RU2475911C1 - Low-inductance three-pole busbar assembly - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: busbar assembly contains the central bus 1 and two outer buses 2 and 3, fixed with non-conductive tension pieces. Buses 2 and 3 are separated from the central bus 1 with dielectric gaskets 4 all along the busbar assembly extension. The current conductive buses 1, 2 and 3 are positioned parallel to each other and together with the gaskets 4 are fixed with the help of several non-conductive tension pieces installed along the busbar assembly. The non-conductive tension pieces are made of a polymer material and designed in the form of adjustable clamps 5 tensioned with the help of bolts 6 and nuts 7. Each of buses 2 and 3 includes an extended part 8 of rectangular cross-section while bus 1 contains two extended parts 9 and 10 of rectangular cross-section that are separated with an air gap. Electrical interconnection of parts 9 and 10 is performed at the end of the busbar assembly located next to the capacitor banks 13, 14. All the current conductive buses are equipped with tap leads for connection of the converter circuit power elements: capacitor tanks and switching elements (thyristors or IGBT transistors). The tap leads 11 of the central bus 1 and the tap leads 12 of the outer buses 2 and 3 are positioned within mutually perpendicular planes.

EFFECT: enhancement of the busbar assembly output capacity without inductance increase.

2 dwg

Description

Technical field

The invention relates to the electric power industry and can be used in the installation of power current-carrying buses of powerful static voltage converters.

State of the art

Long busbar assemblies of small inductance are used in powerful static converters for connecting capacitor banks with inverter switching elements remote from them.

Known as a prototype is a three-pole low-inductance busbar assembly designed for high-power static voltage converters and containing conductive busbars in parallel fixed by non-conductive couplers: a central bus and two outer buses separated by dielectric spacers throughout the busbar assembly, each bus having taps for connecting capacitor banks and switching elements of the converter [PCT application WO 2002/080324]. Due to the close parallel arrangement of the current-carrying tires and the separation of the outermost tires from the central bus with dielectric spacers throughout the busbar assembly, the current-carrying tires of the prototype have low inductance.

A disadvantage of the known device is the poor cooling conditions of the central bus, which is covered by dielectric gaskets, which carries the greatest current load.

Disclosure of invention

The technical result of the invention is to increase the load capacity of the tire assembly without increasing its inductance.

The subject of the invention is a three-pole low-inductance busbar assembly, comprising a central bus and two outer buses parallel to the central bus, separated from the central bus by dielectric spacers throughout the busbar assembly, each bus having taps for connecting capacitor banks and switching elements of the voltage converter, and the central the bus is made of two parallel parts separated by an air gap and having an electrical connection to tse busbar located in capacitor banks.

This set of features allows you to get the above technical result.

Brief Description of the Drawings

Figure 1 shows the tire assembly in cross section. Figure 2 illustrates the use of busbar assembly in a powerful static Converter.

The implementation of the invention

The busbar assembly shown in FIG. 1 comprises a central bus 1 and two outermost busbars 2 and 3 parallel to the non-conductive couplers. Tires 2 and 3 are separated from the central bus 1 by dielectric spacers 4 throughout the bus assembly. Tires 1, 2 and 3 are parallel to each other and together with gaskets 4 are fixed using several non-conductive couplers installed along the tire assembly.

Non-conductive screeds are made of polymeric material in the form of clamps 5, tightened with bolts 6 and nuts 7. Each of tires 2 and 3 includes an extended part 8 of rectangular cross-section, and tire 1 - two extended parts 9 and 10 of rectangular cross-section, which are separated by an air gap . To reduce the inductance, the electrical connection of parts 9 and 10 is performed only at one end of the busbar assembly, near the capacitor banks.

Conducting buses 1, 2 and 3 are equipped with taps for connecting power elements of the converter circuit: capacitor banks and switching elements (thyristors or transistors IGBT). The bends 11 of the central tire 1 and the bends 12 of the outermost tires 2 and 3 shown in FIG. 1 are located in mutually perpendicular planes.

Figure 2 illustrates the use of a busbar assembly in a powerful power inverter that is part of a voltage converter. The inverter, the circuit of which is shown in figure 2, includes two series-connected capacitor banks 13 and 14, the midpoint 15 of which is connected to a neutral bus 1 having zero potential. Point 15 may be grounded. A bus 2 is connected to the second terminal of the battery 13 being charged to a positive potential, and a bus 3 is connected to the second terminal of the battery 14 being charged to negative potential. The battery charging circuits 13 and 14 are not shown in FIG. 2.

The inverter using the keys 16 installed in each phase, generates an alternating current of the required frequency. The formation is carried out by the method of pulse width modulation (PWM) by switching the phase between the three levels of constant voltage coming from the batteries 13 and 14. In this case, the operating switching frequency of the keys 16 is usually close to 3.0 kHz. Given the large currents flowing along the buses 1, 2 and 3, stringent inductance requirements are imposed on the busbar assembly to avoid large overvoltages when switching keys 16. Both in the prototype and in the proposed design, low inductance is ensured due to small gaps and insulation between any of the outermost tires and the central tire throughout the tire assembly.

Moreover, in the design of the prototype, a single central tire throughout the busbar assembly is enclosed between the dielectric plates separating it from the outermost tires, and therefore most of its surface is not cooled by air.

The execution of the Central bus of two parallel parts separated by an air gap and having an electrical connection between the parallel parts only at the end of the bus assembly located at the capacitor banks, significantly improves the thermal regime of the Central bus while maintaining its low inductance character. Since the central stud is most loaded (its average current is twice the average current of each extreme bus), this allows to increase the load capacity of the proposed tire assembly as a whole.

Claims (1)

A three-pole busbar assembly containing a central bus and two end buses parallel to the central bus and insulated by dielectric spacers throughout the busbar assembly, while each bus is equipped with taps for connecting capacitor banks and switching elements of the voltage converter, and the central bus is made of two parallel parts separated by an air gap and having an electrical connection at the end of the busbar assembly located at the capacitor batteries.

Images