Methods for controlling a voltage present at an electric fan
AssigneeSiemens Aktiengesellschaft
InventorsDirk Hertz, Florian Ringer, Marco Schönenberg
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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.
Claims18
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.
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.
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.
Dependencies are inferred from the claim text.