CN105490536A - High-gain voltage-lifting quasi Z source converter - Google Patents

Abstract

The invention provides a high-gain voltage lift quasi-Z source converter. The converter includes a DC input power supply, a first inductor, a first capacitor, a first diode, a second capacitor, a second inductor, a second diode, a third capacitor, a fourth capacitor, and a third diode , the third inductor, the fifth capacitor, the fourth inductor, the fourth diode, the switch tube, the fifth diode, the output capacitor and the load. Compared with Boost converters, voltage-lifting quasi-Z source converters and the like, the present invention has higher voltage gain, and is suitable for non-isolated high-gain DC voltage conversion occasions.

Description

A High Gain Voltage Lifting Quasi-Z Source Converter

technical field

The invention relates to the field of DC/DC converters, in particular to a high-gain voltage lift quasi-Z source converter.

Background technique

Today, with energy depletion and environmental pollution becoming more and more serious, solar energy, as a renewable and clean energy, has increasingly attracted widespread attention from the international community. Solar photovoltaic power generation has become one of the most important ways to utilize solar energy today. The output voltage level of photovoltaic array batteries is low, which cannot meet the power supply requirements of existing electrical equipment, nor can it meet the requirements of grid connection. Therefore, the output voltage of photovoltaic array batteries must be boosted by a DC/DC converter before use. Up to now, a variety of high-gain DC/DC converters have appeared, but many step-up DC/DC converters are limited by duty cycle, heat generation and loss, and cannot achieve a large boost, such as Boost converters , its voltage gain is 1/(1-D), and D is the duty cycle, but due to the influence of parasitic parameters, its gain is limited; another example is the voltage boost quasi-Z source converter, its voltage gain is 2/( 1-3D), which has been greatly improved 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 voltage-lift quasi-Z source converter.

The circuit of the present invention specifically includes a DC input power supply V _in , a first inductor, a first capacitor, a first diode, a second capacitor, a second inductor, a second diode, a third capacitor, a fourth capacitor, a third A diode, a third inductor, a fifth capacitor, a fourth inductor, a fourth diode, a switch tube, a fifth diode, an output capacitor and a load.

The specific connection mode of the circuit of the present invention is as follows: the positive pole of the DC input power supply V _in is connected to one end of the first inductor and one end of the first capacitor. The other end of the first inductor is connected to the anode of the first diode and one end of the second capacitor. The cathode of the first diode is connected with the other end of the first capacitor and one end of the second inductor. The other end of the second capacitor is connected with the other end of the second inductor, the anode of the second diode and one end of the fourth capacitor. The cathode of the second diode is connected with one end of the third capacitor, the anode of the third diode and one end of the third inductor. The cathode of the third diode is connected with one end of the fifth capacitor and one end of the fourth inductor. The other end of the fifth capacitor is connected to the other end of the third inductor and the anode of the fourth diode. The other end of the fourth inductance is connected with the cathode of the fourth diode, the other end of the fourth capacitor, the drain of the switching tube and the anode of the fifth diode. The cathode of the fifth 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 third 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 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 present invention can raise the low-level voltage to a high-level voltage only with a small duty cycle, and the input and output share the same ground, so the circuit of the present invention has a wide range of applications prospect.

Description of drawings

Figure 1 is a structure diagram of a high-gain voltage-lift quasi-Z source 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 a waveform diagram of the gain V _out /V _in of the proposed circuit, Boost and voltage-lift quasi-Z source converters as a function of the duty cycle D.

detailed description

The present invention will be described in further detail below in conjunction with the embodiments 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 topology of this example and the voltage and current reference direction of each main component are shown in Figure 1. For the convenience of verification, the devices in the circuit structure are regarded as ideal devices. In the circuit, 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 , and the current i _D3 of the fourth diode D 1 D ₄ current i _D4 , fifth diode D ₅ current i _D5 , first inductor L ₁ current i _L1 , second inductor L ₂ current i _L2 , third inductor L ₃ current i _L3 , fourth inductor L ₄ current Waveform diagrams of i _L4 , the voltage V C1 of the first capacitor C ₁ , the voltage V _C2 of the second capacitor C ₂ , the voltage V _C3 of the third capacitor C ₃ , the voltage V _C4 of the fourth capacitor _{C 4} , and the voltage V _C5 of the fifth capacitor C ₅ as shown in picture 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 third and second The diode D ₃ and the fourth diode D ₄ are turned on under the forward voltage, and the first diode D ₁ , the second diode D ₂ and the fifth diode D ₅ are turned off under the reverse voltage. The DC input power V _in , the second capacitor C ₂ and the fourth capacitor C ₄ charge the first inductor L ₁ at the same time through the switch tube S, and the DC input power V _in , the first capacitor C ₁ and the fourth capacitor C ₄ pass through the switch tube S S charges the second inductance L ₂ at the same time, and the third capacitor C ₃ charges the _{third inductance L 3 ,} the _{fourth inductance L 4 and} the Five capacitors _{C5 are} charged. 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 third and second The diode D ₃ and the fourth diode D ₄ are turned off under reverse voltage, and the first diode D ₁ , second diode D ₂ and fifth diode D ₅ are turned on under forward voltage. The first inductor L ₁ charges the first capacitor C ₁ through the first diode D ₁ , the second inductor L ₂ charges the second capacitor C ₂ through the first diode D ₁ , the DC input power supply V _in , the first The inductance L ₁ and the second inductance L ₂ simultaneously charge the third capacitor C ₃ through the first diode D ₁ and the second diode D ₂ , the third inductance L ₃ , the fourth inductance L ₄ and the fifth capacitor C ₅ Charge the _fourth capacitor _C4 through the _second diode D2, the third diode _D3 and the fourth diode D4. In addition, the DC input power supply V _in , the first inductor L ₁ , the second inductor L ₂ , the third inductor L ₃ , the fourth inductor L ₄ and the fifth capacitor C ₅ pass through the first diode D ₁ , the second diode _The tube D2 and the _fifth diode D5 supply power to the output capacitor C _out and the load at the same time.

The steady-state gain derivation of this example circuit:

Since the inductance values of the _first inductance L1 and the _second inductance L2 are equal, the inductance values of the _third inductance L3 and the _fourth inductance L4 are equal, and the capacitance values of the first capacitor _C1 and the _second capacitor C2 are equal, then The voltage and current of the _first inductor L1 and the _second inductor L2 are equal, the voltage and current of the _third inductor L3 and the _fourth inductor L4 are equal, and the voltage and current of the first capacitor _C1 and the _second capacitor C2 are equal .

Since the average value of the voltages of the first inductor L ₁ , the second inductor L ₂ , the third inductor L ₃ , and the fourth inductor L ₄ is zero within one switching cycle, the following relationship can be obtained.

$<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; f</span>}\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 4</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; f</span>}\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

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

V _out =V _C3 +V _C4 (3)

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

${\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; u</span>}\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 5</span>}\mathrm{<span\; class="notranslate">\; D.</span>}}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

The steady-state gains of the traditional Boost converter and the voltage-lift quasi-Z source converter are 1/(1-D) and 2/(1-3D) respectively (D is the duty cycle), and the circuit proposed in this embodiment is the same as The steady-state gain comparison diagrams of Boost converters and voltage-lift quasi-Z source converters are shown in Figure 4. From Figure 4, it can be seen that when the input voltage is 10V, the circuit proposed by the present invention only needs a duty ratio of 0.16 to It can be raised to about 100V, while the other two converters require a larger duty cycle.

Claims (2)

1. A high-gain voltage-lift quasi-Z source converter, including a DC input power supply, a first inductor ( L ₁ ), a first capacitor ( C ₁ ), a first diode ( D ₁ ), and a second capacitor ( C ₂ ), the second inductor ( L ₂ ), the second diode ( D ₂ ), the third capacitor ( C ₃ ), the fourth capacitor ( C ₄ ), the third diode ( D ₃ ), the Three inductors ( L ₃ ), fifth capacitor ( C ₅ ), fourth inductor ( L ₄ ), fourth diode ( D ₄ ), switch tube ( S ), fifth diode ( D ₅ ), 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 ) and one end of the first capacitor ( C ₁ ); the other end of the first inductor ( L ₁ ) is connected to the first diode ( D ₁ ) is connected to one end of the second capacitor ( C ₂ ); the cathode of the first diode ( D ₁ ) is connected to the other end of the first capacitor ( C ₁ ) and one end of the second inductor ( L ₂ ). ; The other end of the second capacitor ( C ₂ ) is connected to the other end of the second inductor ( L ₂ ), the anode of the second diode ( D ₂ ) and one end of the fourth capacitor ( C ₄ ); the The cathode of the second diode ( D ₂ ) is connected to one end of the third capacitor ( C ₃ ), the anode of the third diode ( D ₃ ) and one end of the third inductor ( L ₃ ); the third two The cathode of the pole tube ( D ₃ ) is connected to one end of the fifth capacitor ( C ₅ ) and one end of the fourth inductor ( L ₄ ); the other end of the fifth capacitor ( C ₅ ) is connected to the third inductor ( L ₃ ) The other end of the fourth diode ( D ₄ ) is connected to the anode of the fourth diode ( D 4 ); the other end of the fourth inductor ( L ₄ ) is connected to the cathode of the fourth diode ( D ₄ ) and the fourth capacitor ( C ₄ ) The other end, the drain of the switch tube ( S ) is connected to the anode of the fifth diode ( D ₅ ); the cathode of the fifth diode ( D ₅ ) is connected to one end of the output capacitor ( C _out ) and the load Connected at one end; the output capacitor ( C _out ) is connected in parallel with the load; the negative pole of the DC input power supply is connected to the other end of the third capacitor ( C ₃ ), the source of the switch tube ( S ), and the output capacitor ( C _out ) The other end is connected to the other end of the load. 2. a kind of high-gain voltage lifting type quasi-Z source converter according to claim 1 is characterized _in that the relation of output voltage V _out and DC input voltage Vin is: , D is the duty cycle.