Electric Vehicle Controller Loss Minimization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electric vehicle controllers prioritize reducing switching loss, leading to inefficient AC motor operation and increased switching loss in three-pulse modes, while maintaining constant voltage independent of the AC motor's load state, which limits overall efficiency.
Innovation Solution
An electric vehicle controller that calculates and selects magnetic-flux command values based on torque commands to minimize total losses in both the AC motor and main circuit, using a vector-control-command-value calculating unit to output optimal magnetic-flux command values to the vector control unit, allowing for efficient power conversion and reduced switching losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If one-pulse mode is used to reduce switching loss, then switching loss of main circuit is reduced, but AC motor efficiency is reduced due to constant fixed voltage application
Solution Approach 1:
The patent applies dynamics by transitioning from a static one-pulse mode with fixed voltage to a dynamic control system that adjusts voltage amplitude based on operating conditions. The vector control unit dynamically modifies the voltage command values according to the AC motor's actual load state, enabling the system to adapt between minimizing switching loss and maximizing motor efficiency depending on the operational context.
Solution Approach 2:
The patent changes the voltage amplitude parameter dynamically based on operating conditions. Instead of maintaining a constant fixed voltage in one-pulse mode, the system adjusts the voltage command values according to the AC motor's load state, allowing optimization of both switching loss and motor efficiency through parameter adaptation.
2Use of energy by moving object
If three-pulse mode is used to optimize AC motor efficiency, then AC motor efficiency is improved, but switching loss of main circuit increases
Solution Approach 1:
The system dynamically selects between one-pulse mode and three-pulse mode based on real-time operating conditions and AC motor load state. This dynamic mode selection allows the system to use three-pulse mode when motor efficiency is prioritized while accepting higher switching loss, and switch to one-pulse mode when switching loss reduction is more critical.
Solution Approach 2:
The control system periodically evaluates operating conditions and switches between one-pulse and three-pulse modes as needed. This periodic assessment and mode switching enables the system to optimize the trade-off between switching loss and motor efficiency based on changing load 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
This approach improves the efficiency of the entire electric vehicle controller by minimizing total losses and optimizing power conversion, enabling efficient operation across varying load states without increasing the dimension, weight, or cost of the main circuit.
Implementation Method 1
a main circuit configured to convert a DC power supplied from a DC power source into an AC power and supply the AC power to the AC motor
Implementation Method 2
an AC motor; a vector control unit configured to generate a switching command to instruct a switching operation of the main circuit, thereby performing vector control of the AC motor
Data Source
AI summary
An object is to obtain an electric vehicle controller capable of reducing a total sum of losses of an AD motor and losses of a main circuit. In a vector-control-command-value calculating unit, according to a torque command T*, a DC-voltage command value EFCR and a magnetic-flux command value F2R for which a total sum of losses of an AD motor and losses of a second main circuit is minimized is calculated and selected. The vector-control-command-value calculating unit outputs the magnetic-flux command value F2R to a vector control unit, and outputs the DC-voltage command value EFCR to a converter control unit.