Dynamic Dead-Time Adjustment for Motor Torque Ripple Reduction
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Solution Overview
Problem
The existing motor control systems have a static non-changeable dead-time interval, leading to undesirable torque ripple in motors during certain commanded torque conditions.
Innovation Solution
A method and system that dynamically adjust the dead-time interval between de-activating a first transistor and activating a second transistor in a motor control circuit based on commanded torque values, using a handwheel torque sensor and controller to set and adjust the interval according to specific torque ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a static non-changeable dead-time interval is used in the motor control circuit, then the circuit structure is simple and easy to implement, but undesirable torque ripple occurs in the motor during certain commanded torque conditions
Solution Approach 1:
The patent applies the Dynamics principle by transitioning from a static dead-time interval to a dynamic dead-time interval that automatically adjusts based on commanded torque conditions. The control circuit continuously monitors the commanded torque and modifies the dead-time interval in real-time, allowing the system to adapt to varying operational requirements and eliminate torque ripple without requiring complex manual intervention or redesign.
2Object-generated harmful factors
If a dynamic dead-time interval adjustment is implemented to reduce torque ripple, then motor performance is improved, but the control circuit complexity increases
Solution Approach 1:
The patent applies the Parameter changes principle by modifying the dead-time interval parameter based on commanded torque conditions. The control circuit adjusts this single critical parameter dynamically, allowing torque ripple reduction while avoiding the need to redesign the entire control architecture. This focused parameter adjustment minimizes the increase in circuit complexity.
Solution Approach 2:
The patent implements a feedback mechanism where the control circuit continuously monitors commanded torque conditions and uses this information to adjust the dead-time interval. This closed-loop feedback approach allows the system to automatically compensate for torque ripple without requiring complex open-loop control schemes or multiple additional sensors.
3Object-generated harmful factors
If the dead-time interval is decreased for high torque conditions, then torque ripple is reduced, but the risk of transistor shoot-through increases if not properly managed
Solution Approach 1:
The patent applies the Dynamics principle by making the dead-time interval adaptive rather than fixed. The control circuit dynamically adjusts the dead-time based on real-time commanded torque conditions, automatically providing sufficient timing margin during high-torque transitions while allowing shorter intervals during low-torque operation. This dynamic adaptation maintains transistor protection across all operating conditions.
Solution Approach 2:
The patent applies the Local quality principle by applying different dead-time interval values to different torque conditions rather than using a single uniform value. The control circuit implements condition-specific timing parameters, providing enhanced protection during high-stress transitions while optimizing performance during normal operation. This localized adjustment of timing characteristics maintains reliability without sacrificing efficiency.
Data Source
AI summary
A system and a method for adjusting a dead-time interval between de-activating a first transistor and activating a second transistor in a motor control circuit are provided. The method includes determining a plurality of commanded torque values associated with a motor based on a received signal over time. The method further includes setting the dead-time interval value equal to a first value when one commanded torque value of the plurality of commanded torque values is within a first torque range. The method further includes decreasing the dead-time interval value as other commanded torque values of the plurality of commanded torque values increase over time within a second torque range. The second torque range is greater than the first torque range. The dead-time interval value is indicative of a desired dead-time interval.