Uninterruptible power supply (UPS)
Working Principle
The core function of a UPS is to provide continuous, clean power during grid anomalies to ensure stable operation of connected equipment, achieved through the following mechanisms:
AC-to-DC Conversion
When grid power is normal, incoming AC is rectified to DC. This DC simultaneously charges the batteries and powers the inverter, which outputs clean AC to the load.
Battery Backup (DC Backup)
During grid failure, the battery bank instantly takes over (millisecond-level switching). DC power is converted to AC via the inverter, ensuring uninterrupted load operation.
Inverter Output (DC-to-AC)
Regardless of grid conditions, the inverter continuously converts DC to regulated, stable-frequency AC, eliminating voltage fluctuations for sensitive equipment.
System Architecture
Based on technology, UPS architectures are categorized into three primary types:
Standby (Offline) UPS
Operation: Directly passes grid power to the load when normal; switches to battery/inverter during outage (5-10ms transfer time).
Applications: Personal computers, small office equipment where brief interruptions are tolerable.
Advantages: Simple design, low cost, compact size.
Disadvantages: Transfer delay; outputs stepped approximation waveform instead of pure sine wave.
Line-Interactive UPS
Operation: Incorporates an Automatic Voltage Regulator (AVR) to adjust voltage fluctuations without battery engagement; switches to battery only during outages (2-4ms transfer time).
Applications: Small-to-medium business servers, network equipment.
Advantages: Enhanced voltage stabilization, faster battery transfer.
Disadvantages: Transfer delay persists; output waveform improved but not pure sine wave.
Online Double-Conversion UPS
Operation: 100% of incoming AC is rectified to DC, then inverted back to AC for output. Batteries connect directly to the DC bus, enabling zero transfer time.
Applications: Data centers, medical equipment, industrial control systems, and other mission-critical loads.
Advantages: Complete isolation from grid disturbances; outputs pure sine wave; zero transfer time.
Disadvantages: Higher cost; lower efficiency (~90-95%); requires thermal management.
Common Elements: All UPS types contain core components — Rectifier (charging), Batteries (storage), Inverter (discharge), Static Transfer Switch (bypass switching).
Market Development Trends
Lithium-Ion Dominance over Lead-Acid
Drivers: Higher energy density (50% smaller footprint), longer lifecycle (5-10 years vs. lead-acid’s 3-5 years), and rapid charging capabilities align with data center density demands.
Challenge: Higher upfront cost (offset by lower total cost of ownership).
High Density & Modular Design
High Density: Power density escalation (e.g., from 10kVA to 50kVA+ per rack) driven by data center space constraints.
Modularity: Scalable architectures (e.g., 10kVA modules expandable to 200kVA) with hot-swappable faulty modules, enhancing system availability.
Intelligence & AI-Driven Management
Predictive Maintenance: Sensors monitor battery health/capacitor aging; AI algorithms forecast failure risks.
Cloud Management: Remote multi-site UPS monitoring with automated efficiency optimization (e.g., dynamic efficiency adjustment based on load).
Energy-Efficiency Technologies
ECO Mode: Bypasses double-conversion during stable grid conditions (efficiency up to 99%), reverting during anomalies.
SiC/GaN Devices: Wide-bandgap semiconductors reduce inverter losses, boosting efficiency beyond 97%.
Integration with Renewables & Energy Storage
Integrated PV-Storage-UPS Solutions: DC bus coupling with solar PV or BESS enables peak shaving or extended backup.
Microgrid Stability Role: Large UPS units act as grid-forming assets to regulate local microgrid fluctuations.
Semiconductor Shortages & Supply Chain Restructuring
Challenge: IGBT/MCU shortages prolong delivery cycles.
Response: Multi-sourcing strategies and accelerated adoption of domestic power semiconductors.
The advantages of SMC
SMC, as a globally leading power semiconductor device manufacturer with nearly 30 years of history, can provide customers with the most advanced, efficient, and cost-effective third-generation silicon carbide MOSFETs and silicon carbide JBS diodes. In addition, SMC has unique experience in silicon-based power diode devices, and its best-selling high-power ultra-fast recovery diodes, high current Schottky diodes, and other products are highly praised by customers worldwide. SMC's power semiconductor devices can provide higher efficiency, better reliability, good delivery time, and competitive prices for your products. SMC's professional service team around the world allows you to experience the ultimate customer service experience and safeguard your product design.
GET A FREE SAMPLE
