Digital implementation of constant power load (CPL), active resistive load, constant current load and combinations

Abstract

Cascaded converters need to be tightly regulated to have better system performance and faster dynamic response. One of the major issues in cascaded converters is that they behaves as a constant power load (CPL) when tightly regulated. The current through a CPL decreases/increases with the increase/decrease of voltage across it, respectively. As a result, a CPL has negative incremental impedance, which causes a destabilizing effect. In order to study the converter's behavior with constant power load, a novel digital implementation of constant power load is proposed which emulates a DC/DC converter as a CPL. The digital implementation is controlled by a DSP which has the ability to be configured as a CPL, an active resistor load, constant current load or combinations. Further, the load can be dynamically changed.