Many modern commercial ships are electric ships, i.e., they utilize integrated electric propulsion (IEP ), where electric motors with variable speed drives are used for ship propulsion. This provides a number of advantages, such as reduced size and weight, electric power availability aboard the ship, reduced vibration, and more flexibility in generation engine placement by eliminating the mechanical connection between engines and propulsion. Most cruise ships, many yachts, and even cargo ships utilize IEP. There is also significant interest in IEP for military ships.