AC Motor Control Device for Demagnetization Detection

The control device dynamically switches between the Vd-Vq estimation method and the Vq estimation method based on the detected output torque. When output torque is above a threshold, the Vq method is used; when below, the Vd-Vq method is used. This dynamic adaptation resolves the contradiction by selecting the appropriate estimation method for each operating condition, maintaining high measurement precision without requiring both methods to operate simultaneously, thus limiting device complexity increase.

The invention changes the estimation method parameter based on the operation state parameter (output torque). By detecting output torque and switching between estimation methods accordingly, the system adapts to varying operating conditions. This parameter-based switching resolves the contradiction by ensuring high estimation accuracy across different torque conditions while avoiding the complexity of implementing both methods continuously.

The system dynamically activates the Vd-Vq method only when output torque falls below the threshold, rather than operating continuously. This dynamic activation reduces the effective complexity by limiting the use of the more complex algorithm to specific operating conditions where it provides superior accuracy, while simpler methods handle normal operating conditions.

The invention changes the estimation approach based on the output torque parameter. When torque is low, the system switches to the Vd-Vq method which uses both d-axis and q-axis voltages for higher precision. When torque is high, it uses only the Vq method. This conditional parameter-based switching resolves the contradiction by applying complexity only when measurement precision requirements demand it.

The control device automatically and dynamically switches between estimation methods based on detected output torque, without requiring manual intervention or complex configuration. This automatic dynamic switching maintains ease of operation while improving reliability by ensuring the appropriate estimation method is used for each operating condition, preventing incorrect demagnetization detection.

The system uses feedback from output torque detection to automatically select the appropriate magnetic flux estimation method. The torque detector provides feedback that triggers method switching, creating a closed-loop control system. This feedback mechanism resolves the contradiction by automatically adapting to operating conditions without user intervention, maintaining simplicity while ensuring reliable demagnetization detection across all torque levels.