1500V solar inverter at megawatts level in NPC1 topology enabled by high-density IGBT module

Centralized solar inverter applications in MW-class require high current rated modules or a high amount of paralleled modules. This paper presents a design concept for MW-class 1500V solar inverter in NPC1 topology realized in single-cabinet without paralleling, using standard half-bridge modules equipped with the latest generation of chip and joining technology that offer the highest current density and operation temperature. Gate drive turn-off control technique is used to reduce the voltage overshoot issue caused by the commutation inductance. Increasing output power density with forced air cooling under cabinet and heatsink constraints is achieved by increase operation junction temperature. The stack design concept will be explained, together with experimental results on IGBT switching and commutation performances, and thermal performance of the stack prototype.