CN-121984357-A - Series resonant converter, control method, equipment and medium

CN121984357ACN 121984357 ACN121984357 ACN 121984357ACN-121984357-A

Abstract

The invention discloses a series resonant converter, a control method, equipment and a medium, wherein the converter comprises a power supply, a switching circuit, a channel one resonant circuit, a channel two resonant circuit and a rectifying circuit, a first transformer and a second transformer are connected with a first input capacitor and a second input capacitor, the other end of a primary side of the first transformer and the other end of the primary side of the second transformer are connected with a first switching tube and a second switching tube, and a secondary side of the first transformer and a secondary side of the second transformer are respectively connected with the rectifying circuit so as to control the output of the rectifying circuit. The invention can control the on and off of the switching circuit, combine the adjustment of the switching frequency, enable the current of the double-channel resonant circuit to be overlapped to form inductive total current, drive the switching circuit to realize soft switching, and finally realize the control of the secondary side working state of the transformer and the output of wide range voltage.

Inventors

REN JIE
BAI BING
ZHANG XIAOJUN
ZHANG CHENG
Zou Minyang
DAI JIALONG
SHU ZELIANG

Assignees

神华神东电力有限责任公司
神华神东电力有限责任公司新能源分公司

Dates

Publication Date: 20260505
Application Date: 20260113

Claims (10)

1. A series resonant converter, comprising: the switching device comprises a power supply, a switching circuit, a channel one resonant circuit, a channel two resonant circuit and a rectifying circuit; The switching circuit comprises a first switching tube, a second switching tube, a first input capacitor and a second input capacitor, wherein the drain electrode of the first switching tube is connected with the positive electrode of the power supply, one end of the first input capacitor, and the source electrode of the first switching tube is connected with the drain electrode of the second switching tube; the channel one resonant circuit comprises a first resonant inductor, a first resonant capacitor and a first transformer, the channel two resonant circuit comprises a second resonant inductor, a second resonant capacitor and a second transformer, one end of a primary side of the first transformer and one end of a primary side of the second transformer are connected with the other end of the first input capacitor and one end of the second input capacitor, the other end of the primary side of the first transformer and the other end of the primary side of the second transformer are connected with a source electrode of a first switching tube and a drain electrode of the second switching tube, and a secondary side of the first transformer and a secondary side of the second transformer are respectively connected with the input of the rectifying circuit so as to control the output of the rectifying circuit.
2. The series resonant converter of claim 1, wherein one end of the first resonant inductor is connected to the other end of the first input capacitor, one end of the second resonant inductor, and the other end of the first resonant inductor is connected to one end of the first exciting inductor of the first transformer, the other end of the first exciting inductor of the first transformer is connected to one end of the second exciting inductor of the second transformer, the other end of the second exciting inductor is connected to one end of the second resonant capacitor, and the other end of the second resonant capacitor is connected to the other end of the second resonant inductor.
3. The series resonant converter of claim 1, wherein the rectifying circuit comprises a first rectifying circuit and a second rectifying circuit, and wherein the first rectifying circuit and the second rectifying circuit are full-bridge rectifying circuits.
4. A series resonant converter as claimed in claim 1 wherein the duty cycle of the drive signal of the first switching tube is n and the duty cycle of the drive signal of the second switching tube is 1-n, thereby achieving duty cycle complementary conduction.
5. The series resonant converter of claim 1 wherein the first resonant circuit is configured to provide an inductive current when in operation in an inductive region, and wherein the resonant current provided by the second resonant circuit is summed with the resonant current of the first resonant circuit when in operation in the inductive or capacitive region to provide a current through the first switching tube and the second switching tube, the current through the first switching tube and the second switching tube being an inductive current, thereby ensuring that the first switching tube and the second switching tube achieve zero voltage turn-on.
6. The series resonant converter of claim 1, wherein the rectifying circuit comprises a first rectifying circuit and a second rectifying circuit, wherein the first rectifying circuit is a full-bridge rectifying circuit, and the second rectifying circuit is a full-wave rectifying circuit.
7. A control method is characterized in that the control method is applied to the series resonant converter as claimed in any one of claims 1 to 6, and comprises the steps that a channel-one resonant circuit works in an inductive area to provide inductive current, and the resonant current provided by a channel-two resonant circuit works in the inductive or capacitive area is added with the resonant current of the channel-one resonant circuit to obtain currents passing through a first switching tube and a second switching tube, wherein the currents passing through the first switching tube and the second switching tube are inductive currents, so that zero-voltage opening of the first switching tube and the second switching tube is ensured.
8. The control method according to claim 7, wherein the rectifying circuit includes a first rectifying circuit, a second rectifying circuit; The first rectifying circuit is a full-bridge rectifying circuit, and the second rectifying circuit comprises a full-wave rectifying circuit or a full-bridge rectifying circuit; the method comprises the steps of switching the second rectifying circuit into a full-wave rectifying circuit if the impedance value of an output load connected with the rectifying circuit is smaller than a preset load impedance threshold value, and switching the second rectifying circuit into a full-bridge rectifying circuit if not.
9. An electronic device comprising the series resonant converter according to any one of claims 1 to 6.
10. A storage medium having stored thereon computer-executable instructions, the computer executable instructions are for performing the method of any one of claims 7 to 8.

Description

Series resonant converter, control method, equipment and medium Technical Field The present invention relates to the field of electronic circuits, and in particular, to a series resonant converter, a control method, a device, and a medium. Background With the rapid development of power electronics technology, in the field of medium and high power direct current, such as applications of medium voltage direct current power grids, aviation power supplies, communication power supplies, server power supplies, electric car charging and lighting power supplies, the requirements of converter efficiency and power density become higher and higher, so that the related direct current converters have developed trend characterized by miniaturization, high efficiency, low ripple, low electromagnetic interference, good dynamic performance and high reliability. In order to reduce the switching loss of the converter and improve the working efficiency, a technology of realizing high-frequency soft switching by a switching tube and a corresponding series of converter structures are proposed. The technology enables the terminal voltage of the device or the current flowing through the device to be close to zero when the power device performs switching action, and the switching loss of the converter is greatly reduced, so that the switching frequency is improved, and the capacity and the volume of the magnetic element required by the system are reduced. Resonant converters based on high frequency soft switching technology have begun to be widely accepted and used in the last century. These converters can operate in high frequency soft switching mode without additional control strategies, with significant advantages in reducing switching losses and increasing power density. Among a series of resonant converter structures, a series resonant converter based on Pulse Frequency Modulation (PFM) control (i.e., an LLC resonant converter) is considered to be one of the isolated DC-DC converters that exhibits a prominence. In order for a conventional LLC topology to achieve a wide output voltage range, a smaller magnetizing inductance and a wide switching frequency range are required. A smaller excitation inductance results in larger circulating current and conduction losses, while a wide switching frequency may cause the LLC resonant converter to enter the capacitive region, further losing the zero current turn off (ZCS) capability, in addition to making the design of the magnetic device difficult. Therefore, how to compress the switching frequency range under the premise of using a moderate excitation inductance to achieve higher overall efficiency of the LLC under the voltage range is a problem to be solved. Disclosure of Invention The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, the invention provides the series resonant converter, which can combine the control of the on-off of the switching circuit and the adjustment of the switching frequency, so that the current of the two-channel resonant circuit is superposed to form inductive total current, the switching circuit is driven to realize soft switching, and finally, the secondary side working state control and the wide-range voltage output of the transformer are realized. The invention also provides equipment with the series resonant converter, a control method using the series resonant converter and a medium thereof. According to an embodiment of the first aspect of the present invention, a series resonant converter includes: the switching device comprises a power supply, a switching circuit, a channel one resonant circuit, a channel two resonant circuit and a rectifying circuit; The switching circuit comprises a first switching tube, a second switching tube, a first input capacitor and a second input capacitor, wherein the drain electrode of the first switching tube is connected with the positive electrode of the power supply, one end of the first input capacitor, and the source electrode of the first switching tube is connected with the drain electrode of the second switching tube; the channel one resonant circuit comprises a first resonant inductor, a first resonant capacitor and a first transformer, the channel two resonant circuit comprises a second resonant inductor, a second resonant capacitor and a second transformer, one end of a primary side of the first transformer and one end of a primary side of the second transformer are connected with the other end of the first input capacitor and one end of the second input capacitor, the other end of the primary side of the first transformer and the other end of the primary side of the second transformer are connected with a source electrode of a first switching tube and a drain electrode of the second switching tube, and a secondary side of the first transformer and a secondary side of the second transformer are respectively connected with the input of the rectifying c