Controller for grid tied inverter system

A controller for a grid tied inverter system, the inverter system comprising a direct current (DC) DC-DC converter connected to an output of a DC energy supply source, and an inverter connected to an output of the DC-DC converter and configured to invert a DC voltage applied from the DC energy supply source into an alternating current (AC) grid voltage and supply the inverted AC grid voltage to a grid,

• the controller comprising:
• a first control circuit section configured to output a DC-DC converter control signal for controlling the DC-DC converter;
• and
• a second control circuit section configured to output an inverter control signal for controlling the inverter,
• wherein the first control circuit section and the second control circuit section are independent of each other due to a non-link of signal input and output therebetween,
• wherein the second control circuit section comprises:
• an input voltage control circuit section configured to generate an output current command by proportional integrating a difference between an input voltage command from the input voltage control circuit section and an input voltage from the DC energy source;
• and
• an output current control circuit section configured to generate the inverter control signal based only on proportional integrating a difference between the output current command and an input current from the DC energy source and to output the generated inverter control signal directly to the inverter.