A black start controller based on a plurality of converter subarrays, wherein at least one of the plurality of converter subarrays (20_1) comprises at least one converter, an input port of each of the plurality of converter subarrays is connected to a direct current source (50_1), and an output port of each of the plurality of converter subarrays is connected to a first alternating current bus through a first transformer (40_2) and a control switch; and the black start controller is configured to: sequentially perform working processes of a first voltage adjustment phase to an N th voltage adjustment phase after controlling the control switch to be turned on and controlling a converter in each converter subarray to be powered on; and in an n th voltage adjustment phase of the first voltage adjustment phase to the N th voltage adjustment phase, synchronously send an n th target voltage adjustment instruction to each converter subarray, to control each converter in the converter subarray to establish an n th target alternating voltage, so that the n th target alternating voltage is converted by the first transformer into an n th target bus alternating voltage input to the first alternating current bus, wherein n and N are integers, and N is greater than 1, 1≤n≤N, the n th target alternating voltage is greater than an (n-1) th target alternating voltage, the n th target bus alternating voltage is greater than an (n-1) th target bus alternating voltage, and an N th target bus alternating voltage is a rated alternating voltage of the first alternating current bus, characterised in that the black start controller comprises a first controller and a plurality of second controllers (112_1), the first controller is communicatively connected to the plurality of second controllers, a converter in each converter subarray has a drive controller, the plurality of second controllers and the plurality of converter subarrays are disposed in a one-to-one correspondence, and each of the second controllers of the plurality of second controllers is communicatively connected to a drive controller in a converter in a corresponding converter subarray; the first controller is configured to synchronously send the n th target voltage adjustment instruction to each of the plurality of second controllers based on an n th piece of target alternating voltage data in a pre-established adjustment sequence in the n th voltage adjustment phase, wherein the adjustment sequence has a first piece of target alternating voltage data to an N th piece of target alternating voltage data that are sequentially arranged; any one of the plurality of second controllers is configured to send an n th voltage output instruction to a communicatively connected drive controller based on the received n th target voltage adjustment instruction; and the drive controller is configured to control, based on the received n th voltage output instruction, a corresponding converter to establish the n th target alternating voltage. the black start controller is configured to: sequentially perform working processes of a first voltage adjustment phase to an N th voltage adjustment phase after controlling the control switch to be turned on and controlling a converter in each converter subarray to be powered on; and in an n th voltage adjustment phase of the first voltage adjustment phase to the N th voltage adjustment phase, synchronously send an n th target voltage adjustment instruction to each converter subarray, to control each converter in the converter subarray to establish an n th target alternating voltage, so that the n th target alternating voltage is converted by the first transformer into an n th target bus alternating voltage input to the first alternating current bus, wherein n and N are integers, and N is greater than 1, 1≤n≤N, the n th target alternating voltage is greater than an (n-1) th target alternating voltage, the n th target bus alternating voltage is greater than an (n-1) th target bus alternating voltage, and an N th target bus alternating voltage is a rated alternating voltage of the first alternating current bus, characterised in that the black start controller comprises a first controller and a plurality of second controllers (112_1), the first controller is communicatively connected to the plurality of second controllers, a converter in each converter subarray has a drive controller, the plurality of second controllers and the plurality of converter subarrays are disposed in a one-to-one correspondence, and each of the second controllers of the plurality of second controllers is communicatively connected to a drive controller in a converter in a corresponding converter subarray; the first controller is configured to synchronously send the n th target voltage adjustment instruction to each of the plurality of second controllers based on an n th piece of target alternating voltage data in a pre-established adjustment sequence in the n th voltage adjustment phase, wherein the adjustment sequence has a first piece of target alternating voltage data to an N th piece of target alternating voltage data that are sequentially arranged; any one of the plurality of second controllers is configured to send an n th voltage output instruction to a communicatively connected drive controller based on the received n th target voltage adjustment instruction; and the drive controller is configured to control, based on the received n th voltage output instruction, a corresponding converter to establish the n th target alternating voltage.