High-efficiency soft-switching high-boost DC-DC converter based on three-winding coupling inductor

Abstract

The invention discloses a high-efficiency soft-switching high-boost DC-DC converter based on a three-winding coupling inductor. The high-boost DC-DC converter is suitable for the high-boost requirement in a renewable energy system. The converter adopts a three-winding coupling inductor (TWCI), a main switch, an auxiliary switch, a clamping circuit, an output capacitor and other structures, the current change rate of a diode is controlled through leakage inductance of the coupling inductor, reverse recovery loss is effectively restrained, soft switching is achieved, and switching loss and voltage stress are reduced. When the main switch is switched on, input energy is stored in the inductor. During turn-off, energy is transmitted to the output end through the secondary winding and the third winding, leakage inductance energy is recycled through the clamping circuit, and efficiency is improved. The topological structure is small in device number and low in voltage stress, and the problems of efficiency reduction and reliability of a traditional Boost circuit under the high duty ratio are solved. The device has the advantages of high step-up ratio, high efficiency, low electromagnetic interference and the like, is suitable for complex and severe working environments, and has a good industrial application prospect.

Description

Technical Field

[0001] This invention relates to the field of power electronic conversion technology, and in particular to a high-efficiency soft-switching high-boost DC-DC converter based on a three-winding coupled inductor. Background Technology

[0002] In renewable energy systems, such as photovoltaic power generation and fuel cell systems, the output voltage is typically low due to the inherent characteristics of the energy itself. However, grid connection or downstream inverters often require higher DC bus voltages, necessitating the conversion of low-voltage DC to high-voltage DC by high-boost DC-DC converters to meet grid connection or load requirements. Traditional boost converters, such as Boost circuits, while simple in structure and easy to control, face numerous technical bottlenecks in achieving high voltage gain. First, to obtain high gain, a near-limit duty cycle must be used, which not only reduces control accuracy but also exacerbates voltage and current stress on switching devices. Second, a high duty cycle significantly increases the conduction losses of switching transistors and the reverse recovery losses of diodes, resulting in reduced efficiency and severe electromagnetic interference. Furthermore, the high voltage stress on power devices increases the risk of breakdown, affecting system reliability. Simultaneously, the parasitic parameters of traditional converters operating at high frequencies cannot be ignored, further deteriorating gain characteristics and efficiency. Therefore, achieving high voltage gain, low device stress, and high efficiency without relying on extreme duty cycles has become a key technical challenge in renewable energy conversion systems. To address this, researchers have proposed a variety of novel topologies, such as converters based on coupled inductors, voltage multiplier units, and multi-stage combinations, to overcome the performance limitations of traditional solutions and improve the overall efficiency and stability of the system. Summary of the Invention

[0003] The main objective of this invention is to propose a three-coupling inductor boost converter. This design uses fewer power devices and leverages the leakage inductance of the three-winding coupled inductor (TWCI) to control the current drop rate of the diodes, minimizing the reverse recovery problem of other diodes. The technical solution adopted in this invention includes: an input power supply Vin, a three-winding coupled inductor L (including a primary winding Np, a secondary winding Ns, and a tertiary winding Nt), a main switch S1, an auxiliary switch S2, a clamping circuit (including a clamping capacitor C1 and clamping diodes D1 and D2), an output capacitor C0, and a control circuit. The control circuit controls the on and off states of the main switch S1 and the auxiliary switch S2 according to a preset duty cycle.

[0004] During the conduction of the main switch S1, the input power supply Vin charges the coupling inductor L through the primary winding Np, while the voltages on the secondary winding Ns and the tertiary winding Nt are multiplied by a clamping circuit. During the de-energization of the main switch S1, the coupling inductor L releases energy, transferring it to the output capacitor C0 through the secondary winding Ns and the tertiary winding Nt. This invention employs a high-efficiency, high-gain DC-DC boost converter based on a three-coupled inductor. Its advantages lie in the addition of a three-coupled inductor, enabling the inverter to operate under more complex and harsher environmental conditions. It reduces the number of power switching devices, lowers costs in industrial applications, and overcomes the problems of complex topologies and numerous switching devices in common boost circuits, resulting in high voltage stress and switching losses. This three-coupled inductor boost circuit offers advantages in terms of the number of power devices used, total blocking voltage, and switching losses.

[0005] To more clearly illustrate the high-efficiency soft-switching high-boost DC-DC converter with three-winding coupled inductors proposed in this invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0006] Figure 1 The circuit diagram is shown in a specific embodiment of the three-coupled inductor boost circuit provided by the present invention. Figure 2 This is the circuit continuity diagram for the first operating mode of the circuit; Figure 3 This is the circuit continuity diagram for the second operating mode of the circuit; Figure 4 This is the circuit continuity diagram for the third operating mode of the circuit; Figure 5 This is the circuit continuity diagram for the fourth operating mode of the circuit; Detailed Implementation

[0007] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It should be noted that the embodiments described herein are only some embodiments of the present invention, and not all implementations of the present invention. The embodiments are only exemplary.

[0008] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0009] When the circuit is operating in the first working mode: such as Figure 2 As shown, the primary leakage inductance and magnetizing inductance currents increase due to the positive voltage across them, while the secondary and tertiary leakage inductance currents decrease towards zero. The power switch is turned on by the gate signal. The equivalent circuit for this mode is shown below. Figure 2As shown, the primary leakage inductance and magnetizing inductance currents increase due to the positive voltage across them, while the secondary and tertiary leakage inductance currents decrease towards zero. In this mode, Do and D3 are turned on, providing current paths for the secondary winding current. The currents in Do and D3 decrease linearly in this mode. Utilizing the voltage drop across the leakage inductance, the reverse recovery power loss of Do and D3 is minimized.

[0010] When the circuit operates in the second operating mode: as follows: Figure 3 As shown, when the secondary and tertiary winding currents of TWCI are zero, D0 and D3 are turned off, and the currents in these two windings begin to flow in opposite directions. D4 is turned on, providing a current path for the secondary and tertiary winding currents. In this mode, S1 and S2 remain on, capacitors C1 and C3 discharge, and C2 charges.

[0011] When the circuit operates in the third operating mode: For example Figure 4 As shown, S1 and S2 are turned off by the gate signal. Therefore, D1 and D2 are turned on, providing a clamping path for the leakage inductance energy and preventing voltage spikes on the power switches. Instead of using a diode-capacitor clamping circuit for each power switch, two diodes and a capacitor (D1, D2, and C1) are used for both switches to create the optimal clamping path. When the power switches are turned off, the capacitance of the clamping circuit C1 begins to absorb the leakage inductance energy, which is recovered in modes one and two.

[0012] When the circuit operates in the fourth operating mode: such as Figure 5 As shown, at the end of the previous mode, the current in the secondary and tertiary windings reaches zero, and all capacitors except C2 are in a charging state. When the power switch is turned on, diodes D1 and D2 are turned off, and the circuit switches to mode one.

[0013] The above description is merely a preferred embodiment of the present invention, but is not intended to limit the present invention. Various modifications and alterations can be made by those skilled in the art without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A high-efficiency soft-switching high-boost DC-DC converter based on a three-winding coupled inductor, comprising an input power supply Vin, a three-winding coupled inductor L, a main switch S1 and an auxiliary switch S2, a clamping circuit, a clamping capacitor C1 and clamping diodes D1 and D2, an output capacitor C0, and a control circuit, characterized in that, The primary winding N of the three-winding coupled inductor p The secondary winding Np circuit and the tertiary winding Ns circuit are connected to the input power supply Vin. The main switch S1 and the clamping circuit clamping capacitor C1 and clamping diodes D1 and D2 are connected to the main switch S1 and the auxiliary switch S2 to achieve soft switching operation through the control circuit.

2. The high-efficiency soft-switching high-boost DC-DC converter based on a three-winding coupled inductor according to claim 1, characterized in that, The input power supply Vin is a DC power supply. The positive terminal is connected to the inductor Lkp, and the negative terminal is the common ground terminal.

3. The high-efficiency soft-switching high-boost DC-DC converter based on a three-winding coupled inductor according to claim 1, characterized in that, The three-winding coupled inductor includes a clamping circuit (clamping capacitor C1 and clamping diodes D1 and D2). The positive terminal of the clamping capacitor is connected to the drain of switch S2, and the negative terminal is connected to the source of switch S1. The positive terminal of clamping diode D1 is connected to the source of switch S1, and the negative terminal is connected to the source of switch S2. The positive terminal of clamping diode D2 is connected to the drain of switch S1, and the negative terminal is connected to the drain of switch S2.

4. The high-efficiency soft-switching high-boost DC-DC converter based on a three-winding coupled inductor according to claim 1, wherein the three-winding coupled inductor includes a primary winding Np, a secondary winding Ns, and a tertiary winding Nt. The left end of the primary winding Np is connected to the input power supply Vin through inductor Lkp and in parallel with an inductor Lm. The right end is divided into three branches: one branch is connected to the soft switch S1, the second branch is connected to the anode of diode D2, and the third branch is connected to the cathode of capacitor C2 and then to the secondary winding Np. The left side of the secondary winding Ns is connected to the anode of capacitor C2 and then to the drain of switch S1. The right end is connected to inductor Lks and then splits into two branches: one branch is connected to the anode of diode D0, and the other branch is connected to the cathode of D4. The tertiary winding is connected in parallel with diode D5, and the upper side is connected to inductor Lkt and then to the anode of diode D4, and to the cathodes of diodes D3 and D4.

5. The high-efficiency soft-switching high-boost DC-DC converter based on a three-winding coupled inductor according to claim 1, characterized in that, The clamping circuit includes a clamping capacitor C1 and clamping diodes D1 and D2, with the two ends of the clamping capacitor C1 and clamping diodes D1 and D2 respectively connected to two soft switches S1 and S2.

6. The high-efficiency soft-switching high-boost DC-DC converter based on a three-winding coupled inductor according to claim 1, characterized in that, Two switches, S1 and S2, select the IGBT thyristor and control the circuit's operating state through the gate.

7. The high-efficiency soft-switching high-boost DC-DC converter based on a three-winding coupled inductor according to claim 1, characterized in that, The converter uses low-stress diodes and achieves high voltage gain, low voltage stress, and high efficiency through soft switching and clamping circuits.

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