A modular power supply system is configured to include: a main controller, configured to output a main control signal; N local controllers, wherein each of the local controllers is configured to receive the main control signal to output at least one local control signal; N auxiliary power supplies, in one-to-one correspondence with the N local controllers, wherein each of the auxiliary power supplies is configured to provide power to the corresponding local controller, and N power units, in one-to-one correspondence with the N local controllers, wherein each of the power units includes a first end and a second end, the second end of each of the power units is connected to the first end of an adjacent one of the power units, each of the power units is configured to include M power converters, each of the power converters is configured to operate according to the local control signal.