High-gain DCDC boost converter under DCM

Abstract

The utility model discloses a high-gain DCDC boost converter under DCM. The high-gain DCDC boost converter comprises an input stage unit, two inductance boost units and an output voltage stabilization unit. The input stage unit is connected with the two inductance boosting units, and the two inductance boosting units are connected with the output voltage stabilizing unit; the circuit has two working states, namely a CCM working state and a DCM working state, and has a better gain effect in the DCM state; in the DCM state, three small states are provided, namely, the input inductor is in the DCM state and the boost inductor is in the CCM state; the input inductor is in a CCM state and the boost inductor is in a DCM state; the input inductor and the boost inductor are in a DCM state at the same time. When operating in DCM mode, the converter has a greater voltage gain ratio than when operating in CCM. The circuit is characterized in that the used inductor is less, and the DCM converter is smaller and lighter. Therefore, the goals of high gain, low element voltage stress, low circuit loss and smaller and cheaper converter are achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of power electronics, can be applied to a DCM (discontinuous conduction mode) boost circuit for photovoltaic power generation and energy storage, and specifically relates to a high-gain DCDC boost converter under DCM. Background Art

[0002] Due to the growth of renewable energy systems in recent years, power electronic converters have become more common. With the reduction in the cost of photovoltaic systems and the substantial access to energy storage systems, the design requirements for high-gain DCDC boost converters have gradually increased. However, there are some problems with high-gain boost circuits. High-gain boost circuits may cause large voltage stress on devices such as diode switches, resulting in problems such as large circuit size and high cost. Therefore, in order to meet such requirements, it is necessary to design a boost converter with high voltage gain, low component stress, and low circuit loss. Utility Model Content

[0003] The utility model aims to provide a high-gain DCDC boost converter under DCM to overcome the shortcomings of the prior art.

[0004] A high-gain DCDC boost converter under DCM, comprising an input stage unit, a two-inductor boost unit and an output voltage stabilization unit;

[0005] The input stage unit includes a DC source Vin, a first inductor L1, a first diode D1, a first switch S1 and a first capacitor C1, one end of the first inductor L1 is connected to one end of the first diode D1, the other end of the first diode D1 is connected to the drain of the first switch S1, the other end of the first inductor L1 is connected to one end of the DC source Vin, the other end of the DC source Vin is connected to one end of the first capacitor C1, and the other end of the first capacitor C1 is connected to the source of the first switch S1;

[0006] The two-inductor boost unit includes a second inductor L2, a third inductor L3, a second switch S2, a third switch S3, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode D6, a second capacitor C2, a third capacitor C3, a fourth capacitor C4 and a fifth capacitor C5; one end of the second inductor L2 is connected to the drain of the third switch S3 and the source of the first switch S1; the other end of the second inductor L2 is connected to the other end of the first diode D1, the drain of the second switch S2, the source of the third switch S3, one end of the second diode D2 and one end of the second capacitor C2; the source of the second switch S2 is connected to the third switch S3 ... One end of the third inductor L3 is connected to one end of the first capacitor C1; the other end of the third inductor L3 is connected to the source of the third switch S3, one end of the third diode D3, and one end of the third capacitor C3; the other end of the third diode D3 is connected to the other end of the second capacitor C2, one end of the fourth diode D4, and one end of the fifth capacitor C5; the other end of the second diode D2 is connected to the other end of the third capacitor C3, one end of the fourth capacitor C4, and one end of the fifth diode D5; the other end of the fourth capacitor C4 is connected to the other end of the fourth diode D4; the other end of the fifth capacitor C5 is connected to one end of the sixth diode D6 and the other end of the fifth diode D5;

[0007] The output voltage stabilizing unit includes a sixth capacitor C6 and a resistor R, one end of the sixth capacitor C6 is connected to one end of the resistor R and the other end of the sixth diode D6, and the other end of the sixth capacitor C6 is connected to the other end of the resistor R and the other end of the fourth capacitor C4.

[0008] Preferably, the first switch S1, the second switch S2 and the third switch S3 are all MOSFET switch tubes.

[0009] Preferably, the control logic of the first switch S1 is opposite to that of the second switch S2, and the control logic of the second switch S2 is the same as that of the third switch S3.

[0010] Preferably, the first diode D1, the second diode D2, the third diode D3, the fourth diode D4, the fifth diode D5, and the sixth diode D6 are all Schottky diodes.

[0011] Preferably, the first inductor L1 and the second inductor L2 have different values.

[0012] Preferably, the second inductor L2 and the third inductor L3 have the same value.

[0013] Preferably, the first capacitor C1, the second capacitor C2, the third capacitor C3, the fourth capacitor C4, the fifth capacitor C5, and the sixth capacitor C6 are all ceramic capacitors.

[0014] Preferably, the second capacitor C2 is the same as the third capacitor C3, and the fourth capacitor C4 is the same as the fifth capacitor C5.

[0015] Compared with the prior art, the utility model has the following beneficial technical effects:

[0016] The utility model provides a high-gain DCDC boost converter under DCM, including an input stage unit, two inductor boost units and an output voltage stabilizing unit; the input stage unit is connected to the two inductor boost units, and the two inductor boost units are connected to the output voltage stabilizing unit; the circuit provided by the application can realize two working states, CCM and DCM working states, and has a better gain effect in the DCM state; in the DCM state, there are three small states respectively, when operating in the DCM mode, the converter has a larger voltage gain ratio than when operating in the CCM mode; the circuit is characterized in that less inductance is used, and the DCM converter is smaller and lighter. Thus, the goals of high gain, low component voltage stress, low circuit loss, and smaller and cheaper converters are achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A topology diagram of a high-gain DCDC boost converter under DCM provided in an embodiment of the utility model.

[0018] Figure 2 This is working mode 1 of the converter in CCM in the embodiment of the utility model.

[0019] Figure 3 This is working mode 2 of the converter in CCM in the embodiment of the utility model.

[0020] Figure 4 This is working mode 1 of the converter in DCM in the embodiment of the utility model.

[0021] Figure 5 This is working mode 2 of the converter in DCM in the embodiment of the utility model.

[0022] Figure 6 This is working mode 3 of the converter in DCM in the embodiment of the utility model. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

[0024] It should be noted that the terms "first", "second", etc. in the specification and claims of the utility model and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the utility model described here can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0025] like Figure 1 As shown, a high-gain DCDC boost converter in DCM (discontinuous conduction mode) includes an input stage unit, a two-inductor boost unit and an output voltage regulator unit;

[0026] The input stage unit is connected to two inductor boost units, and the two inductor boost units are connected to the output voltage stabilization unit. This circuit has two working states, CCM and DCM working states;

[0027] Specifically, the input stage unit includes a DC source Vin, a first inductor L1, a first diode D1, a first switch S1 and a first capacitor C1, one end of the first inductor L1 is connected to one end of the first diode D1, the other end of the first diode D1 is connected to the drain of the first switch S1, the other end of the first inductor L1 is connected to one end of the DC source Vin, the other end of the DC source Vin is connected to one end of the first capacitor C1, and the other end of the first capacitor C1 is connected to the source of the first switch S1;

[0028] The two-inductor boost unit includes a second inductor L2, a third inductor L3, a second switch S2, a third switch S3, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode D6, a second capacitor C2, a third capacitor C3, a fourth capacitor C4 and a fifth capacitor C5; one end of the second inductor L2 is connected to the drain of the third switch S3 and the source of the first switch S1; the other end of the second inductor L2 is connected to the other end of the first diode D1, the drain of the second switch S2, the source of the third switch S3, one end of the second diode D2 and one end of the second capacitor C2; the source of the second switch S2 is connected to the third switch S3 ... One end of the third inductor L3 is connected to one end of the first capacitor C1; the other end of the third inductor L3 is connected to the source of the third switch S3, one end of the third diode D3, and one end of the third capacitor C3; the other end of the third diode D3 is connected to the other end of the second capacitor C2, one end of the fourth diode D4, and one end of the fifth capacitor C5; the other end of the second diode D2 is connected to the other end of the third capacitor C3, one end of the fourth capacitor C4, and one end of the fifth diode D5; the other end of the fourth capacitor C4 is connected to the other end of the fourth diode D4; the other end of the fifth capacitor C5 is connected to one end of the sixth diode D6 and the other end of the fifth diode D5;

[0029] The output voltage stabilizing unit includes a sixth capacitor C6 and a resistor R, one end of the sixth capacitor C6 is connected to one end of the resistor R and the other end of the sixth diode D6, and the other end of the sixth capacitor C6 is connected to the other end of the resistor R and the other end of the fourth capacitor C4. At the same time, both ends of the sixth capacitor C6 and the resistor R serve as output ends and are connected to a load.

[0030] In one embodiment of the present application, Figure 1 As shown, the positive electrode of the DC source Vin is connected to one end of the first inductor L1; the other end of the first inductor L1 is respectively connected to the positive electrode of the first diode D1 and the drain of the first switch S1; the source of the first switch S1 is connected to the positive electrode of C1; the negative electrode of the DC source Vin is connected to the negative electrode of the first capacitor C1, the source of the second switch S2, and one end of the third inductor L3; the DC source Vin adopts a 30V power supply.

[0031] The two-inductor boost unit includes a second switch S2, a third switch S3, a second inductor L2, a third inductor L3, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode D6, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, and a fifth capacitor C5. The energy of this unit is provided by the input stage unit of the previous stage; one end of the second inductor L2 is connected to the positive electrode of the first capacitor C1 and the source of the first switch S1, and the other end of the second inductor L2 is connected to the drain of the second switch S2, the negative electrode of the first diode D1, the positive electrode of the second diode D2, and the positive electrode of the second capacitor C2; one end of the third inductor L3 is connected to the positive electrode of the third switch S3. The source stage, the cathode of the third diode D3, and the cathode of the third capacitor C3 are connected; the first capacitor C1, (the second inductor L2 is connected in series with the third switch S2), and (the third inductor L3 is connected in series with the third switch S3) are in parallel; the positive electrode of the third capacitor C3 is connected with the positive electrode of the fourth capacitor C4, the cathode of the second diode D2, and the positive electrode of the fifth diode D5; the negative electrode of the second capacitor C2 is connected with the positive electrode of the third diode D3, the cathode of the fourth diode D4, and the cathode of the fifth capacitor C5; the positive electrode of the fifth capacitor C5 is connected with the cathode of the fifth diode D5 and the cathode of the sixth diode D6; the negative electrode of the fourth capacitor C4 is connected with the cathode of the fourth diode D4 and the cathode of the sixth capacitor C6.

[0032] The output voltage stabilizing unit is composed of a sixth capacitor C6 and a resistor R. The sixth capacitor C6 and the resistor R are connected in parallel, and the energy is provided by the previous stage boost unit.

[0033] The first switch S1, the second switch S2, and the third switch S3 all use MOSFET switch tubes, and the control logic of the first switch S1 is opposite to that of the second switch S2, and the control logic of the second switch S2 is the same as that of the third switch S3.

[0034] The first diode D1 , the second diode D2 , the third diode D3 , the fourth diode D4 , the fifth diode D5 , and the sixth diode D6 are all Schottky diodes.

[0035] The first inductor L1 and the second inductor L2 have different values, which can make the circuit work in different working states (CCM and DCM); at the same time, the inductor value L2=L3.

[0036] The first capacitor C1, the second capacitor C2, the third capacitor C3, the fourth capacitor C4, the fifth capacitor C5, and the sixth capacitor C6 are all ceramic capacitors.

[0037] The connection charging and discharging logic of the second capacitor C2 and the third capacitor C3 is the same, which is opposite to the connection charging and discharging logic of the fourth capacitor C4 and the fifth capacitor C5. When the second capacitor C2 and the third capacitor C3 are discharged, the fourth capacitor C4 and the fifth capacitor C5 are charged. When the fourth capacitor C4 and the fifth capacitor C5 are discharged, the second capacitor C2 and the third capacitor C3 are charged; at the same time, for the capacitance values ​​C2=C3, C4=C5.

[0038] The first switch S1 is used to charge the first capacitor C1, and the first diode D1 is used to charge the first inductor L1.

[0039] The two working states are CCM and DCM working states. In the CCM state, the first inductor L1, the second inductor L2, and the third inductor L3 are all in the current continuous state; in the DCM state, there are three small states, namely, 1. The first inductor L1 is in the DCM state and the second inductor L2 and the third inductor L3 are in the CCM state; 2. The first inductor L1 is in the CCM state and the second inductor L2 and the third inductor L3 are in the DCM state; 3. The first inductor L1, the second inductor L2, and the third inductor L3 are in the DCM state at the same time. And the voltage gain of the circuit is the largest in the third DCM state.

[0040] See also Figure 2 The above is the working mode 1 of the converter under CCM. At this time, the first inductor L1, the second inductor L2, and the third inductor L3 in the circuit are all in CCM because of different values. The first switch S1 is disconnected, and the second switch S2 and the third switch S3 are turned on. At this time, the first diode D1, the fourth diode D4, and the fifth diode D5 are forward biased, and the second diode D2, the third diode D3, and the sixth diode D6 are reverse biased. The DC source Vin charges the first inductor L1 through the first diode D1 and the second switch S2, the first capacitor C1 charges the second inductor L2 and the third inductor L3, the second capacitor C2 and the third capacitor C3 are discharged, and the fourth capacitor C4 and the fifth capacitor C5 are charged; the sixth capacitor C6 supplies power to the resistor R alone.

[0041] See also Figure 3 , the converter works in CCM mode 2. At this time, the first inductor L1, the second inductor L2, and the third inductor L3 in the circuit are all in CCM because of their different values. The first switch S1 is turned on, the second switch S2 and the third switch S3 are turned off, the first diode D1, the fourth diode D4, and the fifth diode D5 are reverse biased, the second diode D2, the third diode D3, and the sixth diode D6 are forward biased, the second capacitor C2 and the third capacitor C3 are charged, and the fourth capacitor C4 and the fifth capacitor C5 are discharged, providing energy for the sixth capacitor C6 and the resistor R.

[0042] See also Figure 4, the converter works in DCM mode 1. At this time, the first inductor L1 is in DCM because of its value, that is, from T1 to T2. The second inductor L2 and the third inductor L3 are in CCM. At this time, the first inductor L1 cannot provide energy, and the second switch S2 and the third switch S3 are disconnected. The second capacitor C2 and the third capacitor C3 are charged, and the fourth capacitor C4 and the fifth capacitor C5 are discharged. The second diode D2, the third diode D3, and the sixth diode D6 are forward biased, and the fourth diode D4 and the fifth diode D5 are reverse biased.

[0043] See also Figure 5 , the converter works in DCM mode 2, at this time, the first inductor L1 is in CCM, the second inductor L2 and the third inductor L3 are in DCM, that is, the inductor is intermittent. At this time, the first switch S1 is turned on, the second switch S2 and the third switch S3 are turned off, the DC source Vin and the first inductor L1 charge the first capacitor C1 at the same time, and the sixth capacitor C6 supplies power to the resistor R alone.

[0044] See also Figure 6 The converter works in DCM mode 3. At this time, the first inductor L1, the second inductor L2, and the third inductor L3 in the circuit are all in DCM because of their different values; the sixth capacitor C6 supplies power to the resistor R alone.

[0045] The working principle of the utility model is:

[0046] The utility model provides a high-gain DCDC boost converter under DCM, including an input stage unit, a two-inductor boost unit and an output voltage stabilizing unit; the input stage unit is connected to the two-inductor boost unit, and the two-inductor boost unit is connected to the output voltage stabilizing unit; this circuit has two working states, CCM and DCM working states, and has a better gain effect in the DCM state; in the DCM state, there are three small states, namely 1. the input inductor is in the DCM state and the boost inductor is in the CCM state; 2. the input inductor is in the CCM state and the boost inductor is in the DCM state; 3. the input inductor and the boost inductor are in the DCM state at the same time. When operating in the DCM mode, the converter has a larger voltage gain ratio than when operating in the CCM mode. The circuit has the characteristics of high gain, low component voltage stress, low circuit loss, smaller and lighter converter, etc.

[0047] The above describes in detail the structure, features and effects of the utility model based on the embodiments shown in the drawings. The above is only a preferred embodiment of the utility model, but the utility model is not limited to the scope of implementation as shown in the drawings. Any changes made in accordance with the concept of the utility model, or modifications to equivalent embodiments with equivalent changes, which still do not exceed the spirit covered by the description and the drawings, should be within the protection scope of the utility model.

Claims

1. A high-gain DCDC boost converter in DCM, characterized in that: It includes an input stage unit, a two-inductor boost unit and an output voltage stabilization unit; The input stage unit includes a DC source Vin, a first inductor L1, a first diode D1, a first switch S1 and a first capacitor C1, one end of the first inductor L1 is connected to one end of the first diode D1, the other end of the first diode D1 is connected to the drain of the first switch S1, the other end of the first inductor L1 is connected to one end of the DC source Vin, the other end of the DC source Vin is connected to one end of the first capacitor C1, and the other end of the first capacitor C1 is connected to the source of the first switch S1; The two-inductor boost unit includes a second inductor L2, a third inductor L3, a second switch S2, a third switch S3, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode D6, a second capacitor C2, a third capacitor C3, a fourth capacitor C4 and a fifth capacitor C5; one end of the second inductor L2 is connected to the drain of the third switch S3 and the source of the first switch S1; the other end of the second inductor L2 is connected to the other end of the first diode D1, the drain of the second switch S2, the source of the third switch S3, one end of the second diode D2 and one end of the second capacitor C2; the source of the second switch S2 is connected to the third switch S3 ... One end of the third inductor L3 is connected to one end of the first capacitor C1; the other end of the third inductor L3 is connected to the source of the third switch S3, one end of the third diode D3, and one end of the third capacitor C3; the other end of the third diode D3 is connected to the other end of the second capacitor C2, one end of the fourth diode D4, and one end of the fifth capacitor C5; the other end of the second diode D2 is connected to the other end of the third capacitor C3, one end of the fourth capacitor C4, and one end of the fifth diode D5; the other end of the fourth capacitor C4 is connected to the other end of the fourth diode D4; the other end of the fifth capacitor C5 is connected to one end of the sixth diode D6 and the other end of the fifth diode D5; The output voltage stabilizing unit includes a sixth capacitor C6 and a resistor R, one end of the sixth capacitor C6 is connected to one end of the resistor R and the other end of the sixth diode D6, and the other end of the sixth capacitor C6 is connected to the other end of the resistor R and the other end of the fourth capacitor C4.

2. The high-gain DCDC boost converter in DCM according to claim 1, characterized in that: The first switch S1, the second switch S2 and the third switch S3 are all MOSFET switch tubes.

3. A high-gain DCDC boost converter in DCM according to claim 1 or 2, characterized in that: The control logic of the first switch S1 is opposite to that of the second switch S2 , and the control logic of the second switch S2 is the same as that of the third switch S3 .

4. The high-gain DCDC boost converter in DCM according to claim 1, characterized in that: The first diode D1 , the second diode D2 , the third diode D3 , the fourth diode D4 , the fifth diode D5 , and the sixth diode D6 are all Schottky diodes.

5. The high-gain DCDC boost converter in DCM according to claim 1, characterized in that: The first inductor L1 and the second inductor L2 have different values.

6. The high-gain DCDC boost converter in DCM according to claim 5, characterized in that: The second inductor L2 and the third inductor L3 have the same value.

7. The high-gain DCDC boost converter in DCM according to claim 1, characterized in that: The first capacitor C1, the second capacitor C2, the third capacitor C3, the fourth capacitor C4, the fifth capacitor C5, and the sixth capacitor C6 are all ceramic capacitors.

8. The high-gain DCDC boost converter in DCM according to claim 1, characterized in that: The second capacitor C2 and the third capacitor C3 are the same.

9. The high-gain DCDC boost converter in DCM according to claim 1, characterized in that: The fourth capacitor C4 and the fifth capacitor C5 are the same.

Images