1. Core Principle Summary
In simple terms, its core principle can be summarized as a three-step AC-DC-AC conversion, with the key step being to increase the frequency first, then transform the voltage.
2. Working Principle
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Rectification：First, the input line-frequency AC power (e.g., 50 Hz or 60 Hz) is rectified into DC power using power electronic devices (such as IGBTs). This step converts low-frequency AC into stable DC, preparing it for subsequent processing.
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High-Frequency Chopping (Inversion)：Next, the rectified DC power is inverted into high-frequency AC power (from several kilohertz to hundreds of kilohertz) by controlling switching devices. This is the core step: according to transformer principles, at the same power level, higher frequency reduces the required core volume. Therefore, increasing the frequency drastically reduces the size and weight of the main transformer.
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Isolation and Voltage Transformation via High-Frequency Transformer：This high-frequency AC power then enters a compact high-frequency transformer. Through electromagnetic induction, the transformer performs voltage transformation and provides electrical isolation. Due to the high operating frequency, this small transformer is typically more energy-efficient than a traditional line-frequency transformer.
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Final Rectification/Inversion for Output：The transformed high-frequency AC power is then converted into the required form of electrical energy. This may involve rectifying it back into DC power for use in DC microgrids or EV chargers, or inverting it into AC power. In the latter case, voltage, frequency, and phase are precisely regulated before the power is supplied to AC loads or connected to the grid.
As you can see, the solid-state transformer is much smaller and lighter than traditional transformers. Moreover, thanks to the intermediate DC link, it does more than just transform voltage—it can act like an energy router, easily integrating renewable energy sources (e.g., photovoltaics) and energy storage systems, dynamically regulating power flow, and improving power quality.
3. Your Technical Sentence (retained as requested)
Solid-state circuit breakers with SiC MOSFETs enable microsecond-level interruption, eliminate arc flash, realize precise selective coordination, and revolutionize low-voltage circuit protection with high safety and efficiency.
