Sensor-Free Rotor Position Detection Using Stator-Fixed Voltage Vectors
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Solution Overview
Problem
Existing sensor-free methods for armature position detection in electric machines are limited by requiring sinusoidal induced voltages and cannot operate independently of commutation types, restricting their applicability and noise response.
Innovation Solution
A method that determines the armature position by converting induced voltages into a stator-fixed Cartesian coordinate system, using a voltage vector, and applying a correction angle based on the voltage vector angle and rotation speed to accurately detect the armature position even with non-sinusoidal induced voltages, allowing for independent operation regardless of commutation type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the back-emf method is used for sensor-free position detection, then the armature position can be determined from induced voltage, but the method is restricted to sinusoidal induced voltage profiles and specific commutation types
Solution Approach 1:
The patent transforms the induced voltage measurements into a rotating reference frame (d-q coordinates) and applies parameter transformations to extract position information. By changing the mathematical representation from stationary to rotating coordinates, the method achieves universal applicability across different commutation types while maintaining precise position detection capability
Solution Approach 2:
The patent replaces the need for physical position sensors with an electronic calculation system that derives position information from voltage and current measurements through mathematical transformations. This substitution eliminates hardware limitations and enables flexible adaptation to various commutation strategies
2Loss of information
If phase connections are switched to deenergized state for measuring induced voltage, then position information can be obtained, but restrictions are placed on energization patterns and permanent voltage input is not possible
Solution Approach 1:
The patent introduces mathematical transformation models as intermediaries between the measured electrical quantities and the desired position information. Instead of directly measuring induced voltage during deenergized states, the system uses transformation equations to calculate position from continuously available voltage and current data, eliminating the need for measurement interruptions
Solution Approach 2:
The method enables continuous position detection by utilizing voltage and current measurements that are available throughout the entire commutation cycle. The mathematical transformations process data continuously without requiring interruption of the energization pattern, maintaining both measurement capability and operational flexibility
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
Enables precise and flexible sensor-free armature position detection suitable for polyphase electric machines with non-sinusoidal induced voltages, improving noise response and operational flexibility.
Implementation Method 1
ascertaining the induced voltages at the phase connections of the electric machine from the determined phase voltages and phase currents
Data Source
AI summary
The invention relates to a method for determining a rotor position of a rotatory, multi-phase, electronically commutated electric machine (1). Said electric machine (1) comprises several phase windings (4) which can be supplied with current by means of phase connectors. Said method consists of the following steps: phase currents and phase connections are identified on phase connections of the electric machine (1); the induced currents on the phase connections of the electric machine (1) are determined from the identified phase currents and phase flows; the identified current indicator of the induced current is provided with respect to a Cartesian coordination system which is fixed to a stator by the induced currents; the position of the rotor is identified as a space indicator angle of the current indicator of the induced current provided with respect to the Cartesian coordination system which is fixed to the stator.