Regenerative Braking Inverter Control for Adaptive Deceleration
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Solution Overview
Problem
Existing motor vehicle systems lack adaptive control methods for power electronics to optimize regenerative braking based on varying driving situations, leading to inefficiencies in energy conversion and potential overcharging of the energy storage system.
Innovation Solution
Implementing a control unit that selects between block clocking and space vector pulse width modulation methods based on driving situations, using sensors to determine emergency braking, gradient, and energy storage state, to optimize regenerative deceleration torque and prevent overcharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single control method is used for regenerative braking, then the control system is simple, but the system cannot optimize energy conversion under varying driving situations
Solution Approach 1:
The control system dynamically selects between block clocking and space vector PWM methods based on real-time driving situations (emergency braking vs. standard conditions). This dynamic adaptation allows the system to optimize regenerative braking performance for each situation without requiring a completely complex multi-method control architecture, resolving the contradiction between adaptability and complexity.
Solution Approach 2:
The system changes control parameters by switching between two distinct control methods (block clocking with 180-degree conduction and space vector PWM with 120-degree conduction) based on driving situation. This parameter change approach enables the system to adapt to different operating conditions while maintaining a relatively simple control structure that only needs to select between predefined control strategies.
2Speed
If block clocking method is used for regenerative braking, then rapid deceleration is achieved, but energy conversion efficiency is reduced
Solution Approach 1:
The system dynamically switches between block clocking and space vector PWM based on the driving situation. During emergency braking, block clocking provides rapid deceleration despite lower efficiency. During standard driving conditions, space vector PWM optimizes energy conversion. This dynamic selection resolves the contradiction by allowing the system to prioritize deceleration speed when needed and energy efficiency when possible.
Solution Approach 2:
The control system periodically evaluates driving situations and switches between control methods accordingly. This periodic assessment and switching allows the system to alternate between block clocking (for rapid deceleration) and space vector PWM (for efficient energy conversion) based on real-time conditions, resolving the trade-off between deceleration speed and energy efficiency.
3Loss of energy
If regenerative braking is continuously optimized for energy conversion, then energy efficiency is improved, but the risk of overcharging the energy storage system increases
Solution Approach 1:
The control system dynamically adjusts the regenerative braking strategy based on the state of charge of the energy storage system. When the system is near full charge, it switches to block clocking method which generates less electrical energy but provides sufficient deceleration. This dynamic adjustment prevents overcharging while maintaining energy efficiency during normal operation, resolving the contradiction between energy conversion optimization and overcharging prevention.
4Reliability
If friction braking is used instead of regenerative braking, then deceleration reliability is ensured, but energy recovery is lost
Solution Approach 1:
The control system periodically evaluates whether to use regenerative braking or friction braking based on driving situation and energy storage state. During emergency braking situations, it uses regenerative braking with block clocking for reliable deceleration. During standard conditions with sufficient energy storage capacity, it uses space vector PWM for optimized energy recovery. This periodic evaluation and switching resolves the contradiction between deceleration reliability and energy recovery.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances regenerative braking efficiency and prevents overcharging by adaptively controlling power electronics, ensuring rapid deceleration in emergencies and efficient energy conversion in standard driving conditions.
Implementation Method 1
When the electric machine is operated in generator mode, the rotation of the rotor induces alternating voltages in the phases, generating a regenerative braking torque.
Data Source
Figure 1~2
AI summary
The invention relates to a method for operating a motor vehicle (1) which has an electrical machine (7) with at least three phases, an electrical energy store (13) and a power electronics system (12) having a plurality of switching elements, wherein the switching elements of the power electronics system (12) are actuated for electrically connecting the phases to the energy store (13), in order to produce a generator deceleration moment. Provision is made for a driving situation of the motor vehicle (1) to be determined, wherein an actuation method is selected from amongst a group of at least two possible actuation methods according to the determined driving situation, and wherein the switching elements are actuated according to the selected actuation method.