How does the three-phase charging pile motherboard balance the load?

There are several methods for designing a three-phase charging station motherboard to balance the load, including:

Real time monitoring and dynamic adjustment

• Real time monitoring of current: Real time monitoring of the three-phase current of the charging pile group, based on the specific numerical changes of each phase current, identifying whether the pile group needs balance control or rapid adjustment, and generating control signals or rapid adjustment signals based on the identification results.

• Dynamic adjustment of current: Adjust the current value associated with each phase of the pile group based on the control signal. When the current demand at the next moment is different from the previous moment, current control is carried out according to a certain control process, prioritizing the current output control of the phases associated with the corresponding positions in the sorting calibration sequence, so that the currents of each phase gradually converge and complete the balance control process.

Commutation control

• Detecting current differences: Determine the phase, second phase, and third phase of the three-phase AC power based on the magnitude of the current in each phase. When the difference between the current in the phase and the current in the second phase exceeds a preset threshold, generate commutation control commands.

• Perform commutation operation: After receiving the charging command, the main board of the three-phase charging pile to be charged controls the commutation of the three-phase charging pile to the third phase according to the commutation control command, so that the input terminal of the phase is connected to the output terminal of the third phase, and the input terminal of the third phase is connected to the output terminal of the phase, thereby achieving the balance of the three-phase load.

Current balancing technology

• Utilizing inductance and capacitance compensation: using inductance and capacitor banks to achieve different phase to phase current transfer. If the current in phase A is too high and the current in phases B and C is too low, then a capacitor is connected in parallel in phases A and B, and an inductor is connected in parallel in phases A and C. Through the phase shifting and compensation effects of the inductor and capacitor, the current in phase A is transferred to phases B and C to achieve three-phase balance.

• Control switching operation: Real time switching of capacitors and inductors can be controlled according to actual load changes to ensure three-phase load balance at any time.

Optimize charging strategy

• Reasonably allocate charging power: In the design process of the charging station, three charging piles are used as a load unit, powered by a cable, and the three-phase load corresponding to each load unit is reasonably allocated to balance the three-phase load of the transformer.

• Adopting an intelligent charging management system: dynamically allocating and optimizing the charging power of multiple charging stations through intelligent algorithms, automatically adjusting the output power of each charging station according to the charging demand of vehicles and the load situation of the power grid, to avoid excessive concentration or imbalance of three-phase loads.