SYSTEM

TECHNICAL FIELD

The present invention generally relates to entrance systems. More specifically, the present invention relates to automatic door operators for use in entrance systems.

The present invention also relates to an associated method and computer program product.

Background

Automatic door operators are frequently used for controlling an electrical motor to open and close door members of entrance systems. Such opening and closing procedures are performed so that entrance and exit to buildings, rooms and other areas are facilitated. Automatic door operators are typically arranged in entrance systems located in both private and public areas, which are operating during long periods of time and under various conditions in terms of time of day, time of week, time of year, passage frequencies, etc. The automatic door operators therefore need to remain long term operational without malfunctions even during heavy traffic by persons, vehicles or objects passing through the entrance system.

Control of the electrical motor is typically performed by operating a controller to generate control signals. A microprocessor internal to the automatic door operator may be configured to generate these control signals by switching DC voltage on and off. An analog voltage defined by the duty cycle of the signals is thereby generated. As signal generation is based on switching transistors in a power electronics circuit on and off, there is a square signal generated which contains all frequencies over different frequency bands. Thus, electromagnetic interference (EMI) generated during the signal generation, caused by transistor switches, is very hard to remove or filter out. Furthermore, electromagnetic interference may also be generated from e.g. direct physical contact with a conductor, or by induction from nearby external sources, such as electric power cords, high-speed cabling, electric motors, Bluetooth devices, cellphones, and so forth. During operation, automatic door operators are therefore prone to be affected by electromagnetic interference from different sources. Because of this, the performance of circuits internal to the automatic door operator are degrading over time, which may cause circuit malfunctions. This is both costly and may lead to hazardous environments around the entrance system.

In the art of entrance systems, and automatic door operators in particular, there are currently no well-established solutions for minimizing incoming electromagnetic interference. Particularly, no solution has been suggested for minimizing the electromagnetic interference as generated due to transistor switches. Some arrangements use electrical filters, such as inductors and capacitors, to transform the EMI signals to heat instead of letting them out. However, this may lead to other problems such as overheating of electrical equipment.

Accordingly, it is an object of the present invention to reduce electromagnetic interference in automatic door operators.

SUMMARY

An object of the present disclosure is to provide an automatic door operator, an entrance system, a method and a computer program product which seek to mitigate, alleviate, or eliminate one or more of the above-identified deficiencies in the art and disadvantages singly or in any combination.

In a first aspect, an automatic door operator for use in an entrance system is provided. The automatic door operator comprises an electric motor; a power electronics arrangement; a controller being operatively connected to the power electronics arrangement; and a power supply for supplying power to the power electronics arrangement (and preferably also the controller), wherein the controller is configured to provide a plurality of pulsed control signals having a sweeping frequency to the power electronics arrangement for causing controlled actuation of the electric motor with power provided by the power supply.

The inventor of the disclosed invention has realized that the average electromagnetic interference can be lowered by providing pulsed control signals having a sweeping frequency. Such pulsed control signals having a sweeping frequency may effectively spread out the generated disturbances inherent to square signal generation within the power electronics arrangement over a certain time period. Consequently, certain components, such as e.g. inductors or capacitors, need not be arranged within the automatic door operator for filtering out excessive disturbance signals. The complexity of the automatic door operator is thus greatly reduced, and costs of filter components may consequently be vastly limited or even omitted. In particular, the complexity reduction is related to the simplicity of providing a software implemented control within the controller of the automatic door operator, as opposed to arranging an arbitrary number of filter components to manage disturbances. In one embodiment, each pulsed control signal comprises a plurality of pulses appearing at said sweeping frequency in a frequency band ranging between a first frequency and a second frequency.

In one embodiment, the first frequency is approximately 7.7 kHz and the second frequency is approximately 8.0 kHz. In one embodiment, the controller is configured to sweep the frequency of the appearing pulses of each pulsed control signal between values in the frequency band (preferably between the first frequency and the second frequency) two or more times per second.

In one embodiment, the controller is configured to sweep the frequency of the appearing pulses of each pulsed control signal between values in the frequency band (preferably between the first frequency and the second frequency) 10 times per second.

In one embodiment, the electric motor is an AC motor.

In one embodiment, the electric motor is a DC motor.

In a second aspect, an entrance system comprising an automatic door operator as defined in the first aspect and/or any of the embodiments associated therewith is provided. The entrance system further comprises one or more movable door members, wherein the automatic door operator is configured to cause movement of the one or more movable door members.

In a third aspect, a method of operating an automatic door operator comprising an electric motor, a power electronics arrangement, a power supply and a controller is provided. The method involves operating the controller to provide a plurality of pulsed control signals having a sweeping frequency to the power electronics arrangement for causing controlled actuation of the electric motor with power provided by the power supply.

In one embodiment, each pulsed control signal comprises a plurality of pulses appearing at said sweeping frequency in a frequency band ranging between a first frequency and a second frequency.

In one embodiment, the first frequency is approximately 7.7 kHz and the second frequency is approximately 8.0 kHz.

In one embodiment, providing a plurality of pulsed control signals further involves operating the controller to sweep the frequency of the appearing pulses of each pulsed control signal between values in the frequency band (preferably between the first frequency and the second frequency) two or more times per second.

In one embodiment, providing a plurality of pulsed control signals further involves operating the controller to sweep the frequency of the appearing pulses of each pulsed control signal between values in the frequency band (preferably between the first frequency and the second frequency) 10 times per second.

A fourth aspect is a computer program product comprising computer code for performing the method according to the third aspect and/or any of the embodiments associated therewith when the computer program code is executed by a processing device. The processing device may, for instance, be a controller as referred to above for any of the first to third aspects.

It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps, or components, but does not preclude the presence or addition of one or more other features, integers, steps, components, or groups thereof. All terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the [element, device, component, means, step, etc.]" are to be interpreted openly as referring to at least one instance of the element, device, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated. BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing will be apparent from the following more particular description of the example embodiments, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the example embodiments.

Figure l is a schematic block diagram of an automatic door operator according to one embodiment. Figures 2a-c illustrate control signal generation according to one embodiment.

Figure 3 is a schematic block diagram of an automatic door operator according to one embodiment.

Figure 4 is a schematic block diagram of an automatic door operator according to one embodiment. Figure 5 is a method of operating an automatic door operator according to one embodiment.

Figure 6 is a schematic illustration of an entrance system that comprises an automatic door operator and one or more movable door members. DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the invention will now be described with reference to the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

The terminology used in the detailed description of the particular embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like numbers refer to like elements.

With reference to Figure 1, one embodiment is shown of an automatic door operator 10. In this particular example, the automatic door operator 10 comprises a control arrangement 400 having a plurality of different components, a power supply 30, a power electronics arrangement 50, a revolution counter 21, an electric motor 20 and a transmission 22. The automatic door operator 10 is however not restricted to having these particular components, as other arrangements may be realized.

As shown in Figure 1, the electric motor 20 is connected to the transmission 22. An output shaft (not shown) of the transmission 22 rotates upon activation of the electric motor 20 and is connected to a linkage 24. The linkage 24 translates the motion of the output shaft into a movement of one or more door movable members (not shown) of an entrance system 100 (not shown). The entrance system 100 may for instance be a sliding door system, a swing door system, a revolving door system, or any combination thereof. One embodiment of the entrance system 100 will be described further below with reference to Figure 6.

The power supply 30 of the automatic door operator 10 supplies power to the electric motor 20, and preferably also to the controller 40 and other components of the automatic door operator 10. Alternative embodiments are however possible in which the controller 40 and other components of the automatic door operator 10 are powered by separate arrangements, such as another power supply, a battery, etc. The power supply 30 will be described more in detail with reference to Figures 3 and 4.

The controller 40 of the control arrangement 400 in Figure 1 is configured for performing different functions of the automatic door operator 10. In a preferred embodiment, the control arrangement 400 comprises a memory 41 associated with the controller 40. In alternative embodiments, the controller 40 may be arranged within the automatic door operator 10, but separate from the control arrangement 400.

The controller 40 may be implemented in any known controller technology, including but not limited to microcontroller, processor (e.g. PLC, CPU, DSP), FPGA, ASIC or any other suitable digital and/or analog circuitry capable of performing the intended functionality.

The memory 41 associated with the controller 40 may be implemented in any known memory technology, including but not limited to E(E)PROM, S(D)RAM or flash memory. In some embodiments, the memory 41 may be integrated with or internal to the controller 40. As seen at 41a, the memory 41 may store program instructions for execution by the controller 40, as well as temporary and permanent data used by the controller 40.

Functions related to the control arrangement 400 involve, for instance, providing a plurality of pulsed control signals 42 for controlled actuation of the electric motor 20. More specifically, the controller 40 of the control arrangement 400 is configured for providing the plurality of pulsed control signals 42. The pulses appear at a sweeping frequency in the pulsed control signals 42, as will be described in detail with reference to Figures 2a-c.

The term “sweeping” should be understood to include varying, differing, shifting, fluctuating, alternating, or similar, so that it is clear that the frequency can continuously comprise different values at different times.

Accordingly, the control arrangement 400, and more specifically the controller 40, is being operatively connected to the power electronics arrangement 50 for causing controlled actuation of the electric motor 20, with power provided by the power supply 30. The power electronics arrangement 50 will be described further in relation to

Figures 3 and 4.

The control arrangement 400 may further comprise one or more sensor units SI ... Sn configured to detect objects or persons in the vicinity of the entrance system 100. Hence, the controller 40 may receive inputs for managing movement of the movable door members based on the current traffic situation.

The automatic door operator 10 may furthermore comprise one or more additional sensor functions MPF; AS configured for detecting an emergency situation. The controller 40 is further responsive to the additional sensor functions MPF; AS to enter an evacuation mode. In the evacuation mode, the controller 40 is configured for controlling actuation of the electric motor 20 to generate torque for causing the movable door members in the entrance system 100 to move from closed position to open position and maintain in the open position even when there is a power failure in the power supply 30. Such power failure may e.g. involve an interruption in the power provided as e.g. AC mains (not shown). In this case, the electric motor 20 may be power supplied by a battery. In these or other embodiments, the additional sensor function AS may comprise means for receiving an external incoming alarm signal, such as a signal from a smoke detector, fire heat detector, remote alarm center, etc. To this end, the automatic door operator 10 may have a wired or wireless communication interface 44 for receiving the external incoming alarm signal AS. The interface 44 may, for instance, be compliant with GSM, UMTS, LTE, D-AMPS, CDMA2000, FOMA, TD-SCDMA, TCP/IP, Ethernet, Bluetooth, WiFi (e.g. IEEE 802.11, wireless LAN), Near Field Communication (NFC), RF-ID (Radio Frequency Identification), Infrared Data Association (IrDA), without limitation and in any combination. In the embodiment disclosed in Figure 1, the revolution counter 21, such as an encoder or other angular sensor, is provided at the electric motor 20 to monitor the revolution of a motor shaft of the electric motor 20. The revolution counter 21 is connected to an input of the controller 40. The controller 40 is configured to use one or more readings of the revolution counter 21, typically a number of pulses generated as the motor shaft rotates, for determining a current angular position, e.g. angles of the movable doors of the entrance system 100.

With reference to Figures 2a-c, an illustration of an individual control signal 42 is shown according to one embodiment. The control signal 42 is generated by the controller 40 of the control arrangement 400 of the automatic door operator 10. The instructions 41a for generating control signals 42 are preferably being stored within the memory 41 associated with the controller 40. Such instructions 41a may, for instance, involve decisions relating to the frequency of sweeping and generating the control signals 42. The instructions 41a may in preferred embodiments be fine-tuned depending on different markets and windings of the electric motor 20. For instance, instructions 41a may differ for different motor load requirements, regulatory or compliance needs, external influences such as e.g. traffic and/or weather, and so forth. Hence, the instructions 41a for providing the plurality of pulsed control signals 42 having a sweeping frequency may be updated, continuously or at a predetermined schedule, for different embodiments as realized by the person skilled in the arts of automatic door operators and controller technologies. As can be seen, the pulsed control signal 42 comprises a plurality of pulses 43.

In each one of the Figures 2a-c, the pulses 43 appear at a sweeping frequency in a frequency band ranging between a first frequency fi and a second frequency ϊi . The Figures 2a-c is an illustrative example of how a pulsed control signal 42 may be swept over the frequency band ϊi - fi at different operation periods of the automatic door operator 10.

The plurality of pulses 43 of the pulsed control signal 42 may, for instance, appear at said sweeping frequency in a frequency band ranging between a first frequency fi being 7.7 kHz and a second frequency ii being 8.0 kHz. Hence, in this specific example, the frequency of the plurality pulses 43 are appearing at fi = 7.7 kHz in Figure 2a, at an intermediate frequency fi = 7.85kHz in Figure 2b, and at ii = 8.0 kHz in Figure 2c. The skilled person will understand that as the frequency of the pulsed control signal 42 is swept between the first frequency fi and the second frequency ii, the intermediate frequency fi will increase from just above fi to just below ii and therefore sequentially take on a large number of frequency values, not just 7.85kHz. Rather, the intermediate frequency fi will have the value 7.85kHz only half ways through the sweeping period.

In the Figures 2a-c, the varied frequency fi, fi, ii is indicated by the number of pulses 43 appearing in a given time period of the pulsed control signal 42, or, equivalently, as the inverse of the period time Ti, Ti, T ₂ of the pulsed control signal 42.

In one embodiment, the first frequency fi is 7.7 kHz ± 0.1 kHz and the second frequency f2 is 8 kHz ± 0.1 kHz. Hence, the frequency of the pulses 43 appearing in the pulsed control signal 42 is swept between approximately 7.7 kHz and approximately 8.0 kHz. “Approximately” in this sense is referring to that the range of the frequency band may vary slightly during operation. For instance, an approximate range of the frequency band therein could also be e.g. 7.6 kHz to 8.1 kHz, or 7.8 kHz to 7.9 kHz. Alternatively, the first frequency fi is approximately 6.0 kHz and the second frequency f2 is approximately 10.0 kHz, or any subrange therein. Yet alternatively, the first frequency fi is any suitable lower threshold value and the second frequency f2 is any suitable upper threshold value, so that the electric motor 20 can be controlled appropriately. The controller 40 is configured to sweep the frequency of the appearing pulses 43 of each pulsed control signal 42 between values in the frequency band, i.e. typically between the first frequency fi and the second frequency Ϊ2. This may be done according to the instructions 41a stored in the memory 41 associated with the controller 40. The frequency may in one embodiment be swept two or more times per second.

In an alternative embodiment, the frequency is being swept 10 or more times per second. The controller 40 is however not restricted to a certain frequency sweeping rate, as it may differ depending on the configuration of the automatic door operator 10. In practical usage, the controller 40 may be configured to sweep the frequency according to an optimal rate, the optimal rate being anywhere between two and an arbitrary number of times per second.

With reference to Figures 3-4, two examples of automatic door operators 10 are shown. The embodiments comprise different power supplies 30, different power electronics arrangements 50, different controller 40 configurations, and different electric motors 20, However, in both of the embodiments shown, the controllers 40 are configured to provide a plurality of pulsed control signals 42 having a sweeping frequency to the power electronics arrangements 50. This is performed for causing controlled actuation of the electric motors 20 with power provided from the power supplies 30. In both of the embodiments shown according to Figures 3 and 4, each power electronics arrangement 50 comprises a frequency inverter. The frequency inverter is adapted to receive fixed DC voltage from a respective power supply 30, and a plurality of control signals 42 from a respective controller 40, and convert it to adjustable frequency and voltage output for control of the respective electric motor 20. The power electronics arrangements 50 operating in conjunction with the controllers 40 may be modulated using PWM (Pulse-width modulation). Hence, the average power as delivered by the pulsed control signals 42 can be reduced by dividing it up into discrete parts. The average of the voltage fed to the respective electric motor 20 is controlled by turning switches within the power electronics arrangements 50 on and off at a predetermined rate. The longer the switches are on compared to the off-periods, the higher the total power supplied to the respective electric motor 20. The controllers 40 may be configured to provide the pulsed control signals 42 that control the applied voltage on a gate driver, which provides the required PWM frequency with less harmonics at the output of the power electronics arrangement 50. As has been described above, the frequency of the plurality of the pulsed control signals 42 is effectively swept for reducing the overall electromagnetic interference.

In Figure 3, the automatic door operator 10 comprises an electric motor 20 being an alternating current (AC) motor. The power electronics arrangement 50 is configured to cause controlled actuation of the AC motor 20, based on power provided by the power supply 30 and the pulsed control signals 42 having a sweeping frequency as received from the controller 40. The power supply 30 comprises a rectifier for converting incoming alternating to direct current used to power the controller 40 and the power electronics arrangement 50. Further to this, the automatic door operator 10 comprises a filter component, such as a capacitor bus, for storing and smoothing DC power to be supplied to the other components of the automatic door operator 10. The power electronics arrangement 50 shown in Figure 3 comprises a plurality of IGBTs (Insulated Gate Bipolar Transistors), wherein each IGBT is a semiconductor having three terminals working as a switch for moving electrical current within the power electronics arrangement 50. Typically, the power electronics arrangement 50 of the embodiment shown in Figure 3 comprises six IGBTs, each IGTB pulsing voltage for an arbitrary number of times per second. However, fewer or more IGBTs may also be realized in other embodiments. For the power electronics arrangement 50 having six IGBTs, each IGBT is receiving a corresponding control signal 42 as generated from and transmitted by the controller 40. Hence, three-phase motor control of the AC motor 20 is caused, with power provided by the power supply 30. Alternatively, the power electronics arrangement 50 shown in Figure 3 may be based on any appropriate power electronics commonly used for controlling an AC motor 20 in an automatic door operator 10, such as MOSFET (or even BJT). The control signals 42 provided by the controller 40 may accordingly be reconfigured to be compatible with the arranged power electronics. The power electronics arrangement 50 may, as mentioned above, comprise the gate driver, i.e. a power amplifier that accepts a low-power input in the form of the pulsed control signals 42 from the controller 40 and produces a high-current drive input for the gate terminals of the high-power transistors, e.g. IGBTs or MOSFETs.

In Figure 4, the automatic door operator 10 comprises an electric motor 20 being a direct current (DC) motor 20. The power electronics arrangement 50 is configured to cause controlled actuation of the DC motor 20, based on power provided by the power supply 30 and the pulsed control signals 42 having a sweeping frequency as received from the controller 40. The input of the power supply 30 is directly coupled to a direct current power source, so that power can be supplied to the controller 40 and the power electronics arrangement 50. The power electronics arrangement 50 shown in Figure 3 comprises an H-bridge configuration having a set of switches for moving electrical current within the power electronics arrangement 50. Preferably, the H-bridge configuration comprises four switches. For the power electronics arrangement 50 having an H-bridge, the power electronics arrangement 50 is receiving two control signals 42 as generated from and transmitted by the controller 40. Hence, motor control of the DC motor 20 is caused, with power provided by the power supply 30.

Figure 5 shows an embodiment of a method 200 of operating an automatic door operator 10. The automatic door operator comprises an electric motor 20, a power electronics arrangement 50, a power supply 30 and a controller 40. The method 200 involves operating 210 the controller 40 to provide a plurality of pulsed control signals 42 having a sweeping frequency to the power electronics arrangement 50. The power electronics arrangement 50 accordingly causes controlled actuation of the electric motor 20 with power provided by the power supply 30. Such operation is typically performed by providing the controller 40 with programmable instructions in an associated memory (such as, for instance, the elements 41 and 41a as described for the preceding drawings). Hence, long-term operation of the automatic door operator 10 is effective without necessarily requiring operator maintenance.

In one embodiment, the controller 40 may be self-learning in order to intelligently sweep the frequency of the generated control signals 42. The intelligent sweeping of frequency may be based on bearing fault diagnostics and machine health attributes, as retrieved from any of the sensor units and/or revolution counter 21. For instance, when one or more of the sensors provide the controller 40 with sensor data, the controller 40 attempts to recognize patterns by itself. The controller 40 thus generates autonomous decisions, to adjust the operation of providing pulsed control signals 42 having a sweeping frequency. As an example, the controller 40 may learn that the electric motor 20 is operating at a reduced capacity, and thus sweep the frequency of the control signals 42 accordingly. Both supervised and unsupervised learning algorithms may be implemented and/or applied, such as for example regression algorithms, decision trees, K-means, K-nearest neighbours, neural networks, support vector machines or principal component analysis. An intelligent system as described may learn from continuously receiving accurate sensor readings from the different sensors.

Bearing fault diagnostics and/or machine health attributes generated autonomously may be stored in the memory 41 associated with the controller 40 for use in controlling actuation of the electric motor 20 of the automatic door operator 10.

The method 200 may alternatively involve a step of operating 212 the controller 40 to sweep the frequency of the appearing pulses 43 of each pulsed control signal 42 between values in the frequency band two or more times per second.

The method 200 may further involve a step of operating 214 the controller 40 to sweep the frequency of the appearing pulses 43 of each pulsed control signal 42 between values in the frequency band 10 times per second. The skilled person realizes that the steps of operating 212; 214 the controller to sweep the frequency can be performed an arbitrary number of times per second.

In embodiments of the invention according to any of the figures disclosed herein, a computer program product comprising computer code for performing the method 200 when the computer program code is executed by a processing device may be provided. The processing device may in preferred embodiments of the invention be the controller 40 as disclosed herein. Alternatively, the processing unit may be provided separately and be implemented using any similar controller technology as described in association with the controller 40.

Figure 6 is a schematic block diagram illustrating an entrance system 100 in which the inventive aspects of the present invention may be applied. The entrance system 100 may be designed for installation in a building to control access into the building from the outside of said building, or between different sections of the building. The entrance system 100 comprises one or more movable door member(s) 110a...110h, and an automatic door operator 10 coupled to cause movement of the door member(s)

110a... 110h from at least a closed position in which passage through said entrance system 100 is prevented, to an open position in which passage is admitted. In Figure 6, the linkage 24 - which was described with relation to Figure 1 - can be seen as coupled with the door member(s) 110a... 110h to take part in their opening and closing movement. As can be seen in Figure 6, the door member(s) 110a... 110b may be either one of a swing or sliding door member 120, a revolving door member 130 or a lifting door member 140.

The invention has been described above in detail with reference to embodiments thereof. However, as is readily understood by those skilled in the art, other embodiments are equally possible within the scope of the present invention, as defined by the appended claims. It is recalled that the invention may generally be applied in or to an entrance system 100 having one or more movable door member not limited to any specific type. The or each such door member may, for instance, be a swing door member, a revolving door member, a sliding door member, an overhead sectional door member, a horizontal folding door member or a pull-up (vertical lifting) door member.