The role of power semiconductors in enhancing home appliance efficiency - Embedded.com

The role of power semiconductors in enhancing home appliance efficiency

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As attention increasingly focuses on climate change, energy efficiency in appliances will be a key way to curb energy consumption and thus lower greenhouse gases.

Human’s impact on Earth can’t be denied, and there are global efforts under way to strike a better balance between the amenities and luxuries we enjoy and reducing the environmental impact. One such movement is to improve home-appliance efficiencies through standards such as Energy Star efficiencies. The United States has historically been behind in enforcing new efficiency standards. Right now, for example, if you look at the HVAC compressor marketplace prior to these regulations going into effect, the U.S. was at only 5% of the market being inverterized for the HVAC compressor. On the other end of the spectrum, China is almost 100% inverterized already, and Europe is about 65% because they had regulations that made that happen earlier.

The good news is the U.S. has realized the need for better efficiencies, and there’s a push to catch up. A number of standards have either recently been enacted or will be enacted in the near future, including:

  • The furnace efficiency rating went into effect in the summer of 2019.
  • HVAC compressor EE regulations are going into effect in 2023, along with the elimination of ozone depleting refrigerants.
  • A new DOE initiative to improve energy consumption in ceiling fans showcases how regulations like the above are researched and established.

If you look back a number of years ago, washing machines used what is called a permanent split capacitor motor. Those motors were roughly 60% efficient overall. Within the last couple of years, we’ve started to see more washing machines become Energy Star–rated through the transition to a permanent magnet or BLDC motor, which are roughly 80% efficient. And with the introduction of those types of motor technologies, you also have to incorporate some type of drive for those motors, known as an inverter.

This new type of motor technology is more efficient in and of itself. With the introduction of inverters, variable-speed motor control can be enabled, further improving efficiency and helping meet Energy Star requirements. Taking an HVAC system as an example, historical systems had a single-speed fan, so regardless of the cooling or heating load required, it would always run at the same speed. By introducing variable-speed motor capabilities, the motor can run at 50% of its actual power rating, providing a 90% reduction in energy usage. A motor running at 85% of its actual power rating provides a 50% reduction in energy usage.

There’s another benefit of inverterization: Because of its ability to run the motor at variable speeds to meet just the heating/cooling load demand, the appliance will actually last longer. The reason behind this is that when the appliance has only one speed, it runs hotter and harder. This is typical of an inverterized refrigerator that will run at 20% of its rated power for its lifetime minus the initial two-hour cooldown cycle when you first plug in a new refrigerator. This helps improve the longevity of the compressor and refrigerator, as well as offer significant energy savings though light load efficiency gains.

This shift to inverterization is challenging for manufacturers, as many do not have in-house power electronics teams. Their expertise lies in knowing how to make electromechanical systems. Up until a couple of years ago, appliances didn’t have inverter drives and permanent magnet or brushless DC motors. In fact, there was basically no semiconductor content outside of the user interface. With the introduction of inverterized motor control, the content of current appliances has shifted drastically. A typical inverter consists of six switches, three half-bridge drivers or a three-phase inverter driver, a motor control IC, current sensors/shunts, and an auxiliary power supply.


The typical inverter consists of six switches, three half-bridge
drivers or a three-phase inverter driver, a motor control IC,
current sensors/shunts, and an auxiliary power supply.

Another challenge that manufacturers face is cost. Adding new technologies into appliances can drive up the cost by 15% to 20%. This can be a competitive disadvantage to add energy efficiency, as a consumer shopping for a new washing machine or refrigerator will likely balk at one that is 15% to 20% more expensive and will likely go with the cheaper version. It took tax rebates as an incentive to the consumer to offset the cost and jumpstart the Energy Star trend. That concerted effort helped to start educating consumers on what Energy Star appliances are and the lifetime cost of ownership justifying the increased upfront cost.

The semiconductor industry is the driving force enabling these increases in efficiency, and it’s not the first time something like this has happened. Taking a look at lighting, the transition from incandescent bulbs into compact fluorescents and then eventually to LED bulbs was the result of a progression in semiconductor technology over the time period. That innovation revolutionized the market and significantly reduced energy use associated with lighting in the house. It is these same types of trends that are now transitioning into major home appliances. As more energy regulations happen across industries, there will be an increase in the amount of semiconductor content in products. It will be the progression of semiconductor technology that will again lead the way.

The semiconductor industry has been following potential regulations in the Americas since the beginning. As they become law, the semiconductor industry works with OEMs to understand what the regulations mean and the solutions available to them to bring their next generation of product to market.

This can be daunting to a manufacturer that doesn’t have expertise in some of these new technologies. That’s why it’s critical for OEMs to have a true partnership with a semiconductor company and utilize their expertise. The semiconductor partners tend to create reference design solutions targeted at specific applications. These reference designs can offer an OEM an 80% complete hardware and software solution, which is supported by schematic and board layout files. The OEM can then take that and productize it into a solution that fits the form factor of their end applicant and, by doing so, take ownership of it in terms of the application requirements for their product space. Having the right semiconductor partner can ultimately reduce their time to market.

According to IEA, appliances account for 15% of global final electricity demand, or one-quarter of electricity used in buildings. As attention increasingly focuses on climate change, energy efficiency in appliances will be a key way to curb energy consumption and thus lower greenhouse gases. Appliance OEMs can expect more regulations and energy standards in the near future. Partnering with the right power semiconductor company will be critical to keeping pace.

—Michael Williams is Sr. Product Marketing Manager, Industrial Power Control, Infineon Technologies Americas Corporation

For More Information:

Semiconductors: Powering the Future of Everything Efficiently from Energy Generation to Consumption

Understanding the Semiconductor Shortage

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>> This article was originally published on our sister site, Power Electronics News.


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