Electric Power Steering Control Device Multiphase Winding Fault Detection
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Solution Overview
Problem
Conventional electric power steering control apparatuses experience delayed start-up due to sequential fault check processing on multiphase windings, leading to engine rotation malfunctions and prolonged processing times, especially in two-winding, three-phase motors with phase deviations.
Innovation Solution
An electric power steering control apparatus and method that includes a motor with multiphase windings and inverter circuits, utilizing relays to offset power supply timings and currents, allowing for individual initial checks and efficient drive control to initiate power steering control early.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fault determination processing is executed sequentially on all multiphase windings before starting power supply, then reliability of fault detection is improved, but loss of time occurs due to delayed start of power steering control
Solution Approach 1:
The control unit executes fault determination processing on a first multiphase winding before the second multiphase winding is activated. By performing preliminary fault checks on critical windings first and enabling power steering control based on those results, the system achieves early detection of faults without waiting for complete sequential processing of all windings, thus reducing overall processing time while maintaining reliability
Solution Approach 2:
The fault determination processing is divided into separate segments for different multiphase windings. The control unit processes the first winding independently and can initiate power steering control based on that segment's results, rather than requiring all segments to complete before starting operation. This segmentation allows parallel execution possibilities and reduces total processing time
2Productivity
If power is supplied simultaneously to all multiphase windings immediately after engine startup, then productivity of power steering control start-up is improved, but object-generated harmful factors occur due to engine rotation malfunction
Solution Approach 1:
The control unit performs preliminary fault determination processing on at least one multiphase winding before supplying power to all windings simultaneously. This preliminary check ensures that critical faults are detected in advance, allowing the system to safely enable simultaneous power supply to all windings without causing engine rotation malfunctions, thus achieving both fast start-up and operational safety
Solution Approach 2:
The control unit applies preliminary anti-action by detecting faults through fault determination processing before the harmful effect of simultaneous power supply can occur. By identifying potential issues in advance and taking preventive measures, the system prevents engine rotation malfunctions while still enabling rapid simultaneous power supply to all multiphase windings for immediate power steering control
Data Source
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AI summary
An initial check is executed individually on each group of a plurality of groups constituted by a plurality of multiphase windings (3a, 3b) of a motor (3) and a plurality of inverter circuits (9a, 9b) corresponding respectively thereto, opening/closing control is executed on a plurality of relays (6a, 6b) in accordance with an implementation result of the initial check so that respective timings at which power is supplied to the plurality of inverter circuits are offset, and drive control is executed on the plurality of inverter circuits in accordance with the implementation result of the initial check so that respective currents passed through the plurality of multiphase windings are offset.