Application of Negative DC Bus Embedded Type Z-Source Inverters in Hybrid Electrical Vehicles

Abstract

This paper presents a Z-source inverter control approach used to control power from the fuel cell, power to the motor, and state of charge (SOC) of the battery for fuel cell (FC)—battery hybrid electric vehicles FCHEV). Traditional pulse width modulation inverter always requires an extra dc/dc converter to interface the battery in FCHEV’s.Z-source inverter has the capability to boost voltage and invert at single stage itself. By substituting one of the capacitors in the Z-source with a battery and controlling the shoot through duty ratio and modulation index independently, one is able to control the FC power, output power, and SOC of the battery at the same time. The advantage of negative dc bus type embedded type was reducing the requirement of battery size in vehicular applications. These facts make the proposed Z-source inverter highly desirable for use in FCHEVs, as the cost and complexity is greatly reduced when compared to traditional Z-source inverters. These new concepts will be demonstrated by simulation results.

Keywords: Z-source inverter, negative dc bus embedded type Z-source inverter Fuel cell hybrid electric vehicles (FCHEV), pulse width modulation (PWM), state of charge (SOC).