AC Motor Control Apparatus Phase Angle Optimization
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Solution Overview
Problem
Existing alternating-current motor control methods for maximum torque and efficiency face challenges in accurately determining the current phase angle and power loss variations, leading to suboptimal performance and inefficiency.
Innovation Solution
The proposed alternating-current motor control apparatus includes an inverter unit, current-command divider, current controller, torque-variation calculator, and phase angle generator, which divide command current amplitudes into d-axis and q-axis components based on phase-angle commands, calculate torque and power variations, and adjust phase angles to achieve maximum torque and minimum power loss, using search signals and filters to optimize motor control operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If direct calculations or parameter tables are used to determine current phase angle and current command components, then maximum torque can be obtained, but the control system becomes complex and sensitive to motor parameter variations
Solution Approach 1:
The patent employs feedback mechanisms where the actual motor current and voltage are measured, and the difference between actual and commanded values is used to adjust the phase angle dynamically. This feedback loop replaces complex open-loop calculations with adaptive closed-loop control, reducing sensitivity to parameter variations while maintaining torque optimization.
Solution Approach 2:
Instead of using fixed parameter tables or direct calculations based on motor parameters, the system dynamically adjusts the phase angle as a variable parameter based on real-time operating conditions. This transforms the control from a static parameter-based approach to a dynamic adaptive approach, simplifying the control structure while improving robustness.
2Power
If conventional current control methods are used to achieve maximum torque, then torque efficiency is improved, but power loss is not minimized and overall efficiency remains suboptimal
Solution Approach 1:
The patent introduces periodic alternating current signals to deliberately vary the phase angle around an operating point. By observing the resulting torque variations at different phase angles, the system identifies the optimal phase angle that simultaneously maximizes torque and minimizes power loss, rather than relying on conventional fixed-phase-angle control.
Solution Approach 2:
The control system automatically determines the optimal phase angle through self-testing with alternating current signals and observes the resulting torque variations. This self-adjusting mechanism eliminates the need for external parameter tables or complex calculations, allowing the system to autonomously optimize both torque efficiency and power loss minimization based on its own operational characteristics.
3Loss of energy
If the phase angle is adjusted to minimize power loss, then efficiency is improved, but torque output may be reduced without proper optimization
Solution Approach 1:
The patent applies the concept of vibration by introducing high-frequency alternating current signals to probe the system's torque response at different phase angles. This oscillatory approach allows the system to map out the torque-phase angle relationship dynamically and identify the optimal operating point where power loss is minimized without sacrificing torque output, effectively using controlled vibrations to find the global optimum.
Data Source
AI summary
An alternating-current motor control apparatus includes an inverter unit, a current-command divider, a current controller, a torque-variation calculator, and a phase angle generator. The current-command divider is configured to divide a command current amplitude into command current components based on a phase-angle command value that is a sum of the phase angle and an alternating current signal. The torque-variation calculator is configured to calculate a motor electric power based on the command voltage and either the motor current or the command current components and to calculate a torque variation based on the motor electric power. The phase angle generator is configured to generate a phase angle based on the torque variation.