Boost converter based on coupling inductor interleaving

Abstract

The invention provides a boost converter based on coupling inductance interleaving, belongs to the technical field of power electronic direct-current converters, and provides an innovative architecture for solving the problems that a traditional high-gain boost circuit is generally large in component number, high in system cost, low in overall efficiency, remarkable in input current ripple and the like. By introducing a switching voltage clamping technology, the voltage stress and switching loss of a switching device are remarkably reduced; and an interleaving parallel structure is adopted, so that input current ripples in the switching-off process of the MOSFET are effectively inhibited, and the power density of the system is improved at the same time. The converter is widely applicable to various battery power supply systems, fuel cells, photovoltaic power generation and other green energy application occasions, is particularly applicable to technical scenes of low input voltage and high output voltage level, and has the advantages of high step-up ratio, low switching stress, excellent efficiency, simplicity and convenience in control, low cost and the like.

Description

Technical Field

[0001] This invention belongs to the field of power electronic DC-DC converter technology, specifically relating to a boost converter based on coupled inductors. Background Technology

[0002] Against the backdrop of the rapid development of new energy technologies, industries such as photovoltaic power generation, energy storage equipment and electric vehicles have put forward more stringent requirements for DC voltage conversion: not only must it achieve a high gain boost of more than ten times over a wide input voltage range, but it also requires high efficiency (greater than 95%), low overall cost and high operational reliability.

[0003] While traditional boost converters can achieve some voltage boost through multi-stage structures, coupled inductors, or switched capacitors, they generally suffer from inherent problems such as energy loss due to frequent capacitor charging and discharging, excessively high voltage withstand capabilities of switching devices, and large input current ripple. These issues limit overall efficiency and keep costs high, making it difficult to meet the dual performance and economic requirements of new energy applications. Taking a typical photovoltaic application as an example, the output voltage of a single panel is typically between 20–40V, while grid connection requires a voltage boost of over 380V. If a traditional multi-stage boost scheme is used, the system efficiency is generally only 85%–90%, and the cost of capacitor components can exceed 35% of the total cost. How to solve these shortcomings is a key technical problem facing this field. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and propose a boost converter based on coupled inductors. In order to solve the problems of low energy utilization efficiency, high loss and high cost of ordinary high-gain boost converters during operation, this invention reduces costs while having excellent performance.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0006] A boost converter based on interleaved coupled inductors includes a DC voltage source Vin, diodes D0, D1, D2, D3, D4, capacitors C0, C1, C2, C3, C4, coupled inductors L1, L2, MOSFETs Q1, Q2, and load resistor R.

[0007] Wherein, the coupled inductor L1 includes a primary winding N11 and a secondary winding N12, and the coupled inductor L2 includes a primary winding N21 and a secondary winding N22;

[0008] The capacitor C0 serves as the output capacitor, and the voltage across its terminals serves as the output voltage V0 of the boost converter.

[0009] The primary windings of the coupled inductors L1 and L2 are connected to the main circuit, and the corresponding terminals of the secondary windings N12 and N22 are connected to each other, so that the voltages of the two secondary windings remain in the same direction during operation.

[0010] Preferably, the voltage gain M of the boost converter is: Where D is the duty cycle of the MOSFET and n is the turns ratio of the secondary winding N12 to the primary winding N11 of the coupled inductor.

[0011] Preferably, the boost converter has two operating modes within one switching cycle, namely state 1 and state 2; in state 1, MOSFET Q1 is turned on and Q2 is turned off; in state 2, MOSFET Q1 is turned off and Q2 is turned on; MOSFETs Q1 and Q2 are turned on alternately, with a delay of half a cycle.

[0012] Preferably, in the operating mode of state 1:

[0013] DC voltage source Vin charges the primary winding of coupled inductor L1, while the primary winding of coupled inductor L2 discharges.

[0014] The capacitor C1 is charged through the circuit Vin-N21-D2-C1-N12-N22-Q1, and at the same time, this charging circuit clamps the voltage of the MOSFET Q2.

[0015] The capacitor C3 is charged through the circuit Vin-N21-C3-D2-N12-N22-Q1, and voltage clamping is applied to the MOSFET Q2.

[0016] The capacitor C0 is charged through the circuit Vin-N21-C2-D0-C0-C4-N12-N22-Q1, and the load resistor R is powered.

[0017] Preferably, in the two-state operating mode:

[0018] DC voltage source Vin charges the primary winding of coupled inductor L2, while the primary winding of coupled inductor L1 discharges.

[0019] The capacitor C2 is charged through the circuit Vin-N11-N22-N12-C1-D1-C2-Q2, which in turn clamps the voltage of the MOSFET Q1.

[0020] The capacitor C3 is charged through the circuit Vin-N11-N22-N12-C4-D4-C3-Q2, and the voltage of the MOSFET Q1 is clamped.

[0021] Capacitor C0 supplies power to the load resistor R.

[0022] Preferably, the duty cycle D of the MOSFETs Q1 and Q2 is adjustable within the range of (0.55, 1).

[0023] The boost converter based on coupled inductor interleaving described in this invention has the following technical advantages compared with the prior art:

[0024] (1) By using the two main circuits to operate alternately, the input current is continuous and the input current ripple is small, which provides a relatively stable energy to the circuit. The voltage multiplication unit is used to increase the amplification factor of the circuit, thereby adjusting the duty cycle of MOSFETs Q1 and Q2. Even when the boost factor is relatively large, the current ripple can be maintained. At the same time, a voltage clamping circuit is used to clamp the voltage across the switch, reduce the switching loss generated when the switch is opened, suppress the voltage on both sides of the switch, and reduce the switching stress.

[0025] (2) While achieving the same or even higher performance as similar circuits, it requires fewer components, reducing costs. At the same time, the switching clamping circuit results in higher conversion efficiency due to fewer components and lower switching stress. Attached Figure Description

[0026] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0027] Figure 1 This is a schematic diagram of a boost converter based on interleaved coupled inductors, which is an application of the present invention.

[0028] Figure 2 This is the equivalent circuit diagram of the boost converter when MOSFET Q1 is on and Q2 is off in this invention.

[0029] Figure 3 This is the equivalent circuit diagram of the boost converter when MOSFET Q1 is off and Q2 is on in this invention.

[0030] Figure 4 The input waveform of the converter is shown when the input voltage Vin=20V, the output voltage V0=420V, the duty cycle=0.55, and the turns ratio n=1.

[0031] Figure 5 The output waveform of the converter is shown when the input voltage Vin=20V, the output voltage V0=420V, the duty cycle=0.55, and the turns ratio n=1.

[0032] Figure 6The waveform of the voltage VD0 of the output diode D0 is shown when the input voltage Vin=20V, the output voltage V0=420V, the duty cycle=0.55, and the turns ratio n=1. Its peak value is about 160V.

[0033] Figure 7 The waveform of voltage Vs of MOSFETs Q1 and Q2 is shown when the input voltage Vin=20V, the output voltage V0=420V, the duty cycle=0.55, and the turns ratio n=1. The peak value is about 40V.

[0034] Figure 8 The waveforms of the primary winding currents L1 and L2 of the coupled inductor are shown in the embodiment of the present invention when the input voltage Vin=20V, the output voltage V0=420V, the duty cycle=0.55, the turns ratio n=1, and R=500 ohms.

[0035] Figure 9 The waveform of the power supply input current Iin is shown in the embodiment of the present invention when the input voltage Vin=20V, the output voltage V0=420V, the duty cycle=0.55, the turns ratio n=1, and R=500 ohms. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Elements and features described in one embodiment of the present invention can be combined with elements and features shown in one or more other embodiments. It should be noted that, for clarity, representations and descriptions of components and processes unrelated to the present invention and known to those skilled in the art are omitted in the description. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0037] Example 1: Combination Figure 1 As shown, the boost converter based on coupled inductors described in this embodiment includes a DC voltage source Vin, diodes D0 to D4, capacitors C0 to C4, coupled inductors L1 (including its leakage inductance Lk1, magnetizing inductance Lm1, primary winding N11, and secondary winding N12) and L2 (including its leakage inductance Lk2, magnetizing inductance Lm2, primary winding N21, and secondary winding N22), MOSFETs Q1 and Q2, and a load resistor R;

[0038] C0 serves as the output capacitor, and the voltage across it serves as the output voltage V0 of the boost converter. There are two coupled inductors, five capacitors, five diodes, and two MOSFETs.

[0039] Circuit structure as follows Figure 1 As shown, the primary sides of the two coupled inductors are each connected to the main circuit, and the corresponding terminals of the secondary sides are connected. During operation, the voltages of the two secondary sides always remain in the same direction.

[0040] Voltage gain of boost converter Where D is the duty cycle of the MOSFET, and n is the turns ratio of the secondary winding N12 to the primary winding N11 of the coupled inductor (which is also the turns ratio of the secondary winding N22 to the primary winding N21 of the coupled inductor).

[0041] Preferably, this circuit has two operating modes within one switching cycle: state 1 (Q1 on, Q2 off) and state 2 (Q1 off, Q2 on), with MOSFETs Q1 and Q2 conducting alternately for a delay of half a cycle.

[0042] Preferably, such as Figure 2 As shown, in the first operating mode, MOSFET Q1 is turned on and MOSFET Q2 is turned off. At this time, the DC voltage source Vin charges the primary winding of the coupled inductor L1, while the primary winding of the coupled inductor L2 discharges. Due to the principle of magnetic reaction, the secondary windings of the coupled inductors L1 and L2 charge C1 through the circuit Vin-N21-D2-C1-N12-N22-Q1, and this charging circuit clamps the voltage of switch Q2. At the same time, the circuit charges C3 through the circuit Vin-N21-C3-D2-N12-N22-Q1, and this charging circuit clamps the voltage of switch Q2. At the same time, the circuit charges C0 through the circuit Vin-N21-C2-D0-C0-C4-N12-N22-Q1, and supplies power to resistor R.

[0043] Preferably, such as Figure 3 As shown, in the 2-state operating mode, MOSFET Q1 is off and Q2 is on. At this time, the DC voltage source Vin charges the primary winding of the coupled inductor L2, while the primary winding of the coupled inductor L1 discharges, charging C2 through the circuit Vin-L1-N22-N12-D3-C2-Q2. Simultaneously, the primary winding of the coupled inductor L1 discharges, charging C2 through the circuit Vin-N11-N22-N12-C1-D1-C2-Q2. This charging circuit also clamps the voltage of switch Q1. Simultaneously, C3 is charged through the circuit Vin-N11-N22-N12-C4-D4-C3-Q2, also clamping the voltage of switch Q1. At this time, C0 supplies power to the load resistor R.

[0044] Preferably, the duty cycle adjustment range of MOSFETs Q1 and Q2 is (0.55, 1).

[0045] This circuit utilizes the interleaved operation of two main circuits, ensuring continuous input current and minimal input current ripple, thus providing a relatively stable energy supply to the circuit. The use of a voltage multiplication unit increases the circuit's amplification factor, thereby adjusting the duty cycle of MOSFETs Q1 and Q2. Even with a large boost factor, it maintains a small current ripple. Simultaneously, a voltage clamping circuit is employed to clamp the voltage across the switch, reducing switching losses when the switch is open, suppressing voltage fluctuations across the switch, and lowering switching stress. While achieving equivalent or even higher performance than similar circuits, it requires fewer components, reducing costs. Furthermore, the fewer components and lower switching stress, thanks to the switch clamping circuit, result in higher conversion efficiency.

[0046] This embodiment verifies the technical effects of the present invention through simulation. Figure 4 and Figure 5 The converter achieved a stable 420V high voltage output under the conditions of input voltage Vin=20V, duty cycle D=0.55, and turns ratio n=1, verifying the voltage gain capability. Figure 6 and Figure 7 The voltage stress of the output diode D0 and the switching transistors Q1 and Q2 are shown respectively, with peak values ​​of approximately 160V and 40V, respectively, which are far lower than the output voltage. This fully demonstrates the effectiveness of the voltage clamping technology of this invention and significantly reduces the stress and loss of the switching devices. Figure 8 The coupled inductor current waveform shown and Figure 9 As can be seen from the input current Iin waveform shown, the present invention effectively smooths the inductor current and significantly suppresses the input current ripple.

[0047] This invention achieves high gain, low stress, low ripple, and high efficiency simultaneously using only 2 MOSFETs, 2 coupled inductors, 5 capacitors, and 5 diodes, demonstrating its excellent overall performance and cost advantages.

[0048] Finally, it should be noted that although the present invention and its advantages have been described in detail above, it should be understood that various changes, substitutions, and modifications can be made without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the invention is not limited to the specific embodiments of the processes, apparatus, means, methods, and steps described in the specification. Those skilled in the art will readily understand from the disclosure of this invention that existing and future processes, apparatus, means, methods, or steps that perform substantially the same function or obtain substantially the same results as the corresponding embodiments described herein can be used according to the present invention. Therefore, the appended claims are intended to include such processes, apparatus, means, methods, or steps within their scope.

Claims

1. A boost converter based on interleaved coupled inductors, characterized in that, Includes DC voltage source Vin, diodes D0, D1, D2, D3, D4, capacitors C0, C1, C2, C3, C4, coupling inductors L1, L2, MOSFETs Q1, Q2, and load resistor R; Wherein, the coupled inductor L1 includes a primary winding N11 and a secondary winding N12, and the coupled inductor L2 includes a primary winding N21 and a secondary winding N22; The capacitor C0 serves as the output capacitor, and the voltage across its terminals serves as the output voltage V0 of the boost converter. The primary windings of the coupled inductors L1 and L2 are connected to the main circuit, and the corresponding terminals of the secondary windings N12 and N22 are connected to each other, so that the voltages of the two secondary windings remain in the same direction during operation.

2. A boost converter based on interleaved coupled inductors according to claim 1, characterized in that, The voltage gain M of the boost converter is: Where D is the duty cycle of the MOSFET and n is the turns ratio of the secondary winding N12 to the primary winding N11 of the coupled inductor.

3. A boost converter based on interleaved coupled inductors according to claim 2, characterized in that, The boost converter has two operating modes within one switching cycle, namely state 1 and state 2. In state 1, MOSFET Q1 is turned on and Q2 is turned off. In state 2, MOSFET Q1 is turned off and Q2 is turned on. MOSFETs Q1 and Q2 are turned on alternately, with a delay of half a cycle.

4. A boost converter based on interleaved coupled inductors according to claim 3, characterized in that, Under the operating mode of state 1: DC voltage source Vin charges the primary winding of coupled inductor L1, while the primary winding of coupled inductor L2 discharges. The capacitor C1 is charged through the circuit Vin-N21-D2-C1-N12-N22-Q1, and at the same time, this charging circuit clamps the voltage of the MOSFET Q2. The capacitor C3 is charged through the circuit Vin-N21-C3-D2-N12-N22-Q1, and voltage clamping is applied to the MOSFET Q2. The capacitor C0 is charged through the circuit Vin-N21-C2-D0-C0-C4-N12-N22-Q1, and the load resistor R is powered.

5. A boost converter based on interleaved coupled inductors according to claim 3, characterized in that, Under the two-state operating mode: DC voltage source Vin charges the primary winding of coupled inductor L2, while the primary winding of coupled inductor L1 discharges. The capacitor C2 is charged through the circuit Vin-N11-N22-N12-C1-D1-C2-Q2, which in turn clamps the voltage of the MOSFET Q1. The capacitor C3 is charged through the circuit Vin-N11-N22-N12-C4-D4-C3-Q2, and the voltage of the MOSFET Q1 is clamped. Capacitor C0 supplies power to the load resistor R.

6. A boost converter based on interleaved coupled inductors according to claim 2, characterized in that, The duty cycle D of the MOSFETs Q1 and Q2 can be adjusted within the range of (0.55, 1).

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