BLDC Motor Controller Rotation Diagnosis via Additional Current
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Solution Overview
Problem
Existing BLDC motor diagnostic systems struggle to efficiently determine whether a BLDC motor is rotating, particularly in applications where size and weight reduction are critical, and newer fans with sleeve bearings do not comply with legacy ECU diagnostics thresholds.
Innovation Solution
A BLDC motor controller that applies an additional current when the motor is rotating, allowing for a greater difference in monitored signals between rotating and non-rotating states, thereby enabling easier discrimination using existing output pins and reducing system complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If sleeve bearings are used in BLDC motors to reduce noise and improve efficiency, then motor efficiency and noise performance are improved, but the motor cannot generate sufficient current signal for legacy ECU diagnostic thresholds
Solution Approach 1:
The patent introduces an intermediary current module that generates an additional current signal based on motor rotation detection. This additional current acts as a mediator between the motor's actual operation and the ECU's diagnostic requirements, amplifying the diagnostic signal without altering the motor's efficient sleeve bearing operation. The current module translates the motor's rotational state into a detectable current signal that meets ECU thresholds.
2Measurement precision
If 3-wire or 4-wire motors are used to provide digital RD and FG signals for accurate rotation detection, then diagnostic capability is improved, but motor size and overall vehicle weight increase
Solution Approach 1:
The patent makes the current module multi-functional by enabling it to serve both as a diagnostic signal generator and as part of the existing motor control architecture. The same current module that monitors motor operation also generates the additional current for rotation detection, eliminating the need for separate diagnostic wiring and components. This universal approach allows accurate rotation detection while maintaining the compact 2-wire motor configuration.
3Measurement precision
If larger and more powerful motors are used to ensure sufficient current for diagnostic thresholds, then diagnostic signal strength is improved, but motor size and vehicle weight increase
Solution Approach 1:
The patent changes the parameter of current signal generation by introducing an additional current component that is activated based on motor rotation detection. Instead of increasing motor power, the system changes the electrical parameter by adding a controlled current signal from the current module. This parameter change allows sufficient diagnostic signal strength while maintaining the original motor size and weight specifications.
Data Source
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AI summary
A BLDC motor controller (100) comprising a first terminal (113) for applying a first voltage and a second terminal (114) for applying a second voltage to obtain a driving current for driving a BLDC motor (120). The BLDC motor controller (100) comprises a remote control unit (110) which is adapted for monitoring a signal which is indicative for a current through at least the first (113) or the second terminal (114), the BLDC motor controller (100) is adapted for increasing the monitored current by applying an additional current. The additional current is different from zero if the motor is rotating. The BLDC motor controller (100) is adapted for determining whether the motor is rotating or not, based on the monitored signal.