On-Board EV Charger Harmonic Shaping for Fast Battery Charging
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Solution Overview
Problem
Existing electric vehicle charging systems are inefficient and can damage batteries due to high current fast charging, which limits charging speed and reduces battery life.
Innovation Solution
A system and method for shaping the charge signal based on harmonic analysis to minimize impedance and optimize charging efficiency, using a charge signal shaping circuit that adjusts the charge signal received from a charging station to correspond with harmonics associated with lower battery impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high current fast charging is used, then charging speed is improved, but battery damage increases and battery life decreases
Solution Approach 1:
The patent applies periodic pulsed charging instead of continuous high current charging. The system delivers charging current in controlled pulses with specific duty cycles and frequencies, allowing the battery to recover between pulses while maintaining high average charging power. This periodic action enables fast charging without the continuous stress that damages battery life.
Solution Approach 2:
The patent dynamically adjusts charging parameters including current magnitude, pulse width, duty cycle, and frequency based on real-time battery state monitoring. The system continuously adapts the charging waveform to match optimal impedance characteristics at different charge levels, enabling high-speed charging while preventing damage through real-time parameter optimization.
2Loss of time
If high current fast charging is used, then charging time is reduced, but energy loss and heat generation increase
Solution Approach 1:
The pulsed charging waveform creates periodic intervals where current flows and where it rests. During the off-periods, the battery's internal impedance decreases and thermal management improves, reducing energy loss. The periodic nature allows the system to maintain high average power transfer while minimizing peak energy losses that occur in continuous charging.
Solution Approach 2:
The system performs preliminary characterization of battery impedance across different frequencies and charge states before and during charging. This preliminary knowledge allows the controller to pre-select optimal pulse parameters that minimize energy loss for the current battery state, preventing excessive heat generation and energy waste before they occur.
3Device complexity
If conventional charging signals are used, then charging process is simple, but charging efficiency is limited by battery impedance
Solution Approach 1:
The patent fundamentally changes the parameter space of charging signals by introducing frequency and duty cycle as controllable variables in addition to current magnitude. By sweeping through different frequencies to identify optimal impedance matching points and adjusting duty cycles to control average power, the system achieves superior charging efficiency while maintaining manageable complexity through systematic parameter optimization.
Solution Approach 2:
The system continuously monitors battery voltage, current, and temperature, and uses this feedback to dynamically adjust the pulse width modulation (PWM) parameters of the charging signal. The feedback loop identifies the frequency and duty cycle that maximize charging efficiency at each moment, allowing the system to adapt to changing battery conditions while maintaining high efficiency throughout the charging process.
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 enables faster, more efficient charging while reducing battery damage and extending battery life by optimizing charge rates and minimizing energy loss.
Implementation Method 1
A system and method for shaping the charge signal based on harmonic analysis to minimize impedance and optimize charging efficiency
Data Source
AI summary
Systems, circuits, and methods are disclosed herein for charging (recharging) one or more batteries of an electric vehicle through an on-board charge shaping (or tuning) circuit. The charge shaping circuit may alter the charge signal received from a charging station and/or a regenerative charge signal from the vehicle motor based on one or more charge conditions at the battery. The charge shaping circuit and/or a motor controller/inverter of the electric vehicle may include circuitry that is controllable to generate a shaped power signal in a similar manner as above, with or without the charge shaping circuit discussed above. In some implementations, one or more heat transfer systems may be included to transfer heat generated from the battery charging system to the battery.