US 12,442,383 B2
Fan drive system
Elias Nielsen, Nordborg (DK)
Assigned to DANFOSS POWER SOLUTIONS INC., Ames, IA (US)
Appl. No. 18/250,264
Filed by Danfoss Power Solutions Inc., Ames, IA (US)
PCT Filed Dec. 20, 2021, PCT No. PCT/IB2021/022244
§ 371(c)(1), (2) Date Apr. 24, 2023,
PCT Pub. No. WO2022/144591, PCT Pub. Date Jul. 7, 2022.
Claims priority of application No. 102020216601.3 (DE), filed on Dec. 30, 2020.
Prior Publication US 2023/0417253 A1, Dec. 28, 2023
Int. Cl. F04D 27/00 (2006.01); F04D 25/04 (2006.01)
CPC F04D 27/004 (2013.01) [F04D 25/04 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A method for controlling the speed of a hydraulic fan system comprising a fan operated by a hydraulic motor which is driven by a hydraulic variable displacement pump comprising a displacement volume adjusting element whose tilt angle can be adjusted by means of controlling a tilt current supplied to an electronic displacement control unit, the method comprising the following repetitive steps:
a) Determining a volumetric flow rate of the hydraulic variable displacement pump by means of measuring operational parameters of the hydraulic variable displacement pump;
b) Calculating a fan speed based on the volumetric flow rate determined in step a) using equations representing the physical correlation between the volumetric flow rate and the fan speed;
c) Determining a fan speed error by comparing the calculated fan speed of step b) with a fan speed set value provided by an input device;
d) Determining a tilt current adaptation supplied to the electronic displacement control unit in order to adjust the tilt angle of the displacement volume adjusting element, such that the fan speed error is reduced, wherein the tilt current adaptation is calculated based on the fan speed error using a P-, PI-, PID-, Fuzzy- or a Predictive Controller or a similar type of linear or non-linear controller;
wherein the following steps are executed simultaneously to the steps c) to d):
e) Deriving an ideal tilt current value from the calculated fan speed of step b);
f) Performing safety actions in order to prevent damage to the fan, if the difference between the ideal tilt current value derived in step e) and the tilt current adaptation determined in step d) is higher than a tilt current threshold value, and wherein a warning signal is sent to an operator, to a control interface, or to a user interface of the fan system, or to a work machine hosting the fan system, if the tilt current threshold value or the speed error threshold value is exceeded.