Because the scheme of energy storage unit inside the wind turbine has the advantages of flexibility and controllability

it is widely used in the field of fault ride through.However

the difference of energy storage unit is not considered in the previous analysis

which may cause power imbalance during the fault period and endanger the safe and stable operation of the system.To address this issue

a permanent DC fault ride-through coordinated control strategy based on precise control of wind farm energy storage is proposed.Firstly

the structure of the system

the energy storage control strategy

and the configuration of energy storage capacity are explained.Then

considering that one pole of the bipolar MMC-HVDC system still has the ability to operate normally when the other polar exits

the fault is divided into self-absorption and non-self-absorption cases according to the size of the unbalanced power.In the case of self-absorption

the unbalanced power is transferred to non-fault poles.In the case of non-self-absorption

the unbalanced power is precisely distributed to the internal energy storage units of the wind turbines based on the different State of Charge （SOC）levels.This ensures power balance in the system while reducing the differences between energy storage units.The capacity constraint of the energy storage units is addressed by the stepwise cut-off method

which ensures that the power balance is maintained when an internal energy storage unit is removed from operation.Finally

the effectiveness of the proposed fault ride-through scheme is verified through model simulation using the PSCAD/EMTDC platform.