DESC:TECHNICAL FIELD OF THE INVENTION
[1] The present invention relates to a system and a method for providing real-time filter clean alerts to a user.

BACKGROUD OF THE INVENTION
[2] Generally, an indoor unit typically consists of a condensing coil, a fan blower, and a control board for control actions. Nowadays, there are systems that clean the inflowing air directed towards user. The dust and other particulates are removed by passing the airflow through a filter positioned inside the indoor unit. As the airflow passes through the filter, many particulates in the airflow are trapped within the filter and removed. However, overtime the filter becomes contaminated and clogged with the trapped particulates and requires cleaning or replacement. When the filter is clogged, time taken to cool a room increases, which adversely increases compressor run time, and decreases energy efficiency of system.
[3] Presently available systems provide alert user based on fixed operational time intervals and vague assumptions of clogged filter, effecting efficiency and overall hygiene. Further, the use of external sensors that detect clogged filter has economic disadvantage and associated maintenance costs.
[4] Therefore, there is a need to overcome one or more of the aforementioned problems.

SUMMARY OF THE INVENTION
[5] Accordingly, an aspect of the present invention discloses a method for
providing a real-time filter clean alert, the method comprising the steps of defining and storing, by a microcontroller, a plurality of pre-set fan supply voltage values for corresponding plurality of pre-set fan speed values in a memory; measuring and determining, by a microcontroller, a real-time fan supply voltage value at a real-time fan speed feedback value; comparing, by the microcontroller, said determined real-time fan supply voltage value at said real-time fan speed feedback value with said stored pre-set fan supply voltage value for said stored corresponding pre-set fan speed value; defining and invoking a filter clean alert control signal, by the microcontroller, when said compared real-time fan supply voltage value at real-time fan feedback value is less than said pre-set fan voltage value at a pre-defined filter alert count value, indicating a clogged filter to a user.
[6] According to an embodiment, said real-time fan supply voltage value at said real-time fan speed feedback value is measured at a pre-defined time interval, defined by said microcontroller, during continuous operation of a compressor.
[7] According to the embodiment, said plurality of pre-set fan supply voltage values for corresponding said plurality of pre-set fan speed values is determined at a pre-defined time interval, defined by said microcontroller, after starting of said compressor.
[8] According to the embodiment, the step of defining pre-set fan speed values includes monitoring and varying fan supply voltage values to obtain said pre-set fan speed values.
[9] According to the embodiment, said pre-set fan supply voltage values, said pre-set fan speed values, said pre-defined filter alert count values are determined by the microcontroller.
[10] According to another aspect, the present invention discloses a real-time filter clean alert system comprising a memory configured to store a plurality of pre-set fan supply voltage values for corresponding plurality of pre-set fan speed values; a fan feedback measurement circuit configured to measure a real-time fan supply voltage value at a real-time fan speed value; a microcontroller in communication with the fan feedback measuring circuit and the memory, said microcontroller configured to: receive the measured supply voltage value, calculate a real-time fan speed value based on the received supply voltage value, look-up said pre-set fan supply voltage value for corresponding to pre-set fan speed values from the memory, compare real-time fan supply voltage value at said real-time fan speed feedback value with said stored pre-set fan supply voltage value for said stored corresponding pre-set fan speed value, and invoke a fan clean alert control signal, when said compared real-time fan supply voltage value at real-time fan feedback value is less than said pre-set fan voltage value at a pre-defined filter alert count value, indicating a clogged filter to a user.
[11] According to another embodiment, the microcontroller invokes a control signal to automatically clean the clogged filter after the filter clean alert control signal is triggered.

BRIEF DESCRIPTION OF THE DRAWINGS
[12] The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which:
Figure 1 shows a flow chart of a method for providing a real-time filter clean alert, according to an aspect of the present invention;
Figure 2 shows a logic diagram associated with the method for providing a real-time filter clean alert, according to the aspect of the present invention; and
Figure 3 shows a real-time filter clean alert system according to an aspect of the present invention.
Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure. Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION
[13] In general, the present invention discloses a system and a method for providing real-time filter clean alerts to a user. The real-time filter clean alert system invokes control signals to indicate filter clean alert to the user. The amount of voltage required to maintain the speed of the fan when the filter is clean and when the filter is clogged is different. The system measures real-time RPM (rotations per minute) of the fan at respective real-time supply voltage to fan motor and based on measured value it provides a fan feedback that controls supply voltage to the fan motor. When the filter is clogged, there is a significant change in supply voltage to the fan motor in order to maintain desired RPM level of the fan. The system is configured to determine any significant change in supply voltage and thereby invokes a filter clean alert to the user. The system determines different fan control voltage levels and controls operation of filter clean system to indicate whether the filter is clogged or not. Therefore, precise, timely and accurate alert control signals are invoked to indicate clogging filter in an indoor unit. This by way of exemplary implementation maintains operational efficiency of HVAC system and overall hygiene factor.
[14] According to the present invention, the voltage to the fan motor is controlled through a fan feedback measurement. Real-time speed RPM of the fan motor at respective real-time supply voltage to motor is provided as feedback. Therefore, real-time voltage provided to the fan motor is controlled and regulated to achieve desired fan speed. Due to the blockage of filter, the supply voltage to the motor changes to maintain the desired RPM level. When a significant change in voltage level is observed, the system declares the filter clean alert to the user.
[15] According to an aspect, the present invention discloses a method for providing a real-time filter clean alert, the method comprising the steps of: defining and storing, by a microcontroller, a plurality of pre-set fan supply voltage values for corresponding plurality of pre-set fan speed values in a memory; measuring and determining, by the microcontroller, a real-time fan supply voltage value at a real-time fan speed feedback value; comparing, by the microcontroller, said determined real-time fan supply voltage value at said real-time fan speed feedback value with said stored pre-set fan supply voltage value for said stored corresponding pre-set fan speed value; defining and invoking a filter clean alert control signal, by the microcontroller, when said compared real-time fan supply voltage value at real-time fan feedback value is less than said pre-set fan voltage value at a pre-defined filter alert count value, indicating a clogged filter to a user.
[16] According to another aspect, the present invention discloses a real-time filter clean alert system comprising: a memory configured to store a plurality of pre-set fan supply voltage values for corresponding plurality of pre-set fan speed values; a fan feedback measurement circuit configured to measure a real-time fan supply voltage value at a real-time fan speed value; a microcontroller in communication with the fan feedback measuring circuit and the memory, said microcontroller configured to: receive the measured supply voltage value, calculate a real-time fan speed value based on the received supply voltage value, look-up said pre-set fan supply voltage value for corresponding to pre-set fan speed values from the memory, compare real-time fan supply voltage value at said real-time fan speed feedback value with said stored pre-set fan supply voltage value for said stored corresponding pre-set fan speed value, and invoke a fan clean alert control signal, when said compared real-time fan supply voltage value at real-time fan feedback value is less than said pre-set fan voltage value at a pre-defined filter alert count value, indicating a clogged filter to a user.
[17] Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.
[18] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
[19] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
[20] Figures discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way that would limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged environment. The terms used to describe various embodiments are exemplary. It should be understood that these are provided to merely aid the understanding of the description, and that their use and definitions in no way limit the scope of the invention.
[21] Referring Figures 1-3 show a real-time filter clean alert system (300) and a method (100, 200) for providing real-time filter clean alert. The system (300) includes a real-time filter clean alert unit (310) having an input/output unit (320), a microcontroller (330), a fan feedback measurement circuit (340), a processor (350), a memory (360) in communication with each other. A fan (390), a compressor (395), an output device (370) and input device (380) in communication with the filter clean alert unit (310).
[22] According to the present invention, pre-set fan supply voltage values and pre-set fan speed values are determined by microcontroller. Pre-set fan supply voltage value is defined as ideal/initial voltage supplied to rotate fan motor at ideal /desired speed when the filter is not clogged after start of the compressor.
[23] According to the present invention, pre-defined time interval is defined as the time interval after start of the compressor or during continuous running of the compressor at which the microcontroller is configured to measure or determine the values of speed and voltage.
[24] According to the present invention, pre-defined filter alert count value is defined as the percentage of clean filter or percentage of clogged filter after which the microcontroller invokes a user alter.
[25] Referring Figure 1 shows a flow chart of a method (100) for providing a real-time filter clean alert, according to an aspect of the present invention. The method comprises the steps of: (110) defining and storing, by a microcontroller (330), a plurality of pre-set fan supply voltage values for corresponding plurality of pre-set fan speed values in a memory (360); (120) measuring and determining, by the microcontroller (330), a real-time fan supply voltage value at a real-time fan speed feedback value; (130) comparing, by the microcontroller (330), said determined real-time fan supply voltage value at said real-time fan speed feedback value with said stored pre-set fan supply voltage value for said stored corresponding pre-set fan speed value; (140) defining and invoking a filter clean alert control signal, by the microcontroller (330), when said compared real-time fan supply voltage value at real-time fan feedback value is less than said pre-set fan voltage value at a pre-defined filter alert count value, indicating a clogged filter to a user.
[26] According to an embodiment, the method (100) includes the step of measuring said real-time fan supply voltage value at said real-time fan speed feedback value measured at a pre-defined time interval, defined by said microcontroller (330), during continuous operation of a compressor (395).
[27] According to the embodiment, said plurality of pre-set fan supply voltage values for corresponding said plurality of pre-set fan speed values is determined at a pre-defined time interval, defined by said microcontroller (330), after starting of said compressor (395).
[28] According to the embodiment, the step of (110) defining pre-set fan speed values includes monitoring and varying fan supply voltage values to obtain said pre-set fan speed values.
[29] According to the embodiment, said pre-set fan supply voltage values, said pre-set fan speed values, said pre-defined filter alert count values are determined by the microcontroller (330).
[30] Referring Figure 2 and 3, shows a logic diagram associated with the method for providing a real-time filter clean alert and a real-time filter clean alert system (300), according to the aspect of the present invention. The logic is explained by an exemplary implementation of said filter clean alert system (300) in a heating, ventilation and air conditioning (HVAC) system in the following way: when the HVAC system is starting it is said to be in a normal mode and the microcontroller checks, if the first pre-defined time period since the HVAC system has been activated or power up time is reached after compressor startup and if reached HVAC system is said to powered up as indicated in step (201) and then proceeds to step (202). The HVAC system is said to be powered up in first pre-defined time period about 500 milliseconds. The pre-defined time period is determined by the microcontroller.
[31] As shown in step (202), when the HVAC system is powered up, the microcontroller (330) is configured to determine real-time fan motor supply voltage values i.e. fan control PWM duty values for one or more desired fan motor revolution per minute (RPM) values i.e. low speed, mid speed and high speed values. The microcontroller reads the pre-set values which are stored in memory (360) of the filter clean alert system (300) and then proceeds to step (203).
[32] As shown in step (203), the microcontroller (330) determines if the determined fan control PWM duty values are == 0 or FF and if fan control PWM duty values are not equal to 0 or FF that it proceeds to step (218) or it proceeds to step 204.
[33] As shown in step (204), the microcontroller (330) is configured to make first time flags for low speed, mid speed and high-speed set. Accordingly, the microcontroller performs control operation to obtain ideal fan control PWM duty cycle count and then proceed to step (205).
[34] As shown in step (205), the microcontroller (330) is configured to set a low fan speed then proceed to step (206). In step (206), the microcontroller (330) determines if desired speed (RPM) is achieved, if achieved it proceeds to step (208) or it proceeds to step (207). In step (207), the microcontroller (330) varies the fan control PWM duty cycle to achieve the desired speed (RPM) at low speed and then proceed to step (206). When it is determined again in step (206) that the desired speed (RPM) at low speed is achieved, the values are then stored as low fan speed base value in Erasable Programmable Read-Only Memory (EEPROM) (360) of the filter clean alert system (300) and then proceed to step (209). According to an exemplary implementation of the filter clean alert system, the pre-defined time interval for determining by the microcontroller if the desired low speed RPM is reached is about 3 seconds.
[35] As shown in step (209), the microcontroller (330) is configured to set a medium fan speed then proceed to step (210). In step (210), the microcontroller (330) determines if desired speed (RPM) is achieved, if achieved it proceeds to step (212) or it proceeds to step (211). In step (211), the microcontroller (330) varies the fan control PWM duty cycle to achieve the desired speed (RPM) at medium speed and then proceed to step (212). When it is determined again in step (212) that the desired speed (RPM) at medium speed is achieved, the values are then stored as medium fan speed base value in Erasable Programmable Read-Only Memory (360) (EEPROM) of the filter clean alert system (300) and then proceed to step (213). According to an exemplary implementation of the filter clean alert system (300), the pre-defined time interval for determining by the microcontroller (330) if the desired medium RPM is reached is about 3 seconds.
[36] As shown in step (213), the microcontroller (330) is configured to set a high fan speed then proceed to step (214). In step (213), the microcontroller (330) determines if desired RPM is achieved, if achieved it proceeds to step (216) or it proceeds to step (215). In step (215), the microcontroller (330) varies the fan control PWM duty cycle to achieve the desired RPM at high speed and then proceed to step (216). When it is determined again in step (216) that the desired RPM at high speed is achieved, the values are then stored as high fan speed base value in Erasable Programmable Read-Only Memory (360) (EEPROM) of the filter clean alert system (300) and then proceed to step (217). According to an exemplary implementation of the filter clean alert system (300), the pre-defined time interval for determining, by the microcontroller if the desired high RPM is reached is about 3 seconds.
[37] As shown in step 217, microcontroller (330) assigns first flag to each of low, mid and high-speed base and then proceeds to step (218).
[38] As shown in step (218), the user is asked by the microcontroller (330) to set the desired fan speed and the proceed to step (219). In step (219), according to an exemplary implementation of the filter clean alert system (300), the microcontroller (330) waits for a pre-defined time interval of about 5 minutes for stabilizing the fan speed and then proceed to step (220).
[39] As shown in step (220), the microcontroller (330) measures a real-time fan motor feedback RPM value obtained from the feedback circuit (330) for each of said determined real-time fan motor supply voltage value at said determined fan motor revolution per minute (RPM) value. The microcontroller stores the values obtained in the memory (360) and then proceeds to step (221).
[40] As shown in step (221), the microcontroller (330) compares obtained and stored real-time fan motor supply voltage value at real-time fan motor feedback RPM value with a pre-defined/ pre-set fan motor supply voltage value at pre-defined/pre-set fan motor RPM value and then proceeds to step (222). In step (222), the microcontroller determines if the desired obtained real-time fan motor feedback RPM value is within range of actual base fan motor feedback RPM value at different speeds, if the value is within range then proceed to step (224) or proceed to step (223). In step (223) if the obtained value is not within the range, then the microcontroller varies the fan control PWM cycle to obtain the desired range and then proceed to step (224).
[41] A shown in step (224), the microcontroller (330) determines if the value obtained when real-time fan control duty when subtracted from base fan control duty i.e. the compared real-time fan supply voltage value at real-time fan motor feedback RPM value is less than a pre-defined/pre-set fan voltage value at a pre-defined filter alert count value, if lesser proceed to step (225) or to return to step (222). According to the embodiment, the microcontroller determines the filter clean alert count.
[42] As shown in step (225), the microcontroller (330) defines and invokes a filter clean alert control signal, for indicating a clogged filter to a user, and thus maintains and controls operational efficiency of the HVAC system and then proceed to step (226). In step (226) the microcontroller resets the invoked filter alert after the user cleans the filter. According to the embodiment, the microcontroller invokes a control signal to automatically clean the clogged filter after the filter clean alert control signal is triggered. The filter can also be clean manually by the user.
[43] Referring Figure 3 shows a real-time filter clean alert system (300) according to an aspect of the present invention. The filter clean alert system (300) includes a real-time filter clean alert unit (310), an input/output unit (320), a microcontroller (330), a fan feedback measurement circuit (340), a processor (350), a memory (360) in communication with each other. A fan (390), a compressor (395), an output device (370) and input device (380) in communication with the filter clean alert unit (310).
[44] According to the embodiment, after staring the compressor (395), the input/output unit (320) in communication with input device (380) receives user input and thereby sets low speed, mid speed and high-speed values. The speed values and their corresponding fan voltages values are stored in the memory (360). The fan feedback measurement circuit (340) in communication with microcontroller (330) is configured to compared real time fan voltages and corresponding speed values with pre-set fan voltages and speed values. When the microcontroller determines that the real time fan voltages and speed values are less than pre-set fan voltage value at a pre-defined filter alert count value, microcontroller alerts the user indicating a clogged filter.
[45] Example 1:
[46] According to an exemplary implementation of the present filter clean alert system of a HVAC system shown the following results for:
LOW SPEED (TABLE 1)
Filter Low Speed firing angle count to control the AC voltage Measured Low Fan Speed Count
With clean filter 474 846
When compressor starts 465 845
Type 1 clogged filter with compressor off 494 845 20
Type 1 clogged filter with compressor on 480 846 6
Type 2 clogged filter with compressor off 532 850 58
Type 2 clogged filter with compressor on 518 863 44

[47] According to an exemplary implementation of the present filter clean alert system of a HVAC system at low speed. Table 1 shows two types of clogged filters compared with clean filter in two situations i.e. when compressor is ON and OFF. As seen from the table it is clear that the filter alert count is increasing as the dirt is getting clogged on the filter. Further, it can be clearly observed that the voltage required to maintain the desired RPM changes as the filter gets clogged i.e. the fan voltage is less. At a desired filter alert count, as pre-defined by the controller, by way of example, but not limited to about 70% of clean value the microcontroller invokes a control signal to send filter clean alert to the user.

MEDIUM SPEED (TABLE 2)
Filter Medium Speed firing angle count to control the AC voltage Measured medium Fan Speed Count
With clean filter 449 946
When compressor starts 440 952
Type 1 clogged filter with compressor off 472 946 23
Type 1 clogged filter with compressor on 458 940 9
Type 2 clogged filter with compressor off 512 952 63
Type 2 clogged filter with compressor on 506 941 57

[48] According to an exemplary implementation of the present filter clean alert system of a HVAC system at medium speed. Table 2 shows two types of clogged filters compared with clean filter in two situations i.e. when compressor is ON and OFF. As seen from the table it is clear that the filter alert count is increasing as the dirt is getting clogged on the filter. Further, it can be clearly observed that the voltage required to maintain the desired RPM changes as the filter gets clogged. i.e. the fan voltage is less. At a desired filter alert count, as pre-defined by the microcontroller, by way of example, but not limited to about 70% of clean value the microcontroller invokes a control signal to send filter clean alert to the user.
HIGH SPEED (TABLE 3)
Filter High Speed firing angle count to control the AC voltage Measured high Fan Speed Count
With clean filter 397 1207
When compressor starts 385 1205
Type 1 clogged filter with compressor off 434 1190 37
Type 1 clogged filter with compressor on 417 1199 20
Type 2 clogged filter with compressor off 487 1199 90
Type 2 clogged filter with compressor on 478 1190 81

[49] According to an exemplary implementation of the present filter clean alert system of a HVAC system at high speed. Table 3 shows two types of clogged filters compared with clean filter in two situations i.e. when compressor is ON and OFF. As seen from the table it is clear that the filter alert count is increasing as the dirt is getting clogged on the filter. Further, it can be clearly observed that the voltage required to maintain the desired RPM changes as the filter gets clogged i.e. the fan voltage is less. At a desired filter alert count, as pre-defined by the microcontroller, by way of example, but not limited to about 70% of clean value the microcontroller invokes a control signal to send filter clean alert to the user.
[50] According to an exemplary implementation, the present invention discloses a TRIAC based speed control mechanism for AC motor. A TRIAC is a three-terminal device for controlling current. Controlling mechanism is based on phase angle adjustment. The gate triggering pulse to the TRIAC are controlled from the microcontroller by providing PWM pulses. The duty cycle of these PWM pulses are controlled to control the fan control voltage. In a positive half cycle, TRIAC is turned ON after some delay and after zero crossing detection. TRIAC automatically turns off when the current reaches a zero value. In negative half cycle, again the TRIAC is triggered after some delay. The relation between PWM Duty Cycle Count Value and Fan Control Voltage is inversely proportional. When the PWM duty cycle count is less, the fan control voltage is more and in case of a clogged filter high PWM duty cycle count is required to maintain the fan at desired speed, which decreased the fan control voltage. Therefore, when the filter is clogged the fan control voltage decreases.
[51] The present invention has been described in the context of a system and method for providing a filter clean alert to a user. The control logic is based on determining the voltage of the fan and comparing it with a pre-defined voltage value thereby indicating that voltage is needed to drive the fan motor at desired RPM changes and is less when the filter is clogged. The microcontroller send a clean alert to the user. Accordingly, it should be apparent to those skilled in the art that the following description of HVAC system referred in the description for the purpose of the understanding and nowhere limit the invention and filter clean alert system disclosed in the present invention can be adapted to an Air-conditioning system, a Variable refrigerant flow (VRF) system and the like as well. The present invention is not limited to the numerals, percentages, pre-defined time intervals as described above and are shown as exemplary implementations. Accordingly, as per operational requirements the values may change and are within the scope of the present invention.
[52] In the foregoing detailed description of aspects embodiments of the invention, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments of the invention require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus, the following claims are hereby incorporated into the detailed description of aspects, embodiments of the invention, with each claim standing on its own as a separate embodiment.
[53] It is understood that the above description is intended to be illustrative, and not restrictive. It is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined in the appended claims. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” is used as the plain-English equivalent of the respective term “comprising” respectively.

,CLAIMS:
1. A method for providing a real-time filter clean alert, comprising the steps of:
defining and storing, by a microcontroller, a plurality of pre-set fan supply voltage values for corresponding plurality of pre-set fan speed values in a memory;
measuring and determining, by the microcontroller, a real-time fan supply voltage value at a real-time fan speed feedback value;
comparing, by the microcontroller, said determined real-time fan supply voltage value at said real-time fan speed feedback value with said stored pre-set fan supply voltage value for said stored corresponding pre-set fan speed value;
defining and invoking a filter clean alert control signal, by the microcontroller, when said compared real-time fan supply voltage value at real-time fan feedback value is lesser than said pre-set fan voltage value at a pre-defined filter alert count value, indicating a clogged filter to a user.

2. The method as claimed in claim 1, wherein said real-time fan supply voltage value at said real-time fan speed feedback value is measured at a pre-defined time interval, defined by said microcontroller, during continuous operation of a compressor.

3. The method as claimed in claims 1-2, wherein said plurality of pre-set fan supply voltage values for corresponding said plurality of pre-set fan speed values is determined at a pre-defined time interval, defined by said microcontroller, after starting of said compressor.

4. The method as claimed in claims 1-3, wherein the step of defining pre-set fan speed values includes monitoring and varying fan supply voltage values to obtain said pre-set fan speed values.

5. The method as claimed in claims 1-4, wherein said pre-set fan supply voltage values, said pre-set fan speed values, said pre-defined filter alert count values are determined by the microcontroller.

6. A real-time filter clean alert system comprising:
a memory configured to store a plurality of pre-set fan supply voltage values for corresponding plurality of pre-set fan speed values;
a fan feedback measurement circuit configured to measure a real-time fan supply voltage value at a real-time fan speed value;
a microcontroller in communication with the fan feedback measuring circuit and the memory, said microcontroller configured to:
receive the measured supply voltage value,
calculate a real-time fan speed value based on the received supply voltage value,
look-up said pre-set fan supply voltage value for corresponding to pre-set fan speed values from the memory,
compare real-time fan supply voltage value at said real-time fan speed feedback value with said stored pre-set fan supply voltage value for said stored corresponding pre-set fan speed value, and
invoke a fan clean alert control signal, when said compared real-time fan supply voltage value at real-time fan feedback value is lesser than said pre-set fan voltage value at a pre-defined filter alert count value, indicating a clogged filter to a user.

7. The system as claimed in claim 6, wherein the microcontroller invokes a control signal to automatically clean the clogged filter after the filter clean alert control signal is triggered.