  The efficiency at maximum power has been investigated extensively, yet the
practical control scheme to achieve it remains elusive. We fill such gap with a
stepwise Carnot-like cycle, which consists the discrete isothermal process
(DIP) and adiabatic process. With DIP, we validate the widely adopted
assumption of \mathscr{C}/t relation of the irreversible entropy generation
S^{(\mathrm{ir})}, and show the explicit dependence of the coefficient
\mathscr{C} on the fluctuation of the speed of tuning energy levels as well as
the microscopic coupling constants to the heat baths. Such dependence allows to
control the irreversible entropy generation by choosing specific control
schemes. We further demonstrate the achievable efficiency at maximum power and
the corresponding control scheme with the simple two-level system. Our current
work opens new avenues for the experimental test, which was not feasible due to
the lack the of the practical control scheme in the previous low-dissipation
model or its equivalents.
