In-phase power supply device, method and system for V / V transformer traction power supply system

Abstract

The present invention belongs to the field of power control technology, and specifically relates to a co-phase power supply device and a power supply method for a V / v transformer traction power supply system, aiming to solve the problems of large capacity and high cost of the existing V / v co-phase power supply device. The present invention comprises: a first transformer, a second transformer and a single-phase back-to-back converter; the first transformer and the second transformer are respectively connected to the two windings of the V / v transformer and connected through a common node; the first transformer and the second transformer are respectively connected to the single-phase back-to-back converter; the first output terminal of the single-phase back-to-back converter is connected to the power circuit through the first transformer, and the other end is directly connected to the power circuit. The present invention can realize the co-phase power supply of multiple traction substations by simply adding low-capacity single-phase power electronic equipment, while eliminating the negative sequence current problem in the existing power supply scheme, and improving the economy of the co-phase power supply technology.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric power control, and in particular relates to a same-phase power supply device, method and system for a V / V transformer traction power supply system. Background Art

[0002] The existing electrified railway traction power supply system usually uses a V / v transformer to convert three-phase AC into two single-phase AC, and then supplies power to the electric locomotive in a segmented and phased form. A non-conductive insulation area (neutral section) is usually set between different power supply sections. When the electric locomotive passes through this area, the electric locomotive cannot obtain power. In this process, the electric locomotive will lose traction and speed. The use of a V / v transformer will also generate a large amount of negative sequence current in the three-phase AC power grid, causing power imbalance in the power grid. At the same time, the negative sequence current problem will become more serious as the power of the electric locomotive increases.

[0003] The co-phase power supply converter based on power electronics technology can provide single-phase AC power supply to electric locomotives while ensuring that no negative sequence current is generated in the three-phase power grid. The capacity of the co-phase power supply converter described in Chinese invention patent CN201520230853.4 is equivalent to the capacity provided to the contact network by the traction substation, resulting in high cost of the converter. Chinese invention patent CN202110135799 uses a multi-winding transformer and a three-phase-single-phase AC-AC converter to achieve co-phase power supply. Although this solution can reduce the converter capacity on the output side of the three-phase-single-phase AC-AC converter, the three-phase input side still requires a large capacity to compensate for the negative sequence component, which is relatively expensive. Summary of the invention

[0004] In order to solve the above problems in the prior art, namely, the disadvantages of the existing V / v co-phase power supply device having large capacity and high cost, the present invention provides a co-phase power supply device for a V / v transformer traction power supply system, which is applied to a three-phase AC circuit with a V / v transformer, and the device comprises: a first transformer, a second transformer and a single-phase back-to-back converter;

[0005] The first transformer is connected to a first output winding of a V / v transformer via a first input connection terminal and a common connection terminal;

[0006] The second transformer is connected to the second output winding of the V / v transformer via the common connection terminal and the second input connection terminal;

[0007] One end of the output winding of the first transformer is connected to one end of the output winding of the second transformer;

[0008] The first input terminal of the single-phase back-to-back converter is connected to the first transformer, the second input terminal of the single-phase back-to-back converter is connected to the second transformer, the first output terminal of the single-phase back-to-back converter is connected to the first transformer, and the second output terminal of the single-phase back-to-back converter is connected to the power circuit;

[0009] The end of the output winding of the first transformer which is not connected to the second transformer is connected to the power circuit.

[0010] In some preferred embodiments, the first transformer has one winding on its input side and two windings on its output side, which are denoted as a first winding on the output side of the first transformer and a second winding on the output side of the first transformer.

[0011] In some preferred embodiments, the first input terminal T of the single-phase back-to-back converter b The first connection terminal T5 of the second winding on the output side of the first transformer is connected, the second connection terminal T6 of the second winding on the output side of the first transformer is connected to the first connection terminal T9 on the output side of the second transformer, and the second connection terminal T9 on the output side of the second transformer is connected. 10 The second input terminal T of the single-phase back-to-back converter a connected.

[0012] In some preferred embodiments, the first output terminal T of the single-phase back-to-back converter y The second connection terminal T4 of the first winding on the output side of the first transformer is connected, and the first connection terminal T3 of the first winding on the output side of the first transformer is connected to the power circuit; the second output terminal T x Connect the power circuit.

[0013] In some preferred embodiments, the V / v transformer is connected to the V / v transformer through the first input terminal T A , V / v transformer second input terminal T B and the third input terminal T of the V / v transformer C Access to three-phase AC power grid;

[0014] V / v transformer first output terminal T α Connecting to the first terminal T1 at the input side of the first transformer;

[0015] The first transformer input side second terminal T2 is connected to the second transformer input side first terminal T7 via the common node G. The second transformer input side second terminal T8 is connected to the V / V transformer third output terminal T β ;

[0016] The common node is connected to the second output terminal T of the V / V transformer n .

[0017] In some preferred embodiments, the first terminal T1 on the input side of the first transformer, the first connection terminal T3 on the first winding on the output side of the first transformer, and the first connection terminal T5 on the second winding on the output side of the first transformer are terminals of the same name;

[0018] The first terminal T7 at the input side of the second transformer and the first connection terminal T9 at the output side of the second transformer are terminals of the same name.

[0019] In some preferred embodiments, the single-phase back-to-back converter comprises 8N power modules PM, where N is a positive integer;

[0020] The first input terminal T of the single-phase back-to-back converter b , the second input terminal T of the single-phase back-to-back converter a The second output terminal T of the single-phase back-to-back converter is connected x and the first output terminal T of the single-phase back-to-back converter y An inductor L and N power modules PM are connected in series with the positive electrode P in sequence, and the connection method with the negative electrode N is the same as that of the positive electrode P.

[0021] In some preferred embodiments, the transformation ratio between the first transformer input side winding and the first transformer output side first winding is

[0022] The transformation ratio between the first transformer input side winding and the first transformer output side second winding is 2:1;

[0023] The transformation ratio between the second transformer input side winding and the second transformer output side winding is 1:1.

[0024] In another aspect of the present invention, a co-phase power supply method for a V / v transformer traction power supply system is provided, which is applied to a co-phase power supply device for a V / v transformer traction power supply system;

[0025] Through closed-loop control, the control current i inputted from the second input terminal of the single-phase back-to-back converter inputted by the second transformer is in is a sine wave, and the control current i in The voltage of the single-phase back-to-back converter is Keep the same phase;

[0026] Make the output voltage of the single-phase back-to-back converter The voltage of the first winding on the output side of the first transformer Maintain the same phase and the same amplitude;

[0027] The voltage of the first winding at the output side of the first transformer Input voltage of single-phase back-to-back converter The amplitudes are the same and the phases are 90° apart;

[0028] The device of the present application can be divided into the following two modules: 1. A two-phase voltage phase adjustment module implemented by a combination of the first and second transformers, which is used to adjust the two-phase voltage output by the V / V transformer with a phase difference of 60°. and Adjust to two-phase voltage with a phase difference of 90° and 2. The single-phase voltage phase adjustment module implemented by the single-phase back-to-back converter is used to adjust the input voltage of the single-phase back-to-back converter. Phase adjustment to The two-phase voltages adjusted by the above two modules are the same (i.e. the phase is adjusted by 90°), and the voltage amplitude does not change. and With the same amplitude and the same phase, and The railway traction system is powered by series access to the overhead line and rails.

[0029] A third aspect of the present invention provides a co-phase power supply system for a V / v transformer traction power supply system, applied to a three-phase AC circuit with a V / v transformer, the system comprising: a two-phase voltage phase adjustment module and a single-phase voltage phase adjustment module;

[0030] The two-phase voltage phase adjustment module is configured to be composed of a first transformer and a second transformer, and is used to adjust the two-phase voltage outputted by the V / V transformer with a phase difference of 60°. and Adjust to a two-phase voltage with a phase difference of 90°, that is, the input voltage of a single-phase back-to-back converter and the voltage of the first winding at the output side of the first transformer

[0031] The single-phase voltage phase adjustment module is configured to be composed of a single-phase back-to-back converter, and is used to adjust the input voltage of the single-phase back-to-back converter. The phase is adjusted to the voltage of the first winding on the output side of the first transformer The same, the output voltage with the same amplitude and phase and and will and Connect to the power circuit.

[0032] Beneficial effects of the present invention:

[0033] (1) The same-phase power supply device of the V / v transformer traction power supply system of the present application adjusts the two-phase voltage with a phase difference of 60° output by the V / v transformer to a two-phase voltage with a phase difference of 90° through the first and second transformers, thereby eliminating the negative sequence current problem existing in the existing power supply scheme. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0035] Figure 1 It is a same-phase power supply device of the V / v transformer traction power supply system of the present invention;

[0036] Figure 2 is a circuit schematic diagram of a single-phase back-to-back converter in an embodiment of the present invention; DETAILED DESCRIPTION

[0037] The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It is also necessary to explain that, for ease of description, only the parts related to the relevant invention are shown in the accompanying drawings.

[0038] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0039] The present invention provides a co-phase power supply device based on a V / v transformer traction power supply system. The device can realize co-phase power supply of multiple traction substations by simply adding low-capacity single-phase power electronic equipment, while eliminating the negative sequence current problem in the existing power supply scheme and improving the economy of the co-phase power supply technology. The converter capacity in the co-phase power supply scheme proposed by the present invention is only half of that of the traditional full-capacity converter, and the cost is lower.

[0040] A co-phase power supply device of a V / v transformer traction power supply system of the present invention is applied to a three-phase AC circuit with a V / v transformer, comprising: a first transformer, a second transformer and a single-phase back-to-back converter;

[0041] The first transformer is connected to a first output winding of a V / v transformer via a first input connection terminal and a common connection terminal;

[0042] The second transformer is connected to the second output winding of the V / v transformer via the common connection terminal and the second input connection terminal;

[0043] One end of the output winding of the first transformer is connected to one end of the output winding of the second transformer;

[0044] The first input terminal of the single-phase back-to-back converter is connected to the first transformer, the second input terminal of the single-phase back-to-back converter is connected to the second transformer, the first output terminal of the single-phase back-to-back converter is connected to the first transformer, and the second output terminal of the single-phase back-to-back converter is connected to the power circuit;

[0045] The end of the output winding of the first transformer which is not connected to the second transformer is connected to the power circuit.

[0046] In order to more clearly explain the same-phase power supply device of the V / V transformer traction power supply system of the present invention, Figure 1 Each component in the embodiment of the present invention is described in detail.

[0047] The same-phase power supply device of the V / V transformer traction power supply system of the first embodiment of the present invention comprises a first transformer, a second transformer and a single-phase back-to-back converter, and each component is described in detail as follows:

[0048] The first transformer is connected to a first output winding of a V / v transformer via a first input connection terminal and a common connection terminal;

[0049] In this embodiment, the first transformer has one winding on the input side and two windings on the output side, which are recorded as the first winding on the output side of the first transformer and the second winding on the output side of the first transformer. According to the specific application scenario, the number of windings can be increased and the corresponding transformation ratio can be obtained. This embodiment only takes one winding on the input side and two windings on the output side as an embodiment for easy understanding, and does not specifically limit the specific number of windings.

[0050] The second transformer is connected to the second output winding of the V / v transformer via the common connection terminal and the second input connection terminal;

[0051] One end of the output winding of the first transformer is connected to one end of the output winding of the second transformer;

[0052] In this embodiment, the V / v transformer is connected to the V / v transformer through the first input terminal T A , V / v transformer second input terminal T B and the third input terminal T of the V / v transformer C Access to three-phase AC power grid;

[0053] V / v transformer first output terminal T α Connecting to the first terminal T1 at the input side of the first transformer;

[0054] The first transformer input side second terminal T2 is connected to the second transformer input side first terminal T7 via the common node G. The second transformer input side second terminal T8 is connected to the V / V transformer third output terminal T β; That is, the input side of the first transformer is connected to the α output winding of the V / v transformer, and the input side of the second transformer is connected to the β output winding of the V / v transformer.

[0055] The common node is connected to the second output terminal T of the V / V transformer n .

[0056] The first input terminal of the single-phase back-to-back converter is connected to the first transformer, the second input terminal of the single-phase back-to-back converter is connected to the second transformer, the first output terminal of the single-phase back-to-back converter is connected to the first transformer, and the second output terminal of the single-phase back-to-back converter is connected to the power circuit;

[0057] In this embodiment, the first input terminal T of the single-phase back-to-back converter b The first connection terminal T5 of the second winding on the output side of the first transformer is connected, the second connection terminal T6 of the second winding on the output side of the first transformer is connected to the first connection terminal T9 on the output side of the second transformer, and the second connection terminal T9 on the output side of the second transformer is connected. 10 The second input terminal T of the single-phase back-to-back converter a connected.

[0058] In this embodiment, the first terminal T1 on the input side of the first transformer, the first connection terminal T3 on the first winding on the output side of the first transformer, and the first connection terminal T5 on the second winding on the output side of the first transformer are terminals of the same name;

[0059] The first terminal T7 at the input side of the second transformer and the first connection terminal T9 at the output side of the second transformer are terminals of the same name.

[0060] In this embodiment, the transformation ratio between the first transformer input side winding and the first transformer output side first winding is

[0061] The transformation ratio between the first transformer input side winding and the first transformer output side second winding is 2:1;

[0062] The transformation ratio between the second transformer input side winding and the second transformer output side winding is 1:1.

[0063] In this embodiment, the first output terminal T of the single-phase back-to-back converter y The second connection terminal T4 of the first winding on the output side of the first transformer is connected, and the first connection terminal T3 of the first winding on the output side of the first transformer is connected to the power circuit; the second output terminal T x Connect the power circuit. That is, T3 is connected to the traction power supply rail, T x Connected to the traction supply catenary.

[0064] In this embodiment, the single-phase back-to-back converter includes 8N power modules PM, where N is a positive integer; the power modules PM can be of board bridge or full bridge circuit topology. Figure 2 shown.

[0065] The first input terminal T of the single-phase back-to-back converter b , the second input terminal T of the single-phase back-to-back converter a The second output terminal T of the single-phase back-to-back converter is connected x and the first output terminal T of the single-phase back-to-back converter y An inductor L and N power modules PM are connected in series with the positive electrode P in sequence, and the connection method with the negative electrode N is the same as that of the positive electrode P.

[0066] The end of the output winding of the first transformer which is not connected to the second transformer is connected to the power circuit.

[0067] In the implementation scheme of the device of the present application, it is only necessary to adjust the phase of any one of the two-phase voltages with a phase difference of 90° through a power electronic transformer, so only low-capacity single-phase power electronic equipment is needed. In summary, while realizing the same-phase power supply technology, the present application reduces the impact of the traction locomotive on the power grid during operation and improves the economy of the same-phase power supply technology. In addition, the same-phase power supply device of the V / v transformer traction power supply system proposed in the present application can eliminate the negative sequence current without a complex power scheduling process, which greatly reduces the complexity.

[0068] The transformation ratio of the transformer designed in the present application enables the negative sequence current generated by the same-phase power supply device in the three-phase AC power grid to be eliminated without additional control.

[0069] The same-phase power supply method of the V / V transformer traction power supply system of the second embodiment of the present invention uses closed-loop control to make the control current i inputted from the second input terminal of the single-phase back-to-back converter inputted by the second transformer in is a sine wave, and the control current i in The voltage of the single-phase back-to-back converter is Keep the same phase;

[0070] In this embodiment, the function of the closed-loop control is to stabilize the voltage on the DC capacitor, stabilize the current phase on the input side of the single-phase back-to-back converter to be consistent with the input voltage phase, so as to achieve the effect of unity power factor control; stabilize the output voltage phase to be 90° different from the input phase.

[0071] Make the output voltage of the single-phase back-to-back converter The voltage of the first winding on the output side of the first transformer Maintain the same phase and the same amplitude;

[0072] The voltage of the first winding at the output side of the first transformer Input voltage of single-phase back-to-back converter The amplitudes are the same and the phases are 90° apart;

[0073] Provide power to the electrical circuit.

[0074] A third embodiment of the present invention discloses a co-phase power supply system of a V / v transformer traction power supply system, which is applied to a three-phase AC circuit with a V / v transformer, and is characterized in that the system comprises: a two-phase voltage phase adjustment module and a single-phase voltage phase adjustment module;

[0075] The two-phase voltage phase adjustment module is configured to be composed of a first transformer and a second transformer, and is used to adjust the two-phase voltage outputted by the V / V transformer with a phase difference of 60°. and Adjust to a two-phase voltage with a phase difference of 90°, that is, the input voltage of a single-phase back-to-back converter and the voltage of the first winding at the output side of the first transformer

[0076] The single-phase voltage phase adjustment module is configured to be composed of a single-phase back-to-back converter, and is used to adjust the input voltage of the single-phase back-to-back converter. The phase is adjusted to the voltage of the first winding on the output side of the first transformer The same, the output voltage with the same amplitude and phase and and will and Connect to the power circuit.

[0077] The same-phase power supply device and control method of the present invention enable the first winding of the first transformer to output a voltage and the output voltage of the single-phase back-to-back converter In phase, through and The series connection method makes the voltage phase between the contact network and the rail and The phases of the electric locomotives are the same. The voltage of the traction electric locomotive is effectively output between the contact network and the rail without generating negative sequence current on the grid side. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working process and related instructions of the system described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0078] The terms "first", "second", etc. are used to distinguish similar objects rather than to describe or indicate a particular order or sequence.

[0079] The term "comprise" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus / device that includes a list of elements includes not only those elements but also other elements not expressly listed, or also includes elements inherent to such process, method, article, or apparatus / device.

[0080] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A co-phase power supply device for a V / v transformer traction power supply system, applied to a three-phase AC circuit with a V / v transformer, characterized in that: The device comprises: a first transformer, a second transformer and a single-phase back-to-back converter; The first transformer is connected to a first output winding of a V / v transformer via a first input terminal and a common connection terminal; The second transformer is connected to the second output winding of the V / v transformer via the common connection terminal and the second input terminal; One end of the output winding of the first transformer is connected to one end of the output winding of the second transformer; The first input terminal of the single-phase back-to-back converter is connected to the first transformer, the second input terminal of the single-phase back-to-back converter is connected to the second transformer, the first output terminal of the single-phase back-to-back converter is connected to the first transformer, and the second output terminal of the single-phase back-to-back converter is connected to the power circuit; One end of the output winding of the first transformer which is not connected to the second transformer is connected to the power circuit; The first input terminal T of the single-phase back-to-back converter b The first connection terminal T5 of the second winding on the output side of the first transformer is connected, the second connection terminal T6 of the second winding on the output side of the first transformer is connected to the first connection terminal T9 on the output side of the second transformer, and the second connection terminal T9 on the output side of the second transformer is connected. 10 The second input terminal T of the single-phase back-to-back converter a connected; The first output terminal T of the single-phase back-to-back converter y The second connection terminal T4 of the first winding on the output side of the first transformer is connected, and the first connection terminal T3 of the first winding on the output side of the first transformer is connected to the power circuit; the second output terminal T x Connect the power circuit.

2. The same-phase power supply device of the V / V transformer traction power supply system according to claim 1 is characterized in that: The first transformer has one winding on its input side and two windings on its output side, which are denoted as a first winding on the output side of the first transformer and a second winding on the output side of the first transformer.

3. The same-phase power supply device of the V / V transformer traction power supply system according to claim 2, characterized in that: The V / v transformer passes through the first input terminal T of the V / v transformer A , V / v transformer second input terminal T B and the third input terminal T of the V / v transformer C Access to three-phase AC power grid; V / v transformer first output terminal T α Connecting to the first terminal T1 at the input side of the first transformer; The first transformer input side second terminal T2 is connected to the second transformer input side first terminal T7 via the common node G. The second transformer input side second terminal T8 is connected to the V / V transformer third output terminal T β ; The common node is connected to the second output terminal T of the V / V transformer n .

4. The same-phase power supply device of the V / V transformer traction power supply system according to claim 1, characterized in that: The first terminal T1 on the input side of the first transformer, the first connection terminal T3 on the first winding on the output side of the first transformer, and the first connection terminal T5 on the second winding on the output side of the first transformer are terminals of the same name; The first terminal T7 at the input side of the second transformer and the first connection terminal T9 at the output side of the second transformer are terminals of the same name.

5. The same-phase power supply device of the V / V transformer traction power supply system according to claim 1, characterized in that: The single-phase back-to-back converter comprises 8N power modules PM, where N is a positive integer; The first input terminal T of the single-phase back-to-back converter b , the second input terminal T of the single-phase back-to-back converter a The second output terminal T of the single-phase back-to-back converter is connected x and the first output terminal T of the single-phase back-to-back converter y An inductor L and N power modules PM are connected in series with the positive electrode P in sequence, and the connection method with the negative electrode N is the same as that of the positive electrode P.

6. The same-phase power supply device of the V / V transformer traction power supply system according to claim 1, characterized in that: The transformation ratio between the first transformer input side winding and the first transformer output side first winding is The transformation ratio between the first transformer input side winding and the first transformer output side second winding is 2:1; The transformation ratio between the input-side winding of the second transformer and the output-side winding of the second transformer is 1:

1.

7. A method for supplying power in phase of a V / v transformer traction power supply system, applied to a device for supplying power in phase of a V / v transformer traction power supply system according to any one of claims 1 to 6, characterized in that: Through closed-loop control, the control current i inputted from the second input terminal of the single-phase back-to-back converter inputted by the second transformer is in is a sine wave, and the control current i in The voltage of the single-phase back-to-back converter is Keep the same phase; Make the output voltage of the single-phase back-to-back converter The voltage of the first winding on the output side of the first transformer Maintain the same phase and the same amplitude; The voltage of the first winding at the output side of the first transformer Input voltage of single-phase back-to-back converter The amplitudes are the same and the phases are 90° apart; Provide power to the electrical circuit.

8. A system based on the same-phase power supply device of the V / v transformer traction power supply system according to any one of claims 1 to 6, applied to a three-phase AC circuit with a V / v transformer, characterized in that: The system comprises: a two-phase voltage phase adjustment module and a single-phase voltage phase adjustment module; The two-phase voltage phase adjustment module is configured to be composed of a first transformer and a second transformer, and is used to adjust the two-phase voltage outputted by the V / V transformer with a phase difference of 60°. and Adjust to a two-phase voltage with a phase difference of 90°, that is, the input voltage of a single-phase back-to-back converter and the voltage of the first winding at the output side of the first transformer The single-phase voltage phase adjustment module is configured to be composed of a single-phase back-to-back converter, and is used to adjust the input voltage of the single-phase back-to-back converter. The phase is adjusted to the voltage of the first winding on the output side of the first transformer The same, the output voltage with the same amplitude and phase and and will and Connect to the power circuit.

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