Power conversion system

A power conversion system (PCS) includes an alternating current (AC) power port, a first direct current (DC) power port, a second DC power port, a high voltage capacitor, a first DC converter, a second DC converter, a power inverter, and a microcontroller unit. The microcontroller unit adjusts a frequency of an AC power output by the power conversion system based on a voltage difference across the high voltage capacitor of the power conversion system to switch the frequency of the AC power between different frequencies.