Current transformers and sensing magnetic components are used to measure, monitor, and protect power electronics systems. They may be small compared with main power transformers, but their accuracy and reliability can affect control behavior, fault detection, safety, and system stability.
BaoHui Tech manufactures transformers, inductors, filters, and custom magnetic components for power supplies, inverters, UPS systems, chargers, industrial controls, and related applications. Sensing magnetics should be selected with the same discipline as larger power components.
What a current transformer does
A current transformer produces a secondary current proportional to the primary current. It provides isolation and allows measurement of AC current without placing the control circuit directly in the power path. Current transformers are used in inverters, UPS systems, power supplies, motor drives, protection circuits, and energy monitoring equipment.
The accuracy depends on core material, turns ratio, burden resistor, frequency range, primary conductor arrangement, and saturation margin.
Burden selection matters
The burden resistor converts secondary current into a voltage signal. If the burden value is too high, the current transformer may saturate or distort the waveform. If it is too low, the signal may be too small for accurate measurement.
The burden should be selected together with the expected current range, frequency, ADC input, protection threshold, and allowed phase error.
Saturation affects protection
During overload or fault events, the current transformer must provide a usable signal long enough for the protection circuit to react. Saturation can reduce accuracy just when accurate measurement is most important.
Core size, material, turns ratio, burden, and expected peak current all affect saturation behavior. Fault current conditions should be included in the specification.
Frequency response and waveform
Power electronics waveforms are not always sinusoidal. Switching edges, pulse currents, and harmonic content can challenge sensing magnetics. The current transformer should be evaluated over the frequency range that matters to the control or protection circuit.
Layout also matters. Noise pickup, grounding, cable routing, and shielding can affect low-level measurement signals.
FAQ
Where are current transformers used in power electronics?
They are used in inverters, UPS systems, power supplies, motor drives, protection circuits, current monitoring, and energy measurement systems.
Can BaoHui Tech manufacture custom sensing transformers?
Yes. BaoHui Tech can support custom current transformers and sensing magnetic components based on current range, frequency, isolation, size, and accuracy requirements.
Good current sensing starts with a clear definition of normal current, peak current, fault behavior, frequency range, burden, and isolation requirement.