CN111602330A - Electronic short-circuit braking device for electric motor - Google Patents
Electronic short-circuit braking device for electric motor Download PDFInfo
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- CN111602330A CN111602330A CN201980008616.4A CN201980008616A CN111602330A CN 111602330 A CN111602330 A CN 111602330A CN 201980008616 A CN201980008616 A CN 201980008616A CN 111602330 A CN111602330 A CN 111602330A
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- switching
- switching unit
- unit
- electric motor
- switching elements
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
- H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P3/00—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters
- H02P3/06—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters for stopping or slowing an individual dynamo-electric motor or dynamo-electric converter
- H02P3/18—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters for stopping or slowing an individual dynamo-electric motor or dynamo-electric converter for stopping or slowing an ac motor
- H02P3/22—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters for stopping or slowing an individual dynamo-electric motor or dynamo-electric converter for stopping or slowing an ac motor by short-circuit or resistive braking
Abstract
The invention relates to a brake device for an electric motor (12), comprising at least one first switching unit (14) having at least two switching elements (16, 18, 20) and at least one second switching unit (22) having at least two switching elements (24, 26, 28), wherein the first switching unit (14) and the second switching unit (22) are electrically conductively connected to the electric motor (12) at least for supplying power. It is proposed that the braking device (10) comprises at least one control and/or regulating unit (30) which is provided to alternately switch all switching elements (16, 18, 20) of the first switching unit (14) and all switching elements (24, 26, 28) of the second switching unit (22) for short-circuit braking of the electric motor (12).
Description
Background
DE 102014016822 a1 already proposes a brake device for an electric motor, which has at least one first switching unit with at least two switching elements and at least one second switching unit with at least two switching elements, wherein the first and second switching units are electrically conductively connected to the electric motor at least for the purpose of supplying power. In DE 102014016822 a1, for short-circuit braking of the electric motor, only a part of the switching elements of the first switching unit and a part of the switching elements of the second switching unit are switched alternately. In DE 102014016822 a1, no alternation between two switching cells occurs if all switching elements of one of the switching cells are converted into short-circuit braking.
Disclosure of Invention
The invention is based on a brake device for an electric motor, comprising at least one first switching unit having at least two switching elements and at least one second switching unit having at least two switching elements, wherein the first and second switching units are electrically conductively connected to the electric motor at least for supplying power.
It is proposed that the braking device comprises at least one control and/or regulating unit which is provided for alternately switching all switching elements of the first switching unit and all switching elements of the second switching unit for short-circuit braking of the electric motor.
The first switching unit and the second switching unit preferably together form a bridge circuit. The bridge circuit can be designed in particular as a B-4 bridge, a B-6 bridge, an H bridge, in particular as a B2 bridge with freewheeling diodes, or as another bridge circuit which is considered appropriate by the person skilled in the art. The electric motor can preferably be designed as a two-phase motor or as a three-phase motor. The first switching unit of the braking device according to the invention for a two-phase motor comprises in particular exactly two switching elements. The second switching unit of the braking device according to the invention for a two-phase motor comprises in particular exactly two switching elements. The first switching unit and the second switching unit of the brake device for a two-phase motor preferably form a B-4 bridge or an H-bridge. The first switching unit of the braking device according to the invention for a three-phase motor comprises in particular exactly three switching elements. The second switching unit of the brake device according to the invention for a three-phase motor comprises in particular exactly three switching elements. The first switching unit and the second switching unit of the brake device for a three-phase motor preferably form a B-6 bridge or an H-bridge.
Preferably, the first switching unit and the second switching unit are provided for supplying the electric motor with electric energy, in particular from an energy source, such as a mains voltage source, a battery or the like, in particular via the switching elements of the two switching units. Preferably, the switching elements of the first and second switching units, in particular of both switching units, are provided to connect the electric motor to the energy source in an electrically conductive manner, in particular for the purpose of current supply. The switching element preferably has at least two states, particularly preferably exactly two states. The switching element in the first, non-switched-on state in particular inhibits a current flow through the switching element. The switching element in the second switched-on state allows, in particular, a current to flow through the switching element. Preferably, the control and/or regulation of the electric motor can be carried out by specifically switching the switching element, in particular between two states of the switching element. The switching element is preferably switched by the control and/or regulating unit. A "control and/or regulating unit" is to be understood to mean, in particular, a unit having at least one control electronics. The term "control electronics" is to be understood to mean, in particular, a unit having a processor unit and a memory unit, as well as an operating program stored in the memory unit. The control and/or regulating unit may be designed in particular as a microcomputer. Alternatively, it is conceivable for the control and/or regulating unit to be designed as an ASIC (application specific integrated circuit), in particular as a gate driver. "provided" is to be understood in particular to mean specially programmed, designed and/or equipped. An object is provided for a specific function, in particular in the sense that the object fulfills and/or performs the specific function in at least one application and/or operating state.
For short-circuit braking of the electric motor, in particular the windings of the electric motor, are preferably electrically short-circuited. Preferably, a counter electromotive force acts when the motor is short-circuited, which counter electromotive force causes, in particular, a short-circuit current. The braking of the electric motor by short-circuit braking preferably takes place with a shorter duration, in particular until the motor is in a standstill, than by interrupting the current supply to the electric motor or than by making use of the residual energy by reducing the PWM control signal (pulse width modulated control signal). Preferably, the short-circuit braking is performed alternately by, in particular, at least substantially simultaneously switching on all switching elements of the first switching unit and by, in particular, at least substantially simultaneously switching on all switching elements of the second switching unit. In this context, "switching on the switching element" is to be understood in particular to mean switching the switching element from the non-switched-on state to the switched-on state of the switching element. The short-circuit current preferably flows through the switched-on switching element, in particular until a standstill of the electric motor has been reached. For short-circuit braking of the electric motor, the control and/or regulating unit is preferably provided for switching all switching elements of the first switching unit, in particular at least substantially simultaneously. Preferably, the control and/or regulating unit is provided for switching all switching elements of the switching unit simultaneously or, in particular if the control and/or regulating unit is designed as a two-phase or three-phase gate drive, switching all switching elements of the switching unit one after the other, in particular at such short time intervals: so that the motor behaves as if the switching elements are switched simultaneously. For short-circuit braking of the electric motor, the control and/or regulating unit is preferably provided for switching all switching elements of the first switching unit back to the non-switched-on state, in particular at least substantially simultaneously, and all switching elements of the second switching unit on, in particular at least substantially simultaneously, in particular after a defined time duration. Preferably, the control and/or regulating unit is provided for switching all switching elements of the second switching unit back to the non-switched-on state, in particular at least substantially simultaneously, in particular after a defined time duration. Preferably, the control and/or regulating unit is provided for periodically repeatedly switching on all switching elements of the first switching unit and all switching elements of the second switching unit alternately, in particular until a standstill state of the electric motor.
The configuration of the braking device according to the invention advantageously enables an efficient and in particular faster braking of the electric motor than by interrupting the current supply to the electric motor or than by making use of the residual energy by reducing the PWM control signal. In particular, the load on the switching element can be advantageously reduced compared to short-circuit braking by means of only a single switching unit. Advantageously, switching elements with a lower resistance and therefore particularly more cost-effective can be installed. Advantageously, a durable, safe and cost-effective braking device may be provided.
Furthermore, it is proposed that each of the switching elements of the first switching unit and each of the switching elements of the second switching unit are each electrically conductively connected to a phase of the electric motor. The first switching unit preferably has a number of switching elements corresponding to the number of phases of the electric motor. The second switching unit preferably has a number of switching elements corresponding to the number of phases of the electric motor. Preferably, each of the switching element of the first switching unit and the switching element of the second switching unit is electrically conductively connected to a phase of the electric motor via a common electrical line. The phase of the electric motor is electrically conductively connected, in particular via an electrical line, between the output of the switching element of the second switching unit and the input of the switching element of the first switching unit. The switching element of the first switching unit and the switching element of the second switching unit are preferably electrically connected in series with each other. Preferably, the two switching elements of the first and second switching units are electrically connected in parallel with the other switching element pairs of the first and second switching units. Each pair of switching elements of the first and second switching units is electrically conductively connected in particular to a phase of the electric motor which is different from the other pairs of switching elements of the first and second switching units. The following circuitry may advantageously be provided: the circuit can realize the current supply of the motor and also realize the short-circuit braking of the motor. A separate circuit for braking the electric motor can advantageously be dispensed with. A cost-effective braking device can advantageously be provided.
It is further proposed that the switching element of the first switching unit and the switching element of the second switching unit are embodied as semiconductor switches. The switching elements of the first switching unit and the switching elements of the second switching unit may be embodied in particular as bipolar transistors, MOSFETs (metal oxide semiconductor field effect transistors), IGBTs (insulated gate bipolar transistors) or other semiconductor switches which are considered to be expedient by the person skilled in the art. All switching elements of the first switching unit and all switching elements of the second switching unit are preferably designed as semiconductor switches of identical construction. The switching element may preferably be turned on by applying a voltage and/or a current to a gate electrode of the switching element. The control and/or regulating unit is provided in particular for applying a voltage and/or a current to the gate electrode of the switching element in order to switch the switching element on. The control and/or regulating unit is preferably provided for switching the switching element from the on-state back to the non-on-state by interrupting the voltage and/or the current on the gate electrode of the switching element. It is advantageously possible to achieve an effective switching of the switching element of the first switching unit and the switching element of the second switching unit.
It is further proposed that the control and/or regulating unit is provided for switching the first switching unit and the second switching unit between two successive electrical short circuits of the electric motor to the non-switched state of the switching unit. The control and/or regulating unit is provided in particular for switching all switching elements of the first switching unit and all switching elements of the second switching unit between two mutually successive electrical short circuits of the electric motor into the non-switched state of the switching elements. Preferably, in the non-switched-on state of the switching unit, the commutation of the electric motor is effected by means of diodes, for example intrinsic diodes of the switching elements in the form of MOSFETs or the like. In particular after commutation, current flow is inhibited between the two electrical short circuits. The duration of the switch unit in the non-switched-on state between two electrical short circuits of the electric motor is shorter than the duration of the electrical short circuit of the electric motor, preferably at least 50% shorter, particularly preferably at least 75% shorter. The switching on of all switching elements of the first switching unit and the switching on of all switching elements of the second switching unit may advantageously be separated in time. The supply of current to the electric motor during a braking process can advantageously be prevented and an effective braking process can be achieved.
It is furthermore proposed that the control and/or regulating unit is provided for adjusting the frequency of the alternation of the electrical short-circuits. The alternating frequency of the electrical short-circuit is in particular the frequency at which the control and/or regulating unit switches between the switching elements, in particular all the switching elements, of the first switching unit and the switching elements, in particular all the switching elements, of the second switching unit. Preferably, the user and/or the manufacturer of the braking device can specify, in particular be programmed into, the control and/or regulating unit electrical short-circuit alternation frequency adjusted by the control and/or regulating unit. The alternating frequency has in particular a value of at least 0.1kHz, preferably a value of 1kHz, particularly preferably a value of at least 10 kHz. Preferably, the transient thermal resistance of the switching element, in particular the thermal resistance between the semiconductor chip and the housing of the switching element, depends on the alternating frequency. The transient thermal resistance of the switching element is particularly reduced when the alternating frequency is increased. The amount of energy which is made available for the residual energy during the braking process preferably depends on this alternating frequency. The amount of energy available for surplus energy increases especially as the frequency of alternation increases. Advantageously, the frequency of alternation of the electrical short-circuits can be adjusted. The component load can advantageously be controlled by alternating the frequency. Advantageously, an effective and durable braking device may be provided.
It is furthermore proposed that the control and/or regulating unit is provided for adjusting the duration of a braking cycle during which the first switching unit and the second switching unit each short-circuit the electric motor once. The braking cycle comprises in particular the switching elements of the first switching unit (preferably all switching elements) being switched on, the current supply of the electric motor being interrupted, the switching elements of the second switching unit (preferably all switching elements) being switched on and another interruption of the current supply of the electric motor. The control and/or regulating unit is preferably provided for adjusting the duration of all braking cycles of the braking process in an identical manner. Alternatively, it is conceivable for the control and/or regulating unit to be provided for varying the duration of the different braking cycles during the braking process. The control and/or regulating unit is preferably provided for adjusting the duration of the different phases of the braking cycle. A complete control and/or regulation of the braking process can advantageously be achieved. Advantageously, the braking process can be flexibly adapted to the purpose of use. Advantageously, an effective braking device can be provided.
Furthermore, it is proposed that the control and/or regulating unit is provided for controlling and/or regulating the first and second switching units in such a way that they short-circuit the electric motor for the same long time duration during the braking cycle. The control and/or regulating unit preferably switches the switching elements of the first switching unit, preferably all switching elements and the switching elements of the second switching unit, preferably all switching elements, in such a way that the switching elements of the first switching unit, preferably all switching elements and the switching elements of the second switching unit, preferably all switching elements, are in the on state of the switching elements for the same duration, as seen over the duration of the braking cycle. Preferably, the current flowing through the switching element of the first switching unit during a braking period corresponds to the current flowing through the switching element of the second switching unit during a braking period. A uniform loading of the switching elements of the first switching unit and the switching elements of the second switching unit can advantageously be achieved. Advantageously, a durable braking device can be provided.
Furthermore, it is proposed that the control and/or regulating unit is provided for controlling and/or regulating the first and second switching units in such a way that they short-circuit the electric motor for different durations during the braking cycle. The control and/or regulating unit preferably switches the switching elements of the first switching unit, preferably all switching elements, and the switching elements of the second switching unit, preferably all switching elements, in such a way that the switching elements of the first switching unit, preferably all switching elements, and the switching elements of the second switching unit, preferably all switching elements, are in the on state of the switching elements for different durations, as seen over the duration of the braking cycle. Preferably, the current flowing through the switching element of the first switching unit during a braking period is different from the current flowing through the switching element of the second switching unit during a braking period. The braking period can advantageously be adapted to the application purpose of the braking device. Advantageously, a brake device that can be used flexibly can be provided.
The invention also relates to a method for operating a brake system, in particular a brake system according to the invention.
It is proposed that, in particular in at least one method step, all switching elements of the first switching unit and all switching elements of the second switching unit are switched alternately for short-circuit braking of the electric motor. Preferably, all switching elements of the first switching unit and all switching elements of the second switching unit are switched alternately by means of the control and/or regulating unit. Advantageously, a safe and protective member braking method may be provided.
The invention also relates to a machine tool having at least one electric motor and at least one braking device according to the invention. The electric motor can be designed in particular as a two-phase motor or as a three-phase motor. The power tool can be configured, in particular, as a circular saw, jigsaw, drilling machine, angle grinder, lawn mower, brush cutter, cross-cut saw, circular bench saw, band saw or other power tools which are considered appropriate by the person skilled in the art. The power tool preferably comprises further components which are necessary in particular for operating the power tool. The power tool can comprise, in particular, at least one energy supply unit (e.g., a battery, a power cable, etc.), a tool chuck, a housing and/or other components that are considered appropriate by the person skilled in the art. Advantageously, a durable, user-safe and cost-effective machine tool can be provided.
The braking device according to the invention, the method according to the invention and/or the machine tool according to the invention should not be limited to the above-described applications and exemplary embodiments. The braking device according to the invention, the method according to the invention and/or the machine tool according to the invention may in particular have a different number of individual elements, components and units and method steps than those mentioned above in order to achieve the functional manner described herein. Furthermore, within the range of values specified in the present disclosure, values within the limits mentioned should also be regarded as being disclosed and can be used at will.
Drawings
Other advantages are derived from the following description of the figures. Embodiments of the invention are illustrated in the drawings. The figures, description, and claims contain many combined features. The person skilled in the art will also expediently consider these features individually and combine them into meaningful further combinations.
In the drawings:
fig. 1 shows a schematic representation of a power tool according to the invention;
fig. 2 shows a schematic illustration of a braking device according to the invention with an unengaged switching element;
fig. 3 shows a schematic illustration of a brake device with a switching element of a first switching unit;
fig. 4 shows a brake device with a switching element of a second switching unit in a schematic view;
FIG. 5 shows a braking cycle in a schematic diagram;
fig. 6 shows a further braking cycle in a schematic representation;
fig. 7 shows the effect of the alternating frequency on the transient thermal resistance in a schematic diagram.
Detailed Description
Fig. 1 shows a machine tool 38 in a schematic representation. The power tool 38 is designed as a hand-held power tool. The machine tool 38 is configured as a drill. Alternatively, it is conceivable for the power tool 38 to be designed as a circular saw, jigsaw, angle grinder, lawn mower, brush cutter, cross-cut saw, circular table saw, band saw or the like. The power tool 38 has a housing unit 40. The machine tool 38 has an electric motor 12. The motor 12 is configured as a three-phase motor. Alternatively, it is conceivable for the electric motor 12 to be designed as a two-phase motor. The motor 12 is disposed within the housing unit 40. The electric motor 12 is provided for driving a plug-in tool 42 of the power tool 38. The insertion tool 42 is configured as a drill bit. The insertion tool 42 is partially disposed within a tool chuck 44 of the machine tool 38. The machine tool 38 has a braking device 10 for the electric motor 12. The braking device 10 is arranged in a housing unit 40 of the machine tool 38.
Fig. 2 shows a schematic illustration of the brake system 10 with the switching elements 16, 18, 20, 24, 26, 28 not switched on. The braking device 10 includes a first switching unit 14. The first switching unit 14 has a first switching element 16 of the first switching unit 14, a second switching element 18 of the first switching unit 14 and a third switching element 20 of the first switching unit 14. The braking device 10 includes a second switching unit 22. The second switching unit 22 has a first switching element 24 of the second switching unit 22, a second switching element 26 of the second switching unit 22 and a third switching element 28 of the second switching unit 22. The first switching unit 14 and the second switching unit 22 constitute a bridge circuit. The bridge circuit formed by the first switching unit 14 and the second switching unit 22 is configured as a B-6 bridge. Alternatively, it is conceivable for the bridge circuit formed by the first switching unit 14 and the second switching unit 22 to be designed as an H-bridge. The first switching unit 14 and the second switching unit 22 are connected to the electric motor 12 in an electrically conductive manner for the purpose of current supply. Each of the switching elements 16, 18, 20 of the first switching unit 14 and each of the switching elements 24, 26, 28 of the second switching unit 22 is electrically conductively connected to a respective one of the phases 32, 34, 36 of the electric motor 12. The first switching element 16 of the first switching unit 14 and the first switching element 24 of the second switching unit 22 are electrically conductively connected to the first phase 32 of the electric motor 12 via a first electrical line 46. The first switching element 16 of the first switching unit 14 and the first switching element 24 of the second switching unit 22 are electrically connected in series and constitute a first switching element pair. The second switching element 18 of the first switching unit 14 and the second switching element 26 of the second switching unit 22 are electrically conductively connected to the second phase 34 of the electric motor 12 by a second electrical line 48. The second switching element 18 of the first switching unit 14 and the second switching element 26 of the second switching unit 22 are electrically connected in series and constitute a second switching element pair. The third switching element 20 of the first switching unit 14 and the third switching element 28 of the second switching unit 22 are electrically conductively connected to the third phase 36 of the electric motor 12 via a third electrical line 50. The third switching element 20 of the first switching unit 14 and the third switching element 28 of the second switching unit 22 are electrically connected in series and constitute a third switching element pair. The first switching element pair, the second switching element pair, and the third switching element pair are electrically connected in parallel with each other.
The switching elements 16, 18, 20 of the first switching unit 14 and the switching elements 24, 26, 28 of the second switching unit 22 are embodied as semiconductor switches. The switching elements 16, 18, 20 of the first switching unit 14 and the switching elements 24, 26, 28 of the second switching unit 22 are embodied as semiconductor switches of identical construction. The switching elements 16, 18, 20 of the first switching unit 14 and the switching elements 24, 26, 28 of the second switching unit 22 are configured as bipolar transistors. Alternatively, it is conceivable for the switching elements 16, 18, 20 of the first switching cell 14 and the switching elements 24, 26, 28 of the second switching cell 22 to be designed as MOSFETs or IGBTs. The switching elements 16, 18, 20 of the first switching unit 14 and the switching elements 24, 26, 28 of the second switching unit 22 are switchable to supply electrical energy to the electric motor 12 via the energy source 52. By switching on the switching elements 16, 18, 20 of the first switching unit 14 and the switching elements 24, 26, 28 of the second switching unit 22, the electric motor 12 can be connected to the energy source 52 in an electrically conductive manner. Energy source 52 is configured as a battery. Alternatively, it is conceivable for energy source 52 to be designed as a grid voltage source.
The braking device 10 has a control and/or regulating unit 30. The control and/or regulating unit 30 is designed as a microcomputer. Alternatively, it is conceivable for the control and/or regulating unit 30 to be designed as an ASIC. The control and/or regulating unit 30 is provided for alternately switching all switching elements 16, 18, 20 of the first switching unit 14 and all switching elements 24, 26, 28 of the second switching unit 22 for short-circuit braking of the electric motor 12. The switching elements 16, 18, 20 of the first switching unit 14 and the switching elements 24, 26, 28 of the second switching unit 22 are shown in an unengaged state. In the non-switched-on state, the current flowing through the switching elements 16, 18, 20 of the first switching unit 14 and the switching elements 24, 26, 28 of the second switching unit 22 is inhibited. In the on state of the switching elements 16, 18, 20 of the first switching unit 14 and the switching elements 24, 26, 28 of the second switching unit 22, a current may flow through the switching elements 16, 18, 20 of the first switching unit 14 and the switching elements 24, 26, 28 of the second switching unit 22. The control and/or regulating unit 30 is electrically conductively connected via a fourth electrical line 54 to a first gate electrode 56 of the first electrical switch element 16 of the first switching unit 14. The control and/or regulating unit 30 is electrically conductively connected via a fifth electrical line 58 to a second gate electrode 60 of the second electrical switch element 18 of the first switching unit 14. The control and/or regulating unit 30 is electrically conductively connected to a third gate electrode 64 of the third electrical switch element 20 of the first switch unit 14 via a sixth electrical line 62. The control and/or regulating unit 30 is electrically conductively connected to a fourth gate electrode 68 of the first electrical switch element 24 of the second switch unit 22 via a seventh electrical line 66. The control and/or regulating unit 30 is electrically conductively connected via an eighth electrical line 70 to a fifth gate electrode 72 of the second electrical switching element 26 of the second switching unit 22. The control and/or regulating unit 30 is electrically conductively connected via a ninth electrical line 74 to a sixth gate electrode 76 of the third electrical switching element 28 of the second switching unit 22. In order to switch on the switching elements 16, 18, 20 of the first switching unit 14 and the switching elements 24, 26, 28 of the second switching unit 22, the control and/or regulating unit 30 is provided for applying a current to the gate electrodes 56, 60, 64 of the switching elements 16, 18, 20 of the first switching unit 14 and to the gate electrodes 68, 72, 76 of the switching elements 24, 26, 28 of the second switching unit 22.
Fig. 3 shows the brake system 10 with the switching elements 16, 18, 20 of the first switching unit 14 in a schematic representation. All switching elements 16, 18, 20 of the first switching unit 14 are switched by a control and/or regulating unit 30. The electric motor 12 is short-circuited by the switched-on switching elements 16, 18, 20 of the first switching unit 14. A counter electromotive force acts which causes a first short-circuit current 78 through the switching elements 16, 18, 20 of the first switching unit 14. The electric motor 12 is braked by short-circuit braking by means of the first switching unit 14. The state of the brake apparatus 10 shown in fig. 3 corresponds to the first phase 80 of the braking cycle. The second phase 82 of the braking cycle occurs between two successive electrical shorts of the motor 12. The control and/or regulating unit 30 is provided for switching the first switching unit 14 and the second switching unit 22 between two mutually successive electrical short circuits of the electric motor 12 into the non-switched state of the switching units 14, 22. The control and/or regulating unit 30 is provided for switching all switching elements 16, 18, 20 of the first switching unit 14 and all switching elements 24, 26, 28 of the second switching unit 22 between two mutually successive electrical short circuits of the electric motor 12 into the non-switched state of the switching elements 16, 18, 20, 24, 26, 28 (see fig. 2). The commutation of the electric motor 12 takes place in the non-switched-on state of the switching units 14, 22 by means of diodes, not shown in detail. After commutation, the current flow is inhibited between the two electrical short circuits. The duration of the switching unit 14, 22 in the non-switched-on state between two electrical short circuits of the electric motor 12 is shorter than the duration of the electrical short circuit of the electric motor 12.
Fig. 4 shows the brake system 10 with the switched-on switching elements 24, 26, 28 of the second switching unit 22 in a schematic representation. All switching elements 24, 26, 28 of the second switching unit 22 are switched on by the control and/or regulating unit 30. The electric motor 12 is short-circuited by the switched-on switching elements 24, 26, 28 of the second switching unit 22. A counter electromotive force acts which causes a second short-circuit current 84 through the switching elements 24, 26, 28 of the second switching unit 22. The electric motor 12 is braked by short-circuit braking by means of the second switching unit 22. The state of the brake apparatus 10 shown in fig. 4 corresponds to the third phase 86 of the braking cycle. A fourth phase 88 of the braking cycle, following the third phase 86 of the braking cycle, corresponds to the second phase 82 of the braking cycle.
Fig. 5 shows a brake cycle in a schematic representation. A first graph 90 is shown having a first abscissa axis 92 and a first ordinate axis 94. The duration is plotted on a first abscissa axis 92. On the first ordinate axis 94, the switching states of the switching elements 16, 18, 20, 24, 26, 28 are plotted. The switching states of the switching elements 16, 18, 20 of the first switching unit 14 are plotted on a positive portion 96 of the first ordinate axis 94. The switching states of the switching elements 24, 26, 28 of the second switching unit 22 are plotted on a negative part 98 of the first ordinate axis 94. The control and/or regulating unit 30 is provided for adjusting the duration of the braking period during which the first switching unit 14 and the second switching unit 22 respectively short-circuit the electric motor 12 once. The control and/or regulating unit 30 is provided for controlling and/or regulating the first switching unit 14 and the second switching unit 22 in such a way that the first switching unit 14 and the second switching unit 22 short-circuit the electric motor 12 for the same duration during a braking cycle. The duration of the first phase 80 of the braking cycle, in which all switching elements 16, 18, 20 of the first switching unit 14 are switched on, corresponds to the duration of the third phase 86 of the braking cycle, in which all switching elements 24, 26, 28 of the second switching unit 22 are switched on. The duration of the second phase 82 of the braking cycle corresponds to the duration of the fourth phase 88 of the braking cycle. In the second phase 82 of the braking cycle and the fourth phase 88 of the braking cycle, the first switching unit 14 and the second switching unit 22 are in an unengaged state. In the second phase 82 of the braking cycle and in the fourth phase 88 of the braking cycle, the control and/or regulating unit 30 switches all switching elements 16, 18, 20 of the first switching unit 14 and all switching elements 24, 26, 28 of the second switching unit 22 to the non-switched-on state.
Fig. 6 shows a further braking cycle in a schematic representation. The control and/or regulating unit 30 is provided for controlling and/or regulating the first switching unit 14 and the second switching unit 22 in such a way that the first switching unit 14 and the second switching unit 22 short-circuit the electric motor 12 for different durations during the further braking cycle. The duration of the first phase 80 of the further braking cycle, in which all switching elements 16, 18, 20 of the first switching unit 14 are switched on, is longer than the duration of the third phase 86 of the further braking cycle, in which all switching elements 24, 26, 28 of the second switching unit 22 are switched on. The duration of the first phase 80 of the further braking cycle, in which all switching elements 16, 18, 20 of the first switching unit 14 are switched on, is twice as long as the duration of the third phase 86 of the further braking cycle, in which all switching elements 24, 26, 28 of the second switching unit 22 are switched on. The duration of the second phase 82 of the further braking cycle corresponds to the duration of the fourth phase 88 of the further braking cycle. In the second phase 82 of the further braking cycle and in the fourth phase 88 of the further braking cycle, the first switching unit 14 and the second switching unit 22 are in the non-switched-on state. In the second phase 82 of the further braking cycle and in the fourth phase 88 of the further braking cycle, the control and/or regulating unit 30 switches all switching elements 16, 18, 20 of the first switching unit 14 and all switching elements 24, 26, 28 of the second switching unit 22 to the non-switched state.
Fig. 7 illustrates the effect of the alternating frequency of the electrical short-circuit on the transient thermal resistance of the switching elements 16, 18, 20, 24, 26, 28. A second graph 100 is shown having a second abscissa axis 102 and a second ordinate axis 104. The second graph 100 is constructed log-logarithmically. On the second axis of abscissa 102, the on-times of the switching elements 16, 18, 20 of the first switching unit 14 or the switching elements 24, 26, 28 of the second switching unit 22 are plotted. The on-times of the switching elements 16, 18, 20 of the first switching unit 14 or the switching elements 24, 26, 28 of the second switching unit 22 substantially correspond to the reverse alternation frequency of the electrical short circuit. On the second axis of ordinates 104, the transient thermal resistance of the switching elements 16, 18, 20, 24, 26, 28 is plotted as the thermal resistance between the chip and the housing of the switching elements 16, 18, 20, 24, 26, 28. The control and/or regulating unit 30 is arranged for adjusting the alternating frequency of the electrical short-circuits. The transient thermal resistance of the switching elements 16, 18, 20, 24, 26, 28 depends on the alternating frequency of the electrical short-circuit. The higher the frequency of alternation of the electrical short-circuits, the lower the transient thermal resistance of the switching elements 16, 18, 20, 24, 26, 28. The transient thermal resistance of the switching elements 16, 18, 20, 24, 26, 28 is higher at a first point 106 corresponding to an alternating frequency of 1kHz than at a second point 108 corresponding to an alternating frequency of 10 kHz. The transient thermal resistance of the switching elements 16, 18, 20, 24, 26, 28 is twice as high at a first point 106 corresponding to a 1kHz alternating frequency as at a second point 108 corresponding to a 10kHz alternating frequency.
The method for operating the brake device 10 is described next. In at least one method step, all switching elements 16, 18, 20 of the first switching unit 14 and all switching elements 24, 26, 28 of the second switching unit 22 are switched alternately for short-circuit braking of the electric motor 12. With regard to the further method steps of the method for operating the brake system 10, reference may be made to the previous description of the brake system 10, since this description is likewise applicable to this method, and therefore all features relating to the brake system 10 are also to be regarded as being disclosed with regard to the method for operating the brake system 10.
Claims (10)
1. A braking device for an electric motor (12), having at least one first switching unit (14) having at least two switching elements (16, 18, 20) and at least one second switching unit (22) having at least two switching elements (24, 26, 28), wherein the first switching unit (14) and the second switching unit (22) are connected in an electrically conductive manner to the electric motor (12) at least for the purpose of current supply, characterized by at least one control and/or regulating unit (30) which is provided to alternately switch all switching elements (16, 18, 20) of the first switching unit (14) and all switching elements (24) of the second switching unit (22) for short-circuit braking of the electric motor (12), 26, 28).
2. A braking device according to claim 1, characterized in that each of the switching elements (16, 18, 20) of the first switching unit (14) and each of the switching elements (24, 26, 28) of the second switching unit (22) is electrically conductively connected with one phase (32, 34, 36) of the electric motor (12), respectively.
3. A braking device according to claim 2, characterized in that the switching elements (16, 18, 20) of the first switching unit (14) and the switching elements (24, 26, 28) of the second switching unit (22) are configured as semiconductor switches.
4. A braking device according to any one of the foregoing claims, characterised in that the control and/or regulating unit (30) is provided for switching the first switching unit (14) and the second switching unit (22) to the non-switched-on state of the switching units (14, 22) between two mutually successive electrical short circuits of the electric motor (12).
5. Braking apparatus according to any one of the preceding claims, characterized in that the control and/or regulating unit (30) is provided for adjusting the frequency of alternation of the electrical short-circuits.
6. A braking device according to any one of the foregoing claims, characterised in that the control and/or regulating unit (30) is provided for adjusting the duration of a braking cycle during which the first switching unit (14) and the second switching unit (22) short-circuit the electric motor (12) once, respectively.
7. A braking device according to claim 6, characterized in that the control and/or regulating unit (30) is provided for controlling and/or regulating the first switching unit (14) and the second switching unit (22) in such a way that the first switching unit (14) and the second switching unit (22) short-circuit the electric motor (12) for the same duration during a braking cycle.
8. A braking device according to claim 6, characterized in that the control and/or regulating unit (30) is provided for controlling and/or regulating the first switching unit (14) and the second switching unit (22) in such a way that the first switching unit (14) and the second switching unit (22) short-circuit the electric motor (12) for different durations during a braking cycle.
9. A method for operating a brake device, in particular a brake device (10) according to one of the preceding claims, characterized in that for short-circuit braking of the electric motor (12), all switching elements (16, 18, 20) of the first switching unit (14) and all switching elements (24, 26, 28) of the second switching unit (22) are switched alternately.
10. Machine tool having at least one electric motor (12) and at least one braking device (10) according to one of claims 1 to 8.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102018200513.3 | 2018-01-15 | ||
| DE102018200513.3A DE102018200513A1 (en) | 2018-01-15 | 2018-01-15 | braking device |
| PCT/EP2019/050209 WO2019137865A1 (en) | 2018-01-15 | 2019-01-07 | Electronic short-circuit brake device for electric motors |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111602330A true CN111602330A (en) | 2020-08-28 |
Family
ID=65003399
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201980008616.4A Pending CN111602330A (en) | 2018-01-15 | 2019-01-07 | Electronic short-circuit braking device for electric motor |
Country Status (3)
| Country | Link |
|---|---|
| CN (1) | CN111602330A (en) |
| DE (1) | DE102018200513A1 (en) |
| WO (1) | WO2019137865A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022099669A1 (en) * | 2020-11-16 | 2022-05-19 | 博世电动工具（中国）有限公司 | Electric tool and three-phase electric motor control device and method thereof |
| WO2022170548A1 (en) * | 2021-02-10 | 2022-08-18 | Techtronic Cordless Gp | Device and method for motor braking |
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| US6118241A (en) * | 1997-11-25 | 2000-09-12 | Kollmorgen Corporation | Dynamic braking system for electric motors |
| CN101610056A (en) * | 2008-06-16 | 2009-12-23 | 通用电气公司 | The method and system that is used for dynamic motor braking |
| EP2433757A2 (en) * | 2010-09-28 | 2012-03-28 | Black & Decker Inc. | Method and system for electronic braking of a motor |
| JP2016158464A (en) * | 2015-02-26 | 2016-09-01 | ミネベア株式会社 | Brushless motor drive control device and drive control method |
| US20170234484A1 (en) * | 2016-02-12 | 2017-08-17 | Black & Decker Inc. | Electronic braking for a power tool having a brushless motor |
| US20180013360A1 (en) * | 2016-07-06 | 2018-01-11 | Black & Decker Inc. | Electronic braking of brushless dc motor in a power tool |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE112014003296T5 (en) * | 2013-07-18 | 2016-04-21 | Panasonic Intellectual Property Management Co., Ltd. | Washing machine |
| JP6155175B2 (en) | 2013-11-18 | 2017-06-28 | 株式会社マキタ | Electric tool braking device |
-
2018
- 2018-01-15 DE DE102018200513.3A patent/DE102018200513A1/en active Pending
-
2019
- 2019-01-07 CN CN201980008616.4A patent/CN111602330A/en active Pending
- 2019-01-07 WO PCT/EP2019/050209 patent/WO2019137865A1/en active Application Filing
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6118241A (en) * | 1997-11-25 | 2000-09-12 | Kollmorgen Corporation | Dynamic braking system for electric motors |
| CN101610056A (en) * | 2008-06-16 | 2009-12-23 | 通用电气公司 | The method and system that is used for dynamic motor braking |
| EP2433757A2 (en) * | 2010-09-28 | 2012-03-28 | Black & Decker Inc. | Method and system for electronic braking of a motor |
| JP2016158464A (en) * | 2015-02-26 | 2016-09-01 | ミネベア株式会社 | Brushless motor drive control device and drive control method |
| US20170234484A1 (en) * | 2016-02-12 | 2017-08-17 | Black & Decker Inc. | Electronic braking for a power tool having a brushless motor |
| US20180013360A1 (en) * | 2016-07-06 | 2018-01-11 | Black & Decker Inc. | Electronic braking of brushless dc motor in a power tool |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022099669A1 (en) * | 2020-11-16 | 2022-05-19 | 博世电动工具（中国）有限公司 | Electric tool and three-phase electric motor control device and method thereof |
| WO2022170548A1 (en) * | 2021-02-10 | 2022-08-18 | Techtronic Cordless Gp | Device and method for motor braking |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2019137865A1 (en) | 2019-07-18 |
| DE102018200513A1 (en) | 2019-07-18 |
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