CN204578377U - A kind of cascade-mixing transformation apparatus in parallel - Google Patents

Abstract

The utility model discloses a cascade-parallel hybrid converter device, which is provided with energy by a three-phase power supply, divides the power supply into three phases through a split transformer, and divides the voltage of each phase of the secondary winding into several independent Low voltage, these independent voltages pass through single-phase-single-phase converters respectively, and form single-phase AC output voltage through cascading. The cascaded outputs of each phase are respectively connected in parallel and then connected to the load through an LC filter circuit to form a three-phase-single-phase converter. The power unit module is a single-phase-single-phase PWM converter, and the converter may have a two-level structure or a multi-level structure. The topology structure of the utility model can make the low-voltage device be applied to the high-voltage occasion, realize the output of the inverter at a higher voltage level, and increase or decrease the cascaded and parallel units to meet different design requirements. The output end can be connected to the load and can be regarded as a three-phase single-phase converter; the utility model can also be applied in the same phase power supply system of the electrified railway, the output end can supply power for the traction network, and provide energy for the three-phase power supply A, B, The three phases of C can jointly share the power required by the load or traction network, and the energy can flow in both directions.

Description

A Cascade-Parallel Hybrid Converter Device

technical field

The utility model relates to a cascade-parallel hybrid converter device, in particular to a cascade-parallel hybrid converter device for electrified railways.

Background technique

The converter converts electric energy through power electronic technology. It uses thyristor circuits to convert various AC or DC power inputs into AC outputs with the required output voltage and frequency stability. Today's rapid development in the fields of power systems, battery backup power supply systems, etc. has also prompted the rapid development of large-capacity converters, and the use of high-power converters is also becoming more and more extensive. The same is true for electrified railway design, which needs to output a power supply with sufficient power on the inverter side for the smooth operation of the locomotive. Converters used in electrified railways have very strict output power requirements. How to simultaneously increase the capacity of converters and improve the quality of output power is an important development direction of modern inverter technology. Therefore, it is of great research significance to study the circuit topology of high-power converters, so as to increase the capacity of power electronic converters and improve the quality of their output power.

The cascading of converters has the characteristics of series connection, which can provide input from smaller power modules to achieve high-voltage and high-power output, and realize the function of applying low-voltage devices to high-voltage occasions and the converter outputs at a higher voltage level. The parallel operation of converters can not only realize power synthesis, increase the level of output current, meet the requirements of high current level output of the converter system, increase the capacity of power supply, but also improve the reliability of power supply.

In the design of electrified railways, the output voltage of the power supply system can only reach 27.5kv. If it is necessary to continue to increase the output capacity of the converter, it is meaningless to continue to increase the cascade units. At this time, you can consider adding parallel connections to increase the output current. Further increase the converter capacity.

Utility model content

The purpose of this utility model is to provide a cascade-parallel hybrid converter topology, which has a flexible control mode, and the phase and amplitude of the output voltage can be adjusted and controlled according to the needs of the equipment, and can be adjusted according to the actual needs of the project. The expansion of the converter unit, and the output voltage has low harmonic content, the converter has high working efficiency, and is suitable for high-voltage and high-power output.

The utility model solves its technical problems, and the adopted technical scheme is:

A cascade-parallel hybrid converter device, which is powered by a three-phase power supply, and the power supply is divided into three phases through a transformer, and the voltage of each phase of the secondary winding is cut into several independent low voltages, and these independent voltages are respectively Through the single-phase-single-phase converter, the single-phase AC output voltage is formed by cascading; and the cascaded output of each phase is connected in parallel and then connected to the load through the LC filter circuit to form a three-phase-single-phase converter. The specific connection method is as follows: :

a. The primary side winding of the split transformer is connected to the three-phase power supply. Each phase voltage of the secondary side winding is divided into n independent low voltages. Taking the first phase voltage as an example, each independent low voltage is connected to the phase The corresponding power unit modules are connected, and the output ends of the power unit modules 11 to 1n are cascaded in sequence, that is, the output negative port 11N of the power unit module 11 is connected to the output positive port 12P of the power unit module 12, and the output negative port 12N of the power unit module 12 It is connected to the positive output port 13P of the power unit module 13, and so on; similarly, the second and third phase voltages are connected to the power unit module in the same way as the first phase. The output ports after the cascaded power modules of each phase are 11P and 1nN, 21P and 2nN, 31 and 3n;

b. The output terminals 11P, 21P, and 31P are connected to point P, and connected to the positive end of the load or traction network after being filtered by the LC filter circuit. The output terminals 1nN, 2nN, and 3nN are jointly connected to point N, and connected to the load or traction network. The negative terminal is connected to realize the parallel connection of three single-phase AC output voltages;

The power unit module is a single-phase-single-phase PWM converter.

The cascaded-parallel hybrid converter of the utility model can make low-voltage devices applied to high-voltage occasions, realize the output of the converter at a higher voltage level, and the parallel connection of the converters can increase the level of the output current to meet the high-current output of the converter system requirements. The output terminal can be connected to the load, so this device can be regarded as a three-phase-single-phase converter; this device can also be used in the same-phase power supply system of electrified railways, and the output terminal can supply power for the traction network, providing energy for the three-phase power supply A Phases 1, B, and C can jointly share the power required by the load or traction network, and the energy can flow in both directions.

Compared with the prior art, the beneficial effect of the utility model is that: it can be regarded as a three-phase-single-phase converter to provide energy for different loads; for electrified railways, since the output rated voltage is 27.5kv, it cannot pass Continue to increase the output voltage level to meet the higher capacity demand of the load, so the utility model improves its topology structure on the basis of cascading on the inverter side, adds a parallel structure, and combines the advantages of cascading converters to improve the voltage level with parallel Combining the advantages of increasing the current level, it can achieve high power output and meet different design requirements.

Description of drawings

Fig. 1 is the schematic circuit diagram of the utility model embodiment;

Figure 2 is a single-phase-single-phase PWM converter based on a two-level H-bridge structure;

Figure 3 is a single-phase-single-phase PWM converter based on a three-level diode clamp structure.

Detailed ways

The utility model is described in further detail below in conjunction with accompanying drawing and specific embodiment.

Fig. 1 is the main circuit diagram of the cascade-parallel hybrid converter of the present invention, the energy is provided by the three-phase power supply, the power supply is divided into three phases through the split transformer, the primary side winding of the split transformer is connected to the three-phase power supply, and the secondary side winding Each phase voltage is divided into n independent low voltages, as shown in Figure 1 U _N1 , U _N2 , U _N3 , taking the first phase voltage as an example, each independent low voltage corresponds to the corresponding The power unit modules are connected, and the output ends of the power unit modules 11 to 1n are cascaded in sequence, that is, the output negative port 11N of the power unit 11 is connected to the output positive port 12P of the power unit 12, and the output negative port 12N of the power unit 12 is connected to the output port 12N of the power unit 13. The output positive port is connected to 13P, and so on. Similarly, the connection method of the voltage of the second and third phases and the power unit module is the same as that of the first phase. The output ports after the cascaded power modules of each phase are 11P and 1nN, 21P and 2nN, 31 and 3n respectively. The output terminals 11P, 21P, and 31P are connected to point P, and connected to the positive end of the load or traction network after being filtered by the LC filter circuit, and the output terminals 1nN, 2nN, and 3nN are connected to point N, and connected to the negative end of the load or traction network. To realize the parallel connection of three single-phase AC output voltages. The power unit module is a single-phase-single-phase PWM converter, and the converter may have a two-level structure, as shown in FIG. 2 , or a multi-level structure, such as a three-level diode clamp structure in FIG. 3 .

The utility model proposes a cascade-parallel hybrid converter. The cascading of converters can make low-voltage devices be applied to high-voltage occasions, and realize the output of the converter at a higher voltage level, and the parallel connection of the converters can increase the level of output current to meet Requirements for large current output of the converter system. The output terminal can be connected to the load, so this device can be regarded as a three-phase-single-phase converter; this device can also be used in the same-phase power supply system of electrified railways, and the output terminal can supply power for the traction network, providing energy for the three-phase power supply A Phases 1, B, and C can jointly share the power required by the load or traction network, and the energy can flow in both directions.

Claims (2)

1. A cascade-parallel hybrid converter device, characterized in that the energy is provided by a three-phase power supply, the power supply is divided into three phases by a transformer, and each phase voltage of the secondary winding is cut into several independent low These independent voltages pass through single-phase-single-phase converters respectively, and are cascaded to form single-phase AC output voltages; and the cascaded outputs of each phase are connected in parallel and then connected to the load through an LC filter circuit to form a three-phase-single-phase converter , the specific connection method is: a. The primary side winding of the split transformer is connected to the three-phase power supply. Each phase voltage of the secondary side winding is divided into n independent low voltages. Taking the first phase voltage as an example, each independent low voltage is connected to the phase The corresponding power unit modules are connected, and the output ends of the power unit modules 11 to 1n are cascaded in sequence, that is, the output negative port 11N of the power unit module 11 is connected to the output positive port 12P of the power unit module 12, and the output negative port 12N of the power unit module 12 It is connected to the positive output port 13P of the power unit module 13, and so on; similarly, the second and third phase voltages are connected to the power unit module in the same way as the first phase. The output ports after the cascaded power modules of each phase are 11P and 1nN, 21P and 2nN, 31 and 3n; b. The output terminals 11P, 21P, and 31P are connected to point P, and connected to the positive end of the load or traction network after being filtered by the LC filter circuit. The output terminals 1nN, 2nN, and 3nN are jointly connected to point N, and connected to the load or traction network. The negative terminal is connected to realize the parallel connection of three single-phase AC output voltages; The power unit module is a single-phase-single-phase PWM converter. 2. The cascade-parallel hybrid converter device according to claim 1, characterized in that, the converter can be of a two-level structure or a multi-level structure.