While motors or generators stacked in series may allow for higher operating voltages, such motors or generators may also exhibit instability. To minimize instability, the motors or generators may be controlled to have an approximately equal current. An example motor system may include motor stacks connected in series, each motor stack exhibiting a respective stack voltage and a respective differential power (based on a difference in power between motors in the motor stack). A control system may average the stack voltages to generate an average stack voltage and generate a nominal stack power corresponding to each stack voltage. The control system may receive the differential powers, combine each differential power and nominal stack power for the respective motor stack to generate first and a second motor powers, and control each motor stack using the first and second motor powers.