Abstract:
A universal low-power ceiling fan controller includes a brushless DC motor in a ceiling fan casing, a microprocessor connected to a power supply that operates with a remote-control device and has a transmitter and a receiver for transmitting data signals to the microprocessor by wireless transmissions, a driving device installed between the microcontroller and the motor for turning on or off a fan, and a feedback device having at least three Hall components for continuously sending feeding back a position change to the microcontroller for determining the motor speed, such that the microcontroller receives the signals of the remote-control device and the driving device drives the motor to rotate, and sample signals of the feedback device is fed back to the microcontroller to determine and conduct an automatic compensation, so as to maintain a constant speed of the vanes of the ceiling fan and lower the electric power consumption.

Description:
FIELD OF THE INVENTION 
   The present invention relates to a controller, and more particularly to a low-power ceiling fan controller that uses a microcontroller to control and drive a brushless motor and operates it with a feedback device to continuously and automatically determine a position feedback for an automatic compensation of the microcontroller, so as to achieve a constant rotary speed and a remote-control linear stepless speed adjustment of the ceiling fan. 
   BACKGROUND OF THE INVENTION 
   According to evaluations made by the Electric Power Research Institute (EPRI), the consumption of electric power is approximately 40% of the total energy capacity. Since the motor driving components used in electric equipments often require electric power as their energy source, therefore it is a key point for the design to reduce the power consumption of a motor. The motor structure adopts a continuous driving method and is divided into two types: a brush structure and a brushless structure, and the brush motor is a DC motor, and the brushless motor is a brushless DC sensing motor; wherein the brush structure includes an electric brush and a rectifier. Therefore, the using life of the motor will be very limited, the electromagnetic interference will be high, and the noise will occur, if the motor is under the friction and contact for a long time, and thus causing a poor contact easily and occupying larger volume, and its brush requires maintenance. The brushless motor such as a DC brushless motor adopts an electronic commutation structure having a speed up to 10,000 rpm and a wider speed range. In addition, the brushless DC motor features a low rotor inertia, a low electromagnetic interference, a free carbon brush maintenance, a free carbon brush dust, and a small volume. Therefore, its application is superior to the brush DC motor, and the present invention uses a brushless DC motor as the main drive. 
   As to the ceiling fan structure, a motor is used for driving the vanes to rotate and produce winds, so as to achieve the air cooling effect. However, the technology of the ceiling fans tends to have additional functions including a sleep mode, an air conditioning, an expedited air-conditioned circulation, a decoration, an illumination, a low power consumption, and a remote control function, in addition to providing wind and dissipating heat. 
   Since the use of the ceiling fans is very popular in everyday life and users have high demands on stability, safety, comfortability, convenience for its functions, therefore finding a way for lowering the power consumption, adjusting the speed stepless, achieving the remote control, and the low-speed noiseless functions becomes a key point for the design of a good ceiling fan system in the industry. 
   SUMMARY OF THE INVENTION 
   Referring to  FIGS. 6 and 7 , a prior art ceiling fan structure  80  includes a DC brushless motor  81  disposed inside a ceiling fan casing for driving the vanes  82  to produce airflows, wherein the brushless DC motor  81  comprises a stator  83  and a rotor  84 , and the rotor  84  includes a plurality of mutually repelled permanent magnets disposed in a circular yoke, characterized in that the stator  83  includes a multi-polar magnetism of more than two poles, and each magnet includes a coil wound around the magnet and Hall components  85 ,  86  on the sensing surface of a specific magnet. The Hall components  85 ,  86  are coupled to an electronic switch module  87 , and each switch module of the electronic switch module  87  is coupled to the power supply and each electromagnetic coil, and the Hall components  85 ,  86  are used for detecting the polarity change of the permanent magnet, such that the corresponding electromagnetic activation drives the rotor to rotate, and the coil is electrically connected, and the best angle for the electromagnetic polarity is changed when the coil is electrically connected, so as to improve the motor performance. 
   Referring to  FIG. 8  for another ceiling fan driving control device, a remote control coder  90  is used for a ceiling fan that comprises a microprocessor  91 , a high-frequency receiver  92 , and an external memory (EEPROM)  93 , wherein the microprocessor  91  is connected to a power supply  94  for supplying power, and I/O contact points of the microprocessor  91  are coupled to a lamp  95  and a fan motor  96  respectively. Further, other I/O contact points of the microprocessor  91  are connected to a high-frequency receiver  92  and an external memory  93 , wherein the external memory  93  has the function of reading and writing memory in a power failure and can be used for automatically detecting and setting up the decoded address of the corresponding transmitter by a RF coding function after the ceiling fan is powered on, so as to facilitate users to change the decoded address of the ceiling fan remote control coder  90  and improve the inconvenient prior art that requires removing the whole ceiling fan before operating the switch address code of a remote control device. Such ceiling fan driving control device provides a remote control coder that can avoid interferences and change the corresponding decoding address of remote control coder. However, such structure only provides a function of transmitting signals to drive the lamps  95  and ceiling fan motor  96 , so as to achieve the function of the stepless speed adjusting function. 
   Wind flow is one of the conditions of selecting a ceiling fan, and the quantity of wind flow determines the rotary speed of the motor. To maintain a constant wind flow, the rotary speed of the motor must be stable. However, if the vanes of the foregoing prior art structure are changed and the load is varied, or the voltage and frequency of the city electric power are unstable and the rotary speed is changed, the voltage will vary accordingly. In view of the shortcoming of the prior art structure that consumes much electric power for driving the motor, the inventor of the present invention invented a low-power ceiling fan controller. 
   To overcome the foregoing shortcomings, the present invention discloses a universal low-power ceiling fan controller installed inside a ceiling fan casing, which comprises a brushless DC motor installed in the ceiling fan casing, a microcontroller coupled to a power source and operating with a remote control device including a transmitter and a receiver for sending data signals to the microcontroller by a wireless transmission method, a driving device installed between the microcontroller and the brushless DC motor for turning on or off the ceiling fan, and a feedback device having at least three Hall components for continuously sensing a position variation and feeding back the position variation to the microcontroller to determine the speed of the brushless DC motor. With the foregoing components, the microcontroller receives a signal from the remote control device, and the driving device drives the brushless DC motor to rotate by means of a sample signal feedback of the feedback device for the microcontroller to determine and conduct an automatic compensation, so as to maintain a constant rotary speed of the vanes of the ceiling fan while reducing the power consumption. 
   The primary objective of the present invention is to provide a universal low-power ceiling fan controller for maintaining a constant rotary speed of the fan regardless of the quantity, weight, or different specification of the vanes of the ceiling fan. 
   The secondary objective of the present invention is to provide a universal low-power ceiling fan controller that has a universal voltage, and maintains a constant rotary speed, regardless of the voltage and frequency issues of city electricity in different countries and the instability of their variations. 
   A further objective of the present invention is to provide a universal low-power ceiling fan controller having a remote-control stepless rotary speed adjusting function. 
   Another further objective of the present invention is to provide a universal low-power ceiling fan controller applicable for ceiling fans with a brushless DC motor, so as to greatly reduce the power consumption and maximize the power saving effect. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     To make it easier for our examiner to understand the objective, shape, assembly, structure, characteristics and performance of the present invention, the following embodiments accompanied with the related drawings are described in details. 
       FIG. 1  is a flow chart of a preferred embodiment of the present invention; 
       FIG. 2  is a schematic view of a preferred embodiment of the present invention; 
       FIG. 3  is a schematic circuit diagram of a preferred embodiment of the present invention; 
       FIG. 4  is another schematic circuit diagram of a preferred embodiment of the present invention; 
       FIG. 5  is a flow chart of another preferred embodiment of the present invention; 
       FIG. 6  is a cross-sectional view of a prior art structure; 
       FIG. 7  is a schematic view of a control system of a prior art structure; and 
       FIG. 8  is a flow chart of another prior art structure. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to  FIGS. 1 to 2 , the present invention provides a universal low-power ceiling fan controller installed inside a ceiling fan casing, which comprises a brushless DC motor  21 , a microcontroller  22 , a remote control device  23 , a driving device  24 , and a feedback device  30 . 
   The brushless DC motor  21  is installed in the ceiling fan driving structure  80  for driving the vanes of the ceiling fan. 
   The microcontroller  22  is connected to a power supply  40  for providing the signal processing, analysis, control, detection, and transmission functions. 
   The remote control device  23  uses radio frequency (RF) and infrared (IR) wireless transmission methods to operate with a receiving antenna  231  and a receiver  232  to send the data signal to the microcontroller  22 , wherein the receiver  232  is connected to the microcontroller  22 , such that the signal is sent to the microcontroller  22  after the signal is received and converted. 
   The driving device  24  is a driving circuit with a three-arm switch structure comprising six power switches and including a metal oxide semiconductor field effect transistor  241  or a bipolar junction transistor (BJT) installed between the microcontroller  22  and the Brushless DC motor  21  for receiving an instruction given by the microcontroller  22  to control the operation of turning on or off the brushless DC motor  21 . 
   The feedback device  30  includes three Hall components  31  arranged at predetermined positions adjacent to each other and at 60 degrees or 120 degrees in the brushless DC motor  21  and having a magnetic sensing device for continuously detecting a position change and feeding back the detected signal to the microcontroller  22  for determining the speed of the brushless DC motor  21 . 
   Further, a power supply  41  is installed at the driving circuit between the power supply  40  and driving device  24  for controlling a constant speed of the brushless DC motor  21  to provide an easy-to-control and stable voltage amplitude (approximately 6V˜40V), and a circuit protection device  42  is installed between the power supply  41  and the driving device  24 , such that the driving circuit can reduce circuit damages caused by improper loading operations. 
   A power accessory device  50  is installed between the power supply  40  and the microcontroller  22  for outputting a lower-power and stable accessory power supply (approximately 5V) to the microcontroller  22  and having an electric potential detecting function for monitoring the system voltage change anytime to avoid system cracks caused by an unstable voltage of the microcontroller. 
   To make it easy for our examiner to understand the structure features, technical measures and expected performance, the present invention is described by a preferred embodiment accompanied with related drawings as follows: 
   The invention adopts a design of using the microcontroller  22  to control a constant rotary speed of the brushless DC motor  21 , so that when the brushless DC motor  21  rotates, the Hall components  31  disposed adjacent to the brushless DC motor  21  detects the position status between the two and feeds back the signal to the microcontroller  22 , and the microcontroller  22  uses such signal to compute the time difference between the two and convert the two into the rotary speed of the brushless DC motor  21 . After the data signal is analyzed and processed, a command signal is transmitted to the driving device  24  for compensating the speed of the brushless DC motor  21 . If the rotary speed is too slow, then an AC/DC high-frequency switching converter is used for increasing the AC voltage, and if the speed is too fast, then the AC voltage is lowered, so as to achieve the constant speed effect. In the meantime, the updated position information is obtained, and the sampling and feedback are conducted continuously between each microcontroller  22  and Hall component  31 , and thus the present invention can still maintain a predetermined speed and produce a fixed quantity of wind flow when it is necessary to change the vanes of a ceiling fan with a different material specification and weight loading or the problems caused by insufficient and unstable voltage of the city electricity. 
   Further, sampling and feedback are conducted continuously between each microcontroller  22  and each Hall component  31  to transmit signals to the microcontroller  22 . After the microcontroller  22  computes, processes, and analyzes the signals, the rotary speed of the brushless DC motor  21  required for controlling each driving device  24  is compensated and adjusted, and such continuous and accurate automatic detecting compensation and adjustment of the rotary speed can achieve the stepless speed adjusting effect. 
   Further, the driving device  24  of the invention is a small-capacity bipolar junction transistor (BJT) module or a large-capacity metal oxide semiconductor field effect transistor (MOSFET) module  241  depending on the specification and size of the brushless DC motor  21 . 
   In the meantime, the remote control device  23  adopts the wireless transmission method, and the remote control device could use radio frequency (RF) or infrared (IR) wireless transmissions, which remotely controls the operations of the brushless DC motor  21  of the ceiling fan within a range, and also adjusts and sets the rotary speed. 
   It is worth pointing out that there are three technical measures taken for reducing the power consumption: using a brushless DC motor to replace traditional sensing motors; using a high-efficient high-frequency switching power supply to replace DC power source, and using a passive valley-fill power factor corrector to increase the power factor of the system and minimize the waste of power. 
   Referring to  FIGS. 3 and 4 , the high-frequency switching power supply comprises a power switch Q 2 , a transformer T 1 , a diode D 11 , and an output capacitor C 9 , and the transformer T 1  has the function of a capacitor, and the basic operating principle is to store the energy into the capacitor of a primary TIA of the transformer when the power switch Q 2  is connected electrically, and the energy is sent from the transformer to a secondary TIB when the power switch is disconnected. After the rectification is conducted by the diode D 11  and the filter is conducted by the capacitor C 9 , the power is outputted to the negative load, and thus such arrangement can achieve a conversion efficiency of over 80%, and the output end has an isolating effect, and the output ripples and noises are below 1%. Further, the idle power supply of a high-frequency switching power supply comprises a power integrated circuit U 2 , a transformer T 2 , a diode D 1 , a capacitor  11 , a Zener diode D 19 , and a photocoupler integrated circuit U 3 , and the operating principle is to store the energy into the capacitor of a primary T 2 A of the transformer when the power integrated circuit U 2  is connected electrically, and the energy is sent from the transformer to a secondary T 2 B when the power switch is disconnected. After the energy is sent from the transformer to the secondary T 2 B for the output, and the rectification is conducted by the diode D 1  and the filter is conduced by the capacitor C 11 , the voltage is outputted stably to the negative load, and the Zener diode D 19  and photocoupler integrated circuit U 3  feed back the voltage at the negative load end to the power integrated circuit U 2  to adjust the electric connecting time of the switch and achieve a stable voltage, so as to reduce the idle power supply to 0.47 W while having the over-voltage and over-current protection and antistatic charges functions. 
   Referring to  FIG. 3 , the passive valley-fill power factor corrector comprises a diode D 5 , D 6 , D 7  and a capacitor C 4 , C 5 , and the operating principle is to electrically connect the diode D 6 , disconnect the diodes D 5 , D 7  when the power rectification circuit D 1  is electrically connected, and the power supply stores energy to the capacitors C 4 , C 5  and outputs the power to a negative load. After the capacitors C 4 , C 5  are fully charged, the diodes D 5 , D 6 , D 7  are disconnected, and the power is outputted to the negative load only. When the power rectification circuit D 1  is disconnected, the diodes D 5 , D 7  are electrically connected, the capacitors C 4 , C 5  supplies power to the negative load circuit, such that when the power rectification circuit D 1  is disconnected, the input of electric current remains, so as to lower the distortion of input current and improve the power factor. 
   Referring to  FIG. 5 , another preferred embodiment of the present invention comprises a light adjusting device  60 , a lamp  61  being a light emitting device installed between each power supply  40  and the microcontroller  22 , a control device  62  being a triode for alternating current (TRIAC) for receiving an instruction given by the microcontroller  22  to turn on or off the lamp  61  and produce a trigger voltage to electrically connect the control device  62  and use the trigger angle to obtain a different output power, so as to achieve a linear light adjusting effect and preventing the blinking of light. 
   In summation of the description above, the universal low-power ceiling fan controller in accordance with the present invention uses the microcontroller to control each driving device and brushless DC motor and operate together with the feedback device to achieve stepless linear adjusting constant speed rotations. With the remote control device  23 , the structure of the invention adopts a microcontroller  22  driven by a wireless transmission and a remote control to obtain a stepless adjustment of a constant rotary speed and control a low power consumption of the fan. The structure of the invention herein enhances the performance and overcomes the shortcoming of the prior art, and further complies with the patent application requirements. 
   While the invention has been described by way of example and in terms of a preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.