Additional control unit, ventilation arrangement, ventilation system, operating method for an additional control unit, computer program product

Abstract

Additional control device (100) for the local adaptation of a control signal (SK, SKV) to be supplied to a device-external fan (800), comprising: - a supply input (110) to which a fan supply voltage (UV) can be fed; - a supply output (120) which is designed to provide the supplied fan supply voltage (UV) to the device-external fan (800); - a control input (112) which is designed to receive from a device-external control device (900) an actual control signal (SK) to be supplied to the external fan (800), which actual control signal specifies a desired flow rate (SFL) for the fan (800); - a control unit (130) connected to the control input (112) and to the supply input (110) and using the fan supply voltage (UV) for its own power supply, and comprising: - a flow rate determination unit (140) which is designed to detect a power measurement variable (PL) correlating with an actual flow rate (IFL) of the fan (800); - a control signal adaptation unit (150) which is designed to determine a target control signal (SKV) as a function of the received actual control signal (SK) and the detected power measurement variable (PL) and to compare it with the received actual control signal (SK); - a power control unit (160) which is designed to output either the received actual control signal (SK) or the desired control signal (SKV) to the external fan (800) at a control output (122) depending on the comparison result.

Description

[0001] The invention relates to an additional control unit for locally adjusting a control signal to be supplied to an external fan. The invention further relates to a fan, a ventilation system, a method for operating an additional control unit, and a computer program product.

[0002] For the ventilation and exhaust of rooms, especially in apartments or houses, decentralized ventilation systems are used. Each of these systems has one or more fans in each room to be ventilated. Depending on the type of fan, the fans move the supply air and / or exhaust air to ventilate the room in question. Radial fans or axial fans are used as fans.

[0003] From a user perspective, it is desirable to provide a central control unit even in such decentralized ventilation systems with individually operated fans, which, for example, specifies the desired or prescribed airflow rate for the air exchange. This type of control allows the fans to be switched on or off as needed, or their airflow rate or airflow direction can be controlled. With such a central control unit and a multitude of decentralized fans controlled by it, a star-shaped topology is created.

[0004] When conveying supply or exhaust air, it is desirable to achieve a flow rate that is as constant as possible and corresponds to a specified target flow rate. This is relatively easy to achieve under reference conditions, for example, by controlling the fan with a control signal such as a control voltage or a pulse-width modulated control signal to achieve a specific speed. The fan can thus be controlled to achieve a desired flow rate using an experimentally or mathematically determined relationship between a specific fan speed and the flow rate generated at that fan speed.

[0005] In a first alternative, the control unit can supply the same control signal to each fan in the ventilation system. This relatively simple and therefore technically particularly low-complexity control solution has proven sufficient in many applications. In practice, however, this approach is problematic because individual disruptive influences can affect each fan, resulting in a deviation from the reference conditions. For example, wind acting on the outer wall of a house can lead to increased backpressure in a fan operating through this outer wall, which counteracts the airflow that the fan is intended to deliver. As the backpressure increases, the motor driving the fan is no longer able to maintain the specified airflow above a certain operating point, which means that the airflow is reduced.At the same time, completely different pressure conditions may prevail on other exterior walls of the house due to the given wind direction, which do not affect the air flow rate of fans arranged there.

[0006] In a second known control alternative, the control unit supplies a first control signal only to a first subset of fans in the ventilation system, and a second control signal generated specifically for that subset of fans in the ventilation system. The first and second control signals are supplied to the respective subsets of fans simultaneously and are coordinated with one another in such a way that the interaction of a fan in the first subset with a fan in the second subset creates a desired airflow in a respective room. In this case, the first and second control signals are generally synchronized.

[0007] It would therefore be desirable to be able to keep a predetermined flow rate as constant as possible despite changes in the back pressure during fan operation.

[0008] DE 10 2014 211 416 A1, DE 10 2014 201 343 A1, DE 602 10 580 T2, and US 2013 0218347 A1 describe control and regulation devices, particularly for fans. EP 3 182 607 A1 describes a control device that can evaluate a fan status signal.

[0009] Fans with additional pressure sensors, which detect the backpressure acting on the fan, and an associated control device have also been developed, allowing the fan to be adjusted according to the measured backpressure. However, such fans require increased equipment, making them unattractive from a cost perspective and also leading to increased maintenance and repair costs. Such systems have attracted little interest on the market.

[0010] For these reasons, it is desirable to provide an improved way to control a volume flow rate constancy for a single fan in a ventilation system.

[0011] According to a first aspect, the present invention relates to an additional control device for locally adapting a control signal to be supplied to a device-external fan, comprising: - a supply input to which a fan supply voltage can be fed; - a supply output which is designed to provide the supplied fan supply voltage to the device-external fan; - a control input which is designed to receive an actual control signal to be supplied to the external fan from a control device external to the device, which control signal specifies a desired flow rate for the fan; - a control unit connected to the control input and to the supply input, which uses the fan supply voltage for its own power supply, and which comprises: - a flow rate determination unit designed to detect a performance measurement variable correlating with an actual flow rate of the fan; - a control signal adaptation unit which is designed to determine a target control signal as a function of the received actual control signal and the detected power measurement variable and to compare it with the received actual control signal; - a power control unit which is designed to output either the received actual control signal or the target control signal to the external fan at a control output depending on the comparison result.

[0012] The present invention is based on the recognition of the need to control each fan in a ventilation system with a plurality of fans with relatively little equipment expenditure such that the fan delivers a constant airflow, i.e., has a constant actual airflow rate. The invention is based on the solution concept of being able to equip a conventional fan with an additional control unit according to individual requirements. This unit achieves constant airflow rate control for the respective fan with little expenditure and, in particular, without the need for additional sensors. Such a control unit can also be retrofitted after the fan has already been installed and put into operation.

[0013] For this purpose, the additional control unit according to the invention provides a control input configured to receive an actual control signal from an external control unit to be supplied to the external fan, which signal specifies a target air flow rate for the fan. Such an external control unit is typically a central control unit that controls the operation of a plurality of ventilation units.

[0014] Furthermore, the additional control unit according to the invention has a flow rate determination unit which is designed to detect a power measurement variable correlating with an actual flow rate of the fan external to the device.

[0015] With these input variables, the external control unit acts as a central setpoint generator for a control signal. The external control unit can be designed particularly simply and without complicated wiring requirements, especially without connections for a return channel from the fan to the control unit.

[0016] By retrofitting the fan with the additional control unit or by equipping it with the manufacturer's own equipment, individual fan control can be achieved by recording a power measurement value of the individual fan from the additional control unit and, depending on this power measurement value and the actual control signal, determining a target control signal for the fan in question and feeding it to the fan.

[0017] In this way, when a decreasing power measurement is detected, it is possible to adjust the control signal for the fan in question independently of the control of other fans in the system in such a way that the power measurement - and thus the actual flow rate of the fan - is brought back into the target range.

[0018] Through such an optional, individual decentralized control, each fan can be controlled to a constant flow rate, i.e. a constant actual flow rate of the fan, despite different, fan-individual back pressures, without the external central control unit of the ventilation system being used for this multitude of individual control processes.

[0019] Embodiments of the additional control device according to the invention are described below.

[0020] In preferred embodiments, the flow rate determination unit has an ammeter connected in series between the supply input and the supply output, which ammeter is designed to detect an electrical current flowing between the supply input and the supply output as the power measurement variable during operation of the fan. In concrete terms, this can mean that the additional control unit - in addition to the connection to the control line - is also connected between a supply line and a supply connection of the fan, and can thus measure the electrical power consumed by the fan. A power measurement can be carried out at an approximately constant supply voltage by measuring the electrical current flowing through the supply line. The ammeter can be designed, for example, as a current flow sensor.In this way, a performance measurement correlated with the actual fan output can be recorded without relying on an additional sensor. The actual fan output corresponds to the actual volumetric flow rate moved by the fan, which also takes counterpressure into account. This makes it possible, in particular, to retrofit an additional control unit with relatively little installation effort, since the supply line and control line can be interrupted at one point and the additional control unit can be interposed at this point. At this interface, both the performance measurement can be measured – namely at the supply line – and the target control signal can be fed to the fan for control purposes – namely via the control line.In preferred embodiments, the additional control unit is interposed into an existing plug connection for retrofitting, wherein the plug connection previously, i.e. before retrofitting, connected the fan to the supply line and / or the control line.

[0021] The auxiliary control unit is also supplied with power via the fan's supply line. This has the advantage of eliminating the need for an additional connecting cable and reducing installation effort. Due to its functions, the auxiliary control unit has a low power consumption. Although this power consumption of the auxiliary control unit is included in the current measurement and thus in determining the power measurement variable, it can be neglected as a disturbance variable. The power consumption of the auxiliary control unit is approximately 10 times lower than the power consumption of the fan. Furthermore, due to the continuous computing operations performed by the auxiliary control unit, a constant power consumption of the auxiliary control unit can be assumed.Thus, the power consumption of the additional control unit can be removed from the measurement result with relatively little effort, for example by subtracting a constant value from the measurement result.

[0022] In one embodiment, the delivery capacity determination unit additionally comprises a pressure sensor configured to measure, as a performance measurement variable, a pressure signal that correlates with a backpressure counteracting a delivery volume flow of the fan. The control signal adaptation unit is configured to determine the target control signal alone or, if the delivery capacity determination unit, as explained above, comprises an ammeter connected in series between the supply input and the supply output, additionally as a function of the pressure signal as the detected performance measurement variable. Such an embodiment is based on the finding that the backpressure represents the essential disturbance variable in the control of the fan to a target delivery volume flow.By measuring the backpressure using one or more pressure sensors on the fan, this disturbance can be detected and used to determine the airflow rate. Backpressure is the static pressure difference between the side in front of the fan and the side behind the fan and can be caused, for example, by wind acting on a building from outside or by negative pressure acting inside a building.

[0023] In one embodiment, a speed signal from a fan of the external fan is additionally supplied to the airflow determination unit, and the airflow determination unit is designed to unambiguously assign the power measurement variable to a airflow volume using the speed signal, and in which the control signal adaptation unit is designed to additionally determine the target control signal as a function of the speed signal and the measured current as the detected power measurement variable. In such an embodiment, the fan speed, i.e., the speed of the fan's fan, is used for an improved approximate determination of the airflow volume delivered by the fan. If both the power currently consumed by the fan and the current speed are known, a current operating point of the fan can be determined—in particular unambiguously.When determining the air flow rate based solely on the electrical power consumed by the fan, it may be the case that several fan operating points are relevant for a given measured value. For example, a fan at an operating point with low speed and high backpressure may consume the same electrical power as at an operating point with higher speed and lower backpressure. By determining the fan speed using measurement technology, such ambiguity can be reduced, or in particular, eliminated.

[0024] In one embodiment, an additional control unit is provided with a characteristic curve memory containing a plurality of characteristic curve fields of the external fan, each of which indicates a relationship between the measured power variable and the conveyed volume flow, and in which the control signal adaptation unit is designed to determine the target control signal based on at least one characteristic curve field. Using such characteristic curve fields, an associated current conveyed volume flow can be approximately determined for a current operating point of the fan, which is described by the measured power variable. A plurality of characteristic curve fields, for example for different fan types, can be stored and selected in the characteristic curve memory.

[0025] In one embodiment, an additional control unit is provided with a functional module which has at least one mathematical function, wherein the at least one mathematical function describes a dependency between a counterpressure counteracting the delivery volume flow of the fan and the delivery volume flow.

[0026] In one embodiment, the control signal adaptation unit further comprises a parameterization switch configured to set at least one characteristic curve family from a set of characteristic curve families. Using such a parameterization switch, it is advantageously possible to select a device type during installation of the additional control unit that corresponds to the fan on which the additional control unit is installed. This allows an installer to select the device type during assembly. The parameterization switch can be configured as a rotary switch that can be operated, in particular, using a screwdriver or by hand. Selection can be made by moving the rotary switch to a position corresponding to the desired device type. The parameterization switch can also be configured as an arrangement of a pin strip and one or more plug-in bridges, so-called jumpers.In this case, the device type can be selected by a specific arrangement of jumpers on the pin header. Another variant uses a so-called DIP switch (dual in-line package). Using a combination of several of these switches or different switch positions, a large amount of information can be encoded in a small space. This advantageously allows for more settings than, for example, with a rotary switch or jumper.

[0027] In one embodiment, the control signal is designed as a voltage signal or as a pulse-width-modulated signal. In both cases, the control signal specifies a setpoint, in particular a speed, for an internal fan controller and / or for the motor of a fan. In further developments in which the control signal is designed as a voltage signal, a voltage signal proportional to the setpoint describes this relationship. In further developments in which the control signal is designed as a pulse-width-modulated signal, the setpoint is encoded in the form of a pulse width.

[0028] A second aspect of the invention relates to a ventilation arrangement with a fan which has a control signal input for receiving a control signal and a fan which can be controlled by means of the control signal, wherein the ventilation arrangement additionally has an additional control device according to the first aspect of the invention or one of its embodiments, which is connected upstream of the controllable fan or the control signal input, either internally or externally to the fan.

[0029] The ventilation arrangement shares the advantages explained above in connection with the additional control unit.

[0030] Due to the fact that only the actual control signal is converted into the desired control signal to control the fan depending on the measured power value, the additional control unit in such a ventilation system can advantageously be designed as a retrofittable module with suitable connections, for example, for a plug connection, for easy subsequent installation in the control path between the external control unit and a control input of the respective fan. This allows the additional control unit to be retrofitted with relatively little effort.

[0031] In other embodiments of the ventilation system, the additional control unit is already integrated into a fan by the manufacturer. In this case, a housing can even be omitted, allowing the connections to be designed accordingly, especially since the connection to the fan's control input can be established, for example, by soldering, and the additional control unit is already adequately protected by a fan housing.

[0032] A third aspect of the invention relates to a ventilation system comprising: at least one ventilation arrangement according to the second aspect of the invention or one of its embodiments, and a control device which provides the actual control signal to the at least one ventilation arrangement.

[0033] A fourth aspect of the invention relates to an operating method for an additional control device for the local adaptation of a control signal to be supplied to a device-external fan, comprising: - Receiving a fan supply voltage; - Providing the fan supply voltage to the device-external fan; - Receiving an actual control signal to be supplied to the fan, which specifies a target air flow rate for the device-external fan, from a device-external control unit; - Recording a performance measurement value that correlates with the actual air flow rate of the fan; - Determining a target control signal depending on the received actual control signal and the recorded power measurement; - Comparing the target control signal with the actual control signal; - Output of the received actual control signal or the target control signal to the device-external fan depending on the comparison result.

[0034] A fifth aspect of the invention relates to a computer program product containing executable program code for controlling the execution of an operating method by a programmable processor device of an additional control unit.

[0035] Further embodiments of the invention are described below with reference to the accompanying drawings. They show: Fig. 1 an additional control unit in a schematic circuit diagram, Fig. 2 a possible structure of a ventilation arrangement, Fig. 3 a schematic characteristic curve of a characteristic curve field, Fig. 4 a structure of a ventilation system in a building, Fig. 5 shows a further embodiment of a ventilation arrangement, Fig. 6A, Fig. 6B each shows an embodiment of a parameterization switch.

[0036] Fig. 1 shows an additional control unit 100 according to the concept of the invention. The additional control unit 100 has, on an input side 111, a supply input 110 with a positive input terminal 110.1 and a negative input terminal 110.2. The additional control unit 100 further has, on its input side 111, a control input 112. On an output side 121, the additional control unit 100 has, on a supply output 120, a positive output terminal 120.1 and a negative output terminal 120.2. The additional control unit 100 further has, on its output side 121, a control output 122.

[0037] The additional control unit 100 has a connection 110.1, 110.2, 112 arranged on the input side 111, each of which is assigned to a connection 120.1, 120.2, 122 arranged on the output side 121, and can be connected to a fan 800—in particular, one having its own internal fan control 810. The additional control unit 100 can be connected between a supply line 802 and the internal fan control 810 and can thus be advantageously retrofitted to a fan 800 with relatively little effort.

[0038] The auxiliary control unit 100 has a housing 102, which appropriately protects the components of the auxiliary control unit 100 and shields them from environmental influences such as moisture and dust. The housing 102 can be made of plastic or—in particular—rust-proof metal, for example. The connections 110, 112, 120, 122 can be designed as plugs, pole terminals, or similar electrical contacts to enable reliable and relatively simple installation. The connections 110, 112 can be combined to form a three-pin input plug-in module. Analogously, the connections 120, 122 can be combined to form an output plug-in module.

[0039] In embodiments, the terminals 110, 112, 120, 122 can be enclosed by the housing 102, in which case the housing can be opened at least partially in the area of the terminals 110, 112, 120, 122 for assembly purposes. In such embodiments, the area of the terminals 110, 112, 120, 122 is also advantageously protected from environmental influences.

[0040] In this case, a supply voltage UV is provided to the additional control unit 100 via the supply line 802 at the positive input terminal 110.1 and the negative input terminal 110.2, and a control signal SK is provided at the control input 112. The positive input terminal 110.1 is connected to the positive output terminal 120.1, and the negative input terminal 110.2 is connected to the negative output terminal 120.2, such that the supply voltage UV is provided at the output 120 of the additional control unit 100.

[0041] The additional control unit 100 has a control unit 130 connected to the supply input 110 and the control input 112. The control unit 130 has a delivery rate determination unit 140, a control signal adaptation unit 150, and a power control unit 160.

[0042] The flow rate determination unit 140 in this case has an ammeter 141 configured to measure a current IM flowing between the supply input 110 and the supply output 120 in a main line 114. In this case, the measured current IM is used as a power measurement variable PL, which approximately correlates with a flow rate VF of the fan 800.

[0043] The delivery rate determination unit 140 is connected to the control signal adaptation unit 150 so that the power measurement variable PL is transferred to the control signal adaptation unit 150. The purpose of the control signal adaptation unit 150 is to generate a target control signal SKV. Generation occurs as a function of the power measurement variable PL, for example, by generating a control voltage US or a pulse-width modulated signal PWM as a function of the power measurement variable PL. To generate the target control signal SKV, the actual control signal SK can also be multiplied by a variable factor that depends on the power measurement variable PL. In this case, instead of regenerating the target control signal SKV, the actual control signal SK is adapted to determine the target control signal SKV.

[0044] The generation of the target control signal SKV is based on the knowledge that, at a constant supply voltage UV, the measured current IM is proportional to the electrical power PO consumed by the fan 800 at output 120. Using the information about the consumed electrical power PO, an approximate assignment to a volumetric flow rate VF delivered by the fan 800 can be made. A relatively high measured current IM indicates a relatively high volumetric flow rate VF; conversely, a relatively low measured current IM indicates a relatively low measured current IM.

[0045] The relationship between the power measurement variable PL and the flow rate VF can be described using a characteristic curve map KP. The control signal adaptation unit 150 has a characteristic curve memory 152 in which one or more characteristic curve maps KP can be stored and made available as needed.

[0046] The control signal adaptation unit 150 further comprises a parameterization switch 180, via which a characteristic curve field KP can be selected from a set KPG of characteristic curve fields KP. By selecting a characteristic curve field KP, the additional control unit 100 can be adjusted, particularly during its installation, to a specific device type of a fan 800.

[0047] The target control signal SKV is provided via a power control input 160.3 of the power control unit 160. The power control unit 160 transmits the target control signal SKV to the control output 122 via a power control output 160.2. In preferred embodiments, the power control unit 160 is configured to transmit the target control signal SKV to the control output 122 only if it deviates from the actual control signal SK by more than a certain amount. If the deviation is below this amount, only the actual control signal SK, which can be provided to the power control unit 160 via a power control input 160.1, is transmitted to the power control output 160.2 and thus to the control output 122.

[0048] The components of control unit 130 are supplied with electrical energy via main line 114. For this purpose, a supply branch 132 is connected to main line 114 via a branch node 116. Supply branch 132 is connected to both control signal adaptation unit 150 and power control unit 160 for electrical supply. The energy consumption of additional control unit 100 therefore influences the determination of the power measurement variable PL based on the measured current IM. However, the power consumption of additional control unit 100 is low compared to the power consumption of fan 800. Furthermore, the power consumption of additional control unit 100 is relatively constant, which means that it can be computationally removed from the current measurement result with relatively little effort.

[0049] The fan 800 is controlled via the additional control unit 100 by setting the desired control signal SKV, depending on the power consumption of the fan 800, i.e. the electrical power PO that is requested from the fan 800 via the output 120 of the additional control unit 100.

[0050] In preferred embodiments, the airflow rate determination unit 140 can have a sensor input 142. Alternatively or in addition to the current meter 141 of the airflow rate determination unit 140, measured values for determining the power measurement variable PL can be recorded via this sensor input 142. In particular, a rotational speed N of a fan 800 can be provided via the sensor input 142. For this purpose, the sensor input 142 can be connected to a position sensor or rotary encoder (not shown here). In embodiments, it is possible to read the rotational speed N directly from a motor of the fan.

[0051] Also, a - a in Fig. 2. The pressure sensor 402 acting on the fan 800 can be measured using the pressure sensor 402. Using the back pressure PG, the volumetric flow rate VF can be better approximated, particularly since the estimation of the volumetric flow rate is not based solely on the electrical output power PO.

[0052] A possible structure of a ventilation arrangement 600 with a fan 800 and an additional control unit 100 is shown in Fig. 2. The fan 800 has a fan housing 806, which is formed in the present case as a pipe section whose diameter D approximately corresponds to the diameter of the ventilation pipe to which the fan 800 is connected.

[0053] A fan 804 is arranged within the fan housing 806, which is arranged coaxially with the tubular ventilation housing 806. The fan also has an internal control 810, which supplies and controls a motor 805 of the fan 804 via an electrical fan line 812. The motor 805 is preferably designed as an EC motor. The internal fan control 810 is not directly connected to a supply line 802; instead, the additional control unit 100 is interposed between the supply line 802 and the internal fan control 810. In advantageous developments, the additional control unit 100 is designed such that it allows easy retrofitting, i.e., subsequent installation in the fan 800 with relatively little effort.Such retrofitting is achieved in particular by standardized plug connections at the inputs 110, 112 and at the outputs 120, 122, which are particularly compatible with an already existing plug connection between the supply line 802 and the internal control 810.

[0054] In preferred embodiments of the invention, it is also possible for the fan 800 not to have an internal control 810, and for the additional control unit 100 to thus directly control the fan 804 by connecting the output 120 directly to the fan line 812.

[0055] Fig. 3 schematically shows a characteristic curve KL of a characteristic curve family KP. The characteristic curve KL describes the relationship between a flow rate VF and a power measurement PL at a constant fan speed N. Under reference conditions, i.e. in particular when a back pressure PG acting against the flow rate VF is zero, the power measurement PL is also zero. In this case, the flow rate VF assumes a maximum reference value VFREF at a reference operating point APREF. If the back pressure PG increases, the power consumption of the fan 800 increases at the same time. This means that the electrical power PO required to keep the fan 800 at the constant fan speed N with increasing back pressure PG increases. Consequently, the measured current IM and thus the power measurement PL also increase. A first power measurement PL1 is measured at a first operating point AP1 shown here.According to the characteristic curve KL, the flow rate is VF1, which is therefore smaller than VFREF. Thus, the flow rate VF can be approximately determined using the power measurement variable PL.

[0056] Fig. Figure 4 schematically shows the structure of a ventilation system 1000 in a building 1200. The building 1200 has four rooms 1201, 1202, 1203, 1204. For example, each room 1201-1204 is assigned a ventilation arrangement 600a-d, each with a fan 800a-d; this assignment is merely exemplary—it is equally possible, for example, for multiple fans to be assigned to a room.

[0057] The four ventilation arrangements 600a-d each have an additional control unit 100a-d according to the concept of the invention. The four additional control units 100a-d are connected to an external control unit 900. The control of the fans 800a-d by the respectively assigned additional control unit 100a-d ensures that a predefined volume flow VFa-d is always delivered - in particular, regardless of a backpressure PG acting on the respective fan 800a-d. This control is thus advantageously designed in a decentralized manner, since the external control unit 900 only specifies a target state for each individual fan 800a-d - in the simplest case, this can be the "on" or "off" state, or a control signal SK determined for a specific target delivery volume VFSOLL. The control of each individual fan is handled by the additional control unit 100a-d assigned to this fan 800a-d.Thus, each fan 800a-d is controlled according to the ambient conditions prevailing at that fan, in particular according to the back pressure PG prevailing at the respective fan 800a-d.

[0058] In the present case, a first fan 800a is arranged in the outer wall of the building 1200 between the environment U and the first room 1201. The first fan 800a has an additional control unit 100a, which is connected to the central control unit 900 via a first supply line 802a.

[0059] Due to the weather conditions, a wind distribution WV exists that acts on building 1200 and is more pronounced in the upper area than in the lower, ground-level area. This results in a higher second backpressure PG2 acting on the first fan 800a located higher up than a higher first backpressure PG1 acting on a third fan 800c located lower down.

[0060] According to the concept of the invention, control is carried out decentrally by the respective additional control unit 100a, 100c. In order to maintain a constant first fan speed Na of the first fan 800a, a higher electrical output power POa of the first fan 800a is necessary due to the backpressure PG2. This increased power requirement is measured by the air flow rate determination unit 140 (not shown in detail here). Based on the measurement, the air flow rate determination unit generates a first target control signal SKVa, which in turn is sent to a first power control unit 150a. The first power control unit 150a sends the first target control signal SKVa to the first fan 800a in order to increase the air flow rate of the fan 800a.This adjustment process is repeated in the sense of a control loop until a first electrical output power POa of the first fan 800a is measured, which corresponds to the first desired flow rate VFa.

[0061] If it is now assumed that the first air flow volume VFa and the third air flow volume VFc have a setpoint VFSOLL of the same amount and both air volume flows VFa, VFc are led out of the building 1200 - for example as part of a pendulum ventilation process - a first setpoint control signal SKVa of the first fan 800a must be set higher than a third setpoint control signal SKVc of the third fan 800c due to the higher back pressure PG2.

[0062] Fig. Figure 5 shows a further development of a fan 800' with a fan housing 806' that does not have an internal fan controller 810. Instead, an additional control unit 100' is directly connected to a motor 805' of a fan 804' via a fan line 812'. In this further development, the additional control unit 100' directly controls the fan 804' and thus assumes the function of the internal fan controller 810.

[0063] Fig. 6A and Fig. 6B each show advantageous further developments of a parameterization switch 180, 180'. Fig. 6A shows a parameterization switch 180 with a selector switch 181. Using the parameterization switch 180, a device- or type-specific setting of one or more suitable characteristic curve fields KP can be made, for example, using a screwdriver via a selector switch 181 on the parameterization switch 180. Depending on the rotational position of the selector switch 181, a specific model of the fan 800 can thus be selected. The parameterization switch 180 can be arranged such that it is accessible from the outside of a housing 102 (not shown here). Alternatively, it can be integrated into the housing 102, so that the housing 102 must be opened for parameterization, particularly during installation of the additional control unit 100. Using the parameterization switch 180, the additional control unit 100 can be adapted to a specific model of the fan 800 with relatively little effort, particularly during retrofitting.

[0064] As an alternative to a rotary switch, a parameter switch 180' - this is in Fig. 6B - also have an arrangement of one or more jumpers 182, so-called jumpers, which are plugged onto an electronic pin strip 183. In this way, depending on the arrangement of the jumpers 182, one or more characteristic curve fields KP can be selected for a specific model of the fan 800. By means of one or more jumpers 182, an additional control unit 100 can advantageously be adjusted to a relatively large number of variants. List of reference symbols 100, 100a-d, additional control unit 100' 102 housing 110 Supply input 110.1 Positive input terminal 110.2 Negative input terminal 111 Entrance page 112 Control input 114 Main line 116 branch nodes 120 supply output 120.1 Positive output terminal 120.2 Negative output terminal 121 Exit side 122 Control output 130 Control unit 132 supply branch 140 Capacity Determination Unit 141 ammeters 142 Sensor input 150 Control signal adaptation unit 152 characteristic curve memories 160 power control unit 160.1 Power control input 160.2 Power control output 160.3 Power control input 180, 180' parameter switch 181 selector switch 182 jumper 183 pin header 400 sensors 402 pressure sensor 600, 600a-d, ventilation arrangement 600' 700 Power supply 710 Higher-level control 800, 800a-d, fan 800' 802 supply line 803 control line 804, 804' fan 805, 805' engine 806, 806' fan housing 810 Internal fan control 812, 812' fan line 814 supply input 815 Control input 900 Central Control 1000 ventilation system D Diameter of the ventilation housing IM Measured current KP characteristic field KPG set of characteristic curves N, Na, Nc fan speed PF Fan capacity PL Performance parameter, performance parameter correlating with the fan's air flow rate PO, POa, POc Electrical output power, power consumed by the fan PG1, PG2 First, second back pressure PP pressure signal SK actual control signal SKV, SKVa-d target control signal U environment US control voltage UV supply voltage VF, flow rate VFa-d VFSOLL Displacement flow setpoint WV wind distribution

Claims

[1] Additional control device (100) for the local adaptation of a control signal (SK, SKV) to be supplied to a device-external fan (800), comprising: - a supply input (110) to which a fan supply voltage (UV) can be fed; - a supply output (120) which is designed to provide the supplied fan supply voltage (UV) to the device-external fan (800); - a control input (112) which is designed to receive an actual control signal (SK) to be supplied to the external fan (800) from a control device (900) external to the device, which control signal specifies a desired flow rate (SFL) for the fan (800); - a control unit (130) connected to the control input (112) and to the supply input (110) and using the fan supply voltage (UV) for its own power supply, and comprising: - a flow rate determination unit (140) which is designed to detect a power measurement variable (PL) correlating with an actual flow rate (IFL) of the fan (800); - a control signal adaptation unit (150) which is designed to determine a target control signal (SKV) as a function of the received actual control signal (SK) and the detected power measurement variable (PL) and to compare it with the received actual control signal (SK); - a power control unit (160) which is designed to output either the received actual control signal (SK) or the desired control signal (SKV) to the external fan (800) at a control output (122) depending on the comparison result. [2] Additional control device (100) according to claim 1, characterized byin that the delivery capacity determination unit (140) has an ammeter (141) connected in series between the supply input (110) and the supply output (120), which ammeter is designed to detect an electrical current (IM) flowing between the supply input (110) and the supply output (120) as the power measurement variable (PL) during operation of the fan (800). [3] Additional control device (100) according to claim 1 or 2, in which - the delivery capacity determination unit (140) additionally comprises a pressure sensor (402) which is designed to measure a pressure signal (PP) as a performance measurement variable (PL), which correlates with a counterpressure (PG) counteracting a delivery volume flow (VF) of the fan (800), and in which - the control signal adaptation unit (150) is designed to determine the desired control signal (SKV) alone or, in the case of the dependency of claim 2, additionally as a function of the pressure signal (PP) as the detected power measurement variable (PL). [4] Additional control device (100) according to at least one of claims 1 to 3, in which - the delivery capacity determination unit (140) is additionally supplied with a speed signal (PN) of a fan (804) of the external fan (800), and the delivery capacity determination unit (140) is designed to unambiguously assign the power measurement variable (PL) to a delivery volume flow (VF) using the speed signal (PN), and in which - the control signal adaptation unit (150) is designed to determine the target control signal (SKV) additionally as a function of the speed signal (PN) and the measured current (IM) as the detected power measurement variable (PL). [5] Additional control device (100) according to at least one of the preceding claims, - with a characteristic curve memory (152) which contains a plurality of characteristic curve fields (KP) of the external fan (800), each of which indicates a relationship between the power measurement variable (PL) and the conveying volume flow (VF), and in which - the control signal adaptation unit (150) is designed to determine the desired control signal (SKV) on the basis of at least one characteristic curve field (KP). [6] Additional control device (100) according to at least one of the preceding claims, - with a functional module having at least one mathematical function, wherein the at least one mathematical function describes a relationship between a counterpressure counteracting the flow rate of the fan and the flow rate. [7] Additional control device (100) according to claim 5, characterized bythat the control signal adaptation unit (150) further comprises a parameterization switch (180) which is designed to set at least one characteristic curve field (KP) from a totality of characteristic curve fields (KPG). [8] Additional control device (100) according to one of the preceding claims, characterized by that the control signal (SK, SKV) is designed as a voltage signal (US) or as a pulse width modulated signal (PWM). [9] Ventilation arrangement (600) with - a fan (800) having a control signal input (815) for receiving a control signal (SK, SKV) and a fan (804) controllable by means of the control signal, wherein - the ventilation arrangement (600) additionally comprises an additional control device (100) according to one of claims 1 to 8, which is connected upstream of the controllable fan (800) or the control signal input (815) internally or externally to the fan. [10] Ventilation system (1000), comprising: - at least one ventilation arrangement according to claim 9, and - a control device (900) which provides the actual control signal (SK) to the at least one ventilation arrangement. [11] Operating method for an additional control device (100) for the local adaptation of a control signal (SK, SKV) to be supplied to a device-external fan (800), comprising: - Receiving a fan supply voltage (UV); - Providing the fan supply voltage (UV) to the device-external fan (800); - receiving an actual control signal (SK) to be supplied to the fan (800), which specifies a target flow rate (SFL) for the device-external fan (800), from a device-external control device (900); - Recording a performance measurement variable (PL) correlating with an actual air flow rate (IFL) of the fan (800); - Determining a target control signal (SKV) depending on the received actual control signal (SK) and the recorded power measurement variable (PL); - Comparing the target control signal (SKV) with the actual control signal (SK); - Output of the received actual control signal (SK) or the target control signal (SKV) to the device-external fan (800) depending on the comparison result. [12] Computer program product containing executable program code for controlling the execution of a method according to claim 11 by a programmable processor device of the additional control unit.

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