Low-cost multi-phase rectifier circuit with reduced diode count

Abstract

The present invention proposes a low-cost multi-phase rectifier circuit with a reduced number of diodes. Considering the prior art solution, as the number of phases increases, the corresponding number of diodes also increases exponentially. When the output is N phases, a total of 4N diodes are required, which will lead to the problem of increased cost and increased loss of the multi-phase rectifier circuit. Therefore, the present invention proposes a multi-phase rectifier circuit that can significantly reduce the number of diodes, thereby reducing the cost of the rectifier circuit and reducing the overall loss.

Description

Technical Field

[0001] The invention belongs to the technical field of multi-phase rectifier circuits, and in particular relates to a low-cost multi-phase rectifier circuit with a reduced number of diodes. Background Art

[0002] A rectifier circuit is a circuit that can convert AC power into DC power. It is widely used in wireless power transmission, automotive industry, railway transportation, DC motor speed regulation, generator excitation regulation, etc. As the power of the rectifier circuit increases further, a multi-phase rectifier circuit can be used to reduce interference to the power grid, improve power factor and pulsation frequency, and significantly reduce the impact of harmonics. In addition, the use of a multi-phase rectifier circuit in a wireless power transmission system can also realize power supply to multiple receiving ends, improving the flexibility of power supply and the overall efficiency of the system.

[0003] The traditional single-phase rectification method is to use 4 rectifier diodes to form a full-wave bridge rectifier circuit, with two diodes forming one bridge arm. For each additional phase of rectification, a rectifier bridge needs to be connected in parallel on the basis of the original one. The schematic diagram of the multi-phase rectification circuit is shown in the attached manual. Figure 1 shown. Summary of the invention

[0004] Considering the existing technical solutions, as the number of phases increases, the number of corresponding diodes also increases exponentially. When the output is N phases, a total of 4N diodes are required, which will lead to the problem of increased cost and loss of the multi-phase rectifier circuit. Therefore, the present invention proposes a multi-phase rectifier circuit that can significantly reduce the number of diodes, thereby reducing the cost of the rectifier circuit and reducing the overall loss.

[0005] The technical solution adopted by the present invention to solve the technical problem is:

[0006] A low-cost multi-phase rectifier circuit with reduced number of diodes is characterized in that: assuming the number of phases is N, N is greater than or equal to 2, and multiple diodes located on different bridge arms are connected in series through inductance across different positions, so that the total number of diodes used in the multi-phase rectifier circuit is 3N or 2N+2.

[0007] Furthermore, the total number of diodes used in the multi-phase rectifier circuit is 3N, which is composed of N bridge arms with 3 diodes connected in series, and each corresponding inductor is connected across the first and second diodes of the adjacent previous bridge arm and the second and third diodes of the next bridge arm.

[0008] Furthermore, the total number of diodes used in the multi-phase rectifier circuit is 2N+2, which is composed of 2 bridge arms each having N+1 diodes connected in series; each corresponding inductor is connected across the corresponding points or mirror points formed by the continuous series connection of two bridge arm diodes.

[0009] Compared with the prior art, the multi-phase rectifier circuit proposed by the present invention and its preferred embodiment can be applied to high-power, low-cost places. Compared with the traditional multi-phase rectifier circuit, it can significantly reduce the number of rectifier diodes and reduce the loss at the output end, thereby achieving greater power transmission and higher efficiency.

[0010] Its advantages include:

[0011] (1) The number of diodes is significantly reduced, which can reduce the cost of the rectifier.

[0012] (2) When used in low voltage and high current applications, it can reduce the loss of the output rectifier diode and improve efficiency.

[0013] (3) The circuit structure is simple and the connection forms are varied. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0015] Figure 1 It is a schematic diagram of a traditional multi-phase rectifier circuit;

[0016] Figure 2 A schematic diagram of a multi-phase rectifier circuit example 1 proposed by the present invention;

[0017] Figure 3 This is a schematic diagram of a two-phase rectifier circuit according to Embodiment 1 of the present invention;

[0018] Figure 4 Schematic diagram of the I1 current flow path of the first embodiment of the present invention, wherein (a) the voltage across L1 is positive; (b) the voltage across L1 is negative;

[0019] Figure 5 Schematic diagram of the I2 current flow path of the first embodiment of the present invention, wherein (a) the voltage across L2 is positive and (b) the voltage across L2 is negative;

[0020] Figure 6 This is a schematic diagram of Example 2 of the multi-phase rectifier circuit proposed by the present invention;

[0021] Figure 7 Schematic diagram of a three-phase rectifier circuit according to a second embodiment of the present invention;

[0022] Figure 8 Schematic diagram of the current flow path of I1 according to the second embodiment of the present invention, (a) when the voltage across L1 is positive (b) when the voltage across L1 is negative;

[0023] Fig. 9 Schematic diagram of the I2 current flow path of the second embodiment of the present invention, (a) when the voltage across L2 is positive (b) when the voltage across L2 is negative;

[0024] Fig.10 This is a schematic diagram of Example 3 of a multi-phase rectifier circuit after changing the connection form proposed by the present invention;

[0025] Fig.11 The third embodiment of the present invention takes N=2 as an example, corresponding to the schematic diagram of the two-phase rectifier circuit, (a) two-phase rectifier circuit (b) when the voltage across L1 is positive (c) when the voltage across L1 is negative;

[0026] Fig.12 Schematic diagram comparing the number of diodes in various multi-phase rectifier circuits according to embodiments of the present invention. DETAILED DESCRIPTION

[0027] In order to make the features and advantages of this patent more obvious and easy to understand, three embodiments are specifically cited below for detailed description as follows:

[0028] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used in this specification have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0029] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0030] Embodiment 1

[0031] An example of a multi-phase rectifier circuit that can reduce the number of diodes proposed by the present invention is as follows Figure 2 shown.

[0032] First, analyze the corresponding circuit when the output phase number N = 2. Figure 3 As shown. Two phases contain two bridge arms, each bridge arm has three diodes, and there are six diodes in total. One end of L1 is connected between diodes D1 and D3, and the other end is connected between D4 and D6; one end of L2 is connected between diodes D2 and D4, and the other end is connected between D3 and D5.

[0033] When the voltage across L1 is positive, diodes D1 and D6 are turned on, and the other four diodes are turned off due to reverse voltage; when the voltage across L1 is negative, diodes D4, D2, D5, and D3 are turned on, and the other two diodes are turned off due to reverse voltage. The current flow path is as follows: Figure 4 shown.

[0034] Similarly, when the voltage across L2 is positive, diodes D2 and D5 are turned on, and the other four diodes are turned off due to reverse voltage; when the voltage across L2 is negative, diodes D3, D1, D6, and D4 are turned on, and the other two diodes are turned off due to reverse voltage. The current flow path is as follows: Figure 5 shown.

[0035] Compared with the traditional two-phase bridge rectifier circuit, the number of diodes in this two-phase rectifier circuit is reduced from 8 to 6. For each additional phase of the rectifier circuit, only one more bridge arm containing 3 diodes needs to be connected in parallel to the right. When the number of phases increases to N, the number of diodes is also reduced from the traditional 4N to 3N.

[0036] Embodiment 2

[0037] The present invention also proposes a second multi-phase rectifier circuit. When the number of phases increases by one, only two diodes need to be added. N-phase rectification requires a total of 2N+2 diodes. The circuit diagram of Example 2 is shown in FIG. Figure 6 As shown in the figure, it can be seen that the connection method of the inductor is a symmetrical connection completed with the mirror points of the two bridge arms as the corresponding relationship.

[0038] Among them, taking N=3 as an example, the corresponding three-phase rectifier circuit is as follows Figure 7 As shown in the figure, the circuit contains two bridge arms, each of which contains four diodes.

[0039] like Figure 8 As shown in the figure, the current flow path of this three-phase rectifier circuit is analyzed. When the voltage across L1 is positive, diodes D1 and D8 are turned on, and the other six diodes are turned off due to reverse voltage; when the voltage across L1 is negative, diodes D6, D4, D2, D7, D5, and D3 are turned on, and the other two diodes are turned off due to reverse voltage.

[0040] When the voltage across L2 is positive, diodes D3, D1, D8, and D6 are turned on, and the other four diodes are turned off due to reverse voltage; when the voltage across L2 is negative, diodes D4, D2, D7, and D5 are turned on, and the other four diodes are turned off due to reverse voltage. The current flow path is as follows: Fig. 9 shown.

[0041] Embodiment 3

[0042] From the above analysis, we can know that when the voltage across L1 (L3) is forward, 2 diodes are turned on, and when it is reverse, 4 diodes are turned on; and when the voltage across L2 is forward or reverse, the number of diodes turned on is 4. Inconsistent number of diodes turned on will produce different conduction voltage drops, thus affecting the output voltage and efficiency. Therefore, the connection form of the multi-phase rectifier circuit can be changed, such as Fig.10 As shown, the corresponding points of the two bridge arms are connected inductively.

[0043] The circuit shown in the figure above is Figure 6 In comparison, there are only two bridge arms, each of which contains N+1 diodes. i (i=1,…,n) are connected in parallel. Taking N=2 as an example, the corresponding two-phase rectifier circuit is as follows Fig.11 As shown, the two ends of L1 are connected between D1, D3 and D2, D4 respectively, and the two ends of L2 are connected between D3, D5 and D4, D6 respectively.

[0044] Compared with the above rectifier circuit, this rectifier circuit has three diodes conducting regardless of the voltage across L1 in the forward or reverse direction, and the voltage drop generated when the current flows through the diodes is equal. In addition, as the number of phases increases, the number of diodes required also increases from Figure 2 The 3N shown are further reduced to 2N+2.

[0045] In summary, the total number of diodes required by the traditional multi-phase rectifier circuit and the three multi-phase rectifier circuits proposed in the present invention is compared. Fig.12 As shown. Fig.12 As a result, it can be seen that the multi-phase rectifier circuit proposed by the present invention can significantly reduce the number of diodes, thereby reducing the cost of the rectifier and reducing the overall loss. The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

[0046] This patent is not limited to the above-mentioned optimal implementation mode. Anyone can derive other various forms of low-cost multi-phase rectifier circuits with reduced number of diodes under the inspiration of this patent. All equal changes and modifications made according to the scope of the patent application of the present invention should be covered by this patent.

Claims

1. A low-cost multi-phase rectifier circuit with a reduced number of diodes, characterized in that: Assume the number of phases is N, N is greater than or equal to 2, and the total number of diodes used in the multi-phase rectifier circuit is 3N or 2N+2 by connecting inductors across different positions formed by connecting multiple diodes in series on different bridge arms: The total number of diodes used in the multi-phase rectifier circuit is 3N, which is composed of N bridge arms with three diodes connected in series, and each corresponding inductor is connected across the first and second diodes of the adjacent previous bridge arm and the second and third diodes of the next bridge arm; or, The total number of diodes used in the multi-phase rectifier circuit is 2N+2, which is composed of two bridge arms each having N+1 diodes connected in series; each corresponding inductor is connected across the corresponding points or mirror points formed by two bridge arm diodes connected in series.

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