Dual-Wound Synchronous Motor Current Decoupling Control
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Solution Overview
Problem
Conventional dual wound synchronous machines, such as dual wound permanent magnet synchronous machines (DW-PMSMs), do not effectively consider inductive coupling between the two sets of stator windings, leading to sub-optimal torque control performance due to the lack of analytical models capturing this effect, resulting in inefficient current and torque regulation.
Innovation Solution
The implementation of a system that determines virtual half-motor current commands and calculates corresponding voltage commands using specific gain factors to decouple the d-axis and q-axis components of the output currents between the two winding sets, allowing for independent control of each winding set through feedforward current controllers that account for electromagnetic coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional control algorithms are used that do not consider inductive coupling, then the control system is simpler to implement, but torque control performance is sub-optimal
Solution Approach 1:
The patent transforms the control parameters by introducing a coordinate transformation that converts the coupled dq-axis current equations into decoupled virtual half-motor current equations. This parameter transformation allows the control system to account for inductive coupling effects while maintaining implementation feasibility through modified feedforward voltage calculations.
Solution Approach 2:
The patent introduces virtual half-motor currents as intermediary variables that mediate between the actual coupled currents and the control inputs. These virtual currents serve as a mathematical transformation that eliminates the coupling terms, allowing independent control of each winding set while accurately representing the physical system.
2Device complexity
If feedforward current control without coupling consideration is used, then the control algorithm is less complex, but current and torque regulation efficiency is reduced
Solution Approach 1:
The patent modifies the control algorithm by changing the parameter representation from actual coupled currents to virtual decoupled currents through a mathematical transformation. This parameter change enables efficient regulation by eliminating coupling terms from the control equations while maintaining accuracy in representing the physical system behavior.
Solution Approach 2:
The patent segments the control problem by treating each winding set as an independent virtual half-motor. Through coordinate transformation, the coupled system is divided into two independent control channels, allowing separate optimization of each winding set's current and torque regulation without interference from the other set.
3Device complexity
If inductive coupling between winding sets is not accounted for, then the hardware topology and control structure remain conventional and simple, but overall system performance is sub-optimal
Solution Approach 1:
The patent applies parameter changes by transforming the system model to account for inductive coupling effects through a coordinate transformation. This transformation modifies the control parameters to include coupling compensation terms, enabling optimal performance while maintaining the conventional hardware topology and control structure.
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 enables optimal current and torque control performance by decoupling the d-axis and q-axis components of the output currents, enhancing the control flexibility and efficiency of dual wound synchronous machines.
Implementation Method 1
inherently have electromagnetic (inductive) coupling between the two sets of stator windings (i.e., coupling between electrical circuits due to induction caused by magnetic fields generated as a result of the currents flowing through each of the two sets of stator windings)
Data Source
AI summary
A method of controlling a dual-wound synchronous machine includes: determining positive and negative virtual half-motor current commands based on first and a second motor current commands associated with the first and second winding sets; calculating positive and negative final voltage commands based on the virtual half-motor current commands, and using first and second sets of gain factors; and commanding, based on the final voltage commands, inverters to apply an output voltage to each of two winding sets and thereby causing output currents to be generated herein. The output currents each have a d- and q-axis components, and at least one of the first set of gain factors and the second set of gain factors is configured to cause the d-axis component and the q-axis component of the first output current to be decoupled from variations of d-axis and q-axis components of the second output current.