on, 2# diodes are turned off, and the 1# and 2# inductances in each unit are connected in parallel, and the inductance stores energy at this time;

When working in the non-through state, any unit in the network, 1# and 3# diodes are cut off, 2# diodes are turned on, and the 1# and 2# inductances in each unit are connected in series, and the inductance is released to the load at this time energy.

The DC power supply (Vdc) is connected between the inductor and diode network and the lower bridge arm of the inverter bridge, or between the inductor and diode network and the upper bridge arm of the inverter bridge.

As shown in FIG. 1 , where: L ₁ =L ₂ =L ₃ =...=L _n-1 =L _n =L, n is the number of inductors. The structure of the inductive Z-source inverter is composed of a Z-source network composed of inductors and diodes and an inverter bridge. The Z source network composed of inductors and diodes is composed of n inductors and 3×(n-1) diodes. One end of _L1 is connected to the anode of _D1,1 , and the other end of _L1 is connected to the anodes of _D1,2 and _D1,3 . One end of L ₂ is connected to the cathodes of D _1,1 and D _1,2 , and to the anode of D _2,1 ; the other end of L ₂ is connected to the anodes of D _2,2 and D _2,3 . By analogy, it can be seen that one end of L _n-1 is connected to the cathode of D _n-2,1 and D _n-2,2 , and is connected to the anode of D _n-1,1 ; the other end of L ₂ is connected to the anode of D _{n-1 ,2} is connected to the anode of D _n-1,3 . One end of L _n is connected to the cathodes of D _n-1,1 and D _n-1,2 , and the other end of L _n is connected to D _n-1,3 . In addition, the DC power supply Vdc can be placed between the inductor and diode network and the lower bridge arm of the inverter bridge, or between the inductor and diode network and the upper bridge arm of the inverter bridge. The inductance and diode network in the straight-through state are equivalent to each inductance being connected in parallel, and the inductance stores energy at this time.

When working in the non-through state, the equivalent circuit is shown in Figure 7. The inductance and diode network in the through state are equivalent to each inductor in series. At this time, the inductance releases energy to the load. The voltage gain of the Z-source inverter is:

$\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; D.</span>}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; D.</span>}}$

Among them: n is the number of inductors in the Z source network; D is the direct duty cycle.

The average inductor current in this Z-source inverter is:

${\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="I"\; filenames="HDA00003464845000033.png,HDA00003464845000034.png"\; state="\{\{state\}\}">I</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; D.</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; nL</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; D.</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; D.</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; dc</span>}}$

Among them: L is the inductance of the inductance element in the Z source network; L _L is the load inductance; R _L is the load resistance; V _dc is the DC power supply voltage.

And the inductor currents in the inductor network are equal. In this Z-source inverter, the average load current is:

${\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="I"\; filenames="HDA00003464845000033.png,HDA00003464845000034.png"\; state="\{\{state\}\}">I</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; D.</span>}<span\; class="notranslate">\; )</span>}{{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}\mathrm{<span\; class="notranslate">\; D.</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; nL</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; D.</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; dc</span>}}$

When the load is purely resistive, the inductor current stress and load average current are:

${\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; D.</span>}}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; D.</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; dc</span>}}$ ${\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; D.</span>}}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; dc</span>}}$

Figure 8 shows the voltage gain curve of the inductive Z-source inverter when n takes different values. It can be seen from the figure that the inverter can be adjusted in two ways by adjusting the number of inductors in the Z-source network and the direct duty cycle. Adjust the voltage gain of the inverter; compared with other types of Z-source inverters, the inverter has more diverse ways to adjust the voltage gain.

Figure 9 shows the voltage gain comparison curves of different types of Z-source inverters and inductive Z-source inverters when n takes different values. It can be seen from the figure that the inductive Z-source inverter can adjust the voltage gain by adjusting the amount of inductance, which can make the gain better than other types of Z-source inverters in a certain range, and is suitable for when the through-duty ratio varies. In addition, the voltage gain of the inductive Z-source inverter changes more smoothly than other types of Z-source inverters, which makes it more convenient to control. Among them: SL-ZSI is a switched inductance Z-source inverter; trad.ZSI is a traditional Z-source inverter.

Fig. 9 Comparison curves of voltage gain between inductive Z-source inverter and other Z-source inverters for different n values; Fig. 11 Comparison curve of inductor current stress in inductive Z-source inverter and traditional Z-source inverter.

It can be seen from Figures 10 and 11 that the inductor current stress in the inductive Z-source inverter changes little. When n=1, 2, 3, 4, 5, 6, and D∈[0,0.3], the inductor current The stress varies from 1 to 3.6; while the current stress of the traditional Z inverter and the switched inductance Z source inverter both range from (1 to +∞). And at the same voltage gain, the current stress of L-ZSI is lower than that of traditional ZSI and SL-ZSI.

Table 1 and Table 2 show the comparison of inductor current stress in inductive Z-source inverter, traditional Z-source inverter and switched inductor Z-source inverter under the same voltage gain condition (the load is purely resistive) .

Table 1 Comparison of inductor current stress in inductive Z-source inverter and switched inductance Z-source inverter

Table 2 Comparison of inductor current stress between inductive Z-source inverter and traditional Z-source inverter

Claims (2)

1. A kind of inductance type Z source inverter topological structure, this topological structure comprises DC power supply, inverter bridge, is characterized in that: only contain the network that inductance and diode form between described DC power supply and inverter bridge; If there are n (n ≥ 2) inductors in the network, there should be 3×(n-1) diodes to match, and the formed inductor and diode network, n inductors in the network form n-1 Circuit unit, each unit contains two inductors and three diodes; n inductors make up n-1 units; the two inductors are respectively 1# inductor and 2# inductor; the three diodes are respectively 1# diode and 2# Diode and 3# diode; for two adjacent units, the 2# inductance of the previous unit is the 1# inductance of the latter unit; One end of the 1# inductance of any unit in the network is connected to the anode of the 1# diode, the other end of the 1# inductance is connected to the anodes of the 2# diode and the 3# diode; one end of the 2# inductance is connected to the 1# diode and the 2# diode #The cathode of the diode is connected, and the other end of the 2# inductor is connected to the cathode of the 3# diode; When working in the straight-through state, any unit in the network, the 1# diode and the 3# diode are turned on, and the 2# diode is turned off, and the 1# inductor and the 2# inductor in each unit are connected in parallel, and the inductor stores energy at this time ; When working in the non-straight-through state, any unit in the network, 1# diode and 3# diode are cut off, 2# diode is turned on, and the 1# inductance and 2# inductance in each unit are connected in series. The load releases energy. 2. The inductive Z-source inverter topology according to claim 1, characterized in that: the DC power supply (Vdc) is connected between the inductor and diode network and the lower bridge arm of the inverter bridge, or connected between Between the inductor and diode network and the upper arm of the inverter bridge.

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