Matrix Converter Battery Charger Using Opposed MOSFET Body Diodes
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Solution Overview
Problem
Existing vehicle battery chargers are not optimized for bidirectional current flow, leading to inefficiencies when MOSFET switches are non-conductive.
Innovation Solution
A stationary vehicle battery charger utilizing a matrix converter configuration with MOSFET modules, where each MOSFET switch includes a body diode, allowing bidirectional current flow while conductive, and preventing it when non-conductive through opposing body diodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MOSFET switches are used without optimized body diode configuration, then the charger can handle bidirectional current flow when MOSFETs are conductive, but current flow cannot be properly prevented when MOSFETs are non-conductive
Solution Approach 1:
The patent applies asymmetry by configuring body diodes in opposite directions in different MOSFET modules. This asymmetric arrangement allows current to flow bidirectionally when MOSFETs are conductive while preventing reverse current flow when MOSFETs are non-conductive, resolving the contradiction between reliable current control and energy efficiency.
Solution Approach 2:
The patent converts the potentially harmful effect of body diodes (which can allow unwanted reverse current) into a beneficial feature. By strategically orienting body diodes in opposite directions, the invention uses the diodes' inherent property to block reverse current as a mechanism for achieving precise current control, turning what could be a source of energy loss into a tool for improving reliability and efficiency.
2Device complexity
If standard MOSFET modules are used in matrix converter, then device complexity is reduced, but control precision over bidirectional current flow is insufficient
Solution Approach 1:
The patent applies local quality by making specific modifications to the MOSFET module configuration - specifically, orienting body diodes in opposite directions in different modules. This localized change to the module arrangement maintains overall device simplicity while achieving precise control over bidirectional current flow, resolving the contradiction between low complexity and high control precision.
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 effectively prevents bidirectional current flow when MOSFET switches are non-conductive, enhancing the efficiency and control of electrical current in vehicle battery chargers.
Implementation Method 1
each MOSFET switch including a body diode and capable of bidirectional electrical current flow while the MOSFET switch is conductive, such that a MOSFET switch from a first MOSFET module and a MOSFET switch from a second, different MOSFET module are electrically coupled so that the body diodes prevent bidirectional current flow while the MOSFET switch from the first MOSFET module and the MOSFET from the second, different MOSFET module are non-conductive
Data Source
AI summary
A stationary vehicle battery charger for charging vehicle batteries in battery electric vehicles (BEVs) includes a plurality of MOSFET modules, electrically connected to form a matrix converter, comprising a plurality of MOSFET switches, each MOSFET switch including a body diode and capable of bidirectional electrical current flow while the MOSFET switch is conductive, such that a MOSFET switch from a first MOSFET module and a MOSFET switch from a second, different MOSFET module are electrically coupled so that the body diodes prevent bidirectional current flow while the MOSFET switch from the first MOSFET module and the MOSFET switch from the second, different MOSFET module are non-conductive.