Application of Z-source inverter for traction drive of fuel cell-battery hybrid electric vehicles

This paper presents a Z-source inverter control strategy 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 pulsewidth modulation inverter always requires an extra dc/dc converter to interface the battery in FCHEVs. The Z-source inverter utilizes an exclusive Z-source (LC) network to link the main inverter circuit to the FC (or any dc power source). 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. These facts make the Z-source inverter highly desirable for use in FCHEVs, as the cost and complexity is greatly reduced when compared to traditional inverters. These new concepts will be demonstrated by simulation and experimental results.