Methods for controlling a voltage present at an electric fan

Patent metadata

Field	Value
Publication number	US-10833615-B2
Application number	US-201816195060-A
Country	US
Kind code	B2
Filing date	Nov 19, 2018
Priority date	Nov 27, 2017
Publication date	Nov 10, 2020
Grant date	Nov 10, 2020

Abstract

Methods for controlling a voltage present at an electric fan during a startup of the fan are disclosed herein. The fan serves to generate a flow of air for cooling a device. The method includes applying an output voltage of a power supply, which serves to supply voltage to the device, to the fan; and switching on and switching off the output voltage of the power supply applied to the fan by a switch pulse-width-modulated-controlled by a control unit so that the Root Mean Square value of the current flowing through the fan is less than a startup current of the fan.

First claim

The invention claimed is:

1. A method for controlling a voltage present at an electric fan during a startup of the fan, wherein the fan is configured to generate a flow of air for cooling a device, the method comprising:
applying an output voltage of a power supply to the fan, wherein the output voltage serves as the power supply of the device;
acquiring a fan voltage present at the fan;
calculating switch-on and switch-off times of the output voltage of the power supply applied to the fan as a function of the acquired fan voltage; and
switching on and switching off the output voltage of the power supply applied to the fan by a switch pulse-width-modulated-controlled by a control unit at the calculated switch-on and switch-off times such that a Root Mean Square value of a current flowing through the fan is less than or equal to a rated current of the fan.

2. The method of claim 1 , wherein a maximum value of the current flowing through the fan is less than or equal to twice a rated current of the fan.

3. The method of claim 1 , further comprising:
connecting a capacitor in parallel to the fan for stabilizing the fan voltage.

4. The method of claim 3 , further comprising:
connecting a choke limiting an increase in current such that the current flowing through the fan also flows through the choke and a closed switch.

5. The method of claim 4 , further comprising:
connecting a current measurement shunt such that the current flowing through the fan also flows through the current measurement shunt.

6. The method of claim 1 , further comprising:
connecting a choke limiting an increase in current such that the current flowing through the fan also flows through the choke and a closed switch.

7. The method of claim 1 , further comprising:
connecting a current measurement shunt such that the current flowing through the fan also flows through the current measurement shunt.

8. A circuit arrangement for supplying power to an electric fan, which serves to generate a flow of air for cooling a device, the circuit arrangement comprising: electrical contacts configured to connect the fan to a power supply of the device; a switch connected in series with the fan, wherein the switch is configured to switch on and switch off a current flowing through the fan, wherein the switch is configured to be opened and closed alternately by a pulse-width-modulated setting signal; and a control unit configured to acquire a fan voltage present at the fan, calculate switch-on and switch-off times of an output voltage of the power supply applied to the fan as a function of the acquired fan voltage, and provide the pulse-width-modulated setting signal at the switch based on the calculated switch-on and switch-off times such that a Root Mean Square value of the current flowing through the fan is less than a startup current of the fan.

9. A circuit arrangement of claim 8 , further comprising:
a capacitor connected in parallel to the fan.

10. The circuit arrangement of claim 9 , further comprising:
a choke connected in series with the fan, wherein the choke is configured to limit an increase in current.

11. The circuit arrangement of claim 10 , further comprising:
a flyback diode, wherein the flyback diode is switched so that, when the switch is opened, the choke is configured to continue to drive: the fan, the current via the flyback diode, the capacitor connected in parallel to the fan, or a combination thereof.

12. The circuit arrangement of claim 11 , further comprising:
a current measurement shunt connected in series with the fan.

13. The circuit arrangement of claim 8 , further comprising:
a choke connected in series with the fan, wherein the choke is configured to limit an increase in current.

14. The circuit arrangement of claim 13 , further comprising:
a flyback diode, wherein the flyback diode is switched so that, when the switch is opened, the choke is configured to continue to drive: the fan, the current via the flyback diode, a capacitor connected in parallel to the fan, or a combination thereof.

15. The circuit arrangement of claim 8 , further comprising:
a current measurement shunt connected in series with the fan.

16. A device comprising: an electric fan configured to generate a flow of air to cool the device; a power supply; and a circuit arrangement configured to supply power to the electric fan via the power supply, wherein the circuit arrangement comprises: electrical contacts that connect the electric fan to the power supply; a switch connected in series with the electric fan, wherein the switch is configured to switch on and switch off a current flowing through the fan, wherein the switch is configured to be opened and closed alternately by a pulse-width-modulated setting signal; and a control unit configured to acquire a fan voltage present at the fan, calculate switch-on and switch-off times of an output voltage of the power supply applied to the fan as a function of the acquired fan voltage, and provide the pulse-width-modulated setting signal at the switch based on the calculated switch-on and switch-off times such that a Root Mean Square value of the current flowing through the electric fan is less than a startup current of the electric fan.

17. The device of claim 16 , wherein an output voltage of the power supply is a direct current (DC) voltage.

18. The device of claim 16 , wherein the device is a switching device.

Assignees

• Hertz Dirk
• Ringer Florian
• Schoenenberg Marco
• Siemens Ag

Inventors

• Hertz Dirk
• Ringer Florian
• Schönenberg Marco

Classifications

• H02M3/155 Primary

  using semiconductor devices only · CPC title

• H02P7/282

  controlling field supply only · CPC title

• F04D25/08

  the working fluid being air, e.g. for ventilation · CPC title

• H02P1/18

  for starting an individual DC motor · CPC title

• H02P7/29 Primary

  using pulse modulation · CPC title