A novel control strategy for DC-DC converters driving constant power loads

Tightly regulated power electronic converters act as Constant Power Loads (CPLs) to the converters driving them. A CPL has a negative input impedance which results in a destabilising effect on the loaded DC-DC converters. This paper introduces a novel control strategy to stably control a DC-DC converter loaded by a CPL similar in concept to that of Sliding-Mode Control (SMC). The control strategy developed inherits the benefits of sliding mode control without the variable switching frequency, nor the need to measure any circuit currents. The new control strategy is easily implementable using analog circuitry or common Integrated Circuit (IC) technology. It is shown that all the benefits of SMC are also present using the novel control strategy when driving both resistive or constant current loads.