Resolver Angle Compensation for Stable PMSM Motor Control
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Solution Overview
Problem
In permanent magnet synchronous motors (PMSMs), particularly in eco-friendly vehicles, the time difference between the motor controller's control timing and the resolver's sensing timing leads to instability and torque ripple due to varying control periods and phase differences, affecting the accuracy of rotor position detection and motor control stability.
Innovation Solution
A motor control device and method that includes a resolver calculating the motor's angle of rotation based on voltage sensing values, and a motor controller extrapolating this angle using a time difference to align the control timing with the actual rotation, employing different PWM periods for resolver and motor control, and utilizing ATO logic for precise angle calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the motor controller and resolver operate with different PWM periods, then each can function independently according to their requirements, but a time difference occurs between control timing and sensing timing causing control instability and torque ripple
Solution Approach 1:
The patent introduces an angle compensation unit as an intermediary component that receives the resolver angle and timing information, calculates the timing difference, and generates a compensated angle. This compensated angle serves as a mediator that bridges the timing gap between the resolver's sensing operation and the motor controller's control operation, allowing both to maintain their independent PWM periods while achieving synchronized control效果
Solution Approach 2:
The angle compensation unit performs preliminary calculation of the timing difference and angle compensation before the motor controller executes the control action. By pre-calculating the compensated angle based on the known timing offset between sensing and control operations, the system prepares the corrected angle data in advance, ensuring that when the control signal is generated, it is based on the accurately compensated angle rather than the raw resolver angle
2Adaptability or versatility
If the control period of the motor controller varies, then the controller can adapt to different operating conditions, but the time difference fluctuates reducing control stability and increasing torque ripple
Solution Approach 1:
The angle compensation unit continuously receives timing information from both the resolver sensing operation and the motor controller operation, dynamically calculates the actual timing difference, and adjusts the angle compensation accordingly. This feedback mechanism ensures that even when the control period varies, the compensation remains accurate and up-to-date, maintaining control stability despite fluctuations in operating conditions
Solution Approach 2:
The angle compensation is not a fixed value but a dynamic calculation that adapts to changing operating conditions. The compensation unit continuously updates the compensated angle based on the current timing difference between sensing and control operations, allowing the system to maintain optimal performance across varying control periods and operating scenarios
3Productivity
If the resolver sensing timing does not align with the motor controller control timing, then the resolver can complete its sensing operation independently, but the detected angle differs from the actual angle at control timing affecting precision
Solution Approach 1:
The patent replaces the need for mechanical or temporal synchronization between the resolver sensing operation and motor controller operation with a computational angle compensation system. Instead of forcing the sensing and control operations to occur at the same time, the system uses mathematical calculation to compensate for the timing offset, substituting temporal alignment with computational correction to maintain angle detection accuracy
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances motor control stability and minimizes torque ripple by ensuring the detected angle of rotation at the control timing closely matches the actual angle, improving precision and efficiency.
Implementation Method 1
a resolver that calculates an angle of rotation of a motor in accordance with voltage sensing values from stator windings
Data Source
AI summary
Motor control devices and methods are described. According to one embodiment, a motor control device includes a resolver to calculates an angle of rotation of a motor in accordance with voltage sensing values from stator windings and a motor controller to calculate an angle of rotation for control by extrapolating the angle of rotation calculated by the resolver based on a time difference between a control timing and a voltage sensing timing of the resolver and to control the motor by using the angle of rotation for control.