Synchronous Motor Voltage Setpoints for Dynamic Torque Tracking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing control methods for externally excited synchronous motors (FESM) struggle with real-time torque control during dynamic changes, often leading to suboptimal solutions due to independent consideration of motor and excitation currents, reliance on offline data, and neglecting nonlinear couplings, which limits their effectiveness in dynamically changing conditions.
Innovation Solution
An operating method that accounts for temporal changes in target torque and actual currents to determine voltage setpoints, using current and voltage optimization problems to ensure the synchronous motor closely follows dynamic torque requirements while adhering to physical limitations, achieved through a setpoint determiner that calculates current and voltage setpoints in real-time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing control methods independently consider motor and excitation currents, then the control structure remains simple, but the torque control accuracy deteriorates during dynamic changes
Solution Approach 1:
The patent merges the independent control of motor current and excitation current into a unified optimization framework. The setpoint determiner simultaneously determines both current setpoints by solving a combined optimization problem that considers their nonlinear couplings, thereby improving torque control accuracy during dynamic changes while maintaining a manageable control structure through integrated decision-making.
Solution Approach 2:
The patent introduces dynamic adaptation by continuously solving optimization problems that account for temporal changes in target torque and actual currents. The control system dynamically adjusts current setpoints based on real-time operating conditions, enabling accurate torque tracking during transient states while adapting the control strategy to changing system requirements.
2Productivity
If offline data and pre-calculated values are used, then the computational load is reduced, but the response to dynamic torque changes becomes sluggish
Solution Approach 1:
The patent applies preliminary action by pre-defining the optimization framework, objective function, and constraint structures offline. These pre-configured elements enable rapid online computation where only the specific current values and torque targets need to be inserted, allowing fast response to dynamic changes without requiring full optimization model reconstruction during real-time operation.
Solution Approach 2:
The patent utilizes parameter changes by solving optimization problems with updated current values and torque targets at each control cycle. The optimization framework maintains fixed structural parameters (cost function coefficients, constraint matrices) while dynamically changing operational parameters (current magnitudes, torque references), enabling efficient real-time adaptation without full recomputation of the control architecture.
3Measurement precision
If linearized models are used for control, then the mathematical complexity is reduced, but the accuracy deteriorates due to neglected nonlinear couplings
Solution Approach 1:
The patent employs feedback by using actual current measurements and their temporal changes as inputs to the optimization problem. The controller continuously compares actual torque with target torque and adjusts current setpoints based on this feedback, while the optimization framework accounts for nonlinear couplings between motor and excitation currents, maintaining accuracy without requiring complex analytical solutions.
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 robust and efficient control of the synchronous motor by minimizing copper losses and ensuring the actual torque closely tracks the target torque, even under dynamic conditions, by directly determining voltage setpoints that consider both current setpoints and their changes over time.
Implementation Method 1
a separately excited synchronous motor (1) comprising a stator (2), a rotor (5), an excitation winding (6) and a motor winding (3)
Implementation Method 2
a converter unit (8), wherein the converter unit (8) is connected to the excitation winding (6) for applying an excitation voltage and supplying an excitation current and which is connected to the motor winding (3) for applying a motor voltage and supplying a motor current
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A separately excited synchronous motor (1) has a stator (2), a rotor (5), an excitation winding (6), and a motor winding (3). A setpoint detector (9) receives an instantaneous rotational speed (ω) of the rotor (5) relative to the stator (2), a target torque (M*) to be applied by the synchronous motor (1), a time-dependent change in the target torque (M*), and actual current values (lemax, Immax) for an excitation current (le) flowing in the excitation winding (6) and a motor current (Im) flowing in the motor winding (3).The setpoint determiner (9) determines voltage setpoints (Ue*, Um*) for an excitation voltage (Ue) driving the excitation current (le) and a motor voltage (Um) driving the motor current (Im) as a function of the rotational speed (ω), the setpoint torque (M*), the time change of the setpoint torque (M*) and the actual current values (lemax, Immax), so that the synchronous motor (1) provides an actual torque (M) corresponding to the setpoint torque (M*) as far as possible and the actual torque (M) changes as far as possible according to the time change of the setpoint torque (M*). The setpoint determiner (9) controls a converter unit (8) connected to the excitation winding (6) and the motor winding (3) according to the determined voltage setpoints (Ue*, Um*), so that the converter unit (8) applies voltages (Ue, Um) corresponding to the determined voltage setpoints (Ue*, Um*) to the excitation winding (6) and the motor winding (3).