The new power system composed of photovoltaic power generation is an important part of achieving carbon peak and carbon neutrality, and it is bound to integrate with energy storage, promoting the development of integrated photovoltaic-storage-charging systems. With the rapid development of 800V new energy vehicles, fast charging piles will be integrated into the photovoltaic-storage-charging system in the future, forming a new power system or microgrid. On one hand, bidirectional charging and discharging at high voltage is a typical feature of the new photovoltaic-storage-charging system. Silicon carbide devices, by upgrading module power and energy conversion efficiency, will be widely used in super-fast charging infrastructure. On the other hand, new energy vehicles are the largest application scenario for silicon carbide power semiconductors. Silicon carbide, with its high voltage resistance, high temperature resistance, and high-frequency characteristics, is expected to rapidly replace silicon-based and IGBT in high-voltage systems, significantly improving vehicle performance and optimizing the overall vehicle architecture. In addition to charging piles and wireless charging, silicon carbide power semiconductors have multiple in-vehicle application scenarios, including motor controllers, onboard chargers (OBC), DC-DC converters, and air compressors.
Photovoltaic inverters convert the direct current generated by photovoltaic panels into alternating current for use in the power grid, and are the core components of solar photovoltaic power generation systems. The conversion efficiency of photovoltaic inverters directly affects the power generation efficiency of the entire photovoltaic system. As a wide bandgap semiconductor, SiC devices have the advantage of higher energy conversion efficiency, and their performance advantages are highly compatible with the iterative requirements of photovoltaic inverters. Compared to Si based devices, SiC can bring higher conversion efficiency and lower energy loss to photovoltaic inverters, effectively reducing system size, increasing power density, extending device lifespan, and reducing production costs. At present, commercial photovoltaic systems mainly use two-stage photovoltaics. The function of the front-end (DC/DC converter) is to boost and MPPT, while the back-end (DC/AC) realizes inverter grid connection and is resistant to high voltage SiC; MOSFETs and high current SiC diodes will showcase their capabilities.
The energy storage system improves the efficiency of power grid operation and reduces line losses caused by local electricity congestion during peak periods of the power grid. Energy storage systems can also reduce the need to build more power plants to meet peak demand in the electricity system. The core components of ESS are bidirectional DC/DC and DC/AC power conversion systems, which connect all power grids, photovoltaic panels, wind turbines, electric vehicles, and batteries together and achieve power conversion between them. SiC technology can achieve high-voltage, high-frequency, and high-efficiency solutions, which are key requirements for all energy storage systems. The energy storage system based on SiC devices will play a greater role in optimizing power distribution, stabilizing the power grid, smoothing power demand, and better utilizing renewable energy.
At present, fast charging capability (basically filling in 5-10 minutes) will be the last piece of the puzzle for new energy vehicles to fully replace fuel vehicles, and SiC will play an important role in it. More and more car companies are developing towards the 800V platform, which will inevitably introduce high-voltage and high-power modules in the field of charging piles. The traditional Si based and IGBT devices have low blocking voltages, and the combination of multi-level topologies will pose challenges to size and efficiency. SiC based ACDC converters can effectively solve these problems by using fewer devices, occupying less circuit area, and achieving higher peak efficiency. To introduce the 800V charging architecture, the charging efficiency of the charging station also needs to be further improved. The DC charging power will continue to increase from below 120kW to 350kW, or even 480kW. This means that it is necessary to smoothly expand the current mainstream 20kW and 30kW charging modules to 40kW or even higher power. Based on the technical features of high temperature resistance and high switching frequency brought by SiC solutions, it will assist in optimizing circuit design, device selection, air duct design, temperature protection, and achieve higher reliability of the module.
