Cascaded Bidirectional Converter Topology for 700 W Transformerless High Frequency Inverter
- PDF / 2,252,125 Bytes
- 12 Pages / 595.276 x 790.866 pts Page_size
- 54 Downloads / 197 Views
Cascaded Bidirectional Converter Topology for 700 W Transformerless High Frequency Inverter K. Suryanarayana1
· H. N. Nagaraja2
Received: 2 February 2016 / Revised: 30 April 2016 / Accepted: 15 June 2016 © Brazilian Society for Automatics–SBA 2016
Abstract Home inverter is an important system which provides uninterrupted power supply for domestic requirements. Most of the existing systems use line frequency transformers to generate the desired sinusoidal voltage and exhibit poor load regulation and efficiency. Under spurious conditions, reliable and stable operation of the inverter is a primary requirement. In this paper, 3-stage bidirectional (boost and buck) cascaded converter topology is proposed to boost an input battery voltage from 12 to 375 V and vice-versa. DC link is connected to H-bridge converter to obtain a desired sinusoidal output voltage. In the topology, first and third stages are non-isolated boost converters and second stage is a buck derived push–pull converter. Push–pull configuration of the 2nd stage provides electrical isolation to source from high voltage DC bus. Cascaded DC–DC converter outputs are regulated by designing an average current mode control and instantaneous voltage control is designed for Hbridge inverter. Hardware is designed and developed using digital signal controllers to supply 700 W domestic load. Experiments are conducted for different linear, nonlinear and dynamic load variations. Keywords Multiphase · Boost converter · Push–pull converter · H-bridge inverter · State-space modeling · Average current mode control
B
K. Suryanarayana [email protected] H. N. Nagaraja [email protected]
1
NMAM Institute of Technology, Nitte, Karkala 574110, India
2
Noble Group of Institutions, Junagadh 362310, India
1 Introduction Power failure is a commonly observed phenomenon in dayto-day life. The applications like servers, ATMs, health care systems and domestic loads need an uninterrupted supply for proper functioning. Uninterruptible power supply (UPS) is essential for smooth functioning of systems, under the power failure conditions. The ideal scenario is to have a UPS with zero transfer delay when grid power supply fails. Failure detection and transfer from main to UPS mode will take time depending on the type of load (linear or nonlinear) connected to the system. Commonly available systems in the market are designed with transformers at line side. Transformer-based UPS systems in general are based on H-bridge connected to a line frequency step up transformer. Different modulation schemes are used to generate the desired sinusoidal voltage. The primary side of the transformer need to carry very high current in the order of 75–80 A at 12 V under full load conditions for 700 W system. Design of such line frequency transformers is complicated and make the system bulky and heavy. Physical dimension and weight of the system will increase with increased VA rating of the UPS. Laboratory experiments of line transformer-based systems show that overall system efficiency is
Data Loading...
