Decentralized Autonomous Hybrid Renewable Power Generation

Table 1

Some MPPT technique literatures for standalone WECS.

Author	EUE (%)	Control strategy	Content	References
Pan and Juan	about 90.2	ACC	Presents reduced harmonics, reliable, and cost effective adaptive compensation control (ACC) based MPPT for a microscale WECS. ACC improves dynamic response and more wind energy can be extracted during variable wind speed.	[154]
Nishida et al.	>95	PWM converter	Discusses cost effective, reliable, and wide speed range variable-speed wind-turbine MPPT controller using PWM inverter cascaded in series with a series-type 12-pulse rectifier for interior PMSG based WECS. The system has reduced voltage and current (&) harmonics and total losses in WECS is minimized.	[155]
Lo et al.	>90	OTC, PCM, CVM, DCM, and CCM	Investigates buck-type power converter based MPPT controller using pulsating-current battery charger for small-size PM wind turbine in standalone mode to obtain improved charging efficiency. Battery charger operates in discontinuous conduction mode (DCM) with constant on-time control (OTC) to achieve the desired pulsating current mode (PCM) operation. At the end of battery charging state, charger operates in the constant voltage mode (CVM) to prevent battery overcharging. Over speed protection of the wind turbine can be naturally obtained when the charger enters continuous conduction mode (CCM) operation.	[156]
Mendis et al.	>97	Power curve, vector control	Proposes tip speed ratio and pitch angle based MPPT for PMSG and DFIG based hybrid WECS-battery storage as standalone unit. Different control strategies have been developed and proposed for system module to achieve AC voltage and frequency regulation, DC-link voltage stability, and maximum power extraction in proposed standalone unit.	[157]
Zou et al.	>95	Characteristic power curve, DSP kit	Investigates power-curve based MPPT algorithm to obtain robust and cost effective control method for wind turbine systems. Conditions for stable MPPT operation have been determined based on the small-signal model. The transfer function for variation of wind speed to generator speed is determined to be of the first order. The simulation and experimental results confirm validity of proposed transfer function. Dynamic behavior of generator speed is independent of instantaneous wind speed but dependent on dynamics of the wind speed.	[158]
Cirrincione et al.	>90	GNG algorithm, FOC, VOC, DS1103, and DSP TMS320F240	Presents growing natural gas (GNG) based MPPT for variable-pitch WECS with IMs to meet need of maximum power range and constant power range. To cope up with constant power region, the blade pitch angle has been controlled on the basis of closed-loop control of mechanical power absorbed by the IM. MPPT technique included field-oriented control (FOC) for induction generator and voltage oriented control (VOC) for grid-connected inverter.	[159]
Dalala et al.	>90	PO algorithm	Discusses perturb and observe (PO) based MPPT algorithm for small scale WECS, using DC-side current as perturbing variable. Algorithm is best suited for both slow and high wind speed fluctuation, attaining enhanced stability as well as fast tracking capability.	[160]
Urtasun et al.	About 99.7	& control during PCM, CVM, DCM, and CCM modes	Evaluates robustness and power loss in a sensorless MPPT, for PMSG based small WECS incorporating a diode bridge, as compared to conventional curve based MPPT techniques. Due to fluctuating source, it is difficult to obtain optimum power curve and precise relation between dc current and the dc voltage, thus causing power loss.	[161]