Modular Nanosecond Pulser Circuit for Fast High-Voltage Rise Times
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Solution Overview
Problem
Current high voltage nanosecond pulsers face challenges in achieving high peak voltage, high peak power, and short pulse widths with fast rise times and low stray inductance and capacitance, which limits their efficiency and versatility in applications such as radar transmitters.
Innovation Solution
A nanosecond pulser design incorporating multiple switch modules with snubber resistors, capacitors, and diodes, coupled with a transformer having a toroid core and low stray inductance and capacitance, allowing for high voltage and power output with variable pulse widths and frequencies, using solid state switches like IGBTs, FETs, and SiC junction transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If solid state switching devices are used to generate high voltage pulses, then peak voltage and peak power are improved, but stray inductance increases causing slower rise times
Solution Approach 1:
The system divides the switching function into multiple parallel solid state switching devices (e.g., multiple IGBTs or MOSFETs) that operate simultaneously. This segmentation allows the current to be distributed across multiple devices, reducing the inductance per device while maintaining high total current capability, thus achieving both high peak power and fast rise times.
Solution Approach 2:
Multiple primary windings from separate switching devices are combined in parallel on the transformer primary side. This merging approach reduces the total stray inductance by providing multiple current paths, enabling the system to deliver high peak power with fast rise times that would be impossible with a single switching device.
2Duration of action of moving object
If pulse width is reduced to achieve shorter durations, then pulse width parameter is improved, but energy delivery capability deteriorates
Solution Approach 1:
The pulser system is designed to provide variable pulse widths through electronic control while maintaining the capability to deliver high energy. The same hardware platform can generate both short high-power pulses and longer energy-delivering pulses by adjusting the switching duration and capacitor discharge parameters, making the system universally applicable to different energy delivery requirements.
3Power
If multiple switch modules are used to increase power output, then peak power is improved, but device complexity increases
Solution Approach 1:
The system uses multiple identical or standardized switch modules that can be independently designed and tested. Each module is a self-contained unit with its own switching device, snubber circuit, and connections to the transformer. This modular segmentation simplifies the overall design process, as each module can be optimized independently and then combined to achieve the desired total power output.
Solution Approach 2:
Multiple switch modules are merged in parallel with standardized interconnections to the transformer primary windings. The snubber circuits are configured in a unified manner across all modules, reducing the variety of circuit configurations needed. This merging approach with standardization reduces the effective complexity while scaling up the power capability.
4Speed
If rise time is reduced for faster pulses, then speed parameter is improved, but voltage spikes and electromagnetic interference increase
Solution Approach 1:
Snubber circuits are pre-configured across all switching devices to provide voltage spike suppression and electromagnetic interference filtering. These RC or RCD snubber networks are designed to activate during the fast switching transitions, cushioning the voltage spikes that inevitably occur during rapid rise times. The snubbers are built into the basic module design, providing automatic protection without requiring additional active control.
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 design enables the generation of electrical pulses with peak voltages over 5 kilovolts, peak powers over 100 kilowatts, and rise times less than 50 nanoseconds, with low stray inductance and capacitance, enhancing pulse repetition frequency and efficiency.
Implementation Method 1
a transformer electrically coupled with the plurality of switches, the transformer including at least one core, a plurality of primary windings wound at least partially around a portion of the at least one core, each of the plurality of switch modules electrically coupled with the primary windings; and a plurality of secondary windings wound at least partially around a portion of the core
Data Source
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AI summary
A nanosecond pulser may include a plurality of switch modules, a transformer, and an output. Each of the plurality of switch modules may include one or more solid state switches. The transformer may include a core, at least one primary winding wound around at least a portion of the core, each of the plurality of switch modules may be coupled with the primary windings, and a plurality of secondary windings wound at least partially around a portion of the core. The output may output electrical pulses having a peak voltage greater than about 1 kilovolt and having a pulse width of less than about 1000 nanoseconds. The output may output electrical pulses having a peak voltage greater than about 5 kilovolts, a peak power greater than about 100 kilowatts, a pulse width between 10 nanoseconds and 1000 nanoseconds, a rise time less than about 50 nanoseconds, or some combination thereof.