Sensorless Synchronous Motor Controller Using Frequency Deviation Analysis
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Solution Overview
Problem
Single-phase synchronous motors require sensors to prevent falling out of synchronization under excessive torque, which is economically and technically inconvenient.
Innovation Solution
A permanent magnet synchronous machine with a motor controller that detects terminal current and frequency components, adapting the terminal voltage's amplitude and frequency to maintain synchronization without additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sensors are installed to detect rotor position and prevent falling out of synchronization, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent extracts the position detection function from physical sensors and implements it through sensorless observation of current frequency characteristics. The rotor position information is obtained by analyzing the frequency components of the terminal current, eliminating the need for additional sensors while maintaining synchronization detection capability.
Solution Approach 2:
The patent replaces the mechanical/electrical sensor system with an analytical approach based on electrical signal processing. By monitoring the frequency of terminal current and detecting deviations from supply frequency, the system substitutes physical measurement with electrical characteristic analysis, reducing device complexity.
2Reliability
If terminal voltage amplitude and frequency are continuously adapted to maintain synchronization, then reliability is improved, but use of energy increases
Solution Approach 1:
The patent implements a feedback mechanism where the terminal current frequency is continuously monitored and compared with the supply frequency. When a frequency deviation is detected indicating synchronization loss, the controller adjusts the terminal voltage amplitude and frequency accordingly, creating a closed-loop control system that maintains synchronization efficiently.
Solution Approach 2:
The patent applies partial action by only adapting the terminal voltage when necessary - specifically when frequency deviation exceeding a threshold is detected. Rather than continuous adjustment, the system intervenes selectively to correct synchronization issues, reducing unnecessary energy consumption while maintaining reliability.
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 sensor-free control, maintaining rotor synchronization by monitoring and adapting voltage frequency and amplitude in response to frequency deviations, ensuring continuous operation without sensor installation.
Implementation Method 1
an analysis device (12) for ascertaining whether the current frequency (fa) contains a frequency component (fr) with a frequency that deviates from the feed frequency (f0)
Implementation Method 2
a rotor (R) and a stator (S) formed with connection terminals (2) to apply a feed alternating voltage with a feed frequency (f0)
Data Source
AI summary
A permanent magnet synchronous machine (1) having a rotor (R) and a stator (S). Connection terminals (2) apply a feed alternating voltage with a feed frequency (f0). The permanent magnet synchronous machine (1) has a motor controller (10). The controller (10) has an assembly (11) to detect the terminal voltage on the connection terminals (2) and the current frequency (fa). Also, the controller has an analysis device (12). The analysis device (12) ascertains whether the current frequency (fa) contains a frequency component (fr) with a frequency that deviates from the feed frequency (f0).