Global chip shortage? How to choose a domestic alternative solution for communication charging station motherboards?

Global chip shortage, domestic replacement of AC charging station motherboards, with the core consisting of four major components: main control MCU, power devices, communication modules, and metering chips, is a three-dimensional balance of performance, reliability, and supply chain stability.

Main control MCU

• Zhaoyi Innovation GD32F407/F470 is pin compatible with STM32F4, with a higher clock frequency (240MHz) and lower price. Simply port and modify the startup file to run. However, the industrial level validation time is not as long as ST, and the linearity of some ADC models is slightly poor, with occasional watchdog resets at high temperatures.

• The National Technology N32G455 is equipped with national security SM2/SM3/SM4 hardware acceleration, which meets the security requirements of the State Grid and is currently undergoing vehicle certification. Suitable for local encrypted markets such as State Grid's centralized procurement and export to the Middle East.

• Selection: GD32F470 is a fast replacement for STM32F407 for 7kW/11kW universal piles; The State Grid project may require the selection of N32G455 in the national security market.

power device

• San'an Optoelectronics, Silan Microelectronics, and Huarun Microelectronics have mass-produced SiC MOS at 650V/1200V, with a yield rate of over 80% and a price 30-50% lower than imports.

• But the switch loss is 10-15% higher than Wolfspeed/Infineon, and the conduction resistance drift is greater at high temperatures.

• Selection: The 7kW charging pile is not sensitive to efficiency and can be directly replaced domestically. If the 22kW pile achieves an efficiency of over 97%, imported and domestically produced hybrid PFC high-frequency switching tubes and LLC synchronous rectification are imported to balance cost and performance.

Communication module

• Mobile Communications Cat-1/Cat-4 module (EC200S) has replaced some models of Quectel, with independent supply chain and complete FCC/CE certification. Some operators in North America still specify Quectel, which needs to be confirmed in advance.

• Guanghetong L610 has better power optimization and is suitable for solar powered off grid piles.

• Selection: domestic and Southeast Asian migration; If the operator in North America does not specify an available mobile remote replacement, Quectel dual suppliers will be retained.

Measurement chip

• Beiling BL0939 supports three-phase metering, harmonic analysis, and temperature compensation, with an accuracy of 0.5 level and a price 40% lower than imported ADE7758. However, small currents (<50mA) have high sampling noise and amplified errors during the trickle stage.

• Juquan Optoelectronics HT7038 has a better dynamic range and is suitable for V2G bidirectional metering.

• Selection: BL0939 is more cost-effective for ordinary 7kW/11kW piles; Choose HT7038 for V2G or high-precision billing.

Supply chain risk

• The real risk of domestic chips is not performance, but production capacity fluctuations. In the 2021-2022 shortage wave, domestic MCUs have also increased their prices tenfold and delivery times have been extended to 52 weeks.

• When replacing, it is necessary to confirm whether there is a second domestic supplier backup (GD32 out of stock switch N32); Whether to sign a long-term supply agreement (LTA) to lock in production capacity prices; Have you evaluated the sources of wafer fabs (SMIC, Huahong, Jita, etc.) to avoid restrictions on a single wafer fab.

Certified compatibility

• After the replacement of domestic chips, EMC、 Safety regulations and measurement accuracy certification need to be retested.

• GD32 is compatible with STM32 pins, but the internal clock tree and ADC sampling timing are different, which may result in radiation or conduction exceeding the standard.

• Suggest retesting EMC for all items after replacing the core, without conducting differential testing.

Conclusion

Domestic substitution is not just cheap, it is a trinity of performance that meets the scenario, supply chain backup, and certification that can pass. The conditions for domestic substitution of 7kW charging piles are mature, and it is recommended to import and mix domestically produced 22kW high-end piles while retaining flexibility. The safest strategy is to have hardware design compatible with dual suppliers, software abstraction layer shielding chip differences, and quick switching without stopping production when out of stock.

The communication charging pile control board produced by Xincheng Technology is of high quality and good price. Welcome to inquire and purchase!