Synchronous Motor Torque Control via Phase-Adaptive Command Conversion
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Solution Overview
Problem
Conventional synchronous motor control systems impose limits on maximum torque to prevent control failures, restricting the motor's ability to utilize its full torque output.
Innovation Solution
A synchronous-motor control device that includes a torque-command-value conversion unit to convert the torque command into a second-torque command that gradually increases in the region including the peak torque, a voltage-phase control unit to control the voltage phase angle, and a power conversion unit to convert DC power into AC power based on the voltage phase angle and rotational angle, allowing the motor to output its maximum torque without limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a limit is imposed on the maximum torque of the motor to prevent control failures, then control reliability is improved, but the motor cannot sufficiently exert its inherent torque capability
Solution Approach 1:
The patent applies dynamics by making the torque command value adaptive rather than fixed. The torque command value is dynamically adjusted based on the relationship between voltage phase and torque characteristics, allowing the system to operate at maximum torque capability when conditions permit while maintaining stability. This resolves the contradiction by replacing static torque limiting with dynamic torque optimization.
Solution Approach 2:
The patent changes the parameter of torque command value from a fixed limited value to a variable that is optimally determined based on voltage phase characteristics. By calculating the torque command value according to the voltage phase-torque relationship, the system achieves both high torque output and control reliability, resolving the contradiction between torque capability and control stability.
2Power
If voltage phase control is used to increase motor output in high-speed rotation range, then power is improved, but control failures may occur due to torque deviation
Solution Approach 1:
The patent implements feedback by continuously determining the voltage phase and using it to calculate the optimal torque command value. This closed-loop approach ensures that torque commands are always aligned with actual motor characteristics, preventing torque deviation and control failures while maintaining high power output in the high-speed rotation range.
Solution Approach 2:
The patent applies preliminary action by pre-calculating the torque command value based on the voltage phase-torque relationship before actual torque application. This proactive determination of optimal torque commands prevents control issues from occurring, allowing the system to safely operate at maximum power output without risking control failures.
3Speed
If the torque command value is directly applied without conversion, then responsiveness is improved, but control failures occur due to excessive torque deviation
Solution Approach 1:
The patent applies preliminary action by pre-converting the torque command value through calculation based on voltage phase characteristics before it is applied to the motor. This preliminary conversion ensures that the torque command is optimally adjusted to match motor capabilities, achieving both rapid response and stable control without excessive torque deviation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the synchronous motor to utilize its full torque output without imposing limits, enhancing torque control and preventing control failures by smoothly matching the torque command with the motor's peak torque capability.
Implementation Method 1
a power conversion unit for converting DC power into AC power based on the voltage phase angle and a rotational angle of the synchronous motor, and for outputting the AC power resulted from the conversion to the synchronous motor
Data Source
AI summary
A synchronous-motor control device includes a torque-command-value conversion unit for converting a torque command value for a synchronous motor into a second-torque command value which gradually increases in a region including a peak of a torque of the synchronous motor, a voltage-phase control unit for controlling a voltage phase angle such that the torque of the synchronous motor matches the second-torque command value, and a power conversion unit for converting DC power into AC power based on the voltage phase angle and a rotational angle of the synchronous motor, and for outputting the AC power resulted from the conversion to the synchronous motor.