Cooling continuity engineering
Voltage Sag Ride-Through for Data Center Chiller VFDs
A short voltage sag can cause a chiller compressor VFD to trip on undervoltage. Assess engineered DC-link support together with the control-power protection needed to keep the intended cooling process operating.
Start with the compressor drive and the full protection boundary.
Compressor VFDs with a suitable, manufacturer-approved DC bus / DC link interface can be evaluated for short ride-through. Review pumps and fans separately. Keeping the inverter output active does not automatically keep the complete chiller or cooling system running: control supplies, interlocks, contactors and critical auxiliaries must also remain functional.
One cabinet may support multiple drives only after reviewing simultaneous power and energy demand, each branch’s isolation and fault protection, voltage compatibility and control behavior. Do not short independent DC buses together. Coordinate small UPS or control-power backup, flywheel DC-link support and feeder-level DVR protection where the load boundaries require them.
Share what you know; unknown values can follow.
| If available | Purpose of the review |
|---|---|
| VFD make/model and DC voltage window | Confirm approved interface, precharge, braking and protection requirements. |
| Actual operating kW and target duration | Define the power–energy duty and its operating conditions. |
| Simultaneous drive count | Assess combined demand and separately protected branches. |
| Control power, project stage and country | Review process dependencies and applicable project requirements. |
This is a short-duration engineering protection approach. It does not replace server UPS systems or site backup power. Product and project compliance, including any required North American certification, must be verified for the proposed configuration.
Review industrial deployment evidence.
The Fujian and Hangzhou textile cases document industrial applications with defined record periods. They are not data center chiller operating references.