Electric Drive Direction Control via Dynamic Braking Torque
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Solution Overview
Problem
Electric drive machines face challenges when attempting to change driving direction quickly, as high power requirements can lead to excessive currents damaging components, and existing systems do not effectively manage this transition before the power is sufficiently low.
Innovation Solution
A method and system that receive a signal for direction change, determine if the machine's speed is above a threshold based on electric motor parameters, and apply braking torque to the travel mechanisms via the accelerator pedal position until the speed reaches the threshold, allowing safe direction changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the operator attempts to change the driving direction quickly, then the response time is reduced, but the current through the electric drive system becomes excessively high which may damage components
Solution Approach 1:
The control system performs preliminary braking action before the direction change is initiated. When a direction change is detected, the system first applies brake torque to reduce the machine speed to a threshold level, then proceeds with the direction reversal. This preliminary speed reduction prevents excessive current from occurring during the direction change, thereby protecting the electric drive components while still enabling relatively quick direction changes.
2Reliability
If the operator engages the brake system to stop the machine before changing direction, then component damage is prevented, but the time required for direction change increases
Solution Approach 1:
The braking system operates dynamically rather than statically. Instead of requiring a complete stop before direction change, the system applies variable brake torque that reduces speed to a threshold level sufficient to prevent excessive current, then releases the brakes to allow immediate direction reversal. This dynamic approach maintains component protection while significantly reducing the time required for direction changes compared to complete stopping.
3Productivity
If the machine operates at high speed, then productivity is improved, but the ability to change direction safely is reduced
Solution Approach 1:
The system performs preliminary braking action whenever a direction change is detected, regardless of the current speed. This preliminary action reduces the speed to a safe threshold level before the direction reversal occurs, enabling the machine to maintain high operating speeds for productivity while ensuring safe direction changes by temporarily reducing speed only when necessary.
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
Enables safe and efficient direction changes in electric drive machines by controlling speed and torque, preventing component damage and ensuring smooth transitions between forward and reverse directions.
Implementation Method 1
The electric motor is typically configured to provide propulsion for the machine by driving the wheels or travel mechanisms of the machine
Implementation Method 2
applying a braking torque to at least one travel mechanism of the machine in response to a signal indicative of an accelerator pedal position until the speed reaches the threshold
Data Source
AI summary
The disclosure describes, in one aspect, a method for changing a direction of a machine that is moving in a first direction. The method includes the step of receiving a signal indicative of an intention to change the direction of the machine to a second direction. The method also includes the step of determining whether a signal indicative of a speed of the machine is greater than a threshold based at least in part on an electric motor parameter. Finally, the method includes the step of applying a braking torque to at least one travel mechanism of the machine in response to a signal indicative of an accelerator pedal position until the speed reaches the threshold.