Abstract:
A driving controlling apparatus of a hood motor, including: hood motor means rotatably driven for ventilating the inner portion of a system; main controlling means for generating control signals for controlling the operation of the hood motor; sub-controlling means for controlling the driving of the hood motor by sensing temperature changes in the system; and driving circuit means for controlling the driving of the hood motor in accordance with the control signal of the main controlling means and the driving controlling of the sub-controlling means.

Description:
CLAIM OF PRIORITY 
     This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application for SAFETY CONTROL APPARATUS FOR A HOOD MOTOR earlier filed in the Korean Industrial Property Office on Aug. 20, 1999 and there duly assigned Ser. No. 34659/1999. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a hood motor of a gas range, and more particulary to a driving controlling apparatus of a hood motor for switching on/off the driving of the hood motor and for controlling the rotational speed of a hood motor. 
     2. Description of the Related Art 
     Generally, a hood motor ventilates hot-air generated from the lower side of a gas range, and the odor of foods being cooked. Such a hood motor includes a driving controlling apparatus for starting/stopping the driving of the motor, and for controlling the rotational speed of the motor by using a temperature sensor installed therein for sensing the temperature rise. 
     FIG. 1 is a circuit diagram for showing a conventional driving controlling apparatus of a hood motor. 
     As shown in FIG. 1, the conventional driving controlling apparatus of the hood motor includes a hood motor  1 , a thermal cut out (hereinafter called TCO), a motor driving relay  2 , and a motor rotational speed switching relay  3 . 
     The hood motor  1  includes a temperature protector (hereinafter called T/P), inductors L 1 , L 2 , and L 3 , and a capacitor C. Between the inductors L 2  and L 3  of the hood motor  1 , a low-velocity transfer contact L of the motor rotational speed switching relay  3  is connected, while a high-speed transfer contact H is connected between the inductors L 1  and L 3  of the motor rotational speed switching relay  3 . 
     Further, the motor driving relay  2  includes an exciting coil which is connected with a motor driving button, while both ends of the TCO are connected with a switching terminal T 1  and a switching-on contact, respectively. 
     The exciting coil of the motor rotational speed switching relay  3  is connected with a speed switching button which is manipulated by a user, while another switching terminal T 2  is connected with the switching-on contact of the motor driving relay  2 . 
     In the driving controlling apparatus of the hood motor constructed as above, when the user wants to ventilate the gas range, the user manipulates the motor driving button to connect the switching terminal T 1  of the motor driving relay  2  to the switching-on contact. Accordingly, commonly used alternating current (hereinafter called AC power) is applied to the hood motor  1 , so that the hood motor  1  is rotatably driven. 
     In such a situation, when the user manipulates the speed switching button, the motor rotational speed switching relay  3  varies the rotational speed of the hood motor  1 , in accordance with the contact of the switching terminal T 2  with the low-velocity transfer contact L or with the highvelocity transfer contact H, by the selective manipulation of the user through the speed switching button. 
     Meanwhile, when the temperature in the gas range rises over a certain temperature, the TCO which senses such a temperature rise is switched on. Accordingly, the hood motor  1  is rotatably driven by AC power due to a closed circuit formed by the TCO, even when the switching terminal T 1  of the motor driving relay  2  is not switched on to the switching-on contact. 
     In such a situation, also, the rotational speed of the hood motor  1  is adjusted by the user who manipulates the speed switching button by selectively switching the motor rotational speed switching relay  3 . 
     In the conventional driving controlling apparatus of the hood motor, however, since expensive relays have to be employed to switch on/off the hood motor and to control the rotational speed of the hood motor, the manufacturing cost is considerably higher. Further, as the relays are frequently used, there occurs poor contact of the relays, so that the driving reliability of the circuit is deteriorated. 
     Accordingly, there is a growing demand for a driving controlling apparatus that can substitute the conventional hood motor driving method employing expensive relays, which is inexpensive, and has higher reliability. 
     SUMMARY OF THE INVENTION 
     The present invention has been developed to overcome the above-mentioned problems of the related art, and accordingly, it is an object of the present invention to provide a driving controlling apparatus of a hood motor capable of on/off driving the hood motor and controlling the rotational speed of the hood motor without employing expensive relays, by the pulse width modulation controlling of a microcomputer. 
     Another object of the present invention is to provide a driving controlling apparatus of a hood motor capable of on/off driving the hood motor by sensing a temperature rise in a gas range even without a pulse width modulation controlling of a microcomputer. 
     The above objects are accomplished by a driving controlling apparatus of a hood motor according to the present invention, including: hood motor means rotatably driven for ventilating the inner portion of a system; main controlling means for generating control signals for controlling the operation of the hood motor, sub-controlling means for controlling the driving of the hood motor by sensing temperature change in the system; and driving circuit means for controlling the driving of the hood motor in accordance with the control signal of the main controlling means and the driving controlling of the sub-controlling means. 
     Preferably, the main controlling means generates control signals for on/off driving the hood motor, and for controlling the switching of the rotational speed of the hood motor. 
     More preferably, the main controlling means includes: a microcomputer for outputting pulse width modulation control signals of varied duty cycle in accordance with a low-speed mode and a high-speed mode; and a transistor on/off driven by the pulse width modulation control signals from the microcomputer, for generating pulse signals. 
     Further, the sub-controlling means includes: a printed circuit board power circuit for generating a certain driving voltage; a voltage dividing circuit for dividing a certain driving voltage from the printed circuit board power circuit; and a temperature switch for sensing a temperature rise of the inner portion of the system to a certain degree, the temperature switch being switched on/off for applying the partial voltage divided by the voltage dividing circuit into the driving circuit means. 
     Further, the driving circuit means includes: a switching regulator for outputting driving pulse signals of a certain frequency by pulse signals applied from a transistor of the controlling means; and a transistor driven by the driving pulse signals from the switching regulator for controlling the applying of direct current power to the hood motor from the rectifier circuit means. 
     In a driving controlling apparatus of a hood motor constructed as above according to the present invention, since inexpensive transistors are employed to on/off drive the hood motor and to control the rotational speed of the hood motor, instead of the conventionally-used expensive relays, the manufacturing cost is significantly reduced. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A more complete appreciation of the invention, and many of the attendant advantages thereof, will be readily apparent as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference symbols indicate the same or similar components, wherein: 
     FIG. 1 is a circuit diagram for showing a conventional driving controlling apparatus of a hood motor; 
     FIG. 2 is a circuit diagram for showing a driving controlling apparatus of a hood motor according to a first preferred embodiment of the present invention; and 
     FIG. 3 is a circuit diagram for showing a driving controlling apparatus of a hood motor according to a second preferred embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Hereinafter, the preferred embodiment of the present invention will be described in greater detail with reference to the accompanied drawings, while the like elements are referred to by the same reference numerals throughout. 
     The main feature of the first preferred embodiment of the present invention is that the rotational speed of a hood motor is controlled by controlling a switching time of a transistor, which is performed by varying a duty cycle of a pulse width modulation (hereinafter called PWM) generated from a microcomputer. Further, according to the first preferred embodiment of the present invention, when there is temperature rise in the gas range, a temperature sensor which senses such a temperature rise is switched on, to thereby drive the hood motor by direct current (hereinafter called DC power) from a power circuit of a printed circuit board (hereinafter called PCB). 
     FIG. 2 shows the driving controlling apparatus of the hood motor according to the first preferred embodiment of the present invention. 
     As shown in FIG. 2, the driving controlling apparatus of the hood motor according to the first preferred embodiment of the present invention includes a rectifier circuit section  10 , a motor driving button  11 , a speed switching button  12 , a first driving controlling section  20 , a driving circuit section  30 , a second driving controlling section  40 , and a hood motor M. 
     The rectifier circuit section  10  includes a bridge diode B/D for full-wave rectifying the AC power, and a smoothing capacitor C 1  for smoothing the voltage which is full-wave rectified. 
     The first driving controlling section  20  includes a microcomputer  21  connected with the motor driving button  11  and the speed switching button  12 , and having a PWM port, and a ground terminal GND, and a first transistor Q 1  having abase electrode connected with the PWM port of the microcomputer  21 , and a collector electrode connected with the driving circuit section  30 . 
     The microcomputer  21  outputs PWM control signals for on/off driving the hood motor M and for controlling the rotational speed of the hood motor M by the manipulation of the motor driving button  11  and the speed switching button  12 . The first transistor Q 1  outputs the pulse signals which are phase-inverted through the collector electrode thereof by being driven by the PWM control signals applied from the microcomputer  21 . 
     Here, the microcomputer  21  outputs the PWM control signal having a duty cycle corresponding to a predetermined rotational speed when there is a button manipulation of the motor driving button  11 . 
     Further, when the low-velocity mode is selected by the button manipulation of the speed switching button  12 , the microcomputer  21  outputs the PWM control signal of a certain frequency such as the frequency of 4KHz having a small duty cycle. Then when the high-speed mode is selected by the button manipulation through the speed switching button  12 , the microcomputer  21  outputs the PWM control signal having the same frequency with the low-speed mode such as the frequency of 4KHz, but with a larger duty cycle. 
     Meanwhile, the microcomputer used for controlling the general functions of the gas range may be used as the microcomputer  21 , or there may be an additional microcomputer for specifically controlling the driving of the hood motor M in addition to the microcomputer of the gas range. 
     Further, the driving circuit section  30  includes a switching regulator  31 , and a second transistor Q 2 . A signal input port of the switching regulator  31  is connected with a collector electrode of the first transistor Q 1  and the second driving controlling section  40 . A collector electrode of the second transistor Q 2  is connected with one end of the hood motor M, while an emitter electrode is connected with the smoothing capacitor C 1  and the bridge diode B/D. 
     The switching regulator  31  generates a driving pulse signal having the same duty cycle with the PWM control signal, but with a higher frequency such as 20 KHz, with the pulse signals applied from the collector electrode of the first transistor Q 1 . 
     The second transistor Q 2  on/off controls the hood motor M, and also controls the rotational speed of the hood motor M, by being driven by the driving pulse signal applied to the base electrode thereof from the switching regulator  31 . 
     Further, the power circuit, i.e., the second driving section  40  includes a PCB power circuit  41  having a plurality of circuit elements mounted on the PCB of the gas range, for supplying the DC power of a certain voltage such as the voltage of 5V, a plurality of voltage dividing resistors R 2  and R 3  connected in series between the power output port and the ground end of the PCT power circuit  41 , and a TCO connected with the signal input port of the switching regulator  31 . 
     A plurality of voltage dividing resistors R 2  and R 3  divide a certain DC voltage such as 5V from the PCB power circuit  41 , for applying the voltage that falls into a certain voltage range such as the voltage range of 0.7V-3V for driving the driving circuit section  30 . 
     The TCO is disposed at the lower side of the gas range, and is switched on upon sensing a temperature rise to a certain degree in the gas range. 
     Here, the undesignated reference symbol D 1  refers to a diode for protecting the hood motor M by bypassing overcurrent flowing to the hood motor M, in a manner that the diode D 1  is turned on when the voltage applied to the hood motor M rises to a certain voltage. 
     Hereinafter, the operation of the driving controlling apparatus of the hood motor constructed as above according to the first preferred embodiment of the present invention will be described with reference to FIG.  2 . 
     First, the commonly used AC power supplied from the outside is full-wave rectified by the bridge diode B/D of the rectifier circuit section  10 , and is smoothed by the smoothing capacitor C 1  to be supplied to the hood motor M in the form of DC power. 
     In such a situation, when the motor driving button  11  is manipulated for driving the hood motor M, the microcomputer  21  generates the PWM control signal having a certain duty cycle through the PWM output port in accordance with the button manipulation of the motor driving button  11 . 
     The first transistor Q 1  generates the pulse signal which is phase-inverted through the collector electrode thereof, while being on/off driven in accordance with the duty cycle of the PWM control signal which is applied to the base electrode thereof. 
     While the first transistor Q 1  is driven, a certain DC power such as the DC voltage of 5V is dropped by the resistor R 1  into a lower DC power such as the voltage of 3V, and is generated in the form of a pulse signal through the collector electrode thereof. 
     Accordingly, the switching regulator  31  of the driving circuit section  30  receives the pulse signal from the collector electrode of the first transistor Q 1 , and outputs the driving pulse signal having a higher frequency than the PWM control signal such as the frequency of 20 KHz. 
     Accordingly, the second transistor T 2  of the driving circuit section  30  is on/off driven in accordance with the duty cycle of the driving pulse signal which is applied to the base electrode thereof from the switching regulator  31 . The hood motor M is rotated at a certain speed by the DC power applied from the rectifier circuit section  10  in accordance with the on/off driving of the second transistor Q 2 . 
     Meanwhile, when the high-speed mode is selected by the button manipulation of the speed switching button  12 , the microcomputer  21  outputs the PWM control signal having a larger duty cycle through the PWM signal output port in accordance with the button manipulation of the speed switching button  12 . 
     Accordingly, as the duty cycle of the PWM control signal generated from the microcomputer  21  becomes larger, the pulse width of the PWM signal from the collector electrode of the first transistor Q 1  is increased. 
     Accordingly, the pulse width of the driving pulse signal generated from the switching regulator  31  is increased to correspond to the pulse signal generated from the collector electrode of the first transistor Q 1 . The driving time of the second transistor Q 2  is also increased as much as the pulse width increase of the driving pulse signal of the switching regulator  31 . 
     As a result, the hood motor M is rotated at a higher speed by the electric current applied from the rectifier circuit section  10 . 
     Meanwhile, when the low-speed mode is selected by the button manipulation of the speed switching button  12 , the microcomputer  21  outputs the PWM control signal having a smaller duty cycle to correspond to the low-speed mode. The first transistor Q 1  generates the pulse signal having a reduced pulse width to correspond to the smaller duty cycle of the PWM control signal. 
     Accordingly, the switching regulator  31  generates the driving pulse signal having the reduced pulse width to correspond to the pulse signal of reduced pulse width from the first transistor Q 1 . Also, the driving time of the second transistor Q 2  is reduced as much as the pulse width reduction of the driving pulse signal. 
     As the driving time of the second transistor Q 2  is reduced, the electric current applied from the rectifier circuit section  10  is reduced, so that the hood motor M is rotated at a lower speed. 
     Meanwhile, there may be a case when the motor driving button  11  and the speed switching button  12  are not manipulated, so that the microcomputer  21  is not operated while the temperature in the gas range is increased. Also, even though the motor driving button  11  and the speed switching button  12  are correctly manipulated, there may be a case when the PWM control signal is not generated due to the malfunction of the microcomputer  21 , and the temperature in the gas range is increased. In such cases, the TCO of the second driving controlling section  40  senses the temperature rise to a certain degree and is accordingly switched on. 
     As the TCO is switched on, the voltage signal of the partial voltage of a certain degree such as 3V, which is the divided voltage from the certain voltage generated from the PCB power circuit  41  such as the voltage of 5V by the voltage dividing resistors R 2  and R 3 , is inputted to the switching regulator  31  through the TCO. 
     The switching regulator  31  generates the driving pulse signal having the same pulse width as the low-speed mode, with a certain frequency such as the frequency of 20 KHz with the voltage signal applied from the second driving controlling section  40 . 
     The second transistor Q 2  rotates the hood motor M by being on/off driven by the driving pulse signal applied from the switching regulator  31 . 
     Next, the driving controlling apparatus of the hood motor according to the second preferred embodiment will be described below with the accompanying drawings. 
     FIG. 3 is a circuit diagram for showing the driving controlling apparatus of the hood motor according to the second preferred embodiment of the present invention. 
     As shown in FIG. 3, in the description of the second preferred embodiment, the description of the rectifier circuit section  10 , the first driving controlling section  20 , and the driving circuit section  30  will be omitted since they have the same construction as described above in the first preferred embodiment. 
     The unique feature of the second preferred embodiment of the present invention lies in the point where the output voltage from the second driving controlling section  40  is applied to the driving circuit section  30 . 
     That is, according to the first preferred embodiment of the present invention, the partial voltage from the PCB power circuit  41  through the TCO, is applied to the signal input port of the switching regulator  31 . 
     Meanwhile, according to the second preferred embodiment of the present invention, the partial voltage from the PCB power circuit  41  through the TCO is directly applied to the second transistor Q 2  of the driving circuit section  30 . 
     With the partial voltage applied from the second driving controlling section  40  to the base electrode thereof, the second transistor Q 2  keeps being driven. 
     Accordingly, the hood motor M is rotated at a high speed by the electric current constantly applied from the rectifier circuit section  10  in accordance with the constant driving of the second transistor Q 2 . 
     As described above, according to the present invention, the driving controlling apparatus of the hood motor according to the present invention employs inexpensive transistors instead of the expensive relays to on/off drive the hood motor, and to control the rotational speed of the hood motor by controlling the PWM with the microcomputer. Accordingly, the manufacturing cost is reduced, while the reliability of the circuit is improved. 
     While the present invention has been particularly shown and described with reference to the preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be effected therein without departing from the spirit and scope of the invention as defined by the appended claims.