PM Motor Current Control Gain Adjustment via Frequency Characteristics
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Solution Overview
Problem
Conventional PM motor control devices face challenges in setting stable current control gains due to the need for pre-measurement of motor constants, which requires lengthy processes and may not maximize current response, especially when resistance and inductance are measured using different test signals.
Innovation Solution
A method that applies an applied voltage with a DC component and multiple frequency components to a PM motor, detects the motor current, and calculates a stable current control gain using frequency characteristics, allowing for quick adjustment of current control gains without the need for steady-state DC current measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If motor constants (resistance and inductance) are measured using conventional methods with different test signals, then measurement precision can be achieved, but the measurement process becomes time-consuming and complex
Solution Approach 1:
The patent combines resistance measurement and inductance measurement into a single AC voltage application process. By measuring both the in-phase component (related to resistance) and quadrature component (related to inductance) simultaneously from the same AC test signal, the method eliminates the need for separate DC and AC measurement steps, thereby reducing total measurement time while maintaining precision.
Solution Approach 2:
The patent performs preliminary identification of motor constants before actual motor operation. By pre-measuring resistance and inductance values using the optimized AC-based method, the system prepares control parameters in advance, avoiding time-consuming measurements during runtime and enabling faster system response.
2Speed
If current control gain is set high to maximize current response, then speed controllability improves, but system stability deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the measured motor constants (resistance and inductance) are used to dynamically calculate and adjust the current control gain. This feedback loop ensures that the gain is optimized based on actual motor characteristics, achieving high current response while maintaining system stability through adaptive tuning.
Solution Approach 2:
The patent changes the control gain parameter based on measured motor constants. By calculating the optimal gain value from the identified resistance and inductance values, the system adapts the control parameters to match the specific motor characteristics, thereby achieving both high response speed and stability.
3Stability of the object's composition
If current control gain is set too low to ensure stability, then system stability is maintained, but current response speed decreases
Solution Approach 1:
The patent dynamically adjusts the control gain parameter based on accurately measured motor constants. By using the identified resistance and inductance values to calculate the optimal gain, the system achieves the maximum stable gain value that provides both stability and high response speed, avoiding the conservative low-gain setting.
Solution Approach 2:
The patent replaces trial-and-error gain tuning with a calculation-based approach. Instead of mechanically adjusting gain values through experimentation, the system uses mathematical calculations based on measured motor constants to determine the optimal gain, achieving both stability and high response automatically.
4Measurement precision
If multiple separate measurements are performed to identify motor constants, then measurement accuracy improves, but device complexity and operation difficulty increase
Solution Approach 1:
The patent merges multiple measurement functions into a single AC voltage application step. By simultaneously measuring both the in-phase and quadrature components of the current response to an AC test signal, the system identifies both resistance and inductance in one operation, maintaining accuracy while simplifying the measurement process.
Solution Approach 2:
The patent creates a universal measurement method that uses a single AC test signal to perform multiple measurement functions (resistance measurement, inductance measurement, and time constant calculation). This multi-functional approach eliminates the need for separate DC and AC measurement procedures, making the operation simpler while maintaining comprehensive motor constant identification.
Data Source
AI summary
The present invention includes a voltage applying step of applying an applied voltage including a DC component and a plurality of frequency components to a PM motor, a motor current detecting step of detecting a motor current flowing depending on the applied voltage, and a current control gain adjusting step of calculating a current control gain based on frequency characteristics of the applied voltage and the motor current. In this manner, a stable current control gain having a high current response can be adjusted within a short period of time.