Current sensor HLSR 20-P Introduction

Creation Date

The HLSR 20-P is a current sensor manufactured by LEM, part of their HLSR-P series. It utilizes open-loop Hall Effect technology and is specifically designed for precise electronic measurement of DC, AC, and pulsed currents.

Here’s a detailed introduction and explanation of the HLSR 20-P’s function:

Introduction to HLSR 20-P

  • Operating Principle: The HLSR 20-P operates based on the Hall effect principle. When current flows through the primary circuit of the sensor, it generates a magnetic field. A Hall element senses this magnetic field and produces a Hall voltage proportional to the magnetic field strength. This voltage is then processed and output. Being an open-loop design, the sensor doesn’t have internal closed-loop feedback for error correction, making it relatively cost-effective while still offering good performance.
  • Rated Current and Measurement Range: The HLSR 20-P has a rated primary current of 20 ARMS (Amperes Root Mean Square) and a measurement range of up to $\pm$50 A. This means it can measure current bidirectionally within this range.
  • Output Signal: The sensor outputs a voltage signal, typically 2.5 $\pm$ 0.8 V, which is proportional to the primary current.
  • Power Supply Requirements: It requires an external unipolar DC power supply, typically +5V.
  • Isolation: The HLSR 20-P features galvanic isolation between the primary circuit (the current being measured) and the secondary circuit (the sensor output). This means the sensor can safely measure high voltages or currents without transferring these potentials to the control circuitry.
  • Accuracy and Response Time: At 25°C, its accuracy is typically $\pm$1% (relative to the rated current), and it has a very fast response time, usually 2.5 µs, making it suitable for applications requiring rapid response.
  • Operating Temperature Range: A wide operating temperature range, typically -40°C to +105°C, allows it to operate reliably in various industrial environments.
  • Physical Characteristics: The HLSR 20-P features a compact design suitable for PCB through-hole mounting (“P” stands for Through-hole). It occupies a small PCB area (approximately 3.87 cm²) and has a low height of only 12 mm, making it ideal for space-constrained applications.
  • Other Features: It boasts low power consumption, is factory-calibrated, and exhibits low offset and gain drift.

Function of HLSR 20-P

The primary function of the HLSR 20-P is to provide accurate, isolated current measurement and convert the current signal into an easily processable voltage signal for subsequent control, monitoring, or protection circuits. Specifically, its role is evident in the following areas:

  1. Current Monitoring and Control:

    • In power electronics equipment like inverters and servo motor drives, real-time monitoring of motor current is crucial for precise speed and torque control. The HLSR 20-P can provide these essential current feedback signals.
    • In battery-powered systems, it can monitor battery charge and discharge currents to optimize battery management and extend battery life.
    • In uninterruptible power supplies (UPS) and switched-mode power supplies (SMPS), it monitors input and output currents to ensure stable and reliable power operation.

  2. System Protection:

    • By monitoring current, the HLSR 20-P can help systems detect abnormal conditions like overcurrents and short circuits, triggering protection mechanisms in time to prevent equipment damage or hazardous situations.
    • In welding power sources, it monitors current to ensure the stability and safety of the welding process.

  3. Energy Management and Optimization:

    • In renewable energy applications, such as in combiner boxes and Maximum Power Point Tracking (MPPT) of solar inverters, the HLSR 20-P is used to monitor DC-side currents to optimize energy conversion efficiency.
    • Accurate current measurement enables precise metering and management of energy consumption.

  4. Circuit Isolation:

    • Its galvanic isolation property between the primary and secondary sides allows control circuits to be safely separated from high-voltage or high-current primary circuits, enhancing system safety and reliability.

In summary, the HLSR 20-P is a high-performance, compact Hall effect current sensor widely used in industrial, power supply, and renewable energy sectors, providing reliable current measurement solutions for various electronic devices and systems.