Stepper Motor Out-of-Step Detection via Phase Current Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Stepper motors lack effective detection and prevention mechanisms for out-of-step conditions, particularly due to the reliance on mechanical encoders that increase costs and size, and fail to predict abnormal operations.
Innovation Solution
A motor state detection system using an electric circuit configuration that acquires current detection signals, processes them through low-pass filtering and masking units to generate output signals for judging normal, out-of-step entry, and out-of-step states, allowing for peak current adjustments and alarm outputs without additional mechanical devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an encoder is installed to verify motor operation, then motor position detection accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical encoder system with an electrical detection method. The motor state detector monitors the current detection signal from the motor phases and determines motor state (normal, out-of-step entry, out-of-step) by analyzing the duty ratio in the current chopping section, eliminating the need for mechanical position sensing components
Solution Approach 2:
The patent introduces a current detection signal as an intermediary to indirectly infer motor position and state information. By monitoring the electrical characteristics (current duty ratio) rather than directly measuring mechanical position, the system achieves detection functionality without mechanical encoders
2Measurement precision
If an encoder is installed to verify motor operation, then motor position detection is improved, but the size of the motor increases
Solution Approach 1:
The patent replaces the mechanical encoder system with an electrical detection method. The motor state detector monitors the current detection signal from the motor phases and determines motor state (normal, out-of-step entry, out-of-step) by analyzing the duty ratio in the current chopping section, eliminating the need for mechanical position sensing components
Solution Approach 2:
The patent extracts the detection functionality from the mechanical encoder system and implements it through electrical signal processing. By taking out the position detection function and realizing it through current signal analysis, the physical encoder components (rotating disc, light-emitting elements, light-receiving elements) are eliminated, reducing motor size
3Reliability
If traditional detection methods are used, then motor operation verification is possible, but out-of-step prediction and prevention capability is lost
Solution Approach 1:
The patent performs preliminary detection of out-of-step entry state by monitoring changes in the current detection signal duty ratio. When the duty ratio increases indicating out-of-step entry, the controller can take preliminary action by raising peak current before complete out-of-step occurs, enabling prediction and prevention of motor failure
Solution Approach 2:
The patent implements feedback control by continuously monitoring the current detection signal and comparing duty ratio characteristics against normal operation thresholds. The controller receives feedback about motor state (normal, out-of-step entry, out-of-step) and adjusts peak current accordingly, creating a closed-loop system that can predict and prevent out-of-step conditions
Data Source
AI summary
An image forming apparatus, a control method for the same, and a motor state detector are provided. An aspect is to detect out-of-step of a motor using only an electric circuit configuration without additional mechanical devices, such as an encoder, a light-emitting device, and a light-receiving device, and to predict and prevent out-of-step of the motor. To this end, the image forming apparatus includes a motor state detector that acquires a current detection signal by detecting phase current of a motor and that generates an output signal in which a duty ratio in a current chopping section of the current detection signal is involved, and a controller that judges a normal state, out-of-step entry, and an out-of-step state of the motor based on the output signal of the motor state detector.