Wound Field Motor Control Using Decoupled Rotating Reference Frames
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Solution Overview
Problem
Controlling wound field synchronous motors is challenging due to complex interactions between stator and rotor magnetic fields, leading to cross-coupling issues that complicate motor design and control, especially in high-performance applications.
Innovation Solution
The use of rotating reference frames with independent input channels, such as the MK and SM/DM transforms, decouples the intended output response in the stator D-axis component from the rotor field component, simplifying motor control by transforming motor information into frames like MK or SM/DM, which include axes that allow independent control of D-axis and rotor field components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional control methods are used for wound field synchronous motors, then the motor can operate, but cross-coupling between stator and rotor magnetic fields complicates control and reduces performance
Solution Approach 1:
The patent applies dynamic reference frame transformation (Park transform) to convert the stationary three-phase stator variables into a rotating reference frame that moves with the rotor. This dynamic transformation decouples the magnetic field interactions, allowing independent control of flux and torque components while maintaining synchronous operation. The rotating reference frame adapts continuously to rotor position, resolving the cross-coupling complexity.
Solution Approach 2:
The patent transforms the control parameters from the stationary ABC phase domain to the rotating dq reference frame domain. By changing the reference frame parameters dynamically based on rotor position, the complex coupled magnetic field equations are simplified into decoupled forms where d-axis controls flux and q-axis controls torque, significantly reducing control complexity.
2Productivity
If the motor operates at high performance levels, then productivity increases, but cross-coupling effects become more significant and difficult to control
Solution Approach 1:
The dynamic reference frame transformation continuously adapts to rotor position and speed, enabling high-performance operation by maintaining accurate decoupling even under varying load and speed conditions. The transforming coordinates dynamically with the rotor allows the control system to handle high-performance demands while managing cross-coupling effects through real-time parameter adjustment.
Solution Approach 2:
The patent employs feedback from rotor position sensors to continuously update the reference frame transformation. This feedback mechanism ensures that the decoupling remains accurate at high performance levels, allowing the controller to compensate for cross-coupling effects dynamically and maintain precise control even as productivity demands increase.
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 diagonalizes the motor system, reducing cross-coupling effects and simplifying control, enabling more accurate and efficient operation of wound field synchronous motors by decoupling the D-axis and rotor field components, thereby improving motor performance and design simplicity.
Implementation Method 1
the AC supply signals in stator windings of the stator generate magnetic fields that interact with a magnetic field or fields of the rotor to cause rotation of the rotor
Implementation Method 2
current is supplied to one or more field windings of the rotor to generate the magnetic field or fields of the rotor
Data Source
AI summary
Systems and methods are provided for controlling and simulating a motor. An electronic motor controller determines present motor information and a motor control parameter set based on the present motor information and a rotating reference frame of the motor. The rotating reference frame has independent input channels that decouple an intended output response in a stator D-axis component and a rotor field (R) component of a direct-quadrature-null-rotor (DQNR) reference frame. The electronic motor controller further controls the motor based on the motor control parameter set.