Vienna Rectifier Charging Control Reducing Capacitor Bulk
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Solution Overview
Problem
Existing single-phase charging devices require a large number of capacitors to manage current fluctuations, leading to increased costs and bulk due to restrictive low-frequency components, which is not optimal for capacitive technologies.
Innovation Solution
A method for controlling a battery-charging device using a three-phase Vienna rectifier with pulse width modulation control signals, where the DC-DC converter stage regulates intermediate voltages, allowing for reduced capacitor values by managing current fluctuations at the input, and utilizing LLC resonant converters to maintain a fixed voltage on power supply buses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large number of capacitors are used to manage current fluctuations in single-phase charging devices, then current regulation stability is improved, but device bulk and cost increase
Solution Approach 1:
The patent segments the charging device into two independent control stages: a PFC rectifier stage and a DC-DC converter stage. Each stage has independent control loops that regulate different parameters (input current shape and intermediate bus voltages respectively). This segmentation allows for more efficient current management with reduced capacitor requirements compared to traditional single-stage designs.
Solution Approach 2:
The patent changes the control parameters by introducing independent voltage regulation on the intermediate DC buses. Instead of using large capacitors to stabilize current directly, the system regulates the intermediate voltages through the DC-DC converter stage, which indirectly stabilizes the current with much smaller capacitor values.
2Reliability
If a large number of capacitors are used to manage current fluctuations in single-phase charging devices, then current regulation stability is improved, but manufacturing cost increases
Solution Approach 1:
The patent segments the charging device into two independent control stages: a PFC rectifier stage and a DC-DC converter stage. Each stage has independent control loops that regulate different parameters (input current shape and intermediate bus voltages respectively). This segmentation allows for more efficient current management with reduced capacitor requirements compared to traditional single-stage designs.
Solution Approach 2:
The patent changes the control parameters by introducing independent voltage regulation on the intermediate DC buses. Instead of using large capacitors to stabilize current directly, the system regulates the intermediate voltages through the DC-DC converter stage, which indirectly stabilizes the current with much smaller capacitor values.
3Volume of stationary object
If intermediate voltage regulation is implemented using DC-DC converter stage, then capacitor values can be reduced, but control complexity increases
Solution Approach 1:
The patent segments the charging device into two independent control stages: a PFC rectifier stage and a DC-DC converter stage. Each stage has independent control loops that regulate different parameters (input current shape and intermediate bus voltages respectively). This segmentation allows for more efficient current management with reduced capacitor requirements compared to traditional single-stage designs.
Solution Approach 2:
The patent introduces an intermediary control mechanism by regulating the intermediate DC bus voltages through the DC-DC converter stage. This intermediary voltage regulation acts as a mediator between the PFC stage and the battery charging stage, enabling compact capacitor design while maintaining system stability through controlled intermediate parameters.
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 reduces the number of capacitors needed, minimizing costs and bulk while maintaining efficient power regulation, especially in single-phase charging modes, by decoupling the PFC and DC-DC converter stages effectively.
Implementation Method 1
a first AC-DC converter stage, which includes a power factor correction (PFC) circuit 11 in order to limit the input current harmonics
Implementation Method 2
a second DC-DC (direct current-direct current) converter 12 stage, to regulate the charge and also to perform the insulating function for usage safety
Implementation Method 3
at the output, in series, to a resonant circuit L, C and to the primary of a transformer T
Data Source
AI summary
A method controls a battery-charging device including a rectifier stage of three-phase Vienna rectifier type capable of being connected to a single-phase or three-phase electrical power supply grid and linked by first and second DC power supply buses to a DC-to-DC converter stage including first and second LLC resonant converters that are connected to first and second DC power supply bus capacitors, respectively, which are positioned on each of the buses at the output of the rectifier stage. The power supply for the charging device is single phase and the voltage of the first and second DC power supply bus capacitors is regulated independently by the first and second LLC resonant converters so as to provide a fixed regulated voltage on each of the DC power supply buses.