Title :
Dynamic properties of PCM-controlled current-fed boost converter in photovoltaic system interfacing
Author :
Leppaaho, J. ; Suntio, T.
Author_Institution :
Dept. of Electr. Energy Eng., Tampere Univ. of Technol., Tampere, Finland
fDate :
Aug. 30 2011-Sept. 1 2011
Abstract :
The interfacing of photovoltaic (PV) energy source is known to be problematic due to the highly varying terminal characteristics of the energy harvesting unit, generally a PV generator. Therefore, its power flow needs to be regulated and a certain maximum power point (MPP) traced. The switched-mode dc-dc converters are conventionally used to interface energy sources possessing constant-voltage nature. These voltage-fed (VF) converters have been used as a basis for the MPP-tracking devices as well. It is observed, however, that the performance of such converter is not optimal in this purpose, because the PV generator possesses a current-source nature. Therefore, an additional capacitor is usually added between the source and the converter to enhance the constant-voltage properties of the source. The PV regulation is also performed by controlling the input voltage. These modifications change, however, the VF converter into a current-fed (CF) converter, which has totally different static and dynamic behavior than the original converter. This implicit duality transformation also causes a situation, where the usage of conventional inner-loop control, such as peak-current-mode (PCM) control, may lose its beneficial nature or the converter may even cease to operate in a stable manner. This paper analyses the static and dynamic properties of the buck-derived PV converter known as a dual or CF boost converter under the input-voltage and PCM controls. Investigations show that the conventional PCM control is not recommended to be used in the CF converters due to its inherent VF properties.
Keywords :
DC-DC power convertors; electric current control; energy harvesting; load flow control; maximum power point trackers; photovoltaic power systems; power generation control; switching convertors; voltage control; MPPT; PCM-controlled current-fed boost converter; PV generator; PV regulation; VF converter; capacitor; constant-voltage property; energy harvesting unit; implicit duality transformation; inner-loop control; input-voltage control; maximum power point tracker; peak-current-mode control; photovoltaic system interface; power flow regulation; switched-mode DC-DC converter; voltage-fed converter; Admittance; Generators; Impedance; Phase change materials; Photovoltaic systems; Switches; Transfer functions; converter control; device characterisation; photovoltaic; renewable energy systems; switched-mode power supply;
Conference_Titel :
Power Electronics and Applications (EPE 2011), Proceedings of the 2011-14th European Conference on
Conference_Location :
Birmingham
Print_ISBN :
978-1-61284-167-0
Electronic_ISBN :
978-90-75815-15-3