# Design and Experimental Validation of a Dynamic Frequency Sweeping Algorithm for Optimized Impedance Matching in Semiconductor RF Power Systems Under Pulse-Mode Operation

## TL;DR

This paper presents a dynamic frequency sweeping algorithm that improves impedance matching in RF power systems during pulse-mode operation, enhancing power transfer efficiency.

## Contribution

The novel algorithm dynamically adjusts frequency to optimize impedance matching in real-time under pulse-mode conditions.

## Key findings

- The algorithm achieves impedance matching and low reflected power within 5.0172 ms in experimental tests.
- It uses adaptive step size and predictive frequency initialization for efficient convergence.
- The method is validated on a 3 kW RF power source with 20 kHz pulse modulation.

## Abstract

The design and implementation of a dynamic frequency sweeping algorithm for a 3 kW RF power source are underpinned by theoretical principles aimed at optimizing impedance matching under pulse-mode operation. The algorithm dynamically adjusts the output frequency within a predefined range to align the source impedance Zsource with the conjugate of the load impedance Z*load, maximizing the power transfer efficiency and minimizing the reflection coefficient Γ. This is achieved by leveraging the maximum power transfer theorem and adapting to dynamic load variations, such as those induced by the plasma state transitions. The algorithm incorporates adaptive step size adjustments based on the rate of change of Γ, predictive frequency initialization using historical data, and real-time impedance monitoring to ensure efficient convergence within the constrained pulse “ON” time (TON). Integration with pulse mode requires synchronization with the pulse signal, fast convergence, and optimized search strategies. Experimental validation on a 13.56 MHz, 3 kW Automatic Sweep Generator testbed operating at 20 kHz pulse modulation with a 50% duty cycle demonstrates a linear and stable sweep, achieving impedance matching and low reflected power within 5.0172 ms. These findings highlight the algorithm’s potential for high-precision applications, such as RF plasma excitation, and underscore the importance of adaptive techniques in dynamic RF systems.