Induction Motor Control via Non-Interference Flux Filtering
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Solution Overview
Problem
Existing induction motor control techniques fail to account for parameter changes and rotor magnetic flux delays, leading to unstable control responses due to parameter errors and transient response neglect.
Innovation Solution
The proposed control system uses a non-interference controller and a non-interference magnetic flux response filter to compensate for parameter changes and rotor magnetic flux delays, improving responsiveness by filtering interference voltages and simulating electric current delays, and allowing for variable parameters based on rotor characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional vector control is used without considering parameter changes, then the control structure is simple, but the control response becomes irregular due to parameter errors
Solution Approach 1:
The patent applies dynamics by making the self-inductance and mutual inductance parameters variable rather than fixed. The control device dynamically adjusts these parameters based on the operating point (torque and rotation speed) to match actual motor conditions, thereby maintaining reliable control response across varying operating conditions while keeping the overall control structure relatively simple.
Solution Approach 2:
The patent directly implements parameter changes by using operating-point-dependent self-inductance and mutual inductance values. Instead of using constant parameters, the system selects parameters that correspond to the current torque and rotation speed, which compensates for parameter errors and prevents irregular control responses without requiring complex adaptive algorithms.
2Speed
If control is performed neglecting rotor magnetic flux delay, then the control response is fast, but the control becomes unstable in practice
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the relationship between excitation current and rotor magnetic flux in a lookup table. This allows the control device to compensate for the inherent delay in rotor magnetic flux generation without requiring complex real-time calculations, maintaining fast control response while achieving stable control through advance preparation of flux information.
Solution Approach 2:
The patent introduces an intermediary mechanism by using a lookup table that stores pre-computed rotor magnetic flux values. This intermediary structure mediates between the excitation current input and the torque control output, allowing the system to account for flux delay effects without directly computing the delayed flux in real-time, thus maintaining both speed and stability.
3Adaptability or versatility
If non-interference controller computes interference voltage using mathematical model, then the control is independent, but parameter changes cause errors that are not accounted for
Solution Approach 1:
The patent resolves this contradiction by making the parameters in the non-interference controller adaptive to operating conditions. By using self-inductance and mutual inductance values that change with torque and rotation speed, the system maintains control independence through the non-interference structure while simultaneously accounting for parameter changes, thus preventing calculation errors and improving reliability.
Data Source
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AI summary
Disclosed is a three-phase AC induction motor control device for controlling a torque based on a two-axis orthogonal coordinate system in synchronization with a power supply angular frequency, the control device including: a non-interference controller configured to receive a motor rotation speed, a torque command value, and a power supply voltage as an input and compute a torque axis non-interference compensation voltage and a magnetic flux axis non-interference compensation voltage by referencing a map stored in advance; and a non-interference magnetic flux response filter configured to perform filtering, including a direct transfer term and a rotor magnetic flux response delay, for the torque axis non-interference compensation voltage.