Vienna Rectifier Charging Module With Midpoint Inductor PFC
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Solution Overview
Problem
Conventional three-phase Vienna rectifier topologies for charging systems face high costs and complexity in implementing bidirectional power flow with distorted current waveforms and require additional reactive apparatus for power factor correction.
Innovation Solution
Incorporating an inductor between the bus midpoint and the three-phase rectifier module in the Vienna topology, which absorbs reactive power and isolates the rectifier module from the bus capacitor, optimizing current waveforms and reducing hardware costs by achieving variable power factor performance comparable to bidirectional flow topologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a diode in the Vienna topology is replaced with a power switch transistor to implement bidirectional power flow, then bidirectional power flow capability is achieved, but hardware costs increase
Solution Approach 1:
The patent segments the power factor correction function from the main rectifier circuit by adding a separate auxiliary circuit consisting of an auxiliary switch and inductor. This auxiliary circuit handles reactive power compensation independently, allowing the main Vienna rectifier to maintain its simple unidirectional topology while achieving variable power factor control through coordinated operation of the auxiliary components.
Solution Approach 2:
The patent introduces an auxiliary switch and inductor as intermediary components that mediate between the rectifier circuit and the power factor correction function. These intermediary elements enable reactive power management without requiring replacement of the main rectifier diodes with expensive power switch transistors, thus achieving bidirectional power flow capability at lower cost.
2Reliability
If compensation range is determined based on input voltage angle and common-mode signal is generated to change phase difference, then power factor correction is achieved, but implementation complexity increases and current waveform becomes distorted
Solution Approach 1:
The patent extracts the power factor correction function from the complex voltage-angle-based control scheme and implements it through a simpler auxiliary circuit with dedicated reactive power compensation components. This separate auxiliary circuit handles phase difference adjustment independently, reducing the complexity of the main rectifier control while improving current waveform quality.
Solution Approach 2:
The patent implements dynamic power factor control by enabling the auxiliary switch to operate in different states (on, off, or PWM modulation) based on real-time power factor requirements. This dynamic operation allows the system to adaptively adjust the compensation range and phase difference without complex control algorithms, maintaining simple implementation while achieving reliable power factor correction.
3Object-generated harmful factors
If an inductor is added between bus midpoint and three-phase rectifier module, then reactive power is absorbed and current waveform is improved, but device complexity increases
Solution Approach 1:
The patent merges the reactive power compensation function with the existing bus capacitor structure by adding the inductor and auxiliary switch in parallel with the bus capacitor. This combined configuration allows the same circuit elements to serve dual purposes: the bus capacitor handles active power filtering while the added inductor and auxiliary switch handle reactive power compensation, reducing overall system complexity compared to separate compensation circuits.
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
The solution improves bus ripple and current waveforms in non-unity power factor conditions while reducing hardware costs, achieving performance comparable to bidirectional power flow topologies.
Implementation Method 1
an inductor is added between a bus midpoint and a three-phase rectifier module in Vienna topology. Because there is no sudden change in a current through an inductor, and the inductor may absorb a part of reactive power and isolate the rectifier module from a bus capacitor
Data Source
AI summary
A charging module and a charging device. The charging module includes a three-phase rectifier module, a bus capacitor module, an inductor, and a controller. An input end of the three-phase rectifier module is electrically connected to an input power supply, and an output end of the three-phase rectifier module is electrically connected to an input end of the bus capacitor module. The bus capacitor module includes a first bus capacitor and a second bus capacitor. The first bus capacitor is connected between a first output end of a three-phase bridge arm and a midpoint of the three-phase bridge arm, and the second bus capacitor is electrically connected between a second output end of the three-phase bridge arm and the midpoint. The inductor is electrically connected to the midpoint of the three-phase bridge arm and a midpoint between the first bus capacitor and the second bus capacitor.