Project brief
A single-phase 10kW transformerless grid-tied solar inverter for residential and small commercial applications. The power stage uses a 3-level NPC (neutral point clamped) topology with SiC MOSFETs for reduced switching losses and superior grid current THD below 3%. Advanced anti-islanding detection uses both passive (ROCOF, vector shift) and active (SMS) methods.
The case study follows solar input through conversion and grid supervision. It does not independently substantiate efficiency, harmonics, or grid-code claims.
The engineering challenge
Convert variable photovoltaic input into controlled grid current while supervising operating limits.
Engineering approach
- Connect photovoltaic tracking channels to the inverter's DC-side control.
- Coordinate switching control with grid sensing and current regulation.
- Integrate islanding detection, fault supervision, and energy logging.
Features & capabilities
- 10kW single-phase output, 200–800V DC input (MPPT range)
- 3-level NPC topology with SiC MOSFETs: 98.1% European efficiency
- Grid current THD <3% at rated power across load range
- Dual MPPT channels for partial shading tolerance
- Anti-islanding: ROCOF, vector shift, SMS — <100ms detection
- IEEE 1547-2018 and IEC 61727 compliance (voltage/frequency ride-through)
- Arc fault current interrupter (AFCI) per NEC 690.11
- Data logging: 5-min interval, MODBUS TCP to energy monitor
Software & engineering tools
SiC MOSFETs (Wolfspeed), STM32G4, active NPC driver, Altium Designer (6-layer), MODBUS TCP