Solar inverter is an electronic product and its service life is limited due to the limit of the components. However, many inverters are damaged before the service life expires and the actual service life is shorter than the designed theoretical service life. The service life is determined by the product quality and the post-period installation, operation and maintenance conditions. So, how to improve the service life of the solar inverter?
Internal temperature of the solar inverter
The temperature is an important factor that can affect the solar inverter service life and the excessively high temperature can decrease the property and service life of the component. Related researches prove that every time when the temperature increases by 10 degree, the service life of the electrolytic capacitor will be decreased by 50% and the failure rate of the power module will be doubled. Solar inverter is a heating generation device and its power module, inductor, switch, cable and other circuit will generate heat. These heat shall be dissipated in time and shall not be stored in a sealed space. Otherwise, the temperature will become higher and higher.
- The solar power inverter shall be placed in the ventilation space. If it is stored in indoor place, the indoor space shall be more than 10 times of the inverter size. It is suggested to install exhaust fans and other related device. If possible, the air conditioner can be installed.
- The direct sunlight shall be avoided. If the solar inverter is installed in outdoor place, it shall be installed along the wall or under the frame so that the sunlight can be blocked by the roof or the component. If the inverter has to be installed in an empty place, the sunshine shed shall be installed to prevent the inverter from rain or sunlight.
- If a few sets of on grid inverters are installed together, certain distance between the air outlet of one inverter and the air inlet of another inverter shall be guaranteed to ensure good heat dissipation. And this distance shall be at least 0.5m.
- The solar inverter shall be installed at a place away from the boilers, electric stoves, oil hot heater, heating pipes and other hot places.
- If the inverter output power is high, more heat energy will be generated. Thus, to prolong the service life, the matching ratio of the PV component and the inverter shall not greatly exceed the standard.
Solar inverter voltage and current
If people are always restless, angry and nervous, the immune system will be suppressed and destroyed under the long-term high pressure. Thus, people’s cardiovascular system will become vulnerable and people’s life will be affected. This is also true for the components. If the component bears high voltage and high current, the service life will be decreased accordingly.
- The solar power inverter input voltage shall meet certain range. For example, some range is 200-1000V. It means as long as the input voltage is in this range, the inverter can work normally. However, even though the input voltage is in this range, the PV inverter service life is different with different input voltage. When the component power is fixed, the series component voltage shall not be too high or too low. It is better to ensure the series component voltage is close to the inverter rated voltage. For instance, if the single-phase output voltage of the inverter is 220V, the series component voltage can be adjusted around 330V. If the three-phase output voltage of the inverter is 400V, the series component voltage can be set around 630V. Under these situations, the highest inverter efficiency and the highest safety can be guaranteed. If the series component voltage is set as 800V, the work efficiency of the solar inverter will be decreased and the power devices and current bus capacitors would bear high voltage. Thus, the service life of the insulation layer will be decreased and the inverter service life will be reduced.
- Under the same power condition, if the voltage is decreased and the current is increased, the inverter service life will be affected. For a 50kW grid tie inverter, if the DC voltage is set as 600V and the DC current will be around 100A. If the DC voltage is set as 400V, the DC current will be around 150V. As the heat of the inverter is mainly caused by the current, this configuration will increase the heat energy by 50%. The inverter temperature will be increased and the service life will be shortened.
External environment of the solar inverter
It is also very significant to create a good external environment for the solar inverter. Although PV inverter can meet IP65 outdoor protection condition and can prevent itself from the dust, rain and fog, the service life of the inverter in clean environment is longer than that of the PV inverter in dirt environment.
- It is better to install the solar power inverter in a sealed space when the external environment has serious pollution or heavy dust. This is because when dust falls down on the radiator, the heat radiation function will be affected. In addition, if dust, tree leaves and sand come into the air pipe of the inverter, the heat radiation function will also be affected.
- The solar inverter service life will also be affected by the power quality of the power grid. If the grid voltage is unstable or the grid harmonic is high, the inverter will start the protection function and will stop working when the voltage exceeds certain range. When the voltage is back to normal level, the inverter will start to work again. However, starting the inverter repeatedly will decrease the service life. What’s more, the service life can also be influenced by the system grounding, lightning protection, DC and AC circuit insulation conditions.
Summary
The designed service life of the PV inverter released from factory is same, but the real service life will be greatly affected by installation, operation and maintenance factors. To improve its service life, firstly a good installation environment shall be created to avoid the poor environment’s influence. On the other hand, the inverter shall be inspected frequently to find out any abnormal noise, odorless, abnormally high temperature or impurity. The inverter shall be maintained in clean status and the heat radiation pipe shall be smooth. The wire shall also be well connected.
