Introduction

The following topics are covered in this lecture

• •  Power Flow Control

•  Power Flow Control in Series Hybrid

•  Power Flow Control in Parallel Hybrid

•  Power Flow Control in Series-Parallel Hybrid

Power Flow Control

Due to the variations in HEV configurations, different power control strategies are necessary to regulate the power flow to or from different components. All the control strategies aim satisfy the following goals:

• •  maximum fuel efficiency

•  minimum emissions

•  minimum system costs

•  good driving performance

The design of power control strategies for HEVs involves different considerations such as:

• •  Optimal ICE operating point: The optimal operating point on the torque-speed plane of the ICE can be based on maximization of fuel economy, the minimization of emissions or a compromise between fuel economy and emissions.

•  Optimal ICE operating line: In case the ICE needs to deliver different power demands, the corresponding optimal operating points constitute an optimal operating line.

•  Safe battery voltage: The battery voltage may be significantly altered during discharging, generator charging or regenerative charging. This battery voltage should not exceed the maximum voltage limit nor should it fall below the minimum voltage limit.