Water path protection control method for heat pump unit under pure off-grid and heat pump system

By using a DC inverter water pump and a flow switch in the heat pump unit, combined with speed and fault time judgment, the water flow failure problem when photovoltaic power generation is insufficient is solved, realizing stable operation of the heat pump unit and extending the life of the water pump.

CN122408306APending Publication Date: 2026-07-17ZHEJIANG DEYE ELECTRIC CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
ZHEJIANG DEYE ELECTRIC CO LTD
Filing Date
2026-04-20
Publication Date
2026-07-17

AI Technical Summary

Technical Problem

Under purely off-grid conditions, when photovoltaic power generation is insufficient, the water pump speed of the heat pump unit cannot be effectively controlled, leading to frequent water flow failures and affecting the unit's operational stability and lifespan.

Method used

By employing a DC inverter water pump and flow switch, combined with real-time speed and fault duration, a low-speed protection mode and fault diagnosis are triggered to avoid misjudgment and ensure stable operation of the unit when photovoltaic power is insufficient.

Benefits of technology

It improves the adaptability and stability of heat pump units in a purely off-grid environment, avoids water flow failure lock-up, ensures that the unit can quickly resume normal operation, extends the life of the water pump, and reduces maintenance costs.

✦ Generated by Eureka AI based on patent content.

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Abstract

This invention relates to the field of heat pump technology. It proposes a water circuit protection control method and system for a heat pump unit operating in a purely off-grid environment. The method includes: acquiring the real-time speed and operating duration of the DC inverter water pump; acquiring the duration of the water flow switch being open; triggering a low-speed protection mode when the duration of the DC inverter water pump's real-time speed being less than a first preset speed is greater than a first preset duration T1, and the duration of the water flow switch being open is greater than a second preset duration T2; if the duration of the water flow switch being open reaches a fourth preset duration T4 and the duration of the DC inverter water pump's real-time speed being greater than the second preset speed reaches a fifth preset duration T5, then triggering a water flow switch fault, until the DC inverter water pump is shut down for a predetermined duration and resets. This invention accurately determines the water flow condition through water pump speed and operating time, improving the adaptability and stability of photovoltaic direct-drive all-DC inverter heat pump units in a purely off-grid environment.
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