Electric control method and system for water surface power supply type underwater robot

The invention provides an electric control method for a water surface power supply type underwater robot. The electric control method comprises the following steps: a power supply step: transmitting alternating current to underwater through an umbilical cable; a power supply conversion step: converting the alternating current transmitted to the underwater into a direct current voltage, and supplying power to an ROV, a lower computer and a motor through the direct current voltage; and a signal access step: accessing a power line communication modem into the umbilical cable, and connecting an upper computer and the lower computer. According to the invention, the problem of insufficient endurance of a traditional battery-powered ROV is solved by adopting alternating-current input and cooperating with an alternating-current to direct-current power supply module, and the endurance without time limit is obtained; by the method of using the power line communication modem, the signal transmission can be performed thr