Application scenario of adaptive adaptation strategy for environmental parameters of solar inverter
The core of this strategy: real-time collection of radiation, temperature, humidity, altitude, salt fog, dust, wind speed, grid voltage/frequency and other environmental variables, dynamic correction of MPPT, heat dissipation, protection threshold, grid-connected control parameters, adaptation to changeable working conditions, improvement of power generation, reduction of failure rate and avoidance of abnormal off-grid load reduction. The following scenes are classified according to climate and geography, lighting and shadow scenes, power grid adaptation scenes, power station type scenes and special microgrid/optical storage scenes:
I. Extreme Climate and Special Geographical Environment Scenes
1. Hot and humid areas (desert in northwest China, high temperature in summer in South China)
Environmental pain points: high temperature power attenuation of components, overheating and derating of inverter power devices, and continuous power consumption of fans.
Adaptive strategy:
Component temperature compensation MPPT, real-time correction of maximum power point voltage;
Dynamically adjust the start-stop threshold of the fan and adjust the speed to dissipate heat. The higher the ambient temperature, the earlier the heat dissipation will start.
Adaptive load shedding protection of junction temperature to avoid overheating shutdown.
Typical projects: Gobi base, desert centralized photovoltaic power station
2. Cold and low temperature areas (Northeast China, Inner Mongolia, high latitude mountainous areas)
Environmental pain points: difficulty in starting at low temperature, capacitance characteristic deviation, MPPT tracking deviation, and large temperature difference between day and night.
Adaptive strategy: raise the threshold of fan start-up at low temperature to reduce useless power consumption, correct low-voltage start-up parameters, optimize PWM switching loss at low temperature and suppress low-temperature resonance.
3. High-altitude photovoltaic power stations (photovoltaic in mountainous areas over 2000m in western Sichuan, Xizang and Qinghai)
Environmental pain points: thin air leads to poor heat dissipation, decreased insulation strength, easy partial discharge and strong ultraviolet rays.
Adaptive strategies: altitude adaptive derating curve correction, heat dissipation power upward adjustment, dynamic adjustment of insulation protection threshold, adaptive relaxation of overvoltage protection margin to adapt to low-pressure insulation characteristics.
4. Coastal salt fog and high humidity environment (photovoltaic in southeast coast and island)
Environmental pain points: circuit board corrosion, insulation damp, leakage risk, accelerated device aging.
Adaptive strategies: humidity linkage insulation monitoring, adaptive leakage protection threshold, moisture-proof optimization of start-stop logic, and reducing impact switching frequency in humid environment.
5. Dust and dusty environment (northwest sandstorm area)
Environmental pain points: radiation attenuation due to component dust accumulation, and poor heat dissipation due to air duct blockage.
Adaptive strategy: radiation attenuation identification, MPPT adaptive compensation for power loss; Detect the trend of heat dissipation and blockage, and take the initiative to increase the speed for purging; The output of linkage cleaning system is adjusted to match the actual irradiation.
2. Complex scenes with violent lighting fluctuations and local shadows
1. Cloudy, cloudy and sunny areas
Pain point: the illumination suddenly rises and falls, the fixed step MPPT tracks slowly, the power oscillates, and the loss is large.
Self-adaptation: variable step-size adaptive MPPT, fast optimization in strong light and fine convergence in weak light in small steps, restraining vibration and improving power generation throughout the day.
2. Distributed photovoltaic with building shading, tree shadows and scattered roofs.
Pain points: series mismatch, multi-peak power curve and traditional MPPT trapped in local optimum.
Self-adaptation: multi-branch MPPT is self-adaptive, scanning the global maximum power point, and adjusting the disturbance frequency adaptively according to the shadow degree, thus greatly reducing the mismatch loss.
3. Working conditions of dim light in the morning and low irradiation in the morning and evening
Pain point: low voltage input is prone to vibration, low conversion efficiency and easy to trigger low voltage protection by mistake.
Self-adaptation: switch the parameters of low light mode, relax the low voltage protection threshold, reduce the switching frequency, reduce the loss and improve the utilization rate of low light.
Third, the power grid adaptation scenario (voltage/frequency fluctuation, weak current network)
1. Weak current network in rural distribution network and terminal area (high line impedance)
Pain point: the frequent occurrence of photovoltaic leads to terminal overvoltage, harmonic oscillation, and the inverter is prone to resonance off-grid.
Adaptive: adaptive virtual inertia VSG parameters, online impedance identification, dynamic reactive power voltage regulation, adaptive sag coefficient, suppression of resonance, and stable operation with low short-circuit ratio.
2. Frequent fluctuation areas of power grid voltage/frequency
Voltage fluctuation: adaptive reactive power regulation, over-voltage flexible power limit, low-voltage additional active power;
Frequency offset: adaptive primary frequency modulation response curve, no off-grid in the range of 47–52hz, and dynamic adjustment of active output to participate in frequency stabilization.
3. fault ride-through scene of power grid (voltage drop and sudden rise)
Adaptive adjustment of protection logic, current limiting parameters and modulation strategy can meet the standards of high and low voltage ride-through and avoid batch off-grid.
Iv. application of different types of photovoltaic power stations
1. Household distributed photovoltaic (residential roof)
The environment is changeable, the power grid capacity is small, and the shielding randomness is strong; Self-adaptive MPPT+low-voltage voltage regulation can reduce the power generation loss of householders and avoid the power grid from limiting the power generation when the voltage in the substation exceeds the standard.
2. Industrial and commercial roof photovoltaic
Large roof temperature difference, local shadow and large transformer load fluctuation; The inverter cluster cooperates with adaptive reactive power optimization and load linkage output adjustment to match the peak and valley of enterprise power consumption.
3. Mountainous and hilly photovoltaic power stations
Different slopes, messy orientation, local shadows, and large temperature difference between day and night; Cascade independent environmental adaptation, each MPPT independently matches the irradiation temperature characteristics.
4. Large-scale integrated base of scenery, fire and storage (Shagehuang base)
Large-scale climate imbalance, long-distance transmission weak network, extreme temperature difference between day and night; Self-adaptive scheduling of centralized inverter cluster in global environment, collaborative optimization of heat dissipation, grid connection and power, and reduction of overall derating loss.
Five, optical storage hybrid system, off-grid/microgrid special scene
1. All-in-one optical storage machine (parallel and off-grid dual mode)
Grid-connected mode is suitable for distribution network parameters; The off-grid microgrid mode adapts to sudden load change and light fluctuation, and adjusts the control parameters of voltage and frequency stabilization to ensure the stability of island power supply.
2. Stay away from grid photovoltaic (independent power supply in pastoral areas, frontier defense and islands)
No power grid support and extreme environment; According to illumination, battery SOC, the inverter can adaptively charge and discharge power and voltage stabilizing parameters to prevent over-charging and over-discharging, and improve the self-sustaining stability of the system.
3. Mobile photovoltaic (vehicle photovoltaic, container emergency power supply)
Dynamic changes of operating temperature and ventilation conditions; Real-time adaptive heat dissipation and power limitation, adapting to bumpy, closed and open-air alternating and changeable environment.
Sixth, energy-saving operation and maintenance and life cycle optimization scenarios
Energy-saving of cooling system: the wind speed is linked with the fan speed, so that the power consumption is reduced when there is wind, and the power consumption of the inverter is reduced when there is no wind to strengthen cooling;
Adaptive compensation for aging: long-term operation of device parameter drift, on-line identification of inverter, adaptive correction of control parameters, delay of efficiency attenuation;
Predictive operation and maintenance: based on the temperature and humidity and irradiation time series prediction, the MPPT and heat dissipation strategy are pre-adjusted in advance to predict the risks of overheating and overload and reduce downtime.
