Performance analysis of a DSO-optimized fuel cell-fed DSTATCOM with high-gain boost converter for power quality enhancement

Abstract The increase in the usage of nonlinear loads and highly sensitive industrial machinery has called for an effective design of power quality improvement apparatus which guarantees reliable output. An innovative design of an advanced three-phase distribution static compensator (DSTATCOM) topology is presented in this paper to fulfil the dual objective of providing reactive power support and reduction of current harmonics in the grid-connected system. Two distinct high-gain DC–DC converters are suggested as power sources to feed the DC-bus of the DSTATCOM; namely, floating interleaved boost converter (FIBC) and quadratic high gain boost converter (QHGBC). High gain can be achieved by the FIBC while reducing the input current ripples by employing a method called interleaving which utilizes the concept of interconnecting two boost converters in series on a single magnetic core hence protecting the source from high-frequency interference. The QHGBC, on the other hand, achieves the step-up ratio using a switched inductor-capacitor topology where two converters are interconnected in cascade form, resulting in quadratic voltage gain hence a smaller duty cycle needed to achieve the step-up ratio unlike that of the conventional topology. For proper synchronization of the DSTATCOM to the distorted supply voltage, a dual second order generalized integrator phase locked loop (DSOGI-PLL) is applied and controlled with a third order loop filter. DC-bus voltage level control is accomplished using a Fuzzy control strategy where Dolphin Swarm Optimisation (DSO) is used to obtain optimized control parameters. Tuning of the parameters was done using the integral transient time index. The simulation analysis of DSTATCOM with fuel cell source shows that the designed controller has been able to reduce the current distortion in the source from 26.01 to 2.19% with nonlinear RL load and from 31.84 to 2.83% with nonlinear RC load, which meets the IEEE-519 guidelines. Moreover, the optimal controller is capable of controlling the DC-link voltage to 700 V in 0.1 s with no overshoot. For the realtime performance analysis, a lab scale prototype with an emulated fuel cell DC input is developed in the laboratory. The experimental results are analyzed and the efficacy has been achieved by the proposed controller.