Through the internal comparison of the above three Huawei servers, we found that the PCB size of the bottom layer of the three models is the same. The internal space of the 900W and 1200W power supplies looks relatively spacious, and they are respectively connected to larger aluminum-based heat sinks to improve the power system. cooling capacity. Due to the limited internal space of the power supply, designers try to reserve enough space for other components as much as possible. The two PFCs are designed as a whole, sharing a set of magnetic cores and sealing together.

With the digital transformation of the industry, the number of base stations and data centers is gradually increasing, and the energy pressure is increasing. According to relevant information, by 2025, the number of communication sites is expected to increase to 70 million, and the annual electricity consumption will exceed 670 billion kWh; the data center will increase to 2400 -ic/" title="2400 model">2400-ic/" title="Model 2400">2400-ic/" title="Model 2400">2400-ic/" title="Model 2400">2400-ic/" title="Model 2400">2400-ic/" title= "Model 2400">2400-ic/" title="Model 2400">2400-ic/" title="Model 2400">2400-ic/" title="Model 2400">2400-ic/" title="2400 Model">2400-ic/" title="Model 2400">2400-ic/" title="Model 2400">2400-ic/" title="Model 2400">2400-ic/" title="Model 2400" >2400-ic/" title="Model 2400">2400-ic/" title="Model 2400">2400-ic/" title="Model 2400">2400-ic/" title="Model 2400">2400 Ten thousand racks, the annual power consumption exceeds 950 billion kWh. Billionaires' electricity consumption is worrying. In the context of "double carbon", energy conservation and emission reduction have become the common goal of all mankind, and have triggered an energy revolution in all walks of life.

Starting from the communication business, Huawei has deployed base stations, servers, etc., adhered to the concept of "simple, green, intelligent, and safe", and launched a variety of server power products.

Recently, the blog of Bilibili @machine soul released a video about the dismantling of the power supply, which attracted me deeply. The 3000W titanium-grade gallium nitride server power supply produced by Huawei was removed. Blogger said that the PAC3000S12-T1 power supply is a product launched by Huawei a few years ago, with high power density and a system conversion efficiency of up to 96%.

Analyzing Component Layouts to Reveal High Power Density Secrets

According to relevant information, it is found that the BAT54CWT1 Huawei uses a variety of products, the output voltage is 12V, the power range provided by this product ranges from 900W to 3000W, the package size is 68mmx183mmx40.5mm, the length of 183mm is a lot, and the volume is controlled. It is 490.62mm3, which is much shorter than the industry average of 265mm. The power density can even reach 6.114W/mm3. However, the power density of traditional consumer GaN power supplies is only 1.1W/mm3, which is also more than 50% higher than that of dedicated server power supplies. With 90~264V AC voltage and 180V~300V DC voltage input, 12V/243.9A output.

How to make the power density of PAC3000S12-T1 reach 6.114W/mm3? Through the internal comparison of the above three Huawei servers, we found that the PCB size of the bottom layer of the three models is the same. The internal space of the 900W and 1200W power supplies looks relatively spacious, and they are respectively connected to larger aluminum-based heat sinks to improve the power system. cooling capacity. The 3000W power supply has canceled the design of the heat dissipation plate inside, and adopts the method of PCB cross-cutting and vertical splicing, which maximizes the limited space utilization rate, and is filled with components. MLCC capacitor stitch welding is also used at the output end of the power supply. Design, as a whole, this power supply is very compact.

Due to the limited internal space of the power supply, designers try to reserve enough space for other components as much as possible. The two PFCs are designed as a whole, sharing a set of magnetic cores and sealing together. This also reflects the high power density.

The appearance and component layout of this power supply are very compact, but they are not messy at all. This also reflects the high level of Huawei's PCB design engineers. It is not only necessary to consider the EMC problem during component layout, but also how to arrange the EMC problem. Part of it took a lot of effort.

Internal depth, familiar with power structure and materials.

In terms of system circuit, the 3000W server power supply adopts a PFC+LLC power supply structure. The PFC structure it adopts is a staggered totem-pole PFC. Totem-pole PFC is a new form of PFC, which is the least used in existing circuit topologies, and has lower conduction loss and higher efficiency than traditional PFC topologies. High conversion efficiency.

The PFC totem pole has a total of 12 MOSFET modules, of which the high-frequency bridge arm uses 8 gallium nitride devices. The blogger speculates that the 8 gallium nitride MOSFETs are GaNSystems' GS66516T650V enhanced gallium nitride MOSFETs, which are packaged in low-inductance GaNPX. On-resistance is only 25mΩ. Using four silicon-based MOSFETs with an on-resistance of 28mΩ, Infineon's IPT60R028G7 achieves the maximum on-voltage by connecting two in parallel and cross-connecting each other. The PFC main control chip is STM32F334, which is dedicated to ST dedicated power conversion applications.

The LLC circuit adopts the LLC resonant half-bridge structure, and 4 MOSFETs are used as the PFC circuit. Infineon's quasi-resonant flyback PWM controller ICE2QR2280G is used as the auxiliary power supply. The controller has a digital frequency reduction function, which can ensure its stable operation when the load is small, and has good conversion efficiency and anti-electromagnetic interference performance. The 12V output adopts Toshiba's N-channel MOSFET, and its on-resistance is only 0.41mΩ.

After dismantling, it was found that this Huawei power supply is full of materials, stacking 12 gallium nitride MOSFETs. The price of GS66516T on the component trading platform is 275 yuan per piece, and the total value of only 12 gallium nitride MOSFETs reaches At 3300 yuan, Huawei's stacking capacity is really amazing. When designing this power supply, the cost issue was not considered.

Heat dissipation and efficiency

Uninterruptedly generating heat while supplying power, as temperatures rise, power supply performance suffers, shortening the life of power components, which can eventually lead to system failure. Therefore, thermal management of energy is very important.

After disassembly, I found that there is no heat sink installed inside the power supply. All heat dissipation is achieved by a 12V/4A fan next to the power input. This fan can turn 4W at full speed. After all, the output power of this power supply is achieved. Up to 3000W, can not be underestimated. But the disadvantage is that the noise of the fan is also very loud when running at high speed.

Why is the "heavy cost" in energy efficiency only 96%? Since the heat sink adopts a 12V/4A fan, the fan loss is large in the running state. In addition, since the output current is as high as 243.9A, the conduction loss of the synchronous rectification link is extremely high, and at the same time, a high copper loss will be caused when a large current of 243.9A passes through the transformer. The loss in three aspects is the main reason why the efficiency of this type of power supply cannot be improved.

Epilogue

Although this is a product from a few years ago, it can meet the current development needs of server power supplies in terms of high power, high density, and high efficiency. Coupled with the dislocation of spare parts layout, it can be seen that Huawei's R&D team is still quite powerful. .