阅读说明：本技术 使用直流侧混合谐波抑制方法的串联型60脉波整流器 (Series 60-pulse rectifier using DC side mixed harmonic suppression method ) 是由 孟凡刚 李泉慧 高蕾 黎太其 杜青筱 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混合谐波抑制方法的串联型60脉波整流器,属于电力电子技术领域。本发明的隔离变压器采用Δ/Δ/Y型连接,可以有效抑制由于三相不平衡因素所产生的三次谐波；谐波注入电路由无源谐波注入电路和有源谐波注入电路组成,无源谐波注入电路包括单相注入变压器以及单相全波整流电路,有源谐波注入电路包括两个开关管和两组控制电路；无源谐波注入电路和有源谐波注入电路共同工作,产生6倍电源频率的阶梯波调制信号,对整流桥输出电压进行调制,达到抑制整流器输入电压、电流谐波的目的。本发明所采用的谐波注入电路体积小,注入变压器容量小,谐波抑制代价低,谐波抑制效果显著。本发明适用于大功率场合。(The invention provides a series 60-pulse rectifier using a direct current side hybrid harmonic suppression method, and belongs to the technical field of power electronics. The isolation transformer adopts delta/Y type connection, so that third harmonic generated by three-phase unbalance factors can be effectively inhibited; the harmonic injection circuit consists of a passive harmonic injection circuit and an active harmonic injection circuit, the passive harmonic injection circuit comprises a single-phase injection transformer and a single-phase full-wave rectification circuit, and the active harmonic injection circuit comprises two switching tubes and two groups of control circuits; the passive harmonic injection circuit and the active harmonic injection circuit work together to generate a step wave modulation signal with 6 times of power supply frequency, and the step wave modulation signal modulates the output voltage of the rectifier bridge to achieve the purpose of suppressing the input voltage and current harmonic of the rectifier. The harmonic injection circuit adopted by the invention has small volume, the injection transformer has small capacity, the harmonic suppression cost is low, and the harmonic suppression effect is obvious. The invention is suitable for high-power occasions.)

1. A series 60-pulse rectifier using a DC-side hybrid harmonic suppression method, comprising: the circuit comprises an input inductor (1), an isolation transformer (2), a first group of three-phase full-bridge rectification circuits (3), a second group of three-phase full-bridge rectification circuits (4), a harmonic injection circuit (5), a clamping diode (6), a first group of control circuits (7), a second group of control circuits (8), a first direct-current side capacitor (9), a second direct-current side capacitor (10) and a load (11);

the left end of the input inductor (1) is connected with a three-phase voltage source respectively, and the right end of the input inductor (1) is connected with a primary winding of the isolation transformer (2); two groups of secondary windings of the isolation transformer (2) are respectively connected with the input ends of the first group of three-phase full-bridge rectification circuits (3) and the second group of three-phase full-bridge rectification circuits (4); the three-phase full-bridge rectifier circuit (3) and the three-phase full-bridge rectifier circuit (4) are connected in series, and the three-phase full-bridge rectifier circuit (3) and the three-phase full-bridge rectifier circuit (4) are connected in parallel with a first direct-current side capacitor (9), a second direct-current side capacitor (10) and a load (11); the rectifier output voltage becomes twice; the upper end of a first direct current side capacitor (9) and the output end of a first group of three-phase full-bridge rectification circuits (3)The positive pole of the load (11) is connected with the positive pole of the first direct current side capacitor (9), the lower end of the first direct current side capacitor (9) is connected with the upper end of the second direct current side capacitor (10), and the lower end of the second direct current side capacitor (10) is connected with the negative pole of the output end of the second group of three-phase full-bridge rectification circuits (4) and the negative pole of the load (11); the harmonic injection circuit (5) is composed of an injection transformer, a single-phase full-wave rectification circuit and two switching tubes, wherein a primary winding of the injection transformer is respectively connected with a connection point of two groups of three-phase full-bridge rectification circuits and a midpoint of two direct-current side capacitors, and the positive electrode of the output end of the single-phase full-wave rectification circuit is connected with the switching tube Q₁And Q₂The collector of the single-phase full-wave rectifying circuit is connected with the anode of a clamping diode (6), and the cathode of the output end of the single-phase full-wave rectifying circuit is connected with a switching tube Q₁The emitter of the first direct current side capacitor (10), the negative electrode of the second direct current side capacitor (10) and the negative electrode of the load (11) are connected; switch tube Q₂The emitting electrodes of the switching tubes Q1 and Q2 are respectively connected with the output ends of the first group of control circuits (7) and the second group of control circuits (8); the cathode of the clamping diode (6) is connected with the anode of the load (11); the sampling ends of the first group of control circuits (7) and the second group of control circuits (8) are connected with the homonymous end of the injection transformer.

2. The series type 60-pulse rectifier using the dc-side hybrid harmonic suppression method according to claim 1, wherein: the input inductor (1) is composed of three large inductors with the same size, and an input power supply is equivalent to a three-phase balanced current source due to the filtering effect of the large inductors.

3. The series type 60-pulse rectifier using the dc-side hybrid harmonic suppression method according to claim 1, wherein: the isolation transformer (2) is a phase-shifting transformer, and the primary side and the secondary side of the transformer are electrically isolated, so that the safety is high; the isolation transformer (2) is composed of three core columns, each core column is provided with 3 windings, each winding comprises 1 primary side winding and 2 secondary side windings, the turn ratio of each winding is N1: N2: N3: 1.73:1, the windings are independent of each other, the primary side windings form triangular connection, and the secondary side windings form star connection and angular connection to generate two groups of three-phase voltages with equal size and 30-degree phase difference.

4. The series 48-pulse rectifier using the dc-side hybrid harmonic suppression method according to claim 1, wherein: the first group of three-phase full-bridge rectifying circuits (3) and the second group of three-phase full-bridge rectifying circuits (4) adopt uncontrolled rectifying devices.

5. The series 48-pulse rectifier using the dc-side hybrid harmonic suppression method according to claim 1, wherein: the first direct current side capacitor (9) and the second direct current side capacitor (10) are two large capacitors with the same size.

6. The series type 60-pulse rectifier using the dc-side hybrid harmonic suppression method according to claim 1, wherein: the harmonic injection circuit (5) consists of an injection transformer, a single-phase full-wave rectification circuit and two switching tubes, wherein the injection transformer consists of a core column, each core column is provided with a primary winding and two secondary windings, the single-phase full-wave rectification circuit consists of two diodes, and the two switching tubes are not arranged in the main circuit.

7. The series type 60-pulse rectifier using the dc-side hybrid harmonic suppression method according to claim 1, wherein: the harmonic injection circuit (5) is composed of a passive harmonic suppression circuit and an active harmonic suppression circuit.

8. The series type 60-pulse rectifier using the dc-side hybrid harmonic suppression method according to claim 1, wherein: the control circuit controls the two switching tubes to work alternately by controlling the on and off of the switching tubes, and injects voltage harmonic waves to the direct current side of the rectifier to modulate the output voltage of the rectifier bridge, so that the alternating current harmonic waves are effectively inhibited.

9. The series type 60-pulse rectifier using the dc-side hybrid harmonic suppression method according to claim 1, wherein: harmonic injection circuit (5)Turn ratio of the middle injection transformer is N₇/N₈＝0.0285。

Technical Field

The invention relates to a series 60-pulse rectifier using a direct current side hybrid harmonic suppression method, and belongs to the technical field of power electronics.

Background

The multi-pulse rectifier is simple in structure and strong in robustness, and is widely applied to the field of high-power electric energy conversion and electric energy transmission. However, diode rectification is often used in multi-pulse rectifiers, which generate a large number of harmonics due to the strong non-linearity of the diodes, and also generate a large number of non-characteristic subharmonics due to the three-phase imbalance of the power supply. To solve the above problems, an effective method for suppressing the input current and voltage harmonics of the multi-pulse rectifier is urgently needed.

The key for improving the input and output electric energy quality of the multi-pulse rectifier is to improve the pulse number of the output voltage and current of the rectifier, and the more the pulse number of the output voltage and current of the rectifier is, the higher the input and output electric energy quality of the rectifier is. There are several methods for increasing the output voltage and current pulse number of the multi-pulse rectifier, among which, the most common methods are two, one is to increase the number of the rectifier bridges connected in series or in parallel by increasing the output phase number of the phase-shifting transformer, but when the output phase number of the phase-shifting transformer exceeds 3, the structure of the transformer is complex, the design is difficult and the asymmetry problem is serious; the other method is to use a direct current side harmonic suppression method, which comprises a direct current side passive harmonic suppression method, an active harmonic suppression method and a mixed harmonic suppression method, and to inject voltage or current harmonics to the direct current side of the rectifier to counteract specific times of harmonics generated by the rectifier, wherein the direct current side passive harmonic suppression method does not need a switching tube and a control circuit, the circuit has high reliability but limited harmonic suppression capability, the direct current side active harmonic suppression method has obvious harmonic suppression effect but low reliability, and the harmonic injection circuit has large loss, and the direct current side mixed harmonic suppression method combines the two methods, takes the advantages of the two methods into consideration, has high reliability and low loss, and is the most common method in the current multi-pulse rectification technology. By combining the method for improving the electric energy quality of the multi-pulse rectifier, the invention provides a series 60-pulse rectifier using a direct current side mixed harmonic suppression method, wherein the direct current side passive harmonic suppression method and the active harmonic suppression method are combined, the direct current side passive harmonic suppression method is used for suppressing low-order harmonics generated by the rectifier, and the active harmonic suppression method is used for suppressing higher harmonics generated by the rectifier; compared with a rectifier without a harmonic injection circuit, the input voltage THD value is reduced to below 1% from 12%, and the electric energy quality of the rectifier is greatly improved.

Disclosure of Invention

In order to improve the harmonic suppression capability of a multi-pulse rectifier, the invention provides a series 60-pulse rectifier using a direct current side mixed harmonic suppression method.

In order to achieve the purpose, the invention adopts the technical scheme that:

a series 60-pulse rectifier using a dc-side hybrid harmonic suppression method, comprising: the device comprises an input inductor, an isolation transformer, a first group of three-phase full-bridge rectifying circuits, a second group of three-phase full-bridge rectifying circuits, a harmonic injection circuit, a clamping diode, a first group of control circuits, a second group of control circuits, a first direct-current side capacitor, a second direct-current side capacitor and a load;

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 a primary winding of the isolation transformer; two groups of secondary windings of the isolation transformer are respectively connected with the input ends of the first group of three-phase full-bridge rectification circuits and the second group of three-phase full-bridge rectification circuits; 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 first group of three-phase full-bridge rectifying circuits and the second group of three-phase full-bridge rectifying circuits are connected in parallel with a first direct-current side capacitor, a second direct-current side capacitor and a load; the rectifier output voltage becomes twice; the upper end of a first direct current side capacitor is connected with the positive electrode of the output end of the first group of three-phase full-bridge rectification circuits and the positive electrode of the load, the lower end of the first direct current side capacitor is connected with the upper end of a second direct current side capacitor, and the lower end of the second direct current side capacitor is connected with the negative electrode of the output end of the second group of three-phase full-bridge rectification circuits and the negative electrode of the load; the harmonic injection circuit consists of an injection transformer, a single-phase full-wave rectification circuit and two switching tubes, wherein a primary winding of the injection transformer in the single-phase full-wave rectification circuit is respectively connected with a connection point of two groups of three-phase full-bridge rectification circuits and a midpoint of two direct-current side capacitors, the positive electrode of the output end of the single-phase full-wave rectification circuit is connected with the collectors of the switching tubes Q1 and Q2 and the anode of a clamping diode, and the negative electrode of the output end of the single-phase full-wave rectification circuit is connected with the emitter of the switching tube Q1, the negative electrode of a second direct-current; the emitter of the switching tube Q2 is connected with the connection point of the two direct current side capacitors, and the grids of the switching tubes Q1 and Q2 are respectively connected with the output ends of the first group of control circuits and the second group of control circuits; the cathode of the clamping diode is connected with the anode of the load; and the sampling ends of the first group of control circuits and the second group of control circuits are connected with the homonymous end of the injection transformer.

The invention uses the series 60 pulse wave rectifier of the mixed harmonic suppression method of direct current side, the input inductance is formed by three big inductances with the same size, because of the filtering function of the big inductance, the input power is equivalent to a three-phase balanced current source.

The series 60-pulse rectifier adopting the direct current side mixed harmonic suppression method is adopted, the isolation transformer is a phase-shifting transformer, the primary side and the secondary side of the transformer are electrically isolated, and the safety is high; the isolation transformer consists of three core columns, each core column is provided with 3 windings, each winding comprises 1 primary side winding and 2 secondary side windings, the turn ratio of each winding is N1: N2: N3 is 1.73:1.73:1, the windings are mutually independent, the primary side windings form triangular connection, the output power is improved, the secondary side windings form star connection and angular connection, and two groups of three-phase voltages with equal size and 30-degree phase difference are generated.

The invention uses a series 48-pulse rectifier of a direct current side mixed harmonic suppression method, and a first group of three-phase full-bridge rectification circuits and a second group of three-phase full-bridge rectification circuits adopt uncontrolled rectification devices.

The invention uses a series 48-pulse rectifier of a direct current side mixed harmonic suppression method, and a first direct current side capacitor and a second direct current side capacitor are two large capacitors with the same size.

The invention uses the series 60 pulse wave rectifier of the mixed harmonic suppression method of direct current side, the harmonic injection circuit is made up of an injection transformer, a single-phase full-wave rectifier circuit and two switching tubes, the injection transformer is made up of a core column, there are a primary winding and two secondary windings on each core column, the injection transformer is small, the capacity is low, the harmonic suppression cost is small, the single-phase full-wave rectifier circuit is made up of two diodes only, the loss is small, two switching tubes are not in the main circuit, the current flowing through the switching tube is small, the switching loss is low.

The invention relates to a series 60-pulse rectifier using a direct current side mixed harmonic suppression method, wherein a harmonic injection circuit consists of a passive harmonic suppression circuit and an active harmonic suppression circuit.

According to the series 60-pulse rectifier adopting the direct current side mixed harmonic suppression method, the control circuit controls the two switching tubes to work alternately by controlling the on-off of the switching tubes, voltage harmonics are injected into the direct current side of the rectifier, and the output voltage of a rectifier bridge is modulated, so that alternating current harmonic measurement is effectively suppressed

The invention uses a series 60-pulse rectifier of a direct current side mixed harmonic suppression method, and the turn ratio of an injection transformer in a harmonic injection circuit is N7/N8-0.0285.

Compared with the prior art, the series 60-pulse rectifier using the direct current side hybrid harmonic suppression method has the following beneficial effects:

1) the secondary winding of the isolation transformer adopted by the invention is in star-delta connection, so that 3k harmonic waves generated by the rectifier are effectively inhibited.

2) The harmonic injection circuit adopted by the invention consists of the passive harmonic injection circuit and the active harmonic injection circuit, the harmonic injection circuit has better adaptability, and even if the switch tube fails, the passive harmonic injection circuit can still work and still has a certain inhibiting effect on the harmonic.

3) The rectifier bridge adopted by the invention is a diode rectifier bridge, does not need complex control, has high reliability and is suitable for high-power occasions.

4) The input inductor adopted by the invention is connected with the input power supply and the phase-shifting transformer, the input power supply is equivalent to a current source, and the quality of the input current and the electric energy of the rectifier is improved due to the filtering effect of the inductor.

5) 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.

6) 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 diagram of an injection transformer winding configuration employed in the present invention;

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

FIG. 5 is a circuit diagram of the working mode II of the harmonic injection circuit employed in the present invention;

FIG. 6 is a circuit diagram of the working mode III of the harmonic injection circuit employed in the present invention;

FIG. 7 is a circuit diagram of the working mode IV of the harmonic injection circuit employed in the present invention;

FIG. 8 is a circuit diagram of the mode V of operation of the harmonic injection circuit employed in the present invention;

FIG. 9 is a circuit diagram of the operating mode VI of the harmonic injection circuit employed in the present invention;

fig. 10 is an operation waveform of the control circuits 7 and 8 employed in the present invention;

FIG. 11 is a waveform illustrating operation of a rectifier employed in the present invention;

FIG. 12 is a graph showing the variation of the input voltage THD of the rectifier in accordance with the present invention and the turn ratio of the injection transformer;

fig. 13 is a diagram of a rectifier input voltage waveform employed in the present invention.

In FIGS. 1 to 13, u_sa、u_sb、u_scIs a three-phase voltage source i_a、i_b、i_cFor three-phase input current, i_a1、i_b1、i_c1For a first set of three-phase full-bridge rectifier circuits input currents i_a2、i_b2、i_c2For a second three-phase full-bridge rectifier circuit input current i_xFor injecting a current i into the primary winding of the transformer_Rec1For a first set of three-phase full-bridge rectifier circuits output currents, i_Rec2For a second set of three-phase full-bridge rectifier circuits output current, N₁For isolating the number of turns of the primary winding of the transformer, N₂、N₃For isolating the number of turns of the secondary winding of the transformer, N₄For injecting the number of turns of the primary winding of the transformer, N₅The number of turns of the secondary winding of the transformer is injected.

Reference numbers in the figures: 1 is an input inductor; 2 is an isolation transformer; 3 is a first group of three-phase full-bridge rectifying circuits; 4 is a second group of three-phase full-bridge rectifying circuits; 5 is a harmonic injection circuit; 6 is a clamping diode; 7 is a first set of control circuits; 8 is a second set of control circuits; 9 is a first direct current side capacitor; 10 is a second direct current side capacitor; and 11 is a load.

Detailed Description