Claims:WE CLAIM :

1. A power system which is capable of simultaneous motoring and generating operation with a BLDC motor comprising :

a. a main power source,
b. an electrical load such as a ceiling fan operable with a BLDC motor and in its spinning state is capable of generating electricity based on unique winding pattern which is winding distribution with uniform phase shift of 120 degrees for motor and generator coils without any overlapping,
c. a first and second batteries,
d. a convertor switching means is connected to the fan and to both batteries and configured to operate in a first, second and third mode,
e. a controller adapted to control the changeover of convertor switching modes based on the signals of power availability in main power source and two batteries,

wherein the first mode the fan input is connected to output external main power supply and BLDC generated power of the spinning fan is connected to input of first battery and input of second battery such as, to first charge the first battery upto a desired charge level and subsequently initiate charge of the second battery upto a desired charge level,

wherein the second mode, the fan input is connected to output of charged first battery and BLDC generated power of the spinning fan is connected to input of second battery to charge the second battery upto desired charge level,

wherein the third mode, the fan input is connected to output of charged second battery and BLDC generated power of the spinning fan is connected to input of first battery to charge the first battery upto desired charge level, and

wherein the winding distribution for motor with uniform phase shift of 120 degrees is arranged such that motoring and generating operation from the motor coils is done through different stator slots with half of total stator slots contributing for motoring operation and other half of stator slots contributing for generating operation,

the said arrangement characterised in that motion of the fan itself is continuously harnessed to generate electricity irrespective of source to which it is connected amongst the three available power sources i.e., main external supply, the first battery or the second battery, such that the first mode is operationally switched when main power source is available, the second mode is operationally switched when main power source is interrupted and a first battery is in charged state and the third mode is operationally switched when main power source is interrupted, first battery is not in charged state and second battery is in charged state.
, Description:FIELD OF INVENTION :

The invention relates to a BLDC motor driven ceiling fan. The fan includes a motor, a rotatable hub, and a plurality of blades. The motor is typically coupled with the hub by a hollow drive shaft such that the drive system of the fan is gearless. Also the motor is a permanent magnet brushless DC motor, which comprises of permanent magnet motor.

PRIOR ART :

Different evolution of motors technology is arrived for ceiling fan application. It is discussed below as generation.

In conventional ceiling fan application, single phase squirrel cage induction motor is used. The main drawbacks in induction motor for ceiling fan application follows; larger dimension requires to achieve the rated load, power consumption of this motor is very high(~60-80W) and noise produced by induction motor is higher due to ageing factor.

OBJECT OF THE INVENTION :

To overcome above mentioned problem, Brushless DC Motor (BLDC) concept was introduced. Motor size will be in compact size, because of permanent magnet in the rotor side; higher torque can be achieved easily with smaller constrained dimension with less energy consumption (~30-50W).

Proposed novel concept envisaged in the invention

In this proposed motor topology can able to perform motoring and generating operation at same instance of time. It can be achieved by modifying the winding pattern of proposed BLDC machine. This concept is adopted for ceiling fan application to perform dual operation. The generated electrical energy from the proposed machine can be stored back to the battery and can be used back again during power demand time.

Novel features of the invention achieved in the invention

1. Proposed motor can deliver motor and generator operation at same instance of time.
2. Uninterrupted operation of ceiling fan during power supply on and off condition.
3. Proposed concept can also be easily adoptable with existing BLDC motor with lesser energy consumption.

BRIEF DESCRIPTION OF DRAWINGS :

Figure 1:Winding layout of proposed BLDC machine with working flow diagram
PART NO. PART NAMES
A1 Motor circuit
A2 Motor terminals
A3 Motor Controller
A4 Switched Mode power supply
A5 AC Power supply (230V, 50Hz)
A6 Input supply
A7 Battery 1:48 W
A8 Battery 2:48 W
A9 BMS
A10 Generator Circuit
A11 Generator terminals
A12 Converter (AC-DC) & Voltage doubler circuit

Figure 2: Electrical power consumption comparison for one day
PART NO. PART NAMES
B1 Power consumption in 24 hours (W)
B2 Induction fan (70 W)
B3 BLDC fan (44 W)
B4 BLDC fan (35 W)
B5 Proposed fan (44 W)

V. DETAILED DESCRIPTION :

In proposed BLDC motor concept can be independently adopted for (48, 36, 24, and 12) stator slot. Rotor is developed as an outer rotor concept for ceiling fan application. The working flow of proposed BLDC motor is shown in the block diagram in figure 1. The main components involved in this concept are BLDC motor with modified winding layout, AC power source, switched mode power supply(SMPS), BLDC controller, converter circuit, Battery Management System (BMS) and two lithium ion batteries. (refer Block diagram)

This proposed winding topology of BLDC motor is focus towards the generation of electricity from BLDC during motoring mode itself. It can also be used as a free energy concept for shorter duration of time. In order to make this energy conversion effectively, test setup needs to be installed like shown in the block diagram. Initially single phase AC supply is given to the switched mode power supply, where 230V, 50Hz is converted to 24 V DC supply through controller. The converted voltage is given to the BMS where it regulate the DC voltage and also it act as a decision maker. Here two batteries are used for motoring and generating modes, motor input is given from one battery means and another battery is used to charge the generating electric power from the BLDC motor. Input power for the motor controller is receives from the battery source, then it converts DC source into PWM (Pulse Width Modulation) pulses to energise motor terminal coils. As per the faradays law of electromagnetism, “a current carrying conductor placed in a magnetic field it experiences a force or torque’’. Based on this principle, coils are energised for the three set of phases R (M-ph1), Y (M-ph2), B (M-ph3). The detailed winding flow is given in the table 1 for reference. The winding pattern shown in the block diagram is the proposed winding pattern with equal stator slots contributes for motoring operation; another six stator slots are winded O (G-ph1), G (Gph2), P (G-ph3) for tapping the generated electrical energy. The electrical output from the O, G, P terminals are in the form of sinusoidal AC waveform. The resultant AC output from the proposed motor is about 6 V at 354 rpm This AC is converted into DC for charging the battery. It can be performed using rectifier or converter circuits, 6 volt of AC is now converter into 15.6 V DC using diode bridge rectifier circuit. In order to charge the 24V battery, it requires minimum of 26V. So, voltage doubler circuit is incorporated with diodes and capacitor to improve the rectified voltage. At the end of voltage doubler circuit, resultant voltage of 26-27 V is achieved with 1.833 A. This energy is sufficient to charge the battery placed in the BMS.

This charging and discharging of battery is performed continuously for running the ceiling fan application without any dependency of input power supply.

Work flow and winding pattern:

The different modes of operation to attain the free energy concept is given below

Mode 1: [AC supply used as a primary source for motor]

Input supply is available to charge the battery 1 and it drives the proposed motor, the resultant generated electrical output is stored in the battery 2.

Mode 2: [Battery 1 used as a source for motor]

Once battery 1 is fully charged to 100 % means, input AC power supply will be disconnected. Electrical power requires to drive the electric motor is given from the battery 1.similarly power generated from the proposed motor is given to the battery 2. This process will continue till it battery 1 reaches to 10%.

Mode 3: [Battery 2 used as a source for motor]
In mode 3 operations, once battery 1 reaches 10% level. In this case, battery 2 will be used as a primary source for proposed motor, this switching between batteries can be achieved by battery management system. This mode 3 and 2 will be repeated till both batteries reaching 10%. In case it reaches this state means, it follows mode 1 operation.

Winding pattern:
The unique winding layout of proposed model for motoring and generating is shown in the table 1.
Table 1:
Motor winding layout:

Motor Phase coils Go Return Go Return Gorges (Phase shift)
R (M-ph1) 1 2 4 5
Y (M-ph2) 2 3 5 6
B (M-ph3) 3 4 6 7

Generator winding layout:

Generator Phase coils Go Return Go Return Gorges (Phase shift)
O (G-ph1) 7 8 10 11
G (G-ph2) 8 9 11 12
P (G-ph3) 9 10 12 1

Here, 12 stator slots are uniformly and independently distributed for motor and generator without any overlapping. In order to perform motoring operation, six consequent stator slots are winded (R, Y & B phase) respectively with 120 deg phase shift. Similarly next six consequent stator slots are winded with 120 deg phase shift for generating operation (O, G & P phase) respectively. This winding topology can able to perform its dual operation with risk free from overheating, short circuiting condition between motor and generator coils. It is achieved because of slots allocation; here slots are individually dedicated for motor and generator without any overlapping between them. In table 2 shows the design specification of proposed motor with its power rating.

BATTERY BACKUP CALCULATION

In this section highlights the specification details of motor and battery for proposed ceiling fan application. The time and current required to charge and discharge the battery are calculated based on analytical equation which are mentioned below. The motor specification and charging details are mentioned clearly in the table 2 and 3
Table 2: Motor and battery specification

Parameters Value
Motor Nominal load power 44 W
Motor load current 1.833 A
Motor input voltage 24 V
Battery capacity 12 V, 2 Ah & 12V, 2 Ah connected as series

Table 3: Battery charging and discharging level

Discharge level in percentage Discharging time (Hours) Discharge time (Mins) Charge level in percentage charging time (Hours) Discharge time
(Mins)
100 %
1.09 65.4 100 %
1.41 85.09
90% 0.981 58.86 90% 1.28 76.58
80 % 0.872 52.32 80 % 1.13 68.07
70% 0.763 45.78 70% 0.99 59.56
60% 0.654 39.24 60% 0.85 51.06
50% 0.545 32.7 50% 0.71 42.55
40% 0.436 26.16 40% 0.57 34.04
30% 0.327 19.62 30% 0.43 25.53
20% 0.218 13.08 20% 0.28 17.02
10% 0.109 6.54 10% 0.14 8.51

Formula:
Discharge time (Hours)=(Nominal battery current rating (Ah))/(Load current (A)) =2/1.833 = 1.09 hours.
charge time (Hours)=(Nominal battery current rating Ah + (30% losses))/(input current (A) )
=(2+0.6)/1.833
=1.41 hours

Back EMF constant= Generated voltage / Angular momentum
=0.168*1.414 =0.262

Based on the workflow and analytical calculation, input power dependency is analyzed for 24 hours, the same calculation is going to be repeated for throughout the year. The sample is mentioned below in the table 4 for reference.

Table 4: Electrical power dependancy

Modes of operation Charging Time (hrs) Battery condition Power consumption
Battery 1 Battery 2
Input supply 100 10 (NC) 1.15 OFF 44 watts
Battery 1 10 70 2.15 ON -
Battery 2 50 10 2.55 ON
Battery 1 10 30 3.21 ON
Battery 2 10 10 3.35 ON
Input supply 100 10 (NC) 4.50 OFF 44 watts
Battery 1 10 70 5.50 ON -
Battery 2 50 10 6.30 ON
Battery 1 10 30 6.56 ON
Battery 2 10 10 7.10 ON
Input supply 100 10 (NC) 8.25 OFF 44 watts
Battery 1 10 70 9.25 ON -
Battery 2 50 10 10.05 ON
Battery 1 10 30 10.31 ON
Battery 2 10 10 10.45 ON
Input supply 100 10 (NC) 12.00 OFF 44 watts
Battery 1 10 70 13.00 ON -
Battery 2 50 10 13.40 ON
Battery 1 10 30 14.06 ON
Battery 2 10 10 14.32 ON
Input supply 100 10 (NC) 15.47 OFF 44 watts
Battery 1 10 70 16.47 ON -
Battery 2 50 10 17.27 ON
Battery 1 10 30 17.53 ON
Battery 2 10 10 18.08 ON
Input supply 100 10 (NC) 19.23 OFF 44 watts
Battery 1 10 70 20.23 ON -
Battery 2 50 10 21.03 ON
Battery 1 10 30 21.29 ON
Battery 2 10 10 21.43 ON
Input supply 100 10 (NC) 22.58 OFF 44 watts
Battery 1 10 70 23.58 ON -
Battery 2 50 10 24.38 ON
Battery 1 10 30 25.18 ON
Battery 2 10 10 25.32 ON

*NC-No charging state

Table 5: Energy consumption comparison:

Type of fan motor Power consumption (W)
24 hours 31 days 6 months
(182 days) one year
(365 days)
Induction fan (70 W) 1680 52080 305760 613200
BLDC fan (44 W) 1056 32736 192192 385440
BLDC fan (35 W) 840 26040 152880 306600
Proposed fan (44 W) 308 9548 56056 112420

In conclusion it can be easily stated that invention has commercial utility

This proposed concept can effectively save 63% of energy, comparable with 35 W BLDC fan variant. The dependency of main electrical input supply (230V, 50Hz) for one day is reduced from 24 hours to 8.05 hours. The effectiveness of the concept is validated by electromagnetic simulation and also using prototype testing.

The disclosed description of certain examples of the invention should not be used to limit the scope of the present invention. Other examples, features, aspects, embodiments and advantages of the invention will become apparent to those skilled in the art from the disclosed description, when is by way of illustration, one of the best modes contemplated for carrying out the invention. As will be realised, the invention is capable of other different and obvious aspects, all without deporting from the invention. Accordingly the drawings and description should be regarded as illustrative in nature and not restrictive. Accordingly the scope of the present invention should be considered in terms of the following claims and as understood not to be limited to the structure and operation shown and described in the specification and drawings.