HEV Energy Management Control System Using Feedforward Feedback
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Solution Overview
Problem
Existing hybrid electric vehicle (HEV) control systems face complexity in managing energy distribution, particularly in separating speed and torque determinations, which affects fuel economy and efficiency.
Innovation Solution
A control system that simplifies energy management by separating speed and torque into two independent control variables (gear selection and battery power request), using a feedforward battery power value and feedback battery power modification to calculate the battery power request, and disabling feedback loops under certain conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional HEV control system manages energy distribution with integrated control logic, then the system can coordinate engine and motor operations, but the control complexity increases and fuel economy optimization is reduced
Solution Approach 1:
The control system is segmented into two independent control variables: gear selection (speed determination) and battery power request (torque determination). This separation allows each control function to be optimized independently, simplifying the overall control logic while improving fuel economy through specialized optimization of each subsystem.
2Adaptability or versatility
If the engine operates outside its high efficiency range to meet varying power demands, then the vehicle can respond to driver torque requests, but fuel economy deteriorates
Solution Approach 1:
The system changes operational parameters by using the electric motor to compensate for engine operation outside its optimal efficiency range. The motor can add or subtract power as needed, allowing the engine to operate in its high efficiency range while still meeting varying driver torque requests, thus maintaining both adaptability and fuel economy.
3Measurement precision
If feedback loops are continuously active to optimize battery power distribution, then energy management precision is improved, but control system complexity and computational load increase
Solution Approach 1:
The system implements feedback mechanisms to monitor actual battery power and compare it with the requested battery power, generating modification values that adjust the control strategy. This feedback approach maintains energy management precision while the independent control variable structure prevents excessive complexity by providing clear feedback paths.
Data Source
AI summary
A system and method for controlling energy distribution within a HEV powertrain are provided. A feedforward battery power value is generated in response to input indicative of a driver torque request. A feedback battery power modification value is generated in response to input indicative of actual battery power and the driver torque request. A battery power request is calculated based a sum of the feedforward battery power value and the feedback battery power modification value.