Electric Machine Drive Calibration With Pulsed Torque Control
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Solution Overview
Problem
Existing electric machines face inefficiencies due to varying operational loads, requiring manual calibration for dynamic motor drive (DMD) systems, which is labor-intensive and can lead to inaccurate torque measurements and increased power losses, especially in battery-powered applications.
Innovation Solution
Implementing a pulsed control methodology for electric machines that adjusts pulse width modulation and density based on torque output and efficiency considerations, combined with automatic calibration using in-situ sensors for NVH refinement and real-time monitoring to optimize DMD performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If manual calibration is performed for each vehicle model to reduce NVH, then NVH performance is improved, but labor time and calibration complexity increase significantly
Solution Approach 1:
The system performs automatic self-calibration by utilizing the electric machine itself as an excitation source to measure NVH frequency response and automatically adjust calibration parameters, eliminating the need for manual calibration of each vehicle model
Solution Approach 2:
A universal calibration method is implemented that can be applied across different vehicle models and manufacturers using the same automated process, making the calibration system multi-functional and model-agnostic
2Use of energy by moving object
If pulsed operation is used to improve energy conversion efficiency, then efficiency is improved, but torque measurement accuracy deteriorates due to inconsistent results from conventional filtering methods
Solution Approach 1:
The system applies normalization factors to torque measurements based on pre-determined relationships between pulsing duty cycle and torque output, correcting measurement inaccuracies before they propagate through the control system
Solution Approach 2:
The system continuously monitors torque measurements during pulsed operation and uses feedback control to adjust the normalization factors, ensuring accurate torque measurement while maintaining efficient pulsed operation
3Use of energy by moving object
If pulsed currents are applied to the battery to enable DMD operation, then electric machine efficiency is improved, but power losses increase due to higher resistive losses proportional to I2R
Solution Approach 1:
The system dynamically adjusts pulsed operation parameters including duty cycle, pulse frequency, and amplitude based on battery state (charge level, temperature, health) to minimize resistive losses while maintaining electric machine efficiency
Solution Approach 2:
The system transitions from static pulsed operation to dynamic pulsed operation where parameters are continuously adjusted based on real-time battery and motor conditions, optimizing the balance between motor efficiency and battery power loss
4Adaptability or versatility
If extensive pre-calibration is performed to cover all operating scenarios, then calibration completeness is improved, but system complexity and calibration time increase
Solution Approach 1:
The system performs periodic calibration updates during normal operation rather than requiring extensive pre-calibration, using periodic measurements to gradually build up calibration data across all operating scenarios
Solution Approach 2:
The system automatically performs calibration tasks during operation without requiring external calibration equipment or manual intervention, reducing system complexity while achieving comprehensive scenario coverage
Data Source
AI summary
Methods, systems, and devices for electric machine drive calibration, verification, and efficiency improvement are disclosed herein. One electric machine controller for calibration includes a processor and memory and instructions that are stored in the memory and executable by the processor to identify a vehicle and/or electric machine frequency response during operation of the vehicle and use the electronic machine and a dynamic motor drive converter to provide source excitations based on the identified frequency response.