Electric Motor Control Stabilization Filter Resonance
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Solution Overview
Problem
Existing control methods for AC electric motors, such as rectangular wave voltage control, suffer from degraded control responsiveness and stability due to resonance characteristics between input voltage and output current, leading to potential vibration and delayed control responses when motor rotation changes abruptly.
Innovation Solution
An electric motor control device that performs voltage phase control by adjusting the voltage phase command based on target torque, utilizing a d-q axis voltage generator and a stabilization filter to remove resonance characteristics and generate final voltage command values, thereby stabilizing the control system without degrading responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If voltage phase control is performed by controlling voltage phase depending on difference between torque command value and actual torque in rectangular wave voltage control, then output power in flux weakening area is improved, but control responsiveness is degraded
Solution Approach 1:
The patent introduces a voltage phase command value as an intermediary parameter that mediates between the torque command value and the actual torque. By controlling the voltage phase through this intermediate command value rather than directly responding to torque differences, the system achieves both improved output power in flux weakening area and maintained control responsiveness, resolving the technical contradiction.
2Stability of the object's composition
If control level of voltage phase is reduced to suppress vibration, then control stability is improved, but control responsiveness is degraded
Solution Approach 1:
The patent changes the parameter being controlled from the voltage phase itself to the voltage phase command value. By adjusting the voltage phase command value based on torque differences and applying it through the control system, the patent achieves vibration suppression and control stability improvement while maintaining fast response characteristics, thus resolving the contradiction between stability and responsiveness.
Data Source
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Figure 3A~3B
AI summary
An electric motor control device that performs a voltage phase control includes: a d-q axis voltage generator configured to calculate a d-q axis voltage command value based on the voltage phase command value and a voltage vector norm command value; a stabilization filter that includes first to fourth filters determined based on a transfer characteristic from an applied voltage to an output electric current and that is configured to remove resonance characteristics in the d-q axis electric current for the d-q axis voltage command value; and a voltage application unit configured to apply an AC voltage to the electric motor based on the final d-q-axis voltage command value. The stabilization filter is configured to generate the final d-axis voltage command value based on a result obtained by performing filtering by using the first and second filters for each of the d-axis voltage command value and the q-axis voltage command value and generate the final q-axis voltage command value based on a result obtained by performing filtering by using the third and fourth filters for each of the d-axis voltage command value and the q-axis voltage command value.