阅读说明：本技术 一种使用低复杂度电力电子变压器的串联型12脉波整流器 (Series 12-pulse rectifier using low-complexity power electronic transformer ) 是由 孟凡刚 贺洪波 高蕾 于 2020-08-06 设计创作，主要内容包括：本发明提供了一种使用低复杂度电力电子变压器的串联型12脉波整流器,属于电力电子技术领域。该串联型12脉波整流器电力电子变换器与中高频移相变压器共同组成电力电子变压器。电力电子变换器包括两组三相二极管整流桥、开关管、二极管、钳位电路和控制电路。电力电子变换器由控制电路控制两个开关管通断,对输入的交流电进行升频,中高频变压器主要用来移相与隔离,两组三相全桥整流电路串联连接,输出电压加倍,直流侧采用大电容滤波。本发明所述基于低复杂度电力电子变压器的串联型12脉波整流器,减小了移相变压器的体积,减轻了其重量,且电力电子变换器的结构简单,无源器件少,可靠性高,效果稳定。本发明适应于中高频大功率整流场合。(The invention provides a series 12-pulse rectifier using a low-complexity power electronic transformer, and belongs to the technical field of power electronics. The power electronic converter of the series 12-pulse rectifier and the medium-high frequency phase-shifting transformer jointly form a power electronic transformer. The power electronic converter comprises two groups of three-phase diode rectifier bridges, a switching tube, diodes, a clamping circuit and a control circuit. The power electronic converter controls the on-off of the two switching tubes by the control circuit to boost the input alternating current, the medium-high frequency transformer is mainly used for phase shifting and isolation, the two groups of three-phase full-bridge rectifying circuits are connected in series, the output voltage is doubled, and the direct current side adopts large-capacitance filtering. The series 12-pulse rectifier based on the low-complexity power electronic transformer reduces the volume and the weight of the phase-shifting transformer, and the power electronic transformer is simple in structure, few in passive devices, high in reliability and stable in effect. The invention is suitable for medium-high frequency high-power rectification occasions.)

1. A series 12-pulse rectifier using low complexity power electronic transformer, characterized in that itThe method comprises the following steps: the power supply comprises an input inductor (1), a power electronic converter (2), a medium-high frequency phase-shifting transformer (3), a first group of three-phase full-bridge rectifying circuits (4), a second group of three-phase full-bridge rectifying circuits (5), a first direct-current side capacitor (6), a second direct-current side capacitor (7), a load (8) and a PWM control circuit (9); the power electronic converter (2) and the medium-high frequency phase-shifting transformer (3) jointly form a power electronic transformer; the left end of the input inductor (1) is respectively connected with a three-phase voltage source, and the right end of the input inductor (1) is respectively connected with the central point of each phase primary side double winding of the medium-high frequency phase-shifting transformer (3); the synonym ends of two groups of windings of the medium-high frequency phase-shifting transformer (3) are respectively connected with two groups of three-phase rectifier bridges of the power electronic converter (2); the on-off of two switching tubes of the power electronic converter (2) is controlled by a control signal of a PWM control circuit (9); two secondary windings of the medium-high frequency phase-shifting transformer (3) are respectively connected in a star shape and an angle shape, and the two secondary windings of the medium-high frequency phase-shifting transformer (3) output two groups of three-phase voltages with the phase difference of 30 degrees; the input end of a first group of three-phase full-bridge rectifying circuits (4) and the output end a of a medium-high frequency phase-shifting transformer (3)₁、b₁、c₁The input end of a second group of three-phase full-bridge rectifying circuits (5) is connected with the output end a of the medium-high frequency phase-shifting transformer (3)₂、b₂、c₂Connecting; the first group of three-phase full-bridge rectification circuits (4) and the second group of three-phase full-bridge rectification circuits (5) are connected in series, and output voltage is doubled; the first direct current side capacitor (6) is connected with the second direct current side capacitor (7) in series; the first group of three-phase full-bridge rectification circuits (4) and the second group of three-phase full-bridge rectification circuits (5) are connected in parallel with the first direct-current side capacitor (6), the second direct-current side capacitor (7) and the load (8).

2. The series 12-pulse rectifier of claim 1, wherein: input inductance L_s(1) The total inductance of the rectifier including the leakage inductance of the high-frequency transformer is respectively connected with a three-phase alternating current voltage source u_sa、u_sb、u_scAre connected in series.

3. A method according to claim 1A series 12-pulse rectifier using a low-complexity power electronic transformer, comprising: the power electronic transformer is formed by the power electronic transformer (2) and the medium-high frequency phase-shifting transformer (3), the power electronic transformer (2) is formed by a three-phase diode rectifier bridge, a switching tube, a diode and a clamping circuit, the phase difference of two groups of windings on the primary side of the medium-high frequency phase-shifting transformer (3) is 180 degrees, the first group of windings is connected with the three-phase diode rectifier bridge Rec3, and the second group of windings is connected with the three-phase diode rectifier bridge Rec 4; the rectifier bridges Rec3 and Rec4 are respectively connected with the switch tube S₁And S₂Connected in parallel via a diode D₁、D₂And D₃、D₄Sharing a clamp circuit.

4. The series 12-pulse rectifier of claim 1, wherein: the control circuit consists of a voltage phase sampling circuit, a control signal generating circuit and a drive circuit, wherein the sampling circuit is used for sampling voltage u_saSampling the phase, and sending the collected phase information to a control signal generating circuit; the PWM control circuit (9) uses a high-frequency square wave signal with the duty ratio of 0.5 to control a switch tube S₁And S₂The input power frequency alternating current is converted into high-frequency alternating current by the on-off of the switch.

5. The series 12-pulse rectifier of claim 1, further comprising: the medium-high frequency phase-shifting transformer (3) adopts an isolated transformer structure, the medium-high frequency phase-shifting transformer (3) is composed of 3 core columns, each core column is provided with 2 primary windings and 2 secondary windings, and the turn ratio of two groups of windings on the primary side of the high-frequency transformer (3) meets N₁:N₂The phase difference is 180 degrees, 2 windings on the secondary side are respectively connected in a star shape and an angle shape, the turn ratio of the windings connected in the star shape to the windings connected in the angle shape is 1:1.73, and the amplitudes of two groups of three-phase voltages output by the secondary side winding of the power electronic transformer (2) are equal; the star-connected winding has the same voltage phase as the primary winding, and the angle-connected winding has a phase difference of 30 DEG from the primary winding。

6. The series 12-pulse rectifier of claim 1, further comprising: the first group of three-phase full-bridge rectification circuits (4) and the second group of three-phase full-bridge rectification circuits (5) are connected in series, and output voltage is doubled; the first direct current side capacitor (6) and the second direct current side capacitor (7) adopt large-capacitor filtering.

Technical Field

The invention relates to a series 12-pulse rectifier using a low-complexity power electronic transformer, and belongs to the technical field of power electronics.

Background

The multi-pulse rectifier has high reliability and strong stability, and is mainly applied to high-power occasions such as electrolysis, electroplating, power systems and the like. The phase-shifting transformer is a necessary device of a multi-pulse rectification circuit and mainly used for providing a plurality of groups of three-phase voltages with phase differences for a rectification bridge. However, the application occasions of the multi-pulse-wave rectifier are severely limited by the problems that the phase-shifting transformer is large in size, heavy in weight, low in power density and the like of the multi-pulse-wave rectifier. Therefore, the power electronic transformer is applied to the multi-pulse rectifier circuit, and the problems of large size, heavy weight and the like of the phase-shifting transformer are solved, but a power electronic converter in the power electronic transformer is high in complexity and difficult to control, and the application occasions of the multi-pulse rectifier are limited in a fixed range. Therefore, the low-complexity power electronic converter is combined with the traditional phase-shifting transformer, so that the complexity of the power electronic converter can be reduced, the control is easy, and the advantages of small volume and light weight of the medium-high frequency transformer can be achieved. Therefore, a series 12-pulse rectifier using a low complexity power electronic transformer is produced.

Disclosure of Invention

The invention aims to reduce the volume and the weight of a phase-shifting transformer, improve the power density of a multi-pulse rectifier and reduce the complexity of a switching device of a power electronic converter, and further provides a series-type 12-pulse rectifier using a low-complexity power electronic transformer.

The purpose of the invention is realized by the following technical scheme:

the 12-pulse wave rectifier comprises an input inductor, a power electronic converter, a medium-high frequency phase-shifting transformer, a first three-phase full-bridge rectification circuit, and a second three-phase full-bridge rectification circuitThe circuit comprises a current circuit, a first direct current side capacitor, a second direct current side capacitor, a load and a PWM control circuit; the power electronic transformer is formed by the power electronic converter and the medium-high frequency phase-shifting transformer; the left end of the input inductor is connected with a three-phase voltage source respectively, and the right end of the input inductor is connected with the central point of each phase primary side double winding of the medium-high frequency phase-shifting transformer respectively; the synonym ends of two groups of windings of the medium-high frequency phase-shifting transformer are respectively connected with two groups of three-phase rectifier bridges of the power electronic converter; the on-off of two switching tubes of the power electronic converter is controlled by a control signal of the PWM control circuit; two secondary windings of the medium-high frequency phase-shifting transformer are respectively connected in a star shape and an angle shape, and the two secondary windings of the medium-high frequency phase-shifting transformer output two groups of three-phase voltages with the phase difference of 30 degrees; input end of first group of three-phase full-bridge rectification circuit and output end a of medium-high frequency phase-shifting transformer₁、b₁、c₁The input end of the second group of three-phase full-bridge rectifying circuits is connected with the output end a of the medium-high frequency phase-shifting transformer₂、b₂、c₂Connecting; the first group of three-phase full-bridge rectifying circuits and the second group of three-phase full-bridge rectifying circuits are connected in series, and the output voltage is doubled; the first direct current side capacitor is connected with the second direct current side capacitor in series; the first group of three-phase full-bridge rectifying circuits and the second group of three-phase full-bridge rectifying circuits are connected with the first direct-current side capacitor, the second direct-current side capacitor and the load in parallel.

The invention relates to a series 12-pulse rectifier using low-complexity power electronic transformer, and an input inductor L_sThe total inductance of the rectifier including the leakage inductance of the high-frequency transformer is respectively connected with a three-phase alternating current voltage source u_sa、u_sb、u_scAre connected in series.

The invention relates to a series 12-pulse rectifier using a low-complexity power electronic transformer, which is characterized in that: the power electronic transformer is composed of a power electronic transformer and a medium-high frequency phase-shifting transformer, the power electronic transformer is composed of a three-phase diode rectifier bridge, a switching tube, a diode and a clamping circuit, the phase difference of two groups of windings on the primary side of the medium-high frequency phase-shifting transformer is 180 degrees, and the first group of windings is connected with a three-phase diode rectifier bridge Rec3, the second group of windings is connected with a three-phase diode rectifier bridge Rec 4; the rectifier bridges Rec3 and Rec4 are respectively connected with the switch tube S₁And S₂Connected in parallel via a diode D₁、D₂And D₃、D₄Sharing a clamp circuit.

The invention relates to a series 12-pulse rectifier using a low-complexity power electronic transformer, wherein a control circuit consists of a voltage phase sampling circuit, a control signal generating circuit and a driving circuit, and the sampling circuit is used for sampling a voltage u_saSampling the phase, and sending the collected phase information to a control signal generating circuit; PWM control circuit uses high-frequency square wave signal with duty ratio of 0.5 to control switch tube S₁And S₂The input power frequency alternating current is converted into high-frequency alternating current by switching on and switching off; switch tube S₁And S₂Are tightly synchronized to ensure three-phase balance of the rectifier.

The invention relates to a series 12-pulse rectifier using a low-complexity power electronic transformer, wherein a medium-high frequency phase-shifting transformer adopts an isolation transformer structure to improve the reliability of the rectifier, the medium-high frequency phase-shifting transformer consists of 3 core columns, each core column is provided with 2 primary windings and 2 secondary windings, and the turn ratio of two groups of windings on the primary side of the high-frequency transformer meets N₁:N₂The phase difference is 180 degrees, 2 windings on the secondary side are respectively connected in a star shape and an angle shape, the turn ratio of the windings connected in the star shape to the windings connected in the angle shape is 1:1.73, and the amplitudes of two groups of three-phase voltages output by the secondary side winding of the power electronic transformer are equal; the star-connected winding has the same voltage phase as the primary winding, and the angle-connected winding has a phase difference of 30 degrees with the primary winding.

The invention relates to a series 12-pulse rectifier using a low-complexity power electronic transformer, wherein a first group of three-phase full-bridge rectifier circuits and a second group of three-phase full-bridge rectifier circuits are connected in series, and the output voltage is doubled; and the first direct current side capacitor and the second direct current side capacitor adopt large capacitor filtering.

The invention relates to a series 12-pulse rectifier using a low-complexity power electronic transformer, wherein a power electronic transformer and a medium-high frequency phase-shifting transformer jointly form the power electronic transformer, and input power frequency alternating current is converted into high-frequency alternating current by controlling the on-off of switching tubes S1 and S2 by using a high-frequency square wave signal with the duty ratio of 0.5, so that the volume and the quality of the phase-shifting transformer are reduced.

Compared with the prior art, the invention has the following beneficial effects:

1) compared with a power frequency autotransformer, the transformer has the advantages that the primary side and the secondary side are isolated, the reliability coefficient is high, and the transformation of voltage grades can be realized.

2) The power electronic converter has low complexity and is only suitable for two active switching devices.

3) The control mode is open-loop control, the control method is simple, and the control effect is stable.

4) The two rectifier bridges adopted by the invention are connected in series, the output voltage of the rectifier is doubled, and the invention is suitable for high-voltage occasions.

5) The output capacitor adopted by the invention is a large capacitor, and the output voltage of the rectifier is kept constant due to the voltage stabilizing effect of the large capacitor.

Drawings

FIG. 1 is a schematic diagram of the circuit structure of the present invention;

FIG. 2 is a diagram of an isolation transformer winding configuration employed in the present invention;

FIG. 3 is a switching function of the control signals of the switching tubes S1 and S2 of the power electronic converter of the present invention;

FIG. 4 is a diagram illustrating an input voltage waveform of an a-phase high-frequency transformer according to the present invention;

fig. 5 is a circuit diagram of an operating mode I of the power electronic converter of the present invention;

fig. 6 is a circuit diagram of an operating mode II of the power electronic converter of the present invention;

FIG. 7 is a diagram of a control circuit employed in the present invention;

in FIG. 1, u_sa、u_sb、u_scIs a three-phase AC power supply i_a、i_b、i_cFor three-phase input current, i_a3、i_b3、i_c3，i_a4、i_b4、i_c4For isolating the transformerCurrent of primary output winding of transformer i_a1、i_b1、i_c1For the output current of the angular-connection secondary winding of the medium-high frequency phase-shifting transformer, i.e. the input current of the first three-phase full-bridge rectification circuit group i_a2、i_b2、i_c2For the output current of the star-connected secondary winding of the medium-high frequency phase-shifting transformer, i.e. the input current of the second three-phase full-bridge rectification circuit group i_Rec1Is the output current of a first set of three-phase full-bridge rectifier circuits i_Rec2Is the output current of a second three-phase full-bridge rectifier circuit group i_oIs the load current. u. of_oIs the load voltage. In FIG. 2, a, b, c are primary windings of the middle-high frequency phase-shifting transformer, a₁、b₁、c₁、a₂、b₂、c₂Is a secondary winding of a medium-high frequency phase-shifting transformer. N is a radical of₁，N₂Is the number of turns of the primary winding, N₃The turns of winding are star-connected for secondary side, N₄The number of turns of the secondary side angle connection winding.

Detailed Description

The invention will be described in further detail below with reference to the accompanying drawings: the present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation is given, but the scope of the present invention is not limited to the following embodiments.