DE102018114127A1 - guard - Google Patents

Abstract

The disclosure comprises a protective device (100) for overcurrent and overvoltage-protected energy transmission from a two-pole voltage connection (101) to an electrical consumer (103), with a first fuse circuit (105), which is designed when a first current limit value is reached by a line current of to prevent the voltage connection (101) to the electrical consumer (103) from flowing the line current, an overvoltage protection circuit (107) connected downstream of the first fuse circuit (105) and upstream of the electrical consumer (103), which is designed when a first voltage limit value is reached Voltage at the voltage connection (101) to connect the poles of the voltage connection (101) in an electrically conductive manner in order to force a line current which reaches the first current limit value and a second fuse circuit (109) which follows the overvoltage protection circuit (107) is connected and connected upstream of the electrical consumer (103), the second fuse circuit (109) being designed to prevent the line current from flowing when the line current reaches a second current limit, the second current limit being less than the first current limit.

Description

The present disclosure relates to a protective device for the overcurrent and overvoltage-protected transmission of electrical energy from a voltage connection to an electrical consumer.

Protective devices for limiting a current, a voltage and / or a power are usually used in isolating amplifiers in order to protect downstream electrical components from current, voltages and / or powers above a respectively predetermined limit value. Accordingly, the maximum rated data of electrical components which are connected downstream of the protective device can advantageously be reduced. With the protective device, an electrical consumer can also be safely disconnected from the voltage connection in order to meet explosion protection requirements.

The protective device typically has an overcurrent protection and an overvoltage protection connected downstream of the overcurrent protection. The overvoltage protection can short-circuit the voltage when a voltage limit value is reached, so that a short-circuit current flows through the overcurrent fuse, which can subsequently trip when a nominal current is reached in order to interrupt the current flow. In a disadvantageous manner, it may be necessary to dimension the downstream electrical components according to the nominal current and / or according to the voltage limit. Accordingly, the electrical components can have increased component dimensions and increased rated current levels and / or increased rated voltages that are not necessary for operation below the nominal current and / or voltage limit value.

It is the object of the present disclosure to provide a more efficient protective device which enables the protective device to be followed by electrical components which can be designed for lower maximum rated currents than is possible with conventional protective devices.

This object is solved by the features of the independent claim. Advantageous embodiments are the subject of the dependent claims, the description and the accompanying figures.

The present disclosure is based on the knowledge that the above object can be achieved by a protective device which, in addition to a first overcurrent fuse and an overvoltage limiter, has an additional overcurrent fuse. In particular, a first fuse can be connected downstream of a second fuse, which trips at a lower rated current than the first fuse. As a result, the electrical consumer can also be protected against overcurrents which are smaller than the short-circuit current caused by the overvoltage device. The first overvoltage limitation and the additional overcurrent protection can be a clamping circuit which can be triggered by two separate voltage limit switches, in particular differently dimensioned Z diodes.

According to a first aspect, the disclosure relates to a protective device for the overcurrent and overvoltage-protected transmission of electrical energy from a voltage connection to an electrical consumer, the voltage connection having two poles. The protective device comprises a first fuse circuit, which is designed to prevent the line current from flowing when the line current reaches a first nominal current from the voltage connection to the electrical consumer. Furthermore, the protective device comprises an overvoltage protection circuit which is connected downstream of the first fuse circuit and is connected upstream of the electrical consumer. The overvoltage protection circuit is designed to connect the poles of the voltage connection in an electrically low-resistance manner when a first voltage limit value of a voltage is reached at the voltage connection in order to force a line current which triggers the first rated current in order to trigger the first fuse circuit. Furthermore, the protective device comprises a second fuse circuit, which is connected downstream of the overvoltage protection circuit and upstream of the electrical consumer. The second fuse circuit is designed to prevent the line current from flowing when the line current reaches a second rated current. The second rated current depends on the electrical consumer.

In one embodiment, the second rated current is smaller than the first rated current in order to prevent a current flow with a correspondingly lower short-circuit current to the electrical consumer.

The protective device can be a combination of an overcurrent fuse and a clamping circuit (crowbar), with which an electrical consumer prevents the flow of an electric current with a current strength above a current strength permitted for the electrical load and / or the application of a voltage above one for the consumer permissible maximum voltage can be secured. In particular, in Combination of the limitation of the current strength and the voltage also defines a maximum electrical power that the consumer can implement.

Furthermore, the protective device can be arranged, for example, in a signal input of an isolation amplifier in order to be able to reduce the maximum rated data of downstream electrical components. Furthermore, the protective device can form an explosion protection in order to enable operation of the downstream electrical components in an explosive environment and / or atmospheres.

The protective device can be connected downstream of an energy feed of an electrical consumer in order to be able to expect predetermined current, voltage and / or power values after the protective device. Correspondingly, electronic circuits connected downstream of the protective device can have smaller air and / or creepage distances, since a reduced voltage and / or current level can be expected.

With the arrangement of a second fuse circuit after the first fuse circuit, the advantage can be achieved that the electrical parameters, in particular the maximum rated current, between electronic components which are connected downstream of the second fuse circuit can be set more flexibly. The second fuse circuit can be designed as a chip fuse, which has reduced component dimensions compared to the first fuse circuit. Furthermore, electrical components which are connected downstream of the second fuse circuit can have reduced component dimensions and / or reduced performance data compared to an arrangement after the first fuse circuit.

The voltage connection for the fuse circuit can in particular be formed by a circuit which is arranged between an energy supply network and the fuse circuit. This intermediate stage can be, for example, a switching power supply and / or a voltage converter.

The second rated current can be less than the first rated current. In particular, if a voltage transformation of the voltage of the voltage connection is not provided between the first fuse circuit and the second fuse circuit, electrical consumers connected downstream of the second fuse circuit can have lower nominal currents and can be produced correspondingly more cost-effectively and / or less.

Furthermore, a voltage transformer can be arranged between the first fuse circuit and the second fuse circuit, which is designed to increase or decrease the voltage of the voltage connection. The voltage transformer can, for example, be designed to reduce a voltage from 24 V to 5 V. Electrical consumers connected downstream of the second fuse circuit can be designed for a higher current intensity than the first fuse circuit, so that the second nominal current is greater than the first nominal current.

The protective device can be a back-up fuse which is connected downstream of an energy feed in order to provide current, voltage and / or power values to electrical consumers which are connected downstream of the protective device. Insulation distances between electrical components of an electrical consumer can in particular be adapted to a maximum voltage level, for example of 50 V. The protective device can be followed, for example, by a switched-mode power supply which increases or decreases the output voltage of the energy feed. In particular, a voltage in the range from 20 V to 30 V can be reduced to a voltage from 3 V to 12 V. A downstream isolating element, for example a transformer, can accordingly be dimensioned for lower maximum voltages than would be possible using a conventional crowbar circuit.

For example, the first fuse circuit can be designed to prevent the line current from flowing at a prospective short-circuit current of 1500 A, and the overvoltage protection circuit limits the voltage to an adjustable voltage value, for example 18 V. Accordingly, the second fuse circuit can be designed to flow a line current with a current strength below the short-circuit current protected by the first fuse circuit. Correspondingly, parameters for protecting downstream electronic circuits can be selected from a wide range of parameters, since the second fuse circuit can be designed as a chip fuse and can accordingly be produced in a large number of designs. In particular, such a protective device can be composed of electronic components that have a high availability on the market and can therefore be produced efficiently and inexpensively.

In one embodiment, the second nominal current, which is in particular a second prospective short-circuit current, is smaller than the first nominal current, which is in particular a first prospective short-circuit current, and / or wherein the Overvoltage protection circuit is designed to reduce a nominal voltage of the second fuse circuit. As a result, the aforementioned advantages are realized.

In one embodiment, the first fuse circuit and the second fuse circuit each have an overcurrent protection fuse, in particular a fuse and / or a circuit breaker, the overcurrent protection fuse being designed when the first rated current or the second rated current is reached, the electrical connection between the voltage connection and the electrical consumer to separate or to separate after a predetermined time interval after reaching the first rated current or the second rated current.

The predetermined time interval can be determined by a tripping delay of the respective fuse, in which a wire element of the fuse is heated and melted by the current flow. The tripping delay of the overcurrent protection fuse in the first protection circuit can be greater than the tripping delay of the overcurrent protection fuse in the second protection circuit. In particular, the first overcurrent protection fuse is used for the subsequent disconnection of the electrical connection between the voltage connection and the electrical consumer after the semiconductor switch has switched. A line current with a current above the first nominal current, which triggers the first overcurrent protection fuse, flows via the semiconductor switch and thus not to the electrical consumer.

The second overcurrent protection fuse can protect the electrical consumer from a line current with a current intensity that could damage the electrical consumer. The second overcurrent protection fuse can therefore trip faster and at a lower current than the first overcurrent protection fuse.

In one embodiment, the first protection circuit and / or the second protection circuit are designed to interrupt an electrical connection between the voltage connection and the electrical consumer when a short-circuit current flows through the overvoltage protection circuit, in order to ensure that the line current flows at a current strength above the first rated current and / or prevent above the second rated current to the electrical consumer.

The electrical connection can be interrupted by means of a blocking semiconductor element, a mechanical switching contact or by means of a defined melting of the overcurrent protection fuse. Accordingly, disconnection of the electrical connection can be carried out reversibly or, in the case of defined melting, can be carried out irreversibly. After the first protective circuit and / or the second protective circuit has been triggered, manual intervention may be necessary in order to put the circuit back into operation. For example, it may be necessary to replace one of the overcurrent protection fuses and / or to correct the cause of the overvoltage or overcurrent.

In one embodiment, the second fuse circuit has at least two current paths, which are each designed to transmit electrical energy to an electrical consumer, an overcurrent protection fuse being arranged in each of the current paths.

In one embodiment, the overcurrent protection fuses in the current paths are designed to trip at different nominal currents in order to prevent current flow in the respective current path.

In one embodiment, the first fuse circuit and / or the second fuse circuit are designed to detect a component and / or ambient temperature and to trigger the overvoltage protection circuit when the component and / or ambient temperature reaches a temperature limit and / or to cause a current to flow from the voltage connection to prevent the electrical consumer. This has the advantage that the electrical consumer can be protected against thermal loads.

In one embodiment, the second fuse circuit is designed to provide the electrical consumer with a reduced maximum electrical power compared to the composite consisting of the first fuse circuit and the overvoltage protection circuit by limiting the line current to the second nominal current.

In one embodiment, the overcurrent protection fuse can be connected downstream of the electrical consumer.

• 1 eine Schutzvorrichtung in einer Ausführungsform; und
• 2 eine Schutzvorrichtung in einer Ausführungsform.

Further exemplary embodiments are explained with reference to the attached figures. Show it:

• 1 a protection device in one embodiment; and
• 2 a protective device in one embodiment.

1 shows a schematic representation of the protective device 100 for overcurrent and overvoltage-protected transmission of electrical energy from a voltage connection 101 to an electrical consumer 103 , the voltage connection 101 has two poles. The protection device 100 comprises a first fuse circuit 105 , which is formed when a first rated current is reached by a line current from the voltage connection 101 to the electrical consumer 103 to prevent the line current from flowing.

The protective device also includes 100 an overvoltage protection circuit 107 which of the first fuse circuit 105 downstream and the electrical consumer 103 is connected upstream. The surge protection circuit 107 is formed when a first voltage limit value of a voltage is reached at the voltage connection 101 the poles of the voltage connection 101 electrically conductive to trigger the first fuse circuit 105 to force a line current that reaches the first rated current.

The protective device also includes 100 a second fuse circuit 109 which of the surge protection circuit 107 downstream and the electrical consumer 103 is connected upstream. The second fuse circuit 109 is designed to prevent the line current from flowing when the line current reaches a second nominal current. The second rated current is less than the first rated current.

The surge protection circuit 107 includes a semiconductor switch 111 , in particular a thyristor, which is electrically parallel with the poles of the voltage connection 101 is connected and a control input 113 having. The semiconductor switch 111 is designed with one at the control input 113 applied control signal the poles of the voltage connection 101 to be electrically conductive and if the line current falls below the minimum current value the electrical connection of the poles of the voltage connection 101 repealed.

Furthermore, the overvoltage device comprises 107 a voltage limit switch 115 , in particular a zener diode with a switch input 117 and a switch output 119 , The voltage limit switch 115 is via the switch input 117 the first fuse circuit 105 downstream and via the switch output 119 with the control input 113 of the semiconductor switch 111 connected. Furthermore, the voltage limit switch 115 formed when the first voltage limit value is reached by the voltage at the voltage connection 101 at the switch output 119 to provide the control signal.

The surge protection circuit 107 also includes a resistor 121 which is the switch output 119 of the voltage limit switch 115 is connected downstream and with the voltage limit switch 115 electrically parallel to the poles of the voltage connection 101 is arranged. The control input 113 is with the switch output 119 of the voltage limit switch 115 and the resistance 121 connected, the resistance 121 is formed when switching the voltage limit switch 115 at the control input 113 a control signal, in particular in the form of part of the voltage at the voltage connection 101 to provide to the semiconductor switch 111 to switch.

The first fuse circuit 105 and the second fuse circuit 109 each have an overcurrent protection fuse 123 . 125 , in particular a fuse. The overcurrent protection fuse 123 is designed, when the first current limit value is reached, the electrical connection between the voltage connection 101 and the electrical consumer 103 to separate or to separate after a predetermined time interval after reaching the first rated current. The overcurrent protection is corresponding 125 formed, when the second rated current is reached, the electrical connection between the voltage connection 101 and the electrical consumer 103 to separate or to separate after a predetermined time interval after reaching the second current limit.

2 shows a schematic representation of the protective device 100 for the transmission of electrical energy from a voltage connection 101 to at least two electrical consumers 103 . 205 , The protection device 100 comprises a first fuse circuit 105 , which is formed when a first rated current is reached by a line current from the voltage connection 101 to electrical consumers 103 . 205 to prevent the line current from flowing.

The protective device also includes 100 an overvoltage protection circuit 107 which of the first fuse circuit 105 downstream and the electrical consumers 103 . 205 is connected upstream. The surge protection circuit 107 is formed when a first voltage limit value of a voltage is reached at the voltage connection 101 the poles of the voltage connection 101 electrically conductive to trigger the first fuse circuit 105 force a line current that reaches the first rated current.

The protective device also includes 100 a second fuse circuit 109 which of the surge protection circuit 107 downstream and the electrical consumers 103 . 205 is connected upstream. The second fuse circuit 109 has two current paths 201-1 . 201-2 on, which are each formed electrical energy to an electrical consumer 103 . 205 transferred to. In the current paths 201-1 . 201-2 is an overcurrent protection fuse 125 . 203 arranged.

The overcurrent protection fuse 125 is designed when a second nominal current of a current flow through the current path is reached 201-1 a flow of current through the current path 201-1 to prevent. The overcurrent protection fuses 203 is designed when a third nominal current of a current flow through the current path is reached 201-2 a flow of current through the current path 201-2 to prevent. The second nominal current and the third nominal current can each be smaller than the first nominal current. The overcurrent protection fuses 125 . 203 are designed to trigger at different nominal currents in order to flow a current in the respective current path 201-1 . 201-2 to prevent.

LIST OF REFERENCE NUMBERS

100

guard

101

voltage connection

103

Electrical consumer

105

First fuse circuit

107

Overvoltage protection circuit

109

Second fuse circuit

111

Semiconductor switches

113

control input

115

Voltage limit switch

117

switch input

119

switch output

121

resistance

123

Overcurrent protection fuse

125

Overcurrent protection fuse

201-1

Current path

201-2

Current path

203

Overcurrent protection fuse

205

Electrical consumer

Claims (10)

Protection device (100) for the overcurrent and overvoltage-protected transmission of electrical energy from a voltage connection (101) to an electrical consumer (103), the voltage connection (101) having two poles, with: a first fuse circuit (105) which is designed to prevent the line current from flowing when the line current from the voltage connection (101) to the electrical consumer (103) reaches a first rated current; an overvoltage protection circuit (107), which is connected downstream of the first fuse circuit (105) and is connected upstream of the electrical consumer (103), the overvoltage protection circuit (107) being designed, when a first voltage limit value of a voltage at the voltage connection (101) is reached, the poles of the voltage connection (101) electrically conductive to force a line current to reach the first rated circuit to trip the first fuse circuit (105); and a second fuse circuit (109) which is connected downstream of the overvoltage protection circuit (107) and is connected upstream of the electrical consumer (103), the second fuse circuit (109) being designed to prevent the line current from flowing when the line current reaches a second rated current, whereby the second rated current depends on the electrical consumer (103). Protection device (100) after Claim 1 , wherein the second nominal current, which is in particular a second prospective short-circuit current, is smaller than the first nominal current, which is in particular a first prospective short-circuit current, and / or wherein the overvoltage protection circuit (107) is designed, a nominal voltage of the second fuse circuit (109) reduce. Protective device (100) according to one of the preceding claims, wherein the second rated current is smaller than the first rated current in order to prevent a current flow with a correspondingly lower short-circuit current to the electrical consumer (103). Protection device (100) according to one of the preceding claims, wherein the overvoltage protection circuit (107) comprises a semiconductor switch (111) which is electrically connected in parallel to the poles of the voltage connection (101) and has a control input (113), the Semiconductor switch (111) is designed to connect the poles of the voltage connection (101) in an electrically conductive manner with a control signal applied to the control input (113) and to drop the electrical connection of the poles of the voltage connection (101) when the line current falls below the minimum current value. Protection device (100) after Claim 4 , wherein the semiconductor switch (111) is formed by a thyristor or by a transistor. Protection device (100) according to one of the preceding claims, wherein the first fuse circuit (105) and the second fuse circuit (109) each have an overcurrent protection fuse (123, 125), in particular a fuse and / or a circuit breaker, and wherein the respective overcurrent protection fuse (123 , 125) is designed to disconnect the electrical connection between the voltage connection (101) and the electrical consumer (103) when the first current limit value or the second rated current is reached, or after a predetermined time interval has elapsed after the first rated current or the second rated current has been reached separate. Protection device (100) according to one of the preceding claims, wherein the second fuse circuit (109) has at least two current paths (201-1, 201-2), which are each designed to transmit electrical energy to an electrical consumer (103, 205), wherein An overcurrent protection fuse (125, 203) is arranged in each of the current paths (201-1, 201-2). Protection device (100) after Claim 7 , wherein the overcurrent protection fuses (125, 203) are designed to trip at different nominal currents in order to prevent current flow in the respective current path (201-1, 201-2). Protection device (100) according to any one of the preceding claims, wherein the first fuse circuit (105) and / or the second fuse circuit (109) are designed to detect a component and / or ambient temperature and when a temperature limit value is reached by the component and / or Ambient temperature to trigger the overvoltage protection circuit (107) and / or to prevent a current from flowing from the voltage connection (101) to the electrical consumer (103). Protective device (100) according to any one of the preceding claims, wherein the second fuse circuit (109) is formed, the electrical consumer (103) compared to the composite consisting of the first fuse circuit (105) and the overvoltage protection circuit (107) by means of a limitation of the line current to provide the second rated current with a reduced maximum electrical power.

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