Sensorless Angular Speed Estimation Using Dimensionless Gain
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Solution Overview
Problem
Existing techniques for estimating the angular velocity of a permanent magnet machine are inadequate as they require the system to settle from a transient to a steady state phase before computation, which is problematic during modes like three-phase short operating modes, leading to delayed estimates.
Innovation Solution
A drive system with an electrical angular speed estimator module that computes estimated electrical angular speed using stationary reference frame feedback stator current samples and a dimensionless gain, allowing for estimation without waiting for the system to settle, specifically during three-phase short operating modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing estimation techniques are used, then the system can operate without sensors, but the computation is delayed until the system settles to steady state
Solution Approach 1:
The patent applies preliminary action by pre-processing stator current samples through a dimensionless gain filter before computation. This filtering operation is performed in advance to prepare the data for angular velocity estimation, enabling the system to compute estimates during transient phases rather than waiting for steady state settlement.
Solution Approach 2:
The patent changes the parameter representation by using dimensionless gain instead of traditional time-constant-based filtering. This parameter transformation allows the estimation algorithm to work effectively during transient conditions where traditional methods require steady state, thereby reducing computation delay while maintaining reliability.
2Measurement precision
If the system waits for steady state before computation, then estimation accuracy improves, but the response time decreases
Solution Approach 1:
By applying the dimensionless gain filter to stator current samples before estimation computation, the system prepares accurate data in advance. This preliminary filtering action maintains measurement precision while enabling computation to proceed during transient phases, thus improving response speed without sacrificing accuracy.
Solution Approach 2:
The patent replaces the traditional mechanical waiting period for steady state settlement with an electronic signal processing approach using dimensionless gain filtering. This substitution allows the system to achieve accurate estimates through computational methods rather than physical settling, thereby increasing estimation response speed while maintaining precision.
3Stability of the object's composition
If traditional estimation methods are used during three-phase short operating mode, then the system remains stable, but computation is delayed until transient phase ends
Solution Approach 1:
The patent changes the filtering parameter from time-constant-based to dimensionless gain-based representation. This parameter change enables the estimation algorithm to remain stable and accurate during three-phase short transient conditions, allowing computation to proceed without waiting for the transient phase to end, thus reducing computation delay while maintaining system stability.
Data Source
AI summary
Methods, systems and apparatus are provided for estimating electrical angular speed of a permanent magnet machine based on two-phase stationary reference frame feedback stator current samples, and a dimensionless gain (K) that is computed based on a sampling time (T) and machine parameters.