Analysis of Control Circuit for Photovoltaic Junction Box

1. Currently, inverters with square wave output mostly use pulse width modulation integrated circuits, such as SG3525, TL494, etc. Practice has proven that using the SG3525 integrated circuit and using power field-effect transistors as switching power components can achieve a high-performance and cost-effective inverter. Due to the ability of SG3525 to directly drive power field-effect transistors, as well as its internal reference source, operational amplifier, and undervoltage protection functions, its peripheral circuit is very simple.

2. The inverter control integrated circuit for sine wave output can be controlled by a microprocessor. These microcontrollers all have multiple PWM generators and can set the dead time between the upper and upper bridge arms. The 80C196N circuit is used to achieve sine wave output, and the 80C196N circuit is used to generate sine wave signals and detect AC output voltage to achieve voltage stabilization.

Selection of power devices for the main circuit of photovoltaic junction box inverter:

The selection of the main power components of inverters is crucial. Currently, the commonly used power components include Darlington power transistors, power field-effect transistors, insulated-gate transistors, and turn-off thyristors. In small capacity and low voltage systems, the most commonly used component is MOSFETs, which have lower on state voltage drop and higher switching frequency. In high voltage and large capacity systems, IGBT modules are generally used, This is because as the voltage increases, the on-state resistance of MOSFETs also increases, and IGBTs have a significant advantage in medium capacity systems, while in ultra large capacity systems, GTO is generally used as the power component.