A kind of stack bus bar for T-shaped three-level current transformer
Technical field
The utility model relates to three-level current transformer technical field, is specifically related to a kind of stack bus bar for T-shaped three-level current transformer.
Background technology
In high-power photovoltaic synchronization inverter, generally use power electronics semiconductor switch device insulated gate bipolar transistor (IGBT) as switching device, in switching device switch motion process, need the support of bus capacitor, circulation loop is provided.The performance of modern power electronic switching device is become better and better, and switching speed is more and more faster, also more and more higher to the requirement of circulation loop parasitic parameter.Fixing and the mounting means of bus capacitor generally adopts the fixing mode of busbar, the mode of wherein applying stack bus bar fixed capacity because of its parasitic parameter less, applied widely.
Three-level current transformer is better because exporting the quality of power supply in its course of work, and the advantage that system electrical property is good, stability is high becomes the main flow of product gradually.In photovoltaic combining inverter, three-level current transformer is mainly used in middle low power type inverter.In high-power inverter, three level are not also widely used.
Stack bus bar based on three-level current transformer is different from the stack bus bar of two level current transformers, at aspects such as terminal setting, the design of lamination current potential, circulation loop designs, need to have special requirement.At present, also very few for the application of dc-link capacitance stack bus bar in T-shaped three-level current transformer, need to further further investigate.
Summary of the invention
The shortcoming existing in order to overcome above-mentioned prior art, the purpose of this utility model is to provide a kind of stack bus bar for T-shaped three-level current transformer, the utility model is for installing and the fixing dc-link capacitance of current transformer, in conjunction with circuit loop in current transformer, the mounting arrangement of bus capacitor is designed, effectively reduce the stray inductance in loop, thereby reduced the crest voltage of switching device; Simultaneously the installation site of each parallel connection direct bus capacitor symmetry of arranging in stack bus bar, makes the ripple current of dc-link capacitance in each parallel branch more even, is of value to the life-span that extends bus capacitor.
In order to achieve the above object, the utility model adopts following technical scheme:
A kind of stack bus bar for T-shaped three-level current transformer, described stack bus bar comprises seven layers that overlap together, be followed successively by: ground floor insulating barrier L1, the positive busbar L2 of second layer electric capacity, the three-layer insulated layer of L3, the 4th layer capacitance zero busbar L4, layer 5 insulating barrier L5, the negative busbar L6 of layer 6 electric capacity and layer 7 insulating barrier L7, the positive busbar L2 of described second layer electric capacity has positive input terminal and the three-phase positive output end of this stack bus bar, described the 4th layer capacitance zero busbar L4 has a reset terminal and N the zero-output terminal of this stack bus bar, N is more than or equal to 3 positive integer, 3 zero-output terminals wherein form three zero-output terminals, the negative busbar L6 of described layer 6 electric capacity has negative input end and the three-phase negative output terminal of this stack bus bar, the upper and lower distribution straggly of positive input terminal, reset terminal and negative input end of the positive busbar L2 of described second layer electric capacity, the 4th layer capacitance zero busbar L4, the negative busbar L6 of layer 6 electric capacity, the three-phase positive output end of the positive busbar L2 of described second layer electric capacity, the 4th layer capacitance zero busbar L4, the negative busbar L6 of layer 6 electric capacity, three zero-output terminals and all upper and lower distributions straggly of three-phase negative output terminal, described positive input terminal, reset terminal and negative input end are positive input terminal, reset terminal and the negative input end of current transformer, described three-phase positive output end, three zero-output terminals and three-phase negative output terminal respectively with the input of each phase of three phase power module of current transformer corresponding being connected respectively.
Described seven layers of overlapping together synthesize after an integral body or seven layer material laminations by hot pressing, pass through screw in compression.
Each of described stack bus bar layer is rectangle, and a positive input terminal of the positive busbar L2 of second layer electric capacity is positioned at the position, middle of the shorter side of rectangle, and three positive output ends are positioned at the long side of stack bus bar, and are uniformly distributed; A reset terminal of described the 4th layer capacitance zero busbar L4 is positioned at the shorter side of rectangle by rear position, and three zero-output terminals are positioned at the long side of stack bus bar, keep right and arrange and be uniformly distributed respectively than three positive output ends of the positive busbar L2 of second layer electric capacity; A negative input end of the negative busbar L6 of described layer 6 electric capacity is positioned at the shorter forward position of side of rectangle, and three-phase negative output terminal is positioned at the long side of stack bus bar, keeps left and arranges and be uniformly distributed respectively than three positive output ends of the positive busbar L2 of second layer electric capacity.
The positive input terminal of described stack bus bar, reset terminal and negative input end are evenly distributed in the shorter side of rectangle stack bus bar, the three-phase positive output end of described stack bus bar, three zero-output terminals and three-phase negative output terminal are evenly distributed in the long side of rectangle stack bus bar, and three outputs of every phase are arranged in order according to identical order.
The position, hole that is used for installing bus capacitor on described stack bus bar is divided into three parts, be respectively first area A, second area B and the 3rd region C, in each region, have the mounting hole site by two groups of capacitances in series, and every group of electric capacity is comprised of a plurality of Capacitance parallel connections.
The direction of described mounting hole site is parallel with the direction of stack bus bar output.
The material of the ground floor insulating barrier L1 of described stack bus bar, the three-layer insulated layer of L3, layer 5 insulating barrier L5 and layer 7 insulating barrier L7 is insulating paper.
Compared to the prior art, tool has the following advantages the utility model:
1, parallel with the direction of stack bus bar output owing to fixing position, the hole direction of two terminals of each bus capacitor, bus capacitor closed loop flow path is short, so stack bus bar for T-shaped three-level current transformer that the utility model provides, its loop inductance is less, effectively reduce the overvoltage of switch collector electrode, improved the reliability of electronic power switch device work.
2, the stack bus bar spatial arrangement for T-shaped three-level current transformer that the utility model provides is symmetrical, and the current ripples that makes to be fixed on each bus capacitor on stack bus bar is more even, is of value to the life-span that extends bus capacitor.
3, the laminated bus bar structure for T-shaped three-level current transformer that the utility model provides is compact, and cost is lower.
Accompanying drawing explanation
Fig. 1 is the stack bus bar hierarchical diagram of T-shaped three-level current transformer.
Fig. 2 is the basic circuit schematic diagram of T-shaped three-level current transformer single module.
Fig. 3 is the positive busbar of second layer electric capacity, the 4th layer capacitance zero busbar, the negative busbar schematic diagram of layer 6 electric capacity.
Fig. 4 is the negative busbar detailed maps of layer 6 electric capacity.
Fig. 5 is capacitor discharge schematic diagram between the positive busbar of second layer electric capacity and the 4th layer capacitance zero busbar.
Fig. 6 is current diagram in capacitor discharge process busbar between the positive busbar of second layer electric capacity and the 4th layer capacitance zero busbar.
Fig. 7 is capacitor charging schematic diagram between the negative busbar of layer 6 electric capacity and the 4th layer capacitance zero busbar.
Fig. 8 is current diagram in capacitor charging process busbar between the negative busbar of layer 6 electric capacity and the 4th layer capacitance zero busbar.
Fig. 9 is the space layout figure that stack bus bar is installed electric capacity.
Embodiment
Below in conjunction with the drawings and the specific embodiments, the utility model is described in further detail.
As shown in Figure 1, a kind of stack bus bar for T-shaped three-level current transformer of the utility model, comprise seven layers that overlap together, be followed successively by: ground floor insulating barrier L1, the positive busbar L2 of second layer electric capacity, the three-layer insulated layer of L3, the 4th layer capacitance zero busbar L4, layer 5 insulating barrier L5, the negative busbar L6 of layer 6 electric capacity and layer 7 insulating barrier L7, the positive busbar L2 of described second layer electric capacity has positive input terminal and the three-phase positive output end of this stack bus bar, described the 4th layer capacitance zero busbar L4 has a reset terminal and N the zero-output terminal of this stack bus bar, N is more than or equal to 3 positive integer, 3 zero-output terminals wherein form three zero-output terminals of this stack bus bar, the negative busbar L6 of described layer 6 electric capacity has negative input end and the three-phase negative output terminal of this stack bus bar, seven layers of overlapping together of the present embodiment synthesize an integral body by hot pressing.
As the preferred embodiment of the present invention, each of described stack bus bar layer is rectangle, a positive input terminal of the positive busbar L2 of second layer electric capacity is positioned at the position, middle of the shorter side of rectangle, and three positive output ends are positioned at the long side of stack bus bar, and are uniformly distributed; A reset terminal of described the 4th layer capacitance zero busbar L4 is positioned at the shorter side of rectangle by rear position, and three zero-output terminals are positioned at the long side of stack bus bar, keep right and arrange and be uniformly distributed respectively than three positive output ends of the positive busbar L2 of second layer electric capacity; A negative input end of the negative busbar L6 of described layer 6 electric capacity is positioned at the shorter forward position of side of rectangle, and three-phase negative output terminal is positioned at the long side of stack bus bar, keeps left and arranges and be uniformly distributed respectively than three positive output ends of the positive busbar L2 of second layer electric capacity.
As the further preferred implementation of the present invention, the positive input terminal of described stack bus bar, reset terminal and negative input end are evenly distributed in the shorter side of rectangle stack bus bar, the three-phase positive output end of described stack bus bar, three zero-output terminals and three-phase negative output terminal are evenly distributed in the long side of rectangle stack bus bar, and three outputs of every phase are arranged in order according to identical order.
As the preferred embodiment of the present invention, the position, hole that is used for installing bus capacitor on described stack bus bar is divided into three parts, be respectively first area A, second area B and the 3rd region C, in each region, have the mounting hole site by two groups of capacitances in series, and every group of electric capacity is comprised of a plurality of Capacitance parallel connections.First area A, second area B and the 3rd region C be the three-phase of corresponding stack bus bar three-phase positive output end, three zero-output terminals and three-phase negative output terminal respectively.
As the preferred embodiment of the present invention, position, the hole direction of fixing two terminals of each bus capacitor is parallel with the direction of stack bus bar output.
As the preferred embodiment of the present invention, the material of the ground floor insulating barrier L1 of described stack bus bar, the three-layer insulated layer of L3, layer 5 insulating barrier L5 and layer 7 insulating barrier L7 is insulating paper.
As shown in Figure 2, be the basic circuit schematic diagram of T-shaped three-level current transformer single module, this circuit is comprised of stack bus bar, electric capacity and T-shaped three-level current transformer module.Wherein P1, Z1, N1 are respectively positive input terminal, reset terminal, the negative input ends of stack bus bar.PC, ZC, NC are respectively that the zero busbar L4 of tie point position, the 4th layer capacitance that the positive busbar L2 of second layer electric capacity connects bus capacitor connects the tie point position of bus capacitor and the tie point position that the negative busbar L6 of layer 6 electric capacity connects bus capacitor.P2X, Z2X, N2X represent respectively positive output end, zero-output terminal, the negative output terminal of stack bus bar.Wherein X can be expressed as A, B, C, and P2A represents the output corresponding to A phase, and P2B represents the output corresponding to B phase, and P2C represents the output corresponding to C phase, and AC is the output of single-phase power module.P1, PC, the P2X positive busbar L2 of the electric capacity layer that coexists in Fig. 2; Z1, ZC, the Z2X electric capacity zero busbar L4 layer that coexists; N1, NC, the N2X negative busbar L6 layer of electric capacity that coexists.Wherein P1, Z1, N1 are the direct-flow input end of T-shaped three-level current transformer single module, and P2X, Z2X, N2X are the output of bus stack bus bar, and are connected with the input of each phase power model.
As shown in Figure 3, be the positive busbar of second layer electric capacity in stack bus bar, the 4th layer capacitance zero busbar, the negative busbar schematic diagram of layer 6 electric capacity, the position that wherein each label is corresponding is corresponding with each label in Fig. 2.
As shown in Figure 4, be the negative busbar detailed maps of layer 6 electric capacity of stack bus bar, the position that wherein each label is corresponding is corresponding with each label in Fig. 2.
Current path schematic diagram and the corresponding current trend schematic diagram on busbar when discharging for the bus capacitor between the positive busbar of second layer electric capacity and the 4th layer capacitance zero busbar as shown in Figure 5 and Figure 6.
Current path schematic diagram and the corresponding current trend schematic diagram on busbar when charging for the bus capacitor between the negative busbar of layer 6 electric capacity and the 4th layer capacitance zero busbar as shown in Figure 7 and Figure 8.
As shown in Figure 9, for the schematic diagram of N bus capacitor is installed on stack bus bar, the mode that all electric capacity adopts space uniform to arrange, electric capacity current sharing is good.The upper and lower distribution straggly of positive input terminal, reset terminal and negative input end of the positive busbar L2 of described second layer electric capacity, the 4th layer capacitance zero busbar L4, the negative busbar L6 of layer 6 electric capacity; The three-phase positive output end of the positive busbar L2 of described second layer electric capacity, the 4th layer capacitance zero busbar L4, the negative busbar L6 of layer 6 electric capacity, three zero-output terminals and all upper and lower distributions straggly of three-phase negative output terminal; Often be in parallel position and the every phase output terminal of busbar of electric capacity of described stack bus bar is symmetrical in layout, can make like this electric current on each shunt capacitance reach balanced, plays current balance function.Described positive input terminal, reset terminal and negative input end are positive input terminal, reset terminal and the negative input end of current transformer, described three-phase positive output end, three zero-output terminals and three-phase negative output terminal respectively with the input of each phase of three phase power module of current transformer corresponding being connected respectively.