I-f Control Method for SynRMs Uses Simple Inductance Identification and Voltage Injection for Current and Angle...

Area of Science:

• Electrical Engineering
• Motor Control Systems
• Power Electronics

Background:

• Sensorless vector control of synchronous reluctance motors (SynRMs) is effective at medium-to-high speeds.
• Extended back-electromotive force (EMF) or flux observation methods struggle in low-speed, low-current conditions where EMF and flux are near zero.
• Current frequency (I-f) control, common in permanent magnet synchronous motors (PMSMs), faces challenges when applied to SynRMs, particularly in controlling rotor angle and ensuring smooth sensorless transitions.

Purpose of the Study:

• To propose a novel four-stage I-f control method for SynRMs.
• To address the limitations of existing sensorless control methods in low-speed and low-current ranges.
• To enable smooth transitions to sensorless operation and improve motor performance.

Main Methods:

• A simple inductance identification method is employed to manage flux saturation in SynRMs.
• High-frequency voltage injection is utilized to continuously adjust current amplitude and rotor angle.
• The proposed I-f control method integrates inductance identification with high-frequency injection for robust control.

Main Results:

• The proposed four-stage I-f control method effectively manages SynRM operation across different speed ranges.
• Flux saturation is addressed through a simple inductance identification technique.
• Continuous adjustment of current amplitude and rotor angle ensures a smooth transition to sensorless control.

Conclusions:

• The developed four-stage I-f control method offers a viable solution for sensorless operation of SynRMs, especially in challenging low-speed regions.
• The integration of inductance identification and high-frequency voltage injection proves effective in overcoming SynRM control limitations.
• Experimental validation on a 5.5 kW SynRM confirms the method's effectiveness and practical applicability.