Abstract:
Inductive wireless charging (IWC) has an advantage over plugged-in chargers in terms
of safety, efficiency, and convenience. However, the resonance, and hard switching of
full-bridge inverters is a major research problem that needs to be addressed. The
Current/voltage regulation and ZVS operation can be accomplished in IWC systems
with supplemental dc-dc converter stages but at a higher power loss due to the
additional conversion stage. Zero-voltage-switching operations over a wide load range
are becoming progressively critical for enhancing system efficiency and reducing
interference problems. Therefore, Soft Switching and LCC-compensated Zero Voltage
Switching (ZVS) are proposed as solutions of Hard Switching on the inverter side of
the WPT system. In the Wireless power transfer (WPT) system of Electric Vehicles,
the primary circuit is connected to the secondary circuit through a loosely coupled
transformer. Hard Switching in inverters causes a huge power loss in the form of heat.
Low power factor losses at the secondary, as well as the primary side, incorporated
using series-series (SS), series-parallel (SP), and LCC compensations. This research
recalls an extensive comparison study of SS, SP, PS, PP, and LCC compensation
techniques based on the Input Impedance and Power Efficiencies by a varying Air gap
between loosely coupled transformers. Air gap distance starts from 50 mm and
increases to 100mm, 150mm, 200mm, and 250mm. A comparison table has been
drawn for five compensation techniques for the 7-KW WPT system. The simulation
was verified by running a hardware-in-loop (HIL) system. At a 50mm distance, the
efficiency of SS Compensation was measured 82% while SP Compensation’s
efficiency was measured 81%. Author proposed that the ZVS-operated WPT system
with LCC compensation is better than SS and SP compensation. Results indicate that
the proposed work presents an efficient comprehensive analysis of compensation
topologies with zero-volt switching feature. All simulations were verified using the
PSIM simulation tool.
