Multi-converter Power Electronic Systems Research Articles

Analysis of Multi-Converter System’s Stability Using the Active Damping Method

In Multi-converter power electronic systems, load converters exhibit constant power load (CPL) behavior for the feeder converters and tend to destabilize the system. In this paper, Buck DC-DC converters are taken as an example, and the implementation of active-damping techniques has been shown to analyze the stability of multi-converter power electronic systems. Moreover, active damping is generally implemented by a feedback loop, which produces the effect of a virtual resistor and damps the oscillations, the proposed active-damping method can overcome the negative impedance instability problem caused by the CPLs. The effectiveness of the proposed approach has been verified by Matlab/Simulink simulations.

Discontinuous-Conduction Mode DC/DC Converters Feeding Constant-Power Loads

One of the major issues in multiconverter power-electronic systems, which exist in different land, sea, air, and space vehicles, is the stability problem imposed by constant-power loads (CPLs). The research work done in this field has been focused mainly on continuous-conduction mode of operation. In this paper, we study the case when the loaded converter operates in discontinuous-conduction mode (DCM). We prove that the open-loop DC/DC converters operating in DCM are stable when they are loaded by CPLs. Furthermore, we present that the problem of feedback design for a converter operating in DCM and loaded by a CPL can be translated into a conventional feedback-design task for the same converter with a resistive load. Simulation and experimental results verify the presented discussion.

Loop-Cancellation Technique: A Novel Nonlinear Feedback to Overcome the Destabilizing Effect of Constant-Power Loads

Tightly regulated closed-loop converters are problematic when used as a load since they tend to draw constant power and exhibit negative incremental resistance. This negative resistance causes stability problems for the feeder system, whether it is an input filter or another converter. In multiconverter power electronic systems, which exist in different land, sea, air, and space vehicles, including electric, hybrid, plug-in hybrid, and fuel-cell vehicles, there are many converters loaded by other converters. Therefore, the destabilizing effect of the load converters, which are called constant-power loads, is a major issue. In this paper, a novel nonlinear feedback, which is called loop cancellation, is introduced. This technique is used to cancel the destabilizing effect of the constant-power loads. Theoretically, any amount of constant-power load can be compensated by this technique, and it can identically be implemented on different types of converters. The effectiveness of the proposed technique has been verified by PSpice simulations and experimental results.

Active Damping in DC/DC Power Electronic Converters: A Novel Method to Overcome the Problems of Constant Power Loads

Multi-converter power electronic systems exist in land, sea, air, and space vehicles. In these systems, load converters exhibit constant power load (CPL) behavior for the feeder converters and tend to destabilize the system. In this paper, the implementation of novel active-damping techniques on dc/dc converters has been shown. Moreover, the proposed active-damping method is used to overcome the negative impedance instability problem caused by the CPLs. The effectiveness of the new proposed approach has been verified by PSpice simulations and experimental results.