An implantable blood pump system comprising: a current sensor; and an implantable blood pump configured to be implanted at a patient's heart, the implantable blood pump comprising: a housing having an inlet and an outlet; a deformable membrane disposed within the housing; and an actuator comprising a stationary component and a moving component coupled to the deformable membrane, the actuator configured to be powered by an alternating current that causes the moving component to reciprocate at a predetermined frequency and amplitude relative to the stationary component, thereby causing the deformable membrane to produce a predetermined blood flow from the inlet out through the outlet; and a controller operatively coupled to the implantable blood pump, the controller being configured to: operate the actuator to cause the moving component to reciprocate at the predetermined frequency and amplitude relative to the stationary component; receive a signal indicative of the alternating current via the current sensor operatively coupled to the controller; determine a position of the moving component based on the signal indicative of the alternating current; and adjust operation of the actuator to cause the moving component to reciprocate at an adjusted predetermined frequency and amplitude relative to the stationary component based on the position of the moving component, thereby causing the deformable membrane to produce an adjusted predetermined blood flow from the inlet out through the outlet. a current sensor; and an implantable blood pump configured to be implanted at a patient's heart, the implantable blood pump comprising: a housing having an inlet and an outlet; a deformable membrane disposed within the housing; and an actuator comprising a stationary component and a moving component coupled to the deformable membrane, the actuator configured to be powered by an alternating current that causes the moving component to reciprocate at a predetermined frequency and amplitude relative to the stationary component, thereby causing the deformable membrane to produce a predetermined blood flow from the inlet out through the outlet; and a housing having an inlet and an outlet; a deformable membrane disposed within the housing; and an actuator comprising a stationary component and a moving component coupled to the deformable membrane, the actuator configured to be powered by an alternating current that causes the moving component to reciprocate at a predetermined frequency and amplitude relative to the stationary component, thereby causing the deformable membrane to produce a predetermined blood flow from the inlet out through the outlet; and operate the actuator to cause the moving component to reciprocate at the predetermined frequency and amplitude relative to the stationary component; receive a signal indicative of the alternating current via the current sensor operatively coupled to the controller; determine a position of the moving component based on the signal indicative of the alternating current; and adjust operation of the actuator to cause the moving component to reciprocate at an adjusted predetermined frequency and amplitude relative to the stationary component based on the position of the moving component, thereby causing the deformable membrane to produce an adjusted predetermined blood flow from the inlet out through the outlet.