Bidirectional Insulated DC/DC Converter Using 3-Level Inverters
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Solution Overview
Problem
Bidirectional insulated DC/DC converters with 2-level inverters suffer from harmonic distortion in output AC voltage, leading to efficiency degradation, and existing solutions like series resonance circuits increase device size and generate losses.
Innovation Solution
A bidirectional insulated DC/DC converter using single-phase 3-level inverters and an insulated transformer, where the 3-level inverters generate AC voltages with controlled pulse widths and phase differences to suppress harmonic components, eliminating the need for series resonance circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a series resonance circuit including a reactor and capacitor is connected to the primary winding to suppress harmonic components, then the harmonic component is reduced, but the device size is enlarged and power losses increase
Solution Approach 1:
The patent changes the fundamental parameter of the inverter structure from 2-level to 3-level configuration. This structural parameter change inherently suppresses harmonic components in the output AC voltage without requiring external resonance circuits, thus avoiding device enlargement while maintaining harmonic suppression effectiveness.
2Object-generated harmful factors
If a series resonance circuit including a reactor and capacitor is connected to the primary winding to suppress harmonic components, then the harmonic component is reduced, but power losses increase due to losses in the series resonance circuit
Solution Approach 1:
The patent changes the inverter structure from 2-level to 3-level, which fundamentally alters the voltage waveform characteristics. This parameter change reduces harmonic content at the source, eliminating the need for additional resonance circuits that would introduce power losses, thereby improving overall conversion efficiency.
3Device complexity
If a 2-level inverter is used in the bidirectional insulated DC/DC converter, then the configuration is simpler, but the output AC voltage contains harmonic components causing distortion and efficiency degradation
Solution Approach 1:
The patent transitions from a 2-level inverter structure to a 3-level inverter structure. This parameter change in the inverter configuration inherently produces output AC voltage with reduced harmonic components, improving waveform quality and conversion efficiency without adding complex external harmonic suppression 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
This configuration effectively suppresses harmonic components, reducing power losses and improving conversion efficiency while maintaining a compact design.
Implementation Method 1
The insulated transformer includes a primary winding that receives the first AC voltage from the first and second output terminals and a secondary winding that receives the second AC voltage from the third and fourth output terminals
Data Source
AI summary
A bidirectional insulated DC/DC converter includes a first single-phase 3-level inverter, a second single-phase 3-level inverter, and an insulated transformer. The first single-phase 3-level inverter generates a first AC voltage between output terminals based on a first DC voltage received from a first DC circuit. The second single-phase 3-level inverter generates a second AC voltage between output terminals based on a second DC voltage received from a second DC circuit. The insulated transformer includes a primary winding that receives the first AC voltage from the output terminals and a secondary winding that receives the second AC voltage from the output terminals.