Abstract : This paper introduces an automation system that uses one frequency converter to drive multiple electric submersible pumps (ESPs). Keywords : Frequency converter; PLC; Fieldbus; ESP; Synchronous switching 1 Introduction to the "One-Voltage-Multiple-Control" System In today's industrial production, frequency converters have been widely used. Offshore platforms utilize frequency converters to drive ESPs, changing the previous hard start ① vehicle-specific start ② to soft start ②, increasing the service life of ESPs, and enabling smooth start-up of ESPs even in some complex well conditions. It also offers advantages such as free control of ESP speed and energy saving. Therefore, we designed a "one-frequency converter-multiple-control" system specifically for the characteristics of ESPs used on offshore platforms. "One-frequency converter-multiple-control" refers to a system that, under certain special conditions (such as space constraints, funding constraints, etc.), uses only one (or a few) frequency converters and multiple PLCs to form a network control system to control the start and stop of multiple motors, provide motor protection, and automatically switch between frequency converters and mains frequency. Its advantages are small space occupation and relatively low investment; its disadvantage is that one ESP cannot exclusively use one frequency converter. Furthermore, because it needs to accommodate multiple electric pumps of different specifications, the inverter protection parameters are set relatively loosely, which can easily lead to situations where the motor cannot be protected. These situations must be resolved through other methods. We use a "one-to-many control" system on offshore platforms instead of a one-to-one inverter control system because the platform area is small, and the electric submersible pumps have relatively high power, resulting in a large inverter size that lacks installation space. Based on the site conditions, we selected inverters from Siemens (Germany) and a PLC system from Jinzhong Mole. 2. Basic Principles of "One-to-Many Control" The "variable" in "one-to-many control" refers to the inverter. It plays a very important role in the entire system. Therefore, the selection of the inverter directly affects the stability of the entire system. There are two better solutions: one is to directly use a high-voltage inverter; the other is to use a low-voltage inverter with a step-up transformer. Using a high-voltage inverter requires fewer devices, is simpler to use, and can easily achieve better control effects, but is expensive; a low-voltage inverter with a step-up transformer is cheaper, and if designed properly, can also achieve good control effects. After careful comparison... We selected two Siemens 6SE71 cabinet-type low-voltage frequency converters. [b][align=center]For details, please click: "One Converter, Multiple Controls" System for ESPs on Offshore Oil Platforms[/align][/b]