High-frequency three-port DC-DC converter with zero-voltage switching operation

Abstract

A high-frequency three-port DC-DC converter with zero-voltage switching operation comprises an input voltage source Vbat, an output voltage source VH, a first voltage source Vin, a first capacitor C1P, a second capacitor C2P, a third capacitor C3, a fourth capacitor C1S, a fifth capacitor C2S, a first stray capacitor CS1P, a second stray capacitor CS2P, a third stray capacitor CS1S, a fourth stray capacitor CS2S, a first inductor L1, a second inductor L2 and an excitation inductor Lm. The circuit comprises a first power switch tube S1P, a second power switch tube S2P and a third power switch tube S1S, in the mode 1, the first stray capacitor CS1P is discharged, and the second stray capacitor CS2P is charged; in the mode 2, the first switch tube S1P and the third switch tube S1S apply pulses and are turned on in the ZVS state; in the mode 3, the first stray capacitor CS1P is discharged, and the second stray capacitor CS2P is charged; in the mode 4, the second switch tube S2P and the fourth switch tube S2S are conducted to the ZVS state at the moment t3; the utility model has the characteristics of small volume, simple switching mode, high efficiency and high power density.

Description

Technical Field

[0001] This utility model belongs to the field of renewable energy power generation technology, specifically relating to a high-frequency three-port DC-DC converter with zero-voltage switching operation. Background Technology

[0002] Because renewable energy sources are dependent on environmental change, they need to interface with storage units (such as batteries) to continuously power loads. Therefore, a three-port DC-DC converter (TPC) helps to increase the generated voltage to a suitable level and store energy in battery cells to power loads when mains power is unavailable. TPCs can be used to power home appliances, space applications, hybrid vehicles, microgrids, and other applications.

[0003] An optical TPC is an integration of multiple single-input single-output (SIO) DC-DC converters. Utilizing several SIO converters to store energy and then restore it to the load requires more equipment. The current isolation requirements of TPCs are mainly divided into three types: non-isolated, isolated, and partially isolated. Non-isolated TPCs have the advantages of small size, integration, and low-cost design. However, their application is limited because electrical isolation is clearly required in most renewable energy conversion applications.

[0004] Fully isolated TPCs are constructed from transformers with multiple windings, or from multiple dual-winding transformers. Therefore, each port is isolated from the other. Because each port has a separate transformer winding, the voltage can be easily increased or decreased. Multiple windings increase the size, cost, and weight of these converters. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the purpose of this utility model is to provide a high-frequency three-port DC-DC converter with zero-voltage switching operation, which improves the disadvantages of the prior art such as limited application capabilities, large size of the converter, and high cost. It has the following features: 1) small size planar high-frequency transformer, 2) three different DC voltages connected in three DC ports, 3) high voltage gain, 4) zero-voltage switching capability of all four switches, 5) simple switching mode, 6) nonlinear digital control scheme for all duty cycle ranges, 7) small size, 8) high switching frequency, and 9) high efficiency.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0007] A high-frequency three-port DC-DC converter with zero-voltage switching operation includes an input voltage source V. bat Output voltage source V H First voltage source V in The first capacitor C1P The second capacitor C 2P The third capacitor C3, the fourth capacitor C 1S The fifth capacitor C 2S First parasitic capacitance C S1P The second parasitic capacitance C S2P The third parasitic capacitance C S1S The fourth parasitic capacitance C S2S First inductor L1, second inductor L2, magnetizing inductor L m Leakage L k First power switch S 1P Second power switch S 2P Third power switch S 1S Fourth power switch S 2S The ratio is 1:n t Transformer;

[0008] The first power switch S 1P With the first parasitic capacitance C S1P Parallel connection, second power switch S 2P With the second parasitic capacitance C S2P Parallel connection, third power switch S 1S With the third parasitic capacitance C S1S Parallel connection, fourth power switch S 2S With the fourth parasitic capacitance C S2S Parallel connection; input voltage source V bat First terminal and second capacitor C 2P The first terminal and the second switch S 2P The collectors of the second capacitor C are all connected; 2P The second terminal and the first capacitor C 1P The first terminal of the capacitor is connected to the first terminal of the second inductor L2; the first capacitor C 1P The second terminal and the input voltage source V bat The second terminal is connected to the second power switch S. 2P The emitter and the second terminal of the second inductor L2 are connected to the first capacitor C. 1P The first terminal is connected to the first terminal of the first inductor L1 and the first voltage source V. in The first terminal is connected; the second terminal of the first inductor L1 is connected to the first power switch S. 1P collector connection, first voltage source V pv The second terminal and the first capacitor C 1P The second terminal, the first power switch S 1P The emitters are all connected; the second terminal of the third capacitor C3 and the magnetizing inductor L m The first terminal is connected to the corresponding terminal on the primary side of the transformer; the magnetizing inductance L m The second end and leakage inductance Lk The first terminal is connected to the opposite terminal of the primary side of the transformer; leakage inductance L k The second terminal and the first power switch S 1P The emitter connection; the corresponding terminal on the secondary side of the transformer and the fourth power switch S 2S The emitter, the third power switch S 1S The collectors of the transistors are connected; the fourth power switch S... 2S The collector and the fourth capacitor C 1S First terminal, output voltage source V H The first terminal is connected; the output voltage source V H The second end is connected in sequence to the fifth capacitor C. 2S The second and third power switching transistors S 1S The emitter is connected; the fourth capacitor C 1S The first terminal and the fifth capacitor C 2S The second end is connected to the opposite end of the transformer secondary side.

[0009] First power switch S 1P Second power switch S 2P Third power switch S 1S Fourth power switch S 2S The IGBT switching transistor is model RB520S30T1G.

[0010] The input voltage source V bat Output voltage source V H First voltage source V pv The voltage values ​​are 50V, 250V, and 125V respectively.

[0011] The beneficial effects of this utility model are:

[0012] Compared with existing technologies, this invention proposes a high-frequency three-port DC-DC converter with zero-voltage switching operation, and the proposed circuit has bidirectional operating characteristics. In the proposed converter, the main transformer is used to isolate the low DC voltage port and the high DC voltage port, and increases the voltage conversion ratio of the secondary port supplying the load. The proposed converter is a partially isolated TPC, which has the advantage of electrical isolation between one port interfaced with the main load and the other two ports (input and storage ports), which are non-isolated and share a common ground.

[0013] This invention features a compact isolation structure, interfaces with three different DC voltages in three DC ports, offers bidirectional operation, high voltage gain, zero-voltage switching operation for all four switches, a simple switching mode, and a simple control method for all duty cycle ranges of boost and buck operations. Utilizing a nonlinear digital control system, it achieves smaller size, higher operating frequency, higher efficiency, and higher power density.

[0014] The converter of this invention has bidirectional operation characteristics; the proposed converter has achieved a small-volume isolation structure, interfaces with three different DC voltages in three DC ports, has bidirectional operation, high voltage gain, zero-voltage switching operation of all four switches, simple switching mode, and simple control method for all duty cycle ranges of boost and buck operations. It utilizes a nonlinear digital control system, resulting in smaller size, higher operating frequency, higher efficiency, and higher power density. Attached Figure Description

[0015] Figure 1 This is a topology diagram of the high-frequency three-port DC-DC converter with zero-voltage switching operation according to this invention.

[0016] Figure 2 This is a schematic diagram of the working mode 1 of the high-frequency three-port DC-DC converter with zero-voltage switching operation according to this utility model.

[0017] Figure 3 This is a schematic diagram of the operating mode 2 of the high-frequency three-port DC-DC converter with zero-voltage switching operation according to this utility model.

[0018] Figure 4 This is a schematic diagram of the operating mode 3 of the high-frequency three-port DC-DC converter with zero-voltage switching operation according to this utility model.

[0019] Figure 5 This is a schematic diagram of the operating mode 4 of the high-frequency three-port DC-DC converter with zero-voltage switching operation according to this utility model. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0021] It should be noted that the terms "first," "second," etc., in the specification, claims, and drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0022] It should be understood that the data used in this way can be interchanged where appropriate so that the embodiments of the present invention described herein can be implemented in a sequence other than those illustrated or described herein.

[0023] It should be understood that the data used in this way can be interchanged where appropriate so that the embodiments of the present invention described herein can be implemented in a sequence other than those illustrated or described herein. Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, products, or apparatus.

[0024] The present invention will now be described in further detail with reference to the accompanying drawings.

[0025] See Figure 1 This utility model relates to a high-frequency three-port DC-DC converter with zero-voltage switching operation, characterized in that it includes an input voltage source V. bat Output voltage source V H First voltage source V in The first capacitor C 1P The second capacitor C 2P The third capacitor C3, the fourth capacitor C 1S The fifth capacitor C 2S First parasitic capacitance C S1P The second parasitic capacitance C S2P The third parasitic capacitance C S1S The fourth parasitic capacitance C S2S First inductor L1, second inductor L2, magnetizing inductor L m Leakage L k First power switch S 1P Second power switch S 2P Third power switch S 1S Fourth power switch S 2S The ratio is 1:n t Transformer;

[0026] The first power switch S 1P With the first parasitic capacitance C S1P Parallel connection, second power switch S 2P With the second parasitic capacitance C S2PParallel connection, third power switch S 1S With the third parasitic capacitance C S1S Parallel connection, fourth power switch S 2S With the fourth parasitic capacitance C S2S Parallel connection; input voltage source V bat First terminal and second capacitor C 2P The first terminal and the second switch S 2P The collectors of the second capacitor C are all connected; 2P The second terminal and the first capacitor C 1P The first terminal of the capacitor is connected to the first terminal of the second inductor L2; the first capacitor C 1P The second terminal and the input voltage source V bat The second terminal is connected to the second power switch S. 2P The emitter and the second terminal of the second inductor L2 are connected to the first capacitor C. 1P The first terminal is connected to the first terminal of the first inductor L1 and the first voltage source V. in The first terminal is connected; the second terminal of the first inductor L1 is connected to the first power switch S. 1P collector connection, first voltage source V pv The second terminal and the first capacitor C 1P The second terminal, the first power switch S 1P The emitters are all connected; the second terminal of the third capacitor C3 and the magnetizing inductor L m The first terminal is connected to the corresponding terminal on the primary side of the transformer; the magnetizing inductance L m The second end and leakage inductance L k The first terminal is connected to the opposite terminal of the primary side of the transformer; leakage inductance L k The second terminal and the first power switch S 1P The emitter connection; the corresponding terminal on the secondary side of the transformer and the fourth power switch S 2S The emitter, the third power switch S 1S The collectors of the transistors are connected; the fourth power switch S... 2S The collector and the fourth capacitor C 1S First terminal, output voltage source V H The first terminal is connected; the output voltage source V H The second end is connected in sequence to the fifth capacitor C. 2S The second and third power switching transistors S 1S The emitter is connected; the fourth capacitor C 1S The first terminal and the fifth capacitor C 2S The second end is connected to the opposite end of the transformer secondary side.

[0027] The working process of this utility model is described below:

[0028] In this operation, the low-pressure Vin It is used as an input power source. It provides a higher voltage V. bat and V H , can be regarded as R b and R H The output load. In single-input dual-output mode operation, the first power switch S... 1P Second power switch S 2P Third power switch S 1S Internal diode (D) S1S D S2S ) switch and internal diode (D S1P D S2P All of them are active.

[0029] Working mode 1: such as Figure 2 As shown, the second switch S 2P It is turned off at time t0. The second switch S 2P Second parasitic capacitance C S2P The voltage across the transistor is 0, therefore the switching transistor is turned off with zero voltage. In this mode, the first parasitic capacitance C S1P Discharge, second parasitic capacitance C S2P Charge.

[0030] Working mode 2: such as Figure 3 As shown, in this mode, diode D first... S1P and D S1S Start conducting, then supply power to the first switching transistor S. 1P and the third switch S 1S When a pulse is applied (when the voltage across the switches is zero), they are turned on in ZVS state.

[0031] Working mode 3: such as Figure 4 As shown, the second switch S 2P It is turned off at time t0. The second switch S 2p Second parasitic capacitance C S2P The voltage across the transistor is 0, therefore the switching transistor is turned off with zero voltage. In this mode, the first parasitic capacitance C S1P Discharge, second parasitic capacitance C S2P Charge.

[0032] Working mode 4: such as Figure 5 As shown, in this mode, diode D is first... S2S and D S2P Turn on, and then at time t3, turn on the second switch S. 2P and the fourth switch S 2S Switch to ZVS state.

[0033] Where, assuming capacitor C 1P C2P C3, C 1S and C 2S Large enough that the voltage between them can be considered as V respectively. C1P V C2P V C3 V C1S and V C2S The constant value of L. Utilizing the auxiliary inductance of L and the capacitor C. 1P C 2P This achieves the ZVS conduction condition for the switch. To achieve the switch S... 1P S 2P For ZVS to be turned on, firstly, their main diodes (D) S1P D S2P The diodes are turned on, and after a short time, their trigger pulses are applied, which then turn off the internal diode D. S1P D S2P S 1P S 2P Open in ZVS mode.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it; although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A high-frequency three-port DC-DC converter with zero-voltage switching operation, characterized in that, Including input voltage source V bat Output voltage source V H First voltage source V in The first capacitor C 1P The second capacitor C 2P The third capacitor C3, the fourth capacitor C 1S The fifth capacitor C 2S First parasitic capacitance C S1P The second parasitic capacitance C S2P The third parasitic capacitance C S1S The fourth parasitic capacitance C S2S First inductor L1, second inductor L2, magnetizing inductor L m Leakage L k First power switch S 1P Second power switch S 2P Third power switch S 1S Fourth power switch S 2S The ratio is 1:n t Transformer; The first power switch S 1P With the first parasitic capacitance C S1P Parallel connection, second power switch S 2P With the second parasitic capacitance C S2P Parallel connection, third power switch S 1S With the third parasitic capacitance C S1S Parallel connection, fourth power switch S 2S With the fourth parasitic capacitance C S2 Input voltage source V bat First terminal and second capacitor C 2P The first terminal and the second switch S 2P The collectors of the second capacitor C are all connected; 2P The second terminal and the first capacitor C 1P The first terminal of the capacitor is connected to the first terminal of the second inductor L2; the first capacitor C 1P The second terminal and the input voltage source V bat The second terminal is connected to the second power switch S. 2P The emitter and the second terminal of the second inductor L2 are connected to the first capacitor C. 1P The first terminal is connected to the first terminal of the first inductor L1 and the first voltage source V. in The first terminal is connected; the second terminal of the first inductor L1 is connected to the first power switch S. 1P collector connection, first voltage source V pv The second terminal and the first capacitor C 1P The second terminal, the first power switch S 1P The emitters are all connected; the second terminal of the third capacitor C3 and the magnetizing inductor L m The first terminal is connected to the corresponding terminal on the primary side of the transformer; the magnetizing inductance L m The second end and leakage inductance L k The first terminal is connected to the opposite terminal of the primary side of the transformer; leakage inductance L k The second terminal and the first power switch S 1P The emitter connection; the corresponding terminal on the secondary side of the transformer and the fourth power switch S 2S The emitter, the third power switch S 1S The collectors of the transistors are connected; the fourth power switch S... 2S The collector and the fourth capacitor C 1S First terminal, output voltage source V H The first terminal is connected; the output voltage source V H The second end is connected in sequence to the fifth capacitor C 2S The second and third power switching transistors S 1S The emitter is connected; the fourth capacitor C 1S The first terminal and the fifth capacitor C 2S The second end is connected to the opposite end of the transformer secondary side.

2. A high-frequency three-port DC-DC converter with zero-voltage switching operation according to claim 1, characterized in that, First power switch S 1P Second power switch S 2P Third power switch S 1S Fourth power switch S 2S The IGBT switching transistor is model RB520S30T1G.

3. A high-frequency three-port DC-DC converter with zero-voltage switching operation according to claim 1, characterized in that, The input voltage source V bat Output voltage source V H First voltage source V pv The voltage values ​​are 50V, 250V, and 125V respectively.

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