Significant upgrade in efficiency!China’s new charger energy efficiency standard starts project

On December 1, 2021, China’s compulsory power efficiency standard GB 20943 has completed the defense meeting. This standard upgrade is expected to include internal and external power supplies below kilowatts such as power adapters, PC power supplies, and server power supplies. The next stage will be publicized before the project is established.

The revision and upgrading of energy efficiency standards is an important measure to implement carbon peak and carbon neutrality in the power supply industry. This standard is under the jurisdiction of the National Energy Foundation and Management Standardization Technical Committee (SAC/TC20).

According to related information, the first edition of GB 20943 was issued in 2007, and the second edition was upgraded in 2013. The last update was nearly 10 years ago.

The current development of the power supply market is changing with each passing day, especially the emergence and popularization of fast charging and third-generation semiconductors, allowing power devices to achieve a great leap from the first-generation semiconductors to the third-generation semiconductors.

Especially in terms of power efficiency, the new environmental protection concepts of carbon peaking and carbon neutrality have been widely recognized. Power products, especially mobile phone chargers, have billions of units worldwide.

The release and implementation of the new GB 20943 power efficiency China mandatory standards will help improve the energy efficiency of power products and reduce carbon emissions.

The current GB 20943-2013 single output AC-DC and AC-AC external power supply energy efficiency limit values ​​and national standards for energy-saving evaluation values. It specifies the energy efficiency limit value, energy saving evaluation value, and experimental method of the external power supply that converts AC voltage into a fixed, single-channel low-voltage DC (not greater than 36V) or low-voltage AC (not greater than 36V) output voltage under 220V, 50Hz power supply conditions And inspection rules.

In terms of power range, the old GB 20943-2013 standard is only applicable to products with a rated output power of no more than 250W; and the latest upgraded standard is expected to further increase the power to the kilowatt level, with a considerable increase and a wider coverage.

The standard also defines the characteristics of a single output AC-DC external power supply.

a. Convert AC grid voltage to DC low voltage

b. Only a fixed DC output voltage is provided each time it is used

c. Use with electric load

d. It can be separated from the electric load

e. Connect to terminal products through wires, cables or other permanent connections

f. It is not equipped with any batteries.

According to the characteristics defined in the standard, the power supplies with built-in cables and fixed voltage output, such as router power supplies, laptop power supplies, mobile phone chargers, set-top box power supplies, and Display power supplies commonly used in our lives, are applicable to this standard.

The energy efficiency limit values ​​in the current standards are mandatory requirements, which stipulate the average power efficiency limit values ​​of power products, and there are different average efficiency energy efficiency limit values ​​for power supplies of different output powers.

It is worth mentioning that the new version of the GB20943 standard is expected to be further improved in terms of energy efficiency.

The energy-saving evaluation value is a recommended requirement, and the minimum average efficiency of the energy efficiency limit value is improved. When the average product efficiency reaches or exceeds the fixed energy-saving evaluation value, the product can be evaluated as an energy-saving product by the energy-saving product certification agency.

As a mandatory national standard, GB20943 also stipulates inspection rules. For terminal products, the energy efficiency limit value is used as a product field inspection item, and products that fail the energy efficiency limit value inspection are not allowed to leave the factory.

Industry significance

The mandatory energy efficiency standard upgrade for chargers is closely related to the current carbon peak and carbon neutrality. The upgraded GB20943 standard is expected to include all internal power supplies below kilowatts such as power adapters, PC power supplies, and server power supplies, expanding the traditional standard of 250W to kilowatts, covering many occasions in life.

The energy efficiency standards of GB20943 have kept pace with the advanced energy efficiency standards of the EU COC V5 and the US DoE VI. On the one hand, it can promote the efficiency of domestic power products in line with international standards and enhance product competitiveness. On the other hand, it can achieve mutual recognition with international standards and reduce trade barriers. In addition, the updated standards set energy-saving goals for enterprises, leading the healthy and orderly development of the industry.

The GB20943 standard is a mandatory requirement, which limits the conversion efficiency and standby power consumption of the power supply. It limits the lowest conversion efficiency and highest standby power consumption of the power supply, restricts the production of high-energy-consuming power products, and speeds up the elimination of backward products. And guide power supply manufacturers to produce high-efficiency, low-loss high-performance power supply products to enhance consumers’ awareness of energy conservation and promote the normal and healthy development of the power supply industry.

In recent years, with the development of fast charging and third-generation semiconductors, fast charging supports a variety of voltage outputs, and direct charging of mobile phone charge pumps requires the charger to dynamically adjust the voltage output at any time. The charger has many features that exceed the standard range of the agreement. As well as the improvement of people’s living standards in economic development, smart phones and laptops have been widely popularized.

In GB20943-2013, there is no provision for fast charging and computer power standards. With the development of the times, fast charging of mobile phones and personal smart terminals have been developed by leaps and bounds, and the number of power supplies and output power have been greatly improved. The new version of the standard is expected to include these power sources and formulate relevant mandatory national standards.

The upgraded version of China’s mandatory standards for power efficiency can greatly simplify the purchase process of chargers for domestic consumers, and can purchase them when they meet relevant standards. For power supply manufacturers, meeting domestic standards is equivalent to passing international energy efficiency standards, which can reduce certification costs.

The difference between GB and GB/T

There is a clear difference between the two, GB is a mandatory national standard, and GB/T is a recommended national standard.

Mandatory national standards are a form of laws passed by the state that clearly require that the technical content and requirements specified in some standards must be implemented, and it is not allowed to be violated or changed for any reason or in any way.

Mandatory national standards have legal attributes. Once a mandatory national standard is promulgated, it must be implemented.

Recommended national standards do not force manufacturers and users to use them, and national standards that promote the adoption of resources through economic means or market regulation are not mandatory.

How the charger improves energy efficiency

The improvement of the energy efficiency of the charger is actually the process of applying the updated technology to the charger, such as the application of new technologies such as charger energy consumption distribution, third-generation semiconductors, and high-efficiency power supply architecture to the charger, which improves the conversion efficiency of the charger. And heat, thereby reducing the size and heat dissipation requirements of the charger.

Charger energy consumption distribution

From the perspective of input, the energy consumption distribution of the charger can be divided into the loss of the input rectifier bridge, the switching loss of the primary switch tube, the transformer magnetic loss + copper loss, and the rectification loss. The way to improve energy efficiency is to reduce the loss of each link. Improve efficiency.

Third-generation semiconductor

The third-generation semiconductors, such as gallium nitride, are suitable for high-frequency switching. While there is no reverse recovery charge, they also have extremely low conductance. They are used in chargers to effectively reduce switching losses and conduction losses. Compared with traditional silicon MOS tubes, gallium nitride switching tubes have no body diodes, and therefore no body diodes to store charges. There is no need to charge and discharge the body diodes during high-speed switching, which significantly reduces switching losses and supports higher switching frequencies.

The increase in switching frequency can reduce the inductance of transformers and other devices and reduce copper loss. With the high-frequency optimized magnetic core material, the efficiency of the transformer can be improved while reducing the size of the transformer. The application of gallium nitride devices can improve the overall The conversion efficiency.

Silicon carbide diodes also belong to the third generation of semiconductors. Compared with ordinary fast recovery diodes, they have zero reverse recovery current. Used in PFC boost rectification, better reverse recovery time can greatly reduce switching losses, reduce temperature rise, and reduce EMI.

“The Fourteenth Five-Year Plan for the National Economic and Social Development of the People’s Republic of China and the Outline of Long-Term Goals for 2035”, in which the field of “integrated circuits”, especially the wide band gap semiconductors such as silicon carbide and gallium nitride, is the concern of industry professionals The third generation of semiconductors must be developed.

High-efficiency power architecture

The mainstream of traditional switching power supplies is the flyback topology. The flyback topology requires the use of an RCD absorption circuit composed of resistors, capacitors and diodes to absorb the leakage inductance energy of the transformer. Quasi-resonant flyback uses the Coss of the switching tube and outputs the energy stored in the capacitor. The transformer generates resonance, and when the energy stored on the switch tube is minimum, the switch tube is controlled to turn on, reducing the efficiency loss caused by Coss.

On the basis of quasi-resonant flyback, high-frequency QR adopts valley opening to reduce switching losses and support higher operating frequencies. Jump cycle and burst mode operation under light load can improve conversion efficiency. In recent years, a number of encapsulated gallium nitride devices have been mass-produced and have been widely used. The performance advantages of gallium nitride have been used to further improve power supply performance, meet high cost performance and wide range output, and have excellent standby consumption.

The ACF active clamp flyback topology is a new form of flyback topology. By adding a clamp switch with a capacitor, the leakage inductance energy dissipated in the traditional flyback RCD absorption circuit is stored. Before the main switch is turned on, the clamp switch is controlled to be turned on, the energy stored in the capacitor is released to the transformer, and the primary is reversely excited, so as to realize the ZVS switch of the main switch and improve the conversion efficiency. In addition, there is also the ZVS switch of the main switch tube by adding auxiliary windings, etc., and supports a wide range of output.

LLC is a double-tube half-bridge resonance, which uses resonance inductance, magnetizing inductance and resonance capacitance in series, hence the name LLC. It has the advantages of high working frequency, low loss, high efficiency and small size, which can increase the power density of the charger. Its resonant operation can realize soft switching in the full load range and reduce switching losses. It becomes an ideal choice for high frequency and high power density design, suitable for fixed voltage output, and has better EMI characteristics.

In the future, the power supply will also have the application and popularization of new technologies such as AHB and totem poles.

Active bridge rectifier

In recent years, with the continuous improvement of charger power and smaller size, the heating of the input rectifier bridge has become more and more obvious. In the disassembly of the charging head network, it was found that some chargers used active bridge rectifiers instead of traditional rectifier bridges. The principle of active bridge rectification is the same as that of synchronous rectification. A low-resistance MOS tube is used instead of the rectifier diode to eliminate the voltage drop loss on the rectifier diode.

Synchronous rectification

In the charger, synchronous rectification is used to control the ultra-low resistance MOS tube instead of Schottky diode rectification, which can effectively avoid the loss caused by the voltage drop of the output current in the Schottky diode and reduce the rectification loss. This is also the earliest used by people. A way to improve energy efficiency.

Which companies participated in the drafting of the standard

The GB20943 standard was developed by the China National Institute of Standardization, Shenzhen Hangjia Chiyuan Electric Co., Ltd., China Great Wall Computer Shenzhen Co., Ltd., Weikai Testing Technology Co., Ltd., National Electronic Computer Quality Supervision and Inspection Center, China Saibao Laboratory, Shanghai Quality Supervision and Inspection Technology Research Institute, Panasonic Wanbao Meijian Life Appliance (Guangzhou) Co., Ltd., Tongfang Co., Ltd., Sony (China) Co., Ltd., Epson (China) Co., Ltd., Nikon Imaging Instrument Sales (China) Co., Ltd. Beijing Branch, etc. Drafted by well-known companies in the industry.

Among them, Shenzhen Wattyuan Testing and Research Co., Ltd. compiled the energy efficiency data of chargers for full comparison and analysis, and provided effective data support for the establishment of the new national standard for energy efficiency.

Summarize

The updated version of the mandatory power efficiency standard will modify the outdated features in the traditional standard, and expand the charger category corresponding to the standard. It is expected to add power adapters, PC power supplies, and server power supplies to the internal and external power supplies of equipment below kilowatts. These widely used power supplies will be included in the scope of national mandatory standards to implement carbon peaking and carbon neutrality in the power supply industry.

The updated mandatory power efficiency standard will become a new power industry standard, which will have a positive impact on third-generation semiconductor applications. It will also stimulate the blossoming of new power architectures and accelerate semiconductor companies’ R&D investment in new power technologies. Technically realize energy saving and emission reduction, respond to the call for low carbon, and promote industrial upgrading.

my country is a big export country, and most consumer electronic products in the world are produced by my country, with a complete upstream and downstream industrial chain. The mandatory upgrade of power efficiency standards will specify the types of power products and parameters such as energy efficiency and standby power consumption in detail. It is equivalent to a power supply that has passed my country’s energy efficiency standards, and has also passed the corresponding European and American power efficiency standards, which can realize mutual recognition of international standards and reduce trade barriers.

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