Field of the invention

[0001] The present invention concerns an actuator system, a method and a computer program, in particular for Heating, Ventilation and Air Conditioning (HVAC), fire protection or room protection applications. Description of related art

[0002] In order to move a damper in a ventilating system or a valve in a water conducting system, relatively weak motors have to activate control elements which have large areas or large volumes. Precise and stable adjustment is possible with a pronounced step-down ratio. In order to rotate a damper or rotate a ball valve through an acute, right-angled or oblique angle, numerous rotations of the drive shaft of the electric motor are necessary. If a valve is displaced linearly, the same applies to a relatively small displacement.

[0003] Both in the case of a gas volume flow and in the case of a liquid volume flow it is highly important that when there is no power the damper and/or the valve can be returned to a predetermined safety position, generally the closed position.

[0004] This has conventionally been done with a return spring which is spring loaded by the electric motor when the shut-off element is activated. The shut-off element can be for example a damper or a valve. When there is a voltage drop, likewise of a predetermined magnitude, which is detected by a corresponding sensor, or no power at all, the electrical power feed of the electric motor is switched off. As a result, the force opposing the tensioned spring is eliminated and the return action can occur virtually immediately. However, these spring systems which have been used for a long time always have the disadvantage that they give rise to increased wear of the mechanics and that the spring loses its tension over time. [0005] Therefore, EP2020073 discloses an electrical solution for a safety drive. In this solution, a supercapacitor stores the electrical energy necessary for driving the damper in a predetermined safety position, when a power breakdown is detected. Problematic with this solution is that the storage capacity of the supercapacitor decreases with the years of usage and that at a certain point, the stored energy is not sufficient any more to fulfil the safety drive requirements.

[0006] The end of life of the supercapacitor can be estimated on the basis of the rest capacity. Unfortunately, this end of life estimation is not very exact and very often for safety reasons much earlier than the real end of life of the supercapacitor.

Brief summary of the invention

[0007] It is object of the invention to find an actuator system which overcomes the problems of the state of the art. [0008] According to the invention, the object is solved by an actuator system, a method, an apparatus and a computer program according to the independent claims.

[0009] Since the real energy consumption of the safety actuation of the actuator depends strongly on the connected fluid control device, the storage management information depends also on the value indicating the energy consumption for the predetermined safety actuation. Therefore including this value indicating the energy consumption is significantly more precise than the state of the art. This allows to use the safety means much longer and reduces malfunctions due to end of lifetime prediction of power storages.

[0010] The dependent claims refer to further advantageous

embodiments of the invention.

Brief Description of the Drawings [0011] The invention will be better understood with the aid of the description of an embodiment given by way of example and illustrated by the figures, in which:

Fig. 1 shows a schematic exemplary embodiment of an actuator system.

Detailed Description of possible embodiments of the Invention

[0012] Fig. 1 shows an exemplary embodiment of an actuator system 1.

[0013] The actuator system 1 comprises a power input 10, an actuator 20, a safety means 30, a storage management means 40 and an output means 50.

[0014] The power input 10 is configured such that it can be selectively connected to a power source (not shown) so that the power source can supply a voltage to the actuator system 1 , thereby powering the actuator system 1. The power input 10 could be for example a socket or a plug. The power source may supply any level of voltage to the power input 10; for example the power source may be configured to supply 230 VAC, or 1 10 VAC, or 24 VAC/DC or 72 VDC. In one embodiment the power input 10 further comprises a power converter for converting voltage which is supplied by the power source to the power input 10, into an intermediate circuit voltage. Most preferably the intermediate circuit voltage is a different voltage to the voltage which is supplied by the power source to the power input 10; in other words the power converter converts the voltage which is supplied by the power source to the power input 10, into a different, intermediate circuit, voltage. The intermediate circuit voltage may be, for example, a voltage which is lower than 50 VDC, or a voltage which is lower than 30 VDC, or may be 24 VDC, or may be 12 VDC, if the input voltage is different than the intermediate circuit voltage. For example the power source may supply a voltage of 50 VDC to the power input 10, and the power converter may convert that voltage to an intermediate circuit voltage which is lower than 50 VDC; in yet a further example the power source may supply a voltage of 30 VDC to the power input 10, and the power converter may convert that voltage to an

intermediate circuit voltage which is lower than 30 VDC. In yet a further example the intermediate circuit voltage is equal to the voltage which is supplied by the power source to the power input 10.

[0015] The actuator 20 is configured to be connected to a fluid volume control device 2 and to actuate the fluid volume control device 2 for controlling a fluid volume. The fluid could be a gas or a liquid. For example, the fluid could be air; the use of air as a fluid is common for HVAC

applications. In another example the fluid could be water or water glycol mixtures; the use of water as a fluid is common for many heating and cooling applications. The fluid volume control device 2 could be a shut-off element, e.g. a damper or a valve. When the fluid volume control device 2 is actuated then the fluid volume control device 2 undergoes a translational and/or rotational movement and/or a part of the fluid volume control device 2 undergoes a translational and/or rotational movement.

[0016] In the embodiment shown in Fig. 1 , the actuator 20 comprises an electric motor 22 and an electronic control unit (ECU) 21 for controlling the electric motor 22. The ECU 21 is connected to the power input 10; the power input 10 receives power from a power source which is connected to the power input 10, and uses that received power to generate a drive current/voltage; the power input 10 passes the generated drive

current/voltage to the ECU 21 which in turn drives the electric motor 22. The ECU 21 is preferably an Application Specific Integrated Circuit (ASIC). The electric motor is preferably a brushless DC motor. Preferably, the actuator 20 further comprises a gear transmission 23 with a gear reduction for increasing the force or torque of the motor on the fluid volume control device 2. However, it should be understood that the invention is not limited to requiring that the actuator 20 be implemented exactly as shown in Fig. 1 ; the invention may use any other suitable implementation of the actuator 20. [0017] The safety means 30 is configured such that it can drive the actuator 20 into a predefined safety position, in response to the detection of a predefined safety condition. The safety means 30 comprises a power storage 32 and a safety circuit 31. [0018] The power storage 32 is configured to store electrical energy which can be used to drive the actuator 20 into said predefined safety position. Preferably the electrical energy stored in the power storage should be large enough to be able to drive the actuator 20, with the indicated maximum (or nominal) power, force or torque, along a maximal drive path to said predefined safety position. The maximal drive path is the path, from the furthest position away from the safety position which the actuator 2 can be, to the safety position. The power storage 32 is preferably a capacitive power storage. Preferably, the power storage 32 comprises at least one supercapacitor. Preferably, the power storage 32 comprises multiple supercapacitors. However, in yet a further embodiment the power storage 32 comprises a battery or an accumulator; such a battery or accumulator can be a capacitive power storage. It should be understood that the invention is not limited to using capacitive power storages 32; the power storage 32 may be implemented using any suitable means. [0019] The safety circuit 31 is configured to detect a predefined safety condition and to electrically connect the power storage 32 to the actuator 20, in response to detecting said predefined safety condition. When the safety circuit 31 electrically connects the power storage 32 to the actuator 20, electrical energy which is stored in the power storage 32 drives the actuator 20 to said predefined safety position. Preferably the predefined safety position is a state in which the actuator 20 blocks the flow of fluid out of the fluid volume control device 2. In one embodiment, the

predefined safety position of the actuator 20 can be configured in the actuator system 1 , e.g. in the safety means 30 or in the actuator 20. The predefined safety condition could be a power breakdown or a power loss in the power input 10. This condition could be detected using any suitable means such as, for example, by measuring the voltage coming from the power input 10. However, other predefined safety conditions such as, for example, when a safety command is received, are also possible.

[0020] In one embodiment, the safety circuit 31 is further configured to electrically connect the power storage 32 to the power input 10, in response a charging condition being fulfilled. When the safety circuit 31 electrically connects the power storage 32 with the power input 10, voltage supplied by power source which is electrically connected to the power input 10, can pass to the power storage 32 to charge the power storage 32 with electrical energy. In a simple case, the charging condition could be fulfilled always, when the safety condition is not fulfilled; in other words the charging condition may be that there is no predefined safety condition detected; thus during the period in which there is no predefined safety condition detected then the safety circuit 31 electrically connects the power storage 32 to the power input 10, and a power source, which is electrically connected to the power input 10, will charge the power storage 32 with electrical energy; when a predefined safety condition is detected then the safety circuit 31 disconnects the power storage 32 from the power input 10, and electrically connects the power storage 32 to the actuator 20, and the energy stored in the power storage 32 drives the actuator 20 to said predefined safety position. In another example, the charging condition is fulfilled, when the energy stored in the power storage 32 falls under a predefined threshold; thus when energy stored in the power storage 32 falls under the predefined threshold then the safety circuit 31 electrically connect the power storage 32 to the power input 10 and the power source, which is electrically connected to the power input 10, will charge the power storage 32 with electrical energy; once the electrical energy which is stored in the power storage 32 is equal to, or exceeds, said threshold, then the safety circuit 31 disconnects the power storage 32 from the power input 10. A detailed description of a preferred safety circuit 31 can be found in the European patent EP2020073B1 which is incorporated by reference.

[0021] If the safety circuit 31 does not detect any of the predefined safety conditions, then the actuator 20 is driven by commands received in the actuator system 1 and/or by commands from a microcontroller of the actuator system 1.

[0022] The storage management means 40 is configured to provide storage management information. The storage management means 40 comprises a state means 41 , a consumption means 42 and a processing means 43.

[0023] The state means 41 is configured to determine a value indicating a state of the power storage 32. Preferably, the value indicates the capacity of the power storage 32. Preferably, the value is the capacity of the power storage 32. The value indicating the state of the power storage 32 can be determined by receiving said value from the safety means 30. For example, the safety circuit 31 could comprise measurement means for measuring said value indicating the state of the power storage 32 or for measuring another value which can be used to calculate said value indicating the state of the power storage 32. For example, the amount of electrical energy which is stored in the power storage 32 could be measured. It is also possible to measure the voltage output from the power storage 32 (and, for example, to use this measured voltage output to determine the amount of electrical energy which is stored in the power storage 32). It is further possible to measure the internal resistance of the power storage 32 (and, for example, to use this measured internal resistance to determine the amount of electrical energy which is stored in the power storage 32). Also, or alternatively, a value indicating the state of the power storage 32 could be measured manually by a user and inserted in a user input interface. The value indicating the state of the power storage 32 could be measured (e.g. in the safety means 30) or determined (e.g. in the storage management means 40) periodically at predefined intervals, or continuously, or in response to a certain predefined condition being fulfilled, e.g. when the electrical energy stored in the power storage 32 must be discharged. Said value may be stored (e.g. in the safety means 30 or in the storage

management means 40, respectively) for use, when requested or needed. It is possible to store only the last value determined or to store several values indicating the state determined at different points in time. In the latter case, an average value could be determined from those several stored values or a prediction for the remaining capacity in the future could be estimated from those several stored values. The prediction could be realised by fitting a function (e.g. a polynomic function) through those values for obtaining the value in the future on the basis of the fitted function. In another embodiment, the value indicating the state of the power storage 32 could be measured (e.g. in the safety means 30) or determined (e.g. in the storage management means 40) (only) in response to a request issued by the state means 41 or the processing means 43. [0024] The consumption means 42 is configured to determine a value indicating energy consumption for a predetermined safety actuation of the actuator 20. The predetermined safety actuation is defined as a

predetermined movement of the actuator 20 to the predetermined safety position. The predetermined safety actuation of the actuator 20 could be a movement of the actuator 20 from a first position, which is a position which is the furthest from the actuator's 20 predefined safety position, to the predefined safety position. The predetermined safety actuation 20 might depend on the configuration of the safety position. The safety actuation could also be a rotation of the mechanical actuator output through 90°. The value indicating the energy consumption could be the energy necessary to execute the predetermined safety actuation. The value could also be the current or power needed during the activation of the actuator 20. In combination with the time necessary to perform said predetermined safety actuation, the energy consumption for the

predetermined safety actuation can be computed. The value could also be a force or torque needed for the activation of the actuator 20, when mounted to the fluid volume control device 2. In combination with the translation or rotation, respectively, necessary for the predetermined safety actuation, the energy consumption for the predetermined safety actuation can be computed. Preferably, the value indicating energy consumption is measured. The value indicating energy consumption can be measured directly or indirectly, i.e. calculated from another measured value. The value or the other value is measured preferably in the actuator system 1 , preferably in the actuator 20. Preferably, the consumption means 42 receives the value indicating the energy consumption (from the actuator system 1 , in particular from the actuator 20). Additionally, or alternatively, the value indicating the energy consumption could be measured manually by a user and inserted in a user input interface. The value indicating the energy consumption could be measured (e.g. in the actuator 20) or determined (e.g. in the storage management means 40) periodically at predefined intervals, or continuously (always), or in response to a certain predefined condition being fulfilled (e.g. when the actuator 20 is activated or when there are modifications of the medium properties, i.e. flow, pressure or composition). The value indicating the energy consumption may be stored (e.g. in the actuator 20 or in the storage management means 40, respectively) for use, when requested or needed. It is possible to store only the last value determined or to store several values indicating the energy consumption determined at different points in time. In the latter case, a prediction of the future power/energy consumption can be calculated. In another embodiment, the value indicating the energy consumption could be measured (e.g. in the actuator 20) or determined (e.g. in the storage management means 40) (only) in response to a request issued by the state means 41 or the processing means 43, respectively. [0025] The processing means 43 is configured for computing the storage management information on the basis of the value indicating the state of the power storage 32 and of the value indicating the energy consumption for the predetermined safety actuation. In one embodiment, the storage management information indicates the end of the lifetime of the power storage 32. The end of lifetime of the power storage 32 is the condition, when the value indicating the state of the power storage 32 fall under or exceeds a threshold value depending on the value indicating the energy consumption of the predetermined safety actuation. Preferably, the end of lifetime of the power storage 32 is the condition, when the capacity of the power storage 32 falls under a safety capacity depending on the value indicating the energy consumption of the predetermined safety actuation. The information indicating the end of the lifetime of the power storage 32 could be a point in time or a time period. In one embodiment, the storage information indicates when the next maintenance check is due. The information indicating when the next maintenance check is due could be a point in time or a time period. The storage management information could generate an alarm, which is sent out. The alarm could be generated if, for example, the electrical energy stored in the power storage 32 is (soon) at a predefined threshold or is below a predefined threshold; for example the alarm could be generated if the electrical energy stored in the power storage 32 is insufficient to drive the actuator 20 to perform a

predetermined safety actuation; or the safety reserve for the actuation is not high enough for the energy (consumption) needed by the actuator 20 for the predetermined safety actuation. This could be tested by the energy stored in the power storage 32 dividing through the energy consumption for the predetermined safety actuation. By comparing the calculated value with a minimum required safety factor, an alarm could be triggered. The storage management information could be computed periodically or when a certain condition is fulfilled, e.g. when a new value is available in the state means 41 or in the energy consumption means 42, and stored for later use, when requested or needed. In another embodiment, the value indicating the state could be computed (only) upon request of the state means 41 or the processing means 43. [0026] If the electrical energy which is stored in the power storage 32 and/or the required energy consumption for the predetermined safety actuation is measured at different times, a prediction of the end of lifetime of the power storage 32 can be calculated.

[0027] The computed storage management information is given out through the output means 50. The output means 50 may comprise a display of the actuator system 1 (such as a computer screen, or a LCD). The output means 50 may comprise a loudspeaker or a light/LED. Such an output means could indicate the storage management information or the alarm. The output means 50 could also be a combined input/output means like a touch screen. Alternatively, or in addition, the output means 50 could comprise a communication interface for sending the computed storage management information to a processor or an external device. This communication interface could be used to send an alarm e.g. to a maintenance centre to replace the power storage 32, the safety means 30 or the device with the safety means 30.

[0028] The functional blocks 10 to 50 of Fig. 1 and described above can be realized by hardware and/or by software. Different blocks can be realized in a common hardware piece. The software parts of different functional blocks could be realized in a common microcontroller. It is also possible to realize functional blocks 10 to 50 in different hardware pieces, e.g. different microcontrollers, or even in different devices, e.g. some or all of the features of the storage management means 40 could located in a remote device, so that some or all of the functions of the storage

management means 40 are carried out partly or fully, in the remote device; the remote device may be, for example, a smartphone, wirelessly connected with an actuator and/or safety device which includes the remaining parts of the storage management means 40 (and includes the actuator means 20 and/or safety means 30).

[0029] In one embodiment, the actuator system 1 comprises a first device (which is preferably a remote device (i.e. remote to the actuator 20)) and at least one second device. The first device preferably comprises at least the output means 50 or the above-mentioned a combined

input/output means. The first device preferably comprises a user interface allowing a user to perform maintenance checks and/or to request the storage management information from the processing means 43. The second device preferably comprises the actuator 20 and the safety means 30 and said second device is preferably installed in the vicinity of the fluid volume control device 2. Preferably, the first device can access the second device by a wireless connection. This wireless connection could comprise at least partly a connection by a near field communication NFC, in particular on the basis of an RFID-chip. In one embodiment the actuator 20 and the safety means 30 could be provided in a single device. In another

embodiment, the actuator 20 and the safety means 30 are provided in two separate devices (i.e. the actuator 20 is provided in a first device and the safety means 30 is provided in a second device). In this case, it is possible that the safety means 30 in the second device could provide the described safety function for more than one actuators 20 provided in respective more than one first devices. The storage management means 40 and the safety means 30 could be provided in the same, single, second device, such that the first device can requests the storage management information from the processing means 43 in that single second device. Alternatively, the storage management means 40 could be in the first device such that the first device connects with the at least one of the one or more second devices for determining the values in the state means 41 and the consumption means 42. In a further embodiment, it is also possible that parts of the storage management means 40 are in the at least one second device and the remaining parts are in the first device. Finally, it is also possible that the actuator system 1 is realized in one single device as shown in Fig. 1.