Grid voltage sensorless control of a single-phase shunt hybrid active power filter

Here, a grid voltage sensorless control of an LCL-filtered LC-tuned single-phase shunt hybrid active power filter (HAPF) is proposed, which offers high-quality harmonic current compensation with low hardware requirements. An estimation algorithm replaces the grid voltage sensor and associated circuitry to reduce the size and cost. This paper presents a straightforward and accurate modelling of the suggested structure and its filtering characteristics, followed by a comprehensive yet simple parameter design procedure. An inherent damping technique that uses digital delay rather than virtual or physical damping resistors eliminates the need for additional sensors or extra power losses. As part of the design, a high-quality reference current is generated for the filter, which is then effectively tracked using a proportional controller with sufficient bandwidth and stability margin. An experimental prototype is implemented to verify the theoretical results, and several steady-state and transient waveforms are reported to demonstrate the superior performance of the HAPF.