The Secret Behind Declining Home Appliance Energy Consumption — The Rise of BLDC Technology

Debates over nuclear power continue to divide public opinion, but one fact is undeniable: saving electricity has become a major social priority. In the field of lighting, the shift from incandescent and fluorescent lamps to LEDs has already achieved significant energy savings. Yet the most effective path to energy conservation lies in motor efficiency, and this is especially evident in household appliances.

From Induction Motors to Brushless DC Motors

In the household sector, air conditioners and refrigerators account for a large share of total electricity consumption. Before the 1990s, appliances such as air conditioners, refrigerators, washing machines, and vacuum cleaners almost exclusively relied on induction motors.

After the 1990s, however, a technological revolution began. Vector control technology for brushless DC (BLDC) motors was rapidly introduced, first in air conditioners, refrigerators, and drum-type washing machines.

Today, the term “inverter air conditioner” is no longer new. But it is worth noting that inverter air conditioners of the 1980s still used induction motors, while those developed after the 1990s adopted BLDC motors, fundamentally transforming variable-frequency control technology.

Efficiency Gains You Can See

Visit a home appliance showroom and you may find refrigerators of the same size displaying annual energy consumption figures that differ by more than a factor of two. While insulation and compressor design play a role, the biggest difference lies in the efficiency of the compressor motor.

Some manufacturers even advertise that their products consume “only one-third of the electricity” of conventional models—a claim made possible by replacing traditional induction motors with BLDC motors.

For now, BLDC motors are still primarily used in high-end appliances such as air conditioners, refrigerators, and drum-type washing machines because they remain more expensive than induction motors.

However, as energy-saving awareness grows and motor costs continue to fall, it is only a matter of time before fans, juicers, washing machines, vacuum cleaners, and other household products widely adopt BLDC motors.

What Is a BLDC Motor?

A Brushless Direct Current (BLDC) motor is essentially a DC motor without the carbon brushes used in older brushed designs. Eliminating brushes reduces wear, improves efficiency, and extends lifespan.

Early BLDC motors were typically driven by square-wave signals. To reduce vibration, sine-wave drives were later introduced. For position detection, sensorless control without Hall elements became common.

Today, vector control technology is widely applied, maximizing the conversion of input current into rotational torque for even higher efficiency.

Another Name You Might Hear: PMSM

BLDC motors are sometimes referred to as PMSM (Permanent Magnet Synchronous Motor), reflecting their use of permanent magnets to achieve synchronous rotation.

The Development of Vector Control Technology for Brushless DC Motors

In the past, automobiles utilized numerous motors. With the advent of the EV era, motors are replacing internal combustion engines as a critical foundational technology. The power efficiency of motors directly influences EV energy consumption and driving range, while high starting torque and vibration-free motor operation have become key competitive differentiators in EV performance.

A notable example is the Tokyo Metro Ginza Line, where trains equipped with Permanent Magnet Synchronous Motors (PMSM) were introduced in September 2007. Subsequent operational data collection revealed significant improvements compared to traditional induction motors:

• Reduction in power consumption: 6.8%
• Noise improvement (at 65 km/h): 86.7 dB (induction motor) → 85.0 dB (PMSM)

These results demonstrate clear benefits, and the future adoption of brushless DC motors in rail transportation systems holds great promise.

In the industrial sector, electric motors account for a substantial 69.0% of total electricity consumption. According to 2008 data from Japan's Ministry of Economy, Trade and Industry (METI), the domestic shipment statistics for three-phase and single-phase induction motors were as follows:

• Unit volume: 11.28 million (92% of total)
• Power capacity: 22,767 MW (92% of total)

Three-phase induction motors alone consume approximately 75% of the electricity used in Japan's industrial sector, representing about 55% of the country's total power consumption. These motors are widely used in pumps, fans, compressors, and various other applications.

While it is not yet feasible to definitively claim that "replacing induction motors with brushless DC motors will save XX% of energy" due to technical challenges and equipment costs, the global focus on environmental and energy issues suggests that transitioning to high-efficiency motors will be a mid- to long-term trend.

Brushless DC motor vector control technology has already been adopted in industrial automation robotics, home appliances such as air conditioners, refrigerators, and drum washing machines, and as power sources for EVs. In the future, this technology is expected to expand across all motor-driven applications—at least, that is the author's current perspective.