doc figure
tells you how to use the figure command. Just create a figure then plot as a separate instruction, don't pass plot to figure as an argument - i.e.
figure; plot(V6,'DisplayName','60%');hold on;plot(V5,'DisplayName','50%');plot(V4,'DisplayName','40%');plot(V3,'DisplayName','30%');plot(V2,'DisplayName','20%');plot(V1,'DisplayName','10%');plot(V0,'DisplayName','0%');plot(Vminpu,'DisplayName','Vmin');hold off;);