Modified Model-Reference Variable-Structure (MRVS) control methods are presented in the paper. Elimination of control signal chattering in order to reduce energy consumption is further shown. Four different integral optimization criterions with the following integral performance indices are described: integral of absolute value of function, integral of squared function, integral of time multiplied by absolute value of function and integral of time multiplied by squared function. Error signal, amount of energy consumption and their combination are used as functions in these integral performance indices for optimization of MRVS controller parameters. The presented integral optimization criterions are tested by computer simulations on modified MRVS direct-current motor control. MRVS controller parameters optimization results in further reduction of energy consumption. Modified MRVS control methods are tested with respect to load change, complex sinusoidal external disturbance and measurement noise and the simulation results show satisfactory robustness of all modified MRVS control methods.