A low resistance shunt is an electronic component that achieves high-precision current measurement by generating a small voltage drop proportional to the current. Its core advantage lies in the low resistance design, which can minimize interference with the tested circuit. The following are typical product application scenarios and technical logic analysis:
In the field of electric energy
Smart meters and grid monitoring
In the smart grid, low resistance splitters (usually below 0.1m Ω) are integrated into the current sampling module of the energy meter, achieving accurate measurement of AC/DC high currents through millivolt level voltage signals. Its low impedance characteristics can avoid phase errors caused by traditional transformers and meet the IEC 62053 international metrology standard.
High Voltage Direct Current Transmission (HVDC)
In the ± 800kV ultra-high voltage direct current project, the shunt is used for monitoring the current of the converter valve group, with a resistance as low as 0.01m Ω, and is combined with a high-speed ADC to capture nanosecond level current waveforms, ensuring the stability of the flexible direct current transmission system.
New energy vehicle industry
Battery Management System (BMS)
Inside the power battery pack, a shunt (with a typical resistance of 0.05m Ω) is connected in series to the main circuit. By collecting real-time charging and discharging currents (up to 1000A or more) and combining them with Coulomb counting method, SOC (remaining charge) estimation is achieved with an error controlled within ± 2%.
Motor Controller (MCU)
In the 800V high-voltage platform motor drive, the shunt monitors the waveform of the phase current, and reducing the resistance to 0.02m Ω can reduce the I ² R loss (such as only 0.8W power consumption at 200A current), while meeting the functional safety ISO 26262 ASIL D level requirements.
Industrial Automation and High end Manufacturing
Servo motor drive
In scenarios such as CNC machine tools and robot joints, the shunt (0.1m Ω) is directly embedded into the driver power module, and current loop closed-loop control is achieved through high-frequency sampling (>100kHz), with a response delay of<1 μ s, significantly improving dynamic performance.
Precision resistance welding equipment
The car body spot welding machine adopts a customized splitter (0.03m Ω), which outputs a 300mV signal under 10kA pulse current, and cooperates with PLC to achieve precise control of welding energy (error<1%), avoiding virtual welding or over melting.
Renewable Energy Systems
PV Inverter
In a centralized inverter, a shunt (0.02m Ω) monitors the DC bus current and optimizes the power conversion efficiency using MPPT algorithm. The temperature drift is less than 50ppm at an ambient temperature of 50 ℃, ensuring stable accuracy within a 25 year lifespan.
Wind power converter
The doubly fed wind turbine adopts a three-level topology structure, with a shunt (0.01m Ω) embedded in each IGBT module to detect the bridge arm current in real time, and cooperate with active short-circuit protection (ASC) to achieve fault isolation within 10ms.
Aerospace and Rail Transit
High speed rail traction system
In the CR400AF high-speed train traction converter, the shunt (0.005m Ω) monitors the traction motor current and outputs a 16mV signal at a continuous current of 3200A, meeting the EN 50155 standard for electronic equipment of rail vehicles.
Satellite power system
In the lithium-ion battery pack of low orbit satellites, a shunt (0.1m Ω) is used for monitoring the charging and discharging current, maintaining an accuracy of ± 0.1% at extreme temperatures of -55 ℃~125 ℃, ensuring the reliable operation of the Energy Management Unit (EPS).
Research and Medical Fields
Pulse power experiment
In high-power pulse devices such as electromagnetic guns and Z-clamps, a splitter (0.001m Ω) is used in conjunction with a Rogowski coil to achieve MA level transient current measurement, with a rising edge capture capability of up to 100kA/μ s.
Medical CT power supply
In the third-generation dual source CT high-voltage generator, a shunt (0.05m Ω) monitors the anode current of the X-ray tube and, in conjunction with DSP, achieves closed-loop control of 200kW power output to ensure image layer thickness accuracy<0.5mm.
Technological development trends
With the popularization of SiC/GaN devices, splitters are developing towards lower resistance values (<0.001m Ω) and higher bandwidth (>1MHz). At the same time, innovations such as manganese copper alloy+gold plating process and four terminal Kelvin connection are being adopted to further reduce thermoelectric potential (<0.1 μ V/℃) and inductance effect (<5nH), meeting the needs of emerging scenarios such as 800V platforms for new energy vehicles and 48V power supply for data centers.