D'Q' Reference Frame for Independent Motor Torque and Flux Control
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Solution Overview
Problem
Existing electric motor control systems face challenges in efficiently controlling torque and flux independently, especially at high speeds and torque loads, where stator winding flux and motor voltage become excessive, leading to flux reduction needs.
Innovation Solution
The implementation of an enhanced vector control system that utilizes a D′Q′ rotating reference frame, allowing for independent control of torque and flux by adjusting the stator q′-axis and d′-axis currents, decoupling these controls and maintaining motor terminal voltage within limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If Field Oriented Vector (FOV) control is used to control torque and speed, then torque and speed control are achieved, but at high speeds and torque loads the stator winding flux and motor voltage become excessive
Solution Approach 1:
The patent changes the control parameters from the conventional DQ reference frame to a D′Q′ reference frame that is rotated by an angle φ. This parameter change allows independent control of torque (via q′-axis current) and flux (via d′-axis current), enabling the system to maintain motor terminal voltage within acceptable limits while avoiding excessive stator winding flux at high speeds and torque loads
2Adaptability or versatility
If conventional FOV control is used, then torque control is achieved through q-axis current, but independent flux control is not possible
Solution Approach 1:
The patent introduces a new reference frame parameter (D′Q′ rotated by angle φ) that enables decoupled control of torque and flux. The transformation equations convert between the conventional DQ frame and the new D′Q′ frame, providing independent control capability while maintaining compatibility with existing control structures
Solution Approach 2:
The patent adds a rotational dimension (angle φ) to the reference frame transformation, creating a new control dimension that enables independent flux control alongside torque control. This dimensional change allows the system to control both torque and flux independently without significantly increasing overall system complexity
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 effectively controls motor torque and flux, maintaining efficient operation across varying load conditions with reduced computational complexity and improved motor performance.
Implementation Method 1
the electric motor 14 draws a three-phase variable frequency alternating current which causes a portion of the electric motor 12 to rotate
Implementation Method 2
a first rotating reference frame having an axis aligned with a permanent magnet flux of a permanent magnet motor
Data Source
AI summary
A system. The system includes a first module, a second module communicably connected to the first module, a third module communicably connected to the first module, and a fourth module communicably connected to the third module. The first module is configured for determining an angle. The angle is defined by a first rotating reference frame having an axis aligned with a permanent magnet flux of a permanent magnet motor, and a vector of a motor magnetizing flux of the permanent magnet motor. The second module is configured for defining a second rotating reference frame having an axis aligned with the vector, and for transforming a two-phase set of direct currents from the first rotating reference frame to the second rotating reference frame. The first and second rotating reference frames are synchronized. The third module is configured for generating a first direct current reference signal associated with the second rotating reference frame. The fourth module is configured for generating a second direct current reference signal associated with the second rotating reference frame. The first and second desired direct current reference signals are orthogonal.