January 2009

Boosting energy efficiency

Electronics saves energy

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As demand for energy continues to rise around the world, reserves of fossil fuels are becoming depleted. At the same time, discussions about climate change resound with ever louder calls for reducing CO2 emissions. Thus, the trend toward greater energy efficiency is exerting a growing impact the development of technological systems and equipment.

EPCOS is continuously developing solutions that contribute indirectly or directly to saving energy in industrial installations, motor vehicles, home appliances and other electronic devices.

Savings success in energy generation and transmission

Wind power plants become considerably more efficient when fitted with capacitors for power factor correction (PFC). They improve the power factor of the installations from between 0.2 and 0.4 to values between 0.8 and 1. EPCOS components are also used in photovoltaic systems: power capacitor chips in inverters stabilize the DC voltage supplied by solar cells. These capacitors are manufactured for specific applications and their terminals are an exact fit for IGBT modules from leading manufacturers (Fig 1).

PCC fits IGBT modules from most semiconductor manufacturers.

High-voltage DC (HVDC) transmission systems offer comparatively low-loss, economic and environmentally friendly power transmission over long distances, such as from offshore wind parks to the coast or from the mainland to oil drilling platforms and islands. HVDC is a technology trend that is also being used in San Francisco’s Transbay project that is being built by our customer Siemens PTD for the power utility Trans Bay Cable LLC. EPCOS is the sole supplier of power capacitors for this project. These products have a typical capacitance of 4000 to 5000 μF and are designed for rated DC voltages of up to 2800 V DC. Their current handling capability extends to 450 A.

Some 48 TWh of electrical energy can be saved annually by PFC measures in the European Union alone, according to German engineering association ZVEI. This corresponds to the output of four large power plants. As market leader, EPCOS offers all key components for PFC systems in its program. They include capacitors of the PhaseCap® series as well as power factor controllers and capacitor contactors (Fig. 2). Dynamic PFC is particularly fast, with ultra-short reaction times of only 5 ms. It allows an effective response to fluctuating loads such as those occurring in welding equipment or crane motors. EPCOS offers high-performance thyristor modules and power factor controllers for this purpose. “With our PFC solutions, we have successfully implemented a whole series of major projects worldwide,” says EPCOS Sales Head Thiele. “Among our projects in China, we have equipped the country’s largest shipyard, the China State Shipbuilding Corporation, and various Olympic competition sites with our PFC products.”

PFC controllers of the BR6000 family provide automatic control of dynamic PFC systems.

Energy-saving drives for industrial installations

Variable-speed drives are increasingly being using in industry to save energy. They require frequency converters in which rugged aluminum electrolytic capacitors - often with screw terminals - play a key role in storing and smoothing the voltage in the DC link. EPCOS is world market leader in this product area.

Improving the energy balance of vehicles

Automotive sensors play a crucial part in improving the energy balance of motor vehicles. NTC sensors from EPCOS measure the temperature of the incoming air as well as that of the exhaust, oil and coolant. Controllers evaluate this data to optimize engine operation. These sensors improve the control process in air-conditioning units. EPCOS has developed new evaporator sensors that are much more reliable than their predecessors, with only half the response time – less than 4 s in air currents – making them equally suitable for new CO2 air-conditioning systems.

EPCOS has also been active in the field of pressure sensors for two years. “We offer a considerably extended portfolio of sensors from a single source and have consolidated our position in the growth market of sensors,” explains Thiele. EPCOS now supplies miniaturized and extremely rugged differential pressure sensors used to regulate exhaust-gas recirculation systems in order to noticeably lower the emissions of internal combustion engines.

EPCOS is also world market leader in piezo-actuators for fuel-saving piezo injection systems in gasoline and diesel engines. Thanks to this technology, the fuel can be more finely dosed and the injection more precisely controlled, assuring particularly efficient and low-pollution combustion.

Savings potential in lighting technology

Ballasts assure the reliable operation and long service life of energy-saving lamps. Here too, film capacitors, inductors, transformers and thermistors from EPCOS play a key role. Together with leading semiconductor manufacturers, the company has developed a series of reference designs for electronic ballasts.

Energy-efficient household and consumer electronics

Induction cookers can save considerable energy because they transfer heat very efficiently via electromagnetic fields. Their efficiency is around 90 percent, far above that of gas cookers (40 percent) or conventional electric cookers (up to 60 percent). EPCOS has become an established supplier of key components for induction cookers. These include film capacitors, chokes, transformers, thermistors and varistors. A newly developed NTC thermistor located in the center of the cooking field ensures that the set temperature is precisely maintained.

Anyone who replaces a refrigerator-freezer combination from the year 1990 with an upgrade appliance of energy efficiency class A++ will save about 80 euros per year for a 270-liter model, according to the German energy agency (dena). But before a refrigerator can join this premium class in terms of energy efficiency, its compressor must convert as much electrical energy as possible into cooling the icebox. The motor-run capacitors of the MotorCap P2 Compact series as well as motor-start PTC thermistors from EPCOS contribute to this process (Fig. 3). They increase the torque of the compressor motor, while on-state PTCs have reduced power dissipation. With the aid of these two components alone, a refrigerator can save around 50 kWh a year.

MotorCap P2 Compact capacitors from EPCOS help reduce the power consumption of refrigerators.

More than 20 billion kWh is wasted each year by stereos and TV sets in standby mode in Germany alone. This is equivalent to about one and a half times the energy consumed by the city of Berlin in a year. This high consumption in standby mode is due to ferrites, whose efficiency reaches its maximum under load. To compensate for this, EPCOS offers the N51 material, which reduces the standby losses of the switched-mode power supplies for these devices. EPCOS has also developed calculation models designed to minimize the ferrite losses of power supplies. Developers can obtain this tool free of charge from the EPCOS website (www.epcos.com/tools).

Innovation for more energy efficiency

Reduced energy consumption is a competitive advantage for information and communication technology as well. “Thanks to our entry in the sector of RF-MEMS technology, EPCOS will offer new solutions for reducing the power consumption of mobile phones, and thus enable significantly longer talk and standby times,” adds Thiele, looking ahead. EPCOS is currently developing adjustable microcapacitors that can match the antenna impedance of multiband mobile phones to diverse operating conditions. On the one hand, these MEMS-based RF networks improve the transmission quality of the phones; on the other, they reduce the energy consumption of these devices by up to 25 percent.



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