PMSM Control via TRIAC Phase Cutting and Feedback
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Solution Overview
Problem
Existing control methods for permanent magnet synchronous motors in cost-sensitive applications, such as washing machines and dishwashers, fail to optimize energy usage and are prone to high operating noise and instability due to limited control electronics, which are not effective in responding to rapid load variations or preventing demagnetization.
Innovation Solution
A method and electronic device using a TRIAC switch controlled by a microprocessor for phase cutting of the electrical grid voltage, with feedback adjustments to optimize energy efficiency and reduce vibrations, employing either sensorless or sensored modes to manage the motor's starting and steady-state operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If simple control electronics are used to manage starting and stopping of the motor, then production and installation costs are reduced, but energy optimization is lost and operating noise increases
Solution Approach 1:
The patent implements feedback control by continuously monitoring the motor's operating conditions and adjusting the firing angle of the TRIAC switch accordingly. The microprocessor measures parameters such as counter electromotive force or load angle and modifies the switching timing to optimize energy efficiency while maintaining simple control electronics architecture
Solution Approach 2:
The patent changes the firing angle parameter of the TRIAC switch dynamically based on motor operating conditions. By adjusting this parameter, the system optimizes energy efficiency without requiring complex control electronics, resolving the contradiction between simplicity and energy optimization
2Ease of manufacture
If simple control electronics are used to manage starting and stopping of the motor, then production and installation costs are reduced, but operating noise due to vibrations increases
Solution Approach 1:
The feedback mechanism continuously monitors motor operation and adjusts the firing angle to maintain optimal operating conditions. This prevents excessive vibrations and noise while keeping the control electronics simple and cost-effective
Solution Approach 2:
The patent employs periodic switching of the TRIAC switch at optimized intervals determined by the firing angle. This periodic action synchronizes with the motor's operational cycle to minimize vibrations and noise while maintaining simple control architecture
3Ease of manufacture
If simple control electronics are used, then production cost is reduced, but stability of the motor deteriorates and response to rapid load variations is limited
Solution Approach 1:
The feedback control system continuously monitors motor stability and rapidly adjusts the firing angle in response to load variations. This maintains motor stability and responsiveness while keeping the control electronics simple and cost-effective
Solution Approach 2:
The patent implements dynamic adjustment of the firing angle based on real-time motor conditions. This dynamic control enables the motor to respond rapidly to load variations and maintain stability without requiring complex control electronics
4Ease of manufacture
If simple control electronics are used, then production cost is reduced, but demagnetization of the permanent magnet due to stator magnetic field occurs
Solution Approach 1:
The feedback control monitors motor operating conditions and adjusts the firing angle to prevent excessive stator magnetic field strength. This protects the permanent magnet from demagnetization while maintaining simple control electronics and low production cost
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
The solution achieves substantial energy optimization, improved motor stability, and reduced vibrations by fine-tuning the switching of the TRIAC switch based on counter electromotive force or load angle feedback, ensuring efficient operation across varying conditions without excessive cost or complexity.
Implementation Method 1
periodically switching on said switch in order to apply phase cutting to the voltage of the electrical grid
Implementation Method 2
synchronous electric motor with a permanent magnet rotor
Implementation Method 3
fine-tuning the switching of the TRIAC switch based on counter electromotive force or load angle feedback
Data Source
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AI summary
Method, which is efficient and cost-effective to implement, for controlling, at steady-state, a synchronous electric motor comprising a permanent magnet rotor and a stator provided with windings connected to an electrical grid (22) by means of a switch (21) controlled by a processing unit (30), said method comprising the following steps: - periodically switching on said switch (21) by means of a PWM output (33) of said processing unit (30); - continuously verifying the shift with respect to an ideal operating condition of the motor; - modifying the switched on period of the switch (21) in feedback to approach said ideal operating condition of the motor.