Priority based power sharing in parallel connected boost converters is one of the simplest power sharing scheme to run the boost converters in parallel operation. in this simulation it is considered that the boost converters are physically not far from each other, and the controllers of the converters can communicate with other. One of the converters will run on higher priority which means that that converter will supply as much power as it can to the bus, and another will only supply additional power required to maintain bus stability i.e: maintain the bus voltage. Following figure shows the hardware setup of the experiment.
Figure: Boost converter parallel operation experimental setup
this configuration of the converter is applicable in the conditions where we need to draw as much power from a source as possible and draw only additional power required to maintain bus voltage from the secondary source. An example application case would be when there is a solar and battery-based home electrifying system, and we want to draw as much power from the solar as possible and only draw additional power from the battery. Following figure shows the schematic of parallel connected boost converters used in this experiment.
Figure: parallel connected boost converters
In this simulation the current limit for first priority source is set at 5 A so when first priority source is not able to supply enough power to keep the boost converter output stable at given voltage than additional power required to supply enough output power and keep the output voltage stable will be drawn from second source. the converter output is controlled by PID controller by controlling the duty cycle of gate PWM of the MOSFET.
Figure: Bus voltage and current waveforms of the converters under load changing conditions
this type of circuit can be implemented in DC transmission system where the power from certain source is preferred over others than this circuit can be used to draw maximum possible power from preferred source and only draw additional power from secondary source.
In this circuit single controller is used to control both converters. when the power requirement increases than duty cycle for preferred converter starts to increase, when duty cycle of preferred controller reaches its limit than duty cycle of second controller starts to increase. Same operation happens in reverse when the power needs to be decreased.
Figure: MATLAB Simulink setup