Vehicle Motor Control Unit for Fast Torque Validation
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Solution Overview
Problem
Increasing number of control inputs and resultant latency affect the response time of motor control units (MCUs) in electric vehicles, impacting user experience and vehicle safety compliance with stringent functional safety requirements.
Innovation Solution
A motor control unit with three processors: a first processor to determine control outputs, a second processor to validate these outputs, and a third processor to monitor and control the system, including a dedicated communication bus for actuation demands, reducing latency and enabling fast torque reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of control inputs is increased to meet evolving vehicle technology requirements, then the control capability and safety coverage are improved, but the response time of the motor control unit deteriorates due to increased processing latency
Solution Approach 1:
The motor control unit is segmented into multiple specialized processors: a first processor for receiving control inputs and determining control outputs, a second processor for validating control outputs, and a third processor for monitoring system status. This segmentation allows parallel processing of different control tasks, reducing overall response time while maintaining comprehensive control capability across multiple input parameters
2Device complexity
If a single processor is used to handle all control inputs and outputs, then the device complexity is minimized, but the response time increases due to sequential processing bottlenecks
Solution Approach 1:
The control unit uses three specialized processors instead of a single processor, with each processor handling specific tasks in parallel. The first processor handles control input processing, the second handles validation, and the third handles monitoring and fault management. This segmentation reduces processing bottlenecks while maintaining manageable system complexity through clear functional separation
3Reliability
If comprehensive validation and monitoring are implemented to meet functional safety requirements, then the safety level is improved, but the processing time increases
Solution Approach 1:
The second processor performs validation of control outputs in parallel with the first processor's control determination, rather than sequentially after control determination. This preliminary action approach allows validation to occur concurrently, maintaining high safety levels through comprehensive checking while minimizing additional processing time penalties
Data Source
AI summary
A motor control unit for a vehicle comprising an electric drive motor, the motor control unit comprising a first processor, a second processor and a third processor, in which: the third processor is configured to: receive an actuation demand for the vehicle; calculate a torque for the motor in dependence on the actuation demand; and provide the calculated torque to the first processor; the first processor is configured to: receive the calculated torque and a control input of the vehicle; and determine a first control output for the electric drive motor in dependence on the calculated torque and the control input; and the second processor is configured to: receive the first control output from the first processor and the control input of the vehicle; calculate a second control output for the motor in dependence on the control input; and validate the first control output by comparison to the second control output.