Mild Hybrid Powertrain Controller Feedforward PI Compensation
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Solution Overview
Problem
Mild hybrid powertrain controls often suffer from lower than desired current output during torque assist operations and current reversal, leading to decreased efficiency, energy storage system degradation, and substandard vehicle performance, particularly at higher or lower engine speeds and loads.
Innovation Solution
A controller is implemented to receive electrical machine power commands, process them using feedforward controls to compensate for power electronics inaccuracies and proportional integral (PI) controls to account for power losses, providing a compensated machine power command to accurately control the electrical machine, thereby correcting for inaccuracies and inefficiencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional mild hybrid controls are used to command torque assist operation, then the system attempts to provide desired torque assist, but the actual current output is lower than desired and current reversal occurs
Solution Approach 1:
The control system implements feedback mechanisms by monitoring actual current measurements from the energy storage system and comparing them against commanded values. This feedback loop enables the system to detect deviations caused by power electronics inaccuracies and adjust control commands accordingly, preventing current reversal and ensuring accurate current output during torque assist operations.
Solution Approach 2:
The system dynamically adjusts control parameters based on operating conditions, particularly at higher and lower engine speeds where problems occur. By changing control parameters in response to measured deviations, the system compensates for power electronics inaccuracies and maintains reliable torque assist operation across the full operating range.
2Power
If conventional mild hybrid controls command torque assist at higher engine speeds or loads, then torque assist is attempted, but current reversal occurs causing power generation instead
Solution Approach 1:
The control system applies preliminary corrective actions by anticipating and compensating for power electronics inaccuracies before they cause current reversal. The feedforward control component pre-adjusts commands based on known inaccuracies, while feedback control detects early signs of reversal tendency and applies counteracting corrections, preventing the harmful current reversal effect from occurring.
Solution Approach 2:
The control system introduces an intermediary compensation mechanism that mediates between the commanded torque assist and the actual electrical machine output. This intermediary control layer processes commands through feedforward and feedback compensation, filtering out inaccuracies that would otherwise cause current reversal, and delivering corrected commands to the electrical machine.
3Device complexity
If conventional mild hybrid controls are used, then system simplicity is maintained, but efficiency decreases and energy storage system function degrades
Solution Approach 1:
The control system implements self-service by autonomously monitoring its own performance through current measurements and automatically compensating for its own inaccuracies. The feedforward and feedback control mechanisms enable the system to self-correct without external intervention, maintaining efficiency and preventing energy storage system degradation while adding minimal complexity.
4Ease of operation
If conventional mild hybrid controls operate at lower engine speeds or loads, then operation is attempted, but current reversal occurs neither generating power nor providing torque assist
Solution Approach 1:
The control system dynamically adapts its behavior based on engine speed and load conditions. At lower engine speeds or loads where problems occur, the control system actively monitors current measurements and dynamically adjusts commands through feedback compensation, ensuring reliable operation across the entire operating range including conditions where conventional controls would fail.
Data Source
AI summary
Mild hybrid powertrain controls and apparatuses, methods and systems including the same are disclosed. One exemplary embodiment is a mild-hybrid system comprising an engine, an electrical machine, power electronics, an energy storage system, and an electrical load. The system includes a controller structured to receive an electrical machine power command based upon a power allocation to the electrical machine, process the electrical machine power command with feedforward controls structured to compensate for an inaccuracy associated with the power electronics, process the electrical machine power command with proportional integral (PI) controls structured to compensate for a power loss associated with one or more electrical loads, provide a compensated machine power command based upon the processing with the feedforward controls and the processing with the PI controls, and output the compensated machine power command to control the electrical machine.