A Maximum power point tracking (MPPT) system is essential for enhancing the efficiency of the PV system. There are various algorithms for the MPPT system that includes the traditional hill climbing MPPT, AI based MPPT and fixed voltage based algorithms. The testing of these algorithms is important to evaluate their performance under various kinds of environmental conditions. In the research community following are the test conditions applied on the MPPT system for its evaluation.
- Standard testing condition. The MPPT system is provided a standard testing condition of a PV module with 1000 W/m2 irradiance and temperature of 25 C.
- Step change in irradiance: To simulate the behavior of MPPT under dynamic weather condition the environmental parameters are changed in step mode. Usually irradiance is changed because in reality the change in temperature is slow. So the irradiance is changed from say 1000 W/m2 to 500 W/m2 and then to 200 W/m2 . This step change evaluates the system response under abrupt changes. It is pertinent to mention that in this testing condition not only the step change is applied in decreasing fashion but can also be applied in increasing mode i.e at starting from 500 W/m2 to 1000 W/m2 with step values of 100 or 50 or whatever. The step change increment and decrements are two different things and the algorithms particularly the hill climbing behaves differently. Therefore, the MPPT must be tested for both increasing irradiance as well as for decreasing irradiance.
Condition 2 for the testing of four different MPPT methods - The environmental conditions are changed gradually in ramp function. This testing condition simulates the normal weather condition with sunlight increasing linearly from sunrise to noon and then stays constant for few hours and then begins to descend in the same manner.
- Another weather condition can be simulated by merging point 2 and 3 to have a normal day scenario with abrupt changes in between. This simulates the birds or some building shade on the PV panel.
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