Flex PCB Hall Sensor Layout for Precise BLDC Rotor Positioning
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Solution Overview
Problem
Existing BLDC motors require manual adjustments and labor-intensive processes for positioning and calibrating Hall-effect sensors, leading to inaccuracies in sensor placement and reduced motor efficiency.
Innovation Solution
The use of flexible and rigid PCB combinations to support Hall-effect sensors, allowing for automated placement and improved positional accuracy, using surface mount sensors and reflow soldering, with flexible segments enabling precise angular positioning relative to rotor magnets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If through hole Hall-effect sensors are used with manual soldering, then the sensors can be positioned relative to the rotor magnets, but manual adjustment is required to ensure accurate detection and angular spacing is affected by manual placement
Solution Approach 1:
The patent replaces manual mechanical soldering operations with automated reflow soldering processes. The PCB assembly with pre-positioned surface mount Hall-effect sensors is placed in a reflow oven where automated heating and cooling cycles solder all sensors simultaneously, eliminating manual soldering while maintaining precise positioning achieved during PCB fabrication
Solution Approach 2:
The PCB is designed with pre-determined angular spacing and pre-positioned mounting locations for Hall-effect sensors during the PCB fabrication process. This preliminary positioning ensures accurate angular spacing before the sensors are attached, eliminating the need for manual adjustment of sensor positions and angles during assembly
2Reliability
If through hole Hall-effect sensors are used, then sensors can be mounted on a PC board, but hand soldering and positioning adjustment are required which reduces productivity
Solution Approach 1:
The patent replaces manual mechanical soldering operations with automated reflow soldering processes. The PCB assembly with pre-positioned surface mount Hall-effect sensors is placed in a reflow oven where automated heating and cooling cycles solder all sensors simultaneously, eliminating manual soldering while maintaining precise positioning achieved during PCB fabrication
Solution Approach 2:
The patent combines multiple sensors onto a single PCB assembly with predetermined angular spacing. The PCB integrates mounting structures for all Hall-effect sensors, connection wiring, and positioning features into one unified assembly that is installed as a single unit, reducing the number of discrete manual operations required
3Measurement precision
If manual adjustment is performed to synchronize sensor signals with stator coil current, then accurate rotor position detection is achieved, but the process is labor-intensive and time-consuming
Solution Approach 1:
The PCB is designed with pre-determined angular spacing and pre-positioned mounting locations for Hall-effect sensors during the PCB fabrication process. This preliminary positioning ensures accurate angular spacing before the sensors are attached, eliminating the need for manual adjustment of sensor positions and angles during assembly
Solution Approach 2:
The patent replaces manual mechanical soldering operations with automated reflow soldering processes. The PCB assembly with pre-positioned surface mount Hall-effect sensors is placed in a reflow oven where automated heating and cooling cycles solder all sensors simultaneously, eliminating manual soldering while maintaining precise positioning achieved during PCB fabrication
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
Reduces manual operations, enhances sensor accuracy, and enables a more compact and efficient BLDC motor configuration by utilizing automated assembly methods.
Implementation Method 1
Hall-effect sensors mounted in the motor are used to detect the position of the rotor of the motor
Implementation Method 2
using surface mount sensors and reflow soldering
Data Source
AI summary
Combinations of flexible and rigid PCBs are disclosed to support Hall-effect sensors in BLDC motors with improved positional accuracy and reduced manual operations. Use of one or more flexible PCB portions or segments allow the support and electrical connections for an array of Hall-effect sensors to be manufactured in a planar configuration using automated pick and place equipment. The flexible portions or segments of the PCB include conductive traces to transmit power to and receive a signal from the Hall-effect sensors. Pads to which the leads of a surface mount Hall-effect sensor will be mounted are formed on the flex PCB or on a rigid PCB segment connected to a flex PCB segment. Flexible PCB material allows the PCB assembly to transition from a planar configuration to one where the Hall-effect sensors are not in a common plane.