Cascaded Half-Bridge Converter With Phase-Staggered Switching
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Solution Overview
Problem
Existing DC-DC and AC-DC converters face challenges in achieving compact and cost-effective designs for high power, voltage, and current levels, due to the need for higher voltage-rated semiconductor switches and larger magnetic components.
Innovation Solution
The use of multi-phase converter implementations with multiple half bridges stacked on a single leg to generate multi-phase voltages, along with control circuitry that operates the switches in a phase-staggered manner, allows for higher frequency operation and increased power density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If higher voltage-rated semiconductor switches are used to accommodate higher operating voltages, then the system can handle higher power and voltage levels, but the system cost and size increase due to larger magnetic components and slower switching performance
Solution Approach 1:
The patent divides the high-voltage power conversion task into multiple lower-voltage stages using cascaded half-bridge modules. Each half-bridge operates at a fraction of the total system voltage, allowing the use of lower voltage-rated switches with faster switching performance and smaller magnetic components, thereby reducing overall system size and cost while maintaining high power handling capability.
2Power
If higher voltage-rated semiconductor switches are used, then the system can operate at higher voltages, but the switching frequency decreases due to slower switch performance
Solution Approach 1:
By segmenting the voltage handling across multiple cascaded half-bridge stages, each switch operates at lower voltage stress and can switch faster. The multi-phase staggered control further enables higher effective switching frequency by distributing the power conversion across parallel phases.
Solution Approach 2:
The patent employs multi-phase staggered control where the switching phases are time-displaced from each other. This dynamic control strategy allows the system to maintain continuous power transfer at higher effective frequencies while each individual switch operates within its optimal switching speed range.
3Power
If multi-phase implementations are used to increase power density, then the system can handle higher power levels, but the device complexity increases
Solution Approach 1:
The patent combines multiple half-bridge modules in a cascaded configuration sharing common DC link capacitors and control infrastructure. This merging approach achieves multi-phase power conversion with higher power density while reducing the number of discrete components compared to traditional multi-phase designs, thereby managing device complexity.
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 approach enables the design of compact and cost-effective switching converters that can handle higher power, voltage, and current levels while maintaining high frequency operation, thus improving power density and reducing system size and cost.
Implementation Method 1
a transformer with a plurality of primary windings and a plurality of secondary windings
Implementation Method 2
Each half bridge can include an input capacitor; upper and lower switches coupled across the input capacitor
Implementation Method 3
a DC blocking capacitor coupled between the switch node and a primary winding terminal of the transformer
Data Source
AI summary
An isolated switching converter can include an inverting bridge, a transformer, a rectifying bridge, and control circuitry. The inverting bridge can receive an input voltage and deliver an output voltage to the transformer primary windings. The inverting bridge can include a plurality of half bridges cascaded across the input voltage. Each half bridge can include an input capacitor; upper and lower switches coupled across the input capacitor and connected at a switch node; and a DC blocking capacitor coupled between the switch node and a primary winding terminal. The rectifying bridge can have an input coupled to the secondary windings of the transformer and can deliver an output voltage of the isolated switching converter. The control circuitry can monitor inverter feedback signal(s) and generate phase staggered inverter drive signal(s). The control circuitry can also monitor rectifier feedback signal(s) and generate rectifier drive signals that operate the rectifying bridge.