Motor Control Apparatus Asynchronous Operation
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Solution Overview
Problem
Existing motor control systems with multiple microcomputers operating independently face challenges in maintaining continuous motor drive when one clock generation circuit fails, leading to potential motor drive stoppages and torque pulsations, especially in critical applications like electric power steering.
Innovation Solution
A motor control apparatus with multiple microcomputers and clock generation circuits, where each microcomputer and clock generation circuit is associated with a motor drive circuit, includes a synchronization signal generator and a timing corrector in the receiver microcomputer to determine synchronization signal normality, allowing for asynchronous operation if the signal is abnormal, ensuring continuous motor drive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple microcomputers operate with independently generated clocks to improve reliability, then system reliability improves, but motor drive synchronization deteriorates causing torque pulsations
Solution Approach 1:
A synchronization signal is introduced as an intermediary between the independently operating microcomputers. The synchronization signal generator produces a reference signal that is distributed to all microcomputers, serving as a common reference point. The timing corrector in each receiver microcomputer uses this intermediary signal to adjust its drive timing, thereby resolving the synchronization conflict while preserving independent clock operation for reliability.
Solution Approach 2:
The system dynamically changes the timing parameter of motor drive signals based on the received synchronization signal. Each receiver microcomputer adjusts its drive timing parameter by comparing its internally generated timing with the synchronization signal, and applies correction when necessary. This parameter adjustment resolves the synchronization issue while maintaining independent clock generation.
2Device complexity
If a single clock generation circuit is used to simplify the system, then device complexity reduces, but reliability deteriorates because motor drive stops when the clock generation circuit fails
Solution Approach 1:
The clock generation function is segmented and distributed to multiple independent microcomputers rather than using a single centralized clock generation circuit. Each microcomputer has its own independent clock generation capability, so that if one fails, others can continue operating. This segmentation resolves the contradiction by reducing the single point of failure while managing complexity through modular distribution.
Solution Approach 2:
The system prepares backup clock generation capabilities in advance by equipping multiple microcomputers with independent clock generation circuits. This beforehand cushioning ensures that if one clock generation circuit fails, other microcomputers can take over and maintain motor drive continuity, preventing system failure before it occurs.
3Manufacturing precision
If synchronization timing is strictly enforced to maintain motor drive precision, then manufacturing precision improves, but system adaptability deteriorates when synchronization signals become abnormal
Solution Approach 1:
The synchronization system is made dynamic by allowing microcomputers to switch between synchronized and asynchronous operation modes. When the synchronization signal is normal, the system operates in synchronized mode for high precision. When the synchronization signal becomes abnormal, the system dynamically adapts by allowing asynchronous operation, thereby maintaining both precision under normal conditions and adaptability under abnormal conditions.
Solution Approach 2:
The timing corrector implements feedback by continuously monitoring the synchronization signal and adjusting drive timing accordingly. When synchronization signals are received normally, timing corrections are applied to maintain precision. When synchronization signals become abnormal or are not received, the feedback mechanism detects this condition and allows the system to operate asynchronously, thus adapting to changing conditions while maintaining precision when possible.
Data Source
AI summary
A synchronization signal generating portion of a transmitter microcomputer generates a synchronization signal that is synchronized with a drive timing of the own microcomputer and also causes to synchronize the drive timing of microcomputers, and transmits to a receiver microcomputer. A timing corrector of the receiver microcomputer is capable of correcting the drive timing of the own microcomputer so as to synchronize with the received synchronization signal, and includes a timing determiner which determines whether the received synchronization signal is normal or abnormal. The receiver microcomputer permits the timing correction if the synchronization signal is determined to be normal in the timing determination, and prohibits timing correction and drives the motor asynchronously with the transmitter microcomputer if the synchronization signal is determined to be abnormal.