CN205336115U - Adopt transformer and voltage lifting technology's accurate Z source converter - Google Patents

Abstract

The utility model provides a quasi-Z source converter adopting transformer and voltage lifting technology. The converter includes a DC input power supply, a transformer (<i>T</i>) with a turn ratio of 1:<i>n</i>, a first diode (<i>D</i> ₁ ), first capacitor (<i>C</i> ₁ ), second capacitor (<i>C</i> ₂ ), second diode (<i>D</i> ₂ ), second An inductor (<i>L</i> ₁ ), a second inductor (<i>L</i> ₂ ), a third capacitor (<i>C</i> ₃ ), a third diode ( <i>D</i> ₃ ), switch tube (<i>S</i>), fourth diode (<i>D</i> ₄ ), output capacitor (<i>C _out </i>) and load. Compared with flyback converters and voltage-lifting quasi-Z source converters, the utility model has higher voltage gain, and is suitable for occasions of non-isolated high-gain DC voltage conversion.

Description

A Quasi-Z Source Converter Using Transformer and Voltage Lifting Technology

technical field

The utility model relates to the field of DC/DC converters, in particular to a quasi-Z source converter using a transformer and voltage lifting technology.

Background technique

In recent years, due to the dwindling of fossil fuels, renewable energy power generation systems have developed rapidly. Fuel cells have attracted the attention of many researchers because of their high power generation efficiency, power density, and low noise. However, the output of the fuel cell is a low-voltage and high-current direct current, so it is often necessary to output a stable high-voltage direct current through a DC/DC converter. However, many step-up DC/DC converters are limited by the duty cycle, parasitic parameters and losses, and cannot achieve a large boost. For example, the flyback converter has a voltage gain of nD/(1-D), where n is the transformer Turn ratio, D is the duty cycle, but due to the influence of parasitic parameters, its gain is limited; another example is the voltage lift quasi-Z source converter, its voltage gain is 2/(1-3D), compared with the Z source converter There has been some improvement, but there is still room for improvement.

Utility model content

The purpose of the utility model is to overcome the deficiencies of the above-mentioned prior art, and propose a quasi-Z source converter using transformer and voltage lifting technology.

The circuit of the utility model specifically includes a DC input power supply V _in , a transformer with a turn ratio of 1:n, a first diode, a first capacitor, a second capacitor, a second diode, a first inductor, a second inductor, A third capacitor, a third diode, a switch tube, a fourth diode, an output capacitor and a load.

The specific connection mode of the circuit of the utility model is as follows: the positive pole of the DC input power source V _in is connected to the terminal with the same name on the primary side of the transformer. The opposite end of the primary side of the transformer is connected to the same end of the secondary side of the transformer and one end of the second capacitor. The opposite end of the secondary side of the transformer is connected to the anode of the first diode. The cathode of the first diode is connected with one end of the first capacitor, one end of the first inductor and the anode of the second diode. The cathode of the second diode is connected with one end of the third capacitor and one end of the second inductor. The other end of the third capacitor is connected to the other end of the first inductor and the anode of the third diode. The cathode of the third diode is connected with the other end of the second inductor, the other end of the second capacitor, the drain of the switch tube and the anode of the fourth diode. The cathode of the fourth diode is connected with one end of the output capacitor and one end of the load. The output capacitor is connected in parallel with the load. The negative pole of the DC input power supply _Vin is connected to the other end of the first capacitor, the source of the switch tube, the other end of the output capacitor and the other end of the load.

Compared with the prior art, the utility model circuit has the advantages that: compared with the traditional flyback converter (its output voltage is ) and a voltage-lift quasi-Z source converter (its output voltage is ) and other DC/DC converters, in the case of the same duty cycle and input voltage, have a higher output voltage, the output voltage is Under the same input voltage and output voltage conditions, the circuit of the utility model can raise the low-level voltage to a high-level voltage only with a small duty cycle, and the input and output common ground, continuous input current, etc., so the utility model The circuit has a very wide application prospect.

Description of drawings

Figure 1 is a structural diagram of a quasi-Z source converter using transformer and voltage boosting technology.

Figure 2 is a voltage and current waveform diagram of the main components of a switching cycle.

Figure 3a and Figure 3b are circuit modal diagrams in a switching cycle.

Fig. 4 is the waveform diagram of the gain V _out /V _in of the proposed circuit, the flyback converter and the switched inductance quasi-Z source converter as the duty ratio D changes.

detailed description

The utility model will be further described in detail below in conjunction with the embodiments and accompanying drawings, but the implementation of the utility model is not limited thereto. It should be noted that, if there are any processes or parameters that are not specifically described in detail below, those skilled in the art can understand or implement them with reference to the prior art.

The basic topological structure of the utility model and the reference directions of the voltage and current of each main component are shown in Fig. 1 . For the convenience of verification, the devices in the circuit structure are regarded as ideal devices. The drive signal v _GS of the switching tube S, the current i D1 of the first diode D ₁ , the current i _D2 of the second diode D ₂ , the current i _D3 of the third diode D ₃ , the current i _D 4 of the fourth diode D ₄ i _D4 , the current i L1 of the first inductor L ₁ , the current i _L2 of the second inductor L ₂ , the current i _Lm of the excitation inductance _{L m} of the transformer T, the voltage V _C1 of the first capacitor C ₁ , the voltage V _C2 of the second capacitor C ₂ , The waveform diagram of the voltage V _C3 of the third capacitor C ₃ is shown in FIG. 2 .

In the stage t ₀ ~ t ₁ , the modal diagram of the converter at this stage is shown in Figure 3a, the driving signal v _GS of the switch tube S changes from low level to high level, the switch tube S is turned on, and the second and second _The diode D2 and the third diode _D3 are turned on under the forward voltage, and the _first diode D1 and the _fourth diode D4 are turned off under the reverse voltage. The DC input power supply V _in and the second capacitor C ₂ charge the excitation inductance L _m of the transformer T through the switch tube S at the same time, and the first capacitor C ₁ charges the second inductance L ₂ through the second diode D ₂ and the switch tube S at the same time charging, the first capacitor C ₁ charges the first inductor L ₁ through the third diode D ₃ and the switch tube S at the same time, and the first capacitor C ₁ passes through the second diode D ₂ , the third diode D ₃ and the The switch tube S charges the _third capacitor C3 at the same time. In addition, the output capacitor C _out supplies power to the load.

In the stage t ₁ ~ t ₂ , the modal diagram of the converter at this stage is shown in Figure 3b, the driving signal v _GS of the switch tube S changes from high level to low level, the switch tube S is turned off, and the second two The diode D ₂ and the third diode D ₃ are turned off under reverse voltage, and the first diode D ₁ and fourth diode D ₄ are turned on under forward voltage. The DC input power supply V _in and the excitation inductance L _m of the transformer T simultaneously charge the first capacitor C ₁ through the first diode D ₁ , and the DC input power supply V _in and the excitation inductance L _m of the transformer T pass through the fourth diode D ₄ Simultaneously charge the second capacitor C ₂ , the output capacitor C _out and the load, the first inductor L ₁ , the second inductor L ₂ and the third capacitor C ₃ simultaneously charge the second capacitor C ₂ through the first diode D ₁ , the first inductor L ₁ , the second inductor L ₂ and the third capacitor C ₃ charge the first capacitor C ₁ , the output capacitor C _out and the load simultaneously through the fourth diode D ₄ . In addition, the DC input power supply V _in , the excitation inductance L _m of the transformer T, the first inductance L ₁ , the second inductance L ₂ and the third capacitor C ₃ pass through the first diode D ₁ and the fourth diode D ₄ simultaneously Charges the output capacitor C _out and the load.

The steady-state gain of the utility model circuit is derived as follows.

Since the inductance values of the first inductor L ₁ and the second inductor L ₂ are equal, the voltage and current of the first inductor L ₁ and the second inductor L ₂ are equal.

Since the average value of the voltages of the first inductance L ₁ and the excitation inductance L _m of the transformer T is zero within one switching cycle, the following relationship can be obtained.

$<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; f</span>}\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; \&lsqb;</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 2</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>}<span\; class="notranslate">\; \&rsqb;</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; f</span>}\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

V _C1 = V _C3 (3)

And when the switch tube S is turned off, the output voltage V _out satisfies the following relationship.

${\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; u</span>}\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

Simultaneously solving equations (1), (2), (3) and (4) can obtain the relationship between the output voltage V _out and the DC input voltage V _in .

${\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; u</span>}\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; D.</span>}}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

The steady-state gains of the traditional flyback converter and the voltage-lift quasi-Z source converter are nD/(1-D) and 2/(1-3D) respectively (D is the duty cycle, n is the transformer turns ratio), When the turn ratio n=1, the steady-state gain comparison diagram between the proposed circuit of the present invention and the flyback converter and the voltage-lift quasi-Z source converter is shown in Figure 4, as can be seen from Figure 4, when the input voltage is At 10V, the circuit proposed by the utility model can be raised to about 200V only with a duty ratio of 0.18, while the other two converters require a larger duty ratio.

Claims (1)

1. A quasi-Z source converter using a transformer and voltage boosting technology, characterized in that it includes a DC input power supply, a transformer ( T ) with a turn ratio of 1: n , a first diode ( D ₁ ), a first Capacitor ( C ₁ ), second capacitor ( C ₂ ), second diode ( D ₂ ), first inductance ( L ₁ ), second inductance ( L ₂ ), third capacitor ( C ₃ ), third Diode ( D ₃ ), switch tube ( S ), fourth diode ( D ₄ ), output capacitor ( C _out ) and load; The positive pole of the DC input power supply is connected to the same-named end of the primary side of the transformer ( T ); the different-named end of the primary side of the transformer ( T ) is connected to the same-named end of the secondary side of the transformer ( T ) and the second capacitor ( C ₂ ) One end is connected; the opposite end of the secondary side of the transformer ( T ) is connected to the anode of the first diode ( D ₁ ); the cathode of the first diode ( D ₁ ) is connected to the first capacitor ( C ₁ ) One end of the first inductor ( L ₁ ) is connected to the anode of the second diode ( D ₂ ); the cathode of the second diode ( D ₂ ) is connected to one end of the third capacitor ( C ₃ ) and One end of the second inductor ( L ₂ ) is connected; the other end of the third capacitor ( C ₃ ) is connected with the other end of the first inductor ( L ₁ ) and the anode of the third diode ( D ₃ ); the The cathode of the third diode ( D ₃ ) and the other end of the second inductor ( L ₂ ), the other end of the second capacitor ( C ₂ ), the drain of the switch tube ( S ) and the fourth diode ( D ₄ ) connected to the anode; the cathode of the fourth diode ( D ₄ ) is connected to one end of the output capacitor ( C _out ) and one end of the load; the output capacitor ( C _out ) is connected in parallel with the load; the DC input The negative pole of the power supply is connected to the other end of the first capacitor ( C ₁ ), the source of the switch tube ( S ), the other end of the output capacitor ( C _out ) and the other end of the load.