Mission Profile-Oriented Control for Reliability and Lifetime of Photovoltaic Inverters

Abstract

With the aim to increase the competitiveness of solar energy, the high reliability of Photovoltaic (PV) inverters is demanded. For PV applications, the inverter reliability and lifetime are strongly affected by the operating condition that is referred to as the mission profile (i.e., solar irradiance and ambient temperature). Since the mission profile of PV systems is location-dependent, the inverter reliability performance and lifetime expectation can vary accordingly. That is, from the reliability perspective, PV inverters with the same design metrics (e.g., component selection) may be over-or under-designed under different mission profiles. This will increase the overall system cost, e.g., initial cost for over-designed cases and maintenance cost for under-designed cases, which should be avoided. This paper thus explores the possibility to adapt the control strategies of PV inverters to the corresponding mission profiles. With this, similar reliability targets (e.g., component lifetime) can be achieved even under different mission profiles. Case studies have been carried out on PV systems installed in Denmark and Arizona, where the lifetime and the energy yield are evaluated. The results reveal that the inverter reliability can be improved by selecting a proper control strategy according to the mission profile.

Insights on the Degradation and Performance of 3000 Photovoltaic Installations of Various Technologies Across the United Kingdom

“…Although there are various research efforts that focus on the degradation rate of PV systems worldwide [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24], there is lack of references describing the behaviour and degradation analysis of existing PV systems in the United Kingdom (temperate maritime climate). Therefore, in this paper, the data of 3000 PV installations across the UK are refined, and the extracted degradation rates are analyzed over a period of ten years (2008 to 2017).…”

“…Furthermore, in Thailand, the degradation rates were widely different, ranging from -0.5% to -4.9%/year [20]. A study conducted by [21] found that the PV degradation rate based on the long term of outdoor exposure in northern Thailand was equal to -1.5%/year. The degradation rates of PV modules in Japan, Singapore, and the Republic of Korea were reported equal to -1.15%/year [22], -2.0%/year [23], and -1.3%/year [24], respectively.…”

Centralized Thermal Stress Oriented Dispatch Strategy for Paralleled Grid-Connected Inverters Considering Mission Profiles

“…However, the lifetime of the grid-connected inverter in this configuration extremely suffers from the intermittent renewable energy generation. The generated power or the mission profile usually has a large variation in a short duration [2]- [5]. Due to the inline structure, the gridconnected inverter will bear such a variation of the real power from hundreds of kilowatts to several megawatts.…”

Investigation of single‐stage transformerless buck–boost microinverters

“…This strategy guarantees small investment in installation compared to other PV systems [4]. Even though, while comparing total solar market share, microinverter‐based PV contributes only 10% which is expected to grow up to 30% in 2020 [5, 6]. The main reason for this slow growth is that the average cost of such a PV system is comparatively greater than central, string inverter‐based PV system [7].…”