Switched Reluctance Motor Control Using Inactive-Phase Position Sensing
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Solution Overview
Problem
Existing switched reluctance motor drive systems face limitations in accurate rotor position estimation, especially at higher speeds, and require calibration for specific motor specifications and power ratings, which increases manufacturing complexity and resource usage.
Innovation Solution
A quasi-sensorless adaptive control method using a unique sequence of phase inductances to estimate rotor position, allowing for automatic calibration of the control algorithm to the inductance profile of each machine, eliminating the need for prior knowledge of motor specifications and enabling continuous speed monitoring with high resolution updates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If indirect rotor position sensing is used by monitoring terminal voltages and currents, then reliability is improved and size is reduced, but measurement precision deteriorates at higher speeds
Solution Approach 1:
The patent introduces an inactive phase as an intermediary element to sense rotor position. By applying voltage pulses to the inactive phase and measuring current response, the system obtains accurate position information without relying solely on active phase measurements, which become less accurate at higher speeds. This intermediary phase acts as a dedicated sensing channel that improves measurement precision while maintaining the sensorless approach's reliability and compactness.
2Manufacturing precision
If calibration is performed for specific motor specifications and power ratings, then manufacturing precision is improved, but device complexity and resource usage increase
Solution Approach 1:
The patent implements self-service through automatic calibration procedures that allow the control system to adapt to specific motor characteristics without external intervention. The system performs self-calibration by measuring inductance profiles and automatically adjusting control parameters, eliminating the need for manual calibration for each motor specification. This reduces device complexity and resource usage while maintaining manufacturing precision.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting control parameters based on measured inductance profiles. The system measures the actual inductance characteristics of the motor and modifies control parameters accordingly, allowing the same control algorithm to work across different motor specifications without requiring separate calibrated versions. This approach simplifies the manufacturing process while maintaining precision.
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 method enhances rotor position estimation accuracy, reduces the need for calibration, and simplifies manufacturing by automatically adapting to motor variations, providing a reliable, robust, and scalable solution for switched reluctance motor drives.
Implementation Method 1
A voltage pulse is applied to the inactive phase winding and current response in each inactive phase is measured
Implementation Method 2
establishing a firm time base for a software control module on a magnetic sensor
Data Source
AI summary
A method and apparatus for quasi-sensorless adaptive control of a high rotor pole switched-reluctance motor (HRSRM). The method comprises the steps of: applying a voltage pulse to an inactive phase winding and measuring current response in each inactive winding. Motor index pulses are used for speed calculation and to establish a time base. Slope of the current is continuously monitored which allows the shaft speed to be updated multiple times and to track any change in speed and fix the dwell angle based on the shaft speed. The apparatus for quasi-sensorless control of a high rotor pole switched-reluctance motor (HRSRM) comprises a switched-reluctance motor having a stator and a rotor, a three-phase inverter controlled by a processor connected to the switched-reluctance motor, a load and a converter.