阅读说明：本技术 一种使用直流侧电压谐波注入法的串联型40脉波整流器 (Series 40-pulse rectifier using direct-current side voltage harmonic injection method ) 是由 孟凡刚 杜青筱 高蕾 李泉慧 黎太其 于 2020-07-23 设计创作，主要内容包括：本发明提供了一种使用直流侧无源电压谐波注入法的串联型40脉波整流器,属于电力电子技术领域。本发明中,隔离变压器用于产生两组相位差为18°的五相电压,为两组五相整流电路供电；在一个电源周期内,两组五相整流电路共有20种运行模态,每个二极管导通72°,谐波注入电路在每个电源周期内存在两种运行模态,两种模态的交替运行在注入变压器原边产生一个10倍电网电压频率的方波电压,此电压方波将增加整流器输入电压的阶梯数,从而达到抑制输入电压谐波的目的。本发明能够显著提高整流器的谐波抑制能力,兼顾整流器的交、直流侧电能质量；仅使用无源器件,无需添加额外的控制电路,结构简单、易于实现,谐波抑制代价较低。(The invention provides a series 40-pulse rectifier using a direct-current side passive voltage harmonic injection method, and belongs to the technical field of power electronics. In the invention, the isolation transformer is used for generating two groups of five-phase voltages with the phase difference of 18 degrees and supplying power to two groups of five-phase rectifying circuits; in a power supply period, the two groups of five-phase rectifying circuits have 20 operation modes, each diode is conducted for 72 degrees, the harmonic injection circuit has two operation modes in each power supply period, the two modes alternately operate on the primary side of the injection transformer to generate square wave voltage with 10 times of the power grid voltage frequency, and the voltage square wave increases the step number of the input voltage of the rectifier, so that the aim of inhibiting the input voltage harmonic is fulfilled. The invention can obviously improve the harmonic suppression capability of the rectifier and give consideration to the quality of the electric energy at the AC side and the DC side of the rectifier; only a passive device is used, an additional control circuit is not needed, the structure is simple, the implementation is easy, and the harmonic suppression cost is low.)

1. A series 40-pulse rectifier using a DC-side voltage harmonic injection method, the series 40-pulse rectifier using the DC-side voltage harmonic injection method comprising: the circuit comprises an input inductor (1), an isolation transformer (2), a first group of five-phase bridge rectifier circuit (3), a second group of five-phase bridge rectifier circuit (4), an output capacitor (5), a load (6), a harmonic injection transformer (7) and a single-phase full-wave rectifier circuit (8); the left side of the input inductor (1) is respectively connected with a three-phase alternating current voltage source u_sa、u_sbAnd u_scConnected in series, with the right side thereof being connected to an isolation transformer (2) respectively) The three primary windings are connected; two groups of five-phase outputs of the isolation transformer (2) are respectively connected with the input end of the first group of five-phase bridge rectifier circuit (3) and the input end of the second group of five-phase bridge rectifier circuit (4); the first group of five-phase bridge rectification circuits (3) and the second group of five-phase bridge rectification circuits (4) are connected in series and are connected with the output capacitor (5) and the load (6) in parallel; the primary side of the harmonic injection transformer (7) is connected with the midpoint M of the first group of five-phase bridge rectifier circuit (3) and the second group of five-phase bridge rectifier circuit (4) and the midpoint P of the output capacitor (5)₁The secondary side of the secondary side is connected with the negative pole of a load (6) through a center tap; the input end of the single-phase full-wave rectifying circuit (8) is connected with the secondary side of the harmonic injection transformer (7), and the output end of the single-phase full-wave rectifying circuit is connected to the anode of the load (6).

2. The series 40-pulse rectifier of claim 1, wherein: the input inductor (1) is composed of three inductors L with equal inductance values_sThe rectifier can be equivalent to a current source type rectifier.

3. The series 40-pulse rectifier of claim 1, wherein: the isolation transformer (2) consists of an A-phase core column, a B-phase core column and a C-phase core column; the phase A core column has 7 windings comprising 1 primary winding a and 6 secondary windings, which are marked as a in sequence₁To a₆(ii) a The phase B core column has 8 windings comprising 1 primary winding B and 7 secondary windings, which are sequentially marked as B₁To b₇(ii) a The C-phase core column has 7 windings comprising 1 primary winding C and 6 secondary windings, which are sequentially marked as C₁To c₆(ii) a The primary windings a, b and c are connected in an angular form, and the secondary windings are connected in a zigzag form; the turn ratio of each winding of the A-phase core column is N_a：N_a1：N_a2：N_a3：N_a4：N_a5：N_a6381.051: 42.339: 68.506: 26.166: 62.928: 49.772: 17.605, respectively; the turn ratio of each winding of the B-phase core column is N_b：N_b1：N_b2：N_b3：N_b4：N_b5：N_b6:N_b7381.051: 56.660: 8.851: 8.851: 56.660: 34.441: 34.441: 73.333, respectively; the turn ratio of each winding of the C-phase core column is N_c：N_c1：N_c2：N_c3：N_c4：N_c5：N_c6381.051: 42.339: 26.166: 68.506: 17.605: 49.772: 62.928, respectively; the output end of the isolation transformer (2) generates two groups of five-phase voltages with equal average value and 18-degree phase difference.

4. The series 40-pulse rectifier of claim 1, wherein: in the first group of five-phase bridge rectification circuits (3) and the second group of five-phase bridge rectification circuits (4), all used rectification devices are diodes; the two groups of five-phase bridge rectification circuits can be equivalently replaced by two current sources, and the waveforms of the two equivalent current sources are approximate 10 pulse waves with equal average values and 18-degree phase difference according to the winding structure and the turn ratio relation of the isolation transformer (2).

5. The series 40-pulse rectifier of claim 1, wherein: the output capacitor (5) is composed of two large capacitors C with equal capacitance values₁、C₂The load (6) can be equivalent to a constant voltage load.

6. The series 40-pulse rectifier of claim 1, wherein: the harmonic injection transformer (7) is a single-phase transformer and comprises a primary winding and two secondary windings, and the turn ratio of the primary winding to the secondary winding is N₁：N₂＝1:159.6。

7. The series 40-pulse rectifier of claim 1, wherein: in the single-phase full-wave rectification circuit (8), only passive devices are used.

Technical Field

The invention relates to a series 40-pulse rectifier using a direct-current side voltage harmonic injection method, and belongs to the technical field of power electronics.

Background

In a power electronic device, a rectifier is a common interface between an alternating current power grid and a direct current side electric device, wherein an uncontrolled multi-pulse rectifier has the advantages of simple structure, easiness in implementation, high reliability, strong overload capacity and the like, and is widely applied. However, the strong nonlinearity of the rectifying device still causes a certain harmonic pollution problem of the conventional multi-pulse rectifier, and the harmonic causes serious damage to the power grid and the electric equipment. How to improve the harmonic suppression capability of the rectifier has become one of the important research topics in the power electronic technology field today.

In general, the harmonic suppression capability of the rectifier is improved along with the increase of the pulse number, and two methods are mainly used for improving the pulse number of the rectifier, wherein one method is to increase the output phase number of the phase-shifting transformer, and the other method is to use a direct-current side passive or active harmonic suppression method; when only the former method is used, the phase-shifting transformer has larger volume and excessively complex winding structure; when only the method of harmonic suppression on the dc side is used, the harmonic suppression capability of the rectifier is limited, or the control circuit design is complicated, and the reliability is reduced. On the basis of properly increasing the output phase number of the phase-shifting transformer, the invention can construct a series 40-pulse rectifier by adding a direct-current side passive voltage harmonic suppression circuit. Compared with the conventional main circuit topology based on the three-phase rectifier bridge, the equivalent capacity, the design process and the complexity of the winding structure of the isolation transformer used in the invention are not obviously increased; in addition, rectifying devices in the harmonic suppression circuit are all passive devices, an additional control circuit is not needed, the harmonic suppression cost is low, and the system reliability is high.

Disclosure of Invention

The invention aims to improve the harmonic suppression capability of a high-power rectifier and the quality of electric energy at alternating current and direct current sides of the high-power rectifier, and further provides a series 40-pulse rectifier using a direct current side voltage harmonic injection method.

The technical scheme of the invention is as follows:

the invention provides a series-type 40-pulse rectifier using a direct-current side voltage harmonic injection method, which comprises the following components: the circuit comprises an input inductor, an isolation transformer, a first group of five-phase bridge rectifier circuits, a second group of five-phase bridge rectifier circuits, an output capacitor, a load, a harmonic injection transformer and a single-phase full-wave rectifier circuit; the input inductance is composed of three inductances L equal to each other_sThe left side of the three-phase alternating current power supply unit is respectively connected with a three-phase alternating current voltage source u_sa、u_sbAnd u_scThe three primary windings are connected in series, and the right sides of the three primary windings are respectively connected with the three primary windings of the isolation transformer; two groups of five-phase outputs of the isolation transformer are respectively connected with the input ends of the first group of five-phase bridge rectifier circuits and the second group of five-phase bridge rectifier circuits; the first group of five-phase bridge rectifier circuits are connected in series with the second group of five-phase bridge rectifier circuits and are connected with the output capacitor and the load in parallel; the output capacitance is composed of two large capacitances C with equal capacitance₁、C₂Are connected in series and are connected in parallel with a load; the primary side of the harmonic injection transformer is connected with the midpoint M of the first group of five-phase bridge rectifier circuits and the second group of five-phase bridge rectifier circuits and the midpoint P of the output capacitor₁The secondary side of the secondary side is provided with a center tap; the input end of the single-phase full-wave rectification circuit is connected with the secondary side of the harmonic injection transformer, and the output end of the single-phase full-wave rectification circuit is connected to two ends of the output capacitor.

The invention relates to a series 40-pulse rectifier using a direct-current side voltage harmonic injection method, wherein an input inductor comprises three inductors L with equal inductance values_sThe rectifier can be equivalent to a current source type rectifier.

The invention relates to a series connection type using a direct current side voltage harmonic injection methodThe isolation transformer consists of an A-phase core column, a B-phase core column and a C-phase core column; the phase A core column has 7 windings comprising 1 primary winding a and 6 secondary windings, which are marked as a in sequence₁To a₆(ii) a The phase B core column has 8 windings comprising 1 primary winding B and 7 secondary windings, which are sequentially marked as B₁To b₇(ii) a The C-phase core column has 7 windings comprising 1 primary winding N_cAnd 6 secondary windings, denoted in sequence by c₁To c₆(ii) a The primary windings a, b and c are connected in an angular form, and the secondary windings are connected in a zigzag form; the turn ratio of each winding of the A-phase core column is N_a：N_a1：N_a2：N_a3：N_a4：N_a5：N_a6381.051: 42.339: 68.506: 26.166: 62.928: 49.772: 17.605, respectively; the turn ratio of each winding of the B-phase core column is N_b：N_b1：N_b2：N_b3：N_b4：N_b5：N_b6:N_b7381.051: 56.660: 8.851: 8.851: 56.660: 34.441: 34.441: 73.333, respectively; the turn ratio of each winding of the C-phase core column is N_c：N_c1：N_c2：N_c3：N_c4：N_c5：N_c6381.051: 42.339: 26.166: 68.506: 17.605: 49.772: 62.928, respectively; two sets of five-phase voltages with equal average values and 18 ° phase difference are thereby generated.

The invention relates to a series 40-pulse rectifier using a direct-current side voltage harmonic injection method, wherein in a first group of five-phase bridge rectifier circuits and a second group of five-phase bridge rectifier circuits, all used rectifier devices are diodes; the two groups of five-phase bridge rectification circuits can be equivalently replaced by two current sources, and the waveforms of the two equivalent current sources are approximate 10 pulse waves with equal average values and 18-degree phase difference according to the winding structure and the turn ratio relation of the isolation transformer.

The invention relates to a series 40-pulse rectifier using a direct-current side voltage harmonic injection method, wherein an output capacitor is composed of two large capacitors C with equal capacitance values₁、C₂The load can be equivalent to a constant voltage load.

The invention relates to a series 40-pulse rectifier using a direct-current side voltage harmonic injection method, wherein a harmonic injection transformer is a single-phase transformer and comprises a primary winding and two secondary windings, and the turn ratio of the primary winding to the secondary winding is N₁：N₂＝1:159.6。

The invention provides a series type 40-pulse rectifier using a direct current side voltage harmonic injection method, wherein only passive devices are used in a single-phase full-wave rectification circuit.

The invention relates to a series 40-pulse rectifier using a direct-current side voltage harmonic injection method, which is characterized in that a basic topology of the series rectifier is formed by two groups of five-phase bridge rectifier circuits, and a direct-current side passive voltage harmonic injection circuit is used in a matching manner, so that compared with a series 12-pulse rectifier formed by two groups of three-phase bridge rectifier circuits, the harmonic suppression capability of the series 12-pulse rectifier is obviously improved; the phase-shifting transformer is an isolation transformer, can provide electrical isolation for the alternating current side and the direct current side of the rectifier, is beneficial to protecting electric equipment and expands the application range of the rectifier; the equivalent capacity of the harmonic injection transformer only accounts for 0.33% of the load power, the volume is small, and the harmonic suppression cost is low; all the used rectifying devices are passive devices, and no additional control circuit is needed, so that the circuit structure is simplified, and the reliability of the system is improved; the invention is suitable for high-voltage and high-power rectification occasions with higher requirements on the quality of electric energy.

Drawings

The above and other objects, features and advantages of the present invention will become more apparent by describing the present invention with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of a series 40-pulse rectifier using a DC-side voltage harmonic injection method according to the present invention;

FIG. 2 is a diagram of the winding structure of the isolation transformer of the present invention;

FIG. 3 is a winding structure diagram of the harmonic injection transformer of the present invention;

FIG. 4 is a circuit diagram of the working mode I of the passive harmonic injection circuit of the present invention;

fig. 5 is a circuit diagram of the operating mode ii of the passive harmonic injection circuit of the present invention.

FIG. 6 shows the voltage u in the sixth embodiment_AnIs related to the turn ratio n of the harmonic injection transformer.

In FIGS. 1 to 5, u_sa、u_sbAnd u_scIs a three-phase alternating current voltage source; i.e. i_a、i_bAnd i_cThree-phase input current; i.e. i₁、i₂And i₃Is the primary winding current of the isolation transformer; i.e. i_a1、i_b1、i_c1、i_d1And i_e1The input current of the first group of five-phase bridge rectifier circuits; i.e. i_a2、i_b2、i_c2、i_d2And i_e2The input current of the second group of five-phase bridge rectifier circuits; i.e. i_Rec1The output current of the first group of five-phase bridge rectifier circuits; i.e. i_Rec2The output current of the second group of five-phase bridge rectifier circuits; i.e. i_xInjecting a primary winding current of the transformer for the harmonic; i.e. i_D1And i_D2The secondary winding current of the transformer is injected into the harmonic wave, namely the current flows through a diode D in the single-phase full-wave rectification circuit₁And D₂The current of (a); i.e. i_oIs the load current; u. of_oIs the load voltage; m is the middle point of two groups of five-phase bridge rectifier circuits; p₁Is the reference point of the first group of five-phase bridge rectifier circuit, namely the output capacitor C₁And C₂A midpoint of (a); p₂Is a reference point of the second group of five-phase bridge rectifier circuits; n is a radical of_a、N_bAnd N_cThe number of turns of a primary winding of the isolation transformer is set; n is a radical of_a1、N_a2、N_a3、N_a4、N_a5And N_a6The number of turns of a secondary winding of the phase a core column of the isolation transformer is set; n is a radical of_b1、N_b2、N_b3、N_b4、N_b5、N_b6And N_b7The number of turns of a secondary winding of a phase b core column of the isolation transformer is set; n is a radical of_c1、N_c2、N_c、N_c4、N_c5And N_c6The number of turns of a secondary winding of a c-phase core column of the isolation transformer is set; n is a radical of₁Injecting the number of turns of a primary winding of the transformer for harmonic waves; n is a radical of₂And injecting the number of turns of the secondary winding of the transformer for harmonic waves.

Reference numerals in the drawings: 1 is an input inductor; 2 is an isolation transformer; 3 is a first group of five-phase bridge rectifier circuit; 4 is a second group of five-phase bridge rectifier circuits; 5 is an output capacitor; 6 is a load; 7 is a harmonic injection transformer; and 8 is a single-phase full-wave rectifying circuit.

Detailed Description

The invention is 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.