Method to operate a system comprising an energy storage system in response to a bypass request based on a total number of modules to be bypassed

A system comprising:

• a converter having a first and second DC terminal, forming a DC side of the converter,
• an energy storage system (ESS) having at least one string of modules connected between the first and second DC terminal, the at least one string of modules comprising a plurality of modules, including at least one redundant module, and
• a central controller configured to control the system including
• receiving a bypass request to bypass at least one module in the ESS,
• based on a total number of modules to be bypassed exceeding a number of redundant modules in the ESS, controlling the converter to reduce the terminal voltage of the ESS, and
• after reducing the terminal voltage of the ESS, bypassing the module.

A method to operate a system comprising an energy storage system (ESS) and a converter, the ESS being connected to the converter such that a direct current (DC)-side of the converter forms DC terminals between which at least one string of modules of the ESS is connected, the ESS comprising a plurality of modules, including at least one redundant module, the method comprising:

• receiving a bypass request to bypass at least one module in the ESS;
• based on a total number of modules to be bypassed exceeding a number of redundant modules in the ESS, controlling the converter to reduce the terminal voltage of the ESS;
• and
• after reducing the terminal voltage of the ESS, bypassing the module,
• wherein the converter is controlled to reduce the terminal voltage until the string of modules has at least one redundant module.

A method to operate a system comprising an energy storage system (ESS) and a converter, the ESS being connected to the converter such that a direct current (DC)-side of the converter forms DC terminals between which at least one string of modules of the ESS is connected, the ESS comprising a plurality of modules, including at least one redundant module, the method comprising:

• receiving a bypass request to bypass at least one module in the ESS;
• based on a total number of modules to be bypassed exceeding a number of redundant modules in the ESS, controlling the converter to reduce the terminal voltage of the ESS, and after reducing the terminal voltage of the ESS, bypassing the module;
• and
• based on the total number of modules to be bypassed in the string exceeding the predetermined number of modules, tripping the ESS.

A method operate a system comprising an energy storage system (ESS) and a converter, the ESS being connected to the converter such that a direct current (DC)-side of the converter forms DC terminals between which at least one string of modules of the ESS is connected, the ESS comprising a plurality of modules, including at least one redundant module, the method comprising:

• receiving a bypass request to bypass at least one module in the ESS;
• based on a total number of modules to be bypassed exceeding a number of redundant modules in the ESS, controlling the converter to reduce the terminal voltage of the ESS;
• and
• after reducing the terminal voltage of the ESS, bypassing the module,
• wherein the ESS comprises a plurality of strings of modules connected in parallel to each other, and
• wherein the control of the converter to reduce the terminal voltage is based on a string with the lowest number of non-bypassed modules.