A Novel Wide-Gain Quadratic Buck Converter

Abstract

The present invention relates to the field of power electronic converters and electric energy conversion technology, and in particular to a novel wide-gain quadratic buck converter, comprising a power switch tube, three power inductors, two intermediate energy storage capacitors, an output capacitor, and seven diodes; utilizing the intrinsic characteristics of the inductor-diode and the inductor-diode network, when the power switch tube is turned on, the three power inductors are connected in series and store energy, the two intermediate energy storage capacitors are connected in parallel and release energy to the outside at the same time, and when the power switch tube is turned off, the three power inductors independently release energy to the two intermediate energy storage capacitors and the load, thereby realizing the expansion of the voltage gain of the buck converter. The advantages of the present invention are: the gain of the converter described in the present invention can vary within the range of 0.003-0.669, that is, the output voltage can be as low as 0.003 times the input voltage, which greatly expands the gain range of the traditional buck converter; no additional power switch tube is required, the structure is simple, and the control is convenient.

Description

Technical Field

[0001] The invention relates to the technical field of power electronic converters and electric energy conversion, and in particular to a novel wide-gain quadratic buck converter. Background Art

[0002] The voltage gain variation range of the traditional buck converter is small, and the output voltage is usually only 0.1-0.9 times the input voltage, which is often unable to meet the needs of practical applications. Summary of the invention

[0003] The purpose of the present invention is to provide a novel wide-gain quadratic buck converter based on the above-mentioned deficiencies of the prior art, which utilizes the intrinsic characteristics of an inductor-diode and an inductor-diode network to achieve the expansion of the buck converter gain by switching the on-off state of a power switch tube.

[0004] The purpose of the present invention is achieved by the following technical solutions:

[0005] A novel wide gain quadratic buck converter, characterized in that: it includes an input power supply V g , power switch tube S, first power inductor L1, second power inductor L2, third power inductor L3, first intermediate energy storage capacitor C1, second intermediate energy storage capacitor C2, output capacitor C3, first diode D1, second diode D2, third diode D3, fourth diode D4, fifth diode D5, sixth diode D6, seventh diode D7, load R;

[0006] Among them, the input power supply V g The positive electrode is connected to the cathode of the first diode D1 and one end of the first power inductor L1 respectively;

[0007] The other end of the first power inductor L1 is respectively connected to one end of the first intermediate energy storage capacitor C1, the cathode of the fourth diode D4, and the drain of the power switch tube S;

[0008] The other end of the first intermediate energy storage capacitor C1 is connected to the cathode of the second diode D2 and the anode of the third diode D3 respectively;

[0009] The cathode of the third diode D3 is connected to the anode of the fourth diode D4 and one end of the second intermediate energy storage capacitor C2 respectively;

[0010] The anode of the second diode D2 is respectively connected to the anode of the first diode D1, the other end of the second intermediate energy storage capacitor C2, and the cathode of the fifth diode D5;

[0011] The source of the power switch tube S is connected to one end of the second power inductor L2 and the cathode of the sixth diode D6 respectively;

[0012] The other end of the second power inductor L2 is respectively connected to the cathode of the seventh diode D7, one end of the output capacitor C3, and one end of the load R;

[0013] The anode of the sixth diode D6 is respectively connected to the other end of the load R, the other end of the output capacitor C3, and one end of the third power inductor L3;

[0014] The other end of the third power inductor L3, the anode of the seventh diode D7, the anode of the fifth diode D5 and the input power supply V g negative connection.

[0015] When the power switch tube S is turned on, the input power supply V g The first power inductor L1, the second power inductor L2, and the third power inductor L3 are charged; the first intermediate energy storage capacitor C1 and the second intermediate energy storage capacitor C2 are connected in parallel to charge the second power inductor L2 and the third power inductor L3.

[0016] When the power switch tube S is turned off, the first power inductor L1 releases energy to the first intermediate energy storage capacitor C1 and the second intermediate energy storage capacitor C2 connected in series via the first diode D1 and the third diode D3, the second power inductor L2 provides energy to the load R via the sixth diode D6, and the third power inductor L3 provides energy to the load R via the seventh diode D7.

[0017] The advantages of the present invention are: the gain of the converter can vary within the range of 0.003-0.669, that is, the output voltage can be as low as 0.003 times the input voltage, which greatly expands the gain range of the traditional buck converter; no additional power switch tube is required, the structure is simple, and the control is convenient; by utilizing the inherent characteristics of the inductor-diode and inductor-diode network, when the power switch tube is turned on, the three power inductors are connected in series and store energy, and the two intermediate energy storage capacitors are connected in parallel and release energy to the outside at the same time; when the power switch tube is turned off, the three power inductors independently release energy to the intermediate energy storage capacitors and the load, thereby realizing the expansion of the voltage gain of the buck converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A circuit diagram of an embodiment of the present invention;

[0019] Figure 2 for Figure 1 The circuit diagram shown is a circuit diagram of working mode 1 within a switching cycle;

[0020] Figure 3 for Figure 1 The circuit diagram shown is a circuit diagram of working mode 2 within a switching cycle;

[0021] Figure 2-3 In the figure, the solid line indicates the part of the converter where current flows, and the dotted line indicates the part of the converter where no current flows. Figure 2 The dashed line and arrow direction in the figure represent the direction of current flow in the circuit in working mode 1. Figure 3 The dotted line and arrow direction in the figure represent the direction of current flow in the circuit in working mode 2. DETAILED DESCRIPTION

[0022] The features of the present invention and other related features are further described in detail below through embodiments in conjunction with the accompanying drawings to facilitate understanding by those skilled in the art:

[0023] Embodiment: The novel wide-gain quadratic buck converter in this embodiment utilizes the intrinsic characteristics of an inductor-diode and an inductor-diode network to achieve the expansion of the voltage gain of the buck converter.

[0024] like Figure 1 As shown, the novel wide gain quadratic buck converter in this embodiment includes an input power supply V g , power switch tube S, first power inductor L1, second power inductor L2, third power inductor L3, first intermediate energy storage capacitor C1, second intermediate energy storage capacitor C2, output capacitor C3, first diode D1, second diode D2, third diode D3, fourth diode D4, fifth diode D5, sixth diode D6, seventh diode D7, load R.

[0025] Among them, the input power supply V g The positive electrode is connected to the cathode of the first diode D1 and one end of the first power inductor L1 respectively;

[0026] The other end of the first power inductor L1 is respectively connected to one end of the first intermediate energy storage capacitor C1, the cathode of the fourth diode D4, and the drain of the power switch tube S;

[0027] The other end of the first intermediate energy storage capacitor C1 is connected to the cathode of the second diode D2 and the anode of the third diode D3 respectively;

[0028] The cathode of the third diode D3 is connected to the anode of the fourth diode D4 and one end of the second intermediate energy storage capacitor C2 respectively;

[0029] The anode of the second diode D2 is respectively connected to the anode of the first diode D1, the other end of the second intermediate energy storage capacitor C2, and the cathode of the fifth diode D5;

[0030] The source of the power switch tube S is connected to one end of the second power inductor L2 and the cathode of the sixth diode D6 respectively;

[0031] The other end of the second power inductor L2 is respectively connected to the cathode of the seventh diode D7, one end of the output capacitor C3, and one end of the load R;

[0032] The anode of the sixth diode D6 is respectively connected to the other end of the load R, the other end of the output capacitor C3, and one end of the third power inductor L3;

[0033] The other end of the third power inductor L3, the anode of the seventh diode D7, the anode of the fifth diode D5 and the input power supply V g negative connection.

[0034] like Figure 2 and Figure 3 As shown, the novel wide-gain quadratic buck converter in this embodiment has two main working modes in one cycle, which are described as follows:

[0035] Working mode 1:

[0036] like Figure 2 As shown, the power switch tube S is turned on, the second diode D2, the fourth diode D4, and the fifth diode D5 are turned on, and the first diode D1, the third diode D3, the sixth diode D6, and the seventh diode D7 are turned off. Input power supply V g The first power inductor L1, the second power inductor L2, and the third power inductor L3 are charged, and the first intermediate energy storage capacitor C1 and the second intermediate energy storage capacitor C2 are connected in parallel to charge the second power inductor L2 and the third power inductor L3. Therefore, the three power inductors all store energy in working mode 1, and the two intermediate energy storage capacitors all release energy in working mode 1.

[0037] In this working mode, the relevant electrical parameter relationship can be described as:

[0038] (1)

[0039] (2)

[0040] (3)

[0041] (4)

[0042] in, Indicates the input power supply voltage, V C1 represents the steady-state voltage across the first intermediate energy storage capacitor C1, V C2 Represents the steady-state voltage across the second intermediate energy storage capacitor C2, V ORepresents the steady-state output voltage, V L1 Represents the voltage across the first power inductor L1 in working mode 1, V L2 It represents the voltage across the second power inductor L2 in the working mode. It represents the voltage across the third power inductor L3 in the working mode.

[0043] Working mode 2:

[0044] like Figure 3 As shown, the power switch tube S is turned off, the first diode D1, the third diode D3, the sixth diode D6, and the seventh diode D7 are turned on, and the second diode D2, the fourth diode D4, and the fifth diode D5 are turned off. The first power inductor L1 releases energy to the first intermediate energy storage capacitor C1 and the second intermediate energy storage capacitor C2 connected in series via the first diode D1 and the third diode D3, the second power inductor L2 provides energy to the load R via the sixth diode D6, and the third power inductor L3 provides energy to the load R via the seventh diode D7. Therefore, the three power inductors all release energy in the working mode 2, and the two intermediate energy storage capacitors all store energy in the working mode 2.

[0045] In this working mode, the relevant electrical parameter relationship can be described as:

[0046] (5)

[0047] (6)

[0048] (7)

[0049] (8)

[0050] in, represents the voltage across the first power inductor L1 in the second working mode, It represents the voltage across the second power inductor L2 in the second working mode. It represents the voltage across the third power inductor L3 in the second working mode.

[0051] The voltage gain analysis of the novel wide-gain quadratic buck converter in this embodiment during stable operation is as follows:

[0052] If the switching cycle of the power switch tube S is set to T s , the duty cycle is D, that is, the duration of the working mode is DT S , the duration of working mode 2 is T s .

[0053] According to the inherent volt-second balance characteristics of power inductors, we can get:

[0054] (9)

[0055] (10)

[0056] (11)

[0057] Combining equation (1) and equation (11), we can get:

[0058] (12)

[0059] It can be seen from this that the voltage gain of the novel wide-gain quadratic buck converter in this embodiment is for:

[0060] (13)

[0061] The voltage gain expression of the traditional buck converter is:

[0062] (14)

[0063] From equations (13) and (14), it can be concluded that when the duty cycle When changing within the range of 0.1-0.9, the gain of a conventional buck converter can only change within the range of 0.1-0.9, that is, the output voltage can only reach a minimum of 0.1 times the input voltage, while the gain of the converter described in the present invention can change within the range of 0.003-0.669, that is, the output voltage can reach a minimum of 0.003 times the input voltage, which greatly expands the gain range of conventional buck converters.

[0064] Although the above embodiments have described the concepts and embodiments of the present invention in detail with reference to the accompanying drawings, ordinary technicians in this field can recognize that various improvements and changes can still be made to the present invention without departing from the scope of the claims, so they are not described in detail here.

Claims

1. A novel wide-gain quadratic buck converter, characterized in that: It includes an input power supply Vg, a power switch tube S, a first power inductor L1, a second power inductor L2, a third power inductor L3, a first intermediate energy storage capacitor C1, a second intermediate energy storage capacitor C2, an output capacitor C3, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode D6, a seventh diode D7, and a load R; Wherein, the positive electrode of the input power source Vg is connected to the cathode of the first diode D1 and one end of the first power inductor L1 respectively; The other end of the first power inductor L1 is respectively connected to one end of the first intermediate energy storage capacitor C1, the cathode of the fourth diode D4, and the drain of the power switch tube S; The other end of the first intermediate energy storage capacitor C1 is connected to the cathode of the second diode D2 and the anode of the third diode D3 respectively; The cathode of the third diode D3 is connected to the anode of the fourth diode D4 and one end of the second intermediate energy storage capacitor C2 respectively; The anode of the second diode D2 is respectively connected to the anode of the first diode D1, the other end of the second intermediate energy storage capacitor C2, and the cathode of the fifth diode D5; The source of the power switch tube S is connected to one end of the second power inductor L2 and the cathode of the sixth diode D6 respectively; The other end of the second power inductor L2 is respectively connected to the cathode of the seventh diode D7, one end of the output capacitor C3, and one end of the load R; The anode of the sixth diode D6 is respectively connected to the other end of the load R, the other end of the output capacitor C3, and one end of the third power inductor L3; The other end of the third power inductor L3, the anode of the seventh diode D7, and the anode of the fifth diode D5 are connected to the negative electrode of the input power supply Vg; When the power switch tube S is turned on, the input power supply Vg charges the first power inductor L1, the second power inductor L2, and the third power inductor L3, and the first intermediate energy storage capacitor C1 and the second intermediate energy storage capacitor C2 are connected in parallel to charge the second power inductor L2 and the third power inductor L3; When the power switch tube S is turned off, the first power inductor L1 releases energy to the first intermediate energy storage capacitor C1 and the second intermediate energy storage capacitor C2 connected in series via the first diode D1 and the third diode D3, the second power inductor L2 provides energy to the load R via the sixth diode D6, and the third power inductor L3 provides energy to the load R via the seventh diode D7.

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