Motor Control Circuit Mechanical Angle Reconstruction
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Solution Overview
Problem
Motor control circuits face issues with noise and oscillations in feedback signals due to unbalanced loads, leading to control problems when driving motors with eccentric loads.
Innovation Solution
A motor control circuit and method that determines the mechanical rotor angle by sampling electrical rotation signals at specific angles and generating a mechanical rotation signal, which is used to control motor performance parameters, thereby compensating for ripples and oscillations caused by unbalanced loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a motor control circuit uses closed loop control techniques to control motor speed and torque, then satisfactory control results are achieved for most applications, but when the motor drives an unbalanced load, vibrations cause noise and oscillations in the feedback signals leading to control problems
Solution Approach 1:
The patent converts the harmful vibrations from unbalanced loads into useful information by sampling the feedback signals at specific electrical rotation angles. The vibrations contain information about the mechanical rotor position that can be extracted through synchronized sampling and processing, transforming a detrimental effect into a beneficial source of position data for improved control stability
Solution Approach 2:
The system performs preliminary sampling of feedback signals at predetermined electrical rotation angles before the oscillations affect the control loop. By pre-synchronizing the sampling with the electrical rotation and storing samples in a buffer, the system captures the mechanical position information before it manifests as disruptive noise in the control feedback path
2Adaptability or versatility
If the motor is used to drive an unbalanced load, then the motor can perform the required work, but vibrations of the load cause oscillations in the speed control loop feedback signals
Solution Approach 1:
The patent segments the feedback signal processing by dividing the electrical rotation into discrete angular segments and sampling at specific angles within each segment. This segmentation allows the system to extract mechanical position information from specific portions of the feedback signal while filtering out oscillations from other portions, maintaining control stability when driving unbalanced loads
Solution Approach 2:
The patent introduces an intermediary processing stage between the motor feedback and the speed control loop. This intermediary samples the feedback signals, processes them through buffering and sorting algorithms, and generates a separate mechanical position signal that compensates for load-induced oscillations, allowing the motor to drive unbalanced loads without compromising control stability
Data Source
AI summary
A method of controlling a motor connected to an unbalanced load in accordance with an embodiment of the present application includes operating the motor for a predetermined period of time with a first performance parameter held constant, monitoring a signal related to a second performance parameter, monitoring electrical rotation within the motor and providing an electrical rotation signal indicative of the electrical rotation angle, sampling the signal related to the second performance parameter at a predetermined angle of electrical rotation, arranging samples provided in the sampling step in predetermined order and generating a mechanical rotation signal representing the mechanical rotation angle of a rotor of the motor based on the arrangement of samples. The mechanical rotation signal is used to control at least one of the first and second performance parameters of the motor.