Solar energy is classified as an environment friendly renewable resource and it is potentially to mitigate the energy crisis. Photovoltaics (PV) is an effective solar energy conversion technique which can directly turns solar energy into electricity using semiconducting materials without having impact on the environment during the conversion. In a modern PV inverter, there is consist of semiconductors, magnetic devices, controllers, other passive and mechanical devices such as relays. Characteristics of the active and passive components are non-linear, and some non-linear controls such as sliding mode control and boundary control have been used in PV inverters. Moreover, the power source, PV panel, behaves non-linear as well, it makes challenges for a Real Time Digital Simulation (RTDS) system to simulate impacts of a PV inverter or a PV farm for a power grid due to the nonlinearities.
Power-hardware-in-the-loop simulation (PHILS) system consists of a Power source being interfaced with the Real Time Digital Simulator (RTDS). The loop acts as an interface to exchange power between the system emulated in RSCAD environment with the actual devices. The interface is basically built of amplifiers and analog/digital cards of low power levels (e.g. ±10V). The bidirectional interface amplifier required in the loop acts as a device to sink or source the power flow between software and hardware environment. This “Virtual Reality” approach can link an actual power electronics apparatus, such as PV inverter, to a public grid network in the RTDS. Therefore, PV inverter manufacturers can evaluate products with different grid conditions and situations to ensure the reliability. Public utility companies can benchmark and evaluable PV inverters using PHILS before any actual installation for a solar farm.
The presentation will demonstrate a PHILS testbed using the RTDS for evaluating a real single phase PV inverter. Moreover, design and implementation issues, system analysis and experimental results will be discussed.
Carl Ho, University of Manitoba