Patent Application
20090128065
This Non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 096143389, filed in Taiwan, Republic of China on Nov. 16, 2007, the entire contents of which are hereby incorporated by reference.
1. Field of Invention
The present invention relates to a fan and in particular to a bathroom ventilator fan with a soft-start function.
2. Related Art
The bathroom is usually equipped with the bathroom ventilator fan. When the user turns on the switch, the bathroom ventilator fan starts to generate airflows in the bathroom and thus carry the bad smell or moisture out.
However, the conventional bathroom ventilator fan does not have the soft-start function. Thus, once the bathroom ventilator fan is switched on, it will rotate at full speed within a very short time. In this case, the user can obviously hear the noise caused by the bathroom ventilator fan. If the noise raising rate of the bathroom ventilator fan reaches about 10 dB per second, the noise will make the user feel uncomfortable.
In addition, to switch on the bathroom ventilator fan from still state to full speed state requires a very large start-up current. Thus, the inrush current, voltage spike or spike noise may occur in the starting moment when switching on the bathroom ventilator fan. Moreover, the arc (electric arc phenomenon) may be generated to damage the bathroom ventilator fan.
Furthermore, the electric power for driving the conventional bathroom ventilator fan is usually provided by the city electric power system. However, the city electric power system provides the AC power supply, so that the fan powered by the AC power supply usually consumes relatively more energy, which leads to larger power consumption.
In view of the foregoing, the present invention is to provide a fan with the soft-start function that can reduce the noise and prevent the inrush current, voltage spike or spike noise, thereby increasing the product reliability, extending the life time of the product and reducing the power consumption.
To achieve the above, the present invention discloses a fan with the soft-start function. The bathroom ventilator fan includes an impeller and a motor. The motor is coupled to the impeller and drives the impeller to rotate. The motor includes a control module for driving and controlling a rotation speed of the motor according to a soft-start signal. The soft-start signal includes a soft-start section and a target-driving section. The control module slowly increases the rotation speed of the motor from the soft-start section to reach the target-driving section.
As mentioned above, the fan of the present invention drives and controls the rotation speed of the motor according to the soft-start signal, so that the rotation speed of the bathroom ventilator fan can be increased slowly to the target rotation speed. Compared with the prior art, the present invention can reduce the noise and prevent the inrush current, voltage spike or spike noise, thereby increasing the product reliability and extending the life time of the product.
The present invention will become more fully understood from the subsequent detailed description and accompanying drawings, which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements.
With reference to
Referring to
After the fan is switched on, the control module 122 generates a soft-start signal SS for driving and controlling the rotation speed of the motor. Alternatively, the soft-start signal SS can be generated by an external device such as a soft-start circuit, and then the soft-start signal Ss is transmitted to the control module 122.
To make the present invention more comprehensive, the implemental circuits of the AC/DC converter 21 and the control module 122 will be described herein below. With reference to
The voltage-drop module 211 includes a transformer 2111, an optical coupler 2112, a controller 2113, a switch 2114 and a DC filter 2115. The transformer 2111 is coupled to the rectification module 212 and decreases the DC power source SDC to the work voltage S′W of the main body 121 of the motor. The optical coupler 2112, which is coupled to the transformer 2111 and the controller 2113, retrieves a feedback signal SF1 from the transformer 2111 and outputs a coupling signal SL to the controller 2113. The controller 2113, which is coupled to the optical coupler 2112 and the switch 2114, outputs a control signal SC to the switch 2114 according to the coupling signal SL. The ON/OFF of the switch 2114 can control the transformer 2111 to output stable work voltage S′W. The DC filter 2115 is coupled to the transformer 2111, the main body 121 of the motor and the control module 122 for receiving the work voltage S′W. Then, the DC filter 2115 filters the high-band frequency portion of the work voltage S′W and outputs the work voltage SW, which is the electrical energy for switching on the main body 121 of the motor and the control module 122.
The control module 122 includes a voltage-drop converter 1221, a Hall sensor 1222 and a micro control unit (MCU) 1223. The voltage-drop converter 1221 is coupled to the DC filter 2115, and is for decreasing the work voltage SW. Then, the decreased work voltage SW can be the power source for the Hall sensor 1222 and the MCU 1223. The MCU 1223 is coupled to the main body 121 and generates a soft-start signal SS for driving and controlling the rotation speed of the motor. When the motor is started, the magnetic field will change depending on the rotation speed. The Hall sensor 1222 is coupled to the MCU 1223 and senses the variation of the magnetic field so as to output a feedback signal SF2 to the MCU 1223. Then, the MCU 1223 controls the motor body 121 according to the feedback signal SF2. In addition, the implemental circuit of
The soft-start section A can be connected to the target-driving section B smoothly. Thus, the rotation speed of the motor 12 can be increased slowly, so that the inrush current, voltage spike or spike noise caused by the rapidly increased rotation speed can be prevented. The soft-start section A can be a linear curve or a second-degree curve. Therefore, when the bathroom ventilator fan 1 is switched on, the rotation speed of the motor 12 can be increased slowly from zero to the target rotation speed (such as a full speed). In the present invention, the noise raising rate of the bathroom ventilator fan 1 during the soft-start section A is not larger than 2 dB per second.
Alternatively, the bathroom ventilator fan with the soft-start function according to the present invention can be a DC fan. An AC/DC converter 21 is configured to convert the AC power source (city electric power) into the DC power source. Then, the DC power source is transmitted to the DC fan for driving the DC fan to rotate. Compared with the AC fan, the DC fan has the advantage of lower power consumption.
Moreover, the bathroom ventilator fan with the soft-start function according to the present invention can be an electrically commutated fan (EC fan), which has an AC/DC converter for converting the AC power source (city electric power) into the DC power source. Then, the DC power source drives the EC fan to rotate. In practice, the additional AC/DC converter is not needed for the EC fan, so the circuit design can be simplified.
In summary, the bathroom ventilator fan of the present invention drives and controls the rotation speed of the motor according to the soft-start signal, so that the rotation speed of the bathroom ventilator fan can be increased slowly to the target rotation speed. Compared with the prior art, the present invention can reduce the noise and prevent the inrush current, voltage spike or spike noise, thereby increasing the product reliability and extending the life time of the fan.
Although the present invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that fall within the true scope of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 096143389 | Nov 2007 | TW | national |
