UPS inverter with integrated design of power circuits and controllers

This paper presents a method correlating the design of power circuits and controllers. The design of power circuits considers the voltage regulating performance as well as the attainable duty cycle of the inverter during the dynamic response. The voltage regulating performance make the design of power circuits have to consider many parameters that reveals the inherent capability of the inverter. The attainable duty cycle provides a way for evaluating the effectiveness of the controller related to the inherent capability of the inverter. A dual loops inductor current control technique is adopted as an example for the control of inverter in this paper. Through the introduction of a phase lead compensator in the current loop, the digital controller design can be simplified as an analog controller design such that the analysis is intuitive and the performance can be quantified easily. A multiple mode control technique is presented to enhance the performance of the voltage controller to achieve a more effective capability utilization of the inverter. The voltage THD (total harmonic distortion) at high crest factor (CK) load can be reduced significantly. A 2 kVA system is designed and implemented. The effectiveness of the proposed method is confirmed with some simulation and experimental results.