Feed Forward Dissipation Control for Fast Electric Direction Changes
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Solution Overview
Problem
Existing systems for electric drive machines face challenges in managing high electrical currents during directional changes, leading to potential damage and inefficiencies due to delayed responses in energy dissipation and charging systems, particularly when decelerating or changing directions on slopes.
Innovation Solution
Implementing a feed forward controller that anticipates and activates a load system based on charging current limits, using sensors and a PID controller to manage energy dissipation or storage during deceleration, ensuring seamless power management without exceeding charging limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the electric drive system attempts to change driving direction quickly, then the response time for directional change is reduced, but high currents pass through the electric drive components causing potential damage
Solution Approach 1:
The feed forward controller activates the load system in advance based on anticipated deceleration events or charging current limits, rather than waiting for feedback signals. This preliminary action prepares the system to handle high currents during directional changes, preventing component damage while maintaining quick response times.
2Reliability
If the operator uses the service brake system to stop the machine before directional change, then high current damage is prevented, but the overall time for directional change increases due to the stop-and-go sequence
Solution Approach 1:
The feed forward controller maintains continuous control of the load system throughout the deceleration and directional change process, eliminating the need to disengage brakes and re-engage propulsion. This continuous action allows the machine to change direction smoothly without complete stops, reducing the time loss while protecting components through controlled current management.
3Device complexity
If the charging system responds delayed to electrical load during motor braking, then system complexity is reduced, but energy dissipation efficiency decreases and overheating occurs
Solution Approach 1:
The feed forward controller anticipates deceleration events and activates the load system before the charging system would normally respond. This preliminary activation ensures immediate energy dissipation capability is available, preventing overheating and maintaining efficiency without requiring complex real-time response mechanisms.
4Loss of time
If the feed forward controller activates the load system based on charging current limits, then energy dissipation delays are minimized, but the control system complexity increases
Solution Approach 1:
The feed forward controller uses pre-established charging current limit thresholds to trigger load system activation in advance of actual deceleration events. This approach minimizes energy dissipation delays by having the system ready before needed, while keeping control architecture relatively simple through the use of predetermined thresholds rather than complex real-time calculations.
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
The feed forward controller minimizes delays in energy dissipation, prevents overheating, and maintains consistent deceleration, thereby protecting the charging system and improving operational efficiency during directional changes and slope traversals.
Implementation Method 1
the electric motor is configured to provide propulsion for the machine by driving the wheels or travel mechanisms of the machine... the electric motor to provide propulsion for the machine
Implementation Method 2
a battery system configured to provide power to the electric motor
Implementation Method 3
a load system such as a parasitic load, auxiliary energy storage, or energy dissipation system configured to receive power produced by the electric motor
Data Source
AI summary
This disclosure describes a feed forward control system for engaging a dissipative energy system for dissipating energy produced by a motor of an electrically-powered machine as a result of deceleration of the machine, for example to decelerate and execute a directional change for the machine. The control system includes a feed forward system that engages based on an input signal to spool up and power-on a dissipative energy system of the machine such that as energy is produced, the energy may be divided between the dissipative system and the charging system of the machine. The feed forward controller operates based on a function of a charging current limit of the battery, inversely proportional to the charging current limit.