UPS System Architecture
Typical power electronics configuration for UPS applications
Rectifier Stage
The input rectifier converts AC line power to DC for the inverter and battery charger. For higher efficiency, active rectifier topologies with power factor correction may be implemented using IGBT modules. The rectifier must handle line voltage variations and provide stable DC power.
DC/AC Inverter
The DC/AC inverter converts battery or rectifier DC power to clean AC output power. This stage must provide precise voltage regulation, fast transient response, and low total harmonic distortion (THD) to meet critical load requirements.
Static Bypass
The static bypass provides immediate transfer to utility power during inverter malfunction. This is typically implemented with thyristors for high reliability and fast switching capability. The bypass must seamlessly transfer without interruption to critical loads.
Key Requirements
- Continuous 24/7 operation with high reliability
- Fast response to power disturbances (within 4-10ms)
- Low THD for clean power output to sensitive loads
- High efficiency to minimize operating costs
FAE Technical Commentary
Expert insights on UPS applications
For static bypass applications, we recommend SEMIPACK thyristors with their proven reliability and fast switching capability. The thyristor's latching behavior provides robust bypass operation without the need for continuous gate drive during conduction.
When designing for high efficiency, utilize Semikron's latest IGBT technology with optimized VCEsat and switching characteristics. The balance between conduction and switching losses is particularly important for UPS systems that operate continuously at partial load.
For critical applications, implement redundant power semiconductors in parallel for N+1 reliability. Semikron's components are well-matched for parallel operation, simplifying redundant system design.