Brake resistor with single flat sheet and drive system with brake resistor
By adopting a single-flat design and a curved edge structure in the brake resistor, combined with an inverter-powered drive system, the problem of large space occupation and high cost of brake resistors in the prior art is solved, and compact and low noise is achieved and high frequency effects.
Patent Information
- Application Number
- CN202380038792.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-05-12
- Filing Date
- 2023-04-20
- Publication Date
- 2024-12-17
AI Technical Summary
The existing brake resistor design has problems such as large space occupation and high cost, and is also very noisy when the converter is powered.
Using a single flat sheet design, by setting alternating first and second transverse slots in the longitudinal direction, forming a meandering material direction, using rectangular flat steel plates and curved edges to improve rigidity, reduce noise, and in the drive system Use an inverter-powered motor and brake chopper to control the voltage.
A compact braking resistor design is realized, reducing cost and noise, improving mechanical resonance frequency, and reducing structural noise and acoustic radiation.
Smart Images
Figure CN119156678A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a braking resistor with a single flat plate and a driving system with the braking resistor. Background Art
[0002] It is known to use braking resistors for converting generator energy into heat energy.
[0003] As the closest prior art, a resistance element is known from JP H08-78 201A.
[0004] A resistor arrangement is known from DE 10 2010 055 475 A1.
[0005] From KR 10 2009 123 072 A a braking resistor for a crane is known.
[0006] From DE 10 2016 004 062 A1 a drive is known which has an electric motor which is supplied by a converter.
[0007] A resistor element is known from JP 000S51161542U.
[0008] Also known from FR 1 479 622 A is a resistor element.
[0009] A resistor is known from US Pat. No. 4,588,976 A.
[0010] A resistance grid is known from US Pat. No. 2,665,358 A.
[0011] A method for operating a drive system is known from DE 10 2019 005 019 A1. Summary of the invention
[0012] It is therefore an object of the present invention to design a braking resistor in a compact and cost-effective manner.
[0013] This object is achieved according to the invention by a braking resistor according to the features specified in claim 1 .
[0014] In terms of the brake resistor, an important feature of the present invention is that the brake resistor has a single flat plate.
[0015] In particular, the respective individual flap has a length arranged in the longitudinal direction which is greater than the width of the individual flap, in particular greater than the width of the individual flap measured in the transverse direction, i.e. perpendicularly to the longitudinal direction, in particular wherein the width is greater than the flap thickness of the individual flap,
[0016] wherein the respective single flat sheet has a first transverse slot and a second transverse slot which are arranged successively in the longitudinal direction and are spaced apart from each other,
[0017] In particular, wherein the first transverse slot and the second transverse slot are oriented parallel to each other and extend in the transverse direction, ie perpendicularly to the longitudinal direction,
[0018] wherein the first transverse slot extends into the single flat sheet from the right edge of the corresponding single flat sheet as viewed in the longitudinal direction,
[0019] wherein the second transverse slot extends into the single flat sheet from the left edge of the corresponding single flat sheet as viewed in the longitudinal direction,
[0020] wherein, viewed in the longitudinal direction, the first transverse slots and the second transverse slots are arranged successively and respectively alternately,
[0021] In particular, the area covered by the first transverse slot overlaps the area covered by the second transverse slot in a transverse direction, wherein the transverse direction is oriented perpendicularly to the longitudinal direction.
[0022] The advantage here is that the material course is meander-shaped and thus the longest possible line length is achieved in a space-saving manner.
[0023] In an advantageous embodiment, the respective individual flat plates have a region extending in a meandering manner in the longitudinal direction by means of the transverse slots. The advantage here is that efficient utilization of this area can be achieved in a simple manner.
[0024] In an advantageous embodiment, the individual plates are made of flat steel sheets, in particular rectangular flat steel sheets. This has the advantage that chrome steel can be used as the material. Although the rigidity of the individual steels is lower than that of stainless steel, the bent edges can stabilize the individual plates. In this way, the braking resistor can be made of cost-effective steel and still have a lower vibration potential and thus quieter operation, in particular when operated on converter-fed motors.
[0025] In an advantageous embodiment, the single flat sheet is made as a stamped-bent part. This has the advantage that simple manufacturing can be achieved. Preferably, full stamping is performed so that no waste material is generated during the stamping-bending process or only very little waste material is generated during the stamping.
[0026] In an advantageous embodiment, the edge region of the single flat plate which delimits the corresponding transverse slot in the longitudinal direction at the front is bent by a first angle, in particular as a fold. This has the advantage that the rigidity of the single flat plate is increased and thus low-noise operation can be achieved.
[0027] In an advantageous embodiment, the edge region of the individual flat sheet which delimits the respective transverse slot at the rear in the longitudinal direction is bent by a second angle, in particular as a fold. Advantageously, the strut formed in each case between two adjacent transverse slots has two folds spaced apart from one another, which have the corresponding bending angle value.
[0028] In an advantageous embodiment, the first angle value is equal to the second angle value, in particular so that the corresponding transverse slot is arranged centrally between the edge regions. In this case, it is advantageous that the strut formed in each case between two adjacent transverse slots has two spaced-apart folds with corresponding bending angle values. Due to the two equal bending angles, a particularly high stiffness can be achieved. As a result, the mechanical resonance frequency of the strut changes towards very high frequency values when the angle value is not zero but increases.
[0029] In an alternative advantageous embodiment, the first angle value differs from the second angle value, in particular by at least 20°. This has the advantage that the support formed between two adjacent transverse slots has two folds spaced apart from one another, which have corresponding bending angle values. Due to the different selection of the angle values, the first fold at the support has a different bending angle than the second fold. This can increase the rigidity of the support.
[0030] In an advantageous embodiment, the first angle value is at least 30° and at most 90°. The advantage here is that a particularly high rigidity can be achieved, since the rigidity is only slightly increased below 30°.
[0031] In an advantageous embodiment, the second angle value is at least 30° and at most 90°. The advantage here is that a particularly high rigidity can be achieved, since the rigidity is only slightly increased below 30°.
[0032] In an advantageous embodiment, the edge region is bent only on a single side of the corresponding transverse slot, in particular bent into a fold. The advantage here is that, due to the asymmetrical design of the support with only a fold formed on one side, a particularly high rigidity of the support of the single flat sheet can be achieved.
[0033] In an advantageous embodiment, the individual flat plates are made of sheet steel, which is in particular not a stainless steel plate. This has the advantage that a cost-effective material can be used which is less hard than stainless steel. This is because reinforcement can be achieved by means of the folded edges. Furthermore, the bending of the folded edges can be achieved with less energy expenditure than with stainless steel. Flat plates of different hardness can be used.
[0034] In an advantageous embodiment, the individual flat plates are made of sheet steel which has a lower hardness than stainless steel, in particular a stainless steel of identical geometry, and / or which has a greater magnetic permeability than stainless steel, in particular a stainless steel of identical geometry. This has the advantage that such materials can be used despite the higher magnetic permeability. This is because, although the magnetic field of the adjacent live support generates a greater force effect, this force effect generates stronger vibrations; however, the folded edge prevents the accumulation of vibrations and thus reduces the noise.
[0035] In an advantageous embodiment, each transverse slot opens into the environment at its first end, in particular the open end, and is designed to be closed at its second end, in particular the other end.
[0036] The transverse slot is rounded, in particular circular, at the second end.
[0037] This is achieved in particular by punching out a circular segment from the single flat sheet, in particular so that the corresponding edge region of the single flat sheet which delimits the corresponding transverse slot is delimited linearly at its edge facing the second end of the transverse slot, in particular due to the punched out circular segment. The advantage here is that the rigidity of the single flat sheet is further increased and the noise is thus reduced. Furthermore, by punching out the circular segment, the fold can be safely removed from the rounded edge region of the single flat sheet even during bending. Punching out the circular segment also changes the natural frequency of the single flat sheet and shifts it to a higher value. In this way, structure-borne noise is reduced and thus also the sound radiation.
[0038] An important feature of the drive system with a braking resistor is that the drive system has a motor, in particular a three-phase motor, which is powered by an inverter, and a rectifier.
[0039] In this case, the DC voltage-side connection of the rectifier is arranged in parallel with the DC voltage-side connection of the inverter and in parallel with a series circuit having a braking resistor and a controllable semiconductor switch, in particular a braking chopper, connected in series with the braking resistor. This has the advantage that the energy generated by the generator can be discharged from the intermediate circuit via the braking resistor in order to prevent a critical increase in the intermediate circuit voltage of the converter. The controllable semiconductor switch, in particular the braking chopper, is actuated using a pulse width modulated signal.
[0040] In an advantageous embodiment, the inverter has controllable semiconductor switches, the corresponding actuation signals of which are designed to be pulse-width modulated.
[0041] In this case, the pulse width modulation frequency of the activation signal of the brake chopper is oscillated and / or modulated in a frequency band, which in particular has a first frequency value, in particular, the frequency band has a bandwidth of more than 10% of the frequency value, in particular less than 50% of the frequency value. This has the advantage that structure-borne noise generated in the brake resistor, in particular in a single flat disc, is as low as possible.
[0042] Further advantages are given by the dependent claims. The invention is not limited to the feature combinations of the claims. For a person skilled in the art, in particular from the objectives proposed and / or by comparison with the prior art, other reasonable combinations of the claims and / or the features of the individual claims and / or the features of the description and / or the features of the drawings are apparent. BRIEF DESCRIPTION OF THE DRAWINGS
[0043] Now the present invention is described in detail according to the schematic diagram:
[0044] exist Figure 1 Detailed Description of the Invention The individual flat disc 3 of the braking resistor according to the invention is shown in an oblique view, wherein a fold 4 is provided on one side at the corresponding slots (1, 2).
[0045] exist Figure 2 A related top view is shown in FIG.
[0046] exist Figure 3 Shown in Figure 2 an area.
[0047] exist Figure 4 The single flat plate 3 of the second braking resistor according to the present invention is shown in an oblique view, wherein folded edges (20, 21) with different bending angles are respectively arranged on both sides at the corresponding slots (1, 2) and bent upwards.
[0048] exist Figure 5 A related top view is shown in FIG.
[0049] exist Figure 6 Shown in Figure 2 an area. DETAILED DESCRIPTION
[0050] like Figures 1 to 3 As shown, the length of the individual flat plate 3 is greater than three times the width of the individual flat plate 3 , and in particular greater than ten times the plate thickness of the individual flat plate 3 .
[0051] In the longitudinal direction in which the length is measured, the single flat sheet 3 has a transverse slot which extends alternately from the right edge or the left edge into the single flat sheet 3 , in particular discontinuously into the single flat sheet 3 .
[0052] In particular, the transverse slots which are formed straight are spaced apart from one another and are oriented in particular parallel to one another.
[0053] With the exception of the first and last transverse slots (1, 2), each transverse slot constructed from the right edge of the single flat sheet 3 is assigned a transverse slot formed from the left edge of the single flat sheet 3 as the nearest slot in the longitudinal direction and against the longitudinal direction.
[0054] The individual flat plates 3 are produced as punched-bent parts, wherein the transverse slots are punched and the regions of the individual flat plates 3 adjoining the respective transverse slots ( 1 , 2 ) at the front in the longitudinal direction are bent, in particular bent upwards.
[0055] In accordance with Figure 1 In an embodiment, the bend angle is approximately 90°.
[0056] In this way, a meander-like course of the material of the individual flat sheet 3 in the longitudinal direction is produced.
[0057] In a braking resistor, a plurality of such previously described individual plates 3 which are similarly or identically designed to one another are arranged parallel to one another as a stack, with electrical insulation arranged between them. The individual plates 3 are electrically connected in series to one another. Currents, especially high currents, flowing in a meandering manner through the series circuit of the individual plates 3 are prevented when mechanical vibrations of the individual plates 3 are excited, because the bent, especially upwardly bent, folds 4 increase the rigidity of the individual plates 3.
[0058] like Figure 1 As shown, a fold 4 is thus formed and arranged on one side at each transverse slot.
[0059] Each transverse slot is connected to the ambient air with its open end. At the other end, the corresponding transverse slot is designed to be closed, wherein the transverse slot is designed to be rounded, in particular circular, in this end area. The corresponding folded edge 4 is preferably bounded linearly at the corresponding end, because when punching to form the rounded end area of the transverse slot, the rounded area is punched out of the metal sheet. This area is preferably designed as a circular segment. Therefore, after punching, the straight cut leads to the recess formed by removing the circular segment. Here, the chord-shaped part of the circular segment is oriented in the longitudinal direction, in particular before bending. The single flat sheet 3 is then produced by bending the folded edge 4 during the punching-bending process.
[0060] In other exemplary embodiments according to the invention, the bending angle has a smaller value, in particular between 30° and 90°.
[0061] and Figure 1 Different, according to Figure 4 , Figure 5 and Figure 6In an embodiment, the corresponding fold (21, 22) is bent on both sides at each narrow groove, that is, in particular in the longitudinal direction, in front and in the back, in particular upward.
[0062] The rear fold 21 of the respective transverse slot 21 in the longitudinal direction, ie the first fold 21 , is bent in the same direction as the front fold 22 in the longitudinal direction, ie the second fold 22 .
[0063] In one embodiment, the bending angles of all first and second folds (21, 22) are of the same magnitude, in particular 90°. Alternatively, values of the bending angles between 30° and 90° can also be used for all folds (21, 22), wherein the flat sheet thickness is adjusted accordingly.
[0064] According to Figure 1 In contrast to the embodiment of the present invention, the cutout opens centrally, in particular symmetrically, into the recess which is designed as a circular segment.
[0065] Since the folded edges 21 and 22 are Figure 1 The fold edge 4 in the middle is narrow, so that a high rigidity can be achieved with a corresponding plate thickness and thus vibrations can be suppressed.
[0066] According to Figure 4 In different designs, the bending angles of the two folded edges 21 and 22 assigned to the corresponding transverse slots (1, 2) are different.
[0067] In accordance with Figure 4 In the embodiment of the present invention, the first fold 21 at the front in the longitudinal direction is bent vertically, and the second fold 22 at the rear in the longitudinal direction is configured to have a smaller bending angle value and / or is bent at a smaller bending angle value.
[0068] In other embodiments according to the present invention, the value of the bending angle of the first folded edge 21 is greater than the value of the bending angle of the second folded edge 22 .
[0069] In particular, the value of the bending angle of the first fold 21 is between 60° and 90°, and the value of the bending angle of the second fold 22 is between 30° and 60°.
[0070] Alternatively, the bending angles of the front and rear folds (21, 22) are opposite, ie the bending angle of the first fold 21 has a value between 30° and 60°, and the bending angle of the second fold 22 has a value between 60° and 90°.
[0071] The braking resistor is preferably used in the intermediate circuit of the converter. Here, the converter has a mains-powered rectifier, whose DC voltage-side connections are connected to the DC voltage-side connections of the inverter, and whose AC voltage-side connections supply power to the motor, in particular a three-phase motor.
[0072] In order to prevent a critical voltage value at the DC voltage-side connection of the inverter from being exceeded in the generator operating mode of the power plant, a series circuit connected in parallel with the rectifier is provided at the DC voltage-side connection of the inverter. The series circuit has at least a braking resistor and a controllable semiconductor switch connected in series with the braking resistor.
[0073] Electrical power can thus be output from the intermediate circuit to the braking resistor.
[0074] Preferably, the braking resistor is used in the intermediate circuit of a converter for feeding the electric machine. The converter has a mains supply rectifier for feeding the inverter. A series circuit is connected in parallel to the connection on the DC voltage side, which series circuit has a braking rectifier and a controllable semiconductor switch. Pulse width modulated actuation of one or more semiconductor switches of the converter induces mechanical vibrations of the single flat plate.
[0075] In other embodiments according to the invention, the single flat piece is not configured in a rectangular shape but in a square shape.
[0076] List of reference numerals:
[0077] 1First transverse slot
[0078] 2 Second transverse slot
[0079] 3 single flat piece
[0080] 4 Folding edge
[0081] 21 First fold
[0082] 22 Second fold
Claims
1. A brake resistor, the brake resistor having a single flat sheet, In particular, the respective individual flaps have a length arranged in the longitudinal direction which is greater than the width of the individual flaps, in particular greater than the width of the individual flaps measured in the transverse direction, ie perpendicularly to the longitudinal direction, in particular wherein: The width is greater than the thickness of a single flat sheet, It is characterized in that The respective single flat sheet has a first transverse slot and a second transverse slot which are arranged successively in the longitudinal direction and are spaced apart from each other, In particular, the first transverse slot and the second transverse slot are oriented parallel to each other and extend in a transverse direction, ie perpendicularly to the longitudinal direction, The first transverse slot extends into the single flat sheet from the right edge of the corresponding single flat sheet as viewed in the longitudinal direction, The second transverse slot extends into the single flat sheet from the left edge of the corresponding single flat sheet as viewed in the longitudinal direction, Viewed in the longitudinal direction, the first transverse slots and the second transverse slots are arranged successively and respectively alternately, In particular, the area covered by the first transverse slot overlaps with the area covered by the second transverse slot in a transverse direction, wherein the transverse direction is oriented perpendicularly to the longitudinal direction.
2. The braking resistor according to claim 1, characterized in that: The respective individual flat plate has a region extending in a meandering manner in the longitudinal direction by means of the transverse slots.
3. The brake resistor according to any one of the preceding claims, characterized in that The single flat piece is made of a flat steel plate, in particular a rectangular flat steel plate.
4. A braking resistor according to any one of the preceding claims, characterized in that A single flat sheet is produced as a stamped-bent part.
5. Braking resistor according to any one of the preceding claims, characterized in that The edge region of the individual flat blades which delimits the respective transverse slot at the front in the longitudinal direction is bent by a first angle, in particular in the form of a folded edge.
6. Braking resistor according to any one of the preceding claims, characterized in that The edge region of the individual flat blades which delimits the respective transverse slot at the rear in the longitudinal direction is bent by a second angle, in particular in the form of a folded edge.
7. Braking resistor according to any one of the preceding claims, characterized in that The first angle value is equal to the second angle value, in particular so that the corresponding transverse slot is arranged centrally between the edge regions, or, The first angle value differs from the second angle value, in particular deviates by at least 20°.
8. Braking resistor according to any one of the preceding claims, characterized in that The first angle value is at least 30° and at most 90°.
9. Braking resistor according to any one of the preceding claims, characterized in that The second angle value is at least 30° and at most 90°.
10. Braking resistor according to any one of the preceding claims, characterized in that The edge region is bent only on a single side of the respective transverse slot, in particular as a fold.
11. Braking resistor according to any one of the preceding claims, characterized in that The single flat sheet is made of iron material, cast iron material or steel plate, which is not stainless steel plate. and / or, The single flat sheet is made of an iron or steel plate, which has a lower hardness than a stainless steel plate, especially a stainless steel plate with the same geometric shape, and / or the iron or steel plate has a greater magnetic permeability than a stainless steel plate, especially a stainless steel plate with the same geometric shape.
12. Braking resistor according to any one of the preceding claims, characterized in that Each transverse slot opens into the environment at its first end, in particular the open end, and is designed to be closed at its second end, in particular the other end, The transverse slot is designed to be rounded, in particular circular, at the second end. This is achieved in particular by punching out a circular segment from the single flat sheet, in particular so that the respective edge region of the single flat sheet delimiting the respective transverse slot is linearly delimited at its edge facing the second end of the transverse slot, in particular due to the punched out circular segment.
13. A drive system having a brake resistor according to any one of the preceding claims, It is characterized in that The drive system comprises an electric motor, in particular a three-phase electric motor, which is powered by an inverter, and a rectifier. The DC voltage-side connections of the rectifier are arranged in parallel with the DC voltage-side connections of the inverter and in parallel with a series circuit having a braking resistor and a controllable semiconductor switch, in particular a braking chopper, connected in series with the braking resistor.
14. A drive system according to any one of the preceding claims, characterised in that The actuation signal of the controllable semiconductor switch, in particular the brake chopper, is designed to be pulse-width modulated. The pulse width modulation frequency of the control signal is oscillated and / or modulated in a frequency band which in particular has a first frequency value, in particular wherein the frequency band has a bandwidth greater than 10% of the frequency value, in particular less than 50% of the frequency value.
15. Drive system according to any one of the preceding claims, characterized in that The inverter has controllable semiconductor switches, the corresponding actuation signals of which are designed to be pulse-width modulated. The pulse width modulation frequency of the corresponding control signal is oscillated and / or modulated in a frequency band which in particular has the second frequency value, in particular wherein the frequency band has a bandwidth greater than 10% of the frequency value, in particular less than 50% of the frequency value.