Dynamic Horsepower Allocation for Electric Dump Truck Drive Systems
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Solution Overview
Problem
In electrically driven dump trucks, the prime mover often stalls due to insufficient margin in horsepower allocation between loads and electric motors, leading to inefficient use of output horsepower.
Innovation Solution
A drive system with an electronic governor that controls fuel injection based on target revolution speed, incorporating speed sensing control to adjust available horsepower for electric motors, ensuring the prime mover does not overload and allowing full utilization of its output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the loss horsepower is set at a larger value with sufficient margin to prevent prime mover stalling, then the prime mover reliability is improved, but the electric motors cannot make full use of the prime mover output horsepower
Solution Approach 1:
The patent applies dynamics by making the loss horsepower value variable rather than fixed. The electronic governor dynamically adjusts the loss horsepower based on the difference between target revolution speed and actual revolution speed of the prime mover. When actual speed is lower than target speed, loss horsepower is increased to prevent stalling; when actual speed matches target speed, loss horsepower is reduced to allow full utilization of prime mover output by electric motors.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the revolution speed of the prime mover and using this information to adjust the loss horsepower calculation. The electronic governor receives feedback on actual revolution speed and modifies the loss horsepower allocation accordingly, creating a closed-loop control system that balances reliability and productivity.
2Device complexity
If the loss horsepower is set at a steady value, then the control system simplicity is maintained, but the total consumed horsepower may exceed prime mover output during traveling, causing stalling
Solution Approach 1:
The patent transforms the static loss horsepower value into a dynamic parameter that automatically adjusts based on operating conditions. The electronic governor calculates loss horsepower as a variable quantity determined by the speed difference between target and actual prime mover revolution, eliminating the need for overly complex control systems while ensuring reliability.
3Productivity
If the available maximum horsepower for electric motors is increased to improve acceleration performance, then the productivity is improved, but the prime mover may become overloaded and stall
Solution Approach 1:
The patent uses feedback control to dynamically determine the available maximum horsepower for electric motors. The electronic governor continuously monitors prime mover revolution speed and adjusts the horsepower allocation to electric motors based on the difference between target and actual speeds, ensuring optimal acceleration performance without overloading the prime mover.
Solution Approach 2:
The system dynamically adjusts the available maximum horsepower allocation based on real-time operating conditions. When the prime mover operates near its speed limit, the system automatically reduces the horsepower available to electric motors to prevent overload, while allowing maximum horsepower utilization during normal operating conditions.
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
Prevents prime mover stalling and enables electric motors to utilize the prime mover's output horsepower effectively, ensuring smooth acceleration and preventing overload.
Implementation Method 1
an alternating-current generator driven by the prime mover
Implementation Method 2
two electric motors, each of which is driven by the electric power supplied by the alternating-current generator
Data Source
AI summary
A drive system for an electrically driven dump truck is capable of enabling electric motors for traveling to make full use of the output horsepower of the prime mover up to an output limit of the prime mover. A target motor horsepower corresponding to an operation amount of an accelerator pedal is calculated and an available maximum horsepower for the electric motors out of the maximum output horsepower of the prime mover is calculated in response to the actual revolution speed of the prime mover. The horsepower coefficient corresponding to the instantaneous revolution speed deviation is calculated. The available maximum horsepower for the electric motors is modified by the horsepower coefficient to determine a second target motor horsepower. The target motor horsepower is limited to not exceed the second target motor horsepower so as to control the torque of the electric motors.