ROHM Semiconductor introduces ‘Made for India' power saving BLDC Motor solution


  • Introducing Brushless DC (BLDC) motor solution for Energy Efficient Ceiling Fans & Room AC Outdoor Unit Fans
  • Use of BLDC motors can reduce power consumption of home appliances and industrial equipment by 50%
  • Designed in India, designed for India

Bangalore, September 20th 2016: ROHM Semiconductor India Pvt. Ltd. (RSI), a ROHM group company has today announced the introduction of its path breaking Solutions for driving BLDC motors in India. These solutions, compared to the less expensive AC Induction motor, are easy to control and around 50% more efficient, thereby reducing power consumption in Home Appliances and Industrial equipment. The solutions are designed with features to reduce the design time and hence enable a faster time to market. These drivers along with the easily customizable reference designs will propel local design, which is the key to manufacturing locally. This high efficiency in BLDC motors is achieved by precise electronic switching of the currents to the windings.

RSI developed reference designs for 2 popular BLDC application, i.e., 30W class ceiling fan, and a 70W class Room Air Conditioner (RAC) Out Door Unit (ODU) condenser fan using our highly integrated "Smart IPM" (Intelligent Power Module) series BM620XFS. This "Smart IPM" brings ROHM's market-proven BLDC controller, packaged along with gate drivers, and the 600V PrestoMOS™(1 During normal operation a voltage of around 340V DC (240AC = 240 x √2 = 340VDC) is good enough, and considering around 50% margin many of the competitors' line-up has an absolute maximum of 500V. ROHM analyzed some of the field failure in the Indian market, and designed the smart IPM with 600V MOSFET, which can withstand the harshest of the voltage fluctuations seen every day.

ROHM's BLDC Motor solution for India BM620xFS Packages

Market background

India's electricity consumption has increased exponentially due to rise in the usage of high-power household electrical appliances like air conditioners. Rural electrification drive initiated by the Government has also added to the increasing demand for electrical supply. However, there is a significant gap in the demand vs power generation & supply and therefore, conservation using energy efficient appliances is the need of the hour. The Government through its various initiatives, is starting to focus on energy conservation by propagating use of energy efficient BLDC ceiling fans, CFL & LED bulbs as opposed to conventional fans using AC induction motor and filament bulbs.

In 2015, India manufactured around 40 Million ceiling fans, with around 10% growth year-on-year. If every single ceiling fan manufactured from here on is made into an energy efficient BLDC ceiling fan, rough calculation indicates that, by 2025, the country can reduce peak-power capacity addition by around 10 GW, which is equivalent to saving around 5 midsized power plants.

The next most manufactured electrical appliance is the ceiling fan, conventionally using AC induction motor. On an average every Indian household has around 2~3 ceilingi fans. After tasting success with the energy efficient bulbs, the government is starting to focus on ceiling fans. The government has started programs to propagate energy efficient ceiling fans into every household. There are a lot of reasons why this is going to be a success. India manufactured around 40 Million ceiling fans in 2015, with around 10% growth year-on-year. If every single ceiling fan manufactured from now is made into an energy efficient BLDC ceiling fan, rough calculation indicates that, by 2025, the country can reduce peak-power capacity addition by around 10 GW, which is equivalent to saving around 5 midsized power plants. BLDC ceiling fans, besides being highly efficient can also be designed for a power factor of 0.9 or above, which reduces the burden on the power-grid further.ii

In a household powered by an UPS, a BLDC ceiling fan can be used 4 times longer duration than an AC Induction ceiling fan at full speed, and approximately 10 times longer at low speedsiii. This will be highly useful in remote villages where power outages are common. Moreover, BLDC ceiling fan can be easily designed for directly connecting to the solar panel (48V DC) and this will remove the costly and low efficient DC-AC inverter stage. Thus the ceiling fan becomes a hybrid device, working with both the 240AC, and also the 48VDC directly. This is very important for the UDC (Un-interrupted DC)iv, and OGH (Off Grid Home) initiatives by the government of India.

The next target application is RAC (Room Air Conditioners) ODU (Out Door Unit) fan, which consumes around 160W with the AC Induction motor. Similar to the power-savings in ceiling fan, using a BLDC motor will reduce the power consumption by 50%. All RAC sold in India, need to save around 30W of power from the current consumption levels, to achieve the next BEE (Bureau of Energy Efficiency) 5★ ratings. The Indian RAC industry have already exhausted almost all the options with the compressor refrigerants, and now the options available are, (1) changing the compressor motor to BLDC, which is expensive, (2) the other option is to change the ODU condenser motor to BLDC. The later change will ensure a saving of around 80W, and this will help the RAC to be rated at BEE 5★ for the next few yearsv. RSI anticipates that the demand for this solution will grow as the number of ODU units manufactured locally is increasing.

Applications 1

The ultimate aim is "the digital air-conditioner", and as the next step, target to work on the silent Indoor Unit blower fan, which is similar in power consumption to the ceiling fan. A plan to work on the compressor motor power-savings is also on cards.

Applications 2
  1. Reference: World bank data;
  2. Reference: The Overlooked Appliance in Energy Efficiency Discussions, Prayas Group.
  3. According to our calculations
  5. Assuming the rating as of 2016

Ceiling fan – at a glance

Ceiling fan manufacturing started after the Indian independence. JE engineering started manufacturing in Calcutta, and later transferred the factory to Hyderabad owing to labor problems. After some years, JE outsourced the ceiling fan's components to 3rd party suppliers, and later procured the whole ceiling fan. Many small manufacturing units mushroomed in Hyderabad as JE slowly lost ground and later disappeared. This is the reason why Hyderabad continues to be the hub of ceiling fan manufacturing.

Almost 85% of the current ceiling fan Industry is made up of 8 major brands along with some hundred other brands. The remaining market is shared by thousands of small scale manufacturers. An average branded ceiling fan costs around INR 1500, while a non-branded one costs around INR 650. These pricing has created a kind of benchmark which the BLDC ceiling fans should compete. The government is trying to bring this entry hurdle down by giving various sops to BLDC ceiling fan

Features of BLDC motor solution

The ceiling fan solution is made up of 3 major blocks. The (1) Power Factor Controller (PFC), (2) BLDC controller and (3) The control block. The Power Factor Control block, besides converting the AC source into DC, also corrects the Power Factor (PF). This block also provides an auxiliary power supply to the microcontroller. The specification of this block is shown in Table XX. It uses the highly integrated ROHM AC/DC converter IC, BD769xJ.

The BLDC controller block drives the BLDC motor; this block comprises just the ROHM's "Smart IPM" (Intelligent Power Module), BM6208FS. The supply voltage for this block is from the PFC block, and the control signals are from the microcontroller. The "Smart IPM", has the motor control, gate driver, and the 600V PrestoMOSTM all in the same package, thus saving space. High voltage also equates to high efficiency as the losses in the power stage is reduced due to the lower operating currents.

The block diagram for the ROHM ceiling fan solution is shown below.


The key specification for the ceiling fan is shown below

1 Supply voltage [nominal] 230 Volt
2 Voltage range [Input] 0.17-0.21 Amp
3 Rated Current [Input] 0.17-0.21 Amp
4 Input Power 32 – 40 Watts
5 Standby power 0.5 Watt
6 Power factor >0.91  
7 Speed (max) 330 – 360 RPM
8 Speed regulation & remote Steps 50% to Full speed RPM
Step.1: 204 RPM
Step.2: 240 RPM
Step.3: 298 RPM
Step.4: 327 RPM
Step.5: 350 RPM
9 Starting Smooth/Jerk less  
10 On fly behavior should pick up smoothly and accelerate  
11 Low voltage operation Fan should work at full speed @ 90V  
12 Default speed Last used speed by the user  
13 Remote function Speed selectable, Modes (optional)  
14 Timer function 1, 2, 4, 8 hour timer  
Protection features
15 Locked rotor protection Fan stops after 4 seconds  
16 Over current protection Fan stops if current exceeds 0.6A  
17 Over voltage protection Fan stops if voltage exceeds 265V  

Similarly, ROHM has released BM6209FC for the RAC ODU motor application. This Smart IPM can drive loads of 2.5A, which is suitable for ODU, Air coolers, Air curtain and other 70W class application.

vi. Reference: The Overlooked Appliance in Energy Efficiency Discussions, Prayas Group.

BM620X series can also be used in the following application

  • Ceiling Fan
  • Air Conditioner
  • Air Cooler
  • Air Purifiers


1) PrestoMOS:
‘Presto' is an Italian musical term meaning ‘very fast'. ROHM PrestoMOSTM is characterized by lower ON resistance and faster reverse recovery time of the internal diode compared with conventional MOSFET products, making it ideal for integrated power supply inverters.