Motor Control System Optimizing Field Torque Ratio
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Solution Overview
Problem
Existing drive control systems for motors face inefficiencies in generating torque due to eddy current losses and energy losses from armature and field coils, particularly when high torque is required, as they rely solely on controlling armature coil currents without optimizing field coil contributions.
Innovation Solution
A control system that calculates and adjusts the ratio of field torque to target torque, increasing the field torque contribution when high torque is needed, thereby reducing copper losses and overall energy consumption by optimizing current distribution between armature and field coils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If field coil is energized to generate field flux to assist base torque, then torque generation efficiency is improved, but copper losses increase due to additional current consumption in field coil
Solution Approach 1:
The control system dynamically adjusts the field torque ratio as a parameter based on the target torque magnitude. When target torque is high (≥ predetermined torque), the field torque ratio is increased to enhance torque generation efficiency. When target torque is low (< predetermined torque), the field torque ratio is decreased to minimize copper losses. This parameter change strategy optimizes the balance between productivity and energy loss.
2Adaptability or versatility
If current is supplied to both armature coil and field coil through different electric circuits, then torque control flexibility is improved, but device complexity increases due to separate control circuits
Solution Approach 1:
The control system merges the control of armature coil and field coil into a unified control framework. By calculating an optimal field torque ratio based on target torque and applying it to coordinate both coils' current supply, the system achieves flexible torque control while simplifying the overall control strategy. The separate electric circuits remain, but their control is integrated through the field torque ratio calculation.
3Loss of energy
If field torque ratio is increased to reduce energy losses at high torque demands, then overall energy efficiency is improved, but control complexity increases due to dynamic ratio adjustment
Solution Approach 1:
The field torque ratio is made dynamic rather than fixed, allowing the system to adapt to different operating conditions. The ratio changes based on the target torque magnitude: higher ratios are applied when target torque is high to reduce energy losses, while lower ratios are used when target torque is low. This dynamic adjustment optimizes energy efficiency across the entire operating range.
Solution Approach 2:
The control system performs preliminary calculation of the optimal field torque ratio before executing torque control. By pre-determining the appropriate ratio based on the target torque value and applying it subsequently, the system simplifies the control process and avoids complex real-time adjustments during operation.
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
This approach enhances torque generation efficiency by minimizing energy losses, particularly at high torque demands, and allows for improved energy efficiency and reduced copper losses, enabling the motor to operate along a constant output curve.
Implementation Method 1
an armature coil that is formed on the stator, and that is energized to create a rotating magnetic field with respect to the rotor
Implementation Method 2
a magnetic field generator having a field coil that is energized to generate a magnetic flux to enhance the magnetic flux created by the magnetic flux generator
Implementation Method 3
a torque of the rotor is controlled by controlling a base torque generated by energizing the armature coil, and a field torque generated by energizing the field coil
Data Source
AI summary
A control system for motor configured to control currents supplied to an armature coil and a field coil properly to achieve a required torque. The control system controls torque of a rotor by controlling a base torque generated by energizing an armature coil, and a field torque generated by energizing a field coil. When a target torque is equal to or greater than a predetermined torque, the controller controls the base torque and the field torque such that a ratio of the field torque to the target torque is increased greater than that of a case in which the target torque is less than the predetermined torque.