Dual-switch high-voltage step-up DC converter with low switching voltage stress

Abstract

The present invention relates to a dual-switch high-voltage boost DC converter with low switching voltage stress. The converter comprises an input DC voltage Vi, inductors L1-L3, capacitors C1-C5, capacitor Co, diodes D1-D6, a diode Do, MOSFET switches S1-S2, and a load Ro. The positive electrode of the input DC voltage Vi is connected to one end of the inductor L1, the anode of the diode D3, and one end of the capacitor C1 and capacitor C4, respectively. The negative electrode of the input DC voltage Vi is connected to the other end of the capacitor C3, the source of the MOSFET switch S1, and the cathode of the diode D6, respectively. The anode of the diode D6 is connected to the other end of the capacitor C5, the negative electrode of the capacitor Co, and the negative electrode of the load Ro, respectively. The cathode of the diode Do is connected to the positive electrode of the capacitor Co and the positive electrode of the load Ro, respectively. The present invention realizes the high voltage gain function of the boost DC converter, reduces the voltage stress of the switches, and improves the cost-effectiveness of the DC converter circuit. The converter can be widely used in the field of DC conversion.

Description

Technical Field

[0001] The present invention belongs to the technical field of direct current converters, and in particular to a dual-switch high-boost direct current converter with low switching voltage stress. Background Art

[0002] Boost DC converters, a core technology in power electronics, are becoming increasingly popular in many industrial fields. DC converters are categorized into isolated and non-isolated types. Isolated DC converters are easier to boost than non-isolated ones. However, isolated DC converters suffer from significant switching surge energy losses, and are relatively bulky and heavy, increasing their cost. Consequently, non-isolated DC converters are attracting increasing attention from researchers.

[0003] Theoretically, using extreme duty cycles can achieve high voltage gain. However, in practice, due to the influence of the equivalent resistance of inductors and capacitors and the parasitic parameters of switching devices, DC conversion efficiency drops sharply after the duty cycle reaches a certain value. Even at the extreme duty cycle of 0.9, traditional boost-type DC converters struggle to achieve high voltage gain. Furthermore, in traditional boost-type DC converters, the switch voltage stress is equal to the output voltage. This necessitates the use of switching devices with high withstand voltage and high on-state resistance in high-voltage applications, which inevitably leads to large on-state losses. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a dual-switch high-voltage boost DC converter with low switching voltage stress, thereby solving the problem that the existing boost DC converter cannot meet the high gain requirements and low switching voltage stress in industrial applications.

[0005] The present invention solves the technical problem by adopting the following technical solutions:

[0006] A dual-switch high-step-up DC converter with low switching voltage stress includes an input DC voltage Vi, inductors L1 to L3, capacitors C1 to C5, capacitor Co, diodes D1 to D7, MOSFET switch tubes S1 to S2, and a load Ro; the positive electrode of the input DC voltage Vi is respectively connected to one end of the inductor L1, the anode of the diode D3, and one end of the capacitor C1 and the capacitor C4; the other end of the inductor L1 is respectively connected to the anodes of the diode D1 and the diode D2; the cathode of the diode D1 is connected to the other end of the capacitor C1 and one end of the inductor L2; the other end of the inductor L2 is respectively connected to one end of the capacitor C2, the cathode of the diode D2, the drain of the MOSFET switch tube S1, and the source of S2; the cathode of the diode D3 is respectively connected to the other end of the capacitor C2 and the diode D2; The anode of the diode D4 is connected to the anode of the capacitor C3, the cathode of the diode D4 is connected to one end of the capacitor C3 and one end of the inductor L3 respectively. The other end of the inductor L3 is connected to the drain of the MOSFET switch tube S2, one end of the capacitor C5 and the anode of the diode D5 respectively. The cathode of the diode D5 is connected to the other end of the capacitor C4 and the anode of the output diode Do respectively. The negative electrode of the input DC voltage Vi is connected to the other end of the capacitor C3, the source of the MOSFET switch tube S1 and the cathode of the diode D6 respectively. The anode of the diode D6 is connected to the other end of the capacitor C5, the negative electrode of the capacitor Co, the negative electrode of the load Ro and the negative electrode of the output DC voltage Vo respectively; the cathode of the diode Do is connected to the positive electrode of the capacitor Co, the positive electrode of the load Ro and the positive electrode of the output DC voltage Vo respectively.

[0007] Furthermore, when the duty cycle of the dual-switch high-step-up DC converter with low switching voltage stress is 0.5, the output DC voltage Vo is 20 times the input DC voltage Vi, the voltage stress of the MOSFET switch tube S1 is 1 / 5 of the output DC voltage Vo, and the voltage stress of the MOSFET switch tube S2 is 3 / 10 of the output DC voltage Vo.

[0008] The advantages and positive effects of the present invention are:

[0009] 1. The dual-switch high-voltage boost DC converter of the present invention charges and discharges the input DC voltage Vi through capacitors and inductors to achieve high voltage gain, solving the problem that existing boost DC converters cannot meet the high gain requirements and low switch voltage stress in industrial applications.

[0010] 2. The dual-switch high-voltage boost DC converter of the present invention reduces the voltage stress of the MOSFET switch tube and improves the efficiency of the DC converter circuit.

[0011] 3. The present invention has a reasonable design, realizes the high voltage gain function of the boost DC converter, meets the high gain requirement in industrial applications, reduces the voltage stress of the switch, improves the cost performance of the DC converter circuit, and can be widely used in the field of DC conversion. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a circuit diagram of the present invention;

[0013] Figure 2 It is a diagram of the driving signal Vgs of the MOSFET switch tube S1 and the MOSFET switch tube S2. DETAILED DESCRIPTION

[0014] The embodiments of the present invention are further described below in conjunction with the accompanying drawings:

[0015] A dual-switch high-voltage boost DC converter with low switching voltage stress, such as Figure 1 As shown, it includes input DC voltage Vi, inductors (L1, L2, L3), capacitors (C1, C2, C3, C4, C5, Co), diodes (D1, D2, D3, D4, D5, D6, Do), MOSFET switches (S1 and S2) and load Ro. The following is a detailed description of the circuit structure of the dual-switch high-voltage boost DC converter:

[0016] The positive electrode of the input DC voltage Vi is respectively connected to one end of the inductor L1, the anode of the diode D3 and one end of the capacitors C1 and C4; the other end of the inductor L1 is respectively connected to the anodes of the diodes D1 and D2; the cathode of the diode D1 is connected to the other end of the capacitor C1 and one end of the inductor L2; the other end of the inductor L2 is respectively connected to one end of the capacitor C2, the cathode of the diode D2, the drain of the MOSFET switch tube S1 and the source of S2; the cathode of the diode D3 is respectively connected to the other end of the capacitor C2 and the anode of the diode D4; the cathode of the diode D4 is respectively connected to one end of the capacitor C3 and one end of the inductor L3; the other end of the inductor L3 is respectively connected to the MOSFET switch tube S1 and the source of S2. The drain of the ET switch tube S2, one end of the capacitor C5 and the anode of the diode D5 are connected; the cathode of the diode D5 is respectively connected to the other end of the capacitor C4 and the anode of the output diode Do; the negative electrode of the input DC voltage Vi is respectively connected to the other end of the capacitor C3, the source of the MOSFET switch tube S1 and the cathode of the diode D6; the anode of the diode D6 is respectively connected to the other end of the capacitor C5, the negative electrode of the capacitor Co (the negative electrode of the output DC voltage Vo) and the negative electrode of the load Ro (the negative electrode of the output DC voltage Vo); the cathode of the diode Do is respectively connected to the positive electrode of the capacitor Co (the positive electrode of the output DC voltage Vo) and the positive electrode of the load Ro (the positive electrode of the output DC voltage Vo).

[0017] Figure 2 A diagram of the drive signal Vgs for MOSFET switches S1 and S2 is shown. In this embodiment, MOSFET switches S1 and S2 are turned on or off simultaneously. A cycle Ts is divided into a switch-on period Ton and a switch-off period Toff. The switch-on period Ton is t0-t1, expressed as DTs using a duty cycle D. The switch-off period Toff is t1-t2, expressed as (1-D)Ts using a duty cycle D.

[0018] The working principle of the present invention is:

[0019] When the MOSFET switch tube S1 and MOSFET switch tube S2 are in Figure 2 During the Ton time period shown, the input DC voltage Vi charges the inductor L1 via the diode D2 and the MOSFET switch tube S1, and charges the capacitor C2 via the MOSFET switch tube S1 and the diode D3; the capacitor C3 charges the inductor L3 via the MOSFET switch tubes S1 and S2; the input DC voltage Vi, capacitors C4 and C5 supply power to the capacitor Co and the load Ro via the diode Do and the MOSFET switch tubes S1 and S2; the input DC voltage Vi and capacitor C1 charge the inductor L2 via the MOSFET switch tube S1.

[0020] When the MOSFET switch tube S1 and the MOSFET switch tube S2 are in the Figure 2 During the Toff time period shown, the input DC voltage Vi, the inductor L1, the inductor L2, and the capacitor C2 charge the capacitor C3 via the diode D1 and the diode D4. The input DC voltage Vi, the inductor L1, the inductor L2, the inductor L3, and the capacitor C2 charge the capacitor C4 via the diode D1, the diode D4, and the diode D6. The inductor L1, the inductor L2, the inductor L3, and the capacitor C2 charge the capacitor C5 via the diode D1, the diode D4, and the diode D5. The inductor L1 charges the capacitor C1 via the diode D1. The capacitor Co supplies power to the load Ro.

[0021] Theoretical derivation shows that when the duty cycle of the dual-switch high-step-up DC converter with low switching voltage stress proposed in the present invention is D=0.5, the output DC voltage Vo is 20 times the input DC voltage Vi, the voltage stress of the MOSFET switch tube S1 is only 1 / 5 of the output DC voltage Vo, and the voltage stress of the MOSFET switch tube S2 is only 3 / 10 of the output DC voltage Vo, meeting the requirements of high gain and low switching voltage stress in industrial applications.

[0022] It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive. Therefore, the present invention includes but is not limited to the embodiments described in the specific embodiments. Any other embodiments derived by those skilled in the art based on the technical solutions of the present invention also fall within the scope of protection of the present invention.

Claims

1. A dual-switch high-voltage step-up DC converter with low switching voltage stress, characterized by: The invention comprises an input DC voltage Vi, an inductor L1 to L3, a capacitor C1 to C5, a capacitor Co, a diode D1 to D6, a diode Do, a MOSFET switch tube S1 to S2 and a load Ro; the positive electrode of the input DC voltage Vi is respectively connected to one end of the inductor L1, the anode of the diode D3 and one end of the capacitor C1 and the capacitor C4, the other end of the inductor L1 is respectively connected to the anodes of the diode D1 and the diode D2, the cathode of the diode D1 is connected to the other end of the capacitor C1 and one end of the inductor L2, the other end of the inductor L2 is respectively connected to one end of the capacitor C2, the cathode of the diode D2, the drain of the MOSFET switch tube S1 and the source of S2, and the cathode of the diode D3 is respectively connected to the other end of the capacitor C2 and the anode of the diode D4 The cathode of the diode D4 is respectively connected to one end of the capacitor C3 and one end of the inductor L3, the other end of the inductor L3 is respectively connected to the drain of the MOSFET switch tube S2, one end of the capacitor C5 and the anode of the diode D5, the cathode of the diode D5 is respectively connected to the other end of the capacitor C4 and the anode of the output diode Do, the negative electrode of the input DC voltage Vi is respectively connected to the other end of the capacitor C3, the source of the MOSFET switch tube S1 and the cathode of the diode D6, the anode of the diode D6 is respectively connected to the other end of the capacitor C5, the negative electrode of the capacitor Co, the negative electrode of the load Ro and the negative electrode of the output DC voltage Vo; the cathode of the diode Do is respectively connected to the positive electrode of the capacitor Co, the positive electrode of the load Ro and the positive electrode of the output DC voltage Vo.

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