The traditional DC charging station topology circuit generally uses a three-phase AC 380V input voltage to pass through the PFC Vienna AC/DC circuit to obtain the DC bus voltage, and then passes through two full bridge LLC DC/DC circuits to output 200V to 1000V high voltage for charging new energy vehicles. The switching frequency of the PFC Vienna circuit AC/DC is around 40kHz, usually using 650V super junction MOSFETs or 650V IGBTs. The disadvantage is that there are many devices, complex hardware design, low efficiency, and high failure rate. The new generation of DC charging station topology circuit will upgrade the original PFC Vienna rectifier to a three-phase full bridge PFC rectifier using the second generation SiC silicon carbide MOSFET B2M040120Z. This will greatly reduce the number of power devices, simplify the complexity of control circuits, and reduce the inductance, size, and cost of inductors by increasing the switching frequency. The DC/DC full bridge LLC part has been upgraded to use the second-generation SiC silicon carbide MOSFET B2M040120Z DC/DC circuit, which can be optimized from the original three-level to two-level LLC. This can greatly simplify the topology circuit, reduce the number of components, and make control and driving simpler. Based on the high-frequency characteristics of the second generation SiC silicon carbide MOSFET B2M040120Z, the switching frequency of LLC circuits can be increased, thereby reducing the size and cost of magnetic devices. Due to the soft switching operation mode of LLC circuit, the losses are concentrated in the conduction loss of the switch tube. Due to the topological structure, the effective value of the current flowing through SiC silicon carbide MOSFET in LLC is half of the current of Si MOSFET, so the final conduction loss is greatly reduced. The new generation of DC charging station topology circuit using SiC silicon carbide MOSFET B2M040120Z can improve efficiency by about 0.3~0.5%.
Silicon carbide MOSFETs have high frequency, high voltage, and high temperature performance, making them the most popular wide bandgap power semiconductor devices in the field of power electronics. Applying silicon carbide MOSFET devices to replace traditional silicon IGBT devices in power electronic systems can increase the switching frequency of power circuits, improve system efficiency and power density, and reduce overall system costs.
The new products of the second generation silicon carbide MOSFET series of basic semiconductors are developed based on a 6-inch wafer platform, which outperforms the previous generation in terms of specific conduction resistance, switch loss, and reliability. On the basis of the original products packaged in TO-247-3 and TO-247-4, Basic Semiconductor has also launched silicon carbide MOSFET devices with auxiliary sources packaged in TO-247-4-PLUS, TO-263-7, and SOT-227 to better meet customer needs.
Highlights of Basic Semiconductor Second Generation Silicon Carbide MOSFET
Lower specific on resistance: The second generation silicon carbide MOSFET has significantly improved product performance by reducing the specific on resistance by about 40% through comprehensive optimization of the chip design scheme.
Lower device switching loss: The second generation silicon carbide MOSFET device has reduced Qg by about 60% and reduced switching loss by about 30%. The reverse transmission capacitor Crss is reduced, improving the anti-interference ability of the device and reducing the risk of misleading the device under crosstalk behavior.
Higher reliability: The second-generation silicon carbide MOSFET has achieved excellent product reliability performance through higher standards of HTGB, HTRB, and H3TRB reliability assessment.
Higher working junction temperature: The second generation silicon carbide MOSFET has a working junction temperature of 175 ° C, improving the high-temperature working ability of the device.
