Electric Drive Voltage Management via Torque Limiting and Power Dissipation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In electric drive systems for heavy machinery, voltage fluctuations due to variable loading and changing operating conditions lead to over-voltage and under-voltage issues, which can cause inefficiencies and mechanical stress, necessitating effective management to maintain optimal machine operation.
Innovation Solution
A method and system for voltage supply management in electric drive systems, involving the calculation of a desired voltage value based on current conditions, evaluation of voltage error signals to detect over-voltage or under-voltage conditions, and subsequent power dissipation or torque command limiting to stabilize the voltage supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the drive motors act as generators during retarding, then the voltage generation capability is improved, but the supply voltage increases to unacceptable levels
Solution Approach 1:
The patent converts the harmful over-voltage effect into a beneficial retarding force by controlling the drive motors to operate as generators during retarding. The electrical energy generated is dissipated through resistor grids, transforming the harmful voltage spike into useful kinetic energy recovery while maintaining safe voltage levels through controlled dissipation.
Solution Approach 2:
The patent introduces resistor grids as an intermediary component between the drive motors and the supply link. These resistor grids act as a mediator that absorbs and dissipates the excess electrical energy generated during retarding, preventing direct voltage spikes from reaching the supply link while allowing the energy conversion process to continue.
2Adaptability or versatility
If variable loading and changing operating conditions are accommodated, then the system adaptability is improved, but voltage fluctuations increase
Solution Approach 1:
The patent implements a feedback control system that continuously monitors the supply voltage and adjusts the torque commands to the drive motors accordingly. The controller receives voltage signals from the supply link and modifies the torque commands to maintain voltage within acceptable ranges, creating a closed-loop control mechanism that adapts to varying operating conditions while stabilizing voltage.
Solution Approach 2:
The patent employs dynamic torque command adjustment based on real-time voltage conditions. The controller dynamically modifies the torque commands to the drive motors in response to changing voltage levels, enabling the system to adapt to variable loading and operating conditions while maintaining voltage stability through continuous adjustment of motor torque output.
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 approach effectively manages voltage fluctuations, enhancing the efficiency and reliability of electric drive systems by maintaining a stable voltage supply, reducing mechanical stress, and improving overall machine performance.
Implementation Method 1
an electrical power generator, which provides power to one or more electric drive motors
Implementation Method 2
The motor transforms the electrical power back into mechanical power that drives the wheel
Implementation Method 3
Power is dissipated from the supply link when an over-voltage condition is present
Data Source
AI summary
A method of voltage supply management for an electric drive system includes receiving a voltage signal (1002) indicative of a voltage in a supply link, and one or more condition signals that are indicative of an operating condition of the electric drive system. A difference between a desired voltage value (1008), which is calculated based on the voltage signal (1002) and the one or more condition signals, and the voltage signal (1002) yields a voltage error signal (1014). The voltage error signal (1014) is evaluated to indicate an over-voltage condition or an under-voltage condition. Power is dissipated from the supply link when an over-voltage condition is present and a torque command limit with respect to the one or more electric drive motors (210) is imposed when an under-voltage condition is present.