FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003
COMPLETE SPECIFICATION
(See Section 10 and Rule 13)
A BRUSHLESS DIRECT CURRENT (BLDC)
MOTOR
APPLICANT:
CG POWER AND INDUSTRIAL SOLUTIONS LIMITED
AN INDIAN EDUCATIONAL INSTITUTE HAVING ADDRESS AT 6th FLOOR, CG HOUSE, DR A. B. ROAD, WORLI, MUMBAI –
400030, MH, INDIA
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

TECHNICAL FIELD
[001] The present invention relates generally to a brushless direct current (BLDC) motor and more specifically to a BLDC motor for fans.
BACKGROUND
[002] Typically, brushless direct current (BLDC) motors are electric direct current (DC) motors that work without brushes. These motors are generally used in various fields, such as, aircrafts, home appliances, electric vehicles, and the like. In a BLDC motor, an electronic sensor detects an angle of a rotor and controls semiconductor switches through the windings. The major advantage of using the BLDC motors is that these motors provide higher speed and efficiency over conventional brushed direct current motors.
[003] However, the fans having an induction motor are big in size and thus heavier. Due to the size and weight, it is very difficult to install and maintain the fans. Further, it increases the cost as well. Currently, the BLDC motor is used in 400 (mm) sweep and 450 mm sweep fans. The induction fans are used for 600 mm sweep fans for a wall mount application. These fans have high power consumption and 1400 revolutions per minute (rpm) with air delivery of 270 cubic meter per minute (CMM).
[004] Hence, there is a need of a BLDC motor which overcomes the above limitations.
SUMMARY
[004] Embodiments of the present disclosure present technological improvements as solutions to one or more of the above-mentioned technical problems.

[005] Before the present subject matter relating to a brushless direct current (BLDC) motor, it is to be understood that this application is not limited to the particular apparatus described, as there can be multiple possible embodiments which are not expressly illustrated in the present disclosure. It is also to be understood that the terminology used in the description is for the purpose of describing the implementations or versions or embodiments only and is not intended to limit the scope of the present subject matter.
[006] This summary is provided to introduce aspects related to a brushless direct current (BLDC) motor. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the present subject matter.
[007] In one embodiment, a brushless direct current (BLDC) motor includes a power unit, a rotor assembly, a stator, and a controller. The power unit is configured to receive single phase alternating current input from a source. The rotor assembly is having a rotor stack and a Ring type four pole permanent magnet pasted on rotor stack. The permanent magnet is configured to generate a magnetic field. The stator is having three-phase star (Y) winding enclosing the rotor assembly, which is configured to produce magnetic flux. The controller is configured to convert the single phase alternating current input into high frequency pulsating direct current trying to simulate three phase alternating current by using pulse width modulation technique. The width and amplitude of pulses is controlled by controller to control the speed and torque of motor and subsequently control the air flow.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[008] The foregoing detailed description of embodiments is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the disclosure, there is shown in the present document example constructions of the disclosure; however, the disclosure is not limited to the specific apparatus disclosed in the document and the drawings.
[009] The present disclosure is described in detail with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to refer various features of the present subject matter.
[0010] Figure 1A illustrates a sectional view depicting an assembly of a BLDC motor, in accordance with an embodiment of the present subject matter.
[0011] Figure 1B illustrates a top view depicting a BLDC motor, in accordance with an embodiment of the present subject matter.
[0012] Figure 1C illustrates a schematic view depicting a BLDC motor, in accordance with an embodiment of the present subject matter.
[0013] Figure 1D illustrates an exploded view depicting a BLDC motor, in accordance with an embodiment of the present subject matter.
[0014] Figure 2A illustrates a sectional view depicting a sub-assembly of a rotor of a BLDC motor of Figure 1, in accordance with an embodiment of the present subject matter.

[0015] Figure 2B illustrates a top view depicting a rotor, in accordance with an embodiment of the present subject matter.
[0016] Figure 2C illustrates a schematic view depicting a rotor, in accordance with an embodiment of the present subject matter.
[0017] Figure 2D illustrates an exploded view depicting a rotor, in accordance with an embodiment of the present subject matter.
[0018] Figure 3 illustrates a schematic diagram depicting a wound stator, in accordance with an embodiment of the present subject matter.
[0019] Figure 4 illustrates a schematic diagram depicting winding on a stator, in accordance with an embodiment of the present subject matter.
[0020] Figure 5 illustrates a flow diagram depicting an assembly of a BLDC motor in a fan, in accordance with an exemplary embodiment of the present subject matter.
[0021] In the above accompanying drawings, a non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.
[0022] Further, the figures depict various embodiments of the present subject matter for purposes of illustration only. One skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the present subject matter described herein.

DETAILED DESCRIPTION
[0023] Some embodiments of this disclosure, illustrating all its features, will now be discussed in detail. The words "comprising," "having," "containing," and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. It must also be noted that as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Although, a brushless direct current (BLDC) motor, similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, the exemplary, a brushless direct current (BLDC) motor is now described.
[0024] Various modifications to the embodiment will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. For example, although the present disclosure will be described in the context of a brushless direct current (BLDC) motor, one of ordinary skill in the art will readily recognize a brushless direct current (BLDC) motor. Thus, the present disclosure is not intended to be limited to the embodiments illustrated but is to be accorded the widest scope consistent with the principles and features described herein.
[0025] In one embodiment, a brushless direct current (BLDC) motor includes a power unit, a rotor assembly, a stator, and a controller. The power unit is configured to receive single phase alternating current input from a source. The rotor assembly is having a rotor stack and a ring type four pole permanent magnet pasted on rotor stack. The permanent magnet is configured to generate a magnetic field. The stator is having three-phase

star (Y) winding enclosing the rotor assembly, which is configured to produce magnetic flux. The controller is configured to convert the single phase alternating current input into high frequency pulsating direct current trying to simulate three phase alternating current by using pulse width modulation technique. The width and amplitude of pulses is controlled by controller to control the speed and torque of motor and subsequently control the air flow.
[0026] The width and amplitude of pulses is controlled by controller to control the speed and torque of motor and subsequently control the air flow.
[0027] In another implementation, the permanent magnets are neodymium (NdFeB) magnets.
[0028] In another implementation, the modulation technique includes a pulse width modulation (PWM) technique.
[0029] In another implementation, the controller is configured to maximize the air flow based on a predefined speed.
[0030] In another implementation, the four pole ring type permanent magnet on the rotor stack is having a plurality of poles.
[0031] In another implementation, the PWM technique is used to control the rotation of the BLDC motor based on a predefined cycle or pulse width.
[0032] In another implementation, the three-phase winding is having at least 435 number of turns per coil.
[0033] In another implementation, the BLDC motor includes a plurality of stator poles surrounded by the permanent magnets. The stator poles are 4.

[0034] In another implementation, the coil turning inside the generated magnetic field induces a back electromotive force (emf). The back emf at 1300-1400 revolutions per minute (rpm) is 102 to 112 volts.
[0035] Figure 1A illustrates a sectional view depicting an assembly of a BLDC motor (100), in accordance with an embodiment of the present subject matter. Figure 1B illustrates a top view depicting a BLDC motor a, in accordance with an embodiment of the present subject matter. Figure 1C illustrates a schematic view depicting a BLDC motor a, in accordance with an embodiment of the present subject matter. Figure 1D illustrates an exploded view depicting a BLDC motor, in accordance with an embodiment of the present subject matter.
[0036] A BLDC motor (100) includes a power unit (not shown in a figure), a rotor assembly (102), a stator (shown in Figure 2), and a controller (not shown in a figure).
[0037] In an embodiment, the BLDC motor (100) includes a rotor assembly (102) which is fixed inside a shell. The BLDC motor (100) further includes a mounting shaft (104), a front-end shell (106), back-end shell (108), a shaft (110) which helps in rotating the motor (100), and a shell body top cover (112) to cover the rotor assembly (102) and the stator. In another embodiment, the shell is made of aluminum.
[0038] The power unit is configured to receive single phase alternating current input from a source. This single phase alternating current input into high frequency pulsating direct current trying to simulate three phase alternating current by using pulse width modulation technique. Further this high frequency pulsating direct current is fed to three phase star (Y) connected winding and results in producing revolving magnetic field in

stator. Rotor has its own magnetic field due to four pole magnet pasted on to it. Magnetic poles of the stator attracts the closest pole of permanent magnet of the opposite polarity. The rotor (102) moves if the current shifts to an adjacent winding. Mutual interaction of two magnetic fields causing the production of torque in rotor.
[0039] The rotor assembly (102) is having a rotor stack and a ring type four pole permanent magnet (shown in Figure 2) pasted on the rotor stack, the permanent magnet is configured to generate a magnetic field. In an embodiment, the permanent magnet include, but is not limited to, neodymium (NdFeB) magnets. In an embodiment, the ring type magnet pasted on rotor stack is having a plurality of poles. In an embodiment, the rotor assembly (102) includes the permanent magnet and it rotates inside an armature. The rotor assembly (102) helps to reduce the loss of heat. In the BLDC motor (100), the rotor is located inside the stator, thereby producing more torque.
[0040] The stator is having three-phase winding enclosing the rotor assembly (102). The stator is further configured to produce magnetic flux. In an embodiment, the three-phase winding is having at least 435 number of turns per coil. In one embodiment, the coil turning inside the generated magnetic field induces a back electromotive force (emf). The back emf at 1300-1400 revolutions per minute (rpm) is 102 to 112 volts.
[0041] In an embodiment, the BLDC motor (100) a plurality of stator poles surrounded by the permanent magnet. In an embodiment, the stator poles are 4.
[0042] The controller is configured to convert the single phase alternating current input into high frequency pulsating direct current trying to simulate

three phase alternating current by using pulse width modulation technique. This high frequency pulsating direct current is further fed to the three phase star connected stator winding. This induces revolving magnetic field in the stator. The mutual interaction of both fields (Stator magnetic field & Rotor magnetic field) produces torque in the rotor. The width and amplitude of pulses is controlled by controller to control the speed and torque of motor and control the air flow. In an embodiment, the controller is configured to maximize the air flow based on a predefined speed. The predefined speed is set by a user by using a fan regulator. In one embodiment, the modulation technique includes, but is not limited to, a pulse width modulation (PWM) technique. The PWM technique is used to control the rotation of the BLDC motor (100) based on a predefined cycle or pulse width.
[0043] Figure 2A illustrates a sectional view depicting a sub-assembly of a rotor (102) of a BLDC motor (100) of Figure 1, in accordance with an embodiment of the present subject matter. Figure 2B illustrates a top view depicting a rotor (102), in accordance with an embodiment of the present subject matter. Figure 2C illustrates a schematic view depicting a rotor (102), in accordance with an embodiment of the present subject matter. Figure 2D illustrates an exploded view depicting a rotor (102), in accordance with an embodiment of the present subject matter.
[0044] The rotor assembly (102) is having a rotor stack and a ring type four pole permanent magnets (206) pasted on the rotor stack, where the permanent magnet is configured to generate a magnetic field. In an embodiment, the permanent magnets include, but are not limited to, neodymium (NdFeB) magnets. In an embodiment, the rotor magnetic ring is having a plurality of poles, and the permanent magnet is pasted on the rotor stack. In an embodiment, the rotor assembly (102) includes the permanent magnet and it rotates inside an armature. The rotor assembly

(102) helps to reduce the loss of heat. In the BLDC motor (100), the rotor is located inside the stator (204), thereby producing more torque. The bearings (208) are used to support the shaft (110) with the rotor assembly (102).
[0045] The stator (204) is having three-phase winding enclosing the rotor assembly (102). The stator (204) is further configured to produce magnetic flux. In an embodiment, the three-phase winding is having at least 435 number of turns per coil. In one embodiment, the coil turning inside the generated magnetic field induces a back electromotive force (emf). The back emf at 1300-1400 revolutions per minute (rpm) is 102 to 112 volts.
[0046] Figure 3 illustrates schematic diagram depicting a wound stator (300), in accordance with an embodiment of the present subject matter.
[0047] In an embodiment, the stator (204) is wound with copper wires. The stator (204) is having three-phase winding enclosing the rotor assembly (102). Here, the three-phase winding is having at least 435 number of turns per coil. In one embodiment, the coil turning inside the generated magnetic field induces a back electromotive force (emf). The back emf at 1300-1400 revolutions per minute (rpm) is 102 to 112 volts. In one embodiment, the coil is made of copper material.
[0048] Figure 4 illustrates schematic diagram (400) depicting winding on a stator, in accordance with an embodiment of the present subject matter.
[0049] In Figure 4, the stator (204) is wound with a super enameled copper winding wire and have three-phase star (Y) winding. The wire includes three-phases at start and end of the wire. For example, the three-phase at the start end includes r-phase start (denoted as a red color), y-phase start (denoted as a yellow color), and b-phase start (denoted as a blue color). These 3 phase windings are connected from a connector port (not shown in

a figure) of the controller. Further, at the end of the wire the three-phase includes r-phase end (denoted as a red color), y-phase end (denoted as a yellow color), and b-phase end (denoted as a blue color) are shorted together to form the star (Y) connection. These 3 phase windings are inserted in the stator (204).
[0050] In an exemplary embodiment, the BLDC motor (100) is assembled with a fan. In an embodiment, the fan can be a wall mounted fan, a ceiling fan, or pedestal fan. Suppose, the size of the fan is 18 inches. The winding details for the 18 inches fan are as follows:

S.No. Parameter Value
1 Input Voltage 230V AC
2 Input power 65W
3 RPM 1400
4 Sweep 450mm
5 Slots 6
6 Poles 4
7 Wire size 33SWG
8 No. of turns per coil 435
9 No. of coils per phase 2
10 Resistance (R-Y) 86.5 (±5%) Ω
11 Inductance (R-Y) 310 (±5%) mH
12 Back emf @1400rpm 111 (±2%) V
Similarly, if the size of the fan is 24 inches, the winding details for the fan are as follows:

S.No. Parameter Value
1 Input Voltage 230V AC

2 Input power 85W
3 RPM 1300
4 Sweep 600mm
5 Slots 6
6 Poles 4
7 Wire size 33SWG
8 No. of turns per coil 435
9 No. of coils per phase 2
10 Resistance (R-Y) 86.5 (±5%) Ω
11 Inductance (R-Y) 310 (±5%) mH
12 Back emf @1300rpm 102.5 (±2%) V
[0051] Figure 5 illustrates a flow diagram (500) depicting an assembly of a BLDC motor (100) in a fan, in accordance with an exemplary embodiment of the present subject matter.
[0052] In an embodiment, the BLDC motor (100) consists of a stator (204) and a rotor assembly (102). The stator assembly includes a wound stator (502). In the wound stator (502), the stator windings are connected to form three phase star (Y) connection. The stator assembly includes a winding parameter test (504) for measuring winding resistance, and a bottom end shield fixing (506). The rotor assembly (102) includes a rotor stack press (508), which includes multiple laminations where each lamination is circular. The ring type four pole magnets are then glued (as shown at a block 510), and then bearing press (512), and form a rotor. The assemblies of the stator and rotor provide the BLDC motor (100). The BLDC motor (100) further includes top end shield fixing (514), printed circuit board (PCB) mounting (516), perform high voltage testing (518) to verify the insulation of components, cowl assembling (520), bracket fixing (522), and then final assembly (524) of the BLDC motor (100). Further, it performs high voltage

and megger testing (526), speed test (528), energy parameter testing (530),
air delivery test (532), and noise level test (534).
[0053] In an embodiment, the BLDC motor (100) is configured to reduce the
power consumption of the fan.
[0054] In an embodiment, the BLDC motor (100) is designed for 230V AC
input which will then be converted to high frequency pulsating direct
current by the controller (through PWM technique). The rotor (102) consists
of permanent magnet (NdFeB) which provide better torque. A blade profile
is designed to maximize the air delivery for a given speed.
[0055] In an embodiment, the BLDC motor (100) is used, where the motor
works on high frequency pulsating direct current trying to simulate three
phase alternating current instead of alternating current in case of induction
fans. The single phase alternating current input supply is converted to high
frequency pulsating direct current with the help of PWM and modified
according to the feedback of the motor (100) by the controller.
[0056] In an embodiment, the BLDC motor (100) makes the fan energy
efficient and gives a saving of up to 50%.
[0057] In an embodiment, the BLDC motor (100) produces very less noise
as compared to other fans.
[0058] In an embodiment, weight of the BLDC motor (100) is less than
ordinary fans which gives improves handling of fans and transportation.
[0059] In an embodiment, the size of the BLDC motor (100) is less and
compact which gives better scope for aesthetics.
[0060] Although the description provides implementations of a BLDC
motor, it is to be understood that the above descriptions are not necessarily
limited to the specific features or methods of apparatus. Rather, the specific
features and methods are disclosed as examples of implementations for a
BLDC motor.

We Claim:
1. A brushless direct current (BLDC) motor (100), comprising:
a power unit configured to receive alternating current input from a
source;
a rotor assembly (102) having a rotor stack and a four pole permanent magnet pasted on the rotor stack, the permanent magnet is configured to generate a magnetic field;
a stator (204) having three-phase star (Y) winding enclosing the rotor assembly (102), the stator (204) configured to produce magnetic flux; and
a controller configured to convert single phase alternating current input into high frequency pulsating direct current trying to simulate three phase alternating current by using pulse width modulation technique. The width and amplitude of pulses is controlled by controller to control the speed and torque of motor and subsequently control the air flow.
2. The BLDC motor (100) as claimed claim 1, wherein the permanent magnets are neodymium (NdFeB) magnets.
3. The BLDC motor (100) as claimed claim 1, wherein the modulation technique includes a pulse width modulation (PWM) technique.
4. The BLDC motor (100) as claimed in claim 1, wherein the controller is configured to maximize the air flow based on a predefined speed.
5. The BLDC motor (100) as claimed in claim 1, wherein the magnet pasted on the rotor stack is having a plurality of poles.

6. The BLDC motor (100) as claimed in claim 1, wherein the PWM
technique is used to control the rotation of the BLDC motor (100) based on
a predefined cycle or pulse width.
7. The BLDC motor (100) as claimed in claim 1, wherein the three-phase winding is having at least 435 number of turns per coil.
8. The BLDC motor (100) as claimed in claim 1, comprising: a plurality of stator poles surrounded by the permanent magnet.
9. The BLDC motor (100) as claimed in claim 9, wherein the stator poles are 4.
10. The BLDC motor (100) as claimed in claim 7, wherein the coil turning inside the generated magnetic field induces a back electromotive force (emf).
11. The BLDC motor (100) as claimed in claim 10, wherein the back emf at 1300-1400 revolutions per minute (rpm) is 102 to 112 volts.