Power Converter Circuit with Switchable Storage Inductor
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Solution Overview
Problem
Conventional inverter and DC/DC converter topologies suffer from poor efficiency over the entire operating range due to hard switching of power semiconductors, leading to issues like insulation degradation in motor windings and the need for complex filters to eliminate harmonics, and they often have floating grounds that result in undesired displacement currents.
Innovation Solution
A power converter circuit with a storage inductor and four power switches, where the storage choke can be connected and bypassed switchably, and a controller that modulates phase shift and switching frequency to achieve ZVS-relieved operation, minimizing losses and avoiding major voltage changes and harmonics, ensuring no floating ground.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional inverter topologies (full-bridge or half-bridge) are used, then the circuit structure is simple and well-established, but the efficiency is poor over the entire working range due to hard switching of power semiconductors
Solution Approach 1:
The circuit is segmented into multiple switching paths with four power switches (S1-S4) arranged in a bridge configuration, allowing selective activation of different paths to achieve soft switching conditions while maintaining a relatively simple overall structure
Solution Approach 2:
The circuit employs dynamic switching control where the switching paths and frequency are adjusted based on operating conditions. The storage inductor L is switchably connected or bypassed to dynamically optimize the switching characteristics and maintain high efficiency across different operating points
2Loss of energy
If hard switching is used in conventional inverters, then the control is simple, but the efficiency is severely limited and voltage jumps occur between discrete levels
Solution Approach 1:
The circuit uses periodic switching control with variable frequency and duty cycle modulation. The switching paths are activated in periodic sequences that create soft switching conditions, reducing switching losses while the controller manages the periodic activation patterns
Solution Approach 2:
The controller varies switching frequency and duty cycle parameters dynamically to maintain optimal operating conditions. By changing these parameters, the circuit achieves soft switching across different load conditions while managing control complexity through parameter optimization
3Object-affected harmful factors
If conventional inverter topologies are used, then the circuit is simpler, but large voltage changes occur that degrade motor winding insulation and require complex output filters
Solution Approach 1:
The storage inductor L is positioned beforehand in the circuit path to cushion and limit voltage changes. By being switchably connected in series with the load, it provides inherent protection against voltage spikes before they can damage insulation, reducing the need for additional filtering components
4Object-affected harmful factors
If floating ground is used in single-phase inverters, then the grounding is simpler, but parasitic capacitances cause undesired displacement currents
Solution Approach 1:
The circuit merges both grounds (input ground and output ground) into a single reference potential point. This consolidation eliminates the floating ground configuration and its associated parasitic capacitances, preventing displacement currents while maintaining a simple single-point grounding structure
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 achieves high overall efficiency, reduces losses in switches, storage choke, and capacitors, and eliminates the need for complex filters, providing a stable and efficient power conversion without significant voltage changes or harmonics.
Implementation Method 1
a storage inductor and at least four power switches, wherein the storage choke can be connected and bypassed switchably
Implementation Method 2
at least four power switches, wherein the storage choke can be connected and bypassed switchably
Implementation Method 3
a controller that modulates phase shift and switching frequency to achieve ZVS-relieved operation
Data Source
Figure 1a~1c
Figure 1d
Figure 1e
AI summary
A power converter circuit comprises a voltage input, a voltage output, and a storage inductor. The power converter circuit additionally comprises at least four power switches, wherein a first power switch of the four power switches couples a second potential tap of the voltage input to the storage inductor in a switchable manner, and a fourth power switch of the power switches couples the second potential tap of the voltage output to the storage inductor in a switchable manner. The third power switch of the four power switches couples the second potential tap of the voltage input or of the voltage output to a first side of the storage inductor in a switchable manner while the second power switch of the four power switches couples the first potential tap of the voltage input and the voltage output to a second side of the storage inductor in a switchable manner.