Efficient single switch isolated high step up DC-DC converter with constant output voltage for solar energy sources

In this project work, an efficient single switch isolated high step up DC-DC converter for solar energy sources is proposed. Solar panels are of high cost, low efficient and intermittent source which make them less advantageous. Thus, using an efficient high step up converter can be more cost effective and can improve the efficiency. The disadvantage of conventional converters such as switching losses and reverse recovery problem can be overcome in this proposed converter. Using single switch can also improve efficiency. The isolated transformer is connected in series during switching operation, thereby achieving a high voltage gain. The solar irradiance available in nature varies, due to which the solar PV changes its output voltage. This varying output voltage from the solar PV may affect the electrical apparatus or even may damage them. Thus, a constant output voltage method of control is used here. The output voltage and current from the converter is compared with the reference value to generate an error pulse signal. This error is minimized by using a PI controller. Using this minimized error signal, switching pulse for the converter is generated by the PWM generator to obtain a constant output voltage. Thus, a constant output voltage is obtained from the converter irrespective of the varying irradiance.