Electric Machine Current Control via Compensation Filter
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current current control systems for electrical machines face challenges in achieving rapid and precise control due to voltage limitations and transient effects like eddy currents, leading to delayed responses and overshooting, especially when operating with high sampling rates and limited power supply voltages.
Innovation Solution
The method involves a compensation filter that simulates and inverts eddy current and displacement effects, allowing for pre-control signal adjustments to compensate for these transient issues, and an estimation device predicts actual current values to adjust pre-control signals accordingly, ensuring the current reaches the desired value without dropping off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If pre-control is used to increase control bandwidth and reduce adjustment time, then the control response speed is improved, but voltage limitations cause control signal restrictions that deteriorate control behavior
Solution Approach 1:
The patent applies preliminary action by using pre-control to calculate the required control signal in advance based on the setpoint and system model. This allows the control system to prepare the optimal control signal before execution, improving response speed while maintaining control quality through predictive calculation rather than reactive adjustment.
Solution Approach 2:
The patent combines pre-control with feedback mechanisms where the actual system response is continuously monitored and used to refine subsequent pre-control calculations. This closed-loop approach ensures that voltage limitations are accounted for in real-time, preventing control signal restrictions from deteriorating control behavior while maintaining high response speed.
2Measurement precision
If controller regulation is used to compensate for disturbance variables, then control accuracy is improved, but the integral calculation causes time delay in response
Solution Approach 1:
The patent eliminates the need for integral calculation by using pre-control to predict the required control signal in advance. This approach achieves control accuracy through model-based prediction rather than feedback integration, thereby eliminating the inherent time delay associated with integral calculations while maintaining the ability to compensate for disturbance variables.
Solution Approach 2:
The patent replaces the mechanical integral calculation process with a model-based predictive calculation. Instead of using feedback integration to determine control signals, the system uses a mathematical model to predict the optimal control action in advance, substituting the time-consuming integral operation with a faster computational approach that maintains accuracy.
3Measurement precision
If high sampling rates are used to improve control precision, then measurement accuracy is improved, but transient effects like eddy currents become visible and interfere with control
Solution Approach 1:
The patent converts the harmful transient effects into beneficial information by using them as indicators to adjust pre-control parameters. The visible transient effects at high sampling rates are not merely noise but provide valuable feedback about system dynamics, allowing the pre-control algorithm to optimize its parameters and actually improve control performance while maintaining high measurement accuracy.
Solution Approach 2:
The patent applies dynamics by making the pre-control parameters adaptive rather than fixed. The system dynamically adjusts pre-control parameters based on observed transient effects and system state, allowing the control strategy to evolve in real-time. This dynamic adaptation enables the system to maintain high sampling rates for measurement precision while using the observed transient effects to refine control actions and reduce their harmful impact.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The method receiving set value input (12) and nominal value (14) for current from the current regulator (10). The nominal value is generated by pilot control device (26) with respect to pilot signal (28,38). The inverse eddy current is simulated by filtering the pilot signal by a compensation filter (40). The current displacement effect of the electric motor (18) is provided to produce control signal for control value of electric machine at relay (16). Independent claims are included for the following: (1) current regulator device; and (2) computer program product for controlling current in electric machine.