WO2010145757A1

WO2010145757A1 - Control method for triggering an electronic safety switch

Info

Publication number: WO2010145757A1
Application number: PCT/EP2010/003363
Authority: WO
Inventors: Christian Strobl
Original assignee: Ellenberger & Poensgen Gmbh
Priority date: 2009-06-19
Filing date: 2010-06-02
Publication date: 2010-12-23
Also published as: DE102009025514A1

Abstract

The invention relates to a control method for triggering an electronic safety switch (1), which can be implemented with simple means, particularly with a low storage space requirement and/or low computing power. According to the invention, sampling values (i_B, p) of an input signal (i) relevant for triggering the safety switch (1) are continuously registered using a predetermined sampling frequency (f_m). In a first test stage, a first cumulative value (i_M1, p_M0) is formed from a number of registered sampling values (i_B, p), and a trigger signal (A) is generated if said first cumulative value (i_M1, p_M0) satisfies a predetermined first trigger criterion. In a further test stage, a second cumulative value (i_M2, p_M1) is formed from a number of determined first cumulative values (i_M1, p_M0), wherein the trigger signal (A) is generated even if said second cumulative value (i_M2, p_M1) satisfies a predetermined second trigger criterion.

Description

Description Control method for triggering an electronic circuit breaker

The invention relates to a control method for triggering an electronic circuit breaker. The invention further relates to an electronic circuit breaker operating according to this method.

A circuit breaker serves to automatically open an electrical load circuit upon the occurrence of a trip condition, i. to interrupt electrically. The tripping condition is usually an overcurrent (short circuit or overload). Additionally or alternatively, however, a circuit breaker may also be set up to trip in the event of a different trip condition, in particular in the event of under voltage or overvoltage.

In a conventional circuit breaker, the presence of the tripping condition is usually detected by a thermal and / or magnetic action principle. Thermal circuit breakers usually comprise a tripping element in the form of a load current flowing through the bimetal or wire, the thermally induced change in shape triggers the circuit breaker. In the case of magnetic circuit breakers, tripping usually takes place by direct energization of a magnet coil by the load current itself. An overcurrent circuit breaker with a thermal tripping principle is known, for example, from EP 0 616 347 B1. Another circuit breaker with an additional undervoltage release is known from EP 0 802 552 B1.

Circuit breakers with a thermal tripping principle in particular have the advantage over circuit breakers with other tripping principle that they respond to overcurrents of different strengths with a comparatively strongly varying tripping delay (holding time). Thus, a thermal circuit breaker interrupts the load circuit to be monitored in case of short circuit due to the then sudden heating of the triggering element quasi instanten. In the case of only a slight overload, however, the same circuit breaker triggers due to the in this case only gradually heating trigger element after a relatively long holding time. The holding time t _{H of} a thermal circuit breaker in this case varies continuously as a function of the current I flowing in the overcurrent case, namely usually approximately according to the relationship l ² tπ = constant. As a result of this load-dependent differentiated holding time difference, a thermal circuit breaker advantageously tolerates short-term overload cases by such a circuit breaker overload periods which are harmless due to their strength and duration for the load circuit to be protected, not triggers.

In contrast to a classic circuit breaker of the aforementioned type, the tripping condition is detected in an electronic circuit breaker by an electronic circuit, in particular by a microcontroller with control software implemented therein. The trip electronics, upon detection of the trip condition, generate a trip signal, which in turn is used to actuate, e.g. magnetic trigger leads. Electronic circuit breakers and control methods for driving them are e.g. from EP 1 383 217 A1 and DE 40 00 627 A1.

The triggering electronics of a conventional electronic circuit breaker is often based on characteristic tables that simulate the tripping behavior of a thermal circuit breaker. Such a triggering electronics is - with sufficiently finely graded load dependence of the holding time characteristic - usually relatively complex to implement. For example, the control electronics, when formed by a microcontroller, often have a comparatively high demand for computational power and / or memory. The technical requirements of the control electronics, in particular the storage space and computing power requirements, thereby increase disproportionately with increasing differentiation (gradation) of the tripping characteristic.

The invention is based on the object to provide a control method for triggering an electronic circuit breaker, with simple means, in particular low storage space requirement and / or lower Computing power is feasible. In particular, the control method should also be flexibly adaptable to different requirements with regard to the load-dependent tripping characteristic. The invention is further based on the object of specifying an electronic circuit breaker suitable for carrying out the method.

With regard to the control method, the object is achieved according to the invention by the features of claim 1. Thereafter, samples of a relevant for the triggering of the circuit breaker input signal at a predetermined sampling frequency are continuously detected. In a first test stage, a first sum value is formed over a predetermined number of sampled values acquired, and a trigger signal is generated when this first sum value fulfills a predetermined first triggering criterion. In a further test stage, a second sum value is formed over a predetermined number of first sum values determined, the trigger signal also being generated when this second sum value fulfills a predetermined second triggering criterion.

The method described above is preferably designed for triggering the circuit breaker in the event of overcurrent (short-circuit or overload). In this case, the current intensity of the current flowing in the load circuit to be monitored is expediently used as trigger-relevant input signal. However, other input signals, in particular the voltage present in the load circuit, a temperature measurement signal, etc. can also be used as an input signal in the context of the control method according to the invention.

Instead of sampling values which directly reproduce the (time-dependent) value of the input signal (that is to say the current intensity in the load circuit), sample values which represent the value of a quantity derived from the input signal can also be used for determining the first summation value within the scope of the invention. Derivative quantities are in particular the absolute value of the input signal, a value proportional to the input signal or its absolute value, the square or some other polynomial of the input signal, etc. The "first summation value" denotes any variable which is based on an optionally scaled sum of a plurality of sampled values, in particular the simple sum of a plurality of sampled values, an average formed from a plurality of sampled values or a variable proportional or squared thereto, etc.

Likewise, the "second sum value" denotes any variable which is based, directly or indirectly, on a possibly scaled sum of a plurality of first sum values.

The first or second triggering criterion is, in particular, a threshold value comparison. In this case, the triggering signal is generated in particular when the first summation value or the second summation value exceeds a respectively assigned threshold value.

In the context of the invention, the method principle described above with reference to only two summation formations can be extended to an arbitrary number of test stages and summation circuits connected in cascade-like fashion. Generally, in the nth test stage (n = 2, 3, 4, a number of summation values of the (n-1) -th test stage formed an n-th sum value, and generates the trigger signal even if the n-th sum value meets a predetermined n-th trigger criterion.

The core idea of the control method described above is to perform a multistage test based on a cascading sum over samples of the input signal or the quantity derived therefrom. In the context of this cascade structure, the or each further test stage connected downstream of a first test stage uses the sum values determined in the respectively preceding test stage for the calculation of a superordinate total value.

The hold time attributable to a test stage increases in proportion to the number of samples taken into account in the summation made in this test stage. Since each downstream test stage has at least two summing If the values of the upstream test stage are taken into account, the hold time from each test stage to the next test stage is at least doubled. Within a multistage test cascade, the hold time increases exponentially (in terms of magnitude).

Due to the cascade-like averaging, the memory required to calculate the summation values increases, but (on the order of magnitude) only linearly with the number of test stages. The exponential staggering of the holding times is thus achieved with an expenditure of computing power and storage space requirement, which increases only proportionally with the number of test stages. The control method can therefore be technically realized by means of a comparatively simple control electronics, in particular by means of a comparatively simple microcontroller.

In the sense of an optimized utilization of information with as little computation as possible, two temporally successive first summation values are preferably always determined from overlapping-free sequences of the sampled values. Each of these samples is therefore used only once for the determination of a first sum value, and then discarded. Conveniently, consecutive first summation values are also calculated from two sequences of samples which adjoin one another directly, so that each detected sample is taken into account exactly once in the determination of a first summation value.

In a corresponding manner, preferably two consecutive second (and possibly nth) sum values are determined from overlap-free sequences of the first (or (n-1) th) sum values.

Furthermore, the first sum value is preferably always calculated from a contiguous sequence of consecutive samples. In other words, the first sum value is calculated from a number of immediately consecutive samples. Likewise, preferably the second and possibly n-th sum value formed from a number of temporally immediately successive first or (n-1) -th cumulative values.

In a numerically uncomplicated execution of the control program, the samples are read to form the first sum value in a so-called first-in-first-out memory (also: shift register) whose number of storage locations corresponds to the number of samples to be considered in the summation. In order to ensure in a particularly simple manner that the first sum value is always formed from overlapping sequences of samples, this memory is always read only after one of its number of storage locations corresponding number of measuring cycles. With two memory locations, the memory is therefore read out after every second measuring cycle. In other words, the respective memory is always read out only when it is completely filled up with new (that is, not yet taken into account in the previous summation value) samples. A corresponding method is preferably also used to determine the second and possibly any further sum value.

In a preferred variant, the control method for triggering the circuit breaker is designed in the event of a short circuit. In this variant of the method, the first summation value is expediently calculated from sampled values which represent a measure of the absolute value of the current intensity of the load current. In a further variant of the method, the control program for triggering the circuit breaker in case of overload is formed. In this variant of the method, the first summation value is expediently calculated from sampled values which represent a measure of the squared current intensity of the load current. In a preferred embodiment of the circuit breaker, the two variants of the method described above are performed parallel to each other and simultaneously. The method thus has a short-circuit release string and an overload release string in this embodiment.

Preferably, in particular for the short-circuit release, the control method in an expedient embodiment in addition to an immediate triggering step, at which the trigger signal is already generated even if a single sample meets a predetermined triggering criterion, in particular exceeds an associated threshold value.

In an expedient further embodiment, the method is designed such that it can be used both for monitoring a DC circuit and for monitoring an AC circuit. For this purpose, the sampling frequency is chosen such that it is an integer multiple of the line frequency of the alternating current to be monitored. At a normal mains frequency of 50Hz, the sampling frequency is an integer multiple of 50Hz. In an expedient embodiment, the sampling frequency is at least 3 times the mains frequency. However, the ratio of the sampling frequency to the network frequency is preferably in the two-digit range, in particular at 20.

In a preferred variant of the method, in particular for the overload detection, the first summation value is formed over one or more full periods of the alternating current to be monitored if necessary. In other words, the number of acquired samples corresponding to one or more full oscillations of the alternating current is used to calculate the first summation value, so that the number of samples taken into account for determining the first summation value corresponds to the ratio of the sampling frequency to the mains frequency or to an integer multiple of this ratio , In this case, the rms value of an alternating current variable, in particular the rms current intensity or effective voltage, is calculated as the first summation value.

With respect to the circuit breaker, the above object is achieved by the features of claim 11. Thereafter, the circuit breaker comprises an insulating housing, a switch contact for reversible contact closure (ie opening and closing) of a load circuit to be monitored, a release magnet, which via a trigger mechanism on the switch contact acts, as well as a triggering electronics for controlling the trigger magnet. The triggering electronics is in this case for automatically carrying out the above-described Set up control method in one of its variants, ie designed circuit and / or program technology.

The triggering electronics is in a preferred embodiment of the circuit breaker in the form of a microcontroller, in which the control method is implemented by software in the form of a control program.

Embodiments of the invention will be explained in more detail with reference to a drawing. Show:

1 in a three-dimensional exploded view of an electronic circuit breaker,

2 is a sectional view of the circuit breaker in an OFF position,

3 in a representation according to FIG. 2 the circuit breaker in an ON position in a non-triggered state, FIG.

2 in the illustration of FIG. 2, the circuit breaker in the ON position, but in a triggered state,

5 shows the circuit breaker in a section V-V of FIG. 2,

6 is a block diagram of a control electronics for controlling the circuit breaker,

7 and 8 in current-time diagrams respectively show the time sequence of a control system implemented in the control electronics according to FIG. 6 for triggering the circuit breaker in the event of a short circuit or overload, and FIG

9 shows in a time-current diagram two characteristics that characterize the tripping behavior of the circuit breaker in the event of a short circuit or overload.

Corresponding parts and sizes are always provided with the same reference numerals in all figures.

Fig. 1 shows an exploded view of an electronic circuit breaker 1. The circuit breaker 1 is designed here as an overcurrent circuit breaker. Additive- lent triggers the circuit breaker 1 when falling below a predetermined undervoltage threshold.

The circuit breaker 1 comprises a housing 2 made of insulating plastic, which in turn comprises a housing pan 3 and a housing cover 4. The closed housing 2 has substantially the shape of a flat square, which is closed on three narrow sides. On the fourth narrow side, which is referred to below as the front side 5, a tilting rocker switch 6 is used to activate or deactivate the circuit breaker 1 in the assembled state as a control element. A to the front 5 opposite narrow side of the housing 2 is referred to below as the rear wall 7. The two adjacent (opposite) narrow sides of the housing 2 form the side walls 8 and 9, respectively.

The housing pan 3 is essentially formed by a housing bottom 10, the rear wall 7, and by the side walls 8, 9, while the housing cover 4 is essentially formed by a rectangular plate 11, the edge with approximately right-angled formed detent eyelets 12 for locking corresponding locking lugs 13 of the side walls 8 and 9 is provided. Furthermore, at right angles to the plate 11 in the region of the rear wall 7 edge facing pins 14 are formed, which are approximately accurately inserted in complementary slots 15 of the rear wall 7.

The circuit breaker 1 further comprises a printed circuit board 20, which is used in the assembled state substantially parallel to the housing cover 4 in the housing 2.

On the circuit board 20, three electrical contact rails 21, 22 and 23, and a substantially serving as a trigger element of the circuit breaker 1 electromagnet 24 soldered. Furthermore, a triggering electronics 25, not shown here, is arranged on the printed circuit board 20 for controlling the electromagnet 24. The contact rails 21 and 23 serve for the contact closure with a load circuit 26 to be monitored (FIG. 3, 6). The contact rail 22 serves as a printed circuit board connection for supplying voltage to the tripping electronics 25 and the electromagnet 24.

The circuit breaker 1 further comprises a triggering mechanism 30 for actuating and releasing. The triggering mechanism 30 in turn comprises, in addition to the switching rocker 6, a switching lever 31, a release lever 32, and a plunger 33.

In Fig. 2, the circuit breaker 1 is shown in a sectional side view in an assembled state. For orientation, a longitudinal direction Y parallel to the side walls 8, 9 and a transverse direction X directed from the side wall 8 to the side wall 9 are indicated here.

From Fig. 2 it can be seen that the contact rails 21, 22 and 23 are aligned in their main surface extent each approximately parallel to the side walls 8 and 9, and thus approximately at right angles to the surface area of the circuit board 20. The contact rails 21 and 23 are in each case arranged in the immediate vicinity of one of the side walls 8 and 9, while the contact rail 22 is arranged approximately centrally between the two other contact rails 21, 23. Each of the contact rails 21, 22, 23 is guided for connection purposes with a free end 34, 35, 36 in each case through a corresponding slot 37 in the rear wall 7 to the outside. Each slot 37 is closed on the housing cover 4 side facing in the assembled state otherwise by one of the pins 14.

To the contact rail 21 is in the region of its remote from the free end 34 fixed end 40 an approximately perpendicularly projecting leaf spring-like contact spring 41 is attached, which in turn freiendseitig has a contact surface 42.

At the contact rail 23, at the corresponding fixed end 44, a likewise projecting approximately at right angles, corresponding to the contact surface 42, is arranged. contact surface 45 is formed. The assembly formed from the contact spring 41, the contact surface 42 and the contact surface 45 is hereinafter referred to as the switching contact 46.

The contact spring 41 extends approximately in the transverse direction X over the housing width, so that the contact surfaces 42 and 45 for reversible closing of the load circuit 26 can be brought into contact.

Between the two contact rails 21 and 23 of the electromagnet 24 is arranged, wherein this with the longitudinal axis 50 of its bobbin 51, i. in longitudinal extent of its magnetic core 52, approximately along the transverse direction X is aligned. He is soldered by means of solder contacts 53 on the circuit board 20. At its side surface 9 side facing the magnetic core 52 protrudes from the bobbin 51 out.

Seen in the longitudinal direction Y between the electromagnet 24 and the contact spring 41, the release lever 32 is arranged. The release lever 32 has an approximately rectangular shape with a long leg 55 (approximately in the transverse direction X) and a short leg 56 (approximately in the longitudinal direction Y). The impact point of the two legs 55,56 is referred to below as knee 57. In the region of the knee 57, the release lever 32 is pivotally mounted on a pin 59 (shown in phantom) of the housing 2.

On the long leg 55, the plunger 33 is pivotally mounted at its end facing away from the knee 57 via a film hinge 60. The plunger 33 extends, starting from the long leg 55 in the longitudinal direction Y to the switching rocker. 6

The shift lever 31 is seen in the longitudinal direction Y above the contact spring 41 is arranged. It is formed by a substantially approximately triangular, rigid part, which is guided with a pin 61 in a slot guide 62 of the housing 2. The switching rocker 6 comprises a shell-shaped body 63, as well as a projecting into the housing 2 shaft 64. By means of a passage 65 in the shaft 64, the rocker switch 6 is pivotally mounted on a pin 66 of the housing 2.

The switching rocker 6 is coupled to the shift lever 31 via a journal 67 arranged at the free end of the shaft 64, which engages in an approximately hockey-club-shaped guide 69 (FIG. 3) of the shift lever 31. The guide 69 is optionally formed as a groove or slot. In addition, the switching rocker 6 corresponds via the plunger 33 with the release lever 32nd

The shift lever 31 in turn acts on the one hand by means of a retaining lug 70 with a retaining shoulder 71 on the short leg 56 of the release lever 32 together. On the other hand, the shift lever 31 acts on the contact spring 41 via an active surface 72.

The release lever 32 corresponds to a magnetic yoke 73, which is snapped by means of two locking angle 74 on this and cushioned by means of a magnet yoke 73 and release lever 32 clamped compression spring 75, with the magnetic core 52 of the electromagnet 24th

Fig. 2 shows the circuit breaker 1 in an OFF position of its rocker switch 6. In the OFF position, the rocker switch 6 is biased by the spring force of a leg spring 81 in the tilt position shown in Fig. 2.

In the OFF position, the shift lever 31 is released, i. he acts on neither the contact spring 41 nor the release lever 32. The contact spring 41 is in a rest position in which the contact between the contact surfaces 42 and 45 is interrupted.

In the OFF position, the rocker switch 6 further pushes the plunger 33 downward by urging the free plunger end 87 in the longitudinal direction Y, whereby the magnetic yoke 73 is brought into contact with the magnetic core 52. If the electromagnet 24 is energized via the tripping electronics 25, the magnetic yoke 73 and the tripping lever 32 are held in the position shown in FIG. 2 by magnetic closure with the electromagnet 24. If the switching rocker 6 is now tilted into an ON position shown in FIG. 3, the shift lever 31 first strikes against the retaining shoulder 71 of the release lever 32 with the retaining lug 70. As a result of the two-point bearing on the retaining shoulder 71 and the 69 inserted in the guide pin 67 of the shift lever 31 is pivoted with further tilting of the rocker switch 6 (clockwise in FIG. 3). He thereby proposes with the active surface 72 on the contact spring 41 and pushes them until the contact closure of the contact surfaces 42 and 45 in the longitudinal direction Y down. The load circuit 26 is closed in this state via the contact rails 21 and 23 and via the contact spring 41.

When triggered, the solenoid 24 is deactivated by the triggering electronics 25, i. de-energized, and thus the magnetic yoke 73 released. The release lever 32 is pivoted as a result of the action of a leg spring 92 in the counterclockwise direction about the knee 57 in the position shown in Fig. 4.

As a result of the lack of negative feedback of the shift lever 31 is pivoted counterclockwise in the position shown in Fig. 4, in which he releases the contact spring 41 again, so that the contact surfaces 42nd and 45 are separated. This triggering mechanism is in particular also when the switching rocker 6, in the ON position shown in FIG. 4 is blocked (free release).

If the rocker switch 6 is not blocked in the ON position, it tilts back under the action of the leg spring 81 in the OFF position shown in FIG.

5, the circuit breaker 1 in an angled cross-section VV of FIG. 2 is shown. This illustration shows that the printed circuit board 20 abuts with a first edge 96 approximately at the rear wall 7 and with a thereto opposite edge 97 projects into the switching rocker 6. From Fig. 5 it is also seen that the moving parts of the release mechanism 30, namely the rocker switch 6, the shift lever 31 and the release lever 32 with the plunger 33 including the associated springs 81 and 92 are all arranged on the side facing away from the housing cover 4 side of the circuit board 20 are.

The printed circuit board 20 is assembled outside the housing 2 with the contact rails 21, 22, 23 of the contact spring 41 and the electromagnet 24 to form a firmly connected preassembled module. This pre-assembly, which includes all current or live parts of the circuit breaker 1 is inserted as a whole into the housing pan 3 with the tripping mechanism 30 inserted therein. Subsequently, only the housing cover 4 has to be clipped onto the housing trough 3 in order to complete the installation, which is therefore very unostentatious overall.

The triggering electronics 25 is formed in the illustrated embodiment, at least substantially by a microcontroller. In the microcontroller, a control program 100 shown in greater detail in FIG. 6 is implemented by software, which automatically carries out a method described in more detail below for triggering the circuit breaker 1 in the event of a short circuit or overload.

The control program 100 comprises two parallel functional strands, namely a (short-circuit tripping) strand 101 and an (overload tripping) strand 102, which branch off from a common strand 103.

In the common train 103, the (load) current i in the load circuit 26 is first determined by means of a current sensor 104 as an input signal. The current sensor 104 (formed, for example, by a shunt or a current transformer) outputs as an output signal an analog current measurement signal i _A in the form of a current-proportional voltage to a downstream analog-digital (AD) converter 106. In the AD converter 106, which is preferably an integral part of the microcontroller, the analog current measurement signal is YES in time with a (measuring ) Clock frequency f _m with a resolution of nm bit (here nm = 8) in a digital current measurement signal i _D converted.

The current measurement signal I ^" D is generated such that

- i _D = 0 of a measured current i = -C- I _N ,

- i _D = 2 ^{nm 1 of} a measured current i = 0, and

- i _D = 2 ^{nm of} a measured current i = + C- I _N correspond. With I _N here the rated current of the circuit breaker 1 is designated. The constant C is - depending on the trigger sensitivity of the circuit breaker 1 - to values between about 3 and 20, for example set to C = 15.

The circuit breaker 1 is provided primarily for monitoring an AC load circuit. The measurement clock frequency f _m is therefore set to a multiple, in particular to 20 times the usual mains frequency f _N (that is to f _m = IkHz at a network frequency of f _N = 50 Hz). Nevertheless, the circuit breaker 1 can be used to monitor a DC load circuit without the control program 100 having to be changed for this purpose.

From an AD converter 106 software downstream amount module 107 is according to the equation |

generates a digital (current) magnitude signal i _β , which essentially corresponds to the absolute value of the load current intensity i. The magnitude signal i _B flows as input into the sub-strings 101 and 102 of the control program 100.

In a zeroth test stage of the short-circuit release line 101, the comparison in a module 11O ₀ with the clock frequency f _m of each measured measure sample of the magnitude signal i _B with a discrete characteristic point k ₀ a stored (short-circuit tripping) characteristic K (Fig. 9). The comparison module 11O ₀ remains inactive as long as the sample of the magnitude signal i _B does not exceed the characteristic point ko (i _B <k ₀ ). Otherwise (i _B > k ₀ ) is the comparison module 11Oo a trigger signal A, due to which the energization of the electromagnet 24 is interrupted, and the circuit breaker 1 is thus triggered. The current measurement signal i _D , or the magnitude signal i _B thus contains digital samples of the current i to discrete, each with a time interval of f _m ^"1 consecutive sampling times.

The characteristic point ko represents the so-called instantaneous triggering threshold. The value of the characteristic point ko is a measure of the maximum permissible overcurrent intensity on average over a holding time t _H (FIG. The hold time t »corresponds to the simple inverse clock frequency f _m or the simple (measurement) cycle time tm (FIG. 7) (tH = t _m = f _m ^{" 1} , here t _H = 0.001 s) Amount signal iß, which exceeds the characteristic point ko, so enough to trigger the circuit breaker 1.

In a - subsequent - first test stage of Kurzschlussauslösestrangs 101 is at the clock frequency f _m , ie in each measuring cycle, the respectively determined sample of the current amount i _B in a first (First-ln-First-Out) memory 113-ι with a number written by (here exemplary: two) memory locations.

Always after one of the number of storage spaces corresponding number of measuring cycles - indicated by the clock symbols 115 - forms a sum module 12O ₁ a rounded average JM _I from the stored in the memory 11S ₁ samples of the magnitude signal i _B - In two memory locations of the mean value i _M i is thus the half clock frequency f _m / 2 = 500Hz formed. A stored in the memory 113i sample of the magnitude signal is is thereby always considered only once in the averaging. Illustratively speaking, the memory 113i is always evaluated only when it is completely filled with new samples of the magnitude signal i _B.

The mean value i _M i is supplied as a test variable to a subsequent comparison module 110i. The comparison module 110i compares this mean value JM _I again with an associated characteristic point ki of the characteristic curve K and outputs - analogous to the comparison module 11O ₀ - the trigger signal A, if the mean value i _M i exceeds the characteristic point ki in terms of value (i _M i> ki) , The characteristic point ki is a measure of the mean maximum permissible overcurrent intensity over a holding time t _Hl which corresponds to twice the cycle time t _m (t _H = 2 t _m = 2 f _m ^-1 , in this case t _H = 0.002 s).

The mean value i _M i of the first test stage is fed as an input quantity to a second test stage, which analogously to the first test stage has a further (first-in-first-out) memory 113 ₂ , a further sum module 12O ₂ and a further comparison module 110 ₂ . Also in terms of their function, the second test stage is similar to the first test stage, with the difference that the mean value ΪM _{I of} the first test stage is supplied to the memory 113 ₂ instead of the magnitude signal and the mean value i _M2 generated by the summation module 12O ₂ is the same as that four divided clock frequency f _m / 4 = 250 Hz is generated. A characteristic point k ₂ assigned to the comparison module 11O ₂ as a triggering criterion is thus a measure of the maximum overcurrent intensity on average over a holding time X _H which corresponds to the quadruple cycle time t _m (t _H = 4 t _m = 4-f _m ^-1 ; t _H = 0.004s).

The second test stage is followed in cascade by one or more further test stages of the nth order (n = 3, 4,...), Which in turn correspond to the second test stage in terms of structure and function, and each by a (First-ln-First -Out-) memory 113 _n , another sum module 12O _n and another comparison module 11O _{n are} formed. In this case, the memory 113 _π receives in each case as an input signal the mean value i _M (ni) of the directly superordinate test stage (n-1) th order. From the sum module 12O _{n of} the n-th test stage, a mean value i _Mn is always generated with the clock frequency f _m / 2 "divided by 2 ⁿ , which is compared with a characteristic point k _n in the comparison module 11O _n . The characteristic point k _n is a Measure for the maximum overcurrent on average over a holding time t _H , which corresponds to 2 ⁿ times the clock time t _m (t _H = 2 ^π -t _m = 2 ⁿ V).

The principle of this cascaded averaging is again illustrated in Fig. 7, in which the course of the magnitude signal i _SS and the average values JMI and JM ₂ against time t disposed in superposed, is compared with synchronous diagrams. It can be deduced directly from this representation that, as a result of the cascade-like averaging, the hierarchically consecutive test stages Check changes in the load current on respective time scales, which increase exponentially with the order of steps. A measure of the time scales associated with the test stages in this case is the hold time t _{H of} the respective test stage:

-1 n-th test stage (n = 0,1, 2, ...): _H t = 2 ^{π •} t _m = 2 ^{π •} f _r

In the overload trigger sub-string 102, a square signal p with p = i _ß ^■ i _ß calculated as shown in FIG. 6 first in a squaring module 130 from the magnitude signal i _ß as a measure of the power of the load current.

This square signal p is read in with the clock frequency f _m into a first-in-first-out memory 131 of a zeroth test stage of the sub-string 102. The memory 131 has - again for the use of the circuit breaker 1 for securing an AC load circuit - a number q of memory locations, which corresponds to the ratio of the clock frequency f _m to the usual network frequency f _N or a multiple thereof:

q = j ^■ fm / f N with j = 1, 2,3, ...

With a network frequency of f _N = 50 Hz and a clock frequency of f _m = 1 kHz, the memory 131 has in particular q = 20 memory locations.

A sum module 132 connected downstream of the memory 131 always calculates a rounded mean value p _M o from the values of the square signal p stored in the memory 131 according to a number of measuring clock pulses corresponding to the number q-indicated by the clock symbols 133. The mean value p _M o hereby represents a measure of the effective power of the load current. At twenty memory locations of the memory 131, the mean value P _{MO is formed} with a clock frequency f _e = f _N = 1/20 f _m corresponding to the line frequency f _N. A value of the square signal p stored in the memory 131 is thereby always taken into account only once in the averaging. The mean value PMO is compared in a downstream comparison module 136o with a characteristic point Uo of a stored (overload tripping) characteristic U (FIG. 9), the comparison module 136o generating the tripping signal A when the mean value PMO exceeds the square of the characteristic point Uo in terms of value (PM _O > U ₀ ² ). The square Uo ^{2 of} the characteristic point U ₀ thus represents a measure of the maximum permissible effective power of the load current.

Analogously to sub-string 101, hierarchically downstream test stages are also provided in sub-string 102, which correspond in terms of design and function to the corresponding test stages of sub-string 101. Each of these test stages comprises

a first-in-first-out memory 138 _n with two memory locations, to which the mean value P _{M (Π} - _{I) of} the respectively higher-level test stage is supplied as an input variable,

a sum module 14O _n , which calculates with 1/2 ^π- fold clock frequency 1/2 ^π f _e a mean value P _{MΠ of} the values contained in the memory 138 _n , and

a comparison module 136 _n , which compares this mean value PM _Π with the square U _n ^{2 of} an associated characteristic point U _n and generates the triggering signal A in the case P _MΠ > U _n ² .

The counting variable n = 1, 2, 3,... In this case again denotes the hierarchical order of the respective checking stage.

In exemplary embodiment of the control program 1, the sub-string 101 has five test stages (n = 0,1, ..., 4), while the sub-string 102 has thirteen test stages (n = 0,1, ..., 12).

In FIG. 8, the waveform of the squared signal p and the mean values of PM is _O and p _M i shown in comparison analogous to Fig. 7. It can be deduced from this representation that the test stages of the second sub-string 102 again check changes in the power of the load current-with the exception of the zeroth test stage-to exponential times with the step order: nth test stage (n = 1, 2, ...): t _H = 2 ^{n •} f _e ^{~ 1}

In the modules 107, 11O _n (n = 0,1, 2, ...), 12O _n (n = 1, 2, ...), 130, 132, 136 _n (n = 0,1, 2, ...), and 14O _n (n = 1, 2, ...) are software components of the control program 100. In the (first-in-first-out) memories 113 _n (n = 1, 2, ...), 131 and 138 _n (n = 1, 2,...) Are preferably software-allocated (ie reserved) areas of a common main memory of the microcontroller executing the control program 100.

The characteristic curves K and U are shown in FIG. 9 in a log-log plot versus the hold time t _H (plotted here on the ordinate). On the abscissa of the diagram, the current i is plotted as a percentage of the nominal current intensity I _{N of} the circuit breaker 1.

Corresponding to the respective number of test stages, the characteristic curve K comprises four characteristic curve points ko, ki,..., Ic ₄ , while the characteristic curve U is formed of thirteen characteristic points U ₀ , UI,..., U1 ₂ . From FIG. 9 it becomes clear that the characteristic curves K and U cover a holding time interval of 10 ^'3 s <\ »≤ 10 ² s without overlap. The characteristic K determines the tripping behavior of the circuit breaker 1 on time scales below the inverse mains frequency (fo <

= 20ms), while the characteristic curve U determines the tripping behavior of the circuit breaker 1 on time scales above the inverse mains frequency (t _H > fig ^"1 = 20 ms).

The current values (tripping values) of the characteristic points k _n and U _n can be chosen freely, in a departure from the example shown in FIG. 9. The characteristic points k _n and U _n are expediently selected such that the characteristic curves K and U each fall strictly monotonically, so that the holding time t _{H is} always shorter, the higher the current value of the respective characteristic point k _n or U _n .

The number of characteristic points k _n and U _n can basically be freely selected for each of the characteristic curves K and U. The number of test stages of sub-branches 101 and 102 is always equal to the number of characteristic points k _n and U _n of each associated characteristic curve k _n or U _n with respect to the associated holding time tπ a test stage of the sub-string 101 and 102, respectively. Alternatively, it is also conceivable

to provide more test stages within a sub-string 101 or 102 than the associated characteristic curve characteristic points k _n or U _n and / or

to select the characteristic points k _n and / or u _n at least in part in such a way that the holding time t _{H associated} with these characteristic points k _n or U _n does not coincide with the holding time tπ assigned to a test stage.

In these cases, instead of the characteristic points k _n or U _n, threshold values are fed to the test stages which are derived from the characteristic points k _n or U _n by interpolation or extrapolation in accordance with the holding times tn assigned to the test stages.

Also, the exponential increase of the hold time U with increasing level order n can - in an alternative embodiment of the invention - be varied by the successive within the same sub-string 101 or 102 memory 113 _n (n = 1, 2, ...) and 138 _n ( n = 1, 2, ...) are defined with a varying number of memory locations.

The circuit breaker 1 has a construction due to a passive undervoltage tripping function, especially since the triggering mechanism 30 forcibly triggers when the voltage applied between the contact rails 21 and 22 voltage is no longer sufficient to supply the electromagnet 24 and / or the triggering electronics 25 sufficiently with electrical energy. This function can be used in particular to remotely trigger the circuit breaker 1 by means of a contact rail 22 downstream switch.

In addition, the circuit breaker 1 optionally has an active overvoltage triggering function, which is implemented, in particular by software engineering, in an undervoltage triggering block (not shown) of the control program 100. As part of this active undervoltage release, the control program 100 detects continuously and in parallel with the sequence of the program shown in FIG. partly the amount (in the AC voltage case the effective amount) of the applied voltage between the contact rails 21 and 22 and compares the detected voltage amount with a stored threshold value. In this case, the control program 100 generates the trigger signal A when the detected voltage amount falls below the threshold value.

LIST OF REFERENCE NUMBERS

1 circuit breaker

2 housings

3 housing tray

4 housing cover

5 front side

6 rocker switch

7 rear wall

8, 9 side wall

10 caseback

11 plate

12 detent lugs

13 latch

14 cones

15 slot

20 circuit board

21, 22, 23 contact rail

24 electromagnet

25 trip electronics

26 load circuit

30 release mechanism

31 shifter

32 release lever

33 pestles

34, 35, 36 Free

37 slot

40 festivals

41 contact spring

42 contact surface

44 Festende

45 contact area

46 switching contact longitudinal axis

bobbins

magnetic core

solder contact

long legs

Kurzschenkel

knee

spigot

Film hinge

spigot

Langlochfϋhrung

body

shaft

execution

spigot

guide

retaining nose

retaining shoulder

effective area

yoke

Rest angle

compression spring

Leg spring

plunger end

Leg spring

edge

control program

strand

strand 104 current sensor

106 AD converter

107 Amount module

11O _n comparison module (n = 0,1,2, ...)

113 _n memory (n = 1,2, ...)

115 clock icon

12O _n sum module (n = 1,2, ...)

130 squaring module

131 memory

132 summation module

133 clock icon

136 _n comparison module (n = 0, 1, 2, ...)

138 _n memory (n = 1,2, ...)

14O _n sum module (n = 1, 2, ...)

A Release signal fe Clock frequency fm Clock frequency f _N Line frequency i (load) current

YES current measurement signal eats (current) magnitude signal

ID current measurement signal

Mean value (n = 1,2, ...)

K (short-circuit tripping) characteristic curve characteristic point (n = 0,1,2, ...)

P square signal

PMn mean value (n = 0,1, ...) q number t time t _H hold time tm cycle time

U (overload tripping) characteristic U _n characteristic point (n = 0,1, 2 ...) X transverse direction Y longitudinal direction

Claims

claims

1. Control method for triggering an electronic circuit breaker (1),

- in which samples (i _ß, p) a trigger relevant input signal (i) or a variable derived therefrom with a predetermined sampling frequency (f _m) are recorded continuously,

in which a first sum value (i _M i, PM _O ) is formed over a number of acquired samples (i _β , p),

in which a trigger signal (A) is generated when the first sum value (i _M i, PM _O ) fulfills a predetermined first triggering criterion,

in which a second sum value (iM2 _> PMI) is formed via a number of determined first sum values (i _M i, PM _O ), and

- Wherein the trigger signal (A) is also generated when the second sum value (i _M2 , P _MI ) meets a predetermined second triggering criterion.

2. Control method according to claim 1, wherein two successive first sum values (JMI, PMO) are determined from overlapping sequences of the samples ( _iβ , p).

3. Control method according to claim 1 or 2, in which two consecutive second summation values (i _M 2, PMI) are determined from overlap-free sequences of the first summation values (i _M i, PM _O ).

4. Control method according to one of claims 1 to 3, wherein the current intensity (i) of the current flowing through the circuit breaker (1) load current is used as input signal.

5. Control method according to claim 4, wherein the first sum value (i _M i) is determined from a measure (i _B ) for the absolute value of the current intensity (i) of the load current flowing through the circuit breaker (1).

6. Control method according to claim 4, wherein the first sum value (PMO) is determined from a measure (p) for the squared current intensity (i) of the load current flowing through the circuit breaker (1).

7. Control method according to one of claims 1 to 6, wherein the trigger signal (A) is also generated when a single sample (i _ß ) meets a predetermined triggering criterion.

8. Control method according to one of claims 1 to 7, wherein the sampling frequency (f _m ) is selected as an integer multiple of a mains frequency (fw) of an alternating current to be monitored.

9. A control method according to claim 8, wherein the first sum value (PM _O ) is formed over one or more full periods of the alternating current to be monitored.

10. Control method according to one of claims 1 to 9, wherein the first sum value (ΪM _I , PMO) is formed from a number of immediately consecutive samples (i _B , p) and / or wherein the second sum value (i _M2 , P _M O is formed from a number of immediately consecutive first summation values (i _B , p).

11. Electronic circuit breaker (1)

with an insulating housing (2),

- With a switching contact (46) for the reversible contact closure of a load circuit to be monitored (26), - With a release magnet (24) which acts on a trigger mechanism (30) on the switching contact (46), and

- With a triggering electronics (25) for controlling the trigger magnet (24), wherein the triggering electronics (25) is arranged for automatically carrying out the control method according to one of claims 1 to 10.

12. Circuit breaker (1) according to claim 11, wherein the tripping electronics (25) is formed by a microcontroller in which a control method (100) implementing the control method according to one of claims 1 to 10 is implemented by software.