CN105529918A - A High Gain Trans-Z Source Boost Converter - Google Patents

Abstract

The invention provides a high-gain Trans-Z source boost converter. The converter comprises a direct-current input power supply Vin, a first inductor (L1), a first diode (D1), a first capacitor (C1), a second capacitor (C2), a third capacitor (C3), a second diode (D2), a transformer (T) with the turn ratio of 1 to n, a switch tube (S), a third diode (D3), an output capacitor (Cout) and a load. The converter is mainly characterized in that a positive electrode of the direct-current input power supply Vin is connected with one end of the first inductor (L1). Compared with a Boost converter, a quasi Z source converter and the like, the high-gain Trans-Z source boost converter has a higher voltage gain, and is suitable for the occasion of non-isolating high-gain direct-current voltage conversion.

Description

A High Gain Trans-Z Source Boost Converter

technical field

The invention relates to the field of DC/DC converters, in particular to a high-gain Trans-Z source step-up converter.

Background technique

The development of renewable energy power generation systems such as photovoltaics and fuel cells has become one of the important means to solve the shortage of fossil fuels and protect the environment. However, the output voltage of photovoltaics and fuel cells is very low, and DC/DC converters are generally required to boost the voltage. However, many step-up DC/DC converters are limited by duty cycle, heat generation and loss, and cannot achieve a large boost. For example, Boost converters have a voltage gain of 1/(1-D), where D is the duty cycle ratio, but due to the influence of parasitic parameters, its gain is limited; another example is the quasi-Z source converter, its voltage gain is 1/(1-2D), which has a certain improvement compared with the Boost converter, but there is still room for improvement .

Contents of the invention

The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art, and propose a high-gain Trans-Z source boost converter.

The circuit of the present invention specifically includes DC input power V _in , the first inductor, the first diode, the first capacitor, the second capacitor, the third capacitor, and the second diode The above, the transformer with a turn ratio of 1:n (n≥2), the switch tube, the third diode, the output capacitor and the load.

The specific connection mode of the circuit of the present invention is: the positive pole of the DC input power source V _in is connected to the one end of the first inductor. The other end of the first inductor is connected to the anode of the first diode and the one end of the second capacitor. The cathode of the first diode is connected with the one end of the first capacitor, the one end of the third capacitor and the anode of the second diode. The cathode of the second diode is connected to the same terminal of the secondary side of the transformer. The opposite end of the secondary side of the transformer is connected to the other end of the third capacitor and the same end of the primary side of the transformer. The opposite end of the primary side of the transformer is connected to the other end of the second capacitor, the drain of the switch tube and the anode of the third diode. The cathode of the third diode is connected to the 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 prior art, the advantage that circuit of the present invention has is: compared with traditional Boost converter (its output voltage is ) and a quasi-Z source converter (whose 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 present invention 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 circuit of the present invention has the advantages of Very broad application prospects.

Description of drawings

Figure 1 is a structural diagram of a high-gain Trans-Z source boost converter.

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, Boost and quasi-Z source converter as the duty cycle D changes.

detailed description

The present invention will be described in further detail in conjunction with the following examples and accompanying drawings, but the embodiments of the present invention are 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 present invention and the reference directions of voltage and current of each main component are shown in FIG. 1 . For the convenience of analysis, the devices in the circuit structure are regarded as ideal devices. The driving signal v _GS of the switch 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 _L1 of the first inductor L ₁ , the waveforms of the excitation inductance L _m current i _Lm of the transformer T, the voltage V _C1 of the first capacitor C ₁ , the voltage V _C2 of the second capacitor C ₂ , and the voltage V _C3 of the third capacitor C ₃ are shown in FIG. 2 .

In the t ₀ ~ t ₁ stage, 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 first two The diode D ₁ , the second diode D ₂ and the third diode D ₃ are cut off under reverse voltage. The DC input power supply V _in and the _second capacitor C2 charge the _first inductor L1 through the switch S at the same time, and the first capacitor _C1 and the _third capacitor C3 charge the excitation inductance L _m of the transformer T through the switch S 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, and the switch tube S is turned off. The pole diode D ₁ , the second diode D ₂ and the third diode D ₃ are turned on under forward voltage. The DC input power supply V _in and the first inductor L ₁ simultaneously supply the first capacitor C ₁ , the second capacitor C ₂ , the third capacitor C ₃ , and the output capacitor C through the first diode D ₁ and the third diode D _{3 out} and the load, the excitation inductance L _m of the transformer T simultaneously charges the first capacitor C ₁ , the second capacitor C ₂ , the third capacitor C ₃ , and the output capacitor through the first diode D ₁ and the second diode D ₂ C _out and load charging. In addition, the DC input power source V _in , the first inductance L ₁ and the excitation inductance L _m of the transformer T simultaneously feed the output capacitor C through the first diode D ₁ , the second diode D ₂ and the third diode D _{3 out} and load charging.

The steady-state gain of the circuit of the present invention is derived as follows.

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.

(V _in +V _C2 )t _on +(V _in -V _C1 )t _off =0(1)

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

$<span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

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

V _out =V _C1 +V _C2 (4)

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 .

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

The steady-state gains of the traditional Boost converter and the quasi-Z source converter are 1/(1-D) and (1-D)/(1-2D) respectively (D is the duty cycle), when the turn ratio n=2 , the steady-state gain comparison diagram of the proposed circuit of the present invention and the Boost converter and the quasi-Z source converter is shown in Figure 4, as can be seen from Figure 4, when the input voltage is 10V, the circuit proposed by the present invention only needs the duty cycle If it is 0.24, it can be raised to about 250V, while the other two converters require a larger duty cycle.

Claims (2)

1. A high-gain Trans-Z source boost converter, characterized in that it includes a DC input power supply, a first inductor (L ₁ ), a first diode (D ₁ ), a first capacitor (C ₁ ), and a first The second capacitor (C ₂ ), the third capacitor (C ₃ ), the second diode (D ₂ ), the transformer (T) with a turn ratio of 1:n, the switch tube (S), the third diode (D ₃ ), output capacitor (C _out ) and load; The anode of the DC input power supply is connected to one end of the first inductor (L ₁ ); the other end of the first inductor (L ₁ ) is connected to the anode of the first diode (D ₁ ) and the second capacitor (C ₂ ) is connected to one end; the cathode of the first diode (D ₁ ) is connected to one end of the first capacitor (C ₁ ), one end of the third capacitor (C ₃ ) and the anode of the second diode (D ₂ ) connection; the cathode of the second diode (D ₂ ) is connected to the same-named end of the secondary side of the transformer (T); the opposite-named end of the secondary side of the transformer (T) is connected to the other end of the third capacitor (C ₃ ) Connect with 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 other end of the second capacitor (C ₂ ), the drain of the switch tube (S) and the third diode (D ₃ ) anode connection; the cathode of the third diode (D ₃ ) 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 The negative pole of the DC input power source V _in is connected with 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. 2. a kind of high-gain Trans-Z source step-up converter as claimed in claim 1 is characterized _in that the relation of output voltage V _out and DC input voltage Vin is: , D is the duty cycle.