WO2018036315A1

WO2018036315A1 - Resonant converter and current processing method

Info

Publication number: WO2018036315A1
Application number: PCT/CN2017/093717
Authority: WO
Inventors: 李丹
Original assignee: 中兴通讯股份有限公司
Priority date: 2016-08-23
Filing date: 2017-07-20
Publication date: 2018-03-01
Also published as: CN107769565A

Abstract

A resonant converter and a current processing method. The resonant converter comprises two or more resonant units. Each of the resonant units comprises: a bridge inverter circuit, a resonant circuit, a transformer, a rectification circuit, and a filter circuit. An input terminal of the bridge inverter circuit is connected to an input terminal of a direct current (DC) voltage source. An output terminal of the bridge inverter circuit is connected to an input terminal of the resonant circuit. An output terminal of the resonant circuit is connected to a first input terminal at a primary side of the transformer. An output terminal at a secondary side of the transformer is connected to an input terminal of the rectification circuit. An output terminal of the rectification circuit is connected to the filter circuit. Secondary input terminals at primary sides of transformers of the two or more resonant units are connected to one another and according to a triangular configuration or a star configuration. The connection points at the primary sides of the transformers in the two or more resonant units are suspended in the air. Therefore, the converter does not need to employ a complex control method to overcome a problem of uneven current flows in a resonant converter in the related art.

Description

Resonant converter and current processing method

Technical field

The present invention relates to the field of communications, and in particular to a resonant converter and a current processing method.

Background technique

Resonant converters are more and more widely used in DC-DC converter circuits due to their high efficiency and high power density, especially multi-phase interleaved resonant converters, which inherit the high efficiency advantages of single-phase resonant converters. Moreover, the ripple current is effectively reduced, and the problem that the filter capacitor is too large and the volume is too large when the resonant converter is applied in medium and large power applications is solved.

1 is a multiphase resonant converter in the related art. As shown in FIG. 1, the circuit of the conventional multiphase interleaved resonant converter generally has an input terminal and an output terminal connected in parallel, and the switching transistor driving signals of the phase circuits are staggered. At a certain angle, the ripple currents between the different phases cancel each other, thereby reducing the output current ripple. However, due to the discreteness of magnetic devices and the like, the parameters of each phase circuit cannot be guaranteed to be completely consistent. Therefore, the method of directly connecting the input terminal and the output terminal directly requires a more complicated control method to ensure the current sharing between the phase circuits. Power balance.

Summary of the invention

The embodiment of the invention provides a resonant converter and a current processing method, so as to at least solve the direct parallel connection between the input end and the output end of the resonant converter in the related art, which leads to the need to adopt a more complicated control method to ensure the average between the phase circuits. Flow and power balance issues.

According to an embodiment of the present invention, there is provided a resonant converter comprising: two or more resonant units, each resonant unit comprising: a bridge inverter circuit, a resonant circuit, a transformer, a rectifier circuit, a filter circuit; The input end of the inverter circuit is connected to the input end of the DC voltage, the output end of the bridge inverter circuit is connected to the input end of the resonant circuit, and the output end of the resonant circuit is first with the primary side of the transformer The input end is connected, the first output end of the secondary side of the transformer is connected to the input end of the rectifier circuit, the output end of the rectifier circuit and the filter circuit Connected, the second input end of the primary side of the transformer of the two or more resonant units is a polygonal connection or a star connection, and the primary sides of the transformers of the two or more resonant units are suspended.

Optionally, the resonant converter further includes: a second output end of the transformer secondary side of the two or more resonant units is a star connection, and a connection point of the star connection is connected to a midpoint of the filter circuit, wherein The midpoint of the filter circuit is a series connection point of two sets of capacitors in the filter circuit.

Optionally, the bridge inverter circuit comprises a half bridge inverter circuit and a full bridge inverter circuit.

Optionally, in the case that the bridge inverter circuit is a half bridge inverter circuit, the bridge inverter circuit includes two first switch tubes; and the bridge inverter circuit is a full bridge inverter circuit. In the case, the bridge inverter circuit includes four first switching tubes, wherein the first switching tube includes one of the following: a bidirectional controllable metal oxide semiconductor field effect transistor, which can turn off the thyristor.

Optionally, the resonant circuit includes a resonant inductor and a resonant capacitor.

Optionally, the resonant circuit is a series resonance, a parallel resonance, a series-parallel resonance or an LLC series resonance.

Optionally, the rectifier circuit is a full-wave rectifier circuit, including two second switch tubes.

Optionally, the second switching transistor comprises one of the following: a metal oxide field effect transistor, a bidirectional controllable metal oxide semiconductor field effect transistor, an insulated gate bipolar transistor, a turn-off thyristor, and a diode.

According to another embodiment of the present invention, a current processing method is provided, comprising: a polygonal connection or a star connection between two ends of a transformer primary side of two or more resonance units of a resonant converter and the two The primary connection points of the transformers of the above resonant units are in a suspended state, such that the current amplitudes of the primary sides of the transformers of the two or more resonant units are equal, wherein the two or more resonant units are staggered by a predetermined angle.

In an embodiment of the present invention, a computer storage medium is further provided, and the computer storage medium may store an execution instruction for performing the implementation of the current processing method in the above embodiment.

According to an embodiment of the invention, the second input of the primary side of the transformer due to more than two resonant units The end is a polygonal connection or a star connection, and the primary side of the transformer of the two or more resonance units is in a floating state, and the current amplitudes of the primary sides of the transformers of the two or more resonance units can be made equal regardless of whether the circuit parameters of the respective phases are consistent. That is, the problem of poor current sharing of the resonant converter in the related art can be overcome without using a more complicated control method. Therefore, the direct connection between the input end and the output end of the resonant converter in the related art can be solved, which leads to the need to adopt a more complicated control method to ensure the current sharing and power balance between the phase circuits, so as to ensure efficiency and power density. At the same time, it is possible to achieve current sharing and power balance between phases, simplifying the control method.

DRAWINGS

The drawings described herein are intended to provide a further understanding of the invention, and are intended to be a part of the invention. In the drawing:

1 is a multiphase resonant converter in the related art;

2 is a schematic structural view of a resonant converter according to an embodiment of the present invention;

3 is a first schematic structural view of a resonant converter according to an embodiment of the present invention;

4 is a second schematic structural view of a resonant converter according to an embodiment of the present invention;

FIG. 5 is a third schematic structural diagram of a resonant converter according to an embodiment of the present invention; FIG.

6 is a flow chart of a current processing method in accordance with an embodiment of the present invention.

detailed description

The invention will be described in detail below with reference to the drawings in conjunction with the embodiments. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict.

It is to be understood that the terms "first", "second" and the like in the specification and claims of the present invention are used to distinguish similar objects, and are not necessarily used to describe a particular order or order.

Example 1

In this embodiment, a resonant converter is provided, which is composed of two or two The upper resonance unit is composed, and the driving signals between the respective resonance units are shifted by a certain angle to achieve the effect of reducing the ripple current. The resonant converter is not only highly efficient, but also achieves current sharing and power balance between the various resonant units.

2 is a schematic structural diagram of a resonant converter according to an embodiment of the present invention. As shown in FIG. 2, the resonant converter includes two or more resonant units, each of which includes: a bridge inverter circuit, a resonant circuit, a transformer, The rectifier circuit and the filter circuit; the input end of the bridge inverter circuit is connected to the input end of the DC voltage, and the output end of the bridge inverter circuit is connected to the input end of the resonance circuit (for example, the ends of the bridge inverter circuit of each resonance unit are The input voltage is connected, and the upper and lower switch tubes are connected in series, and the middle points of the two switch tubes are connected to the input end of the resonant circuit), the output end of the resonant circuit is connected to the first input end of the primary side of the transformer, and the first output end of the secondary side of the transformer Connected to the input end of the rectifier circuit, the output end of the rectifier circuit is connected to the filter circuit, and the second input end of the transformer primary side of the two or more resonance units is a polygonal connection or a star connection, and two or more resonance units are The primary connection point of the transformer is floating.

Through the above steps, since the second input end of the primary side of the transformer of the two or more resonant units is a polygonal connection or a star connection, and the primary side of the transformer of the two or more resonant units is in a floating state, it is not necessary to consider whether the parameters of the respective phase circuits are consistent. The current amplitudes of the primary sides of the transformers of two or more resonant units can be made equal, that is, the problem of poor current sharing of the resonant converters in the related art can be overcome without using a more complicated control method. Therefore, the direct connection between the input end and the output end of the resonant converter in the related art can be solved, which leads to the need to adopt a more complicated control method to ensure the current sharing and power balance between the phase circuits, so as to ensure efficiency and power density. At the same time, the current sharing and power balance between the phases can be realized, and the control mode is simplified;

Optionally, the resonant converter further includes: a second output end of the transformer secondary side of the two or more resonant units is a star connection, and a connection point of the star connection is connected to a midpoint of the filter circuit, wherein The midpoint of the filter circuit is the series connection point of the two sets of capacitors in the filter circuit. Through the above steps, the star connection point of the second output end of the transformer secondary side is stable and has no jump, so that its electromagnetic compatibility (Electro Magnetic Compatibility, referred to as EMC) works well.

For example, FIG. 3 is a first schematic diagram of a preferred structure of a resonant converter according to an embodiment of the present invention. As shown in FIG. 3, the resonant converter includes a resonant transform unit, and the resonant transform unit includes a bridge inverter circuit, a resonant circuit, a transformer, a rectifier circuit, and a filter circuit. Wherein, the two ends of the bridge inverter circuit are connected with the input voltage, and the upper and lower two switch tubes are connected in series, and the midpoints of the two switch tubes are connected with the input end of the resonant circuit, and the output end of the resonant circuit is connected with the first input end of the transformer, and the transformer is An output end is connected to the input end of the rectifier circuit, and the rectifier circuit is composed of two upper and lower switch tubes, and the two ends of the rectifier circuit are respectively connected in parallel with the output filter circuit.

Optionally, the bridge inverter circuit includes a half bridge inverter circuit and a full bridge inverter circuit.

Optionally, in the case that the bridge inverter circuit is a half bridge inverter circuit, the bridge inverter circuit includes two first switch tubes, and the positions are respectively located in the upper tube and the lower tube of the bridge arm of the bridge inverter circuit. When the bridge inverter circuit is full-bridge inverter power, the bridge inverter circuit includes four first switch tubes, and the positions are respectively located on the super forearm upper tube, the super forearm lower tube, and the lag arm of the bridge inverter circuit. Upper tube, lagging arm lower tube. Wherein, the first switching tube comprises one of the following: a bidirectional controllable metal oxide semiconductor field effect transistor, which can turn off the thyristor.

Optionally, the resonant circuit described above includes a resonant inductor and a resonant capacitor.

Optionally, the rectifier circuit is a full-wave rectifier circuit, and includes two second switch tubes.

Optionally, the second switch tube comprises one of the following: a metal oxide field effect transistor, a bidirectional controllable metal oxide semiconductor field effect transistor, an insulated gate bipolar transistor, a turn-off thyristor, and a diode.

In order to facilitate the understanding of the above embodiments, the embodiment of the present invention is described by taking a resonant converter including three resonant units as an example. FIG. 4 is a schematic structural diagram 2 of a resonant converter according to an embodiment of the present invention, as shown in FIG. The resonant converter in the embodiment is composed of three resonant conversion units connected in parallel, three units are respectively connected to two ends of the input voltage, and the primary side of the transformer of the resonant converter is connected and suspended by the second input end of each unit transformer. The transformer secondary side of the resonant converter is star-connected through the second output of each unit transformer and connects the star connection point to the midpoint of the output filter circuit.

The driving signals between the three bridge arms of the primary side of the transformer are staggered by 120 degrees, and the upper and lower tube driving signals of the same bridge arm are staggered by 180 degrees, and the duty ratio of each switching tube does not exceed 50%.

The embodiment of the invention reduces the current ripple by using the three-phase parallel resonance conversion technology, thereby reducing the volume of the output filter capacitor and improving the power density of the power source. Moreover, the primary side of the transformer adopts a star connection mode, which ensures a good current sharing between the resonance conversion units.

FIG. 5 is a third schematic structural diagram of a resonant converter according to an embodiment of the present invention. As shown in FIG. 5, the resonant converter in this embodiment is composed of three resonant conversion units connected in parallel, and three units are respectively connected to the input voltage. The primary side of the transformer of the resonant converter is triangulated and suspended by the second input of each unit transformer, and the secondary side of the transformer of the resonant converter is connected by a star of the second output of each unit transformer, and the star is connected The type connection point is connected to the midpoint of the output filter circuit.

The driving signals between the three bridge arms of the primary side are staggered by 120 degrees, and the upper and lower tube driving signals of the same bridge arm are staggered by 180 degrees, and the duty ratio of each switching tube does not exceed 50%.

The embodiment of the invention reduces the current ripple by using the three-phase parallel resonance conversion technology, thereby reducing the volume of the output filter capacitor and improving the power density of the power source. And the primary side of the transformer adopts a triangular connection mode to ensure good current sharing and power balance between the various resonance conversion units.

Example 2

A current processing method is also provided in this embodiment. FIG. 6 is a flowchart of a current processing method according to an embodiment of the present invention. As shown in FIG. 6, the method includes:

Step S602, a mode in which a primary connection or a star connection is connected between the second input ends of the transformer primary sides of the two or more resonance units of the resonant converter, and a primary connection point of the transformers of the two or more resonance units is in a floating state. The current amplitudes of the primary sides of the transformers of the two or more resonant units are equal, wherein two or more resonant units are staggered by a predetermined angle.

Through the above steps, since the second input end of the primary side of the transformer of the two or more resonant units is a triangular connection or a star connection, and the primary side of the transformer of the two or more resonant units is in a floating state, it is not necessary to consider whether the parameters of the phase circuits are consistent. The current amplitudes of the primary sides of the transformers of two or more resonant units can be made equal, that is, the resonance in the related art can be overcome without using a complicated control method. The problem of poor current sharing in the converter. Therefore, the direct connection between the input end and the output end of the resonant converter in the related art can be solved, which leads to the need to adopt a more complicated control method to ensure the current sharing and power balance between the phase circuits, so as to ensure efficiency and power density. At the same time, it is possible to achieve current sharing and power balance between phases, simplifying the control method.

It will be apparent to those skilled in the art that the various modules or steps of the present invention described above can be implemented by a general-purpose computing device that can be centralized on a single computing device or distributed across a network of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device such that they may be stored in the storage device by the computing device and, in some cases, may be different from the order herein. The steps shown or described are performed, or they are separately fabricated into individual integrated circuit modules, or a plurality of modules or steps thereof are fabricated as a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software.

The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Industrial applicability

The above technical solution provided by the embodiments of the present invention can be applied to a current processing process, in which a second input end of a transformer primary side of two or more resonant units is a polygonal connection or a star connection, and a transformer of two or more resonance units If the primary side is in a floating state, it is possible to make the current amplitudes of the primary sides of the transformers of two or more resonant units equal, regardless of whether the circuit parameters of the respective phases are consistent, that is, the resonant converter of the related art can be overcome without using a complicated control method. Poor current sharing problem. Therefore, the direct connection between the input end and the output end of the resonant converter in the related art can be solved, which leads to the need to adopt a more complicated control method to ensure the current sharing and power balance between the phase circuits, so as to ensure efficiency and power density. At the same time, it is possible to achieve current sharing and power balance between phases, simplifying the control method.

Claims

A resonant converter comprising two or more resonant units, each resonant unit comprising: a bridge inverter circuit, a resonant circuit, a transformer, a rectifier circuit, a filter circuit; an input end of the bridge inverter circuit and a DC voltage The input end is connected, the output end of the bridge inverter circuit is connected to the input end of the resonant circuit, and the output end of the resonant circuit is connected to the first input end of the primary side of the transformer, and the second side of the transformer An output end is connected to the input end of the rectifier circuit, and an output end of the rectifier circuit is connected to the filter circuit.

A second type of connection between the second input ends of the transformers of the two or more resonant units is a polygonal connection or a star connection, and the primary connection points of the transformers of the two or more resonance units are suspended.
The resonant converter according to claim 1, further comprising: a second output end of the transformer secondary side of said two or more resonant units being a star connection, and a star connection connection point and said filter circuit The points are connected, wherein the midpoint of the filter circuit is a series connection point of two sets of capacitors in the filter circuit.
The resonant converter of claim 1 wherein said bridge inverter circuit comprises a half bridge inverter circuit and a full bridge inverter circuit.
The resonant converter according to claim 3, wherein, in the case where the bridge inverter circuit is a half bridge inverter circuit, the bridge inverter circuit includes two first switching tubes; In the case where the variable circuit is a full-bridge inverter, the bridge inverter circuit includes four first switching tubes, wherein the first switching tube includes one of the following: a bidirectional controllable metal oxide semiconductor field effect transistor The thyristor can be turned off.
The resonant converter of claim 1 wherein said resonant circuit comprises a resonant inductor and a resonant capacitor.
A resonant converter according to claim 5, wherein said resonant circuit is a series resonance, a parallel resonance, a series-parallel resonance or an LLC series resonance.
The resonant converter of claim 1 wherein said rectifier circuit is a full wave rectifier circuit comprising two second switching transistors.
The resonant converter of claim 7 wherein said second switching transistor comprises one of: a metal oxide field effect transistor, a bidirectionally controllable metal oxide semiconductor field effect transistor, an insulated gate bipolar transistor, Broken thyristor, diode.
A current processing method comprising:

Passing through a polygonal connection or a star connection between the second input ends of the transformer primary sides of the two or more resonance units of the resonant converter, and the transformer primary connection points of the two or more resonance units are suspended. The current amplitudes of the primary sides of the transformers of the two or more resonant units are equal, wherein the two or more resonant units are staggered by a predetermined angle.