An enhanced DC-DC boost converter based stand-alone PV-Battery OFF-Grid system with voltage balancing capability for fluctuating environmental and load conditions

ABSTRACT

There is a requirement for a suitable DC-DC converter which can exhibit satisfactory performance in the case of OFF-Grid PV systems. This paper proposes a PV-Battery stand-alone system with an enhanced DC-DC boost converter and an efficient voltage balancing technique. The converter is designed to achieve the desired voltage gain at a lower duty-ratio as compared to the existing converter topology used in conventional stand-alone systems, thereby reducing the voltage stress across the switching devices. For extracting maximum power from the solar panel at every given point of operation, the Incremental Conductance Technique is used. A non-complex voltage balancing technique maintains the DC bus voltage constant with fast dynamic response. The system is highly reliable in case of converter fault and exhibits less initial transient time each time it is put to test. The performance of the proposed system is tested under varying input and varying load conditions with maximum overall system efficiency of around 93%. The stability of the system is investigated using a small signal model of the converter. The proposed stand-alone PV/Battery system is designed to handle a 1 KW load at 180 V DC voltage fed by 1.5 KW solar panel and 100Ah/24 V Li-ion Battery. The dynamic performance of the proposed system is verified through OPAL-RT 4510 platform.

KEYWORDS:

• OFF-Grid PV systems
• enhanced DC-DC boost converter
• duty ratio
• voltage balancing technique
• switching loss

Disclosure statement

No potential conflict of interest was reported by the author(s).