Patent Application
20080304303
1. Field of the Invention
The invention relates to a power converting device, more particularly to a power converting device adapted for use in a recreational vehicle.
2. Description of the Related Art
However, in the conventional power converting device 1, even though the temperature of the heat sink is within a low temperature range, the fan 17 is controlled by the fan control circuit 18 to operate at a corresponding low rotational speed such that low fan noise effect in response to low rotational speed operation of the fan 17 occurs.
Therefore, the object of the present invention is to provide a power converting device that can ensure safe operation with relatively low fan noise effect.
According to the present invention, a power converting device comprises:
a power converting unit for converting an AC voltage input into a DC voltage output;
a cooling fan for dissipating heat generated by the power converting unit;
a detecting unit connected electrically to the power converting unit for detecting a current output of the power converting unit and for generating a control signal corresponding to the current output detected thereby; and
a controller connected electrically to the cooling fan and the detecting unit for controlling rotational speed of the cooling fan in accordance with the control signal from the detecting unit.
Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings, of which:
Before the present invention is described in greater detail, it should be noted that like elements are denoted by the same reference numerals throughout the disclosure.
Referring to
The power converting unit 200 converts an AC voltage input, such as AC 100V, into a DC voltage output, such as DC 13.6V, that is adapted to be supplied to an external load device (not shown). Since the feature of the present invention does not reside in the power converting unit 200, which is known to those skilled in the art, further details of the same are omitted therein for sake of brevity. An example of the power converting unit 200 suitable for application in this invention is described in US 2006/008031, the entire disclosure of which is incorporated herein by reference.
The cooling fan 20 dissipates heat generated by the power converting unit 200.
The detecting unit 28 is connected electrically to the power converting unit 200 for detecting a current output (or load current) of the power converting unit 200 and for generating a control signal corresponding to the current output detected thereby. In this embodiment, the control signal is a voltage signal having a linear proportion relation with the current output of the power converting unit 200.
The controller 27 is connected electrically to the cooling fan 20 and the detecting unit 28 for controlling rotational speed of the cooling fan 20 in accordance with the control signal from the detecting unit 28.
Referring to
The controller 27 controls the cooling fan 20 to shut down upon detection that the current output of the power converting unit 200 is smaller than 15% of a predetermined rated current value. In this case, the power converting device 2 is operated in a low load state without fan noise effect.
The controller 27 controls the cooling fan 20 to operate at a predetermined low rotational speed using known PWM control techniques upon detection that the current output of the power converting unit 200 is within a range of 15%˜55% of the predetermined rated current value. In this case, the power converting device 2 is operated in a medium load state with relatively low fan noise effect.
The controller 27 controls the cooling fan 20 to operate at a variable rotational speed changeable with the current output of the power converting unit 200 (i.e., the rotational speed is proportional to the current output of the power converting unit 200) using known PWM control techniques upon detection that the current output of the power converting unit 200 is within a range of 55%˜70% of the predetermined rated current value. In this case, in order to ensure heat dissipation of the power converting unit 200 as a result of a high load output, the rotational speed of the cooling fan 20 is varied with the current output of the power converting unit 200 such that the power converting device 2 can be safely operated with dynamically adjusted fan noise effect.
The controller 27 controls the cooling fan 20 to operate at a predetermined high rotational speed using known PWM control techniques upon detection that the current output of the power converting unit 200 is greater than 70% of a predetermined rated current value, thereby ensuring fast heat dissipation.
Referring to
The controller 27′ controls the cooling fan 20 to shut down upon detection that the current output of the power converting unit is smaller than 50% of the predetermined rated current value and that the temperature of the power converting unit 200 is lower than 40° C.
The controller 27′ controls the cooling fan 20 to operate at a variable rotational speed changeable with the temperature of the power converting unit 200 (i.e., the rotational speed of the cooling fan 20 is proportional to the temperature of the power converting unit 200) using known PWM control techniques upon detection that the current output of the power converting unit 200 is within a range of 50%˜80% of the predetermined rated current value and that the temperature of the power converting unit 200 is higher than 40° C.
The controller 27′ controls the cooling fan 200 to operate at the predetermined high rotational speed using known PWM control techniques upon detection that the current output of the power converting unit 200 is greater than 80% of the predetermined rated current value and that the temperature of the power converting unit 200 is higher than 60° C.
On the other hand, the controller 27′ can also control the rotational speed of the cooling fan 20 in accordance with the temperature signal from the temperature sensing unit 29 independent of the current output of the power converting unit 200.
Referring to
The controller 27′ controls the cooling fan 200 to shut down upon detection that the temperature of the power converting unit 200 is lower than 40° C.
The controller 27′ controls the cooling fan 200 to operate at a variable rotational speed changeable with the temperature of the power converting unit 200 (i.e., the rotational speed of the cooling fan 20 is proportional to the temperature of the power converting unit 200) using known PWM control techniques upon detection that the temperature of the power converting unit 200 is within a range of 40° C.˜60° C.
The controller 27′ controls the cooling fan 200 to operate at the predetermined high rotational speed using known PWM control techniques upon detection that the temperature of the power converting unit 200 is higher than 60° C.
In sum, due to the presence of the detecting unit 28 and the temperature sensing unit 29, the controller 27, 27′ can appropriately control the rotational speed of the cooling fan 20 in accordance with at least one of the current output and the temperature of the power converting unit 200. In particular, when the temperature of the power converting unit 200 is lower than 40° C. and when the current output of the power converting unit 200 is smaller than 15% of the predetermined rated current value, the cooling fan 20 is shut down so that no fan noise is generated during low load conditions.
While the present invention has been described in connection with what are considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.
