This paper presents an advanced control strategy for balancing the time-varying and unbalanced loads by using the fuel cell and battery under the grid-tied and off-grid operations. In the grid-tied operation, the fuel cell and the battery are coordinately controlled to balance the three-phase unbalanced active and reactive powers of the loads. In this case, the received three-phase active-reactive powers from the grid become completely balanced by the given strategy. In the off-grid, the diesel generator supplies the active-reactive powers of load and the unbalances are handled by coordinated operation of fuel cell and battery. As well, the voltage of off-grid system is improved by injecting adequate reactive power to the system through the fuel cell, battery and diesel generator. The dynamic stability of the system is evaluated under non-linear disturbances like grid outage and single-phase fault. The time-varying unbalanced active-reactive powers are balanced under both off-grid and grid-tied states by implementing the proposed model. The purpose of the proposed control system is to balance the unbalanced load from point of view of the upstream grid at all time periods. In order to realize such function in the model, the load is modeled by two terms including the balanced and unbalanced parts. The unbalanced share is supplied by the inverters (DC bus) and the balanced term of load is supplied by the grid. The designed system is resilient under the events like grid outage and short circuits. As well, the system properly regulates and controls the load variations and unbalances.

本文提出了一种先进的控制策略，通过在并网和离网操作下使用燃料电池和电池来平衡时变负载和不平衡负载。在并网运行中，对燃料电池和电池组进行协调控制，以平衡负载的三相不平衡有功功率和无功功率。在这种情况下，通过给定策略从电网接收的三相有功-无功功率将变得完全平衡。在离网状态下，柴油发电机提供负载的有功-无功功率，并且通过燃料电池和电池的协调运行来解决不平衡问题。同样，通过通过燃料电池，电池和柴油发电机向系统注入足够的无功功率，可以改善离网系统的电压。在非线性干扰（例如电网中断和单相故障）下评估系统的动态稳定性。通过实现所提出的模型，时变不平衡有功-无功功率在离网和并网状态下均得到平衡。提出的控制系统的目的是在所有时间段从上游电网的角度平衡不平衡负载。为了在模型中实现这种功能，通过平衡和不平衡两个部分对负载进行建模。不平衡份额由逆变器（直流母线）提供，而负载的平衡项由电网提供。设计的系统在诸如电网中断和短路等事件下具有弹性。同样，系统可以适当地调节和控制负载变化和不平衡。