CN104485213B - A DC Saturated Reactor for Reducing Thyristor Voltage Resistance - Google Patents

Abstract

The present invention relates to a kind of reduce the direct-curent saturable reactor that IGCT is pressure.The closed loop iron core that it uses at least two sectional areas are equal, all have the iron core column of DC coil and AC coil, and these two iron core column the most at least can form a magnetic flux closed loop without the other side's iron core column；Between AC coil or each AC coil is connected at least one resistance with the ac circuit between neutral point；At least two DC coils connect respective forward commutation diode and reverse commutation diode respectively；Each commutation diode reversely IGCT the most in parallel, thyristor control end connects control circuit；Control circuit controls the size at IGBT group angle, by continuously adjusting the size at each IGBT group angle, controls the size of DC current in the DC coil being connected with commutation diode, it is achieved control the size of direct-curent saturable reactor reactance value.

Description

A DC Saturated Reactor for Reducing Thyristor Voltage Resistance

technical field

The invention relates to the technical field of power transmission and transformation in power systems, in particular to a DC saturated reactor for reducing the withstand voltage of a thyristor.

Background technique

Reactors are widely used in power systems. The series reactor can limit the short-circuit current; the shunt reactor can limit the overvoltage; the combination of the reactor and the capacitor can form a filter circuit. In some application fields, the reactance value of the reactor is fixed; in some application fields, the reactance value of the reactor should be adjusted continuously with the change of the power system operation mode. The controllable saturable reactor (abbreviated as: saturable reactor) whose reactance value can be adjusted continuously is an important research topic.

The saturable reactor uses the saturation characteristics of the closed-loop iron core of the saturable reactor to change the reactance value of the reactor. Many saturable reactors have been proposed. In 2008, China Water Conservancy and Hydropower Press published Cai Xuansan and Gao Yuenong's book "Controllable Saturable Reactor Principles, Design and Application" to summarize the saturable reactor. However, the existing DC saturable reactor generally has the problem of slow response speed. CN2014104617822.4 and CN2014104617822.4 propose the measure of series resistance, which improves the reaction speed of DC saturated reactor. However, the series resistance increases the voltage at both ends of the thyristor, and the thyristor has a high withstand voltage requirement.

Contents of the invention

The object of the present invention is to solve the above problems and provide a DC saturated reactor that reduces the withstand voltage of the thyristor.

To achieve the above object, the present invention adopts the following methods:

A DC saturated reactor for reducing the withstand voltage of a thyristor, including a DC saturated reactor; the DC saturated reactor adopts a closed-loop iron core, and the closed-loop iron core has at least two equal cross-sectional areas, each of which has a DC coil and an AC coil The two iron core columns each have at least one magnetic flux closed loop that does not pass through the other iron core column;

A group of AC coils and DC coils of the two iron core columns are connected together, and the remaining group of AC coils and DC coils are connected together;

The AC coils of the different iron core columns are connected in series in forward direction, and at least one resistor is connected in the AC loop of the series AC coils;

The DC coil and the AC coil of the same core column are respectively connected with respective forward rectification diodes and reverse rectification diodes;

Reverse thyristors are connected in parallel with each rectifier diode, and the control terminal of the thyristors is connected to the control circuit;

The control circuit controls the firing angle of the thyristors. By continuously adjusting the firing angles of each thyristor, the magnitude of the DC current in the DC coil connected to the rectifier diode is controlled to realize the control of the reactance value of the DC saturated reactor.

A DC saturated reactor for reducing the withstand voltage of a thyristor, including a DC saturated reactor; the DC saturated reactor adopts a closed-loop iron core, and the closed-loop iron core has at least two equal cross-sectional areas, each of which has a DC coil and an AC coil The two iron core columns each have at least one magnetic flux closed loop that does not pass through the other iron core column;

The ends of the AC coils and DC coils with the same name are connected together;

The remaining terminals of each AC coil are connected through their respective resistors, and each DC coil is connected together through their respective forward rectifier diodes and reverse rectifier diodes;

The respective rectifier diodes are respectively connected in parallel with corresponding reverse thyristors;

The control terminals of the thyristors are connected to the control circuit;

The control circuit controls the firing angle of the thyristors. By continuously adjusting the firing angles of each thyristor, the magnitude of the DC current in the DC coil connected to the rectifier diode is controlled to realize the control of the reactance value of the DC saturated reactor.

A DC saturated reactor for reducing the withstand voltage of a thyristor, including a DC saturated reactor; the DC saturated reactor adopts a closed-loop iron core, and the closed-loop iron core has at least two iron core columns with equal cross-sectional areas, and the two Each iron core column has at least one magnetic flux closed loop that does not pass through the other iron core column;

A first AC coil, a second AC coil and a DC coil are respectively arranged on each iron core column;

Wherein, the same-named ends of the first AC coils and the same-named ends of each DC coil are connected together;

The opposite end of the first AC coil of each iron core column is connected to the same end of the second AC coil of the other iron core column;

The opposite ends of each second AC coil are respectively connected through their respective resistors, and the opposite ends of each DC coil are connected together through their respective forward rectifying diodes and reverse rectifying diodes;

At the same time, each rectifier diode is also connected in parallel with a corresponding reverse thyristor;

The control terminals of the thyristors are connected to the control circuit;

The control circuit controls the firing angle of the thyristors. By continuously adjusting the firing angles of each thyristor, the magnitude of the DC current in the DC coil connected to the rectifier diode is controlled to realize the control of the reactance value of the DC saturated reactor.

The turns of the AC coils are the same; the turns of the DC coils are the same.

The number of turns of the AC coil is 1/2 of the number of turns of the primary coil of the transformer with the same rated voltage level as the DC saturated reactor.

The control circuit continuously controls the size of the firing angle of the two thyristors, and can continuously control the size of the DC current in each DC coil to realize continuous adjustment of the reactance value of the DC saturated reactor, and the reactance value of the DC saturated reactor is between the maximum value and the minimum value. Adjust and change between.

The beneficial effect of the invention is that the voltage at both ends of the rectifier diode and the thyristor can be reduced, and the requirements for the withstand voltage of the rectifier diode and the thyristor are low, which is economical. During the change process of the thyristor firing angle, the change of the DC coil current is smooth, and the generated harmonics are small; the impact on the thyristor is small, and the generated interference is small. The method is simple and reliable.

Description of drawings

Figure 1 shows the first DC saturated reactor.

Figure 2 shows the second DC saturated reactor.

Figure 3 shows the third DC saturated reactor.

Among them, 1. DC saturated reactor terminal I, 2. DC saturated reactor terminal II, 3. DC saturated reactor core, 4. Control circuit.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Example 1:

The structure and connection method of the first DC saturable reactor that reduces the withstand voltage of the thyristor are shown in Figure 1. Including DC saturated reactor terminal I1, DC saturated reactor terminal II2, DC saturated reactor closed-loop iron core 3, control circuit 4. The closed-loop iron core 3 of the DC saturated reactor has at least two iron core columns; there are two iron core columns with the same cross-sectional area, both of which have DC coils and AC coils. Closed loop of magnetic flux in the core leg. There are AC coil L1 and DC coil L2 on one of the iron core columns, and there are AC coil terminal L3 and DC coil L4 on the other iron core column; the number of turns of AC coil L1 and AC coil L3 is equal; DC coil L2, DC The number of turns of the coil L4 is equal. For most applications, it is recommended that the number of turns of the AC coil L1 and the DC coil L2 be equal, and the number of turns of the AC coil L1 is 1/2 of the number of turns of the primary coil of the transformer with the same rated voltage level as the DC saturated reactor.

The iron core 3 of the DC saturated reactor can be two closed-loop iron cores that have no path to each other, for example 1: two zigzag iron cores. It can also be an integrated closed-loop iron core with mutual passages; for example 2: three iron core columns, and there are yokes at both ends of the iron core columns to connect the three iron core columns. Any two iron core columns can form a magnetic flux closed loop with each other. But there are at least two of them that can respectively form closed loops that do not pass through each other's iron core columns. For example 3: There are four iron core columns, and there are yokes at both ends of the iron core columns to connect the four iron core columns. Any two iron core columns can form a closed magnetic flux loop with each other, but at least two of them can form a magnetic flux loop without passing through each other. The closed loop of the stem is shown in Figure 1.

After the same-named end of the AC coil L1 is connected with the same-named end of the DC coil L4, connect to terminal I1; after connecting the different-named end of the DC coil L2 and the different-named end of the AC coil L3, connect to terminal II2. The different end of the AC coil L1 is connected in series with the resistor R1, and then connected to the same end of the AC coil L3; the different end of the AC coil L1 is connected to the same end of the DC coil L2 through the forward rectification diode D1; the same end of the AC coil L3 is connected through the forward rectification diode D2 The DC coil L4 has a different name terminal; the rectifier diode D1 is connected in parallel with a reverse thyristor D3, and the rectifier diode D2 is connected in parallel with a reverse thyristor D4; the trigger terminals of the thyristor D3 and the thyristor D4 are respectively connected with the control circuit 4, and the control circuit 4 controls the thyristor D3 and the thyristor D4 The size of the firing angle.

Suppose the rated voltage of the first type of DC saturated reactor is U1, and the first type of DC saturated reactor is connected to the system with the rated voltage of U1. When the control circuit 4 controls the thyristor D3 and the thyristor D4 to be fully turned on, the rectifier diode D1 and the rectifier diode D2 have no rectification function, and the DC current in the DC coil L2 and the DC coil L4 is equal to zero. The reactance value of the DC saturated reactor is the maximum value.

When the control circuit 4 controls the thyristor D3 and the thyristor D4 to be fully cut off, the rectifier diode D1 and the rectifier diode D2 have a rectification function, and the DC current flowing through the DC coil L2 and the DC coil L4 reaches the maximum design value. The reactance value of the DC saturated reactor is the minimum value.

The control circuit 4 controls the size of the firing angle of the thyristor D3 and the thyristor D4, and can control the size of the DC current in the DC coil L2 and the DC coil L4, so as to realize the control of the reactance value of the DC saturated reactor. The control circuit 4 continuously controls the size of the firing angle of the thyristor D3 and the thyristor D4, and can continuously control the size of the DC current in the DC coil L2 and the DC coil L4 to realize continuous adjustment of the reactance value of the DC saturated reactor. The reactance value of the DC saturated reactor is at the maximum Adjust and change between the value and the minimum value.

Experiments show that: rectifier diode D1 and thyristor D3 are connected in reverse parallel, which can reduce the voltage across rectifier diode D1 and thyristor D3; rectifier diode D2 and thyristor D4 are connected in reverse parallel, which can reduce the voltage across rectifier diode D2 and thyristor D4, and the Diodes and thyristors have low withstand voltage requirements and are economical. During the turn-on and turn-off process of the thyristor D3 and the thyristor D4, or the change process of the trigger angle of the thyristor, the change of the DC coil current is smooth, and the generated harmonic is small; the impact on the thyristor is small, and the generated interference is small.

It can be seen that the thyristor D3 and the thyristor D4 can be replaced by fully controlled power electronic devices respectively. For example: thyristor D3 and thyristor D4 can be replaced by IGBT devices respectively, so as to obtain better control characteristics. The control method of the IGBT device is public knowledge and will not be repeated here.

Example 2:

The structure and connection method of the second DC saturated reactor that reduces the withstand voltage of the thyristor is shown in Figure 2. Including DC saturated reactor terminal I1, DC saturated reactor terminal II2, DC saturated reactor closed-loop iron core 3, control circuit 4. The closed-loop iron core 3 of the DC saturated reactor has at least two iron core columns; there are two iron core columns with the same cross-sectional area, both of which have DC coils and AC coils. Closed loop of magnetic flux in the core leg. There is an AC coil L5 and a DC coil L6 on one of the iron core columns, and an AC coil L7 and a DC coil L8 on the other iron core column; the number of turns of the AC coil L5 and the AC coil L7 is equal; the DC coil L6 and the DC coil The number of turns of L8 is equal. For most applications, it is recommended that the number of turns of the AC coil L5 and the DC coil L6 be equal, and the number of turns of the AC coil L5 be the same as that of the primary coil of the transformer with the same rated voltage level as the DC saturated reactor.

The same-named end of the AC coil L5, the same-named end of the DC coil L6, the same-named end of the AC coil L7, and the same-named end of the DC coil L8 are connected to the terminal I1. The remaining terminals of AC coil L5 are connected to terminal II2 through resistor R3, the remaining terminals of AC coil L7 are connected to terminal II2 through resistor R4, the remaining terminals of DC coil L6 are connected to terminal II2 through forward rectifying diode D5, and the remaining terminals of DC coil L8 are connected to terminal II2 through reverse rectifying diode D6 Connect terminal II2. The rectifier diode D5 is connected in parallel with a reverse thyristor D7, and the rectifier diode D6 is connected in parallel with a reverse thyristor D8; the trigger terminals of the thyristor D7 and the thyristor D8 are respectively connected to the control circuit 4, and the control circuit 4 controls the size of the trigger angles of the thyristor D7 and the thyristor D8.

Suppose the rated voltage of the first type of DC saturated reactor is U1, and the first type of DC saturated reactor is connected to the system with the rated voltage of U1. When the control circuit 4 controls the thyristor D7 and the thyristor D8 to be fully turned on, the rectifier diode D5 and the rectifier diode D6 have no rectification function, and the DC current in the DC coil L6 and the DC coil L8 is equal to zero. The reactance value of the DC saturated reactor is the maximum value.

When the control circuit 4 controls the thyristor D7 and the thyristor D8 to be completely cut off, the rectifier diode D5 and the rectifier diode D6 have a rectification function, and the DC current flowing through the DC coil L6 and the DC coil L8 reaches the maximum design value. The reactance value of the DC saturated reactor is the minimum value.

The control circuit 4 controls the size of the firing angle of the thyristor D7 and the thyristor D8, can control the size of the DC current in the DC coil L6 and the DC coil L8, and realizes the control of the reactance value of the DC saturated reactor. The control circuit 4 continuously controls the size of the firing angle of the thyristor D7 and the thyristor D8, and can continuously control the size of the DC current in the DC coil L7 and the DC coil L8 to realize continuous adjustment of the reactance value of the DC saturated reactor. The reactance value of the DC saturated reactor is at the maximum Adjust and change between the value and the minimum value.

The parts that are the same as those in Embodiment 1 will not be repeated here.

Example 3:

The structure and connection method of the third DC saturated reactor that reduces the withstand voltage of the thyristor is shown in Figure 3. Including DC saturated reactor terminal I1, DC saturated reactor terminal II2, DC saturated reactor closed-loop iron core 3, control circuit 4. The closed-loop iron core 3 of the DC saturated reactor has at least two iron core columns; there are two iron core columns with the same cross-sectional area, both of which have DC coils and AC coils. Closed loop of magnetic flux in the core leg. One of the core columns has AC coil L9(1), AC coil L9(2) and DC coil L10; the other core column has AC coil L11(1), AC coil L11(2) and DC coil L12; AC coil L9(1), AC coil L9(2), AC coil L11(1), AC coil L11(2) have the same number of turns, and DC coil L10 and DC coil L12 have the same number of turns. For most applications, it is recommended that the number of turns of the AC coil L9(1) be 1/2 of the number of turns of the DC coil L10, and the number of turns of the AC coil L9(1) be 1/2 of the number of turns of the primary coil of a transformer with the same rated voltage level as the DC saturated reactor 2.

The AC coil L9 (1) has the same name end, the DC coil L10 has the same name end, the AC coil L11 (1) has the same name end, and the DC coil L12 has the same name end connected to the terminal I1. The opposite end of AC coil L9 (1) is connected to the same end of AC coil L11 (2), and the opposite end of AC coil L11 (1) is connected to the same end of AC coil L9 (2); the remaining terminals of AC coil L9 (2) are connected through resistor R5 Terminal II2, the remaining terminals of the AC coil L11 (2) are connected to the terminal II2 through the resistor R6, the remaining terminals of the DC coil L10 are connected to the terminal II2 through the forward rectification diode D9, and the remaining terminals of the DC coil L12 are connected to the terminal II2 through the reverse rectification diode D10. The rectifier diode D9 is connected in parallel with a reverse thyristor D11, and the rectifier diode D10 is connected in parallel with a reverse thyristor D12. The trigger terminals of the thyristor D11 and the thyristor D12 are respectively connected to the control circuit 4, and the control circuit 4 controls the size of the trigger angle of the thyristor D11 and the thyristor D12.

Suppose the rated voltage of the first type of DC saturated reactor is U1, and the first type of DC saturated reactor is connected to the system with the rated voltage of U1. When the control circuit 4 controls the thyristor D11 and the thyristor D12 to be fully turned on, the rectifier diode D9 and the rectifier diode D10 have no rectification function, and the DC current in the DC coil L10 and the DC coil L12 is equal to zero. The reactance value of the DC saturated reactor is the maximum value.

When the control circuit 4 controls the thyristor D11 and the thyristor D12 to be fully cut off, the rectifier diode D9 and the rectifier diode D10 have a rectification function, and the DC current flowing through the DC coil L10 and the DC coil L12 reaches the maximum design value. The reactance value of the DC saturated reactor is the minimum value.

The control circuit 4 controls the size of the firing angle of the thyristor D11 and the thyristor D12, and can control the size of the DC current in the DC coil L10 and the DC coil L12, so as to realize the control of the reactance value of the DC saturated reactor. The control circuit 4 continuously controls the size of the firing angle of the thyristor D11 and the thyristor D12, and can continuously control the magnitude of the DC current in the DC coil L10 and the DC coil L12 to realize continuous adjustment of the reactance value of the DC saturated reactor. The reactance value of the DC saturated reactor is at the maximum Adjust and change between the value and the minimum value.

The parts that are the same as those in Embodiment 1 will not be repeated here.

The DC saturated reactor for reducing the voltage resistance of the thyristor of the present invention can be designed and manufactured by the prior art, can be completely realized, and has broad application prospects.

Claims (6)

1. A DC saturated reactor that reduces the voltage resistance of thyristors is characterized in that it includes a DC saturated reactor; the DC saturated reactor adopts a closed-loop iron core, and the closed-loop iron core has at least two equal cross-sectional areas, There are iron core columns of DC coil and AC coil, each of these two iron core columns can form at least one magnetic flux closed loop that does not pass through the other iron core column; A group of AC coils and DC coils of the two iron core columns are connected together, and the remaining group of AC coils and DC coils are connected together; The AC coils of the different iron core columns are connected in series in forward direction, and at least one resistor is connected in the AC loop of the series AC coils; The DC coil and the AC coil of the same core column are respectively connected with respective forward rectification diodes and reverse rectification diodes; Reverse thyristors are connected in parallel with each rectifier diode, and the control terminal of the thyristors is connected to the control circuit; The control circuit controls the firing angle of the thyristors. By continuously adjusting the firing angles of each thyristor, the magnitude of the DC current in the DC coil connected to the rectifier diode is controlled to realize the control of the reactance value of the DC saturated reactor; when the control circuit controls both When conducting, the two rectifier diodes have no rectification effect, the DC current in each DC coil is equal to zero, and the reactance value of the DC saturated reactor is the maximum value; When the control circuit controls the two thyristors to be fully cut off, the two rectifier diodes have a rectifying effect, the DC current flowing through each DC coil reaches the maximum design value, and the reactance value of the DC saturated reactor is the minimum value. 2. A DC saturated reactor that reduces the thyristor withstand voltage is characterized in that it includes a DC saturated reactor; the DC saturated reactor adopts a closed-loop iron core, and the closed-loop iron core has at least two equal cross-sectional areas, There are iron core columns of DC coil and AC coil, each of these two iron core columns can form at least one magnetic flux closed loop that does not pass through the other iron core column; The ends of the AC coils and DC coils with the same name are connected together; The remaining terminals of each AC coil are connected through their respective resistors, and each DC coil is connected together through their respective forward rectifier diodes and reverse rectifier diodes; The respective rectifier diodes are respectively connected in parallel with corresponding reverse thyristors; The control terminals of the thyristors are connected to the control circuit; The control circuit controls the size of the firing angle of the thyristor, and controls the size of the DC current in the DC coil connected to the rectifier diode by continuously adjusting the size of the firing angle of each thyristor, so as to realize the control of the reactance value of the DC saturated reactor; When the control circuit controls the two thyristors to be fully turned on, the two rectifier diodes have no rectification effect, the DC current in each DC coil is equal to zero, and the reactance value of the DC saturated reactor is the maximum value; When the control circuit controls the two thyristors to be fully cut off, the two rectifier diodes have a rectifying effect, the DC current flowing through each DC coil reaches the maximum design value, and the reactance value of the DC saturated reactor is the minimum value. 3. A DC saturated reactor that reduces the withstand voltage of the thyristor is characterized in that it includes a DC saturated reactor; the DC saturated reactor adopts a closed-loop iron core, and the closed-loop iron core has at least two equal cross-sectional areas Iron core columns, each of these two iron core columns can at least form a closed loop of magnetic flux that does not pass through the other iron core column; A first AC coil, a second AC coil and a DC coil are respectively arranged on each iron core column; Wherein, the same-named ends of the first AC coils and the same-named ends of each DC coil are connected together; The opposite end of the first AC coil of each iron core column is connected to the same end of the second AC coil of the other iron core column; The opposite ends of each second AC coil are respectively connected through their respective resistors, and the opposite ends of each DC coil are connected together through their respective forward rectifying diodes and reverse rectifying diodes; At the same time, each rectifier diode is also connected in parallel with a corresponding reverse thyristor; The control terminals of the thyristors are connected to the control circuit; The control circuit controls the size of the firing angle of the thyristor, and controls the size of the DC current in the DC coil connected to the rectifier diode by continuously adjusting the size of the firing angle of each thyristor, so as to realize the control of the reactance value of the DC saturated reactor; When the control circuit controls the two thyristors to be fully turned on, the two rectifier diodes have no rectification effect, the DC current in each DC coil is equal to zero, and the reactance value of the DC saturated reactor is the maximum value; When the control circuit controls the two thyristors to be fully cut off, the two rectifier diodes have a rectifying effect, the DC current flowing through each DC coil reaches the maximum design value, and the reactance value of the DC saturated reactor is the minimum value. 4. The DC saturated reactor for reducing the withstand voltage of thyristors according to claim 1, 2 or 3, wherein the number of turns of each of the AC coils is the same; the number of turns of each of the DC coils is the same. 5. The DC saturated reactor for reducing thyristor withstand voltage as claimed in claim 1, 2 or 3, wherein the number of turns of the AC coil is the number of turns of the transformer primary coil of the same rated voltage level of the DC saturated reactor 1/2 of. 6. The DC saturated reactor for reducing the thyristor withstand voltage as claimed in claim 1, 2 or 3, wherein the control circuit continuously controls the firing angle of the two thyristors, and can continuously control the firing angle of each DC coil. The magnitude of the DC current realizes the continuous adjustment of the reactance value of the DC saturated reactor, and the reactance value of the DC saturated reactor is adjusted and changed between the maximum value and the minimum value.