Battery Control Method for Stabilizing Inverter Voltage
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Solution Overview
Problem
In electric vehicle battery packs, the varying output voltage due to charging and discharging currents leads to unstable operation of inverters, necessitating a method to maintain a constant voltage supply.
Innovation Solution
A processor-implemented battery control method calculates a boosting ratio based on measured voltage values and preset voltage, transmitting this ratio to converters to boost output voltages, ensuring the sum remains constant, even with changes in battery states or abnormal batteries being bypassed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the battery pack supplies power to the inverter with varying output voltage based on charging and discharging current, then the battery can operate flexibly with changing load demands, but the inverter cannot operate stably
Solution Approach 1:
A DC/DC converter is introduced as an intermediary device between the battery pack and the inverter. The converter receives varying voltage from the battery and converts it to a stable voltage for the inverter, thereby decoupling the battery's flexible operation from the inverter's stability requirement
Solution Approach 2:
The DC/DC converter dynamically adjusts its conversion ratio parameter based on the battery voltage and load conditions, transforming the varying battery output voltage into a constant voltage suitable for stable inverter operation
2Power
If multiple batteries are connected in series to increase output voltage, then the voltage supply to the inverter can be increased, but the sum of voltages varies with battery state changes causing instability
Solution Approach 1:
The control unit continuously monitors the actual output voltage of the battery pack and adjusts the DC/DC converter's operation in real-time based on this feedback, ensuring the converted voltage remains stable despite variations in battery state
Solution Approach 2:
The DC/DC converter operates dynamically by continuously adjusting its conversion characteristics in response to changing battery conditions, transforming the static series connection of batteries into a dynamically stabilized voltage source
3Reliability
If the output voltage of each battery is boosted individually, then the total voltage can be maintained constant, but additional converters and control complexity are required
Solution Approach 1:
Multiple battery strings connected in series are merged into a single unified output through one DC/DC converter, simplifying the system architecture while maintaining voltage stability, rather than using separate converters for each battery
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 stabilizes the inverter operation by maintaining a constant voltage supply to the load, regardless of battery state changes or abnormalities, enhancing the reliability of electric vehicle systems.
Implementation Method 1
The converters are configured to boost output voltages of the batteries based on the calculated boosting ratio
Data Source
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AI summary
A battery control method that calculates a boosting ratio for converters based on voltage values of batteries and a preset voltage value, and transmits the calculated boosting ratio to the converters is disclosed. The converters are configured to boost output voltages of the batteries based on the calculated boosting ratio, and a sum of the boosted output voltages is equal to the preset voltage value.