In power electronic systems, current is the core signal for assessing equipment operating conditions, safety, and energy efficiency. In precision testing scenarios such as EV three‑electric system testing, motor test benches, AIDC power supplies, and energy storage inverters, the zero drift, temperature drift, bandwidth, and linearity of current sensors directly determine the credibility of the entire set of test data. For a long time in the past, the high‑end precision current measurement field has relied heavily on overseas solutions. Meanwhile, domestic sensor teams have persistently tackled challenges in magnetic core materials, closed‑loop compensation algorithms, signal conditioning circuits, electromagnetic compatibility, and full‑temperature‑range calibration systems, achieving substantial breakthroughs in multiple underlying technologies. Domestic current sensors are gradually meeting the stringent operational requirements of industrial precision measurement, and the localization of high‑precision current sensors continues to accelerate.

I. Optimization of the zero-flux closed-loop architecture, addressing the pain point of zero-point drift

Zero-point drift is the most challenging engineering problem in precision current measurement. Fluctuations in ambient temperature, prolonged continuous power supply, and residual magnetization from magnetic fields can all cause zero-point offset; accumulated errors can distort data obtained during long-term aging and formation testing.

Domestic current sensor iteratively optimizes the closed-loop magnetic balance architecture and, combined with an in-house compensation demodulation algorithm, reduces zero-point drift to an extremely low level. In scenarios involving wide-range measurements of both small and large currents, the sensor no longer suffers from a sharp drop in accuracy at low-current levels. The same high-precision current sensor can detect faint leakage currents on the milliampere scale while also accurately measuring currents up to thousands of amperes, achieving consistent measurement performance across the entire range and resolving the industry-wide issue of traditional sensors—namely, poor accuracy when measuring small currents over a large range.

II. Core material modification and full-temperature-range compensation, significantly reducing temperature drift

Traditional magnetic sensing solutions suffer from variations in permeability and Hall element sensitivity with temperature; while performance appears good at room temperature, accuracy degrades rapidly under high- and low-temperature conditions.

The domestic team has continuously refined the soft magnetic core material formulation and annealing process, reducing the core’s inherent temperature sensitivity; coupled with a self-developed digital temperature compensation algorithm, they have established a multi-point temperature calibration model to perform high-order compensation for sensitivity drift and offset voltage. The domestically produced current sensor maintains stable measurement linearity across a wide temperature range of - 40℃ to +125℃, ensuring that even under conditions with drastic temperature variations—such as automotive applications, outdoor energy storage, and high-temperature test benches—the high-precision current sensor continues to deliver stable and reliable measurement data.

III. Signal Chain and Bandwidth: Technological Breakthroughs, Compatible with High-Frequency Power Electronics Testing

The third-generation semiconductors are driving switching frequencies ever higher, and the dynamic pulsed currents in power supplies and motor controls are placing increasingly stringent demands on sensor bandwidth and step response.

A domestically produced current sensor featuring an optimized compensation coil drive circuit and a multi-stage low-noise signal conditioning chain, which broadens the operating bandwidth, shortens the step response time, and enables synchronous acquisition of DC, power-frequency, and high-frequency pulsed currents. In inverter dynamic testing and motor transient impact tests, this high-precision current sensor can reproduce current waveforms without distortion, resolving previous issues of high-frequency signal distortion and phase lag, thereby meeting the requirements for testing the dynamic characteristics of power devices.

IV. Electromagnetic Compatibility and Isolation Insulation Design, Adaptable to Complex Industrial Electromagnetic Environments

The industrial field and the interiors of high-power test benches are rife with strong magnetic fields and high-voltage common-mode interference; ordinary sensors are highly susceptible to magnetic-field interference from adjacent phases, introducing additional measurement errors.

The domestically produced current sensor has been optimized across multiple dimensions—including magnetic shielding structure, PCB routing, and shielding grounding strategies—to suppress external stray magnetic field crosstalk. At the same time, the insulating frame and creepage distance design have been refined to enhance isolation withstand voltage and surge tolerance, meeting IEC safety standards. In strong electromagnetic environments such as parallel operation of multiple motors and high-power power supply testing, this high-precision current sensor continues to maintain a high signal-to-noise ratio, reducing on-site debugging complexity.

V. Full-Link Calibration Process and Engineering Implementation, Achieving Stable Mass-Production Consistency

The laboratory prototype exhibits excellent performance metrics, but this does not guarantee stability in mass-produced products. For high-end sensors, the greatest challenge lies in controlling the dispersion of performance parameters across individual units during large-scale manufacturing.

Domestic manufacturers have built automated multi-point calibration production lines and established standardized processes for magnetic core screening, magnetic balance calibration, and high- and low-temperature aging screening, minimizing inter-unit parameter variations. From magnetic core processing, winding, and circuit soldering to whole-unit aging, domestically produced current sensors achieve full-process controllability, breaking free from reliance on overseas core components while shortening delivery cycles. They also support customized development of aperture sizes, measurement ranges, and output interfaces, adapting to diverse non-standard applications such as three-electric system testing and laboratory power measurements, thereby enabling large-scale, stable supply of high-precision current sensors.

Finally

The technological breakthrough of the domestically produced current sensor is not merely a pursuit of individual parameters, but rather a systematic improvement encompassing materials, magnetic circuits, circuitry, algorithms, and mass-production processes. From precision laboratory measurements to new-energy power test benches and energy-storage equipment monitoring, high-precision domestic current-sensor solutions are providing a reliable option for industrial power measurement.