Integrated Testing and Measurement System for a PV Module-Based Transformer-Less DC/DC Converter
Creators: name: Chatterjee, U.
name: Pevere, A.
name: Mai, T.
name: De Breucker, S.
name: Driesen, J.
Publisher: name: WIP
Year: 2016
Subjects: Operation, Performance, Reliability and Sustainability of Photovoltaics
Balance of System Components

description: 32nd European Photovoltaic Solar Energy Conference and Exhibition; 2113-2117
description: Photovoltaic (PV) energy is one of the most promising future energy resource among all renewable energy sources. Many different
types of power converters are found for photovoltaic system in research literature and also in the market. These converters interface PV modules
with the AC or DC electric grid. In a typical PV system, the module is first connected with a DC-DC converter and then with a DC-AC inverter
in order to consume the produced power with the local loads (self-consumption) or to inject it to the AC network. The main role of the intermediate
DC-DC converter is to step up the low voltage of the PV module to an adequately higher value for connecting to the inverter stage. In case of
central power conversion structure, several PV modules are connected with one central inverter whereas for distributed power conversion each
module is interfaced with a converter. This second technique has several advantages, i.e. reduces power mismatch between PV modules,
performing MPP (maximum power point) tracking locally at module level, suitable for low/medium power applications.
PV modules generate different power levels depending on module configuration, operating pint and size. A DC-DC converter is
designed and built to be integrated at module level, capable of interfacing also “big” modules such as 96-cell modules. The converter is able to
boost directly from low output voltage of PV module to sufficiently high DC bus voltage that is suitable for connection to a single-phase DCAC
inverter. The converter is designed to address from very low voltage of PV module’s output in shading condition to high output voltage of
module in fully illumination condition. A low-level digital controller is developed and implemented with the converter. A real time PV system
is set in the laboratory and the converter is tested under different illumination conditions. A PV emulator is designed to be applied as an input of
the DC-DC converter for more convenient indoor testing. The PV emulator provides the flexibility to implement any kind of PV module available
in the market. Therefore, any real module can be implemented inside the emulator and used to test the converter. In this work, the aim is to
investigate the workability of the converter together with the controller in real PV scenario. A MPPT (maximum power point tracking) controller,
based on the standard P&amp;O technique, is also implemented to operate the module at the maximum power point.
This paper describes an integrated testing and measuring set-up meant to verify the operational principle of the developed modulebased
power converter and its usefulness as a distributed PV converter. It also explains the design and implementation of low-level control loop
that is integrated with the converter. The description of the overall system integration is included in following sections. Finally, some
measurement results of the system testing under static and dynamic irradiation conditions are presented.