Quadratic dual-coupled inductor dc-dc converter

Abstract

This invention proposes a quadratic dual-coupled inductor DC-DC converter, belonging to the technical field of power electronic converters. Based on a quadratic cascaded boost converter, the quadratic dual-coupled inductor DC-DC converter splits the input current into two branches on the input side, and both switching transistors are simultaneously turned on and off. Two sets of coupled inductors are introduced on the input side, and several capacitors and diodes are added on the output side to form a CLC coupled inductor voltage multiplier unit. This invention has high voltage gain and is suitable for new energy power generation systems such as fuel cells and photovoltaic cells.

Description

Technical Field

[0001] This invention belongs to the field of power electronic converters, specifically a quadratic dual-coupled inductor DC-DC converter. Background Technology

[0002] Energy is a crucial foundation for social development. Against the backdrop of increasing energy shortages and environmental pressures, new power generation technologies (such as wind, solar, and hydrogen energy) have gained a rapid development opportunity. Among them, fuel cells, due to their ability to efficiently and directly convert hydrogen into electricity, are gradually becoming important clean power generation devices. Fuel cells not only improve energy utilization efficiency but also operate without the limitations of the Carnot cycle and do not produce environmental pollution. However, due to their low-voltage, high-current output characteristics, direct connection to an inverter system for grid-connected operation presents technical challenges. Therefore, a front-end power converter with boost function is needed to increase the voltage to a level that meets the requirements of the subsequent inverter system.

[0003] To achieve high voltage gain, boost converters are mainly divided into isolated and non-isolated types. Isolated converters can achieve higher voltage gain by adjusting the turns ratio of the high-frequency transformer, but an excessively large turns ratio can lead to reduced linearity and increased leakage inductance, thus affecting efficiency. Non-isolated converters, due to their simpler design and lower cost, have attracted widespread research interest. The traditional boost converter is the most basic type, characterized by its simple structure and flexible control, but its voltage gain is not high, and the voltage stress on the switching devices is also relatively large. Therefore, many researchers have introduced coupled inductor units, secondary cascade structures, and capacitor-diode units. Secondary cascaded boost converters have higher voltage gain than traditional boost converters, but in high-power applications, excessive input current can lead to higher losses and damage to the converter. Therefore, it is necessary to modify the input current side to have two branches to shunt the input current. Boost converters with coupled inductor units achieve higher voltage gain by changing the turns ratio of the coupled inductor winding, but due to the influence of leakage inductance, clamping circuits are needed to absorb the leakage inductance. In a Boost converter based on a capacitor-diode unit, the voltage stress on the switching devices is relatively small, but the effective value of the current flowing through the power switch is large and the voltage gain is only twice that of the Boost converter. Summary of the Invention

[0004] The purpose of this invention is to provide a quadratic dual-coupled inductor high-gain DC-DC converter.

[0005] The technical solution to achieve the objective of this invention is: a quadratic dual-coupled inductor DC-DC converter, including an input source V in Coupled inductor winding L 11 Coupled inductor winding L 12Coupled inductor winding L 21 Coupled inductor winding L 22 The following components are used: first diode D1, second diode D2, third diode D3, fourth diode D4, fifth diode D5, first power switch S1, second power switch S2, first capacitor C1, second capacitor C2, third capacitor C3, fourth capacitor C4, fifth capacitor C5, and load R; where the input source V... in The positive terminal is connected to the coupled inductor winding L 11 and coupling inductor winding L 21 The anode, input source V in The negative terminal is connected to the source of the first power switch S1, the negative terminal of the first diode D1, the cathode of the third capacitor C3, the cathode of the fifth capacitor C5, and one end of the load resistor R. The drain of the first power switch S1 is connected to the coupling inductor winding L. 11 The cathode of the first diode is connected to the positive terminal of the first capacitor C1, the positive terminal of the first diode D1 is connected to the negative terminal of the first capacitor C1, and the source of the second power switch S2 is connected to the drain of the second power switch S2. 21 The drain of the first capacitor, the positive terminal of the second capacitor C2, and the positive terminal of the second diode D2 are connected. The negative terminal of the second diode D2 is connected to the positive terminal of the third capacitor C3 and the positive terminal of the fourth diode D4. The negative terminal of the second capacitor C2 is connected to the anode of the third diode D3 and the positive terminal of the coupling inductor winding L22. 22 The negative terminal is connected to the coupling inductor L 12 The negative terminal, coupled inductor L 12 The positive terminal of the first power switch S1 and the second power switch S2 are connected to the cathode of the fourth diode D4 and the positive terminal of the fourth capacitor C4. The negative terminal of the fourth capacitor C4 is connected to the cathode of the third diode D3 and the anode of the fifth diode D5. The cathode of the fifth diode D5 is connected to the positive terminal of the fifth capacitor C5 and the other end of the load resistor R. The switching mode change is achieved by simultaneously controlling the on and off of the first power switch S1 and the second power switch S2 through the control signal Vgs.

[0006] Preferably, the control signal Vgs simultaneously controls the on / off states of the first power switch S1 and the second power switch S2 to achieve three switching modes.

[0007] Preferably, the switching mode 1 corresponds to the time period [t0, t1]. During this period, power switches S1 and S2 are turned on simultaneously, power supply Vin charges coupling inductor L11, power supply Vin and capacitor C1 are connected in series to charge coupling inductor L21, and the secondary sides of coupling inductors L11 and L22, together with capacitors C1 and C3, charge capacitor C2.

[0008] Preferably, the switching mode 2 corresponds to the time period [t1, t2]. During this stage, power switches S1 and S2 are simultaneously turned on, and power supply Vin charges the coupling inductor L11. At the same time, power supply Vin and capacitor C1 are connected in series to charge the coupling inductor L21. Due to the principle of magnetic induction, the secondary sides of the coupling inductors L11 and L22, together with capacitors C1 and C3, charge capacitor C2. The secondary sides of the coupling inductors L11 and L21 charge capacitor C4 through diode D3.

[0009] Preferably, the switching mode 3 corresponds to the time period [t2, t3]. During this period, the power switches S1 and S2 are turned off simultaneously. The coupling inductor L11 charges the capacitor C1 through the diode D1, and the coupling inductor L21 charges the capacitor C3 through the diode D2. At the same time, the coupling inductor L21 and the secondary sides of the coupling inductors L12 and L22, as well as the capacitors C2 and C4, supply power to the load through the diode D5.

[0010] Compared with the prior art, the significant advantages of this invention are:

[0011] (1) By controlling the simultaneous conduction and cutoff of two power switching transistors, the on / off state of the diodes and the connection method of the coupling inductor and capacitor in the circuit can be changed, thereby achieving the effect of increasing voltage gain.

[0012] (2) While maintaining the advantages of the quadratic converter, the inductor current is effectively reduced by shunting the current through two branches;

[0013] (3) The turns ratio of the two sets of coupled inductors, N1 and N2, can be freely selected, allowing for flexibility. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a high-gain dual-coupled inductor DC-DC boost converter topology with inductor shunt secondary type.

[0015] Figure 2 This is an equivalent schematic diagram of the switching mode 1 of an inductor-shunt secondary high-gain dual-coupled inductor DC-DC boost converter.

[0016] Figure 3 This is an equivalent schematic diagram of the switching mode 2 of an inductor-shunt secondary high-gain dual-coupled inductor DC-DC boost converter.

[0017] Figure 4 This is an equivalent schematic diagram of the switching mode 3 of an inductor-shunt secondary high-gain dual-coupled inductor DC-DC boost converter.

[0018] Figure 5 The input current waveform is shown for an inductor-shunt secondary high-gain dual-coupled inductor DC-DC boost converter.

[0019] Figure 6The main waveforms of an inductor-shunt secondary high-gain dual-coupled inductor DC-DC boost converter are shown below. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0021] like Figure 1 As shown, an inductor-shunt quadratic high-gain dual-coupled inductor DC-DC boost converter includes an input source V. in Coupled inductor winding L 11 Coupled inductor winding L 12 Coupled inductor winding L 21 Coupled inductor winding L 22 The following components are used: first diode D1, second diode D2, third diode D3, fourth diode D4, fifth diode D5, first power switch S1, second power switch S2, first capacitor C1, second capacitor C2, third capacitor C3, fourth capacitor C4, fifth capacitor C5, and load R; where the input source V... in The positive terminal is connected to the coupled inductor winding L 11 and coupling inductor winding L 21 The anode, input source V in The negative terminal is connected to the source of the first power switch S1, the negative terminal of the first diode D1, the cathode of the third capacitor C3, the cathode of the fifth capacitor C5, and one end of the load resistor R. The drain of the first power switch S1 is connected to the coupling inductor winding L. 11 The cathode of the first diode is connected to the positive terminal of the first capacitor C1, the positive terminal of the first diode D1 is connected to the negative terminal of the first capacitor C1, and the source of the second power switch S2 is connected to the drain of the second power switch S2. 21 The drain of the first capacitor, the positive terminal of the second capacitor C2, and the positive terminal of the second diode D2 are connected. The negative terminal of the second diode D2 is connected to the positive terminal of the third capacitor C3 and the positive terminal of the fourth diode D4. The negative terminal of the second capacitor C2 is connected to the anode of the third diode D3 and the positive terminal of the coupling inductor winding L22. 22 The negative terminal is connected to the coupling inductor L 12 The negative terminal, coupled inductor L 12 The positive terminal of the first power switch S1 and the second power switch S2 are connected to the cathode of the fourth diode D4 and the positive terminal of the fourth capacitor C4. The negative terminal of the fourth capacitor C4 is connected to the cathode of the third diode D3 and the anode of the fifth diode D5. The cathode of the fifth diode D5 is connected to the positive terminal of the fifth capacitor C5 and the other end of the load resistor R. The switching mode change is achieved by simultaneously controlling the on and off of the first power switch S1 and the second power switch S2 through the control signal Vgs.

[0022] In a further embodiment, the control signal Vgs of the quadratic dual-coupled inductor DC-DC converter simultaneously controls the switching on and off of power switches S1 and S2; the entire control process is divided into three switching modes, namely switching mode 1, switching mode 2, and switching mode 3.

[0023] Switching mode 1 corresponds to the time period [t0, t1]. During this stage, power switches S1 and S2 are simultaneously turned on, and power supply Vin charges coupled inductor L11. At the same time, power supply Vin and capacitor C1 are connected in series to charge coupled inductor L21. Due to the principle of magnetic induction, the secondary sides of coupled inductors L11 and L22, together with capacitors C1 and C3, charge capacitor C2, and mode 1 ends.

[0024] The switching mode 2 corresponds to the time period [t1, t2]. During this stage, power switches S1 and S2 are simultaneously turned on, and power supply Vin charges the coupled inductor L11. At the same time, power supply Vin and capacitor C1 are connected in series to charge the coupled inductor L21. Due to the principle of magnetic induction, the secondary sides of the coupled inductors L11 and L22, together with capacitors C1 and C3, charge capacitor C2. The secondary sides of the coupled inductors L11 and L21 charge capacitor C4 through diode D3. Mode 2 ends.

[0025] Switching mode 3 corresponds to the time period [t2, t3]. During this stage, power switches S1 and S2 are turned off simultaneously. Coupling inductor L11 charges capacitor C1 through diode D1, and coupling inductor L21 charges capacitor C3 through diode D2. At the same time, coupling inductor L21, along with the secondary sides of coupling inductors L12 and L22, and capacitors C2 and C4, supply power to the load through diode D5. Mode 3 ends.

[0026] Switching mode 1 and switching mode 2 occur within the same switching time, and can be considered as the same mode when calculating steady-state gain.

[0027] The following relationship can be obtained for the t0 to t2 stage:

[0028]

[0029] The following relationship can be obtained from t2 to t3:

[0030]

[0031] In one switching cycle, the inductor volt-second balance yields:

[0032]

[0033] Combining equations (1) and (3), the input-output voltage relationship is obtained as follows:

[0034]

[0035] When the converter operates in the range [t0, t1], as follows Figure 2 As shown. In this stage, power switches S1 and S2 are simultaneously turned on, and power supply Vin charges coupled inductor L11. At the same time, power supply Vin and capacitor C1 are connected in series to charge coupled inductor L21. Due to the principle of magnetic induction, the secondary sides of coupled inductors L11 and L22, together with capacitors C1 and C3, charge capacitor C2, and mode 1 ends.

[0036] When the converter operates in the range [t1, t2], as follows Figure 3 As shown. In this stage, power switches S1 and S2 are simultaneously turned on, and power supply Vin charges coupled inductor L11. At the same time, power supply Vin and capacitor C1 are connected in series to charge coupled inductor L21. Due to the principle of magnetic induction, the secondary sides of coupled inductors L11 and L22, together with capacitors C1 and C3, charge capacitor C2. The secondary sides of coupled inductors L11 and L21 charge capacitor C4 through diode D3, and mode 2 ends.

[0037] When the converter operates in the range [t2, t3], as follows Figure 4 As shown. In this stage, power switches S1 and S2 are turned off simultaneously. Coupling inductor L11 charges capacitor C1 through diode D1, and coupling inductor L21 charges capacitor C3 through diode D2. At the same time, coupling inductor L21, along with the secondary sides of coupling inductors L12 and L22, and capacitors C2 and C4, supply power to the load through diode D5. Mode 3 ends.

[0038] like Figure 5 It can be seen that the input current is divided into two parts, which rise and fall simultaneously with the change of switching mode, thus reducing the input current.

[0039] like Figure 6 It can be seen that the currents ID1 of diode D1, ID2 of diode D2, ID3 of diode D3, ID4 of diode D4, and ID5 of diode D5 change with the waveform of the drive signal Vgs of power switches S1 and S2.

Claims

1. A quadratic dual-coupled inductor DC-DC converter, characterized in that, Including input source V in Coupled inductor winding L 11 Coupled inductor winding L 12 Coupled inductor winding L 21 Coupled inductor winding L 22 The following components are used: first diode D1, second diode D2, third diode D3, fourth diode D4, fifth diode D5, first power switch S1, second power switch S2, first capacitor C1, second capacitor C2, third capacitor C3, fourth capacitor C4, fifth capacitor C5, and load R; where the input source V... in The positive terminal is connected to the coupled inductor winding L 11 and coupling inductor winding L 21 The same name end, input source V in The negative terminal is connected to the source of the first power switch S1, the negative terminal of the first diode D1, the cathode of the third capacitor C3, the cathode of the fifth capacitor C5, and one end of the load resistor R. The drain of the first power switch S1 is connected to the coupling inductor winding L. 11 The opposite terminal of the first diode D1 is connected to the positive terminal of the first capacitor C1, the positive terminal of the first diode D1 is connected to the negative terminal of the first capacitor C1, and the source of the second power switch S2 is connected to the drain of the second power switch S2. 21 The opposite terminal of the first capacitor, the positive terminal of the second capacitor C2, and the positive terminal of the second diode D2 are connected. The negative terminal of the second diode D2 is connected to the positive terminal of the third capacitor C3 and the positive terminal of the fourth diode D4. The negative terminal of the second capacitor C2 is connected to the anode of the third diode D3 and the same-name terminal of the coupling inductor winding L22. 22 Heterogeneous termination coupling inductor L 12 The opposite terminal, coupled inductor L 12 The same terminal is connected to the cathode of the fourth diode D4 and the positive terminal of the fourth capacitor C4. The negative terminal of the fourth capacitor C4 is connected to the cathode of the third diode D3 and the anode of the fifth diode D5. The cathode of the fifth diode D5 is connected to the positive terminal of the fifth capacitor C5 and the other end of the load resistor R. The switching mode change is achieved by simultaneously controlling the on and off of the first power switch S1 and the second power switch S2 through the control signal Vgs. The coupling inductor winding L 11 With coupling inductor winding L 12 For the primary winding, the coupled inductor winding L 21 Coupled inductor winding L 22 For secondary windings, coupled inductor winding L 11 With coupling inductor winding L 22 Mutual coupling, coupled inductor winding L 12 With coupling inductor winding L 21 Mutual coupling.

2. The quadratic dual-coupled inductor DC-DC converter according to claim 1, characterized in that, The control signal Vgs simultaneously controls the on / off state of the first power switch S1 and the second power switch S2 to achieve three switching modes.

3. The quadratic dual-coupled inductor DC-DC converter according to claim 2, characterized in that, Switching mode 1 corresponds to the time period [t0, t1]. During this stage, power switches S1 and S2 are turned on simultaneously. Power supply Vin charges the coupling inductor L11. Power supply Vin and capacitor C1 are connected in series to charge the coupling inductor L21. The secondary sides of the coupling inductor L12 and L22, together with capacitors C1 and C3, charge capacitor C2.

4. The quadratic dual-coupled inductor DC-DC converter according to claim 2, characterized in that, During the time period [t1, t2] corresponding to switching mode 2, power switches S1 and S2 are turned on simultaneously, and power supply Vin charges coupled inductor L11. At the same time, power supply Vin and capacitor C1 are connected in series to charge coupled inductor L21. Due to the principle of magnetic induction, the secondary sides of coupled inductors L12 and L22, together with capacitors C1 and C3, charge capacitor C2. The secondary sides of coupled inductors L12 and L21 charge capacitor C4 through diode D3.

5. The quadratic dual-coupled inductor DC-DC converter according to claim 2, characterized in that, During the time period [t2, t3] corresponding to switching mode 3, power switches S1 and S2 are turned off simultaneously. Coupling inductor L11 charges capacitor C1 through diode D1, and coupling inductor L21 charges capacitor C3 through diode D2. At the same time, coupling inductor L21 and the secondary sides of coupling inductors L12 and L22, and capacitors C2 and C4 supply power to the load through diode D5.

6. The quadratic dual-coupled inductor DC-DC converter according to claim 2, characterized in that, The specific gains for the three switching modes are as follows: In the formula, D is the duty cycle of power switches S1 and S2, with an operating range of (0,1). The turns ratios of the two coupled inductors are n1 = N2:N1 and n2 = N4:N3, where N1 and N2 are the windings of coupled inductors L11 and L12, and N3 and N4 are the windings of coupled inductors L21 and L22.

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