Induction Motor Pulsed Current Control for Low-Loss EV Torque
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Solution Overview
Problem
Existing electric vehicles face range anxiety due to limited charging capacity, and increasing energy storage capacity leads to increased vehicle mass and decreased efficiency, necessitating a method to enhance vehicle range without enlarging the energy storage device.
Innovation Solution
A pulsed D-axis and Q-axis command signal approach is employed to operate induction electric machines, where the D-axis and Q-axis current commands are phase-shifted and adjusted based on magnetic flux to reduce noise and vibration, leveraging residual magnetic flux for torque generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the size of the electric energy storage device is increased to increase vehicle range, then the charge storage capacity is improved, but the vehicle mass increases and vehicle efficiency decreases
Solution Approach 1:
The patent applies periodic pulsed operation to the induction electric machine, where current is supplied in discrete pulses rather than continuously. This allows the machine to generate the same average torque with reduced RMS current, lowering I²R losses in the windings and improving overall efficiency. The pulsed operation enables better utilization of the existing energy storage capacity without requiring additional battery capacity.
Solution Approach 2:
The patent changes the operational parameters of the induction electric machine by implementing variable frequency and variable amplitude pulsed current supply. By dynamically adjusting the pulse width, frequency, and duty cycle based on vehicle conditions, the system optimizes torque generation efficiency and reduces energy losses, allowing extended range from the existing energy storage capacity.
2Loss of energy
If pulsed current is supplied to the induction electric machine to reduce losses, then energy efficiency is improved, but torque ripple and noise increase
Solution Approach 1:
The patent implements dynamic adjustment of pulse parameters including frequency, amplitude, and duty cycle based on real-time vehicle conditions such as speed, load, and acceleration requirements. This dynamic control allows the system to optimize the balance between efficiency and smoothness, reducing torque ripple and associated noise while maintaining energy savings from pulsed operation.
Solution Approach 2:
The patent uses overlapping pulsed current sequences with carefully selected timing and duration to ensure continuous torque production. By coordinating multiple phase windings with staggered pulses, the system maintains smooth rotational motion and minimizes torque ripple, thereby reducing noise and vibration while preserving the energy efficiency benefits of pulsed operation.
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 method reduces electric drive system losses, smooths torque generation, and decreases vehicle noise and vibration while maintaining efficiency, thereby extending the vehicle's range on a single charge.
Implementation Method 1
supplying a pulsed magnetic flux current command signal and a pulsed torque current command signal to an electric machine controller... operating an electric machine via the pulsed magnetic flux current command signal and the pulsed torque current command signal
Data Source
AI summary
Systems and methods for commanding an electric drive system for an electric or hybrid vehicle are described. In one example, the drive system is commanded by a controller that supplies different D-axis and Q axis command signals. The different D-axis and Q-axis command signals permit adjustments to alter vehicle noise and vibration levels.