Motor Winding Switching Circuit That Holds State During Resets
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Solution Overview
Problem
Conventional motor drive units fail to account for unexpected resets, such as those caused by lightning-induced noise or watchdog timer resets, leading to potential failures due to surge voltages and excessive counterelectromotive forces when switching winding configurations during high-speed operation.
Innovation Solution
A motor drive unit incorporating a winding configuration retention unit with an RS flip-flop and pull-up resistors to maintain the previous winding configuration state during resets, preventing unintended switching and ensuring reliable operation by decoupling the arithmetic processing unit's input-output ports from the winding switching instruction unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a microcomputer is used to generate winding switching instructions, then energy consumption efficiency is improved through optimal winding configuration selection, but reliability deteriorates due to unexpected resets causing unintended winding configuration changes and surge voltages
Solution Approach 1:
An RS flip-flop is introduced as an intermediary component between the microcomputer and the winding switching unit. The flip-flop receives the winding switching instruction signal and holds it stable even when the microcomputer undergoes a reset. This intermediary element decouples the microcomputer from direct control of the winding switching, preventing reset-induced unintended switching while maintaining the energy efficiency benefits of microcomputer-based control.
Solution Approach 2:
The RS flip-flop is configured with pull-up resistors to ensure that in the event of a microcomputer reset, the flip-flop maintains its previous state rather than transitioning to an undefined or harmful state. This beforehand cushioning prevents surge voltages and unintended winding configuration changes by preparing the circuit to withstand reset conditions before they occur.
2Ease of operation
If the arithmetic processing unit resets during operation, then all input-output ports transition to high impedance state, but this causes unintended winding configuration switching and surge voltage
Solution Approach 1:
The RS flip-flop serves as a mediator that isolates the winding switching unit from the high impedance state transitions of the microcomputer ports. By capturing the instruction signal before the reset takes effect, the flip-flop ensures continuous stable control signals to the winding switching unit, preventing surge voltage generation while allowing the microcomputer ports to naturally transition to high impedance during reset.
3Adaptability or versatility
If winding configuration switches during high speed rotation, then the motor adapts to different operational ranges, but excessive counterelectromotive force exceeds component withstand voltage
Solution Approach 1:
The RS flip-flop with pull-up resistors provides beforehand cushioning against unintended winding configuration changes during high-speed rotation. By maintaining the stability of the winding switching instruction signal even during microcomputer resets, the circuit prevents excessive counterelectromotive force generation that would otherwise exceed component withstand voltage limits.
Data Source
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AI summary
An electric motor drive unit (2) according to the present invention include a winding switching unit (7) that switches a configuration of windings of an electric motor, a winding switching instruction unit (12) that generates an instruction signal for the winding switching unit (7), and a winding configuration retention unit (13) to which the instruction signal generated by the winding switching instruction unit (12) is input, and if the input instruction signal has a first value, outputs a signal corresponding to the input instruction signal to the winding switching unit (7), and if the input instruction signal has a second value different from the first value, continues outputting a signal that has been output to the winding switching unit (7) before the reception of the second value, the first value indicating an instruction on the configuration of the windings.