HRSRM Sensorless Control Using Self and Mutual Inductance
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Solution Overview
Problem
High rotor pole switched reluctance machines (HRSRMs) face challenges in accurate rotor position estimation due to a flatter self-inductance profile and neglect of mutual inductances, leading to unreliable position sensing without additional hardware or memory.
Innovation Solution
A sensorless control system utilizing a combination of self-inductance and mutual-inductance values, measured through terminal parameters like voltage and current, to estimate rotor position accurately without a rotor position sensor, using modules for self-inductance and mutual-inductance determination, storage, and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If self-inductance alone is used for position estimation in HRSRM, then the system is simpler, but position estimation accuracy deteriorates due to flatter inductance profile
Solution Approach 1:
The patent combines self-inductance and mutual inductance measurements to estimate rotor position. The controller measures both self-inductance (Laa) and mutual inductance (Lab) values and uses their combination to determine rotor position, thereby overcoming the limitation of using self-inductance alone which produces a flatter profile and less accurate position estimation in high rotor pole switched reluctance machines.
2Device complexity
If mutual inductance is neglected in position estimation, then calculation is simpler, but position estimation reliability deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the controller continuously measures self-inductance and mutual inductance values, processes these measurements to estimate rotor position, and uses this position information to control the switching of phase windings. This closed-loop feedback ensures reliable position estimation by incorporating mutual inductance measurements that provide additional information about rotor position.
3Measurement precision
If rotor position sensor is used, then position measurement is more accurate, but system cost and complexity increase
Solution Approach 1:
The patent enables the switched reluctance machine to determine its own rotor position using electrical measurements (self-inductance and mutual inductance) taken from its own phase windings. This self-service approach eliminates the need for external rotor position sensors, reducing system complexity and cost while providing sufficient position measurement accuracy for control purposes.
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
The system provides reliable, robust, and cost-effective rotor position estimation for HRSRMs, enhancing accuracy and eliminating the need for additional hardware, while being applicable across various motor speeds and directions.
Implementation Method 1
measuring a first current value through the at least one energized stator phase taken by the first current value to reach a first peak value of current... determining a self-inductance value for the at least one energized stator phase utilizing the first current value and time
Implementation Method 2
measuring a second current value through an adjacent un-energized stator phase... determining a mutual inductance value between the at least one energized stator phase and the adjacent un-energized stator phase
Data Source
AI summary
A system and method for reliable control of a high rotor pole switched reluctance machine (HRSRM) utilizing a sensorless reliable control system. The method comprising: energizing at least one of the plurality of stator phases; measuring a first current value and time taken by the first current value to reach a first peak value or preset threshold value of current; determining a self-inductance value; measuring a second current value and time taken by an adjacent un-energized stator phase to reach a second peak value of current; determining a mutual inductance value; and estimating a rotor position utilizing the self-inductance and mutual inductance values; and controlling the HRSRM based on the estimated rotor position.