As the proportion of renewable energy increases, DC microgrids for power generation have become a research hotspot due to their advantages such as convenience and low loss. Given the stochastic and fluctuating nature of renewable energy sources, it is necessary to implement an appropriate control strategy on the converter, typically involving voltage source converters (VSCs), to achieve safe and stable operation of the system. In this paper, we examine a 100% renewable energy-based DC system employing grid-forming (GFM) and grid-following (GFL) controls and study the system’s various operating conditions and the active support capabilities of renewable energy in the event of system failures. The simulation results indicate that GFL can accurately control the power output of renewable energy sources but does not support the system, while GFM can stabilize the voltage, balance the power, and support the grid in the event of an accident. GFM control has great development prospects in the future.