CN201708701U - Power assembly of back-to-back type three-level static frequency converter - Google Patents

Abstract

The utility model provides a power assembly of a back-to-back three-level static frequency converter, which is characterized in that it includes two connected power assembly water-cooled radiators, and an IGBT module and One diode module, at the same time, two IGBT modules are installed on the front and back sides of the water-cooled radiator of another power component, and the four IGBT modules are connected in series between the DC positive pole and the DC negative pole to form two bridge arms. There is an input/output terminal between the two IGBT modules, a diode module is connected between the midpoint of each bridge arm and the 0 point, and a absorption capacitor is connected between the DC positive pole and the DC negative pole and the 0 point. . The utility model has the advantages of compact structure, high-standard interchangeability, water-cooled radiator with excellent heat dissipation effect, enhanced heat dissipation effect, and independent heat dissipation system.

Description

A power component of a back-to-back three-level static frequency converter

technical field

The utility model relates to a power component of a three-level static frequency converter.

Background technique

Static frequency converter is a starting device with reliable operation and excellent performance. It has been proposed for decades, and it has entered the stage of general application in foreign countries, operating in gas turbine units, pumped storage power plants, blast furnace blowers, etc. A set of starting device can start several large-scale units in sequence, saving equipment investment. On the other hand, the cost of the static variable frequency starting device is high, the system is complicated, and requires a high level of technology and maintenance. However, with the development of power electronics technology, these problems have been increasingly solved.

Compared with the ordinary two-level PWM inverter, the three-level static inverter has increased the number of output line voltage levels from 2 to 3, and the amplitude of each level is relatively low, and the entire DC bus voltage is reduced to Half of the DC bus voltage, the output dv/dt also decreases accordingly; under the premise of the same switching frequency, the use of a three-level structure can also greatly improve the quality of the output waveform. If the input also adopts a symmetrical three-level PWM rectification structure, the input power factor can be adjusted, the input harmonics are low, and it can run in four quadrants. The system has high dynamic performance.

Nowadays, the application of frequency converters is increasing day by day, and the requirements for the reliability of frequency converters are getting higher and higher. There are a number of reliability indicators that affect the frequency converter, among which heat dissipation and ventilation are a crucial link in the design process. Generally speaking, due to the high power of the equipment, a large amount of heat is still generated during normal operation. In order to ensure the normal operation of the equipment, it is necessary to dissipate a large amount of heat, optimize the heat dissipation and ventilation scheme, and realize the efficient heat dissipation of the equipment to improve the reliability of the equipment.

When the frequency converter is working normally, the power components are the main source of heat, and the heat dissipation of the power devices as the electronic switches of the main circuit and the heat dissipation design of the power components become the most important accordingly. The temperature rise caused by the dissipated power of the power device needs to be reduced by the radiator. The radiator increases the heat conduction and radiation area of the power device, expands the heat flow, and buffers the transition process of heat conduction. The heat is transferred directly or by means of a heat transfer medium to the cooling system. medium. At present, the cooling methods commonly used in high-voltage inverters are forced air cooling, circulating water cooling, and heat pipe radiator cooling. Due to the advantages of small size, high efficiency, and no pollution, the water cooling method has the advantages of small size, high efficiency, and no pollution. The temperature difference between the surface of the radiator and the fluid is relatively small. On the one hand, it can increase the power, on the other hand, it can reduce the temperature of the chip and increase its life. Therefore, using water cooling to cool the inverter is an important measure to improve the reliability of the equipment and reduce the size of the equipment.

When designing the power components of the three-level inverter, while satisfying the heat dissipation design, the convenience of loading and unloading, inspection and maintenance of the equipment should be fully considered. But so far there is no power component that can meet the requirements.

Contents of the invention

The purpose of the utility model is to provide a power assembly suitable for a back-to-back three-level static frequency converter.

In order to achieve the above purpose, the technical solution of the utility model is to provide a power assembly of a back-to-back three-level static frequency converter, which is characterized in that it includes two connected power assembly water-cooled radiators, and the power assembly water-cooled radiator passes through The support column of the water-cooled radiator is set on the support plate of the power module. The two ends of the water-cooled radiator of each power module are directly connected to the water inlet pipe and the return pipe of the main circulating water pipe through the connector of the water-cooled radiator. One IGBT module and one diode module are installed on both sides of the device. At the same time, two IGBT modules are installed on both sides of the water-cooled radiator of another power component. The four IGBT modules are connected in series between the DC positive pole and the DC negative pole to form two A bridge arm, an input/output terminal is drawn between the two IGBT modules in the middle, a diode module is respectively connected between the midpoint of each bridge arm and the 0 point, and the DC positive pole and the DC negative pole are connected to 0 A snubber capacitor is connected across the points respectively.

The utility model has the advantages of:

1. Compact structure, "back to back" installation. The power components are installed on both sides of the water cooling radiator of the power components, that is, "back to back" installation. This compact structure makes the power components meet the heat dissipation requirements and achieve the heat dissipation effect, which is better than using two single-sided The solution of installing the radiator saves half the space. Therefore, the compact structure reduces the size of the power components, which can greatly reduce the size of the whole machine.

2. Unified power module structure. The rectification part of the three-level inverter and the inverter part of the three-level inverter can be designed as two identical parts, and each phase in the rectification part of the three-level inverter and the inverter part of the three-level inverter can be designed as A total of six identical power components. Therefore, the design of the power module uniformly installs the power device on both sides of the water-cooled radiator of the power module, and then fixes it on the support plate of the power module through the insulated water-cooled radiator support column to form a whole power module, which can make the power module integrated It is convenient for assembly, inspection and maintenance, so that the rectification part of the three-level inverter and the inverter part of the three-level inverter use the same power components.

3. High standard interchangeability. The circuit of the power component is simple, the structure is clear, and the technology is mature and reliable. In addition, the modular structure is adopted, and the power components of the rectification part of the three-level inverter and the inverter part of the three-level inverter can be interchanged without any modification due to their unified standard structure. At the same time, the assembly And maintenance is also very convenient.

4. Water-cooled radiator with excellent heat dissipation effect. The power component uses the power component water-cooling radiator to cool the power device, so that the IGBT module and diode module installed on the surface of the power component water-cooling radiator can be fully cooled and cooled, and the temperature rise of the power device is strictly controlled not to exceed the rated value to meet the requirements of the device. Normal operation within the rated temperature range can effectively improve equipment reliability.

5. Enhanced cooling effect. The inside of the power module water-cooling radiator is formed by three S-shaped water channels. Springs with the same length as the water channels are respectively added to the three water channels inside the power component water-cooling radiator, which can effectively increase the flow resistance of the circulating water passing through the water channels and strengthen the water channels. The turbulence effect of the water flow inside, thereby increasing the heat transfer coefficient of the water-cooled radiator of the power component, and enhancing the heat dissipation effect of the water-cooled radiator of the power component.

6. Independent cooling system. Each power component has its own independently used power component water cooling radiator, so that it can provide its own suitable heat dissipation power. At the same time, in order to achieve better heat dissipation effect for the IGBT module and diode module on the power component water cooling Effect and heat dissipation requirements, each power component is connected with two identical and relatively independent power component water-cooling radiators for installation and heat dissipation, and the two ends of each power component water-cooling radiator are directly connected to the The water inlet and return pipes of the main circulating water pipe enhance the heat dissipation effect of the water-cooled radiator of each power component.

Description of drawings

Figure 1 is a schematic diagram of a dual SVPWM three-level inverter with bidirectional energy flow;

Figure 2 is a schematic diagram of the power components of the back-to-back three-level static inverter;

Fig. 3 is a perspective view of the power component structure of the back-to-back three-level static frequency converter;

Fig. 4 is a perspective view of the water cooling radiator of the power assembly.

Detailed ways

The utility model is described in detail below in conjunction with embodiment.

Example

As shown in Figure 1, it is a schematic diagram of a dual SVPWM three-level inverter with bidirectional energy flow. This method allows the feedback of all motor energy, reduces input harmonics and improves power factor. Diode-clamped three-level voltage source type high-high frequency converter considers the three-level voltage source type high-high frequency converter has high operating power factor, fast response speed, small number of components, reduced cabinet size, and single-machine operation reliability high feature. The three-level voltage source inverter directly adopts the voltage source inverter of the high-voltage IGBT power device, which adopts the traditional AC-DC-AC inverter structure, and is a dual SVPWM three-level inverter with bidirectional energy flow. . According to its schematic diagram, the rectification part 1 of the three-level inverter and the inverter part 2 of the three-level inverter can be designed as two identical parts, and the rectification part 1 of the three-level inverter and the inverter part of the three-level inverter Each phase in 2 can be designed as a total of six identical power components.

As shown in Figure 2, it is a schematic diagram of the utility model. Since the three-level inverter rectifier part 1 and the three-level inverter inverter part 2 are divided into six identical power components, the three-level inverter rectifier The input terminal of the power component in part 1 and the output terminal of the power component in part 2 of the three-level inverter inverter are the same connection points in the general power module. Each power component has input\output, 0 point, DC positive pole and DC negative four connection points. In the rectification part 1 of the three-level frequency converter, one phase of the three-phase alternating current is introduced from the input terminal, and the bridge arms of the two IGBT modules 3 are connected in series respectively. The diode module 4 is clamped, and an absorption capacitor 5 is installed between the DC positive pole, the DC negative pole and 0, and it is rectified into direct current, which is respectively the DC positive pole and the DC negative pole, and enters the inverter part 2 of the three-level frequency converter; similarly, In the inverter part 2 of the three-level inverter, the rectified DC positive pole and DC negative pole enter the power component, and respectively pass through the bridge arms of two IGBT modules 3 connected in series. The diode module 4 is used for clamping, and the absorption capacitor 5 is installed between the DC positive pole and the DC negative pole and 0 point, and the output terminal is inverted into one phase of the three-phase AC output.

As shown in FIG. 3 , it is a three-dimensional view of the structure of the utility model. In order to achieve a better heat dissipation effect, two identical power module water-cooled radiators 6 are connected for installation and heat dissipation. In the power assembly, one IGBT module 3 and one diode module 4 are installed on both sides of the power assembly water-cooling radiator 6, and at the same time, two IGBT modules 3 are installed on the front and back of the connected power assembly water-cooling radiator 6. On both sides, the absorption capacitor 5 is respectively installed between the DC positive pole, the DC negative pole and the 0 point, and the connection points between the components inside the power component and the power components are electrically connected by copper bars; the water-cooled radiator 6 in each power component The two ends of the water-cooling radiator are respectively directly connected to the water inlet pipe and the return pipe of the main circulating water pipe through the water-cooling radiator connector 7; at the same time, the insulated water-cooling radiator support column 8 is fixed on the power assembly support plate 9 to form a power assembly overall.

As shown in Figure 4, it is a three-dimensional view of the water-cooled radiator of the power assembly of the present invention. The water-cooled radiator 6 of the power assembly cools the power device and is used to fully cool the IGBT module 3 and the diode module 4 installed on its surface, strictly Controlling the temperature rise of the power device does not exceed the rated value, so that the device can work normally within the rated temperature range, can effectively improve the reliability of the device. In addition, in the S-shaped water channel inside the water-cooled radiator 6 of the power assembly, springs with the same length as the water channel are respectively added, which can effectively increase the flow resistance of the circulating water passing through the water channel, and enhance the turbulence effect of the water flow in the water channel, thereby The heat transfer coefficient of the water-cooled radiator 6 of the power component is increased, and the heat dissipation effect of the water-cooled radiator 6 of the power component is enhanced. At the same time, each power component has its own independently used power component water-cooling radiator 6, so that it can provide its own suitable heat dissipation power, and each power component uses two identical and relatively independent power component water-cooling radiators 6 to be connected for installation For heat dissipation, the two ends of the water-cooled radiator 6 of each power module are directly connected to the water inlet pipe and the return pipe of the main circulating water pipe through the water-cooled radiator connector 7, so as to enhance the heat dissipation effect of the water-cooled radiator 6 of each power module.

Claims (1)

1. A power assembly of a back-to-back three-level static frequency converter, characterized in that it comprises two connected power assembly water-cooled radiators (6), and the power assembly water-cooled radiator (6) passes through the water-cooled radiator support column ( 8) Installed on the power module support plate (9), the two ends of each power module water-cooled radiator (6) are directly connected to the water inlet pipe and return pipe of the main circulating water pipe through the water-cooled radiator connector (7). Install an IGBT module (3) and a diode module (4) on both sides of a power component water-cooling radiator (6), and at the same time, install two IGBTs on both sides of the other power component water-cooling radiator (6) module (3), four IGBT modules (3) are serially connected in series between the DC positive pole and the DC negative pole to form two bridge arms, and an input/output terminal is drawn between the two IGBT modules (3) in the middle. A diode module (4) is respectively bridged between the midpoint of each bridge arm and the zero point, and a absorbing capacitor (5) is respectively bridged between the DC positive pole and the DC negative pole and the zero point.

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