Secondary double-coupling inductor DC-DC converter

Abstract

The invention provides a secondary type double-coupling inductor DC-DC converter, and belongs to the technical field of power electronic converters. On the basis of a secondary cascade boost converter, an input side of the secondary double-coupling inductor DC-DC converter is divided into two branches to shunt input current, and two switching tubes are turned on and off at the same time. Two groups of coupling inductors are introduced to an input side, and a plurality of capacitors and diodes are added to an output side to form a CLC coupling inductor voltage-multiplying unit. The invention has high voltage gain and is suitable for new energy power generation systems such as fuel cells, photovoltaic cells and the like.

Description

Technical Field

[0001] The invention belongs to the field of power electronic converters, in particular to a secondary dual-coupled inductor DC-DC converter. Background Art

[0002] Energy is an important foundation for promoting social development. Against the backdrop of increasing energy shortages and environmental pressures, new power generation technologies (such as wind energy, solar energy, and hydrogen energy) have gained opportunities for rapid development. Among them, fuel cells have gradually become an important clean power generation equipment because they can efficiently and directly convert hydrogen energy into electrical energy. Fuel cells can not only improve energy utilization efficiency, but also have no restrictions on the Carnot cycle during operation and will not cause environmental pollution. However, due to its low voltage and high current output characteristics, there are technical challenges in directly connecting to the inverter system to achieve grid-connected operation. Therefore, it is necessary to use a front-stage power converter with a boost function to increase the voltage to a level that meets the needs of the subsequent inverter system.

[0003] To achieve high voltage gain, boost converters are mainly divided into isolated and non-isolated types. The isolated converter can achieve higher voltage gain by adjusting the turns ratio of the high-frequency transformer, but too large a turns ratio may cause problems such as reduced linearity and increased leakage inductance, which in turn affects efficiency. Non-isolated converters have attracted widespread research interest due to their simple design and lower cost. Traditional boost is the most basic boost converter, which has the characteristics of simple structure and flexible control, but its voltage gain is not high, and the voltage stress on the switching device is also large. Therefore, many scholars have introduced coupled inductor units, secondary cascade structures, capacitor diode units, etc. The secondary cascade boost converter has a higher voltage gain than the boost converter, but in high-power working conditions, excessive input current will cause higher losses and damage to the converter, so it is necessary to improve the input current side into two branches to shunt the input current. The boost converter with coupled inductor unit achieves higher voltage gain by changing the turns ratio of the coupled inductor winding, but due to the influence of leakage inductance, a clamping circuit needs to be introduced to absorb the leakage inductance. The voltage stress of the switch device in the Boost converter based on the capacitor-diode unit is small, but the effective value of the current flowing through the power switch tube is large and the voltage gain is only twice that of the Boost converter. Summary of the invention

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

[0005] The technical solution to achieve the purpose of the present 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 12, coupled inductor winding L 21 , coupled inductor winding L 22 , a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a first power switch tube S1, a second power switch tube S2, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, and a load R; wherein the input source V in The positive pole is connected to the coupled inductor winding L 11 and coupled inductor winding L 21 Anode, input source V in The negative electrode of the first power switch tube S1 is connected to the source electrode of the first power switch tube S1, the negative electrode 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, and the drain electrode of the first power switch tube S1 is connected to the coupling inductor winding L 11 The cathode of the first diode D1 is connected to the positive electrode of the first capacitor C1, the positive electrode of the first diode D1 is connected to the negative electrode of the first capacitor C1 and the source of the second power switch tube S2, and the drain of the second power switch tube S2 is connected to the coupling inductor winding L 21 The drain of the second capacitor C2 is connected to the positive electrode of the second diode D2. The negative electrode of the second diode D2 is connected to the positive electrode of the third capacitor C3 and the positive electrode of the fourth diode D4. The negative electrode of the second capacitor C2 is connected to the anode of the third diode D3 and the positive electrode of the coupled inductor winding L22. The coupled inductor winding L 22 The negative pole is connected to the coupling inductor L 12 The negative pole of the coupled inductor L 12 The positive electrode of the fourth diode D4 is connected to the cathode of the fourth diode D4 and the positive electrode of the fourth capacitor C4, the negative electrode 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 electrode of the fifth capacitor C5 and the other end of the load resistor R, and the on and off of the first power switch tube S1 and the second power switch tube S2 are simultaneously controlled by the control signal Vgs to realize the switching mode change.

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

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

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

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

[0010] Compared with the prior art, the present invention has the following significant advantages:

[0011] (1) By controlling the simultaneous on and off of the two power switches, the on and off conditions of the diodes and the connection mode of the coupling inductor and capacitor in the circuit can be changed, thereby achieving the effect of increasing the voltage gain;

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

[0013] (3) The turns ratios N1 and N2 of the two sets of coupled inductors can be freely selected and are flexible. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The topology diagram of an inductor shunt secondary high gain dual coupled inductor DC boost converter is shown in FIG.

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

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

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

[0018] Figure 5 This is the input current waveform of the inductor shunt secondary high gain dual coupled inductor DC boost converter.

[0019] Figure 6It is the main waveform diagram of the inductor shunt secondary type high gain double coupled inductor DC boost converter; DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0021] like Figure 1 As shown, an inductor shunt secondary high gain dual coupled inductor 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 , a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a first power switch tube S1, a second power switch tube S2, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, and a load R; wherein the input source V in The positive pole is connected to the coupled inductor winding L 11 and coupled inductor winding L 21 Anode, input source V in The negative electrode of the first power switch tube S1 is connected to the source electrode of the first power switch tube S1, the negative electrode 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, and the drain electrode of the first power switch tube S1 is connected to the coupling inductor winding L 11 The cathode of the first diode D1 is connected to the positive electrode of the first capacitor C1, the positive electrode of the first diode D1 is connected to the negative electrode of the first capacitor C1 and the source of the second power switch tube S2, and the drain of the second power switch tube S2 is connected to the coupling inductor winding L 21 The drain of the second capacitor C2 is connected to the positive electrode of the second diode D2. The negative electrode of the second diode D2 is connected to the positive electrode of the third capacitor C3 and the positive electrode of the fourth diode D4. The negative electrode of the second capacitor C2 is connected to the anode of the third diode D3 and the positive electrode of the coupled inductor winding L22. The coupled inductor winding L 22 The negative pole is connected to the coupling inductor L 12 The negative pole of the coupled inductor L 12 The positive electrode of the fourth diode D4 is connected to the cathode of the fourth diode D4 and the positive electrode of the fourth capacitor C4, the negative electrode 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 electrode of the fifth capacitor C5 and the other end of the load resistor R, and the on and off of the first power switch tube S1 and the second power switch tube S2 are simultaneously controlled by the control signal Vgs to realize the switching mode change.

[0022] In a further embodiment, the control signal Vgs of the quadratic dual-coupled inductor DC-DC converter simultaneously controls the 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]. In this stage, the power switches S1 and S2 are turned on at the same time, and the power supply Vin charges the coupled inductor L11. At the same time, the power supply Vin and the capacitor C1 are connected in series to charge the coupled inductor L21. Due to the principle of magnetic induction, the secondary side of the coupled inductor L11 and L22 together with the capacitors C1 and C3 charge the capacitor C2, and mode 1 ends.

[0024] Switching mode 2 corresponds to the time period [t1, t2]. In this stage, the power switches S1 and S2 are turned on at the same time, and the power supply Vin charges the coupled inductor L11. At the same time, the power supply Vin and the 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 inductor L11 and L22 charge the capacitor C2 together with the capacitors C1 and C3. The secondary sides of the coupled inductor L11 and L21 charge the capacitor C4 through the diode D3, and mode 2 ends.

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

[0026] Switching mode 1 and switching mode 2 occur in the same switch on-time and can be regarded as the same mode when calculating the steady-state gain.

[0027] The following relationship can be obtained during the period t0 to t2:

[0028]

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

[0030]

[0031] In one switching cycle, the inductor volt-second balance can be obtained:

[0032]

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

[0034]

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

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

[0037] When the converter operates at [t2, t3], Figure 4 In this stage, the power switches S1 and S2 are turned off at the same time, the coupled inductor L11 charges the capacitor C1 through the diode D1, and the coupled inductor L21 charges the capacitor C3 through the diode D2. At the same time, the coupled inductor L21 and the coupled inductor secondary sides L12 and L22, capacitors C2 and C4 supply power to the load through the diode D5, and 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 the switching mode, reducing the input current.

[0039] like Figure 6 It can be seen that the current ID1 of the diode D1 , the current ID2 of the diode D2 , the current ID3 of the diode D3 , the current ID4 of the diode D4 , and the current ID5 of the diode D5 vary with the waveform of the driving signal Vgs of the 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 , a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a first power switch tube S1, a second power switch tube S2, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, and a load R; wherein the input source V in The positive pole is connected to the coupled inductor winding L 11 and coupled inductor winding L 21 Anode, input source V in The negative electrode of the first power switch tube S1 is connected to the source electrode of the first power switch tube S1, the negative electrode 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, and the drain electrode of the first power switch tube S1 is connected to the coupling inductor winding L 11 The cathode of the first diode D1 is connected to the positive electrode of the first capacitor C1, the positive electrode of the first diode D1 is connected to the negative electrode of the first capacitor C1 and the source of the second power switch tube S2, and the drain of the second power switch tube S2 is connected to the coupling inductor winding L 21 The drain of the second capacitor C2 is connected to the positive electrode of the second diode D2. The negative electrode of the second diode D2 is connected to the positive electrode of the third capacitor C3 and the positive electrode of the fourth diode D4. The negative electrode of the second capacitor C2 is connected to the anode of the third diode D3 and the positive electrode of the coupled inductor winding L22. The coupled inductor winding L 22 The negative pole is connected to the coupling inductor L 12 The negative pole of the coupled inductor L 12 The positive electrode of the fourth diode D4 is connected to the cathode of the fourth diode D4 and the positive electrode of the fourth capacitor C4, the negative electrode 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 electrode of the fifth capacitor C5 and the other end of the load resistor R, and the on and off of the first power switch tube S1 and the second power switch tube S2 are simultaneously controlled by the control signal Vgs to realize the switching mode change.

2. The quadratic dual coupled inductor DC-DC converter according to claim 1, characterized in that: The control signal Vgs simultaneously controls the on and off of the first power switch tube S1 and the second power switch tube S2 to realize 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]. In this stage, the power switches S1 and S2 are turned on at the same time, the power supply Vin charges the coupled inductor L11, the power supply Vin and the capacitor C1 are connected in series to charge the coupled inductor L21, and the secondary sides of the coupled inductor L11 and L22 charge the capacitor C2 together with the capacitors C1 and C3.

4. The quadratic dual coupled inductor DC-DC converter according to claim 2, characterized in that: Switching mode 2 corresponds to the time period [t1, t2]. In this stage, the power switches S1 and S2 are turned on at the same time, and the power supply Vin charges the coupled inductor L11. At the same time, the power supply Vin and the 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 inductor L11 and L22 charge the capacitor C2 together with the capacitors C1 and C3, and the secondary sides of the coupled inductor L11 and L21 charge the capacitor C4 through the diode D3.

5. The quadratic dual coupled inductor DC-DC converter according to claim 2, characterized in that: Switching mode 3 corresponds to the time period [t2, t3]. In this stage, the power switches S1 and S2 are turned off at the same time, the coupled inductor L11 charges the capacitor C1 through the diode D1, and the coupled inductor L21 charges the capacitor C3 through the diode D2. At the same time, the coupled inductor L21 and the coupled inductor secondary sides L12 and L22, capacitors C2 and C4 supply power to the load through the diode D5.

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

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