Double-input medium-gain DC-DC boost converter

Abstract

The utility model discloses a double-input medium-gain DC-DC boost converter, which is provided with two current feed input ports which respectively extract power from a battery source and a one-way DC power supply and feed the power to a load. Compared with a classic boost converter, the converter can obtain a higher voltage ratio and lower voltage stress on a power switch by utilizing the switched capacitor voltage multiplication unit. Under the condition that no auxiliary active circuit exists, ZVS is executed on all power switch tubes, ZCS is executed on body diodes and power diodes, and the converter has the advantages that the structure is simple and compact, the number of current feed input ports, the number of power switches and the number of magnetic elements are small, the voltage stress across the power switches is low, and medium-voltage gain and high efficiency are achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of DC-DC converters, and in particular relates to a dual-input medium-gain DC-DC boost converter. Background Art

[0002] The microgrid system composed of green and clean energy such as solar energy is developing more and more rapidly, and the utilization rate of converters with two inputs has increased, and the bidirectional function of charging and discharging is realized through the energy storage port; At present, the traditional boost DC-DC circuit has low converter efficiency, low energy conversion rate, large switching loss, high voltage stress, and it is difficult to achieve ZVS and ZCS. In order to solve the above problems, a dual-input medium-gain DC-DC boost converter with soft switching performance is proposed. Utility Model Content

[0003] The utility model aims to provide a dual-input medium-gain DC-DC boost converter to overcome the shortcomings of the prior art.

[0004] A dual-input medium-gain DC-DC boost converter, comprising a DC input power supply VA, a rechargeable DC energy storage VB, a first power switch tube S1, a second power switch tube S2, a third power switch tube S3, a first inductor L1, a second inductor L2, a third inductor L3, a first DC capacitor C1, a second DC capacitor C2, a third DC capacitor C3, a fourth DC capacitor C4, a power diode D4, a power diode D5, and an output load R;

[0005] The positive electrode of the DC input power supply VA is connected to the first end of the second inductor L2, and the negative electrode of the DC input power supply VA is respectively connected to the negative electrode of the rechargeable DC energy storage VB, the source electrode of the power switch tube S1, the second end of the first DC capacitor C1, the second end of the second DC capacitor C4 and the second end of the output load R;

[0006] The positive electrode of the rechargeable DC energy storage VB is connected to the first end of the first inductor L1;

[0007] The second end of the first inductor L1 is connected to the drain of the first power switch tube S1, the source of the second power switch tube S2 and the first end of the third inductor L3;

[0008] The second end of the second inductor L2 is connected to the drain of the second power switch tube S2, the source of the third power switch tube S3 and the second end of the third DC capacitor C3;

[0009] The second end of the third inductor L3 is connected to the first end of the first DC capacitor C1 and the second end of the second DC capacitor C2;

[0010] The drain of the first power switch tube S1 is connected to the source of the second power switch tube S2 and the first end of the third inductor L3;

[0011] The drain of the second power switch tube S2 is connected to the source of the third power switch tube S3, the second end of the second inductor L2 and the second end of the third DC capacitor C3;

[0012] The drain of the third power switch tube S3 is connected to the anode of the power diode D4 and the first end of the second DC capacitor C2;

[0013] The first end of the first DC capacitor C1 is connected to the second end of the third inductor L3 and the second end of the second DC capacitor C2;

[0014] The first end of the third DC capacitor C3 is connected to the cathode of the power diode D4 and the anode of the power diode D5;

[0015] The anode of the power diode D5 is connected to the cathode of the power diode D4 , and the cathode of the power diode D5 is connected to the first end of the fourth DC capacitor C4 and the first end of the resistor.

[0016] Preferably, a body diode D1 is connected between the source and drain of the power switch tube S1 , the source of the power switch tube S1 is connected to the anode of the body diode D1 , and the drain of the power switch tube S1 is connected to the cathode of the body diode D1 .

[0017] Preferably, a body diode D2 is connected between the source and drain of the power switch tube S2, the source of the power switch tube S2 is connected to the anode of the body diode D2, and the drain of the power switch tube S2 is connected to the cathode of the body diode D2.

[0018] Preferably, a body diode D3 is connected between the source and drain of the power switch tube S3 , the source of the power switch tube S3 is connected to the anode of the body diode D3 , and the drain of the power switch tube S3 is connected to the cathode of the body diode D3 .

[0019] Preferably, the first inductor L1, the second inductor L2, and the third inductor L3 are all energy storage inductors.

[0020] Preferably, the voltage of the DC input power supply VA is greater than the voltage of the rechargeable DC energy storage VB.

[0021] Preferably, the duty cycles of the power switch tube S1 and the power switch tube S2 are D1 and D2 respectively, and the duty cycle of the power switch tube S3 is D3=2-D2-D1.

[0022] Preferably, the first DC capacitor C1 and the second DC capacitor C2 are connected in series to form a clamping stage of the converter circuit, V CL =VC1 +V C2 .

[0023] Compared with the prior art, the utility model has the following beneficial technical effects:

[0024] The utility model provides a dual-input medium-gain DC-DC boost converter. The proposed converter has two current-feeding input ports, which respectively extract power from a battery source and a unidirectional DC power supply and feed it to a load. Compared with a classical boost converter, the converter can obtain a higher voltage ratio and lower voltage stress on the power switch by using a switched capacitor voltage multiplication unit. In the absence of any auxiliary active circuit, ZVS is performed on all power switch tubes, and ZCS is performed on the body diode and the power diode. The converter has the advantages of simple and compact structure, small number of current-feeding input ports, power switches and magnetic components, low voltage stress across the power switch, medium voltage gain and high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of a dual-input medium-gain DC-DC boost converter circuit in an embodiment of the utility model.

[0026] Figure 2 Schematic diagram of working mode 1 of a dual-input medium-gain DC-DC boost converter circuit in an embodiment of the present utility model.

[0027] Figure 3 Schematic diagram of working mode 2 of a dual-input medium-gain DC-DC boost converter circuit in an embodiment of the utility model.

[0028] Figure 4 Schematic diagram of working mode 3 of a dual-input medium-gain DC-DC boost converter circuit in an embodiment of the utility model.

[0029] Figure 5 Schematic diagram of working mode 4 of a dual-input medium-gain DC-DC boost converter circuit in an embodiment of the present utility model.

[0030] Figure 6 Schematic diagram of working mode 5 of a dual-input medium-gain DC-DC boost converter circuit in an embodiment of the present utility model.

[0031] Figure 7 Schematic diagram of working mode 6 of a dual-input medium-gain DC-DC boost converter circuit in an embodiment of the present utility model.

[0032] Figure 8 Schematic diagram of working mode 7 of a dual-input medium-gain DC-DC boost converter circuit in an embodiment of the present utility model.

[0033] Fig. 9Schematic diagram of working mode 8 of a dual-input medium-gain DC-DC boost converter circuit in an embodiment of the present utility model. DETAILED DESCRIPTION

[0034] 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.

[0035] 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.

[0036] like Figure 1 As shown, the utility model provides a dual-input medium-gain DC-DC boost converter, including a DC input power supply VA, a rechargeable DC energy storage VB, a first power switch tube S1, a second power switch tube S2, a third power switch tube S3, a first inductor L1, a second inductor L2, a third inductor L3, a first DC capacitor C1, a second DC capacitor C2, a third DC capacitor C3, a fourth DC capacitor C4, a body diode D1, a body diode D2, a body diode D3, a power diode D4, a power diode D5, and an output load R;

[0037] The positive electrode of the DC input power supply VA is connected to the first end of the second inductor L2, and the negative electrode of the DC input power supply VA is respectively connected to the negative electrode of the rechargeable DC energy storage VB, the source electrode of the power switch tube S1, the second end of the first DC capacitor C1, the second end of the second DC capacitor C4 and the second end of the output load R;

[0038] The positive electrode of the rechargeable DC energy storage VB is connected to the first end of the first inductor L1;

[0039] The second end of the first inductor L1 is connected to the drain of the first power switch tube S1, the source of the second power switch tube S2 and the first end of the third inductor L3;

[0040] The second end of the second inductor L2 is connected to the drain of the second power switch tube S2, the source of the third power switch tube S3 and the second end of the third DC capacitor C3;

[0041] The second end of the third inductor L3 is connected to the first end of the first DC capacitor C1 and the second end of the second DC capacitor C2;

[0042] The drain of the first power switch tube S1 is connected to the source of the second power switch tube S2 and the first end of the third inductor L3;

[0043] The drain of the second power switch tube S2 is connected to the source of the third power switch tube S3, the second end of the second inductor L2 and the second end of the third DC capacitor C3;

[0044] The drain of the third power switch tube S3 is connected to the anode of the power diode D4 and the first end of the second DC capacitor C2;

[0045] The first end of the first DC capacitor C1 is connected to the second end of the third inductor L3 and the second end of the second DC capacitor C2;

[0046] The first end of the third DC capacitor C3 is connected to the cathode of the power diode D4 and the anode of the power diode D5;

[0047] The anode of the power diode D5 is connected to the cathode of the power diode D4 , and the cathode of the power diode D5 is connected to the first end of the fourth DC capacitor C4 and the first end of the resistor.

[0048] The source of the power switch tube S1 is connected to the anode of the body diode D1, and the drain of the power switch tube S1 is connected to the cathode of the body diode D1; the source of the power switch tube S2 is connected to the anode of the body diode D2, and the drain of the power switch tube S2 is connected to the cathode of the body diode D2; the source of the power switch tube S3 is connected to the anode of the body diode D3, and the drain of the power switch tube S3 is connected to the cathode of the body diode D3.

[0049] The first inductor L1 , the second inductor L2 , and the third inductor L3 are all energy storage inductors.

[0050] In a dual input medium gain DC-DC boost converter, V A >V BThe converter switches asynchronously in PWM mode. The duty ratios of the power switch tubes S1 and S2 are D1 and D2 respectively. The duty ratio of the power switch tube S3 is D3 = 2-D2-D1. The conduction point of the power switch tube S1 is set at the moment when the power switch tube S1 is turned off. The power switch tube S3 is also turned on when the power switch tube S2 is turned off. The first DC capacitor C1 and the second DC capacitor C2 are connected in series to form the clamping stage of the converter circuit. There is V CL =V C1 +V C2 .

[0051] Working Mode 1

[0052] like Figure 2 As shown, the power switch tube S1 is turned on, while the power switch tube S2 and the power switch tube S3 remain in the previous on and off states respectively. Figure 2 At the same time, due to i C3 The forward current of the capacitor C3 decreases, but there is still a positive current flowing through the power diode D4, so the voltage of the DC capacitor C3 is V C3 =V CL When the power switch tube S1 is turned on, the current i L1 、i L2 and i L3 At the minimum value, as time changes, the charging DC voltage V B , inductor L1, power switch tube S1 circuit, V L1 =V B >0, at DC voltage V A , inductor L2, power switch tube S2, power switch tube S1 loop, there is V L2 =V A >0, the voltage V across the loop DC capacitor C1 C1 , in inductor L3 and power switch tube S1, there is V L3 =V C2 >0, the current will increase linearly.

[0053] Working Mode 2

[0054] Current i C3 reaches zero after the last moment, thereby stopping the conduction of the power diode D4 under the ZCS condition, as Figure 3 As shown. L1 、i L2 and i L3 Still the same as Mode 1 working mode.

[0055] Working Mode 3

[0056] like Figure 4After the previous mode, the power switch tube S2 is turned off, and the body diode D3 of the power switch tube S3 begins to conduct, and the current flowing through is i L2 , so they will each carry a portion of i L2 To the converter clamping stage and output load. As the first dead zone of the converter, the conduction state of the body diode D3 provides the condition for the ZVS conduction of the power switch tube S3.

[0057] Working Mode 4

[0058] like Figure 5 As shown, in this state, the power switch tube S3 works in ZVS to form a converter circuit. C3 The negative current will pass through the power diode D5 to the output stage. Therefore, V CL +V C3 =V C4 . Since V L1 =V B >0,V L3 =V C1 >0, inductors L1 and L3 are connected through V B , the voltage V across the inductor L1, the power switch tube S1 and the DC capacitor C1 C1 The circuit loop consisting of the inductor L3 and the power switch tube S1 is in a charging state. Therefore, the current i L1 and i L3 At the end of this mode, the maximum value is reached. Similarly, the inductor L2 is connected to the DC voltage V A , inductor L2, power switch tube S3, V CL The circuit loop is discharged, at this time V L2 =V A -V CL <0.

[0059] Working Mode 5

[0060] like Figure 6 As shown, when the power switch tube S1 is turned off, the body diode D2 of the power switch tube S2 begins to conduct, generating a current i L1 +i L3 , forming a ZVS condition at the moment of forward conduction, after which the current is distributed between the two paths of D3 and C3, and i L2 The same, so it will be turned on at a higher current level, this state is called the second dead zone, but its duration is very short.

[0061] Working Mode 6

[0062] like Figure 7 As shown, the power switch S2 is turned on in ZVS mode. In this mode, i L1 +i L2 +iL3 The current is distributed between the body diode D3 and the DC capacitor C3, and the power diode D5 divides the negative current i C3 Transmitted to the converter output load, the voltage relationship is V CL +V C3 =V C4 , in the rechargeable DC energy storage V B , inductor L1, power switch tube S2, DC capacitor C3, power diode D5, DC capacitor C4 constitute the loop, there is V L1 =V B +V C3 -V C4 <0, at DC voltage V A , inductor L2, power switch tube S3, voltage V CL In the circuit formed, there is V L2 =V A -V CL <0, in the loop composed of DC capacitor C1, inductor L3, power switch tube S2, DC capacitor C3, power diode D5, and DC capacitor C4, there is V L3 =V C1 +V C3 -V C4 <0.

[0063] Working mode 7:

[0064] like Figure 8 As shown, C3 = 0, the power diode D5 stops conducting under ZCS conditions. All voltage and current conditions of inductors L1, L2, and L3 remain the same as in the previous operating mode.

[0065] Working Mode 8:

[0066] like Fig. 9 As shown in the figure, the working mode starts when the power switch tube S3 is turned off, so the body diode D1 of the power switch tube S1 immediately starts to conduct to carry the switching current. Since the negative polarity voltage of the body tube D1, the DC capacitor C3 and the cathode voltage of the power diode D4 are pulled down by V CL Therefore, power diode D4 becomes forward biased, while power diode D5 remains reverse biased. This state is the third dead time interval of the converter, providing a ZVS condition for switch S1.

[0067] The present application provides a dual-input medium-gain DC-DC boost converter, which has two current-fed input ports, respectively extracting power from a battery source and a unidirectional DC power supply, and feeding it to a load. Compared with a classical boost converter, the use of a switched capacitor voltage multiplier unit enables the converter to obtain a higher voltage ratio and lower voltage stress on the power switch. In the absence of any auxiliary active circuit, ZVS is performed on all power switches and ZCS is performed on power diodes. This provides low switching power losses and reduces reverse recovery problems. By designing the converter inductance value, it can have soft switching performance over the entire power range of the input source and output load. A PWM scheme is adopted to switch the three power field effect transistors of the converter with two independent duty cycles. The output voltage is regulated by the first duty cycle, and the second duty cycle is responsible for regulating the output power of the input source.

[0068] The converter provided by the utility model has two current feeding input ports, which respectively extract power from a battery source and a unidirectional DC power supply and feed it to a load. Compared with a classic boost converter, the converter can obtain a higher voltage ratio and lower voltage stress on the power switch by using a switch capacitor voltage multiplication unit. In the absence of any auxiliary active circuit, ZVS is performed on all power switch tubes, and ZCS is performed on the body diode and the power diode. The converter has the advantages of simple and compact structure, small number of current feeding input ports, power switches and magnetic components, low voltage stress across the power switch, medium voltage gain and high efficiency.

Claims

1. A dual-input medium-gain DC-DC boost converter, characterized in that: It includes a DC input power supply VA, a rechargeable DC energy storage VB, a first power switch tube S1, a second power switch tube S2, a third power switch tube S3, a first inductor L1, a second inductor L2, a third inductor L3, a first DC capacitor C1, a second DC capacitor C2, a third DC capacitor C3, a fourth DC capacitor C4, a power diode D4, a power diode D5, and an output load R; The positive electrode of the DC input power supply VA is connected to the first end of the second inductor L2, and the negative electrode of the DC input power supply VA is respectively connected to the negative electrode of the rechargeable DC energy storage VB, the source electrode of the power switch tube S1, the second end of the first DC capacitor C1, the second end of the second DC capacitor C4 and the second end of the output load R; The positive electrode of the rechargeable DC energy storage VB is connected to the first end of the first inductor L1; The second end of the first inductor L1 is connected to the drain of the first power switch tube S1, the source of the second power switch tube S2 and the first end of the third inductor L3; The second end of the second inductor L2 is connected to the drain of the second power switch tube S2, the source of the third power switch tube S3 and the second end of the third DC capacitor C3; The second end of the third inductor L3 is connected to the first end of the first DC capacitor C1 and the second end of the second DC capacitor C2; The drain of the first power switch tube S1 is connected to the source of the second power switch tube S2 and the first end of the third inductor L3; The drain of the second power switch tube S2 is connected to the source of the third power switch tube S3, the second end of the second inductor L2 and the second end of the third DC capacitor C3; The drain of the third power switch tube S3 is connected to the anode of the power diode D4 and the first end of the second DC capacitor C2; The first end of the first DC capacitor C1 is connected to the second end of the third inductor L3 and the second end of the second DC capacitor C2; The first end of the third DC capacitor C3 is connected to the cathode of the power diode D4 and the anode of the power diode D5; The anode of the power diode D5 is connected to the cathode of the power diode D4 , and the cathode of the power diode D5 is connected to the first end of the fourth DC capacitor C4 and the first end of the resistor.

2. A dual-input medium-gain DC-DC boost converter according to claim 1, characterized in that: A body diode D1 is connected between the source and drain of the power switch tube S1 , the source of the power switch tube S1 is connected to the anode of the body diode D1 , and the drain of the power switch tube S1 is connected to the cathode of the body diode D1 .

3. A dual-input medium-gain DC-DC boost converter according to claim 2, characterized in that: A body diode D2 is connected between the source and drain of the power switch tube S2 , the source of the power switch tube S2 is connected to the anode of the body diode D2 , and the drain of the power switch tube S2 is connected to the cathode of the body diode D2 .

4. A dual-input medium-gain DC-DC boost converter according to claim 3, characterized in that: A body diode D3 is connected between the source and drain of the power switch tube S3 , the source of the power switch tube S3 is connected to the anode of the body diode D3 , and the drain of the power switch tube S3 is connected to the cathode of the body diode D3 .

5. The dual-input medium-gain DC-DC boost converter according to claim 1, characterized in that: The first inductor L1 , the second inductor L2 , and the third inductor L3 are all energy storage inductors.

6. The dual-input medium-gain DC-DC boost converter according to claim 1, characterized in that: The voltage of the DC input power source VA is greater than the voltage of the rechargeable DC energy storage VB.

7. A dual-input medium-gain DC-DC boost converter according to claim 4, characterized in that: The duty cycles of the power switch tube S1 and the power switch tube S2 are D1 and D2 respectively, and the duty cycle of the power switch tube S3 is D3=2-D2-D1.

8. The dual-input medium-gain DC-DC boost converter according to claim 1, characterized in that: The first DC capacitor C1 and the second DC capacitor C2 are connected in series to form the clamping stage of the converter circuit. CL =V C1 +V C2 .

Images