Motor Control Device Preventing Step-Out via Current Component Analysis
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Solution Overview
Problem
Existing motor control methods, such as constant current control, often lead to motor step-out states due to excessive load torque, increasing power consumption and noise, and require costly vibration sensors for detection.
Innovation Solution
A motor control device with a detector, phase determiner, and controller that uses torque and excitation current components in a rotating coordinate system to adjust drive current, allowing for phase feedback control and switching between vector and constant current control modes to prevent step-out states without dedicated sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If constant current control is used to simplify motor control, then control complexity is reduced, but motor step-out occurs due to excessive load torque
Solution Approach 1:
The patent transforms the control approach by changing the parameter representation from stationary coordinate system to rotating coordinate system. By converting current values to torque current component (q-axis) and excitation current component (d-axis) based on rotation phase, the system achieves adaptive torque control without complex sensors. This parameter transformation enables the controller to adjust drive current according to actual torque requirements, preventing motor step-out while maintaining control simplicity.
2Measurement precision
If vibration sensor is added to detect motor step-out, then detection accuracy is improved, but device cost increases
Solution Approach 1:
The patent implements self-service detection by utilizing the motor control system's existing current detection capability to monitor its own operational state. The controller calculates torque current component and excitation current component from the drive current and rotation phase, then determines step-out condition by comparing excitation current component against threshold values. This self-diagnosis approach eliminates the need for external vibration sensors while maintaining accurate step-out detection.
Solution Approach 2:
The patent replaces the mechanical vibration sensing system with an electrical field-based detection method. Instead of using physical vibration sensors to detect mechanical anomalies, the system uses electrical current analysis in the rotating coordinate system to infer motor operational state. This substitution of detection principle eliminates hardware complexity while achieving the same diagnostic function.
3Reliability
If torque current component is increased to prevent motor step-out, then motor reliability is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic current control by continuously adjusting the torque current component (iq) and excitation current component (id) based on real-time rotation phase and load conditions. Rather than applying constant high current, the system dynamically optimizes current magnitude and phase angle, ensuring sufficient torque is provided only when needed. This dynamic adaptation prevents motor step-out while minimizing unnecessary power consumption during normal operation.
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
Enables efficient torque generation and accurate rotation phase control, reducing the likelihood of motor step-out states and power consumption, while providing an inexpensive configuration for abnormality detection.
Implementation Method 1
a motor (509) having a stator including a winding and a rotator (402) to be rotated by the winding
Data Source
AI summary
A motor control device includes a detector, a phase determiner, a controller, and an outputter. The detector detects a drive current. The phase determiner determines a rotation phase of a rotator based on the detected drive current. The controller is configured to perform control in a first mode for controlling the drive current based on a torque current component and in a second mode for controlling the drive current based on a current having a predetermined magnitude. The outputter outputs a signal indicating a value of the excitation current component of the drive current is equal to or smaller than a threshold value when the value of the detected drive current is equal to or smaller than the threshold value in a condition that the second mode is executed and a value corresponding to the rotating speed of the rotator is larger than a predetermined value.