Motor D-Axis Current Tuning for Maximum Torque Control
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Solution Overview
Problem
The existing methods for computing maximum torque in motors require complex equations that occupy significant program space and increase the load on microprocessors, making them inefficient.
Innovation Solution
A motor current optimization control method that step-wise adjusts the d-axis current command value and detects real-time feedback current values to determine the optimized d-axis current command value, reducing the program space and load on the microprocessor while maintaining maximum torque output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the conventional equation (1) with square root operation is used to compute maximum torque, then accurate maximum torque can be obtained, but program space is occupied and microprocessor load increases
Solution Approach 1:
The patent replaces the complex square root calculation with a simplified iterative approach using basic arithmetic operations. Instead of relying on heavy mathematical computations, the system uses a lookup table with pre-calculated values and simple iterative adjustments, effectively using 'cheap' computational methods instead of 'expensive' square root operations.
Solution Approach 2:
The patent transforms the problem from computing maximum torque directly using complex equations to finding optimal d-axis current by changing parameters iteratively. The system varies the d-axis current parameter step-by-step and selects the value that minimizes total current, avoiding the need for complex torque calculations while achieving the same optimization goal.
2Device complexity
If step-wise adjustment of d-axis current command value is performed to optimize current, then microprocessor load is reduced, but computation time increases
Solution Approach 1:
The patent performs preliminary calculations by pre-establishing a relationship between d-axis current and total current characteristics. The system uses pre-calculated lookup tables and established optimization curves that allow rapid determination of optimal current values without performing full iterative computations in real-time, thus reducing both microprocessor load and computation time.
Solution Approach 2:
The patent implements a dynamic optimization approach where the system adapts the d-axis current based on real-time operating conditions. The optimization process dynamically adjusts current values based on feedback, allowing the system to achieve optimal performance efficiently without fixed computational overhead, balancing speed and accuracy across different operating scenarios.
Data Source
AI summary
In a motor current optimization control method and system, while the motor runs steadily at a set speed, one d-axis current command value of the input current is set to 0. Then, the d-axis current command value is step-wisely increased by an increment at least twice. At least three real-time feedback current values can be collected from detecting a feedback current of an AC power. When an instant detected is smaller than the previous detected, the d-axis current command value is increased. When the instant detected is greater than the previous detected, the d-axis current command value corresponding to the previous detected is a minimum feedback current value and is defined as the optimized d-axis current command value. The optimized d-axis current command value is set as the d-axis current command value of the input current to control the motor to keep running steadily at the set speed.