Adaptive control of power converters using Digital Network Analyzer Techniques

We describe a new method for design of adaptive controls for switching power converters that leverages the information-rich frequency response data obtained using the correlation-based analysis dubbed Digital Network Analyzer Technique. Compared to existing single-frequency based adaptive control methods such as limit-cycle and relay-feedback based autotuning, this method provides a unified approach to target many distinct problems plaguing converter control designers. The major strength of this method is that a single adaptive controller structure is able to fix multiple converter problems with a generalized and online identification and adaptation procedure. Also, unlike the conservative nature of robust control, adaptive control attempts to maintain relatively high performance at each time instant whenever possible. A step-by-step procedure is given which explains how the control platform can use the converter to perturb the system, identify the non-parametric frequency response of the plant, fit the data to a parametric model, and synthesize a control which meets user specifications. Simulation results are provided for a comprehensive set of realistic scenarios, where each test case uniquely degrades the converter frequency response. In each case, the performance and stability degradation is mitigated through targeted control adaptation.