Inductors for UPS Systems - PFC, Battery and Output Chokes

The inverter produces a pulse-width modulated voltage, not a sine wave. The output inductor, together with a filter capacitor, forms a low-pass filter that attenuates the switching carrier and its harmonics while passing the 50 Hz fundamental. It also limits the rate at which current can rise during a load fault, which gives the control and protection circuits time to act.

When a core saturates, its inductance falls sharply and the current ripple rises, sometimes enough to trip or damage the inverter switches. A UPS regularly sees currents above rated value during overload, transfer and load inrush. The choke should therefore keep a useful share of its inductance at the highest peak current expected, and we measure saturation current on every unit to confirm it.

Ripple and switching frequency decide it. Powder cores such as Sendust and High Flux handle large DC bias with gradual saturation and are widely used for PFC and output filters. Iron powder costs less but has higher core loss. Gapped ferrite gives the lowest loss at high switching frequency but saturates abruptly. We suggest a material after seeing your current waveform and frequency.

Yes, within our ranges. Ring-core common mode chokes are available up to 50 A, including three-phase power line filtering versions, and line filter inductors run from 500 mA to about 50 A, with line reactors for three-phase panels. Power inductors above the 25 A standard range are built as custom parts with heavier gauge or multi-strand copper to suit your current.

Stock toroidal inductors typically dispatch within 24 hours. For a custom UPS inductor, samples typically take 7 to 10 working days after the specification is agreed, and a first sample for lab approval is free. Around 10 pieces is a common prototype quantity, while production orders for custom parts typically begin between 100 and 1,000 pieces.