Regenerative Braking Control for Downhill Bus Voltage Stability
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Solution Overview
Problem
Hybrid lawn and garden vehicles face challenges in managing excess electricity generated when traveling downhill, which can lead to uncontrolled power regeneration and potential safety issues due to unpredictable vehicle responses.
Innovation Solution
Implementing a control system with Four Quadrant Motor Control and a control algorithm that uses current sensing and slope detection to limit the vehicle's speed when going downhill, thereby reducing excess power regeneration and stabilizing the system power bus voltage, allowing the generator to either consume or store the excess energy safely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the vehicle travels downhill, then gravity generates excess electricity through power regeneration, but this causes uncontrolled power regeneration and unpredictable vehicle responses
Solution Approach 1:
The control system continuously monitors bus voltage and power regeneration levels, and automatically adjusts ground drive motor speed to maintain bus voltage within a target range. This closed-loop feedback control prevents uncontrolled power regeneration and ensures predictable vehicle responses by dynamically balancing power generation and consumption.
Solution Approach 2:
The system dynamically adjusts the operating parameters of ground drive motors based on real-time conditions during downhill travel. By varying motor speed and power regeneration levels according to bus voltage feedback, the system adapts to changing gravitational energy input while maintaining controlled and predictable vehicle behavior.
2Loss of energy
If the vehicle speed is reduced to match power consumption, then excess power regeneration is prevented, but this may reduce productivity during downhill travel
Solution Approach 1:
The control system changes the operating parameters of ground drive motors dynamically during downhill travel. By adjusting motor speed and power regeneration levels based on bus voltage feedback, the system optimizes the balance between preventing excess power regeneration and maintaining adequate productivity, allowing faster speeds when power consumption capacity permits.
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
This solution effectively manages excess electricity by reducing the vehicle's speed to match power consumption, preventing uncontrolled power regeneration and ensuring consistent operator control, thus enhancing safety and efficiency.
Implementation Method 1
an internal combustion engine driving a generator to power ground drive motors
Implementation Method 2
ground drive motors to power the output wheels
Implementation Method 3
When such a vehicle is going down a slope (or grade), excess electricity can be created
Data Source
AI summary
A utility vehicle with regenerative braking is disclosed. The utility vehicle includes a system power bus, a battery coupled to the system power bus, at least one electric drive motor configured to generate power through the regenerative braking and supply the power onto the system power bus, and a first controller configured to decrease a maximum travel speed to reduce an amount of the power generated through the regenerative braking when the battery is fully charged and the power is greater than a power consumption limit.