A current sensor is a detection device that can sense the information of the measured current and transform the detected information into standardized electrical signals or other forms of information outputs according to a certain law, in order to meet the requirements of information transmission, processing, storage, display, recording and control. Current sensors can be categorized into shunts, electromagnetic current sensors, electronic current sensors, and TMR magnetic sensors according to different measurement principles. Electronic current sensors include Hall current sensors, Rokovsky current sensors, and inverter power sensors (for voltage, current and power measurement), which are specialized for inverter power measurement.
Detecting the working current of the motor single control line through the current sensor, optimizing the control timing to achieve the effect of energy saving, and at the same time preventing damage to the motor due to overcurrent.
Figure: Application of current sensors in new energy vehicles
Hall Current Sensor Testing
In the process of research and development and use of Hall current sensors, it is particularly important to measure the response speed, linearity, accuracy and other characteristics of the device, which is of great significance to ensure the stable and reliable performance of the device as well as to guide the selection and use of the device.
linearityThe degree to which the output signal (secondary current IS) is proportional to the input signal (primary current IP) within the measurement range. For example, if the output signal is 4V (or 50mA) when the current is 40A, the output signal should be 2V (or 25mA) when the current is 20A, these are ideal values, the actual output signal should be 2V (or 25mA) when the current is 20A.The current sensor's linearity is expressed by the linearity error. The smaller the linearity error value, the higher the detection accuracy.
accurateCurrent Sensor Accuracy Test: The degree of deviation of a current sensor's test value from its true value. The accuracy of the current transducer test depends on the performance of the device itself and also on the accuracy of the standard test source used for the calibration. Response time: There is a delay between the rise time of the output signal and the rise time of the actual signal, which is called the response time, i.e. the time difference between the output signal (secondary current IS) and the input signal (primary current IP).
temperature driftThe output of a current sensor can deviate when the temperature of its operating environment changes. Measuring the stabilized output performance of the device at different temperatures is an important guideline for use.
Response BandwidthThe output amplitude of the current transducer decays to a specified proportional value, typically -1 dB or -3 dB, for a specified amplitude input signal and a specified frequency.
Figure: Linearity Test Curve
Figure: Response Time Test Curve
Purcells Current Sensor Test Solutions
CTMS Current Transducer Test System
The Purcell CTMS current transducer test system can be used to accurately measure the static and dynamic parameters of a wide range of current transducers (Hall current transducers, Roche coils, Pearson coils, etc.), with a single large current source of up to 1,000 A. The parameters to be tested include DC parameters such as temperature drift, zero error, linearity, etc., and AC parameters such as response time, bandwidth, and noise spectrum, etc. The CTMS consists of a test setup, an upper computer control system, and a test fixture. The CTMS current transducer test system consists of test equipment, host computer control system and test fixtures. The test equipment mainly includes DC high-current source equipment, step pulse current source equipment, wide-band high-current source equipment, spectrum meter, oscilloscope, current direction switching device, environmental temperature simulation device, sensor power supply device, data acquisition device, etc. The host computer control system mainly includes the control of the instrument. The upper computer control system mainly includes the control of the instrument, automatic data collection, automatic data saving, data generation and other functional modules, as well as the design of the test interface.
Figure: Purcell CTMS current transducer test system
Zero, sensitivity, linearity testing
Under standard power supply and ambient temperature conditions, the sensor output signal is measured in 10% steps (or in customer-specified current steps) at one test point with reference to the current sensor's range.
Response Time Testing
Output response time of a current sensor at a rated primary current value under standard power supply and ambient temperature conditions. For closed-loop Hall current sensors, response times are typically in the µs range. Therefore, a fast current output capability is required for the primary current output source used for testing. In addition, the circuit must be constructed so that the probes used to test the primary current signal and the output signal of the current sensor are connected to the oscilloscope to ensure that the signals are captured in the same location.
Temperature Drift Test
Output signal characteristic curve under temperature. Test the output signal characteristic curve of the current sensor at different ambient temperatures under standard power supply conditions.
Frequency Bandwidth Test
The characteristic curves of the current sensor output signal response were tested at different frequency bandwidths of sinusoidal waveforms under standard power supply and ambient temperature conditions.
High Current Pulse Power Supply HCPL100
HCPL100 is a high-current, high-precision, wide measurement range special test power supply made by Wuhan Purcell, featuring high output current (1000A), steep pulse edge (15μS), and support for output polarity switching, etc. HCPL100 is a high-current, high-precision, wide measurement range special test power supply.
fixture (machining)
Different fixing fixtures are designed for different package forms to meet the testing of conventional packages, such as QFN, SOIC, SOICW, PFF, PSF and core-through type.
If you need to get the detailed system construction plan and test line connection guide, welcome to call us for consultation!
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