Electric Machine Control via Fault State Operating Point Shift
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Solution Overview
Problem
Faults in the power electronics of converter-fed electrical machines limit their operational capability, as they struggle to implement electrical voltage vectors effectively due to semiconductor or control electronics failures, leading to reduced torque generation and potential loss of normal operation modes.
Innovation Solution
A device and method that determine a fault state operating point based on a target torque value, error signals, and current rotor angle, allowing the control system to shift the operating point from a normal state to a fault state along a specific trajectory, thereby compensating for errors and maintaining torque generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If power electronics are used to control electrical machine torque, then torque generation capability is improved, but system reliability deteriorates due to semiconductor or control electronics failures
Solution Approach 1:
The control device is designed to detect power electronics failures and calculate alternative operating points before the system completely fails. By preparing compensation strategies in advance through the operating point calculator, the system maintains torque generation capability even when power electronics malfunction, thus resolving the contradiction between improved power control and reduced reliability
Solution Approach 2:
The invention converts the harmful effect of power electronics failures into a beneficial outcome by using the operating point calculator to determine alternative operating points that compensate for the failures. This allows the system to maintain or even improve torque generation despite the presence of faults, effectively turning the reliability problem into an opportunity for enhanced robustness
2Power
If operating point is shifted to compensate for power electronics errors, then torque generation is maintained, but device complexity increases
Solution Approach 1:
The control device performs multiple functions: it detects power electronics failures, calculates alternative operating points, and executes compensation control. By integrating these functions into a single multi-functional control unit, the patent avoids the need for separate dedicated systems for each function, thus maintaining torque generation while limiting the increase in device complexity
Solution Approach 2:
The operating point calculator automatically detects failures and computes compensation operating points without external intervention. The control device self-adjusts by shifting to alternative operating points, eliminating the need for complex external monitoring and adjustment systems, thereby maintaining torque generation with minimal added complexity
3Adaptability or versatility
If fault state operating point trajectory is implemented, then operational range is expanded, but control precision requirements increase
Solution Approach 1:
The invention implements dynamic adaptation by continuously calculating and shifting to alternative operating points based on real-time failure detection. The operating point trajectory is dynamically adjusted according to the specific failure mode and system state, allowing the electrical machine to operate across an expanded range while managing control precision requirements through adaptive rather than static control
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
The invention provides a device (10) and a method for controlling an electric machine (1). The method comprises the steps of: providing (S01) a desired torque value (54) for a torque to be exerted by the electric machine (1); determining (S02) a fault signal (51) which indicates a fault state of the electric machine (1); determining (S03) a current rotor angle value (56) of the electric machine (1); determining (S04) a fault state operating point (62; 62') on the basis of the desired torque value (54) provided, the determined fault signal (51) and the determined current rotor angle value (56); and shifting or moving (S05) an operating point, at which the electric machine (1) is operated, from a normal state operating point (61) to the determined fault state operating point (62; 62').