In a photovoltaic DC boosting collection system

the output voltage of the photovoltaic side cascade boost converter unit caused by the uneven illumination of the series photovoltaic unit is unbalanced

and the traditional control strategy is difficult to realize the maximum power point tracking（MPPT） control of the photovoltaic module with lower photovoltaic output. We put forward a weight hierarchical control strategy based on slope control. The output voltage of the boost converter was adjusted according to the change of the power weight difference between the photovoltaic modules to improve the port voltage of the low output voltage module to meet MPPT mode requirements. Moreover

we analyzed the principle of the weight hierarchical control strategy and the effect of isolated DC/DC converter duty cycle on MPPT control. The effectiveness of this strategy was verified by MATLAB/Simulink. The results show that

the proposed control strategy can be adopted to realize the MPPT working mode of the module with lower power weight when the irradiation is not balanced

therefore

the characteristics of the grid-connected output of the photovoltaic system can be improved

and the smooth switching of the control mode can be realized. The research of the paper can provide references for the control of photovoltaic DC boost collection system.