Electric Motor Operating Point Control Under CPU and Memory Limits
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Solution Overview
Problem
Existing motor control systems fail to determine optimal operating points for electric motors across varying speeds, torques, voltages, and temperatures while adhering to CPU load and memory constraints, particularly in automotive applications where raw equations are computationally intensive.
Innovation Solution
A motor control system that includes a calibrator to modify inputs for the operating point controller, simplifying equations and allowing for efficient operating point determination by decomposing calculations, and a power stage control system to transform voltage requests into duty cycles, enabling optimized motor control without upgrading CPU resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If raw equations are used for determining operating points, then calculation accuracy is improved, but CPU load and memory usage increase excessively
Solution Approach 1:
The patent segments the operating point determination into two distinct modules: a calibrator module that performs preliminary calculations to generate modified speed values, and an operating point controller module that uses these modified values. This segmentation divides the computationally intensive raw equation calculations from the final operating point determination, allowing each module to be optimized independently for CPU efficiency while maintaining overall calculation accuracy.
Solution Approach 2:
The patent introduces modified speed values as an intermediary between the raw input parameters and the final operating point determination. These modified speed values act as a mediator that pre-processes the input data in a computationally efficient manner, reducing the complexity of subsequent calculations while preserving the essential information needed for accurate operating point determination.
2Productivity
If simplified equations are used for operating point determination, then CPU load is reduced, but operating point optimization is compromised
Solution Approach 1:
The patent transforms the input parameters by introducing modified speed values that are calculated using simplified relationships. This parameter transformation allows the operating point controller to work with pre-processed data that requires less computational effort, while the calibrator ensures that the transformation preserves the essential characteristics needed for accurate operating point determination across varying battery voltages.
Solution Approach 2:
The calibrator performs preliminary calculations to generate modified speed values before the operating point determination takes place. This preliminary action pre-processes the input data in a way that simplifies subsequent calculations, allowing the operating point controller to determine optimal points faster without sacrificing accuracy, as the heavy lifting has already been done in the calibration stage.
3Device complexity
If fixed battery voltage reference is used in operating point controller, then calculation simplicity is improved, but adaptability to varying battery conditions is reduced
Solution Approach 1:
The patent introduces dynamics into the system by having the calibrator continuously adjust the modified speed values based on the actual battery voltage. While the operating point controller uses a fixed reference voltage for simplicity, the calibrator dynamically compensates for battery voltage variations by modifying the speed input accordingly. This creates a dynamic adaptation mechanism that maintains accuracy across varying battery conditions without complicating the core control logic.
Solution Approach 2:
The calibrator serves as a self-adjusting component that automatically compensates for battery voltage variations without requiring the operating point controller to be reconfigured. The calibrator monitors the actual battery voltage and self-adjusts the modified speed values to maintain optimal operating point determination, enabling the system to adapt to varying battery conditions autonomously while keeping the main controller simple.
Data Source
AI summary
A motor control system determines an operating point for controlling an electric motor in an electric system that includes a battery and an electronic control unit. The motor control system includes a calibrator having an input for receiving a battery voltage of the battery, a motor speed, and a requested torque of the electric motor. The calibrator calculates a modified speed based on the received battery voltage, motor speed and requested torque. An operating point controller has an input for receiving a fixed battery voltage reference, the modified speed and the requested torque. The operating point controller determines the operating point for controlling the electric motor based on the received fixed battery voltage reference, the modified speed, and the requested torque.