POWER CONDITIONING

Contents:

1. Introduction
2. Why we need power conditioning
3. Our choice of Inverter
4. Efficiencies
5. Conclusion

3. OUR CHOICE OF INVERTER

What type of inverter is best for our needs?

Inverters range from cheap square wave inverters to more expensive and sophisticated 'true' sine wave inverters. Square wave inverters simply change a DC current to a square AC waveform. However, square wave inverters can damage or overheat appliances. The inverter we choose must have the following characteristics:

1. High surge capacity (for when motors are switched on)
2. Output voltage regulation
3. High efficiency
4. Low harmonics
5. Low audio and RF noise (to minimise radio interference)

It is now common practice for inverters to include a peak power tracker (PPT). In the process of converting DC to AC, the PPT constantly adjusts its input voltage in order to maximise the product of input current and voltage. The PPT is important because it maximises the power extracted as the irradiance from the PV and the charge from the fuel cell varies. This is one point to mention in our favour — stand-alone inverters are simpler and cheaper than those needed for grid connection. This is because the quality of the waveform supplied to the grid must be very high.

Efficiencies