Sensorless lc filter implementation for permanent magnet machine drive using observer-based voltage and current estimation
Journal
Sensors
Journal Volume
21
Journal Issue
11
Date Issued
2021
Author(s)
Abstract
For pulse width modulation (PWM) inverter drives, an LC filter can cascade to a permanent magnet (PM) machine at inverter output to reduce PWM-reflected current harmonics. Because the LC filter causes resonance, the filter output current and voltage are required for the sensorless field-oriented control (FOC) drive. However, existing sensors and inverters are typically integrated inside commercial closed-form drives; it is not possible for these drives to obtain additional filter output signals. To resolve this integration issue, this paper proposes a sensorless LC filter state estimation using only the drive inside current sensors. The design principle of the LC filter is first introduced to remove PWM current harmonics. A dual-observer is then proposed to estimate the filter output current and voltage for the sensorless FOC drive. Compared to conventional model-based estimation, the proposed dual-observer demonstrates robust estimation performance under parameter error. The capacitor parameter error shows a negligible influence on the proposed observer estimation. The filter inductance error only affects the capacitor current estimation at high speed. The performance of the sensorless FOC drive using the proposed dualobserver is comparable to the same drive using external sensors for filter voltage and current measurement. All experiments are verified by a PM machine with only 130 μH phase inductance. ? 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Subjects
Electric inverters; Electric machinery; Errors; Inductance; Parameter estimation; Permanent magnets; Pulse width modulation; Voltage control; Additional filters; Conventional modeling; Current estimation; Design Principles; Integration issues; Permanent-magnet machine; Pulse width modulation inverters; Sensorless field oriented control; Passive filters
SDGs
Type
journal article