Switched inductor series connection type quasi-Z-source direct current boost converter

Abstract

The invention discloses a switch inductor series connection type quasi-Z-source direct current boost converter, belongs to the field of power electronic converters, and aims to solve the problem that a traditional Z source is not suitable for a high boost gain conversion scene. By utilizing the energy storage and release characteristics of the inductor and the capacitor, high direct-current voltage can still be output under the condition that the input voltage is low, and the requirements of low-voltage input and high-voltage output in a renewable energy power generation system are met. The switch inductor series connection type quasi-Z-source direct current boost converter comprises a direct current voltage source, four same inductor units, seven diode units, two capacitor units and a direct current converter output unit, wherein a switch inductor is composed of L1, L2, D1, D3, L3, L4, D5 and D7. The DC converter output unit is composed of an output diode, an output capacitor and a load. The switch inductor series connection type quasi Z source can provide high voltage gain.

Description

Technical Field

[0001] The invention relates to a switch inductor series type quasi-Z source direct current boost converter, belonging to the field of power electronic converters. Background Art

[0002] Boost converters are widely used as pre-converters in distributed power systems to achieve boost functions. The switched inductor series quasi-Z source DC boost converter can achieve high gain boost at a relatively low duty cycle through a unique topology. It utilizes the energy storage and release characteristics of inductors and capacitors, and can still output a higher DC voltage when the input voltage is low, meeting the requirements of low voltage input and high voltage output in renewable energy power generation systems. However, traditional Z sources have abnormal operating modes, low boost capabilities, and startup impact circuits that can damage components. In addition, excessive duty cycles can also lead to excessive energy loss, so the boost performance is not ideal and is not suitable for high boost gain conversion scenarios. Summary of the invention

[0003] In view of the problem that the traditional Z source is not suitable for high boost gain conversion scenarios, the present invention provides a switch inductor series type quasi-Z source DC boost converter.

[0004] The invention discloses a switch inductor series type quasi-Z source DC boost converter, comprising a DC voltage source V in , inductor group No. 1, inductor group No. 2, capacitor No. 1 C1, capacitor No. 2 C2, power switch tube S and output unit;

[0005] When the power switch tube S is turned on, the DC voltage source V in The No. 1 capacitor C1 charges the No. 1 inductor group, and the No. 2 capacitor C2 charges the No. 2 inductor group; the output unit is powered independently;

[0006] When the power switch tube S is turned off, the No. 1 inductor group charges the No. 2 capacitor C2, and the No. 2 inductor group charges the No. 1 capacitor C1 and supplies power to the output unit;

[0007] The voltage gain G of the converter is obtained as:

[0008]

[0009] Where D is the on-duty cycle of the power switch tube S, and the value range of D is (0, 0.33).

[0010] Preferably, the first inductor group includes inductors L1 and L2, the second inductor group includes inductors L3 and L4, and the output unit includes an output diode D o , output capacitor C o and load R; the converter also includes diodes D1 to D7;

[0011] DC voltage source V in The positive electrode of the diode D1 is connected to the positive electrode of the diode D1 and the positive electrode of the inductor L1 at the same time, the negative electrode of the diode D2 is connected to the positive electrode of the inductor L2 and the negative electrode of the diode D1 at the same time, and the positive electrode of the diode D2 is connected to the negative electrode of the inductor L1 and the positive electrode of the diode D3 at the same time; the positive electrode of the diode D4 is connected to the negative electrode of the diode D3, the negative electrode of the inductor L2 and the positive electrode of the capacitor C1 at the same time, and the positive electrode of the diode D5 is connected to the negative electrode of the diode D4, the positive electrode of the inductor L3 and the positive electrode of the capacitor C2 at the same time; the positive electrode of the diode D6 is connected to the negative electrode of the inductor L3 and the positive electrode of the diode D7 at the same time, and the negative electrode of the diode D6 is connected to the negative electrode of the diode D5 and the positive electrode of the inductor L4 at the same time, and the negative electrode of the capacitor C1 is connected to the negative electrode of the inductor L4, the negative electrode of the diode D7, and the output diode D o The positive electrode is connected to the drain of the power switch tube S; the output diode D o The negative electrode of the output capacitor C o The positive electrode is connected to one end of the load R, and the output capacitor C o The negative electrode of the resistor R, the source of the power switch tube S, and the negative electrode of the capacitor C2 are connected to the DC voltage source V in The negative pole is connected.

[0012] Preferably, the inductor L1 , the inductor L2 , the diode D1 , the diode D3 , the inductor L3 , the inductor L4 , the diode D5 and the diode D7 constitute a switching inductor.

[0013] Preferably, the inductor L1 , the inductor L2 , the inductor L3 and the inductor L4 have the same inductance.

[0014] Preferably, the diodes D1 to D7 are identical diodes.

[0015] Beneficial effects of the present invention: The boost converter of the present invention can achieve high-gain boost at a relatively low duty cycle. It cleverly utilizes the energy storage and release characteristics of inductors and capacitors, and can still output a higher DC voltage when the input voltage is low, meeting the requirements of low voltage input and high voltage output in renewable energy power generation systems.

[0016] Compared with traditional converters, under the same step-up ratio requirement, the voltage peak borne by the switch device in the present invention is lower, which makes it possible to select switch devices with lower withstand voltage level and lower cost, while also improving the reliability and stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a circuit diagram of a switch inductor series type quasi-Z source DC boost converter according to the present invention;

[0018] Figure 2It is the equivalent circuit diagram of the switch-inductor series quasi-Z source DC boost converter when the switch is turned on;

[0019] Figure 3 It is the equivalent circuit diagram of the switch-inductor series quasi-Z source DC boost converter when the switch is turned off;

[0020] Figure 4-Figure 11 is the input voltage V in =50V, output voltage V o = Experimental waveform at 635V:

[0021] Figure 4 It is the DC input voltage experimental waveform;

[0022] Figure 5 It is the output voltage experimental waveform;

[0023] Figure 6 is the output diode D o Voltage experimental waveform diagram;

[0024] Figure 7 is the power switch voltage V s Experimental waveform diagram;

[0025] Figure 8 This is the experimental waveform of the inductor L1 current;

[0026] Fig. 9 This is the experimental waveform of the capacitor C1 voltage;

[0027] Fig.10 This is the voltage experimental waveform of diode D5;

[0028] Fig.11 This is the diode D1 voltage experimental waveform. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0031] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0032] Specific implementation method 1: The following is combined Figures 1 to 11The present embodiment is described as follows: a switch inductor series type quasi-Z source DC boost converter includes a DC voltage source V in , inductor group No. 1, inductor group No. 2, capacitor No. 1 C1, capacitor No. 2 C2, power switch tube S, diodes D1 to D7 and output unit; inductor group No. 1 includes inductor L1 and inductor L2, inductor group No. 2 includes inductor L3 and inductor L4, and the output unit includes output diode D o , output capacitor C o and load R;

[0033] The inductor L1, the inductor L2, the diode D1, the diode D3, the inductor L3, the inductor L4, the diode D5 and the diode D7 constitute a switching inductor.

[0034] In the two modes of the power switch tube S being turned on and off, the switch inductor acts accordingly, cleverly utilizing the energy storage and release characteristics of the inductor and capacitor, and can still output a higher DC voltage when the input voltage is low, meeting the requirements of low voltage input and high voltage output in renewable energy power generation systems. The switch inductor series quasi-Z source of the present invention can provide a higher voltage gain.

[0035] DC voltage source V in The positive electrode of the diode D1 is connected to the positive electrode of the diode D1 and the positive electrode of the inductor L1 at the same time, the negative electrode of the diode D2 is connected to the positive electrode of the inductor L2 and the negative electrode of the diode D1 at the same time, and the positive electrode of the diode D2 is connected to the negative electrode of the inductor L1 and the positive electrode of the diode D3 at the same time; the positive electrode of the diode D4 is connected to the negative electrode of the diode D3, the negative electrode of the inductor L2 and the positive electrode of the capacitor C1 at the same time, and the positive electrode of the diode D5 is connected to the negative electrode of the diode D4, the positive electrode of the inductor L3 and the positive electrode of the capacitor C2 at the same time; the positive electrode of the diode D6 is connected to the negative electrode of the inductor L3 and the positive electrode of the diode D7 at the same time, and the negative electrode of the diode D6 is connected to the negative electrode of the diode D5 and the positive electrode of the inductor L4 at the same time, and the negative electrode of the capacitor C1 is connected to the negative electrode of the inductor L4, the negative electrode of the diode D7, and the output diode D o The positive electrode is connected to the drain of the power switch tube S; the output diode D o The negative electrode of the output capacitor C o The positive electrode is connected to one end of the load R, and the output capacitor C o The negative electrode of the resistor R, the source of the power switch tube S, and the negative electrode of the capacitor C2 are connected to the DC voltage source V in The negative pole is connected.

[0036] The inductor L1 , the inductor L2 , the inductor L3 and the inductor L4 use the same inductor.

[0037] Diodes D1 to D7 use the same diodes.

[0038] The power switch tube S adopts NMOS tube.

[0039] The working principle and working process of the present invention are as follows:

[0040] The switch inductor series quasi-Z source DC boost converter of the present invention is a gate of the power switch tube S connected to the control signal V gs , which controls the on and off of the power switch tube S. The parameters formed by each component during the working process include: the inductor current i L1 、i L2 、i L3 、i L4 , the voltage of diode D1 is V D1 , the voltage of diode D2 is V D2 , the voltage of diode D3 is V D3 , the voltage of diode D4 is V D4 , the voltage of diode D5 is V D5 , the voltage of diode D6 is V D6 , the voltage of diode D7 is V D7 , the voltage of capacitor C1 is V C1 , the voltage of capacitor C2 is V C2 , output diode D o The voltage V Do , the drain-source voltage of the power switch tube is V S , its working process is divided into two switching modes: switch on and switch off, which are described as follows:

[0041] When the switch is turned on, the equivalent circuit is as follows Figure 2 As shown, in this stage, the power switch tube S is turned on and the DC voltage V in The inductor L2 is charged through the diode D1, and the DC voltage V in Directly connect the inductor L1 to charge it, the diode D2 is reverse biased and cut off, D3 is turned on, and the DC voltage V in The capacitor C1 charges the inductors L1 and L2. At the same time, the capacitor C2 charges the inductors L3 and L4, the diode D4 is reverse biased and cut off, the diodes D5 and D7 are forward biased and turned on, and the diode D6 is reverse biased and cut off. The output diode D o Reverse bias, output capacitor C o The load resistor R is powered independently and this mode ends.

[0042] When the switch is off, the equivalent circuit is as follows Figure 3 As shown, the power switch tube S remains off, the diode D4 is turned on, the diodes D1 and D3 are reverse biased and cut off, D2 is turned on, the diodes D5 and D7 are reverse biased and cut off, D6 is turned on, and the DC voltage V in , inductors L1 and L2 charge capacitor C2. At the same time, inductors L3 and L4 charge capacitor C1. oto the load R and output capacitor C o Power is supplied and this mode ends.

[0043] According to the above process, the voltage relationship of each component when the switch is turned on and off is obtained, and the voltage gain expression is obtained according to the volt-second balance:

[0044]

[0045] Where D is the conduction duty cycle of the power switch tube S, and its operating range is (0,0.33).

[0046] The following is a description of the beneficial effects of the structure of the present invention through specific experimental data:

[0047] like Figure 4-Figure 11 As shown, the input voltage V in =50V, output voltage V o =635V, D=0.3, load R=200Ω. Figure 4 , 5 The output capacitor voltage is about 635V and the input voltage is 50V. Figure 6 , 7 is the switching diode voltage and the output diode voltage. Figure 8 , 9 Capacitor C1 voltage and inductor L1 current. Fig.10 , 11 is the voltage of diode D4 and the voltage of diode D1. As can be seen from the figure, the switch inductor series quasi-Z source DC boost converter has a very high voltage output gain.

[0048] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that the features described in conjunction with a single embodiment may be used in other described embodiments.

Claims

1. A switch inductor series quasi-Z source DC boost converter, characterized in that: Including DC voltage source V in , inductor group No. 1, inductor group No. 2, capacitor No. 1 C1, capacitor No. 2 C2, power switch tube S and output unit; When the power switch tube S is turned on, the DC voltage source V in The No. 1 capacitor C1 charges the No. 1 inductor group, and the No. 2 capacitor C2 charges the No. 2 inductor group; the output unit is powered independently; When the power switch tube S is turned off, the No. 1 inductor group charges the No. 2 capacitor C2, and the No. 2 inductor group charges the No. 1 capacitor C1 and supplies power to the output unit; The voltage gain G of the converter is obtained as: Where D is the on-duty cycle of the power switch tube S, and the value range of D is (0, 0.33).

2. A switched inductor series quasi-Z source DC boost converter according to claim 1, characterized in that: The first inductor group includes inductors L1 and L2, the second inductor group includes inductors L3 and L4, and the output unit includes an output diode D o , output capacitor C o and load R; the converter also includes diodes D1 to D7; DC voltage source V in The positive electrode of the diode D1 is connected to the positive electrode of the diode D1 and the positive electrode of the inductor L1 at the same time, the negative electrode of the diode D2 is connected to the positive electrode of the inductor L2 and the negative electrode of the diode D1 at the same time, and the positive electrode of the diode D2 is connected to the negative electrode of the inductor L1 and the positive electrode of the diode D3 at the same time; the positive electrode of the diode D4 is connected to the negative electrode of the diode D3, the negative electrode of the inductor L2 and the positive electrode of the capacitor C1 at the same time, and the positive electrode of the diode D5 is connected to the negative electrode of the diode D4, the positive electrode of the inductor L3 and the positive electrode of the capacitor C2 at the same time; the positive electrode of the diode D6 is connected to the negative electrode of the inductor L3 and the positive electrode of the diode D7 at the same time, and the negative electrode of the diode D6 is connected to the negative electrode of the diode D5 and the positive electrode of the inductor L4 at the same time, and the negative electrode of the capacitor C1 is connected to the negative electrode of the inductor L4, the negative electrode of the diode D7, and the output diode D o The positive electrode is connected to the drain of the power switch tube S; the output diode D o The negative electrode of the output capacitor C o The positive electrode is connected to one end of the load R, and the output capacitor C o The negative electrode of the resistor R, the source of the power switch tube S, and the negative electrode of the capacitor C2 are connected to the DC voltage source V in The negative pole is connected.

3. A switched inductor series quasi-Z source DC boost converter according to claim 2, characterized in that: The inductor L1, the inductor L2, the diode D1, the diode D3, the inductor L3, the inductor L4, the diode D5 and the diode D7 constitute a switching inductor.

4. A switched inductor series quasi-Z source DC boost converter according to claim 2, characterized in that: The inductor L1 , the inductor L2 , the inductor L3 and the inductor L4 use the same inductor.

5. The switched inductor series quasi-Z-source DC boost converter according to claim 2, characterized in that: Diodes D1 to D7 use the same diodes.

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