阅读说明：本技术 使用直流侧无源谐波抑制方法的串联型多脉波整流器 (Series-connection type multi-pulse rectifier using direct-current side passive harmonic suppression method ) 是由 王清媛 丁永强 于 2020-08-05 设计创作，主要内容包括：本发明实施例公开了一种使用直流侧无源谐波抑制方法的串联型多脉波整流器,包括输入电感、移相变压器、第一三相全桥整流电路、第二三相全桥整流电路、第一直流侧电容、第二直流侧电容、负载、谐波注入电路,谐波注入电路由一个单相变压器和一个单相全桥整流电路组成,单相变压器由一个原边绕组和一个副边绕组组成；单相全桥整流电路的输出端正极与第二三相全桥整流电路的负极相连,输出端负极与负载的负极相连。本发明使用直流侧无源谐波抑制方法来抑制整流器输入电压、电流中的谐波,与不使用谐波注入电路的整流器相比,输入电压THD值由12%降低到4%,整流器输入电压符合IEEE标准,极大改善了整流器的输入电能质量。(The embodiment of the invention discloses a series-connection type multi-pulse rectifier using a direct current side passive harmonic suppression method, which comprises an input inductor, a phase-shifting transformer, a first three-phase full-bridge rectification circuit, a second three-phase full-bridge rectification circuit, a first direct current side capacitor, a second direct current side capacitor, a load and a harmonic injection circuit, wherein the harmonic injection circuit consists of a single-phase transformer and a single-phase full-bridge rectification circuit, and the single-phase transformer consists of a primary side winding and a secondary side winding; the positive pole of the output end of the single-phase full-bridge rectification circuit is connected with the negative pole of the second three-phase full-bridge rectification circuit, and the negative pole of the output end is connected with the negative pole of the load. The invention uses the direct current side passive harmonic suppression method to suppress the harmonic in the input voltage and current of the rectifier, compared with the rectifier without the harmonic injection circuit, the input voltage THD value is reduced from 12% to 4%, the input voltage of the rectifier conforms to the IEEE standard, and the input electric energy quality of the rectifier is greatly improved.)

1. A series-connection multi-pulse rectifier using a direct current side passive harmonic suppression method comprises an input inductor, a phase-shifting transformer, a first three-phase full-bridge rectification circuit, a second three-phase full-bridge rectification circuit, a first direct current side capacitor, a second direct current side capacitor and a load, wherein the input inductor consists of three inductors with the same size; the primary winding of the phase-shifting transformer is connected in a triangular mode, the secondary winding of the phase-shifting transformer is connected in a star angle mode, three taps of the primary winding of the phase-shifting transformer are connected with a three-phase alternating-current power supply through three inductors respectively, and the secondary winding of the phase-shifting transformer is connected with the input ends of a first three-phase full-bridge rectification circuit and a second three-phase full-bridge rectification circuit respectively; the multi-pulse-wave rectifier is characterized by further comprising a harmonic injection circuit, wherein the harmonic injection circuit consists of a single-phase transformer and a single-phase full-bridge rectification circuit, and the single-phase transformer consists of a primary winding and a secondary winding; one side of a primary winding of the single-phase transformer is connected with the middle points of the two groups of three-phase full-bridge rectification circuits, the other side of the primary winding of the single-phase transformer is connected with the middle points of the first direct-current side capacitor and the second direct-current side capacitor, and a secondary winding of the single-phase transformer is respectively connected with the input end of the single-phase full-bridge rectification circuit; the positive electrode of the output end of the single-phase full-bridge rectifying circuit is connected with the negative electrode of the second three-phase full-bridge rectifying circuit, and the negative electrode of the output end is connected with the negative electrode of the load; the positive electrode of the first direct current side capacitor is connected with the positive electrode of the first three-phase full-bridge rectifying circuit and the positive electrode of the load, and the negative electrode of the first direct current side capacitor is connected with the positive electrode of the second direct current side capacitor and the middle point of the two groups of three-phase full-bridge rectifying circuits; and the negative electrode of the second direct-current side capacitor is connected with the negative electrode of the second three-phase full-bridge rectification circuit.

2. The series multi-pulse rectifier using the dc-side passive harmonic suppression method according to claim 1, wherein the phase-shifting transformer is an isolation transformer, and the primary and secondary sides of the isolation transformer are electrically isolated; the isolation transformer 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 windings are mutually independent, the primary side windings form triangular connection, and the secondary side windings form star connection and angle connection, so that two groups of three-phase voltages with equal size and 30-degree phase difference are generated.

3. The series-type multipulse rectifier using dc-side passive harmonic suppression method according to claim 1, wherein the first three-phase full-bridge rectifier circuit and the second three-phase full-bridge rectifier circuit each employ an uncontrolled rectifier device.

4. The series multi-pulse rectifier using the dc-side passive harmonic suppression method as claimed in claim 1, wherein the first dc-side capacitor and the second dc-side capacitor are two capacitors of equal size.

5. The series multi-pulse rectifier using dc-side passive harmonic suppression as claimed in claim 1 wherein the single-phase full-bridge rectifier circuit is comprised of four diodes.

6. The series multi-pulse rectifier using the dc-side passive harmonic suppression method according to claim 1, wherein a turn ratio of the single-phase transformer is 1.2: 1.

Technical Field

The invention relates to the technical field of electric power, in particular to a series multi-pulse rectifier using a direct current side passive harmonic suppression method.

Background

The multi-pulse rectifier is simple in structure and strong in robustness, and is often used as an interface of a high-power electronic device and an alternating current power grid. However, the rectifier adopts diode rectification, high reliability is obtained, and simultaneously, a large amount of harmonic pollution is also avoided, and in addition, a large amount of harmonic waves are generated due to the asymmetric transformer structure. 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 step number of the input voltage or current of the multi-pulse rectifier is equal to the pulse number of the output voltage or current, the more the step number of the input voltage or current is, the closer the waveform is to sine, and the less the harmonic content of the voltage or current is; the more the output voltage and current pulse number are, the closer the waveform is to the direct current, and the higher the electric energy quality is.

Therefore, the key to improve the quality of the input and output electric energy of the multi-pulse rectifier is to increase the output voltage and current pulse number of the multi-pulse rectifier. The method for improving the input and output voltage or current pulse number of the multi-pulse rectifier comprises two methods, one method is to increase the number of rectifier bridges connected in series or in parallel by increasing the number of output ends of a phase-shifting transformer and the number of taps of a balance reactor, but when the number of the rectifier bridges is too large, the phase-shifting transformer and the balance reactor are difficult to design and the imbalance phenomenon is serious; the other method is to eliminate some specific times of harmonic waves in the input voltage and current of the rectifier by using a direct current side harmonic wave suppression method, and compared with the method for increasing the number of rectifier bridges, the method has the advantages that the number of the rectifier bridges is small, and the loss is low; compared with the direct current side active harmonic suppression method, the direct current side passive harmonic suppression method injects voltage or current signals with specific frequency and shape into the direct current side of the rectifier by means of the characteristics of the circuit, so that harmonic suppression cost is low and reliability is high.

The invention patent with the application number of 2018104096783 entitled "series 36-pulse rectifier using dc-side mixed voltage harmonic injection method" uses dc-side mixed voltage harmonic injection method, but it has poor harmonic suppression effect and low circuit reliability, and is not satisfactory.

Disclosure of Invention

The technical problem to be solved by the embodiments of the present invention is to provide a series multi-pulse rectifier using a dc side passive harmonic suppression method, so as to improve the harmonic suppression effect and improve the robustness.

In order to solve the above technical problem, an embodiment of the present invention provides a series multi-pulse rectifier using a dc-side passive harmonic suppression method, including an input inductor, a phase-shifting transformer, a first three-phase full-bridge rectification circuit, a second three-phase full-bridge rectification circuit, a first dc-side capacitor, a second dc-side capacitor, and a load, where the input inductor is composed of three equal inductors; the primary winding of the phase-shifting transformer is connected in a triangular mode, the secondary winding of the phase-shifting transformer is connected in a star angle mode, three taps of the primary winding of the phase-shifting transformer are connected with a three-phase alternating-current power supply through three inductors respectively, and the secondary winding of the phase-shifting transformer is connected with the input ends of a first three-phase full-bridge rectification circuit and a second three-phase full-bridge rectification circuit respectively; the multi-pulse rectifier further comprises a harmonic injection circuit, wherein the harmonic injection circuit consists of a single-phase transformer and a single-phase full-bridge rectification circuit, and the single-phase transformer consists of a primary winding and a secondary winding; one side of a primary winding of the single-phase transformer is connected with the middle points of the two groups of three-phase full-bridge rectification circuits, the other side of the primary winding of the single-phase transformer is connected with the middle points of the first direct-current side capacitor and the second direct-current side capacitor, and a secondary winding of the single-phase transformer is respectively connected with the input end of the single-phase full-bridge rectification circuit; the positive electrode of the output end of the single-phase full-bridge rectifying circuit is connected with the negative electrode of the second three-phase full-bridge rectifying circuit, and the negative electrode of the output end is connected with the negative electrode of the load; the positive electrode of the first direct current side capacitor is connected with the positive electrode of the first three-phase full-bridge rectifying circuit and the positive electrode of the load, and the negative electrode of the first direct current side capacitor is connected with the positive electrode of the second direct current side capacitor and the middle point of the two groups of three-phase full-bridge rectifying circuits; and the negative electrode of the second direct-current side capacitor is connected with the negative electrode of the second three-phase full-bridge rectification circuit.

Furthermore, the phase-shifting transformer is an isolation transformer, and the primary side and the secondary side of the isolation transformer are electrically isolated; the isolation transformer 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 windings are mutually independent, the primary side windings form triangular connection, and the secondary side windings form star connection and angle connection, so that two groups of three-phase voltages with equal size and 30-degree phase difference are generated.

Furthermore, the first three-phase full-bridge rectification circuit and the second three-phase full-bridge rectification circuit both adopt uncontrolled rectification devices.

Furthermore, the first direct current side capacitor and the second direct current side capacitor are two capacitors with equal size.

Further, the single-phase full-bridge rectification circuit is composed of four diodes.

Further, the turn ratio of the single-phase transformer is 1.2: 1.

The invention has the beneficial effects that: the invention adopts the secondary winding of the isolation transformer as star-delta connection, and effectively inhibits the 3k harmonic generated by the rectifier; the harmonic injection circuit adopts the passive harmonic suppression circuit, compared with the direct current side active harmonic suppression method, the direct current side passive harmonic suppression method injects voltage or current signals with specific frequency and shape to the direct current side of the rectifier by means of the characteristics of the circuit, and the harmonic suppression cost is low and the reliability is high; 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; the input inductor adopted by the invention consists of three millihenry level inductors with the same size, and because the inductor has high impedance to higher-order current harmonics, harmonic components in the input current of the rectifier can be ignored, and the input current is equivalent to a sine wave; the two rectifier bridges adopted by the invention are connected in series, the output voltage of the rectifier is doubled, and the rectifier is suitable for high-voltage occasions; 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 circuit diagram of a series multi-pulse rectifier using a dc-side passive harmonic suppression method according to an embodiment of the present invention.

Fig. 2 is a structural diagram of an isolation transformer winding according to an embodiment of the present invention.

Fig. 3 is a structure diagram of a winding of a single-phase transformer according to an embodiment of the present invention.

Fig. 4 is a circuit diagram of the operation mode I of the harmonic injection circuit according to the embodiment of the present invention.

Fig. 5 is a circuit diagram of the harmonic injection circuit operating mode II according to an embodiment of the present invention.

Fig. 6 is a circuit diagram of a mode III of operation of the harmonic injection circuit according to an embodiment of the present invention.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application can be combined with each other without conflict, and the present invention is further described in detail with reference to the drawings and specific embodiments.

If directional indications (such as up, down, left, right, front, and rear … …) are provided in the embodiment of the present invention, the directional indications are only used to explain the relative position relationship between the components, the movement, etc. in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indications are changed accordingly.

In addition, the descriptions related to "first", "second", etc. in the present invention are only used for descriptive purposes and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature.

Referring to fig. 1 to 6, a series multi-pulse rectifier using a dc-side passive harmonic suppression method according to an embodiment of the present invention includes an input inductor 1, a phase-shifting transformer 2, a first three-phase full-bridge rectification circuit 3, a second three-phase full-bridge rectification circuit 4, a harmonic injection circuit 5, a first dc-side capacitor 6, a second dc-side capacitor 7, and a load 8.

The input inductor 1 is composed of three millihenry level inductors with the same size, harmonic components in input current of the rectifier can be ignored due to high impedance of the inductors to high-order current harmonics, the input current is equivalent to a sine wave, the left sides of the three input inductors are respectively connected with a three-phase alternating current power supply, and the right sides of the three input inductors are respectively connected with three taps of a primary winding of the isolation transformer.

The primary winding of the phase-shifting transformer 2 is connected in a triangular mode, the secondary winding of the phase-shifting transformer is connected in a star angle mode, three taps of the primary winding are connected with the right ends of three input inductors respectively, and the secondary winding of the phase-shifting transformer is connected with the input ends of two groups of three-phase full-bridge rectifying circuits respectively.

The first three-phase full-bridge rectification circuit 3 and the second three-phase full-bridge rectification circuit 4 are connected in series and connected in parallel with two direct-current side capacitors, and the output voltage of the rectifier is doubled. The harmonic injection circuit 5 is composed of a single-phase transformer and a single-phase full-bridge rectification circuit, the single-phase transformer is composed of a primary winding and a secondary winding, the left side of the primary winding is connected with the middle points of the two groups of three-phase full-bridge rectification circuits, the right side of the primary winding is connected with the middle points of the two direct-current side capacitors, the secondary winding is respectively connected with the input end of the single-phase full-bridge rectification circuit, the positive electrode of the output end of the single-phase full-bridge rectification circuit is connected with the negative electrode of the second three-phase full-. The invention adopts two groups of three-phase full-bridge rectification circuits for rectification, reduces the using amount of rectification devices in the main circuit and reduces the circuit loss.

The first direct current side capacitor 6 and the second direct current side capacitor 7 are connected in series, the positive pole of the capacitor 6 is connected with the positive pole of the first three-phase full-bridge rectifying circuit 3 and the positive pole of the load 8, the negative pole of the capacitor 6 is connected with the positive pole of the capacitor 7 and the middle points of the two groups of three-phase full-bridge rectifying circuits, and the negative pole of the capacitor 7 is connected with the negative pole of the second three-phase full-bridge rectifying circuit 4.

The principle of the series multi-pulse rectifier for suppressing the harmonic waves by using the direct current side passive harmonic suppression method provided by the embodiment of the invention is as follows: difference value of currents of two groups of three-phase full-bridge rectifying circuitsi _xThe frequency of the triangular wave is 6 times frequency,i _xafter flowing through the single-phase transformer, the primary winding of the single-phase transformer generates an injection voltage of 6 times frequency 3 step waves, and modulates the output voltage of the three-phase full-bridge rectification circuit, so that harmonic waves in the input voltage and current of the rectifier are eliminated.

The invention adopts two three-phase diode rectifier bridges for rectification, thereby reducing the using amount of rectifier devices in the main circuit and reducing the circuit loss; the direct current side can achieve similar harmonic suppression effect only by using one group of harmonic injection circuits, and the size and the cost of the circuit are effectively reduced.

Referring to fig. 1 and 2, as an embodiment, in the series multi-pulse rectifier using the dc side passive harmonic suppression method of the present invention, the isolation transformer 2 is composed of 3 identical core columns, each core column has 3 windings, including 1 primary winding and 2 secondary windings, and the turn ratio of the 3 windings is equal toN ₁:N ₂:N ₃=1.73:1.73: 1; winding a₁、a₂、a₃On the same core column, winding b₁、b₂、b₃On the same core column, winding c₁、c₂、c₃Are positioned on the same core column; primary winding a₁、b₁、c₁Form a triangular connection, and the positive ends of the triangular connection are respectively connected with point A, B, C; secondary winding a₂、b₂、c₂Form a triangular connection and are connected with a first single-phase full-bridge rectification circuit 3; secondary winding a₃、b₃、c₃Form a star connection and are connected with a second single-phase full-bridge rectifying circuit. The primary windings of the isolation transformer form a triangular connection, which is beneficial to improving the output power, and the secondary windings form a star connection and an angle connection, so that two groups of three-phase voltages with equal size and 30-degree phase difference are generated.

The embodiment adopts the isolated transformer, and the primary side and the secondary side of the transformer are electrically isolated, so that the transformer has higher safety.

As an embodiment, referring to fig. 1 and fig. 3, a transformer injected by a series multi-pulse rectifier using a dc-side passive harmonic suppression method according to the present invention is a single-phase transformer, the single-phase transformer is composed of 1 core column, the core column has 2 windings, a primary winding and a secondary winding, the left side of the input end of the single-phase transformer is connected to a connection point F of a rectifier bridge (i.e., a midpoint of two three-phase full-bridge rectification circuits), the right side of the input end of the injection transformer is connected to a connection point P of two dc-side capacitors, the secondary winding of the single-phase transformer is connected to the input end of the single-phase full-bridge rectification circuit, and the single-phase transformer and the single.

The single-phase transformer adopted by the embodiment has the advantages of simple structure, small capacity and low harmonic suppression cost.

As an embodiment, referring to fig. 1, 4, 5, and 6, the harmonic injection circuit 5 of the series multi-pulse rectifier using the dc side passive harmonic suppression method according to the present invention has the following operation modes:

the harmonic injection circuit 5 is composed of a single-phase transformer and a single-phase full-bridge rectification circuit, and can be known according to the structure of the transformer and the conduction mode of the rectification bridgei _xA triangular wave 6 times the power supply frequency; when in usei _x>At 0, diode D₁、D₄Conducting, diode D₂、D₃The power is turned off and the power is turned off,u _FP>0, the working mode I of the harmonic injection circuit 5 is shown in FIG. 4; when in usei _x<At 0, diode D₂、D₃Conducting, diode D₁、D₄The power is turned off and the power is turned off,u _FP<0, the working mode II of the harmonic injection circuit 5 is shown in FIG. 5; when in usei _xClose to 0, diode D₁、D₂、D₃、D₄All the components are conducted, and the power supply is turned on,u _FP=0, the harmonic injection circuit 5 operates in the mode III shown in fig. 6.

The harmonic injection circuit 5 is a current type harmonic injection circuit, the input electric energy quality of the rectifier is improved by injecting current harmonics to the direct current side of the rectifier, and the harmonic injection circuit 5 has a good harmonic suppression effect and stronger robustness.

The rectification sides of the harmonic injection circuit 5 are respectively connected with the load 8 and the negative pole of the second three-phase full-bridge rectification circuit 4, the current of the load 8 provides energy for the harmonic injection circuit 5, and the harmonic injection circuit 5 is higher in robustness.

The capacity of the harmonic injection circuit 5 of the invention is only 2.8 percent of the input power of the whole rectifier, and the loss is low.

As an embodiment, please refer to the figure1. FIG. 4, FIG. 5, and FIG. 6 show the turn ratio of the single-phase transformer of the series multi-pulse rectifier using the DC side passive harmonic suppression method of the present inventionN ₄/N ₅=1.2:1。

In one embodiment, the first three-phase full-bridge rectification circuit 3 and the second three-phase full-bridge rectification circuit 4 both use uncontrolled rectification devices, and reliability is high.

In one embodiment, the first dc-side capacitor 6 and the second dc-side capacitor 7 are two large capacitors with the same size, and the rectifier output voltage is filtered by the first dc-side capacitor 6 and the second dc-side capacitor 7 to be dc.

As an embodiment, the single-phase full-bridge rectification circuit is composed of four diodes (i.e. diode D in FIG. 1)₁、D₂、D₃、D₄) The single-phase full-bridge rectification circuit has the advantages of small current flowing through the single-phase full-bridge rectification circuit, small loss and high reliability.

The invention uses the direct current side passive harmonic suppression method to suppress the harmonic in the input voltage and current of the rectifier, compared with the rectifier without a harmonic injection circuit, the THD value of the input voltage is reduced from 12% to 4%, the input voltage of the rectifier conforms to the IEEE519-1992 standard, and the input electric energy quality of the rectifier is greatly improved.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.