Motor Control Device Phase Current Overshoot Suppression
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Solution Overview
Problem
Existing motor control devices using PWM control experience instability and overshoot in phase current after resuming, leading to motor torque vibration due to abrupt changes in phase current.
Innovation Solution
A motor control device with a control initiation-stop determiner and drive voltage controller that transitions the drive voltage state from stop to start, gradually increasing or decreasing phase current over time to minimize overshoot and stabilize torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If PWM control is resumed immediately when phase current falls below predetermined value, then control responsiveness is improved, but phase current overshoot occurs causing motor torque vibration
Solution Approach 1:
The control initiation-stop determiner determines whether to initiate control before the PWM control is actually resumed, preparing the control state in advance. When phase current falls below the predetermined value, the system determines control initiation in advance rather than immediately resuming, allowing for stable current increase without overshoot while maintaining quick response capability.
2Stability of the object's composition
If PWM control is stopped when phase current exceeds predetermined value, then motor torque vibration is suppressed, but control stability deteriorates
Solution Approach 1:
The control initiation-stop determiner determines control stoppage in advance based on phase current exceeding the predetermined value, rather than immediately stopping PWM control. This preliminary determination allows the system to prepare for control cessation, preventing abrupt current changes and torque vibration while maintaining overall control stability.
3Productivity
If phase current is allowed to change abruptly, then control efficiency is improved, but overshoot occurs causing device failure
Solution Approach 1:
The control initiation-stop determiner makes preliminary determinations about control state changes before they occur. By determining control initiation or stoppage in advance based on phase current conditions, the system avoids abrupt current changes that cause overshoot and potential device failure, while still maintaining efficient control operation.
Data Source
AI summary
The present invention includes: a control initiation-stop determiner which receives an initiation-stop request signal for controlling initiation and stop of a motor and information on the number of revolutions of the motor and which outputs a state signal for switching a state of a drive voltage among three states of control stop, control initiation, and control start; and a drive voltage controller which gradually increases a phase current supplied to the motor by using a PWM signal while the state signal causes the state of the drive voltage to transition from control stop to the control initiation and then to the control start.