EP-4739919-A1 - CONTROL DEVICE, FAN, FAN SYSTEM, AND METHOD FOR CONTROLLING FANS OF A FAN SYSTEM

Abstract

The invention relates to a control device (10) for controlling fans of a fan system, to a fan (7), to a fan system having a control device of this type, and to a corresponding method for controlling fans of a fan system. The invention also relates to a fan having a control circuit. The control device (10) is designed to determine, for each fan, a phase offset between an oscillation caused by interaction of the fans and a rotational reference point of the particular fan on the basis of sensor signals from the fans (7), and to temporarily adjust a rotational speed of a fan (7) on the basis of the phase offsets of the fans of the fan system in order to shift the phase offset of the fan.

Inventors

• Schübel, Dominik
• KRAUTH, Jacob

Assignees

• ZIEHL-ABEGG SE

Dates

Publication Date

20260513

Application Date

20250728

Claims (16)

1. 1. Control unit for controlling fans of a fan system, designed to determine, based on sensor signals from the fans, a respective phase shift between an oscillation caused by an interaction of the fans and a rotation reference point of the respective fan, and to temporarily adjust a rotation speed of a fan based on the phase shifts of the fans of the fan system in order to shift the phase shift of the fan.
2. 2. Control device according to claim 1, characterized in that the control device is designed to shift the phase shift of the fan by temporarily adjusting the rotational speed relative to the phase shift of a second fan such that the phase shift of the fan to the phase shift of the second fan has a predetermined ratio.
3. 3. Control unit according to claim 2, characterized in that the predetermined ratio corresponds to a phase difference of 180° with respect to the vibration caused by the interaction of the fans.
4. 4. Control unit according to one of claims 1 to 3, characterized in that the control unit is configured to specify the rotational speed of the fan in order to adjust the rotational speed of the fan temporarily, or characterized in that the control unit is configured to specify a desired phase shift for the fan in order to trigger a temporary adjustment of the rotational speed by the fan.
5. 5. Control unit according to one of claims 1 to 4, characterized in that the control unit is designed to calculate a desired phase shift of the fan using a digital twin or model of the fan system and to shift the phase shift of the fan according to the desired phase shift.
6. 6. Control unit according to claim 5, characterized in that the control unit is configured to determine, by means of the digital twin or model of the fan system, a desired state of the fan system which, viewed as a whole, exhibits lower vibrations than at least one other state of the fan system, and to determine the desired phase shift of the fan based on the desired state of the fan system.
7. 7. Control unit according to one of claims 1 to 6, characterized in that the control unit is designed to shift the phase shift of the fan by means of an iterative method.
8. 8. Control unit according to claim 7, characterized in that the control unit is configured to maintain, reverse the direction in which the phase shift is shifted, or complete the iterative process based on a sensor signal from an acceleration sensor with respect to the iterative process.
9. 9. Control unit according to one of claims 1 to 8, characterized in that the control unit is designed to shift the phase shift of a group of fans together.
10. 10. Control unit according to one of claims 1 to 9, characterized in that the control unit is configured to determine the rotation reference point of a respective fan based on a sensor signal of a position sensor of the fan, based on a sensor signal of an external position sensor or based on a sensor signal based on back-induced voltages of an electric motor of the fan.
11. 11. Control unit according to one of claims 1 to 10, characterized in that the control unit is designed to determine a temporal profile of the oscillation caused by the interaction of the fans based on a sensor signal from an accelerometer, and to determine the respective phase shift based on the temporal profile of the oscillation caused by the interaction of the fans.
12. 12. Fan comprising the control unit according to any one of claims 1 to 11.
13. 13. Fan system comprising a plurality of fans and the control unit according to any one of claims 1 to 11.
14. 14. Method for controlling fans of a fan system, comprising determining, based on sensor signals of the fans, a respective phase shift between an oscillation caused by an interaction of the fans and a rotation reference point of the respective fan, and temporarily adjusting a rotation speed of a fan based on the phase shifts of the fans of the fan system in order to shift the phase shift of the fan.
15. 15. Fan comprising a motor and a control circuit, wherein the control circuit is configured to obtain a control signal about a desired phase shift between a rotation reference point of the motor and an oscillation, in particular an oscillation caused by an interaction of several fans, and to adjust a rotation speed of the motor in the meantime to achieve the desired phase shift.
16. 16. Fan according to claim 15, characterized in that the control circuit is configured to determine the rotation reference point and to transmit information about the rotation reference point to a control unit for controlling fans of a fan system, and/or characterized in that the control circuit is configured to determine the phase shift between the rotation reference point of the motor and the vibration caused by the interaction of several fans and to transmit information about the phase shift to the control unit. ```

Description

CONTROL UNIT, FAN, FAN SYSTEM AND METHOD FOR CONTROLLING FANS OF A FAN SYSTEM The invention relates to a control unit for controlling fans of a fan system. The invention further relates to a fan with such a control unit, as well as a fan system with such a control unit. The invention further relates to a corresponding method for controlling fans of a fan system. The invention further relates to a fan with a control circuit. Fan systems with multiple fans of the type in question have been known in practice for years. In fan systems with multiple mechanically coupled fans, the fans influence each other's vibrations. The main cause of undesirable vibrations is excitation due to imbalance in individual fans. Since the fans in a multi-fan system are typically operated synchronously, their rotational speeds differ only minimally due to the shared analog or digital control. This difference in rotational speed is primarily attributable to manufacturing tolerances. With analog control, the difference is greater than with digital control, but these differences have a negligible impact on airflow. However, this slight difference in rotational speed can lead to observed vibrations within the system, which gradually build up and then decay. This is explained by the fact that the rotating excitation vectors of each individual device in the system change their relative positions due to the slight difference in rotational speed. With the vibration phases aligned, this results in mutual amplification ("oscillation"), while with opposing phases, it results in a different, less pronounced effect. Alignment of the oscillation phases during damping ("cancellation") of the oscillation amplitudes. Whether the oscillation phases have the same or opposite orientation depends on the mode shape and order of the oscillation. In a first-order oscillation, an opposite orientation occurs with an offset of 180°; for other orders, this may occur with a different offset. These effects can develop or change over several seconds to minutes, depending on the magnitude of the rotational speed difference. If the rotational frequency of all fans in the system is kept constant, the phase shift to each other also remains constant, thus also the vibrational influence and therefore the vibrational state of the individual devices and the multi-fan system. In extreme cases, excessively high vibration amplitudes or regular periods of excessive vibration amplitudes can lead to damage to the fans and/or peripheral components. EP 3282202 B1, for example, discloses a method for determining these resonance effects by measuring the pulsation of the current consumption at a given rotational speed, thus enabling maintenance or replacement of the respective fan mounting. However, this approach is reactive, meaning that only damage that has already been detected can be repaired retrospectively. For example, US7282873B2 discloses the use of mutually canceling interference of pressure waves to reduce noise emission and vibration of a system with at least two computer fans. The present invention is therefore based on the objective of designing and further developing a fan system of the type mentioned at the outset in such a way that resonance effects are avoided or the effects of resonance effects are mitigated. According to the invention, the foregoing problem is solved by the features of claim 1. Accordingly, the control unit in question for controlling fans of a fan system with multiple fans is designed to determine, based on sensor signals from the fans, a respective The control unit is also designed to temporarily adjust the rotational speed of a fan based on the phase shifts of the fans in the fan system, in order to shift the fan's phase shift. In accordance with the invention, it has first been recognized that the phase shift of a fan relative to a reference point can be shifted by briefly changing the fan's rotational speed relative to the phase shift of other fans. In particular, this brief or intermittent adjustment of the rotational speed allows the fan's phase shift to be adjusted so that the relative phase shift between two fans has a damping rather than an amplifying effect on the jointly generated vibration. Determining the phase shifts relative to a reference point—namely, the vibration caused by the interaction of the fans—and thus the relative phase shift between two fans, makes it possible to selectively adjust the phase shift of one of the fans to achieve the desired effect, i.e., the damping or cancellation of the vibration. This improves the acoustics and smooth operation of the fan system and prevents long-term damage to the system caused by the vibration. In particular, the control unit can be designed to shift the phase shift of the fan by temporarily adjusting its rotational speed relative to the phase shift of a second fan, such that the phase shift of the first fan has a predetermined ratio to that of the second fan. This predetermined