阅读说明：本技术 一种三电平软开关整流电路 (Three-level soft switching rectifying circuit ) 是由 王志东 赖熙庭 王绍煦 牛兴卓 于 2019-09-23 设计创作，主要内容包括：一种三电平软开关整流电路,用于实现整流电路的软开关,降低开关损耗,节约电路成本。该三电平软开关整流电路包括：两个开关管串联组成的开关桥臂、两个箝位二极管串联组成的开关管箝位电路、四个限流二极管串联组成的限流电路、交流输入电路以及直流输出接口；其中,开关桥臂与开关管箝位电路并联形成两个并联接口,两个并联接口分别连接限流电路两端形成闭环；交流输入电路的交流电源的一端连接储能电感的输入端另一端连接开关桥臂的中点；交流输入电路还包括换流电感及换流电容,换流电容的两端分别连接于开关桥臂的中点及限流电路的中点,储能电感的输出端连接开关管箝位电路的中点,换流电感连接于储能电感的输出端及限流电路的中点。(A three-level soft switching rectifying circuit is used for realizing soft switching of the rectifying circuit, reducing switching loss and saving circuit cost. The three-level soft switching rectifying circuit comprises: the circuit comprises a switch bridge arm formed by connecting two switch tubes in series, a switch tube clamping circuit formed by connecting two clamping diodes in series, a current limiting circuit formed by connecting four current limiting diodes in series, an alternating current input circuit and a direct current output interface; the switch bridge arm and the switch tube clamping circuit are connected in parallel to form two parallel connection ports, and the two parallel connection ports are respectively connected with two ends of the current limiting circuit to form a closed loop; one end of an alternating current power supply of the alternating current input circuit is connected with the input end of the energy storage inductor, and the other end of the alternating current power supply is connected with the middle point of the switch bridge arm; the alternating current input circuit further comprises a commutation inductor and a commutation capacitor, two ends of the commutation capacitor are respectively connected to the midpoint of the switch bridge arm and the midpoint of the current limiting circuit, the output end of the energy storage inductor is connected to the midpoint of the switch tube clamping circuit, and the commutation inductor is connected to the output end of the energy storage inductor and the midpoint of the current limiting circuit.)

1. A three-level soft-switching rectifier circuit, comprising:

the circuit comprises a switch bridge arm formed by connecting two switch tubes in series, a switch tube clamping circuit formed by connecting two clamping diodes in series, a current limiting circuit formed by connecting four current limiting diodes in series, an alternating current input circuit and a direct current output interface;

the switch bridge arm and the switch tube clamping circuit are connected in parallel to form two parallel connection ports, and the two parallel connection ports are respectively connected with two ends of the current limiting circuit to form a closed loop;

the current limiting circuit comprises an upper bridge arm and a lower bridge arm, each bridge arm comprises two current limiting diodes with opposite conduction directions, and the conduction directions of the two current limiting diodes at the connection part of the upper bridge arm and the lower bridge arm are the same;

the upper port of the direct current output interface is arranged at the midpoint of the upper bridge arm, and the lower port of the direct current output interface is arranged at the midpoint of the lower bridge arm;

one end of the alternating current input circuit is connected with the input end of the energy storage inductor, and the other end of the alternating current input circuit is connected with the middle point of the switch bridge arm;

the alternating current input circuit further comprises a commutation inductor and a commutation capacitor, two ends of the commutation capacitor are respectively connected to the midpoint of the switch bridge arm and the midpoint of the current limiting circuit, an output end of the energy storage inductor is connected to the midpoint of the switch tube clamping circuit, and the commutation inductor is connected to the output end of the energy storage inductor and the midpoint of the current limiting circuit.

2. The three-level soft switching rectifier circuit according to claim 1, wherein a voltage stabilizing circuit is connected between two ports of the DC output interface, the voltage stabilizing circuit is composed of two voltage dividing capacitors with the same capacitance value connected in series, and a middle point of the voltage stabilizing circuit is connected with a middle point of the switching bridge arm.

3. The three-level soft switching rectifier circuit according to claim 2, wherein a DC blocking capacitor is connected between the middle point of the voltage stabilizing circuit and the middle point of the switching bridge arm.

4. The three-level soft-switching rectifier circuit according to claim 3, wherein the capacitance value of the blocking capacitor is smaller than the capacitance value of the voltage dividing capacitor.

5. The three-level soft-switched rectifier circuit according to any of claims 1-4, wherein an inductance value of said energy storage inductor is greater than an inductance value of said commutation inductor.

6. The three-level soft-switched rectifier circuit according to any of claims 1 to 4, wherein the three-level soft-switched rectifier circuit is applied in parallel in a three-phase alternating current circuit.

Technical Field

The invention relates to the field of rectifier circuits, in particular to a three-level soft switching rectifier circuit.

Background

As shown in fig. 1, in a conventional three-level switching rectifier circuit, a positive half cycle of an alternating current outputs a high level through diodes D1 and D4, a zero level through a diode D1 and a switching tube Q1, a negative half cycle of the alternating current outputs a low level through diodes D2 and D3, and a zero level through a diode D2 and a switching tube Q2. According to the current loop of the circuit, when the circuit works, the on and off of the two switching tubes are hard switches, so that larger switching loss exists, and devices are easily damaged; secondly, when the circuit outputs high and low levels, two diodes D1 and D4 or diodes D2 and D3 are needed, so that the circuit has large conduction loss and is not beneficial to improving the working efficiency of the circuit.

In order to reduce the conduction loss of the diodes, a three-level rectifier circuit is also provided in the prior art, as shown in fig. 2, a high level is output only through one diode D1 in the positive half cycle of the alternating current, and a low level is output only through a diode D2 in the negative half cycle of the alternating current.

Disclosure of Invention

The embodiment of the invention provides a three-level soft switching rectifying circuit, which is used for realizing soft switching of the rectifying circuit, reducing switching loss and saving circuit cost.

The embodiment of the invention provides a three-level soft switching rectifying circuit, which is characterized by comprising the following components:

the circuit comprises a switch bridge arm formed by connecting two switch tubes in series, a switch tube clamping circuit formed by connecting two clamping diodes in series, a current limiting circuit formed by connecting four current limiting diodes in series, an alternating current input circuit and a direct current output interface;

the switch bridge arm and the switch tube clamping circuit are connected in parallel to form two parallel connection ports, and the two parallel connection ports are respectively connected with two ends of the current limiting circuit to form a closed loop;

the current limiting circuit comprises an upper bridge arm and a lower bridge arm, each bridge arm comprises two current limiting diodes with opposite conduction directions, and the conduction directions of the two current limiting diodes at the connection part of the upper bridge arm and the lower bridge arm are the same;

the upper port of the direct current output interface is arranged at the midpoint of the upper bridge arm, and the lower port of the direct current output interface is arranged at the midpoint of the lower bridge arm;

one end of the alternating current input circuit is connected with the input end of the energy storage inductor, and the other end of the alternating current input circuit is connected with the middle point of the switch bridge arm;

the alternating current input circuit further comprises a commutation inductor and a commutation capacitor, two ends of the commutation capacitor are respectively connected to the midpoint of the switch bridge arm and the midpoint of the current limiting circuit, the output end of the energy storage inductor is connected to the midpoint of the switch tube clamping circuit, and the commutation inductor is connected to the output end of the energy storage inductor and the midpoint of the current limiting circuit.

Optionally, as a possible implementation manner, in the three-level soft-switching rectifying circuit in the embodiment of the present invention, a voltage stabilizing circuit is connected between two ports of the dc output interface, the voltage stabilizing circuit is formed by connecting two voltage dividing capacitors with the same capacitance in series, and a midpoint of the voltage stabilizing circuit is connected to a midpoint of the switch bridge arm.

Optionally, as a possible implementation manner, in the three-level soft-switching rectifier circuit in the embodiment of the present invention, a dc blocking capacitor is connected between a midpoint of the voltage stabilizing circuit and a midpoint of the switching bridge arm.

Optionally, as a possible implementation manner, in the three-level soft-switching rectifying circuit in the embodiment of the present invention, a capacitance value of the blocking capacitor is smaller than a capacitance value of the voltage dividing capacitor.

Optionally, as a possible implementation manner, in the three-level soft-switching rectifying circuit in the embodiment of the present invention, an inductance value of the energy storage inductor is greater than an inductance value of the commutation inductor.

Optionally, as a possible implementation manner, the three-level soft switching rectifying circuit in the embodiment of the present invention is applied to a three-phase ac circuit in parallel.

According to the technical scheme, the embodiment of the invention has the following advantages:

the three-level soft switching rectifying circuit provided by the embodiment of the invention is provided with the current converting inductor and the current converting capacitor, so that the switching voltage at two ends of the current limiting diode can be adjusted, the zero-current switching of the rectifying output circuit is realized, the switching loss is reduced, and the efficiency of electric energy conversion is improved.

Drawings

FIG. 1 is a schematic diagram of a three-level rectifier circuit in the prior art;

FIG. 2 is a schematic diagram of an embodiment of another three-level soft-switched rectifier circuit in the prior art;

FIG. 3 is a schematic diagram of an embodiment of a three-level soft-switching rectifier circuit according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a current conducting direction of a three-level soft-switching rectifier circuit in a first energy storage stage according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a current conducting direction of a three-level soft-switching rectifier circuit in a second energy storage stage according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of a current conducting direction of a three-level soft-switching rectifying circuit in a power supply stage according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of the current conducting direction of the three-level soft-switching rectifying circuit in the discharging stage according to the embodiment of the present invention;

FIG. 8 is a schematic diagram of another embodiment of a three-level soft-switching rectifier circuit according to an embodiment of the present invention;

fig. 9 is a schematic diagram of another embodiment of a three-level soft-switching rectifier circuit according to an embodiment of the present invention.

Detailed Description

A three-level soft switching rectifying circuit is used for realizing soft switching of the rectifying circuit, reducing switching loss and saving circuit cost. In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.