Precision Measurement in Fusion Energy Systems

Fusion energy is being pursued as a long-term solution for clean, reliable, and virtually limitless power generation. By replicating the processes that power the sun, fusion systems aim to produce energy without carbon emissions and with minimal waste. Unlike traditional generation methods, fusion offers the potential for high energy density with inherently safer operating conditions, making it an attractive path to contribute to grid expansion while energizing power demanding applications like AI Data Centers. Achieving this requires the confinement and control of extremely high-temperature plasma, typically using superconducting magnets operating at high currents and voltages within intense electromagnetic environments.

Key Measurement Needs in Fusion Systems

While fusion systems operate at substantial energy levels, many critical diagnostic measurements occur at very small signal levels, often in the millivolt to low-volt range. This creates a fundamental challenge to capture subtle electrical changes within an environment that simultaneously experiences kilovolt-level transients and significant electromagnetic noise. A key example is magnet voltage monitoring for quench detection. Under normal conditions, superconducting magnets operate under very cold temperatures to enable near-zero resistance, but when a disturbance occurs, a small resistive voltage drop develops that can indicate the onset of a quench event. A quench occurs when a portion of the superconducting material transitions to a normal resistive state, causing localized heating and current redistribution into the resistive region, resulting in an intense hotspot within the magnet. Rapid detection is critical, as this loss of superconductivity can trigger a release of stored energy that may damage downstream power electronics and control systems and potentially lead to a full system shutdown.

Beyond quench detection, voltage measurements also support stability analysis and equipment performance monitoring, providing real-time insight into system health. Across all these applications, the requirement remains consistent to accurately measure small signals in a high-voltage, electrically noisy environment.

Measurement Challenges

The primary challenge in fusion environments is true signal extraction. Rapidly changing magnetic fields and transients can generate induced voltages that are orders of magnitude larger than the actual measurement signals of interest. These effects can obscure meaningful data if not properly managed and failure to properly isolate these signals can result in damage.

This is further complicated by high common-mode voltages that can exist, making it difficult to resolve small differential signals and not introduce error. Without sufficient common-mode rejection, measurement accuracy is impacted and system performance is diminished.

Knick’s Role in Fusion Measurement Systems

Knick monitoring solutions are designed to address these conditions by enabling precise measurement of low-level electrical signals in high-voltage environments. Through galvanic isolation between input, output, and power supply, these systems prevent the transfer of dangerous voltages while maintaining signal integrity. This isolation allows small differential signals to be measured safely, even when imposed by high common-mode voltages.

In addition, high common-mode rejection ensures stable operation and measurements in the electrically noisy conditions, which enables an efficient and precise control architecture.

This combination allows fusion system developers to reliably capture critical diagnostic data while protecting both instrumentation and downstream systems and operators. By feeding accurate, isolated signals into control and safety circuits, these measurements allow for fast protective actions such as quench detection and system shutdown, supporting safer operation and improved long-term system reliability.