CN116724373A - Protection switching device and method - Google Patents
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- CN116724373A CN116724373A CN202180085748.4A CN202180085748A CN116724373A CN 116724373 A CN116724373 A CN 116724373A CN 202180085748 A CN202180085748 A CN 202180085748A CN 116724373 A CN116724373 A CN 116724373A
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Abstract
The invention relates to a protection switching device (for a low-voltage circuit) having a mechanical breaking contact unit MK, which is connected in series with an electronic breaking unit EU, which can be switched by opening the contact to prevent the flow of current in the low-voltage circuit or closing the contact for the flow of current in the low-voltage circuit; the electronic interrupt unit EU can be switched to a high-ohmic state of the switching element by the semiconductor-based switching element to prevent a current flow in the low-voltage circuit or to a low-ohmic state of the switching element for a current flow of the low-voltage circuit; determining the magnitude of the current of the circuit so that an instantaneous current value exists; initiating a blocking of current flow to the low voltage circuit when the magnitude of the instantaneous current value exceeds at least one current threshold; at least one current threshold is adjusted as a function of the temperature level of the protection switching device.
Description
Technical Field
The invention relates to the technical field of protection switching devices for low-voltage circuits with electronic interrupt units and to a method for protection switching devices for low-voltage circuits with electronic interrupt units.
Background
Low voltage refers to voltages up to an ac voltage of 1000 volts or up to a dc voltage of 1500 volts. The low voltage is in particular a voltage which is greater than a low voltage having a value of an alternating voltage of 50 volts or a direct voltage of 120 volts.
A low voltage circuit or low voltage network or low voltage device refers to a circuit having a nominal current or rated current of up to 125 amps, more specifically up to 63 amps. A low-voltage circuit particularly means a circuit with a nominal current or rated current of up to 50 amperes, 40 amperes, 32 amperes, 25 amperes, 16 amperes or 10 amperes. The current values mentioned are in particular indicative of the nominal current, the rated current or/and the off current, i.e. the maximum current that is normally conducted through the circuit, or at these currents the circuit is usually interrupted, for example by a protection device such as a protection switching device, a line protection switch or a circuit breaker.
Line protection switches are overcurrent protection devices for use in low-voltage circuits in electrical installation technology, which have long been known. The line protection switch protects the line from damage due to heat generated by an excessively large circuit and/or a short circuit. The line protection switch may automatically open the circuit in case of overload and/or short circuit. The line protection switch is a safety element which cannot be reset automatically. Unlike line protection switches, circuit breakers are set for currents greater than 125A, some of which have also been from 63 amps. Thus, the line protection switch is constructed in a simpler and more elaborate manner. Line protection switches generally have a fastening possibility for fastening to so-called top hat rails (support rails, DIN rails, TH 35).
The line protection switch is constructed electromechanically. It has a mechanical switch contact or operating current trigger in the housing for interrupting (opening) the current. In general, in the case of an overcurrent which lasts for a longer time (overcurrent protection) or in the case of a thermal overload (overload protection), a bimetal protection element or a bimetal element is used for the disconnection (interruption). When the overcurrent limit value is exceeded or in the event of a short circuit (short-circuit protection), an electromagnetic trigger with a coil is used for short-time disconnection. One or more extinguishing chambers or means for extinguishing an arc are provided. Furthermore, a connection element of the conductor of the circuit to be protected is provided.
Protection switching devices with electronic interrupt units are relatively new developments. Which has a semiconductor-based electronic interrupt unit. That is, the current flow of the low-voltage circuit is led through a semiconductor member or a semiconductor switch capable of interrupting the current flow or switching to be conductive. Furthermore, protection switching devices with electronic breaking units often have a mechanical breaking contact system, in particular a mechanical breaking contact system according to the breaker characteristics of the relevant standard for low-voltage circuits, wherein the contacts of the mechanical breaking contact system are connected in series with the electronic breaking unit, i.e. the current of the low-voltage circuit to be protected is conducted not only through the mechanical breaking contact system but also through the electronic breaking unit.
In the case of semiconductor-based protection switching devices or protection devices, which are referred to in modern german as Solid State Circuit Breaker (solid state circuit breakers, abbreviated to SSCB), the switching energy is not converted into an arc as in the case of mechanical switching devices, but rather has to be converted into heat by means of an additional switching circuit, i.e. an energy absorber. The shut-off energy here comprises the energy stored in the circuit, i.e. in the network impedance, the line impedance or the load impedance (consumer impedance). In order to reduce the load on the energy absorber, the current flowing at the moment of switching off must be as small as possible. This also applies in the case of a short circuit. Here, the current increases very rapidly. By means of the rapid short-circuit detection, a short-circuit can be detected early and excessive short-circuit currents can be avoided. The semiconductor-based protection switching device interrupts the circuit with little delay in the sense of a shut-down process within a few mus. No large currents occur and the load on the energy absorber of the semiconductor-based protection switching device is reduced. Known short circuit identification or shutdown criteria are typically based on the determination and evaluation of the actual current value.
The invention relates to a low-voltage alternating current circuit having an alternating voltage, typically having a sinusoidal alternating voltage with respect to time, the alternating voltage having a frequency f, typically 50 or 60 hertz (Hz). The time dependence of the instantaneous voltage value u (t) of the alternating voltage is described by the following equation:
u(t)＝U＊sin(2Π＊f＊t)。
wherein:
u (t) =instantaneous voltage value with respect to time t
U=amplitude of voltage (maximum value)
The harmonic alternating voltage can be represented by the rotation of a pointer (Zeiger), the length of which corresponds to the amplitude (U) of the voltage. Here, the instantaneous deflection is the projection of the pointer onto the coordinate system. One oscillation period corresponds to one complete rotation of the pointer, with a complete angle of 2Pi (2 Pi) or 360 °. The angular frequency is the rate of change of the phase angle of this rotating pointer. The angular frequency of the harmonic oscillation is always 2pi times the frequency thereof, namely:
ω=2pi×f=2pi/t=angular frequency of ac voltage (t=cycle time of oscillation)
The presentation of the angular frequency (ω) is often preferred over the frequency (f) because many formulas of the oscillation theory can be represented more compactly by means of the angular frequency due to the occurrence of trigonometric functions according to a defined period of 2pi:
u(t)＝U＊sin(ωt)
in case the angular frequency is not constant in time, the term instantaneous angular frequency is also used.
In the case of sinusoidal, in particular temporally constant, ac voltagesThe time-dependent value of the angular velocity ω and the time t corresponds to the time-dependent angleIt is also called phase angle->I.e. phase anglePeriodically through a range of 0 … pi or 0 deg. … deg.. That is, the phase angle periodically takes a value between 0 and 2pi or 0 and 360 ° (due to periodicity, -)>Or->The abbreviation is: />Or alternatively)。
The instantaneous voltage value u (t) thus refers to the instantaneous value of the voltage at the point in time t, i.e. in the case of sinusoidal (periodic) alternating voltages, to the phase angleThe value of the voltage at (corresponding period +.>Or alternatively)。
Disclosure of Invention
The object of the present invention is to improve a protective switching device of the type mentioned at the beginning, in particular to clarify the possibility that an electronic interruption unit reliably prevents a current flow in the event of a short circuit or an overcurrent, i.e. in the event of at least one current threshold being exceeded.
The above-mentioned technical problem is solved by a protection switching device having the features of claim 1 and by a method according to claim 19.
According to the invention, there is provided an (electronic) protection switching device for protecting a low-voltage circuit, in particular a low-voltage alternating-current circuit, the protection switching device having:
A housing having a first connection, in particular a network-side connection, and a second connection, in particular a load-side connection, for a conductor of a low-voltage alternating current circuit,
a mechanical breaking contact unit connected in series with the electronic interruption unit,
wherein, in particular, the mechanical breaking contact unit is assigned to the (second) load-side connection and the electronic breaking unit is assigned to the (first) grid-side connection,
the mechanical breaking contact unit is capable of switching by opening the contacts to prevent current flow in the low voltage circuit or closing the contacts for current flow in the low voltage circuit,
the electronic interruption unit is switchable by means of a semiconductor-based switching element to a high-ohmic state of the switching element for preventing a current flow in said low-voltage circuit or to a low-ohmic state of the switching element for a current flow of the low-voltage circuit,
a current sensor unit for determining the magnitude of the current of the low-voltage circuit such that an instantaneous current value is present,
a control unit connected to the current sensor unit, the mechanical breaking contact unit and the electronic breaking unit, wherein upon exceeding at least one current threshold value, a blocking of the current flow of the electrical circuit is initiated,
The protective switching device is designed such that,
at least one current threshold is adjusted as a function of the temperature level of the protection switching device.
This has the particular advantage that, in the event of an overcurrent or short circuit, the protection switching device can be reliably prevented, i.e. can be switched off, in particular by the electronic interrupt unit. Here, "reliable" in this context means that the semiconductor-based switching element (e.g. the power semiconductor) is protected from damage due to heat. The switching power of the electronic interrupt unit, in particular of its (power) semiconductors, is limited by the (current) operating temperature, in particular by the heat which occurs at high currents, in particular in the event of short circuits, and which can lead to thermal overload. In order to achieve reliable switching-off without excessively sizing the electronic interrupt unit, in particular its (power) semiconductor (when at least one current threshold is exceeded), the size of the at least one current threshold is adjusted as a function of the temperature level of the protection switching device, in particular of the particular unit of the protection switching device. Therefore, according to the present invention, high efficiency and high economic efficiency can be achieved with a simple unit.
Advantageous embodiments of the invention are given in the dependent claims.
In an advantageous embodiment of the invention, the protection switching device is designed to set the at least one current threshold value as a function of the temperature level in such a way that the at least one current threshold value decreases when the temperature increases and increases, in particular to a maximum value of the at least one current threshold value, when the temperature decreases.
The current threshold is therefore advantageously reduced at high temperatures in order to make full use of the current carrying capacity or heat capacity of, in particular, the electronic interrupt unit, more particularly its (power) semiconductor.
In an advantageous embodiment of the invention, the protection switching device is designed such that the temperature level of the protection switching device is the temperature level inside the housing in the protection switching device.
This has the particular advantage that a simple design is provided, since the protective switching device is generally compact and conclusions can be drawn about the temperature of the units located therein from the temperature level in the protective switching device, i.e. in the environment enclosed by the housing.
In an advantageous embodiment of the invention, the protection switching device is designed such that the temperature level of the protection switching device is the temperature level of the electronic interrupt unit.
This has the particular advantage that, in particular, the heat capacity of the electronic interrupt unit, for example, for which a main shut-off process (current flow prevention) is to be performed, can be maximally utilized.
In an advantageous embodiment of the invention, the protection switching device is designed such that the temperature level of the protection switching device is the temperature level of the (power) semiconductor of the electronic interrupt unit.
This has the particular advantage that, in particular, the heat capacity of the (power) semiconductor, which conducts the current, can be used to a maximum extent, which avoids excessively large dimensioning and ensures a high economic utilization.
In an advantageous embodiment of the invention, at least one temperature sensor unit is provided in the protection switching device, which temperature sensor unit is connected to the control unit for determining the temperature level.
This has the particular advantage that a simple temperature determination method is provided.
In an advantageous embodiment of the invention, the protection switching device is designed to determine or calculate the temperature level from the measured current.
This has the particular advantage that a replacement possibility for determining the temperature level without using a temperature sensor unit is given. The temperature level in the protection switching device is mainly determined by the magnitude of the current flowing through the low-voltage circuit of the protection switching device. Thus, a simple "low cost" variant can be achieved.
In an advantageous embodiment of the invention, the protection switching device is designed to determine the temperature level from the measured current magnitude in such a way that the calculation takes into account the current magnitude using the electrical model and the thermal model.
In an advantageous embodiment of the invention, the protection switching device is designed in such a way that the temperature level is determined from the temperature sensor contained in the device and its determined temperature level and the magnitude of the measured current, i.e. the magnitude of the instantaneous value of the current is taken into account by means of an electrical model and a thermal model, to calculate.
In an advantageous embodiment of the invention, the protection switching device is designed to continuously adjust at least one current limit value. Furthermore, in particular an adjustment can be performed faster than 20ms, more particularly faster than 10ms or preferably faster than 1 ms.
This has the particular advantage that the current threshold value is used together quickly to achieve maximum utilization of the electronic interrupt unit, in particular of its (power) semiconductor, and thus to achieve high economic utilization.
In an advantageous embodiment of the invention, the protection switching device is designed to compare the instantaneous current value of the determined magnitude of the current with at least one current threshold value by means of an analog comparator, so that a blocking of the current flow of the low-voltage circuit is initiated if the magnitude of the current exceeds the magnitude of the at least one current threshold value.
Reasonably in this context, "the magnitude of the current exceeds the magnitude of the at least one current threshold" means that the current threshold is exceeded in the case of a positive current value and is below a negative (identical in magnitude) current threshold (alternating current) in the case of a negative current value. This can also be achieved by a comparison in terms of magnitude.
This has the particular advantage that a rapid blocking (switching off) of the current flow is achieved, in particular by means of the electronic interrupt unit.
In an advantageous embodiment of the invention, the protection switching device is designed such that the protection switching device is designed to digitally calculate (by the control unit or, for example, by a microprocessor or microcontroller contained therein) at least one current threshold value, to convert the calculated digital current threshold value into an analog current threshold value using a digital-to-analog converter,
the analog current threshold is fed to a comparator.
This has the particular advantage of combining the processing speed of analog circuits (typically in the range of a few nanoseconds ns, for example 5-10 ns) with the flexibility of a digitally programmable intelligent system (e.g. microprocessor/microcontroller).
The analog comparator operates in a continuous manner over time, i.e. not in a discrete manner over time. Thereby, an overcurrent (exceeding a current threshold) can be identified in a very short time. The microprocessor/microcontroller operates as a discrete controller over time, so the response time is limited to processing beats, typically in the range of 10-100 mus.
With this combination, flexibility and adjustability of the digital (instantaneous) current threshold can be maintained while achieving high response times of the analog circuit. This is possible because the adjustment of the current threshold does not need to take place in the nanosecond/ns range, only its comparison with the (current) instantaneous value of the current value should be performed in the ns range, which can be achieved by this arrangement/combination.
In an advantageous embodiment of the invention, the protection switching device is designed to convert the temperature level into a digital temperature value, multiply the digital temperature value by a certain factor, and subtract the resulting product from at least one current threshold value to obtain the adjusted current limit value.
This has the particular advantage that a particularly simple calculation or adjustment of the current threshold value as a function of the temperature level is provided.
In an advantageous embodiment of the invention, the protection switching device is designed to convert the temperature level into a digital temperature value, to reduce the digital temperature value by a certain correction value, and to subtract the result from at least one current limit value in order to obtain the adjusted current limit value.
This has the particular advantage that a further particularly simple calculation or adjustment of the current threshold value as a function of the temperature level is provided.
In an advantageous embodiment of the invention, a voltage sensor unit is provided for determining the magnitude of the voltage of the low-voltage circuit, so that an instantaneous voltage value is present.
Furthermore, there is a (periodic) temporal curve of the magnitude of the voltage, i.e. a (periodic) instantaneous current threshold value which is related to the instantaneous voltage value.
The instantaneous current value is compared to an instantaneous current threshold in a phase-dependent manner. When the instantaneous current threshold is exceeded (in magnitude), an interruption of the low voltage circuit is initiated.
This has the particular advantage that a threshold value/current threshold value is present which is dependent on the periodicity of the voltage, in order to achieve a rapid current flow prevention (triggering), in particular by means of the electronic interrupt unit. In the case of small voltages, a small current threshold is used, and in the case of large voltages, a large current threshold is used.
In an advantageous embodiment of the invention, the (periodic) instantaneous current threshold has a minimum value that is greater than zero. In particular, the minimum value is greater than 5, 10, 15 or 20%. More specifically, in particular in the range of 5 to 20% of the maximum value, i.e. the maximum current threshold.
This has the particular advantage that a short-circuit current can be detected reliably and quickly at a low current threshold or low voltage, and false triggering is avoided.
In an advantageous embodiment of the invention, the voltage circuit has a voltage profile that is sinusoidal over time (ideal). In particular, the low voltage circuit is a low voltage ac circuit. The instantaneous current threshold likewise has a current curve that is (almost) sinusoidal in time, in particular in terms of magnitude. In particular, the zero crossing or the region of the zero crossing has a minimum value (in terms of magnitude) which is greater than zero, in particular greater than 5, 10, 15 or 20%, in particular in the range of the maximum value, i.e. 5 to 20% of the maximum current threshold value. The curves of the voltage and current thresholds over time are synchronized in a phase-dependent manner such that the point in time of the amplitude of the voltage (maximum) coincides with the point in time of the amplitude of the current threshold (maximum).
This has the particular advantage that a simple identification is possible, in particular in the case of sinusoidal voltage curves.
In particular, the region of the zero crossing point of the voltage coincides with the region of the minimum value of the current threshold.
In an advantageous embodiment of the invention, the protection switching device is designed such that the control unit has an analog first subunit and a digital second subunit. The first subunit has a (analog) current comparator to which the instantaneous current value and the instantaneous current threshold are fed, in particular from the second subunit. The second subunit provides a current threshold in a phase-dependent manner according to a plot of voltage over time. Thereby, a phase-dependent comparison of the instantaneous current value with the instantaneous current threshold is enabled for a curve of the voltage over time. This enables an interruption of the low-voltage circuit to be initiated when a (momentary) current threshold is exceeded.
This has the particular advantage that the technical solution is simple to implement.
In an advantageous embodiment of the invention, the protection switching device is designed to be provided with a grid synchronization unit. The grid synchronization unit determines at least one phase angle of the voltage from the fed instantaneous voltage valueAlternatively, the amplitude (U) of the voltage is determined. A threshold unit is provided, which is connected to the grid synchronization unit in order to utilize the phase angle of the voltage +. >Amplitude of voltage (U) and maximum limit value/threshold value of current threshold value, =>To determine an instantaneous current threshold. The instantaneous current value is compared to an instantaneous current threshold in a phase-dependent manner to determine initiation (or start-up) of the prevention (interruption) of the current flow.
This has the particular advantage that the technical solution is further simple to implement.
Advantageously, the blocking of the current flow is initiated mainly by the electronic interruption unit. Additionally, or in the presence of other criteria, the current interruption may be initiated by a mechanical breaking contact system.
According to the invention, a corresponding method for protecting a switching device for a low-voltage circuit is claimed, the protective switching device having an electronic (semiconductor-based) switching element, which method has the same advantages as well as others.
In a method for protecting a low-voltage circuit with a protection switching device having a mechanical breaking contact unit, the mechanical breaking contact unit being connected in series with an electronic interruption unit,
wherein the mechanical breaking contact unit is capable of switching by opening the contacts to prevent current flow in said low voltage circuit or closing the contacts for current flow in the low voltage circuit,
Wherein the electronic interrupt unit is switchable, by means of a semiconductor-based switching element, to a high-ohmic state of the switching element for preventing a current flow in said low-voltage circuit or to a low-ohmic state of the switching element for a current flow in the low-voltage circuit,
wherein the magnitude of the current of the low voltage circuit is determined such that there is an instantaneous current value,
wherein blocking of the current flow of the low-voltage circuit is initiated when the magnitude of the instantaneous current value exceeds at least one current threshold,
at least one current threshold is adjusted as a function of the temperature level of the protection switching device.
In an advantageous embodiment of the invention, the at least one current threshold is set as a function of the temperature level in such a way that, when the temperature increases, the at least one current threshold is reduced and, when the temperature decreases, the at least one current threshold is increased, in particular to a maximum value of the at least one current threshold.
According to the invention, a corresponding computer program product is claimed. The computer program product comprises instructions which, when the program is executed by the microcontroller (=microprocessor), cause the microcontroller to improve the reliability of such a protection switching device or to achieve a higher reliability in a low-voltage circuit to be protected by the protection switching device, in particular the blocking of the flow of current by the electronic interrupt unit being reliably performed. The microcontroller (=microprocessor) is part of a protection switching device, in particular a control unit.
According to the invention, a corresponding computer-readable storage medium, on which the computer program product is stored, is claimed.
According to the invention, a data carrier signal is claimed, which transmits the computer program product.
All the solutions not only referring to claims 1 and 19 in a dependent manner, but also to the individual features or feature combinations of the claims, allow an improvement of the protection switching device for a fast and reliable switching off in the event of an overcurrent and a short circuit, and for avoiding thermal damage of the semiconductor-based switching element used in the event of an overcurrent and a short circuit.
Drawings
The described features, characteristics and advantages of the present invention, as well as the manner of attaining them, will become more apparent and the embodiments will be better understood in conjunction with the following description of embodiments, taken in conjunction with the accompanying drawings.
Here, in the drawings:
figure 1 shows a first illustration of a protection switching device,
figure 2 shows a second illustration of a protection switching device,
figure 3 shows a first design of a protection switching device,
figure 4 shows a second design of the protection switching device,
figure 5 shows a current threshold curve with respect to temperature,
Fig. 6 shows voltage and current threshold curves with respect to time.
Detailed Description
Fig. 1 shows a schematic representation of a protection switching device SG for protecting a low-voltage circuit, in particular a low-voltage ac circuit, having a housing GEH, the protection switching device SG having:
the connection for the conductors of the low-voltage circuit, in particular the first connection L1, N2 for protecting the connection EQ on the mains side, in particular on the energy source side, of the switching device SG, and the second connection L2, N2 for protecting the connection ES (connection on the consumer side) on the load side, in particular on the energy sink side (in the case of passive loads), of the switching device SG, wherein in particular the connection L1, L2 on the phase conductor side and the connection N2, N2 on the neutral conductor side can be provided;
the connection on the load side can have a passive load (consumer) or/and an active load ((additional) energy source) or can be a passive and active load, for example in time sequence;
a voltage sensor unit SU for determining the magnitude of the voltage of the low-voltage circuit so that there is an instantaneous voltage value (phase-dependent voltage value) DU,
a current sensor unit SI for determining the magnitude of the current of the low-voltage circuit, so that there is an instantaneous (phase angle dependent) current value DI,
An electronic interruption unit EU having a high-ohmic state of the switching element for blocking (in particular interrupting) and a low-ohmic state of the switching element for flowing a current in the low-voltage circuit due to the semiconductor-based switching element,
a mechanical breaking contact unit MK which can be switched by opening contacts to prevent a current flow in the low-voltage circuit or closing contacts for a current flow in the low-voltage circuit,
a control unit SE connected to voltage sensor unit SU, current sensor unit SI, mechanical breaking contact unit MK and electronic breaking unit EU.
The mechanical breaking contact unit MK is electrically connected in series with the electronic breaking unit EU.
The control unit SE may:
* Implemented with digital circuitry, for example with a microprocessor; the microprocessor may also contain an analog portion;
* Implemented with digital circuitry having analog circuitry portions.
The protection switching device SG, in particular the control unit SE, is designed to initiate a blocking of the current flow of the low-voltage circuit if at least one current threshold value is exceeded, in particular in a first step by the electronic interrupt unit EU.
That is, when at least one current threshold value, which is generally caused by a short circuit, in particular, a short circuit on the load side (ES), is exceeded, the electronic interruption unit EU is switched from a low-ohmic state to a high-ohmic state to interrupt the low-voltage circuit.
The protection switching device is designed to adjust at least one threshold value as a function of the temperature level of the protection switching device.
That is, at least one current threshold is set, and upon exceeding the at least one threshold in magnitude, a blocking of the current flow of the low voltage circuit is initiated. The one current threshold is then adjusted in accordance with the temperature level. Thus, a simple solution will be presented for the present invention.
A plurality of current thresholds may also be set, in particular instantaneous/phase angle dependent current thresholds may be set, so that an instantaneous or phase angle dependent comparison is performed depending on the phase angle of the voltage or current. The instantaneous or phase angle dependent current threshold may then be adjusted depending on the temperature level. In particular in low-voltage ac circuits, it is then possible to rapidly provide an adjusted instantaneous or phase angle-dependent current threshold value, for example for the following half-wave (or a set of adjusted current thresholds for each half-wave—in low-voltage ac circuits with a grid frequency of 50Hz, every 10 ms).
The comparison may be made such that there is a (periodic) instantaneous current threshold associated with a (periodic) time-dependent curve of the voltage or the magnitude of the determined instantaneous voltage value.
The instantaneous current threshold may exist in a continuous manner or in a phase angle manner.
The instantaneous current threshold may be present here for each individual phase angle, for a phase angle range (a plurality of phase angles), for example, every 2 ° or for a phase angle segment (a part of a phase angle), for example, every 0.5 ° or 0.1 °. In particular, a resolution of 1 ° to 5 ° (which corresponds to a sampling rate of 3.5 to 20 kHz) is particularly advantageous.
The instantaneous current value is compared to an instantaneous current threshold in a phase-dependent manner. When the instantaneous current threshold is exceeded in terms of magnitude, an interruption of the low-voltage circuit is initiated, for example, by a first interruption signal TRIP from the control unit SE to the electronic interruption unit EU, as is depicted in fig. 1.
According to fig. 1, an electronic interrupt unit EU is drawn as a module in both conductors. In the first variant, it is therefore meant that neither conductor is interrupted. At least one conductor, in particular the active conductor or the phase conductor, has a semiconductor-based switching element. The neutral conductor may be devoid of switching elements, i.e. devoid of semiconductor-based switching elements. I.e. the neutral conductor is directly connected, i.e. not high ohmic. I.e. only monopolar interruption (of the phase conductor) is performed. In a second variant of the electronic interruption unit EU, the phase conductors have semiconductor-based switching elements if further active conductors are provided. The neutral conductor is directly connected, i.e. does not become high ohmic. For example for a three-phase ac circuit.
In a third variant of the electronic interruption unit EU, the neutral conductor can likewise have a semiconductor-based switching element, i.e. both conductors become high-ohmic when the electronic interruption unit EU is interrupted.
The electron interruption unit EU may have a semiconductor member such as a bipolar transistor, a Field Effect Transistor (FET), an Insulated Gate Bipolar Transistor (IGBT), a metal oxide layer field effect transistor (MOSFET), or other (self-conducting) power semiconductor. In particular, IGBTs and MOSFETs are particularly suitable for use in the protection switching device according to the invention due to low on-resistance, high junction resistance and good switching characteristics.
The protective switching device SG can preferably have a mechanical breaking contact system MK according to the standard with a standard breaking characteristic for the current breaking of the electrical circuit, in particular for standard circuit activation (as opposed to switching off). The mechanical breaking contact system MK is connected to a control unit SE, as is depicted in fig. 1, so that the control unit SE can initiate a current breaking of the circuit.
In particular, a further evaluation can be achieved, which causes a current break when other criteria are met. For example, an overcurrent detection may be provided, for example in the control unit SE, which enables a semiconductor-based interruption or/and a current interruption of the circuit when an overcurrent occurs, i.e. when a current exceeding a current-time limit value is present for a certain time, i.e. for example when a certain energy threshold value is exceeded.
Alternatively or additionally, a current break may also be initiated, for example, when a short circuit is identified.
The initiation of the current interruption of the low-voltage circuit is effected, for example, by a further second interrupt signal TRIPG, which is sent from the control unit SE to the mechanical breaking contact system MK, as is depicted in fig. 1.
In a first variant, the mechanical breaking contact system MK can be interrupted in a monopolar manner. I.e. only one of the two conductors, in particular the active conductor or the phase conductor, is interrupted, i.e. it has mechanical contacts. The neutral conductor is then free of contacts, i.e. the neutral conductor is directly connected.
If additional active conductors/phase conductors are provided, in a second variant the phase conductors have mechanical contacts of a mechanical breaking contact system. In this second variant, the neutral conductor is directly connected. For example for a three-phase ac circuit.
In a third variant of the mechanical breaking contact system, the neutral conductor likewise has a mechanical contact, as is depicted in fig. 1.
The mechanical breaking contact system MK refers in particular to the (standard-compliant) breaking function achieved by the breaking contact system MK. The breaking function is as follows:
According to a standard minimum air gap (minimum distance of contacts),
contact position display of contacts of the mechanical breaking contact system,
opening of the mechanical breaking contact system is always possible (breaking contact system is not prevented by the handle).
The minimum air gap is essentially voltage dependent in terms of the minimum air gap between the contacts of the breaking contact system. Other parameters are the degree of pollution, the type of field (uniform, non-uniform) and the air pressure or altitude.
For these minimum air gaps or creepage paths, there are corresponding regulations or standards. In the case of air for surge voltage strengths, for example, these regulations give a minimum air gap for non-uniform as well as uniform (ideal) electric fields, depending on the degree of pollution. The surge voltage intensity is the intensity when the corresponding surge voltage is applied. Only when this minimum length (minimum gap) is present, the breaking contact system or the protective switching device has a breaking function (breaker characteristic).
In the sense of the present invention, DIN EN 60947 or IEC 60947 standards series, which are incorporated herein by reference, are relevant for the breaker function and its characteristics.
The breaking contact system is advantageously characterized by a minimum air gap of the breaking contact in the open position (open position, open contact) depending on the rated surge voltage strength and the pollution level. The minimum air gap is in particular between (minimum) 0.01mm and 14 mm. In particular, the minimum air gap is advantageously between 0.01mm at 0.33kV and 14mm at 12kV, in particular for a pollution level of 1, and in particular for non-uniform fields.
Advantageously, the minimum air gap may have the following values:
E DIN EN 60947-1(VDE 0660-100):2018-06
TABLE 13 minimum air gap
The contamination level and field type correspond to those defined in the standard. In this way, a standard-compliant protection switching device can advantageously be obtained, which is dimensioned in accordance with the rated surge voltage strength.
Fig. 2 shows the illustration according to fig. 1, with the difference that the mechanical breaking contact unit MK is advantageously associated with a load-side connection (in the series circuit of the mechanical breaking contact unit MK and the electronic breaking unit EU) and the electronic breaking unit EU is associated with a grid-side connection. Furthermore, the electronic interruption unit EU is embodied as a monopolar electronic interruption unit EU, i.e. in this example is arranged in the phase conductor, i.e. between the connections L1, L2. Furthermore, the electronic interruption unit EU has (at least one) semiconductor-based switching elements (=power semiconductors), which are shown in fig. 2. Furthermore, the semiconductor-based switching element has an overvoltage protection element, which is also shown in fig. 1. The control unit SE has an analog first subunit SEA and a digital second subunit SED. The digital second subunit SED may be, for example, a microprocessor or a Digital Signal Processor (DSP). The first subunit SEA, which is simulated, has at least one (current) comparator, as shown in fig. 2.
Fig. 3 shows a representation according to fig. 1 and 2 with a further detailed design. The control unit SE has two subunits, a preferably analog first subunit SEA and a preferably digital second subunit SED. The first subunit SEA has a (analog) current comparator CI. On the one hand, the current comparator CI is fed with the instantaneous current value DI of the current sensor unit SI. On the other hand, the current comparator CI is fed with the instantaneous current threshold SWI from the second subunit SED.
The current comparator CI compares the instantaneous current value DI with an instantaneous current threshold SWI and outputs a first current interruption signal TI when exceeded (in particular in terms of magnitude) as described in order to initiate an interruption of the electrical circuit.
The current interrupt signal TI may be fed to the logic unit LG, which combines the current interrupt signal TI with other interrupt signals and outputs the first interrupt signal TRIP to the electronic interrupt unit EU for semiconductor-based or high-ohmic interrupts.
In one embodiment, the current comparator CI buffers the instantaneous (current) threshold SWI so that these values are continuously available.
Wherein the instantaneous current threshold SWI is synchronized with the curve of the instantaneous voltage value over time (curve of the voltage over time). Thus, in the case where the instantaneous voltage is small (the phase angle of the sinusoidal alternating voltage is, for example, -30 ° to 0 ° to 30 °), a small instantaneous current threshold SWI is used (or exists), whereas in the case where the instantaneous voltage is large (the phase angle of the sinusoidal alternating voltage is, for example, 60 ° to 90 ° to 120 °), a large instantaneous current threshold SWI is used (or exists). The triggering time is thus advantageously largely dependent on the phase angle of the voltage, for example, so that the triggering time is below a first threshold value in time.
In the example according to fig. 3, the electronic interruption unit EU has a temperature sensor unit TEMP with one or more temperature sensors. Further temperature sensor units can likewise be provided in other units or in the protection switching device. The temperature sensor unit TEMP is connected to the control unit SE, in this example to a second subunit SED which adjusts the magnitude of at least one current threshold taking into account the temperature (of the plurality of temperature sensors or temperature sensor units) or the level of the temperature generated.
Furthermore, the instantaneous current value DI is fed to the second subunit SED. In a preferred embodiment, the instantaneous current value DI is digitized there by an analog-to-digital converter ADC and fed to the microprocessor CPU. The microprocessor CPU performs the determination or calculation of the instantaneous current threshold SWI, in particular in dependence on the temperature level obtained by the temperature sensor unit TEMP or/and by calculating the temperature level from the magnitude of the current/instantaneous current value. The instantaneous current threshold SWI determined by the second subunit SED or in particular by the microprocessor CPU is fed again to the first subunit SEA, in particular to the current comparator CI, to perform the comparison described above.
The second sub-unit SED or the first sub-unit SEA may have a digital-to-analog converter DAC for converting the (digital) current threshold SWI calculated in the second sub-unit SED into an analog current threshold SWI in order to perform an analog comparison in the analog first sub-unit SEA. In the example according to fig. 3, the digital-to-analog converter DAC is part of (or is assigned to) the (digital) second subunit SED.
The determination of the instantaneous current threshold SWI can advantageously be performed digitally in the second subunit SED or with a slower processing speed than a continuous comparison of the instantaneous current value DI in the first subunit SEA with the instantaneous current threshold SWI.
In an advantageous embodiment of the invention, the first subunit SEA can have a voltage comparator CU. On the one hand, the instantaneous voltage value DU of the voltage sensor SU is fed to the voltage comparator CU. On the other hand, the instantaneous voltage threshold SWU from the second subunit SED is fed to the voltage comparator CU.
The voltage comparator CU compares the instantaneous voltage value DU with an instantaneous voltage threshold SWU and outputs a voltage interruption signal TU when exceeded or not exceeded or in a range check in order to initiate an interruption of the voltage circuit.
The voltage interrupt signal TU can be fed to the logic unit LG, which combines the voltage interrupt signal TU with a (further) interrupt signal and outputs the first interrupt signal TRIP to the electronic interrupt unit EU for semiconductor-based or high-ohmic interrupts.
In one embodiment, the voltage comparator CU caches the instantaneous threshold SWU so that these values are continuously available.
Furthermore, in this embodiment, the instantaneous voltage value DU can be fed to the second subunit SED. In a further preferred embodiment, the instantaneous voltage value DU is digitized there by an analog-to-digital converter ADC and fed to the microprocessor CPU. The microprocessor CPU performs the determination or calculation of the instantaneous voltage threshold SWU. The instantaneous voltage threshold SWU determined by the second subunit SED or in particular the microprocessor CPU is fed again to the first subunit SEA, in particular the voltage comparator CU, to perform the comparison described above.
The determination of the instantaneous voltage threshold SWU can advantageously be performed digitally in the second subunit SED or with a slower processing speed than a continuous comparison of the instantaneous voltage value DU in the first subunit SEA with the instantaneous voltage threshold SWU.
According to a further embodiment, the second interrupt signal trigg can be output from the second subunit SED of the control unit SE, in particular from the microprocessor CPU, to the mechanical breaking contact system MK for current interruption of the electrical circuit, as is depicted in fig. 3.
The design of the control unit with the analog first subunit and the digital second subunit has the particular advantage that an efficient architecture is presented. The simulated first subunit may perform a very fast comparison of the instantaneous value and the threshold value, whereby a fast short-circuit identification may be achieved. The second subunit may perform a threshold calculation or adjustment independent thereof, which according to the invention is performed in dependence of the temperature level, which does not need to be performed as fast as the identification. The threshold value may be cached, for example, so as to be available for fast comparison. There is no need to continuously adjust the threshold.
Fig. 4 shows a further embodiment or variant according to fig. 1 to 3. Fig. 4 shows a part of a simple variant of the preferably analog first subunit SEAE and a part of an alternative variant of the preferably digital second subunit SEDE.
This part of the simple variant of the first subunit SEAE has a current comparator CIE, to which an instantaneous current value DI, in particular its magnitude, and an instantaneous current threshold SWI, in particular an instantaneous current threshold SWI which is likewise dependent on the magnitude, are fed. In this example, the current comparator CIE directly outputs the first interrupt signal TRIP, similar to the previous figures, to interrupt the low voltage circuit. The magnitude formation may be performed by one or another unit not shown. This alternative variant of the second subunit SEDEThis part of the scheme has a grid synchronization unit NSE. The (analog) instantaneous voltage value DU is fed to the grid synchronization unit NSE. The grid synchronization unit NSE determines the phase angle of the voltage from the fed (analog) instantaneous voltage value DUThe (analog) instantaneous voltage value DU fed is, for example, a sinusoidal ac voltage of the low-voltage circuit.
Alternatively, the amplitude U of the voltage UE and the expected time value or the expected value of the voltage UE may additionally be determined.
The expected value of the voltage UE is a filtered or regenerated or generated equivalent instantaneous voltage value DU.
The phase angle of the voltage DU can be determined, for example, by a so-called phase-locked loop (Phase Locked Loop) or a phase-regulating loop, abbreviated as PLL (and the expected value or amplitude U of the voltage UE). A PLL is an electronic circuit arrangement which influences the phase, and thus the frequency of a variable oscillator, by means of a closed control loop, so that the phase deviation between an external periodic reference signal (instantaneous voltage value) and the oscillator or a signal derived therefrom is as constant as possible.
In particular, therefore, the phase angle of the supplied mains voltage, i.e. the determined voltage value, can be determinedThe fundamental frequency and its amplitude, i.e. for example the (undisturbed or filtered) expected value of the (grid) voltage can also be determined.
Phase angle to be determined by grid synchronization unit NSE(and possibly the amplitude U of the voltage UE or/and the expected time value) is fed to a threshold unit SWE. The threshold unit SWE may have a threshold value for transients (phase dependent)A (scaled) curve of the time current threshold SWI. For example, in the case of sinusoidal ac voltages of low-voltage circuits, a (almost) sinusoidal current threshold curve, i.e. a sinusoidal change curve in the magnitude of the instantaneous current threshold SWI over a phase angle or cycle time (or (respectively) time) of 0 ° to 360 °.
The protection switching device SG can have a setting element, in particular a single setting element. With the setting element, in particular the single setting element, on the protection switching device SG, a limit value or a maximum value of the current threshold can be set. Alternatively, the limit value or maximum value of the current threshold value can also be fixedly predefined or programmed.
According to the invention, the current threshold curve is then scaled with respect to the limit value or the maximum value of the current threshold set by the setting element or fixedly predefined. For example, the amplitude (i.e., maximum) of the current threshold curve may be scaled with the limit/maximum of the current threshold.
For example, the current threshold may be 16A.
Due to the phase angle of the voltage present in the threshold unit SWEThe threshold unit SWE may transmit the instantaneous current threshold SWI to the current comparator CIE in synchronization with the instantaneous current value DI, so that a phase-dependent (phase angle-dependent) comparison may be made between the instantaneous current value DI and the instantaneous current threshold SWI.
In fig. 5, in variant 1 on the left, the temperature τ in degrees celsius with respect to the horizontal axis is shown chip The current threshold i in percent% on the vertical axis is shown sw.off Is an exemplary curve of the relative sizes of (a) and (b). For example, at 25 ℃ and below, the relative current threshold is 100%, i.e. the maximum of the at least one current threshold. At 150 ℃, the relative current threshold is 0%, i.e. 0 ampere, i.e. when there is current flowing, the interruption of the circuit is immediately performed.
The relative current threshold decreases linearly with increasing temperature over a range of temperatures. That is, at least one current threshold is reduced as the temperature increases. If the temperature drops again, the (relative) current threshold is increased again. That is, when the temperature decreases, at least one current threshold is increased.
In modification 2 on the right side of fig. 5, the temperature τ in degrees celsius with respect to the horizontal axis chip The current threshold i in percent% on the vertical axis is shown sw.off Another exemplary curve of the relative magnitudes of (a) is provided. In this example, the relative current threshold is 100%, i.e. the maximum of the at least one current threshold, before a temperature of 85 ℃. At 150 ℃, the relative current threshold is again 0%. At 125 ℃, the relative current threshold is 50%.
The temperature level may be a temperature level inside a housing of the protection switching device. More specifically, the temperature level may be a temperature level of the electronic interrupt unit EU. In particular, the temperature level may be a temperature level of a semiconductor-based switching element (i.e., a power semiconductor) of the electronic interrupt unit EU. The temperature of the other power semiconductors can likewise be determined. Based on the determined temperature, a relevant temperature may be determined for use as a temperature level of the protection switching device for adjusting the magnitude of the at least one current threshold, e.g. relatively adjusting the magnitude of the at least one current threshold.
According to a design, the respective temperature sensor unit is arranged at the respective position.
In an advantageous embodiment of the invention, the protection switching device is designed such that the temperature level is determined from the temperature sensor contained in the device and its determined temperature and the magnitude of the measured current, so that the calculation takes account of the magnitude of the instantaneous value of the current by means of the electrical and thermal model.
From a simple electrical model of the semiconductor-based switching element/power semiconductor (resistance in the on-state) and the instantaneous value of the measured current, the instantaneous value of the power loss generated in the semiconductor can be calculated or estimated. In addition, the temperature sensor/temperature sensor unit contained determines, for example, the temperature of the existing electronic interruption unit or the heat sink of the semiconductor-based switching element (power semiconductor).
The instantaneous value of the semiconductor chip temperature over time can be calculated using both information (instantaneous value of the losses in the power semiconductor, temperature in the device (preferably at defined locations of the thermal cooling chain, e.g. at the heat sink)) and thermal model of the cooling chain (semiconductor chip- > semiconductor housing- > heat sink- > environment).
This has the particular advantage that the thermal inertia of the thermal measurement by the temperature sensor unit does not lead to a delay in the temperature profile of the determined power semiconductor (semiconductor-based switching element).
Then, the determined speed of the semiconductor-based temperature of the switching element/semiconductor temperature is determined by the current/current value and the sampling speed of the calculation time in the corresponding control unit/microcontroller. These times are typically in the range of, for example, 10 to 500 mus.
This rapid temperature calculation thus provides decisive protection against thermal overload of the contained power semiconductors, thus leading to an increase in the robustness and thus reliability of the electronic protection switching device.
(direct thermal measurement with such a speed is not possible).
The magnitude of the at least one current threshold is advantageously adjusted by the control unit. The protection switching device is designed, for example, to adjust at least one current threshold value by the control unit (in order to prevent the current flow of the low-voltage circuit as a function of the temperature level of the protection switching device).
The adjustment of the at least one current threshold value as a function of the temperature level of the protection switching device is carried out, for example, by means of a calculation. In the example according to variant 1, the current threshold i as a function of temperature level is set to sw,off (τ chip ) The calculation of (2) is performed by:
i sw，off (τ chip ) Isw off (τchip) =current threshold according to temperature level
I sw，off ＝lswOff=maximum of current threshold
τ chip Temperature =τchip = (correlation)
Under the following conditions:
i sw，off (τ chip )＝I sw，off ＊[0 … 100％]
regarding variant 2 according to fig. 5, this is done in a similar way by:
also under the following conditions:
i sw，off (τ chip )＝I sw，off ＊[0 … 100％]
on the one hand, fig. 6 shows a curve of the magnitude of the grid-side voltage Vgrid in volts V for one cycle of sinusoidal alternating voltage on the left-hand vertical axis with respect to time in s on the horizontal axis. Such as a curve of the magnitude of the voltage Vgrid for one cycle of sinusoidal ac voltage in a low voltage ac circuit. The instantaneous voltage value of the voltage is given here in terms of time, wherein time is proportional to the phase angle (f=50 Hz).
On the other hand, fig. 6 shows on the right vertical axis the instantaneous current threshold (0 to 1) after scaling (in magnitude) in relation to the phase angle or in relation to the phase angle, with respect to time in s [ s ]. Here, the temporal (scaled) curve of the instantaneous current threshold corresponds to the instantaneous current threshold SWI (phase-dependent).
According to the invention, the temporal (scaled) curve of the instantaneous current threshold is scaled in correspondence with the limit value/maximum value of the current threshold set by means of the setting element or fixedly predefined. For example, the amplitude (scale 1) is set to 100A or, for example, 5 times the nominal current. In the case of a nominal current of, for example, 16A, for example, provision is made for
5×16a×1.414 (root No. 2) =113A
(root number 2= > peak value of instantaneous value of current)
Generally, the curve of the instantaneous current threshold corresponds to the curve of the voltage in the circuit, as shown in fig. 6. That is, for example, in the case of a triangle voltage curve, a triangle current threshold curve will be used. The background is the magnitude of the voltage determining (short-circuiting) the magnitude of the current rise. Thus, according to the invention, a low threshold is used at low pressure and a high threshold is used at high pressure to enable fast phase angle independent short circuit identification, which is temperature-wise adjusted.
According to fig. 6, the (periodic) instantaneous current threshold SWI has a minimum value. That is, a sinusoidal curve is not ideal (only approximately or nearly sinusoidal). The minimum value is greater than zero. The minimum value is greater than 5%, 10%, 15% or 20% of the maximum value, i.e. the amplitude of the current threshold curve, in particular in the range of 5 to 20%, for example (10% or 15%) of the maximum value, i.e. the amplitude of the current threshold curve. The minimum value occurs at the location or in the region of the zero crossing of the (sinusoidal) curve of the current threshold.
In the sinusoidal voltage profile over time in the low-voltage ac circuit, the voltage and the time profile of the voltage change threshold are synchronized in a phase-dependent manner such that the point in time of the amplitude of the voltage (maximum value) coincides with the point in time of the amplitude of the current threshold (maximum value), as shown in fig. 6.
Further, the area of the zero crossing point of the voltage coincides with the area of the minimum value of the current threshold.
The phase angle resolution determines the speed of the threshold calculation. In case of a phase angle resolution of 1 deg., i.e. for each complete phase angle of the voltage, there is a threshold, i.e. about one instantaneous threshold per about 55.5 mus. The switching off is preferably performed by an analog comparator, i.e. continuously, so that the switching off is significantly faster than the phase angle resolution (i.e. in the nanosecond range).
Alternatively, in a completely digital process, the following curve over time is applicable. The phase angle resolution determines the speed of recognition. In case of a phase angle resolution of 1 deg., i.e. for each complete phase angle of the voltage, there is a threshold, i.e. about one instantaneous threshold per about 55.5 mus, which means that a cut-off can be made after a minimum of about 60 mus. With higher phase angle resolution, shorter off-times can be achieved.
In this example, the values are then processed at least 18 kHz.
The current threshold value can also be stored (in a scaled manner) in a table, wherein the value is then adjusted if necessary.
Although the invention has been illustrated and described in detail with reference to specific embodiments, the invention is not limited to the examples disclosed, and other variations may be derived therefrom by those skilled in the art without departing from the scope of the invention.
Claims (23)
1. A protection switching device (SG) for protecting a low voltage circuit, the protection switching device having:
a housing (GEH) having a first connection (L1, N1) and a second connection (L2, N2) for conductors of a low-voltage circuit,
A series circuit of a mechanical breaking contact unit (MK) and an electronic breaking unit (EU), said series circuit electrically connecting said first and second terminals,
the mechanical breaking contact unit (MK) is capable of switching by opening contacts to prevent current flow in the low voltage circuit or closing contacts for current flow in the low voltage circuit,
the electronic interruption unit (EU) is switchable by means of a semiconductor-based switching element to a high-ohmic state of the switching element for preventing a current flow in the low-voltage circuit or to a low-ohmic state of the switching element for a current flow in the low-voltage circuit,
a current sensor unit (SI) for determining the magnitude of the current of the low-voltage circuit such that an instantaneous current value is present,
a control unit (SE) connected to the current sensor unit (SI), the mechanical breaking contact unit (MK) and the electronic breaking unit (EU), wherein a blocking of the current flow of the low-voltage circuit is initiated when at least one current threshold is exceeded,
the protective switching device is designed such that,
and adjusting the at least one current threshold according to the temperature level of the protection switch device.
2. Protection switching device (SG) according to claim 1,
it is characterized in that the method comprises the steps of,
the first connection (L1, N1) is a connection on the grid side and the second connection (L2, N2) is a connection on the load side,
the mechanical breaking contact unit (MK) is assigned to the load-side connection and the electrical breaking unit (EU) is assigned to the grid-side connection.
3. Protection switching device (SG) according to claim 1 or 2,
it is characterized in that the method comprises the steps of,
the at least one current threshold is adjusted as a function of the temperature level in such a way that, when the temperature increases, the at least one current threshold is reduced and, when the temperature decreases, the at least one current threshold is increased, in particular to a maximum value of the at least one current threshold.
4. The protection switching device (SG) according to claim 1, 2 or 3,
it is characterized in that the method comprises the steps of,
the temperature level of the protection switching device is a temperature level inside the housing in the protection switching device.
5. Protection switching device (SG) according to claim 1, 2, 3 or 4,
it is characterized in that the method comprises the steps of,
the temperature level of the protection switching device is the temperature level of the electronic interrupt unit (EU).
6. Protection switching device (SG) according to any of the preceding claims 1 to 5,
it is characterized in that the method comprises the steps of,
the temperature level of the protection switching device is the temperature level of the semiconductor-based switching element of the electronic interrupt unit (EU).
7. Protection switching device (SG) according to any of the preceding claims,
it is characterized in that the method comprises the steps of,
at least one temperature sensor unit (TEMP) is arranged in the protection switching device, which is connected to the control unit for determining a temperature level.
8. Protection switching device (SG) according to any of the preceding claims 1 to 6,
it is characterized in that the method comprises the steps of,
the temperature level is determined (calculated) from the magnitude of the measured current.
9. Protection switching device (SG) according to claim 8,
it is characterized in that the method comprises the steps of,
the temperature level is determined from the magnitude of the measured current in such a way that calculations are made taking into account the magnitude of the instantaneous value of the current, using an electrical model and a thermal model.
10. Protection switching device (SG) according to any of the preceding claims,
it is characterized in that the method comprises the steps of,
the adjustment of the at least one current limit value is performed continuously, in particular faster than 20ms, more particularly faster than 10ms or preferably faster than 1 ms.
11. Protection switching device (SG) according to any of the preceding claims,
it is characterized in that the method comprises the steps of,
the protection switching device is designed to compare the instantaneous current value of the determined magnitude of the current with the at least one current threshold value by means of an analog comparator, so that a blocking of the current flow of the low-voltage circuit is initiated when the magnitude of the current value exceeds the magnitude of the at least one current threshold value.
12. Protection switching device (SG) according to claim 11,
it is characterized in that the method comprises the steps of,
the protection switching device is designed to digitally calculate the at least one current threshold, to convert the calculated digital current threshold into an analog current threshold using a digital-to-analog converter (DAC),
the analog current threshold is fed to the comparator.
13. Protection switching device (SG) according to any of the preceding claims,
it is characterized in that the method comprises the steps of,
the protection switching device is designed to convert the temperature level into a digital temperature value, multiply the digital temperature value by a certain factor, and subtract the resulting product from the at least one current threshold value to obtain an adjusted current limit value.
14. Protection switching device (SG) according to any of the preceding claims 1 to 13,
it is characterized in that the method comprises the steps of,
the protection switching device is designed to convert the temperature level into a digital temperature value, to reduce the digital temperature value by a certain correction value, and to subtract the result from the at least one current threshold value to obtain an adjusted current limit value.
15. Protection switching device (SG) according to any of the preceding claims,
it is characterized in that the method comprises the steps of,
a voltage sensor unit is provided for determining the magnitude of the voltage of the low voltage circuit, so that there is an instantaneous voltage value,
there is a particularly periodic instantaneous current threshold (SWI) associated with a particularly periodic time-dependent curve of said instantaneous voltage value,
comparing the instantaneous current value (DI) with the instantaneous current threshold (SWI) in a phase-dependent manner, an interruption of the low-voltage circuit being initiated when the magnitude of the instantaneous current value exceeds the magnitude of the instantaneous current threshold (SWI) in magnitude.
16. Protection switching device (SG) according to claim 15,
it is characterized in that the method comprises the steps of,
the low voltage circuit has a sinusoidal voltage profile over time,
The instantaneous current threshold (SWI) has a current threshold curve which is almost sinusoidal over time, in particular in terms of magnitude, with a minimum value which is greater than zero, in particular greater than 5, 10, 15 or 20% of the maximum value,
the curves of the voltage (DU) and the current threshold (SWI) over time are synchronized in a phase-dependent manner such that the point in time of the amplitude of the voltage (DU) coincides with the point in time of the amplitude of the current threshold (SWI).
17. Protection switching device (SG) according to claim 16,
it is characterized in that the method comprises the steps of,
the area of the zero crossing of the voltage (DU) coincides with the area of the minimum value of the current threshold (SWI).
18. Protection switching device (SG) according to any of the preceding claims,
it is characterized in that the method comprises the steps of,
the protection switching device is designed such that the control unit (SE) adjusts the at least one current threshold value as a function of the temperature level of the protection switching device in order to prevent a current flow of the low-voltage circuit.
19. A method for protecting a low-voltage circuit with a protection switching device having a mechanical breaking contact unit (MK) which is connected in series with an electronic breaking unit (EU),
The mechanical breaking contact unit (MK) can be switched by opening a contact to prevent the flow of current in the low-voltage circuit or closing a contact for the flow of current in the low-voltage circuit,
the electronic interruption unit (EU) is switchable by means of a semiconductor-based switching element to a high-ohmic state of the switching element for preventing a current flow in the low-voltage circuit or to a low-ohmic state of the switching element for a current flow in the low-voltage circuit,
determining the magnitude of the current of the low voltage circuit, such that there is an instantaneous current value,
initiating a blocking of current flow to the low voltage circuit when the magnitude of the instantaneous current value exceeds at least one current threshold,
and adjusting the at least one current threshold according to the temperature level of the protection switch device.
20. The method according to claim 19,
it is characterized in that the method comprises the steps of,
the at least one current threshold is adjusted as a function of the temperature level in such a way that, when the temperature increases, the at least one current threshold is reduced and, when the temperature decreases, the at least one current threshold is increased, in particular to a maximum value of the at least one current threshold.
21. A computer program product comprising instructions which, when executed by a microcontroller, cause the microcontroller to support, in particular perform, a method according to any one of claims 19 to 20 with a protection switching device according to any one of claims 1 to 18.
22. A computer readable storage medium having stored thereon the computer program product of claim 21.
23. A data carrier signal carrying the computer program product according to claim 21.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
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| DE102020216416.9 | 2020-12-21 | ||
| EP21216150.9 | 2021-12-20 | ||
| EP21216150 | 2021-12-20 | ||
| PCT/EP2021/087105 WO2022136443A1 (en) | 2020-12-21 | 2021-12-21 | Circuit breaker device and method |
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| Publication Number | Publication Date |
|---|---|
| CN116724373A true CN116724373A (en) | 2023-09-08 |
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