Modular Current Source Element for High-Voltage Power Conversion
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Solution Overview
Problem
High-frequency switching in power conversion equipment for high voltages leads to excessive converter losses and insulation stress, limiting performance due to large self-inductance and poor semiconductor switch operation.
Innovation Solution
A current source element with a chain of modules, each containing semiconductor switches and capacitors, allows for efficient power conversion by controlling the switching within individual modules, minimizing self-inductance and maintaining capacitor charge, enabling efficient power transfer between input and output circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If high frequency switching is used to reduce passive component size, then converter compactness is improved, but converter losses increase and insulation stress increases
Solution Approach 1:
The converter is divided into multiple independent modules, each with its own semiconductor switches and circulating current path. This segmentation allows each module to operate at lower switching frequencies while the overall converter achieves high power density, resolving the contradiction between compactness and losses.
Solution Approach 2:
The invention transitions from single-phase high-frequency switching to multi-phase modular architecture, effectively adding temporal and spatial dimensions to the switching operation. This allows power conversion without requiring extremely high switching frequencies in each individual module.
2Volume of moving object
If high frequency switching is used to reduce passive component size, then converter compactness is improved, but insulation stress increases
Solution Approach 1:
By segmenting the converter into multiple modules with independent circulating current paths, the voltage stress on insulation in each module is reduced compared to a single high-voltage switch. Each module handles a portion of the total voltage, reducing insulation requirements.
3Stress or pressure
If large area current path is used to maintain insulation, then insulation is maintained, but self-inductance increases and converter performance is limited
Solution Approach 1:
The current path is segmented into multiple parallel paths through the modular architecture. Each module has its own circulating current path that can be optimized for low inductance, while the overall system maintains proper insulation through the modular structure.
Solution Approach 2:
The modular structure acts as an intermediary between the requirements for large insulation area and small inductance. Each module can have compact low-inductance current paths while the modular arrangement maintains necessary insulation distances.
4Reliability
If series semiconductor switches are configured to operate within operating parameters of the poorest switch, then reliability is improved, but converter losses become exaggerated
Solution Approach 1:
Instead of using series switches where the poorest switch limits the entire system, the invention segments the converter into parallel modules. Each module's switches operate independently within their own optimized parameters, allowing each module to be designed for maximum efficiency rather than being constrained by the weakest component.
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 reduces converter losses, minimizes component size, and enhances efficiency by containing switching operations within modules, allowing for compact and cost-effective high-voltage power conversion.
Implementation Method 1
each include charged capacitance that can be switched in and out of circuit
Implementation Method 2
employ switches based on semiconductor technology that direct current
Implementation Method 3
an inductor L connected in series between the voltage terminals
Data Source
Figure 1
Figure 2~5
Figure 6~7
AI summary
A current source element (10) for a current source converter comprises first and second voltage terminals (V1, V2). The current source element (10) also comprises a chain of modules (M1, M2, M3....MN) and an inductor (L) connected in series between the voltage terminals (V1, V2). Each module (M1, M2, M3....MN) includes at least one pair of semiconductor switches (12, 14) connected in parallel with a capacitor (20). The semiconductor switches (12, 14) are controllable in use to provide a continuously variable voltage source to directly control the rate of change of current in the inductor (L).