Synchronous Motor Magnetic Pole Position Estimation via Induced Voltage
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Solution Overview
Problem
Conventional methods for estimating the magnetic pole position of a synchronous motor using induced voltage models are inefficient due to high computational requirements and precision errors, especially when transforming three-dimensional coordinates into two-dimensional rotational coordinates.
Innovation Solution
A method that calculates the induced voltage in a two-phase alternating current coordinates system with zero differential wave height, reducing computational complexity while maintaining precision by approximating the wave height as constant, thereby removing differential terms from the calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional dq rotational coordinates system transformation is used to estimate magnetic pole position, then position estimation can be performed, but computational complexity increases and precision errors occur
Solution Approach 1:
The patent extracts and removes the differential term from the induced voltage calculation, keeping only the algebraic terms. This simplifies the computational model while maintaining the essential relationship between voltage, current, and magnetic pole position, thereby reducing computational complexity without significantly compromising estimation precision
Solution Approach 2:
The patent changes the mathematical parameters of the induced voltage model by setting the differential of wave height to zero. This parameter transformation converts a complex differential equation into a simpler algebraic equation, reducing computational burden while preserving the core estimation functionality
2Productivity
If three-dimensional coordinates transformation is performed to obtain d-q components, then position estimation can be conducted, but error propagation occurs reducing precision
Solution Approach 1:
The patent extracts only the essential algebraic relationship between voltage and current components, eliminating the need for complex three-dimensional to two-dimensional coordinate transformation. By removing the transformation step and its associated error propagation, the method maintains estimation speed while improving precision
Solution Approach 2:
Instead of transforming detected three-phase currents into d-q components through coordinate transformation, the patent inverts the approach by directly utilizing the relationship between applied voltage and detected current in the simplified model, thereby avoiding error introduction from transformation
3Measurement precision
If extended induced voltage model with differential terms is used, then estimation precision can be maintained, but computational load becomes excessive
Solution Approach 1:
The patent extracts and retains only the essential algebraic terms from the extended induced voltage model, removing the computationally intensive differential terms. This selective extraction maintains the core estimation precision while dramatically reducing computational energy consumption
Solution Approach 2:
The patent applies parameter changes by setting the differential of wave height to zero, transforming the model from a differential equation requiring continuous computation to a static algebraic relationship, thereby reducing energy consumption while preserving estimation accuracy
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
This approach significantly reduces the computational load while maintaining high precision in estimating the magnetic pole position, improving stability and accuracy of motor control compared to traditional dq rotational coordinates systems.
Implementation Method 1
a magnetic pole position of a rotor in a synchronous motor is estimated from an induced voltage of the motor
Data Source
AI summary
In a method of estimating a magnetic pole position in a synchronous motor, an alternating current voltage having α- and β-axes components in an αβ coordinates system representing a two-phase alternating current coordinates system is applied to the motor, and α- and β-axes components of an alternating current are detected from the motor. A wave height of the alternating current changing with time is approximated to a wave height not depending on time, so that a differentiated value of the wave height with respect to time is substantially set at zero. An induced voltage of the motor is calculated from the components of the alternating current voltage and the components of the alternating current. The magnetic pole position is estimated from the induced voltage.