Dynamic PFC Converter Voltage Control for EV Charging
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Solution Overview
Problem
Conventional charging control methods for plug-in hybrid electric vehicles and electric vehicles struggle to achieve high efficiency across a wide voltage range, leading to reduced average charging efficiency, increased charging time, and deteriorated fuel consumption rates due to fixed output voltage control of power factor correction converters.
Innovation Solution
A charging control method that dynamically adjusts the output voltage of the power factor correction converter based on sensed battery and AC input voltages, using a controller to calculate a target voltage and maintain it within optimal ranges, ensuring efficient power transmission and avoiding areas where unit power factor control is impossible.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the output voltage of the PFC converter is controlled to be fixed, then the power factor is compensated, but the charging efficiency deteriorates in wide battery voltage range
Solution Approach 1:
The patent applies dynamics by transitioning from fixed voltage control to dynamic voltage control. The PFC converter output voltage is no longer fixed but dynamically adjusted based on the battery voltage and DC-DC converter duty cycle. This allows the system to adapt to varying battery voltage conditions throughout charging, maintaining high efficiency across the entire voltage range while preserving power factor compensation capability.
Solution Approach 2:
The patent implements parameter changes by modifying the control parameter of the PFC converter output voltage from a constant fixed value to a variable parameter. The output voltage is now determined by calculating a target value based on the battery voltage and the maximum duty cycle of the DC-DC converter, allowing the system to optimize charging efficiency at different operating points while maintaining reliable power factor compensation.
2Device complexity
If the output voltage of the PFC converter is fixed, then the control is simple, but the charging time increases
Solution Approach 1:
The patent applies dynamics by implementing dynamic voltage control that adapts to changing battery conditions. The controller continuously adjusts the PFC converter output voltage based on real-time battery voltage and DC-DC converter duty cycle measurements, enabling faster charging across the entire voltage range while maintaining manageable control complexity through systematic calculation of target voltage values.
Solution Approach 2:
The patent implements feedback by using the battery voltage and DC-DC converter duty cycle as feedback signals to adjust the PFC converter output voltage. The controller calculates the target voltage based on these feedback parameters, creating a closed-loop control system that optimizes charging speed while keeping control complexity reasonable through algorithmic determination of control parameters.
3Stability of the object's composition
If the output voltage of the PFC converter is fixed, then the system is stable, but the fuel consumption rate deteriorates
Solution Approach 1:
The patent applies dynamics by transitioning from static fixed voltage control to dynamic voltage control that responds to battery conditions. The PFC converter output voltage is dynamically adjusted based on battery voltage and DC-DC converter duty cycle, enabling the system to maintain optimal efficiency across varying operating conditions, thereby improving fuel consumption rate while preserving system stability through controlled adaptation.
Solution Approach 2:
The patent implements parameter changes by modifying the PFC converter output voltage from a fixed parameter to a dynamically changed parameter. The target voltage is calculated based on battery voltage and duty cycle, allowing the system to optimize energy efficiency and fuel consumption across the entire charging voltage range while maintaining stability through systematic parameter adjustment.
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 enhances charging efficiency and reduces charging time by maintaining optimal voltage control across the entire voltage range, thereby improving the fuel consumption rate and overall charging performance.
Implementation Method 1
a power factor correction (PFC) converter connected to an AC power source to convert an AC input voltage into a DC voltage and compensate for the power factor of the voltage
Implementation Method 2
a DC-DC converter that converts the DC voltage output from the PFC converter
Implementation Method 3
sensing, by a voltage detector, a battery voltage during charging
Data Source
AI summary
A charging control method and system for an environmentally friendly vehicle are provided and promote the enhancement of charging efficiency by improving a power control method of a power factor correction (PFC) converter while a battery is being charged through an on board charger (OBC) in vehicle. The method sensing, by a voltage detector, a battery voltage during charging and calculating, by a controller, a target value to maintain an output voltage of the PFC converter. The target value is calculated from the sensed battery voltage and the maximum available duty value of the DC-DC converter. The output voltage of the PFC converter is maintained, based on the calculated target value.