Protective circuit for an appliance circuit breaker or circuit breaker and method therefor

Abstract

The invention relates to a protective circuit (1) for an appliance circuit breaker or circuit breaker, having: an actively controllable component (B1) which can be controlled in a linear range; - at least one measuring device (SP, SU, Si, SUin, SUout) for determining a power which is converted in the actively controllable component (B1); - a processing unit (uC); - wherein an energy equivalent can be determined on the basis of the determined power and a time between two measurements, - wherein temporally separate energy equivalents are summarised by the processing unit (uC); - wherein at least two time-related limit values (Gt1, Gt2,...Gtn) are provided;, - wherein, when if a limit value (Gt1, Gt2,...Gtn) is reached and / or exceeded by an energy equivalent or the combined energy equivalents in the time assigned to a limit value (Gt1, Gt2,...Gtn), the active controllable component (B1) is actuated by the processing unit (uC) so that the current flow through. The invention also relates to a method.

Description

[0001] -1- Protective Circuit for a Device or Circuit Breaker and Method for Its Use Background In many areas of electrical installations and devices, current-limiting or current-disconnecting elements are found. One purpose of such elements can be, for example, to protect parallel-installed electrical devices from voltage dips, such as those that could occur if a load draws more current. Such situations can arise, for example, in the event of a short circuit, or when large capacitive loads need to be charged, or more generally, when a new load is added. If no protective measure is taken, unexpected disturbances, malfunctions, or even damage can occur, not only in the affected device itself but also in other loads connected to the same power supply network.Electronic circuit breakers or power circuit breakers are frequently used to limit or disconnect the current to the power-consuming device. These electronic circuit breakers or power circuit breakers generally use an active component that typically operates in linear mode. In current-limiting mode, electrical power is converted into thermal power within the active component. If the converted power exceeds a certain threshold, permanent damage to the active component can occur. Therefore, manufacturers of active components provide corresponding characteristic curves in their datasheets; in the case of MOSFETs, this is the so-called SOA (Safe Operating Area) characteristic. These characteristic curves are included in a worst-case analysis and used for the design process to guarantee the safe operation of the component.For worst-case analysis, the maximum (rated) operating voltage is generally used, since in the event of a short circuit, (almost) the entire operating voltage is applied to the active component. Depending on the limited current, this determines the maximum time the component may operate linearly. While this approach ensures safe operation, it restricts the characteristics during normal operation. In particular, charging larger capacitive loads or, more generally, operation in non-constant states becomes more difficult or impossible. Objective: Based on this, an object of the invention is to provide an improvement that allows safe operation while also limiting the characteristics of normal operation to a lesser extent. Summary of the Invention: The object is achieved by a protective circuit for a device or power circuit breaker according to claim 1 or 2.A method according to claim 13. Further advantageous embodiments are the subject of the dependent claims, the description, and the figures. Summary of Figures 3: The invention is explained in more detail below with reference to a drawing and exemplary embodiments. The drawing is a schematic representation and not to scale. The drawing does not limit the invention in any way. It shows: Fig. 1 views of a circuit breaker according to embodiments of the invention, Fig. 2 an exemplary flowchart of process steps according to embodiments of the invention, Fig. 3 another exemplary flowchart of process steps according to embodiments of the invention, and Fig. 4 an exemplary SOA diagram. Detailed description of the invention: The invention will be described in more detail below with reference to the figures.It should be noted that different aspects are described, each of which can be used individually or in combination. This means that each aspect can be used with different embodiments of the invention, unless explicitly presented as a pure alternative. Furthermore, for the sake of simplicity, reference is generally made to only one entity at a time. Unless explicitly stated otherwise, the invention may also include several of the entities in question. Therefore, the use of the words "a," "an," and "one" should only be understood as indicating that at least one entity is used in a simple embodiment. Values ​​given are generally not to be understood as exact values, but include a tolerance of + / - 1% to + / - 10%.-4- Where standards, specifications or the like are mentioned in this application, reference is always made to at least those standards, specifications or the like applicable on the filing date. That is, if a standard / specification etc. is updated or replaced by a successor, the invention is also applicable thereto. Unless otherwise stated, circuit breakers are in particular compliant with DIN EN IEC 60934 VDE 0642:2020-11. In one embodiment of the invention, a protective circuit 1 for a device or power circuit breaker is provided. Without claiming to be exhaustive, this protective circuit 1 comprises an active controllable component B. 1 The protection circuit 1 includes a component that can be controlled within a linear range. Furthermore, it comprises at least one measuring device (SP, SU, Si, SUin, SUout) for determining the power dissipated in the actively controllable component B1, and a processing unit (uC). "Determine" is to be understood broadly and can include direct measurement, indirect measurement, reading from a characteristic map, calculation, etc., and possibly further processing steps. A measurement can be taken at the actively controllable component B1. 1 The changes can be made to the component itself or to other elements. The only essential point is that the final result is a statement about the power output in the actively controllable component B. 1 is provided. Based on the specified power(s) and a time between two measurements, an energy equivalent can be determined, whereby the processing unit uC aggregates time-separated energy equivalents. Without loss of generality, aggregation includes both the evaluation of individual values ​​and the further processing of previous values. For example, further processing may involve the digital implementation of transmission elements. -5- For further processing, at least two time-related limit values ​​G are required. t1 , G t2 , … G tn provided for, whereby upon reaching and / or exceeding a limit value Gt1, Gt2, … Gtn by an energy equivalent or the combined energy equivalents in the limit value G t1 , G t2, … Gtn-assigned time, the active controllable component B1 is controlled by the processing unit uC such that the current flow through the active controllable component B1 is reduced or prevented. In one embodiment of the invention, the actively controllable component B1 is a semiconductor device, in particular a power semiconductor. For example, the actively controllable component B1 is selected from a group comprising a field-effect transistor, in particular a MOSFET, or an IGBT transistor. That is, the invention is applicable to a wide range of devices. In another embodiment of the invention, the determination of energy equivalents is only initiated when a limit value of a quantity previously measured or calculated for determining power is exceeded. This can reduce the computational effort. This also allows, for example,To avoid erroneous shutdowns, which can otherwise occur depending on the implementation, e.g., through continuous summation / integration. According to a further embodiment of the invention, the determination of energy equivalents can be aborted if a threshold value of a quantity previously measured or calculated for determining power is undershot. This reduces the computational effort. In yet another embodiment of the invention, a predetermined value is subtracted from the total energy equivalents, particularly if a threshold value of a quantity previously measured or calculated for determining power or an energy equivalent is undershot. This allows, for example, consideration of the fact that the actively controllable component B... 1 after a power input, it cools down again. A thermal resistance, for example, can be taken into account accordingly. If, for example, another "monitoring event" occurs after a short time, this can also take the previous "monitoring event" into account, depending on the elapsed time, since the total energy equivalents may not yet have returned to 0. -6- According to yet another embodiment of the invention, energy equivalents are determined, in particular, periodically. This allows a continuous safety function to be provided. It also facilitates the use of transfer elements and thus enables low computational effort. In yet another embodiment of the invention, the at least one measuring device S P , S U , S i , S Uin , S Uoutto determine power, ^ a current measuring device S I , and at least one voltage measuring device S U to determine a voltage across the actively controllable component B1, or ^ a power measuring device S PHowever, other embodiments are not excluded. Without limiting the generality of the invention, in a further embodiment, the voltage across the actively controllable component B1 is determined by measuring the difference between the voltage at the input Uin of the actively controllable component B1 and at the output Uout of the actively controllable component B1. Furthermore, in embodiments of the invention, the processing unit uC may comprise a microcontroller, a microprocessor, an FPGA, an ASIC, a DSP, or the like. Likewise, the protection circuit 1 according to the invention may also be part of a device or power circuit breaker. Exemplary methods are described below with reference to Figures 2 and 3. For example, an initialization step 50 may be provided in which, for example, counter variables are set to a predetermined value, e.g.,to a total energy equivalent E(t=0)=0. -7- An exemplary method according to the invention for a protective circuit 1 according to the invention for a device or power circuit breaker with an actively controllable component B1, which is controllable in a linear range, comprises a step of determining a power 100, 300 by the actively controllable component B1. For example, this step can be implemented as a single power determination step or as a distributed step. For example, a voltage U can be determined in step 100 and a current I in step 300. Only when both values ​​are available can a power be determined. Based on the determined power and a time Δt between two measurements, an energy equivalent can be determined, where time-separated energy equivalents in one step 400, e.g. E(t)=E(t‒1)+ E Mess= E(t‐1)+ U*I* Δt, summarized. As previously described, at least two time-related limit values ​​Gt1, Gt2, … Gtn are provided, whereby upon reaching and / or exceeding a limit value G 500 t1 , G t2 , … G tn by an energy equivalent or the combined energy equivalents in a limit value Gt1, G t2 , … G tnDuring the assigned time t1, t2 … tn, the active controllable component B1 is controlled such that the current flow through the active controllable component B1 is reduced or interrupted. In embodiments of the invention, it may be provided that the determination of energy equivalents is only initiated when a limit value of a quantity previously measured or calculated for determining power is exceeded. Likewise, in embodiments of the invention, it may also be provided that the determination of energy equivalents is terminated when a limit value of a quantity previously measured or calculated for determining power is not reached. Furthermore, it may also be provided that when a limit value of a quantity previously measured or calculated for determining power or of an energy equivalent is not reached, a predetermined value is subtracted from the total energy equivalents.Alternatively, a reset of the total energy equivalents -8- can also be provided, e.g., if the time interval between two measurements is so long that the predetermined value to be subtracted would be greater than or equal to the total energy equivalent. As mentioned previously, energy equivalents can be determined periodically. For this purpose, the loop back after step 500 can be used, for example. According to one embodiment of the invention, a step includes determining a power: Determining a voltage across the actively controllable component B1, where the difference of the voltage at input U. in of the actively controllable component B1 and at output U outThe active controllable component B1 is determined. Without limiting the generality, it can be provided that, for example, values ​​from different SOA characteristic curves, e.g., for different times (e.g., 100 µs, 1 ms, 10 ms, 100 ms), are used for the determination. From the knowledge of two limit values ​​from the corresponding characteristic curves, limit values ​​for other times can be determined / approximated. With the invention, it is now possible to protect parallel-connected devices from unwanted voltage dips by limiting the current in the load section to be protected, while at the same time the range of the permissible current can be used more effectively by dynamically adjusting the control / switching condition. Instead of determining a time based on given data, it is advantageous to look at individual points of the characteristic curve, e.g., points of the same voltage at different times.Each point then provides a relationship for current, voltage, and time. The product yields the permissible energy at a time T. To obtain energy as a function of time E(t), an approximation between points of the SOA characteristic curve – see, for example, Figure 4 – can be performed. The time reference value T0 is relevant for this. Since the SOA characteristic curve is only valid for linear operation, the times mentioned in it are also considered from the beginning of linear operation. The time reference value T0 is used for this purpose. As described below, exceeding a limit value can be used to define T0. This approximation can be either a step function between the SOA points or an approximation between the known support points. It is possible to calculate the energy at the linearly operated component(s).In the example shown, input voltage ^^^^, output voltage ^^^௨௧, and current i (steps 100, 300) can be measured, multiplied by their sampling interval ^^^, and then accumulated with the previous value (step 400). It can be stipulated that accumulation only occurs if linear operation is present, e.g., if the voltage in step 200 exceeds a certain limit, for example, only if the difference between ^^ is present when the device is switched on. ^^ and ^^ ^௨௧ a limit U X exceeds. If the limit is exceeded, this can simultaneously serve as a time reference value ^^ ^ be used. for ^^^^௨௧ െ ^^^^^ ^ ^^௫ ^^ெைௌ^^^^^^^ ൌ ^^ெைௌ ^^^^ െ 1^ ∙ ^^^^ for ^^^^௨௧ െ ^^^^^ ^ ^^௫ ‐10‐ The observed energy of the component can be compared with the permissible energy per unit of time relative to the reference value T0. If the observed energy is greater than or equal to the permissible energy, linear operation should be abandoned. In the example, this can be achieved by switching off the channel or changing the limiting current in step 600. If the current is changed, monitoring (not shown) can be performed such that if the actual current falls below the limited current, an energy decrement is carried out or the current limit is reset, analogous to step 275. This dynamic energy monitoring allows both supply voltage and load variations to be integrated into the component protection routines.

[0002] -11- Designation list 1 Protection circuit B 1 Active controllable component SP, SU, Si, SUin, SUout Measuring device uC Processing unit Gt1, Gt2, … Gtn Time-related limit values ​​RShunt, RLast Resistance

Claims

Claims 1. Protection circuit (1) comprising a device or power circuit breaker, ^ an active controllable component (B1) which is controllable in a linear range, ^ at least one measuring device (S P , S U , S i , S Uin , S Uout ) to determine a power output converted in the actively controllable component (B1), ^ a processing unit (uC), ^ wherein an energy equivalent can be determined based on the determined power output and a time between two measurements, ^ wherein time-separated energy equivalents are aggregated by the processing unit (uC), ^ wherein at least two time-related limit values ​​(G t1 , G t2 , … G tn ) are provided for, ^ wherein upon reaching and / or exceeding a limit value (G) t1 , G t2 , … G tn ) by an energy equivalent or the combined energy equivalents in a limit value (Gt1 , G t2 , … G tn) the active controllable component (B1) is controlled by the processing unit (uC) during the assigned time such that the current flow through the active controllable component (B1) is reduced or prevented.

2. Protection circuit (1) according to claim 1, characterized in that the active controllable component (B1) is a semiconductor device.

3. Protection circuit (1) according to claim 1 or 2, characterized in that the active controllable component (B1) is a power semiconductor.

4. Protection circuit (1) according to any one of the preceding claims, characterized in that the active controllable component (B1) is selected from a group comprising a field-effect transistor, in particular a MOSFET, or an IGBT transistor. 5.

6. Protective circuit (1) according to one of the preceding claims, characterized in that the determination of energy equivalents is only initiated when a limit value of a quantity previously measured or calculated for determining power is exceeded.

7. Protective circuit (1) according to claim 5, characterized in that the determination of energy equivalents is terminated when a limit value of a quantity previously measured or calculated for determining power is undershot.

8. Protective circuit (1) according to one of the preceding claims, characterized in that, in particular, when a limit value of a quantity previously measured or calculated for determining power or of an energy equivalent is undershot, a predetermined value is subtracted from the total energy equivalents.Protection circuit (1) according to one of the preceding claims, characterized in that energy equivalents are determined periodically.

9. Protection circuit (1) according to one of the preceding claims, characterized in that the at least one measuring device (p. P , S U , S i , S Uin , S Uout ) to determine power, ^ a current measuring device (S I ), and at least one voltage measuring device (S U ) to determine a voltage across the actively controllable component (B1), or ^ a power measuring device (S P ) exhibits.

10. Protection circuit (1) according to one of the preceding claims, characterized in that the voltage across the actively controllable component (B1) is determined by measuring the difference in voltage at the input (U in ) of the actively controllable component (B1) and at the output (U out) of the actively controllable component (B1).

11. Protection circuit (1) according to one of the preceding claims, characterized in that the processing unit (uC) comprises a microcontroller.

12. Device or power circuit breaker comprising a protection circuit (1) according to one of the preceding claims.

13. Method for a protection circuit (1) for a device or power circuit breaker with an actively controllable component (B1) which is controllable in a linear range, comprising the steps ^ determining a power (100, 300) that is converted in the actively controllable component (B1), ^ wherein an energy equivalent is determined based on the determined power and a time between two measurements, ^ wherein time-separated energy equivalents (400) are aggregated, ^ wherein at least two time-related limit values ​​(G) t1 , G t2 , … G tn) are provided for, ^ wherein upon reaching and / or exceeding (500) a limit value (G) t1 , G t2 , … G tn ) by an energy equivalent or the combined energy equivalents in a limit value (G t1 , G t2 , … G tn) the active controllable component (B1) is controlled such that the current flow through the active controllable component (B1) is reduced or interrupted (600) within the assigned time.

14. Method according to claim 13, characterized in that the determination of energy equivalents is only initiated when a limit value (200) of a quantity previously measured or calculated for the determination of power is exceeded.

15. Method according to claim 14, characterized in that the determination of energy equivalents is terminated (250) when a limit value of a quantity previously measured or calculated for the determination of power is not reached. 16.A method according to any one of the preceding claims 13 to 15, characterized in that, if a limit value of a quantity or energy equivalent previously measured or calculated for determining power is undershot, a predetermined value is subtracted from the total energy equivalents (275).

17. A method according to any one of the preceding claims 13 to 16, characterized in that the determination of energy equivalents is carried out periodically.

18. A method according to any one of the preceding claims 13 to 17, characterized in that the step of determining power comprises: Determining a voltage across the actively controllable component (B1), wherein the difference in voltage at the input (U. in ) of the actively controllable component (B1) and at the output (U out ) of the actively controllable component (B1) is determined.

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