Motor Drive Deceleration Control for Back-EMF Voltage Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing motor drive control methods face challenges in achieving rapid speed response during deceleration due to increased centrifugal force and counter electromotive forces, leading to unstable power supply voltage and potential component failure.
Innovation Solution
A motor drive control device that adjusts the operation amount change rate gradually, dividing it into multiple sections closer to the target rotation speed to stabilize power supply voltage during deceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the change rate of the operation amount is increased to improve speed response during deceleration, then the rotation speed reaches the target faster, but the power supply voltage increases due to counter electromotive force
Solution Approach 1:
The patent divides the operation amount change process into multiple sections with different change rates. When decelerating, the control device applies a first (larger) change rate initially, then switches to a second (smaller) change rate as the operation amount approaches the target, preventing excessive voltage spikes while maintaining responsive deceleration performance.
Solution Approach 2:
The patent dynamically adjusts the change rate of the operation amount based on the current state. The control device monitors the operation amount and automatically transitions between different change rates during deceleration, making the system adaptive to real-time conditions rather than using a fixed change rate.
2Loss of time
If the duty ratio is reduced rapidly to achieve faster deceleration, then the motor decelerates quicker, but counter electromotive force increases causing voltage instability
Solution Approach 1:
The patent segments the deceleration process into distinct phases with different duty ratio reduction rates. The control device applies a faster reduction rate initially to achieve quick deceleration, then transitions to a slower reduction rate near the target to prevent counter electromotive force-induced voltage instability, thus balancing speed and reliability.
Solution Approach 2:
The control device performs preliminary action by anticipating the voltage instability issue before it occurs. It proactively switches to a smaller change rate when the operation amount approaches the target during deceleration, preventing counter electromotive force buildup and voltage spikes before they can compromise system reliability.
3Speed
If a fixed large change rate is used for operation amount during deceleration, then speed response improves, but component reliability decreases due to voltage stress
Solution Approach 1:
The patent segments the deceleration control into multiple stages with different change rates. It uses a larger change rate in the initial stage to maintain fast speed response, then transitions to a smaller change rate in the final stage to reduce voltage stress on components, thus protecting component reliability while preserving overall speed performance.
Solution Approach 2:
The patent changes the parameter of change rate during the deceleration process. Instead of using a fixed large change rate, the control device dynamically adjusts the change rate parameter based on the current operation amount, reducing it when approaching the target to minimize voltage stress and protect component reliability.
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
Improves speed response and stabilizes power supply voltage during motor deceleration, preventing component failure and ensuring stable operation.
Implementation Method 1
a great counter electromotive force is generated at a coil of the motor due to a steep decrease in the operation amount of the motor, i.e., the duty ratio of the drive control signal at the time of deceleration
Data Source
AI summary
A motor drive control device includes a drive circuit for driving a motor based on a drive control signal, and a control circuit for calculating an operation amount of the motor so that the motor rotates at a target rotation speed based on a drive command signal specifying a target rotation speed and generates and outputs a drive control signal corresponding to the operation amount. The control circuit sets a change rate of an operation amount to be smaller the closer the operation amount to a target operation amount corresponding to the target rotation speed when decelerating the motor according to a change in the target rotation speed, and the control circuit changes the operation amount in accordance with the change rate so that the operation amount coincides with the target operation amount after change when decelerating the motor according to a change in the target rotation speed.