Quasi-Z-type coupling inductor direct-current boost converter

Abstract

The invention discloses a quasi-Z-type coupling inductor direct-current boost converter, and relates to the field of power electronic converters. The invention aims to solve the problems of low voltage gain and high element voltage stress of the traditional Z-source impedance network boost converter. According to the quasi-Z-type coupling inductor direct current boost converter, high voltage gain can be realized, voltage and current stress of a power element can be effectively reduced, input current ripples can be reduced, efficiency and power density of the converter can be improved, and electromagnetic interference can be reduced. By introducing the structure of the coupling inductor, multiple defects of a traditional direct current boost converter can be overcome, the requirements of modern power electronic equipment for high performance, high reliability, high power density and low electromagnetic interference are met, and the voltage gain is greatly improved.

Description

Technical Field

[0001] The invention belongs to the field of power electronic converters. Background Art

[0002] A boost converter, also known as a boost converter or boost chopper, is a DC-DC converter that can increase voltage. Its output (load) voltage will be higher than the input (power supply) voltage. Boost converters are widely used in the pre-converter of distributed power systems to achieve the boost function. It can effectively reduce the voltage and current stress of power components, reduce input current ripple, improve the efficiency and power density of the converter, and reduce electromagnetic interference while achieving high voltage gain.

[0003] The traditional Z-source network circuit topology is a quasi-Z-type coupled inductor impedance network. The boost converter of this network has the problems of low voltage gain and high component voltage stress, resulting in low energy efficiency conversion. Therefore, its boost capability is very limited and is not suitable for high voltage gain DC power conversion occasions. Summary of the invention

[0004] The present invention aims to solve the problems of low voltage gain and high component voltage stress in a traditional Z-source impedance network boost converter, and provides a quasi-Z-type coupled inductor DC boost converter.

[0005] A quasi-Z-type coupled inductor DC boost converter, comprising: an inductor L1, diodes D1-D4, an output diode D o , capacitor C1, output capacitor C o , power switch tube S and coupled inductor windings N1, N2;

[0006] One end of the inductor L1 is used as the positive connection end of the power supply, the other end of the inductor L1 is connected to the positive electrodes of the diodes D1 and D2 respectively, the cathode of the diode D1 is connected to the positive electrode of the coupled inductor winding N1 and one end of the capacitor C1 respectively, the cathode of the diode D2 is connected to the positive electrode of the diode D3, the negative electrode of the coupled inductor winding N1, the drain of the power switch tube S and the positive electrode of the diode D4 respectively, the cathode of the diode D3 is connected to the output diode D o The cathode of the diode D4 is connected to the anode of the coupled inductor winding N2, and the cathode of the output diode D o The negative terminal of the output capacitor C o One end of the output capacitor C o The other end of the capacitor C1 and the source of the power switch tube S are all used as the negative connection end of the power supply. o The two ends of the load are used as the connection ends.

[0007] Furthermore, the voltage gain G of the quasi-Z-type coupled inductor DC boost converter is expressed as:

[0008]

[0009] Wherein, D is the conduction duty cycle of the power switch tube S, and n1 is the turns ratio of the coupled inductor.

[0010] Furthermore, the on-duty cycle of the power switch tube S has a value range of (0, 1).

[0011] Furthermore, the expression of the turns ratio n1 of the above coupled inductor is:

[0012] n1=N2:N1,

[0013] Among them, N1 and N2 are the turns of the two windings of the coupled inductor respectively.

[0014] Furthermore, the operating modes of the quasi-Z-type coupled inductor DC boost converter include: the power switch tube S is turned on and the power switch tube S is turned off.

[0015] The quasi-Z-type coupled inductor DC boost converter described in the present invention can effectively reduce the voltage and current stress of power components, reduce input current ripple, improve the efficiency and power density of the converter, and reduce electromagnetic interference while achieving high voltage gain. By introducing the coupled inductor structure, many defects of traditional DC boost converters can be overcome to meet the requirements of modern power electronic equipment for high performance, high reliability, high power density and low electromagnetic interference, and greatly improve voltage gain. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the circuit structure of a quasi-Z-type coupled inductor DC boost converter;

[0017] Figure 2 The equivalent circuit diagram of the quasi-Z-type coupled inductor DC boost converter, where (a) indicates the switch is turned on and (b) indicates the switch is turned off;

[0018] Figure 3 When the input voltage V in =50V, output voltage V o =250V experimental waveform, where (a) represents the output capacitor voltage V o and input voltage V in Waveform curves, (b) represents the power switch tube voltage and the output diode voltage waveform curve, (c) represents the inductor L1 current and the coupled inductor winding N1 current waveform curve, (d) represents the capacitor C1 voltage and the diode D2 voltage waveform curve. DETAILED DESCRIPTION

[0019] The following will be combined with the accompanying 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, rather than 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 belong to the scope of protection of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0020] Reference Figures 1 to 3 Specifically describe this embodiment, a quasi-Z-type coupled inductor DC boost converter described in this embodiment includes: an inductor L1, diodes D1-D4, an output diode D o , capacitor C1, output capacitor C o , power switch tube S, coupled inductor windings N1 and N2.

[0021] like Figure 1 As shown, one end of the inductor L1 is connected to a DC voltage source V in The other end of the inductor L1 is connected to the positive electrode of the diodes D1 and D2 respectively. The cathode of the diode D1 is connected to the positive electrode of the coupled inductor winding N1 and one end of the capacitor C1 respectively. The cathode of the diode D2 is connected to the positive electrode of the diode D3, the negative electrode of the coupled inductor winding N1, the drain of the power switch tube S and the positive electrode of the diode D4 respectively. The cathode of the diode D3 is connected to the output diode D o The positive electrode of the diode D4 is connected to the negative electrode of the coupled inductor winding N2, and the cathode of the diode D4 is connected to the positive electrode of the coupled inductor winding N2. o The negative terminal of the output capacitor C o One end of the output capacitor C o The other end of the capacitor C1 and the source of the power switch tube S are connected to the DC voltage source V in The output capacitor C o A load R is connected in parallel at both ends.

[0022] The working principle and working process of a quasi-Z-type coupled inductor DC boost converter described in this embodiment are as follows:

[0023] The control signal of the quasi-Z-type coupled inductor DC boost converter is V gs , used to control the on and off of the power switch tube S. Its working process is divided into two switching modes: the power switch tube S is turned on and the power switch tube S is turned off. The specific description is as follows:

[0024] When the power switch tube S is turned on, the equivalent circuit is as follows: Figure 2 As shown in (a), the DC voltage V inDirectly connected to the inductor L1, the diode D1 is reverse biased and cut off, the diode D2 is turned on, and the capacitor C1 charges the coupled inductor winding N1. Output diode D o Reverse bias, output capacitor C o The load R is powered independently and this mode ends.

[0025] When the power switch tube S is turned off, the equivalent circuit is as follows: Figure 2 As shown in (b), diodes D2 and D3 are reverse biased and cut off, while diodes D1 and D4 are forward biased and turned on. in The capacitor C1 is charged through the inductor L1. The DC voltage V in , inductor L1 and coupled inductor windings N1 and N2 are connected through output diode D o to the load R and output capacitor C o Power is supplied and this mode ends.

[0026] From the above analysis, the expression of voltage gain G can be obtained as:

[0027]

[0028] Wherein, D is the on-duty cycle of the power switch tube S, and its operating range is (0,1), n1 is the turns ratio of the coupled inductor, and n1=N2:N1.

[0029] like Figure 3 As shown, the input DC voltage V in =50V, output capacitor voltage V o =250V, the turns ratio of the coupled inductor n1=2, the load R=200Ω; Figure 3 (a) represents the output capacitor voltage V o and input voltage V in ; Figure 3 (b) represents the power switch tube voltage and output diode voltage; Figure 3 (c) represents the current of inductor L1 and coupled inductor winding N1. Figure 3 (d) is the voltage of capacitor C1 and diode D2. As can be seen from the figure, the quasi-Z-coupled inductor DC boost converter has a very high voltage output gain.

[0030] 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 quasi-Z-type coupled inductor DC boost converter, characterized in that: include: Inductor L1, diodes D1~D4, output diode D o , capacitor C1, output capacitor C o , power switch tube S and coupled inductor windings N1, N2; One end of the inductor L1 is used as the positive connection end of the power supply, the other end of the inductor L1 is connected to the positive electrodes of the diodes D1 and D2 respectively, the cathode of the diode D1 is connected to the positive electrode of the coupled inductor winding N1 and one end of the capacitor C1 respectively, the cathode of the diode D2 is connected to the positive electrode of the diode D3, the negative electrode of the coupled inductor winding N1, the drain of the power switch tube S and the positive electrode of the diode D4 respectively, the cathode of the diode D3 is connected to the output diode D o The cathode of the diode D4 is connected to the anode of the coupled inductor winding N2, and the cathode of the output diode D o The negative terminal of the output capacitor C o One end of the output capacitor C o The other end of the capacitor C1 and the source of the power switch tube S are all used as the negative connection end of the power supply. o The two ends of the load are used as the connection ends.

2. The quasi-Z-type coupled inductor DC boost converter according to claim 1, characterized in that: The voltage gain G of the quasi-Z-type coupled inductor DC boost converter is expressed as: Wherein, D is the conduction duty cycle of the power switch tube S, and n1 is the turns ratio of the coupled inductor.

3. The quasi-Z-type coupled inductor DC boost converter according to claim 2, characterized in that: The conduction duty cycle of the power switch tube S ranges from (0 to 1).

4. A quasi-Z-type coupled inductor DC boost converter according to claim 2 or 3, characterized in that: The expression of the turns ratio n1 of the coupled inductor is: n1=N2:N1, Among them, N1 and N2 are the turns of the two windings of the coupled inductor respectively.

5. The quasi-Z-type coupled inductor DC boost converter according to claim 1, characterized in that: The operating modes of the quasi-Z-type coupled inductor DC boost converter include: the power switch tube S is turned on and the power switch tube S is turned off.

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