CN114290903A - Simplified design method of overvoltage protection resistor suitable for locomotive and motor car converter - Google Patents

Abstract

The invention relates to a model selection method of overvoltage protection resistors on a current transformer of an electric transmission system, in particular to a simplified design method of the overvoltage protection resistors suitable for a current transformer of a locomotive and a motor vehicle. The overvoltage protection resistor provides a simplified design idea of a single overvoltage protection resistor according to a simplified form of an application main circuit, reduces the type selection types and models, shortens the development period, improves the reliability of the resistor and simultaneously improves the operation stability of a converter system; the structural design of the single overvoltage protection resistor is beneficial to product integration and reduces the design complexity of the cabinet body; the overvoltage protection resistor small component is structurally designed, so that the cabinet body is convenient to arrange, install, repair and maintain.

Description

A simplified and unified design method of overvoltage protection resistor suitable for locomotive EMU converter

technical field

The invention relates to a type selection method of an overvoltage protection resistor on a converter of an electric drive system, in particular to a simplified and unified design method of an overvoltage protection resistor suitable for a locomotive motor train converter.

Background technique

With the rapid development of the railway industry, resistors, as important power components on the converter of the electric drive system, take on the role of consuming excess energy during the operation of the converter system. Among them, the overvoltage protection resistor is mainly used for the main circuit DC bus voltage higher than the set protection action value when the system has braking, idling, coasting, sudden load cut, network voltage distortion, etc. The instantaneous overvoltage energy in the circuit is released to eliminate the overvoltage. Overvoltage protection resistors are used as power devices to protect vehicle converters from being damaged by system overvoltage shocks. There has always been a problem in the selection and design of components that each type of resistor is specially designed. In the long run, the resistor components used in the locomotive and rolling stock converter system are cluttered and have poor interchangeability, which is not conducive to the modularization and generalization of the overall design of the train, and also increases the difficulty of converter production, inventory and maintenance.

Under normal circumstances, according to the system requirements of different models of converters, the selection of the electrical parameters of the overvoltage protection resistor and the selection of the structure type are carried out respectively. This method has the following disadvantages:

1. The main circuit topology of the locomotive EMU converter is different, and the electrical parameters are different. Therefore, there are many types and quantities of overvoltage protection resistors that have been selected, and the backlog of inventory in the factory is large, which is not conducive to product reuse;

2. The structure and size of the resistor vary greatly, and there are many types of installation interfaces. The installation position of the overvoltage protection resistor in the converter cabinet is not fixed, which is inconvenient for installation and is not conducive to troubleshooting and maintenance;

3. There are many types of overvoltage protection resistors, and each type of resistor designed needs to be type tested, which has low reliability and high product cost.

SUMMARY OF THE INVENTION

The invention provides a method for designing a single overvoltage protection resistor based on the simplification of rail transit converter components, which adopts a series-parallel single resistor structure combination, and is suitable for different voltage levels and topology circuits of high-power electric locomotives and motor trains , reduce the complexity of the selection and design of overvoltage protection resistors for converter applications, control design and production costs, and improve the availability of overvoltage protection resistors used in converter systems.

The present invention is realized by adopting the following technical solutions: a simplified and unified design method for overvoltage protection resistors suitable for locomotive motor train converters, according to the topology structure of the traction main circuit, the voltage level of the intermediate DC link, the shaft power, and the load of the IGBT device. The current bearing capacity, whether the auxiliary main circuit shares the intermediate circuit, and the auxiliary main circuit capacity, carry out the selection and calculation of the overvoltage protection resistor, and combine the actual application to use the single overvoltage protection resistor to simplify the design of the overvoltage protection resistor.

The above-mentioned simplified design method of overvoltage protection resistors suitable for locomotive motor train converters, the resistance value of overvoltage protection resistors is limited by the total power, voltage level and current carrying capacity of IGBT devices. The maximum and minimum boundary values are designed. The single overvoltage protection resistor meets the resistance calculation range.

The above-mentioned simplified design method of overvoltage protection resistors suitable for locomotive motor train converters, the energy and current carrying capacity that the single overvoltage protection resistor can withstand is limited, and the single overvoltage protection resistors are connected in series and parallel. Use in combination.

The above-mentioned simplified and unified design method of overvoltage protection resistors suitable for locomotive motor train converters. The series and parallel connection of single resistors of different specifications will cause the internal aging progress of the resistors to be unbalanced, and the resistors may be damaged. Use the same specifications of monomers The overvoltage protection resistors are connected in series and parallel to ensure symmetrical matching in structure to improve the reliability of the resistors.

The above-mentioned simplified and unified design method of an overvoltage protection resistor suitable for a locomotive motor train converter, and the final simplified and unified design of the overvoltage protection resistor is a single overvoltage protection resistor of 1.5Ω-150kJ specifications.

In the above-mentioned simplified design method of overvoltage protection resistors suitable for locomotive motor train converters, the single overvoltage protection resistors are of the open-exposed spiral belt structure type.

The above-mentioned simplified design method for overvoltage protection resistors suitable for locomotive motor train converters integrates overvoltage protection resistors on different traction shafts into one, and is fixedly installed in the converter cabinet in the form of small components.

The design and application of overvoltage protection resistors have the following beneficial effects:

1. Simplify the design of overvoltage protection resistors, reduce the types of resistors, shorten the development cycle, and reduce design costs;

2. Simplified and unified design of overvoltage protection resistors to improve the reliability of the resistors and improve the stability of the system;

3. The simplified and unified design of the overvoltage protection resistor is convenient for the interchangeable use of different project resistors and solves the problem of easy inventory backlog;

4. The structure design of the single overvoltage protection resistor improves the integration of the product and the compactness of the overall structure of the cabinet;

5. The structural design of the small components of the overvoltage protection resistor reduces the complexity of the cabinet design and facilitates the layout, installation and maintenance of the cabinet.

Description of drawings

Figure 1 is a schematic diagram of a single overvoltage protection resistor.

Figure 2 is a schematic diagram of a single overvoltage protection resistor composed of two series and two parallel 1.5Ω-600kJ resistors.

Figure 3 is a schematic diagram of a 6Ω-600kJ resistor composed of four strings of single overvoltage protection resistors.

Fig. 4 is the topological form diagram of the main circuit of the overvoltage protection resistor application.

Detailed ways

Simplified design of main circuit for overvoltage protection resistor application

The selection and calculation of the overvoltage protection resistor should consider the main circuit topology of the system, the voltage level of the intermediate DC link, the maximum power demand and the current carrying capacity of the IGBT device.

According to the application requirements of the electric drive system, the topological structure of the main circuit of the traction system is simplified into one-integrated one-inverse independent intermediate circuit, two-integrated two-inverse common intermediate circuit, two-integrated three-inverse common intermediate circuit, and three-integrated three-inverse common intermediate circuit four form. The topology of the main circuit of the auxiliary system is simplified into two forms: the secondary side of the transformer and the intermediate circuit. The main circuit form suitable for the overvoltage protection resistor after the simplified system is shown in Figure 4.

At present, the main circuit topology of the locomotive EMU converter simplifies the intermediate voltage level into two forms: 1800V and 3600V. Corresponding to the two intermediate voltage levels, the IGBT voltage levels in the system are 3300V and 6500V respectively, and the IGBTs are recommended to be 3300V/1500A and 6500V/750A.

According to the number of traction axles, axle load and axle power of electric locomotives and motor trains currently applied in the market, combined with factors such as low speed and heavy load, safety margin, and maximum running speed, the final axle power of the electric locomotive traction system is simplified as 1200kW, 1400kW, 1600kW, the shaft power of the motor vehicle traction system is simplified to 350kW, 650kW, the auxiliary converter of the 1200kW model has an auxiliary capacity of 180kVA, and the shaft power is greater than 1400kW. is 270kVA.

Simplified design method of overvoltage protection resistor

Comprehensive main circuit summary results: four types of traction main circuit topologies, five types of shaft power, two types of IGBTs, two cases of whether the auxiliary shares share the intermediate circuit, and two types of auxiliary capacity. The selection of overvoltage protection resistors is carried out under the arrangement and combination of the above conditions. Calculation, combined with practical application, the specifications and models of overvoltage protection resistors are complex and complicated, which is not easy to use and manage. It is necessary to simplify the design of overvoltage protection resistors. The present invention proposes a design idea of simplifying and unifying the overvoltage protection resistor by using a single overvoltage protection resistor, optimizes the design steps of type selection, and reduces the selection specifications and models.

1) Statistics of the existing project application resistance models, combined with electrical parameters and structural parameters analysis, the applicability of single resistors;

2) Simply using the calculated maximum energy resistance specification model as the simple choice of the single overvoltage protection resistor will easily cause the resistance to be large, the energy redundancy is too large, and the product cost will be increased accordingly;

3) The resistance value of the overvoltage protection resistor is limited by the total power, voltage level and IGBT current carrying capacity to limit the maximum and minimum boundary values. The designed single overvoltage protection resistor must meet the resistance calculation range;

4) The energy that a single resistor can withstand is limited, and the current carrying capacity is limited, so it can be considered for combined use in series and parallel;

5) The series and parallel connection of different specifications of monomer resistors will cause the internal aging progress of the resistance to be unbalanced, and the resistance may be damaged. In the design, the same monomer should be used in series and parallel to ensure symmetrical matching in structure to improve the reliability of the resistance.

Considering the above factors, combined with the results of the simplification of the main circuit, the final simplified design of the overvoltage protection resistor is a single 1.5Ω-150kJ specification model. According to the power requirements of different main circuit topologies of existing locomotives and motor vehicles, combined with the results of IGBT selection, the resistance value and energy requirements of different projects can be met through the series and parallel connection of single overvoltage protection resistors.

Simplified design of overvoltage protection resistor structure

At present, the resistors used in electric locomotives include square tube aluminum shell structure, round tube winding structure, open spiral belt structure, steel sheet structure, flat membrane structure, cylindrical membrane structure and other structural types. Due to the small size of square tube aluminum shell resistors and high protection level, the cost is high. Film resistors need to add radiators. Steel sheet resistors have large size and low reliability. It has advantages in terms of space and cost, and has been used in many projects in batches, so the simplified and unified single overvoltage protection resistor chooses the exposed spiral belt structure type.

The structure size of the 1.5Ω-150kJ single overvoltage protection resistor for the final simplified selection design is shown in Figure 1.

Single overvoltage protection resistors can be combined into different resistor models through series and parallel methods to meet the resistance requirements of different main circuits and projects. The structure of the resistor models combined in series and parallel is shown in Figure 2 and Figure 3.

In order to save space, the overvoltage protection resistors on different traction shafts are integrated in the overall design, and they are fixed in the form of small components and installed in the converter cabinet, which is convenient for the overall layout of the cabinet.

Specific implementation example

According to the principle that the short-term impact energy applied to the overvoltage protection resistor does not exceed the maximum impact energy that the resistor can withstand, the maximum resistance value of the overvoltage protection resistor is determined by the total power and voltage level of the intermediate links endured by the main circuit. The minimum resistance value of the overvoltage protection resistor is determined by the maximum current limit value that the IGBT can withstand. The single overvoltage protection resistors designed in a simple way are used in series and parallel to meet the requirements of each system project. The application of the single overvoltage protection resistors is shown in Table 1.

Table 1 Simple application of single overvoltage protection resistor

From Table 1, it can be seen that the 1.5Ω-150kJ single overvoltage protection resistor designed by the invention can be composed of 3Ω-300kJ and 1.5Ω-600kJ specification resistance types through 2 series and 2 parallel 2 series, which meets the resistance of the main circuit 1800V voltage level platform. According to the requirements, 4 resistors of 6Ω-600kJ are formed in series to meet the resistance requirements of the main circuit 3600V voltage level platform. Comparing the overvoltage protection resistor models and structures of the five projects that have been installed and operated, it can be seen from Table 1 that the designed 1.5Ω-150kJ single overvoltage protection resistors can be combined to replace the original application resistor models of the project. The single unit overvoltage protection resistor provides the possibility of interchangeability of products of different projects and enhances the utilization rate of the resistor.

When designing the cabinet, in order to improve the compactness of the cabinet installation, small components of overvoltage protection resistors are used to save space.

The overvoltage protection resistor for locomotive motor train converter is based on the simplified and unified form of the application main circuit, and the simplified and unified design idea of single overvoltage protection resistor is proposed to reduce the selection of types and models, shorten the development cycle, reduce the design cost, and improve the reliability of the resistor. At the same time, the operation stability of the converter system is improved; the structure design of the single overvoltage protection resistor is conducive to product integration and reduces the complexity of the cabinet design; the structure design of the overvoltage protection resistor small components is convenient for the layout, installation, maintenance and maintenance of the cabinet.

Claims (7)

1. A simplified design method of an overvoltage protection resistor suitable for a locomotive and motor car converter is characterized by comprising the following steps: and performing overvoltage protection resistance type selection calculation according to the topological structure of the traction main circuit, the voltage grade of the intermediate direct-current link, the shaft power, the current-carrying bearing capacity of the IGBT device, whether the auxiliary main circuit shares the intermediate circuit and the capacity of the auxiliary main circuit, and performing simplified design of the overvoltage protection resistance by using the single overvoltage protection resistance in combination with practical application.

2. The method for designing the overvoltage protection resistor in a simplified manner, which is suitable for a locomotive and motor vehicle converter, according to claim 1, is characterized in that: the resistance value of the overvoltage protection resistor is limited to the maximum and minimum boundary values by the total power, the voltage grade and the current carrying bearing capacity of the IGBT device, and the designed single overvoltage protection resistor meets the resistance value calculation range.

3. The method for designing the overvoltage protection resistor in a simplified manner for the current transformer of the locomotive and motor vehicle according to claim 2, wherein the method comprises the following steps: the single overvoltage protection resistor is limited in energy and current carrying capacity, and is used in combination in series and parallel.

4. The method for designing the overvoltage protection resistor in a simplified manner for the current transformer of the locomotive and motor vehicle according to claim 3, wherein the method comprises the following steps: the resistor internal aging progress is unbalanced due to the fact that the resistor single resistors of different specifications are connected in series and in parallel, the resistor is likely to be damaged, series and parallel connection is conducted through the same specification of single overvoltage protection resistors, structural symmetrical matching is guaranteed, and the reliability of the resistor is improved.

5. The method for designing the overvoltage protection resistor in a simplified manner for the current transformer of the locomotive and motor vehicle according to claim 4, wherein the method comprises the following steps: finally, the overvoltage protection resistor is designed to be a single overvoltage protection resistor with the specification and model number of 1.5 omega-150 kJ in a simplified mode.

6. The method for designing the overvoltage protection resistor in a simplified manner for the current transformer of the locomotive and motor vehicle according to claim 5, wherein the method comprises the following steps: the single overvoltage protection resistor is in an open type spiral belt structure type.

7. The simplified design method of the overvoltage protection resistor suitable for the locomotive motor vehicle converter according to claim 4 or 5, characterized in that: overvoltage protection resistors on different traction shafts are integrated into a whole and fixedly arranged in the converter cabinet body in a small assembly mode.

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