Controller development of thermal management system for electric bikes

Abstract

This work aims to develop an advanced control strategy for a thermal management system (TMS) with both passive and active cooling/heating for an electric bike (e-bike) to primarily maintain temperatures of key powertrain components, including battery, inverter, motor, charger, and DC/DC converter. To establish the control strategy, various commands used in the TMS are first categorized into two types, binary commands (for valve control) and analog commands (for fan, pump, and compressor control). Next, the TMS control strategy is designed as the combination of a High-Level Controller (HLC) and a Low-Level Controller (LLC). The binary commands are derived using HLC, which takes ambient conditions, and temperatures of heat generated components as the inputs. Meanwhile, the LLC is used to calculate the analog commands through fuzzy inferences, after taking the outputs of HLC, ambient conditions, temperatures of the motor and battery, and electric power consumption of pumps as the inputs. A plant model of the e-bike powertrain integrating regenerative braking features with the TMS is built to support the control development and evaluation. Numerical simulations under the HWFET drive cycle have been carried out to realize the performance of the TMS using the proposed control strategy in terms of managing the key components’ temperatures and their power consumption.

Keywords

• Electric bike
• Thermal management system
• Passive and active cooling
• Refrigeration cycle
• Fuzzy logic controller