DC-to-AC Conversion Apparatus with Reduced Switch Count
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Solution Overview
Problem
Traditional three-phase three-arm inverters in solar photovoltaic power generation systems require numerous switch components and suffer from significant leakage current due to their design.
Innovation Solution
A DC-to-AC conversion apparatus with a reduced number of switches and output inductors, utilizing a configuration with input and output capacitors connected in series to maintain voltage balance, and a control circuit generating phase-to-phase control signals to manage energy storage and release efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a traditional three-phase three-arm inverter is used, then the circuit can convert DC to three-phase AC, but the number of switch components increases and leakage current becomes significant
Solution Approach 1:
The patent extracts and removes one entire bridge arm (phase) from the traditional three-phase three-arm inverter configuration. This reduction from three bridge arms to two bridge arms directly decreases the number of switch components and eliminates the harmful leakage current associated with the traditional design, while still achieving three-phase AC output through the neutral point connection to the first phase sequence.
2Device complexity
If the number of switches and output inductors is reduced, then device complexity decreases, but maintaining voltage balance across capacitors becomes more challenging
Solution Approach 1:
The patent implements a control circuit that generates control signals to manage the switching of bridge arms based on feedback regarding capacitor voltages. This feedback mechanism ensures that the voltage across the capacitors at the DC input side is maintained accurately equal to a half of the DC input voltage, even with the reduced number of switches and output inductors.
Solution Approach 2:
The patent connects the neutral point of the input capacitor assembly to the first phase sequence of the three-phase AC output power source. This equipotential connection strategy helps maintain voltage balance across the capacitors by establishing a reference potential that stabilizes the DC input side voltage distribution.
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 reduces the number of switches and inductors, minimizes leakage current, and maintains accurate voltage balance across capacitors, enhancing the efficiency of DC-to-AC conversion in solar photovoltaic systems.
Implementation Method 1
The input capacitor assembly is connected to the DC input power source and has a neutral point
Implementation Method 2
the control circuit is configured to generate a plurality of control signals to control the first conversion circuit and the second conversion circuit so as to convert the DC input power source into the three-phase AC output power source
Data Source
AI summary
A DC-to-AC conversion apparatus converts a DC input power source to a three-phase AC output power source. The DC-to-AC conversion apparatus includes an input capacitor assembly, a first conversion circuit, a second conversion circuit, and a control circuit. The input capacitor assembly is connected to the DC input power source, and has a neutral point. The neutral point is connected to a first phase sequence of the AC output power source. The first conversion circuit is connected a second phase sequence and a third phase sequence. The second conversion circuit is connected to the first phase sequence, the second phase sequence, and the third phase sequence. The control circuit generates a plurality of control signals to respectively control the first conversion circuit and the second conversion circuit, thus converting the DC input power source into the three-phase AC output power source.