Add-on Current Sensor Module for Power Modules
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Solution Overview
Problem
Current power modules in high power drive applications lack integrated current sensing capabilities, leading to issues such as high cost, complexity, power dissipation concerns, and space requirements, with customer-built solutions often relying on external core-based magnetic sensors that suffer from hysteresis, non-linearity, and saturation effects.
Innovation Solution
An add-on current sensor module that can be inserted into a sensor-ready power module, featuring a core-less magnetic sensor design with compliant pins and a pivoting element for easy assembly and flexible selection, allowing for individual testing and compatibility with high volume manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If core-based magnetic sensors are used for current sensing, then measurement capability is achieved, but hysteresis, non-linearity, and saturation effects occur
Solution Approach 1:
The patent removes the ferromagnetic core from the magnetic sensor design, extracting the problematic element that causes hysteresis and saturation effects. The core-less Hall effect sensor directly senses the magnetic field generated by current flow in the busbar without requiring a ferromagnetic core, thereby eliminating the harmful magnetic effects while maintaining measurement capability.
2Measurement precision
If integrated current sensing is implemented in power modules, then measurement precision improves, but device complexity and cost increase
Solution Approach 1:
The control board is designed to serve multiple functions: it provides control signals, processes measurements, and integrates the current sensing functionality through the add-on module. The add-on current sensor module uses the existing control board infrastructure, making the control board universal for both control and sensing tasks, thereby reducing overall system complexity.
Solution Approach 2:
The current sensing functionality is segmented into a separate add-on module that can be independently tested, calibrated, and replaced. This modular approach divides the complex sensing task into manageable components, reducing the complexity burden on the main power module while maintaining integrated sensing capability.
3Ease of manufacture
If add-on sensor module is pressed onto control board with air gap, then compliant pins are partially inserted, but connection stability is reduced
Solution Approach 1:
The compliant pins are designed to be dynamically adaptable during assembly. Initially, with an air gap present, the pins are partially inserted allowing for easy assembly and positioning. As the module body is pressed against the control board, the compliant pins automatically adjust their insertion depth and contact pressure, transitioning from a loose state to a stable connected state, thereby achieving both ease of manufacture and connection reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The add-on current sensor module provides flexible current sensing solutions with reduced yield loss and logistical complexity, enabling efficient current measurement in high power applications while maintaining cost-effectiveness and assembly simplicity.
Implementation Method 1
a core-less in-phase current sensor is a magnetic sensor that implements one or more sensing elements in proximity to a current rail such that a measurement can be obtained based on a magnetic field produced by a current flowing through the current rail
Data Source
AI summary
A method may include pressing a sensor module onto a control board such that the sensor module is at an initial position where an air gap is present between a module body of the sensor module and the control board such that compliant pins of the sensor module are partially inserted into the control board. The method may include mounting the control board on a power module to cause pins of the power module to be at least partially inserted into the control board and the sensor module to be at least partially inserted in the power module such that a protrusion is through an opening in a busbar. The method may include pressing the control board onto the power module to cause the pins of the power module to be further inserted into the control board, the sensor module to be further inserted in the power module, and the sensor module to be at a final position.