CN-224218284-U - Isolated high-frequency DC/DC converter

CN224218284UCN 224218284 UCN224218284 UCN 224218284UCN-224218284-U

Abstract

The utility model discloses an isolated high-frequency DC/DC converter which comprises an upper half-bridge resonant converter, a lower half-bridge resonant converter, a first isolation transformer T1, a second isolation transformer T2 and a rectifying circuit, wherein the upper half-bridge resonant converter and the lower half-bridge resonant converter adopt heterogeneous designs, and only one thyristor is conducted at any time T through a first thyristor K1 and a second thyristor K2, so that time-sharing multiplexing control of the upper half-bridge resonant converter and the lower half-bridge resonant converter is realized, and the voltage gain range and the operation efficiency of the converter are improved.

Inventors

DONG JIHUI
WU XUEGANG
FAN ZHIQIANG
QIU YONG
FU XIANGJUN
LI YINHAO
HE SONGSONG
ZHANG XIUWEI

Assignees

内蒙古察哈尔新能源有限公司
新源智储能源发展(北京)有限公司

Dates

Publication Date: 20260508
Application Date: 20250415

Claims (8)

1. The isolation type high-frequency DC/DC converter comprises a primary side circuit, a first isolation transformer T1, a second isolation transformer T2 and a rectifying circuit, and is characterized in that the primary side circuit comprises an upper half-bridge resonant converter and a lower half-bridge resonant converter, only one thyristor is conducted at any time T of the first bidirectional thyristor K1 and the second bidirectional thyristor K2, time division multiplexing control of the upper half-bridge resonant converter and the lower half-bridge resonant converter is achieved, the upper half-bridge resonant converter comprises a first switch tube S1, a second switch tube S2, a first resonant inductor L1, a first resonant capacitor C1, a first isolation transformer T1 and a first bidirectional thyristor K1, the drain electrode of the first switch tube S1 is connected to the positive electrode of a primary side first power supply E1, the source electrode of the first bidirectional thyristor K1 is sequentially connected with the primary side winding of the first isolation transformer T1, one end of the first bidirectional thyristor K1 is connected with the primary side of the first isolation transformer T1, the other end of the first bidirectional thyristor K1 is connected with the negative electrode of the first resonant inductor E1, and the other end of the first resonant capacitor E1 is connected with the negative electrode of the first switch tube E1.
2. The isolated high-frequency DC/DC converter according to claim 1, wherein the lower half-bridge resonant converter comprises a third switching tube S3 and a fourth switching tube S4, a second resonant inductor L2, a second resonant capacitor C2, a second isolation transformer T2 and a second triac K2, wherein the drain electrode of the second switching tube S2 is connected to the positive electrode of the primary side second power supply E2, the source electrode is sequentially connected to the second resonant inductor L2, the second resonant capacitor C2 and the primary side winding of the second isolation transformer T2, one end of the second triac K2 is connected to the primary side of the second isolation transformer T2, the other end is connected to the negative electrode of the second power supply E2, the drain electrode of the fourth switching tube S4 is connected to one end of the second resonant inductor L2, and the source electrode is connected to the negative electrode of the second power supply E2.
3. The isolated high-frequency DC/DC converter according to claim 1, wherein the secondary sides of the first and second isolation transformers T1 and T2 are connected in parallel and connected to an ac side of a rectifying circuit, the rectifying circuit adopts a diode bridge rectifying structure, two ends of the rectifying circuit are connected in parallel to an output capacitor Co and a load resistor R L , the output capacitor Co is a high-frequency low-ESR capacitor, and the load resistor R L is a variable resistor.
4. The isolated high frequency DC/DC converter of claim 1, wherein the upper half-bridge resonant converter and the lower half-bridge resonant converter are of heterogeneous design, have different circuit parameters, and are used for expanding the output voltage range of the converter, including parameters of model numbers of MOSFET devices, resonant inductance and resonant capacitance.
5. The isolated high frequency DC/DC converter of claim 1, wherein the primary sides of the first and second isolation transformers T1 and T2 are connected in series by a first triac K1 and a second triac K2, respectively.
6. The isolated high frequency DC/DC converter according to claim 1, wherein the first and second triac K1, K2 are provided with a current threshold I.
7. The isolated high-frequency DC/DC converter according to claim 1, wherein the first switching tube S1, the second switching tube S2, the third switching tube S3 and the fourth switching tube S4 are operated in a soft switching mode, and the resonance parameters are adjusted to perform zero-voltage on and zero-current off operation states.
8. The isolated high frequency DC/DC converter according to claim 1, wherein the first isolation transformer T1 and the second isolation transformer T2 are high frequency transformers.

Description

Isolated high-frequency DC/DC converter Technical Field The utility model relates to the technical field of power electronics, in particular to an isolated high-frequency DC/DC converter which is mainly used for improving the voltage gain of a high-frequency DC/DC converter system. Background With the rapid development of power electronics technology, high-frequency isolation type DC/DC converters are increasingly used in the fields of renewable energy sources, electric automobile charging stations, power supply of communication equipment, energy storage systems and the like. The performance of such converters has an important impact on the efficiency, power density and stability of the overall system. Among the numerous converter topologies, resonant DC/DC converters are becoming the dominant choice for engineering applications due to their inherent soft switching characteristics (zero voltage on ZVS and zero current off ZCS), high power density, and low electromagnetic interference (EMI). However, existing resonant converters still face some challenges in terms of topology design and operation performance, especially in terms of voltage gain range and efficiency optimization, and there are two main technical problems in that (1) the voltage gain range is limited, and the voltage gain of existing resonant converters, such as LLC resonant converters, is mainly determined by the resonance parameters and the operating frequency. Although a certain gain adjustment can be achieved by varying the switching frequency, the frequency variation can significantly affect the operating state of the resonant network, possibly leading to a failure of the soft switching characteristics. Meanwhile, when the load or input voltage is greatly changed, the efficiency of the conventional resonant converter in achieving wide voltage range adjustment is often significantly reduced. The limitation of the gain range greatly restricts the application capability of the resonant converter under complex working conditions, especially in the scene of needing to adjust output voltage in a large range, such as electric automobile fast charging equipment, distributed energy storage units and the like. (2) Efficiency drops over a wide voltage range-resonant converters can achieve higher efficiency around their resonant frequency, but when the gain requirement deviates from the design point, the operating frequency of the converter needs to be significantly shifted from the resonant frequency, resulting in increased switching losses and conduction losses, and thus reduced efficiency. In addition, the resonant converter with the traditional symmetrical design is difficult to simultaneously realize the efficient operation under the light load and heavy load working conditions in a wide voltage range. Particularly under heavy load conditions, the amplitude of the resonant current increases significantly, resulting in increased thermal stress on the lossy devices in the circuit, further reducing efficiency and system reliability. Therefore, a new topology is needed to ensure that the system maintains a high operating efficiency over a wide range while widening the voltage gain range. Disclosure of utility model The utility model relates to an isolated high-frequency DC/DC converter, which aims to solve the problems that the voltage gain range of the existing resonant converter is limited and the efficiency in a wide voltage range is difficult to guarantee. Through the topological structure of the designed upper half-bridge resonant converter and the lower half-bridge resonant converter, the expansion of the output voltage range of the converter is realized, and meanwhile, the reliability and the efficiency of the system operation are improved. The method mainly comprises the following steps: in order to achieve the above purpose, the technical scheme provided by the utility model is as follows: The isolation type high-frequency DC/DC converter comprises a primary circuit, a first isolation transformer T1, a second isolation transformer T2 and a rectifying circuit, and is characterized in that the primary circuit comprises an upper half-bridge resonant converter and a lower half-bridge resonant converter, only one thyristor is conducted at any time T of the first thyristor K1 and the second thyristor K2, and time division multiplexing control of the upper half-bridge resonant converter and the lower half-bridge resonant converter is achieved. Further, the upper half-bridge resonant converter comprises a first switch tube S1, a second switch tube S2, a first resonant inductor L1, a first resonant capacitor C1, a first isolation transformer T1 and a first bidirectional thyristor K1, wherein the drain electrode of the first switch tube S1 is connected to the positive electrode of a primary side first power supply E1, the source electrode is sequentially connected with the first resonant inductor L1, the first resonant capacitor C1 and the primary si