Constant Current Precharging Algorithm for Solid State Power Controllers

Semiconductor-based solid-state power controllers (SSPCs) are a promising solution for dc system protection. During the connection of capacitive loads there is an inrush current because of zero initial energy in the capacitor, which can cause damage to the system. One of the main challenges of SSPCs is to suppress the current and voltage overshoot during precharging. In most of the precharging methods, additional circuitry is required, which adds weight, size, and complexity to the system. In this article, a constant current precharging algorithm is proposed. The main semiconductor device is utilized for precharging instead of adding an auxiliary circuit, thus reducing the required number of components. In addition, the proposed algorithm has a higher adaptability to the change of system parameters. Moreover, it is easily implementable to a wide range of semiconductor devices. Analytical evaluations are performed to compute the maximum current reference. Experimental results are presented to verify the operation under various operating conditions.