Motor Control Device Using Inductance Ratio for Torque
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Solution Overview
Problem
Conventional motor control devices without rotor position sensors face challenges in adjusting operation parameters for maximum torque control and efficiency, requiring complex calculations and lengthy parameter adjustments, which complicates optimal motor operation and increases calculation loads.
Innovation Solution
A motor control device that estimates rotor position using a value between the real q-axis and d-axis inductances as an operation parameter, allowing for integrated adjustment of operation parameters and reducing the need for sequential calculations by maintaining the γ-axis component of the motor current at a predetermined value, facilitating maximum torque and efficiency control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional motor control devices use separate adjustment processes for operation parameters and maximum torque control parameters, then comprehensive control can be achieved, but the adjustment process becomes complex and time-consuming
Solution Approach 1:
The patent combines the operation parameter adjustment and maximum torque control parameter adjustment into a single integrated adjustment process. By setting the q-axis inductance value to a specific range (0.5 to 2.0 times the d-axis inductance), both control objectives are achieved simultaneously through one parameter setting, eliminating the need for separate complex adjustment processes.
Solution Approach 2:
The q-axis inductance parameter serves multiple functions: it acts as both the operation parameter for motor control and the maximum torque control parameter. This multi-functionality allows a single parameter adjustment to achieve both general motor operation and optimal torque characteristics, simplifying the overall control system.
2Productivity
If sequential calculations are performed for parameter adjustment and torque control, then precise control can be achieved, but calculation time and computational load increase
Solution Approach 1:
The patent performs preliminary action by pre-setting the q-axis inductance value within the optimal range (0.5 to 2.0 times d-axis inductance) during system design or initialization. This preliminary configuration ensures that both operation parameters and torque control parameters are optimally set from the start, eliminating the need for time-consuming sequential adjustments during operation.
Solution Approach 2:
By merging the two separate calculation processes into a single unified parameter setting, the patent reduces computational load and adjustment time. The unified approach calculates both operation and torque control parameters simultaneously through one set of calculations based on the inductance ratio, rather than performing sequential calculations.
3Reliability
If multiple operation parameters are adjusted separately for optimal performance, then motor efficiency can be optimized, but the adjustment process becomes lengthy and complicated
Solution Approach 1:
The q-axis inductance parameter is designed to serve universal purposes: it controls both the basic motor operation characteristics and the maximum torque performance. This universality means that adjusting this single parameter achieves both operational reliability and optimal torque control, eliminating the need for multiple separate parameter adjustments.
Solution Approach 2:
The patent utilizes parameter changes by specifically setting the q-axis inductance value within the range of 0.5 to 2.0 times the d-axis inductance. This parameter change approach allows the system to achieve optimal performance across different operating conditions by adjusting a single inductance ratio parameter, rather than modifying multiple independent parameters.
Data Source
AI summary
A motor control device includes an estimator for estimating a rotor position of a motor having a salient pole by using a value corresponding to a q-axis inductance of the motor as an operation parameter where an estimated axes for the control corresponding to d-q axes are γ-δ axes, and a controller for controlling the motor based on the estimated rotor position. The estimator generates a deviation between a d-axis and a γ-axis by performing the estimation of the rotor position based on a value between a real q-axis inductance and a real d-axis inductance of the motor adopted as the operation parameter. The controller controls the motor so that a γ-axis component of a motor current supplied to the motor is maintained to be a predetermined value of zero or close to zero regardless of a value of a δ-axis component of the motor current.