Brushless DC Motor Control Module Reduces Processor Load
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Solution Overview
Problem
Brushless DC motor control devices face high processor load due to microcontroller interrupts from Hall sensors, leading to expensive and powerful microcontroller requirements, especially in applications like motor vehicle transmissions where multiple motors need simultaneous control.
Innovation Solution
Implementing an absolute encoder to derive incremental signals directly for a control module, reducing microcontroller burden by allowing asynchronous rotor position detection and using a separate control module for commutation, which includes hardware components for motor commutation, thus avoiding software-driven microcontroller interrupts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If block commutation with Hall sensors is used for motor control, then motor commutation can be achieved, but processor load becomes very high due to interrupts for each Hall state change
Solution Approach 1:
The patent extracts the commutation logic from the microcontroller and implements it in a dedicated control module (ASIC/FPGA). This separates the high-frequency commutation task from the microcontroller, eliminating interrupts and reducing processor load while maintaining high-speed motor commutation capability.
Solution Approach 2:
The patent replaces the software-based commutation control (running on microcontroller) with a hardware-based control module. This substitution moves the commutation function from the software domain to hardware domain, enabling parallel operation with the microcontroller and eliminating interrupt overhead.
2Productivity
If a powerful microcontroller is used to handle high processor load, then motor control performance improves, but cost increases
Solution Approach 1:
The control system is segmented into two independent parts: a microcontroller for high-level control tasks and a dedicated control module for commutation. This segmentation allows each component to be optimized for its specific function, enabling the use of a lower-cost microcontroller while maintaining overall system performance.
Solution Approach 2:
The control module acts as an intermediary between the Hall sensors and the microcontroller. It processes Hall sensor signals and generates commutation signals independently, shielding the microcontroller from high-frequency interrupts and enabling the use of a less powerful, lower-cost microcontroller.
3Productivity
If pre-commutation is implemented synchronously with motor commutation in one direction, then some performance improvement is achieved, but flexibility is limited
Solution Approach 1:
The control module dynamically adjusts the pre-commutation angle based on operating conditions such as motor speed and direction. This dynamic adjustment enables pre-commutation to work effectively in both rotation directions and at different speeds, significantly improving system flexibility while maintaining commutation efficiency.
Data Source
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AI summary
The invention relates to a control device (1) for a motor (2), especially a brushless DC motor. The control device according to the invention comprises a bridge circuit (6) for generating a rotating field for the motor (2) and a sensor system for detecting a position of a rotor of the motor (2), a control signal for the bridge circuit being derivable from the signal representing the rotor position. The sensor system comprises an absolute value transmitter (3) which detects the absolute position of the rotor and which is designed to derive at least one incremental signal (sH1, sH2, sH3) from the absolute position and to make it directly available to a control component (5) for controlling the bridge circuit (6) for commuting the motor (2).