An optimum method for maximum power point tracking in photovoltaic systems

Abstract

In this paper, we present a maximum power point technique for photovoltaic (PV) systems based on the array optimal conductance. We have shown that this conductance depends on the cell junction current which is difficult to estimate due its high non-linearity, therefore, an analytical expression is derived to simplify its use. The results show that the proposed technique gives good results with a minimum output power error and responds perfectly to abrupt change in solar radiation.Index Terms-Maximum power point tracking (mppt), optimal conductance, junction current.

Maximum Power Point Tracking Methods for PV Systems

“…However, when rapid changes in irradiance occur, these methods have a tendency to lose the MPP and initially track in the wrong direction [20][21][22]. The IncCond technique experiences the same limitations as the P&O and HC implementations.…”

“…Another key limitation of HC approaches is that these are unable to distinguish between local and global maxima, as the method will simply track until it first locates a MPP regardless of if this is the global MPP (GMPP). In the event that a change in the environmental conditions occurs simultaneously with an applied perturbation, these techniques do not have the intelligence to distinguish which of these factors has resulted in the change in power [20]. For instance, if a positive step in voltage is applied at the same time that the irradiance increases, the power at the operating point may increase regardless of if continuing to step in this direction will lead to the MPP.…”

Adaptive neuro‐fuzzy based solar cell model

“…The second current involved in the cell output current is the junction current I d given by expression (2), where the reverse saturation current is expressed as [1, 19,26]…”

“…Knowing that the shunt resistance is much higher than the series one ( R sh 〉 R s ), it implies that the shunt current is very small [5, 24]; consequently, the solar cell model can be simplified and rewritten as [16] In fact, the cell current depends on the irradiance, cell temperature and cell voltage, so (10) will be where I ph is linearly dependent on the irradiance and the cell temperature as follows [2, 5, 16, 25] The second current involved in the cell output current is the junction current I d given by expression (2), where the reverse saturation current is expressed as [1, 19, 26] where I rr is the reverse saturation current at STC, and E G is the band gap energy of the semiconductor.…”

“…The output current–voltage relationship is given by the following expressions [14, 16–19] where I ph is the photocurrent, I d is the junction current, I sh is the shunt current, I o is the reverse saturation current, R s is the series resistance, R sh is the parallel resistance, A is the diode factor, k is the Boltzmann's constant, T is the cell temperature and q is the electron electric charge.…”