Using Input Invariance as a Method to Facilitate System Design in DPS Applications

Abstract

Distributed power supply (DPS) systems are extensively used to supply different electronic equipment and systems such as telecom switching systems. Continuous reduction of supply voltages of digital integrated circuits from the previous industry standard of 5 V down to 1 V or even less has necessitated the use of point-of-load system architectures due to high supply currents. The input currents of the switched-mode power supplies contain typically high ripple currents necessitating the use of noise suppression (EMI) filters to meet the stringent requirements stipulated by international standards. The interactions between the load converters, EMI filters, and supply side converters may adversely affect the stability and performance of the system. The system analysis is typically made based on the behavior of the ratio between the output impedance of the supply side and the input impedance of the load side known as minor-loop gain. Certain forbidden regions in the complex plane have been developed out of which the minor-loop gain should stay in order to guarantee stability. Even if the restrictions for the behavior of the minor-loop gain are well-defined, the accurate prediction of the associated impedances is difficult or even impossible. We propose, in this paper, a method based on input invariance to cancel the load-side interactions in the small-signal sense. The only concern left is then the stability of EMI filters, which may be considered based on the input power of the associated converters.

Stability and transient performance assessment in a COTS-module-based distributed DC/DC system

“…The module characterization already alluded to reduced interactions, which could be also deduced based on the datasheet information. As the origin of the interactions has been proved to be dependent on the topology as well as the applied control method and mode of operation, the data sheet information implies that the selected power modules are buckderived converters applying peak-current-mode control [20]. This control is proven to reduce the source-side interactions within the converter [21].…”

Introduction

“…The application of the remote sensing may profoundly change the dynamics of the associated converter depending on what kind of external passive circuit elements are connected inside the converter (Figure 1.6) as demonstrated in [46]. Therefore, the methods by means of which the interactions can be reduced or totally eliminated are of great importance and worth to be considered as explained and demonstrated in [47][48][49][50]. Therefore, the methods by means of which the interactions can be reduced or totally eliminated are of great importance and worth to be considered as explained and demonstrated in [47][48][49][50].…”

Average and Small‐Signal Modeling of Peak‐Current‐Mode Control

“…The input-to-output transfer function determines the level of the source interactions and the propagation of the load interactions through the converter [24][25][26]. Therefore, it may be obvious that the interactions taken place at the frequencies close to the resonant frequency would affect easily the VMC converter but not the PCMC converter.…”

“…25 The frequency responses of the input admittances of the VMC and the PCMC boost converters at the input voltages of 20 V (solid lines) and 50 V (dashed lines).…”