Laboratory for Photovoltaic Systems

BFH’s inverter lab specialises in three areas:

• Grid connection of inverters (smart-grid functions of inverters, network and system protection, fault ride-through FRT)
• Electromagnetic compatibility (EMC)
• Efficiency measurements

In addition to purely PV-grid connection inverters, off-grid and PV battery systems are also tested. Close collaboration with the High-Voltage Systems Lab enables testing of inverters’ resilience against direct or indirect lightning strikes. The Laboratory for Photovoltaic Systems is part of the Energy Storage Research Centre in Biel which means it has access to high-quality infrastructure for testing batteries and related systems.

The IT backbone of the inverter lab is the browser-based MUSCLE concept developed at BFH. This open-source concept uses Python programmes which control simulators and read measuring devices via embedded systems.

The PV components research area covers topics relating to PV modules, bypass diodes, solar glass, connectors and other components required for a PV system. The PV laboratory uses various indoor and outdoor measuring devices to analyse the properties, quality and reliability of PV components.

One speciality is the characteristic curve measuring device developed at the PV laboratory for the automatic recording of characteristic curves of PV modules in the field. This allows, for example, the effects of partial shading at module level to be monitored in detail in pilot projects.

The research and service offerings include

• Measurement of PV modules in the laboratory and in the field
• Characteristic curve measurements of PV modules
• Infrared images (hot spots)
• Electroluminescence images (cell fractures)
• Ultraviolet fluorescence images (cell fractures, degradation)
• Steady-state analyses with solar simulator (hot spots, heating effects)
• Benchmarking of PV modules

The PV systems research area focusses on the interaction of PV components in practice and on issues relating to photovoltaics in the context of the Swiss electricity supply.

The research and service offerings include

• Agri-photovoltaic systems: Together with our colleagues at the School of Agricultural, Forest and Food Sciences (HAFL), we are investigating the interplay between electricity and food production
• Alpine PV systems: Together with the PV laboratories of ZHAW, SUPSI and OST, we are investigating technical issues relating to alpine PV systems.
• Studies, calculations and simulations: We have various commercial and self-developed software and tools for analysing PV systems.
• Realisation of measurement campaigns for PV systems

Every year, BFH students write project, Bachelor's and Master's theses at the PV laboratory. The following work has been realised in recent years (selection):

• Concept and construction of a characteristic curve measuring device for PV modules
• Concept and construction of an LED sun simulator
• Development of a measurement method for glare on PV systems
• Comparison of different simulation tools for bifacial vertical PV systems

If you are an industrial partner and would like to tender for work in the PV Laboratory's area of expertise, you are welcome to contact the PV Laboratory. In order for a paper to be put out to tender, it must contain at least one research question that is not currently a standard service in the PV industry.

BFH’s Laboratory for Photovoltaic Systems has the following facilities:

• A range of PV systems of various ages and based on different technologies
• Inverter lab with programmable DC and AC sources and sinks for inverter testing up to 100 kVA
• Test bench for module inverters and power optimisers
• High-Voltage Systems Lab for direct and indirect lightning strikes, surge-voltage generator (direct and alternating current applications)
• Stationary and mobile testing facilities for measuring electromagnetic fields
• Sun simulator and flasher
• Electroluminescence measuring equipment
• Ultraviolet fluorescence measuring equipment
• Mobile test equipment (characteristic curve measuring devices, thermographic cameras)
• Climatic chambers for humidity/heat/cold tests
• Connector test bench for analysing the ageing of PV connectors

The extensive testing equipment of the Energy Storage Research Centre in Biel can also be used.
 

The Laboratory for Photovoltaic Systems’ main external partners include the following organisations and companies:

• Mont-Soleil solar power plant and research center

• 3S Solar Plus AG

• Swissolar

• Swiss Federal Office of Energy SFOE

• Innosuisse

• BKW Energie AG

• Genossenschaft Elektra, Jegenstorf

Various private clients (in particular manufacturers of products) are confidential and are not named.

The PV laboratory and Prof Dr Christof Bucher as head of the PV laboratory perform the following functions and memberships:

• Comité Électrotechnique Suisse (CES), electrosuisse (Vorstandsmitglied)

• IEC TC 8: System aspects of electrical energy supply

• IEC SC 8A: Grid Integration of Renewable Energy Generation

• IEC SC 8B: Decentralized Electrical Energy Systems

• IEC TC 82: Solar photovoltaic energy systems

• IEA PVPS Task 13: Reliability and Performance of Photovoltaic Systems

• IEA PVPS Task 14: High Penetration of PV Systems in Electricity Grids

• CES TK 82: Photovoltaische Solarenergie-Systeme (Vorsitzender)

• Swissolar Fachkommission PV Technik (Vorsitzender)

• Sahay Solar, Dozententeam

• Verein Arbeitsgemeinschaft für dezentrale Energieversorgung Burgdorf (ADEV Burgdorf, Vorstandsmitglied)