Reasonable temperature control strategy can effectively reduce the loss of solar inverter, prolong its service life and improve its operation efficiency. The core idea is to accurately control the equipment temperature in the best working range (usually 25-45℃) to avoid over-temperature load reduction or low-temperature performance degradation. The following are several targeted temperature control strategies:
1. Active cooling intelligent adjustment strategy
The core heating components of solar inverter are IGBT, transformer, inductor, etc. Intelligent adjustment of active cooling system (fan, liquid cooling) is the key to improve efficiency.
Step-by-step temperature control and speed regulation: preset multi-step temperature thresholds to match the running power of cooling equipment. For example:
When the temperature is less than 35℃, the fan runs or stops at a low speed, reducing its own power consumption;
When the temperature is less than or equal to 35℃ and less than 45℃, the fan runs at a medium speed to maintain the balance between heat dissipation efficiency and power consumption;
When the temperature is ≥45℃, the fan runs at full speed to prevent the device from overheating and unloading.
Accurate heat dissipation by zones: Independent heat dissipation units are deployed in areas with different heating densities inside the inverter. For example, the IGBT module area uses a high-volume fan, and the control circuit area uses natural heat dissipation to avoid energy waste caused by the "one size fits all" heat dissipation mode.
Intelligent flow control of liquid cooling system: High-power photovoltaic inverters often use liquid cooling to dissipate heat, and the flow rate of cooling liquid is adjusted in real time through temperature sensors, which can increase the flow rate when the temperature rises and decrease the flow rate when the temperature drops. Compared with the constant flow mode, the energy consumption of the cooling system can be reduced by 10%–20%.
2. Passive heat dissipation optimization and thermal management strategy
By optimizing the equipment structure and heat dissipation materials, the heat accumulation is reduced and the workload of the active heat dissipation system is reduced.
Application of high-efficiency heat dissipation materials: High thermal conductivity materials such as graphene heat sink and aluminum heat dissipation fin are used to improve the heat exchange efficiency between devices and heat dissipation media and accelerate heat conduction.
Optimization of air duct and structure: design a straight-through air duct of "air inlet-heat absorption-air outlet" to reduce airflow resistance; Reasonable layout of components, avoid concentrated accumulation of heating components, and reduce the temperature of local hot spots.
Heat dissipation surface coating treatment: spray high radiation heat dissipation coating on the surface of heat dissipation fin to enhance heat radiation ability, especially suitable for outdoor installed inverter to improve natural heat dissipation effect.
3. Load and power adaptive temperature control strategy
The efficiency of inverter is closely related to the load rate (usually the efficiency is the highest when the load rate is 70%–100%), and the temperature control strategy combined with load change can achieve the best efficiency.
Load linkage speed regulation: when the inverter load rate is less than 30%, the heating power is low, which can reduce the fan speed or stop; When the load rate is more than or equal to 80%, increase the fan speed in advance to predict heat dissipation, so as to avoid sudden temperature rise due to sudden load increase.
Dynamic start and stop of power modules: A multi-module parallel high-power inverter starts and stops some power modules according to the load size, which reduces the standby loss of redundant modules, reduces the overall calorific value and indirectly reduces the heat dissipation energy consumption.
4. Environmental adaptive temperature control strategy
The cooling strategy is dynamically adjusted in combination with factors such as temperature, wind speed and sunshine in outdoor installation environment.
Environmental temperature compensation: when the outdoor temperature is low in winter, the threshold of fan start-up should be raised appropriately, and natural low temperature should be used to dissipate heat; When it is hot in summer, start the cooling system in advance to prevent the inverter from triggering load shedding protection due to excessive ambient temperature.
Induction adjustment of sunshine and wind speed: the intensity of sunshine and wind speed are monitored by sensors, and the heat dissipation is enhanced when the sunshine is strong, and the natural wind is used to assist the heat dissipation when the wind speed is high, thus reducing the running time of the fan.
5. Synergistic strategy of overheating protection and load shedding
When the temperature is close to the threshold, fine load shedding is used to replace direct shutdown, and the energy output efficiency is maximized under the premise of ensuring the safety of equipment.
Gradient load shedding temperature control: when the temperature reaches the early warning value (such as 55℃), the load is firstly shed by 10%-20% to reduce the heating power of the device; If the temperature continues to rise, the load will be further reduced to avoid the loss of power generation caused by sudden shutdown.
Fault early warning and maintenance tips: through temperature data monitoring, the faults of cooling system (such as abnormal fan speed and air duct blockage) can be predicted, and maintenance tips can be issued in time to prevent the efficiency from decreasing due to cooling failure.
Key points of strategy implementation
Accurate temperature measurement: install multi-point temperature sensors in key heating components (IGBT, transformer) to avoid the limitation of single point temperature measurement and ensure the accuracy of temperature control strategy.
Intelligent algorithm support: based on big data and machine learning, the mathematical model of "temperature-load-environment" is established to realize adaptive optimization of temperature control strategy and further improve the operation efficiency of inverter.
